NEWS
author wenzelm
Tue Jul 31 13:31:01 2007 +0200 (2007-07-31)
changeset 24086 21900a460ba4
parent 24032 b3d7eb6f535f
child 24110 4ab3084e311c
permissions -rw-r--r--
* Configuration options;
* Named collections of theorems;
     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 * Configuration options are maintained within the theory or proof
   165 context (with name and type bool/int/string), providing a very simple
   166 interface to a poor-man's version of general context data.  Tools may
   167 declare options in ML (e.g. using ConfigOption.int) and then refer to
   168 these values using ConfigOption.get etc.  Users may change options via
   169 the "option" attribute, which works particularly well with commands
   170 'declare' or 'using', for example ``declare [[option foo = 42]]''.
   171 Thus global reference variables are easily avoided, which do not
   172 observe Isar toplevel undo/redo and fail to work with multithreading.
   173 
   174 * Named collections of theorems may be easily installed as context
   175 data using the functor NamedThmsFun (see
   176 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   177 attributes.  This is just a common case of general context data, which
   178 is the preferred way for anything more complex than just a list of
   179 facts in canonical order.
   180 
   181 * Isar: command 'declaration' augments a local theory by generic
   182 declaration functions written in ML.  This enables arbitrary content
   183 being added to the context, depending on a morphism that tells the
   184 difference of the original declaration context wrt. the application
   185 context encountered later on.
   186 
   187 * Isar: proper interfaces for simplification procedures.  Command
   188 'simproc_setup' declares named simprocs (with match patterns, and body
   189 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   190 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   191 
   192 * Isar: an extra pair of brackets around attribute declarations
   193 abbreviates a theorem reference involving an internal dummy fact,
   194 which will be ignored later --- only the effect of the attribute on
   195 the background context will persist.  This form of in-place
   196 declarations is particularly useful with commands like 'declare' and
   197 'using', for example ``have A using [[simproc a]] by simp''.
   198 
   199 * Isar: method "assumption" (and implicit closing of subproofs) now
   200 takes simple non-atomic goal assumptions into account: after applying
   201 an assumption as a rule the resulting subgoals are solved by atomic
   202 assumption steps.  This is particularly useful to finish 'obtain'
   203 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   204 without referring to the original premise "!!x. P x ==> thesis" in the
   205 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   206 more permissive.
   207 
   208 * Isar: implicit use of prems from the Isar proof context is
   209 considered a legacy feature.  Common applications like ``have A .''
   210 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   211 referencing facts explicitly here improves readability and
   212 maintainability of proof texts.
   213 
   214 * Isar: improper proof element 'guess' is like 'obtain', but derives
   215 the obtained context from the course of reasoning!  For example:
   216 
   217   assume "EX x y. A x & B y"   -- "any previous fact"
   218   then guess x and y by clarify
   219 
   220 This technique is potentially adventurous, depending on the facts and
   221 proof tools being involved here.
   222 
   223 * Isar: known facts from the proof context may be specified as literal
   224 propositions, using ASCII back-quote syntax.  This works wherever
   225 named facts used to be allowed so far, in proof commands, proof
   226 methods, attributes etc.  Literal facts are retrieved from the context
   227 according to unification of type and term parameters.  For example,
   228 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   229 theorems in the current context, then these are valid literal facts:
   230 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   231 
   232 There is also a proof method "fact" which does the same composition
   233 for explicit goal states, e.g. the following proof texts coincide with
   234 certain special cases of literal facts:
   235 
   236   have "A" by fact                 ==  note `A`
   237   have "A ==> B" by fact           ==  note `A ==> B`
   238   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   239   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   240 
   241 * Isar: ":" (colon) is no longer a symbolic identifier character in
   242 outer syntax.  Thus symbolic identifiers may be used without
   243 additional white space in declarations like this: ``assume *: A''.
   244 
   245 * Isar: 'print_facts' prints all local facts of the current context,
   246 both named and unnamed ones.
   247 
   248 * Isar: 'def' now admits simultaneous definitions, e.g.:
   249 
   250   def x == "t" and y == "u"
   251 
   252 * Isar: added command 'unfolding', which is structurally similar to
   253 'using', but affects both the goal state and facts by unfolding given
   254 rewrite rules.  Thus many occurrences of the 'unfold' method or
   255 'unfolded' attribute may be replaced by first-class proof text.
   256 
   257 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   258 and command 'unfolding' now all support object-level equalities
   259 (potentially conditional).  The underlying notion of rewrite rule is
   260 analogous to the 'rule_format' attribute, but *not* that of the
   261 Simplifier (which is usually more generous).
   262 
   263 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   264 method expression within a sandbox consisting of the first N
   265 sub-goals, which need to exist.  For example, ``simp_all [3]''
   266 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   267 simplifies all new goals that emerge from applying rule foo to the
   268 originally first one.
   269 
   270 * Isar: schematic goals are no longer restricted to higher-order
   271 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   272 expected.
   273 
   274 * Isar: the conclusion of a long theorem statement is now either
   275 'shows' (a simultaneous conjunction, as before), or 'obtains'
   276 (essentially a disjunction of cases with local parameters and
   277 assumptions).  The latter allows to express general elimination rules
   278 adequately; in this notation common elimination rules look like this:
   279 
   280   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   281     assumes "EX x. P x"
   282     obtains x where "P x"
   283 
   284   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   285     assumes "A & B"
   286     obtains A and B
   287 
   288   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   289     assumes "A | B"
   290     obtains
   291       A
   292     | B
   293 
   294 The subsequent classical rules even refer to the formal "thesis"
   295 explicitly:
   296 
   297   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   298     obtains "~ thesis"
   299 
   300   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   301     obtains "thesis ==> something"
   302 
   303 The actual proof of an 'obtains' statement is analogous to that of the
   304 Isar proof element 'obtain', only that there may be several cases.
   305 Optional case names may be specified in parentheses; these will be
   306 available both in the present proof and as annotations in the
   307 resulting rule, for later use with the 'cases' method (cf. attribute
   308 case_names).
   309 
   310 * Isar: the assumptions of a long theorem statement are available as
   311 "assms" fact in the proof context.  This is more appropriate than the
   312 (historical) "prems", which refers to all assumptions of the current
   313 context, including those from the target locale, proof body etc.
   314 
   315 * Isar: 'print_statement' prints theorems from the current theory or
   316 proof context in long statement form, according to the syntax of a
   317 top-level lemma.
   318 
   319 * Isar: 'obtain' takes an optional case name for the local context
   320 introduction rule (default "that").
   321 
   322 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   323 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   324 to occur.
   325 
   326 * Pure: syntax "CONST name" produces a fully internalized constant
   327 according to the current context.  This is particularly useful for
   328 syntax translations that should refer to internal constant
   329 representations independently of name spaces.
   330 
   331 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   332 instead of "FOO ". This allows multiple binder declarations to coexist
   333 in the same context.  INCOMPATIBILITY.
   334 
   335 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   336 primitive that also works in a locale context (both for constants and
   337 fixed variables).  Type declaration and internal syntactic
   338 representation of given constants retrieved from the context.
   339 
   340 * Isar/locales: new derived specification elements 'axiomatization',
   341 'definition', 'abbreviation', which support type-inference, admit
   342 object-level specifications (equality, equivalence).  See also the
   343 isar-ref manual.  Examples:
   344 
   345   axiomatization
   346     eq  (infix "===" 50) where
   347     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   348 
   349   definition "f x y = x + y + 1"
   350   definition g where "g x = f x x"
   351 
   352   abbreviation
   353     neq  (infix "=!=" 50) where
   354     "x =!= y == ~ (x === y)"
   355 
   356 These specifications may be also used in a locale context.  Then the
   357 constants being introduced depend on certain fixed parameters, and the
   358 constant name is qualified by the locale base name.  An internal
   359 abbreviation takes care for convenient input and output, making the
   360 parameters implicit and using the original short name.  See also
   361 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   362 entities from a monomorphic theory.
   363 
   364 Presently, abbreviations are only available 'in' a target locale, but
   365 not inherited by general import expressions.  Also note that
   366 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   367 'translations' in common applications.
   368 
   369 Concrete syntax is attached to specified constants in internal form,
   370 independently of name spaces.  The parse tree representation is
   371 slightly different -- use 'notation' instead of raw 'syntax', and
   372 'translations' with explicit "CONST" markup to accommodate this.
   373 
   374 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   375 the current context.  Print mode "no_abbrevs" prevents inversion of
   376 abbreviations on output.
   377 
   378 * Isar/locales: improved parameter handling:
   379 - use of locales "var" and "struct" no longer necessary;
   380 - parameter renamings are no longer required to be injective.
   381   This enables, for example, to define a locale for endomorphisms thus:
   382   locale endom = homom mult mult h.
   383 
   384 * Isar/locales: changed the way locales with predicates are defined.
   385 Instead of accumulating the specification, the imported expression is
   386 now an interpretation.  INCOMPATIBILITY: different normal form of
   387 locale expressions.  In particular, in interpretations of locales with
   388 predicates, goals repesenting already interpreted fragments are not
   389 removed automatically.  Use methods `intro_locales' and
   390 `unfold_locales'; see below.
   391 
   392 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   393 provide backward reasoning on locales predicates.  The methods are
   394 aware of interpretations and discharge corresponding goals.
   395 `intro_locales' is less aggressive then `unfold_locales' and does not
   396 unfold predicates to assumptions.
   397 
   398 * Isar/locales: the order in which locale fragments are accumulated
   399 has changed.  This enables to override declarations from fragments due
   400 to interpretations -- for example, unwanted simp rules.
   401 
   402 * Isar/locales: interpretation in theories and proof contexts has been
   403 extended.  One may now specify (and prove) equations, which are
   404 unfolded in interpreted theorems.  This is useful for replacing
   405 defined concepts (constants depending on locale parameters) by
   406 concepts already existing in the target context.  Example:
   407 
   408   interpretation partial_order ["op <= :: [int, int] => bool"]
   409     where "partial_order.less (op <=) (x::int) y = (x < y)"
   410 
   411 Typically, the constant `partial_order.less' is created by a definition
   412 specification element in the context of locale partial_order.
   413 
   414 * Provers/induct: improved internal context management to support
   415 local fixes and defines on-the-fly.  Thus explicit meta-level
   416 connectives !! and ==> are rarely required anymore in inductive goals
   417 (using object-logic connectives for this purpose has been long
   418 obsolete anyway).  The subsequent proof patterns illustrate advanced
   419 techniques of natural induction; general datatypes and inductive sets
   420 work analogously (see also src/HOL/Lambda for realistic examples).
   421 
   422 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   423 parameters:
   424 
   425   lemma
   426     fixes n :: nat and x :: 'a
   427     assumes a: "A n x"
   428     shows "P n x"
   429     using a                     -- {* make induct insert fact a *}
   430   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   431     case 0
   432     show ?case sorry
   433   next
   434     case (Suc n)
   435     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   436     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   437     show ?case sorry
   438   qed
   439 
   440 (2) This is how to perform induction over ``expressions of a certain
   441 form'', using a locally defined inductive parameter n == "a x"
   442 together with strengthening (the latter is usually required to get
   443 sufficiently flexible induction hypotheses):
   444 
   445   lemma
   446     fixes a :: "'a => nat"
   447     assumes a: "A (a x)"
   448     shows "P (a x)"
   449     using a
   450   proof (induct n == "a x" arbitrary: x)
   451     ...
   452 
   453 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   454 particular technique.
   455 
   456 (3) This is how to perform existential reasoning ('obtains' or
   457 'obtain') by induction, while avoiding explicit object-logic
   458 encodings:
   459 
   460   lemma
   461     fixes n :: nat
   462     obtains x :: 'a where "P n x" and "Q n x"
   463   proof (induct n arbitrary: thesis)
   464     case 0
   465     obtain x where "P 0 x" and "Q 0 x" sorry
   466     then show thesis by (rule 0)
   467   next
   468     case (Suc n)
   469     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   470     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   471     then show thesis by (rule Suc.prems)
   472   qed
   473 
   474 Here the 'arbitrary: thesis' specification essentially modifies the
   475 scope of the formal thesis parameter, in order to the get the whole
   476 existence statement through the induction as expected.
   477 
   478 * Provers/induct: mutual induction rules are now specified as a list
   479 of rule sharing the same induction cases.  HOL packages usually
   480 provide foo_bar.inducts for mutually defined items foo and bar
   481 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   482 specify mutual induction rules differently, i.e. like this:
   483 
   484   (induct rule: foo_bar.inducts)
   485   (induct set: foo bar)
   486   (induct type: foo bar)
   487 
   488 The ML function ProjectRule.projections turns old-style rules into the
   489 new format.
   490 
   491 * Provers/induct: improved handling of simultaneous goals.  Instead of
   492 introducing object-level conjunction, the statement is now split into
   493 several conclusions, while the corresponding symbolic cases are
   494 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   495 explicitly.  For example:
   496 
   497   lemma
   498     fixes n :: nat
   499     shows "P n" and "Q n"
   500   proof (induct n)
   501     case 0 case 1
   502     show "P 0" sorry
   503   next
   504     case 0 case 2
   505     show "Q 0" sorry
   506   next
   507     case (Suc n) case 1
   508     note `P n` and `Q n`
   509     show "P (Suc n)" sorry
   510   next
   511     case (Suc n) case 2
   512     note `P n` and `Q n`
   513     show "Q (Suc n)" sorry
   514   qed
   515 
   516 The split into subcases may be deferred as follows -- this is
   517 particularly relevant for goal statements with local premises.
   518 
   519   lemma
   520     fixes n :: nat
   521     shows "A n ==> P n" and "B n ==> Q n"
   522   proof (induct n)
   523     case 0
   524     {
   525       case 1
   526       note `A 0`
   527       show "P 0" sorry
   528     next
   529       case 2
   530       note `B 0`
   531       show "Q 0" sorry
   532     }
   533   next
   534     case (Suc n)
   535     note `A n ==> P n` and `B n ==> Q n`
   536     {
   537       case 1
   538       note `A (Suc n)`
   539       show "P (Suc n)" sorry
   540     next
   541       case 2
   542       note `B (Suc n)`
   543       show "Q (Suc n)" sorry
   544     }
   545   qed
   546 
   547 If simultaneous goals are to be used with mutual rules, the statement
   548 needs to be structured carefully as a two-level conjunction, using
   549 lists of propositions separated by 'and':
   550 
   551   lemma
   552     shows "a : A ==> P1 a"
   553           "a : A ==> P2 a"
   554       and "b : B ==> Q1 b"
   555           "b : B ==> Q2 b"
   556           "b : B ==> Q3 b"
   557   proof (induct set: A B)
   558 
   559 * Provers/induct: support coinduction as well.  See
   560 src/HOL/Library/Coinductive_List.thy for various examples.
   561 
   562 * Attribute "symmetric" produces result with standardized schematic
   563 variables (index 0).  Potential INCOMPATIBILITY.
   564 
   565 * Simplifier: by default the simplifier trace only shows top level
   566 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   567 default. Thus there is less danger of being flooded by the trace. The
   568 trace indicates where parts have been suppressed.
   569   
   570 * Provers/classical: removed obsolete classical version of elim_format
   571 attribute; classical elim/dest rules are now treated uniformly when
   572 manipulating the claset.
   573 
   574 * Provers/classical: stricter checks to ensure that supplied intro,
   575 dest and elim rules are well-formed; dest and elim rules must have at
   576 least one premise.
   577 
   578 * Provers/classical: attributes dest/elim/intro take an optional
   579 weight argument for the rule (just as the Pure versions).  Weights are
   580 ignored by automated tools, but determine the search order of single
   581 rule steps.
   582 
   583 * Syntax: input syntax now supports dummy variable binding "%_. b",
   584 where the body does not mention the bound variable.  Note that dummy
   585 patterns implicitly depend on their context of bounds, which makes
   586 "{_. _}" match any set comprehension as expected.  Potential
   587 INCOMPATIBILITY -- parse translations need to cope with syntactic
   588 constant "_idtdummy" in the binding position.
   589 
   590 * Syntax: removed obsolete syntactic constant "_K" and its associated
   591 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   592 for example "A -> B" => "Pi A (%_. B)".
   593 
   594 * Pure: 'class_deps' command visualizes the subclass relation, using
   595 the graph browser tool.
   596 
   597 * Pure: 'print_theory' now suppresses entities with internal name
   598 (trailing "_") by default; use '!' option for full details.
   599 
   600 
   601 *** HOL ***
   602 
   603 * Code generator library theories:
   604   * Pretty_Int represents HOL integers by big integer literals in target
   605     languages.
   606   * Pretty_Char represents HOL characters by character literals in target
   607     languages.
   608   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   609     codes; includes Pretty_Int.
   610   * Executable_Set allows to generate code for finite sets using lists.
   611   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   612     denominator).
   613   * Executable_Real implements a subset of real numbers, namly those
   614     representable by rational numbers.
   615   * Efficient_Nat implements natural numbers by integers, which in general will
   616     result in higher efficency; pattern matching with 0/Suc is eliminated;
   617     includes Pretty_Int.
   618   * ML_String provides an additional datatype ml_string; in the HOL default
   619     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   620     of type ml_string are mapped to strings in SML.
   621   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   622     built-in integers.
   623 
   624 * New package for inductive predicates
   625 
   626   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   627 
   628     inductive
   629       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   630       for z_1 :: U_1 and ... and z_n :: U_m
   631     where
   632       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   633     | ...
   634 
   635   rather than
   636 
   637     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   638 
   639     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   640     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   641 
   642     inductive "s z_1 ... z_m"
   643     intros
   644       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   645       ...
   646 
   647   For backward compatibility, there is a wrapper allowing inductive
   648   sets to be defined with the new package via
   649 
   650     inductive_set
   651       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   652       for z_1 :: U_1 and ... and z_n :: U_m
   653     where
   654       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   655     | ...
   656 
   657   or
   658 
   659     inductive_set
   660       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   661       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   662       for z_1 :: U_1 and ... and z_n :: U_m
   663     where
   664       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   665     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   666     | ...
   667 
   668   if the additional syntax "p ..." is required.
   669 
   670   Many examples can be found in the subdirectories Auth, Bali, Induct,
   671   or MicroJava.
   672 
   673   INCOMPATIBILITIES:
   674 
   675   - Since declaration and definition of inductive sets or predicates
   676     is no longer separated, abbreviations involving the newly introduced
   677     sets or predicates must be specified together with the introduction
   678     rules after the "where" keyword (see example above), rather than before
   679     the actual inductive definition.
   680 
   681   - The variables in induction and elimination rules are now quantified
   682     in the order of their occurrence in the introduction rules, rather than
   683     in alphabetical order. Since this may break some proofs, these proofs
   684     either have to be repaired, e.g. by reordering the variables
   685     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   686 
   687       case (rule_i a_i_1 ... a_i_{k_i})
   688 
   689     or the old order of quantification has to be restored by explicitly adding
   690     meta-level quantifiers in the introduction rules, i.e.
   691 
   692       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   693 
   694   - The format of the elimination rules is now
   695 
   696       p z_1 ... z_m x_1 ... x_n ==>
   697         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   698         ==> ... ==> P
   699 
   700     for predicates and
   701 
   702       (x_1, ..., x_n) : s z_1 ... z_m ==>
   703         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   704         ==> ... ==> P
   705 
   706     for sets rather than
   707 
   708       x : s z_1 ... z_m ==>
   709         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   710         ==> ... ==> P
   711 
   712     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   713     or simplification with the split_paired_all rule) before the above elimination
   714     rule is applicable.
   715 
   716   - The elimination or case analysis rules for (mutually) inductive sets or
   717     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   718     "p_1_..._p_k.elims" is no longer available.
   719 
   720 * Method "metis" proves goals by applying the Metis general-purpose
   721 resolution prover.  Examples are in the directory MetisExamples.  See
   722 also http://gilith.com/software/metis/
   723   
   724 * Command 'sledgehammer' invokes external automatic theorem provers as
   725 background processes.  It generates calls to the "metis" method if
   726 successful. These can be pasted into the proof.  Users do not have to
   727 wait for the automatic provers to return.
   728 
   729 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   730   take their order into account, like in functional programming.
   731   Internally, this is translated into nested case-expressions; missing cases
   732   are added and mapped to the predefined constant "undefined". In complicated
   733   cases printing may no longer show the original input but the internal
   734   form. Lambda-abstractions allow the same form of pattern matching:
   735   "% pat1 => e1 | ..." is an abbreviation for
   736   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   737 
   738 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   739   is an abbreviation for "of_nat :: nat => int". The simplification rules
   740   for "of_nat" have been changed to work like "int" did previously.
   741   (potential INCOMPATIBILITY)
   742   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   743   - of_nat_diff and of_nat_mult are no longer default simp rules
   744 
   745 * Method "algebra" solves polynomial equations over (semi)rings using
   746   Groebner bases. The (semi)ring structure is defined by locales and
   747   the tool setup depends on that generic context. Installing the
   748   method for a specific type involves instantiating the locale and
   749   possibly adding declarations for computation on the coefficients.
