NEWS
author wenzelm
Wed Aug 08 23:07:46 2007 +0200 (2007-08-08)
changeset 24187 8bdf5ca5871f
parent 24172 06e42cf7df4e
child 24210 a865059c4fcb
permissions -rw-r--r--
* Theory loader: old-style ML proof scripts are considered a legacy feature;
     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.  The strict
    30 update policy of former update_thy is now already performed by
    31 use_thy, so the former has been removed; use_thys updates several
    32 theories simultaneously, just as 'imports' within a theory header
    33 specification, but without merging the results.  Potential
    34 INCOMPATIBILITY: may need to refine theory headers and commands
    35 ROOT.ML which depend on load order.
    36 
    37 * Theory loader: optional support for content-based file
    38 identification, instead of the traditional scheme of full physical
    39 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    40 (cf. the system manual).  The new scheme allows to work with
    41 non-finished theories in persistent session images, such that source
    42 files may be moved later on without requiring reloads.
    43 
    44 * Theory loader: old-style ML proof scripts being *attached* to a thy
    45 file (with the same base name as the theory) are considered a legacy
    46 feature, which will disappear eventually. Even now, the theory loader no
    47 longer maintains dependencies on such files.
    48 
    49 * Legacy goal package: reduced interface to the bare minimum required
    50 to keep existing proof scripts running.  Most other user-level
    51 functions are now part of the OldGoals structure, which is *not* open
    52 by default (consider isatool expandshort before open OldGoals).
    53 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    54 these tend to cause confusion about the actual goal (!) context being
    55 used here, which is not necessarily the same as the_context().
    56 
    57 * Command 'find_theorems': supports "*" wild-card in "name:"
    58 criterion; "with_dups" option.  Certain ProofGeneral versions might
    59 support a specific search form (see ProofGeneral/CHANGES).
    60 
    61 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    62 by default, which means that "prems" (and also "fixed variables") are
    63 suppressed from proof state output.  Note that the ProofGeneral
    64 settings mechanism allows to change and save options persistently, but
    65 older versions of Isabelle will fail to start up if a negative prems
    66 limit is imposed.
    67 
    68 * Local theory targets may be specified by non-nested blocks of
    69 ``context/locale/class ... begin'' followed by ``end''.  The body may
    70 contain definitions, theorems etc., including any derived mechanism
    71 that has been implemented on top of these primitives.  This concept
    72 generalizes the existing ``theorem (in ...)'' towards more versatility
    73 and scalability.
    74 
    75 * Proof General interface: proper undo of final 'end' command;
    76 discontinued Isabelle/classic mode (ML proof scripts).
    77 
    78 
    79 *** Document preparation ***
    80 
    81 * Added antiquotation @{theory name} which prints the given name,
    82 after checking that it refers to a valid ancestor theory in the
    83 current context.
    84 
    85 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    86 check the given source text as ML type/structure, printing verbatim.
    87 
    88 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    89 "c args == rhs" given in the current context.  (Any number of
    90 arguments may be given on the LHS.)
    91 
    92 
    93 
    94 *** Pure ***
    95 
    96 * code generator: consts in 'consts_code' Isar commands are now referred
    97   to by usual term syntax (including optional type annotations).
    98 
    99 * code generator: 
   100   - Isar 'definition's, 'constdef's and primitive instance definitions are added
   101     explicitly to the table of defining equations
   102   - primitive definitions are not used as defining equations by default any longer
   103   - defining equations are now definitly restricted to meta "==" and object
   104         equality "="
   105   - HOL theories have been adopted accordingly
   106 
   107 * class_package.ML offers a combination of axclasses and locales to
   108 achieve Haskell-like type classes in Isabelle.  See
   109 HOL/ex/Classpackage.thy for examples.
   110 
   111 * Yet another code generator framework allows to generate executable
   112 code for ML and Haskell (including "class"es).  A short usage sketch:
   113 
   114     internal compilation:
   115         code_gen <list of constants (term syntax)> in SML
   116     writing SML code to a file:
   117         code_gen <list of constants (term syntax)> in SML <filename>
   118     writing OCaml code to a file:
   119         code_gen <list of constants (term syntax)> in OCaml <filename>
   120     writing Haskell code to a bunch of files:
   121         code_gen <list of constants (term syntax)> in Haskell <filename>
   122 
   123 Reasonable default setup of framework in HOL/Main.
   124 
   125 Theorem attributs for selecting and transforming function equations theorems:
   126 
   127     [code fun]:        select a theorem as function equation for a specific constant
   128     [code fun del]:    deselect a theorem as function equation for a specific constant
   129     [code inline]:     select an equation theorem for unfolding (inlining) in place
   130     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   131 
   132 User-defined serializations (target in {SML, OCaml, Haskell}):
   133 
   134     code_const <and-list of constants (term syntax)>
   135       {(target) <and-list of const target syntax>}+
   136 
   137     code_type <and-list of type constructors>
   138       {(target) <and-list of type target syntax>}+
   139 
   140     code_instance <and-list of instances>
   141       {(target)}+
   142         where instance ::= <type constructor> :: <class>
   143 
   144     code_class <and_list of classes>
   145       {(target) <and-list of class target syntax>}+
   146         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   147 
   148 code_instance and code_class only apply to target Haskell.
   149 
   150 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   151 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   152 
   153 * Command 'no_translations' removes translation rules from theory
   154 syntax.
   155 
   156 * Overloaded definitions are now actually checked for acyclic
   157 dependencies.  The overloading scheme is slightly more general than
   158 that of Haskell98, although Isabelle does not demand an exact
   159 correspondence to type class and instance declarations.
   160 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   161 exotic versions of overloading -- at the discretion of the user!
   162 
   163 Polymorphic constants are represented via type arguments, i.e. the
   164 instantiation that matches an instance against the most general
   165 declaration given in the signature.  For example, with the declaration
   166 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   167 as c(nat).  Overloading is essentially simultaneous structural
   168 recursion over such type arguments.  Incomplete specification patterns
   169 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   170 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   171 Command 'print_theory' outputs the normalized system of recursive
   172 equations, see section "definitions".
   173 
   174 * Configuration options are maintained within the theory or proof
   175 context (with name and type bool/int/string), providing a very simple
   176 interface to a poor-man's version of general context data.  Tools may
   177 declare options in ML (e.g. using Attrib.config_int) and then refer to
   178 these values using Config.get etc.  Users may change options via an
   179 associated attribute of the same name.  This form of context
   180 declaration works particularly well with commands 'declare' or
   181 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   182 very easy to avoid global references, which would not observe Isar
   183 toplevel undo/redo and fail to work with multithreading.
   184 
   185 Various global ML references of Pure and HOL have been turned into
   186 configuration options:
   187 
   188   Unify.search_bound		unify_search_bound
   189   Unify.trace_bound		unify_trace_bound
   190   Unify.trace_simp		unify_trace_simp
   191   Unify.trace_types		unify_trace_types
   192   Simplifier.simp_depth_limit	simp_depth_limit
   193   Blast.depth_limit		blast_depth_limit
   194   DatatypeProp.dtK		datatype_distinctness_limit
   195   fast_arith_neq_limit  	fast_arith_neq_limit
   196   fast_arith_split_limit	fast_arith_split_limit
   197 
   198 * Named collections of theorems may be easily installed as context
   199 data using the functor NamedThmsFun (see
   200 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   201 attributes; there is also a toplevel print command.  This facility is
   202 just a common case of general context data, which is the preferred way
   203 for anything more complex than just a list of facts in canonical
   204 order.
   205 
   206 * Isar: command 'declaration' augments a local theory by generic
   207 declaration functions written in ML.  This enables arbitrary content
   208 being added to the context, depending on a morphism that tells the
   209 difference of the original declaration context wrt. the application
   210 context encountered later on.
   211 
   212 * Isar: proper interfaces for simplification procedures.  Command
   213 'simproc_setup' declares named simprocs (with match patterns, and body
   214 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   215 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   216 
   217 * Isar: an extra pair of brackets around attribute declarations
   218 abbreviates a theorem reference involving an internal dummy fact,
   219 which will be ignored later --- only the effect of the attribute on
   220 the background context will persist.  This form of in-place
   221 declarations is particularly useful with commands like 'declare' and
   222 'using', for example ``have A using [[simproc a]] by simp''.
   223 
   224 * Isar: method "assumption" (and implicit closing of subproofs) now
   225 takes simple non-atomic goal assumptions into account: after applying
   226 an assumption as a rule the resulting subgoals are solved by atomic
   227 assumption steps.  This is particularly useful to finish 'obtain'
   228 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   229 without referring to the original premise "!!x. P x ==> thesis" in the
   230 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   231 more permissive.
   232 
   233 * Isar: implicit use of prems from the Isar proof context is
   234 considered a legacy feature.  Common applications like ``have A .''
   235 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   236 referencing facts explicitly here improves readability and
   237 maintainability of proof texts.
   238 
   239 * Isar: improper proof element 'guess' is like 'obtain', but derives
   240 the obtained context from the course of reasoning!  For example:
   241 
   242   assume "EX x y. A x & B y"   -- "any previous fact"
   243   then guess x and y by clarify
   244 
   245 This technique is potentially adventurous, depending on the facts and
   246 proof tools being involved here.
   247 
   248 * Isar: known facts from the proof context may be specified as literal
   249 propositions, using ASCII back-quote syntax.  This works wherever
   250 named facts used to be allowed so far, in proof commands, proof
   251 methods, attributes etc.  Literal facts are retrieved from the context
   252 according to unification of type and term parameters.  For example,
   253 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   254 theorems in the current context, then these are valid literal facts:
   255 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   256 
   257 There is also a proof method "fact" which does the same composition
   258 for explicit goal states, e.g. the following proof texts coincide with
   259 certain special cases of literal facts:
   260 
   261   have "A" by fact                 ==  note `A`
   262   have "A ==> B" by fact           ==  note `A ==> B`
   263   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   264   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   265 
   266 * Isar: ":" (colon) is no longer a symbolic identifier character in
   267 outer syntax.  Thus symbolic identifiers may be used without
   268 additional white space in declarations like this: ``assume *: A''.
   269 
   270 * Isar: 'print_facts' prints all local facts of the current context,
   271 both named and unnamed ones.
   272 
   273 * Isar: 'def' now admits simultaneous definitions, e.g.:
   274 
   275   def x == "t" and y == "u"
   276 
   277 * Isar: added command 'unfolding', which is structurally similar to
   278 'using', but affects both the goal state and facts by unfolding given
   279 rewrite rules.  Thus many occurrences of the 'unfold' method or
   280 'unfolded' attribute may be replaced by first-class proof text.
   281 
   282 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   283 and command 'unfolding' now all support object-level equalities
   284 (potentially conditional).  The underlying notion of rewrite rule is
   285 analogous to the 'rule_format' attribute, but *not* that of the
   286 Simplifier (which is usually more generous).
   287 
   288 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   289 method expression within a sandbox consisting of the first N
   290 sub-goals, which need to exist.  For example, ``simp_all [3]''
   291 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   292 simplifies all new goals that emerge from applying rule foo to the
   293 originally first one.
   294 
   295 * Isar: schematic goals are no longer restricted to higher-order
   296 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   297 expected.
   298 
   299 * Isar: the conclusion of a long theorem statement is now either
   300 'shows' (a simultaneous conjunction, as before), or 'obtains'
   301 (essentially a disjunction of cases with local parameters and
   302 assumptions).  The latter allows to express general elimination rules
   303 adequately; in this notation common elimination rules look like this:
   304 
   305   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   306     assumes "EX x. P x"
   307     obtains x where "P x"
   308 
   309   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   310     assumes "A & B"
   311     obtains A and B
   312 
   313   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   314     assumes "A | B"
   315     obtains
   316       A
   317     | B
   318 
   319 The subsequent classical rules even refer to the formal "thesis"
   320 explicitly:
   321 
   322   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   323     obtains "~ thesis"
   324 
   325   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   326     obtains "thesis ==> something"
   327 
   328 The actual proof of an 'obtains' statement is analogous to that of the
   329 Isar proof element 'obtain', only that there may be several cases.
   330 Optional case names may be specified in parentheses; these will be
   331 available both in the present proof and as annotations in the
   332 resulting rule, for later use with the 'cases' method (cf. attribute
   333 case_names).
   334 
   335 * Isar: the assumptions of a long theorem statement are available as
   336 "assms" fact in the proof context.  This is more appropriate than the
   337 (historical) "prems", which refers to all assumptions of the current
   338 context, including those from the target locale, proof body etc.
   339 
   340 * Isar: 'print_statement' prints theorems from the current theory or
   341 proof context in long statement form, according to the syntax of a
   342 top-level lemma.
   343 
   344 * Isar: 'obtain' takes an optional case name for the local context
   345 introduction rule (default "that").
   346 
   347 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   348 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   349 to occur.
   350 
   351 * Pure: syntax "CONST name" produces a fully internalized constant
   352 according to the current context.  This is particularly useful for
   353 syntax translations that should refer to internal constant
   354 representations independently of name spaces.
   355 
   356 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   357 instead of "FOO ". This allows multiple binder declarations to coexist
   358 in the same context.  INCOMPATIBILITY.
   359 
   360 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   361 primitive that also works in a locale context (both for constants and
   362 fixed variables).  Type declaration and internal syntactic
   363 representation of given constants retrieved from the context.
   364 
   365 * Isar/locales: new derived specification elements 'axiomatization',
   366 'definition', 'abbreviation', which support type-inference, admit
   367 object-level specifications (equality, equivalence).  See also the
   368 isar-ref manual.  Examples:
   369 
   370   axiomatization
   371     eq  (infix "===" 50) where
   372     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   373 
   374   definition "f x y = x + y + 1"
   375   definition g where "g x = f x x"
   376 
   377   abbreviation
   378     neq  (infix "=!=" 50) where
   379     "x =!= y == ~ (x === y)"
   380 
   381 These specifications may be also used in a locale context.  Then the
   382 constants being introduced depend on certain fixed parameters, and the
   383 constant name is qualified by the locale base name.  An internal
   384 abbreviation takes care for convenient input and output, making the
   385 parameters implicit and using the original short name.  See also
   386 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   387 entities from a monomorphic theory.
   388 
   389 Presently, abbreviations are only available 'in' a target locale, but
   390 not inherited by general import expressions.  Also note that
   391 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   392 'translations' in common applications.
   393 
   394 Concrete syntax is attached to specified constants in internal form,
   395 independently of name spaces.  The parse tree representation is
   396 slightly different -- use 'notation' instead of raw 'syntax', and
   397 'translations' with explicit "CONST" markup to accommodate this.
   398 
   399 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   400 the current context.  Print mode "no_abbrevs" prevents inversion of
   401 abbreviations on output.
   402 
   403 * Isar/locales: improved parameter handling:
   404 - use of locales "var" and "struct" no longer necessary;
   405 - parameter renamings are no longer required to be injective.
   406   This enables, for example, to define a locale for endomorphisms thus:
   407   locale endom = homom mult mult h.
   408 
   409 * Isar/locales: changed the way locales with predicates are defined.
   410 Instead of accumulating the specification, the imported expression is
   411 now an interpretation.  INCOMPATIBILITY: different normal form of
   412 locale expressions.  In particular, in interpretations of locales with
   413 predicates, goals repesenting already interpreted fragments are not
   414 removed automatically.  Use methods `intro_locales' and
   415 `unfold_locales'; see below.
   416 
   417 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   418 provide backward reasoning on locales predicates.  The methods are
   419 aware of interpretations and discharge corresponding goals.
   420 `intro_locales' is less aggressive then `unfold_locales' and does not
   421 unfold predicates to assumptions.
   422 
   423 * Isar/locales: the order in which locale fragments are accumulated
   424 has changed.  This enables to override declarations from fragments due
   425 to interpretations -- for example, unwanted simp rules.
   426 
   427 * Isar/locales: interpretation in theories and proof contexts has been
   428 extended.  One may now specify (and prove) equations, which are
   429 unfolded in interpreted theorems.  This is useful for replacing
   430 defined concepts (constants depending on locale parameters) by
   431 concepts already existing in the target context.  Example:
   432 
   433   interpretation partial_order ["op <= :: [int, int] => bool"]
   434     where "partial_order.less (op <=) (x::int) y = (x < y)"
   435 
   436 Typically, the constant `partial_order.less' is created by a definition
   437 specification element in the context of locale partial_order.
   438 
   439 * Provers/induct: improved internal context management to support
   440 local fixes and defines on-the-fly.  Thus explicit meta-level
   441 connectives !! and ==> are rarely required anymore in inductive goals
   442 (using object-logic connectives for this purpose has been long
   443 obsolete anyway).  The subsequent proof patterns illustrate advanced
   444 techniques of natural induction; general datatypes and inductive sets
   445 work analogously (see also src/HOL/Lambda for realistic examples).
   446 
   447 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   448 parameters:
   449 
   450   lemma
   451     fixes n :: nat and x :: 'a
   452     assumes a: "A n x"
   453     shows "P n x"
   454     using a                     -- {* make induct insert fact a *}
   455   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   456     case 0
   457     show ?case sorry
   458   next
   459     case (Suc n)
   460     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   461     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   462     show ?case sorry
   463   qed
   464 
   465 (2) This is how to perform induction over ``expressions of a certain
   466 form'', using a locally defined inductive parameter n == "a x"
   467 together with strengthening (the latter is usually required to get
   468 sufficiently flexible induction hypotheses):
   469 
   470   lemma
   471     fixes a :: "'a => nat"
   472     assumes a: "A (a x)"
   473     shows "P (a x)"
   474     using a
   475   proof (induct n == "a x" arbitrary: x)
   476     ...
   477 
   478 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   479 particular technique.
   480 
   481 (3) This is how to perform existential reasoning ('obtains' or
   482 'obtain') by induction, while avoiding explicit object-logic
   483 encodings:
   484 
   485   lemma
   486     fixes n :: nat
   487     obtains x :: 'a where "P n x" and "Q n x"
   488   proof (induct n arbitrary: thesis)
   489     case 0
   490     obtain x where "P 0 x" and "Q 0 x" sorry
   491     then show thesis by (rule 0)
   492   next
   493     case (Suc n)
   494     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   495     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   496     then show thesis by (rule Suc.prems)
   497   qed
   498 
   499 Here the 'arbitrary: thesis' specification essentially modifies the
   500 scope of the formal thesis parameter, in order to the get the whole
   501 existence statement through the induction as expected.
   502 
   503 * Provers/induct: mutual induction rules are now specified as a list
   504 of rule sharing the same induction cases.  HOL packages usually
   505 provide foo_bar.inducts for mutually defined items foo and bar
   506 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   507 specify mutual induction rules differently, i.e. like this:
   508 
   509   (induct rule: foo_bar.inducts)
   510   (induct set: foo bar)
   511   (induct type: foo bar)
   512 
   513 The ML function ProjectRule.projections turns old-style rules into the
   514 new format.
   515 
   516 * Provers/induct: improved handling of simultaneous goals.  Instead of
   517 introducing object-level conjunction, the statement is now split into
   518 several conclusions, while the corresponding symbolic cases are
   519 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   520 explicitly.  For example:
   521 
   522   lemma
   523     fixes n :: nat
   524     shows "P n" and "Q n"
   525   proof (induct n)
   526     case 0 case 1
   527     show "P 0" sorry
   528   next
   529     case 0 case 2
   530     show "Q 0" sorry
   531   next
   532     case (Suc n) case 1
   533     note `P n` and `Q n`
   534     show "P (Suc n)" sorry
   535   next
   536     case (Suc n) case 2
   537     note `P n` and `Q n`
   538     show "Q (Suc n)" sorry
   539   qed
   540 
   541 The split into subcases may be deferred as follows -- this is
   542 particularly relevant for goal statements with local premises.
   543 
   544   lemma
   545     fixes n :: nat
   546     shows "A n ==> P n" and "B n ==> Q n"
   547   proof (induct n)
   548     case 0
   549     {
   550       case 1
   551       note `A 0`
   552       show "P 0" sorry
   553     next
   554       case 2
   555       note `B 0`
   556       show "Q 0" sorry
   557     }
   558   next
   559     case (Suc n)
   560     note `A n ==> P n` and `B n ==> Q n`
   561     {
   562       case 1
   563       note `A (Suc n)`
   564       show "P (Suc n)" sorry
   565     next
   566       case 2
   567       note `B (Suc n)`
   568       show "Q (Suc n)" sorry
   569     }
   570   qed
   571 
   572 If simultaneous goals are to be used with mutual rules, the statement
   573 needs to be structured carefully as a two-level conjunction, using
   574 lists of propositions separated by 'and':
   575 
   576   lemma
   577     shows "a : A ==> P1 a"
   578           "a : A ==> P2 a"
   579       and "b : B ==> Q1 b"
   580           "b : B ==> Q2 b"
   581           "b : B ==> Q3 b"
   582   proof (induct set: A B)
   583 
   584 * Provers/induct: support coinduction as well.  See
   585 src/HOL/Library/Coinductive_List.thy for various examples.
   586 
   587 * Attribute "symmetric" produces result with standardized schematic
   588 variables (index 0).  Potential INCOMPATIBILITY.
   589 
   590 * Simplifier: by default the simplifier trace only shows top level
   591 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   592 default. Thus there is less danger of being flooded by the trace. The
   593 trace indicates where parts have been suppressed.
   594   
   595 * Provers/classical: removed obsolete classical version of elim_format
   596 attribute; classical elim/dest rules are now treated uniformly when
   597 manipulating the claset.
   598 
   599 * Provers/classical: stricter checks to ensure that supplied intro,
   600 dest and elim rules are well-formed; dest and elim rules must have at
   601 least one premise.
   602 
   603 * Provers/classical: attributes dest/elim/intro take an optional
   604 weight argument for the rule (just as the Pure versions).  Weights are
   605 ignored by automated tools, but determine the search order of single
   606 rule steps.
