NEWS
author nipkow
Sun Aug 19 21:21:37 2007 +0200 (2007-08-19)
changeset 24331 76f7a8c6e842
parent 24238 ae70f95e31de
child 24333 e77ea0ea7f2c
permissions -rw-r--r--
Made UN_Un simp
     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 * Code generator library theories:
   639   * Pretty_Int represents HOL integers by big integer literals in target
   640     languages.
   641   * Pretty_Char represents HOL characters by character literals in target
   642     languages.
   643   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   644     codes; includes Pretty_Int.
   645   * Executable_Set allows to generate code for finite sets using lists.
   646   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   647     denominator).
   648   * Executable_Real implements a subset of real numbers, namly those
   649     representable by rational numbers.
   650   * Efficient_Nat implements natural numbers by integers, which in general will
   651     result in higher efficency; pattern matching with 0/Suc is eliminated;
   652     includes Pretty_Int.
   653   * ML_String provides an additional datatype ml_string; in the HOL default
   654     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   655     of type ml_string are mapped to strings in SML.
   656   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   657     built-in integers.
   658 
   659 * New package for inductive predicates
   660 
   661   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   662 
   663     inductive
   664       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   665       for z_1 :: U_1 and ... and z_n :: U_m
   666     where
   667       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   668     | ...
   669 
   670   rather than
   671 
   672     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   673 
   674     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   675     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   676 
   677     inductive "s z_1 ... z_m"
   678     intros
   679       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   680       ...
   681 
   682   For backward compatibility, there is a wrapper allowing inductive
   683   sets to be defined with the new package via
   684 
   685     inductive_set
   686       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   687       for z_1 :: U_1 and ... and z_n :: U_m
   688     where
   689       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   690     | ...
   691 
   692   or
   693 
   694     inductive_set
   695       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   696       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   697       for z_1 :: U_1 and ... and z_n :: U_m
   698     where
   699       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   700     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   701     | ...
   702 
   703   if the additional syntax "p ..." is required.
   704 
   705   Many examples can be found in the subdirectories Auth, Bali, Induct,
   706   or MicroJava.
   707 
   708   INCOMPATIBILITIES:
   709 
   710   - Since declaration and definition of inductive sets or predicates
   711     is no longer separated, abbreviations involving the newly introduced
   712     sets or predicates must be specified together with the introduction
   713     rules after the "where" keyword (see example above), rather than before
   714     the actual inductive definition.
   715 
   716   - The variables in induction and elimination rules are now quantified
   717     in the order of their occurrence in the introduction rules, rather than
   718     in alphabetical order. Since this may break some proofs, these proofs
   719     either have to be repaired, e.g. by reordering the variables
   720     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   721 
   722       case (rule_i a_i_1 ... a_i_{k_i})
   723 
   724     or the old order of quantification has to be restored by explicitly adding
   725     meta-level quantifiers in the introduction rules, i.e.
   726 
   727       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   728 
   729   - The format of the elimination rules is now
   730 
   731       p z_1 ... z_m x_1 ... x_n ==>
   732         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   733         ==> ... ==> P
   734 
   735     for predicates and
   736 
   737       (x_1, ..., x_n) : s z_1 ... z_m ==>
   738         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   739         ==> ... ==> P
   740 
   741     for sets rather than
   742 
   743       x : s z_1 ... z_m ==>
   744         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   745         ==> ... ==> P
   746 
   747     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   748     or simplification with the split_paired_all rule) before the above elimination
   749     rule is applicable.
   750 
   751   - The elimination or case analysis rules for (mutually) inductive sets or
   752     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   753     "p_1_..._p_k.elims" is no longer available.
   754 
   755 * Method "metis" proves goals by applying the Metis general-purpose
   756 resolution prover.  Examples are in the directory MetisExamples.  See
   757 also http://gilith.com/software/metis/
   758   
   759 * Command 'sledgehammer' invokes external automatic theorem provers as
   760 background processes.  It generates calls to the "metis" method if
   761 successful. These can be pasted into the proof.  Users do not have to
   762 wait for the automatic provers to return.
   763 
   764 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   765   take their order into account, like in functional programming.
   766   Internally, this is translated into nested case-expressions; missing cases
   767   are added and mapped to the predefined constant "undefined". In complicated
   768   cases printing may no longer show the original input but the internal
   769   form. Lambda-abstractions allow the same form of pattern matching:
   770   "% pat1 => e1 | ..." is an abbreviation for
   771   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   772 
   773 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   774   is an abbreviation for "of_nat :: nat => int". The simplification rules
   775   for "of_nat" have been changed to work like "int" did previously.
   776   (potential INCOMPATIBILITY)
   777   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   778   - of_nat_diff and of_nat_mult are no longer default simp rules
   779 
   780 * Method "algebra" solves polynomial equations over (semi)rings using
   781   Groebner bases. The (semi)ring structure is defined by locales and
   782   the tool setup depends on that generic context. Installing the
   783   method for a specific type involves instantiating the locale and
   784   possibly adding declarations for computation on the coefficients.
   785   The method is already instantiated for natural numbers and for the
   786   axiomatic class of idoms with numerals.  See also the paper by
   787   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   788   underlying this architecture of context-aware proof-tools.
   789 
   790 * constant "List.op @" now named "List.append".  Use ML antiquotations
   791 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   792 possible incompatibilities when working on ML level.
   793 
   794 * Constant renames due to introduction of canonical name prefixing for
   795   class package:
   796 
   797     HOL.abs ~> HOL.minus_class.abs
   798     HOL.divide ~> HOL.divide_class.divide
   799     Nat.power ~> Nat.power_class.power
   800     Nat.size ~> Nat.size_class.size
   801     Numeral.number_of ~> Numeral.number_class.number_of
   802     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   803 
   804 * Rudimentary class target mechanism involves constant renames:
   805 
   806     Orderings.min ~> Orderings.ord_class.min
   807     Orderings.max ~> Orderings.ord_class.max
   808     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   809 
   810 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   811 
   812 * new constant "undefined" with axiom "undefined x = undefined"
   813 
   814 * new class "default" with associated constant "default"
   815 
   816 * new function listsum :: 'a list => 'a for arbitrary monoids.
   817   Special syntax: "SUM x <- xs. f x" (and latex variants)
   818 
   819 * new (input only) syntax for Haskell-like list comprehension, eg
   820   [(x,y). x <- xs, y <- ys, x ~= y]
   821   For details see List.thy.
   822 
   823 * The special syntax for function "filter" has changed from [x : xs. P] to
   824   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   825   and for uniformity. INCOMPATIBILITY
   826 
   827 * Lemma "set_take_whileD" renamed to "set_takeWhileD"
   828 
   829 * New lemma collection field_simps (an extension of ring_simps)
   830   for manipulating (in)equations involving division. Multiplies
   831   with all denominators that can be proved to be non-zero (in equations)
   832   or positive/negative (in inequations).
   833 
   834 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   835   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   836   Removed lemmas field_xyz in Ring_and_Field
   837   because they were subsumed by lemmas xyz.
   838 INCOMPATIBILITY.
   839 
   840 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   841   when generating code.
   842 
   843 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   844   when generating code.
   845 
   846 * Library/Commutative_Ring.thy: switched from recdef to function package;
   847   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   848 
   849 * Some steps towards more uniform lattice theory development in HOL.
   850 
   851     constants "meet" and "join" now named "inf" and "sup"
   852     constant "Meet" now named "Inf"
   853 
   854     classes "meet_semilorder" and "join_semilorder" now named
   855       "lower_semilattice" and "upper_semilattice"
   856     class "lorder" now named "lattice"
   857     class "comp_lat" now named "complete_lattice"
   858 
   859     Instantiation of lattice classes allows explicit definitions
   860     for "inf" and "sup" operations.
   861 
   862   INCOMPATIBILITY.  Theorem renames:
   863 
   864     meet_left_le            ~> inf_le1
   865     meet_right_le           ~> inf_le2
   866     join_left_le            ~> sup_ge1
   867     join_right_le           ~> sup_ge2
   868     meet_join_le            ~> inf_sup_ord
   869     le_meetI                ~> le_infI
   870     join_leI                ~> le_supI
   871     le_meet                 ~> le_inf_iff
   872     le_join                 ~> ge_sup_conv
   873     meet_idempotent         ~> inf_idem
   874     join_idempotent         ~> sup_idem
   875     meet_comm               ~> inf_commute
   876     join_comm               ~> sup_commute
   877     meet_leI1               ~> le_infI1
   878     meet_leI2               ~> le_infI2
   879     le_joinI1               ~> le_supI1
   880     le_joinI2               ~> le_supI2
   881     meet_assoc              ~> inf_assoc
   882     join_assoc              ~> sup_assoc
   883     meet_left_comm          ~> inf_left_commute
   884     meet_left_idempotent    ~> inf_left_idem
   885     join_left_comm          ~> sup_left_commute
   886     join_left_idempotent    ~> sup_left_idem
   887     meet_aci                ~> inf_aci
   888     join_aci                ~> sup_aci
   889     le_def_meet             ~> le_iff_inf
   890     le_def_join             ~> le_iff_sup
   891     join_absorp2            ~> sup_absorb2
   892     join_absorp1            ~> sup_absorb1
   893     meet_absorp1            ~> inf_absorb1
   894     meet_absorp2            ~> inf_absorb2
   895     meet_join_absorp        ~> inf_sup_absorb
   896     join_meet_absorp        ~> sup_inf_absorb
   897     distrib_join_le         ~> distrib_sup_le
   898     distrib_meet_le         ~> distrib_inf_le
   899 
   900     add_meet_distrib_left   ~> add_inf_distrib_left
   901     add_join_distrib_left   ~> add_sup_distrib_left
   902     is_join_neg_meet        ~> is_join_neg_inf
   903     is_meet_neg_join        ~> is_meet_neg_sup
   904     add_meet_distrib_right  ~> add_inf_distrib_right
   905     add_join_distrib_right  ~> add_sup_distrib_right
   906     add_meet_join_distribs  ~> add_sup_inf_distribs
   907     join_eq_neg_meet        ~> sup_eq_neg_inf
   908     meet_eq_neg_join        ~> inf_eq_neg_sup
   909     add_eq_meet_join        ~> add_eq_inf_sup
   910     meet_0_imp_0            ~> inf_0_imp_0
   911     join_0_imp_0            ~> sup_0_imp_0
   912     meet_0_eq_0             ~> inf_0_eq_0
   913     join_0_eq_0             ~> sup_0_eq_0
   914     neg_meet_eq_join        ~> neg_inf_eq_sup
   915     neg_join_eq_meet        ~> neg_sup_eq_inf
   916     join_eq_if              ~> sup_eq_if
   917 
   918     mono_meet               ~> mono_inf
   919     mono_join               ~> mono_sup
   920     meet_bool_eq            ~> inf_bool_eq
   921     join_bool_eq            ~> sup_bool_eq
   922     meet_fun_eq             ~> inf_fun_eq
   923     join_fun_eq             ~> sup_fun_eq
   924     meet_set_eq             ~> inf_set_eq
   925     join_set_eq             ~> sup_set_eq
   926     meet1_iff               ~> inf1_iff
   927     meet2_iff               ~> inf2_iff
   928     meet1I                  ~> inf1I
   929     meet2I                  ~> inf2I
   930     meet1D1                 ~> inf1D1
   931     meet2D1                 ~> inf2D1
   932     meet1D2                 ~> inf1D2
   933     meet2D2                 ~> inf2D2
   934     meet1E                  ~> inf1E
   935     meet2E                  ~> inf2E
   936     join1_iff               ~> sup1_iff
   937     join2_iff               ~> sup2_iff
   938     join1I1                 ~> sup1I1
   939     join2I1                 ~> sup2I1
   940     join1I1                 ~> sup1I1
   941     join2I2                 ~> sup1I2
   942     join1CI                 ~> sup1CI
   943     join2CI                 ~> sup2CI
   944     join1E                  ~> sup1E
   945     join2E                  ~> sup2E
   946 
   947     is_meet_Meet            ~> is_meet_Inf
   948     Meet_bool_def           ~> Inf_bool_def
   949     Meet_fun_def            ~> Inf_fun_def
   950     Meet_greatest           ~> Inf_greatest
   951     Meet_lower              ~> Inf_lower
   952     Meet_set_def            ~> Inf_set_def
   953 
   954     listsp_meetI            ~> listsp_infI
   955     listsp_meet_eq          ~> listsp_inf_eq
   956 
   957     meet_min                ~> inf_min
   958     join_max                ~> sup_max
   959 
   960 * Classes "order" and "linorder": facts "refl", "trans" and
   961 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   962 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   963 
   964 * Classes "order" and "linorder": 
   965 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   966 proofs changed.
   967 
   968 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   969 INCOMPATIBILITY.
   970 
   971 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   972 INCOMPATIBILITY.
   973 
   974 * Added syntactic class "size"; overloaded constant "size" now has
   975 type "'a::size ==> bool"
   976 
   977 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   978 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   979 
   980 * Added method "lexicographic_order" automatically synthesizes
   981 termination relations as lexicographic combinations of size measures
   982 -- 'function' package.
   983 
   984 * HOL/records: generalised field-update to take a function on the
   985 field rather than the new value: r(|A := x|) is translated to A_update
   986 (K x) r The K-combinator that is internally used is called K_record.
   987 INCOMPATIBILITY: Usage of the plain update functions has to be
   988 adapted.
   989  
   990 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   991 0 * x = 0, which are required for a semiring.  Richer structures do
   992 not inherit from semiring_0 anymore, because this property is a
   993 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   994 semiring_0, there is more to prove, but this is mostly trivial.
   995 
   996 * axclass "recpower" was generalized to arbitrary monoids, not just
   997 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   998 commutativity or a semiring property, add the corresponding classes.
   999 
  1000 * Unified locale partial_order with class definition (cf. theory
  1001 Orderings), added parameter ``less''.  INCOMPATIBILITY.
  1002 
  1003 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1004 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
  1005 Isar level, use abbreviations instead.
  1006 
  1007 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
  1008 rarely occuring name references (e.g. ``List.op mem.simps'') require
  1009 renaming (e.g. ``List.memberl.simps'').
  1010 
  1011 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
  1012 INCOMPATIBILITY.
  1013 
  1014 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
  1015 
  1016 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1017 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
  1018 significant changes for setting up numeral syntax for types:
  1019 
  1020   - new constants Numeral.pred and Numeral.succ instead
  1021       of former Numeral.bin_pred and Numeral.bin_succ.
  1022   - Use integer operations instead of bin_add, bin_mult and so on.
  1023   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1024   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1025 
  1026 See HOL/Integ/IntArith.thy for an example setup.
  1027 
  1028 * New top level command 'normal_form' computes the normal form of a
  1029 term that may contain free variables. For example ``normal_form
  1030 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
  1031 suitable for heavy-duty computations because the functions are
  1032 compiled to ML first.
  1033 
  1034 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1035 25 like -->); output depends on the "iff" print_mode, the default is
  1036 "A = B" (with priority 50).
