NEWS
author paulson
Tue Aug 21 18:27:14 2007 +0200 (2007-08-21)
changeset 24385 ab62948281a9
parent 24342 a1d489e254ec
child 24422 c0b5ff9e9e4d
permissions -rw-r--r--
Deleted the partially-typed translation and the combinator code.
Minimize_applies now uses the same translation code, which handles both cases anyway.
     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 * Syntax: the scope for resolving ambiguities via type-inference is now
    50 limited to individual terms, instead of whole simultaneous
    51 specifications as before. This greatly reduces the complexity of the
    52 syntax module and improves flexibility by separating parsing and
    53 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
    54 'fixes' etc.) are required in rare situations.
    55 
    56 * Legacy goal package: reduced interface to the bare minimum required
    57 to keep existing proof scripts running.  Most other user-level
    58 functions are now part of the OldGoals structure, which is *not* open
    59 by default (consider isatool expandshort before open OldGoals).
    60 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    61 these tend to cause confusion about the actual goal (!) context being
    62 used here, which is not necessarily the same as the_context().
    63 
    64 * Command 'find_theorems': supports "*" wild-card in "name:"
    65 criterion; "with_dups" option.  Certain ProofGeneral versions might
    66 support a specific search form (see ProofGeneral/CHANGES).
    67 
    68 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    69 by default, which means that "prems" (and also "fixed variables") are
    70 suppressed from proof state output.  Note that the ProofGeneral
    71 settings mechanism allows to change and save options persistently, but
    72 older versions of Isabelle will fail to start up if a negative prems
    73 limit is imposed.
    74 
    75 * Local theory targets may be specified by non-nested blocks of
    76 ``context/locale/class ... begin'' followed by ``end''.  The body may
    77 contain definitions, theorems etc., including any derived mechanism
    78 that has been implemented on top of these primitives.  This concept
    79 generalizes the existing ``theorem (in ...)'' towards more versatility
    80 and scalability.
    81 
    82 * Proof General interface: proper undo of final 'end' command;
    83 discontinued Isabelle/classic mode (ML proof scripts).
    84 
    85 
    86 *** Document preparation ***
    87 
    88 * Added antiquotation @{theory name} which prints the given name,
    89 after checking that it refers to a valid ancestor theory in the
    90 current context.
    91 
    92 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    93 check the given source text as ML type/structure, printing verbatim.
    94 
    95 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    96 "c args == rhs" given in the current context.  (Any number of
    97 arguments may be given on the LHS.)
    98 
    99 
   100 
   101 *** Pure ***
   102 
   103 * code generator: consts in 'consts_code' Isar commands are now referred
   104   to by usual term syntax (including optional type annotations).
   105 
   106 * code generator: 
   107   - Isar 'definition's, 'constdef's and primitive instance definitions are added
   108     explicitly to the table of defining equations
   109   - primitive definitions are not used as defining equations by default any longer
   110   - defining equations are now definitly restricted to meta "==" and object
   111         equality "="
   112   - HOL theories have been adopted accordingly
   113 
   114 * class_package.ML offers a combination of axclasses and locales to
   115 achieve Haskell-like type classes in Isabelle.  See
   116 HOL/ex/Classpackage.thy for examples.
   117 
   118 * Yet another code generator framework allows to generate executable
   119 code for ML and Haskell (including "class"es).  A short usage sketch:
   120 
   121     internal compilation:
   122         code_gen <list of constants (term syntax)> in SML
   123     writing SML code to a file:
   124         code_gen <list of constants (term syntax)> in SML <filename>
   125     writing OCaml code to a file:
   126         code_gen <list of constants (term syntax)> in OCaml <filename>
   127     writing Haskell code to a bunch of files:
   128         code_gen <list of constants (term syntax)> in Haskell <filename>
   129 
   130 Reasonable default setup of framework in HOL/Main.
   131 
   132 Theorem attributs for selecting and transforming function equations theorems:
   133 
   134     [code fun]:        select a theorem as function equation for a specific constant
   135     [code fun del]:    deselect a theorem as function equation for a specific constant
   136     [code inline]:     select an equation theorem for unfolding (inlining) in place
   137     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   138 
   139 User-defined serializations (target in {SML, OCaml, Haskell}):
   140 
   141     code_const <and-list of constants (term syntax)>
   142       {(target) <and-list of const target syntax>}+
   143 
   144     code_type <and-list of type constructors>
   145       {(target) <and-list of type target syntax>}+
   146 
   147     code_instance <and-list of instances>
   148       {(target)}+
   149         where instance ::= <type constructor> :: <class>
   150 
   151     code_class <and_list of classes>
   152       {(target) <and-list of class target syntax>}+
   153         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   154 
   155 code_instance and code_class only apply to target Haskell.
   156 
   157 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   158 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   159 
   160 * Command 'no_translations' removes translation rules from theory
   161 syntax.
   162 
   163 * Overloaded definitions are now actually checked for acyclic
   164 dependencies.  The overloading scheme is slightly more general than
   165 that of Haskell98, although Isabelle does not demand an exact
   166 correspondence to type class and instance declarations.
   167 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   168 exotic versions of overloading -- at the discretion of the user!
   169 
   170 Polymorphic constants are represented via type arguments, i.e. the
   171 instantiation that matches an instance against the most general
   172 declaration given in the signature.  For example, with the declaration
   173 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   174 as c(nat).  Overloading is essentially simultaneous structural
   175 recursion over such type arguments.  Incomplete specification patterns
   176 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   177 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   178 Command 'print_theory' outputs the normalized system of recursive
   179 equations, see section "definitions".
   180 
   181 * Configuration options are maintained within the theory or proof
   182 context (with name and type bool/int/string), providing a very simple
   183 interface to a poor-man's version of general context data.  Tools may
   184 declare options in ML (e.g. using Attrib.config_int) and then refer to
   185 these values using Config.get etc.  Users may change options via an
   186 associated attribute of the same name.  This form of context
   187 declaration works particularly well with commands 'declare' or
   188 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   189 very easy to avoid global references, which would not observe Isar
   190 toplevel undo/redo and fail to work with multithreading.
   191 
   192 Various global ML references of Pure and HOL have been turned into
   193 configuration options:
   194 
   195   Unify.search_bound		unify_search_bound
   196   Unify.trace_bound		unify_trace_bound
   197   Unify.trace_simp		unify_trace_simp
   198   Unify.trace_types		unify_trace_types
   199   Simplifier.simp_depth_limit	simp_depth_limit
   200   Blast.depth_limit		blast_depth_limit
   201   DatatypeProp.dtK		datatype_distinctness_limit
   202   fast_arith_neq_limit  	fast_arith_neq_limit
   203   fast_arith_split_limit	fast_arith_split_limit
   204 
   205 * Named collections of theorems may be easily installed as context
   206 data using the functor NamedThmsFun (see
   207 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   208 attributes; there is also a toplevel print command.  This facility is
   209 just a common case of general context data, which is the preferred way
   210 for anything more complex than just a list of facts in canonical
   211 order.
   212 
   213 * Isar: command 'declaration' augments a local theory by generic
   214 declaration functions written in ML.  This enables arbitrary content
   215 being added to the context, depending on a morphism that tells the
   216 difference of the original declaration context wrt. the application
   217 context encountered later on.
   218 
   219 * Isar: proper interfaces for simplification procedures.  Command
   220 'simproc_setup' declares named simprocs (with match patterns, and body
   221 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   222 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   223 
   224 * Isar: an extra pair of brackets around attribute declarations
   225 abbreviates a theorem reference involving an internal dummy fact,
   226 which will be ignored later --- only the effect of the attribute on
   227 the background context will persist.  This form of in-place
   228 declarations is particularly useful with commands like 'declare' and
   229 'using', for example ``have A using [[simproc a]] by simp''.
   230 
   231 * Isar: method "assumption" (and implicit closing of subproofs) now
   232 takes simple non-atomic goal assumptions into account: after applying
   233 an assumption as a rule the resulting subgoals are solved by atomic
   234 assumption steps.  This is particularly useful to finish 'obtain'
   235 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   236 without referring to the original premise "!!x. P x ==> thesis" in the
   237 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   238 more permissive.
   239 
   240 * Isar: implicit use of prems from the Isar proof context is
   241 considered a legacy feature.  Common applications like ``have A .''
   242 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   243 referencing facts explicitly here improves readability and
   244 maintainability of proof texts.
   245 
   246 * Isar: improper proof element 'guess' is like 'obtain', but derives
   247 the obtained context from the course of reasoning!  For example:
   248 
   249   assume "EX x y. A x & B y"   -- "any previous fact"
   250   then guess x and y by clarify
   251 
   252 This technique is potentially adventurous, depending on the facts and
   253 proof tools being involved here.
   254 
   255 * Isar: known facts from the proof context may be specified as literal
   256 propositions, using ASCII back-quote syntax.  This works wherever
   257 named facts used to be allowed so far, in proof commands, proof
   258 methods, attributes etc.  Literal facts are retrieved from the context
   259 according to unification of type and term parameters.  For example,
   260 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   261 theorems in the current context, then these are valid literal facts:
   262 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   263 
   264 There is also a proof method "fact" which does the same composition
   265 for explicit goal states, e.g. the following proof texts coincide with
   266 certain special cases of literal facts:
   267 
   268   have "A" by fact                 ==  note `A`
   269   have "A ==> B" by fact           ==  note `A ==> B`
   270   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   271   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   272 
   273 * Isar: ":" (colon) is no longer a symbolic identifier character in
   274 outer syntax.  Thus symbolic identifiers may be used without
   275 additional white space in declarations like this: ``assume *: A''.
   276 
   277 * Isar: 'print_facts' prints all local facts of the current context,
   278 both named and unnamed ones.
   279 
   280 * Isar: 'def' now admits simultaneous definitions, e.g.:
   281 
   282   def x == "t" and y == "u"
   283 
   284 * Isar: added command 'unfolding', which is structurally similar to
   285 'using', but affects both the goal state and facts by unfolding given
   286 rewrite rules.  Thus many occurrences of the 'unfold' method or
   287 'unfolded' attribute may be replaced by first-class proof text.
   288 
   289 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   290 and command 'unfolding' now all support object-level equalities
   291 (potentially conditional).  The underlying notion of rewrite rule is
   292 analogous to the 'rule_format' attribute, but *not* that of the
   293 Simplifier (which is usually more generous).
   294 
   295 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   296 premises of a theorem by n. Useful in conjunction with drule.
   297 
   298 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   299 method expression within a sandbox consisting of the first N
   300 sub-goals, which need to exist.  For example, ``simp_all [3]''
   301 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   302 simplifies all new goals that emerge from applying rule foo to the
   303 originally first one.
   304 
   305 * Isar: schematic goals are no longer restricted to higher-order
   306 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   307 expected.
   308 
   309 * Isar: the conclusion of a long theorem statement is now either
   310 'shows' (a simultaneous conjunction, as before), or 'obtains'
   311 (essentially a disjunction of cases with local parameters and
   312 assumptions).  The latter allows to express general elimination rules
   313 adequately; in this notation common elimination rules look like this:
   314 
   315   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   316     assumes "EX x. P x"
   317     obtains x where "P x"
   318 
   319   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   320     assumes "A & B"
   321     obtains A and B
   322 
   323   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   324     assumes "A | B"
   325     obtains
   326       A
   327     | B
   328 
   329 The subsequent classical rules even refer to the formal "thesis"
   330 explicitly:
   331 
   332   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   333     obtains "~ thesis"
   334 
   335   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   336     obtains "thesis ==> something"
   337 
   338 The actual proof of an 'obtains' statement is analogous to that of the
   339 Isar proof element 'obtain', only that there may be several cases.
   340 Optional case names may be specified in parentheses; these will be
   341 available both in the present proof and as annotations in the
   342 resulting rule, for later use with the 'cases' method (cf. attribute
   343 case_names).
   344 
   345 * Isar: the assumptions of a long theorem statement are available as
   346 "assms" fact in the proof context.  This is more appropriate than the
   347 (historical) "prems", which refers to all assumptions of the current
   348 context, including those from the target locale, proof body etc.
   349 
   350 * Isar: 'print_statement' prints theorems from the current theory or
   351 proof context in long statement form, according to the syntax of a
   352 top-level lemma.
   353 
   354 * Isar: 'obtain' takes an optional case name for the local context
   355 introduction rule (default "that").
   356 
   357 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   358 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   359 to occur.
   360 
   361 * Pure: syntax "CONST name" produces a fully internalized constant
   362 according to the current context.  This is particularly useful for
   363 syntax translations that should refer to internal constant
   364 representations independently of name spaces.
   365 
   366 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   367 instead of "FOO ". This allows multiple binder declarations to coexist
   368 in the same context.  INCOMPATIBILITY.
   369 
   370 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   371 primitive that also works in a locale context (both for constants and
   372 fixed variables).  Type declaration and internal syntactic
   373 representation of given constants retrieved from the context.
   374 
   375 * Isar/locales: new derived specification elements 'axiomatization',
   376 'definition', 'abbreviation', which support type-inference, admit
   377 object-level specifications (equality, equivalence).  See also the
   378 isar-ref manual.  Examples:
   379 
   380   axiomatization
   381     eq  (infix "===" 50) where
   382     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   383 
   384   definition "f x y = x + y + 1"
   385   definition g where "g x = f x x"
   386 
   387   abbreviation
   388     neq  (infix "=!=" 50) where
   389     "x =!= y == ~ (x === y)"
   390 
   391 These specifications may be also used in a locale context.  Then the
   392 constants being introduced depend on certain fixed parameters, and the
   393 constant name is qualified by the locale base name.  An internal
   394 abbreviation takes care for convenient input and output, making the
   395 parameters implicit and using the original short name.  See also
   396 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   397 entities from a monomorphic theory.
   398 
   399 Presently, abbreviations are only available 'in' a target locale, but
   400 not inherited by general import expressions.  Also note that
   401 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   402 'translations' in common applications.
   403 
   404 Concrete syntax is attached to specified constants in internal form,
   405 independently of name spaces.  The parse tree representation is
   406 slightly different -- use 'notation' instead of raw 'syntax', and
   407 'translations' with explicit "CONST" markup to accommodate this.
   408 
   409 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   410 the current context.  Print mode "no_abbrevs" prevents inversion of
   411 abbreviations on output.
   412 
   413 * Isar/locales: improved parameter handling:
   414 - use of locales "var" and "struct" no longer necessary;
   415 - parameter renamings are no longer required to be injective.
   416   This enables, for example, to define a locale for endomorphisms thus:
   417   locale endom = homom mult mult h.
   418 
   419 * Isar/locales: changed the way locales with predicates are defined.
   420 Instead of accumulating the specification, the imported expression is
   421 now an interpretation.  INCOMPATIBILITY: different normal form of
   422 locale expressions.  In particular, in interpretations of locales with
   423 predicates, goals repesenting already interpreted fragments are not
   424 removed automatically.  Use methods `intro_locales' and
   425 `unfold_locales'; see below.
   426 
   427 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   428 provide backward reasoning on locales predicates.  The methods are
   429 aware of interpretations and discharge corresponding goals.
   430 `intro_locales' is less aggressive then `unfold_locales' and does not
   431 unfold predicates to assumptions.
   432 
   433 * Isar/locales: the order in which locale fragments are accumulated
   434 has changed.  This enables to override declarations from fragments due
   435 to interpretations -- for example, unwanted simp rules.
   436 
   437 * Isar/locales: interpretation in theories and proof contexts has been
   438 extended.  One may now specify (and prove) equations, which are
   439 unfolded in interpreted theorems.  This is useful for replacing
   440 defined concepts (constants depending on locale parameters) by
   441 concepts already existing in the target context.  Example:
   442 
   443   interpretation partial_order ["op <= :: [int, int] => bool"]
   444     where "partial_order.less (op <=) (x::int) y = (x < y)"
   445 
   446 Typically, the constant `partial_order.less' is created by a definition
   447 specification element in the context of locale partial_order.
   448 
   449 * Provers/induct: improved internal context management to support
   450 local fixes and defines on-the-fly.  Thus explicit meta-level
   451 connectives !! and ==> are rarely required anymore in inductive goals
   452 (using object-logic connectives for this purpose has been long
   453 obsolete anyway).  The subsequent proof patterns illustrate advanced
   454 techniques of natural induction; general datatypes and inductive sets
   455 work analogously (see also src/HOL/Lambda for realistic examples).
   456 
   457 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   458 parameters:
   459 
   460   lemma
   461     fixes n :: nat and x :: 'a
   462     assumes a: "A n x"
   463     shows "P n x"
   464     using a                     -- {* make induct insert fact a *}
   465   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   466     case 0
   467     show ?case sorry
   468   next
   469     case (Suc n)
   470     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   471     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   472     show ?case sorry
   473   qed
   474 
   475 (2) This is how to perform induction over ``expressions of a certain
   476 form'', using a locally defined inductive parameter n == "a x"
   477 together with strengthening (the latter is usually required to get
   478 sufficiently flexible induction hypotheses):
   479 
   480   lemma
   481     fixes a :: "'a => nat"
   482     assumes a: "A (a x)"
   483     shows "P (a x)"
   484     using a
   485   proof (induct n == "a x" arbitrary: x)
   486     ...
   487 
   488 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   489 particular technique.
   490 
   491 (3) This is how to perform existential reasoning ('obtains' or
   492 'obtain') by induction, while avoiding explicit object-logic
   493 encodings:
   494 
   495   lemma
   496     fixes n :: nat
   497     obtains x :: 'a where "P n x" and "Q n x"
   498   proof (induct n arbitrary: thesis)
   499     case 0
   500     obtain x where "P 0 x" and "Q 0 x" sorry
   501     then show thesis by (rule 0)
   502   next
   503     case (Suc n)
   504     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   505     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   506     then show thesis by (rule Suc.prems)
   507   qed
   508 
   509 Here the 'arbitrary: thesis' specification essentially modifies the
   510 scope of the formal thesis parameter, in order to the get the whole
   511 existence statement through the induction as expected.
   512 
   513 * Provers/induct: mutual induction rules are now specified as a list
   514 of rule sharing the same induction cases.  HOL packages usually
   515 provide foo_bar.inducts for mutually defined items foo and bar
   516 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   517 specify mutual induction rules differently, i.e. like this:
   518 
   519   (induct rule: foo_bar.inducts)
   520   (induct set: foo bar)
   521   (induct type: foo bar)
   522 
   523 The ML function ProjectRule.projections turns old-style rules into the
   524 new format.
   525 
   526 * Provers/induct: improved handling of simultaneous goals.  Instead of
   527 introducing object-level conjunction, the statement is now split into
   528 several conclusions, while the corresponding symbolic cases are
   529 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   530 explicitly.  For example:
   531 
   532   lemma
   533     fixes n :: nat
   534     shows "P n" and "Q n"
   535   proof (induct n)
   536     case 0 case 1
   537     show "P 0" sorry
   538   next
   539     case 0 case 2
   540     show "Q 0" sorry
   541   next
   542     case (Suc n) case 1
   543     note `P n` and `Q n`
   544     show "P (Suc n)" sorry
   545   next
   546     case (Suc n) case 2
   547     note `P n` and `Q n`
   548     show "Q (Suc n)" sorry
   549   qed
   550 
   551 The split into subcases may be deferred as follows -- this is
   552 particularly relevant for goal statements with local premises.
   553 
   554   lemma
   555     fixes n :: nat
   556     shows "A n ==> P n" and "B n ==> Q n"
   557   proof (induct n)
   558     case 0
   559     {
   560       case 1
   561       note `A 0`
   562       show "P 0" sorry
   563     next
   564       case 2
   565       note `B 0`
   566       show "Q 0" sorry
   567     }
   568   next
   569     case (Suc n)
   570     note `A n ==> P n` and `B n ==> Q n`
   571     {
   572       case 1
   573       note `A (Suc n)`
   574       show "P (Suc n)" sorry
   575     next
   576       case 2
   577       note `B (Suc n)`
   578       show "Q (Suc n)" sorry
   579     }
   580   qed
   581 
   582 If simultaneous goals are to be used with mutual rules, the statement
   583 needs to be structured carefully as a two-level conjunction, using
   584 lists of propositions separated by 'and':
   585 
   586   lemma
   587     shows "a : A ==> P1 a"
   588           "a : A ==> P2 a"
   589       and "b : B ==> Q1 b"
   590           "b : B ==> Q2 b"
   591           "b : B ==> Q3 b"
   592   proof (induct set: A B)
   593 
   594 * Provers/induct: support coinduction as well.  See
   595 src/HOL/Library/Coinductive_List.thy for various examples.
   596 
   597 * Attribute "symmetric" produces result with standardized schematic
   598 variables (index 0).  Potential INCOMPATIBILITY.
   599 
   600 * Simplifier: by default the simplifier trace only shows top level
   601 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   602 default. Thus there is less danger of being flooded by the trace. The
   603 trace indicates where parts have been suppressed.
   604   
   605 * Provers/classical: removed obsolete classical version of elim_format
   606 attribute; classical elim/dest rules are now treated uniformly when
   607 manipulating the claset.
   608 
   609 * Provers/classical: stricter checks to ensure that supplied intro,
   610 dest and elim rules are well-formed; dest and elim rules must have at
   611 least one premise.
   612 
   613 * Provers/classical: attributes dest/elim/intro take an optional
   614 weight argument for the rule (just as the Pure versions).  Weights are
   615 ignored by automated tools, but determine the search order of single
   616 rule steps.
   617 
   618 * Syntax: input syntax now supports dummy variable binding "%_. b",
   619 where the body does not mention the bound variable.  Note that dummy
   620 patterns implicitly depend on their context of bounds, which makes
   621 "{_. _}" match any set comprehension as expected.  Potential
   622 INCOMPATIBILITY -- parse translations need to cope with syntactic
   623 constant "_idtdummy" in the binding position.
   624 
   625 * Syntax: removed obsolete syntactic constant "_K" and its associated
   626 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   627 for example "A -> B" => "Pi A (%_. B)".