   607 
   608 * Syntax: input syntax now supports dummy variable binding "%_. b",
   609 where the body does not mention the bound variable.  Note that dummy
   610 patterns implicitly depend on their context of bounds, which makes
   611 "{_. _}" match any set comprehension as expected.  Potential
   612 INCOMPATIBILITY -- parse translations need to cope with syntactic
   613 constant "_idtdummy" in the binding position.
   614 
   615 * Syntax: removed obsolete syntactic constant "_K" and its associated
   616 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   617 for example "A -> B" => "Pi A (%_. B)".
   618 
   619 * Pure: 'class_deps' command visualizes the subclass relation, using
   620 the graph browser tool.
   621 
   622 * Pure: 'print_theory' now suppresses entities with internal name
   623 (trailing "_") by default; use '!' option for full details.
   624 
   625 
   626 *** HOL ***
   627 
   628 * Code generator library theories:
   629   * Pretty_Int represents HOL integers by big integer literals in target
   630     languages.
   631   * Pretty_Char represents HOL characters by character literals in target
   632     languages.
   633   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   634     codes; includes Pretty_Int.
   635   * Executable_Set allows to generate code for finite sets using lists.
   636   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   637     denominator).
   638   * Executable_Real implements a subset of real numbers, namly those
   639     representable by rational numbers.
   640   * Efficient_Nat implements natural numbers by integers, which in general will
   641     result in higher efficency; pattern matching with 0/Suc is eliminated;
   642     includes Pretty_Int.
   643   * ML_String provides an additional datatype ml_string; in the HOL default
   644     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   645     of type ml_string are mapped to strings in SML.
   646   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   647     built-in integers.
   648 
   649 * New package for inductive predicates
   650 
   651   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   652 
   653     inductive
   654       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   655       for z_1 :: U_1 and ... and z_n :: U_m
   656     where
   657       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   658     | ...
   659 
   660   rather than
   661 
   662     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   663 
   664     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   665     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   666 
   667     inductive "s z_1 ... z_m"
   668     intros
   669       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   670       ...
   671 
   672   For backward compatibility, there is a wrapper allowing inductive
   673   sets to be defined with the new package via
   674 
   675     inductive_set
   676       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   677       for z_1 :: U_1 and ... and z_n :: U_m
   678     where
   679       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   680     | ...
   681 
   682   or
   683 
   684     inductive_set
   685       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   686       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   687       for z_1 :: U_1 and ... and z_n :: U_m
   688     where
   689       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   690     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   691     | ...
   692 
   693   if the additional syntax "p ..." is required.
   694 
   695   Many examples can be found in the subdirectories Auth, Bali, Induct,
   696   or MicroJava.
   697 
   698   INCOMPATIBILITIES:
   699 
   700   - Since declaration and definition of inductive sets or predicates
   701     is no longer separated, abbreviations involving the newly introduced
   702     sets or predicates must be specified together with the introduction
   703     rules after the "where" keyword (see example above), rather than before
   704     the actual inductive definition.
   705 
   706   - The variables in induction and elimination rules are now quantified
   707     in the order of their occurrence in the introduction rules, rather than
   708     in alphabetical order. Since this may break some proofs, these proofs
   709     either have to be repaired, e.g. by reordering the variables
   710     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   711 
   712       case (rule_i a_i_1 ... a_i_{k_i})
   713 
   714     or the old order of quantification has to be restored by explicitly adding
   715     meta-level quantifiers in the introduction rules, i.e.
   716 
   717       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   718 
   719   - The format of the elimination rules is now
   720 
   721       p z_1 ... z_m x_1 ... x_n ==>
   722         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   723         ==> ... ==> P
   724 
   725     for predicates and
   726 
   727       (x_1, ..., x_n) : s z_1 ... z_m ==>
   728         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   729         ==> ... ==> P
   730 
   731     for sets rather than
   732 
   733       x : s z_1 ... z_m ==>
   734         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   735         ==> ... ==> P
   736 
   737     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   738     or simplification with the split_paired_all rule) before the above elimination
   739     rule is applicable.
   740 
   741   - The elimination or case analysis rules for (mutually) inductive sets or
   742     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   743     "p_1_..._p_k.elims" is no longer available.
   744 
   745 * Method "metis" proves goals by applying the Metis general-purpose
   746 resolution prover.  Examples are in the directory MetisExamples.  See
   747 also http://gilith.com/software/metis/
   748   
   749 * Command 'sledgehammer' invokes external automatic theorem provers as
   750 background processes.  It generates calls to the "metis" method if
   751 successful. These can be pasted into the proof.  Users do not have to
   752 wait for the automatic provers to return.
   753 
   754 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   755   take their order into account, like in functional programming.
   756   Internally, this is translated into nested case-expressions; missing cases
   757   are added and mapped to the predefined constant "undefined". In complicated
   758   cases printing may no longer show the original input but the internal
   759   form. Lambda-abstractions allow the same form of pattern matching:
   760   "% pat1 => e1 | ..." is an abbreviation for
   761   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   762 
   763 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   764   is an abbreviation for "of_nat :: nat => int". The simplification rules
   765   for "of_nat" have been changed to work like "int" did previously.
   766   (potential INCOMPATIBILITY)
   767   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   768   - of_nat_diff and of_nat_mult are no longer default simp rules
   769 
   770 * Method "algebra" solves polynomial equations over (semi)rings using
   771   Groebner bases. The (semi)ring structure is defined by locales and
   772   the tool setup depends on that generic context. Installing the
   773   method for a specific type involves instantiating the locale and
   774   possibly adding declarations for computation on the coefficients.
   775   The method is already instantiated for natural numbers and for the
   776   axiomatic class of idoms with numerals.  See also the paper by
   777   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   778   underlying this architecture of context-aware proof-tools.
   779 
   780 * constant "List.op @" now named "List.append".  Use ML antiquotations
   781 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   782 possible incompatibilities when working on ML level.
   783 
   784 * Constant renames due to introduction of canonical name prefixing for
   785   class package:
   786 
   787     HOL.abs ~> HOL.minus_class.abs
   788     HOL.divide ~> HOL.divide_class.divide
   789     Nat.power ~> Nat.power_class.power
   790     Nat.size ~> Nat.size_class.size
   791     Numeral.number_of ~> Numeral.number_class.number_of
   792     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   793 
   794 * Rudimentary class target mechanism involves constant renames:
   795 
   796     Orderings.min ~> Orderings.ord_class.min
   797     Orderings.max ~> Orderings.ord_class.max
   798     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   799 
   800 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   801 
   802 * new constant "undefined" with axiom "undefined x = undefined"
   803 
   804 * new class "default" with associated constant "default"
   805 
   806 * new function listsum :: 'a list => 'a for arbitrary monoids.
   807   Special syntax: "SUM x <- xs. f x" (and latex variants)
   808 
   809 * new (input only) syntax for Haskell-like list comprehension, eg
   810   [(x,y). x <- xs, y <- ys, x ~= y]
   811   For details see List.thy.
   812 
   813 * The special syntax for function "filter" has changed from [x : xs. P] to
   814   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   815   and for uniformity. INCOMPATIBILITY
   816 
   817 * Lemma "set_take_whileD" renamed to "set_takeWhileD"
   818 
   819 * New lemma collection field_simps (an extension of ring_simps)
   820   for manipulating (in)equations involving division. Multiplies
   821   with all denominators that can be proved to be non-zero (in equations)
   822   or positive/negative (in inequations).
   823 
   824 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   825   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   826   Removed lemmas field_xyz in Ring_and_Field
   827   because they were subsumed by lemmas xyz.
   828 INCOMPATIBILITY.
   829 
   830 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   831   when generating code.
   832 
   833 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   834   when generating code.
   835 
   836 * Library/Commutative_Ring.thy: switched from recdef to function package;
   837   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   838 
   839 * Some steps towards more uniform lattice theory development in HOL.
   840 
   841     constants "meet" and "join" now named "inf" and "sup"
   842     constant "Meet" now named "Inf"
   843 
   844     classes "meet_semilorder" and "join_semilorder" now named
   845       "lower_semilattice" and "upper_semilattice"
   846     class "lorder" now named "lattice"
   847     class "comp_lat" now named "complete_lattice"
   848 
   849     Instantiation of lattice classes allows explicit definitions
   850     for "inf" and "sup" operations.
   851 
   852   INCOMPATIBILITY.  Theorem renames:
   853 
   854     meet_left_le            ~> inf_le1
   855     meet_right_le           ~> inf_le2
   856     join_left_le            ~> sup_ge1
   857     join_right_le           ~> sup_ge2
   858     meet_join_le            ~> inf_sup_ord
   859     le_meetI                ~> le_infI
   860     join_leI                ~> le_supI
   861     le_meet                 ~> le_inf_iff
   862     le_join                 ~> ge_sup_conv
   863     meet_idempotent         ~> inf_idem
   864     join_idempotent         ~> sup_idem
   865     meet_comm               ~> inf_commute
   866     join_comm               ~> sup_commute
   867     meet_leI1               ~> le_infI1
   868     meet_leI2               ~> le_infI2
   869     le_joinI1               ~> le_supI1
   870     le_joinI2               ~> le_supI2
   871     meet_assoc              ~> inf_assoc
   872     join_assoc              ~> sup_assoc
   873     meet_left_comm          ~> inf_left_commute
   874     meet_left_idempotent    ~> inf_left_idem
   875     join_left_comm          ~> sup_left_commute
   876     join_left_idempotent    ~> sup_left_idem
   877     meet_aci                ~> inf_aci
   878     join_aci                ~> sup_aci
   879     le_def_meet             ~> le_iff_inf
   880     le_def_join             ~> le_iff_sup
   881     join_absorp2            ~> sup_absorb2
   882     join_absorp1            ~> sup_absorb1
   883     meet_absorp1            ~> inf_absorb1
   884     meet_absorp2            ~> inf_absorb2
   885     meet_join_absorp        ~> inf_sup_absorb
   886     join_meet_absorp        ~> sup_inf_absorb
   887     distrib_join_le         ~> distrib_sup_le
   888     distrib_meet_le         ~> distrib_inf_le
   889 
   890     add_meet_distrib_left   ~> add_inf_distrib_left
   891     add_join_distrib_left   ~> add_sup_distrib_left
   892     is_join_neg_meet        ~> is_join_neg_inf
   893     is_meet_neg_join        ~> is_meet_neg_sup
   894     add_meet_distrib_right  ~> add_inf_distrib_right
   895     add_join_distrib_right  ~> add_sup_distrib_right
   896     add_meet_join_distribs  ~> add_sup_inf_distribs
   897     join_eq_neg_meet        ~> sup_eq_neg_inf
   898     meet_eq_neg_join        ~> inf_eq_neg_sup
   899     add_eq_meet_join        ~> add_eq_inf_sup
   900     meet_0_imp_0            ~> inf_0_imp_0
   901     join_0_imp_0            ~> sup_0_imp_0
   902     meet_0_eq_0             ~> inf_0_eq_0
   903     join_0_eq_0             ~> sup_0_eq_0
   904     neg_meet_eq_join        ~> neg_inf_eq_sup
   905     neg_join_eq_meet        ~> neg_sup_eq_inf
   906     join_eq_if              ~> sup_eq_if
   907 
   908     mono_meet               ~> mono_inf
   909     mono_join               ~> mono_sup
   910     meet_bool_eq            ~> inf_bool_eq
   911     join_bool_eq            ~> sup_bool_eq
   912     meet_fun_eq             ~> inf_fun_eq
   913     join_fun_eq             ~> sup_fun_eq
   914     meet_set_eq             ~> inf_set_eq
   915     join_set_eq             ~> sup_set_eq
   916     meet1_iff               ~> inf1_iff
   917     meet2_iff               ~> inf2_iff
   918     meet1I                  ~> inf1I
   919     meet2I                  ~> inf2I
   920     meet1D1                 ~> inf1D1
   921     meet2D1                 ~> inf2D1
   922     meet1D2                 ~> inf1D2
   923     meet2D2                 ~> inf2D2
   924     meet1E                  ~> inf1E
   925     meet2E                  ~> inf2E
   926     join1_iff               ~> sup1_iff
   927     join2_iff               ~> sup2_iff
   928     join1I1                 ~> sup1I1
   929     join2I1                 ~> sup2I1
   930     join1I1                 ~> sup1I1
   931     join2I2                 ~> sup1I2
   932     join1CI                 ~> sup1CI
   933     join2CI                 ~> sup2CI
   934     join1E                  ~> sup1E
   935     join2E                  ~> sup2E
   936 
   937     is_meet_Meet            ~> is_meet_Inf
   938     Meet_bool_def           ~> Inf_bool_def
   939     Meet_fun_def            ~> Inf_fun_def
   940     Meet_greatest           ~> Inf_greatest
   941     Meet_lower              ~> Inf_lower
   942     Meet_set_def            ~> Inf_set_def
   943 
   944     listsp_meetI            ~> listsp_infI
   945     listsp_meet_eq          ~> listsp_inf_eq
   946 
   947     meet_min                ~> inf_min
   948     join_max                ~> sup_max
   949 
   950 * Classes "order" and "linorder": facts "refl", "trans" and
   951 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   952 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   953 
   954 * Classes "order" and "linorder": 
   955 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   956 proofs changed.
   957 
   958 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   959 INCOMPATIBILITY.
   960 
   961 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   962 INCOMPATIBILITY.
   963 
   964 * Added syntactic class "size"; overloaded constant "size" now has
   965 type "'a::size ==> bool"
   966 
   967 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   968 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   969 
   970 * Added method "lexicographic_order" automatically synthesizes
   971 termination relations as lexicographic combinations of size measures
   972 -- 'function' package.
   973 
   974 * HOL/records: generalised field-update to take a function on the
   975 field rather than the new value: r(|A := x|) is translated to A_update
   976 (K x) r The K-combinator that is internally used is called K_record.
   977 INCOMPATIBILITY: Usage of the plain update functions has to be
   978 adapted.
   979  
   980 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   981 0 * x = 0, which are required for a semiring.  Richer structures do
   982 not inherit from semiring_0 anymore, because this property is a
   983 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   984 semiring_0, there is more to prove, but this is mostly trivial.
   985 
   986 * axclass "recpower" was generalized to arbitrary monoids, not just
   987 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   988 commutativity or a semiring property, add the corresponding classes.
   989 
   990 * Unified locale partial_order with class definition (cf. theory
   991 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   992 
   993 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   994 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   995 Isar level, use abbreviations instead.
   996 
   997 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   998 rarely occuring name references (e.g. ``List.op mem.simps'') require
   999 renaming (e.g. ``List.memberl.simps'').
  1000 
  1001 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
  1002 INCOMPATIBILITY.
  1003 
  1004 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
  1005 
  1006 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1007 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
  1008 significant changes for setting up numeral syntax for types:
  1009 
  1010   - new constants Numeral.pred and Numeral.succ instead
  1011       of former Numeral.bin_pred and Numeral.bin_succ.
  1012   - Use integer operations instead of bin_add, bin_mult and so on.
  1013   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1014   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1015 
  1016 See HOL/Integ/IntArith.thy for an example setup.
  1017 
  1018 * New top level command 'normal_form' computes the normal form of a
  1019 term that may contain free variables. For example ``normal_form
  1020 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
  1021 suitable for heavy-duty computations because the functions are
  1022 compiled to ML first.
  1023 
  1024 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1025 25 like -->); output depends on the "iff" print_mode, the default is
  1026 "A = B" (with priority 50).
  1027 
  1028 * Renamed constants in HOL.thy and Orderings.thy:
  1029     op +   ~> HOL.plus_class.plus
  1030     op -   ~> HOL.minus_class.minus
  1031     uminus ~> HOL.minus_class.uminus
  1032     abs    ~> HOL.abs_class.abs
  1033     op *   ~> HOL.times_class.times
  1034     op <   ~> HOL.ord_class.less
  1035     op <=  ~> HOL.ord_class.less_eq
  1036 
  1037 Adaptions may be required in the following cases:
  1038 
  1039 a) User-defined constants using any of the names "plus", "minus", "times",
  1040 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
  1041 may go wrong.
  1042 INCOMPATIBILITY: use more specific names.
  1043 
  1044 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1045 INCOMPATIBILITY: use more specific names.
  1046 
  1047 c) Permutative equations (e.g. "a + b = b + a")
  1048 Since the change of names also changes the order of terms, permutative
  1049 rewrite rules may get applied in a different order. Experience shows that
  1050 this is rarely the case (only two adaptions in the whole Isabelle
  1051 distribution).
  1052 INCOMPATIBILITY: rewrite proofs
  1053 
  1054 d) ML code directly refering to constant names
  1055 This in general only affects hand-written proof tactics, simprocs and so on.
  1056 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
  1057 of const_name ML antiquotations.
  1058 
  1059 * Relations less (<) and less_eq (<=) are also available on type bool.
  1060 Modified syntax to disallow nesting without explicit parentheses,
  1061 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
  1062 
  1063 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1064 
  1065 * Relation composition operator "op O" now has precedence 75 and binds
  1066 stronger than union and intersection. INCOMPATIBILITY.
  1067 
  1068 * The old set interval syntax "{m..n(}" (and relatives) has been
  1069 removed.  Use "{m..<n}" (and relatives) instead.
  1070 
  1071 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1072 "t = s" to False (by simproc "neq_simproc").  For backward
  1073 compatibility this can be disabled by ML "reset use_neq_simproc".
  1074 
  1075 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1076 simp.
  1077 
  1078 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1079 
  1080 * Theorem setsum_mult renamed to setsum_right_distrib.
  1081 
  1082 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1083 ``rule'' method.
  1084 
  1085 * Reimplemented methods ``sat'' and ``satx'', with several
  1086 improvements: goals no longer need to be stated as "<prems> ==>
  1087 False", equivalences (i.e. "=" on type bool) are handled, variable
  1088 names of the form "lit_<n>" are no longer reserved, significant
  1089 speedup.
  1090 
  1091 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1092 zChaff is still supported as well.
  1093 
  1094 * 'inductive' and 'datatype': provide projections of mutual rules,
  1095 bundled as foo_bar.inducts;
  1096 
  1097 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1098 Library.
  1099 
  1100 * Library: moved theory Accessible_Part to main HOL.
  1101 
  1102 * Library: added theory Coinductive_List of potentially infinite lists
  1103 as greatest fixed-point.
  1104 
  1105 * Library: added theory AssocList which implements (finite) maps as
  1106 association lists.
  1107 
  1108 * Added proof method ``evaluation'' for efficiently solving a goal
  1109 (i.e. a boolean expression) by compiling it to ML. The goal is
  1110 "proved" (via an oracle) if it evaluates to True.
  1111 
  1112 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1113 also when invoked by the simplifier.  This results in the simplifier
  1114 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1115 fast_arith_split_limit to 0 to obtain the old behavior.
  1116 
  1117 * Support for hex (0x20) and binary (0b1001) numerals.
  1118 
  1119 * New method: reify eqs (t), where eqs are equations for an
  1120 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1121 parameter, computes a term s::'b and a list xs::'a list and proves the
  1122 theorem I xs s = t. This is also known as reification or quoting. The
  1123 resulting theorem is applied to the subgoal to substitute t with I xs
  1124 s.  If t is omitted, the subgoal itself is reified.
  1125 
  1126 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1127 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1128 where f is supposed to be a computable function (in the sense of code
  1129 generattion). The method uses reify to compute s and xs as above then
  1130 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1131 r and finally gets the theorem t = r, which is again applied to the
  1132 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1133 
  1134 * Reflection: Automatic reification now handels binding, an example
  1135 is available in HOL/ex/ReflectionEx.thy
  1136 
  1137 
  1138 *** HOL-Algebra ***
  1139 
  1140 * Formalisation of ideals and the quotient construction over rings.
  1141 
  1142 * Order and lattice theory no longer based on records.
  1143 INCOMPATIBILITY.
  1144 
  1145 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1146 greatest_closed.  INCOMPATIBILITY.
  1147 
  1148 * Method algebra is now set up via an attribute.  For examples see
  1149 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1150 of algebraic structures.
  1151 
  1152 * Renamed theory CRing to Ring.
  1153 
  1154 
  1155 *** HOL-Complex ***
  1156 
  1157 * Theory Real: new method ferrack implements quantifier elimination
  1158 for linear arithmetic over the reals. The quantifier elimination
  1159 feature is used only for decision, for compatibility with arith. This
  1160 means a goal is either solved or left unchanged, no simplification.
  1161 
  1162 * Hyperreal: Functions root and sqrt are now defined on negative real
  1163 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1164 Nonnegativity side conditions have been removed from many lemmas, so
  1165 that more subgoals may now be solved by simplification; potential
  1166 INCOMPATIBILITY.
  1167 
  1168 * Real: New axiomatic classes formalize real normed vector spaces and
  1169 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1170 and norm :: 'a => real.
  1171 
  1172 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1173 from reals into other types. The overloaded constant Reals :: 'a set
  1174 is now defined as range of_real; potential INCOMPATIBILITY.
  1175 
  1176 * Real: ML code generation is supported now and hence also quickcheck.