   750   The method is already instantiated for natural numbers and for the
   751   axiomatic class of idoms with numerals.  See also the paper by
   752   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   753   underlying this architecture of context-aware proof-tools.
   754 
   755 * constant "List.op @" now named "List.append".  Use ML antiquotations
   756 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   757 possible incompatibilities when working on ML level.
   758 
   759 * Constant renames due to introduction of canonical name prefixing for
   760   class package:
   761 
   762     HOL.abs ~> HOL.minus_class.abs
   763     HOL.divide ~> HOL.divide_class.divide
   764     Nat.power ~> Nat.power_class.power
   765     Nat.size ~> Nat.size_class.size
   766     Numeral.number_of ~> Numeral.number_class.number_of
   767     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   768 
   769 * Rudimentary class target mechanism involves constant renames:
   770 
   771     Orderings.min ~> Orderings.ord_class.min
   772     Orderings.max ~> Orderings.ord_class.max
   773     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   774 
   775 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   776 
   777 * new constant "undefined" with axiom "undefined x = undefined"
   778 
   779 * new class "default" with associated constant "default"
   780 
   781 * new function listsum :: 'a list => 'a for arbitrary monoids.
   782   Special syntax: "SUM x <- xs. f x" (and latex variants)
   783 
   784 * new (input only) syntax for Haskell-like list comprehension, eg
   785   [(x,y). x <- xs, y <- ys, x ~= y]
   786   For details see List.thy.
   787 
   788 * The special syntax for function "filter" has changed from [x : xs. P] to
   789   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   790   and for uniformity. INCOMPATIBILITY
   791 
   792 * Lemma "set_take_whileD" renamed to "set_takeWhileD"
   793 
   794 * New lemma collection field_simps (an extension of ring_simps)
   795   for manipulating (in)equations involving division. Multiplies
   796   with all denominators that can be proved to be non-zero (in equations)
   797   or positive/negative (in inequations).
   798 
   799 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   800   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   801   Removed lemmas field_xyz in Ring_and_Field
   802   because they were subsumed by lemmas xyz.
   803 INCOMPATIBILITY.
   804 
   805 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   806   when generating code.
   807 
   808 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   809   when generating code.
   810 
   811 * Library/Commutative_Ring.thy: switched from recdef to function package;
   812   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   813 
   814 * Some steps towards more uniform lattice theory development in HOL.
   815 
   816     constants "meet" and "join" now named "inf" and "sup"
   817     constant "Meet" now named "Inf"
   818 
   819     classes "meet_semilorder" and "join_semilorder" now named
   820       "lower_semilattice" and "upper_semilattice"
   821     class "lorder" now named "lattice"
   822     class "comp_lat" now named "complete_lattice"
   823 
   824     Instantiation of lattice classes allows explicit definitions
   825     for "inf" and "sup" operations.
   826 
   827   INCOMPATIBILITY.  Theorem renames:
   828 
   829     meet_left_le            ~> inf_le1
   830     meet_right_le           ~> inf_le2
   831     join_left_le            ~> sup_ge1
   832     join_right_le           ~> sup_ge2
   833     meet_join_le            ~> inf_sup_ord
   834     le_meetI                ~> le_infI
   835     join_leI                ~> le_supI
   836     le_meet                 ~> le_inf_iff
   837     le_join                 ~> ge_sup_conv
   838     meet_idempotent         ~> inf_idem
   839     join_idempotent         ~> sup_idem
   840     meet_comm               ~> inf_commute
   841     join_comm               ~> sup_commute
   842     meet_leI1               ~> le_infI1
   843     meet_leI2               ~> le_infI2
   844     le_joinI1               ~> le_supI1
   845     le_joinI2               ~> le_supI2
   846     meet_assoc              ~> inf_assoc
   847     join_assoc              ~> sup_assoc
   848     meet_left_comm          ~> inf_left_commute
   849     meet_left_idempotent    ~> inf_left_idem
   850     join_left_comm          ~> sup_left_commute
   851     join_left_idempotent    ~> sup_left_idem
   852     meet_aci                ~> inf_aci
   853     join_aci                ~> sup_aci
   854     le_def_meet             ~> le_iff_inf
   855     le_def_join             ~> le_iff_sup
   856     join_absorp2            ~> sup_absorb2
   857     join_absorp1            ~> sup_absorb1
   858     meet_absorp1            ~> inf_absorb1
   859     meet_absorp2            ~> inf_absorb2
   860     meet_join_absorp        ~> inf_sup_absorb
   861     join_meet_absorp        ~> sup_inf_absorb
   862     distrib_join_le         ~> distrib_sup_le
   863     distrib_meet_le         ~> distrib_inf_le
   864 
   865     add_meet_distrib_left   ~> add_inf_distrib_left
   866     add_join_distrib_left   ~> add_sup_distrib_left
   867     is_join_neg_meet        ~> is_join_neg_inf
   868     is_meet_neg_join        ~> is_meet_neg_sup
   869     add_meet_distrib_right  ~> add_inf_distrib_right
   870     add_join_distrib_right  ~> add_sup_distrib_right
   871     add_meet_join_distribs  ~> add_sup_inf_distribs
   872     join_eq_neg_meet        ~> sup_eq_neg_inf
   873     meet_eq_neg_join        ~> inf_eq_neg_sup
   874     add_eq_meet_join        ~> add_eq_inf_sup
   875     meet_0_imp_0            ~> inf_0_imp_0
   876     join_0_imp_0            ~> sup_0_imp_0
   877     meet_0_eq_0             ~> inf_0_eq_0
   878     join_0_eq_0             ~> sup_0_eq_0
   879     neg_meet_eq_join        ~> neg_inf_eq_sup
   880     neg_join_eq_meet        ~> neg_sup_eq_inf
   881     join_eq_if              ~> sup_eq_if
   882 
   883     mono_meet               ~> mono_inf
   884     mono_join               ~> mono_sup
   885     meet_bool_eq            ~> inf_bool_eq
   886     join_bool_eq            ~> sup_bool_eq
   887     meet_fun_eq             ~> inf_fun_eq
   888     join_fun_eq             ~> sup_fun_eq
   889     meet_set_eq             ~> inf_set_eq
   890     join_set_eq             ~> sup_set_eq
   891     meet1_iff               ~> inf1_iff
   892     meet2_iff               ~> inf2_iff
   893     meet1I                  ~> inf1I
   894     meet2I                  ~> inf2I
   895     meet1D1                 ~> inf1D1
   896     meet2D1                 ~> inf2D1
   897     meet1D2                 ~> inf1D2
   898     meet2D2                 ~> inf2D2
   899     meet1E                  ~> inf1E
   900     meet2E                  ~> inf2E
   901     join1_iff               ~> sup1_iff
   902     join2_iff               ~> sup2_iff
   903     join1I1                 ~> sup1I1
   904     join2I1                 ~> sup2I1
   905     join1I1                 ~> sup1I1
   906     join2I2                 ~> sup1I2
   907     join1CI                 ~> sup1CI
   908     join2CI                 ~> sup2CI
   909     join1E                  ~> sup1E
   910     join2E                  ~> sup2E
   911 
   912     is_meet_Meet            ~> is_meet_Inf
   913     Meet_bool_def           ~> Inf_bool_def
   914     Meet_fun_def            ~> Inf_fun_def
   915     Meet_greatest           ~> Inf_greatest
   916     Meet_lower              ~> Inf_lower
   917     Meet_set_def            ~> Inf_set_def
   918 
   919     listsp_meetI            ~> listsp_infI
   920     listsp_meet_eq          ~> listsp_inf_eq
   921 
   922     meet_min                ~> inf_min
   923     join_max                ~> sup_max
   924 
   925 * Classes "order" and "linorder": facts "refl", "trans" and
   926 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   927 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   928 
   929 * Classes "order" and "linorder": 
   930 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   931 proofs changed.
   932 
   933 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   934 INCOMPATIBILITY.
   935 
   936 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   937 INCOMPATIBILITY.
   938 
   939 * Added syntactic class "size"; overloaded constant "size" now has
   940 type "'a::size ==> bool"
   941 
   942 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   943 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   944 
   945 * Added method "lexicographic_order" automatically synthesizes
   946 termination relations as lexicographic combinations of size measures
   947 -- 'function' package.
   948 
   949 * HOL/records: generalised field-update to take a function on the
   950 field rather than the new value: r(|A := x|) is translated to A_update
   951 (K x) r The K-combinator that is internally used is called K_record.
   952 INCOMPATIBILITY: Usage of the plain update functions has to be
   953 adapted.
   954  
   955 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   956 0 * x = 0, which are required for a semiring.  Richer structures do
   957 not inherit from semiring_0 anymore, because this property is a
   958 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   959 semiring_0, there is more to prove, but this is mostly trivial.
   960 
   961 * axclass "recpower" was generalized to arbitrary monoids, not just
   962 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   963 commutativity or a semiring property, add the corresponding classes.
   964 
   965 * Unified locale partial_order with class definition (cf. theory
   966 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   967 
   968 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   969 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   970 Isar level, use abbreviations instead.
   971 
   972 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   973 rarely occuring name references (e.g. ``List.op mem.simps'') require
   974 renaming (e.g. ``List.memberl.simps'').
   975 
   976 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   977 INCOMPATIBILITY.
   978 
   979 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   980 
   981 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   982 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   983 significant changes for setting up numeral syntax for types:
   984 
   985   - new constants Numeral.pred and Numeral.succ instead
   986       of former Numeral.bin_pred and Numeral.bin_succ.
   987   - Use integer operations instead of bin_add, bin_mult and so on.
   988   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   989   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   990 
   991 See HOL/Integ/IntArith.thy for an example setup.
   992 
   993 * New top level command 'normal_form' computes the normal form of a
   994 term that may contain free variables. For example ``normal_form
   995 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   996 suitable for heavy-duty computations because the functions are
   997 compiled to ML first.
   998 
   999 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1000 25 like -->); output depends on the "iff" print_mode, the default is
  1001 "A = B" (with priority 50).
  1002 
  1003 * Renamed constants in HOL.thy and Orderings.thy:
  1004     op +   ~> HOL.plus_class.plus
  1005     op -   ~> HOL.minus_class.minus
  1006     uminus ~> HOL.minus_class.uminus
  1007     abs    ~> HOL.abs_class.abs
  1008     op *   ~> HOL.times_class.times
  1009     op <   ~> HOL.ord_class.less
  1010     op <=  ~> HOL.ord_class.less_eq
  1011 
  1012 Adaptions may be required in the following cases:
  1013 
  1014 a) User-defined constants using any of the names "plus", "minus", "times",
  1015 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
  1016 may go wrong.
  1017 INCOMPATIBILITY: use more specific names.
  1018 
  1019 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1020 INCOMPATIBILITY: use more specific names.
  1021 
  1022 c) Permutative equations (e.g. "a + b = b + a")
  1023 Since the change of names also changes the order of terms, permutative
  1024 rewrite rules may get applied in a different order. Experience shows that
  1025 this is rarely the case (only two adaptions in the whole Isabelle
  1026 distribution).
  1027 INCOMPATIBILITY: rewrite proofs
  1028 
  1029 d) ML code directly refering to constant names
  1030 This in general only affects hand-written proof tactics, simprocs and so on.
  1031 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
  1032 of const_name ML antiquotations.
  1033 
  1034 * Relations less (<) and less_eq (<=) are also available on type bool.
  1035 Modified syntax to disallow nesting without explicit parentheses,
  1036 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
  1037 
  1038 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1039 
  1040 * Relation composition operator "op O" now has precedence 75 and binds
  1041 stronger than union and intersection. INCOMPATIBILITY.
  1042 
  1043 * The old set interval syntax "{m..n(}" (and relatives) has been
  1044 removed.  Use "{m..<n}" (and relatives) instead.
  1045 
  1046 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1047 "t = s" to False (by simproc "neq_simproc").  For backward
  1048 compatibility this can be disabled by ML "reset use_neq_simproc".
  1049 
  1050 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1051 simp.
  1052 
  1053 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1054 
  1055 * Theorem setsum_mult renamed to setsum_right_distrib.
  1056 
  1057 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1058 ``rule'' method.
  1059 
  1060 * Reimplemented methods ``sat'' and ``satx'', with several
  1061 improvements: goals no longer need to be stated as "<prems> ==>
  1062 False", equivalences (i.e. "=" on type bool) are handled, variable
  1063 names of the form "lit_<n>" are no longer reserved, significant
  1064 speedup.
  1065 
  1066 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1067 zChaff is still supported as well.
  1068 
  1069 * 'inductive' and 'datatype': provide projections of mutual rules,
  1070 bundled as foo_bar.inducts;
  1071 
  1072 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1073 Library.
  1074 
  1075 * Library: moved theory Accessible_Part to main HOL.
  1076 
  1077 * Library: added theory Coinductive_List of potentially infinite lists
  1078 as greatest fixed-point.
  1079 
  1080 * Library: added theory AssocList which implements (finite) maps as
  1081 association lists.
  1082 
  1083 * Added proof method ``evaluation'' for efficiently solving a goal
  1084 (i.e. a boolean expression) by compiling it to ML. The goal is
  1085 "proved" (via an oracle) if it evaluates to True.
  1086 
  1087 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1088 also when invoked by the simplifier.  This results in the simplifier
  1089 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1090 fast_arith_split_limit to 0 to obtain the old behavior.
  1091 
  1092 * Support for hex (0x20) and binary (0b1001) numerals.
  1093 
  1094 * New method: reify eqs (t), where eqs are equations for an
  1095 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1096 parameter, computes a term s::'b and a list xs::'a list and proves the
  1097 theorem I xs s = t. This is also known as reification or quoting. The
  1098 resulting theorem is applied to the subgoal to substitute t with I xs
  1099 s.  If t is omitted, the subgoal itself is reified.
  1100 
  1101 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1102 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1103 where f is supposed to be a computable function (in the sense of code
  1104 generattion). The method uses reify to compute s and xs as above then
  1105 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1106 r and finally gets the theorem t = r, which is again applied to the
  1107 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1108 
  1109 * Reflection: Automatic reification now handels binding, an example
  1110 is available in HOL/ex/ReflectionEx.thy
  1111 
  1112 
  1113 *** HOL-Algebra ***
  1114 
  1115 * Formalisation of ideals and the quotient construction over rings.
  1116 
  1117 * Order and lattice theory no longer based on records.
  1118 INCOMPATIBILITY.
  1119 
  1120 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1121 greatest_closed.  INCOMPATIBILITY.
  1122 
  1123 * Method algebra is now set up via an attribute.  For examples see
  1124 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1125 of algebraic structures.
  1126 
  1127 * Renamed theory CRing to Ring.
  1128 
  1129 
  1130 *** HOL-Complex ***
  1131 
  1132 * Theory Real: new method ferrack implements quantifier elimination
  1133 for linear arithmetic over the reals. The quantifier elimination
  1134 feature is used only for decision, for compatibility with arith. This
  1135 means a goal is either solved or left unchanged, no simplification.
  1136 
  1137 * Hyperreal: Functions root and sqrt are now defined on negative real
  1138 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1139 Nonnegativity side conditions have been removed from many lemmas, so
  1140 that more subgoals may now be solved by simplification; potential
  1141 INCOMPATIBILITY.
  1142 
  1143 * Real: New axiomatic classes formalize real normed vector spaces and
  1144 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1145 and norm :: 'a => real.
  1146 
  1147 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1148 from reals into other types. The overloaded constant Reals :: 'a set
  1149 is now defined as range of_real; potential INCOMPATIBILITY.
  1150 
  1151 * Real: ML code generation is supported now and hence also quickcheck.
  1152 Reals are implemented as arbitrary precision rationals.
  1153 
  1154 * Hyperreal: Several constants that previously worked only for the
  1155 reals have been generalized, so they now work over arbitrary vector
  1156 spaces. Type annotations may need to be added in some cases; potential
  1157 INCOMPATIBILITY.
  1158 
  1159   Infinitesimal  :: ('a::real_normed_vector) star set
  1160   HFinite        :: ('a::real_normed_vector) star set
  1161   HInfinite      :: ('a::real_normed_vector) star set
  1162   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1163   monad          :: ('a::real_normed_vector) star => 'a star set
  1164   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1165   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1166   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1167   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1168   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1169   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1170   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1171   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1172   sgn            :: 'a::real_normed_vector => 'a
  1173   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1174 
  1175 * Complex: Some complex-specific constants are now abbreviations for
  1176 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1177 hnorm.  Other constants have been entirely removed in favor of the
  1178 polymorphic versions (INCOMPATIBILITY):
  1179 
  1180   approx        <-- capprox
  1181   HFinite       <-- CFinite
  1182   HInfinite     <-- CInfinite
  1183   Infinitesimal <-- CInfinitesimal
  1184   monad         <-- cmonad
  1185   galaxy        <-- cgalaxy
  1186   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1187   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1188   (ns)deriv     <-- (ns)cderiv
  1189 
  1190 
  1191 *** ML ***
  1192 
  1193 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1194 
  1195 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1196 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1197 init only required for impure data.  INCOMPATIBILITY: empty really
  1198 need to be empty (no dependencies on theory content!)
  1199 
  1200 * ML within Isar: antiquotations allow to embed statically-checked
  1201 formal entities in the source, referring to the context available at
  1202 compile-time.  For example:
  1203 
  1204 ML {* @{typ "'a => 'b"} *}
  1205 ML {* @{term "%x. x"} *}
  1206 ML {* @{prop "x == y"} *}
  1207 ML {* @{ctyp "'a => 'b"} *}
  1208 ML {* @{cterm "%x. x"} *}
  1209 ML {* @{cprop "x == y"} *}
  1210 ML {* @{thm asm_rl} *}
  1211 ML {* @{thms asm_rl} *}
  1212 ML {* @{const_name c} *}
  1213 ML {* @{const_syntax c} *}
  1214 ML {* @{context} *}
  1215 ML {* @{theory} *}
  1216 ML {* @{theory Pure} *}
  1217 ML {* @{simpset} *}
  1218 ML {* @{claset} *}
  1219 ML {* @{clasimpset} *}
  1220 
  1221 The same works for sources being ``used'' within an Isar context.
  1222 
  1223 * ML in Isar: improved error reporting; extra verbosity with
  1224 Toplevel.debug enabled.
  1225 
  1226 * Pure/library:
  1227 
  1228   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1229   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1230 
  1231 The semantics of "burrow" is: "take a function with *simulatanously*
  1232 transforms a list of value, and apply it *simulatanously* to a list of
  1233 list of values of the appropriate type". Compare this with "map" which
  1234 would *not* apply its argument function simulatanously but in
  1235 sequence; "fold_burrow" has an additional context.
  1236 
  1237 * Pure/library: functions map2 and fold2 with curried syntax for
  1238 simultanous mapping and folding:
  1239 
  1240     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1241     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1242 
  1243 * Pure/library: indexed lists - some functions in the Isabelle library
  1244 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1245 given more convenient names and signatures reminiscent of similar
  1246 functions for alists, tables, etc:
  1247 
  1248   val nth: 'a list -> int -> 'a 
  1249   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1250   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1251 
  1252 Note that fold_index starts counting at index 0, not 1 like foldln
  1253 used to.
  1254 
  1255 * Pure/library: added general ``divide_and_conquer'' combinator on
  1256 lists.
  1257 
  1258 * Pure/General/table.ML: the join operations now works via exceptions
  1259 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1260 admits slightly more efficient complex applications.
  1261 
  1262 * Pure: datatype Context.generic joins theory/Proof.context and
  1263 provides some facilities for code that works in either kind of
  1264 context, notably GenericDataFun for uniform theory and proof data.
  1265 
  1266 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1267 use Context.generic instead of just theory.
  1268 
  1269 * Pure: simplified internal attribute type, which is now always
  1270 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1271 vs. local (Proof.context) attributes have been discontinued, while
  1272 minimizing code duplication.  Thm.rule_attribute and
  1273 Thm.declaration_attribute build canonical attributes; see also
  1274 structure Context for further operations on Context.generic, notably
  1275 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1276 declarations and definitions.
  1277 
  1278 * Pure/kernel: consts certification ignores sort constraints given in
  1279 signature declarations.  (This information is not relevant to the
  1280 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1281 potential INCOMPATIBILITY.
  1282 
  1283 * Pure: axiomatic type classes are now purely definitional, with
  1284 explicit proofs of class axioms and super class relations performed
  1285 internally.  See Pure/axclass.ML for the main internal interfaces --
  1286 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1287 AxClass.axiomatize_class/classrel/arity supercede
  1288 Sign.add_classes/classrel/arities.
  1289 
  1290 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1291 global/local versions on theory vs. Proof.context have been
  1292 discontinued; Attrib.syntax and Method.syntax have been adapted
  1293 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1294 attributes, methods, etc.
  1295 
  1296 * Pure: several functions of signature "... -> theory -> theory * ..."
  1297 have been reoriented to "... -> theory -> ... * theory" in order to
  1298 allow natural usage in combination with the ||>, ||>>, |-> and
  1299 fold_map combinators.