   628 
   629 * Pure: 'class_deps' command visualizes the subclass relation, using
   630 the graph browser tool.
   631 
   632 * Pure: 'print_theory' now suppresses entities with internal name
   633 (trailing "_") by default; use '!' option for full details.
   634 
   635 
   636 *** HOL ***
   637 
   638 * theory Finite_Set: "name-space" locales Lattice, Distrib_lattice, Linorder etc.
   639 have disappeared; operations defined in terms of fold_set now are named
   640 Inf_fin, Sup_fin.  INCOMPATIBILITY.
   641 
   642 * HOL-Word:
   643   New extensive library and type for generic, fixed size machine
   644   words, with arithemtic, bit-wise, shifting and rotating operations,
   645   reflection into int, nat, and bool lists, automation for linear
   646   arithmetic (by automatic reflection into nat or int), including
   647   lemmas on overflow and monotonicity. Instantiated to all appropriate
   648   arithmetic type classes, supporting automatic simplification of
   649   numerals on all operations. Jointly developed by NICTA, Galois, and
   650   PSU.
   651 
   652 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   653 
   654 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   655 
   656 * Code generator library theories:
   657   * Pretty_Int represents HOL integers by big integer literals in target
   658     languages.
   659   * Pretty_Char represents HOL characters by character literals in target
   660     languages.
   661   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   662     codes; includes Pretty_Int.
   663   * Executable_Set allows to generate code for finite sets using lists.
   664   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   665     denominator).
   666   * Executable_Real implements a subset of real numbers, namly those
   667     representable by rational numbers.
   668   * Efficient_Nat implements natural numbers by integers, which in general will
   669     result in higher efficency; pattern matching with 0/Suc is eliminated;
   670     includes Pretty_Int.
   671   * ML_String provides an additional datatype ml_string; in the HOL default
   672     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   673     of type ml_string are mapped to strings in SML.
   674   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   675     built-in integers.
   676 
   677 * New package for inductive predicates
   678 
   679   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   680 
   681     inductive
   682       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   683       for z_1 :: U_1 and ... and z_n :: U_m
   684     where
   685       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   686     | ...
   687 
   688   rather than
   689 
   690     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   691 
   692     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   693     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   694 
   695     inductive "s z_1 ... z_m"
   696     intros
   697       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   698       ...
   699 
   700   For backward compatibility, there is a wrapper allowing inductive
   701   sets to be defined with the new package via
   702 
   703     inductive_set
   704       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   705       for z_1 :: U_1 and ... and z_n :: U_m
   706     where
   707       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   708     | ...
   709 
   710   or
   711 
   712     inductive_set
   713       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   714       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   715       for z_1 :: U_1 and ... and z_n :: U_m
   716     where
   717       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   718     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   719     | ...
   720 
   721   if the additional syntax "p ..." is required.
   722 
   723   Many examples can be found in the subdirectories Auth, Bali, Induct,
   724   or MicroJava.
   725 
   726   INCOMPATIBILITIES:
   727 
   728   - Since declaration and definition of inductive sets or predicates
   729     is no longer separated, abbreviations involving the newly introduced
   730     sets or predicates must be specified together with the introduction
   731     rules after the "where" keyword (see example above), rather than before
   732     the actual inductive definition.
   733 
   734   - The variables in induction and elimination rules are now quantified
   735     in the order of their occurrence in the introduction rules, rather than
   736     in alphabetical order. Since this may break some proofs, these proofs
   737     either have to be repaired, e.g. by reordering the variables
   738     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   739 
   740       case (rule_i a_i_1 ... a_i_{k_i})
   741 
   742     or the old order of quantification has to be restored by explicitly adding
   743     meta-level quantifiers in the introduction rules, i.e.
   744 
   745       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   746 
   747   - The format of the elimination rules is now
   748 
   749       p z_1 ... z_m x_1 ... x_n ==>
   750         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   751         ==> ... ==> P
   752 
   753     for predicates and
   754 
   755       (x_1, ..., x_n) : s z_1 ... z_m ==>
   756         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   757         ==> ... ==> P
   758 
   759     for sets rather than
   760 
   761       x : s z_1 ... z_m ==>
   762         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   763         ==> ... ==> P
   764 
   765     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   766     or simplification with the split_paired_all rule) before the above elimination
   767     rule is applicable.
   768 
   769   - The elimination or case analysis rules for (mutually) inductive sets or
   770     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   771     "p_1_..._p_k.elims" is no longer available.
   772 
   773 * Method "metis" proves goals by applying the Metis general-purpose
   774 resolution prover.  Examples are in the directory MetisExamples.  See
   775 also http://gilith.com/software/metis/
   776   
   777 * Command 'sledgehammer' invokes external automatic theorem provers as
   778 background processes.  It generates calls to the "metis" method if
   779 successful. These can be pasted into the proof.  Users do not have to
   780 wait for the automatic provers to return.
   781 
   782 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   783   take their order into account, like in functional programming.
   784   Internally, this is translated into nested case-expressions; missing cases
   785   are added and mapped to the predefined constant "undefined". In complicated
   786   cases printing may no longer show the original input but the internal
   787   form. Lambda-abstractions allow the same form of pattern matching:
   788   "% pat1 => e1 | ..." is an abbreviation for
   789   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   790 
   791 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   792   is an abbreviation for "of_nat :: nat => int". The simplification rules
   793   for "of_nat" have been changed to work like "int" did previously.
   794   (potential INCOMPATIBILITY)
   795   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   796   - of_nat_diff and of_nat_mult are no longer default simp rules
   797 
   798 * Method "algebra" solves polynomial equations over (semi)rings using
   799   Groebner bases. The (semi)ring structure is defined by locales and
   800   the tool setup depends on that generic context. Installing the
   801   method for a specific type involves instantiating the locale and
   802   possibly adding declarations for computation on the coefficients.
   803   The method is already instantiated for natural numbers and for the
   804   axiomatic class of idoms with numerals.  See also the paper by
   805   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   806   underlying this architecture of context-aware proof-tools.
   807 
   808 * constant "List.op @" now named "List.append".  Use ML antiquotations
   809 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   810 possible incompatibilities when working on ML level.
   811 
   812 * Constant renames due to introduction of canonical name prefixing for
   813   class package:
   814 
   815     HOL.abs ~> HOL.minus_class.abs
   816     HOL.divide ~> HOL.divide_class.divide
   817     Nat.power ~> Nat.power_class.power
   818     Nat.size ~> Nat.size_class.size
   819     Numeral.number_of ~> Numeral.number_class.number_of
   820     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   821     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   822 
   823 * Rudimentary class target mechanism involves constant renames:
   824 
   825     Orderings.min ~> Orderings.ord_class.min
   826     Orderings.max ~> Orderings.ord_class.max
   827 
   828 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   829 
   830 * new constant "undefined" with axiom "undefined x = undefined"
   831 
   832 * new class "default" with associated constant "default"
   833 
   834 * new function listsum :: 'a list => 'a for arbitrary monoids.
   835   Special syntax: "SUM x <- xs. f x" (and latex variants)
   836 
   837 * new (input only) syntax for Haskell-like list comprehension, eg
   838   [(x,y). x <- xs, y <- ys, x ~= y]
   839   For details see List.thy.
   840 
   841 * The special syntax for function "filter" has changed from [x : xs. P] to
   842   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   843   and for uniformity. INCOMPATIBILITY
   844 
   845 * Lemma "set_take_whileD" renamed to "set_takeWhileD"
   846 
   847 * New lemma collection field_simps (an extension of ring_simps)
   848   for manipulating (in)equations involving division. Multiplies
   849   with all denominators that can be proved to be non-zero (in equations)
   850   or positive/negative (in inequations).
   851 
   852 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   853   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   854   Removed lemmas field_xyz in Ring_and_Field
   855   because they were subsumed by lemmas xyz.
   856 INCOMPATIBILITY.
   857 
   858 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   859   when generating code.
   860 
   861 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   862   when generating code.
   863 
   864 * Library/Commutative_Ring.thy: switched from recdef to function package;
   865   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   866 
   867 * Some steps towards more uniform lattice theory development in HOL.
   868 
   869     constants "meet" and "join" now named "inf" and "sup"
   870     constant "Meet" now named "Inf"
   871 
   872     classes "meet_semilorder" and "join_semilorder" now named
   873       "lower_semilattice" and "upper_semilattice"
   874     class "lorder" now named "lattice"
   875     class "comp_lat" now named "complete_lattice"
   876 
   877     Instantiation of lattice classes allows explicit definitions
   878     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   879 
   880   INCOMPATIBILITY.  Theorem renames:
   881 
   882     meet_left_le            ~> inf_le1
   883     meet_right_le           ~> inf_le2
   884     join_left_le            ~> sup_ge1
   885     join_right_le           ~> sup_ge2
   886     meet_join_le            ~> inf_sup_ord
   887     le_meetI                ~> le_infI
   888     join_leI                ~> le_supI
   889     le_meet                 ~> le_inf_iff
   890     le_join                 ~> ge_sup_conv
   891     meet_idempotent         ~> inf_idem
   892     join_idempotent         ~> sup_idem
   893     meet_comm               ~> inf_commute
   894     join_comm               ~> sup_commute
   895     meet_leI1               ~> le_infI1
   896     meet_leI2               ~> le_infI2
   897     le_joinI1               ~> le_supI1
   898     le_joinI2               ~> le_supI2
   899     meet_assoc              ~> inf_assoc
   900     join_assoc              ~> sup_assoc
   901     meet_left_comm          ~> inf_left_commute
   902     meet_left_idempotent    ~> inf_left_idem
   903     join_left_comm          ~> sup_left_commute
   904     join_left_idempotent    ~> sup_left_idem
   905     meet_aci                ~> inf_aci
   906     join_aci                ~> sup_aci
   907     le_def_meet             ~> le_iff_inf
   908     le_def_join             ~> le_iff_sup
   909     join_absorp2            ~> sup_absorb2
   910     join_absorp1            ~> sup_absorb1
   911     meet_absorp1            ~> inf_absorb1
   912     meet_absorp2            ~> inf_absorb2
   913     meet_join_absorp        ~> inf_sup_absorb
   914     join_meet_absorp        ~> sup_inf_absorb
   915     distrib_join_le         ~> distrib_sup_le
   916     distrib_meet_le         ~> distrib_inf_le
   917 
   918     add_meet_distrib_left   ~> add_inf_distrib_left
   919     add_join_distrib_left   ~> add_sup_distrib_left
   920     is_join_neg_meet        ~> is_join_neg_inf
   921     is_meet_neg_join        ~> is_meet_neg_sup
   922     add_meet_distrib_right  ~> add_inf_distrib_right
   923     add_join_distrib_right  ~> add_sup_distrib_right
   924     add_meet_join_distribs  ~> add_sup_inf_distribs
   925     join_eq_neg_meet        ~> sup_eq_neg_inf
   926     meet_eq_neg_join        ~> inf_eq_neg_sup
   927     add_eq_meet_join        ~> add_eq_inf_sup
   928     meet_0_imp_0            ~> inf_0_imp_0
   929     join_0_imp_0            ~> sup_0_imp_0
   930     meet_0_eq_0             ~> inf_0_eq_0
   931     join_0_eq_0             ~> sup_0_eq_0
   932     neg_meet_eq_join        ~> neg_inf_eq_sup
   933     neg_join_eq_meet        ~> neg_sup_eq_inf
   934     join_eq_if              ~> sup_eq_if
   935 
   936     mono_meet               ~> mono_inf
   937     mono_join               ~> mono_sup
   938     meet_bool_eq            ~> inf_bool_eq
   939     join_bool_eq            ~> sup_bool_eq
   940     meet_fun_eq             ~> inf_fun_eq
   941     join_fun_eq             ~> sup_fun_eq
   942     meet_set_eq             ~> inf_set_eq
   943     join_set_eq             ~> sup_set_eq
   944     meet1_iff               ~> inf1_iff
   945     meet2_iff               ~> inf2_iff
   946     meet1I                  ~> inf1I
   947     meet2I                  ~> inf2I
   948     meet1D1                 ~> inf1D1
   949     meet2D1                 ~> inf2D1
   950     meet1D2                 ~> inf1D2
   951     meet2D2                 ~> inf2D2
   952     meet1E                  ~> inf1E
   953     meet2E                  ~> inf2E
   954     join1_iff               ~> sup1_iff
   955     join2_iff               ~> sup2_iff
   956     join1I1                 ~> sup1I1
   957     join2I1                 ~> sup2I1
   958     join1I1                 ~> sup1I1
   959     join2I2                 ~> sup1I2
   960     join1CI                 ~> sup1CI
   961     join2CI                 ~> sup2CI
   962     join1E                  ~> sup1E
   963     join2E                  ~> sup2E
   964 
   965     is_meet_Meet            ~> is_meet_Inf
   966     Meet_bool_def           ~> Inf_bool_def
   967     Meet_fun_def            ~> Inf_fun_def
   968     Meet_greatest           ~> Inf_greatest
   969     Meet_lower              ~> Inf_lower
   970     Meet_set_def            ~> Inf_set_def
   971 
   972     Sup_def                 ~> Sup_Inf
   973     Sup_bool_eq             ~> Sup_bool_def
   974     Sup_fun_eq              ~> Sup_fun_def
   975     Sup_set_eq              ~> Sup_set_def
   976 
   977     listsp_meetI            ~> listsp_infI
   978     listsp_meet_eq          ~> listsp_inf_eq
   979 
   980     meet_min                ~> inf_min
   981     join_max                ~> sup_max
   982 
   983 * Classes "order" and "linorder": facts "refl", "trans" and
   984 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   985 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   986 
   987 * Classes "order" and "linorder": 
   988 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   989 proofs changed.
   990 
   991 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   992 INCOMPATIBILITY.
   993 
   994 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   995 INCOMPATIBILITY.
   996 
   997 * Added syntactic class "size"; overloaded constant "size" now has
   998 type "'a::size ==> bool"
   999 
  1000 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
  1001 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
  1002 
  1003 * Added method "lexicographic_order" automatically synthesizes
  1004 termination relations as lexicographic combinations of size measures
  1005 -- 'function' package.
  1006 
  1007 * HOL/records: generalised field-update to take a function on the
  1008 field rather than the new value: r(|A := x|) is translated to A_update
  1009 (K x) r The K-combinator that is internally used is called K_record.
  1010 INCOMPATIBILITY: Usage of the plain update functions has to be
  1011 adapted.
  1012  
  1013 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
  1014 0 * x = 0, which are required for a semiring.  Richer structures do
  1015 not inherit from semiring_0 anymore, because this property is a
  1016 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
  1017 semiring_0, there is more to prove, but this is mostly trivial.
  1018 
  1019 * axclass "recpower" was generalized to arbitrary monoids, not just
  1020 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
  1021 commutativity or a semiring property, add the corresponding classes.
  1022 
  1023 * Unified locale partial_order with class definition (cf. theory
  1024 Orderings), added parameter ``less''.  INCOMPATIBILITY.
  1025 
  1026 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1027 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
  1028 Isar level, use abbreviations instead.
  1029 
  1030 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
  1031 rarely occuring name references (e.g. ``List.op mem.simps'') require
  1032 renaming (e.g. ``List.memberl.simps'').
  1033 
  1034 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
  1035 INCOMPATIBILITY.
  1036 
  1037 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
  1038 
  1039 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1040 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
  1041 significant changes for setting up numeral syntax for types:
  1042 
  1043   - new constants Numeral.pred and Numeral.succ instead
  1044       of former Numeral.bin_pred and Numeral.bin_succ.
  1045   - Use integer operations instead of bin_add, bin_mult and so on.
  1046   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1047   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1048 
  1049 See HOL/Integ/IntArith.thy for an example setup.
  1050 
  1051 * New top level command 'normal_form' computes the normal form of a
  1052 term that may contain free variables. For example ``normal_form
  1053 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
  1054 suitable for heavy-duty computations because the functions are
  1055 compiled to ML first.
  1056 
  1057 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1058 25 like -->); output depends on the "iff" print_mode, the default is
  1059 "A = B" (with priority 50).
  1060 
  1061 * Renamed constants in HOL.thy and Orderings.thy:
  1062     op +   ~> HOL.plus_class.plus
  1063     op -   ~> HOL.minus_class.minus
  1064     uminus ~> HOL.minus_class.uminus
  1065     abs    ~> HOL.abs_class.abs
  1066     op *   ~> HOL.times_class.times
  1067     op <   ~> HOL.ord_class.less
  1068     op <=  ~> HOL.ord_class.less_eq
  1069 
  1070 Adaptions may be required in the following cases:
  1071 
  1072 a) User-defined constants using any of the names "plus", "minus", "times",
  1073 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
  1074 may go wrong.
  1075 INCOMPATIBILITY: use more specific names.
  1076 
  1077 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1078 INCOMPATIBILITY: use more specific names.
  1079 
  1080 c) Permutative equations (e.g. "a + b = b + a")
  1081 Since the change of names also changes the order of terms, permutative
  1082 rewrite rules may get applied in a different order. Experience shows that
  1083 this is rarely the case (only two adaptions in the whole Isabelle
  1084 distribution).
  1085 INCOMPATIBILITY: rewrite proofs
  1086 
  1087 d) ML code directly refering to constant names
  1088 This in general only affects hand-written proof tactics, simprocs and so on.
  1089 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
  1090 of const_name ML antiquotations.
  1091 
  1092 * Relations less (<) and less_eq (<=) are also available on type bool.
  1093 Modified syntax to disallow nesting without explicit parentheses,
  1094 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
  1095 
  1096 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1097 
  1098 * Relation composition operator "op O" now has precedence 75 and binds
  1099 stronger than union and intersection. INCOMPATIBILITY.
  1100 
  1101 * The old set interval syntax "{m..n(}" (and relatives) has been
  1102 removed.  Use "{m..<n}" (and relatives) instead.
  1103 
  1104 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1105 "t = s" to False (by simproc "neq_simproc").  For backward
  1106 compatibility this can be disabled by ML "reset use_neq_simproc".
  1107 
  1108 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1109 simp.
  1110 
  1111 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1112 
  1113 * Theorem setsum_mult renamed to setsum_right_distrib.
  1114 
  1115 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1116 ``rule'' method.
  1117 
  1118 * Reimplemented methods ``sat'' and ``satx'', with several
  1119 improvements: goals no longer need to be stated as "<prems> ==>
  1120 False", equivalences (i.e. "=" on type bool) are handled, variable
  1121 names of the form "lit_<n>" are no longer reserved, significant
  1122 speedup.
  1123 
  1124 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1125 zChaff is still supported as well.
  1126 
  1127 * 'inductive' and 'datatype': provide projections of mutual rules,
  1128 bundled as foo_bar.inducts;
  1129 
  1130 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1131 Library.
  1132 
  1133 * Library: moved theory Accessible_Part to main HOL.
  1134 
  1135 * Library: added theory Coinductive_List of potentially infinite lists
  1136 as greatest fixed-point.
  1137 
  1138 * Library: added theory AssocList which implements (finite) maps as
  1139 association lists.
  1140 
  1141 * Added proof method ``evaluation'' for efficiently solving a goal
  1142 (i.e. a boolean expression) by compiling it to ML. The goal is
  1143 "proved" (via an oracle) if it evaluates to True.
  1144 
  1145 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1146 also when invoked by the simplifier.  This results in the simplifier
  1147 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1148 fast_arith_split_limit to 0 to obtain the old behavior.
  1149 
  1150 * Support for hex (0x20) and binary (0b1001) numerals.
  1151 
  1152 * New method: reify eqs (t), where eqs are equations for an
  1153 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1154 parameter, computes a term s::'b and a list xs::'a list and proves the
  1155 theorem I xs s = t. This is also known as reification or quoting. The
  1156 resulting theorem is applied to the subgoal to substitute t with I xs
  1157 s.  If t is omitted, the subgoal itself is reified.
  1158 
  1159 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1160 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1161 where f is supposed to be a computable function (in the sense of code
  1162 generattion). The method uses reify to compute s and xs as above then
  1163 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1164 r and finally gets the theorem t = r, which is again applied to the
  1165 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1166 
  1167 * Reflection: Automatic reification now handels binding, an example
  1168 is available in HOL/ex/ReflectionEx.thy
  1169 
  1170 
  1171 *** HOL-Algebra ***
  1172 
  1173 * Formalisation of ideals and the quotient construction over rings.
  1174 
  1175 * Order and lattice theory no longer based on records.
  1176 INCOMPATIBILITY.
  1177 
  1178 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1179 greatest_closed.  INCOMPATIBILITY.
  1180 
  1181 * Method algebra is now set up via an attribute.  For examples see
  1182 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1183 of algebraic structures.
  1184 
  1185 * Renamed theory CRing to Ring.
  1186 
  1187 
  1188 *** HOL-Complex ***
  1189 
  1190 * Theory Real: new method ferrack implements quantifier elimination
  1191 for linear arithmetic over the reals. The quantifier elimination
  1192 feature is used only for decision, for compatibility with arith. This
  1193 means a goal is either solved or left unchanged, no simplification.
  1194 
  1195 * Hyperreal: Functions root and sqrt are now defined on negative real
  1196 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1197 Nonnegativity side conditions have been removed from many lemmas, so
  1198 that more subgoals may now be solved by simplification; potential
  1199 INCOMPATIBILITY.
  1200 
  1201 * Real: New axiomatic classes formalize real normed vector spaces and
  1202 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1203 and norm :: 'a => real.
  1204 
  1205 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1206 from reals into other types. The overloaded constant Reals :: 'a set
  1207 is now defined as range of_real; potential INCOMPATIBILITY.
  1208 
  1209 * Real: ML code generation is supported now and hence also quickcheck.