  1177 Reals are implemented as arbitrary precision rationals.
  1178 
  1179 * Hyperreal: Several constants that previously worked only for the
  1180 reals have been generalized, so they now work over arbitrary vector
  1181 spaces. Type annotations may need to be added in some cases; potential
  1182 INCOMPATIBILITY.
  1183 
  1184   Infinitesimal  :: ('a::real_normed_vector) star set
  1185   HFinite        :: ('a::real_normed_vector) star set
  1186   HInfinite      :: ('a::real_normed_vector) star set
  1187   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1188   monad          :: ('a::real_normed_vector) star => 'a star set
  1189   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1190   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1191   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1192   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1193   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1194   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1195   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1196   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1197   sgn            :: 'a::real_normed_vector => 'a
  1198   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1199 
  1200 * Complex: Some complex-specific constants are now abbreviations for
  1201 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1202 hnorm.  Other constants have been entirely removed in favor of the
  1203 polymorphic versions (INCOMPATIBILITY):
  1204 
  1205   approx        <-- capprox
  1206   HFinite       <-- CFinite
  1207   HInfinite     <-- CInfinite
  1208   Infinitesimal <-- CInfinitesimal
  1209   monad         <-- cmonad
  1210   galaxy        <-- cgalaxy
  1211   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1212   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1213   (ns)deriv     <-- (ns)cderiv
  1214 
  1215 
  1216 *** ML ***
  1217 
  1218 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1219 
  1220 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1221 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1222 init only required for impure data.  INCOMPATIBILITY: empty really
  1223 need to be empty (no dependencies on theory content!)
  1224 
  1225 * ML within Isar: antiquotations allow to embed statically-checked
  1226 formal entities in the source, referring to the context available at
  1227 compile-time.  For example:
  1228 
  1229 ML {* @{typ "'a => 'b"} *}
  1230 ML {* @{term "%x. x"} *}
  1231 ML {* @{prop "x == y"} *}
  1232 ML {* @{ctyp "'a => 'b"} *}
  1233 ML {* @{cterm "%x. x"} *}
  1234 ML {* @{cprop "x == y"} *}
  1235 ML {* @{thm asm_rl} *}
  1236 ML {* @{thms asm_rl} *}
  1237 ML {* @{const_name c} *}
  1238 ML {* @{const_syntax c} *}
  1239 ML {* @{context} *}
  1240 ML {* @{theory} *}
  1241 ML {* @{theory Pure} *}
  1242 ML {* @{simpset} *}
  1243 ML {* @{claset} *}
  1244 ML {* @{clasimpset} *}
  1245 
  1246 The same works for sources being ``used'' within an Isar context.
  1247 
  1248 * ML in Isar: improved error reporting; extra verbosity with
  1249 Toplevel.debug enabled.
  1250 
  1251 * Pure/library:
  1252 
  1253   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1254   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1255 
  1256 The semantics of "burrow" is: "take a function with *simulatanously*
  1257 transforms a list of value, and apply it *simulatanously* to a list of
  1258 list of values of the appropriate type". Compare this with "map" which
  1259 would *not* apply its argument function simulatanously but in
  1260 sequence; "fold_burrow" has an additional context.
  1261 
  1262 * Pure/library: functions map2 and fold2 with curried syntax for
  1263 simultanous mapping and folding:
  1264 
  1265     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1266     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1267 
  1268 * Pure/library: indexed lists - some functions in the Isabelle library
  1269 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1270 given more convenient names and signatures reminiscent of similar
  1271 functions for alists, tables, etc:
  1272 
  1273   val nth: 'a list -> int -> 'a 
  1274   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1275   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1276 
  1277 Note that fold_index starts counting at index 0, not 1 like foldln
  1278 used to.
  1279 
  1280 * Pure/library: added general ``divide_and_conquer'' combinator on
  1281 lists.
  1282 
  1283 * Pure/General/table.ML: the join operations now works via exceptions
  1284 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1285 admits slightly more efficient complex applications.
  1286 
  1287 * Pure: datatype Context.generic joins theory/Proof.context and
  1288 provides some facilities for code that works in either kind of
  1289 context, notably GenericDataFun for uniform theory and proof data.
  1290 
  1291 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1292 use Context.generic instead of just theory.
  1293 
  1294 * Pure: simplified internal attribute type, which is now always
  1295 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1296 vs. local (Proof.context) attributes have been discontinued, while
  1297 minimizing code duplication.  Thm.rule_attribute and
  1298 Thm.declaration_attribute build canonical attributes; see also
  1299 structure Context for further operations on Context.generic, notably
  1300 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1301 declarations and definitions.
  1302 
  1303 * Pure/kernel: consts certification ignores sort constraints given in
  1304 signature declarations.  (This information is not relevant to the
  1305 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1306 potential INCOMPATIBILITY.
  1307 
  1308 * Pure: axiomatic type classes are now purely definitional, with
  1309 explicit proofs of class axioms and super class relations performed
  1310 internally.  See Pure/axclass.ML for the main internal interfaces --
  1311 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1312 AxClass.axiomatize_class/classrel/arity supercede
  1313 Sign.add_classes/classrel/arities.
  1314 
  1315 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1316 global/local versions on theory vs. Proof.context have been
  1317 discontinued; Attrib.syntax and Method.syntax have been adapted
  1318 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1319 attributes, methods, etc.
  1320 
  1321 * Pure: several functions of signature "... -> theory -> theory * ..."
  1322 have been reoriented to "... -> theory -> ... * theory" in order to
  1323 allow natural usage in combination with the ||>, ||>>, |-> and
  1324 fold_map combinators.
  1325 
  1326 * Pure: official theorem names (closed derivations) and additional
  1327 comments (tags) are now strictly separate.  Name hints -- which are
  1328 maintained as tags -- may be attached any time without affecting the
  1329 derivation.
  1330 
  1331 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1332 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1333 achieve the old behaviour.
  1334 
  1335 * Pure: the "Goal" constant is now called "prop", supporting a
  1336 slightly more general idea of ``protecting'' meta-level rule
  1337 statements.
  1338 
  1339 * Pure: Logic.(un)varify only works in a global context, which is now
  1340 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1341 Logic.legacy_(un)varify as temporary workaround.
  1342 
  1343 * Pure: structure Name provides scalable operations for generating
  1344 internal variable names, notably Name.variants etc.  This replaces
  1345 some popular functions from term.ML:
  1346 
  1347   Term.variant		->  Name.variant
  1348   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1349   Term.invent_names	->  Name.invent_list
  1350 
  1351 Note that low-level renaming rarely occurs in new code -- operations
  1352 from structure Variable are used instead (see below).
  1353 
  1354 * Pure: structure Variable provides fundamental operations for proper
  1355 treatment of fixed/schematic variables in a context.  For example,
  1356 Variable.import introduces fixes for schematics of given facts and
  1357 Variable.export reverses the effect (up to renaming) -- this replaces
  1358 various freeze_thaw operations.
  1359 
  1360 * Pure: structure Goal provides simple interfaces for
  1361 init/conclude/finish and tactical prove operations (replacing former
  1362 Tactic.prove).  Goal.prove is the canonical way to prove results
  1363 within a given context; Goal.prove_global is a degraded version for
  1364 theory level goals, including a global Drule.standard.  Note that
  1365 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1366 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1367 in a locale context).
  1368 
  1369 * Isar: simplified treatment of user-level errors, using exception
  1370 ERROR of string uniformly.  Function error now merely raises ERROR,
  1371 without any side effect on output channels.  The Isar toplevel takes
  1372 care of proper display of ERROR exceptions.  ML code may use plain
  1373 handle/can/try; cat_error may be used to concatenate errors like this:
  1374 
  1375   ... handle ERROR msg => cat_error msg "..."
  1376 
  1377 Toplevel ML code (run directly or through the Isar toplevel) may be
  1378 embedded into the Isar toplevel with exception display/debug like
  1379 this:
  1380 
  1381   Isar.toplevel (fn () => ...)
  1382 
  1383 INCOMPATIBILITY, removed special transform_error facilities, removed
  1384 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1385 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1386 -- use plain ERROR instead.
  1387 
  1388 * Isar: theory setup now has type (theory -> theory), instead of a
  1389 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1390 
  1391 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1392 subject to ProofContext.debug/verbose flags.
  1393 
  1394 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1395 theory before entering a proof state.  Transactions now always see a
  1396 quasi-functional intermediate checkpoint, both in interactive and
  1397 batch mode.
  1398 
  1399 * Simplifier: the simpset of a running simplification process now
  1400 contains a proof context (cf. Simplifier.the_context), which is the
  1401 very context that the initial simpset has been retrieved from (by
  1402 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1403 (solver, looper etc.) may depend on arbitrary proof data.
  1404 
  1405 * Simplifier.inherit_context inherits the proof context (plus the
  1406 local bounds) of the current simplification process; any simproc
  1407 etc. that calls the Simplifier recursively should do this!  Removed
  1408 former Simplifier.inherit_bounds, which is already included here --
  1409 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1410 specify an explicit context using Simplifier.context/theory_context.
  1411 
  1412 * Simplifier/Classical Reasoner: more abstract interfaces
  1413 change_simpset/claset for modifying the simpset/claset reference of a
  1414 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1415 INCOMPATIBILITY.
  1416 
  1417 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1418 "Trueprop" etc.
  1419 
  1420 
  1421 *** System ***
  1422 
  1423 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1424 locations -- now includes the Isabelle version identifier as well.
  1425 This simplifies use of multiple Isabelle installations.
  1426 
  1427 * isabelle-process: option -S (secure mode) disables some critical
  1428 operations, notably runtime compilation and evaluation of ML source
  1429 code.
  1430 
  1431 
  1432 New in Isabelle2005 (October 2005)
  1433 ----------------------------------
  1434 
  1435 *** General ***
  1436 
  1437 * Theory headers: the new header syntax for Isar theories is
  1438 
  1439   theory <name>
  1440   imports <theory1> ... <theoryN>
  1441   uses <file1> ... <fileM>
  1442   begin
  1443 
  1444 where the 'uses' part is optional.  The previous syntax
  1445 
  1446   theory <name> = <theory1> + ... + <theoryN>:
  1447 
  1448 will disappear in the next release.  Use isatool fixheaders to convert
  1449 existing theory files.  Note that there is no change in ancient
  1450 non-Isar theories now, but these will disappear soon.
  1451 
  1452 * Theory loader: parent theories can now also be referred to via
  1453 relative and absolute paths.
  1454 
  1455 * Command 'find_theorems' searches for a list of criteria instead of a
  1456 list of constants. Known criteria are: intro, elim, dest, name:string,
  1457 simp:term, and any term. Criteria can be preceded by '-' to select
  1458 theorems that do not match. Intro, elim, dest select theorems that
  1459 match the current goal, name:s selects theorems whose fully qualified
  1460 name contain s, and simp:term selects all simplification rules whose
  1461 lhs match term.  Any other term is interpreted as pattern and selects
  1462 all theorems matching the pattern. Available in ProofGeneral under
  1463 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1464 
  1465   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1466 
  1467 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1468 matching the current goal as introduction rule and not having "HOL."
  1469 in their name (i.e. not being defined in theory HOL).
  1470 
  1471 * Command 'thms_containing' has been discontinued in favour of
  1472 'find_theorems'; INCOMPATIBILITY.
  1473 
  1474 * Communication with Proof General is now 8bit clean, which means that
  1475 Unicode text in UTF-8 encoding may be used within theory texts (both
  1476 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1477 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1478 
  1479   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1480   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1481 
  1482 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1483 Classical Reasoner.  Typical big applications run around 2 times
  1484 faster.
  1485 
  1486 
  1487 *** Document preparation ***
  1488 
  1489 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1490 of raw sources.  Only those symbols that do not require additional
  1491 LaTeX packages (depending on comments in isabellesym.sty) are
  1492 displayed properly, everything else is left verbatim.  isatool display
  1493 and isatool print are used as front ends (these are subject to the
  1494 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1495 
  1496 * Command tags control specific markup of certain regions of text,
  1497 notably folding and hiding.  Predefined tags include "theory" (for
  1498 theory begin and end), "proof" for proof commands, and "ML" for
  1499 commands involving ML code; the additional tags "visible" and
  1500 "invisible" are unused by default.  Users may give explicit tag
  1501 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1502 interpretation of tags is determined by the LaTeX job during document
  1503 preparation: see option -V of isatool usedir, or options -n and -t of
  1504 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1505 \isadroptag.
  1506 
  1507 Several document versions may be produced at the same time via isatool
  1508 usedir (the generated index.html will link all of them).  Typical
  1509 specifications include ''-V document=theory,proof,ML'' to present
  1510 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1511 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1512 these parts without any formal replacement text.  The Isabelle site
  1513 default settings produce ''document'' and ''outline'' versions as
  1514 specified above.
  1515 
  1516 * Several new antiquotations:
  1517 
  1518   @{term_type term} prints a term with its type annotated;
  1519 
  1520   @{typeof term} prints the type of a term;
  1521 
  1522   @{const const} is the same as @{term const}, but checks that the
  1523   argument is a known logical constant;
  1524 
  1525   @{term_style style term} and @{thm_style style thm} print a term or
  1526   theorem applying a "style" to it
  1527 
  1528   @{ML text}
  1529 
  1530 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1531 definitions, equations, inequations etc., 'concl' printing only the
  1532 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1533 to print the specified premise.  TermStyle.add_style provides an ML
  1534 interface for introducing further styles.  See also the "LaTeX Sugar"
  1535 document practical applications.  The ML antiquotation prints
  1536 type-checked ML expressions verbatim.
  1537 
  1538 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1539 and 'text' support optional locale specification '(in loc)', which
  1540 specifies the default context for interpreting antiquotations.  For
  1541 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1542 
  1543 * Option 'locale=NAME' of antiquotations specifies an alternative
  1544 context interpreting the subsequent argument.  For example: @{thm
  1545 [locale=lattice] inf_assoc}.
  1546 
  1547 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1548 a proof context.
  1549 
  1550 * Proper output of antiquotations for theory commands involving a
  1551 proof context (such as 'locale' or 'theorem (in loc) ...').
  1552 
  1553 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1554 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1555 
  1556 * isatool usedir: new option -C (default true) controls whether option
  1557 -D should include a copy of the original document directory; -C false
  1558 prevents unwanted effects such as copying of administrative CVS data.
  1559 
  1560 
  1561 *** Pure ***
  1562 
  1563 * Considerably improved version of 'constdefs' command.  Now performs
  1564 automatic type-inference of declared constants; additional support for
  1565 local structure declarations (cf. locales and HOL records), see also
  1566 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1567 sequential dependencies of definitions within a single 'constdefs'
  1568 section; moreover, the declared name needs to be an identifier.  If
  1569 all fails, consider to fall back on 'consts' and 'defs' separately.
  1570 
  1571 * Improved indexed syntax and implicit structures.  First of all,
  1572 indexed syntax provides a notational device for subscripted
  1573 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1574 expressions.  Secondly, in a local context with structure
  1575 declarations, number indexes \<^sub>n or the empty index (default
  1576 number 1) refer to a certain fixed variable implicitly; option
  1577 show_structs controls printing of implicit structures.  Typical
  1578 applications of these concepts involve record types and locales.
  1579 
  1580 * New command 'no_syntax' removes grammar declarations (and
  1581 translations) resulting from the given syntax specification, which is
  1582 interpreted in the same manner as for the 'syntax' command.
  1583 
  1584 * 'Advanced' translation functions (parse_translation etc.) may depend
  1585 on the signature of the theory context being presently used for
  1586 parsing/printing, see also isar-ref manual.
  1587 
  1588 * Improved 'oracle' command provides a type-safe interface to turn an
  1589 ML expression of type theory -> T -> term into a primitive rule of
  1590 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1591 is already included here); see also FOL/ex/IffExample.thy;
  1592 INCOMPATIBILITY.
  1593 
  1594 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1595 before); "cI" is no longer bound, use "c.intro" instead.
  1596 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1597 axclasses vs. locales.
  1598 
  1599 * Improved internal renaming of symbolic identifiers -- attach primes
  1600 instead of base 26 numbers.
  1601 
  1602 * New flag show_question_marks controls printing of leading question
  1603 marks in schematic variable names.
  1604 
  1605 * In schematic variable names, *any* symbol following \<^isub> or
  1606 \<^isup> is now treated as part of the base name.  For example, the
  1607 following works without printing of awkward ".0" indexes:
  1608 
  1609   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1610     by simp
  1611 
  1612 * Inner syntax includes (*(*nested*) comments*).
  1613 
  1614 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1615 annotations as "(00...)".
  1616 
  1617 * Clear separation of logical types and nonterminals, where the latter
  1618 may only occur in 'syntax' specifications or type abbreviations.
  1619 Before that distinction was only partially implemented via type class
  1620 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1621 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1622 exotic syntax specifications may require further adaption
  1623 (e.g. Cube/Cube.thy).
  1624 
  1625 * Removed obsolete type class "logic", use the top sort {} instead.
  1626 Note that non-logical types should be declared as 'nonterminals'
  1627 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1628 specifications.
  1629 
  1630 * Attributes 'induct' and 'cases': type or set names may now be
  1631 locally fixed variables as well.
  1632 
  1633 * Simplifier: can now control the depth to which conditional rewriting
  1634 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1635 Limit.
  1636 
  1637 * Simplifier: simplification procedures may now take the current
  1638 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1639 interface), which is very useful for calling the Simplifier
  1640 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1641 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1642 low-level mk_simproc no longer applies Logic.varify internally, to
  1643 allow for use in a context of fixed variables.
  1644 
  1645 * thin_tac now works even if the assumption being deleted contains !!
  1646 or ==>.  More generally, erule now works even if the major premise of
  1647 the elimination rule contains !! or ==>.
  1648 
  1649 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1650 
  1651 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1652 from Pure, which contains all common declarations already.  Both
  1653 theories are defined via plain Isabelle/Isar .thy files.
  1654 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1655 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1656 use isatool fixcpure to adapt your theory and ML sources.
  1657 
  1658 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1659 selections of theorems in named facts via index ranges.
  1660 
  1661 * 'print_theorems': in theory mode, really print the difference
  1662 wrt. the last state (works for interactive theory development only),
  1663 in proof mode print all local facts (cf. 'print_facts');
  1664 
  1665 * 'hide': option '(open)' hides only base names.
  1666 
  1667 * More efficient treatment of intermediate checkpoints in interactive
  1668 theory development.
  1669 
  1670 * Code generator is now invoked via code_module (incremental code
  1671 generation) and code_library (modular code generation, ML structures
  1672 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1673 must be quoted when used as identifiers.
  1674 
  1675 * New 'value' command for reading, evaluating and printing terms using
  1676 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1677 quoted when used as identifier.
  1678 
  1679 
  1680 *** Locales ***
  1681 
  1682 * New commands for the interpretation of locale expressions in
  1683 theories (1), locales (2) and proof contexts (3).  These generate
  1684 proof obligations from the expression specification.  After the
  1685 obligations have been discharged, theorems of the expression are added
  1686 to the theory, target locale or proof context.  The synopsis of the
  1687 commands is a follows:
  1688 
  1689   (1) interpretation expr inst
  1690   (2) interpretation target < expr
  1691   (3) interpret expr inst
  1692 
  1693 Interpretation in theories and proof contexts require a parameter
  1694 instantiation of terms from the current context.  This is applied to
  1695 specifications and theorems of the interpreted expression.
  1696 Interpretation in locales only permits parameter renaming through the
  1697 locale expression.  Interpretation is smart in that interpretations
  1698 that are active already do not occur in proof obligations, neither are
  1699 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1700 inspect active interpretations of a particular locale.  For details,
  1701 see the Isar Reference manual.  Examples can be found in
  1702 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1703 
  1704 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1705 'interpret' instead.
  1706 
  1707 * New context element 'constrains' for adding type constraints to
  1708 parameters.
  1709 
  1710 * Context expressions: renaming of parameters with syntax
  1711 redeclaration.
  1712 
  1713 * Locale declaration: 'includes' disallowed.
  1714 
  1715 * Proper static binding of attribute syntax -- i.e. types / terms /
  1716 facts mentioned as arguments are always those of the locale definition
  1717 context, independently of the context of later invocations.  Moreover,
  1718 locale operations (renaming and type / term instantiation) are applied
  1719 to attribute arguments as expected.
  1720 
  1721 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1722 actual attributes; rare situations may require Attrib.attribute to
  1723 embed those attributes into Attrib.src that lack concrete syntax.
  1724 Attribute implementations need to cooperate properly with the static
  1725 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1726 Attrib.XXX_thm etc. already do the right thing without further
  1727 intervention.  Only unusual applications -- such as "where" or "of"
  1728 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1729 on the context and the facts involved -- may have to assign parsed
  1730 values to argument tokens explicitly.
  1731 
  1732 * Changed parameter management in theorem generation for long goal
  1733 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1734 theorem statement in rare situations.
  1735 
  1736 * Locale inspection command 'print_locale' omits notes elements.  Use
  1737 'print_locale!' to have them included in the output.
  1738 
  1739 
  1740 *** Provers ***
  1741 
  1742 * Provers/hypsubst.ML: improved version of the subst method, for
  1743 single-step rewriting: it now works in bound variable contexts. New is
  1744 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1745 rewrite a different subterm than the original subst method, which is
  1746 still available as 'simplesubst'.
  1747 
  1748 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1749 and quasi orders.
  1750 
  1751 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1752 reflexive-transitive closure of relations.
  1753 
  1754 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1755 limit (previously hard-coded with a value of 20) user-definable.
  1756 
  1757 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1758 is peformed already.  Object-logics merely need to finish their
  1759 initial simpset configuration as before.  INCOMPATIBILITY.
  1760 
  1761 
  1762 *** HOL ***
  1763 
  1764 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1765 
  1766   syntax (epsilon)
  1767     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1768 
  1769 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1770 and x-symbol; use option '-m epsilon' to get it actually printed.
  1771 Moreover, the mathematically important symbolic identifier \<epsilon>
  1772 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1773 
  1774 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1775 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1776 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1777 support corresponding Isar calculations.
  1778 
  1779 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1780 instead of ":".
  1781 
  1782 * theory SetInterval: changed the syntax for open intervals:
  1783 
  1784   Old       New
  1785   {..n(}    {..<n}
  1786   {)n..}    {n<..}
  1787   {m..n(}   {m..<n}
  1788   {)m..n}   {m<..n}
  1789   {)m..n(}  {m<..<n}
  1790 
  1791 The old syntax is still supported but will disappear in the next
  1792 release.  For conversion use the following Emacs search and replace
  1793 patterns (these are not perfect but work quite well):
  1794 
  1795   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1796   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1797 
  1798 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1799 equalities in commutative rings; method 'algebra' provides a generic
  1800 interface.