  1300 
  1301 * Pure: official theorem names (closed derivations) and additional
  1302 comments (tags) are now strictly separate.  Name hints -- which are
  1303 maintained as tags -- may be attached any time without affecting the
  1304 derivation.
  1305 
  1306 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1307 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1308 achieve the old behaviour.
  1309 
  1310 * Pure: the "Goal" constant is now called "prop", supporting a
  1311 slightly more general idea of ``protecting'' meta-level rule
  1312 statements.
  1313 
  1314 * Pure: Logic.(un)varify only works in a global context, which is now
  1315 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1316 Logic.legacy_(un)varify as temporary workaround.
  1317 
  1318 * Pure: structure Name provides scalable operations for generating
  1319 internal variable names, notably Name.variants etc.  This replaces
  1320 some popular functions from term.ML:
  1321 
  1322   Term.variant		->  Name.variant
  1323   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1324   Term.invent_names	->  Name.invent_list
  1325 
  1326 Note that low-level renaming rarely occurs in new code -- operations
  1327 from structure Variable are used instead (see below).
  1328 
  1329 * Pure: structure Variable provides fundamental operations for proper
  1330 treatment of fixed/schematic variables in a context.  For example,
  1331 Variable.import introduces fixes for schematics of given facts and
  1332 Variable.export reverses the effect (up to renaming) -- this replaces
  1333 various freeze_thaw operations.
  1334 
  1335 * Pure: structure Goal provides simple interfaces for
  1336 init/conclude/finish and tactical prove operations (replacing former
  1337 Tactic.prove).  Goal.prove is the canonical way to prove results
  1338 within a given context; Goal.prove_global is a degraded version for
  1339 theory level goals, including a global Drule.standard.  Note that
  1340 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1341 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1342 in a locale context).
  1343 
  1344 * Isar: simplified treatment of user-level errors, using exception
  1345 ERROR of string uniformly.  Function error now merely raises ERROR,
  1346 without any side effect on output channels.  The Isar toplevel takes
  1347 care of proper display of ERROR exceptions.  ML code may use plain
  1348 handle/can/try; cat_error may be used to concatenate errors like this:
  1349 
  1350   ... handle ERROR msg => cat_error msg "..."
  1351 
  1352 Toplevel ML code (run directly or through the Isar toplevel) may be
  1353 embedded into the Isar toplevel with exception display/debug like
  1354 this:
  1355 
  1356   Isar.toplevel (fn () => ...)
  1357 
  1358 INCOMPATIBILITY, removed special transform_error facilities, removed
  1359 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1360 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1361 -- use plain ERROR instead.
  1362 
  1363 * Isar: theory setup now has type (theory -> theory), instead of a
  1364 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1365 
  1366 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1367 subject to ProofContext.debug/verbose flags.
  1368 
  1369 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1370 theory before entering a proof state.  Transactions now always see a
  1371 quasi-functional intermediate checkpoint, both in interactive and
  1372 batch mode.
  1373 
  1374 * Simplifier: the simpset of a running simplification process now
  1375 contains a proof context (cf. Simplifier.the_context), which is the
  1376 very context that the initial simpset has been retrieved from (by
  1377 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1378 (solver, looper etc.) may depend on arbitrary proof data.
  1379 
  1380 * Simplifier.inherit_context inherits the proof context (plus the
  1381 local bounds) of the current simplification process; any simproc
  1382 etc. that calls the Simplifier recursively should do this!  Removed
  1383 former Simplifier.inherit_bounds, which is already included here --
  1384 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1385 specify an explicit context using Simplifier.context/theory_context.
  1386 
  1387 * Simplifier/Classical Reasoner: more abstract interfaces
  1388 change_simpset/claset for modifying the simpset/claset reference of a
  1389 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1390 INCOMPATIBILITY.
  1391 
  1392 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1393 "Trueprop" etc.
  1394 
  1395 
  1396 *** System ***
  1397 
  1398 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1399 locations -- now includes the Isabelle version identifier as well.
  1400 This simplifies use of multiple Isabelle installations.
  1401 
  1402 * isabelle-process: option -S (secure mode) disables some critical
  1403 operations, notably runtime compilation and evaluation of ML source
  1404 code.
  1405 
  1406 
  1407 New in Isabelle2005 (October 2005)
  1408 ----------------------------------
  1409 
  1410 *** General ***
  1411 
  1412 * Theory headers: the new header syntax for Isar theories is
  1413 
  1414   theory <name>
  1415   imports <theory1> ... <theoryN>
  1416   uses <file1> ... <fileM>
  1417   begin
  1418 
  1419 where the 'uses' part is optional.  The previous syntax
  1420 
  1421   theory <name> = <theory1> + ... + <theoryN>:
  1422 
  1423 will disappear in the next release.  Use isatool fixheaders to convert
  1424 existing theory files.  Note that there is no change in ancient
  1425 non-Isar theories now, but these will disappear soon.
  1426 
  1427 * Theory loader: parent theories can now also be referred to via
  1428 relative and absolute paths.
  1429 
  1430 * Command 'find_theorems' searches for a list of criteria instead of a
  1431 list of constants. Known criteria are: intro, elim, dest, name:string,
  1432 simp:term, and any term. Criteria can be preceded by '-' to select
  1433 theorems that do not match. Intro, elim, dest select theorems that
  1434 match the current goal, name:s selects theorems whose fully qualified
  1435 name contain s, and simp:term selects all simplification rules whose
  1436 lhs match term.  Any other term is interpreted as pattern and selects
  1437 all theorems matching the pattern. Available in ProofGeneral under
  1438 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1439 
  1440   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1441 
  1442 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1443 matching the current goal as introduction rule and not having "HOL."
  1444 in their name (i.e. not being defined in theory HOL).
  1445 
  1446 * Command 'thms_containing' has been discontinued in favour of
  1447 'find_theorems'; INCOMPATIBILITY.
  1448 
  1449 * Communication with Proof General is now 8bit clean, which means that
  1450 Unicode text in UTF-8 encoding may be used within theory texts (both
  1451 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1452 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1453 
  1454   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1455   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1456 
  1457 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1458 Classical Reasoner.  Typical big applications run around 2 times
  1459 faster.
  1460 
  1461 
  1462 *** Document preparation ***
  1463 
  1464 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1465 of raw sources.  Only those symbols that do not require additional
  1466 LaTeX packages (depending on comments in isabellesym.sty) are
  1467 displayed properly, everything else is left verbatim.  isatool display
  1468 and isatool print are used as front ends (these are subject to the
  1469 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1470 
  1471 * Command tags control specific markup of certain regions of text,
  1472 notably folding and hiding.  Predefined tags include "theory" (for
  1473 theory begin and end), "proof" for proof commands, and "ML" for
  1474 commands involving ML code; the additional tags "visible" and
  1475 "invisible" are unused by default.  Users may give explicit tag
  1476 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1477 interpretation of tags is determined by the LaTeX job during document
  1478 preparation: see option -V of isatool usedir, or options -n and -t of
  1479 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1480 \isadroptag.
  1481 
  1482 Several document versions may be produced at the same time via isatool
  1483 usedir (the generated index.html will link all of them).  Typical
  1484 specifications include ''-V document=theory,proof,ML'' to present
  1485 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1486 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1487 these parts without any formal replacement text.  The Isabelle site
  1488 default settings produce ''document'' and ''outline'' versions as
  1489 specified above.
  1490 
  1491 * Several new antiquotations:
  1492 
  1493   @{term_type term} prints a term with its type annotated;
  1494 
  1495   @{typeof term} prints the type of a term;
  1496 
  1497   @{const const} is the same as @{term const}, but checks that the
  1498   argument is a known logical constant;
  1499 
  1500   @{term_style style term} and @{thm_style style thm} print a term or
  1501   theorem applying a "style" to it
  1502 
  1503   @{ML text}
  1504 
  1505 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1506 definitions, equations, inequations etc., 'concl' printing only the
  1507 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1508 to print the specified premise.  TermStyle.add_style provides an ML
  1509 interface for introducing further styles.  See also the "LaTeX Sugar"
  1510 document practical applications.  The ML antiquotation prints
  1511 type-checked ML expressions verbatim.
  1512 
  1513 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1514 and 'text' support optional locale specification '(in loc)', which
  1515 specifies the default context for interpreting antiquotations.  For
  1516 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1517 
  1518 * Option 'locale=NAME' of antiquotations specifies an alternative
  1519 context interpreting the subsequent argument.  For example: @{thm
  1520 [locale=lattice] inf_assoc}.
  1521 
  1522 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1523 a proof context.
  1524 
  1525 * Proper output of antiquotations for theory commands involving a
  1526 proof context (such as 'locale' or 'theorem (in loc) ...').
  1527 
  1528 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1529 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1530 
  1531 * isatool usedir: new option -C (default true) controls whether option
  1532 -D should include a copy of the original document directory; -C false
  1533 prevents unwanted effects such as copying of administrative CVS data.
  1534 
  1535 
  1536 *** Pure ***
  1537 
  1538 * Considerably improved version of 'constdefs' command.  Now performs
  1539 automatic type-inference of declared constants; additional support for
  1540 local structure declarations (cf. locales and HOL records), see also
  1541 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1542 sequential dependencies of definitions within a single 'constdefs'
  1543 section; moreover, the declared name needs to be an identifier.  If
  1544 all fails, consider to fall back on 'consts' and 'defs' separately.
  1545 
  1546 * Improved indexed syntax and implicit structures.  First of all,
  1547 indexed syntax provides a notational device for subscripted
  1548 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1549 expressions.  Secondly, in a local context with structure
  1550 declarations, number indexes \<^sub>n or the empty index (default
  1551 number 1) refer to a certain fixed variable implicitly; option
  1552 show_structs controls printing of implicit structures.  Typical
  1553 applications of these concepts involve record types and locales.
  1554 
  1555 * New command 'no_syntax' removes grammar declarations (and
  1556 translations) resulting from the given syntax specification, which is
  1557 interpreted in the same manner as for the 'syntax' command.
  1558 
  1559 * 'Advanced' translation functions (parse_translation etc.) may depend
  1560 on the signature of the theory context being presently used for
  1561 parsing/printing, see also isar-ref manual.
  1562 
  1563 * Improved 'oracle' command provides a type-safe interface to turn an
  1564 ML expression of type theory -> T -> term into a primitive rule of
  1565 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1566 is already included here); see also FOL/ex/IffExample.thy;
  1567 INCOMPATIBILITY.
  1568 
  1569 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1570 before); "cI" is no longer bound, use "c.intro" instead.
  1571 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1572 axclasses vs. locales.
  1573 
  1574 * Improved internal renaming of symbolic identifiers -- attach primes
  1575 instead of base 26 numbers.
  1576 
  1577 * New flag show_question_marks controls printing of leading question
  1578 marks in schematic variable names.
  1579 
  1580 * In schematic variable names, *any* symbol following \<^isub> or
  1581 \<^isup> is now treated as part of the base name.  For example, the
  1582 following works without printing of awkward ".0" indexes:
  1583 
  1584   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1585     by simp
  1586 
  1587 * Inner syntax includes (*(*nested*) comments*).
  1588 
  1589 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1590 annotations as "(00...)".
  1591 
  1592 * Clear separation of logical types and nonterminals, where the latter
  1593 may only occur in 'syntax' specifications or type abbreviations.
  1594 Before that distinction was only partially implemented via type class
  1595 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1596 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1597 exotic syntax specifications may require further adaption
  1598 (e.g. Cube/Cube.thy).
  1599 
  1600 * Removed obsolete type class "logic", use the top sort {} instead.
  1601 Note that non-logical types should be declared as 'nonterminals'
  1602 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1603 specifications.
  1604 
  1605 * Attributes 'induct' and 'cases': type or set names may now be
  1606 locally fixed variables as well.
  1607 
  1608 * Simplifier: can now control the depth to which conditional rewriting
  1609 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1610 Limit.
  1611 
  1612 * Simplifier: simplification procedures may now take the current
  1613 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1614 interface), which is very useful for calling the Simplifier
  1615 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1616 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1617 low-level mk_simproc no longer applies Logic.varify internally, to
  1618 allow for use in a context of fixed variables.
  1619 
  1620 * thin_tac now works even if the assumption being deleted contains !!
  1621 or ==>.  More generally, erule now works even if the major premise of
  1622 the elimination rule contains !! or ==>.
  1623 
  1624 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1625 
  1626 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1627 from Pure, which contains all common declarations already.  Both
  1628 theories are defined via plain Isabelle/Isar .thy files.
  1629 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1630 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1631 use isatool fixcpure to adapt your theory and ML sources.
  1632 
  1633 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1634 selections of theorems in named facts via index ranges.
  1635 
  1636 * 'print_theorems': in theory mode, really print the difference
  1637 wrt. the last state (works for interactive theory development only),
  1638 in proof mode print all local facts (cf. 'print_facts');
  1639 
  1640 * 'hide': option '(open)' hides only base names.
  1641 
  1642 * More efficient treatment of intermediate checkpoints in interactive
  1643 theory development.
  1644 
  1645 * Code generator is now invoked via code_module (incremental code
  1646 generation) and code_library (modular code generation, ML structures
  1647 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1648 must be quoted when used as identifiers.
  1649 
  1650 * New 'value' command for reading, evaluating and printing terms using
  1651 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1652 quoted when used as identifier.
  1653 
  1654 
  1655 *** Locales ***
  1656 
  1657 * New commands for the interpretation of locale expressions in
  1658 theories (1), locales (2) and proof contexts (3).  These generate
  1659 proof obligations from the expression specification.  After the
  1660 obligations have been discharged, theorems of the expression are added
  1661 to the theory, target locale or proof context.  The synopsis of the
  1662 commands is a follows:
  1663 
  1664   (1) interpretation expr inst
  1665   (2) interpretation target < expr
  1666   (3) interpret expr inst
  1667 
  1668 Interpretation in theories and proof contexts require a parameter
  1669 instantiation of terms from the current context.  This is applied to
  1670 specifications and theorems of the interpreted expression.
  1671 Interpretation in locales only permits parameter renaming through the
  1672 locale expression.  Interpretation is smart in that interpretations
  1673 that are active already do not occur in proof obligations, neither are
  1674 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1675 inspect active interpretations of a particular locale.  For details,
  1676 see the Isar Reference manual.  Examples can be found in
  1677 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1678 
  1679 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1680 'interpret' instead.
  1681 
  1682 * New context element 'constrains' for adding type constraints to
  1683 parameters.
  1684 
  1685 * Context expressions: renaming of parameters with syntax
  1686 redeclaration.
  1687 
  1688 * Locale declaration: 'includes' disallowed.
  1689 
  1690 * Proper static binding of attribute syntax -- i.e. types / terms /
  1691 facts mentioned as arguments are always those of the locale definition
  1692 context, independently of the context of later invocations.  Moreover,
  1693 locale operations (renaming and type / term instantiation) are applied
  1694 to attribute arguments as expected.
  1695 
  1696 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1697 actual attributes; rare situations may require Attrib.attribute to
  1698 embed those attributes into Attrib.src that lack concrete syntax.
  1699 Attribute implementations need to cooperate properly with the static
  1700 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1701 Attrib.XXX_thm etc. already do the right thing without further
  1702 intervention.  Only unusual applications -- such as "where" or "of"
  1703 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1704 on the context and the facts involved -- may have to assign parsed
  1705 values to argument tokens explicitly.
  1706 
  1707 * Changed parameter management in theorem generation for long goal
  1708 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1709 theorem statement in rare situations.
  1710 
  1711 * Locale inspection command 'print_locale' omits notes elements.  Use
  1712 'print_locale!' to have them included in the output.
  1713 
  1714 
  1715 *** Provers ***
  1716 
  1717 * Provers/hypsubst.ML: improved version of the subst method, for
  1718 single-step rewriting: it now works in bound variable contexts. New is
  1719 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1720 rewrite a different subterm than the original subst method, which is
  1721 still available as 'simplesubst'.
  1722 
  1723 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1724 and quasi orders.
  1725 
  1726 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1727 reflexive-transitive closure of relations.
  1728 
  1729 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1730 limit (previously hard-coded with a value of 20) user-definable.
  1731 
  1732 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1733 is peformed already.  Object-logics merely need to finish their
  1734 initial simpset configuration as before.  INCOMPATIBILITY.
  1735 
  1736 
  1737 *** HOL ***
  1738 
  1739 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1740 
  1741   syntax (epsilon)
  1742     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1743 
  1744 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1745 and x-symbol; use option '-m epsilon' to get it actually printed.
  1746 Moreover, the mathematically important symbolic identifier \<epsilon>
  1747 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1748 
  1749 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1750 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1751 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1752 support corresponding Isar calculations.
  1753 
  1754 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1755 instead of ":".
  1756 
  1757 * theory SetInterval: changed the syntax for open intervals:
  1758 
  1759   Old       New
  1760   {..n(}    {..<n}
  1761   {)n..}    {n<..}
  1762   {m..n(}   {m..<n}
  1763   {)m..n}   {m<..n}
  1764   {)m..n(}  {m<..<n}
  1765 
  1766 The old syntax is still supported but will disappear in the next
  1767 release.  For conversion use the following Emacs search and replace
  1768 patterns (these are not perfect but work quite well):
  1769 
  1770   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1771   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1772 
  1773 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1774 equalities in commutative rings; method 'algebra' provides a generic
  1775 interface.
  1776 
  1777 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1778 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1779 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1780 be a tuple pattern.
  1781 
  1782 Some new syntax forms are available:
  1783 
  1784   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1785   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1786   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1787   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1788 
  1789 The latter form "\<Sum>x < k. e" used to be based on a separate
  1790 function "Summation", which has been discontinued.
  1791 
  1792 * theory Finite_Set: in structured induction proofs, the insert case
  1793 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1794 (insert F x)'.
  1795 
  1796 * The 'refute' command has been extended to support a much larger
  1797 fragment of HOL, including axiomatic type classes, constdefs and
  1798 typedefs, inductive datatypes and recursion.
  1799 
  1800 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1801 Requires zChaff with proof generation to be installed.  See
  1802 HOL/ex/SAT_Examples.thy for examples.
  1803 
  1804 * Datatype induction via method 'induct' now preserves the name of the
  1805 induction variable. For example, when proving P(xs::'a list) by
  1806 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1807 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1808 in unstructured proof scripts.
  1809 
  1810 * Reworked implementation of records.  Improved scalability for
  1811 records with many fields, avoiding performance problems for type
  1812 inference. Records are no longer composed of nested field types, but
  1813 of nested extension types. Therefore the record type only grows linear
  1814 in the number of extensions and not in the number of fields.  The
  1815 top-level (users) view on records is preserved.  Potential
  1816 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1817 old record representation. The type generated for a record is called
  1818 <record_name>_ext_type.
  1819 
  1820 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1821 proofs triggered by a record definition or a simproc (if
  1822 quick_and_dirty is enabled).  Definitions of large records can take
  1823 quite long.
  1824 
  1825 New simproc record_upd_simproc for simplification of multiple record
  1826 updates enabled by default.  Moreover, trivial updates are also
  1827 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1828 occasionally, since simplification is more powerful by default.
  1829 
  1830 * typedef: proper support for polymorphic sets, which contain extra
  1831 type-variables in the term.
  1832 
  1833 * Simplifier: automatically reasons about transitivity chains
  1834 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1835 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1836 old proofs break occasionally as simplification may now solve more
  1837 goals than previously.
  1838 
  1839 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1840 present.  Works for all partial orders (class "order"), in particular
  1841 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1842 just like y <= x.
  1843 
  1844 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1845 bound variable or a constant then the let is unfolded.  Otherwise
  1846 first a is simplified to b, and then f b is simplified to g. If
  1847 possible we abstract b from g arriving at "let x = b in h x",
  1848 otherwise we unfold the let and arrive at g.  The simproc can be
  1849 enabled/disabled by the reference use_let_simproc.  Potential
  1850 INCOMPATIBILITY since simplification is more powerful by default.
  1851 
  1852 * Classical reasoning: the meson method now accepts theorems as arguments.
  1853 
  1854 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1855 jobs to provide advice on the provability of subgoals.
  1856 
  1857 * Theory OrderedGroup and Ring_and_Field: various additions and
  1858 improvements to faciliate calculations involving equalities and
  1859 inequalities.
  1860 
  1861 The following theorems have been eliminated or modified
  1862 (INCOMPATIBILITY):
  1863 
  1864   abs_eq             now named abs_of_nonneg
  1865   abs_of_ge_0        now named abs_of_nonneg
  1866   abs_minus_eq       now named abs_of_nonpos
  1867   imp_abs_id         now named abs_of_nonneg
  1868   imp_abs_neg_id     now named abs_of_nonpos
  1869   mult_pos           now named mult_pos_pos
  1870   mult_pos_le        now named mult_nonneg_nonneg
  1871   mult_pos_neg_le    now named mult_nonneg_nonpos
  1872   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1873   mult_neg           now named mult_neg_neg
  1874   mult_neg_le        now named mult_nonpos_nonpos
  1875 
  1876 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1877      
  1878      zero_le_square
  1879      not_square_less_zero 
  1880 
  1881   The following lemmas have been deleted from Real/RealPow:
  1882   
  1883      realpow_zero_zero
  1884      realpow_two
  1885      realpow_less
  1886      zero_le_power
  1887      realpow_two_le
  1888      abs_realpow_two
  1889      realpow_two_abs     
  1890 
  1891 * Theory Parity: added rules for simplifying exponents.