  1210 Reals are implemented as arbitrary precision rationals.
  1211 
  1212 * Hyperreal: Several constants that previously worked only for the
  1213 reals have been generalized, so they now work over arbitrary vector
  1214 spaces. Type annotations may need to be added in some cases; potential
  1215 INCOMPATIBILITY.
  1216 
  1217   Infinitesimal  :: ('a::real_normed_vector) star set
  1218   HFinite        :: ('a::real_normed_vector) star set
  1219   HInfinite      :: ('a::real_normed_vector) star set
  1220   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1221   monad          :: ('a::real_normed_vector) star => 'a star set
  1222   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1223   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1224   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1225   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1226   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1227   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1228   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1229   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1230   sgn            :: 'a::real_normed_vector => 'a
  1231   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1232 
  1233 * Complex: Some complex-specific constants are now abbreviations for
  1234 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1235 hnorm.  Other constants have been entirely removed in favor of the
  1236 polymorphic versions (INCOMPATIBILITY):
  1237 
  1238   approx        <-- capprox
  1239   HFinite       <-- CFinite
  1240   HInfinite     <-- CInfinite
  1241   Infinitesimal <-- CInfinitesimal
  1242   monad         <-- cmonad
  1243   galaxy        <-- cgalaxy
  1244   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1245   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1246   (ns)deriv     <-- (ns)cderiv
  1247 
  1248 
  1249 *** ML ***
  1250 
  1251 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1252 
  1253 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1254 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1255 init only required for impure data.  INCOMPATIBILITY: empty really
  1256 need to be empty (no dependencies on theory content!)
  1257 
  1258 * ML within Isar: antiquotations allow to embed statically-checked
  1259 formal entities in the source, referring to the context available at
  1260 compile-time.  For example:
  1261 
  1262 ML {* @{typ "'a => 'b"} *}
  1263 ML {* @{term "%x. x"} *}
  1264 ML {* @{prop "x == y"} *}
  1265 ML {* @{ctyp "'a => 'b"} *}
  1266 ML {* @{cterm "%x. x"} *}
  1267 ML {* @{cprop "x == y"} *}
  1268 ML {* @{thm asm_rl} *}
  1269 ML {* @{thms asm_rl} *}
  1270 ML {* @{const_name c} *}
  1271 ML {* @{const_syntax c} *}
  1272 ML {* @{context} *}
  1273 ML {* @{theory} *}
  1274 ML {* @{theory Pure} *}
  1275 ML {* @{simpset} *}
  1276 ML {* @{claset} *}
  1277 ML {* @{clasimpset} *}
  1278 
  1279 The same works for sources being ``used'' within an Isar context.
  1280 
  1281 * ML in Isar: improved error reporting; extra verbosity with
  1282 Toplevel.debug enabled.
  1283 
  1284 * Pure/library:
  1285 
  1286   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1287   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1288 
  1289 The semantics of "burrow" is: "take a function with *simulatanously*
  1290 transforms a list of value, and apply it *simulatanously* to a list of
  1291 list of values of the appropriate type". Compare this with "map" which
  1292 would *not* apply its argument function simulatanously but in
  1293 sequence; "fold_burrow" has an additional context.
  1294 
  1295 * Pure/library: functions map2 and fold2 with curried syntax for
  1296 simultanous mapping and folding:
  1297 
  1298     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1299     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1300 
  1301 * Pure/library: indexed lists - some functions in the Isabelle library
  1302 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1303 given more convenient names and signatures reminiscent of similar
  1304 functions for alists, tables, etc:
  1305 
  1306   val nth: 'a list -> int -> 'a 
  1307   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1308   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1309 
  1310 Note that fold_index starts counting at index 0, not 1 like foldln
  1311 used to.
  1312 
  1313 * Pure/library: added general ``divide_and_conquer'' combinator on
  1314 lists.
  1315 
  1316 * Pure/General/table.ML: the join operations now works via exceptions
  1317 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1318 admits slightly more efficient complex applications.
  1319 
  1320 * Pure: datatype Context.generic joins theory/Proof.context and
  1321 provides some facilities for code that works in either kind of
  1322 context, notably GenericDataFun for uniform theory and proof data.
  1323 
  1324 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1325 use Context.generic instead of just theory.
  1326 
  1327 * Pure: simplified internal attribute type, which is now always
  1328 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1329 vs. local (Proof.context) attributes have been discontinued, while
  1330 minimizing code duplication.  Thm.rule_attribute and
  1331 Thm.declaration_attribute build canonical attributes; see also
  1332 structure Context for further operations on Context.generic, notably
  1333 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1334 declarations and definitions.
  1335 
  1336 * Pure/kernel: consts certification ignores sort constraints given in
  1337 signature declarations.  (This information is not relevant to the
  1338 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1339 potential INCOMPATIBILITY.
  1340 
  1341 * Pure: axiomatic type classes are now purely definitional, with
  1342 explicit proofs of class axioms and super class relations performed
  1343 internally.  See Pure/axclass.ML for the main internal interfaces --
  1344 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1345 AxClass.axiomatize_class/classrel/arity supercede
  1346 Sign.add_classes/classrel/arities.
  1347 
  1348 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1349 global/local versions on theory vs. Proof.context have been
  1350 discontinued; Attrib.syntax and Method.syntax have been adapted
  1351 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1352 attributes, methods, etc.
  1353 
  1354 * Pure: several functions of signature "... -> theory -> theory * ..."
  1355 have been reoriented to "... -> theory -> ... * theory" in order to
  1356 allow natural usage in combination with the ||>, ||>>, |-> and
  1357 fold_map combinators.
  1358 
  1359 * Pure: official theorem names (closed derivations) and additional
  1360 comments (tags) are now strictly separate.  Name hints -- which are
  1361 maintained as tags -- may be attached any time without affecting the
  1362 derivation.
  1363 
  1364 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1365 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1366 achieve the old behaviour.
  1367 
  1368 * Pure: the "Goal" constant is now called "prop", supporting a
  1369 slightly more general idea of ``protecting'' meta-level rule
  1370 statements.
  1371 
  1372 * Pure: Logic.(un)varify only works in a global context, which is now
  1373 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1374 Logic.legacy_(un)varify as temporary workaround.
  1375 
  1376 * Pure: structure Name provides scalable operations for generating
  1377 internal variable names, notably Name.variants etc.  This replaces
  1378 some popular functions from term.ML:
  1379 
  1380   Term.variant		->  Name.variant
  1381   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1382   Term.invent_names	->  Name.invent_list
  1383 
  1384 Note that low-level renaming rarely occurs in new code -- operations
  1385 from structure Variable are used instead (see below).
  1386 
  1387 * Pure: structure Variable provides fundamental operations for proper
  1388 treatment of fixed/schematic variables in a context.  For example,
  1389 Variable.import introduces fixes for schematics of given facts and
  1390 Variable.export reverses the effect (up to renaming) -- this replaces
  1391 various freeze_thaw operations.
  1392 
  1393 * Pure: structure Goal provides simple interfaces for
  1394 init/conclude/finish and tactical prove operations (replacing former
  1395 Tactic.prove).  Goal.prove is the canonical way to prove results
  1396 within a given context; Goal.prove_global is a degraded version for
  1397 theory level goals, including a global Drule.standard.  Note that
  1398 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1399 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1400 in a locale context).
  1401 
  1402 * Isar: simplified treatment of user-level errors, using exception
  1403 ERROR of string uniformly.  Function error now merely raises ERROR,
  1404 without any side effect on output channels.  The Isar toplevel takes
  1405 care of proper display of ERROR exceptions.  ML code may use plain
  1406 handle/can/try; cat_error may be used to concatenate errors like this:
  1407 
  1408   ... handle ERROR msg => cat_error msg "..."
  1409 
  1410 Toplevel ML code (run directly or through the Isar toplevel) may be
  1411 embedded into the Isar toplevel with exception display/debug like
  1412 this:
  1413 
  1414   Isar.toplevel (fn () => ...)
  1415 
  1416 INCOMPATIBILITY, removed special transform_error facilities, removed
  1417 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1418 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1419 -- use plain ERROR instead.
  1420 
  1421 * Isar: theory setup now has type (theory -> theory), instead of a
  1422 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1423 
  1424 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1425 subject to ProofContext.debug/verbose flags.
  1426 
  1427 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1428 theory before entering a proof state.  Transactions now always see a
  1429 quasi-functional intermediate checkpoint, both in interactive and
  1430 batch mode.
  1431 
  1432 * Simplifier: the simpset of a running simplification process now
  1433 contains a proof context (cf. Simplifier.the_context), which is the
  1434 very context that the initial simpset has been retrieved from (by
  1435 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1436 (solver, looper etc.) may depend on arbitrary proof data.
  1437 
  1438 * Simplifier.inherit_context inherits the proof context (plus the
  1439 local bounds) of the current simplification process; any simproc
  1440 etc. that calls the Simplifier recursively should do this!  Removed
  1441 former Simplifier.inherit_bounds, which is already included here --
  1442 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1443 specify an explicit context using Simplifier.context/theory_context.
  1444 
  1445 * Simplifier/Classical Reasoner: more abstract interfaces
  1446 change_simpset/claset for modifying the simpset/claset reference of a
  1447 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1448 INCOMPATIBILITY.
  1449 
  1450 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1451 "Trueprop" etc.
  1452 
  1453 
  1454 *** System ***
  1455 
  1456 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1457 locations -- now includes the Isabelle version identifier as well.
  1458 This simplifies use of multiple Isabelle installations.
  1459 
  1460 * isabelle-process: option -S (secure mode) disables some critical
  1461 operations, notably runtime compilation and evaluation of ML source
  1462 code.
  1463 
  1464 * Experimental support for multithreading, using Poly/ML 5.1 (internal
  1465 version from CVS). The theory loader exploits parallelism when
  1466 processing independent theories, following the header specifications.
  1467 The maximum number of worker threads is specified via usedir option -M
  1468 or the "max-threads" setting in Proof General.  User-code needs to
  1469 observe certain guidelines for thread-safe programming, see appendix A
  1470 in the Isar Implementation manual.
  1471 
  1472 
  1473 New in Isabelle2005 (October 2005)
  1474 ----------------------------------
  1475 
  1476 *** General ***
  1477 
  1478 * Theory headers: the new header syntax for Isar theories is
  1479 
  1480   theory <name>
  1481   imports <theory1> ... <theoryN>
  1482   uses <file1> ... <fileM>
  1483   begin
  1484 
  1485 where the 'uses' part is optional.  The previous syntax
  1486 
  1487   theory <name> = <theory1> + ... + <theoryN>:
  1488 
  1489 will disappear in the next release.  Use isatool fixheaders to convert
  1490 existing theory files.  Note that there is no change in ancient
  1491 non-Isar theories now, but these will disappear soon.
  1492 
  1493 * Theory loader: parent theories can now also be referred to via
  1494 relative and absolute paths.
  1495 
  1496 * Command 'find_theorems' searches for a list of criteria instead of a
  1497 list of constants. Known criteria are: intro, elim, dest, name:string,
  1498 simp:term, and any term. Criteria can be preceded by '-' to select
  1499 theorems that do not match. Intro, elim, dest select theorems that
  1500 match the current goal, name:s selects theorems whose fully qualified
  1501 name contain s, and simp:term selects all simplification rules whose
  1502 lhs match term.  Any other term is interpreted as pattern and selects
  1503 all theorems matching the pattern. Available in ProofGeneral under
  1504 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1505 
  1506   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1507 
  1508 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1509 matching the current goal as introduction rule and not having "HOL."
  1510 in their name (i.e. not being defined in theory HOL).
  1511 
  1512 * Command 'thms_containing' has been discontinued in favour of
  1513 'find_theorems'; INCOMPATIBILITY.
  1514 
  1515 * Communication with Proof General is now 8bit clean, which means that
  1516 Unicode text in UTF-8 encoding may be used within theory texts (both
  1517 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1518 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1519 
  1520   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1521   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1522 
  1523 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1524 Classical Reasoner.  Typical big applications run around 2 times
  1525 faster.
  1526 
  1527 
  1528 *** Document preparation ***
  1529 
  1530 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1531 of raw sources.  Only those symbols that do not require additional
  1532 LaTeX packages (depending on comments in isabellesym.sty) are
  1533 displayed properly, everything else is left verbatim.  isatool display
  1534 and isatool print are used as front ends (these are subject to the
  1535 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1536 
  1537 * Command tags control specific markup of certain regions of text,
  1538 notably folding and hiding.  Predefined tags include "theory" (for
  1539 theory begin and end), "proof" for proof commands, and "ML" for
  1540 commands involving ML code; the additional tags "visible" and
  1541 "invisible" are unused by default.  Users may give explicit tag
  1542 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1543 interpretation of tags is determined by the LaTeX job during document
  1544 preparation: see option -V of isatool usedir, or options -n and -t of
  1545 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1546 \isadroptag.
  1547 
  1548 Several document versions may be produced at the same time via isatool
  1549 usedir (the generated index.html will link all of them).  Typical
  1550 specifications include ''-V document=theory,proof,ML'' to present
  1551 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1552 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1553 these parts without any formal replacement text.  The Isabelle site
  1554 default settings produce ''document'' and ''outline'' versions as
  1555 specified above.
  1556 
  1557 * Several new antiquotations:
  1558 
  1559   @{term_type term} prints a term with its type annotated;
  1560 
  1561   @{typeof term} prints the type of a term;
  1562 
  1563   @{const const} is the same as @{term const}, but checks that the
  1564   argument is a known logical constant;
  1565 
  1566   @{term_style style term} and @{thm_style style thm} print a term or
  1567   theorem applying a "style" to it
  1568 
  1569   @{ML text}
  1570 
  1571 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1572 definitions, equations, inequations etc., 'concl' printing only the
  1573 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1574 to print the specified premise.  TermStyle.add_style provides an ML
  1575 interface for introducing further styles.  See also the "LaTeX Sugar"
  1576 document practical applications.  The ML antiquotation prints
  1577 type-checked ML expressions verbatim.
  1578 
  1579 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1580 and 'text' support optional locale specification '(in loc)', which
  1581 specifies the default context for interpreting antiquotations.  For
  1582 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1583 
  1584 * Option 'locale=NAME' of antiquotations specifies an alternative
  1585 context interpreting the subsequent argument.  For example: @{thm
  1586 [locale=lattice] inf_assoc}.
  1587 
  1588 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1589 a proof context.
  1590 
  1591 * Proper output of antiquotations for theory commands involving a
  1592 proof context (such as 'locale' or 'theorem (in loc) ...').
  1593 
  1594 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1595 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1596 
  1597 * isatool usedir: new option -C (default true) controls whether option
  1598 -D should include a copy of the original document directory; -C false
  1599 prevents unwanted effects such as copying of administrative CVS data.
  1600 
  1601 
  1602 *** Pure ***
  1603 
  1604 * Considerably improved version of 'constdefs' command.  Now performs
  1605 automatic type-inference of declared constants; additional support for
  1606 local structure declarations (cf. locales and HOL records), see also
  1607 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1608 sequential dependencies of definitions within a single 'constdefs'
  1609 section; moreover, the declared name needs to be an identifier.  If
  1610 all fails, consider to fall back on 'consts' and 'defs' separately.
  1611 
  1612 * Improved indexed syntax and implicit structures.  First of all,
  1613 indexed syntax provides a notational device for subscripted
  1614 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1615 expressions.  Secondly, in a local context with structure
  1616 declarations, number indexes \<^sub>n or the empty index (default
  1617 number 1) refer to a certain fixed variable implicitly; option
  1618 show_structs controls printing of implicit structures.  Typical
  1619 applications of these concepts involve record types and locales.
  1620 
  1621 * New command 'no_syntax' removes grammar declarations (and
  1622 translations) resulting from the given syntax specification, which is
  1623 interpreted in the same manner as for the 'syntax' command.
  1624 
  1625 * 'Advanced' translation functions (parse_translation etc.) may depend
  1626 on the signature of the theory context being presently used for
  1627 parsing/printing, see also isar-ref manual.
  1628 
  1629 * Improved 'oracle' command provides a type-safe interface to turn an
  1630 ML expression of type theory -> T -> term into a primitive rule of
  1631 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1632 is already included here); see also FOL/ex/IffExample.thy;
  1633 INCOMPATIBILITY.
  1634 
  1635 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1636 before); "cI" is no longer bound, use "c.intro" instead.
  1637 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1638 axclasses vs. locales.
  1639 
  1640 * Improved internal renaming of symbolic identifiers -- attach primes
  1641 instead of base 26 numbers.
  1642 
  1643 * New flag show_question_marks controls printing of leading question
  1644 marks in schematic variable names.
  1645 
  1646 * In schematic variable names, *any* symbol following \<^isub> or
  1647 \<^isup> is now treated as part of the base name.  For example, the
  1648 following works without printing of awkward ".0" indexes:
  1649 
  1650   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1651     by simp
  1652 
  1653 * Inner syntax includes (*(*nested*) comments*).
  1654 
  1655 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1656 annotations as "(00...)".
  1657 
  1658 * Clear separation of logical types and nonterminals, where the latter
  1659 may only occur in 'syntax' specifications or type abbreviations.
  1660 Before that distinction was only partially implemented via type class
  1661 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1662 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1663 exotic syntax specifications may require further adaption
  1664 (e.g. Cube/Cube.thy).
  1665 
  1666 * Removed obsolete type class "logic", use the top sort {} instead.
  1667 Note that non-logical types should be declared as 'nonterminals'
  1668 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1669 specifications.
  1670 
  1671 * Attributes 'induct' and 'cases': type or set names may now be
  1672 locally fixed variables as well.
  1673 
  1674 * Simplifier: can now control the depth to which conditional rewriting
  1675 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1676 Limit.
  1677 
  1678 * Simplifier: simplification procedures may now take the current
  1679 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1680 interface), which is very useful for calling the Simplifier
  1681 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1682 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1683 low-level mk_simproc no longer applies Logic.varify internally, to
  1684 allow for use in a context of fixed variables.
  1685 
  1686 * thin_tac now works even if the assumption being deleted contains !!
  1687 or ==>.  More generally, erule now works even if the major premise of
  1688 the elimination rule contains !! or ==>.
  1689 
  1690 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1691 
  1692 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1693 from Pure, which contains all common declarations already.  Both
  1694 theories are defined via plain Isabelle/Isar .thy files.
  1695 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1696 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1697 use isatool fixcpure to adapt your theory and ML sources.
  1698 
  1699 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1700 selections of theorems in named facts via index ranges.
  1701 
  1702 * 'print_theorems': in theory mode, really print the difference
  1703 wrt. the last state (works for interactive theory development only),
  1704 in proof mode print all local facts (cf. 'print_facts');
  1705 
  1706 * 'hide': option '(open)' hides only base names.
  1707 
  1708 * More efficient treatment of intermediate checkpoints in interactive
  1709 theory development.
  1710 
  1711 * Code generator is now invoked via code_module (incremental code
  1712 generation) and code_library (modular code generation, ML structures
  1713 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1714 must be quoted when used as identifiers.
  1715 
  1716 * New 'value' command for reading, evaluating and printing terms using
  1717 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1718 quoted when used as identifier.
  1719 
  1720 
  1721 *** Locales ***
  1722 
  1723 * New commands for the interpretation of locale expressions in
  1724 theories (1), locales (2) and proof contexts (3).  These generate
  1725 proof obligations from the expression specification.  After the
  1726 obligations have been discharged, theorems of the expression are added
  1727 to the theory, target locale or proof context.  The synopsis of the
  1728 commands is a follows:
  1729 
  1730   (1) interpretation expr inst
  1731   (2) interpretation target < expr
  1732   (3) interpret expr inst
  1733 
  1734 Interpretation in theories and proof contexts require a parameter
  1735 instantiation of terms from the current context.  This is applied to
  1736 specifications and theorems of the interpreted expression.
  1737 Interpretation in locales only permits parameter renaming through the
  1738 locale expression.  Interpretation is smart in that interpretations
  1739 that are active already do not occur in proof obligations, neither are
  1740 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1741 inspect active interpretations of a particular locale.  For details,
  1742 see the Isar Reference manual.  Examples can be found in
  1743 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1744 
  1745 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1746 'interpret' instead.
  1747 
  1748 * New context element 'constrains' for adding type constraints to
  1749 parameters.
  1750 
  1751 * Context expressions: renaming of parameters with syntax
  1752 redeclaration.
  1753 
  1754 * Locale declaration: 'includes' disallowed.
  1755 
  1756 * Proper static binding of attribute syntax -- i.e. types / terms /
  1757 facts mentioned as arguments are always those of the locale definition
  1758 context, independently of the context of later invocations.  Moreover,
  1759 locale operations (renaming and type / term instantiation) are applied
  1760 to attribute arguments as expected.
  1761 
  1762 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1763 actual attributes; rare situations may require Attrib.attribute to
  1764 embed those attributes into Attrib.src that lack concrete syntax.
  1765 Attribute implementations need to cooperate properly with the static
  1766 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1767 Attrib.XXX_thm etc. already do the right thing without further
  1768 intervention.  Only unusual applications -- such as "where" or "of"
  1769 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1770 on the context and the facts involved -- may have to assign parsed
  1771 values to argument tokens explicitly.
  1772 
  1773 * Changed parameter management in theorem generation for long goal
  1774 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1775 theorem statement in rare situations.
  1776 
  1777 * Locale inspection command 'print_locale' omits notes elements.  Use
  1778 'print_locale!' to have them included in the output.
  1779 
  1780 
  1781 *** Provers ***
  1782 
  1783 * Provers/hypsubst.ML: improved version of the subst method, for
  1784 single-step rewriting: it now works in bound variable contexts. New is
  1785 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1786 rewrite a different subterm than the original subst method, which is
  1787 still available as 'simplesubst'.
  1788 
  1789 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1790 and quasi orders.
  1791 
  1792 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1793 reflexive-transitive closure of relations.
  1794 
  1795 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1796 limit (previously hard-coded with a value of 20) user-definable.
  1797 
  1798 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1799 is peformed already.  Object-logics merely need to finish their
  1800 initial simpset configuration as before.  INCOMPATIBILITY.
  1801 
  1802 
  1803 *** HOL ***
  1804 
  1805 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1806 
  1807   syntax (epsilon)
  1808     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1809 
  1810 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1811 and x-symbol; use option '-m epsilon' to get it actually printed.