  1801 
  1802 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1803 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1804 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1805 be a tuple pattern.
  1806 
  1807 Some new syntax forms are available:
  1808 
  1809   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1810   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1811   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1812   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1813 
  1814 The latter form "\<Sum>x < k. e" used to be based on a separate
  1815 function "Summation", which has been discontinued.
  1816 
  1817 * theory Finite_Set: in structured induction proofs, the insert case
  1818 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1819 (insert F x)'.
  1820 
  1821 * The 'refute' command has been extended to support a much larger
  1822 fragment of HOL, including axiomatic type classes, constdefs and
  1823 typedefs, inductive datatypes and recursion.
  1824 
  1825 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1826 Requires zChaff with proof generation to be installed.  See
  1827 HOL/ex/SAT_Examples.thy for examples.
  1828 
  1829 * Datatype induction via method 'induct' now preserves the name of the
  1830 induction variable. For example, when proving P(xs::'a list) by
  1831 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1832 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1833 in unstructured proof scripts.
  1834 
  1835 * Reworked implementation of records.  Improved scalability for
  1836 records with many fields, avoiding performance problems for type
  1837 inference. Records are no longer composed of nested field types, but
  1838 of nested extension types. Therefore the record type only grows linear
  1839 in the number of extensions and not in the number of fields.  The
  1840 top-level (users) view on records is preserved.  Potential
  1841 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1842 old record representation. The type generated for a record is called
  1843 <record_name>_ext_type.
  1844 
  1845 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1846 proofs triggered by a record definition or a simproc (if
  1847 quick_and_dirty is enabled).  Definitions of large records can take
  1848 quite long.
  1849 
  1850 New simproc record_upd_simproc for simplification of multiple record
  1851 updates enabled by default.  Moreover, trivial updates are also
  1852 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1853 occasionally, since simplification is more powerful by default.
  1854 
  1855 * typedef: proper support for polymorphic sets, which contain extra
  1856 type-variables in the term.
  1857 
  1858 * Simplifier: automatically reasons about transitivity chains
  1859 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1860 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1861 old proofs break occasionally as simplification may now solve more
  1862 goals than previously.
  1863 
  1864 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1865 present.  Works for all partial orders (class "order"), in particular
  1866 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1867 just like y <= x.
  1868 
  1869 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1870 bound variable or a constant then the let is unfolded.  Otherwise
  1871 first a is simplified to b, and then f b is simplified to g. If
  1872 possible we abstract b from g arriving at "let x = b in h x",
  1873 otherwise we unfold the let and arrive at g.  The simproc can be
  1874 enabled/disabled by the reference use_let_simproc.  Potential
  1875 INCOMPATIBILITY since simplification is more powerful by default.
  1876 
  1877 * Classical reasoning: the meson method now accepts theorems as arguments.
  1878 
  1879 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1880 jobs to provide advice on the provability of subgoals.
  1881 
  1882 * Theory OrderedGroup and Ring_and_Field: various additions and
  1883 improvements to faciliate calculations involving equalities and
  1884 inequalities.
  1885 
  1886 The following theorems have been eliminated or modified
  1887 (INCOMPATIBILITY):
  1888 
  1889   abs_eq             now named abs_of_nonneg
  1890   abs_of_ge_0        now named abs_of_nonneg
  1891   abs_minus_eq       now named abs_of_nonpos
  1892   imp_abs_id         now named abs_of_nonneg
  1893   imp_abs_neg_id     now named abs_of_nonpos
  1894   mult_pos           now named mult_pos_pos
  1895   mult_pos_le        now named mult_nonneg_nonneg
  1896   mult_pos_neg_le    now named mult_nonneg_nonpos
  1897   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1898   mult_neg           now named mult_neg_neg
  1899   mult_neg_le        now named mult_nonpos_nonpos
  1900 
  1901 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1902      
  1903      zero_le_square
  1904      not_square_less_zero 
  1905 
  1906   The following lemmas have been deleted from Real/RealPow:
  1907   
  1908      realpow_zero_zero
  1909      realpow_two
  1910      realpow_less
  1911      zero_le_power
  1912      realpow_two_le
  1913      abs_realpow_two
  1914      realpow_two_abs     
  1915 
  1916 * Theory Parity: added rules for simplifying exponents.
  1917 
  1918 * Theory List:
  1919 
  1920 The following theorems have been eliminated or modified
  1921 (INCOMPATIBILITY):
  1922 
  1923   list_all_Nil       now named list_all.simps(1)
  1924   list_all_Cons      now named list_all.simps(2)
  1925   list_all_conv      now named list_all_iff
  1926   set_mem_eq         now named mem_iff
  1927 
  1928 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1929 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1930 
  1931 
  1932 *** HOL-Complex ***
  1933 
  1934 * Theory RealDef: better support for embedding natural numbers and
  1935 integers in the reals.
  1936 
  1937 The following theorems have been eliminated or modified
  1938 (INCOMPATIBILITY):
  1939 
  1940   exp_ge_add_one_self  now requires no hypotheses
  1941   real_of_int_add      reversed direction of equality (use [symmetric])
  1942   real_of_int_minus    reversed direction of equality (use [symmetric])
  1943   real_of_int_diff     reversed direction of equality (use [symmetric])
  1944   real_of_int_mult     reversed direction of equality (use [symmetric])
  1945 
  1946 * Theory RComplete: expanded support for floor and ceiling functions.
  1947 
  1948 * Theory Ln is new, with properties of the natural logarithm
  1949 
  1950 * Hyperreal: There is a new type constructor "star" for making
  1951 nonstandard types.  The old type names are now type synonyms:
  1952 
  1953   hypreal = real star
  1954   hypnat = nat star
  1955   hcomplex = complex star
  1956 
  1957 * Hyperreal: Many groups of similarly-defined constants have been
  1958 replaced by polymorphic versions (INCOMPATIBILITY):
  1959 
  1960   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1961 
  1962   starset      <-- starsetNat, starsetC
  1963   *s*          <-- *sNat*, *sc*
  1964   starset_n    <-- starsetNat_n, starsetC_n
  1965   *sn*         <-- *sNatn*, *scn*
  1966   InternalSets <-- InternalNatSets, InternalCSets
  1967 
  1968   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1969   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1970   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1971   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1972   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1973 
  1974 * Hyperreal: Many type-specific theorems have been removed in favor of
  1975 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1976 
  1977   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1978   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1979   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1980   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1981   right_minus <-- hypreal_add_minus
  1982   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1983   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1984   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1985   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1986   mult_1_right <-- hcomplex_mult_one_right
  1987   mult_zero_left <-- hcomplex_mult_zero_left
  1988   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1989   right_distrib <-- hypnat_add_mult_distrib2
  1990   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1991   right_inverse <-- hypreal_mult_inverse
  1992   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1993   order_refl <-- {hypreal,hypnat}_le_refl
  1994   order_trans <-- {hypreal,hypnat}_le_trans
  1995   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1996   order_less_le <-- {hypreal,hypnat}_less_le
  1997   linorder_linear <-- {hypreal,hypnat}_le_linear
  1998   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1999   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2000   add_nonneg_nonneg <-- hypreal_le_add_order
  2001 
  2002 * Hyperreal: Separate theorems having to do with type-specific
  2003 versions of constants have been merged into theorems that apply to the
  2004 new polymorphic constants (INCOMPATIBILITY):
  2005 
  2006   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2007   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2008   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2009   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2010   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2011   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2012   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2013   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2014   STAR_diff <-- {STAR,STARC}_diff
  2015   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2016     STARC_hcomplex_of_complex}_image_subset
  2017   starset_n_Un <-- starset{Nat,C}_n_Un
  2018   starset_n_Int <-- starset{Nat,C}_n_Int
  2019   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2020   starset_n_diff <-- starset{Nat,C}_n_diff
  2021   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2022   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2023   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2024   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2025   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2026   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2027   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2028   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2029   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2030   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2031   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2032   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2033   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2034   starfun_diff <-- starfun{C,RC,CR}_diff
  2035   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2036   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2037   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2038   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2039   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2040   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2041   starfun_Id <-- starfunC_Id
  2042   starfun_approx <-- starfun{Nat,CR}_approx
  2043   starfun_capprox <-- starfun{C,RC}_capprox
  2044   starfun_abs <-- starfunNat_rabs
  2045   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2046   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2047   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2048   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2049   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2050   starfun_add_approx <-- starfunCR_add_approx
  2051   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2052   starfun_divide <-- starfun{C,CR,RC}_divide
  2053   starfun_n <-- starfun{Nat,C}_n
  2054   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2055   starfun_n_add <-- starfun{Nat,C}_n_add
  2056   starfun_n_add_minus <-- starfunNat_n_add_minus
  2057   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2058   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2059   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2060 
  2061   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2062   star_n_minus <-- {hypreal,hcomplex}_minus
  2063   star_n_diff <-- {hypreal,hcomplex}_diff
  2064   star_n_mult <-- {hypreal,hcomplex}_mult
  2065   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2066   star_n_le <-- {hypreal,hypnat}_le
  2067   star_n_less <-- {hypreal,hypnat}_less
  2068   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2069   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2070   star_n_abs <-- hypreal_hrabs
  2071   star_n_divide <-- hcomplex_divide
  2072 
  2073   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2074   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2075   star_of_diff <-- hypreal_of_real_diff
  2076   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2077   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2078   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2079   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2080   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2081   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2082   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2083   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2084   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2085   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2086   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2087   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2088   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2089   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2090   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2091   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2092   star_of_power <-- hypreal_of_real_power
  2093   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2094 
  2095 * Hyperreal: new method "transfer" that implements the transfer
  2096 principle of nonstandard analysis. With a subgoal that mentions
  2097 nonstandard types like "'a star", the command "apply transfer"
  2098 replaces it with an equivalent one that mentions only standard types.
  2099 To be successful, all free variables must have standard types; non-
  2100 standard variables must have explicit universal quantifiers.
  2101 
  2102 * Hyperreal: A theory of Taylor series.
  2103 
  2104 
  2105 *** HOLCF ***
  2106 
  2107 * Discontinued special version of 'constdefs' (which used to support
  2108 continuous functions) in favor of the general Pure one with full
  2109 type-inference.
  2110 
  2111 * New simplification procedure for solving continuity conditions; it
  2112 is much faster on terms with many nested lambda abstractions (cubic
  2113 instead of exponential time).
  2114 
  2115 * New syntax for domain package: selector names are now optional.
  2116 Parentheses should be omitted unless argument is lazy, for example:
  2117 
  2118   domain 'a stream = cons "'a" (lazy "'a stream")
  2119 
  2120 * New command 'fixrec' for defining recursive functions with pattern
  2121 matching; defining multiple functions with mutual recursion is also
  2122 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2123 sinr, or any data constructor defined by the domain package. The given
  2124 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2125 syntax and examples.
  2126 
  2127 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2128 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2129 but the proof obligation additionally includes an admissibility
  2130 requirement. The packages generate instances of class cpo or pcpo,
  2131 with continuity and strictness theorems for Rep and Abs.
  2132 
  2133 * HOLCF: Many theorems have been renamed according to a more standard naming
  2134 scheme (INCOMPATIBILITY):
  2135 
  2136   foo_inject:  "foo$x = foo$y ==> x = y"
  2137   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2138   foo_less:    "(foo$x << foo$y) = (x << y)"
  2139   foo_strict:  "foo$UU = UU"
  2140   foo_defined: "... ==> foo$x ~= UU"
  2141   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2142 
  2143 
  2144 *** ZF ***
  2145 
  2146 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2147 including the First Isomorphism Theorem (on quotienting by the kernel
  2148 of a homomorphism).
  2149 
  2150 * ZF/Simplifier: install second copy of type solver that actually
  2151 makes use of TC rules declared to Isar proof contexts (or locales);
  2152 the old version is still required for ML proof scripts.
  2153 
  2154 
  2155 *** Cube ***
  2156 
  2157 * Converted to Isar theory format; use locales instead of axiomatic
  2158 theories.
  2159 
  2160 
  2161 *** ML ***
  2162 
  2163 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2164 for ||>, ||>>, |>>,
  2165 
  2166 * Pure/library.ML no longer defines its own option datatype, but uses
  2167 that of the SML basis, which has constructors NONE and SOME instead of
  2168 None and Some, as well as exception Option.Option instead of OPTION.
  2169 The functions the, if_none, is_some, is_none have been adapted
  2170 accordingly, while Option.map replaces apsome.
  2171 
  2172 * Pure/library.ML: the exception LIST has been given up in favour of
  2173 the standard exceptions Empty and Subscript, as well as
  2174 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2175 superceded by the standard hd and tl functions etc.
  2176 
  2177 A number of basic list functions are no longer exported to the ML
  2178 toplevel, as they are variants of predefined functions.  The following
  2179 suggests how one can translate existing code:
  2180 
  2181     rev_append xs ys = List.revAppend (xs, ys)
  2182     nth_elem (i, xs) = List.nth (xs, i)
  2183     last_elem xs = List.last xs
  2184     flat xss = List.concat xss
  2185     seq fs = List.app fs
  2186     partition P xs = List.partition P xs
  2187     mapfilter f xs = List.mapPartial f xs
  2188 
  2189 * Pure/library.ML: several combinators for linear functional
  2190 transformations, notably reverse application and composition:
  2191 
  2192   x |> f                f #> g
  2193   (x, y) |-> f          f #-> g
  2194 
  2195 * Pure/library.ML: introduced/changed precedence of infix operators:
  2196 
  2197   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2198   infix 2 ?;
  2199   infix 3 o oo ooo oooo;
  2200   infix 4 ~~ upto downto;
  2201 
  2202 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2203 infix operators.
  2204 
  2205 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2206 fold_map support linear functional transformations and nesting.  For
  2207 example:
  2208 
  2209   fold f [x1, ..., xN] y =
  2210     y |> f x1 |> ... |> f xN
  2211 
  2212   (fold o fold) f [xs1, ..., xsN] y =
  2213     y |> fold f xs1 |> ... |> fold f xsN
  2214 
  2215   fold f [x1, ..., xN] =
  2216     f x1 #> ... #> f xN
  2217 
  2218   (fold o fold) f [xs1, ..., xsN] =
  2219     fold f xs1 #> ... #> fold f xsN
  2220 
  2221 * Pure/library.ML: the following selectors on type 'a option are
  2222 available:
  2223 
  2224   the:               'a option -> 'a  (*partial*)
  2225   these:             'a option -> 'a  where 'a = 'b list
  2226   the_default: 'a -> 'a option -> 'a
  2227   the_list:          'a option -> 'a list
  2228 
  2229 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2230 basic operations for association lists, following natural argument
  2231 order; moreover the explicit equality predicate passed here avoids
  2232 potentially expensive polymorphic runtime equality checks.
  2233 The old functions may be expressed as follows:
  2234 
  2235   assoc = uncurry (AList.lookup (op =))
  2236   assocs = these oo AList.lookup (op =)
  2237   overwrite = uncurry (AList.update (op =)) o swap
  2238 
  2239 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2240 
  2241   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2242   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2243 
  2244 replacing make_keylist and keyfilter (occassionally used)
  2245 Naive rewrites:
  2246 
  2247   make_keylist = AList.make
  2248   keyfilter = AList.find (op =)
  2249 
  2250 * eq_fst and eq_snd now take explicit equality parameter, thus
  2251   avoiding eqtypes. Naive rewrites:
  2252 
  2253     eq_fst = eq_fst (op =)
  2254     eq_snd = eq_snd (op =)
  2255 
  2256 * Removed deprecated apl and apr (rarely used).
  2257   Naive rewrites:
  2258 
  2259     apl (n, op) =>>= curry op n
  2260     apr (op, m) =>>= fn n => op (n, m)
  2261 
  2262 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2263 provides a reasonably efficient light-weight implementation of sets as
  2264 lists.
  2265 
  2266 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2267 few new operations; existing lookup and update are now curried to
  2268 follow natural argument order (for use with fold etc.);
  2269 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2270 
  2271 * Pure/General: output via the Isabelle channels of
  2272 writeln/warning/error etc. is now passed through Output.output, with a
  2273 hook for arbitrary transformations depending on the print_mode
  2274 (cf. Output.add_mode -- the first active mode that provides a output
  2275 function wins).  Already formatted output may be embedded into further
  2276 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2277 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2278 accommodate easy composition of diagnostic messages etc.  Programmers
  2279 rarely need to care about Output.output or Output.raw at all, with
  2280 some notable exceptions: Output.output is required when bypassing the
  2281 standard channels (writeln etc.), or in token translations to produce
  2282 properly formatted results; Output.raw is required when capturing
  2283 already output material that will eventually be presented to the user
  2284 a second time.  For the default print mode, both Output.output and
  2285 Output.raw have no effect.
  2286 
  2287 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2288 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2289 cumulative results are displayed at the end of a batch session.
  2290 
  2291 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2292 replaced by File.platform_path and File.shell_path (with appropriate
  2293 hooks).  This provides a clean interface for unusual systems where the
  2294 internal and external process view of file names are different.
  2295 
  2296 * Pure: more efficient orders for basic syntactic entities: added
  2297 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2298 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2299 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2300 orders now -- potential INCOMPATIBILITY for code that depends on a
  2301 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2302 Library.sort_strings on result).
  2303 
  2304 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2305 fold_types traverse types/terms from left to right, observing natural
  2306 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2307 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2308 
  2309 * Pure: name spaces have been refined, with significant changes of the
  2310 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2311 to extern(_table).  The plain name entry path is superceded by a
  2312 general 'naming' context, which also includes the 'policy' to produce
  2313 a fully qualified name and external accesses of a fully qualified
  2314 name; NameSpace.extend is superceded by context dependent
  2315 Sign.declare_name.  Several theory and proof context operations modify
  2316 the naming context.  Especially note Theory.restore_naming and
  2317 ProofContext.restore_naming to get back to a sane state; note that
  2318 Theory.add_path is no longer sufficient to recover from
  2319 Theory.absolute_path in particular.
  2320 
  2321 * Pure: new flags short_names (default false) and unique_names
  2322 (default true) for controlling output of qualified names.  If
  2323 short_names is set, names are printed unqualified.  If unique_names is
  2324 reset, the name prefix is reduced to the minimum required to achieve
  2325 the original result when interning again, even if there is an overlap
  2326 with earlier declarations.
  2327 
  2328 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2329 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2330 (useful for printing error messages).  INCOMPATIBILITY.
  2331 
  2332 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2333 Theory.theory are now identified, referring to the universal
  2334 Context.theory (see Pure/context.ML).  Actual signature and theory
  2335 content is managed as theory data.  The old code and interfaces were
  2336 spread over many files and structures; the new arrangement introduces
  2337 considerable INCOMPATIBILITY to gain more clarity:
  2338 
  2339   Context -- theory management operations (name, identity, inclusion,
  2340     parents, ancestors, merge, etc.), plus generic theory data;
  2341 
  2342   Sign -- logical signature and syntax operations (declaring consts,
  2343     types, etc.), plus certify/read for common entities;
  2344 
  2345   Theory -- logical theory operations (stating axioms, definitions,
  2346     oracles), plus a copy of logical signature operations (consts,
  2347     types, etc.); also a few basic management operations (Theory.copy,
  2348     Theory.merge, etc.)
  2349 
  2350 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2351 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2352 for convenience -- they merely return the theory.
  2353 
  2354 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2355 
  2356 * Pure: the Isar proof context type is already defined early in Pure
  2357 as Context.proof (note that ProofContext.context and Proof.context are
  2358 aliases, where the latter is the preferred name).  This enables other
  2359 Isabelle components to refer to that type even before Isar is present.
  2360 
  2361 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2362 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2363 any of these kinds.  For example, Sign.intern typeK is now
  2364 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2365 Theory.hide_types.  Also note that former
  2366 Theory.hide_classes/types/consts are now
  2367 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2368 internalize their arguments!  INCOMPATIBILITY.
  2369 
  2370 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2371 datatype thmref (with constructors Name and NameSelection) instead of
  2372 plain string -- INCOMPATIBILITY;
  2373 
  2374 * Pure: cases produced by proof methods specify options, where NONE
  2375 means to remove case bindings -- INCOMPATIBILITY in
  2376 (RAW_)METHOD_CASES.
  2377 
  2378 * Pure: the following operations retrieve axioms or theorems from a
  2379 theory node or theory hierarchy, respectively:
  2380 
  2381   Theory.axioms_of: theory -> (string * term) list
  2382   Theory.all_axioms_of: theory -> (string * term) list
  2383   PureThy.thms_of: theory -> (string * thm) list
  2384   PureThy.all_thms_of: theory -> (string * thm) list
  2385 
  2386 * Pure: print_tac now outputs the goal through the trace channel.
  2387 
  2388 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2389 Reference Toplevel.debug (default false) controls detailed printing
  2390 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2391 controls execution profiling -- set to 1 for time and 2 for space
  2392 (both increase the runtime).
  2393 
  2394 * Isar session: The initial use of ROOT.ML is now always timed,
  2395 i.e. the log will show the actual process times, in contrast to the
  2396 elapsed wall-clock time that the outer shell wrapper produces.
  2397 
  2398 * Simplifier: improved handling of bound variables (nameless
  2399 representation, avoid allocating new strings).  Simprocs that invoke
  2400 the Simplifier recursively should use Simplifier.inherit_bounds to
  2401 avoid local name clashes.  Failure to do so produces warnings
  2402 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2403 for further details.
  2404 
  2405 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2406 bindings for all theorems stored within a given theory; this may help
  2407 in porting non-Isar theories to Isar ones, while keeping ML proof
  2408 scripts for the time being.