  1037 
  1038 * Renamed constants in HOL.thy and Orderings.thy:
  1039     op +   ~> HOL.plus_class.plus
  1040     op -   ~> HOL.minus_class.minus
  1041     uminus ~> HOL.minus_class.uminus
  1042     abs    ~> HOL.abs_class.abs
  1043     op *   ~> HOL.times_class.times
  1044     op <   ~> HOL.ord_class.less
  1045     op <=  ~> HOL.ord_class.less_eq
  1046 
  1047 Adaptions may be required in the following cases:
  1048 
  1049 a) User-defined constants using any of the names "plus", "minus", "times",
  1050 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
  1051 may go wrong.
  1052 INCOMPATIBILITY: use more specific names.
  1053 
  1054 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1055 INCOMPATIBILITY: use more specific names.
  1056 
  1057 c) Permutative equations (e.g. "a + b = b + a")
  1058 Since the change of names also changes the order of terms, permutative
  1059 rewrite rules may get applied in a different order. Experience shows that
  1060 this is rarely the case (only two adaptions in the whole Isabelle
  1061 distribution).
  1062 INCOMPATIBILITY: rewrite proofs
  1063 
  1064 d) ML code directly refering to constant names
  1065 This in general only affects hand-written proof tactics, simprocs and so on.
  1066 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
  1067 of const_name ML antiquotations.
  1068 
  1069 * Relations less (<) and less_eq (<=) are also available on type bool.
  1070 Modified syntax to disallow nesting without explicit parentheses,
  1071 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
  1072 
  1073 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1074 
  1075 * Relation composition operator "op O" now has precedence 75 and binds
  1076 stronger than union and intersection. INCOMPATIBILITY.
  1077 
  1078 * The old set interval syntax "{m..n(}" (and relatives) has been
  1079 removed.  Use "{m..<n}" (and relatives) instead.
  1080 
  1081 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1082 "t = s" to False (by simproc "neq_simproc").  For backward
  1083 compatibility this can be disabled by ML "reset use_neq_simproc".
  1084 
  1085 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1086 simp.
  1087 
  1088 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1089 
  1090 * Theorem setsum_mult renamed to setsum_right_distrib.
  1091 
  1092 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1093 ``rule'' method.
  1094 
  1095 * Reimplemented methods ``sat'' and ``satx'', with several
  1096 improvements: goals no longer need to be stated as "<prems> ==>
  1097 False", equivalences (i.e. "=" on type bool) are handled, variable
  1098 names of the form "lit_<n>" are no longer reserved, significant
  1099 speedup.
  1100 
  1101 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1102 zChaff is still supported as well.
  1103 
  1104 * 'inductive' and 'datatype': provide projections of mutual rules,
  1105 bundled as foo_bar.inducts;
  1106 
  1107 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1108 Library.
  1109 
  1110 * Library: moved theory Accessible_Part to main HOL.
  1111 
  1112 * Library: added theory Coinductive_List of potentially infinite lists
  1113 as greatest fixed-point.
  1114 
  1115 * Library: added theory AssocList which implements (finite) maps as
  1116 association lists.
  1117 
  1118 * Added proof method ``evaluation'' for efficiently solving a goal
  1119 (i.e. a boolean expression) by compiling it to ML. The goal is
  1120 "proved" (via an oracle) if it evaluates to True.
  1121 
  1122 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1123 also when invoked by the simplifier.  This results in the simplifier
  1124 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1125 fast_arith_split_limit to 0 to obtain the old behavior.
  1126 
  1127 * Support for hex (0x20) and binary (0b1001) numerals.
  1128 
  1129 * New method: reify eqs (t), where eqs are equations for an
  1130 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1131 parameter, computes a term s::'b and a list xs::'a list and proves the
  1132 theorem I xs s = t. This is also known as reification or quoting. The
  1133 resulting theorem is applied to the subgoal to substitute t with I xs
  1134 s.  If t is omitted, the subgoal itself is reified.
  1135 
  1136 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1137 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1138 where f is supposed to be a computable function (in the sense of code
  1139 generattion). The method uses reify to compute s and xs as above then
  1140 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1141 r and finally gets the theorem t = r, which is again applied to the
  1142 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1143 
  1144 * Reflection: Automatic reification now handels binding, an example
  1145 is available in HOL/ex/ReflectionEx.thy
  1146 
  1147 
  1148 *** HOL-Algebra ***
  1149 
  1150 * Formalisation of ideals and the quotient construction over rings.
  1151 
  1152 * Order and lattice theory no longer based on records.
  1153 INCOMPATIBILITY.
  1154 
  1155 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1156 greatest_closed.  INCOMPATIBILITY.
  1157 
  1158 * Method algebra is now set up via an attribute.  For examples see
  1159 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1160 of algebraic structures.
  1161 
  1162 * Renamed theory CRing to Ring.
  1163 
  1164 
  1165 *** HOL-Complex ***
  1166 
  1167 * Theory Real: new method ferrack implements quantifier elimination
  1168 for linear arithmetic over the reals. The quantifier elimination
  1169 feature is used only for decision, for compatibility with arith. This
  1170 means a goal is either solved or left unchanged, no simplification.
  1171 
  1172 * Hyperreal: Functions root and sqrt are now defined on negative real
  1173 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1174 Nonnegativity side conditions have been removed from many lemmas, so
  1175 that more subgoals may now be solved by simplification; potential
  1176 INCOMPATIBILITY.
  1177 
  1178 * Real: New axiomatic classes formalize real normed vector spaces and
  1179 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1180 and norm :: 'a => real.
  1181 
  1182 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1183 from reals into other types. The overloaded constant Reals :: 'a set
  1184 is now defined as range of_real; potential INCOMPATIBILITY.
  1185 
  1186 * Real: ML code generation is supported now and hence also quickcheck.
  1187 Reals are implemented as arbitrary precision rationals.
  1188 
  1189 * Hyperreal: Several constants that previously worked only for the
  1190 reals have been generalized, so they now work over arbitrary vector
  1191 spaces. Type annotations may need to be added in some cases; potential
  1192 INCOMPATIBILITY.
  1193 
  1194   Infinitesimal  :: ('a::real_normed_vector) star set
  1195   HFinite        :: ('a::real_normed_vector) star set
  1196   HInfinite      :: ('a::real_normed_vector) star set
  1197   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1198   monad          :: ('a::real_normed_vector) star => 'a star set
  1199   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1200   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1201   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1202   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1203   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1204   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1205   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1206   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1207   sgn            :: 'a::real_normed_vector => 'a
  1208   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1209 
  1210 * Complex: Some complex-specific constants are now abbreviations for
  1211 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1212 hnorm.  Other constants have been entirely removed in favor of the
  1213 polymorphic versions (INCOMPATIBILITY):
  1214 
  1215   approx        <-- capprox
  1216   HFinite       <-- CFinite
  1217   HInfinite     <-- CInfinite
  1218   Infinitesimal <-- CInfinitesimal
  1219   monad         <-- cmonad
  1220   galaxy        <-- cgalaxy
  1221   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1222   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1223   (ns)deriv     <-- (ns)cderiv
  1224 
  1225 
  1226 *** ML ***
  1227 
  1228 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1229 
  1230 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1231 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1232 init only required for impure data.  INCOMPATIBILITY: empty really
  1233 need to be empty (no dependencies on theory content!)
  1234 
  1235 * ML within Isar: antiquotations allow to embed statically-checked
  1236 formal entities in the source, referring to the context available at
  1237 compile-time.  For example:
  1238 
  1239 ML {* @{typ "'a => 'b"} *}
  1240 ML {* @{term "%x. x"} *}
  1241 ML {* @{prop "x == y"} *}
  1242 ML {* @{ctyp "'a => 'b"} *}
  1243 ML {* @{cterm "%x. x"} *}
  1244 ML {* @{cprop "x == y"} *}
  1245 ML {* @{thm asm_rl} *}
  1246 ML {* @{thms asm_rl} *}
  1247 ML {* @{const_name c} *}
  1248 ML {* @{const_syntax c} *}
  1249 ML {* @{context} *}
  1250 ML {* @{theory} *}
  1251 ML {* @{theory Pure} *}
  1252 ML {* @{simpset} *}
  1253 ML {* @{claset} *}
  1254 ML {* @{clasimpset} *}
  1255 
  1256 The same works for sources being ``used'' within an Isar context.
  1257 
  1258 * ML in Isar: improved error reporting; extra verbosity with
  1259 Toplevel.debug enabled.
  1260 
  1261 * Pure/library:
  1262 
  1263   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1264   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1265 
  1266 The semantics of "burrow" is: "take a function with *simulatanously*
  1267 transforms a list of value, and apply it *simulatanously* to a list of
  1268 list of values of the appropriate type". Compare this with "map" which
  1269 would *not* apply its argument function simulatanously but in
  1270 sequence; "fold_burrow" has an additional context.
  1271 
  1272 * Pure/library: functions map2 and fold2 with curried syntax for
  1273 simultanous mapping and folding:
  1274 
  1275     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1276     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1277 
  1278 * Pure/library: indexed lists - some functions in the Isabelle library
  1279 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1280 given more convenient names and signatures reminiscent of similar
  1281 functions for alists, tables, etc:
  1282 
  1283   val nth: 'a list -> int -> 'a 
  1284   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1285   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1286 
  1287 Note that fold_index starts counting at index 0, not 1 like foldln
  1288 used to.
  1289 
  1290 * Pure/library: added general ``divide_and_conquer'' combinator on
  1291 lists.
  1292 
  1293 * Pure/General/table.ML: the join operations now works via exceptions
  1294 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1295 admits slightly more efficient complex applications.
  1296 
  1297 * Pure: datatype Context.generic joins theory/Proof.context and
  1298 provides some facilities for code that works in either kind of
  1299 context, notably GenericDataFun for uniform theory and proof data.
  1300 
  1301 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1302 use Context.generic instead of just theory.
  1303 
  1304 * Pure: simplified internal attribute type, which is now always
  1305 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1306 vs. local (Proof.context) attributes have been discontinued, while
  1307 minimizing code duplication.  Thm.rule_attribute and
  1308 Thm.declaration_attribute build canonical attributes; see also
  1309 structure Context for further operations on Context.generic, notably
  1310 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1311 declarations and definitions.
  1312 
  1313 * Pure/kernel: consts certification ignores sort constraints given in
  1314 signature declarations.  (This information is not relevant to the
  1315 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1316 potential INCOMPATIBILITY.
  1317 
  1318 * Pure: axiomatic type classes are now purely definitional, with
  1319 explicit proofs of class axioms and super class relations performed
  1320 internally.  See Pure/axclass.ML for the main internal interfaces --
  1321 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1322 AxClass.axiomatize_class/classrel/arity supercede
  1323 Sign.add_classes/classrel/arities.
  1324 
  1325 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1326 global/local versions on theory vs. Proof.context have been
  1327 discontinued; Attrib.syntax and Method.syntax have been adapted
  1328 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1329 attributes, methods, etc.
  1330 
  1331 * Pure: several functions of signature "... -> theory -> theory * ..."
  1332 have been reoriented to "... -> theory -> ... * theory" in order to
  1333 allow natural usage in combination with the ||>, ||>>, |-> and
  1334 fold_map combinators.
  1335 
  1336 * Pure: official theorem names (closed derivations) and additional
  1337 comments (tags) are now strictly separate.  Name hints -- which are
  1338 maintained as tags -- may be attached any time without affecting the
  1339 derivation.
  1340 
  1341 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1342 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1343 achieve the old behaviour.
  1344 
  1345 * Pure: the "Goal" constant is now called "prop", supporting a
  1346 slightly more general idea of ``protecting'' meta-level rule
  1347 statements.
  1348 
  1349 * Pure: Logic.(un)varify only works in a global context, which is now
  1350 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1351 Logic.legacy_(un)varify as temporary workaround.
  1352 
  1353 * Pure: structure Name provides scalable operations for generating
  1354 internal variable names, notably Name.variants etc.  This replaces
  1355 some popular functions from term.ML:
  1356 
  1357   Term.variant		->  Name.variant
  1358   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1359   Term.invent_names	->  Name.invent_list
  1360 
  1361 Note that low-level renaming rarely occurs in new code -- operations
  1362 from structure Variable are used instead (see below).
  1363 
  1364 * Pure: structure Variable provides fundamental operations for proper
  1365 treatment of fixed/schematic variables in a context.  For example,
  1366 Variable.import introduces fixes for schematics of given facts and
  1367 Variable.export reverses the effect (up to renaming) -- this replaces
  1368 various freeze_thaw operations.
  1369 
  1370 * Pure: structure Goal provides simple interfaces for
  1371 init/conclude/finish and tactical prove operations (replacing former
  1372 Tactic.prove).  Goal.prove is the canonical way to prove results
  1373 within a given context; Goal.prove_global is a degraded version for
  1374 theory level goals, including a global Drule.standard.  Note that
  1375 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1376 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1377 in a locale context).
  1378 
  1379 * Isar: simplified treatment of user-level errors, using exception
  1380 ERROR of string uniformly.  Function error now merely raises ERROR,
  1381 without any side effect on output channels.  The Isar toplevel takes
  1382 care of proper display of ERROR exceptions.  ML code may use plain
  1383 handle/can/try; cat_error may be used to concatenate errors like this:
  1384 
  1385   ... handle ERROR msg => cat_error msg "..."
  1386 
  1387 Toplevel ML code (run directly or through the Isar toplevel) may be
  1388 embedded into the Isar toplevel with exception display/debug like
  1389 this:
  1390 
  1391   Isar.toplevel (fn () => ...)
  1392 
  1393 INCOMPATIBILITY, removed special transform_error facilities, removed
  1394 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1395 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1396 -- use plain ERROR instead.
  1397 
  1398 * Isar: theory setup now has type (theory -> theory), instead of a
  1399 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1400 
  1401 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1402 subject to ProofContext.debug/verbose flags.
  1403 
  1404 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1405 theory before entering a proof state.  Transactions now always see a
  1406 quasi-functional intermediate checkpoint, both in interactive and
  1407 batch mode.
  1408 
  1409 * Simplifier: the simpset of a running simplification process now
  1410 contains a proof context (cf. Simplifier.the_context), which is the
  1411 very context that the initial simpset has been retrieved from (by
  1412 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1413 (solver, looper etc.) may depend on arbitrary proof data.
  1414 
  1415 * Simplifier.inherit_context inherits the proof context (plus the
  1416 local bounds) of the current simplification process; any simproc
  1417 etc. that calls the Simplifier recursively should do this!  Removed
  1418 former Simplifier.inherit_bounds, which is already included here --
  1419 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1420 specify an explicit context using Simplifier.context/theory_context.
  1421 
  1422 * Simplifier/Classical Reasoner: more abstract interfaces
  1423 change_simpset/claset for modifying the simpset/claset reference of a
  1424 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1425 INCOMPATIBILITY.
  1426 
  1427 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1428 "Trueprop" etc.
  1429 
  1430 
  1431 *** System ***
  1432 
  1433 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1434 locations -- now includes the Isabelle version identifier as well.