  1892 
  1893 * Theory List:
  1894 
  1895 The following theorems have been eliminated or modified
  1896 (INCOMPATIBILITY):
  1897 
  1898   list_all_Nil       now named list_all.simps(1)
  1899   list_all_Cons      now named list_all.simps(2)
  1900   list_all_conv      now named list_all_iff
  1901   set_mem_eq         now named mem_iff
  1902 
  1903 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1904 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1905 
  1906 
  1907 *** HOL-Complex ***
  1908 
  1909 * Theory RealDef: better support for embedding natural numbers and
  1910 integers in the reals.
  1911 
  1912 The following theorems have been eliminated or modified
  1913 (INCOMPATIBILITY):
  1914 
  1915   exp_ge_add_one_self  now requires no hypotheses
  1916   real_of_int_add      reversed direction of equality (use [symmetric])
  1917   real_of_int_minus    reversed direction of equality (use [symmetric])
  1918   real_of_int_diff     reversed direction of equality (use [symmetric])
  1919   real_of_int_mult     reversed direction of equality (use [symmetric])
  1920 
  1921 * Theory RComplete: expanded support for floor and ceiling functions.
  1922 
  1923 * Theory Ln is new, with properties of the natural logarithm
  1924 
  1925 * Hyperreal: There is a new type constructor "star" for making
  1926 nonstandard types.  The old type names are now type synonyms:
  1927 
  1928   hypreal = real star
  1929   hypnat = nat star
  1930   hcomplex = complex star
  1931 
  1932 * Hyperreal: Many groups of similarly-defined constants have been
  1933 replaced by polymorphic versions (INCOMPATIBILITY):
  1934 
  1935   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1936 
  1937   starset      <-- starsetNat, starsetC
  1938   *s*          <-- *sNat*, *sc*
  1939   starset_n    <-- starsetNat_n, starsetC_n
  1940   *sn*         <-- *sNatn*, *scn*
  1941   InternalSets <-- InternalNatSets, InternalCSets
  1942 
  1943   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1944   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1945   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1946   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1947   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1948 
  1949 * Hyperreal: Many type-specific theorems have been removed in favor of
  1950 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1951 
  1952   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1953   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1954   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1955   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1956   right_minus <-- hypreal_add_minus
  1957   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1958   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1959   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1960   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1961   mult_1_right <-- hcomplex_mult_one_right
  1962   mult_zero_left <-- hcomplex_mult_zero_left
  1963   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1964   right_distrib <-- hypnat_add_mult_distrib2
  1965   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1966   right_inverse <-- hypreal_mult_inverse
  1967   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1968   order_refl <-- {hypreal,hypnat}_le_refl
  1969   order_trans <-- {hypreal,hypnat}_le_trans
  1970   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1971   order_less_le <-- {hypreal,hypnat}_less_le
  1972   linorder_linear <-- {hypreal,hypnat}_le_linear
  1973   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1974   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1975   add_nonneg_nonneg <-- hypreal_le_add_order
  1976 
  1977 * Hyperreal: Separate theorems having to do with type-specific
  1978 versions of constants have been merged into theorems that apply to the
  1979 new polymorphic constants (INCOMPATIBILITY):
  1980 
  1981   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1982   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1983   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1984   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1985   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1986   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1987   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1988   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1989   STAR_diff <-- {STAR,STARC}_diff
  1990   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1991     STARC_hcomplex_of_complex}_image_subset
  1992   starset_n_Un <-- starset{Nat,C}_n_Un
  1993   starset_n_Int <-- starset{Nat,C}_n_Int
  1994   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1995   starset_n_diff <-- starset{Nat,C}_n_diff
  1996   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1997   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1998   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1999   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2000   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2001   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2002   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2003   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2004   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2005   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2006   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2007   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2008   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2009   starfun_diff <-- starfun{C,RC,CR}_diff
  2010   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2011   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2012   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2013   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2014   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2015   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2016   starfun_Id <-- starfunC_Id
  2017   starfun_approx <-- starfun{Nat,CR}_approx
  2018   starfun_capprox <-- starfun{C,RC}_capprox
  2019   starfun_abs <-- starfunNat_rabs
  2020   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2021   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2022   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2023   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2024   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2025   starfun_add_approx <-- starfunCR_add_approx
  2026   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2027   starfun_divide <-- starfun{C,CR,RC}_divide
  2028   starfun_n <-- starfun{Nat,C}_n
  2029   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2030   starfun_n_add <-- starfun{Nat,C}_n_add
  2031   starfun_n_add_minus <-- starfunNat_n_add_minus
  2032   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2033   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2034   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2035 
  2036   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2037   star_n_minus <-- {hypreal,hcomplex}_minus
  2038   star_n_diff <-- {hypreal,hcomplex}_diff
  2039   star_n_mult <-- {hypreal,hcomplex}_mult
  2040   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2041   star_n_le <-- {hypreal,hypnat}_le
  2042   star_n_less <-- {hypreal,hypnat}_less
  2043   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2044   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2045   star_n_abs <-- hypreal_hrabs
  2046   star_n_divide <-- hcomplex_divide
  2047 
  2048   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2049   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2050   star_of_diff <-- hypreal_of_real_diff
  2051   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2052   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2053   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2054   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2055   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2056   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2057   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2058   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2059   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2060   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2061   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2062   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2063   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2064   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2065   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2066   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2067   star_of_power <-- hypreal_of_real_power
  2068   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2069 
  2070 * Hyperreal: new method "transfer" that implements the transfer
  2071 principle of nonstandard analysis. With a subgoal that mentions
  2072 nonstandard types like "'a star", the command "apply transfer"
  2073 replaces it with an equivalent one that mentions only standard types.
  2074 To be successful, all free variables must have standard types; non-
  2075 standard variables must have explicit universal quantifiers.
  2076 
  2077 * Hyperreal: A theory of Taylor series.
  2078 
  2079 
  2080 *** HOLCF ***
  2081 
  2082 * Discontinued special version of 'constdefs' (which used to support
  2083 continuous functions) in favor of the general Pure one with full
  2084 type-inference.
  2085 
  2086 * New simplification procedure for solving continuity conditions; it
  2087 is much faster on terms with many nested lambda abstractions (cubic
  2088 instead of exponential time).
  2089 
  2090 * New syntax for domain package: selector names are now optional.
  2091 Parentheses should be omitted unless argument is lazy, for example:
  2092 
  2093   domain 'a stream = cons "'a" (lazy "'a stream")
  2094 
  2095 * New command 'fixrec' for defining recursive functions with pattern
  2096 matching; defining multiple functions with mutual recursion is also
  2097 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2098 sinr, or any data constructor defined by the domain package. The given
  2099 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2100 syntax and examples.
  2101 
  2102 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2103 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2104 but the proof obligation additionally includes an admissibility
  2105 requirement. The packages generate instances of class cpo or pcpo,
  2106 with continuity and strictness theorems for Rep and Abs.
  2107 
  2108 * HOLCF: Many theorems have been renamed according to a more standard naming
  2109 scheme (INCOMPATIBILITY):
  2110 
  2111   foo_inject:  "foo$x = foo$y ==> x = y"
  2112   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2113   foo_less:    "(foo$x << foo$y) = (x << y)"
  2114   foo_strict:  "foo$UU = UU"
  2115   foo_defined: "... ==> foo$x ~= UU"
  2116   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2117 
  2118 
  2119 *** ZF ***
  2120 
  2121 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2122 including the First Isomorphism Theorem (on quotienting by the kernel
  2123 of a homomorphism).
  2124 
  2125 * ZF/Simplifier: install second copy of type solver that actually
  2126 makes use of TC rules declared to Isar proof contexts (or locales);
  2127 the old version is still required for ML proof scripts.
  2128 
  2129 
  2130 *** Cube ***
  2131 
  2132 * Converted to Isar theory format; use locales instead of axiomatic
  2133 theories.
  2134 
  2135 
  2136 *** ML ***
  2137 
  2138 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2139 for ||>, ||>>, |>>,
  2140 
  2141 * Pure/library.ML no longer defines its own option datatype, but uses
  2142 that of the SML basis, which has constructors NONE and SOME instead of
  2143 None and Some, as well as exception Option.Option instead of OPTION.
  2144 The functions the, if_none, is_some, is_none have been adapted
  2145 accordingly, while Option.map replaces apsome.
  2146 
  2147 * Pure/library.ML: the exception LIST has been given up in favour of
  2148 the standard exceptions Empty and Subscript, as well as
  2149 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2150 superceded by the standard hd and tl functions etc.
  2151 
  2152 A number of basic list functions are no longer exported to the ML
  2153 toplevel, as they are variants of predefined functions.  The following
  2154 suggests how one can translate existing code:
  2155 
  2156     rev_append xs ys = List.revAppend (xs, ys)
  2157     nth_elem (i, xs) = List.nth (xs, i)
  2158     last_elem xs = List.last xs
  2159     flat xss = List.concat xss
  2160     seq fs = List.app fs
  2161     partition P xs = List.partition P xs
  2162     mapfilter f xs = List.mapPartial f xs
  2163 
  2164 * Pure/library.ML: several combinators for linear functional
  2165 transformations, notably reverse application and composition:
  2166 
  2167   x |> f                f #> g
  2168   (x, y) |-> f          f #-> g
  2169 
  2170 * Pure/library.ML: introduced/changed precedence of infix operators:
  2171 
  2172   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2173   infix 2 ?;
  2174   infix 3 o oo ooo oooo;
  2175   infix 4 ~~ upto downto;
  2176 
  2177 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2178 infix operators.
  2179 
  2180 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2181 fold_map support linear functional transformations and nesting.  For
  2182 example:
  2183 
  2184   fold f [x1, ..., xN] y =
  2185     y |> f x1 |> ... |> f xN
  2186 
  2187   (fold o fold) f [xs1, ..., xsN] y =
  2188     y |> fold f xs1 |> ... |> fold f xsN
  2189 
  2190   fold f [x1, ..., xN] =
  2191     f x1 #> ... #> f xN
  2192 
  2193   (fold o fold) f [xs1, ..., xsN] =
  2194     fold f xs1 #> ... #> fold f xsN
  2195 
  2196 * Pure/library.ML: the following selectors on type 'a option are
  2197 available:
  2198 
  2199   the:               'a option -> 'a  (*partial*)
  2200   these:             'a option -> 'a  where 'a = 'b list
  2201   the_default: 'a -> 'a option -> 'a
  2202   the_list:          'a option -> 'a list
  2203 
  2204 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2205 basic operations for association lists, following natural argument
  2206 order; moreover the explicit equality predicate passed here avoids
  2207 potentially expensive polymorphic runtime equality checks.
  2208 The old functions may be expressed as follows:
  2209 
  2210   assoc = uncurry (AList.lookup (op =))
  2211   assocs = these oo AList.lookup (op =)
  2212   overwrite = uncurry (AList.update (op =)) o swap
  2213 
  2214 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2215 
  2216   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2217   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2218 
  2219 replacing make_keylist and keyfilter (occassionally used)
  2220 Naive rewrites:
  2221 
  2222   make_keylist = AList.make
  2223   keyfilter = AList.find (op =)
  2224 
  2225 * eq_fst and eq_snd now take explicit equality parameter, thus
  2226   avoiding eqtypes. Naive rewrites:
  2227 
  2228     eq_fst = eq_fst (op =)
  2229     eq_snd = eq_snd (op =)
  2230 
  2231 * Removed deprecated apl and apr (rarely used).
  2232   Naive rewrites:
  2233 
  2234     apl (n, op) =>>= curry op n
  2235     apr (op, m) =>>= fn n => op (n, m)
  2236 
  2237 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2238 provides a reasonably efficient light-weight implementation of sets as
  2239 lists.
  2240 
  2241 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2242 few new operations; existing lookup and update are now curried to
  2243 follow natural argument order (for use with fold etc.);
  2244 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2245 
  2246 * Pure/General: output via the Isabelle channels of
  2247 writeln/warning/error etc. is now passed through Output.output, with a
  2248 hook for arbitrary transformations depending on the print_mode
  2249 (cf. Output.add_mode -- the first active mode that provides a output
  2250 function wins).  Already formatted output may be embedded into further
  2251 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2252 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2253 accommodate easy composition of diagnostic messages etc.  Programmers
  2254 rarely need to care about Output.output or Output.raw at all, with
  2255 some notable exceptions: Output.output is required when bypassing the
  2256 standard channels (writeln etc.), or in token translations to produce
  2257 properly formatted results; Output.raw is required when capturing
  2258 already output material that will eventually be presented to the user
  2259 a second time.  For the default print mode, both Output.output and
  2260 Output.raw have no effect.
  2261 
  2262 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2263 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2264 cumulative results are displayed at the end of a batch session.
  2265 
  2266 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2267 replaced by File.platform_path and File.shell_path (with appropriate
  2268 hooks).  This provides a clean interface for unusual systems where the
  2269 internal and external process view of file names are different.
  2270 
  2271 * Pure: more efficient orders for basic syntactic entities: added
  2272 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2273 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2274 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2275 orders now -- potential INCOMPATIBILITY for code that depends on a
  2276 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2277 Library.sort_strings on result).
  2278 
  2279 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2280 fold_types traverse types/terms from left to right, observing natural
  2281 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2282 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2283 
  2284 * Pure: name spaces have been refined, with significant changes of the
  2285 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2286 to extern(_table).  The plain name entry path is superceded by a
  2287 general 'naming' context, which also includes the 'policy' to produce
  2288 a fully qualified name and external accesses of a fully qualified
  2289 name; NameSpace.extend is superceded by context dependent
  2290 Sign.declare_name.  Several theory and proof context operations modify
  2291 the naming context.  Especially note Theory.restore_naming and
  2292 ProofContext.restore_naming to get back to a sane state; note that
  2293 Theory.add_path is no longer sufficient to recover from
  2294 Theory.absolute_path in particular.
  2295 
  2296 * Pure: new flags short_names (default false) and unique_names
  2297 (default true) for controlling output of qualified names.  If
  2298 short_names is set, names are printed unqualified.  If unique_names is
  2299 reset, the name prefix is reduced to the minimum required to achieve
  2300 the original result when interning again, even if there is an overlap
  2301 with earlier declarations.
  2302 
  2303 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2304 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2305 (useful for printing error messages).  INCOMPATIBILITY.
  2306 
  2307 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2308 Theory.theory are now identified, referring to the universal
  2309 Context.theory (see Pure/context.ML).  Actual signature and theory
  2310 content is managed as theory data.  The old code and interfaces were
  2311 spread over many files and structures; the new arrangement introduces
  2312 considerable INCOMPATIBILITY to gain more clarity:
  2313 
  2314   Context -- theory management operations (name, identity, inclusion,
  2315     parents, ancestors, merge, etc.), plus generic theory data;
  2316 
  2317   Sign -- logical signature and syntax operations (declaring consts,
  2318     types, etc.), plus certify/read for common entities;
  2319 
  2320   Theory -- logical theory operations (stating axioms, definitions,
  2321     oracles), plus a copy of logical signature operations (consts,
  2322     types, etc.); also a few basic management operations (Theory.copy,
  2323     Theory.merge, etc.)
  2324 
  2325 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2326 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2327 for convenience -- they merely return the theory.
  2328 
  2329 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2330 
  2331 * Pure: the Isar proof context type is already defined early in Pure
  2332 as Context.proof (note that ProofContext.context and Proof.context are
  2333 aliases, where the latter is the preferred name).  This enables other
  2334 Isabelle components to refer to that type even before Isar is present.
  2335 
  2336 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2337 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2338 any of these kinds.  For example, Sign.intern typeK is now
  2339 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2340 Theory.hide_types.  Also note that former
  2341 Theory.hide_classes/types/consts are now
  2342 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2343 internalize their arguments!  INCOMPATIBILITY.
  2344 
  2345 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2346 datatype thmref (with constructors Name and NameSelection) instead of
  2347 plain string -- INCOMPATIBILITY;
  2348 
  2349 * Pure: cases produced by proof methods specify options, where NONE
  2350 means to remove case bindings -- INCOMPATIBILITY in
  2351 (RAW_)METHOD_CASES.
  2352 
  2353 * Pure: the following operations retrieve axioms or theorems from a
  2354 theory node or theory hierarchy, respectively:
  2355 
  2356   Theory.axioms_of: theory -> (string * term) list
  2357   Theory.all_axioms_of: theory -> (string * term) list
  2358   PureThy.thms_of: theory -> (string * thm) list
  2359   PureThy.all_thms_of: theory -> (string * thm) list
  2360 
  2361 * Pure: print_tac now outputs the goal through the trace channel.
  2362 
  2363 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2364 Reference Toplevel.debug (default false) controls detailed printing
  2365 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2366 controls execution profiling -- set to 1 for time and 2 for space
  2367 (both increase the runtime).
  2368 
  2369 * Isar session: The initial use of ROOT.ML is now always timed,
  2370 i.e. the log will show the actual process times, in contrast to the
  2371 elapsed wall-clock time that the outer shell wrapper produces.
  2372 
  2373 * Simplifier: improved handling of bound variables (nameless
  2374 representation, avoid allocating new strings).  Simprocs that invoke
  2375 the Simplifier recursively should use Simplifier.inherit_bounds to
  2376 avoid local name clashes.  Failure to do so produces warnings
  2377 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2378 for further details.
  2379 
  2380 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2381 bindings for all theorems stored within a given theory; this may help
  2382 in porting non-Isar theories to Isar ones, while keeping ML proof
  2383 scripts for the time being.
  2384 
  2385 * ML operator HTML.with_charset specifies the charset begin used for
  2386 generated HTML files.  For example:
  2387 
  2388   HTML.with_charset "utf-8" use_thy "Hebrew";
  2389   HTML.with_charset "utf-8" use_thy "Chinese";
  2390 
  2391 
  2392 *** System ***
  2393 
  2394 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2395 isabelle, isatool etc.).
  2396 
  2397 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2398 isatool doc, isatool mkdir, display_drafts etc.).
  2399 
  2400 * isatool usedir: option -f allows specification of the ML file to be
  2401 used by Isabelle; default is ROOT.ML.
  2402 
  2403 * New isatool version outputs the version identifier of the Isabelle
  2404 distribution being used.
  2405 
  2406 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2407 (containing Boolean satisfiability problems) into Isabelle/HOL
  2408 theories.
  2409 
  2410 
  2411 
  2412 New in Isabelle2004 (April 2004)
  2413 --------------------------------
  2414 
  2415 *** General ***
  2416 
  2417 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2418   Replaces linorder.ML.
  2419 
  2420 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2421   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2422   (\<a>...\<z>), are now considered normal letters, and can therefore
  2423   be used anywhere where an ASCII letter (a...zA...Z) has until
  2424   now. COMPATIBILITY: This obviously changes the parsing of some
  2425   terms, especially where a symbol has been used as a binder, say
  2426   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2427   as an identifier.  Fix it by inserting a space around former
  2428   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2429   existing theory and ML files.
  2430 
  2431 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2432 
  2433 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2434   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2435   a normal (but invisible) letter. For multiple letter subscripts repeat
  2436   \<^isub> like this: x\<^isub>1\<^isub>2.
  2437 
  2438 * Pure: There are now sub-/superscripts that can span more than one
  2439   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2440   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2441   superscript. The new control characters are not identifier parts.
  2442 
  2443 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2444   content of "..." to the latex file instead of \isacntrl... . The "..."
  2445   may consist of any printable characters excluding the end bracket >.
  2446 
  2447 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2448   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2449   declare constants "final", which prevents their being given a definition
  2450   later.  It is useful for constants whose behaviour is fixed axiomatically
  2451   rather than definitionally, such as the meta-logic connectives.
  2452 
  2453 * Pure: 'instance' now handles general arities with general sorts
  2454   (i.e. intersections of classes),
  2455 
  2456 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2457   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2458   It can be changed to alter the colors/layout of generated pages.
  2459 
  2460 
  2461 *** Isar ***
  2462 
  2463 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2464   cut_tac, subgoal_tac and thin_tac:
  2465   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2466     locales are no longer forced to write Isar proof scripts.
  2467     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2468     emulations.
  2469   - INCOMPATIBILITY: names of variables to be instantiated may no
  2470     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2471     This is consistent with the instantiation attribute "where".
  2472 
  2473 * Attributes "where" and "of":
  2474   - Now take type variables of instantiated theorem into account when reading
  2475     the instantiation string.  This fixes a bug that caused instantiated
  2476     theorems to have too special types in some circumstances.
  2477   - "where" permits explicit instantiations of type variables.
  2478 
  2479 * Calculation commands "moreover" and "also" no longer interfere with
  2480   current facts ("this"), admitting arbitrary combinations with "then"
  2481   and derived forms.