  2409 
  2410 * ML operator HTML.with_charset specifies the charset begin used for
  2411 generated HTML files.  For example:
  2412 
  2413   HTML.with_charset "utf-8" use_thy "Hebrew";
  2414   HTML.with_charset "utf-8" use_thy "Chinese";
  2415 
  2416 
  2417 *** System ***
  2418 
  2419 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2420 isabelle, isatool etc.).
  2421 
  2422 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2423 isatool doc, isatool mkdir, display_drafts etc.).
  2424 
  2425 * isatool usedir: option -f allows specification of the ML file to be
  2426 used by Isabelle; default is ROOT.ML.
  2427 
  2428 * New isatool version outputs the version identifier of the Isabelle
  2429 distribution being used.
  2430 
  2431 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2432 (containing Boolean satisfiability problems) into Isabelle/HOL
  2433 theories.
  2434 
  2435 
  2436 
  2437 New in Isabelle2004 (April 2004)
  2438 --------------------------------
  2439 
  2440 *** General ***
  2441 
  2442 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2443   Replaces linorder.ML.
  2444 
  2445 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2446   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2447   (\<a>...\<z>), are now considered normal letters, and can therefore
  2448   be used anywhere where an ASCII letter (a...zA...Z) has until
  2449   now. COMPATIBILITY: This obviously changes the parsing of some
  2450   terms, especially where a symbol has been used as a binder, say
  2451   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2452   as an identifier.  Fix it by inserting a space around former
  2453   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2454   existing theory and ML files.
  2455 
  2456 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2457 
  2458 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2459   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2460   a normal (but invisible) letter. For multiple letter subscripts repeat
  2461   \<^isub> like this: x\<^isub>1\<^isub>2.
  2462 
  2463 * Pure: There are now sub-/superscripts that can span more than one
  2464   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2465   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2466   superscript. The new control characters are not identifier parts.
  2467 
  2468 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2469   content of "..." to the latex file instead of \isacntrl... . The "..."
  2470   may consist of any printable characters excluding the end bracket >.
  2471 
  2472 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2473   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2474   declare constants "final", which prevents their being given a definition
  2475   later.  It is useful for constants whose behaviour is fixed axiomatically
  2476   rather than definitionally, such as the meta-logic connectives.
  2477 
  2478 * Pure: 'instance' now handles general arities with general sorts
  2479   (i.e. intersections of classes),
  2480 
  2481 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2482   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2483   It can be changed to alter the colors/layout of generated pages.
  2484 
  2485 
  2486 *** Isar ***
  2487 
  2488 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2489   cut_tac, subgoal_tac and thin_tac:
  2490   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2491     locales are no longer forced to write Isar proof scripts.
  2492     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2493     emulations.
  2494   - INCOMPATIBILITY: names of variables to be instantiated may no
  2495     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2496     This is consistent with the instantiation attribute "where".
  2497 
  2498 * Attributes "where" and "of":
  2499   - Now take type variables of instantiated theorem into account when reading
  2500     the instantiation string.  This fixes a bug that caused instantiated
  2501     theorems to have too special types in some circumstances.
  2502   - "where" permits explicit instantiations of type variables.
  2503 
  2504 * Calculation commands "moreover" and "also" no longer interfere with
  2505   current facts ("this"), admitting arbitrary combinations with "then"
  2506   and derived forms.
  2507 
  2508 * Locales:
  2509   - Goal statements involving the context element "includes" no longer
  2510     generate theorems with internal delta predicates (those ending on
  2511     "_axioms") in the premise.
  2512     Resolve particular premise with <locale>.intro to obtain old form.
  2513   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2514     specification and "includes" elements in goal statement.
  2515   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2516     [intro?] and [elim?] (respectively) by default.
  2517   - Experimental command for instantiation of locales in proof contexts:
  2518         instantiate <label>[<attrs>]: <loc>
  2519     Instantiates locale <loc> and adds all its theorems to the current context
  2520     taking into account their attributes.  Label and attrs are optional
  2521     modifiers, like in theorem declarations.  If present, names of
  2522     instantiated theorems are qualified with <label>, and the attributes
  2523     <attrs> are applied after any attributes these theorems might have already.
  2524       If the locale has assumptions, a chained fact of the form
  2525     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2526     are derived.  The command does not support old-style locales declared
  2527     with "locale (open)".
  2528       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2529 
  2530 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2531   (Isar) contexts.
  2532 
  2533 
  2534 *** HOL ***
  2535 
  2536 * Proof import: new image HOL4 contains the imported library from
  2537   the HOL4 system with about 2500 theorems. It is imported by
  2538   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2539   can be used like any other Isabelle image.  See
  2540   HOL/Import/HOL/README for more information.
  2541 
  2542 * Simplifier:
  2543   - Much improved handling of linear and partial orders.
  2544     Reasoners for linear and partial orders are set up for type classes
  2545     "linorder" and "order" respectively, and are added to the default simpset
  2546     as solvers.  This means that the simplifier can build transitivity chains
  2547     to solve goals from the assumptions.
  2548   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2549     of blast or auto after simplification become unnecessary because the goal
  2550     is solved by simplification already.
  2551 
  2552 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2553     all proved in axiomatic type classes for semirings, rings and fields.
  2554 
  2555 * Numerics:
  2556   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2557     now formalized using the Ring_and_Field theory mentioned above.
  2558   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2559     than before, because now they are set up once in a generic manner.
  2560   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2561     Look for the general versions in Ring_and_Field (and Power if they concern
  2562     exponentiation).
  2563 
  2564 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2565 
  2566 * Records:
  2567   - Record types are now by default printed with their type abbreviation
  2568     instead of the list of all field types. This can be configured via
  2569     the reference "print_record_type_abbr".
  2570   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2571     (not enabled by default).
  2572   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2573     EX x. x = sel r to True (not enabled by default).
  2574   - Tactic "record_split_simp_tac" to split and simplify records added.
  2575 
  2576 * 'specification' command added, allowing for definition by
  2577   specification.  There is also an 'ax_specification' command that
  2578   introduces the new constants axiomatically.
  2579 
  2580 * arith(_tac) is now able to generate counterexamples for reals as well.
  2581 
  2582 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2583 
  2584 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2585   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2586 
  2587 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2588   matrix theory to linear programming.
  2589 
  2590 * Unions and Intersections:
  2591   The latex output syntax of UN and INT has been changed
  2592   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2593   i.e. the index formulae has become a subscript.
  2594   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2595 
  2596 * Unions and Intersections over Intervals:
  2597   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2598   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2599   like in normal math, and corresponding versions for < and for intersection.
  2600 
  2601 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2602   lexicographic dictonary ordering has been added as "lexord".
  2603 
  2604 * ML: the legacy theory structures Int and List have been removed. They had
  2605   conflicted with ML Basis Library structures having the same names.
  2606 
  2607 * 'refute' command added to search for (finite) countermodels.  Only works
  2608   for a fragment of HOL.  The installation of an external SAT solver is
  2609   highly recommended.  See "HOL/Refute.thy" for details.
  2610 
  2611 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2612   formulae under an assignment of free variables to random values.
  2613   In contrast to 'refute', it can deal with inductive datatypes,
  2614   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2615   for examples.
  2616 
  2617 
  2618 *** HOLCF ***
  2619 
  2620 * Streams now come with concatenation and are part of the HOLCF image
  2621 
  2622 
  2623 
  2624 New in Isabelle2003 (May 2003)
  2625 ------------------------------
  2626 
  2627 *** General ***
  2628 
  2629 * Provers/simplifier:
  2630 
  2631   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2632     Assumptions are now subject to complete mutual simplification,
  2633     not just from left to right. The simplifier now preserves
  2634     the order of assumptions.
  2635 
  2636     Potential INCOMPATIBILITY:
  2637 
  2638     -- simp sometimes diverges where the old version did
  2639        not, e.g. invoking simp on the goal
  2640 
  2641         [| P (f x); y = x; f x = f y |] ==> Q
  2642 
  2643        now gives rise to the infinite reduction sequence
  2644 
  2645         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2646 
  2647        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2648        kind of problem.
  2649 
  2650     -- Tactics combining classical reasoner and simplification (such as auto)
  2651        are also affected by this change, because many of them rely on
  2652        simp. They may sometimes diverge as well or yield a different numbers
  2653        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2654        in case of problems. Sometimes subsequent calls to the classical
  2655        reasoner will fail because a preceeding call to the simplifier too
  2656        eagerly simplified the goal, e.g. deleted redundant premises.
  2657 
  2658   - The simplifier trace now shows the names of the applied rewrite rules
  2659 
  2660   - You can limit the number of recursive invocations of the simplifier
  2661     during conditional rewriting (where the simplifie tries to solve the
  2662     conditions before applying the rewrite rule):
  2663     ML "simp_depth_limit := n"
  2664     where n is an integer. Thus you can force termination where previously
  2665     the simplifier would diverge.
  2666 
  2667   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2668 
  2669   - No longer aborts on failed congruence proof.  Instead, the
  2670     congruence is ignored.
  2671 
  2672 * Pure: New generic framework for extracting programs from constructive
  2673   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2674   as HOL/Extraction for some case studies.
  2675 
  2676 * Pure: The main goal of the proof state is no longer shown by default, only
  2677 the subgoals. This behaviour is controlled by a new flag.
  2678    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2679 (ML: Proof.show_main_goal).
  2680 
  2681 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2682 rules whose conclusion matches subgoal 1:
  2683       PG menu: Isabelle/Isar -> Show me -> matching rules
  2684 The rules are ordered by how closely they match the subgoal.
  2685 In particular, rules that solve a subgoal outright are displayed first
  2686 (or rather last, the way they are printed).
  2687 (ML: ProofGeneral.print_intros())
  2688 
  2689 * Pure: New flag trace_unify_fail causes unification to print
  2690 diagnostic information (PG: in trace buffer) when it fails. This is
  2691 useful for figuring out why single step proofs like rule, erule or
  2692 assumption failed.
  2693 
  2694 * Pure: Locale specifications now produce predicate definitions
  2695 according to the body of text (covering assumptions modulo local
  2696 definitions); predicate "loc_axioms" covers newly introduced text,
  2697 while "loc" is cumulative wrt. all included locale expressions; the
  2698 latter view is presented only on export into the global theory
  2699 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2700 on the old view without predicates;
  2701 
  2702 * Pure: predefined locales "var" and "struct" are useful for sharing
  2703 parameters (as in CASL, for example); just specify something like
  2704 ``var x + var y + struct M'' as import;
  2705 
  2706 * Pure: improved thms_containing: proper indexing of facts instead of
  2707 raw theorems; check validity of results wrt. current name space;
  2708 include local facts of proof configuration (also covers active
  2709 locales), cover fixed variables in index; may use "_" in term
  2710 specification; an optional limit for the number of printed facts may
  2711 be given (the default is 40);
  2712 
  2713 * Pure: disallow duplicate fact bindings within new-style theory files
  2714 (batch-mode only);
  2715 
  2716 * Provers: improved induct method: assumptions introduced by case
  2717 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2718 the goal statement); "foo" still refers to all facts collectively;
  2719 
  2720 * Provers: the function blast.overloaded has been removed: all constants
  2721 are regarded as potentially overloaded, which improves robustness in exchange
  2722 for slight decrease in efficiency;
  2723 
  2724 * Provers/linorder: New generic prover for transitivity reasoning over
  2725 linear orders.  Note: this prover is not efficient!
  2726 
  2727 * Isar: preview of problems to finish 'show' now produce an error
  2728 rather than just a warning (in interactive mode);
  2729 
  2730 
  2731 *** HOL ***
  2732 
  2733 * arith(_tac)
  2734 
  2735  - Produces a counter example if it cannot prove a goal.
  2736    Note that the counter example may be spurious if the goal is not a formula
  2737    of quantifier-free linear arithmetic.
  2738    In ProofGeneral the counter example appears in the trace buffer.
  2739 
  2740  - Knows about div k and mod k where k is a numeral of type nat or int.
  2741 
  2742  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2743    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2744    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2745 
  2746 * simp's arithmetic capabilities have been enhanced a bit: it now
  2747 takes ~= in premises into account (by performing a case split);
  2748 
  2749 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2750 are distributed over a sum of terms;
  2751 
  2752 * New tactic "trans_tac" and method "trans" instantiate
  2753 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2754 "<=", "<" and "=").
  2755 
  2756 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2757 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2758 
  2759 * 'typedef' command has new option "open" to suppress the set
  2760 definition;
  2761 
  2762 * functions Min and Max on finite sets have been introduced (theory
  2763 Finite_Set);
  2764 
  2765 * attribute [symmetric] now works for relations as well; it turns
  2766 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2767 
  2768 * induct over a !!-quantified statement (say !!x1..xn):
  2769   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2770 
  2771 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2772 %x. None. Warning: empty_def now refers to the previously hidden definition
  2773 of the empty set.
  2774 
  2775 * Algebra: formalization of classical algebra.  Intended as base for
  2776 any algebraic development in Isabelle.  Currently covers group theory
  2777 (up to Sylow's theorem) and ring theory (Universal Property of
  2778 Univariate Polynomials).  Contributions welcome;
  2779 
  2780 * GroupTheory: deleted, since its material has been moved to Algebra;
  2781 
  2782 * Complex: new directory of the complex numbers with numeric constants,
  2783 nonstandard complex numbers, and some complex analysis, standard and
  2784 nonstandard (Jacques Fleuriot);
  2785 
  2786 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2787 
  2788 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2789 Fleuriot);
  2790 
  2791 * Real/HahnBanach: updated and adapted to locales;
  2792 
  2793 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2794 Gray and Kramer);
  2795 
  2796 * UNITY: added the Meier-Sanders theory of progress sets;
  2797 
  2798 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2799 as abstract algorithms, instantiated to the JVM;
  2800 
  2801 * Bali: Java source language formalization. Type system, operational
  2802 semantics, axiomatic semantics. Supported language features:
  2803 classes, interfaces, objects,virtual methods, static methods,
  2804 static/instance fields, arrays, access modifiers, definite
  2805 assignment, exceptions.
  2806 
  2807 
  2808 *** ZF ***
  2809 
  2810 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2811 universe, etc.);
  2812 
  2813 * Main ZF: virtually all theories converted to new-style format;
  2814 
  2815 
  2816 *** ML ***
  2817 
  2818 * Pure: Tactic.prove provides sane interface for internal proofs;
  2819 omits the infamous "standard" operation, so this is more appropriate
  2820 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2821 
  2822 * Pure: improved error reporting of simprocs;
  2823 
  2824 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2825 up simprocs;
  2826 
  2827 
  2828 *** Document preparation ***
  2829 
  2830 * uses \par instead of \\ for line breaks in theory text. This may
  2831 shift some page breaks in large documents. To get the old behaviour
  2832 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2833 
  2834 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2835 other packages
  2836 
  2837 * \<euro> now needs package babel/greek instead of marvosym (which
  2838 broke \Rightarrow)
  2839 
  2840 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2841 textcomp package)
  2842 
  2843 
  2844 
  2845 New in Isabelle2002 (March 2002)
  2846 --------------------------------
  2847 
  2848 *** Document preparation ***
  2849 
  2850 * greatly simplified document preparation setup, including more
  2851 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2852 instructive isatool mkdir; users should basically be able to get
  2853 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2854 users may run a separate document processing stage manually like this:
  2855 "isatool usedir -D output HOL Test && isatool document Test/output";
  2856 
  2857 * theory dependency graph may now be incorporated into documents;
  2858 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2859 with \includegraphics of LaTeX;
  2860 
  2861 * proper spacing of consecutive markup elements, especially text
  2862 blocks after section headings;
  2863 
  2864 * support bold style (for single symbols only), input syntax is like
  2865 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2866 
  2867 * \<bullet> is now output as bold \cdot by default, which looks much
  2868 better in printed text;
  2869 
  2870 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2871 note that these symbols are currently unavailable in Proof General /
  2872 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2873 
  2874 * isatool latex no longer depends on changed TEXINPUTS, instead
  2875 isatool document copies the Isabelle style files to the target
  2876 location;
  2877 
  2878 
  2879 *** Isar ***
  2880 
  2881 * Pure/Provers: improved proof by cases and induction;
  2882   - 'case' command admits impromptu naming of parameters (such as
  2883     "case (Suc n)");
  2884   - 'induct' method divinates rule instantiation from the inductive
  2885     claim; no longer requires excessive ?P bindings for proper
  2886     instantiation of cases;
  2887   - 'induct' method properly enumerates all possibilities of set/type
  2888     rules; as a consequence facts may be also passed through *type*
  2889     rules without further ado;
  2890   - 'induct' method now derives symbolic cases from the *rulified*
  2891     rule (before it used to rulify cases stemming from the internal
  2892     atomized version); this means that the context of a non-atomic
  2893     statement becomes is included in the hypothesis, avoiding the
  2894     slightly cumbersome show "PROP ?case" form;
  2895   - 'induct' may now use elim-style induction rules without chaining
  2896     facts, using ``missing'' premises from the goal state; this allows
  2897     rules stemming from inductive sets to be applied in unstructured
  2898     scripts, while still benefitting from proper handling of non-atomic
  2899     statements; NB: major inductive premises need to be put first, all
  2900     the rest of the goal is passed through the induction;
  2901   - 'induct' proper support for mutual induction involving non-atomic
  2902     rule statements (uses the new concept of simultaneous goals, see
  2903     below);
  2904   - append all possible rule selections, but only use the first
  2905     success (no backtracking);
  2906   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2907   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2908   - added 'print_induct_rules' (covered by help item in recent Proof
  2909     General versions);
  2910   - moved induct/cases attributes to Pure, methods to Provers;
  2911   - generic method setup instantiated for FOL and HOL;
  2912 
  2913 * Pure: support multiple simultaneous goal statements, for example
  2914 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2915 meta-level mechanism, this acts as if several individual goals had
  2916 been stated separately; in particular common proof methods need to be
  2917 repeated in order to cover all claims; note that a single elimination
  2918 step is *not* sufficient to establish the two conjunctions, so this
  2919 fails:
  2920 
  2921   assume "A & B" then have A and B ..   (*".." fails*)
  2922 
  2923 better use "obtain" in situations as above; alternative refer to
  2924 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2925 
  2926 * Pure: proper integration with ``locales''; unlike the original
  2927 version by Florian Kammller, Isar locales package high-level proof
  2928 contexts rather than raw logical ones (e.g. we admit to include
  2929 attributes everywhere); operations on locales include merge and
  2930 rename; support for implicit arguments (``structures''); simultaneous
  2931 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2932 some examples;
  2933 
  2934 * Pure: the following commands have been ``localized'', supporting a
  2935 target locale specification "(in name)": 'lemma', 'theorem',
  2936 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2937 stored both within the locale and at the theory level (exported and
  2938 qualified by the locale name);
  2939 
  2940 * Pure: theory goals may now be specified in ``long'' form, with
  2941 ad-hoc contexts consisting of arbitrary locale elements. for example
  2942 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2943 definitions may be given, too); the result is a meta-level rule with
  2944 the context elements being discharged in the obvious way;
  2945 
  2946 * Pure: new proof command 'using' allows to augment currently used
  2947 facts after a goal statement ('using' is syntactically analogous to
  2948 'apply', but acts on the goal's facts only); this allows chained facts
  2949 to be separated into parts given before and after a claim, as in
  2950 ``from a and b have C using d and e <proof>'';
  2951 
  2952 * Pure: renamed "antecedent" case to "rule_context";
  2953 
  2954 * Pure: new 'judgment' command records explicit information about the
  2955 object-logic embedding (used by several tools internally); no longer
  2956 use hard-wired "Trueprop";
  2957 
  2958 * Pure: added 'corollary' command;
  2959 
  2960 * Pure: fixed 'token_translation' command;
  2961 
  2962 * Pure: removed obsolete 'exported' attribute;
  2963 
  2964 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2965 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2966 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2967 
  2968 * Pure: method 'atomize' presents local goal premises as object-level
  2969 statements (atomic meta-level propositions); setup controlled via
  2970 rewrite rules declarations of 'atomize' attribute; example
  2971 application: 'induct' method with proper rule statements in improper
  2972 proof *scripts*;
  2973 
  2974 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2975 now consider the syntactic context of assumptions, giving a better
  2976 chance to get type-inference of the arguments right (this is
  2977 especially important for locales);
  2978 
  2979 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2980 mode;
  2981 
  2982 * Pure/obtain: the formal conclusion "thesis", being marked as
  2983 ``internal'', may no longer be reference directly in the text;
  2984 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2985 situations;
  2986 
  2987 * Pure: generic 'sym' attribute which declares a rule both as pure
  2988 'elim?' and for the 'symmetric' operation;
  2989 
  2990 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2991 text; the fixed correlation with particular command syntax has been
  2992 discontinued;
  2993 
  2994 * Pure: new method 'rules' is particularly well-suited for proof
  2995 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2996 but often produces more compact proof terms with less detours;
  2997 
  2998 * Pure/Provers/classical: simplified integration with pure rule
  2999 attributes and methods; the classical "intro?/elim?/dest?"