  1435 This simplifies use of multiple Isabelle installations.
  1436 
  1437 * isabelle-process: option -S (secure mode) disables some critical
  1438 operations, notably runtime compilation and evaluation of ML source
  1439 code.
  1440 
  1441 * Experimental support for multithreading, using Poly/ML 5.1 (internal
  1442 version from CVS). The theory loader exploits parallelism when
  1443 processing independent theories, following the header specifications.
  1444 The maximum number of worker threads is specified via usedir option -M
  1445 or the "max-threads" setting in Proof General.  User-code needs to
  1446 observe certain guidelines for thread-safe programming, see appendix A
  1447 in the Isar Implementation manual.
  1448 
  1449 
  1450 New in Isabelle2005 (October 2005)
  1451 ----------------------------------
  1452 
  1453 *** General ***
  1454 
  1455 * Theory headers: the new header syntax for Isar theories is
  1456 
  1457   theory <name>
  1458   imports <theory1> ... <theoryN>
  1459   uses <file1> ... <fileM>
  1460   begin
  1461 
  1462 where the 'uses' part is optional.  The previous syntax
  1463 
  1464   theory <name> = <theory1> + ... + <theoryN>:
  1465 
  1466 will disappear in the next release.  Use isatool fixheaders to convert
  1467 existing theory files.  Note that there is no change in ancient
  1468 non-Isar theories now, but these will disappear soon.
  1469 
  1470 * Theory loader: parent theories can now also be referred to via
  1471 relative and absolute paths.
  1472 
  1473 * Command 'find_theorems' searches for a list of criteria instead of a
  1474 list of constants. Known criteria are: intro, elim, dest, name:string,
  1475 simp:term, and any term. Criteria can be preceded by '-' to select
  1476 theorems that do not match. Intro, elim, dest select theorems that
  1477 match the current goal, name:s selects theorems whose fully qualified
  1478 name contain s, and simp:term selects all simplification rules whose
  1479 lhs match term.  Any other term is interpreted as pattern and selects
  1480 all theorems matching the pattern. Available in ProofGeneral under
  1481 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1482 
  1483   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1484 
  1485 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1486 matching the current goal as introduction rule and not having "HOL."
  1487 in their name (i.e. not being defined in theory HOL).
  1488 
  1489 * Command 'thms_containing' has been discontinued in favour of
  1490 'find_theorems'; INCOMPATIBILITY.
  1491 
  1492 * Communication with Proof General is now 8bit clean, which means that
  1493 Unicode text in UTF-8 encoding may be used within theory texts (both
  1494 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1495 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1496 
  1497   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1498   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1499 
  1500 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1501 Classical Reasoner.  Typical big applications run around 2 times
  1502 faster.
  1503 
  1504 
  1505 *** Document preparation ***
  1506 
  1507 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1508 of raw sources.  Only those symbols that do not require additional
  1509 LaTeX packages (depending on comments in isabellesym.sty) are
  1510 displayed properly, everything else is left verbatim.  isatool display
  1511 and isatool print are used as front ends (these are subject to the
  1512 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1513 
  1514 * Command tags control specific markup of certain regions of text,
  1515 notably folding and hiding.  Predefined tags include "theory" (for
  1516 theory begin and end), "proof" for proof commands, and "ML" for
  1517 commands involving ML code; the additional tags "visible" and
  1518 "invisible" are unused by default.  Users may give explicit tag
  1519 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1520 interpretation of tags is determined by the LaTeX job during document
  1521 preparation: see option -V of isatool usedir, or options -n and -t of
  1522 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1523 \isadroptag.
  1524 
  1525 Several document versions may be produced at the same time via isatool
  1526 usedir (the generated index.html will link all of them).  Typical
  1527 specifications include ''-V document=theory,proof,ML'' to present
  1528 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1529 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1530 these parts without any formal replacement text.  The Isabelle site
  1531 default settings produce ''document'' and ''outline'' versions as
  1532 specified above.
  1533 
  1534 * Several new antiquotations:
  1535 
  1536   @{term_type term} prints a term with its type annotated;
  1537 
  1538   @{typeof term} prints the type of a term;
  1539 
  1540   @{const const} is the same as @{term const}, but checks that the
  1541   argument is a known logical constant;
  1542 
  1543   @{term_style style term} and @{thm_style style thm} print a term or
  1544   theorem applying a "style" to it
  1545 
  1546   @{ML text}
  1547 
  1548 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1549 definitions, equations, inequations etc., 'concl' printing only the
  1550 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1551 to print the specified premise.  TermStyle.add_style provides an ML
  1552 interface for introducing further styles.  See also the "LaTeX Sugar"
  1553 document practical applications.  The ML antiquotation prints
  1554 type-checked ML expressions verbatim.
  1555 
  1556 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1557 and 'text' support optional locale specification '(in loc)', which
  1558 specifies the default context for interpreting antiquotations.  For
  1559 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1560 
  1561 * Option 'locale=NAME' of antiquotations specifies an alternative
  1562 context interpreting the subsequent argument.  For example: @{thm
  1563 [locale=lattice] inf_assoc}.
  1564 
  1565 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1566 a proof context.
  1567 
  1568 * Proper output of antiquotations for theory commands involving a
  1569 proof context (such as 'locale' or 'theorem (in loc) ...').
  1570 
  1571 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1572 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1573 
  1574 * isatool usedir: new option -C (default true) controls whether option
  1575 -D should include a copy of the original document directory; -C false
  1576 prevents unwanted effects such as copying of administrative CVS data.
  1577 
  1578 
  1579 *** Pure ***
  1580 
  1581 * Considerably improved version of 'constdefs' command.  Now performs
  1582 automatic type-inference of declared constants; additional support for
  1583 local structure declarations (cf. locales and HOL records), see also
  1584 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1585 sequential dependencies of definitions within a single 'constdefs'
  1586 section; moreover, the declared name needs to be an identifier.  If
  1587 all fails, consider to fall back on 'consts' and 'defs' separately.
  1588 
  1589 * Improved indexed syntax and implicit structures.  First of all,
  1590 indexed syntax provides a notational device for subscripted
  1591 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1592 expressions.  Secondly, in a local context with structure
  1593 declarations, number indexes \<^sub>n or the empty index (default
  1594 number 1) refer to a certain fixed variable implicitly; option
  1595 show_structs controls printing of implicit structures.  Typical
  1596 applications of these concepts involve record types and locales.
  1597 
  1598 * New command 'no_syntax' removes grammar declarations (and
  1599 translations) resulting from the given syntax specification, which is
  1600 interpreted in the same manner as for the 'syntax' command.
  1601 
  1602 * 'Advanced' translation functions (parse_translation etc.) may depend
  1603 on the signature of the theory context being presently used for
  1604 parsing/printing, see also isar-ref manual.
  1605 
  1606 * Improved 'oracle' command provides a type-safe interface to turn an
  1607 ML expression of type theory -> T -> term into a primitive rule of
  1608 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1609 is already included here); see also FOL/ex/IffExample.thy;
  1610 INCOMPATIBILITY.
  1611 
  1612 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1613 before); "cI" is no longer bound, use "c.intro" instead.
  1614 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1615 axclasses vs. locales.
  1616 
  1617 * Improved internal renaming of symbolic identifiers -- attach primes
  1618 instead of base 26 numbers.
  1619 
  1620 * New flag show_question_marks controls printing of leading question
  1621 marks in schematic variable names.
  1622 
  1623 * In schematic variable names, *any* symbol following \<^isub> or
  1624 \<^isup> is now treated as part of the base name.  For example, the
  1625 following works without printing of awkward ".0" indexes:
  1626 
  1627   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1628     by simp
  1629 
  1630 * Inner syntax includes (*(*nested*) comments*).
  1631 
  1632 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1633 annotations as "(00...)".
  1634 
  1635 * Clear separation of logical types and nonterminals, where the latter
  1636 may only occur in 'syntax' specifications or type abbreviations.
  1637 Before that distinction was only partially implemented via type class
  1638 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1639 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1640 exotic syntax specifications may require further adaption
  1641 (e.g. Cube/Cube.thy).
  1642 
  1643 * Removed obsolete type class "logic", use the top sort {} instead.
  1644 Note that non-logical types should be declared as 'nonterminals'
  1645 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1646 specifications.
  1647 
  1648 * Attributes 'induct' and 'cases': type or set names may now be
  1649 locally fixed variables as well.
  1650 
  1651 * Simplifier: can now control the depth to which conditional rewriting
  1652 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1653 Limit.
  1654 
  1655 * Simplifier: simplification procedures may now take the current
  1656 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1657 interface), which is very useful for calling the Simplifier
  1658 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1659 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1660 low-level mk_simproc no longer applies Logic.varify internally, to
  1661 allow for use in a context of fixed variables.
  1662 
  1663 * thin_tac now works even if the assumption being deleted contains !!
  1664 or ==>.  More generally, erule now works even if the major premise of
  1665 the elimination rule contains !! or ==>.
  1666 
  1667 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1668 
  1669 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1670 from Pure, which contains all common declarations already.  Both
  1671 theories are defined via plain Isabelle/Isar .thy files.
  1672 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1673 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1674 use isatool fixcpure to adapt your theory and ML sources.
  1675 
  1676 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1677 selections of theorems in named facts via index ranges.
  1678 
  1679 * 'print_theorems': in theory mode, really print the difference
  1680 wrt. the last state (works for interactive theory development only),
  1681 in proof mode print all local facts (cf. 'print_facts');
  1682 
  1683 * 'hide': option '(open)' hides only base names.
  1684 
  1685 * More efficient treatment of intermediate checkpoints in interactive
  1686 theory development.
  1687 
  1688 * Code generator is now invoked via code_module (incremental code
  1689 generation) and code_library (modular code generation, ML structures
  1690 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1691 must be quoted when used as identifiers.
  1692 
  1693 * New 'value' command for reading, evaluating and printing terms using
  1694 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1695 quoted when used as identifier.
  1696 
  1697 
  1698 *** Locales ***
  1699 
  1700 * New commands for the interpretation of locale expressions in
  1701 theories (1), locales (2) and proof contexts (3).  These generate
  1702 proof obligations from the expression specification.  After the
  1703 obligations have been discharged, theorems of the expression are added
  1704 to the theory, target locale or proof context.  The synopsis of the
  1705 commands is a follows:
  1706 
  1707   (1) interpretation expr inst
  1708   (2) interpretation target < expr
  1709   (3) interpret expr inst
  1710 
  1711 Interpretation in theories and proof contexts require a parameter
  1712 instantiation of terms from the current context.  This is applied to
  1713 specifications and theorems of the interpreted expression.
  1714 Interpretation in locales only permits parameter renaming through the
  1715 locale expression.  Interpretation is smart in that interpretations
  1716 that are active already do not occur in proof obligations, neither are
  1717 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1718 inspect active interpretations of a particular locale.  For details,
  1719 see the Isar Reference manual.  Examples can be found in
  1720 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1721 
  1722 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1723 'interpret' instead.
  1724 
  1725 * New context element 'constrains' for adding type constraints to
  1726 parameters.
  1727 
  1728 * Context expressions: renaming of parameters with syntax
  1729 redeclaration.
  1730 
  1731 * Locale declaration: 'includes' disallowed.
  1732 
  1733 * Proper static binding of attribute syntax -- i.e. types / terms /
  1734 facts mentioned as arguments are always those of the locale definition
  1735 context, independently of the context of later invocations.  Moreover,
  1736 locale operations (renaming and type / term instantiation) are applied
  1737 to attribute arguments as expected.
  1738 
  1739 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1740 actual attributes; rare situations may require Attrib.attribute to
  1741 embed those attributes into Attrib.src that lack concrete syntax.
  1742 Attribute implementations need to cooperate properly with the static
  1743 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1744 Attrib.XXX_thm etc. already do the right thing without further
  1745 intervention.  Only unusual applications -- such as "where" or "of"
  1746 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1747 on the context and the facts involved -- may have to assign parsed
  1748 values to argument tokens explicitly.
  1749 
  1750 * Changed parameter management in theorem generation for long goal
  1751 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1752 theorem statement in rare situations.
  1753 
  1754 * Locale inspection command 'print_locale' omits notes elements.  Use
  1755 'print_locale!' to have them included in the output.
  1756 
  1757 
  1758 *** Provers ***
  1759 
  1760 * Provers/hypsubst.ML: improved version of the subst method, for
  1761 single-step rewriting: it now works in bound variable contexts. New is
  1762 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1763 rewrite a different subterm than the original subst method, which is
  1764 still available as 'simplesubst'.
  1765 
  1766 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1767 and quasi orders.
  1768 
  1769 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1770 reflexive-transitive closure of relations.
  1771 
  1772 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1773 limit (previously hard-coded with a value of 20) user-definable.
  1774 
  1775 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1776 is peformed already.  Object-logics merely need to finish their
  1777 initial simpset configuration as before.  INCOMPATIBILITY.
  1778 
  1779 
  1780 *** HOL ***
  1781 
  1782 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1783 
  1784   syntax (epsilon)
  1785     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1786 
  1787 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1788 and x-symbol; use option '-m epsilon' to get it actually printed.
  1789 Moreover, the mathematically important symbolic identifier \<epsilon>
  1790 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1791 
  1792 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1793 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1794 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1795 support corresponding Isar calculations.
  1796 
  1797 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1798 instead of ":".
  1799 
  1800 * theory SetInterval: changed the syntax for open intervals:
  1801 
  1802   Old       New
  1803   {..n(}    {..<n}
  1804   {)n..}    {n<..}
  1805   {m..n(}   {m..<n}
  1806   {)m..n}   {m<..n}
  1807   {)m..n(}  {m<..<n}
  1808 
  1809 The old syntax is still supported but will disappear in the next
  1810 release.  For conversion use the following Emacs search and replace
  1811 patterns (these are not perfect but work quite well):
  1812 
  1813   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1814   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1815 
  1816 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1817 equalities in commutative rings; method 'algebra' provides a generic
  1818 interface.
  1819 
  1820 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1821 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1822 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1823 be a tuple pattern.
  1824 
  1825 Some new syntax forms are available:
  1826 
  1827   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1828   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1829   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1830   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1831 
  1832 The latter form "\<Sum>x < k. e" used to be based on a separate
  1833 function "Summation", which has been discontinued.
  1834 
  1835 * theory Finite_Set: in structured induction proofs, the insert case
  1836 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1837 (insert F x)'.
  1838 
  1839 * The 'refute' command has been extended to support a much larger
  1840 fragment of HOL, including axiomatic type classes, constdefs and
  1841 typedefs, inductive datatypes and recursion.
  1842 
  1843 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1844 Requires zChaff with proof generation to be installed.  See
  1845 HOL/ex/SAT_Examples.thy for examples.
  1846 
  1847 * Datatype induction via method 'induct' now preserves the name of the
  1848 induction variable. For example, when proving P(xs::'a list) by
  1849 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1850 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1851 in unstructured proof scripts.