  2482 
  2483 * Locales:
  2484   - Goal statements involving the context element "includes" no longer
  2485     generate theorems with internal delta predicates (those ending on
  2486     "_axioms") in the premise.
  2487     Resolve particular premise with <locale>.intro to obtain old form.
  2488   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2489     specification and "includes" elements in goal statement.
  2490   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2491     [intro?] and [elim?] (respectively) by default.
  2492   - Experimental command for instantiation of locales in proof contexts:
  2493         instantiate <label>[<attrs>]: <loc>
  2494     Instantiates locale <loc> and adds all its theorems to the current context
  2495     taking into account their attributes.  Label and attrs are optional
  2496     modifiers, like in theorem declarations.  If present, names of
  2497     instantiated theorems are qualified with <label>, and the attributes
  2498     <attrs> are applied after any attributes these theorems might have already.
  2499       If the locale has assumptions, a chained fact of the form
  2500     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2501     are derived.  The command does not support old-style locales declared
  2502     with "locale (open)".
  2503       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2504 
  2505 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2506   (Isar) contexts.
  2507 
  2508 
  2509 *** HOL ***
  2510 
  2511 * Proof import: new image HOL4 contains the imported library from
  2512   the HOL4 system with about 2500 theorems. It is imported by
  2513   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2514   can be used like any other Isabelle image.  See
  2515   HOL/Import/HOL/README for more information.
  2516 
  2517 * Simplifier:
  2518   - Much improved handling of linear and partial orders.
  2519     Reasoners for linear and partial orders are set up for type classes
  2520     "linorder" and "order" respectively, and are added to the default simpset
  2521     as solvers.  This means that the simplifier can build transitivity chains
  2522     to solve goals from the assumptions.
  2523   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2524     of blast or auto after simplification become unnecessary because the goal
  2525     is solved by simplification already.
  2526 
  2527 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2528     all proved in axiomatic type classes for semirings, rings and fields.
  2529 
  2530 * Numerics:
  2531   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2532     now formalized using the Ring_and_Field theory mentioned above.
  2533   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2534     than before, because now they are set up once in a generic manner.
  2535   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2536     Look for the general versions in Ring_and_Field (and Power if they concern
  2537     exponentiation).
  2538 
  2539 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2540 
  2541 * Records:
  2542   - Record types are now by default printed with their type abbreviation
  2543     instead of the list of all field types. This can be configured via
  2544     the reference "print_record_type_abbr".
  2545   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2546     (not enabled by default).
  2547   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2548     EX x. x = sel r to True (not enabled by default).
  2549   - Tactic "record_split_simp_tac" to split and simplify records added.
  2550 
  2551 * 'specification' command added, allowing for definition by
  2552   specification.  There is also an 'ax_specification' command that
  2553   introduces the new constants axiomatically.
  2554 
  2555 * arith(_tac) is now able to generate counterexamples for reals as well.
  2556 
  2557 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2558 
  2559 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2560   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2561 
  2562 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2563   matrix theory to linear programming.
  2564 
  2565 * Unions and Intersections:
  2566   The latex output syntax of UN and INT has been changed
  2567   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2568   i.e. the index formulae has become a subscript.
  2569   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2570 
  2571 * Unions and Intersections over Intervals:
  2572   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2573   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2574   like in normal math, and corresponding versions for < and for intersection.
  2575 
  2576 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2577   lexicographic dictonary ordering has been added as "lexord".
  2578 
  2579 * ML: the legacy theory structures Int and List have been removed. They had
  2580   conflicted with ML Basis Library structures having the same names.
  2581 
  2582 * 'refute' command added to search for (finite) countermodels.  Only works
  2583   for a fragment of HOL.  The installation of an external SAT solver is
  2584   highly recommended.  See "HOL/Refute.thy" for details.
  2585 
  2586 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2587   formulae under an assignment of free variables to random values.
  2588   In contrast to 'refute', it can deal with inductive datatypes,
  2589   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2590   for examples.
  2591 
  2592 
  2593 *** HOLCF ***
  2594 
  2595 * Streams now come with concatenation and are part of the HOLCF image
  2596 
  2597 
  2598 
  2599 New in Isabelle2003 (May 2003)
  2600 ------------------------------
  2601 
  2602 *** General ***
  2603 
  2604 * Provers/simplifier:
  2605 
  2606   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2607     Assumptions are now subject to complete mutual simplification,
  2608     not just from left to right. The simplifier now preserves
  2609     the order of assumptions.
  2610 
  2611     Potential INCOMPATIBILITY:
  2612 
  2613     -- simp sometimes diverges where the old version did
  2614        not, e.g. invoking simp on the goal
  2615 
  2616         [| P (f x); y = x; f x = f y |] ==> Q
  2617 
  2618        now gives rise to the infinite reduction sequence
  2619 
  2620         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2621 
  2622        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2623        kind of problem.
  2624 
  2625     -- Tactics combining classical reasoner and simplification (such as auto)
  2626        are also affected by this change, because many of them rely on
  2627        simp. They may sometimes diverge as well or yield a different numbers
  2628        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2629        in case of problems. Sometimes subsequent calls to the classical
  2630        reasoner will fail because a preceeding call to the simplifier too
  2631        eagerly simplified the goal, e.g. deleted redundant premises.
  2632 
  2633   - The simplifier trace now shows the names of the applied rewrite rules
  2634 
  2635   - You can limit the number of recursive invocations of the simplifier
  2636     during conditional rewriting (where the simplifie tries to solve the
  2637     conditions before applying the rewrite rule):
  2638     ML "simp_depth_limit := n"
  2639     where n is an integer. Thus you can force termination where previously
  2640     the simplifier would diverge.
  2641 
  2642   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2643 
  2644   - No longer aborts on failed congruence proof.  Instead, the
  2645     congruence is ignored.
  2646 
  2647 * Pure: New generic framework for extracting programs from constructive
  2648   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2649   as HOL/Extraction for some case studies.
  2650 
  2651 * Pure: The main goal of the proof state is no longer shown by default, only
  2652 the subgoals. This behaviour is controlled by a new flag.
  2653    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2654 (ML: Proof.show_main_goal).
  2655 
  2656 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2657 rules whose conclusion matches subgoal 1:
  2658       PG menu: Isabelle/Isar -> Show me -> matching rules
  2659 The rules are ordered by how closely they match the subgoal.
  2660 In particular, rules that solve a subgoal outright are displayed first
  2661 (or rather last, the way they are printed).
  2662 (ML: ProofGeneral.print_intros())
  2663 
  2664 * Pure: New flag trace_unify_fail causes unification to print
  2665 diagnostic information (PG: in trace buffer) when it fails. This is
  2666 useful for figuring out why single step proofs like rule, erule or
  2667 assumption failed.
  2668 
  2669 * Pure: Locale specifications now produce predicate definitions
  2670 according to the body of text (covering assumptions modulo local
  2671 definitions); predicate "loc_axioms" covers newly introduced text,
  2672 while "loc" is cumulative wrt. all included locale expressions; the
  2673 latter view is presented only on export into the global theory
  2674 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2675 on the old view without predicates;
  2676 
  2677 * Pure: predefined locales "var" and "struct" are useful for sharing
  2678 parameters (as in CASL, for example); just specify something like
  2679 ``var x + var y + struct M'' as import;
  2680 
  2681 * Pure: improved thms_containing: proper indexing of facts instead of
  2682 raw theorems; check validity of results wrt. current name space;
  2683 include local facts of proof configuration (also covers active
  2684 locales), cover fixed variables in index; may use "_" in term
  2685 specification; an optional limit for the number of printed facts may
  2686 be given (the default is 40);
  2687 
  2688 * Pure: disallow duplicate fact bindings within new-style theory files
  2689 (batch-mode only);
  2690 
  2691 * Provers: improved induct method: assumptions introduced by case
  2692 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2693 the goal statement); "foo" still refers to all facts collectively;
  2694 
  2695 * Provers: the function blast.overloaded has been removed: all constants
  2696 are regarded as potentially overloaded, which improves robustness in exchange
  2697 for slight decrease in efficiency;
  2698 
  2699 * Provers/linorder: New generic prover for transitivity reasoning over
  2700 linear orders.  Note: this prover is not efficient!
  2701 
  2702 * Isar: preview of problems to finish 'show' now produce an error
  2703 rather than just a warning (in interactive mode);
  2704 
  2705 
  2706 *** HOL ***
  2707 
  2708 * arith(_tac)
  2709 
  2710  - Produces a counter example if it cannot prove a goal.
  2711    Note that the counter example may be spurious if the goal is not a formula
  2712    of quantifier-free linear arithmetic.
  2713    In ProofGeneral the counter example appears in the trace buffer.
  2714 
  2715  - Knows about div k and mod k where k is a numeral of type nat or int.
  2716 
  2717  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2718    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2719    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2720 
  2721 * simp's arithmetic capabilities have been enhanced a bit: it now
  2722 takes ~= in premises into account (by performing a case split);
  2723 
  2724 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2725 are distributed over a sum of terms;
  2726 
  2727 * New tactic "trans_tac" and method "trans" instantiate
  2728 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2729 "<=", "<" and "=").
  2730 
  2731 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2732 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2733 
  2734 * 'typedef' command has new option "open" to suppress the set
  2735 definition;
  2736 
  2737 * functions Min and Max on finite sets have been introduced (theory
  2738 Finite_Set);
  2739 
  2740 * attribute [symmetric] now works for relations as well; it turns
  2741 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2742 
  2743 * induct over a !!-quantified statement (say !!x1..xn):
  2744   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2745 
  2746 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2747 %x. None. Warning: empty_def now refers to the previously hidden definition
  2748 of the empty set.
  2749 
  2750 * Algebra: formalization of classical algebra.  Intended as base for
  2751 any algebraic development in Isabelle.  Currently covers group theory
  2752 (up to Sylow's theorem) and ring theory (Universal Property of
  2753 Univariate Polynomials).  Contributions welcome;
  2754 
  2755 * GroupTheory: deleted, since its material has been moved to Algebra;
  2756 
  2757 * Complex: new directory of the complex numbers with numeric constants,
  2758 nonstandard complex numbers, and some complex analysis, standard and
  2759 nonstandard (Jacques Fleuriot);
  2760 
  2761 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2762 
  2763 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2764 Fleuriot);
  2765 
  2766 * Real/HahnBanach: updated and adapted to locales;
  2767 
  2768 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2769 Gray and Kramer);
  2770 
  2771 * UNITY: added the Meier-Sanders theory of progress sets;
  2772 
  2773 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2774 as abstract algorithms, instantiated to the JVM;
  2775 
  2776 * Bali: Java source language formalization. Type system, operational
  2777 semantics, axiomatic semantics. Supported language features:
  2778 classes, interfaces, objects,virtual methods, static methods,
  2779 static/instance fields, arrays, access modifiers, definite
  2780 assignment, exceptions.
  2781 
  2782 
  2783 *** ZF ***
  2784 
  2785 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2786 universe, etc.);
  2787 
  2788 * Main ZF: virtually all theories converted to new-style format;
  2789 
  2790 
  2791 *** ML ***
  2792 
  2793 * Pure: Tactic.prove provides sane interface for internal proofs;
  2794 omits the infamous "standard" operation, so this is more appropriate
  2795 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2796 
  2797 * Pure: improved error reporting of simprocs;
  2798 
  2799 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2800 up simprocs;
  2801 
  2802 
  2803 *** Document preparation ***
  2804 
  2805 * uses \par instead of \\ for line breaks in theory text. This may
  2806 shift some page breaks in large documents. To get the old behaviour
  2807 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2808 
  2809 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2810 other packages
  2811 
  2812 * \<euro> now needs package babel/greek instead of marvosym (which
  2813 broke \Rightarrow)
  2814 
  2815 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2816 textcomp package)
  2817 
  2818 
  2819 
  2820 New in Isabelle2002 (March 2002)
  2821 --------------------------------
  2822 
  2823 *** Document preparation ***
  2824 
  2825 * greatly simplified document preparation setup, including more
  2826 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2827 instructive isatool mkdir; users should basically be able to get
  2828 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2829 users may run a separate document processing stage manually like this:
  2830 "isatool usedir -D output HOL Test && isatool document Test/output";
  2831 
  2832 * theory dependency graph may now be incorporated into documents;
  2833 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2834 with \includegraphics of LaTeX;
  2835 
  2836 * proper spacing of consecutive markup elements, especially text
  2837 blocks after section headings;
  2838 
  2839 * support bold style (for single symbols only), input syntax is like
  2840 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2841 
  2842 * \<bullet> is now output as bold \cdot by default, which looks much
  2843 better in printed text;
  2844 
  2845 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2846 note that these symbols are currently unavailable in Proof General /
  2847 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2848 
  2849 * isatool latex no longer depends on changed TEXINPUTS, instead
  2850 isatool document copies the Isabelle style files to the target
  2851 location;
  2852 
  2853 
  2854 *** Isar ***
  2855 
  2856 * Pure/Provers: improved proof by cases and induction;
  2857   - 'case' command admits impromptu naming of parameters (such as
  2858     "case (Suc n)");
  2859   - 'induct' method divinates rule instantiation from the inductive
  2860     claim; no longer requires excessive ?P bindings for proper
  2861     instantiation of cases;
  2862   - 'induct' method properly enumerates all possibilities of set/type
  2863     rules; as a consequence facts may be also passed through *type*
  2864     rules without further ado;
  2865   - 'induct' method now derives symbolic cases from the *rulified*
  2866     rule (before it used to rulify cases stemming from the internal
  2867     atomized version); this means that the context of a non-atomic
  2868     statement becomes is included in the hypothesis, avoiding the
  2869     slightly cumbersome show "PROP ?case" form;
  2870   - 'induct' may now use elim-style induction rules without chaining
  2871     facts, using ``missing'' premises from the goal state; this allows
  2872     rules stemming from inductive sets to be applied in unstructured
  2873     scripts, while still benefitting from proper handling of non-atomic
  2874     statements; NB: major inductive premises need to be put first, all
  2875     the rest of the goal is passed through the induction;
  2876   - 'induct' proper support for mutual induction involving non-atomic
  2877     rule statements (uses the new concept of simultaneous goals, see
  2878     below);
  2879   - append all possible rule selections, but only use the first
  2880     success (no backtracking);
  2881   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2882   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2883   - added 'print_induct_rules' (covered by help item in recent Proof
  2884     General versions);
  2885   - moved induct/cases attributes to Pure, methods to Provers;
  2886   - generic method setup instantiated for FOL and HOL;
  2887 
  2888 * Pure: support multiple simultaneous goal statements, for example
  2889 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2890 meta-level mechanism, this acts as if several individual goals had
  2891 been stated separately; in particular common proof methods need to be
  2892 repeated in order to cover all claims; note that a single elimination
  2893 step is *not* sufficient to establish the two conjunctions, so this
  2894 fails:
  2895 
  2896   assume "A & B" then have A and B ..   (*".." fails*)
  2897 
  2898 better use "obtain" in situations as above; alternative refer to
  2899 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2900 
  2901 * Pure: proper integration with ``locales''; unlike the original
  2902 version by Florian Kammller, Isar locales package high-level proof
  2903 contexts rather than raw logical ones (e.g. we admit to include
  2904 attributes everywhere); operations on locales include merge and
  2905 rename; support for implicit arguments (``structures''); simultaneous
  2906 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2907 some examples;
  2908 
  2909 * Pure: the following commands have been ``localized'', supporting a
  2910 target locale specification "(in name)": 'lemma', 'theorem',
  2911 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2912 stored both within the locale and at the theory level (exported and
  2913 qualified by the locale name);
  2914 
  2915 * Pure: theory goals may now be specified in ``long'' form, with
  2916 ad-hoc contexts consisting of arbitrary locale elements. for example
  2917 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2918 definitions may be given, too); the result is a meta-level rule with
  2919 the context elements being discharged in the obvious way;
  2920 
  2921 * Pure: new proof command 'using' allows to augment currently used
  2922 facts after a goal statement ('using' is syntactically analogous to
  2923 'apply', but acts on the goal's facts only); this allows chained facts
  2924 to be separated into parts given before and after a claim, as in
  2925 ``from a and b have C using d and e <proof>'';
  2926 
  2927 * Pure: renamed "antecedent" case to "rule_context";
  2928 
  2929 * Pure: new 'judgment' command records explicit information about the
  2930 object-logic embedding (used by several tools internally); no longer
  2931 use hard-wired "Trueprop";
  2932 
  2933 * Pure: added 'corollary' command;
  2934 
  2935 * Pure: fixed 'token_translation' command;
  2936 
  2937 * Pure: removed obsolete 'exported' attribute;
  2938 
  2939 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2940 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2941 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2942 
  2943 * Pure: method 'atomize' presents local goal premises as object-level
  2944 statements (atomic meta-level propositions); setup controlled via
  2945 rewrite rules declarations of 'atomize' attribute; example
  2946 application: 'induct' method with proper rule statements in improper
  2947 proof *scripts*;
  2948 
  2949 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2950 now consider the syntactic context of assumptions, giving a better
  2951 chance to get type-inference of the arguments right (this is
  2952 especially important for locales);
  2953 
  2954 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2955 mode;
  2956 
  2957 * Pure/obtain: the formal conclusion "thesis", being marked as
  2958 ``internal'', may no longer be reference directly in the text;
  2959 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2960 situations;
  2961 
  2962 * Pure: generic 'sym' attribute which declares a rule both as pure
  2963 'elim?' and for the 'symmetric' operation;
  2964 
  2965 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2966 text; the fixed correlation with particular command syntax has been
  2967 discontinued;
  2968 
  2969 * Pure: new method 'rules' is particularly well-suited for proof
  2970 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2971 but often produces more compact proof terms with less detours;
  2972 
  2973 * Pure/Provers/classical: simplified integration with pure rule
  2974 attributes and methods; the classical "intro?/elim?/dest?"
  2975 declarations coincide with the pure ones; the "rule" method no longer
  2976 includes classically swapped intros; "intro" and "elim" methods no
  2977 longer pick rules from the context; also got rid of ML declarations
  2978 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2979 INCOMPATIBILITY;
  2980 
  2981 * Provers/classical: attribute 'swapped' produces classical inversions
  2982 of introduction rules;
  2983 
  2984 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2985 rules instead of full simplifier context; 'iff' attribute handles
  2986 conditional rules;
  2987 
  2988 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2989 
  2990 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2991 "(permissive)" option to recover old behavior;
  2992 
  2993 * HOL: 'inductive' no longer features separate (collective) attributes
  2994 for 'intros' (was found too confusing);
  2995 
  2996 * HOL: properly declared induction rules less_induct and
  2997 wf_induct_rule;
  2998 
  2999 
  3000 *** HOL ***
  3001 
  3002 * HOL: moved over to sane numeral syntax; the new policy is as
  3003 follows:
  3004 
  3005   - 0 and 1 are polymorphic constants, which are defined on any
  3006   numeric type (nat, int, real etc.);
  3007 
  3008   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3009   binary representation internally;
  3010 
  3011   - type nat has special constructor Suc, and generally prefers Suc 0
  3012   over 1::nat and Suc (Suc 0) over 2::nat;
  3013 
  3014 This change may cause significant problems of INCOMPATIBILITY; here
  3015 are some hints on converting existing sources:
  3016 
  3017   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3018   entities, so expressions involving "-" (unary or binary minus) need
  3019   to be spaced properly;
  3020 
  3021   - existing occurrences of "1" may need to be constraint "1::nat" or
  3022   even replaced by Suc 0; similar for old "2";
  3023 
  3024   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3025 
  3026   - remove all special provisions on numerals in proofs;
  3027 
  3028 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3029 representation (depends on bin_arith_simps in the default context);
  3030 
  3031 * HOL: symbolic syntax for x^2 (numeral 2);
  3032 
  3033 * HOL: the class of all HOL types is now called "type" rather than
  3034 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3035 in axclass/classes, instance/arities, and (usually rare) occurrences
  3036 in typings (of consts etc.); internally the class is called
  3037 "HOL.type", ML programs should refer to HOLogic.typeS;
  3038 
  3039 * HOL/record package improvements:
  3040   - new derived operations "fields" to build a partial record section,
  3041     "extend" to promote a fixed record to a record scheme, and
  3042     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3043     declared as simp by default;
  3044   - shared operations ("more", "fields", etc.) now need to be always
  3045     qualified) --- potential INCOMPATIBILITY;
  3046   - removed "make_scheme" operations (use "make" with "extend") --
  3047     INCOMPATIBILITY;
  3048   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3049   - provides cases/induct rules for use with corresponding Isar
  3050     methods (for concrete records, record schemes, concrete more
  3051     parts, and schematic more parts -- in that order);
  3052   - internal definitions directly based on a light-weight abstract
  3053     theory of product types over typedef rather than datatype;
  3054 
  3055 * HOL: generic code generator for generating executable ML code from
  3056 specifications; specific support for HOL constructs such as inductive
  3057 datatypes and sets, as well as recursive functions; can be invoked
  3058 via 'generate_code' theory section;
  3059 
  3060 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3061 
  3062 * HOL: consolidated and renamed several theories.  In particular:
  3063         Ord.thy has been absorbed into HOL.thy
  3064         String.thy has been absorbed into List.thy
  3065 
  3066 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3067 (beware of argument permutation!);
  3068 
  3069 * HOL: linorder_less_split superseded by linorder_cases;
  3070 
  3071 * HOL/List: "nodups" renamed to "distinct";
  3072 
  3073 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3074 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3075   - Ex_def has changed, now need to use some_eq_ex
  3076 
  3077 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3078 in this (rare) case use:
  3079 
  3080   delSWrapper "split_all_tac"
  3081   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3082 
  3083 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3084 MAY FAIL;
  3085 
  3086 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3087 Isabelle's type classes, ^ on functions and relations has too general
  3088 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3089 necessary to attach explicit type constraints;
  3090 
  3091 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3092 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3093 renamed accordingly (eg "compI" -> "rel_compI").