  3000 declarations coincide with the pure ones; the "rule" method no longer
  3001 includes classically swapped intros; "intro" and "elim" methods no
  3002 longer pick rules from the context; also got rid of ML declarations
  3003 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3004 INCOMPATIBILITY;
  3005 
  3006 * Provers/classical: attribute 'swapped' produces classical inversions
  3007 of introduction rules;
  3008 
  3009 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3010 rules instead of full simplifier context; 'iff' attribute handles
  3011 conditional rules;
  3012 
  3013 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3014 
  3015 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3016 "(permissive)" option to recover old behavior;
  3017 
  3018 * HOL: 'inductive' no longer features separate (collective) attributes
  3019 for 'intros' (was found too confusing);
  3020 
  3021 * HOL: properly declared induction rules less_induct and
  3022 wf_induct_rule;
  3023 
  3024 
  3025 *** HOL ***
  3026 
  3027 * HOL: moved over to sane numeral syntax; the new policy is as
  3028 follows:
  3029 
  3030   - 0 and 1 are polymorphic constants, which are defined on any
  3031   numeric type (nat, int, real etc.);
  3032 
  3033   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3034   binary representation internally;
  3035 
  3036   - type nat has special constructor Suc, and generally prefers Suc 0
  3037   over 1::nat and Suc (Suc 0) over 2::nat;
  3038 
  3039 This change may cause significant problems of INCOMPATIBILITY; here
  3040 are some hints on converting existing sources:
  3041 
  3042   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3043   entities, so expressions involving "-" (unary or binary minus) need
  3044   to be spaced properly;
  3045 
  3046   - existing occurrences of "1" may need to be constraint "1::nat" or
  3047   even replaced by Suc 0; similar for old "2";
  3048 
  3049   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3050 
  3051   - remove all special provisions on numerals in proofs;
  3052 
  3053 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3054 representation (depends on bin_arith_simps in the default context);
  3055 
  3056 * HOL: symbolic syntax for x^2 (numeral 2);
  3057 
  3058 * HOL: the class of all HOL types is now called "type" rather than
  3059 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3060 in axclass/classes, instance/arities, and (usually rare) occurrences
  3061 in typings (of consts etc.); internally the class is called
  3062 "HOL.type", ML programs should refer to HOLogic.typeS;
  3063 
  3064 * HOL/record package improvements:
  3065   - new derived operations "fields" to build a partial record section,
  3066     "extend" to promote a fixed record to a record scheme, and
  3067     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3068     declared as simp by default;
  3069   - shared operations ("more", "fields", etc.) now need to be always
  3070     qualified) --- potential INCOMPATIBILITY;
  3071   - removed "make_scheme" operations (use "make" with "extend") --
  3072     INCOMPATIBILITY;
  3073   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3074   - provides cases/induct rules for use with corresponding Isar
  3075     methods (for concrete records, record schemes, concrete more
  3076     parts, and schematic more parts -- in that order);
  3077   - internal definitions directly based on a light-weight abstract
  3078     theory of product types over typedef rather than datatype;
  3079 
  3080 * HOL: generic code generator for generating executable ML code from
  3081 specifications; specific support for HOL constructs such as inductive
  3082 datatypes and sets, as well as recursive functions; can be invoked
  3083 via 'generate_code' theory section;
  3084 
  3085 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3086 
  3087 * HOL: consolidated and renamed several theories.  In particular:
  3088         Ord.thy has been absorbed into HOL.thy
  3089         String.thy has been absorbed into List.thy
  3090 
  3091 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3092 (beware of argument permutation!);
  3093 
  3094 * HOL: linorder_less_split superseded by linorder_cases;
  3095 
  3096 * HOL/List: "nodups" renamed to "distinct";
  3097 
  3098 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3099 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3100   - Ex_def has changed, now need to use some_eq_ex
  3101 
  3102 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3103 in this (rare) case use:
  3104 
  3105   delSWrapper "split_all_tac"
  3106   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3107 
  3108 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3109 MAY FAIL;
  3110 
  3111 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3112 Isabelle's type classes, ^ on functions and relations has too general
  3113 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3114 necessary to attach explicit type constraints;
  3115 
  3116 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3117 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3118 renamed accordingly (eg "compI" -> "rel_compI").
  3119 
  3120 * HOL: syntax translations now work properly with numerals and records
  3121 expressions;
  3122 
  3123 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3124 of "lam" -- INCOMPATIBILITY;
  3125 
  3126 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3127 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3128 renamed "Product_Type.unit";
  3129 
  3130 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3131 
  3132 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3133 the "cases" method);
  3134 
  3135 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3136 Florian Kammller);
  3137 
  3138 * HOL/IMP: updated and converted to new-style theory format; several
  3139 parts turned into readable document, with proper Isar proof texts and
  3140 some explanations (by Gerwin Klein);
  3141 
  3142 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3143 
  3144 * HOL-Hyperreal is now a logic image;
  3145 
  3146 
  3147 *** HOLCF ***
  3148 
  3149 * Isar: consts/constdefs supports mixfix syntax for continuous
  3150 operations;
  3151 
  3152 * Isar: domain package adapted to new-style theory format, e.g. see
  3153 HOLCF/ex/Dnat.thy;
  3154 
  3155 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3156 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3157 lift.induct_tac, always use UU instead of Undef;
  3158 
  3159 * HOLCF/IMP: updated and converted to new-style theory;
  3160 
  3161 
  3162 *** ZF ***
  3163 
  3164 * Isar: proper integration of logic-specific tools and packages,
  3165 including theory commands '(co)inductive', '(co)datatype',
  3166 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3167 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3168 
  3169 * theory Main no longer includes AC; for the Axiom of Choice, base
  3170 your theory on Main_ZFC;
  3171 
  3172 * the integer library now covers quotients and remainders, with many
  3173 laws relating division to addition, multiplication, etc.;
  3174 
  3175 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3176 typeless version of the formalism;
  3177 
  3178 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3179 format;
  3180 
  3181 * ZF/Induct: new directory for examples of inductive definitions,
  3182 including theory Multiset for multiset orderings; converted to
  3183 new-style theory format;
  3184 
  3185 * ZF: many new theorems about lists, ordinals, etc.;
  3186 
  3187 
  3188 *** General ***
  3189 
  3190 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3191 variable proof controls level of detail: 0 = no proofs (only oracle
  3192 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3193 also ref manual for further ML interfaces;
  3194 
  3195 * Pure/axclass: removed obsolete ML interface
  3196 goal_subclass/goal_arity;
  3197 
  3198 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3199 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3200 separate tokens, so expressions involving minus need to be spaced
  3201 properly;
  3202 
  3203 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3204 rather than "infixl" or "infixr";
  3205 
  3206 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3207 sort constraint specifications in type inference; e.g. "x::_::foo"
  3208 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3209 type variable);
  3210 
  3211 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3212 control output of nested => (types); the default behavior is
  3213 "type_brackets";
  3214 
  3215 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3216 tokens into AST constants;
  3217 
  3218 * Pure/syntax: prefer later declarations of translations and print
  3219 translation functions; potential INCOMPATIBILITY: need to reverse
  3220 multiple declarations for same syntax element constant;
  3221 
  3222 * Pure/show_hyps reset by default (in accordance to existing Isar
  3223 practice);
  3224 
  3225 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3226 addSafter;
  3227 
  3228 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3229 as well;
  3230 
  3231 * system: tested support for MacOS X; should be able to get Isabelle +
  3232 Proof General to work in a plain Terminal after installing Poly/ML
  3233 (e.g. from the Isabelle distribution area) and GNU bash alone
  3234 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3235 support requires further installations, e.g. from
  3236 http://fink.sourceforge.net/);
  3237 
  3238 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3239 
  3240 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3241 of 40 MB), cf. ML_OPTIONS;
  3242 
  3243 * system: Proof General keywords specification is now part of the
  3244 Isabelle distribution (see etc/isar-keywords.el);
  3245 
  3246 * system: support for persistent Proof General sessions (refrain from
  3247 outdating all loaded theories on startup); user may create writable
  3248 logic images like this: ``isabelle -q HOL Test'';
  3249 
  3250 * system: smart selection of Isabelle process versus Isabelle
  3251 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3252 run both "isabelle" and "Isabelle" even if file names are badly
  3253 damaged (executable inspects the case of the first letter of its own
  3254 name); added separate "isabelle-process" and "isabelle-interface";
  3255 
  3256 * system: refrain from any attempt at filtering input streams; no
  3257 longer support ``8bit'' encoding of old isabelle font, instead proper
  3258 iso-latin characters may now be used; the related isatools
  3259 "symbolinput" and "nonascii" have disappeared as well;
  3260 
  3261 * system: removed old "xterm" interface (the print modes "xterm" and
  3262 "xterm_color" are still available for direct use in a suitable
  3263 terminal);
  3264 
  3265 
  3266 
  3267 New in Isabelle99-2 (February 2001)
  3268 -----------------------------------
  3269 
  3270 *** Overview of INCOMPATIBILITIES ***
  3271 
  3272 * HOL: please note that theories in the Library and elsewhere often use the
  3273 new-style (Isar) format; to refer to their theorems in an ML script you must
  3274 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3275 
  3276 * HOL: inductive package no longer splits induction rule aggressively,
  3277 but only as far as specified by the introductions given; the old
  3278 format may be recovered via ML function complete_split_rule or attribute
  3279 'split_rule (complete)';
  3280 
  3281 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3282 gfp_Tarski to gfp_unfold;
  3283 
  3284 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3285 
  3286 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3287 relation); infix "^^" has been renamed "``"; infix "``" has been
  3288 renamed "`"; "univalent" has been renamed "single_valued";
  3289 
  3290 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3291 operation;
  3292 
  3293 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3294 
  3295 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3296 
  3297 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3298 consequence, it is no longer monotonic wrt. the local goal context
  3299 (which is now passed through the inductive cases);
  3300 
  3301 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3302 \<gg> to \<ggreater>;
  3303 
  3304 
  3305 *** Document preparation ***
  3306 
  3307 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3308 available: are "it" for near math-mode best-style output, "sl" for
  3309 slanted text style, and "tt" for plain type-writer; if no
  3310 \isabellestyle command is given, output is according to slanted
  3311 type-writer);
  3312 
  3313 * support sub/super scripts (for single symbols only), input syntax is
  3314 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3315 
  3316 * some more standard symbols; see Appendix A of the system manual for
  3317 the complete list of symbols defined in isabellesym.sty;
  3318 
  3319 * improved isabelle style files; more abstract symbol implementation
  3320 (should now use \isamath{...} and \isatext{...} in custom symbol
  3321 definitions);
  3322 
  3323 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3324 state; Note that presentation of goal states does not conform to
  3325 actual human-readable proof documents.  Please do not include goal
  3326 states into document output unless you really know what you are doing!
  3327 
  3328 * proper indentation of antiquoted output with proportional LaTeX
  3329 fonts;
  3330 
  3331 * no_document ML operator temporarily disables LaTeX document
  3332 generation;
  3333 
  3334 * isatool unsymbolize tunes sources for plain ASCII communication;
  3335 
  3336 
  3337 *** Isar ***
  3338 
  3339 * Pure: Isar now suffers initial goal statements to contain unbound
  3340 schematic variables (this does not conform to actual readable proof
  3341 documents, due to unpredictable outcome and non-compositional proof
  3342 checking); users who know what they are doing may use schematic goals
  3343 for Prolog-style synthesis of proven results;
  3344 
  3345 * Pure: assumption method (an implicit finishing) now handles actual
  3346 rules as well;
  3347 
  3348 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3349 initial goal, declare "that" only as Pure intro (only for single
  3350 steps); the "that" rule assumption may now be involved in implicit
  3351 finishing, thus ".." becomes a feasible for trivial obtains;
  3352 
  3353 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3354 instance proofs may be performed by "..";
  3355 
  3356 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3357 statements as well;
  3358 
  3359 * Pure: more robust selection of calculational rules;
  3360 
  3361 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3362 rule (as well as the assumption rule);
  3363 
  3364 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3365 lemmas, using the graph browser tool;
  3366 
  3367 * Pure: predict failure of "show" in interactive mode;
  3368 
  3369 * Pure: 'thms_containing' now takes actual terms as arguments;
  3370 
  3371 * HOL: improved method 'induct' --- now handles non-atomic goals
  3372 (potential INCOMPATIBILITY); tuned error handling;
  3373 
  3374 * HOL: cases and induct rules now provide explicit hints about the
  3375 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3376 any remaining facts are inserted into the goal verbatim;
  3377 
  3378 * HOL: local contexts (aka cases) may now contain term bindings as
  3379 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3380 the result to be shown in each case;
  3381 
  3382 * HOL: added 'recdef_tc' command;
  3383 
  3384 * isatool convert assists in eliminating legacy ML scripts;
  3385 
  3386 
  3387 *** HOL ***
  3388 
  3389 * HOL/Library: a collection of generic theories to be used together
  3390 with main HOL; the theory loader path already includes this directory
  3391 by default; the following existing theories have been moved here:
  3392 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3393 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3394 
  3395 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3396 modelling and verification task performed in Isabelle/HOL +
  3397 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3398 
  3399 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3400 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3401 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3402 'domain', this makes the theory consistent with mathematical
  3403 literature;
  3404 
  3405 * HOL basics: added overloaded operations "inverse" and "divide"
  3406 (infix "/"), syntax for generic "abs" operation, generic summation
  3407 operator \<Sum>;
  3408 
  3409 * HOL/typedef: simplified package, provide more useful rules (see also
  3410 HOL/subset.thy);
  3411 
  3412 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3413 now expressed as a proper nested rule (old-style tactic scripts may
  3414 require atomize_strip_tac to cope with non-atomic premises);
  3415 
  3416 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3417 to "split_conv" (old name still available for compatibility);
  3418 
  3419 * HOL: improved concrete syntax for strings (e.g. allows translation
  3420 rules with string literals);
  3421 
  3422 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3423  and Fleuriot's mechanization of analysis, including the transcendental
  3424  functions for the reals;
  3425 
  3426 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3427 
  3428 
  3429 *** CTT ***
  3430 
  3431 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3432 "lam" is displayed as TWO lambda-symbols
  3433 
  3434 * CTT: theory Main now available, containing everything (that is, Bool
  3435 and Arith);
  3436 
  3437 
  3438 *** General ***
  3439 
  3440 * Pure: the Simplifier has been implemented properly as a derived rule
  3441 outside of the actual kernel (at last!); the overall performance
  3442 penalty in practical applications is about 50%, while reliability of
  3443 the Isabelle inference kernel has been greatly improved;
  3444 
  3445 * print modes "brackets" and "no_brackets" control output of nested =>
  3446 (types) and ==> (props); the default behaviour is "brackets";
  3447 
  3448 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3449 as assumptions as well;
  3450 
  3451 * system: support Poly/ML 4.0;
  3452 
  3453 * system: isatool install handles KDE version 1 or 2;
  3454 
  3455 
  3456 
  3457 New in Isabelle99-1 (October 2000)
  3458 ----------------------------------
  3459 
  3460 *** Overview of INCOMPATIBILITIES ***
  3461 
  3462 * HOL: simplification of natural numbers is much changed; to partly
  3463 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3464 issue the following ML commands:
  3465 
  3466   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3467   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3468 
  3469 * HOL: simplification no longer dives into case-expressions; this is
  3470 controlled by "t.weak_case_cong" for each datatype t;
  3471 
  3472 * HOL: nat_less_induct renamed to less_induct;
  3473 
  3474 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3475 fixsome to patch .thy and .ML sources automatically;
  3476 
  3477   select_equality  -> some_equality
  3478   select_eq_Ex     -> some_eq_ex
  3479   selectI2EX       -> someI2_ex
  3480   selectI2         -> someI2
  3481   selectI          -> someI
  3482   select1_equality -> some1_equality
  3483   Eps_sym_eq       -> some_sym_eq_trivial
  3484   Eps_eq           -> some_eq_trivial
  3485 
  3486 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3487 
  3488 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3489 instead);
  3490 
  3491 * HOL: the recursion equations generated by 'recdef' are now called
  3492 f.simps instead of f.rules;
  3493 
  3494 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3495 
  3496 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3497 sometimes be needed;
  3498 
  3499 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3500 
  3501 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3502 
  3503 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3504 product is now "<*>" instead of "Times"; the lexicographic product is
  3505 now "<*lex*>" instead of "**";
  3506 
  3507 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3508 of main HOL, but was unused); better use HOL's datatype package;
  3509 
  3510 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3511 the old syntax may be recovered as follows:
  3512 
  3513   syntax (symbols)
  3514     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3515       (infixl "\\<oplus>" 100)
  3516 
  3517 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3518 
  3519 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3520 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3521 internally;
  3522 
  3523 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3524 changed from A/r to A//r;
  3525 
  3526 * ZF: new treatment of arithmetic (nat & int) may break some old
  3527 proofs;
  3528 
  3529 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3530 rulify -> rule_format, elimify -> elim_format, ...);
  3531 
  3532 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3533 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3534 should have to change intro!! to intro? only); replaced "delrule" by
  3535 "rule del";
  3536 
  3537 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3538 
  3539 * Provers: strengthened force_tac by using new first_best_tac;
  3540 
  3541 * LaTeX document preparation: several changes of isabelle.sty (see
  3542 lib/texinputs);
  3543 
  3544 
  3545 *** Document preparation ***
  3546 
  3547 * formal comments (text blocks etc.) in new-style theories may now
  3548 contain antiquotations of thm/prop/term/typ/text to be presented
  3549 according to latex print mode; concrete syntax is like this:
  3550 @{term[show_types] "f(x) = a + x"};
  3551 
  3552 * isatool mkdir provides easy setup of Isabelle session directories,
  3553 including proper document sources;
  3554 
  3555 * generated LaTeX sources are now deleted after successful run
  3556 (isatool document -c); may retain a copy somewhere else via -D option
  3557 of isatool usedir;
  3558 
  3559 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3560 style files, achieving self-contained LaTeX sources and simplifying
  3561 LaTeX debugging;
  3562 
  3563 * old-style theories now produce (crude) LaTeX output as well;
  3564 
  3565 * browser info session directories are now self-contained (may be put
  3566 on WWW server seperately); improved graphs of nested sessions; removed
  3567 graph for 'all sessions';
  3568 
  3569 * several improvements in isabelle style files; \isabellestyle{it}
  3570 produces fake math mode output; \isamarkupheader is now \section by
  3571 default; see lib/texinputs/isabelle.sty etc.;
  3572 
  3573 
  3574 *** Isar ***
  3575 
  3576 * Isar/Pure: local results and corresponding term bindings are now
  3577 subject to Hindley-Milner polymorphism (similar to ML); this
  3578 accommodates incremental type-inference very nicely;
  3579 
  3580 * Isar/Pure: new derived language element 'obtain' supports
  3581 generalized existence reasoning;
  3582 
  3583 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3584 support accumulation of results, without applying any rules yet;
  3585 useful to collect intermediate results without explicit name
  3586 references, and for use with transitivity rules with more than 2
  3587 premises;
  3588 
  3589 * Isar/Pure: scalable support for case-analysis type proofs: new
  3590 'case' language element refers to local contexts symbolically, as
  3591 produced by certain proof methods; internally, case names are attached
  3592 to theorems as "tags";
  3593 
  3594 * Isar/Pure: theory command 'hide' removes declarations from
  3595 class/type/const name spaces;
  3596 
  3597 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3598 indicate potential overloading;
  3599 
  3600 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3601 
  3602 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3603 "{a,b,c}" instead of {a,b,c};
  3604 
  3605 * Isar/Pure now provides its own version of intro/elim/dest
  3606 attributes; useful for building new logics, but beware of confusion
  3607 with the version in Provers/classical;
  3608 
  3609 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3610 case name 'antecedent';
  3611 
  3612 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3613 to the current context is now done automatically);
  3614 
  3615 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3616 for definining proof methods in ML;
  3617 
  3618 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3619 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3620 most cases, one should have to change intro!! to intro? only);
  3621 replaced "delrule" by "rule del";
  3622 
  3623 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3624 'symmetric' attribute (the latter supercedes [RS sym]);
  3625 
  3626 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3627 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3628 well (including splits);
  3629 
  3630 * Isar/Provers: Simplifier and Classical methods now support all kind
  3631 of modifiers used in the past, including 'cong', 'iff', etc.
  3632 
  3633 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3634 of Simplifier and Classical reasoner);
  3635 
  3636 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3637 now support named cases; major packages (inductive, datatype, primrec,
  3638 recdef) support case names and properly name parameters;
  3639 
  3640 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3641 monotonicity conditions are extracted to be proven at end of
  3642 calculations;
  3643 
  3644 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3645 method anyway;
  3646 
  3647 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3648 split_if split_if_asm; datatype package provides theorems foo.splits =
  3649 foo.split foo.split_asm for each datatype;
  3650 
  3651 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3652 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3653 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3654 use "(cases (simplified))" method in proper proof texts);
  3655 
  3656 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3657 
  3658 * Isar: names of theorems etc. may be natural numbers as well;
  3659 
  3660 * Isar: 'pr' command: optional arguments for goals_limit and
  3661 ProofContext.prems_limit; no longer prints theory contexts, but only
  3662 proof states;
  3663 
  3664 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3665 additional print modes to be specified; e.g. "pr(latex)" will print
  3666 proof state according to the Isabelle LaTeX style;
  3667 
  3668 * Isar: improved support for emulating tactic scripts, including proof
  3669 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3670 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3671 (for HOL datatypes);
  3672 
  3673 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3674 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3675 'proof method scripts' have to be in depth-first order;
  3676 
  3677 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3678 
  3679 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3680 should instead use individual commands for printing items
  3681 (print_commands, print_methods etc.);
  3682 
  3683 * Isar: added 'nothing' --- the empty list of theorems;
  3684 
  3685 
  3686 *** HOL ***
  3687 
  3688 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3689 corresponding virtual machine and a specification of its bytecode
  3690 verifier and a lightweight bytecode verifier, including proofs of
  3691 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3692 Cornelia Pusch (see also the homepage of project Bali at
  3693 http://isabelle.in.tum.de/Bali/);
  3694 
  3695 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3696 Clemens Ballarin;
  3697 
  3698 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3699 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3700 Rasmussen;
  3701 
  3702 * HOL/Lattice: fundamental concepts of lattice theory and order
  3703 structures, including duals, properties of bounds versus algebraic
  3704 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3705 Theorem for complete lattices etc.; may also serve as a demonstration
  3706 for abstract algebraic reasoning using axiomatic type classes, and
  3707 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3708 
  3709 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3710 von Oheimb;
  3711 
  3712 * HOL/IMPP: extension of IMP with local variables and mutually
  3713 recursive procedures, by David von Oheimb;
  3714 
  3715 * HOL/Lambda: converted into new-style theory and document;
  3716 
  3717 * HOL/ex/Multiquote: example of multiple nested quotations and
  3718 anti-quotations -- basically a generalized version of de-Bruijn
  3719 representation; very useful in avoiding lifting of operations;
  3720 
  3721 * HOL/record: added general record equality rule to simpset; fixed
  3722 select-update simplification procedure to handle extended records as
  3723 well; admit "r" as field name;
  3724 
  3725 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3726 other numeric types and also as the identity of groups, rings, etc.;
  3727 
  3728 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3729 Types nat and int belong to this axclass;
  3730 
  3731 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3732    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3733    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3734   two terms #m*u and #n*u are replaced by #(m+n)*u
  3735     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3736   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3737     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3738 
  3739 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3740 powerful prover for predicate logic but knows nothing of clasets; see
  3741 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3742 
  3743 * HOL: new version of "case_tac" subsumes both boolean case split and
  3744 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3745 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3746 
  3747 * HOL: simplification no longer dives into case-expressions: only the
  3748 selector expression is simplified, but not the remaining arms; to
  3749 enable full simplification of case-expressions for datatype t, you may
  3750 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3751 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3752 
  3753 * HOL/recdef: the recursion equations generated by 'recdef' for
  3754 function 'f' are now called f.simps instead of f.rules; if all
  3755 termination conditions are proved automatically, these simplification
  3756 rules are added to the simpset, as in primrec; rules may be named
  3757 individually as well, resulting in a separate list of theorems for
  3758 each equation;
  3759 
  3760 * HOL/While is a new theory that provides a while-combinator. It
  3761 permits the definition of tail-recursive functions without the
  3762 provision of a termination measure. The latter is necessary once the
  3763 invariant proof rule for while is applied.