  1852 
  1853 * Reworked implementation of records.  Improved scalability for
  1854 records with many fields, avoiding performance problems for type
  1855 inference. Records are no longer composed of nested field types, but
  1856 of nested extension types. Therefore the record type only grows linear
  1857 in the number of extensions and not in the number of fields.  The
  1858 top-level (users) view on records is preserved.  Potential
  1859 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1860 old record representation. The type generated for a record is called
  1861 <record_name>_ext_type.
  1862 
  1863 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1864 proofs triggered by a record definition or a simproc (if
  1865 quick_and_dirty is enabled).  Definitions of large records can take
  1866 quite long.
  1867 
  1868 New simproc record_upd_simproc for simplification of multiple record
  1869 updates enabled by default.  Moreover, trivial updates are also
  1870 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1871 occasionally, since simplification is more powerful by default.
  1872 
  1873 * typedef: proper support for polymorphic sets, which contain extra
  1874 type-variables in the term.
  1875 
  1876 * Simplifier: automatically reasons about transitivity chains
  1877 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1878 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1879 old proofs break occasionally as simplification may now solve more
  1880 goals than previously.
  1881 
  1882 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1883 present.  Works for all partial orders (class "order"), in particular
  1884 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1885 just like y <= x.
  1886 
  1887 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1888 bound variable or a constant then the let is unfolded.  Otherwise
  1889 first a is simplified to b, and then f b is simplified to g. If
  1890 possible we abstract b from g arriving at "let x = b in h x",
  1891 otherwise we unfold the let and arrive at g.  The simproc can be
  1892 enabled/disabled by the reference use_let_simproc.  Potential
  1893 INCOMPATIBILITY since simplification is more powerful by default.
  1894 
  1895 * Classical reasoning: the meson method now accepts theorems as arguments.
  1896 
  1897 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1898 jobs to provide advice on the provability of subgoals.
  1899 
  1900 * Theory OrderedGroup and Ring_and_Field: various additions and
  1901 improvements to faciliate calculations involving equalities and
  1902 inequalities.
  1903 
  1904 The following theorems have been eliminated or modified
  1905 (INCOMPATIBILITY):
  1906 
  1907   abs_eq             now named abs_of_nonneg
  1908   abs_of_ge_0        now named abs_of_nonneg
  1909   abs_minus_eq       now named abs_of_nonpos
  1910   imp_abs_id         now named abs_of_nonneg
  1911   imp_abs_neg_id     now named abs_of_nonpos
  1912   mult_pos           now named mult_pos_pos
  1913   mult_pos_le        now named mult_nonneg_nonneg
  1914   mult_pos_neg_le    now named mult_nonneg_nonpos
  1915   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1916   mult_neg           now named mult_neg_neg
  1917   mult_neg_le        now named mult_nonpos_nonpos
  1918 
  1919 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1920      
  1921      zero_le_square
  1922      not_square_less_zero 
  1923 
  1924   The following lemmas have been deleted from Real/RealPow:
  1925   
  1926      realpow_zero_zero
  1927      realpow_two
  1928      realpow_less
  1929      zero_le_power
  1930      realpow_two_le
  1931      abs_realpow_two
  1932      realpow_two_abs     
  1933 
  1934 * Theory Parity: added rules for simplifying exponents.
  1935 
  1936 * Theory List:
  1937 
  1938 The following theorems have been eliminated or modified
  1939 (INCOMPATIBILITY):
  1940 
  1941   list_all_Nil       now named list_all.simps(1)
  1942   list_all_Cons      now named list_all.simps(2)
  1943   list_all_conv      now named list_all_iff
  1944   set_mem_eq         now named mem_iff
  1945 
  1946 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1947 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1948 
  1949 
  1950 *** HOL-Complex ***
  1951 
  1952 * Theory RealDef: better support for embedding natural numbers and
  1953 integers in the reals.
  1954 
  1955 The following theorems have been eliminated or modified
  1956 (INCOMPATIBILITY):
  1957 
  1958   exp_ge_add_one_self  now requires no hypotheses
  1959   real_of_int_add      reversed direction of equality (use [symmetric])
  1960   real_of_int_minus    reversed direction of equality (use [symmetric])
  1961   real_of_int_diff     reversed direction of equality (use [symmetric])
  1962   real_of_int_mult     reversed direction of equality (use [symmetric])
  1963 
  1964 * Theory RComplete: expanded support for floor and ceiling functions.
  1965 
  1966 * Theory Ln is new, with properties of the natural logarithm
  1967 
  1968 * Hyperreal: There is a new type constructor "star" for making
  1969 nonstandard types.  The old type names are now type synonyms:
  1970 
  1971   hypreal = real star
  1972   hypnat = nat star
  1973   hcomplex = complex star
  1974 
  1975 * Hyperreal: Many groups of similarly-defined constants have been
  1976 replaced by polymorphic versions (INCOMPATIBILITY):
  1977 
  1978   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1979 
  1980   starset      <-- starsetNat, starsetC
  1981   *s*          <-- *sNat*, *sc*
  1982   starset_n    <-- starsetNat_n, starsetC_n
  1983   *sn*         <-- *sNatn*, *scn*
  1984   InternalSets <-- InternalNatSets, InternalCSets
  1985 
  1986   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1987   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1988   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1989   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1990   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1991 
  1992 * Hyperreal: Many type-specific theorems have been removed in favor of
  1993 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1994 
  1995   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1996   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1997   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1998   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1999   right_minus <-- hypreal_add_minus
  2000   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2001   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2002   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2003   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2004   mult_1_right <-- hcomplex_mult_one_right
  2005   mult_zero_left <-- hcomplex_mult_zero_left
  2006   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2007   right_distrib <-- hypnat_add_mult_distrib2
  2008   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2009   right_inverse <-- hypreal_mult_inverse
  2010   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2011   order_refl <-- {hypreal,hypnat}_le_refl
  2012   order_trans <-- {hypreal,hypnat}_le_trans
  2013   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2014   order_less_le <-- {hypreal,hypnat}_less_le
  2015   linorder_linear <-- {hypreal,hypnat}_le_linear
  2016   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2017   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2018   add_nonneg_nonneg <-- hypreal_le_add_order
  2019 
  2020 * Hyperreal: Separate theorems having to do with type-specific
  2021 versions of constants have been merged into theorems that apply to the
  2022 new polymorphic constants (INCOMPATIBILITY):
  2023 
  2024   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2025   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2026   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2027   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2028   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2029   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2030   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2031   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2032   STAR_diff <-- {STAR,STARC}_diff
  2033   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2034     STARC_hcomplex_of_complex}_image_subset
  2035   starset_n_Un <-- starset{Nat,C}_n_Un
  2036   starset_n_Int <-- starset{Nat,C}_n_Int
  2037   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2038   starset_n_diff <-- starset{Nat,C}_n_diff
  2039   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2040   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2041   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2042   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2043   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2044   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2045   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2046   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2047   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2048   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2049   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2050   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2051   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2052   starfun_diff <-- starfun{C,RC,CR}_diff
  2053   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2054   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2055   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2056   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2057   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2058   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2059   starfun_Id <-- starfunC_Id
  2060   starfun_approx <-- starfun{Nat,CR}_approx
  2061   starfun_capprox <-- starfun{C,RC}_capprox
  2062   starfun_abs <-- starfunNat_rabs
  2063   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2064   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2065   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2066   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2067   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2068   starfun_add_approx <-- starfunCR_add_approx
  2069   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2070   starfun_divide <-- starfun{C,CR,RC}_divide
  2071   starfun_n <-- starfun{Nat,C}_n
  2072   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2073   starfun_n_add <-- starfun{Nat,C}_n_add
  2074   starfun_n_add_minus <-- starfunNat_n_add_minus
  2075   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2076   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2077   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2078 
  2079   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2080   star_n_minus <-- {hypreal,hcomplex}_minus
  2081   star_n_diff <-- {hypreal,hcomplex}_diff
  2082   star_n_mult <-- {hypreal,hcomplex}_mult
  2083   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2084   star_n_le <-- {hypreal,hypnat}_le
  2085   star_n_less <-- {hypreal,hypnat}_less
  2086   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2087   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2088   star_n_abs <-- hypreal_hrabs
  2089   star_n_divide <-- hcomplex_divide
  2090 
  2091   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2092   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2093   star_of_diff <-- hypreal_of_real_diff
  2094   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2095   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2096   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2097   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2098   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2099   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2100   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2101   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2102   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2103   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2104   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2105   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2106   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2107   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2108   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2109   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2110   star_of_power <-- hypreal_of_real_power
  2111   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2112 
  2113 * Hyperreal: new method "transfer" that implements the transfer
  2114 principle of nonstandard analysis. With a subgoal that mentions
  2115 nonstandard types like "'a star", the command "apply transfer"
  2116 replaces it with an equivalent one that mentions only standard types.
  2117 To be successful, all free variables must have standard types; non-
  2118 standard variables must have explicit universal quantifiers.
  2119 
  2120 * Hyperreal: A theory of Taylor series.
  2121 
  2122 
  2123 *** HOLCF ***
  2124 
  2125 * Discontinued special version of 'constdefs' (which used to support
  2126 continuous functions) in favor of the general Pure one with full
  2127 type-inference.
  2128 
  2129 * New simplification procedure for solving continuity conditions; it
  2130 is much faster on terms with many nested lambda abstractions (cubic
  2131 instead of exponential time).
  2132 
  2133 * New syntax for domain package: selector names are now optional.
  2134 Parentheses should be omitted unless argument is lazy, for example:
  2135 
  2136   domain 'a stream = cons "'a" (lazy "'a stream")
  2137 
  2138 * New command 'fixrec' for defining recursive functions with pattern
  2139 matching; defining multiple functions with mutual recursion is also
  2140 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2141 sinr, or any data constructor defined by the domain package. The given
  2142 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2143 syntax and examples.
  2144 
  2145 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2146 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2147 but the proof obligation additionally includes an admissibility
  2148 requirement. The packages generate instances of class cpo or pcpo,
  2149 with continuity and strictness theorems for Rep and Abs.
  2150 
  2151 * HOLCF: Many theorems have been renamed according to a more standard naming
  2152 scheme (INCOMPATIBILITY):
  2153 
  2154   foo_inject:  "foo$x = foo$y ==> x = y"
  2155   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2156   foo_less:    "(foo$x << foo$y) = (x << y)"
  2157   foo_strict:  "foo$UU = UU"
  2158   foo_defined: "... ==> foo$x ~= UU"
  2159   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2160 
  2161 
  2162 *** ZF ***
  2163 
  2164 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2165 including the First Isomorphism Theorem (on quotienting by the kernel
  2166 of a homomorphism).
  2167 
  2168 * ZF/Simplifier: install second copy of type solver that actually
  2169 makes use of TC rules declared to Isar proof contexts (or locales);
  2170 the old version is still required for ML proof scripts.
  2171 
  2172 
  2173 *** Cube ***
  2174 
  2175 * Converted to Isar theory format; use locales instead of axiomatic
  2176 theories.
  2177 
  2178 
  2179 *** ML ***
  2180 
  2181 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2182 for ||>, ||>>, |>>,
  2183 
  2184 * Pure/library.ML no longer defines its own option datatype, but uses
  2185 that of the SML basis, which has constructors NONE and SOME instead of
  2186 None and Some, as well as exception Option.Option instead of OPTION.
  2187 The functions the, if_none, is_some, is_none have been adapted
  2188 accordingly, while Option.map replaces apsome.
  2189 
  2190 * Pure/library.ML: the exception LIST has been given up in favour of
  2191 the standard exceptions Empty and Subscript, as well as
  2192 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2193 superceded by the standard hd and tl functions etc.
  2194 
  2195 A number of basic list functions are no longer exported to the ML
  2196 toplevel, as they are variants of predefined functions.  The following
  2197 suggests how one can translate existing code:
  2198 
  2199     rev_append xs ys = List.revAppend (xs, ys)
  2200     nth_elem (i, xs) = List.nth (xs, i)
  2201     last_elem xs = List.last xs
  2202     flat xss = List.concat xss
  2203     seq fs = List.app fs
  2204     partition P xs = List.partition P xs
  2205     mapfilter f xs = List.mapPartial f xs
  2206 
  2207 * Pure/library.ML: several combinators for linear functional
  2208 transformations, notably reverse application and composition:
  2209 
  2210   x |> f                f #> g
  2211   (x, y) |-> f          f #-> g
  2212 
  2213 * Pure/library.ML: introduced/changed precedence of infix operators:
  2214 
  2215   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2216   infix 2 ?;
  2217   infix 3 o oo ooo oooo;
  2218   infix 4 ~~ upto downto;
  2219 
  2220 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2221 infix operators.
  2222 
  2223 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2224 fold_map support linear functional transformations and nesting.  For
  2225 example:
  2226 
  2227   fold f [x1, ..., xN] y =
  2228     y |> f x1 |> ... |> f xN
  2229 
  2230   (fold o fold) f [xs1, ..., xsN] y =
  2231     y |> fold f xs1 |> ... |> fold f xsN
  2232 
  2233   fold f [x1, ..., xN] =
  2234     f x1 #> ... #> f xN
  2235 
  2236   (fold o fold) f [xs1, ..., xsN] =
  2237     fold f xs1 #> ... #> fold f xsN
  2238 
  2239 * Pure/library.ML: the following selectors on type 'a option are
  2240 available:
  2241 
  2242   the:               'a option -> 'a  (*partial*)
  2243   these:             'a option -> 'a  where 'a = 'b list
  2244   the_default: 'a -> 'a option -> 'a
  2245   the_list:          'a option -> 'a list
  2246 
  2247 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2248 basic operations for association lists, following natural argument
  2249 order; moreover the explicit equality predicate passed here avoids
  2250 potentially expensive polymorphic runtime equality checks.
  2251 The old functions may be expressed as follows:
  2252 
  2253   assoc = uncurry (AList.lookup (op =))
  2254   assocs = these oo AList.lookup (op =)
  2255   overwrite = uncurry (AList.update (op =)) o swap
  2256 
  2257 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2258 
  2259   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2260   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2261 
  2262 replacing make_keylist and keyfilter (occassionally used)
  2263 Naive rewrites:
  2264 
  2265   make_keylist = AList.make
  2266   keyfilter = AList.find (op =)
  2267 
  2268 * eq_fst and eq_snd now take explicit equality parameter, thus
  2269   avoiding eqtypes. Naive rewrites:
  2270 
  2271     eq_fst = eq_fst (op =)
  2272     eq_snd = eq_snd (op =)
  2273 
  2274 * Removed deprecated apl and apr (rarely used).
  2275   Naive rewrites:
  2276 
  2277     apl (n, op) =>>= curry op n
  2278     apr (op, m) =>>= fn n => op (n, m)
  2279 
  2280 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2281 provides a reasonably efficient light-weight implementation of sets as
  2282 lists.