  1812 Moreover, the mathematically important symbolic identifier \<epsilon>
  1813 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1814 
  1815 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1816 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1817 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1818 support corresponding Isar calculations.
  1819 
  1820 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1821 instead of ":".
  1822 
  1823 * theory SetInterval: changed the syntax for open intervals:
  1824 
  1825   Old       New
  1826   {..n(}    {..<n}
  1827   {)n..}    {n<..}
  1828   {m..n(}   {m..<n}
  1829   {)m..n}   {m<..n}
  1830   {)m..n(}  {m<..<n}
  1831 
  1832 The old syntax is still supported but will disappear in the next
  1833 release.  For conversion use the following Emacs search and replace
  1834 patterns (these are not perfect but work quite well):
  1835 
  1836   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1837   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1838 
  1839 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1840 equalities in commutative rings; method 'algebra' provides a generic
  1841 interface.
  1842 
  1843 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1844 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1845 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1846 be a tuple pattern.
  1847 
  1848 Some new syntax forms are available:
  1849 
  1850   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1851   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1852   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1853   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1854 
  1855 The latter form "\<Sum>x < k. e" used to be based on a separate
  1856 function "Summation", which has been discontinued.
  1857 
  1858 * theory Finite_Set: in structured induction proofs, the insert case
  1859 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1860 (insert F x)'.
  1861 
  1862 * The 'refute' command has been extended to support a much larger
  1863 fragment of HOL, including axiomatic type classes, constdefs and
  1864 typedefs, inductive datatypes and recursion.
  1865 
  1866 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1867 Requires zChaff with proof generation to be installed.  See
  1868 HOL/ex/SAT_Examples.thy for examples.
  1869 
  1870 * Datatype induction via method 'induct' now preserves the name of the
  1871 induction variable. For example, when proving P(xs::'a list) by
  1872 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1873 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1874 in unstructured proof scripts.
  1875 
  1876 * Reworked implementation of records.  Improved scalability for
  1877 records with many fields, avoiding performance problems for type
  1878 inference. Records are no longer composed of nested field types, but
  1879 of nested extension types. Therefore the record type only grows linear
  1880 in the number of extensions and not in the number of fields.  The
  1881 top-level (users) view on records is preserved.  Potential
  1882 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1883 old record representation. The type generated for a record is called
  1884 <record_name>_ext_type.
  1885 
  1886 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1887 proofs triggered by a record definition or a simproc (if
  1888 quick_and_dirty is enabled).  Definitions of large records can take
  1889 quite long.
  1890 
  1891 New simproc record_upd_simproc for simplification of multiple record
  1892 updates enabled by default.  Moreover, trivial updates are also
  1893 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1894 occasionally, since simplification is more powerful by default.
  1895 
  1896 * typedef: proper support for polymorphic sets, which contain extra
  1897 type-variables in the term.
  1898 
  1899 * Simplifier: automatically reasons about transitivity chains
  1900 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1901 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1902 old proofs break occasionally as simplification may now solve more
  1903 goals than previously.
  1904 
  1905 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1906 present.  Works for all partial orders (class "order"), in particular
  1907 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1908 just like y <= x.
  1909 
  1910 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1911 bound variable or a constant then the let is unfolded.  Otherwise
  1912 first a is simplified to b, and then f b is simplified to g. If
  1913 possible we abstract b from g arriving at "let x = b in h x",
  1914 otherwise we unfold the let and arrive at g.  The simproc can be
  1915 enabled/disabled by the reference use_let_simproc.  Potential
  1916 INCOMPATIBILITY since simplification is more powerful by default.
  1917 
  1918 * Classical reasoning: the meson method now accepts theorems as arguments.
  1919 
  1920 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1921 jobs to provide advice on the provability of subgoals.
  1922 
  1923 * Theory OrderedGroup and Ring_and_Field: various additions and
  1924 improvements to faciliate calculations involving equalities and
  1925 inequalities.
  1926 
  1927 The following theorems have been eliminated or modified
  1928 (INCOMPATIBILITY):
  1929 
  1930   abs_eq             now named abs_of_nonneg
  1931   abs_of_ge_0        now named abs_of_nonneg
  1932   abs_minus_eq       now named abs_of_nonpos
  1933   imp_abs_id         now named abs_of_nonneg
  1934   imp_abs_neg_id     now named abs_of_nonpos
  1935   mult_pos           now named mult_pos_pos
  1936   mult_pos_le        now named mult_nonneg_nonneg
  1937   mult_pos_neg_le    now named mult_nonneg_nonpos
  1938   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1939   mult_neg           now named mult_neg_neg
  1940   mult_neg_le        now named mult_nonpos_nonpos
  1941 
  1942 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1943      
  1944      zero_le_square
  1945      not_square_less_zero 
  1946 
  1947   The following lemmas have been deleted from Real/RealPow:
  1948   
  1949      realpow_zero_zero
  1950      realpow_two
  1951      realpow_less
  1952      zero_le_power
  1953      realpow_two_le
  1954      abs_realpow_two
  1955      realpow_two_abs     
  1956 
  1957 * Theory Parity: added rules for simplifying exponents.
  1958 
  1959 * Theory List:
  1960 
  1961 The following theorems have been eliminated or modified
  1962 (INCOMPATIBILITY):
  1963 
  1964   list_all_Nil       now named list_all.simps(1)
  1965   list_all_Cons      now named list_all.simps(2)
  1966   list_all_conv      now named list_all_iff
  1967   set_mem_eq         now named mem_iff
  1968 
  1969 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1970 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1971 
  1972 
  1973 *** HOL-Complex ***
  1974 
  1975 * Theory RealDef: better support for embedding natural numbers and
  1976 integers in the reals.
  1977 
  1978 The following theorems have been eliminated or modified
  1979 (INCOMPATIBILITY):
  1980 
  1981   exp_ge_add_one_self  now requires no hypotheses
  1982   real_of_int_add      reversed direction of equality (use [symmetric])
  1983   real_of_int_minus    reversed direction of equality (use [symmetric])
  1984   real_of_int_diff     reversed direction of equality (use [symmetric])
  1985   real_of_int_mult     reversed direction of equality (use [symmetric])
  1986 
  1987 * Theory RComplete: expanded support for floor and ceiling functions.
  1988 
  1989 * Theory Ln is new, with properties of the natural logarithm
  1990 
  1991 * Hyperreal: There is a new type constructor "star" for making
  1992 nonstandard types.  The old type names are now type synonyms:
  1993 
  1994   hypreal = real star
  1995   hypnat = nat star
  1996   hcomplex = complex star
  1997 
  1998 * Hyperreal: Many groups of similarly-defined constants have been
  1999 replaced by polymorphic versions (INCOMPATIBILITY):
  2000 
  2001   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2002 
  2003   starset      <-- starsetNat, starsetC
  2004   *s*          <-- *sNat*, *sc*
  2005   starset_n    <-- starsetNat_n, starsetC_n
  2006   *sn*         <-- *sNatn*, *scn*
  2007   InternalSets <-- InternalNatSets, InternalCSets
  2008 
  2009   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2010   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2011   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2012   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2013   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2014 
  2015 * Hyperreal: Many type-specific theorems have been removed in favor of
  2016 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2017 
  2018   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2019   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2020   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2021   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2022   right_minus <-- hypreal_add_minus
  2023   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2024   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2025   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2026   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2027   mult_1_right <-- hcomplex_mult_one_right
  2028   mult_zero_left <-- hcomplex_mult_zero_left
  2029   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2030   right_distrib <-- hypnat_add_mult_distrib2
  2031   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2032   right_inverse <-- hypreal_mult_inverse
  2033   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2034   order_refl <-- {hypreal,hypnat}_le_refl
  2035   order_trans <-- {hypreal,hypnat}_le_trans
  2036   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2037   order_less_le <-- {hypreal,hypnat}_less_le
  2038   linorder_linear <-- {hypreal,hypnat}_le_linear
  2039   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2040   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2041   add_nonneg_nonneg <-- hypreal_le_add_order
  2042 
  2043 * Hyperreal: Separate theorems having to do with type-specific
  2044 versions of constants have been merged into theorems that apply to the
  2045 new polymorphic constants (INCOMPATIBILITY):
  2046 
  2047   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2048   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2049   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2050   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2051   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2052   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2053   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2054   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2055   STAR_diff <-- {STAR,STARC}_diff
  2056   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2057     STARC_hcomplex_of_complex}_image_subset
  2058   starset_n_Un <-- starset{Nat,C}_n_Un
  2059   starset_n_Int <-- starset{Nat,C}_n_Int
  2060   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2061   starset_n_diff <-- starset{Nat,C}_n_diff
  2062   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2063   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2064   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2065   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2066   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2067   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2068   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2069   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2070   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2071   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2072   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2073   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2074   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2075   starfun_diff <-- starfun{C,RC,CR}_diff
  2076   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2077   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2078   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2079   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2080   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2081   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2082   starfun_Id <-- starfunC_Id
  2083   starfun_approx <-- starfun{Nat,CR}_approx
  2084   starfun_capprox <-- starfun{C,RC}_capprox
  2085   starfun_abs <-- starfunNat_rabs
  2086   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2087   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2088   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2089   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2090   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2091   starfun_add_approx <-- starfunCR_add_approx
  2092   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2093   starfun_divide <-- starfun{C,CR,RC}_divide
  2094   starfun_n <-- starfun{Nat,C}_n
  2095   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2096   starfun_n_add <-- starfun{Nat,C}_n_add
  2097   starfun_n_add_minus <-- starfunNat_n_add_minus
  2098   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2099   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2100   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2101 
  2102   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2103   star_n_minus <-- {hypreal,hcomplex}_minus
  2104   star_n_diff <-- {hypreal,hcomplex}_diff
  2105   star_n_mult <-- {hypreal,hcomplex}_mult
  2106   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2107   star_n_le <-- {hypreal,hypnat}_le
  2108   star_n_less <-- {hypreal,hypnat}_less
  2109   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2110   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2111   star_n_abs <-- hypreal_hrabs
  2112   star_n_divide <-- hcomplex_divide
  2113 
  2114   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2115   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2116   star_of_diff <-- hypreal_of_real_diff
  2117   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2118   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2119   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2120   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2121   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2122   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2123   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2124   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2125   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2126   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2127   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2128   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2129   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2130   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2131   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2132   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2133   star_of_power <-- hypreal_of_real_power
  2134   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2135 
  2136 * Hyperreal: new method "transfer" that implements the transfer
  2137 principle of nonstandard analysis. With a subgoal that mentions
  2138 nonstandard types like "'a star", the command "apply transfer"
  2139 replaces it with an equivalent one that mentions only standard types.
  2140 To be successful, all free variables must have standard types; non-
  2141 standard variables must have explicit universal quantifiers.
  2142 
  2143 * Hyperreal: A theory of Taylor series.
  2144 
  2145 
  2146 *** HOLCF ***
  2147 
  2148 * Discontinued special version of 'constdefs' (which used to support
  2149 continuous functions) in favor of the general Pure one with full
  2150 type-inference.
  2151 
  2152 * New simplification procedure for solving continuity conditions; it
  2153 is much faster on terms with many nested lambda abstractions (cubic
  2154 instead of exponential time).
  2155 
  2156 * New syntax for domain package: selector names are now optional.
  2157 Parentheses should be omitted unless argument is lazy, for example:
  2158 
  2159   domain 'a stream = cons "'a" (lazy "'a stream")
  2160 
  2161 * New command 'fixrec' for defining recursive functions with pattern
  2162 matching; defining multiple functions with mutual recursion is also
  2163 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2164 sinr, or any data constructor defined by the domain package. The given
  2165 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2166 syntax and examples.
  2167 
  2168 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2169 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2170 but the proof obligation additionally includes an admissibility
  2171 requirement. The packages generate instances of class cpo or pcpo,
  2172 with continuity and strictness theorems for Rep and Abs.
  2173 
  2174 * HOLCF: Many theorems have been renamed according to a more standard naming
  2175 scheme (INCOMPATIBILITY):
  2176 
  2177   foo_inject:  "foo$x = foo$y ==> x = y"
  2178   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2179   foo_less:    "(foo$x << foo$y) = (x << y)"
  2180   foo_strict:  "foo$UU = UU"
  2181   foo_defined: "... ==> foo$x ~= UU"
  2182   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2183 
  2184 
  2185 *** ZF ***
  2186 
  2187 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2188 including the First Isomorphism Theorem (on quotienting by the kernel
  2189 of a homomorphism).
  2190 
  2191 * ZF/Simplifier: install second copy of type solver that actually
  2192 makes use of TC rules declared to Isar proof contexts (or locales);
  2193 the old version is still required for ML proof scripts.
  2194 
  2195 
  2196 *** Cube ***
  2197 
  2198 * Converted to Isar theory format; use locales instead of axiomatic
  2199 theories.
  2200 
  2201 
  2202 *** ML ***
  2203 
  2204 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2205 for ||>, ||>>, |>>,
  2206 
  2207 * Pure/library.ML no longer defines its own option datatype, but uses
  2208 that of the SML basis, which has constructors NONE and SOME instead of
  2209 None and Some, as well as exception Option.Option instead of OPTION.
  2210 The functions the, if_none, is_some, is_none have been adapted
  2211 accordingly, while Option.map replaces apsome.
  2212 
  2213 * Pure/library.ML: the exception LIST has been given up in favour of
  2214 the standard exceptions Empty and Subscript, as well as
  2215 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2216 superceded by the standard hd and tl functions etc.
  2217 
  2218 A number of basic list functions are no longer exported to the ML
  2219 toplevel, as they are variants of predefined functions.  The following
  2220 suggests how one can translate existing code:
  2221 
  2222     rev_append xs ys = List.revAppend (xs, ys)
  2223     nth_elem (i, xs) = List.nth (xs, i)
  2224     last_elem xs = List.last xs
  2225     flat xss = List.concat xss
  2226     seq fs = List.app fs
  2227     partition P xs = List.partition P xs
  2228     mapfilter f xs = List.mapPartial f xs
  2229 
  2230 * Pure/library.ML: several combinators for linear functional
  2231 transformations, notably reverse application and composition:
  2232 
  2233   x |> f                f #> g
  2234   (x, y) |-> f          f #-> g
  2235 
  2236 * Pure/library.ML: introduced/changed precedence of infix operators:
  2237 
  2238   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2239   infix 2 ?;
  2240   infix 3 o oo ooo oooo;
  2241   infix 4 ~~ upto downto;
  2242 
  2243 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2244 infix operators.
  2245 
  2246 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2247 fold_map support linear functional transformations and nesting.  For
  2248 example:
  2249 
  2250   fold f [x1, ..., xN] y =
  2251     y |> f x1 |> ... |> f xN
  2252 
  2253   (fold o fold) f [xs1, ..., xsN] y =
  2254     y |> fold f xs1 |> ... |> fold f xsN
  2255 
  2256   fold f [x1, ..., xN] =
  2257     f x1 #> ... #> f xN
  2258 
  2259   (fold o fold) f [xs1, ..., xsN] =
  2260     fold f xs1 #> ... #> fold f xsN
  2261 
  2262 * Pure/library.ML: the following selectors on type 'a option are
  2263 available:
  2264 
  2265   the:               'a option -> 'a  (*partial*)
  2266   these:             'a option -> 'a  where 'a = 'b list
  2267   the_default: 'a -> 'a option -> 'a
  2268   the_list:          'a option -> 'a list
  2269 
  2270 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2271 basic operations for association lists, following natural argument
  2272 order; moreover the explicit equality predicate passed here avoids
  2273 potentially expensive polymorphic runtime equality checks.
  2274 The old functions may be expressed as follows:
  2275 
  2276   assoc = uncurry (AList.lookup (op =))
  2277   assocs = these oo AList.lookup (op =)
  2278   overwrite = uncurry (AList.update (op =)) o swap
  2279 
  2280 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2281 
  2282   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2283   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2284 
  2285 replacing make_keylist and keyfilter (occassionally used)
  2286 Naive rewrites:
  2287 
  2288   make_keylist = AList.make
  2289   keyfilter = AList.find (op =)
  2290 
  2291 * eq_fst and eq_snd now take explicit equality parameter, thus
  2292   avoiding eqtypes. Naive rewrites:
  2293 
  2294     eq_fst = eq_fst (op =)
  2295     eq_snd = eq_snd (op =)
  2296 
  2297 * Removed deprecated apl and apr (rarely used).
  2298   Naive rewrites:
  2299 
  2300     apl (n, op) =>>= curry op n
  2301     apr (op, m) =>>= fn n => op (n, m)
  2302 
  2303 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2304 provides a reasonably efficient light-weight implementation of sets as
  2305 lists.
  2306 
  2307 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2308 few new operations; existing lookup and update are now curried to
  2309 follow natural argument order (for use with fold etc.);
  2310 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2311 
  2312 * Pure/General: output via the Isabelle channels of
  2313 writeln/warning/error etc. is now passed through Output.output, with a
  2314 hook for arbitrary transformations depending on the print_mode
  2315 (cf. Output.add_mode -- the first active mode that provides a output
  2316 function wins).  Already formatted output may be embedded into further
  2317 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2318 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2319 accommodate easy composition of diagnostic messages etc.  Programmers
  2320 rarely need to care about Output.output or Output.raw at all, with
  2321 some notable exceptions: Output.output is required when bypassing the
  2322 standard channels (writeln etc.), or in token translations to produce
  2323 properly formatted results; Output.raw is required when capturing
  2324 already output material that will eventually be presented to the user
  2325 a second time.  For the default print mode, both Output.output and
  2326 Output.raw have no effect.
  2327 
  2328 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2329 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2330 cumulative results are displayed at the end of a batch session.
  2331 
  2332 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2333 replaced by File.platform_path and File.shell_path (with appropriate
  2334 hooks).  This provides a clean interface for unusual systems where the
  2335 internal and external process view of file names are different.
  2336 
  2337 * Pure: more efficient orders for basic syntactic entities: added
  2338 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2339 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2340 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2341 orders now -- potential INCOMPATIBILITY for code that depends on a
  2342 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2343 Library.sort_strings on result).
  2344 
  2345 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2346 fold_types traverse types/terms from left to right, observing natural
  2347 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2348 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2349 
  2350 * Pure: name spaces have been refined, with significant changes of the
  2351 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2352 to extern(_table).  The plain name entry path is superceded by a
  2353 general 'naming' context, which also includes the 'policy' to produce
  2354 a fully qualified name and external accesses of a fully qualified
  2355 name; NameSpace.extend is superceded by context dependent
  2356 Sign.declare_name.  Several theory and proof context operations modify
  2357 the naming context.  Especially note Theory.restore_naming and
  2358 ProofContext.restore_naming to get back to a sane state; note that
  2359 Theory.add_path is no longer sufficient to recover from
  2360 Theory.absolute_path in particular.
  2361 
  2362 * Pure: new flags short_names (default false) and unique_names
  2363 (default true) for controlling output of qualified names.  If
  2364 short_names is set, names are printed unqualified.  If unique_names is
  2365 reset, the name prefix is reduced to the minimum required to achieve
  2366 the original result when interning again, even if there is an overlap
  2367 with earlier declarations.
  2368 
  2369 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2370 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2371 (useful for printing error messages).  INCOMPATIBILITY.
  2372 
  2373 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2374 Theory.theory are now identified, referring to the universal
  2375 Context.theory (see Pure/context.ML).  Actual signature and theory
  2376 content is managed as theory data.  The old code and interfaces were
  2377 spread over many files and structures; the new arrangement introduces
  2378 considerable INCOMPATIBILITY to gain more clarity:
  2379 
  2380   Context -- theory management operations (name, identity, inclusion,
  2381     parents, ancestors, merge, etc.), plus generic theory data;
  2382 
  2383   Sign -- logical signature and syntax operations (declaring consts,
  2384     types, etc.), plus certify/read for common entities;
  2385 
  2386   Theory -- logical theory operations (stating axioms, definitions,
  2387     oracles), plus a copy of logical signature operations (consts,
  2388     types, etc.); also a few basic management operations (Theory.copy,
  2389     Theory.merge, etc.)
  2390 
  2391 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2392 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2393 for convenience -- they merely return the theory.
  2394 
  2395 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2396 
  2397 * Pure: the Isar proof context type is already defined early in Pure
  2398 as Context.proof (note that ProofContext.context and Proof.context are
  2399 aliases, where the latter is the preferred name).  This enables other
  2400 Isabelle components to refer to that type even before Isar is present.
  2401 
  2402 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2403 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2404 any of these kinds.  For example, Sign.intern typeK is now
  2405 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2406 Theory.hide_types.  Also note that former
  2407 Theory.hide_classes/types/consts are now
  2408 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2409 internalize their arguments!  INCOMPATIBILITY.
  2410 
  2411 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2412 datatype thmref (with constructors Name and NameSelection) instead of
  2413 plain string -- INCOMPATIBILITY;
  2414 
  2415 * Pure: cases produced by proof methods specify options, where NONE
  2416 means to remove case bindings -- INCOMPATIBILITY in
  2417 (RAW_)METHOD_CASES.
  2418 
  2419 * Pure: the following operations retrieve axioms or theorems from a
  2420 theory node or theory hierarchy, respectively:
  2421 
  2422   Theory.axioms_of: theory -> (string * term) list
  2423   Theory.all_axioms_of: theory -> (string * term) list
  2424   PureThy.thms_of: theory -> (string * thm) list
  2425   PureThy.all_thms_of: theory -> (string * thm) list
  2426 
  2427 * Pure: print_tac now outputs the goal through the trace channel.
  2428 
  2429 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2430 Reference Toplevel.debug (default false) controls detailed printing
  2431 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2432 controls execution profiling -- set to 1 for time and 2 for space
  2433 (both increase the runtime).
  2434 
  2435 * Isar session: The initial use of ROOT.ML is now always timed,
  2436 i.e. the log will show the actual process times, in contrast to the
  2437 elapsed wall-clock time that the outer shell wrapper produces.