  3764 
  3765 * HOL: new (overloaded) notation for the set of elements below/above
  3766 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3767 
  3768 * HOL: theorems impI, allI, ballI bound as "strip";
  3769 
  3770 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3771 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3772 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3773 
  3774 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3775 
  3776 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3777 main HOL, but was unused);
  3778 
  3779 * HOL: fewer consts declared as global (e.g. have to refer to
  3780 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3781 
  3782 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3783 in case of overlap with user translations (e.g. judgements over
  3784 tuples); (note that the underlying logical represenation is still
  3785 bogus);
  3786 
  3787 
  3788 *** ZF ***
  3789 
  3790 * ZF: simplification automatically cancels common terms in arithmetic
  3791 expressions over nat and int;
  3792 
  3793 * ZF: new treatment of nat to minimize type-checking: all operators
  3794 coerce their operands to a natural number using the function natify,
  3795 making the algebraic laws unconditional;
  3796 
  3797 * ZF: as above, for int: operators coerce their operands to an integer
  3798 using the function intify;
  3799 
  3800 * ZF: the integer library now contains many of the usual laws for the
  3801 orderings, including $<=, and monotonicity laws for $+ and $*;
  3802 
  3803 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3804 simplification;
  3805 
  3806 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3807 to the simplifier and classical reasoner simultaneously;
  3808 
  3809 
  3810 *** General ***
  3811 
  3812 * Provers: blast_tac now handles actual object-logic rules as
  3813 assumptions; note that auto_tac uses blast_tac internally as well;
  3814 
  3815 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3816 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3817 
  3818 * Provers: delrules now handles destruct rules as well (no longer need
  3819 explicit make_elim);
  3820 
  3821 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3822   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3823 use instead the strong form,
  3824   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3825 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3826 from destruct-rules;
  3827 
  3828 * Provers: Simplifier.easy_setup provides a fast path to basic
  3829 Simplifier setup for new object-logics;
  3830 
  3831 * Pure: AST translation rules no longer require constant head on LHS;
  3832 
  3833 * Pure: improved name spaces: ambiguous output is qualified; support
  3834 for hiding of names;
  3835 
  3836 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3837 XSYMBOL_HOME; no longer need to do manual configuration in most
  3838 situations;
  3839 
  3840 * system: compression of ML heaps images may now be controlled via -c
  3841 option of isabelle and isatool usedir (currently only observed by
  3842 Poly/ML);
  3843 
  3844 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3845 useful for remote X11);
  3846 
  3847 * system: provide TAGS file for Isabelle sources;
  3848 
  3849 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3850 order;
  3851 
  3852 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3853 timing flag supersedes proof_timing and Toplevel.trace;
  3854 
  3855 * ML: new combinators |>> and |>>> for incremental transformations
  3856 with secondary results (e.g. certain theory extensions):
  3857 
  3858 * ML: PureThy.add_defs gets additional argument to indicate potential
  3859 overloading (usually false);
  3860 
  3861 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3862 results;
  3863 
  3864 
  3865 
  3866 New in Isabelle99 (October 1999)
  3867 --------------------------------
  3868 
  3869 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3870 
  3871 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3872 are no longer simplified.  (This allows the simplifier to unfold recursive
  3873 functional programs.)  To restore the old behaviour, declare
  3874 
  3875     Delcongs [if_weak_cong];
  3876 
  3877 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3878 complement;
  3879 
  3880 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3881 
  3882 * HOL/datatype: mutual_induct_tac no longer exists --
  3883   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3884 
  3885 * HOL/typedef: fixed type inference for representing set; type
  3886 arguments now have to occur explicitly on the rhs as type constraints;
  3887 
  3888 * ZF: The con_defs part of an inductive definition may no longer refer
  3889 to constants declared in the same theory;
  3890 
  3891 * HOL, ZF: the function mk_cases, generated by the inductive
  3892 definition package, has lost an argument.  To simplify its result, it
  3893 uses the default simpset instead of a supplied list of theorems.
  3894 
  3895 * HOL/List: the constructors of type list are now Nil and Cons;
  3896 
  3897 * Simplifier: the type of the infix ML functions
  3898         setSSolver addSSolver setSolver addSolver
  3899 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3900 for packaging solvers. A solver is created via
  3901         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3902 where the string argument is only a comment.
  3903 
  3904 
  3905 *** Proof tools ***
  3906 
  3907 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3908 decision procedure for linear arithmetic. Currently it is used for
  3909 types `nat', `int', and `real' in HOL (see below); it can, should and
  3910 will be instantiated for other types and logics as well.
  3911 
  3912 * The simplifier now accepts rewrite rules with flexible heads, eg
  3913      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3914   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3915   matching.
  3916 
  3917 
  3918 *** General ***
  3919 
  3920 * New Isabelle/Isar subsystem provides an alternative to traditional
  3921 tactical theorem proving; together with the ProofGeneral/isar user
  3922 interface it offers an interactive environment for developing human
  3923 readable proof documents (Isar == Intelligible semi-automated
  3924 reasoning); for further information see isatool doc isar-ref,
  3925 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3926 
  3927 * improved and simplified presentation of theories: better HTML markup
  3928 (including colors), graph views in several sizes; isatool usedir now
  3929 provides a proper interface for user theories (via -P option); actual
  3930 document preparation based on (PDF)LaTeX is available as well (for
  3931 new-style theories only); see isatool doc system for more information;
  3932 
  3933 * native support for Proof General, both for classic Isabelle and
  3934 Isabelle/Isar;
  3935 
  3936 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3937 using the graph browser tool;
  3938 
  3939 * Isabelle manuals now also available as PDF;
  3940 
  3941 * theory loader rewritten from scratch (may not be fully
  3942 bug-compatible); old loadpath variable has been replaced by show_path,
  3943 add_path, del_path, reset_path functions; new operations such as
  3944 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3945 isatool doc ref);
  3946 
  3947 * improved isatool install: option -k creates KDE application icon,
  3948 option -p DIR installs standalone binaries;
  3949 
  3950 * added ML_PLATFORM setting (useful for cross-platform installations);
  3951 more robust handling of platform specific ML images for SML/NJ;
  3952 
  3953 * the settings environment is now statically scoped, i.e. it is never
  3954 created again in sub-processes invoked from isabelle, isatool, or
  3955 Isabelle;
  3956 
  3957 * path element specification '~~' refers to '$ISABELLE_HOME';
  3958 
  3959 * in locales, the "assumes" and "defines" parts may be omitted if
  3960 empty;
  3961 
  3962 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3963 long arrows);
  3964 
  3965 * new print_mode "HTML";
  3966 
  3967 * new flag show_tags controls display of tags of theorems (which are
  3968 basically just comments that may be attached by some tools);
  3969 
  3970 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3971 mode and goal output format:
  3972 
  3973 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3974 244c244
  3975 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3976 ---
  3977 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3978 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3979 181c181
  3980 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3981 ---
  3982 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3983 
  3984 * function bind_thms stores lists of theorems (cf. bind_thm);
  3985 
  3986 * new shorthand tactics ftac, eatac, datac, fatac;
  3987 
  3988 * qed (and friends) now accept "" as result name; in that case the
  3989 theorem is not stored, but proper checks and presentation of the
  3990 result still apply;
  3991 
  3992 * theorem database now also indexes constants "Trueprop", "all",
  3993 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3994 
  3995 
  3996 *** HOL ***
  3997 
  3998 ** HOL arithmetic **
  3999 
  4000 * There are now decision procedures for linear arithmetic over nat and
  4001 int:
  4002 
  4003 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4004 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4005 are treated as atomic; subformulae not involving type `nat' or `int'
  4006 are ignored; quantified subformulae are ignored unless they are
  4007 positive universal or negative existential. The tactic has to be
  4008 invoked by hand and can be a little bit slow. In particular, the
  4009 running time is exponential in the number of occurrences of `min' and
  4010 `max', and `-' on `nat'.
  4011 
  4012 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4013 (negated) (in)equalities among the premises and the conclusion into
  4014 account (i.e. no compound formulae) and does not know about `min' and
  4015 `max', and `-' on `nat'. It is fast and is used automatically by the
  4016 simplifier.
  4017 
  4018 NB: At the moment, these decision procedures do not cope with mixed
  4019 nat/int formulae where the two parts interact, such as `m < n ==>
  4020 int(m) < int(n)'.
  4021 
  4022 * HOL/Numeral provides a generic theory of numerals (encoded
  4023 efficiently as bit strings); setup for types nat/int/real is in place;
  4024 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4025 int, existing theories and proof scripts may require a few additional
  4026 type constraints;
  4027 
  4028 * integer division and remainder can now be performed on constant
  4029 arguments;
  4030 
  4031 * many properties of integer multiplication, division and remainder
  4032 are now available;
  4033 
  4034 * An interface to the Stanford Validity Checker (SVC) is available through the
  4035 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4036 are proved automatically.  SVC must be installed separately, and its results
  4037 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4038 invocation of the underlying oracle).  For SVC see
  4039   http://verify.stanford.edu/SVC
  4040 
  4041 * IsaMakefile: the HOL-Real target now builds an actual image;
  4042 
  4043 
  4044 ** HOL misc **
  4045 
  4046 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4047 (in Isabelle/Isar) -- by Gertrud Bauer;
  4048 
  4049 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4050 analysis for assembly languages with subtypes;
  4051 
  4052 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4053 -- avoids syntactic ambiguities and treats state, transition, and
  4054 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4055 changed syntax and (many) tactics;
  4056 
  4057 * HOL/inductive: Now also handles more general introduction rules such
  4058   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4059   theorems are now maintained within the theory (maintained via the
  4060   "mono" attribute);
  4061 
  4062 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4063   (using function types) such as
  4064 
  4065   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4066 
  4067 * HOL/record: record_simproc (part of the default simpset) takes care
  4068 of selectors applied to updated records; record_split_tac is no longer
  4069 part of the default claset; update_defs may now be removed from the
  4070 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4071 
  4072   claset_ref () := claset() addSWrapper record_split_wrapper;
  4073   Delsimprocs [record_simproc]
  4074 
  4075 * HOL/typedef: fixed type inference for representing set; type
  4076 arguments now have to occur explicitly on the rhs as type constraints;
  4077 
  4078 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4079 names rather than an ML expression;
  4080 
  4081 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4082 supplied later.  Program schemes can be defined, such as
  4083     "While B C s = (if B s then While B C (C s) else s)"
  4084 where the well-founded relation can be chosen after B and C have been given.
  4085 
  4086 * HOL/List: the constructors of type list are now Nil and Cons;
  4087 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4088 course, ML tools referring to List.list.op # etc. have to be adapted;
  4089 
  4090 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4091 disabled by default; run isabelle with option -m HOL to get back to
  4092 the original Gordon/HOL-style output;
  4093 
  4094 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4095 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4096 
  4097 * HOL basic syntax simplified (more orthogonal): all variants of
  4098 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4099 Eps operator is provided as well: "SOME x. P[x]";
  4100 
  4101 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4102 
  4103 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4104 thus available for user theories;
  4105 
  4106 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4107 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4108 time;
  4109 
  4110 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4111 several times and then mp;
  4112 
  4113 
  4114 *** LK ***
  4115 
  4116 * the notation <<...>> is now available as a notation for sequences of
  4117 formulas;
  4118 
  4119 * the simplifier is now installed
  4120 
  4121 * the axiom system has been generalized (thanks to Soren Heilmann)
  4122 
  4123 * the classical reasoner now has a default rule database
  4124 
  4125 
  4126 *** ZF ***
  4127 
  4128 * new primrec section allows primitive recursive functions to be given
  4129 directly (as in HOL) over datatypes and the natural numbers;
  4130 
  4131 * new tactics induct_tac and exhaust_tac for induction (or case
  4132 analysis) over datatypes and the natural numbers;
  4133 
  4134 * the datatype declaration of type T now defines the recursor T_rec;
  4135 
  4136 * simplification automatically does freeness reasoning for datatype
  4137 constructors;
  4138 
  4139 * automatic type-inference, with AddTCs command to insert new
  4140 type-checking rules;
  4141 
  4142 * datatype introduction rules are now added as Safe Introduction rules
  4143 to the claset;
  4144 
  4145 * the syntax "if P then x else y" is now available in addition to
  4146 if(P,x,y);
  4147 
  4148 
  4149 *** Internal programming interfaces ***
  4150 
  4151 * tuned simplifier trace output; new flag debug_simp;
  4152 
  4153 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4154 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4155 
  4156 * AxClass.axclass_tac lost the theory argument;
  4157 
  4158 * tuned current_goals_markers semantics: begin / end goal avoids
  4159 printing empty lines;
  4160 
  4161 * removed prs and prs_fn hook, which was broken because it did not
  4162 include \n in its semantics, forcing writeln to add one
  4163 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4164 string -> unit if you really want to output text without newline;
  4165 
  4166 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4167 plain output, interface builders may have to enable 'isabelle_font'
  4168 mode to get Isabelle font glyphs as before;
  4169 
  4170 * refined token_translation interface; INCOMPATIBILITY: output length
  4171 now of type real instead of int;
  4172 
  4173 * theory loader actions may be traced via new ThyInfo.add_hook
  4174 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4175 your own database of information attached to *whole* theories -- as
  4176 opposed to intra-theory data slots offered via TheoryDataFun;
  4177 
  4178 * proper handling of dangling sort hypotheses (at last!);
  4179 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4180 extra sort hypotheses that can be witnessed from the type signature;
  4181 the force_strip_shyps flag is gone, any remaining shyps are simply
  4182 left in the theorem (with a warning issued by strip_shyps_warning);
  4183 
  4184 
  4185 
  4186 New in Isabelle98-1 (October 1998)
  4187 ----------------------------------
  4188 
  4189 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4190 
  4191 * several changes of automated proof tools;
  4192 
  4193 * HOL: major changes to the inductive and datatype packages, including
  4194 some minor incompatibilities of theory syntax;
  4195 
  4196 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4197 called `inj_on';
  4198 
  4199 * HOL: removed duplicate thms in Arith:
  4200   less_imp_add_less  should be replaced by  trans_less_add1
  4201   le_imp_add_le      should be replaced by  trans_le_add1
  4202 
  4203 * HOL: unary minus is now overloaded (new type constraints may be
  4204 required);
  4205 
  4206 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4207 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4208 now taken as an integer constant.
  4209 
  4210 * Pure: ML function 'theory_of' renamed to 'theory';
  4211 
  4212 
  4213 *** Proof tools ***
  4214 
  4215 * Simplifier:
  4216   1. Asm_full_simp_tac is now more aggressive.
  4217      1. It will sometimes reorient premises if that increases their power to
  4218         simplify.
  4219      2. It does no longer proceed strictly from left to right but may also
  4220         rotate premises to achieve further simplification.
  4221      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4222      old Asm_full_simp_tac in that it does not rotate premises.
  4223   2. The simplifier now knows a little bit about nat-arithmetic.
  4224 
  4225 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4226 allows for selected deletion of wrappers, by introduction of names for
  4227 wrapper functionals.  This implies that addbefore, addSbefore,
  4228 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4229 and that adding two tactics with the same name overwrites the first
  4230 one (emitting a warning).
  4231   type wrapper = (int -> tactic) -> (int -> tactic)
  4232   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4233   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4234   delWrapper, delSWrapper: claset *  string            -> claset
  4235   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4236 
  4237 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4238 semantics; addbefore now affects only the unsafe part of step_tac
  4239 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4240 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4241 by Force_tac;
  4242 
  4243 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4244 compWrapper; added safe wrapper (and access functions for it);
  4245 
  4246 * HOL/split_all_tac is now much faster and fails if there is nothing
  4247 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4248 and the names of the automatically generated variables have changed.
  4249 split_all_tac has moved within claset() from unsafe wrappers to safe
  4250 wrappers, which means that !!-bound variables are split much more
  4251 aggressively, and safe_tac and clarify_tac now split such variables.
  4252 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4253 Note: the same holds for record_split_tac, which does the job of
  4254 split_all_tac for record fields.
  4255 
  4256 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4257 permanently to the default simpset using Addsplits just like
  4258 Addsimps. They can be removed via Delsplits just like
  4259 Delsimps. Lower-case versions are also available.
  4260 
  4261 * HOL/Simplifier: The rule split_if is now part of the default
  4262 simpset. This means that the simplifier will eliminate all occurrences
  4263 of if-then-else in the conclusion of a goal. To prevent this, you can
  4264 either remove split_if completely from the default simpset by
  4265 `Delsplits [split_if]' or remove it in a specific call of the
  4266 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4267 other case splitting rules to/from the default simpset: every datatype
  4268 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4269 t is the name of the datatype).
  4270 
  4271 * Classical reasoner / Simplifier combination: new force_tac (and
  4272 derivatives Force_tac, force) combines rewriting and classical
  4273 reasoning (and whatever other tools) similarly to auto_tac, but is
  4274 aimed to solve the given subgoal completely.
  4275 
  4276 
  4277 *** General ***
  4278 
  4279 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4280 and `goalw': the theory is no longer needed as an explicit argument -
  4281 the current theory context is used; assumptions are no longer returned
  4282 at the ML-level unless one of them starts with ==> or !!; it is
  4283 recommended to convert to these new commands using isatool fixgoal
  4284 (backup your sources first!);
  4285 
  4286 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4287 the current theory context, and 'theory' to lookup stored theories;
  4288 
  4289 * new theory section 'locale' for declaring constants, assumptions and
  4290 definitions that have local scope;
  4291 
  4292 * new theory section 'nonterminals' for purely syntactic types;
  4293 
  4294 * new theory section 'setup' for generic ML setup functions
  4295 (e.g. package initialization);
  4296 
  4297 * the distribution now includes Isabelle icons: see
  4298 lib/logo/isabelle-{small,tiny}.xpm;
  4299 
  4300 * isatool install - install binaries with absolute references to
  4301 ISABELLE_HOME/bin;
  4302 
  4303 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4304 
  4305 * print mode 'emacs' reserved for Isamode;
  4306 
  4307 * support multiple print (ast) translations per constant name;
  4308 
  4309 * theorems involving oracles are now printed with a suffixed [!];
  4310 
  4311 
  4312 *** HOL ***
  4313 
  4314 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4315 
  4316 * HOL/inductive package reorganized and improved: now supports mutual
  4317 definitions such as
  4318 
  4319   inductive EVEN ODD
  4320     intrs
  4321       null "0 : EVEN"
  4322       oddI "n : EVEN ==> Suc n : ODD"
  4323       evenI "n : ODD ==> Suc n : EVEN"
  4324 
  4325 new theorem list "elims" contains an elimination rule for each of the
  4326 recursive sets; inductive definitions now handle disjunctive premises
  4327 correctly (also ZF);
  4328 
  4329 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4330 "mutual_induct" no longer exists - the induction rule is always
  4331 contained in "induct";
  4332 
  4333 
  4334 * HOL/datatype package re-implemented and greatly improved: now
  4335 supports mutually recursive datatypes such as
  4336 
  4337   datatype
  4338     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4339             | SUM ('a aexp) ('a aexp)
  4340             | DIFF ('a aexp) ('a aexp)
  4341             | NUM 'a
  4342   and
  4343     'a bexp = LESS ('a aexp) ('a aexp)
  4344             | AND ('a bexp) ('a bexp)
  4345             | OR ('a bexp) ('a bexp)
  4346 
  4347 as well as indirectly recursive datatypes such as
  4348 
  4349   datatype
  4350     ('a, 'b) term = Var 'a
  4351                   | App 'b ((('a, 'b) term) list)
  4352 
  4353 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4354 induction on mutually / indirectly recursive datatypes.
  4355 
  4356 Primrec equations are now stored in theory and can be accessed via
  4357 <function_name>.simps.
  4358 
  4359 INCOMPATIBILITIES:
  4360 
  4361   - Theories using datatypes must now have theory Datatype as an
  4362     ancestor.
  4363   - The specific <typename>.induct_tac no longer exists - use the
  4364     generic induct_tac instead.
  4365   - natE has been renamed to nat.exhaust - use exhaust_tac
  4366     instead of res_inst_tac ... natE. Note that the variable
  4367     names in nat.exhaust differ from the names in natE, this
  4368     may cause some "fragile" proofs to fail.