  2283 
  2284 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2285 few new operations; existing lookup and update are now curried to
  2286 follow natural argument order (for use with fold etc.);
  2287 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2288 
  2289 * Pure/General: output via the Isabelle channels of
  2290 writeln/warning/error etc. is now passed through Output.output, with a
  2291 hook for arbitrary transformations depending on the print_mode
  2292 (cf. Output.add_mode -- the first active mode that provides a output
  2293 function wins).  Already formatted output may be embedded into further
  2294 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2295 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2296 accommodate easy composition of diagnostic messages etc.  Programmers
  2297 rarely need to care about Output.output or Output.raw at all, with
  2298 some notable exceptions: Output.output is required when bypassing the
  2299 standard channels (writeln etc.), or in token translations to produce
  2300 properly formatted results; Output.raw is required when capturing
  2301 already output material that will eventually be presented to the user
  2302 a second time.  For the default print mode, both Output.output and
  2303 Output.raw have no effect.
  2304 
  2305 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2306 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2307 cumulative results are displayed at the end of a batch session.
  2308 
  2309 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2310 replaced by File.platform_path and File.shell_path (with appropriate
  2311 hooks).  This provides a clean interface for unusual systems where the
  2312 internal and external process view of file names are different.
  2313 
  2314 * Pure: more efficient orders for basic syntactic entities: added
  2315 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2316 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2317 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2318 orders now -- potential INCOMPATIBILITY for code that depends on a
  2319 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2320 Library.sort_strings on result).
  2321 
  2322 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2323 fold_types traverse types/terms from left to right, observing natural
  2324 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2325 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2326 
  2327 * Pure: name spaces have been refined, with significant changes of the
  2328 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2329 to extern(_table).  The plain name entry path is superceded by a
  2330 general 'naming' context, which also includes the 'policy' to produce
  2331 a fully qualified name and external accesses of a fully qualified
  2332 name; NameSpace.extend is superceded by context dependent
  2333 Sign.declare_name.  Several theory and proof context operations modify
  2334 the naming context.  Especially note Theory.restore_naming and
  2335 ProofContext.restore_naming to get back to a sane state; note that
  2336 Theory.add_path is no longer sufficient to recover from
  2337 Theory.absolute_path in particular.
  2338 
  2339 * Pure: new flags short_names (default false) and unique_names
  2340 (default true) for controlling output of qualified names.  If
  2341 short_names is set, names are printed unqualified.  If unique_names is
  2342 reset, the name prefix is reduced to the minimum required to achieve
  2343 the original result when interning again, even if there is an overlap
  2344 with earlier declarations.
  2345 
  2346 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2347 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2348 (useful for printing error messages).  INCOMPATIBILITY.
  2349 
  2350 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2351 Theory.theory are now identified, referring to the universal
  2352 Context.theory (see Pure/context.ML).  Actual signature and theory
  2353 content is managed as theory data.  The old code and interfaces were
  2354 spread over many files and structures; the new arrangement introduces
  2355 considerable INCOMPATIBILITY to gain more clarity:
  2356 
  2357   Context -- theory management operations (name, identity, inclusion,
  2358     parents, ancestors, merge, etc.), plus generic theory data;
  2359 
  2360   Sign -- logical signature and syntax operations (declaring consts,
  2361     types, etc.), plus certify/read for common entities;
  2362 
  2363   Theory -- logical theory operations (stating axioms, definitions,
  2364     oracles), plus a copy of logical signature operations (consts,
  2365     types, etc.); also a few basic management operations (Theory.copy,
  2366     Theory.merge, etc.)
  2367 
  2368 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2369 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2370 for convenience -- they merely return the theory.
  2371 
  2372 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2373 
  2374 * Pure: the Isar proof context type is already defined early in Pure
  2375 as Context.proof (note that ProofContext.context and Proof.context are
  2376 aliases, where the latter is the preferred name).  This enables other
  2377 Isabelle components to refer to that type even before Isar is present.
  2378 
  2379 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2380 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2381 any of these kinds.  For example, Sign.intern typeK is now
  2382 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2383 Theory.hide_types.  Also note that former
  2384 Theory.hide_classes/types/consts are now
  2385 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2386 internalize their arguments!  INCOMPATIBILITY.
  2387 
  2388 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2389 datatype thmref (with constructors Name and NameSelection) instead of
  2390 plain string -- INCOMPATIBILITY;
  2391 
  2392 * Pure: cases produced by proof methods specify options, where NONE
  2393 means to remove case bindings -- INCOMPATIBILITY in
  2394 (RAW_)METHOD_CASES.
  2395 
  2396 * Pure: the following operations retrieve axioms or theorems from a
  2397 theory node or theory hierarchy, respectively:
  2398 
  2399   Theory.axioms_of: theory -> (string * term) list
  2400   Theory.all_axioms_of: theory -> (string * term) list
  2401   PureThy.thms_of: theory -> (string * thm) list
  2402   PureThy.all_thms_of: theory -> (string * thm) list
  2403 
  2404 * Pure: print_tac now outputs the goal through the trace channel.
  2405 
  2406 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2407 Reference Toplevel.debug (default false) controls detailed printing
  2408 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2409 controls execution profiling -- set to 1 for time and 2 for space
  2410 (both increase the runtime).
  2411 
  2412 * Isar session: The initial use of ROOT.ML is now always timed,
  2413 i.e. the log will show the actual process times, in contrast to the
  2414 elapsed wall-clock time that the outer shell wrapper produces.
  2415 
  2416 * Simplifier: improved handling of bound variables (nameless
  2417 representation, avoid allocating new strings).  Simprocs that invoke
  2418 the Simplifier recursively should use Simplifier.inherit_bounds to
  2419 avoid local name clashes.  Failure to do so produces warnings
  2420 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2421 for further details.
  2422 
  2423 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2424 bindings for all theorems stored within a given theory; this may help
  2425 in porting non-Isar theories to Isar ones, while keeping ML proof
  2426 scripts for the time being.
  2427 
  2428 * ML operator HTML.with_charset specifies the charset begin used for
  2429 generated HTML files.  For example:
  2430 
  2431   HTML.with_charset "utf-8" use_thy "Hebrew";
  2432   HTML.with_charset "utf-8" use_thy "Chinese";
  2433 
  2434 
  2435 *** System ***
  2436 
  2437 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2438 isabelle, isatool etc.).
  2439 
  2440 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2441 isatool doc, isatool mkdir, display_drafts etc.).
  2442 
  2443 * isatool usedir: option -f allows specification of the ML file to be
  2444 used by Isabelle; default is ROOT.ML.
  2445 
  2446 * New isatool version outputs the version identifier of the Isabelle
  2447 distribution being used.
  2448 
  2449 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2450 (containing Boolean satisfiability problems) into Isabelle/HOL
  2451 theories.
  2452 
  2453 
  2454 
  2455 New in Isabelle2004 (April 2004)
  2456 --------------------------------
  2457 
  2458 *** General ***
  2459 
  2460 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2461   Replaces linorder.ML.
  2462 
  2463 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2464   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2465   (\<a>...\<z>), are now considered normal letters, and can therefore
  2466   be used anywhere where an ASCII letter (a...zA...Z) has until
  2467   now. COMPATIBILITY: This obviously changes the parsing of some
  2468   terms, especially where a symbol has been used as a binder, say
  2469   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2470   as an identifier.  Fix it by inserting a space around former
  2471   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2472   existing theory and ML files.
  2473 
  2474 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2475 
  2476 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2477   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2478   a normal (but invisible) letter. For multiple letter subscripts repeat
  2479   \<^isub> like this: x\<^isub>1\<^isub>2.
  2480 
  2481 * Pure: There are now sub-/superscripts that can span more than one
  2482   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2483   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2484   superscript. The new control characters are not identifier parts.
  2485 
  2486 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2487   content of "..." to the latex file instead of \isacntrl... . The "..."
  2488   may consist of any printable characters excluding the end bracket >.
  2489 
  2490 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2491   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2492   declare constants "final", which prevents their being given a definition
  2493   later.  It is useful for constants whose behaviour is fixed axiomatically
  2494   rather than definitionally, such as the meta-logic connectives.
  2495 
  2496 * Pure: 'instance' now handles general arities with general sorts
  2497   (i.e. intersections of classes),
  2498 
  2499 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2500   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2501   It can be changed to alter the colors/layout of generated pages.
  2502 
  2503 
  2504 *** Isar ***
  2505 
  2506 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2507   cut_tac, subgoal_tac and thin_tac:
  2508   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2509     locales are no longer forced to write Isar proof scripts.
  2510     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2511     emulations.
  2512   - INCOMPATIBILITY: names of variables to be instantiated may no
  2513     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2514     This is consistent with the instantiation attribute "where".
  2515 
  2516 * Attributes "where" and "of":
  2517   - Now take type variables of instantiated theorem into account when reading
  2518     the instantiation string.  This fixes a bug that caused instantiated
  2519     theorems to have too special types in some circumstances.
  2520   - "where" permits explicit instantiations of type variables.
  2521 
  2522 * Calculation commands "moreover" and "also" no longer interfere with
  2523   current facts ("this"), admitting arbitrary combinations with "then"
  2524   and derived forms.
  2525 
  2526 * Locales:
  2527   - Goal statements involving the context element "includes" no longer
  2528     generate theorems with internal delta predicates (those ending on
  2529     "_axioms") in the premise.
  2530     Resolve particular premise with <locale>.intro to obtain old form.
  2531   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2532     specification and "includes" elements in goal statement.
  2533   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2534     [intro?] and [elim?] (respectively) by default.
  2535   - Experimental command for instantiation of locales in proof contexts:
  2536         instantiate <label>[<attrs>]: <loc>
  2537     Instantiates locale <loc> and adds all its theorems to the current context
  2538     taking into account their attributes.  Label and attrs are optional
  2539     modifiers, like in theorem declarations.  If present, names of
  2540     instantiated theorems are qualified with <label>, and the attributes
  2541     <attrs> are applied after any attributes these theorems might have already.
  2542       If the locale has assumptions, a chained fact of the form
  2543     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2544     are derived.  The command does not support old-style locales declared
  2545     with "locale (open)".
  2546       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2547 
  2548 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2549   (Isar) contexts.
  2550 
  2551 
  2552 *** HOL ***
  2553 
  2554 * Proof import: new image HOL4 contains the imported library from
  2555   the HOL4 system with about 2500 theorems. It is imported by
  2556   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2557   can be used like any other Isabelle image.  See
  2558   HOL/Import/HOL/README for more information.
  2559 
  2560 * Simplifier:
  2561   - Much improved handling of linear and partial orders.
  2562     Reasoners for linear and partial orders are set up for type classes
  2563     "linorder" and "order" respectively, and are added to the default simpset
  2564     as solvers.  This means that the simplifier can build transitivity chains
  2565     to solve goals from the assumptions.
  2566   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2567     of blast or auto after simplification become unnecessary because the goal
  2568     is solved by simplification already.
  2569 
  2570 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2571     all proved in axiomatic type classes for semirings, rings and fields.
  2572 
  2573 * Numerics:
  2574   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2575     now formalized using the Ring_and_Field theory mentioned above.
  2576   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2577     than before, because now they are set up once in a generic manner.
  2578   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2579     Look for the general versions in Ring_and_Field (and Power if they concern
  2580     exponentiation).
  2581 
  2582 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2583 
  2584 * Records:
  2585   - Record types are now by default printed with their type abbreviation
  2586     instead of the list of all field types. This can be configured via
  2587     the reference "print_record_type_abbr".
  2588   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2589     (not enabled by default).
  2590   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2591     EX x. x = sel r to True (not enabled by default).
  2592   - Tactic "record_split_simp_tac" to split and simplify records added.
  2593 
  2594 * 'specification' command added, allowing for definition by
  2595   specification.  There is also an 'ax_specification' command that
  2596   introduces the new constants axiomatically.
  2597 
  2598 * arith(_tac) is now able to generate counterexamples for reals as well.
  2599 
  2600 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2601 
  2602 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2603   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2604 
  2605 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2606   matrix theory to linear programming.
  2607 
  2608 * Unions and Intersections:
  2609   The latex output syntax of UN and INT has been changed
  2610   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2611   i.e. the index formulae has become a subscript.
  2612   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2613 
  2614 * Unions and Intersections over Intervals:
  2615   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2616   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2617   like in normal math, and corresponding versions for < and for intersection.
  2618 
  2619 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2620   lexicographic dictonary ordering has been added as "lexord".
  2621 
  2622 * ML: the legacy theory structures Int and List have been removed. They had
  2623   conflicted with ML Basis Library structures having the same names.
  2624 
  2625 * 'refute' command added to search for (finite) countermodels.  Only works
  2626   for a fragment of HOL.  The installation of an external SAT solver is
  2627   highly recommended.  See "HOL/Refute.thy" for details.
  2628 
  2629 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2630   formulae under an assignment of free variables to random values.
  2631   In contrast to 'refute', it can deal with inductive datatypes,
  2632   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2633   for examples.
  2634 
  2635 
  2636 *** HOLCF ***
  2637 
  2638 * Streams now come with concatenation and are part of the HOLCF image
  2639 
  2640 
  2641 
  2642 New in Isabelle2003 (May 2003)
  2643 ------------------------------
  2644 
  2645 *** General ***
  2646 
  2647 * Provers/simplifier:
  2648 
  2649   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2650     Assumptions are now subject to complete mutual simplification,
  2651     not just from left to right. The simplifier now preserves
  2652     the order of assumptions.
  2653 
  2654     Potential INCOMPATIBILITY:
  2655 
  2656     -- simp sometimes diverges where the old version did
  2657        not, e.g. invoking simp on the goal
  2658 
  2659         [| P (f x); y = x; f x = f y |] ==> Q
  2660 
  2661        now gives rise to the infinite reduction sequence
  2662 
  2663         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2664 
  2665        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2666        kind of problem.
  2667 
  2668     -- Tactics combining classical reasoner and simplification (such as auto)
  2669        are also affected by this change, because many of them rely on
  2670        simp. They may sometimes diverge as well or yield a different numbers
  2671        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2672        in case of problems. Sometimes subsequent calls to the classical
  2673        reasoner will fail because a preceeding call to the simplifier too
  2674        eagerly simplified the goal, e.g. deleted redundant premises.
  2675 
  2676   - The simplifier trace now shows the names of the applied rewrite rules
  2677 
  2678   - You can limit the number of recursive invocations of the simplifier
  2679     during conditional rewriting (where the simplifie tries to solve the
  2680     conditions before applying the rewrite rule):
  2681     ML "simp_depth_limit := n"
  2682     where n is an integer. Thus you can force termination where previously
  2683     the simplifier would diverge.
  2684 
  2685   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2686 
  2687   - No longer aborts on failed congruence proof.  Instead, the
  2688     congruence is ignored.
  2689 
  2690 * Pure: New generic framework for extracting programs from constructive
  2691   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2692   as HOL/Extraction for some case studies.
  2693 
  2694 * Pure: The main goal of the proof state is no longer shown by default, only
  2695 the subgoals. This behaviour is controlled by a new flag.
  2696    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2697 (ML: Proof.show_main_goal).
  2698 
  2699 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2700 rules whose conclusion matches subgoal 1:
  2701       PG menu: Isabelle/Isar -> Show me -> matching rules
  2702 The rules are ordered by how closely they match the subgoal.
  2703 In particular, rules that solve a subgoal outright are displayed first
  2704 (or rather last, the way they are printed).