  3094 
  3095 * HOL: syntax translations now work properly with numerals and records
  3096 expressions;
  3097 
  3098 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3099 of "lam" -- INCOMPATIBILITY;
  3100 
  3101 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3102 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3103 renamed "Product_Type.unit";
  3104 
  3105 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3106 
  3107 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3108 the "cases" method);
  3109 
  3110 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3111 Florian Kammller);
  3112 
  3113 * HOL/IMP: updated and converted to new-style theory format; several
  3114 parts turned into readable document, with proper Isar proof texts and
  3115 some explanations (by Gerwin Klein);
  3116 
  3117 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3118 
  3119 * HOL-Hyperreal is now a logic image;
  3120 
  3121 
  3122 *** HOLCF ***
  3123 
  3124 * Isar: consts/constdefs supports mixfix syntax for continuous
  3125 operations;
  3126 
  3127 * Isar: domain package adapted to new-style theory format, e.g. see
  3128 HOLCF/ex/Dnat.thy;
  3129 
  3130 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3131 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3132 lift.induct_tac, always use UU instead of Undef;
  3133 
  3134 * HOLCF/IMP: updated and converted to new-style theory;
  3135 
  3136 
  3137 *** ZF ***
  3138 
  3139 * Isar: proper integration of logic-specific tools and packages,
  3140 including theory commands '(co)inductive', '(co)datatype',
  3141 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3142 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3143 
  3144 * theory Main no longer includes AC; for the Axiom of Choice, base
  3145 your theory on Main_ZFC;
  3146 
  3147 * the integer library now covers quotients and remainders, with many
  3148 laws relating division to addition, multiplication, etc.;
  3149 
  3150 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3151 typeless version of the formalism;
  3152 
  3153 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3154 format;
  3155 
  3156 * ZF/Induct: new directory for examples of inductive definitions,
  3157 including theory Multiset for multiset orderings; converted to
  3158 new-style theory format;
  3159 
  3160 * ZF: many new theorems about lists, ordinals, etc.;
  3161 
  3162 
  3163 *** General ***
  3164 
  3165 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3166 variable proof controls level of detail: 0 = no proofs (only oracle
  3167 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3168 also ref manual for further ML interfaces;
  3169 
  3170 * Pure/axclass: removed obsolete ML interface
  3171 goal_subclass/goal_arity;
  3172 
  3173 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3174 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3175 separate tokens, so expressions involving minus need to be spaced
  3176 properly;
  3177 
  3178 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3179 rather than "infixl" or "infixr";
  3180 
  3181 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3182 sort constraint specifications in type inference; e.g. "x::_::foo"
  3183 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3184 type variable);
  3185 
  3186 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3187 control output of nested => (types); the default behavior is
  3188 "type_brackets";
  3189 
  3190 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3191 tokens into AST constants;
  3192 
  3193 * Pure/syntax: prefer later declarations of translations and print
  3194 translation functions; potential INCOMPATIBILITY: need to reverse
  3195 multiple declarations for same syntax element constant;
  3196 
  3197 * Pure/show_hyps reset by default (in accordance to existing Isar
  3198 practice);
  3199 
  3200 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3201 addSafter;
  3202 
  3203 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3204 as well;
  3205 
  3206 * system: tested support for MacOS X; should be able to get Isabelle +
  3207 Proof General to work in a plain Terminal after installing Poly/ML
  3208 (e.g. from the Isabelle distribution area) and GNU bash alone
  3209 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3210 support requires further installations, e.g. from
  3211 http://fink.sourceforge.net/);
  3212 
  3213 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3214 
  3215 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3216 of 40 MB), cf. ML_OPTIONS;
  3217 
  3218 * system: Proof General keywords specification is now part of the
  3219 Isabelle distribution (see etc/isar-keywords.el);
  3220 
  3221 * system: support for persistent Proof General sessions (refrain from
  3222 outdating all loaded theories on startup); user may create writable
  3223 logic images like this: ``isabelle -q HOL Test'';
  3224 
  3225 * system: smart selection of Isabelle process versus Isabelle
  3226 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3227 run both "isabelle" and "Isabelle" even if file names are badly
  3228 damaged (executable inspects the case of the first letter of its own
  3229 name); added separate "isabelle-process" and "isabelle-interface";
  3230 
  3231 * system: refrain from any attempt at filtering input streams; no
  3232 longer support ``8bit'' encoding of old isabelle font, instead proper
  3233 iso-latin characters may now be used; the related isatools
  3234 "symbolinput" and "nonascii" have disappeared as well;
  3235 
  3236 * system: removed old "xterm" interface (the print modes "xterm" and
  3237 "xterm_color" are still available for direct use in a suitable
  3238 terminal);
  3239 
  3240 
  3241 
  3242 New in Isabelle99-2 (February 2001)
  3243 -----------------------------------
  3244 
  3245 *** Overview of INCOMPATIBILITIES ***
  3246 
  3247 * HOL: please note that theories in the Library and elsewhere often use the
  3248 new-style (Isar) format; to refer to their theorems in an ML script you must
  3249 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3250 
  3251 * HOL: inductive package no longer splits induction rule aggressively,
  3252 but only as far as specified by the introductions given; the old
  3253 format may be recovered via ML function complete_split_rule or attribute
  3254 'split_rule (complete)';
  3255 
  3256 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3257 gfp_Tarski to gfp_unfold;
  3258 
  3259 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3260 
  3261 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3262 relation); infix "^^" has been renamed "``"; infix "``" has been
  3263 renamed "`"; "univalent" has been renamed "single_valued";
  3264 
  3265 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3266 operation;
  3267 
  3268 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3269 
  3270 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3271 
  3272 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3273 consequence, it is no longer monotonic wrt. the local goal context
  3274 (which is now passed through the inductive cases);
  3275 
  3276 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3277 \<gg> to \<ggreater>;
  3278 
  3279 
  3280 *** Document preparation ***
  3281 
  3282 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3283 available: are "it" for near math-mode best-style output, "sl" for
  3284 slanted text style, and "tt" for plain type-writer; if no
  3285 \isabellestyle command is given, output is according to slanted
  3286 type-writer);
  3287 
  3288 * support sub/super scripts (for single symbols only), input syntax is
  3289 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3290 
  3291 * some more standard symbols; see Appendix A of the system manual for
  3292 the complete list of symbols defined in isabellesym.sty;
  3293 
  3294 * improved isabelle style files; more abstract symbol implementation
  3295 (should now use \isamath{...} and \isatext{...} in custom symbol
  3296 definitions);
  3297 
  3298 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3299 state; Note that presentation of goal states does not conform to
  3300 actual human-readable proof documents.  Please do not include goal
  3301 states into document output unless you really know what you are doing!
  3302 
  3303 * proper indentation of antiquoted output with proportional LaTeX
  3304 fonts;
  3305 
  3306 * no_document ML operator temporarily disables LaTeX document
  3307 generation;
  3308 
  3309 * isatool unsymbolize tunes sources for plain ASCII communication;
  3310 
  3311 
  3312 *** Isar ***
  3313 
  3314 * Pure: Isar now suffers initial goal statements to contain unbound
  3315 schematic variables (this does not conform to actual readable proof
  3316 documents, due to unpredictable outcome and non-compositional proof
  3317 checking); users who know what they are doing may use schematic goals
  3318 for Prolog-style synthesis of proven results;
  3319 
  3320 * Pure: assumption method (an implicit finishing) now handles actual
  3321 rules as well;
  3322 
  3323 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3324 initial goal, declare "that" only as Pure intro (only for single
  3325 steps); the "that" rule assumption may now be involved in implicit
  3326 finishing, thus ".." becomes a feasible for trivial obtains;
  3327 
  3328 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3329 instance proofs may be performed by "..";
  3330 
  3331 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3332 statements as well;
  3333 
  3334 * Pure: more robust selection of calculational rules;
  3335 
  3336 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3337 rule (as well as the assumption rule);
  3338 
  3339 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3340 lemmas, using the graph browser tool;
  3341 
  3342 * Pure: predict failure of "show" in interactive mode;
  3343 
  3344 * Pure: 'thms_containing' now takes actual terms as arguments;
  3345 
  3346 * HOL: improved method 'induct' --- now handles non-atomic goals
  3347 (potential INCOMPATIBILITY); tuned error handling;
  3348 
  3349 * HOL: cases and induct rules now provide explicit hints about the
  3350 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3351 any remaining facts are inserted into the goal verbatim;
  3352 
  3353 * HOL: local contexts (aka cases) may now contain term bindings as
  3354 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3355 the result to be shown in each case;
  3356 
  3357 * HOL: added 'recdef_tc' command;
  3358 
  3359 * isatool convert assists in eliminating legacy ML scripts;
  3360 
  3361 
  3362 *** HOL ***
  3363 
  3364 * HOL/Library: a collection of generic theories to be used together
  3365 with main HOL; the theory loader path already includes this directory
  3366 by default; the following existing theories have been moved here:
  3367 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3368 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3369 
  3370 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3371 modelling and verification task performed in Isabelle/HOL +
  3372 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3373 
  3374 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3375 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3376 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3377 'domain', this makes the theory consistent with mathematical
  3378 literature;
  3379 
  3380 * HOL basics: added overloaded operations "inverse" and "divide"
  3381 (infix "/"), syntax for generic "abs" operation, generic summation
  3382 operator \<Sum>;
  3383 
  3384 * HOL/typedef: simplified package, provide more useful rules (see also
  3385 HOL/subset.thy);
  3386 
  3387 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3388 now expressed as a proper nested rule (old-style tactic scripts may
  3389 require atomize_strip_tac to cope with non-atomic premises);
  3390 
  3391 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3392 to "split_conv" (old name still available for compatibility);
  3393 
  3394 * HOL: improved concrete syntax for strings (e.g. allows translation
  3395 rules with string literals);
  3396 
  3397 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3398  and Fleuriot's mechanization of analysis, including the transcendental
  3399  functions for the reals;
  3400 
  3401 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3402 
  3403 
  3404 *** CTT ***
  3405 
  3406 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3407 "lam" is displayed as TWO lambda-symbols
  3408 
  3409 * CTT: theory Main now available, containing everything (that is, Bool
  3410 and Arith);
  3411 
  3412 
  3413 *** General ***
  3414 
  3415 * Pure: the Simplifier has been implemented properly as a derived rule
  3416 outside of the actual kernel (at last!); the overall performance
  3417 penalty in practical applications is about 50%, while reliability of
  3418 the Isabelle inference kernel has been greatly improved;
  3419 
  3420 * print modes "brackets" and "no_brackets" control output of nested =>
  3421 (types) and ==> (props); the default behaviour is "brackets";
  3422 
  3423 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3424 as assumptions as well;
  3425 
  3426 * system: support Poly/ML 4.0;
  3427 
  3428 * system: isatool install handles KDE version 1 or 2;
  3429 
  3430 
  3431 
  3432 New in Isabelle99-1 (October 2000)
  3433 ----------------------------------
  3434 
  3435 *** Overview of INCOMPATIBILITIES ***
  3436 
  3437 * HOL: simplification of natural numbers is much changed; to partly
  3438 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3439 issue the following ML commands:
  3440 
  3441   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3442   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3443 
  3444 * HOL: simplification no longer dives into case-expressions; this is
  3445 controlled by "t.weak_case_cong" for each datatype t;
  3446 
  3447 * HOL: nat_less_induct renamed to less_induct;
  3448 
  3449 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3450 fixsome to patch .thy and .ML sources automatically;
  3451 
  3452   select_equality  -> some_equality
  3453   select_eq_Ex     -> some_eq_ex
  3454   selectI2EX       -> someI2_ex
  3455   selectI2         -> someI2
  3456   selectI          -> someI
  3457   select1_equality -> some1_equality
  3458   Eps_sym_eq       -> some_sym_eq_trivial
  3459   Eps_eq           -> some_eq_trivial
  3460 
  3461 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3462 
  3463 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3464 instead);
  3465 
  3466 * HOL: the recursion equations generated by 'recdef' are now called
  3467 f.simps instead of f.rules;
  3468 
  3469 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3470 
  3471 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3472 sometimes be needed;
  3473 
  3474 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3475 
  3476 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3477 
  3478 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3479 product is now "<*>" instead of "Times"; the lexicographic product is
  3480 now "<*lex*>" instead of "**";
  3481 
  3482 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3483 of main HOL, but was unused); better use HOL's datatype package;
  3484 
  3485 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3486 the old syntax may be recovered as follows:
  3487 
  3488   syntax (symbols)
  3489     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3490       (infixl "\\<oplus>" 100)
  3491 
  3492 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3493 
  3494 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3495 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3496 internally;
  3497 
  3498 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3499 changed from A/r to A//r;
  3500 
  3501 * ZF: new treatment of arithmetic (nat & int) may break some old
  3502 proofs;
  3503 
  3504 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3505 rulify -> rule_format, elimify -> elim_format, ...);
  3506 
  3507 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3508 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3509 should have to change intro!! to intro? only); replaced "delrule" by
  3510 "rule del";
  3511 
  3512 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3513 
  3514 * Provers: strengthened force_tac by using new first_best_tac;
  3515 
  3516 * LaTeX document preparation: several changes of isabelle.sty (see
  3517 lib/texinputs);
  3518 
  3519 
  3520 *** Document preparation ***
  3521 
  3522 * formal comments (text blocks etc.) in new-style theories may now
  3523 contain antiquotations of thm/prop/term/typ/text to be presented
  3524 according to latex print mode; concrete syntax is like this:
  3525 @{term[show_types] "f(x) = a + x"};
  3526 
  3527 * isatool mkdir provides easy setup of Isabelle session directories,
  3528 including proper document sources;
  3529 
  3530 * generated LaTeX sources are now deleted after successful run
  3531 (isatool document -c); may retain a copy somewhere else via -D option
  3532 of isatool usedir;
  3533 
  3534 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3535 style files, achieving self-contained LaTeX sources and simplifying
  3536 LaTeX debugging;
  3537 
  3538 * old-style theories now produce (crude) LaTeX output as well;
  3539 
  3540 * browser info session directories are now self-contained (may be put
  3541 on WWW server seperately); improved graphs of nested sessions; removed
  3542 graph for 'all sessions';
  3543 
  3544 * several improvements in isabelle style files; \isabellestyle{it}
  3545 produces fake math mode output; \isamarkupheader is now \section by
  3546 default; see lib/texinputs/isabelle.sty etc.;
  3547 
  3548 
  3549 *** Isar ***
  3550 
  3551 * Isar/Pure: local results and corresponding term bindings are now
  3552 subject to Hindley-Milner polymorphism (similar to ML); this
  3553 accommodates incremental type-inference very nicely;
  3554 
  3555 * Isar/Pure: new derived language element 'obtain' supports
  3556 generalized existence reasoning;
  3557 
  3558 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3559 support accumulation of results, without applying any rules yet;
  3560 useful to collect intermediate results without explicit name
  3561 references, and for use with transitivity rules with more than 2
  3562 premises;
  3563 
  3564 * Isar/Pure: scalable support for case-analysis type proofs: new
  3565 'case' language element refers to local contexts symbolically, as
  3566 produced by certain proof methods; internally, case names are attached
  3567 to theorems as "tags";
  3568 
  3569 * Isar/Pure: theory command 'hide' removes declarations from
  3570 class/type/const name spaces;
  3571 
  3572 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3573 indicate potential overloading;
  3574 
  3575 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3576 
  3577 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3578 "{a,b,c}" instead of {a,b,c};
  3579 
  3580 * Isar/Pure now provides its own version of intro/elim/dest
  3581 attributes; useful for building new logics, but beware of confusion
  3582 with the version in Provers/classical;
  3583 
  3584 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3585 case name 'antecedent';
  3586 
  3587 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3588 to the current context is now done automatically);
  3589 
  3590 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3591 for definining proof methods in ML;
  3592 
  3593 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3594 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3595 most cases, one should have to change intro!! to intro? only);
  3596 replaced "delrule" by "rule del";
  3597 
  3598 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3599 'symmetric' attribute (the latter supercedes [RS sym]);
  3600 
  3601 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3602 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3603 well (including splits);
  3604 
  3605 * Isar/Provers: Simplifier and Classical methods now support all kind
  3606 of modifiers used in the past, including 'cong', 'iff', etc.
  3607 
  3608 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3609 of Simplifier and Classical reasoner);
  3610 
  3611 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3612 now support named cases; major packages (inductive, datatype, primrec,
  3613 recdef) support case names and properly name parameters;
  3614 
  3615 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3616 monotonicity conditions are extracted to be proven at end of
  3617 calculations;
  3618 
  3619 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3620 method anyway;
  3621 
  3622 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3623 split_if split_if_asm; datatype package provides theorems foo.splits =
  3624 foo.split foo.split_asm for each datatype;
  3625 
  3626 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3627 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3628 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3629 use "(cases (simplified))" method in proper proof texts);
  3630 
  3631 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3632 
  3633 * Isar: names of theorems etc. may be natural numbers as well;
  3634 
  3635 * Isar: 'pr' command: optional arguments for goals_limit and
  3636 ProofContext.prems_limit; no longer prints theory contexts, but only
  3637 proof states;
  3638 
  3639 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3640 additional print modes to be specified; e.g. "pr(latex)" will print
  3641 proof state according to the Isabelle LaTeX style;
  3642 
  3643 * Isar: improved support for emulating tactic scripts, including proof
  3644 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3645 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3646 (for HOL datatypes);
  3647 
  3648 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3649 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3650 'proof method scripts' have to be in depth-first order;
  3651 
  3652 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3653 
  3654 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3655 should instead use individual commands for printing items
  3656 (print_commands, print_methods etc.);
  3657 
  3658 * Isar: added 'nothing' --- the empty list of theorems;
  3659 
  3660 
  3661 *** HOL ***
  3662 
  3663 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3664 corresponding virtual machine and a specification of its bytecode
  3665 verifier and a lightweight bytecode verifier, including proofs of
  3666 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3667 Cornelia Pusch (see also the homepage of project Bali at
  3668 http://isabelle.in.tum.de/Bali/);
  3669 
  3670 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3671 Clemens Ballarin;
  3672 
  3673 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3674 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3675 Rasmussen;
  3676 
  3677 * HOL/Lattice: fundamental concepts of lattice theory and order
  3678 structures, including duals, properties of bounds versus algebraic
  3679 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3680 Theorem for complete lattices etc.; may also serve as a demonstration
  3681 for abstract algebraic reasoning using axiomatic type classes, and
  3682 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3683 
  3684 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3685 von Oheimb;
  3686 
  3687 * HOL/IMPP: extension of IMP with local variables and mutually
  3688 recursive procedures, by David von Oheimb;
  3689 
  3690 * HOL/Lambda: converted into new-style theory and document;
  3691 
  3692 * HOL/ex/Multiquote: example of multiple nested quotations and
  3693 anti-quotations -- basically a generalized version of de-Bruijn
  3694 representation; very useful in avoiding lifting of operations;
  3695 
  3696 * HOL/record: added general record equality rule to simpset; fixed
  3697 select-update simplification procedure to handle extended records as
  3698 well; admit "r" as field name;
  3699 
  3700 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3701 other numeric types and also as the identity of groups, rings, etc.;
  3702 
  3703 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3704 Types nat and int belong to this axclass;
  3705 
  3706 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3707    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3708    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3709   two terms #m*u and #n*u are replaced by #(m+n)*u
  3710     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3711   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3712     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3713 
  3714 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3715 powerful prover for predicate logic but knows nothing of clasets; see
  3716 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3717 
  3718 * HOL: new version of "case_tac" subsumes both boolean case split and
  3719 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3720 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3721 
  3722 * HOL: simplification no longer dives into case-expressions: only the
  3723 selector expression is simplified, but not the remaining arms; to
  3724 enable full simplification of case-expressions for datatype t, you may
  3725 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3726 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3727 
  3728 * HOL/recdef: the recursion equations generated by 'recdef' for
  3729 function 'f' are now called f.simps instead of f.rules; if all
  3730 termination conditions are proved automatically, these simplification
  3731 rules are added to the simpset, as in primrec; rules may be named
  3732 individually as well, resulting in a separate list of theorems for
  3733 each equation;
  3734 
  3735 * HOL/While is a new theory that provides a while-combinator. It
  3736 permits the definition of tail-recursive functions without the
  3737 provision of a termination measure. The latter is necessary once the
  3738 invariant proof rule for while is applied.