  2438 
  2439 * Simplifier: improved handling of bound variables (nameless
  2440 representation, avoid allocating new strings).  Simprocs that invoke
  2441 the Simplifier recursively should use Simplifier.inherit_bounds to
  2442 avoid local name clashes.  Failure to do so produces warnings
  2443 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2444 for further details.
  2445 
  2446 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2447 bindings for all theorems stored within a given theory; this may help
  2448 in porting non-Isar theories to Isar ones, while keeping ML proof
  2449 scripts for the time being.
  2450 
  2451 * ML operator HTML.with_charset specifies the charset begin used for
  2452 generated HTML files.  For example:
  2453 
  2454   HTML.with_charset "utf-8" use_thy "Hebrew";
  2455   HTML.with_charset "utf-8" use_thy "Chinese";
  2456 
  2457 
  2458 *** System ***
  2459 
  2460 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2461 isabelle, isatool etc.).
  2462 
  2463 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2464 isatool doc, isatool mkdir, display_drafts etc.).
  2465 
  2466 * isatool usedir: option -f allows specification of the ML file to be
  2467 used by Isabelle; default is ROOT.ML.
  2468 
  2469 * New isatool version outputs the version identifier of the Isabelle
  2470 distribution being used.
  2471 
  2472 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2473 (containing Boolean satisfiability problems) into Isabelle/HOL
  2474 theories.
  2475 
  2476 
  2477 
  2478 New in Isabelle2004 (April 2004)
  2479 --------------------------------
  2480 
  2481 *** General ***
  2482 
  2483 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2484   Replaces linorder.ML.
  2485 
  2486 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2487   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2488   (\<a>...\<z>), are now considered normal letters, and can therefore
  2489   be used anywhere where an ASCII letter (a...zA...Z) has until
  2490   now. COMPATIBILITY: This obviously changes the parsing of some
  2491   terms, especially where a symbol has been used as a binder, say
  2492   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2493   as an identifier.  Fix it by inserting a space around former
  2494   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2495   existing theory and ML files.
  2496 
  2497 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2498 
  2499 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2500   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2501   a normal (but invisible) letter. For multiple letter subscripts repeat
  2502   \<^isub> like this: x\<^isub>1\<^isub>2.
  2503 
  2504 * Pure: There are now sub-/superscripts that can span more than one
  2505   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2506   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2507   superscript. The new control characters are not identifier parts.
  2508 
  2509 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2510   content of "..." to the latex file instead of \isacntrl... . The "..."
  2511   may consist of any printable characters excluding the end bracket >.
  2512 
  2513 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2514   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2515   declare constants "final", which prevents their being given a definition
  2516   later.  It is useful for constants whose behaviour is fixed axiomatically
  2517   rather than definitionally, such as the meta-logic connectives.
  2518 
  2519 * Pure: 'instance' now handles general arities with general sorts
  2520   (i.e. intersections of classes),
  2521 
  2522 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2523   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2524   It can be changed to alter the colors/layout of generated pages.
  2525 
  2526 
  2527 *** Isar ***
  2528 
  2529 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2530   cut_tac, subgoal_tac and thin_tac:
  2531   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2532     locales are no longer forced to write Isar proof scripts.
  2533     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2534     emulations.
  2535   - INCOMPATIBILITY: names of variables to be instantiated may no
  2536     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2537     This is consistent with the instantiation attribute "where".
  2538 
  2539 * Attributes "where" and "of":
  2540   - Now take type variables of instantiated theorem into account when reading
  2541     the instantiation string.  This fixes a bug that caused instantiated
  2542     theorems to have too special types in some circumstances.
  2543   - "where" permits explicit instantiations of type variables.
  2544 
  2545 * Calculation commands "moreover" and "also" no longer interfere with
  2546   current facts ("this"), admitting arbitrary combinations with "then"
  2547   and derived forms.
  2548 
  2549 * Locales:
  2550   - Goal statements involving the context element "includes" no longer
  2551     generate theorems with internal delta predicates (those ending on
  2552     "_axioms") in the premise.
  2553     Resolve particular premise with <locale>.intro to obtain old form.
  2554   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2555     specification and "includes" elements in goal statement.
  2556   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2557     [intro?] and [elim?] (respectively) by default.
  2558   - Experimental command for instantiation of locales in proof contexts:
  2559         instantiate <label>[<attrs>]: <loc>
  2560     Instantiates locale <loc> and adds all its theorems to the current context
  2561     taking into account their attributes.  Label and attrs are optional
  2562     modifiers, like in theorem declarations.  If present, names of
  2563     instantiated theorems are qualified with <label>, and the attributes
  2564     <attrs> are applied after any attributes these theorems might have already.
  2565       If the locale has assumptions, a chained fact of the form
  2566     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2567     are derived.  The command does not support old-style locales declared
  2568     with "locale (open)".
  2569       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2570 
  2571 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2572   (Isar) contexts.
  2573 
  2574 
  2575 *** HOL ***
  2576 
  2577 * Proof import: new image HOL4 contains the imported library from
  2578   the HOL4 system with about 2500 theorems. It is imported by
  2579   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2580   can be used like any other Isabelle image.  See
  2581   HOL/Import/HOL/README for more information.
  2582 
  2583 * Simplifier:
  2584   - Much improved handling of linear and partial orders.
  2585     Reasoners for linear and partial orders are set up for type classes
  2586     "linorder" and "order" respectively, and are added to the default simpset
  2587     as solvers.  This means that the simplifier can build transitivity chains
  2588     to solve goals from the assumptions.
  2589   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2590     of blast or auto after simplification become unnecessary because the goal
  2591     is solved by simplification already.
  2592 
  2593 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2594     all proved in axiomatic type classes for semirings, rings and fields.
  2595 
  2596 * Numerics:
  2597   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2598     now formalized using the Ring_and_Field theory mentioned above.
  2599   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2600     than before, because now they are set up once in a generic manner.
  2601   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2602     Look for the general versions in Ring_and_Field (and Power if they concern
  2603     exponentiation).
  2604 
  2605 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2606 
  2607 * Records:
  2608   - Record types are now by default printed with their type abbreviation
  2609     instead of the list of all field types. This can be configured via
  2610     the reference "print_record_type_abbr".
  2611   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2612     (not enabled by default).
  2613   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2614     EX x. x = sel r to True (not enabled by default).
  2615   - Tactic "record_split_simp_tac" to split and simplify records added.
  2616 
  2617 * 'specification' command added, allowing for definition by
  2618   specification.  There is also an 'ax_specification' command that
  2619   introduces the new constants axiomatically.
  2620 
  2621 * arith(_tac) is now able to generate counterexamples for reals as well.
  2622 
  2623 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2624 
  2625 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2626   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2627 
  2628 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2629   matrix theory to linear programming.
  2630 
  2631 * Unions and Intersections:
  2632   The latex output syntax of UN and INT has been changed
  2633   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2634   i.e. the index formulae has become a subscript.
  2635   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2636 
  2637 * Unions and Intersections over Intervals:
  2638   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2639   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2640   like in normal math, and corresponding versions for < and for intersection.
  2641 
  2642 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2643   lexicographic dictonary ordering has been added as "lexord".
  2644 
  2645 * ML: the legacy theory structures Int and List have been removed. They had
  2646   conflicted with ML Basis Library structures having the same names.
  2647 
  2648 * 'refute' command added to search for (finite) countermodels.  Only works
  2649   for a fragment of HOL.  The installation of an external SAT solver is
  2650   highly recommended.  See "HOL/Refute.thy" for details.
  2651 
  2652 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2653   formulae under an assignment of free variables to random values.
  2654   In contrast to 'refute', it can deal with inductive datatypes,
  2655   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2656   for examples.
  2657 
  2658 
  2659 *** HOLCF ***
  2660 
  2661 * Streams now come with concatenation and are part of the HOLCF image
  2662 
  2663 
  2664 
  2665 New in Isabelle2003 (May 2003)
  2666 ------------------------------
  2667 
  2668 *** General ***
  2669 
  2670 * Provers/simplifier:
  2671 
  2672   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2673     Assumptions are now subject to complete mutual simplification,
  2674     not just from left to right. The simplifier now preserves
  2675     the order of assumptions.
  2676 
  2677     Potential INCOMPATIBILITY:
  2678 
  2679     -- simp sometimes diverges where the old version did
  2680        not, e.g. invoking simp on the goal
  2681 
  2682         [| P (f x); y = x; f x = f y |] ==> Q
  2683 
  2684        now gives rise to the infinite reduction sequence
  2685 
  2686         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2687 
  2688        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2689        kind of problem.
  2690 
  2691     -- Tactics combining classical reasoner and simplification (such as auto)
  2692        are also affected by this change, because many of them rely on
  2693        simp. They may sometimes diverge as well or yield a different numbers
  2694        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2695        in case of problems. Sometimes subsequent calls to the classical
  2696        reasoner will fail because a preceeding call to the simplifier too
  2697        eagerly simplified the goal, e.g. deleted redundant premises.
  2698 
  2699   - The simplifier trace now shows the names of the applied rewrite rules
  2700 
  2701   - You can limit the number of recursive invocations of the simplifier
  2702     during conditional rewriting (where the simplifie tries to solve the
  2703     conditions before applying the rewrite rule):
  2704     ML "simp_depth_limit := n"
  2705     where n is an integer. Thus you can force termination where previously
  2706     the simplifier would diverge.
  2707 
  2708   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2709 
  2710   - No longer aborts on failed congruence proof.  Instead, the
  2711     congruence is ignored.
  2712 
  2713 * Pure: New generic framework for extracting programs from constructive
  2714   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2715   as HOL/Extraction for some case studies.
  2716 
  2717 * Pure: The main goal of the proof state is no longer shown by default, only
  2718 the subgoals. This behaviour is controlled by a new flag.
  2719    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2720 (ML: Proof.show_main_goal).
  2721 
  2722 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2723 rules whose conclusion matches subgoal 1:
  2724       PG menu: Isabelle/Isar -> Show me -> matching rules
  2725 The rules are ordered by how closely they match the subgoal.
  2726 In particular, rules that solve a subgoal outright are displayed first
  2727 (or rather last, the way they are printed).
  2728 (ML: ProofGeneral.print_intros())
  2729 
  2730 * Pure: New flag trace_unify_fail causes unification to print
  2731 diagnostic information (PG: in trace buffer) when it fails. This is
  2732 useful for figuring out why single step proofs like rule, erule or
  2733 assumption failed.
  2734 
  2735 * Pure: Locale specifications now produce predicate definitions
  2736 according to the body of text (covering assumptions modulo local
  2737 definitions); predicate "loc_axioms" covers newly introduced text,
  2738 while "loc" is cumulative wrt. all included locale expressions; the
  2739 latter view is presented only on export into the global theory
  2740 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2741 on the old view without predicates;
  2742 
  2743 * Pure: predefined locales "var" and "struct" are useful for sharing
  2744 parameters (as in CASL, for example); just specify something like
  2745 ``var x + var y + struct M'' as import;
  2746 
  2747 * Pure: improved thms_containing: proper indexing of facts instead of
  2748 raw theorems; check validity of results wrt. current name space;
  2749 include local facts of proof configuration (also covers active
  2750 locales), cover fixed variables in index; may use "_" in term
  2751 specification; an optional limit for the number of printed facts may
  2752 be given (the default is 40);
  2753 
  2754 * Pure: disallow duplicate fact bindings within new-style theory files
  2755 (batch-mode only);
  2756 
  2757 * Provers: improved induct method: assumptions introduced by case
  2758 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2759 the goal statement); "foo" still refers to all facts collectively;
  2760 
  2761 * Provers: the function blast.overloaded has been removed: all constants
  2762 are regarded as potentially overloaded, which improves robustness in exchange
  2763 for slight decrease in efficiency;
  2764 
  2765 * Provers/linorder: New generic prover for transitivity reasoning over
  2766 linear orders.  Note: this prover is not efficient!
  2767 
  2768 * Isar: preview of problems to finish 'show' now produce an error
  2769 rather than just a warning (in interactive mode);
  2770 
  2771 
  2772 *** HOL ***
  2773 
  2774 * arith(_tac)
  2775 
  2776  - Produces a counter example if it cannot prove a goal.
  2777    Note that the counter example may be spurious if the goal is not a formula
  2778    of quantifier-free linear arithmetic.
  2779    In ProofGeneral the counter example appears in the trace buffer.
  2780 
  2781  - Knows about div k and mod k where k is a numeral of type nat or int.
  2782 
  2783  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2784    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2785    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2786 
  2787 * simp's arithmetic capabilities have been enhanced a bit: it now
  2788 takes ~= in premises into account (by performing a case split);
  2789 
  2790 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2791 are distributed over a sum of terms;
  2792 
  2793 * New tactic "trans_tac" and method "trans" instantiate
  2794 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2795 "<=", "<" and "=").
  2796 
  2797 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2798 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2799 
  2800 * 'typedef' command has new option "open" to suppress the set
  2801 definition;
  2802 
  2803 * functions Min and Max on finite sets have been introduced (theory
  2804 Finite_Set);
  2805 
  2806 * attribute [symmetric] now works for relations as well; it turns
  2807 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2808 
  2809 * induct over a !!-quantified statement (say !!x1..xn):
  2810   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2811 
  2812 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2813 %x. None. Warning: empty_def now refers to the previously hidden definition
  2814 of the empty set.
  2815 
  2816 * Algebra: formalization of classical algebra.  Intended as base for
  2817 any algebraic development in Isabelle.  Currently covers group theory
  2818 (up to Sylow's theorem) and ring theory (Universal Property of
  2819 Univariate Polynomials).  Contributions welcome;
  2820 
  2821 * GroupTheory: deleted, since its material has been moved to Algebra;
  2822 
  2823 * Complex: new directory of the complex numbers with numeric constants,
  2824 nonstandard complex numbers, and some complex analysis, standard and
  2825 nonstandard (Jacques Fleuriot);
  2826 
  2827 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2828 
  2829 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2830 Fleuriot);
  2831 
  2832 * Real/HahnBanach: updated and adapted to locales;
  2833 
  2834 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2835 Gray and Kramer);
  2836 
  2837 * UNITY: added the Meier-Sanders theory of progress sets;
  2838 
  2839 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2840 as abstract algorithms, instantiated to the JVM;
  2841 
  2842 * Bali: Java source language formalization. Type system, operational
  2843 semantics, axiomatic semantics. Supported language features:
  2844 classes, interfaces, objects,virtual methods, static methods,
  2845 static/instance fields, arrays, access modifiers, definite
  2846 assignment, exceptions.
  2847 
  2848 
  2849 *** ZF ***
  2850 
  2851 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2852 universe, etc.);
  2853 
  2854 * Main ZF: virtually all theories converted to new-style format;
  2855 
  2856 
  2857 *** ML ***
  2858 
  2859 * Pure: Tactic.prove provides sane interface for internal proofs;
  2860 omits the infamous "standard" operation, so this is more appropriate
  2861 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2862 
  2863 * Pure: improved error reporting of simprocs;
  2864 
  2865 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2866 up simprocs;
  2867 
  2868 
  2869 *** Document preparation ***
  2870 
  2871 * uses \par instead of \\ for line breaks in theory text. This may
  2872 shift some page breaks in large documents. To get the old behaviour
  2873 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2874 
  2875 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2876 other packages
  2877 
  2878 * \<euro> now needs package babel/greek instead of marvosym (which
  2879 broke \Rightarrow)
  2880 
  2881 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2882 textcomp package)
  2883 
  2884 
  2885 
  2886 New in Isabelle2002 (March 2002)
  2887 --------------------------------
  2888 
  2889 *** Document preparation ***
  2890 
  2891 * greatly simplified document preparation setup, including more
  2892 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2893 instructive isatool mkdir; users should basically be able to get
  2894 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2895 users may run a separate document processing stage manually like this:
  2896 "isatool usedir -D output HOL Test && isatool document Test/output";
  2897 
  2898 * theory dependency graph may now be incorporated into documents;
  2899 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2900 with \includegraphics of LaTeX;
  2901 
  2902 * proper spacing of consecutive markup elements, especially text
  2903 blocks after section headings;
  2904 
  2905 * support bold style (for single symbols only), input syntax is like
  2906 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2907 
  2908 * \<bullet> is now output as bold \cdot by default, which looks much
  2909 better in printed text;
  2910 
  2911 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2912 note that these symbols are currently unavailable in Proof General /
  2913 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2914 
  2915 * isatool latex no longer depends on changed TEXINPUTS, instead
  2916 isatool document copies the Isabelle style files to the target
  2917 location;
  2918 
  2919 
  2920 *** Isar ***
  2921 
  2922 * Pure/Provers: improved proof by cases and induction;
  2923   - 'case' command admits impromptu naming of parameters (such as
  2924     "case (Suc n)");
  2925   - 'induct' method divinates rule instantiation from the inductive
  2926     claim; no longer requires excessive ?P bindings for proper
  2927     instantiation of cases;
  2928   - 'induct' method properly enumerates all possibilities of set/type
  2929     rules; as a consequence facts may be also passed through *type*
  2930     rules without further ado;
  2931   - 'induct' method now derives symbolic cases from the *rulified*
  2932     rule (before it used to rulify cases stemming from the internal
  2933     atomized version); this means that the context of a non-atomic
  2934     statement becomes is included in the hypothesis, avoiding the
  2935     slightly cumbersome show "PROP ?case" form;
  2936   - 'induct' may now use elim-style induction rules without chaining
  2937     facts, using ``missing'' premises from the goal state; this allows
  2938     rules stemming from inductive sets to be applied in unstructured
  2939     scripts, while still benefitting from proper handling of non-atomic
  2940     statements; NB: major inductive premises need to be put first, all
  2941     the rest of the goal is passed through the induction;
  2942   - 'induct' proper support for mutual induction involving non-atomic
  2943     rule statements (uses the new concept of simultaneous goals, see
  2944     below);
  2945   - append all possible rule selections, but only use the first
  2946     success (no backtracking);
  2947   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2948   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2949   - added 'print_induct_rules' (covered by help item in recent Proof
  2950     General versions);
  2951   - moved induct/cases attributes to Pure, methods to Provers;
  2952   - generic method setup instantiated for FOL and HOL;
  2953 
  2954 * Pure: support multiple simultaneous goal statements, for example
  2955 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2956 meta-level mechanism, this acts as if several individual goals had
  2957 been stated separately; in particular common proof methods need to be
  2958 repeated in order to cover all claims; note that a single elimination
  2959 step is *not* sufficient to establish the two conjunctions, so this
  2960 fails:
  2961 
  2962   assume "A & B" then have A and B ..   (*".." fails*)
  2963 
  2964 better use "obtain" in situations as above; alternative refer to
  2965 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2966 
  2967 * Pure: proper integration with ``locales''; unlike the original
  2968 version by Florian Kammller, Isar locales package high-level proof
  2969 contexts rather than raw logical ones (e.g. we admit to include
  2970 attributes everywhere); operations on locales include merge and
  2971 rename; support for implicit arguments (``structures''); simultaneous
  2972 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2973 some examples;
  2974 
  2975 * Pure: the following commands have been ``localized'', supporting a
  2976 target locale specification "(in name)": 'lemma', 'theorem',
  2977 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2978 stored both within the locale and at the theory level (exported and
  2979 qualified by the locale name);
  2980 
  2981 * Pure: theory goals may now be specified in ``long'' form, with
  2982 ad-hoc contexts consisting of arbitrary locale elements. for example
  2983 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2984 definitions may be given, too); the result is a meta-level rule with
  2985 the context elements being discharged in the obvious way;
  2986 
  2987 * Pure: new proof command 'using' allows to augment currently used
  2988 facts after a goal statement ('using' is syntactically analogous to
  2989 'apply', but acts on the goal's facts only); this allows chained facts
  2990 to be separated into parts given before and after a claim, as in
  2991 ``from a and b have C using d and e <proof>'';
  2992 
  2993 * Pure: renamed "antecedent" case to "rule_context";
  2994 
  2995 * Pure: new 'judgment' command records explicit information about the
  2996 object-logic embedding (used by several tools internally); no longer
  2997 use hard-wired "Trueprop";
  2998 
  2999 * Pure: added 'corollary' command;
  3000 
  3001 * Pure: fixed 'token_translation' command;
  3002 
  3003 * Pure: removed obsolete 'exported' attribute;
  3004 
  3005 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3006 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3007 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3008 
  3009 * Pure: method 'atomize' presents local goal premises as object-level
  3010 statements (atomic meta-level propositions); setup controlled via
  3011 rewrite rules declarations of 'atomize' attribute; example
  3012 application: 'induct' method with proper rule statements in improper
  3013 proof *scripts*;
  3014 
  3015 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3016 now consider the syntactic context of assumptions, giving a better
  3017 chance to get type-inference of the arguments right (this is
  3018 especially important for locales);
  3019 
  3020 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3021 mode;
  3022 
  3023 * Pure/obtain: the formal conclusion "thesis", being marked as
  3024 ``internal'', may no longer be reference directly in the text;
  3025 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3026 situations;
  3027 
  3028 * Pure: generic 'sym' attribute which declares a rule both as pure
  3029 'elim?' and for the 'symmetric' operation;
  3030 
  3031 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3032 text; the fixed correlation with particular command syntax has been
  3033 discontinued;
  3034 
  3035 * Pure: new method 'rules' is particularly well-suited for proof
  3036 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3037 but often produces more compact proof terms with less detours;
  3038 
  3039 * Pure/Provers/classical: simplified integration with pure rule
  3040 attributes and methods; the classical "intro?/elim?/dest?"