  2705 (ML: ProofGeneral.print_intros())
  2706 
  2707 * Pure: New flag trace_unify_fail causes unification to print
  2708 diagnostic information (PG: in trace buffer) when it fails. This is
  2709 useful for figuring out why single step proofs like rule, erule or
  2710 assumption failed.
  2711 
  2712 * Pure: Locale specifications now produce predicate definitions
  2713 according to the body of text (covering assumptions modulo local
  2714 definitions); predicate "loc_axioms" covers newly introduced text,
  2715 while "loc" is cumulative wrt. all included locale expressions; the
  2716 latter view is presented only on export into the global theory
  2717 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2718 on the old view without predicates;
  2719 
  2720 * Pure: predefined locales "var" and "struct" are useful for sharing
  2721 parameters (as in CASL, for example); just specify something like
  2722 ``var x + var y + struct M'' as import;
  2723 
  2724 * Pure: improved thms_containing: proper indexing of facts instead of
  2725 raw theorems; check validity of results wrt. current name space;
  2726 include local facts of proof configuration (also covers active
  2727 locales), cover fixed variables in index; may use "_" in term
  2728 specification; an optional limit for the number of printed facts may
  2729 be given (the default is 40);
  2730 
  2731 * Pure: disallow duplicate fact bindings within new-style theory files
  2732 (batch-mode only);
  2733 
  2734 * Provers: improved induct method: assumptions introduced by case
  2735 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2736 the goal statement); "foo" still refers to all facts collectively;
  2737 
  2738 * Provers: the function blast.overloaded has been removed: all constants
  2739 are regarded as potentially overloaded, which improves robustness in exchange
  2740 for slight decrease in efficiency;
  2741 
  2742 * Provers/linorder: New generic prover for transitivity reasoning over
  2743 linear orders.  Note: this prover is not efficient!
  2744 
  2745 * Isar: preview of problems to finish 'show' now produce an error
  2746 rather than just a warning (in interactive mode);
  2747 
  2748 
  2749 *** HOL ***
  2750 
  2751 * arith(_tac)
  2752 
  2753  - Produces a counter example if it cannot prove a goal.
  2754    Note that the counter example may be spurious if the goal is not a formula
  2755    of quantifier-free linear arithmetic.
  2756    In ProofGeneral the counter example appears in the trace buffer.
  2757 
  2758  - Knows about div k and mod k where k is a numeral of type nat or int.
  2759 
  2760  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2761    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2762    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2763 
  2764 * simp's arithmetic capabilities have been enhanced a bit: it now
  2765 takes ~= in premises into account (by performing a case split);
  2766 
  2767 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2768 are distributed over a sum of terms;
  2769 
  2770 * New tactic "trans_tac" and method "trans" instantiate
  2771 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2772 "<=", "<" and "=").
  2773 
  2774 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2775 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2776 
  2777 * 'typedef' command has new option "open" to suppress the set
  2778 definition;
  2779 
  2780 * functions Min and Max on finite sets have been introduced (theory
  2781 Finite_Set);
  2782 
  2783 * attribute [symmetric] now works for relations as well; it turns
  2784 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2785 
  2786 * induct over a !!-quantified statement (say !!x1..xn):
  2787   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2788 
  2789 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2790 %x. None. Warning: empty_def now refers to the previously hidden definition
  2791 of the empty set.
  2792 
  2793 * Algebra: formalization of classical algebra.  Intended as base for
  2794 any algebraic development in Isabelle.  Currently covers group theory
  2795 (up to Sylow's theorem) and ring theory (Universal Property of
  2796 Univariate Polynomials).  Contributions welcome;
  2797 
  2798 * GroupTheory: deleted, since its material has been moved to Algebra;
  2799 
  2800 * Complex: new directory of the complex numbers with numeric constants,
  2801 nonstandard complex numbers, and some complex analysis, standard and
  2802 nonstandard (Jacques Fleuriot);
  2803 
  2804 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2805 
  2806 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2807 Fleuriot);
  2808 
  2809 * Real/HahnBanach: updated and adapted to locales;
  2810 
  2811 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2812 Gray and Kramer);
  2813 
  2814 * UNITY: added the Meier-Sanders theory of progress sets;
  2815 
  2816 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2817 as abstract algorithms, instantiated to the JVM;
  2818 
  2819 * Bali: Java source language formalization. Type system, operational
  2820 semantics, axiomatic semantics. Supported language features:
  2821 classes, interfaces, objects,virtual methods, static methods,
  2822 static/instance fields, arrays, access modifiers, definite
  2823 assignment, exceptions.
  2824 
  2825 
  2826 *** ZF ***
  2827 
  2828 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2829 universe, etc.);
  2830 
  2831 * Main ZF: virtually all theories converted to new-style format;
  2832 
  2833 
  2834 *** ML ***
  2835 
  2836 * Pure: Tactic.prove provides sane interface for internal proofs;
  2837 omits the infamous "standard" operation, so this is more appropriate
  2838 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2839 
  2840 * Pure: improved error reporting of simprocs;
  2841 
  2842 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2843 up simprocs;
  2844 
  2845 
  2846 *** Document preparation ***
  2847 
  2848 * uses \par instead of \\ for line breaks in theory text. This may
  2849 shift some page breaks in large documents. To get the old behaviour
  2850 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2851 
  2852 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2853 other packages
  2854 
  2855 * \<euro> now needs package babel/greek instead of marvosym (which
  2856 broke \Rightarrow)
  2857 
  2858 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2859 textcomp package)
  2860 
  2861 
  2862 
  2863 New in Isabelle2002 (March 2002)
  2864 --------------------------------
  2865 
  2866 *** Document preparation ***
  2867 
  2868 * greatly simplified document preparation setup, including more
  2869 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2870 instructive isatool mkdir; users should basically be able to get
  2871 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2872 users may run a separate document processing stage manually like this:
  2873 "isatool usedir -D output HOL Test && isatool document Test/output";
  2874 
  2875 * theory dependency graph may now be incorporated into documents;
  2876 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2877 with \includegraphics of LaTeX;
  2878 
  2879 * proper spacing of consecutive markup elements, especially text
  2880 blocks after section headings;
  2881 
  2882 * support bold style (for single symbols only), input syntax is like
  2883 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2884 
  2885 * \<bullet> is now output as bold \cdot by default, which looks much
  2886 better in printed text;
  2887 
  2888 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2889 note that these symbols are currently unavailable in Proof General /
  2890 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2891 
  2892 * isatool latex no longer depends on changed TEXINPUTS, instead
  2893 isatool document copies the Isabelle style files to the target
  2894 location;
  2895 
  2896 
  2897 *** Isar ***
  2898 
  2899 * Pure/Provers: improved proof by cases and induction;
  2900   - 'case' command admits impromptu naming of parameters (such as
  2901     "case (Suc n)");
  2902   - 'induct' method divinates rule instantiation from the inductive
  2903     claim; no longer requires excessive ?P bindings for proper
  2904     instantiation of cases;
  2905   - 'induct' method properly enumerates all possibilities of set/type
  2906     rules; as a consequence facts may be also passed through *type*
  2907     rules without further ado;
  2908   - 'induct' method now derives symbolic cases from the *rulified*
  2909     rule (before it used to rulify cases stemming from the internal
  2910     atomized version); this means that the context of a non-atomic
  2911     statement becomes is included in the hypothesis, avoiding the
  2912     slightly cumbersome show "PROP ?case" form;
  2913   - 'induct' may now use elim-style induction rules without chaining
  2914     facts, using ``missing'' premises from the goal state; this allows
  2915     rules stemming from inductive sets to be applied in unstructured
  2916     scripts, while still benefitting from proper handling of non-atomic
  2917     statements; NB: major inductive premises need to be put first, all
  2918     the rest of the goal is passed through the induction;
  2919   - 'induct' proper support for mutual induction involving non-atomic
  2920     rule statements (uses the new concept of simultaneous goals, see
  2921     below);
  2922   - append all possible rule selections, but only use the first
  2923     success (no backtracking);
  2924   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2925   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2926   - added 'print_induct_rules' (covered by help item in recent Proof
  2927     General versions);
  2928   - moved induct/cases attributes to Pure, methods to Provers;
  2929   - generic method setup instantiated for FOL and HOL;
  2930 
  2931 * Pure: support multiple simultaneous goal statements, for example
  2932 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2933 meta-level mechanism, this acts as if several individual goals had
  2934 been stated separately; in particular common proof methods need to be
  2935 repeated in order to cover all claims; note that a single elimination
  2936 step is *not* sufficient to establish the two conjunctions, so this
  2937 fails:
  2938 
  2939   assume "A & B" then have A and B ..   (*".." fails*)
  2940 
  2941 better use "obtain" in situations as above; alternative refer to
  2942 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2943 
  2944 * Pure: proper integration with ``locales''; unlike the original
  2945 version by Florian Kammller, Isar locales package high-level proof
  2946 contexts rather than raw logical ones (e.g. we admit to include
  2947 attributes everywhere); operations on locales include merge and
  2948 rename; support for implicit arguments (``structures''); simultaneous
  2949 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2950 some examples;
  2951 
  2952 * Pure: the following commands have been ``localized'', supporting a
  2953 target locale specification "(in name)": 'lemma', 'theorem',
  2954 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2955 stored both within the locale and at the theory level (exported and
  2956 qualified by the locale name);
  2957 
  2958 * Pure: theory goals may now be specified in ``long'' form, with
  2959 ad-hoc contexts consisting of arbitrary locale elements. for example
  2960 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2961 definitions may be given, too); the result is a meta-level rule with
  2962 the context elements being discharged in the obvious way;
  2963 
  2964 * Pure: new proof command 'using' allows to augment currently used
  2965 facts after a goal statement ('using' is syntactically analogous to
  2966 'apply', but acts on the goal's facts only); this allows chained facts
  2967 to be separated into parts given before and after a claim, as in
  2968 ``from a and b have C using d and e <proof>'';
  2969 
  2970 * Pure: renamed "antecedent" case to "rule_context";
  2971 
  2972 * Pure: new 'judgment' command records explicit information about the
  2973 object-logic embedding (used by several tools internally); no longer
  2974 use hard-wired "Trueprop";
  2975 
  2976 * Pure: added 'corollary' command;
  2977 
  2978 * Pure: fixed 'token_translation' command;
  2979 
  2980 * Pure: removed obsolete 'exported' attribute;
  2981 
  2982 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2983 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2984 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2985 
  2986 * Pure: method 'atomize' presents local goal premises as object-level
  2987 statements (atomic meta-level propositions); setup controlled via
  2988 rewrite rules declarations of 'atomize' attribute; example
  2989 application: 'induct' method with proper rule statements in improper
  2990 proof *scripts*;
  2991 
  2992 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2993 now consider the syntactic context of assumptions, giving a better
  2994 chance to get type-inference of the arguments right (this is
  2995 especially important for locales);
  2996 
  2997 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2998 mode;
  2999 
  3000 * Pure/obtain: the formal conclusion "thesis", being marked as
  3001 ``internal'', may no longer be reference directly in the text;
  3002 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3003 situations;
  3004 
  3005 * Pure: generic 'sym' attribute which declares a rule both as pure
  3006 'elim?' and for the 'symmetric' operation;
  3007 
  3008 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3009 text; the fixed correlation with particular command syntax has been
  3010 discontinued;
  3011 
  3012 * Pure: new method 'rules' is particularly well-suited for proof
  3013 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3014 but often produces more compact proof terms with less detours;
  3015 
  3016 * Pure/Provers/classical: simplified integration with pure rule
  3017 attributes and methods; the classical "intro?/elim?/dest?"
  3018 declarations coincide with the pure ones; the "rule" method no longer
  3019 includes classically swapped intros; "intro" and "elim" methods no
  3020 longer pick rules from the context; also got rid of ML declarations
  3021 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3022 INCOMPATIBILITY;
  3023 
  3024 * Provers/classical: attribute 'swapped' produces classical inversions
  3025 of introduction rules;
  3026 
  3027 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3028 rules instead of full simplifier context; 'iff' attribute handles
  3029 conditional rules;
  3030 
  3031 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3032 
  3033 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3034 "(permissive)" option to recover old behavior;
  3035 
  3036 * HOL: 'inductive' no longer features separate (collective) attributes
  3037 for 'intros' (was found too confusing);
  3038 
  3039 * HOL: properly declared induction rules less_induct and
  3040 wf_induct_rule;
  3041 
  3042 
  3043 *** HOL ***
  3044 
  3045 * HOL: moved over to sane numeral syntax; the new policy is as
  3046 follows:
  3047 
  3048   - 0 and 1 are polymorphic constants, which are defined on any
  3049   numeric type (nat, int, real etc.);
  3050 
  3051   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3052   binary representation internally;
  3053 
  3054   - type nat has special constructor Suc, and generally prefers Suc 0
  3055   over 1::nat and Suc (Suc 0) over 2::nat;
  3056 
  3057 This change may cause significant problems of INCOMPATIBILITY; here
  3058 are some hints on converting existing sources:
  3059 
  3060   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3061   entities, so expressions involving "-" (unary or binary minus) need
  3062   to be spaced properly;
  3063 
  3064   - existing occurrences of "1" may need to be constraint "1::nat" or
  3065   even replaced by Suc 0; similar for old "2";
  3066 
  3067   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3068 
  3069   - remove all special provisions on numerals in proofs;
  3070 
  3071 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3072 representation (depends on bin_arith_simps in the default context);
  3073 
  3074 * HOL: symbolic syntax for x^2 (numeral 2);
  3075 
  3076 * HOL: the class of all HOL types is now called "type" rather than
  3077 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3078 in axclass/classes, instance/arities, and (usually rare) occurrences
  3079 in typings (of consts etc.); internally the class is called
  3080 "HOL.type", ML programs should refer to HOLogic.typeS;
  3081 
  3082 * HOL/record package improvements:
  3083   - new derived operations "fields" to build a partial record section,
  3084     "extend" to promote a fixed record to a record scheme, and
  3085     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3086     declared as simp by default;
  3087   - shared operations ("more", "fields", etc.) now need to be always
  3088     qualified) --- potential INCOMPATIBILITY;
  3089   - removed "make_scheme" operations (use "make" with "extend") --
  3090     INCOMPATIBILITY;
  3091   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3092   - provides cases/induct rules for use with corresponding Isar
  3093     methods (for concrete records, record schemes, concrete more
  3094     parts, and schematic more parts -- in that order);
  3095   - internal definitions directly based on a light-weight abstract
  3096     theory of product types over typedef rather than datatype;
  3097 
  3098 * HOL: generic code generator for generating executable ML code from
  3099 specifications; specific support for HOL constructs such as inductive
  3100 datatypes and sets, as well as recursive functions; can be invoked
  3101 via 'generate_code' theory section;
  3102 
  3103 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3104 
  3105 * HOL: consolidated and renamed several theories.  In particular:
  3106         Ord.thy has been absorbed into HOL.thy
  3107         String.thy has been absorbed into List.thy
  3108 
  3109 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3110 (beware of argument permutation!);
  3111 
  3112 * HOL: linorder_less_split superseded by linorder_cases;
  3113 
  3114 * HOL/List: "nodups" renamed to "distinct";
  3115 
  3116 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3117 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3118   - Ex_def has changed, now need to use some_eq_ex
  3119 
  3120 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3121 in this (rare) case use:
  3122 
  3123   delSWrapper "split_all_tac"
  3124   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3125 
  3126 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3127 MAY FAIL;
  3128 
  3129 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3130 Isabelle's type classes, ^ on functions and relations has too general
  3131 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3132 necessary to attach explicit type constraints;
  3133 
  3134 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3135 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3136 renamed accordingly (eg "compI" -> "rel_compI").