  3739 
  3740 * HOL: new (overloaded) notation for the set of elements below/above
  3741 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3742 
  3743 * HOL: theorems impI, allI, ballI bound as "strip";
  3744 
  3745 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3746 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3747 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3748 
  3749 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3750 
  3751 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3752 main HOL, but was unused);
  3753 
  3754 * HOL: fewer consts declared as global (e.g. have to refer to
  3755 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3756 
  3757 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3758 in case of overlap with user translations (e.g. judgements over
  3759 tuples); (note that the underlying logical represenation is still
  3760 bogus);
  3761 
  3762 
  3763 *** ZF ***
  3764 
  3765 * ZF: simplification automatically cancels common terms in arithmetic
  3766 expressions over nat and int;
  3767 
  3768 * ZF: new treatment of nat to minimize type-checking: all operators
  3769 coerce their operands to a natural number using the function natify,
  3770 making the algebraic laws unconditional;
  3771 
  3772 * ZF: as above, for int: operators coerce their operands to an integer
  3773 using the function intify;
  3774 
  3775 * ZF: the integer library now contains many of the usual laws for the
  3776 orderings, including $<=, and monotonicity laws for $+ and $*;
  3777 
  3778 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3779 simplification;
  3780 
  3781 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3782 to the simplifier and classical reasoner simultaneously;
  3783 
  3784 
  3785 *** General ***
  3786 
  3787 * Provers: blast_tac now handles actual object-logic rules as
  3788 assumptions; note that auto_tac uses blast_tac internally as well;
  3789 
  3790 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3791 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3792 
  3793 * Provers: delrules now handles destruct rules as well (no longer need
  3794 explicit make_elim);
  3795 
  3796 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3797   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3798 use instead the strong form,
  3799   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3800 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3801 from destruct-rules;
  3802 
  3803 * Provers: Simplifier.easy_setup provides a fast path to basic
  3804 Simplifier setup for new object-logics;
  3805 
  3806 * Pure: AST translation rules no longer require constant head on LHS;
  3807 
  3808 * Pure: improved name spaces: ambiguous output is qualified; support
  3809 for hiding of names;
  3810 
  3811 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3812 XSYMBOL_HOME; no longer need to do manual configuration in most
  3813 situations;
  3814 
  3815 * system: compression of ML heaps images may now be controlled via -c
  3816 option of isabelle and isatool usedir (currently only observed by
  3817 Poly/ML);
  3818 
  3819 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3820 useful for remote X11);
  3821 
  3822 * system: provide TAGS file for Isabelle sources;
  3823 
  3824 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3825 order;
  3826 
  3827 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3828 timing flag supersedes proof_timing and Toplevel.trace;
  3829 
  3830 * ML: new combinators |>> and |>>> for incremental transformations
  3831 with secondary results (e.g. certain theory extensions):
  3832 
  3833 * ML: PureThy.add_defs gets additional argument to indicate potential
  3834 overloading (usually false);
  3835 
  3836 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3837 results;
  3838 
  3839 
  3840 
  3841 New in Isabelle99 (October 1999)
  3842 --------------------------------
  3843 
  3844 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3845 
  3846 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3847 are no longer simplified.  (This allows the simplifier to unfold recursive
  3848 functional programs.)  To restore the old behaviour, declare
  3849 
  3850     Delcongs [if_weak_cong];
  3851 
  3852 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3853 complement;
  3854 
  3855 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3856 
  3857 * HOL/datatype: mutual_induct_tac no longer exists --
  3858   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3859 
  3860 * HOL/typedef: fixed type inference for representing set; type
  3861 arguments now have to occur explicitly on the rhs as type constraints;
  3862 
  3863 * ZF: The con_defs part of an inductive definition may no longer refer
  3864 to constants declared in the same theory;
  3865 
  3866 * HOL, ZF: the function mk_cases, generated by the inductive
  3867 definition package, has lost an argument.  To simplify its result, it
  3868 uses the default simpset instead of a supplied list of theorems.
  3869 
  3870 * HOL/List: the constructors of type list are now Nil and Cons;
  3871 
  3872 * Simplifier: the type of the infix ML functions
  3873         setSSolver addSSolver setSolver addSolver
  3874 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3875 for packaging solvers. A solver is created via
  3876         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3877 where the string argument is only a comment.
  3878 
  3879 
  3880 *** Proof tools ***
  3881 
  3882 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3883 decision procedure for linear arithmetic. Currently it is used for
  3884 types `nat', `int', and `real' in HOL (see below); it can, should and
  3885 will be instantiated for other types and logics as well.
  3886 
  3887 * The simplifier now accepts rewrite rules with flexible heads, eg
  3888      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3889   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3890   matching.
  3891 
  3892 
  3893 *** General ***
  3894 
  3895 * New Isabelle/Isar subsystem provides an alternative to traditional
  3896 tactical theorem proving; together with the ProofGeneral/isar user
  3897 interface it offers an interactive environment for developing human
  3898 readable proof documents (Isar == Intelligible semi-automated
  3899 reasoning); for further information see isatool doc isar-ref,
  3900 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3901 
  3902 * improved and simplified presentation of theories: better HTML markup
  3903 (including colors), graph views in several sizes; isatool usedir now
  3904 provides a proper interface for user theories (via -P option); actual
  3905 document preparation based on (PDF)LaTeX is available as well (for
  3906 new-style theories only); see isatool doc system for more information;
  3907 
  3908 * native support for Proof General, both for classic Isabelle and
  3909 Isabelle/Isar;
  3910 
  3911 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3912 using the graph browser tool;
  3913 
  3914 * Isabelle manuals now also available as PDF;
  3915 
  3916 * theory loader rewritten from scratch (may not be fully
  3917 bug-compatible); old loadpath variable has been replaced by show_path,
  3918 add_path, del_path, reset_path functions; new operations such as
  3919 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3920 isatool doc ref);
  3921 
  3922 * improved isatool install: option -k creates KDE application icon,
  3923 option -p DIR installs standalone binaries;
  3924 
  3925 * added ML_PLATFORM setting (useful for cross-platform installations);
  3926 more robust handling of platform specific ML images for SML/NJ;
  3927 
  3928 * the settings environment is now statically scoped, i.e. it is never
  3929 created again in sub-processes invoked from isabelle, isatool, or
  3930 Isabelle;
  3931 
  3932 * path element specification '~~' refers to '$ISABELLE_HOME';
  3933 
  3934 * in locales, the "assumes" and "defines" parts may be omitted if
  3935 empty;
  3936 
  3937 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3938 long arrows);
  3939 
  3940 * new print_mode "HTML";
  3941 
  3942 * new flag show_tags controls display of tags of theorems (which are
  3943 basically just comments that may be attached by some tools);
  3944 
  3945 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3946 mode and goal output format:
  3947 
  3948 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3949 244c244
  3950 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3951 ---
  3952 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3953 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3954 181c181
  3955 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3956 ---
  3957 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3958 
  3959 * function bind_thms stores lists of theorems (cf. bind_thm);
  3960 
  3961 * new shorthand tactics ftac, eatac, datac, fatac;
  3962 
  3963 * qed (and friends) now accept "" as result name; in that case the
  3964 theorem is not stored, but proper checks and presentation of the
  3965 result still apply;
  3966 
  3967 * theorem database now also indexes constants "Trueprop", "all",
  3968 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3969 
  3970 
  3971 *** HOL ***
  3972 
  3973 ** HOL arithmetic **
  3974 
  3975 * There are now decision procedures for linear arithmetic over nat and
  3976 int:
  3977 
  3978 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3979 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3980 are treated as atomic; subformulae not involving type `nat' or `int'
  3981 are ignored; quantified subformulae are ignored unless they are
  3982 positive universal or negative existential. The tactic has to be
  3983 invoked by hand and can be a little bit slow. In particular, the
  3984 running time is exponential in the number of occurrences of `min' and
  3985 `max', and `-' on `nat'.
  3986 
  3987 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3988 (negated) (in)equalities among the premises and the conclusion into
  3989 account (i.e. no compound formulae) and does not know about `min' and
  3990 `max', and `-' on `nat'. It is fast and is used automatically by the
  3991 simplifier.
  3992 
  3993 NB: At the moment, these decision procedures do not cope with mixed
  3994 nat/int formulae where the two parts interact, such as `m < n ==>
  3995 int(m) < int(n)'.
  3996 
  3997 * HOL/Numeral provides a generic theory of numerals (encoded
  3998 efficiently as bit strings); setup for types nat/int/real is in place;
  3999 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4000 int, existing theories and proof scripts may require a few additional
  4001 type constraints;
  4002 
  4003 * integer division and remainder can now be performed on constant
  4004 arguments;
  4005 
  4006 * many properties of integer multiplication, division and remainder
  4007 are now available;
  4008 
  4009 * An interface to the Stanford Validity Checker (SVC) is available through the
  4010 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4011 are proved automatically.  SVC must be installed separately, and its results
  4012 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4013 invocation of the underlying oracle).  For SVC see
  4014   http://verify.stanford.edu/SVC
  4015 
  4016 * IsaMakefile: the HOL-Real target now builds an actual image;
  4017 
  4018 
  4019 ** HOL misc **
  4020 
  4021 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4022 (in Isabelle/Isar) -- by Gertrud Bauer;
  4023 
  4024 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4025 analysis for assembly languages with subtypes;
  4026 
  4027 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4028 -- avoids syntactic ambiguities and treats state, transition, and
  4029 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4030 changed syntax and (many) tactics;
  4031 
  4032 * HOL/inductive: Now also handles more general introduction rules such
  4033   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4034   theorems are now maintained within the theory (maintained via the
  4035   "mono" attribute);
  4036 
  4037 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4038   (using function types) such as
  4039 
  4040   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4041 
  4042 * HOL/record: record_simproc (part of the default simpset) takes care
  4043 of selectors applied to updated records; record_split_tac is no longer
  4044 part of the default claset; update_defs may now be removed from the
  4045 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4046 
  4047   claset_ref () := claset() addSWrapper record_split_wrapper;
  4048   Delsimprocs [record_simproc]
  4049 
  4050 * HOL/typedef: fixed type inference for representing set; type
  4051 arguments now have to occur explicitly on the rhs as type constraints;
  4052 
  4053 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4054 names rather than an ML expression;
  4055 
  4056 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4057 supplied later.  Program schemes can be defined, such as
  4058     "While B C s = (if B s then While B C (C s) else s)"
  4059 where the well-founded relation can be chosen after B and C have been given.
  4060 
  4061 * HOL/List: the constructors of type list are now Nil and Cons;
  4062 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4063 course, ML tools referring to List.list.op # etc. have to be adapted;
  4064 
  4065 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4066 disabled by default; run isabelle with option -m HOL to get back to
  4067 the original Gordon/HOL-style output;
  4068 
  4069 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4070 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4071 
  4072 * HOL basic syntax simplified (more orthogonal): all variants of
  4073 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4074 Eps operator is provided as well: "SOME x. P[x]";
  4075 
  4076 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4077 
  4078 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4079 thus available for user theories;
  4080 
  4081 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4082 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4083 time;
  4084 
  4085 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4086 several times and then mp;
  4087 
  4088 
  4089 *** LK ***
  4090 
  4091 * the notation <<...>> is now available as a notation for sequences of
  4092 formulas;
  4093 
  4094 * the simplifier is now installed
  4095 
  4096 * the axiom system has been generalized (thanks to Soren Heilmann)
  4097 
  4098 * the classical reasoner now has a default rule database
  4099 
  4100 
  4101 *** ZF ***
  4102 
  4103 * new primrec section allows primitive recursive functions to be given
  4104 directly (as in HOL) over datatypes and the natural numbers;
  4105 
  4106 * new tactics induct_tac and exhaust_tac for induction (or case
  4107 analysis) over datatypes and the natural numbers;
  4108 
  4109 * the datatype declaration of type T now defines the recursor T_rec;
  4110 
  4111 * simplification automatically does freeness reasoning for datatype
  4112 constructors;
  4113 
  4114 * automatic type-inference, with AddTCs command to insert new
  4115 type-checking rules;
  4116 
  4117 * datatype introduction rules are now added as Safe Introduction rules
  4118 to the claset;
  4119 
  4120 * the syntax "if P then x else y" is now available in addition to
  4121 if(P,x,y);
  4122 
  4123 
  4124 *** Internal programming interfaces ***
  4125 
  4126 * tuned simplifier trace output; new flag debug_simp;
  4127 
  4128 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4129 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4130 
  4131 * AxClass.axclass_tac lost the theory argument;
  4132 
  4133 * tuned current_goals_markers semantics: begin / end goal avoids
  4134 printing empty lines;
  4135 
  4136 * removed prs and prs_fn hook, which was broken because it did not
  4137 include \n in its semantics, forcing writeln to add one
  4138 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4139 string -> unit if you really want to output text without newline;
  4140 
  4141 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4142 plain output, interface builders may have to enable 'isabelle_font'
  4143 mode to get Isabelle font glyphs as before;
  4144 
  4145 * refined token_translation interface; INCOMPATIBILITY: output length
  4146 now of type real instead of int;
  4147 
  4148 * theory loader actions may be traced via new ThyInfo.add_hook
  4149 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4150 your own database of information attached to *whole* theories -- as
  4151 opposed to intra-theory data slots offered via TheoryDataFun;
  4152 
  4153 * proper handling of dangling sort hypotheses (at last!);
  4154 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4155 extra sort hypotheses that can be witnessed from the type signature;
  4156 the force_strip_shyps flag is gone, any remaining shyps are simply
  4157 left in the theorem (with a warning issued by strip_shyps_warning);
  4158 
  4159 
  4160 
  4161 New in Isabelle98-1 (October 1998)
  4162 ----------------------------------
  4163 
  4164 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4165 
  4166 * several changes of automated proof tools;
  4167 
  4168 * HOL: major changes to the inductive and datatype packages, including
  4169 some minor incompatibilities of theory syntax;
  4170 
  4171 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4172 called `inj_on';
  4173 
  4174 * HOL: removed duplicate thms in Arith:
  4175   less_imp_add_less  should be replaced by  trans_less_add1
  4176   le_imp_add_le      should be replaced by  trans_le_add1
  4177 
  4178 * HOL: unary minus is now overloaded (new type constraints may be
  4179 required);
  4180 
  4181 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4182 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4183 now taken as an integer constant.
  4184 
  4185 * Pure: ML function 'theory_of' renamed to 'theory';
  4186 
  4187 
  4188 *** Proof tools ***
  4189 
  4190 * Simplifier:
  4191   1. Asm_full_simp_tac is now more aggressive.
  4192      1. It will sometimes reorient premises if that increases their power to
  4193         simplify.
  4194      2. It does no longer proceed strictly from left to right but may also
  4195         rotate premises to achieve further simplification.
  4196      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4197      old Asm_full_simp_tac in that it does not rotate premises.
  4198   2. The simplifier now knows a little bit about nat-arithmetic.
  4199 
  4200 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4201 allows for selected deletion of wrappers, by introduction of names for
  4202 wrapper functionals.  This implies that addbefore, addSbefore,
  4203 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4204 and that adding two tactics with the same name overwrites the first
  4205 one (emitting a warning).
  4206   type wrapper = (int -> tactic) -> (int -> tactic)
  4207   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4208   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4209   delWrapper, delSWrapper: claset *  string            -> claset
  4210   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4211 
  4212 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4213 semantics; addbefore now affects only the unsafe part of step_tac
  4214 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4215 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4216 by Force_tac;
  4217 
  4218 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4219 compWrapper; added safe wrapper (and access functions for it);
  4220 
  4221 * HOL/split_all_tac is now much faster and fails if there is nothing
  4222 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4223 and the names of the automatically generated variables have changed.
  4224 split_all_tac has moved within claset() from unsafe wrappers to safe
  4225 wrappers, which means that !!-bound variables are split much more
  4226 aggressively, and safe_tac and clarify_tac now split such variables.
  4227 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4228 Note: the same holds for record_split_tac, which does the job of
  4229 split_all_tac for record fields.
  4230 
  4231 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4232 permanently to the default simpset using Addsplits just like
  4233 Addsimps. They can be removed via Delsplits just like
  4234 Delsimps. Lower-case versions are also available.
  4235 
  4236 * HOL/Simplifier: The rule split_if is now part of the default
  4237 simpset. This means that the simplifier will eliminate all occurrences
  4238 of if-then-else in the conclusion of a goal. To prevent this, you can
  4239 either remove split_if completely from the default simpset by
  4240 `Delsplits [split_if]' or remove it in a specific call of the
  4241 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4242 other case splitting rules to/from the default simpset: every datatype
  4243 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4244 t is the name of the datatype).
  4245 
  4246 * Classical reasoner / Simplifier combination: new force_tac (and
  4247 derivatives Force_tac, force) combines rewriting and classical
  4248 reasoning (and whatever other tools) similarly to auto_tac, but is
  4249 aimed to solve the given subgoal completely.
  4250 
  4251 
  4252 *** General ***
  4253 
  4254 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4255 and `goalw': the theory is no longer needed as an explicit argument -
  4256 the current theory context is used; assumptions are no longer returned
  4257 at the ML-level unless one of them starts with ==> or !!; it is
  4258 recommended to convert to these new commands using isatool fixgoal
  4259 (backup your sources first!);
  4260 
  4261 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4262 the current theory context, and 'theory' to lookup stored theories;
  4263 
  4264 * new theory section 'locale' for declaring constants, assumptions and
  4265 definitions that have local scope;
  4266 
  4267 * new theory section 'nonterminals' for purely syntactic types;
  4268 
  4269 * new theory section 'setup' for generic ML setup functions
  4270 (e.g. package initialization);
  4271 
  4272 * the distribution now includes Isabelle icons: see
  4273 lib/logo/isabelle-{small,tiny}.xpm;
  4274 
  4275 * isatool install - install binaries with absolute references to
  4276 ISABELLE_HOME/bin;
  4277 
  4278 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4279 
  4280 * print mode 'emacs' reserved for Isamode;
  4281 
  4282 * support multiple print (ast) translations per constant name;
  4283 
  4284 * theorems involving oracles are now printed with a suffixed [!];
  4285 
  4286 
  4287 *** HOL ***
  4288 
  4289 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4290 
  4291 * HOL/inductive package reorganized and improved: now supports mutual
  4292 definitions such as
  4293 
  4294   inductive EVEN ODD
  4295     intrs
  4296       null "0 : EVEN"
  4297       oddI "n : EVEN ==> Suc n : ODD"
  4298       evenI "n : ODD ==> Suc n : EVEN"
  4299 
  4300 new theorem list "elims" contains an elimination rule for each of the
  4301 recursive sets; inductive definitions now handle disjunctive premises
  4302 correctly (also ZF);
  4303 
  4304 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4305 "mutual_induct" no longer exists - the induction rule is always
  4306 contained in "induct";
  4307 
  4308 
  4309 * HOL/datatype package re-implemented and greatly improved: now
  4310 supports mutually recursive datatypes such as
  4311 
  4312   datatype
  4313     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4314             | SUM ('a aexp) ('a aexp)
  4315             | DIFF ('a aexp) ('a aexp)
  4316             | NUM 'a
  4317   and
  4318     'a bexp = LESS ('a aexp) ('a aexp)
  4319             | AND ('a bexp) ('a bexp)
  4320             | OR ('a bexp) ('a bexp)
  4321 
  4322 as well as indirectly recursive datatypes such as
  4323 
  4324   datatype
  4325     ('a, 'b) term = Var 'a
  4326                   | App 'b ((('a, 'b) term) list)
  4327 
  4328 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4329 induction on mutually / indirectly recursive datatypes.
  4330 
  4331 Primrec equations are now stored in theory and can be accessed via
  4332 <function_name>.simps.
  4333 
  4334 INCOMPATIBILITIES:
  4335 
  4336   - Theories using datatypes must now have theory Datatype as an
  4337     ancestor.
  4338   - The specific <typename>.induct_tac no longer exists - use the
  4339     generic induct_tac instead.
  4340   - natE has been renamed to nat.exhaust - use exhaust_tac
  4341     instead of res_inst_tac ... natE. Note that the variable
  4342     names in nat.exhaust differ from the names in natE, this
  4343     may cause some "fragile" proofs to fail.
  4344   - The theorems split_<typename>_case and split_<typename>_case_asm
  4345     have been renamed to <typename>.split and <typename>.split_asm.
  4346   - Since default sorts of type variables are now handled correctly,
  4347     some datatype definitions may have to be annotated with explicit
  4348     sort constraints.
  4349   - Primrec definitions no longer require function name and type
  4350     of recursive argument.
  4351 
  4352 Consider using isatool fixdatatype to adapt your theories and proof
  4353 scripts to the new package (backup your sources first!).