  3041 declarations coincide with the pure ones; the "rule" method no longer
  3042 includes classically swapped intros; "intro" and "elim" methods no
  3043 longer pick rules from the context; also got rid of ML declarations
  3044 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3045 INCOMPATIBILITY;
  3046 
  3047 * Provers/classical: attribute 'swapped' produces classical inversions
  3048 of introduction rules;
  3049 
  3050 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3051 rules instead of full simplifier context; 'iff' attribute handles
  3052 conditional rules;
  3053 
  3054 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3055 
  3056 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3057 "(permissive)" option to recover old behavior;
  3058 
  3059 * HOL: 'inductive' no longer features separate (collective) attributes
  3060 for 'intros' (was found too confusing);
  3061 
  3062 * HOL: properly declared induction rules less_induct and
  3063 wf_induct_rule;
  3064 
  3065 
  3066 *** HOL ***
  3067 
  3068 * HOL: moved over to sane numeral syntax; the new policy is as
  3069 follows:
  3070 
  3071   - 0 and 1 are polymorphic constants, which are defined on any
  3072   numeric type (nat, int, real etc.);
  3073 
  3074   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3075   binary representation internally;
  3076 
  3077   - type nat has special constructor Suc, and generally prefers Suc 0
  3078   over 1::nat and Suc (Suc 0) over 2::nat;
  3079 
  3080 This change may cause significant problems of INCOMPATIBILITY; here
  3081 are some hints on converting existing sources:
  3082 
  3083   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3084   entities, so expressions involving "-" (unary or binary minus) need
  3085   to be spaced properly;
  3086 
  3087   - existing occurrences of "1" may need to be constraint "1::nat" or
  3088   even replaced by Suc 0; similar for old "2";
  3089 
  3090   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3091 
  3092   - remove all special provisions on numerals in proofs;
  3093 
  3094 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3095 representation (depends on bin_arith_simps in the default context);
  3096 
  3097 * HOL: symbolic syntax for x^2 (numeral 2);
  3098 
  3099 * HOL: the class of all HOL types is now called "type" rather than
  3100 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3101 in axclass/classes, instance/arities, and (usually rare) occurrences
  3102 in typings (of consts etc.); internally the class is called
  3103 "HOL.type", ML programs should refer to HOLogic.typeS;
  3104 
  3105 * HOL/record package improvements:
  3106   - new derived operations "fields" to build a partial record section,
  3107     "extend" to promote a fixed record to a record scheme, and
  3108     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3109     declared as simp by default;
  3110   - shared operations ("more", "fields", etc.) now need to be always
  3111     qualified) --- potential INCOMPATIBILITY;
  3112   - removed "make_scheme" operations (use "make" with "extend") --
  3113     INCOMPATIBILITY;
  3114   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3115   - provides cases/induct rules for use with corresponding Isar
  3116     methods (for concrete records, record schemes, concrete more
  3117     parts, and schematic more parts -- in that order);
  3118   - internal definitions directly based on a light-weight abstract
  3119     theory of product types over typedef rather than datatype;
  3120 
  3121 * HOL: generic code generator for generating executable ML code from
  3122 specifications; specific support for HOL constructs such as inductive
  3123 datatypes and sets, as well as recursive functions; can be invoked
  3124 via 'generate_code' theory section;
  3125 
  3126 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3127 
  3128 * HOL: consolidated and renamed several theories.  In particular:
  3129         Ord.thy has been absorbed into HOL.thy
  3130         String.thy has been absorbed into List.thy
  3131 
  3132 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3133 (beware of argument permutation!);
  3134 
  3135 * HOL: linorder_less_split superseded by linorder_cases;
  3136 
  3137 * HOL/List: "nodups" renamed to "distinct";
  3138 
  3139 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3140 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3141   - Ex_def has changed, now need to use some_eq_ex
  3142 
  3143 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3144 in this (rare) case use:
  3145 
  3146   delSWrapper "split_all_tac"
  3147   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3148 
  3149 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3150 MAY FAIL;
  3151 
  3152 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3153 Isabelle's type classes, ^ on functions and relations has too general
  3154 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3155 necessary to attach explicit type constraints;
  3156 
  3157 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3158 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3159 renamed accordingly (eg "compI" -> "rel_compI").
  3160 
  3161 * HOL: syntax translations now work properly with numerals and records
  3162 expressions;
  3163 
  3164 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3165 of "lam" -- INCOMPATIBILITY;
  3166 
  3167 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3168 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3169 renamed "Product_Type.unit";
  3170 
  3171 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3172 
  3173 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3174 the "cases" method);
  3175 
  3176 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3177 Florian Kammller);
  3178 
  3179 * HOL/IMP: updated and converted to new-style theory format; several
  3180 parts turned into readable document, with proper Isar proof texts and
  3181 some explanations (by Gerwin Klein);
  3182 
  3183 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3184 
  3185 * HOL-Hyperreal is now a logic image;
  3186 
  3187 
  3188 *** HOLCF ***
  3189 
  3190 * Isar: consts/constdefs supports mixfix syntax for continuous
  3191 operations;
  3192 
  3193 * Isar: domain package adapted to new-style theory format, e.g. see
  3194 HOLCF/ex/Dnat.thy;
  3195 
  3196 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3197 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3198 lift.induct_tac, always use UU instead of Undef;
  3199 
  3200 * HOLCF/IMP: updated and converted to new-style theory;
  3201 
  3202 
  3203 *** ZF ***
  3204 
  3205 * Isar: proper integration of logic-specific tools and packages,
  3206 including theory commands '(co)inductive', '(co)datatype',
  3207 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3208 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3209 
  3210 * theory Main no longer includes AC; for the Axiom of Choice, base
  3211 your theory on Main_ZFC;
  3212 
  3213 * the integer library now covers quotients and remainders, with many
  3214 laws relating division to addition, multiplication, etc.;
  3215 
  3216 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3217 typeless version of the formalism;
  3218 
  3219 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3220 format;
  3221 
  3222 * ZF/Induct: new directory for examples of inductive definitions,
  3223 including theory Multiset for multiset orderings; converted to
  3224 new-style theory format;
  3225 
  3226 * ZF: many new theorems about lists, ordinals, etc.;
  3227 
  3228 
  3229 *** General ***
  3230 
  3231 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3232 variable proof controls level of detail: 0 = no proofs (only oracle
  3233 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3234 also ref manual for further ML interfaces;
  3235 
  3236 * Pure/axclass: removed obsolete ML interface
  3237 goal_subclass/goal_arity;
  3238 
  3239 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3240 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3241 separate tokens, so expressions involving minus need to be spaced
  3242 properly;
  3243 
  3244 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3245 rather than "infixl" or "infixr";
  3246 
  3247 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3248 sort constraint specifications in type inference; e.g. "x::_::foo"
  3249 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3250 type variable);
  3251 
  3252 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3253 control output of nested => (types); the default behavior is
  3254 "type_brackets";
  3255 
  3256 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3257 tokens into AST constants;
  3258 
  3259 * Pure/syntax: prefer later declarations of translations and print
  3260 translation functions; potential INCOMPATIBILITY: need to reverse
  3261 multiple declarations for same syntax element constant;
  3262 
  3263 * Pure/show_hyps reset by default (in accordance to existing Isar
  3264 practice);
  3265 
  3266 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3267 addSafter;
  3268 
  3269 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3270 as well;
  3271 
  3272 * system: tested support for MacOS X; should be able to get Isabelle +
  3273 Proof General to work in a plain Terminal after installing Poly/ML
  3274 (e.g. from the Isabelle distribution area) and GNU bash alone
  3275 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3276 support requires further installations, e.g. from
  3277 http://fink.sourceforge.net/);
  3278 
  3279 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3280 
  3281 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3282 of 40 MB), cf. ML_OPTIONS;
  3283 
  3284 * system: Proof General keywords specification is now part of the
  3285 Isabelle distribution (see etc/isar-keywords.el);
  3286 
  3287 * system: support for persistent Proof General sessions (refrain from
  3288 outdating all loaded theories on startup); user may create writable
  3289 logic images like this: ``isabelle -q HOL Test'';
  3290 
  3291 * system: smart selection of Isabelle process versus Isabelle
  3292 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3293 run both "isabelle" and "Isabelle" even if file names are badly
  3294 damaged (executable inspects the case of the first letter of its own
  3295 name); added separate "isabelle-process" and "isabelle-interface";
  3296 
  3297 * system: refrain from any attempt at filtering input streams; no
  3298 longer support ``8bit'' encoding of old isabelle font, instead proper
  3299 iso-latin characters may now be used; the related isatools
  3300 "symbolinput" and "nonascii" have disappeared as well;
  3301 
  3302 * system: removed old "xterm" interface (the print modes "xterm" and
  3303 "xterm_color" are still available for direct use in a suitable
  3304 terminal);
  3305 
  3306 
  3307 
  3308 New in Isabelle99-2 (February 2001)
  3309 -----------------------------------
  3310 
  3311 *** Overview of INCOMPATIBILITIES ***
  3312 
  3313 * HOL: please note that theories in the Library and elsewhere often use the
  3314 new-style (Isar) format; to refer to their theorems in an ML script you must
  3315 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3316 
  3317 * HOL: inductive package no longer splits induction rule aggressively,
  3318 but only as far as specified by the introductions given; the old
  3319 format may be recovered via ML function complete_split_rule or attribute
  3320 'split_rule (complete)';
  3321 
  3322 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3323 gfp_Tarski to gfp_unfold;
  3324 
  3325 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3326 
  3327 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3328 relation); infix "^^" has been renamed "``"; infix "``" has been
  3329 renamed "`"; "univalent" has been renamed "single_valued";
  3330 
  3331 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3332 operation;
  3333 
  3334 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3335 
  3336 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3337 
  3338 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3339 consequence, it is no longer monotonic wrt. the local goal context
  3340 (which is now passed through the inductive cases);
  3341 
  3342 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3343 \<gg> to \<ggreater>;
  3344 
  3345 
  3346 *** Document preparation ***
  3347 
  3348 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3349 available: are "it" for near math-mode best-style output, "sl" for
  3350 slanted text style, and "tt" for plain type-writer; if no
  3351 \isabellestyle command is given, output is according to slanted
  3352 type-writer);
  3353 
  3354 * support sub/super scripts (for single symbols only), input syntax is
  3355 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3356 
  3357 * some more standard symbols; see Appendix A of the system manual for
  3358 the complete list of symbols defined in isabellesym.sty;
  3359 
  3360 * improved isabelle style files; more abstract symbol implementation
  3361 (should now use \isamath{...} and \isatext{...} in custom symbol
  3362 definitions);
  3363 
  3364 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3365 state; Note that presentation of goal states does not conform to
  3366 actual human-readable proof documents.  Please do not include goal
  3367 states into document output unless you really know what you are doing!
  3368 
  3369 * proper indentation of antiquoted output with proportional LaTeX
  3370 fonts;
  3371 
  3372 * no_document ML operator temporarily disables LaTeX document
  3373 generation;
  3374 
  3375 * isatool unsymbolize tunes sources for plain ASCII communication;
  3376 
  3377 
  3378 *** Isar ***
  3379 
  3380 * Pure: Isar now suffers initial goal statements to contain unbound
  3381 schematic variables (this does not conform to actual readable proof
  3382 documents, due to unpredictable outcome and non-compositional proof
  3383 checking); users who know what they are doing may use schematic goals
  3384 for Prolog-style synthesis of proven results;
  3385 
  3386 * Pure: assumption method (an implicit finishing) now handles actual
  3387 rules as well;
  3388 
  3389 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3390 initial goal, declare "that" only as Pure intro (only for single
  3391 steps); the "that" rule assumption may now be involved in implicit
  3392 finishing, thus ".." becomes a feasible for trivial obtains;
  3393 
  3394 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3395 instance proofs may be performed by "..";
  3396 
  3397 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3398 statements as well;
  3399 
  3400 * Pure: more robust selection of calculational rules;
  3401 
  3402 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3403 rule (as well as the assumption rule);
  3404 
  3405 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3406 lemmas, using the graph browser tool;
  3407 
  3408 * Pure: predict failure of "show" in interactive mode;
  3409 
  3410 * Pure: 'thms_containing' now takes actual terms as arguments;
  3411 
  3412 * HOL: improved method 'induct' --- now handles non-atomic goals
  3413 (potential INCOMPATIBILITY); tuned error handling;
  3414 
  3415 * HOL: cases and induct rules now provide explicit hints about the
  3416 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3417 any remaining facts are inserted into the goal verbatim;
  3418 
  3419 * HOL: local contexts (aka cases) may now contain term bindings as
  3420 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3421 the result to be shown in each case;
  3422 
  3423 * HOL: added 'recdef_tc' command;
  3424 
  3425 * isatool convert assists in eliminating legacy ML scripts;
  3426 
  3427 
  3428 *** HOL ***
  3429 
  3430 * HOL/Library: a collection of generic theories to be used together
  3431 with main HOL; the theory loader path already includes this directory
  3432 by default; the following existing theories have been moved here:
  3433 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3434 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3435 
  3436 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3437 modelling and verification task performed in Isabelle/HOL +
  3438 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3439 
  3440 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3441 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3442 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3443 'domain', this makes the theory consistent with mathematical
  3444 literature;
  3445 
  3446 * HOL basics: added overloaded operations "inverse" and "divide"
  3447 (infix "/"), syntax for generic "abs" operation, generic summation
  3448 operator \<Sum>;
  3449 
  3450 * HOL/typedef: simplified package, provide more useful rules (see also
  3451 HOL/subset.thy);
  3452 
  3453 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3454 now expressed as a proper nested rule (old-style tactic scripts may
  3455 require atomize_strip_tac to cope with non-atomic premises);
  3456 
  3457 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3458 to "split_conv" (old name still available for compatibility);
  3459 
  3460 * HOL: improved concrete syntax for strings (e.g. allows translation
  3461 rules with string literals);
  3462 
  3463 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3464  and Fleuriot's mechanization of analysis, including the transcendental
  3465  functions for the reals;
  3466 
  3467 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3468 
  3469 
  3470 *** CTT ***
  3471 
  3472 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3473 "lam" is displayed as TWO lambda-symbols
  3474 
  3475 * CTT: theory Main now available, containing everything (that is, Bool
  3476 and Arith);
  3477 
  3478 
  3479 *** General ***
  3480 
  3481 * Pure: the Simplifier has been implemented properly as a derived rule
  3482 outside of the actual kernel (at last!); the overall performance
  3483 penalty in practical applications is about 50%, while reliability of
  3484 the Isabelle inference kernel has been greatly improved;
  3485 
  3486 * print modes "brackets" and "no_brackets" control output of nested =>
  3487 (types) and ==> (props); the default behaviour is "brackets";
  3488 
  3489 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3490 as assumptions as well;
  3491 
  3492 * system: support Poly/ML 4.0;
  3493 
  3494 * system: isatool install handles KDE version 1 or 2;
  3495 
  3496 
  3497 
  3498 New in Isabelle99-1 (October 2000)
  3499 ----------------------------------
  3500 
  3501 *** Overview of INCOMPATIBILITIES ***
  3502 
  3503 * HOL: simplification of natural numbers is much changed; to partly
  3504 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3505 issue the following ML commands:
  3506 
  3507   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3508   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3509 
  3510 * HOL: simplification no longer dives into case-expressions; this is
  3511 controlled by "t.weak_case_cong" for each datatype t;
  3512 
  3513 * HOL: nat_less_induct renamed to less_induct;
  3514 
  3515 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3516 fixsome to patch .thy and .ML sources automatically;
  3517 
  3518   select_equality  -> some_equality
  3519   select_eq_Ex     -> some_eq_ex
  3520   selectI2EX       -> someI2_ex
  3521   selectI2         -> someI2
  3522   selectI          -> someI
  3523   select1_equality -> some1_equality
  3524   Eps_sym_eq       -> some_sym_eq_trivial
  3525   Eps_eq           -> some_eq_trivial
  3526 
  3527 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3528 
  3529 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3530 instead);
  3531 
  3532 * HOL: the recursion equations generated by 'recdef' are now called
  3533 f.simps instead of f.rules;
  3534 
  3535 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3536 
  3537 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3538 sometimes be needed;
  3539 
  3540 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3541 
  3542 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3543 
  3544 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3545 product is now "<*>" instead of "Times"; the lexicographic product is
  3546 now "<*lex*>" instead of "**";
  3547 
  3548 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3549 of main HOL, but was unused); better use HOL's datatype package;
  3550 
  3551 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3552 the old syntax may be recovered as follows:
  3553 
  3554   syntax (symbols)
  3555     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3556       (infixl "\\<oplus>" 100)
  3557 
  3558 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3559 
  3560 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3561 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3562 internally;
  3563 
  3564 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3565 changed from A/r to A//r;
  3566 
  3567 * ZF: new treatment of arithmetic (nat & int) may break some old
  3568 proofs;
  3569 
  3570 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3571 rulify -> rule_format, elimify -> elim_format, ...);
  3572 
  3573 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3574 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3575 should have to change intro!! to intro? only); replaced "delrule" by
  3576 "rule del";
  3577 
  3578 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3579 
  3580 * Provers: strengthened force_tac by using new first_best_tac;
  3581 
  3582 * LaTeX document preparation: several changes of isabelle.sty (see
  3583 lib/texinputs);
  3584 
  3585 
  3586 *** Document preparation ***
  3587 
  3588 * formal comments (text blocks etc.) in new-style theories may now
  3589 contain antiquotations of thm/prop/term/typ/text to be presented
  3590 according to latex print mode; concrete syntax is like this:
  3591 @{term[show_types] "f(x) = a + x"};
  3592 
  3593 * isatool mkdir provides easy setup of Isabelle session directories,
  3594 including proper document sources;
  3595 
  3596 * generated LaTeX sources are now deleted after successful run
  3597 (isatool document -c); may retain a copy somewhere else via -D option
  3598 of isatool usedir;
  3599 
  3600 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3601 style files, achieving self-contained LaTeX sources and simplifying
  3602 LaTeX debugging;
  3603 
  3604 * old-style theories now produce (crude) LaTeX output as well;
  3605 
  3606 * browser info session directories are now self-contained (may be put
  3607 on WWW server seperately); improved graphs of nested sessions; removed
  3608 graph for 'all sessions';
  3609 
  3610 * several improvements in isabelle style files; \isabellestyle{it}
  3611 produces fake math mode output; \isamarkupheader is now \section by
  3612 default; see lib/texinputs/isabelle.sty etc.;
  3613 
  3614 
  3615 *** Isar ***
  3616 
  3617 * Isar/Pure: local results and corresponding term bindings are now
  3618 subject to Hindley-Milner polymorphism (similar to ML); this
  3619 accommodates incremental type-inference very nicely;
  3620 
  3621 * Isar/Pure: new derived language element 'obtain' supports
  3622 generalized existence reasoning;
  3623 
  3624 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3625 support accumulation of results, without applying any rules yet;
  3626 useful to collect intermediate results without explicit name
  3627 references, and for use with transitivity rules with more than 2
  3628 premises;
  3629 
  3630 * Isar/Pure: scalable support for case-analysis type proofs: new
  3631 'case' language element refers to local contexts symbolically, as
  3632 produced by certain proof methods; internally, case names are attached
  3633 to theorems as "tags";
  3634 
  3635 * Isar/Pure: theory command 'hide' removes declarations from
  3636 class/type/const name spaces;
  3637 
  3638 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3639 indicate potential overloading;
  3640 
  3641 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3642 
  3643 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3644 "{a,b,c}" instead of {a,b,c};
  3645 
  3646 * Isar/Pure now provides its own version of intro/elim/dest
  3647 attributes; useful for building new logics, but beware of confusion
  3648 with the version in Provers/classical;
  3649 
  3650 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3651 case name 'antecedent';
  3652 
  3653 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3654 to the current context is now done automatically);
  3655 
  3656 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3657 for definining proof methods in ML;
  3658 
  3659 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3660 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3661 most cases, one should have to change intro!! to intro? only);
  3662 replaced "delrule" by "rule del";
  3663 
  3664 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3665 'symmetric' attribute (the latter supercedes [RS sym]);
  3666 
  3667 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3668 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3669 well (including splits);
  3670 
  3671 * Isar/Provers: Simplifier and Classical methods now support all kind
  3672 of modifiers used in the past, including 'cong', 'iff', etc.
  3673 
  3674 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3675 of Simplifier and Classical reasoner);
  3676 
  3677 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3678 now support named cases; major packages (inductive, datatype, primrec,
  3679 recdef) support case names and properly name parameters;
  3680 
  3681 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3682 monotonicity conditions are extracted to be proven at end of
  3683 calculations;
  3684 
  3685 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3686 method anyway;
  3687 
  3688 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3689 split_if split_if_asm; datatype package provides theorems foo.splits =
  3690 foo.split foo.split_asm for each datatype;
  3691 
  3692 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3693 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3694 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3695 use "(cases (simplified))" method in proper proof texts);
  3696 
  3697 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3698 
  3699 * Isar: names of theorems etc. may be natural numbers as well;
  3700 
  3701 * Isar: 'pr' command: optional arguments for goals_limit and
  3702 ProofContext.prems_limit; no longer prints theory contexts, but only
  3703 proof states;
  3704 
  3705 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3706 additional print modes to be specified; e.g. "pr(latex)" will print
  3707 proof state according to the Isabelle LaTeX style;
  3708 
  3709 * Isar: improved support for emulating tactic scripts, including proof
  3710 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3711 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3712 (for HOL datatypes);
  3713 
  3714 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3715 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3716 'proof method scripts' have to be in depth-first order;
  3717 
  3718 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3719 
  3720 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3721 should instead use individual commands for printing items
  3722 (print_commands, print_methods etc.);
  3723 
  3724 * Isar: added 'nothing' --- the empty list of theorems;
  3725 
  3726 
  3727 *** HOL ***
  3728 
  3729 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3730 corresponding virtual machine and a specification of its bytecode
  3731 verifier and a lightweight bytecode verifier, including proofs of
  3732 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3733 Cornelia Pusch (see also the homepage of project Bali at
  3734 http://isabelle.in.tum.de/Bali/);
  3735 
  3736 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3737 Clemens Ballarin;
  3738 
  3739 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3740 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3741 Rasmussen;
  3742 
  3743 * HOL/Lattice: fundamental concepts of lattice theory and order
  3744 structures, including duals, properties of bounds versus algebraic
  3745 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3746 Theorem for complete lattices etc.; may also serve as a demonstration
  3747 for abstract algebraic reasoning using axiomatic type classes, and
  3748 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3749 
  3750 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3751 von Oheimb;
  3752 
  3753 * HOL/IMPP: extension of IMP with local variables and mutually
  3754 recursive procedures, by David von Oheimb;
  3755 
  3756 * HOL/Lambda: converted into new-style theory and document;
  3757 
  3758 * HOL/ex/Multiquote: example of multiple nested quotations and
  3759 anti-quotations -- basically a generalized version of de-Bruijn
  3760 representation; very useful in avoiding lifting of operations;
  3761 
  3762 * HOL/record: added general record equality rule to simpset; fixed
  3763 select-update simplification procedure to handle extended records as
  3764 well; admit "r" as field name;
  3765 
  3766 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3767 other numeric types and also as the identity of groups, rings, etc.;
  3768 
  3769 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3770 Types nat and int belong to this axclass;
  3771 
  3772 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3773    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3774    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3775   two terms #m*u and #n*u are replaced by #(m+n)*u
  3776     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3777   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3778     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3779 
  3780 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3781 powerful prover for predicate logic but knows nothing of clasets; see
  3782 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3783 
  3784 * HOL: new version of "case_tac" subsumes both boolean case split and
  3785 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3786 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3787 
  3788 * HOL: simplification no longer dives into case-expressions: only the
  3789 selector expression is simplified, but not the remaining arms; to
  3790 enable full simplification of case-expressions for datatype t, you may
  3791 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3792 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3793 
  3794 * HOL/recdef: the recursion equations generated by 'recdef' for
  3795 function 'f' are now called f.simps instead of f.rules; if all
  3796 termination conditions are proved automatically, these simplification
  3797 rules are added to the simpset, as in primrec; rules may be named
  3798 individually as well, resulting in a separate list of theorems for
  3799 each equation;
  3800 
  3801 * HOL/While is a new theory that provides a while-combinator. It
  3802 permits the definition of tail-recursive functions without the
  3803 provision of a termination measure. The latter is necessary once the
  3804 invariant proof rule for while is applied.