  3137 
  3138 * HOL: syntax translations now work properly with numerals and records
  3139 expressions;
  3140 
  3141 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3142 of "lam" -- INCOMPATIBILITY;
  3143 
  3144 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3145 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3146 renamed "Product_Type.unit";
  3147 
  3148 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3149 
  3150 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3151 the "cases" method);
  3152 
  3153 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3154 Florian Kammller);
  3155 
  3156 * HOL/IMP: updated and converted to new-style theory format; several
  3157 parts turned into readable document, with proper Isar proof texts and
  3158 some explanations (by Gerwin Klein);
  3159 
  3160 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3161 
  3162 * HOL-Hyperreal is now a logic image;
  3163 
  3164 
  3165 *** HOLCF ***
  3166 
  3167 * Isar: consts/constdefs supports mixfix syntax for continuous
  3168 operations;
  3169 
  3170 * Isar: domain package adapted to new-style theory format, e.g. see
  3171 HOLCF/ex/Dnat.thy;
  3172 
  3173 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3174 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3175 lift.induct_tac, always use UU instead of Undef;
  3176 
  3177 * HOLCF/IMP: updated and converted to new-style theory;
  3178 
  3179 
  3180 *** ZF ***
  3181 
  3182 * Isar: proper integration of logic-specific tools and packages,
  3183 including theory commands '(co)inductive', '(co)datatype',
  3184 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3185 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3186 
  3187 * theory Main no longer includes AC; for the Axiom of Choice, base
  3188 your theory on Main_ZFC;
  3189 
  3190 * the integer library now covers quotients and remainders, with many
  3191 laws relating division to addition, multiplication, etc.;
  3192 
  3193 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3194 typeless version of the formalism;
  3195 
  3196 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3197 format;
  3198 
  3199 * ZF/Induct: new directory for examples of inductive definitions,
  3200 including theory Multiset for multiset orderings; converted to
  3201 new-style theory format;
  3202 
  3203 * ZF: many new theorems about lists, ordinals, etc.;
  3204 
  3205 
  3206 *** General ***
  3207 
  3208 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3209 variable proof controls level of detail: 0 = no proofs (only oracle
  3210 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3211 also ref manual for further ML interfaces;
  3212 
  3213 * Pure/axclass: removed obsolete ML interface
  3214 goal_subclass/goal_arity;
  3215 
  3216 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3217 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3218 separate tokens, so expressions involving minus need to be spaced
  3219 properly;
  3220 
  3221 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3222 rather than "infixl" or "infixr";
  3223 
  3224 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3225 sort constraint specifications in type inference; e.g. "x::_::foo"
  3226 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3227 type variable);
  3228 
  3229 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3230 control output of nested => (types); the default behavior is
  3231 "type_brackets";
  3232 
  3233 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3234 tokens into AST constants;
  3235 
  3236 * Pure/syntax: prefer later declarations of translations and print
  3237 translation functions; potential INCOMPATIBILITY: need to reverse
  3238 multiple declarations for same syntax element constant;
  3239 
  3240 * Pure/show_hyps reset by default (in accordance to existing Isar
  3241 practice);
  3242 
  3243 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3244 addSafter;
  3245 
  3246 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3247 as well;
  3248 
  3249 * system: tested support for MacOS X; should be able to get Isabelle +
  3250 Proof General to work in a plain Terminal after installing Poly/ML
  3251 (e.g. from the Isabelle distribution area) and GNU bash alone
  3252 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3253 support requires further installations, e.g. from
  3254 http://fink.sourceforge.net/);
  3255 
  3256 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3257 
  3258 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3259 of 40 MB), cf. ML_OPTIONS;
  3260 
  3261 * system: Proof General keywords specification is now part of the
  3262 Isabelle distribution (see etc/isar-keywords.el);
  3263 
  3264 * system: support for persistent Proof General sessions (refrain from
  3265 outdating all loaded theories on startup); user may create writable
  3266 logic images like this: ``isabelle -q HOL Test'';
  3267 
  3268 * system: smart selection of Isabelle process versus Isabelle
  3269 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3270 run both "isabelle" and "Isabelle" even if file names are badly
  3271 damaged (executable inspects the case of the first letter of its own
  3272 name); added separate "isabelle-process" and "isabelle-interface";
  3273 
  3274 * system: refrain from any attempt at filtering input streams; no
  3275 longer support ``8bit'' encoding of old isabelle font, instead proper
  3276 iso-latin characters may now be used; the related isatools
  3277 "symbolinput" and "nonascii" have disappeared as well;
  3278 
  3279 * system: removed old "xterm" interface (the print modes "xterm" and
  3280 "xterm_color" are still available for direct use in a suitable
  3281 terminal);
  3282 
  3283 
  3284 
  3285 New in Isabelle99-2 (February 2001)
  3286 -----------------------------------
  3287 
  3288 *** Overview of INCOMPATIBILITIES ***
  3289 
  3290 * HOL: please note that theories in the Library and elsewhere often use the
  3291 new-style (Isar) format; to refer to their theorems in an ML script you must
  3292 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3293 
  3294 * HOL: inductive package no longer splits induction rule aggressively,
  3295 but only as far as specified by the introductions given; the old
  3296 format may be recovered via ML function complete_split_rule or attribute
  3297 'split_rule (complete)';
  3298 
  3299 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3300 gfp_Tarski to gfp_unfold;
  3301 
  3302 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3303 
  3304 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3305 relation); infix "^^" has been renamed "``"; infix "``" has been
  3306 renamed "`"; "univalent" has been renamed "single_valued";
  3307 
  3308 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3309 operation;
  3310 
  3311 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3312 
  3313 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3314 
  3315 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3316 consequence, it is no longer monotonic wrt. the local goal context
  3317 (which is now passed through the inductive cases);
  3318 
  3319 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3320 \<gg> to \<ggreater>;
  3321 
  3322 
  3323 *** Document preparation ***
  3324 
  3325 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3326 available: are "it" for near math-mode best-style output, "sl" for
  3327 slanted text style, and "tt" for plain type-writer; if no
  3328 \isabellestyle command is given, output is according to slanted
  3329 type-writer);
  3330 
  3331 * support sub/super scripts (for single symbols only), input syntax is
  3332 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3333 
  3334 * some more standard symbols; see Appendix A of the system manual for
  3335 the complete list of symbols defined in isabellesym.sty;
  3336 
  3337 * improved isabelle style files; more abstract symbol implementation
  3338 (should now use \isamath{...} and \isatext{...} in custom symbol
  3339 definitions);
  3340 
  3341 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3342 state; Note that presentation of goal states does not conform to
  3343 actual human-readable proof documents.  Please do not include goal
  3344 states into document output unless you really know what you are doing!
  3345 
  3346 * proper indentation of antiquoted output with proportional LaTeX
  3347 fonts;
  3348 
  3349 * no_document ML operator temporarily disables LaTeX document
  3350 generation;
  3351 
  3352 * isatool unsymbolize tunes sources for plain ASCII communication;
  3353 
  3354 
  3355 *** Isar ***
  3356 
  3357 * Pure: Isar now suffers initial goal statements to contain unbound
  3358 schematic variables (this does not conform to actual readable proof
  3359 documents, due to unpredictable outcome and non-compositional proof
  3360 checking); users who know what they are doing may use schematic goals
  3361 for Prolog-style synthesis of proven results;
  3362 
  3363 * Pure: assumption method (an implicit finishing) now handles actual
  3364 rules as well;
  3365 
  3366 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3367 initial goal, declare "that" only as Pure intro (only for single
  3368 steps); the "that" rule assumption may now be involved in implicit
  3369 finishing, thus ".." becomes a feasible for trivial obtains;
  3370 
  3371 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3372 instance proofs may be performed by "..";
  3373 
  3374 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3375 statements as well;
  3376 
  3377 * Pure: more robust selection of calculational rules;
  3378 
  3379 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3380 rule (as well as the assumption rule);
  3381 
  3382 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3383 lemmas, using the graph browser tool;
  3384 
  3385 * Pure: predict failure of "show" in interactive mode;
  3386 
  3387 * Pure: 'thms_containing' now takes actual terms as arguments;
  3388 
  3389 * HOL: improved method 'induct' --- now handles non-atomic goals
  3390 (potential INCOMPATIBILITY); tuned error handling;
  3391 
  3392 * HOL: cases and induct rules now provide explicit hints about the
  3393 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3394 any remaining facts are inserted into the goal verbatim;
  3395 
  3396 * HOL: local contexts (aka cases) may now contain term bindings as
  3397 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3398 the result to be shown in each case;
  3399 
  3400 * HOL: added 'recdef_tc' command;
  3401 
  3402 * isatool convert assists in eliminating legacy ML scripts;
  3403 
  3404 
  3405 *** HOL ***
  3406 
  3407 * HOL/Library: a collection of generic theories to be used together
  3408 with main HOL; the theory loader path already includes this directory
  3409 by default; the following existing theories have been moved here:
  3410 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3411 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3412 
  3413 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3414 modelling and verification task performed in Isabelle/HOL +
  3415 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3416 
  3417 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3418 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3419 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3420 'domain', this makes the theory consistent with mathematical
  3421 literature;
  3422 
  3423 * HOL basics: added overloaded operations "inverse" and "divide"
  3424 (infix "/"), syntax for generic "abs" operation, generic summation
  3425 operator \<Sum>;
  3426 
  3427 * HOL/typedef: simplified package, provide more useful rules (see also
  3428 HOL/subset.thy);
  3429 
  3430 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3431 now expressed as a proper nested rule (old-style tactic scripts may
  3432 require atomize_strip_tac to cope with non-atomic premises);
  3433 
  3434 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3435 to "split_conv" (old name still available for compatibility);
  3436 
  3437 * HOL: improved concrete syntax for strings (e.g. allows translation
  3438 rules with string literals);
  3439 
  3440 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3441  and Fleuriot's mechanization of analysis, including the transcendental
  3442  functions for the reals;
  3443 
  3444 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3445 
  3446 
  3447 *** CTT ***
  3448 
  3449 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3450 "lam" is displayed as TWO lambda-symbols
  3451 
  3452 * CTT: theory Main now available, containing everything (that is, Bool
  3453 and Arith);
  3454 
  3455 
  3456 *** General ***
  3457 
  3458 * Pure: the Simplifier has been implemented properly as a derived rule
  3459 outside of the actual kernel (at last!); the overall performance
  3460 penalty in practical applications is about 50%, while reliability of
  3461 the Isabelle inference kernel has been greatly improved;
  3462 
  3463 * print modes "brackets" and "no_brackets" control output of nested =>
  3464 (types) and ==> (props); the default behaviour is "brackets";
  3465 
  3466 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3467 as assumptions as well;
  3468 
  3469 * system: support Poly/ML 4.0;
  3470 
  3471 * system: isatool install handles KDE version 1 or 2;
  3472 
  3473 
  3474 
  3475 New in Isabelle99-1 (October 2000)
  3476 ----------------------------------
  3477 
  3478 *** Overview of INCOMPATIBILITIES ***
  3479 
  3480 * HOL: simplification of natural numbers is much changed; to partly
  3481 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3482 issue the following ML commands:
  3483 
  3484   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3485   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3486 
  3487 * HOL: simplification no longer dives into case-expressions; this is
  3488 controlled by "t.weak_case_cong" for each datatype t;
  3489 
  3490 * HOL: nat_less_induct renamed to less_induct;
  3491 
  3492 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3493 fixsome to patch .thy and .ML sources automatically;
  3494 
  3495   select_equality  -> some_equality
  3496   select_eq_Ex     -> some_eq_ex
  3497   selectI2EX       -> someI2_ex
  3498   selectI2         -> someI2
  3499   selectI          -> someI
  3500   select1_equality -> some1_equality
  3501   Eps_sym_eq       -> some_sym_eq_trivial
  3502   Eps_eq           -> some_eq_trivial
  3503 
  3504 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3505 
  3506 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3507 instead);
  3508 
  3509 * HOL: the recursion equations generated by 'recdef' are now called
  3510 f.simps instead of f.rules;
  3511 
  3512 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3513 
  3514 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3515 sometimes be needed;
  3516 
  3517 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3518 
  3519 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3520 
  3521 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3522 product is now "<*>" instead of "Times"; the lexicographic product is
  3523 now "<*lex*>" instead of "**";
  3524 
  3525 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3526 of main HOL, but was unused); better use HOL's datatype package;
  3527 
  3528 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3529 the old syntax may be recovered as follows:
  3530 
  3531   syntax (symbols)
  3532     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3533       (infixl "\\<oplus>" 100)
  3534 
  3535 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3536 
  3537 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3538 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3539 internally;
  3540 
  3541 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3542 changed from A/r to A//r;
  3543 
  3544 * ZF: new treatment of arithmetic (nat & int) may break some old
  3545 proofs;
  3546 
  3547 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3548 rulify -> rule_format, elimify -> elim_format, ...);
  3549 
  3550 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3551 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3552 should have to change intro!! to intro? only); replaced "delrule" by
  3553 "rule del";
  3554 
  3555 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3556 
  3557 * Provers: strengthened force_tac by using new first_best_tac;
  3558 
  3559 * LaTeX document preparation: several changes of isabelle.sty (see
  3560 lib/texinputs);
  3561 
  3562 
  3563 *** Document preparation ***
  3564 
  3565 * formal comments (text blocks etc.) in new-style theories may now
  3566 contain antiquotations of thm/prop/term/typ/text to be presented
  3567 according to latex print mode; concrete syntax is like this:
  3568 @{term[show_types] "f(x) = a + x"};
  3569 
  3570 * isatool mkdir provides easy setup of Isabelle session directories,
  3571 including proper document sources;
  3572 
  3573 * generated LaTeX sources are now deleted after successful run
  3574 (isatool document -c); may retain a copy somewhere else via -D option
  3575 of isatool usedir;
  3576 
  3577 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3578 style files, achieving self-contained LaTeX sources and simplifying
  3579 LaTeX debugging;
  3580 
  3581 * old-style theories now produce (crude) LaTeX output as well;
  3582 
  3583 * browser info session directories are now self-contained (may be put
  3584 on WWW server seperately); improved graphs of nested sessions; removed
  3585 graph for 'all sessions';
  3586 
  3587 * several improvements in isabelle style files; \isabellestyle{it}
  3588 produces fake math mode output; \isamarkupheader is now \section by
  3589 default; see lib/texinputs/isabelle.sty etc.;
  3590 
  3591 
  3592 *** Isar ***
  3593 
  3594 * Isar/Pure: local results and corresponding term bindings are now
  3595 subject to Hindley-Milner polymorphism (similar to ML); this
  3596 accommodates incremental type-inference very nicely;
  3597 
  3598 * Isar/Pure: new derived language element 'obtain' supports
  3599 generalized existence reasoning;
  3600 
  3601 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3602 support accumulation of results, without applying any rules yet;
  3603 useful to collect intermediate results without explicit name
  3604 references, and for use with transitivity rules with more than 2
  3605 premises;
  3606 
  3607 * Isar/Pure: scalable support for case-analysis type proofs: new
  3608 'case' language element refers to local contexts symbolically, as
  3609 produced by certain proof methods; internally, case names are attached
  3610 to theorems as "tags";
  3611 
  3612 * Isar/Pure: theory command 'hide' removes declarations from
  3613 class/type/const name spaces;
  3614 
  3615 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3616 indicate potential overloading;
  3617 
  3618 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3619 
  3620 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3621 "{a,b,c}" instead of {a,b,c};
  3622 
  3623 * Isar/Pure now provides its own version of intro/elim/dest
  3624 attributes; useful for building new logics, but beware of confusion
  3625 with the version in Provers/classical;
  3626 
  3627 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3628 case name 'antecedent';
  3629 
  3630 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3631 to the current context is now done automatically);
  3632 
  3633 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3634 for definining proof methods in ML;
  3635 
  3636 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3637 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3638 most cases, one should have to change intro!! to intro? only);
  3639 replaced "delrule" by "rule del";
  3640 
  3641 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3642 'symmetric' attribute (the latter supercedes [RS sym]);
  3643 
  3644 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3645 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3646 well (including splits);
  3647 
  3648 * Isar/Provers: Simplifier and Classical methods now support all kind
  3649 of modifiers used in the past, including 'cong', 'iff', etc.