  4354 
  4355 
  4356 * HOL/record package: considerably improved implementation; now
  4357 includes concrete syntax for record types, terms, updates; theorems
  4358 for surjective pairing and splitting !!-bound record variables; proof
  4359 support is as follows:
  4360 
  4361   1) standard conversions (selectors or updates applied to record
  4362 constructor terms) are part of the standard simpset;
  4363 
  4364   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4365 made part of standard simpset and claset via addIffs;
  4366 
  4367   3) a tactic for record field splitting (record_split_tac) is part of
  4368 the standard claset (addSWrapper);
  4369 
  4370 To get a better idea about these rules you may retrieve them via
  4371 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4372 the name of your record type.
  4373 
  4374 The split tactic 3) conceptually simplifies by the following rule:
  4375 
  4376   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4377 
  4378 Thus any record variable that is bound by meta-all will automatically
  4379 blow up into some record constructor term, consequently the
  4380 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4381 solve record problems automatically.
  4382 
  4383 
  4384 * reorganized the main HOL image: HOL/Integ and String loaded by
  4385 default; theory Main includes everything;
  4386 
  4387 * automatic simplification of integer sums and comparisons, using cancellation;
  4388 
  4389 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4390 
  4391 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4392 
  4393 * many new identities for unions, intersections, set difference, etc.;
  4394 
  4395 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4396 called split_if, split_split, split_sum_case and split_nat_case (to go
  4397 with add/delsplits);
  4398 
  4399 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4400 (?x::unit) = (); this is made part of the default simpset, which COULD
  4401 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4402 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4403 unit_abs_eta_conv is added in order to counter the effect of
  4404 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4405 %u.f();
  4406 
  4407 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4408 makes more sense);
  4409 
  4410 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4411   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4412   disjointness reasoning but breaking a few old proofs.
  4413 
  4414 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4415 to 'converse' from 'inverse' (for compatibility with ZF and some
  4416 literature);
  4417 
  4418 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4419 the well-founded relation;
  4420 
  4421 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4422     Compl A.  The "Compl" syntax remains available as input syntax for this
  4423     release ONLY.
  4424 
  4425 * HOL/Update: new theory of function updates:
  4426     f(a:=b) == %x. if x=a then b else f x
  4427 may also be iterated as in f(a:=b,c:=d,...);
  4428 
  4429 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4430 
  4431 * HOL/List:
  4432   - new function list_update written xs[i:=v] that updates the i-th
  4433     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4434   - new function `upt' written [i..j(] which generates the list
  4435     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4436     bound write [i..j], which is a shorthand for [i..j+1(].
  4437   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4438 
  4439 * HOL/Arith:
  4440   - removed 'pred' (predecessor) function;
  4441   - generalized some theorems about n-1;
  4442   - many new laws about "div" and "mod";
  4443   - new laws about greatest common divisors (see theory ex/Primes);
  4444 
  4445 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4446 instead of "inverse";
  4447 
  4448 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4449   of the multiset ordering;
  4450 
  4451 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4452   (not included by default);
  4453 
  4454 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4455 
  4456 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4457   programs, i.e. different program variables may have different types.
  4458 
  4459 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4460   [previously, this check worked only if the rewrite rule was unconditional]
  4461   Now rew can involve either definitions or equalities (either == or =).
  4462 
  4463 
  4464 *** ZF ***
  4465 
  4466 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4467   only the theorems proved on ZF.ML;
  4468 
  4469 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4470   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4471   disjointness reasoning but breaking a few old proofs.
  4472 
  4473 * ZF/Update: new theory of function updates
  4474     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4475   may also be iterated as in f(a:=b,c:=d,...);
  4476 
  4477 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4478 
  4479 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4480   [previously, this check worked only if the rewrite rule was unconditional]
  4481   Now rew can involve either definitions or equalities (either == or =).
  4482 
  4483 * case_tac provided for compatibility with HOL
  4484     (like the old excluded_middle_tac, but with subgoals swapped)
  4485 
  4486 
  4487 *** Internal programming interfaces ***
  4488 
  4489 * Pure: several new basic modules made available for general use, see
  4490 also src/Pure/README;
  4491 
  4492 * improved the theory data mechanism to support encapsulation (data
  4493 kind name replaced by private Object.kind, acting as authorization
  4494 key); new type-safe user interface via functor TheoryDataFun; generic
  4495 print_data function becomes basically useless;
  4496 
  4497 * removed global_names compatibility flag -- all theory declarations
  4498 are qualified by default;
  4499 
  4500 * module Pure/Syntax now offers quote / antiquote translation
  4501 functions (useful for Hoare logic etc. with implicit dependencies);
  4502 see HOL/ex/Antiquote for an example use;
  4503 
  4504 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4505 cterm -> thm;
  4506 
  4507 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4508 subgoal;
  4509 
  4510 * Display.print_goals function moved to Locale.print_goals;
  4511 
  4512 * standard print function for goals supports current_goals_markers
  4513 variable for marking begin of proof, end of proof, start of goal; the
  4514 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4515 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4516 for example;
  4517 
  4518 
  4519 
  4520 New in Isabelle98 (January 1998)
  4521 --------------------------------
  4522 
  4523 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4524 
  4525 * changed lexical syntax of terms / types: dots made part of long
  4526 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4527 
  4528 * simpset (and claset) reference variable replaced by functions
  4529 simpset / simpset_ref;
  4530 
  4531 * no longer supports theory aliases (via merge) and non-trivial
  4532 implicit merge of thms' signatures;
  4533 
  4534 * most internal names of constants changed due to qualified names;
  4535 
  4536 * changed Pure/Sequence interface (see Pure/seq.ML);
  4537 
  4538 
  4539 *** General Changes ***
  4540 
  4541 * hierachically structured name spaces (for consts, types, axms, thms
  4542 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4543 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4544 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4545 long_names for fully qualified output names; NOTE: ML programs
  4546 (special tactics, packages etc.) referring to internal names may have
  4547 to be adapted to cope with fully qualified names; in case of severe
  4548 backward campatibility problems try setting 'global_names' at compile
  4549 time to have enrything declared within a flat name space; one may also
  4550 fine tune name declarations in theories via the 'global' and 'local'
  4551 section;
  4552 
  4553 * reimplemented the implicit simpset and claset using the new anytype
  4554 data filed in signatures; references simpset:simpset ref etc. are
  4555 replaced by functions simpset:unit->simpset and
  4556 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4557 to patch your ML files accordingly;
  4558 
  4559 * HTML output now includes theory graph data for display with Java
  4560 applet or isatool browser; data generated automatically via isatool
  4561 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4562 
  4563 * defs may now be conditional; improved rewrite_goals_tac to handle
  4564 conditional equations;
  4565 
  4566 * defs now admits additional type arguments, using TYPE('a) syntax;
  4567 
  4568 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4569 creates a new theory node; implicit merge of thms' signatures is
  4570 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4571 transfer:theory->thm->thm in (rare) cases;
  4572 
  4573 * improved handling of draft signatures / theories; draft thms (and
  4574 ctyps, cterms) are automatically promoted to real ones;
  4575 
  4576 * slightly changed interfaces for oracles: admit many per theory, named
  4577 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4578 
  4579 * print_goals: optional output of const types (set show_consts and
  4580 show_types);
  4581 
  4582 * improved output of warnings (###) and errors (***);
  4583 
  4584 * subgoal_tac displays a warning if the new subgoal has type variables;
  4585 
  4586 * removed old README and Makefiles;
  4587 
  4588 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4589 
  4590 * removed obsolete init_pps and init_database;
  4591 
  4592 * deleted the obsolete tactical STATE, which was declared by
  4593     fun STATE tacfun st = tacfun st st;
  4594 
  4595 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4596 (which abbreviates $HOME);
  4597 
  4598 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4599 use isatool fixseq to adapt your ML programs (this works for fully
  4600 qualified references to the Sequence structure only!);
  4601 
  4602 * use_thy no longer requires writable current directory; it always
  4603 reloads .ML *and* .thy file, if either one is out of date;
  4604 
  4605 
  4606 *** Classical Reasoner ***
  4607 
  4608 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4609 tactics that use classical reasoning to simplify a subgoal without
  4610 splitting it into several subgoals;
  4611 
  4612 * Safe_tac: like safe_tac but uses the default claset;
  4613 
  4614 
  4615 *** Simplifier ***
  4616 
  4617 * added simplification meta rules:
  4618     (asm_)(full_)simplify: simpset -> thm -> thm;
  4619 
  4620 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4621 logics (again);
  4622 
  4623 * added prems argument to simplification procedures;
  4624 
  4625 * HOL, FOL, ZF: added infix function `addsplits':
  4626   instead of `<simpset> setloop (split_tac <thms>)'
  4627   you can simply write `<simpset> addsplits <thms>'
  4628 
  4629 
  4630 *** Syntax ***
  4631 
  4632 * TYPE('a) syntax for type reflection terms;
  4633 
  4634 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4635 
  4636 * pretty printer: changed order of mixfix annotation preference (again!);
  4637 
  4638 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4639 
  4640 
  4641 *** HOL ***
  4642 
  4643 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4644   with `addloop' of the simplifier to faciliate case splitting in premises.
  4645 
  4646 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4647 
  4648 * HOL/Auth: new protocol proofs including some for the Internet
  4649   protocol TLS;
  4650 
  4651 * HOL/Map: new theory of `maps' a la VDM;
  4652 
  4653 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4654 cancelling out common nat summands from =, <, <= (in)equalities, or
  4655 differences; simplification procedures nat_cancel_factor for
  4656 cancelling common factor from =, <, <= (in)equalities over natural
  4657 sums; nat_cancel contains both kinds of procedures, it is installed by
  4658 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4659 
  4660 * HOL/simplifier: terms of the form
  4661   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4662   are rewritten to
  4663   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4664   and those of the form
  4665   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4666   are rewritten to
  4667   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4668 
  4669 * HOL/datatype
  4670   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4671 
  4672   P(t_case f1 ... fn x) =
  4673      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4674         ...
  4675        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4676      )
  4677 
  4678   and a theorem `split_t_case_asm' of the form
  4679 
  4680   P(t_case f1 ... fn x) =
  4681     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4682         ...
  4683        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4684      )
  4685   which can be added to a simpset via `addsplits'. The existing theorems
  4686   expand_list_case and expand_option_case have been renamed to
  4687   split_list_case and split_option_case.
  4688 
  4689 * HOL/Arithmetic:
  4690   - `pred n' is automatically converted to `n-1'.
  4691     Users are strongly encouraged not to use `pred' any longer,
  4692     because it will disappear altogether at some point.
  4693   - Users are strongly encouraged to write "0 < n" rather than
  4694     "n ~= 0". Theorems and proof tools have been modified towards this
  4695     `standard'.
  4696 
  4697 * HOL/Lists:
  4698   the function "set_of_list" has been renamed "set" (and its theorems too);
  4699   the function "nth" now takes its arguments in the reverse order and
  4700   has acquired the infix notation "!" as in "xs!n".
  4701 
  4702 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4703 
  4704 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4705   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4706 
  4707 * HOL/record: extensible records with schematic structural subtyping
  4708 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4709 still lacks various theorems and concrete record syntax;
  4710 
  4711 
  4712 *** HOLCF ***
  4713 
  4714 * removed "axioms" and "generated by" sections;
  4715 
  4716 * replaced "ops" section by extended "consts" section, which is capable of
  4717   handling the continuous function space "->" directly;
  4718 
  4719 * domain package:
  4720   . proves theorems immediately and stores them in the theory,
  4721   . creates hierachical name space,
  4722   . now uses normal mixfix annotations (instead of cinfix...),
  4723   . minor changes to some names and values (for consistency),
  4724   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4725   . separator between mutual domain defs: changed "," to "and",
  4726   . improved handling of sort constraints;  now they have to
  4727     appear on the left-hand side of the equations only;
  4728 
  4729 * fixed LAM <x,y,zs>.b syntax;
  4730 
  4731 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4732 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4733 
  4734 
  4735 *** FOL and ZF ***
  4736 
  4737 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4738   with `addloop' of the simplifier to faciliate case splitting in premises.
  4739 
  4740 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4741 in HOL, they strip ALL and --> from proved theorems;
  4742 
  4743 
  4744 
  4745 New in Isabelle94-8 (May 1997)
  4746 ------------------------------
  4747 
  4748 *** General Changes ***
  4749 
  4750 * new utilities to build / run / maintain Isabelle etc. (in parts
  4751 still somewhat experimental); old Makefiles etc. still functional;
  4752 
  4753 * new 'Isabelle System Manual';
  4754 
  4755 * INSTALL text, together with ./configure and ./build scripts;
  4756 
  4757 * reimplemented type inference for greater efficiency, better error
  4758 messages and clean internal interface;
  4759 
  4760 * prlim command for dealing with lots of subgoals (an easier way of
  4761 setting goals_limit);
  4762 
  4763 
  4764 *** Syntax ***
  4765 
  4766 * supports alternative (named) syntax tables (parser and pretty
  4767 printer); internal interface is provided by add_modesyntax(_i);
  4768 
  4769 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4770 be used in conjunction with the Isabelle symbol font; uses the
  4771 "symbols" syntax table;
  4772 
  4773 * added token_translation interface (may translate name tokens in
  4774 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4775 the current print_mode); IMPORTANT: user print translation functions
  4776 are responsible for marking newly introduced bounds
  4777 (Syntax.mark_boundT);
  4778 
  4779 * token translations for modes "xterm" and "xterm_color" that display
  4780 names in bold, underline etc. or colors (which requires a color
  4781 version of xterm);
  4782 
  4783 * infixes may now be declared with names independent of their syntax;
  4784 
  4785 * added typed_print_translation (like print_translation, but may
  4786 access type of constant);
  4787 
  4788 
  4789 *** Classical Reasoner ***
  4790 
  4791 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4792 some limitations.  Blast_tac...
  4793   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4794   + ignores elimination rules that don't have the correct format
  4795         (the conclusion MUST be a formula variable)
  4796   + ignores types, which can make HOL proofs fail
  4797   + rules must not require higher-order unification, e.g. apply_type in ZF
  4798     [message "Function Var's argument not a bound variable" relates to this]
  4799   + its proof strategy is more general but can actually be slower
  4800 
  4801 * substitution with equality assumptions no longer permutes other
  4802 assumptions;
  4803 
  4804 * minor changes in semantics of addafter (now called addaltern); renamed
  4805 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4806 (and access functions for it);
  4807 
  4808 * improved combination of classical reasoner and simplifier:
  4809   + functions for handling clasimpsets
  4810   + improvement of addss: now the simplifier is called _after_ the
  4811     safe steps.
  4812   + safe variant of addss called addSss: uses safe simplifications
  4813     _during_ the safe steps. It is more complete as it allows multiple
  4814     instantiations of unknowns (e.g. with slow_tac).
  4815 
  4816 *** Simplifier ***
  4817 
  4818 * added interface for simplification procedures (functions that
  4819 produce *proven* rewrite rules on the fly, depending on current
  4820 redex);
  4821 
  4822 * ordering on terms as parameter (used for ordered rewriting);
  4823 
  4824 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4825 
  4826 * the solver is now split into a safe and an unsafe part.
  4827 This should be invisible for the normal user, except that the
  4828 functions setsolver and addsolver have been renamed to setSolver and
  4829 addSolver; added safe_asm_full_simp_tac;
  4830 
  4831 
  4832 *** HOL ***
  4833 
  4834 * a generic induction tactic `induct_tac' which works for all datatypes and
  4835 also for type `nat';
  4836 
  4837 * a generic case distinction tactic `exhaust_tac' which works for all
  4838 datatypes and also for type `nat';
  4839 
  4840 * each datatype comes with a function `size';
  4841 
  4842 * patterns in case expressions allow tuple patterns as arguments to
  4843 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4844 
  4845 * primrec now also works with type nat;
  4846 
  4847 * recdef: a new declaration form, allows general recursive functions to be
  4848 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4849 
  4850 * the constant for negation has been renamed from "not" to "Not" to
  4851 harmonize with FOL, ZF, LK, etc.;
  4852 
  4853 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4854 infinite lists;
  4855 
  4856 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4857 
  4858 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4859 problems in commutative rings, using axiomatic type classes for + and *;
  4860 
  4861 * more examples in HOL/MiniML and HOL/Auth;
  4862 
  4863 * more default rewrite rules for quantifiers, union/intersection;
  4864 
  4865 * a new constant `arbitrary == @x.False';
  4866 
  4867 * HOLCF/IOA replaces old HOL/IOA;
  4868 
  4869 * HOLCF changes: derived all rules and arities
  4870   + axiomatic type classes instead of classes
  4871   + typedef instead of faking type definitions
  4872   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4873   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4874   + eliminated the types void, one, tr
  4875   + use unit lift and bool lift (with translations) instead of one and tr
  4876   + eliminated blift from Lift3.thy (use Def instead of blift)
  4877   all eliminated rules are derived as theorems --> no visible changes ;
  4878 
  4879 
  4880 *** ZF ***
  4881 
  4882 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4883 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4884 as ZF_cs addSIs [equalityI];
  4885 
  4886 
  4887 
  4888 New in Isabelle94-7 (November 96)
  4889 ---------------------------------
  4890 
  4891 * allowing negative levels (as offsets) in prlev and choplev;
  4892 
  4893 * super-linear speedup for large simplifications;
  4894 
  4895 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4896 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4897 FAIL); can suppress it using the command Delsimps (ex_simps @
  4898 all_simps); De Morgan laws are also now included, by default;
  4899 
  4900 * improved printing of ==>  :  ~:
  4901 
  4902 * new object-logic "Sequents" adds linear logic, while replacing LK
  4903 and Modal (thanks to Sara Kalvala);
  4904 
  4905 * HOL/Auth: correctness proofs for authentication protocols;
  4906 
  4907 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4908 examples on HOL/Auth);
  4909 
  4910 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4911 the rewriter and classical reasoner simultaneously;
  4912 
  4913 * function uresult no longer returns theorems in "standard" format;
  4914 regain previous version by: val uresult = standard o uresult;
  4915 
  4916 
  4917 
  4918 New in Isabelle94-6
  4919 -------------------
  4920 
  4921 * oracles -- these establish an interface between Isabelle and trusted
  4922 external reasoners, which may deliver results as theorems;
  4923 
  4924 * proof objects (in particular record all uses of oracles);
  4925 
  4926 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4927 
  4928 * "constdefs" section in theory files;
  4929 
  4930 * "primrec" section (HOL) no longer requires names;
  4931 
  4932 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4933 
  4934 
  4935 
  4936 New in Isabelle94-5
  4937 -------------------
  4938 
  4939 * reduced space requirements;
  4940 
  4941 * automatic HTML generation from theories;
  4942 
  4943 * theory files no longer require "..." (quotes) around most types;
  4944 
  4945 * new examples, including two proofs of the Church-Rosser theorem;
  4946 
  4947 * non-curried (1994) version of HOL is no longer distributed;
  4948 
  4949 
  4950 
  4951 New in Isabelle94-4
  4952 -------------------
  4953 
  4954 * greatly reduced space requirements;
  4955 
  4956 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4957 
  4958 * searchable theorem database (see the section "Retrieving theorems" on
  4959 page 8 of the Reference Manual);
  4960 
  4961 * new examples, including Grabczewski's monumental case study of the
  4962 Axiom of Choice;
  4963 
  4964 * The previous version of HOL renamed to Old_HOL;
  4965 
  4966 * The new version of HOL (previously called CHOL) uses a curried syntax
  4967 for functions.  Application looks like f a b instead of f(a,b);
  4968 
  4969 * Mutually recursive inductive definitions finally work in HOL;
  4970 
  4971 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4972 translates to the operator "split";
  4973 
  4974 
  4975 
  4976 New in Isabelle94-3
  4977 -------------------
  4978 
  4979 * new infix operator, addss, allowing the classical reasoner to
  4980 perform simplification at each step of its search.  Example:
  4981         fast_tac (cs addss ss)
  4982 
  4983 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4984 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4985 look like (a,b) instead of <a,b>;
  4986 
  4987 * PLEASE NOTE: CHOL will eventually replace HOL!
  4988 
  4989 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4990 It translates to the operator "split".  A new theory of integers is available;
  4991 
  4992 * In ZF, integer numerals now denote two's-complement binary integers.
  4993 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4994 
  4995 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4996 of the Axiom of Choice;
  4997 
  4998 
  4999 
  5000 New in Isabelle94-2
  5001 -------------------
  5002 
  5003 * Significantly faster resolution;
  5004 
  5005 * the different sections in a .thy file can now be mixed and repeated
  5006 freely;
  5007 
  5008 * Database of theorems for FOL, HOL and ZF.  New
  5009 commands including qed, qed_goal and bind_thm store theorems in the database.
  5010 
  5011 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5012 a given theory (thms_of), or find out what theory a theorem was proved in
  5013 (theory_of_thm);
  5014 
  5015 * Bugs fixed in the inductive definition and datatype packages;
  5016 
  5017 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5018 and HOL_dup_cs obsolete;
  5019 
  5020 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5021 have been removed;
  5022 
  5023 * Simpler definition of function space in ZF;
  5024 
  5025 * new results about cardinal and ordinal arithmetic in ZF;
  5026 
  5027 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5028 types;
  5029 
  5030 
  5031 $Id$