  3805 
  3806 * HOL: new (overloaded) notation for the set of elements below/above
  3807 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3808 
  3809 * HOL: theorems impI, allI, ballI bound as "strip";
  3810 
  3811 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3812 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3813 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3814 
  3815 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3816 
  3817 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3818 main HOL, but was unused);
  3819 
  3820 * HOL: fewer consts declared as global (e.g. have to refer to
  3821 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3822 
  3823 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3824 in case of overlap with user translations (e.g. judgements over
  3825 tuples); (note that the underlying logical represenation is still
  3826 bogus);
  3827 
  3828 
  3829 *** ZF ***
  3830 
  3831 * ZF: simplification automatically cancels common terms in arithmetic
  3832 expressions over nat and int;
  3833 
  3834 * ZF: new treatment of nat to minimize type-checking: all operators
  3835 coerce their operands to a natural number using the function natify,
  3836 making the algebraic laws unconditional;
  3837 
  3838 * ZF: as above, for int: operators coerce their operands to an integer
  3839 using the function intify;
  3840 
  3841 * ZF: the integer library now contains many of the usual laws for the
  3842 orderings, including $<=, and monotonicity laws for $+ and $*;
  3843 
  3844 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3845 simplification;
  3846 
  3847 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3848 to the simplifier and classical reasoner simultaneously;
  3849 
  3850 
  3851 *** General ***
  3852 
  3853 * Provers: blast_tac now handles actual object-logic rules as
  3854 assumptions; note that auto_tac uses blast_tac internally as well;
  3855 
  3856 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3857 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3858 
  3859 * Provers: delrules now handles destruct rules as well (no longer need
  3860 explicit make_elim);
  3861 
  3862 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3863   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3864 use instead the strong form,
  3865   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3866 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3867 from destruct-rules;
  3868 
  3869 * Provers: Simplifier.easy_setup provides a fast path to basic
  3870 Simplifier setup for new object-logics;
  3871 
  3872 * Pure: AST translation rules no longer require constant head on LHS;
  3873 
  3874 * Pure: improved name spaces: ambiguous output is qualified; support
  3875 for hiding of names;
  3876 
  3877 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3878 XSYMBOL_HOME; no longer need to do manual configuration in most
  3879 situations;
  3880 
  3881 * system: compression of ML heaps images may now be controlled via -c
  3882 option of isabelle and isatool usedir (currently only observed by
  3883 Poly/ML);
  3884 
  3885 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3886 useful for remote X11);
  3887 
  3888 * system: provide TAGS file for Isabelle sources;
  3889 
  3890 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3891 order;
  3892 
  3893 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3894 timing flag supersedes proof_timing and Toplevel.trace;
  3895 
  3896 * ML: new combinators |>> and |>>> for incremental transformations
  3897 with secondary results (e.g. certain theory extensions):
  3898 
  3899 * ML: PureThy.add_defs gets additional argument to indicate potential
  3900 overloading (usually false);
  3901 
  3902 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3903 results;
  3904 
  3905 
  3906 
  3907 New in Isabelle99 (October 1999)
  3908 --------------------------------
  3909 
  3910 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3911 
  3912 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3913 are no longer simplified.  (This allows the simplifier to unfold recursive
  3914 functional programs.)  To restore the old behaviour, declare
  3915 
  3916     Delcongs [if_weak_cong];
  3917 
  3918 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3919 complement;
  3920 
  3921 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3922 
  3923 * HOL/datatype: mutual_induct_tac no longer exists --
  3924   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3925 
  3926 * HOL/typedef: fixed type inference for representing set; type
  3927 arguments now have to occur explicitly on the rhs as type constraints;
  3928 
  3929 * ZF: The con_defs part of an inductive definition may no longer refer
  3930 to constants declared in the same theory;
  3931 
  3932 * HOL, ZF: the function mk_cases, generated by the inductive
  3933 definition package, has lost an argument.  To simplify its result, it
  3934 uses the default simpset instead of a supplied list of theorems.
  3935 
  3936 * HOL/List: the constructors of type list are now Nil and Cons;
  3937 
  3938 * Simplifier: the type of the infix ML functions
  3939         setSSolver addSSolver setSolver addSolver
  3940 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3941 for packaging solvers. A solver is created via
  3942         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3943 where the string argument is only a comment.
  3944 
  3945 
  3946 *** Proof tools ***
  3947 
  3948 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3949 decision procedure for linear arithmetic. Currently it is used for
  3950 types `nat', `int', and `real' in HOL (see below); it can, should and
  3951 will be instantiated for other types and logics as well.
  3952 
  3953 * The simplifier now accepts rewrite rules with flexible heads, eg
  3954      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3955   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3956   matching.
  3957 
  3958 
  3959 *** General ***
  3960 
  3961 * New Isabelle/Isar subsystem provides an alternative to traditional
  3962 tactical theorem proving; together with the ProofGeneral/isar user
  3963 interface it offers an interactive environment for developing human
  3964 readable proof documents (Isar == Intelligible semi-automated
  3965 reasoning); for further information see isatool doc isar-ref,
  3966 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3967 
  3968 * improved and simplified presentation of theories: better HTML markup
  3969 (including colors), graph views in several sizes; isatool usedir now
  3970 provides a proper interface for user theories (via -P option); actual
  3971 document preparation based on (PDF)LaTeX is available as well (for
  3972 new-style theories only); see isatool doc system for more information;
  3973 
  3974 * native support for Proof General, both for classic Isabelle and
  3975 Isabelle/Isar;
  3976 
  3977 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3978 using the graph browser tool;
  3979 
  3980 * Isabelle manuals now also available as PDF;
  3981 
  3982 * theory loader rewritten from scratch (may not be fully
  3983 bug-compatible); old loadpath variable has been replaced by show_path,
  3984 add_path, del_path, reset_path functions; new operations such as
  3985 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3986 isatool doc ref);
  3987 
  3988 * improved isatool install: option -k creates KDE application icon,
  3989 option -p DIR installs standalone binaries;
  3990 
  3991 * added ML_PLATFORM setting (useful for cross-platform installations);
  3992 more robust handling of platform specific ML images for SML/NJ;
  3993 
  3994 * the settings environment is now statically scoped, i.e. it is never
  3995 created again in sub-processes invoked from isabelle, isatool, or
  3996 Isabelle;
  3997 
  3998 * path element specification '~~' refers to '$ISABELLE_HOME';
  3999 
  4000 * in locales, the "assumes" and "defines" parts may be omitted if
  4001 empty;
  4002 
  4003 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4004 long arrows);
  4005 
  4006 * new print_mode "HTML";
  4007 
  4008 * new flag show_tags controls display of tags of theorems (which are
  4009 basically just comments that may be attached by some tools);
  4010 
  4011 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4012 mode and goal output format:
  4013 
  4014 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4015 244c244
  4016 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4017 ---
  4018 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4019 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4020 181c181
  4021 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4022 ---
  4023 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4024 
  4025 * function bind_thms stores lists of theorems (cf. bind_thm);
  4026 
  4027 * new shorthand tactics ftac, eatac, datac, fatac;
  4028 
  4029 * qed (and friends) now accept "" as result name; in that case the
  4030 theorem is not stored, but proper checks and presentation of the
  4031 result still apply;
  4032 
  4033 * theorem database now also indexes constants "Trueprop", "all",
  4034 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4035 
  4036 
  4037 *** HOL ***
  4038 
  4039 ** HOL arithmetic **
  4040 
  4041 * There are now decision procedures for linear arithmetic over nat and
  4042 int:
  4043 
  4044 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4045 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4046 are treated as atomic; subformulae not involving type `nat' or `int'
  4047 are ignored; quantified subformulae are ignored unless they are
  4048 positive universal or negative existential. The tactic has to be
  4049 invoked by hand and can be a little bit slow. In particular, the
  4050 running time is exponential in the number of occurrences of `min' and
  4051 `max', and `-' on `nat'.
  4052 
  4053 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4054 (negated) (in)equalities among the premises and the conclusion into
  4055 account (i.e. no compound formulae) and does not know about `min' and
  4056 `max', and `-' on `nat'. It is fast and is used automatically by the
  4057 simplifier.
  4058 
  4059 NB: At the moment, these decision procedures do not cope with mixed
  4060 nat/int formulae where the two parts interact, such as `m < n ==>
  4061 int(m) < int(n)'.
  4062 
  4063 * HOL/Numeral provides a generic theory of numerals (encoded
  4064 efficiently as bit strings); setup for types nat/int/real is in place;
  4065 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4066 int, existing theories and proof scripts may require a few additional
  4067 type constraints;
  4068 
  4069 * integer division and remainder can now be performed on constant
  4070 arguments;
  4071 
  4072 * many properties of integer multiplication, division and remainder
  4073 are now available;
  4074 
  4075 * An interface to the Stanford Validity Checker (SVC) is available through the
  4076 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4077 are proved automatically.  SVC must be installed separately, and its results
  4078 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4079 invocation of the underlying oracle).  For SVC see
  4080   http://verify.stanford.edu/SVC
  4081 
  4082 * IsaMakefile: the HOL-Real target now builds an actual image;
  4083 
  4084 
  4085 ** HOL misc **
  4086 
  4087 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4088 (in Isabelle/Isar) -- by Gertrud Bauer;
  4089 
  4090 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4091 analysis for assembly languages with subtypes;
  4092 
  4093 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4094 -- avoids syntactic ambiguities and treats state, transition, and
  4095 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4096 changed syntax and (many) tactics;
  4097 
  4098 * HOL/inductive: Now also handles more general introduction rules such
  4099   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4100   theorems are now maintained within the theory (maintained via the
  4101   "mono" attribute);
  4102 
  4103 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4104   (using function types) such as
  4105 
  4106   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4107 
  4108 * HOL/record: record_simproc (part of the default simpset) takes care
  4109 of selectors applied to updated records; record_split_tac is no longer
  4110 part of the default claset; update_defs may now be removed from the
  4111 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4112 
  4113   claset_ref () := claset() addSWrapper record_split_wrapper;
  4114   Delsimprocs [record_simproc]
  4115 
  4116 * HOL/typedef: fixed type inference for representing set; type
  4117 arguments now have to occur explicitly on the rhs as type constraints;
  4118 
  4119 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4120 names rather than an ML expression;
  4121 
  4122 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4123 supplied later.  Program schemes can be defined, such as
  4124     "While B C s = (if B s then While B C (C s) else s)"
  4125 where the well-founded relation can be chosen after B and C have been given.
  4126 
  4127 * HOL/List: the constructors of type list are now Nil and Cons;
  4128 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4129 course, ML tools referring to List.list.op # etc. have to be adapted;
  4130 
  4131 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4132 disabled by default; run isabelle with option -m HOL to get back to
  4133 the original Gordon/HOL-style output;
  4134 
  4135 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4136 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4137 
  4138 * HOL basic syntax simplified (more orthogonal): all variants of
  4139 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4140 Eps operator is provided as well: "SOME x. P[x]";
  4141 
  4142 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4143 
  4144 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4145 thus available for user theories;
  4146 
  4147 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4148 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4149 time;
  4150 
  4151 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4152 several times and then mp;
  4153 
  4154 
  4155 *** LK ***
  4156 
  4157 * the notation <<...>> is now available as a notation for sequences of
  4158 formulas;
  4159 
  4160 * the simplifier is now installed
  4161 
  4162 * the axiom system has been generalized (thanks to Soren Heilmann)
  4163 
  4164 * the classical reasoner now has a default rule database
  4165 
  4166 
  4167 *** ZF ***
  4168 
  4169 * new primrec section allows primitive recursive functions to be given
  4170 directly (as in HOL) over datatypes and the natural numbers;
  4171 
  4172 * new tactics induct_tac and exhaust_tac for induction (or case
  4173 analysis) over datatypes and the natural numbers;
  4174 
  4175 * the datatype declaration of type T now defines the recursor T_rec;
  4176 
  4177 * simplification automatically does freeness reasoning for datatype
  4178 constructors;
  4179 
  4180 * automatic type-inference, with AddTCs command to insert new
  4181 type-checking rules;
  4182 
  4183 * datatype introduction rules are now added as Safe Introduction rules
  4184 to the claset;
  4185 
  4186 * the syntax "if P then x else y" is now available in addition to
  4187 if(P,x,y);
  4188 
  4189 
  4190 *** Internal programming interfaces ***
  4191 
  4192 * tuned simplifier trace output; new flag debug_simp;
  4193 
  4194 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4195 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4196 
  4197 * AxClass.axclass_tac lost the theory argument;
  4198 
  4199 * tuned current_goals_markers semantics: begin / end goal avoids
  4200 printing empty lines;
  4201 
  4202 * removed prs and prs_fn hook, which was broken because it did not
  4203 include \n in its semantics, forcing writeln to add one
  4204 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4205 string -> unit if you really want to output text without newline;
  4206 
  4207 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4208 plain output, interface builders may have to enable 'isabelle_font'
  4209 mode to get Isabelle font glyphs as before;
  4210 
  4211 * refined token_translation interface; INCOMPATIBILITY: output length
  4212 now of type real instead of int;
  4213 
  4214 * theory loader actions may be traced via new ThyInfo.add_hook
  4215 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4216 your own database of information attached to *whole* theories -- as
  4217 opposed to intra-theory data slots offered via TheoryDataFun;
  4218 
  4219 * proper handling of dangling sort hypotheses (at last!);
  4220 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4221 extra sort hypotheses that can be witnessed from the type signature;
  4222 the force_strip_shyps flag is gone, any remaining shyps are simply
  4223 left in the theorem (with a warning issued by strip_shyps_warning);
  4224 
  4225 
  4226 
  4227 New in Isabelle98-1 (October 1998)
  4228 ----------------------------------
  4229 
  4230 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4231 
  4232 * several changes of automated proof tools;
  4233 
  4234 * HOL: major changes to the inductive and datatype packages, including
  4235 some minor incompatibilities of theory syntax;
  4236 
  4237 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4238 called `inj_on';
  4239 
  4240 * HOL: removed duplicate thms in Arith:
  4241   less_imp_add_less  should be replaced by  trans_less_add1
  4242   le_imp_add_le      should be replaced by  trans_le_add1
  4243 
  4244 * HOL: unary minus is now overloaded (new type constraints may be
  4245 required);
  4246 
  4247 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4248 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4249 now taken as an integer constant.
  4250 
  4251 * Pure: ML function 'theory_of' renamed to 'theory';
  4252 
  4253 
  4254 *** Proof tools ***
  4255 
  4256 * Simplifier:
  4257   1. Asm_full_simp_tac is now more aggressive.
  4258      1. It will sometimes reorient premises if that increases their power to
  4259         simplify.
  4260      2. It does no longer proceed strictly from left to right but may also
  4261         rotate premises to achieve further simplification.
  4262      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4263      old Asm_full_simp_tac in that it does not rotate premises.
  4264   2. The simplifier now knows a little bit about nat-arithmetic.
  4265 
  4266 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4267 allows for selected deletion of wrappers, by introduction of names for
  4268 wrapper functionals.  This implies that addbefore, addSbefore,
  4269 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4270 and that adding two tactics with the same name overwrites the first
  4271 one (emitting a warning).
  4272   type wrapper = (int -> tactic) -> (int -> tactic)
  4273   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4274   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4275   delWrapper, delSWrapper: claset *  string            -> claset
  4276   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4277 
  4278 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4279 semantics; addbefore now affects only the unsafe part of step_tac
  4280 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4281 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4282 by Force_tac;
  4283 
  4284 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4285 compWrapper; added safe wrapper (and access functions for it);
  4286 
  4287 * HOL/split_all_tac is now much faster and fails if there is nothing
  4288 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4289 and the names of the automatically generated variables have changed.
  4290 split_all_tac has moved within claset() from unsafe wrappers to safe
  4291 wrappers, which means that !!-bound variables are split much more
  4292 aggressively, and safe_tac and clarify_tac now split such variables.
  4293 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4294 Note: the same holds for record_split_tac, which does the job of
  4295 split_all_tac for record fields.
  4296 
  4297 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4298 permanently to the default simpset using Addsplits just like
  4299 Addsimps. They can be removed via Delsplits just like
  4300 Delsimps. Lower-case versions are also available.
  4301 
  4302 * HOL/Simplifier: The rule split_if is now part of the default
  4303 simpset. This means that the simplifier will eliminate all occurrences
  4304 of if-then-else in the conclusion of a goal. To prevent this, you can
  4305 either remove split_if completely from the default simpset by
  4306 `Delsplits [split_if]' or remove it in a specific call of the
  4307 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4308 other case splitting rules to/from the default simpset: every datatype
  4309 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4310 t is the name of the datatype).
  4311 
  4312 * Classical reasoner / Simplifier combination: new force_tac (and
  4313 derivatives Force_tac, force) combines rewriting and classical
  4314 reasoning (and whatever other tools) similarly to auto_tac, but is
  4315 aimed to solve the given subgoal completely.
  4316 
  4317 
  4318 *** General ***
  4319 
  4320 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4321 and `goalw': the theory is no longer needed as an explicit argument -
  4322 the current theory context is used; assumptions are no longer returned
  4323 at the ML-level unless one of them starts with ==> or !!; it is
  4324 recommended to convert to these new commands using isatool fixgoal
  4325 (backup your sources first!);
  4326 
  4327 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4328 the current theory context, and 'theory' to lookup stored theories;
  4329 
  4330 * new theory section 'locale' for declaring constants, assumptions and
  4331 definitions that have local scope;
  4332 
  4333 * new theory section 'nonterminals' for purely syntactic types;
  4334 
  4335 * new theory section 'setup' for generic ML setup functions
  4336 (e.g. package initialization);
  4337 
  4338 * the distribution now includes Isabelle icons: see
  4339 lib/logo/isabelle-{small,tiny}.xpm;
  4340 
  4341 * isatool install - install binaries with absolute references to
  4342 ISABELLE_HOME/bin;
  4343 
  4344 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4345 
  4346 * print mode 'emacs' reserved for Isamode;
  4347 
  4348 * support multiple print (ast) translations per constant name;
  4349 
  4350 * theorems involving oracles are now printed with a suffixed [!];
  4351 
  4352 
  4353 *** HOL ***
  4354 
  4355 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4356 
  4357 * HOL/inductive package reorganized and improved: now supports mutual
  4358 definitions such as
  4359 
  4360   inductive EVEN ODD
  4361     intrs
  4362       null "0 : EVEN"
  4363       oddI "n : EVEN ==> Suc n : ODD"
  4364       evenI "n : ODD ==> Suc n : EVEN"
  4365 
  4366 new theorem list "elims" contains an elimination rule for each of the
  4367 recursive sets; inductive definitions now handle disjunctive premises
  4368 correctly (also ZF);
  4369 
  4370 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4371 "mutual_induct" no longer exists - the induction rule is always
  4372 contained in "induct";
  4373 
  4374 
  4375 * HOL/datatype package re-implemented and greatly improved: now
  4376 supports mutually recursive datatypes such as
  4377 
  4378   datatype
  4379     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4380             | SUM ('a aexp) ('a aexp)
  4381             | DIFF ('a aexp) ('a aexp)
  4382             | NUM 'a
  4383   and
  4384     'a bexp = LESS ('a aexp) ('a aexp)
  4385             | AND ('a bexp) ('a bexp)
  4386             | OR ('a bexp) ('a bexp)
  4387 
  4388 as well as indirectly recursive datatypes such as
  4389 
  4390   datatype
  4391     ('a, 'b) term = Var 'a
  4392                   | App 'b ((('a, 'b) term) list)
  4393 
  4394 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4395 induction on mutually / indirectly recursive datatypes.
  4396 
  4397 Primrec equations are now stored in theory and can be accessed via
  4398 <function_name>.simps.
  4399 
  4400 INCOMPATIBILITIES:
  4401 
  4402   - Theories using datatypes must now have theory Datatype as an
  4403     ancestor.
  4404   - The specific <typename>.induct_tac no longer exists - use the
  4405     generic induct_tac instead.