  4369   - The theorems split_<typename>_case and split_<typename>_case_asm
  4370     have been renamed to <typename>.split and <typename>.split_asm.
  4371   - Since default sorts of type variables are now handled correctly,
  4372     some datatype definitions may have to be annotated with explicit
  4373     sort constraints.
  4374   - Primrec definitions no longer require function name and type
  4375     of recursive argument.
  4376 
  4377 Consider using isatool fixdatatype to adapt your theories and proof
  4378 scripts to the new package (backup your sources first!).
  4379 
  4380 
  4381 * HOL/record package: considerably improved implementation; now
  4382 includes concrete syntax for record types, terms, updates; theorems
  4383 for surjective pairing and splitting !!-bound record variables; proof
  4384 support is as follows:
  4385 
  4386   1) standard conversions (selectors or updates applied to record
  4387 constructor terms) are part of the standard simpset;
  4388 
  4389   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4390 made part of standard simpset and claset via addIffs;
  4391 
  4392   3) a tactic for record field splitting (record_split_tac) is part of
  4393 the standard claset (addSWrapper);
  4394 
  4395 To get a better idea about these rules you may retrieve them via
  4396 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4397 the name of your record type.
  4398 
  4399 The split tactic 3) conceptually simplifies by the following rule:
  4400 
  4401   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4402 
  4403 Thus any record variable that is bound by meta-all will automatically
  4404 blow up into some record constructor term, consequently the
  4405 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4406 solve record problems automatically.
  4407 
  4408 
  4409 * reorganized the main HOL image: HOL/Integ and String loaded by
  4410 default; theory Main includes everything;
  4411 
  4412 * automatic simplification of integer sums and comparisons, using cancellation;
  4413 
  4414 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4415 
  4416 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4417 
  4418 * many new identities for unions, intersections, set difference, etc.;
  4419 
  4420 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4421 called split_if, split_split, split_sum_case and split_nat_case (to go
  4422 with add/delsplits);
  4423 
  4424 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4425 (?x::unit) = (); this is made part of the default simpset, which COULD
  4426 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4427 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4428 unit_abs_eta_conv is added in order to counter the effect of
  4429 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4430 %u.f();
  4431 
  4432 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4433 makes more sense);
  4434 
  4435 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4436   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4437   disjointness reasoning but breaking a few old proofs.
  4438 
  4439 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4440 to 'converse' from 'inverse' (for compatibility with ZF and some
  4441 literature);
  4442 
  4443 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4444 the well-founded relation;
  4445 
  4446 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4447     Compl A.  The "Compl" syntax remains available as input syntax for this
  4448     release ONLY.
  4449 
  4450 * HOL/Update: new theory of function updates:
  4451     f(a:=b) == %x. if x=a then b else f x
  4452 may also be iterated as in f(a:=b,c:=d,...);
  4453 
  4454 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4455 
  4456 * HOL/List:
  4457   - new function list_update written xs[i:=v] that updates the i-th
  4458     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4459   - new function `upt' written [i..j(] which generates the list
  4460     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4461     bound write [i..j], which is a shorthand for [i..j+1(].
  4462   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4463 
  4464 * HOL/Arith:
  4465   - removed 'pred' (predecessor) function;
  4466   - generalized some theorems about n-1;
  4467   - many new laws about "div" and "mod";
  4468   - new laws about greatest common divisors (see theory ex/Primes);
  4469 
  4470 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4471 instead of "inverse";
  4472 
  4473 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4474   of the multiset ordering;
  4475 
  4476 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4477   (not included by default);
  4478 
  4479 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4480 
  4481 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4482   programs, i.e. different program variables may have different types.
  4483 
  4484 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4485   [previously, this check worked only if the rewrite rule was unconditional]
  4486   Now rew can involve either definitions or equalities (either == or =).
  4487 
  4488 
  4489 *** ZF ***
  4490 
  4491 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4492   only the theorems proved on ZF.ML;
  4493 
  4494 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4495   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4496   disjointness reasoning but breaking a few old proofs.
  4497 
  4498 * ZF/Update: new theory of function updates
  4499     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4500   may also be iterated as in f(a:=b,c:=d,...);
  4501 
  4502 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4503 
  4504 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4505   [previously, this check worked only if the rewrite rule was unconditional]
  4506   Now rew can involve either definitions or equalities (either == or =).
  4507 
  4508 * case_tac provided for compatibility with HOL
  4509     (like the old excluded_middle_tac, but with subgoals swapped)
  4510 
  4511 
  4512 *** Internal programming interfaces ***
  4513 
  4514 * Pure: several new basic modules made available for general use, see
  4515 also src/Pure/README;
  4516 
  4517 * improved the theory data mechanism to support encapsulation (data
  4518 kind name replaced by private Object.kind, acting as authorization
  4519 key); new type-safe user interface via functor TheoryDataFun; generic
  4520 print_data function becomes basically useless;
  4521 
  4522 * removed global_names compatibility flag -- all theory declarations
  4523 are qualified by default;
  4524 
  4525 * module Pure/Syntax now offers quote / antiquote translation
  4526 functions (useful for Hoare logic etc. with implicit dependencies);
  4527 see HOL/ex/Antiquote for an example use;
  4528 
  4529 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4530 cterm -> thm;
  4531 
  4532 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4533 subgoal;
  4534 
  4535 * Display.print_goals function moved to Locale.print_goals;
  4536 
  4537 * standard print function for goals supports current_goals_markers
  4538 variable for marking begin of proof, end of proof, start of goal; the
  4539 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4540 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4541 for example;
  4542 
  4543 
  4544 
  4545 New in Isabelle98 (January 1998)
  4546 --------------------------------
  4547 
  4548 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4549 
  4550 * changed lexical syntax of terms / types: dots made part of long
  4551 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4552 
  4553 * simpset (and claset) reference variable replaced by functions
  4554 simpset / simpset_ref;
  4555 
  4556 * no longer supports theory aliases (via merge) and non-trivial
  4557 implicit merge of thms' signatures;
  4558 
  4559 * most internal names of constants changed due to qualified names;
  4560 
  4561 * changed Pure/Sequence interface (see Pure/seq.ML);
  4562 
  4563 
  4564 *** General Changes ***
  4565 
  4566 * hierachically structured name spaces (for consts, types, axms, thms
  4567 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4568 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4569 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4570 long_names for fully qualified output names; NOTE: ML programs
  4571 (special tactics, packages etc.) referring to internal names may have
  4572 to be adapted to cope with fully qualified names; in case of severe
  4573 backward campatibility problems try setting 'global_names' at compile
  4574 time to have enrything declared within a flat name space; one may also
  4575 fine tune name declarations in theories via the 'global' and 'local'
  4576 section;
  4577 
  4578 * reimplemented the implicit simpset and claset using the new anytype
  4579 data filed in signatures; references simpset:simpset ref etc. are
  4580 replaced by functions simpset:unit->simpset and
  4581 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4582 to patch your ML files accordingly;
  4583 
  4584 * HTML output now includes theory graph data for display with Java
  4585 applet or isatool browser; data generated automatically via isatool
  4586 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4587 
  4588 * defs may now be conditional; improved rewrite_goals_tac to handle
  4589 conditional equations;
  4590 
  4591 * defs now admits additional type arguments, using TYPE('a) syntax;
  4592 
  4593 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4594 creates a new theory node; implicit merge of thms' signatures is
  4595 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4596 transfer:theory->thm->thm in (rare) cases;
  4597 
  4598 * improved handling of draft signatures / theories; draft thms (and
  4599 ctyps, cterms) are automatically promoted to real ones;
  4600 
  4601 * slightly changed interfaces for oracles: admit many per theory, named
  4602 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4603 
  4604 * print_goals: optional output of const types (set show_consts and
  4605 show_types);
  4606 
  4607 * improved output of warnings (###) and errors (***);
  4608 
  4609 * subgoal_tac displays a warning if the new subgoal has type variables;
  4610 
  4611 * removed old README and Makefiles;
  4612 
  4613 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4614 
  4615 * removed obsolete init_pps and init_database;
  4616 
  4617 * deleted the obsolete tactical STATE, which was declared by
  4618     fun STATE tacfun st = tacfun st st;
  4619 
  4620 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4621 (which abbreviates $HOME);
  4622 
  4623 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4624 use isatool fixseq to adapt your ML programs (this works for fully
  4625 qualified references to the Sequence structure only!);
  4626 
  4627 * use_thy no longer requires writable current directory; it always
  4628 reloads .ML *and* .thy file, if either one is out of date;
  4629 
  4630 
  4631 *** Classical Reasoner ***
  4632 
  4633 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4634 tactics that use classical reasoning to simplify a subgoal without
  4635 splitting it into several subgoals;
  4636 
  4637 * Safe_tac: like safe_tac but uses the default claset;
  4638 
  4639 
  4640 *** Simplifier ***
  4641 
  4642 * added simplification meta rules:
  4643     (asm_)(full_)simplify: simpset -> thm -> thm;
  4644 
  4645 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4646 logics (again);
  4647 
  4648 * added prems argument to simplification procedures;
  4649 
  4650 * HOL, FOL, ZF: added infix function `addsplits':
  4651   instead of `<simpset> setloop (split_tac <thms>)'
  4652   you can simply write `<simpset> addsplits <thms>'
  4653 
  4654 
  4655 *** Syntax ***
  4656 
  4657 * TYPE('a) syntax for type reflection terms;
  4658 
  4659 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4660 
  4661 * pretty printer: changed order of mixfix annotation preference (again!);
  4662 
  4663 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4664 
  4665 
  4666 *** HOL ***
  4667 
  4668 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4669   with `addloop' of the simplifier to faciliate case splitting in premises.
  4670 
  4671 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4672 
  4673 * HOL/Auth: new protocol proofs including some for the Internet
  4674   protocol TLS;
  4675 
  4676 * HOL/Map: new theory of `maps' a la VDM;
  4677 
  4678 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4679 cancelling out common nat summands from =, <, <= (in)equalities, or
  4680 differences; simplification procedures nat_cancel_factor for
  4681 cancelling common factor from =, <, <= (in)equalities over natural
  4682 sums; nat_cancel contains both kinds of procedures, it is installed by
  4683 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4684 
  4685 * HOL/simplifier: terms of the form
  4686   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4687   are rewritten to
  4688   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4689   and those of the form
  4690   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4691   are rewritten to
  4692   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4693 
  4694 * HOL/datatype
  4695   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4696 
  4697   P(t_case f1 ... fn x) =
  4698      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4699         ...
  4700        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4701      )
  4702 
  4703   and a theorem `split_t_case_asm' of the form
  4704 
  4705   P(t_case f1 ... fn x) =
  4706     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4707         ...
  4708        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4709      )
  4710   which can be added to a simpset via `addsplits'. The existing theorems
  4711   expand_list_case and expand_option_case have been renamed to
  4712   split_list_case and split_option_case.
  4713 
  4714 * HOL/Arithmetic:
  4715   - `pred n' is automatically converted to `n-1'.
  4716     Users are strongly encouraged not to use `pred' any longer,
  4717     because it will disappear altogether at some point.
  4718   - Users are strongly encouraged to write "0 < n" rather than
  4719     "n ~= 0". Theorems and proof tools have been modified towards this
  4720     `standard'.
  4721 
  4722 * HOL/Lists:
  4723   the function "set_of_list" has been renamed "set" (and its theorems too);
  4724   the function "nth" now takes its arguments in the reverse order and
  4725   has acquired the infix notation "!" as in "xs!n".
  4726 
  4727 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4728 
  4729 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4730   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4731 
  4732 * HOL/record: extensible records with schematic structural subtyping
  4733 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4734 still lacks various theorems and concrete record syntax;
  4735 
  4736 
  4737 *** HOLCF ***
  4738 
  4739 * removed "axioms" and "generated by" sections;
  4740 
  4741 * replaced "ops" section by extended "consts" section, which is capable of
  4742   handling the continuous function space "->" directly;
  4743 
  4744 * domain package:
  4745   . proves theorems immediately and stores them in the theory,
  4746   . creates hierachical name space,
  4747   . now uses normal mixfix annotations (instead of cinfix...),
  4748   . minor changes to some names and values (for consistency),
  4749   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4750   . separator between mutual domain defs: changed "," to "and",
  4751   . improved handling of sort constraints;  now they have to
  4752     appear on the left-hand side of the equations only;
  4753 
  4754 * fixed LAM <x,y,zs>.b syntax;
  4755 
  4756 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4757 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4758 
  4759 
  4760 *** FOL and ZF ***
  4761 
  4762 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4763   with `addloop' of the simplifier to faciliate case splitting in premises.
  4764 
  4765 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4766 in HOL, they strip ALL and --> from proved theorems;
  4767 
  4768 
  4769 
  4770 New in Isabelle94-8 (May 1997)
  4771 ------------------------------
  4772 
  4773 *** General Changes ***
  4774 
  4775 * new utilities to build / run / maintain Isabelle etc. (in parts
  4776 still somewhat experimental); old Makefiles etc. still functional;
  4777 
  4778 * new 'Isabelle System Manual';
  4779 
  4780 * INSTALL text, together with ./configure and ./build scripts;
  4781 
  4782 * reimplemented type inference for greater efficiency, better error
  4783 messages and clean internal interface;
  4784 
  4785 * prlim command for dealing with lots of subgoals (an easier way of
  4786 setting goals_limit);
  4787 
  4788 
  4789 *** Syntax ***
  4790 
  4791 * supports alternative (named) syntax tables (parser and pretty
  4792 printer); internal interface is provided by add_modesyntax(_i);
  4793 
  4794 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4795 be used in conjunction with the Isabelle symbol font; uses the
  4796 "symbols" syntax table;
  4797 
  4798 * added token_translation interface (may translate name tokens in
  4799 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4800 the current print_mode); IMPORTANT: user print translation functions
  4801 are responsible for marking newly introduced bounds
  4802 (Syntax.mark_boundT);
  4803 
  4804 * token translations for modes "xterm" and "xterm_color" that display
  4805 names in bold, underline etc. or colors (which requires a color
  4806 version of xterm);
  4807 
  4808 * infixes may now be declared with names independent of their syntax;
  4809 
  4810 * added typed_print_translation (like print_translation, but may
  4811 access type of constant);
  4812 
  4813 
  4814 *** Classical Reasoner ***
  4815 
  4816 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4817 some limitations.  Blast_tac...
  4818   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4819   + ignores elimination rules that don't have the correct format
  4820         (the conclusion MUST be a formula variable)
  4821   + ignores types, which can make HOL proofs fail
  4822   + rules must not require higher-order unification, e.g. apply_type in ZF
  4823     [message "Function Var's argument not a bound variable" relates to this]
  4824   + its proof strategy is more general but can actually be slower
  4825 
  4826 * substitution with equality assumptions no longer permutes other
  4827 assumptions;
  4828 
  4829 * minor changes in semantics of addafter (now called addaltern); renamed
  4830 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4831 (and access functions for it);
  4832 
  4833 * improved combination of classical reasoner and simplifier:
  4834   + functions for handling clasimpsets
  4835   + improvement of addss: now the simplifier is called _after_ the
  4836     safe steps.
  4837   + safe variant of addss called addSss: uses safe simplifications
  4838     _during_ the safe steps. It is more complete as it allows multiple
  4839     instantiations of unknowns (e.g. with slow_tac).
  4840 
  4841 *** Simplifier ***
  4842 
  4843 * added interface for simplification procedures (functions that
  4844 produce *proven* rewrite rules on the fly, depending on current
  4845 redex);
  4846 
  4847 * ordering on terms as parameter (used for ordered rewriting);
  4848 
  4849 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4850 
  4851 * the solver is now split into a safe and an unsafe part.
  4852 This should be invisible for the normal user, except that the
  4853 functions setsolver and addsolver have been renamed to setSolver and
  4854 addSolver; added safe_asm_full_simp_tac;
  4855 
  4856 
  4857 *** HOL ***
  4858 
  4859 * a generic induction tactic `induct_tac' which works for all datatypes and
  4860 also for type `nat';
  4861 
  4862 * a generic case distinction tactic `exhaust_tac' which works for all
  4863 datatypes and also for type `nat';
  4864 
  4865 * each datatype comes with a function `size';
  4866 
  4867 * patterns in case expressions allow tuple patterns as arguments to
  4868 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4869 
  4870 * primrec now also works with type nat;
  4871 
  4872 * recdef: a new declaration form, allows general recursive functions to be
  4873 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4874 
  4875 * the constant for negation has been renamed from "not" to "Not" to
  4876 harmonize with FOL, ZF, LK, etc.;
  4877 
  4878 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4879 infinite lists;
  4880 
  4881 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4882 
  4883 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4884 problems in commutative rings, using axiomatic type classes for + and *;
  4885 
  4886 * more examples in HOL/MiniML and HOL/Auth;
  4887 
  4888 * more default rewrite rules for quantifiers, union/intersection;
  4889 
  4890 * a new constant `arbitrary == @x.False';
  4891 
  4892 * HOLCF/IOA replaces old HOL/IOA;
  4893 
  4894 * HOLCF changes: derived all rules and arities
  4895   + axiomatic type classes instead of classes
  4896   + typedef instead of faking type definitions
  4897   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4898   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4899   + eliminated the types void, one, tr
  4900   + use unit lift and bool lift (with translations) instead of one and tr
  4901   + eliminated blift from Lift3.thy (use Def instead of blift)
  4902   all eliminated rules are derived as theorems --> no visible changes ;
  4903 
  4904 
  4905 *** ZF ***
  4906 
  4907 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4908 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4909 as ZF_cs addSIs [equalityI];
  4910 
  4911 
  4912 
  4913 New in Isabelle94-7 (November 96)
  4914 ---------------------------------
  4915 
  4916 * allowing negative levels (as offsets) in prlev and choplev;
  4917 
  4918 * super-linear speedup for large simplifications;
  4919 
  4920 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4921 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4922 FAIL); can suppress it using the command Delsimps (ex_simps @
  4923 all_simps); De Morgan laws are also now included, by default;
  4924 
  4925 * improved printing of ==>  :  ~:
  4926 
  4927 * new object-logic "Sequents" adds linear logic, while replacing LK
  4928 and Modal (thanks to Sara Kalvala);
  4929 
  4930 * HOL/Auth: correctness proofs for authentication protocols;
  4931 
  4932 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4933 examples on HOL/Auth);
  4934 
  4935 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4936 the rewriter and classical reasoner simultaneously;
  4937 
  4938 * function uresult no longer returns theorems in "standard" format;
  4939 regain previous version by: val uresult = standard o uresult;
  4940 
  4941 
  4942 
  4943 New in Isabelle94-6
  4944 -------------------
  4945 
  4946 * oracles -- these establish an interface between Isabelle and trusted
  4947 external reasoners, which may deliver results as theorems;
  4948 
  4949 * proof objects (in particular record all uses of oracles);
  4950 
  4951 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4952 
  4953 * "constdefs" section in theory files;
  4954 
  4955 * "primrec" section (HOL) no longer requires names;
  4956 
  4957 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4958 
  4959 
  4960 
  4961 New in Isabelle94-5
  4962 -------------------
  4963 
  4964 * reduced space requirements;
  4965 
  4966 * automatic HTML generation from theories;
  4967 
  4968 * theory files no longer require "..." (quotes) around most types;
  4969 
  4970 * new examples, including two proofs of the Church-Rosser theorem;
  4971 
  4972 * non-curried (1994) version of HOL is no longer distributed;
  4973 
  4974 
  4975 
  4976 New in Isabelle94-4
  4977 -------------------
  4978 
  4979 * greatly reduced space requirements;
  4980 
  4981 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4982 
  4983 * searchable theorem database (see the section "Retrieving theorems" on
  4984 page 8 of the Reference Manual);
  4985 
  4986 * new examples, including Grabczewski's monumental case study of the
  4987 Axiom of Choice;
  4988 
  4989 * The previous version of HOL renamed to Old_HOL;
  4990 
  4991 * The new version of HOL (previously called CHOL) uses a curried syntax
  4992 for functions.  Application looks like f a b instead of f(a,b);
  4993 
  4994 * Mutually recursive inductive definitions finally work in HOL;
  4995 
  4996 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4997 translates to the operator "split";
  4998 
  4999 
  5000 
  5001 New in Isabelle94-3
  5002 -------------------
  5003 
  5004 * new infix operator, addss, allowing the classical reasoner to
  5005 perform simplification at each step of its search.  Example:
  5006         fast_tac (cs addss ss)
  5007 
  5008 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5009 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5010 look like (a,b) instead of <a,b>;
  5011 
  5012 * PLEASE NOTE: CHOL will eventually replace HOL!
  5013 
  5014 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5015 It translates to the operator "split".  A new theory of integers is available;
  5016 
  5017 * In ZF, integer numerals now denote two's-complement binary integers.
  5018 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5019 
  5020 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5021 of the Axiom of Choice;
  5022 
  5023 
  5024 
  5025 New in Isabelle94-2
  5026 -------------------
  5027 
  5028 * Significantly faster resolution;
  5029 
  5030 * the different sections in a .thy file can now be mixed and repeated
  5031 freely;
  5032 
  5033 * Database of theorems for FOL, HOL and ZF.  New
  5034 commands including qed, qed_goal and bind_thm store theorems in the database.
  5035 
  5036 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5037 a given theory (thms_of), or find out what theory a theorem was proved in
  5038 (theory_of_thm);
  5039 
  5040 * Bugs fixed in the inductive definition and datatype packages;
  5041 
  5042 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5043 and HOL_dup_cs obsolete;
  5044 
  5045 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5046 have been removed;
  5047 
  5048 * Simpler definition of function space in ZF;
  5049 
  5050 * new results about cardinal and ordinal arithmetic in ZF;
  5051 
  5052 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5053 types;
  5054 
  5055 
  5056 $Id$