  4406   - natE has been renamed to nat.exhaust - use exhaust_tac
  4407     instead of res_inst_tac ... natE. Note that the variable
  4408     names in nat.exhaust differ from the names in natE, this
  4409     may cause some "fragile" proofs to fail.
  4410   - The theorems split_<typename>_case and split_<typename>_case_asm
  4411     have been renamed to <typename>.split and <typename>.split_asm.
  4412   - Since default sorts of type variables are now handled correctly,
  4413     some datatype definitions may have to be annotated with explicit
  4414     sort constraints.
  4415   - Primrec definitions no longer require function name and type
  4416     of recursive argument.
  4417 
  4418 Consider using isatool fixdatatype to adapt your theories and proof
  4419 scripts to the new package (backup your sources first!).
  4420 
  4421 
  4422 * HOL/record package: considerably improved implementation; now
  4423 includes concrete syntax for record types, terms, updates; theorems
  4424 for surjective pairing and splitting !!-bound record variables; proof
  4425 support is as follows:
  4426 
  4427   1) standard conversions (selectors or updates applied to record
  4428 constructor terms) are part of the standard simpset;
  4429 
  4430   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4431 made part of standard simpset and claset via addIffs;
  4432 
  4433   3) a tactic for record field splitting (record_split_tac) is part of
  4434 the standard claset (addSWrapper);
  4435 
  4436 To get a better idea about these rules you may retrieve them via
  4437 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4438 the name of your record type.
  4439 
  4440 The split tactic 3) conceptually simplifies by the following rule:
  4441 
  4442   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4443 
  4444 Thus any record variable that is bound by meta-all will automatically
  4445 blow up into some record constructor term, consequently the
  4446 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4447 solve record problems automatically.
  4448 
  4449 
  4450 * reorganized the main HOL image: HOL/Integ and String loaded by
  4451 default; theory Main includes everything;
  4452 
  4453 * automatic simplification of integer sums and comparisons, using cancellation;
  4454 
  4455 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4456 
  4457 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4458 
  4459 * many new identities for unions, intersections, set difference, etc.;
  4460 
  4461 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4462 called split_if, split_split, split_sum_case and split_nat_case (to go
  4463 with add/delsplits);
  4464 
  4465 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4466 (?x::unit) = (); this is made part of the default simpset, which COULD
  4467 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4468 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4469 unit_abs_eta_conv is added in order to counter the effect of
  4470 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4471 %u.f();
  4472 
  4473 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4474 makes more sense);
  4475 
  4476 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4477   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4478   disjointness reasoning but breaking a few old proofs.
  4479 
  4480 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4481 to 'converse' from 'inverse' (for compatibility with ZF and some
  4482 literature);
  4483 
  4484 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4485 the well-founded relation;
  4486 
  4487 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4488     Compl A.  The "Compl" syntax remains available as input syntax for this
  4489     release ONLY.
  4490 
  4491 * HOL/Update: new theory of function updates:
  4492     f(a:=b) == %x. if x=a then b else f x
  4493 may also be iterated as in f(a:=b,c:=d,...);
  4494 
  4495 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4496 
  4497 * HOL/List:
  4498   - new function list_update written xs[i:=v] that updates the i-th
  4499     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4500   - new function `upt' written [i..j(] which generates the list
  4501     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4502     bound write [i..j], which is a shorthand for [i..j+1(].
  4503   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4504 
  4505 * HOL/Arith:
  4506   - removed 'pred' (predecessor) function;
  4507   - generalized some theorems about n-1;
  4508   - many new laws about "div" and "mod";
  4509   - new laws about greatest common divisors (see theory ex/Primes);
  4510 
  4511 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4512 instead of "inverse";
  4513 
  4514 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4515   of the multiset ordering;
  4516 
  4517 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4518   (not included by default);
  4519 
  4520 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4521 
  4522 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4523   programs, i.e. different program variables may have different types.
  4524 
  4525 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4526   [previously, this check worked only if the rewrite rule was unconditional]
  4527   Now rew can involve either definitions or equalities (either == or =).
  4528 
  4529 
  4530 *** ZF ***
  4531 
  4532 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4533   only the theorems proved on ZF.ML;
  4534 
  4535 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4536   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4537   disjointness reasoning but breaking a few old proofs.
  4538 
  4539 * ZF/Update: new theory of function updates
  4540     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4541   may also be iterated as in f(a:=b,c:=d,...);
  4542 
  4543 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4544 
  4545 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4546   [previously, this check worked only if the rewrite rule was unconditional]
  4547   Now rew can involve either definitions or equalities (either == or =).
  4548 
  4549 * case_tac provided for compatibility with HOL
  4550     (like the old excluded_middle_tac, but with subgoals swapped)
  4551 
  4552 
  4553 *** Internal programming interfaces ***
  4554 
  4555 * Pure: several new basic modules made available for general use, see
  4556 also src/Pure/README;
  4557 
  4558 * improved the theory data mechanism to support encapsulation (data
  4559 kind name replaced by private Object.kind, acting as authorization
  4560 key); new type-safe user interface via functor TheoryDataFun; generic
  4561 print_data function becomes basically useless;
  4562 
  4563 * removed global_names compatibility flag -- all theory declarations
  4564 are qualified by default;
  4565 
  4566 * module Pure/Syntax now offers quote / antiquote translation
  4567 functions (useful for Hoare logic etc. with implicit dependencies);
  4568 see HOL/ex/Antiquote for an example use;
  4569 
  4570 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4571 cterm -> thm;
  4572 
  4573 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4574 subgoal;
  4575 
  4576 * Display.print_goals function moved to Locale.print_goals;
  4577 
  4578 * standard print function for goals supports current_goals_markers
  4579 variable for marking begin of proof, end of proof, start of goal; the
  4580 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4581 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4582 for example;
  4583 
  4584 
  4585 
  4586 New in Isabelle98 (January 1998)
  4587 --------------------------------
  4588 
  4589 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4590 
  4591 * changed lexical syntax of terms / types: dots made part of long
  4592 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4593 
  4594 * simpset (and claset) reference variable replaced by functions
  4595 simpset / simpset_ref;
  4596 
  4597 * no longer supports theory aliases (via merge) and non-trivial
  4598 implicit merge of thms' signatures;
  4599 
  4600 * most internal names of constants changed due to qualified names;
  4601 
  4602 * changed Pure/Sequence interface (see Pure/seq.ML);
  4603 
  4604 
  4605 *** General Changes ***
  4606 
  4607 * hierachically structured name spaces (for consts, types, axms, thms
  4608 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4609 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4610 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4611 long_names for fully qualified output names; NOTE: ML programs
  4612 (special tactics, packages etc.) referring to internal names may have
  4613 to be adapted to cope with fully qualified names; in case of severe
  4614 backward campatibility problems try setting 'global_names' at compile
  4615 time to have enrything declared within a flat name space; one may also
  4616 fine tune name declarations in theories via the 'global' and 'local'
  4617 section;
  4618 
  4619 * reimplemented the implicit simpset and claset using the new anytype
  4620 data filed in signatures; references simpset:simpset ref etc. are
  4621 replaced by functions simpset:unit->simpset and
  4622 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4623 to patch your ML files accordingly;
  4624 
  4625 * HTML output now includes theory graph data for display with Java
  4626 applet or isatool browser; data generated automatically via isatool
  4627 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4628 
  4629 * defs may now be conditional; improved rewrite_goals_tac to handle
  4630 conditional equations;
  4631 
  4632 * defs now admits additional type arguments, using TYPE('a) syntax;
  4633 
  4634 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4635 creates a new theory node; implicit merge of thms' signatures is
  4636 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4637 transfer:theory->thm->thm in (rare) cases;
  4638 
  4639 * improved handling of draft signatures / theories; draft thms (and
  4640 ctyps, cterms) are automatically promoted to real ones;
  4641 
  4642 * slightly changed interfaces for oracles: admit many per theory, named
  4643 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4644 
  4645 * print_goals: optional output of const types (set show_consts and
  4646 show_types);
  4647 
  4648 * improved output of warnings (###) and errors (***);
  4649 
  4650 * subgoal_tac displays a warning if the new subgoal has type variables;
  4651 
  4652 * removed old README and Makefiles;
  4653 
  4654 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4655 
  4656 * removed obsolete init_pps and init_database;
  4657 
  4658 * deleted the obsolete tactical STATE, which was declared by
  4659     fun STATE tacfun st = tacfun st st;
  4660 
  4661 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4662 (which abbreviates $HOME);
  4663 
  4664 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4665 use isatool fixseq to adapt your ML programs (this works for fully
  4666 qualified references to the Sequence structure only!);
  4667 
  4668 * use_thy no longer requires writable current directory; it always
  4669 reloads .ML *and* .thy file, if either one is out of date;
  4670 
  4671 
  4672 *** Classical Reasoner ***
  4673 
  4674 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4675 tactics that use classical reasoning to simplify a subgoal without
  4676 splitting it into several subgoals;
  4677 
  4678 * Safe_tac: like safe_tac but uses the default claset;
  4679 
  4680 
  4681 *** Simplifier ***
  4682 
  4683 * added simplification meta rules:
  4684     (asm_)(full_)simplify: simpset -> thm -> thm;
  4685 
  4686 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4687 logics (again);
  4688 
  4689 * added prems argument to simplification procedures;
  4690 
  4691 * HOL, FOL, ZF: added infix function `addsplits':
  4692   instead of `<simpset> setloop (split_tac <thms>)'
  4693   you can simply write `<simpset> addsplits <thms>'
  4694 
  4695 
  4696 *** Syntax ***
  4697 
  4698 * TYPE('a) syntax for type reflection terms;
  4699 
  4700 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4701 
  4702 * pretty printer: changed order of mixfix annotation preference (again!);
  4703 
  4704 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4705 
  4706 
  4707 *** HOL ***
  4708 
  4709 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4710   with `addloop' of the simplifier to faciliate case splitting in premises.
  4711 
  4712 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4713 
  4714 * HOL/Auth: new protocol proofs including some for the Internet
  4715   protocol TLS;
  4716 
  4717 * HOL/Map: new theory of `maps' a la VDM;
  4718 
  4719 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4720 cancelling out common nat summands from =, <, <= (in)equalities, or
  4721 differences; simplification procedures nat_cancel_factor for
  4722 cancelling common factor from =, <, <= (in)equalities over natural
  4723 sums; nat_cancel contains both kinds of procedures, it is installed by
  4724 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4725 
  4726 * HOL/simplifier: terms of the form
  4727   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4728   are rewritten to
  4729   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4730   and those of the form
  4731   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4732   are rewritten to
  4733   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4734 
  4735 * HOL/datatype
  4736   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4737 
  4738   P(t_case f1 ... fn x) =
  4739      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4740         ...
  4741        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4742      )
  4743 
  4744   and a theorem `split_t_case_asm' of the form
  4745 
  4746   P(t_case f1 ... fn x) =
  4747     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4748         ...
  4749        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4750      )
  4751   which can be added to a simpset via `addsplits'. The existing theorems
  4752   expand_list_case and expand_option_case have been renamed to
  4753   split_list_case and split_option_case.
  4754 
  4755 * HOL/Arithmetic:
  4756   - `pred n' is automatically converted to `n-1'.
  4757     Users are strongly encouraged not to use `pred' any longer,
  4758     because it will disappear altogether at some point.
  4759   - Users are strongly encouraged to write "0 < n" rather than
  4760     "n ~= 0". Theorems and proof tools have been modified towards this
  4761     `standard'.
  4762 
  4763 * HOL/Lists:
  4764   the function "set_of_list" has been renamed "set" (and its theorems too);
  4765   the function "nth" now takes its arguments in the reverse order and
  4766   has acquired the infix notation "!" as in "xs!n".
  4767 
  4768 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4769 
  4770 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4771   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4772 
  4773 * HOL/record: extensible records with schematic structural subtyping
  4774 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4775 still lacks various theorems and concrete record syntax;
  4776 
  4777 
  4778 *** HOLCF ***
  4779 
  4780 * removed "axioms" and "generated by" sections;
  4781 
  4782 * replaced "ops" section by extended "consts" section, which is capable of
  4783   handling the continuous function space "->" directly;
  4784 
  4785 * domain package:
  4786   . proves theorems immediately and stores them in the theory,
  4787   . creates hierachical name space,
  4788   . now uses normal mixfix annotations (instead of cinfix...),
  4789   . minor changes to some names and values (for consistency),
  4790   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4791   . separator between mutual domain defs: changed "," to "and",
  4792   . improved handling of sort constraints;  now they have to
  4793     appear on the left-hand side of the equations only;
  4794 
  4795 * fixed LAM <x,y,zs>.b syntax;
  4796 
  4797 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4798 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4799 
  4800 
  4801 *** FOL and ZF ***
  4802 
  4803 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4804   with `addloop' of the simplifier to faciliate case splitting in premises.
  4805 
  4806 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4807 in HOL, they strip ALL and --> from proved theorems;
  4808 
  4809 
  4810 
  4811 New in Isabelle94-8 (May 1997)
  4812 ------------------------------
  4813 
  4814 *** General Changes ***
  4815 
  4816 * new utilities to build / run / maintain Isabelle etc. (in parts
  4817 still somewhat experimental); old Makefiles etc. still functional;
  4818 
  4819 * new 'Isabelle System Manual';
  4820 
  4821 * INSTALL text, together with ./configure and ./build scripts;
  4822 
  4823 * reimplemented type inference for greater efficiency, better error
  4824 messages and clean internal interface;
  4825 
  4826 * prlim command for dealing with lots of subgoals (an easier way of
  4827 setting goals_limit);
  4828 
  4829 
  4830 *** Syntax ***
  4831 
  4832 * supports alternative (named) syntax tables (parser and pretty
  4833 printer); internal interface is provided by add_modesyntax(_i);
  4834 
  4835 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4836 be used in conjunction with the Isabelle symbol font; uses the
  4837 "symbols" syntax table;
  4838 
  4839 * added token_translation interface (may translate name tokens in
  4840 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4841 the current print_mode); IMPORTANT: user print translation functions
  4842 are responsible for marking newly introduced bounds
  4843 (Syntax.mark_boundT);
  4844 
  4845 * token translations for modes "xterm" and "xterm_color" that display
  4846 names in bold, underline etc. or colors (which requires a color
  4847 version of xterm);
  4848 
  4849 * infixes may now be declared with names independent of their syntax;
  4850 
  4851 * added typed_print_translation (like print_translation, but may
  4852 access type of constant);
  4853 
  4854 
  4855 *** Classical Reasoner ***
  4856 
  4857 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4858 some limitations.  Blast_tac...
  4859   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4860   + ignores elimination rules that don't have the correct format
  4861         (the conclusion MUST be a formula variable)
  4862   + ignores types, which can make HOL proofs fail
  4863   + rules must not require higher-order unification, e.g. apply_type in ZF
  4864     [message "Function Var's argument not a bound variable" relates to this]
  4865   + its proof strategy is more general but can actually be slower
  4866 
  4867 * substitution with equality assumptions no longer permutes other
  4868 assumptions;
  4869 
  4870 * minor changes in semantics of addafter (now called addaltern); renamed
  4871 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4872 (and access functions for it);
  4873 
  4874 * improved combination of classical reasoner and simplifier:
  4875   + functions for handling clasimpsets
  4876   + improvement of addss: now the simplifier is called _after_ the
  4877     safe steps.
  4878   + safe variant of addss called addSss: uses safe simplifications
  4879     _during_ the safe steps. It is more complete as it allows multiple
  4880     instantiations of unknowns (e.g. with slow_tac).
  4881 
  4882 *** Simplifier ***
  4883 
  4884 * added interface for simplification procedures (functions that
  4885 produce *proven* rewrite rules on the fly, depending on current
  4886 redex);
  4887 
  4888 * ordering on terms as parameter (used for ordered rewriting);
  4889 
  4890 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4891 
  4892 * the solver is now split into a safe and an unsafe part.
  4893 This should be invisible for the normal user, except that the
  4894 functions setsolver and addsolver have been renamed to setSolver and
  4895 addSolver; added safe_asm_full_simp_tac;
  4896 
  4897 
  4898 *** HOL ***
  4899 
  4900 * a generic induction tactic `induct_tac' which works for all datatypes and
  4901 also for type `nat';
  4902 
  4903 * a generic case distinction tactic `exhaust_tac' which works for all
  4904 datatypes and also for type `nat';
  4905 
  4906 * each datatype comes with a function `size';
  4907 
  4908 * patterns in case expressions allow tuple patterns as arguments to
  4909 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4910 
  4911 * primrec now also works with type nat;
  4912 
  4913 * recdef: a new declaration form, allows general recursive functions to be
  4914 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4915 
  4916 * the constant for negation has been renamed from "not" to "Not" to
  4917 harmonize with FOL, ZF, LK, etc.;
  4918 
  4919 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4920 infinite lists;
  4921 
  4922 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4923 
  4924 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4925 problems in commutative rings, using axiomatic type classes for + and *;
  4926 
  4927 * more examples in HOL/MiniML and HOL/Auth;
  4928 
  4929 * more default rewrite rules for quantifiers, union/intersection;
  4930 
  4931 * a new constant `arbitrary == @x.False';
  4932 
  4933 * HOLCF/IOA replaces old HOL/IOA;
  4934 
  4935 * HOLCF changes: derived all rules and arities
  4936   + axiomatic type classes instead of classes
  4937   + typedef instead of faking type definitions
  4938   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4939   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4940   + eliminated the types void, one, tr
  4941   + use unit lift and bool lift (with translations) instead of one and tr
  4942   + eliminated blift from Lift3.thy (use Def instead of blift)
  4943   all eliminated rules are derived as theorems --> no visible changes ;
  4944 
  4945 
  4946 *** ZF ***
  4947 
  4948 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4949 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4950 as ZF_cs addSIs [equalityI];
  4951 
  4952 
  4953 
  4954 New in Isabelle94-7 (November 96)
  4955 ---------------------------------
  4956 
  4957 * allowing negative levels (as offsets) in prlev and choplev;
  4958 
  4959 * super-linear speedup for large simplifications;
  4960 
  4961 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4962 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4963 FAIL); can suppress it using the command Delsimps (ex_simps @
  4964 all_simps); De Morgan laws are also now included, by default;
  4965 
  4966 * improved printing of ==>  :  ~:
  4967 
  4968 * new object-logic "Sequents" adds linear logic, while replacing LK
  4969 and Modal (thanks to Sara Kalvala);
  4970 
  4971 * HOL/Auth: correctness proofs for authentication protocols;
  4972 
  4973 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4974 examples on HOL/Auth);
  4975 
  4976 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4977 the rewriter and classical reasoner simultaneously;
  4978 
  4979 * function uresult no longer returns theorems in "standard" format;
  4980 regain previous version by: val uresult = standard o uresult;
  4981 
  4982 
  4983 
  4984 New in Isabelle94-6
  4985 -------------------
  4986 
  4987 * oracles -- these establish an interface between Isabelle and trusted
  4988 external reasoners, which may deliver results as theorems;
  4989 
  4990 * proof objects (in particular record all uses of oracles);
  4991 
  4992 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4993 
  4994 * "constdefs" section in theory files;
  4995 
  4996 * "primrec" section (HOL) no longer requires names;
  4997 
  4998 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4999 
  5000 
  5001 
  5002 New in Isabelle94-5
  5003 -------------------
  5004 
  5005 * reduced space requirements;
  5006 
  5007 * automatic HTML generation from theories;
  5008 
  5009 * theory files no longer require "..." (quotes) around most types;
  5010 
  5011 * new examples, including two proofs of the Church-Rosser theorem;
  5012 
  5013 * non-curried (1994) version of HOL is no longer distributed;
  5014 
  5015 
  5016 
  5017 New in Isabelle94-4
  5018 -------------------
  5019 
  5020 * greatly reduced space requirements;
  5021 
  5022 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5023 
  5024 * searchable theorem database (see the section "Retrieving theorems" on
  5025 page 8 of the Reference Manual);
  5026 
  5027 * new examples, including Grabczewski's monumental case study of the
  5028 Axiom of Choice;
  5029 
  5030 * The previous version of HOL renamed to Old_HOL;
  5031 
  5032 * The new version of HOL (previously called CHOL) uses a curried syntax
  5033 for functions.  Application looks like f a b instead of f(a,b);
  5034 
  5035 * Mutually recursive inductive definitions finally work in HOL;
  5036 
  5037 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5038 translates to the operator "split";
  5039 
  5040 
  5041 
  5042 New in Isabelle94-3
  5043 -------------------
  5044 
  5045 * new infix operator, addss, allowing the classical reasoner to
  5046 perform simplification at each step of its search.  Example:
  5047         fast_tac (cs addss ss)
  5048 
  5049 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5050 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5051 look like (a,b) instead of <a,b>;
  5052 
  5053 * PLEASE NOTE: CHOL will eventually replace HOL!
  5054 
  5055 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5056 It translates to the operator "split".  A new theory of integers is available;
  5057 
  5058 * In ZF, integer numerals now denote two's-complement binary integers.
  5059 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5060 
  5061 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5062 of the Axiom of Choice;
  5063 
  5064 
  5065 
  5066 New in Isabelle94-2
  5067 -------------------
  5068 
  5069 * Significantly faster resolution;
  5070 
  5071 * the different sections in a .thy file can now be mixed and repeated
  5072 freely;
  5073 
  5074 * Database of theorems for FOL, HOL and ZF.  New
  5075 commands including qed, qed_goal and bind_thm store theorems in the database.
  5076 
  5077 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5078 a given theory (thms_of), or find out what theory a theorem was proved in
  5079 (theory_of_thm);
  5080 
  5081 * Bugs fixed in the inductive definition and datatype packages;
  5082 
  5083 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5084 and HOL_dup_cs obsolete;
  5085 
  5086 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5087 have been removed;
  5088 
  5089 * Simpler definition of function space in ZF;
  5090 
  5091 * new results about cardinal and ordinal arithmetic in ZF;
  5092 
  5093 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5094 types;
  5095 
  5096 :mode=text:wrap=hard:maxLineLen=72:
  5097 $Id$