  3650 
  3651 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3652 of Simplifier and Classical reasoner);
  3653 
  3654 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3655 now support named cases; major packages (inductive, datatype, primrec,
  3656 recdef) support case names and properly name parameters;
  3657 
  3658 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3659 monotonicity conditions are extracted to be proven at end of
  3660 calculations;
  3661 
  3662 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3663 method anyway;
  3664 
  3665 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3666 split_if split_if_asm; datatype package provides theorems foo.splits =
  3667 foo.split foo.split_asm for each datatype;
  3668 
  3669 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3670 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3671 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3672 use "(cases (simplified))" method in proper proof texts);
  3673 
  3674 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3675 
  3676 * Isar: names of theorems etc. may be natural numbers as well;
  3677 
  3678 * Isar: 'pr' command: optional arguments for goals_limit and
  3679 ProofContext.prems_limit; no longer prints theory contexts, but only
  3680 proof states;
  3681 
  3682 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3683 additional print modes to be specified; e.g. "pr(latex)" will print
  3684 proof state according to the Isabelle LaTeX style;
  3685 
  3686 * Isar: improved support for emulating tactic scripts, including proof
  3687 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3688 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3689 (for HOL datatypes);
  3690 
  3691 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3692 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3693 'proof method scripts' have to be in depth-first order;
  3694 
  3695 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3696 
  3697 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3698 should instead use individual commands for printing items
  3699 (print_commands, print_methods etc.);
  3700 
  3701 * Isar: added 'nothing' --- the empty list of theorems;
  3702 
  3703 
  3704 *** HOL ***
  3705 
  3706 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3707 corresponding virtual machine and a specification of its bytecode
  3708 verifier and a lightweight bytecode verifier, including proofs of
  3709 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3710 Cornelia Pusch (see also the homepage of project Bali at
  3711 http://isabelle.in.tum.de/Bali/);
  3712 
  3713 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3714 Clemens Ballarin;
  3715 
  3716 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3717 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3718 Rasmussen;
  3719 
  3720 * HOL/Lattice: fundamental concepts of lattice theory and order
  3721 structures, including duals, properties of bounds versus algebraic
  3722 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3723 Theorem for complete lattices etc.; may also serve as a demonstration
  3724 for abstract algebraic reasoning using axiomatic type classes, and
  3725 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3726 
  3727 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3728 von Oheimb;
  3729 
  3730 * HOL/IMPP: extension of IMP with local variables and mutually
  3731 recursive procedures, by David von Oheimb;
  3732 
  3733 * HOL/Lambda: converted into new-style theory and document;
  3734 
  3735 * HOL/ex/Multiquote: example of multiple nested quotations and
  3736 anti-quotations -- basically a generalized version of de-Bruijn
  3737 representation; very useful in avoiding lifting of operations;
  3738 
  3739 * HOL/record: added general record equality rule to simpset; fixed
  3740 select-update simplification procedure to handle extended records as
  3741 well; admit "r" as field name;
  3742 
  3743 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3744 other numeric types and also as the identity of groups, rings, etc.;
  3745 
  3746 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3747 Types nat and int belong to this axclass;
  3748 
  3749 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3750    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3751    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3752   two terms #m*u and #n*u are replaced by #(m+n)*u
  3753     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3754   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3755     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3756 
  3757 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3758 powerful prover for predicate logic but knows nothing of clasets; see
  3759 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3760 
  3761 * HOL: new version of "case_tac" subsumes both boolean case split and
  3762 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3763 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3764 
  3765 * HOL: simplification no longer dives into case-expressions: only the
  3766 selector expression is simplified, but not the remaining arms; to
  3767 enable full simplification of case-expressions for datatype t, you may
  3768 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3769 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3770 
  3771 * HOL/recdef: the recursion equations generated by 'recdef' for
  3772 function 'f' are now called f.simps instead of f.rules; if all
  3773 termination conditions are proved automatically, these simplification
  3774 rules are added to the simpset, as in primrec; rules may be named
  3775 individually as well, resulting in a separate list of theorems for
  3776 each equation;
  3777 
  3778 * HOL/While is a new theory that provides a while-combinator. It
  3779 permits the definition of tail-recursive functions without the
  3780 provision of a termination measure. The latter is necessary once the
  3781 invariant proof rule for while is applied.
  3782 
  3783 * HOL: new (overloaded) notation for the set of elements below/above
  3784 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3785 
  3786 * HOL: theorems impI, allI, ballI bound as "strip";
  3787 
  3788 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3789 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3790 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3791 
  3792 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3793 
  3794 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3795 main HOL, but was unused);
  3796 
  3797 * HOL: fewer consts declared as global (e.g. have to refer to
  3798 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3799 
  3800 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3801 in case of overlap with user translations (e.g. judgements over
  3802 tuples); (note that the underlying logical represenation is still
  3803 bogus);
  3804 
  3805 
  3806 *** ZF ***
  3807 
  3808 * ZF: simplification automatically cancels common terms in arithmetic
  3809 expressions over nat and int;
  3810 
  3811 * ZF: new treatment of nat to minimize type-checking: all operators
  3812 coerce their operands to a natural number using the function natify,
  3813 making the algebraic laws unconditional;
  3814 
  3815 * ZF: as above, for int: operators coerce their operands to an integer
  3816 using the function intify;
  3817 
  3818 * ZF: the integer library now contains many of the usual laws for the
  3819 orderings, including $<=, and monotonicity laws for $+ and $*;
  3820 
  3821 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3822 simplification;
  3823 
  3824 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3825 to the simplifier and classical reasoner simultaneously;
  3826 
  3827 
  3828 *** General ***
  3829 
  3830 * Provers: blast_tac now handles actual object-logic rules as
  3831 assumptions; note that auto_tac uses blast_tac internally as well;
  3832 
  3833 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3834 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3835 
  3836 * Provers: delrules now handles destruct rules as well (no longer need
  3837 explicit make_elim);
  3838 
  3839 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3840   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3841 use instead the strong form,
  3842   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3843 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3844 from destruct-rules;
  3845 
  3846 * Provers: Simplifier.easy_setup provides a fast path to basic
  3847 Simplifier setup for new object-logics;
  3848 
  3849 * Pure: AST translation rules no longer require constant head on LHS;
  3850 
  3851 * Pure: improved name spaces: ambiguous output is qualified; support
  3852 for hiding of names;
  3853 
  3854 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3855 XSYMBOL_HOME; no longer need to do manual configuration in most
  3856 situations;
  3857 
  3858 * system: compression of ML heaps images may now be controlled via -c
  3859 option of isabelle and isatool usedir (currently only observed by
  3860 Poly/ML);
  3861 
  3862 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3863 useful for remote X11);
  3864 
  3865 * system: provide TAGS file for Isabelle sources;
  3866 
  3867 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3868 order;
  3869 
  3870 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3871 timing flag supersedes proof_timing and Toplevel.trace;
  3872 
  3873 * ML: new combinators |>> and |>>> for incremental transformations
  3874 with secondary results (e.g. certain theory extensions):
  3875 
  3876 * ML: PureThy.add_defs gets additional argument to indicate potential
  3877 overloading (usually false);
  3878 
  3879 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3880 results;
  3881 
  3882 
  3883 
  3884 New in Isabelle99 (October 1999)
  3885 --------------------------------
  3886 
  3887 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3888 
  3889 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3890 are no longer simplified.  (This allows the simplifier to unfold recursive
  3891 functional programs.)  To restore the old behaviour, declare
  3892 
  3893     Delcongs [if_weak_cong];
  3894 
  3895 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3896 complement;
  3897 
  3898 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3899 
  3900 * HOL/datatype: mutual_induct_tac no longer exists --
  3901   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3902 
  3903 * HOL/typedef: fixed type inference for representing set; type
  3904 arguments now have to occur explicitly on the rhs as type constraints;
  3905 
  3906 * ZF: The con_defs part of an inductive definition may no longer refer
  3907 to constants declared in the same theory;
  3908 
  3909 * HOL, ZF: the function mk_cases, generated by the inductive
  3910 definition package, has lost an argument.  To simplify its result, it
  3911 uses the default simpset instead of a supplied list of theorems.
  3912 
  3913 * HOL/List: the constructors of type list are now Nil and Cons;
  3914 
  3915 * Simplifier: the type of the infix ML functions
  3916         setSSolver addSSolver setSolver addSolver
  3917 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3918 for packaging solvers. A solver is created via
  3919         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3920 where the string argument is only a comment.
  3921 
  3922 
  3923 *** Proof tools ***
  3924 
  3925 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3926 decision procedure for linear arithmetic. Currently it is used for
  3927 types `nat', `int', and `real' in HOL (see below); it can, should and
  3928 will be instantiated for other types and logics as well.
  3929 
  3930 * The simplifier now accepts rewrite rules with flexible heads, eg
  3931      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3932   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3933   matching.
  3934 
  3935 
  3936 *** General ***
  3937 
  3938 * New Isabelle/Isar subsystem provides an alternative to traditional
  3939 tactical theorem proving; together with the ProofGeneral/isar user
  3940 interface it offers an interactive environment for developing human
  3941 readable proof documents (Isar == Intelligible semi-automated
  3942 reasoning); for further information see isatool doc isar-ref,
  3943 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3944 
  3945 * improved and simplified presentation of theories: better HTML markup
  3946 (including colors), graph views in several sizes; isatool usedir now
  3947 provides a proper interface for user theories (via -P option); actual
  3948 document preparation based on (PDF)LaTeX is available as well (for
  3949 new-style theories only); see isatool doc system for more information;
  3950 
  3951 * native support for Proof General, both for classic Isabelle and
  3952 Isabelle/Isar;
  3953 
  3954 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3955 using the graph browser tool;
  3956 
  3957 * Isabelle manuals now also available as PDF;
  3958 
  3959 * theory loader rewritten from scratch (may not be fully
  3960 bug-compatible); old loadpath variable has been replaced by show_path,
  3961 add_path, del_path, reset_path functions; new operations such as
  3962 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3963 isatool doc ref);
  3964 
  3965 * improved isatool install: option -k creates KDE application icon,
  3966 option -p DIR installs standalone binaries;
  3967 
  3968 * added ML_PLATFORM setting (useful for cross-platform installations);
  3969 more robust handling of platform specific ML images for SML/NJ;
  3970 
  3971 * the settings environment is now statically scoped, i.e. it is never
  3972 created again in sub-processes invoked from isabelle, isatool, or
  3973 Isabelle;
  3974 
  3975 * path element specification '~~' refers to '$ISABELLE_HOME';
  3976 
  3977 * in locales, the "assumes" and "defines" parts may be omitted if
  3978 empty;
  3979 
  3980 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3981 long arrows);
  3982 
  3983 * new print_mode "HTML";
  3984 
  3985 * new flag show_tags controls display of tags of theorems (which are
  3986 basically just comments that may be attached by some tools);
  3987 
  3988 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3989 mode and goal output format:
  3990 
  3991 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3992 244c244
  3993 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3994 ---
  3995 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3996 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3997 181c181
  3998 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3999 ---
  4000 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4001 
  4002 * function bind_thms stores lists of theorems (cf. bind_thm);
  4003 
  4004 * new shorthand tactics ftac, eatac, datac, fatac;
  4005 
  4006 * qed (and friends) now accept "" as result name; in that case the
  4007 theorem is not stored, but proper checks and presentation of the
  4008 result still apply;
  4009 
  4010 * theorem database now also indexes constants "Trueprop", "all",
  4011 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4012 
  4013 
  4014 *** HOL ***
  4015 
  4016 ** HOL arithmetic **
  4017 
  4018 * There are now decision procedures for linear arithmetic over nat and
  4019 int:
  4020 
  4021 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4022 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4023 are treated as atomic; subformulae not involving type `nat' or `int'
  4024 are ignored; quantified subformulae are ignored unless they are
  4025 positive universal or negative existential. The tactic has to be
  4026 invoked by hand and can be a little bit slow. In particular, the
  4027 running time is exponential in the number of occurrences of `min' and
  4028 `max', and `-' on `nat'.
  4029 
  4030 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4031 (negated) (in)equalities among the premises and the conclusion into
  4032 account (i.e. no compound formulae) and does not know about `min' and
  4033 `max', and `-' on `nat'. It is fast and is used automatically by the
  4034 simplifier.
  4035 
  4036 NB: At the moment, these decision procedures do not cope with mixed
  4037 nat/int formulae where the two parts interact, such as `m < n ==>
  4038 int(m) < int(n)'.
  4039 
  4040 * HOL/Numeral provides a generic theory of numerals (encoded
  4041 efficiently as bit strings); setup for types nat/int/real is in place;
  4042 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4043 int, existing theories and proof scripts may require a few additional
  4044 type constraints;
  4045 
  4046 * integer division and remainder can now be performed on constant
  4047 arguments;
  4048 
  4049 * many properties of integer multiplication, division and remainder
  4050 are now available;
  4051 
  4052 * An interface to the Stanford Validity Checker (SVC) is available through the
  4053 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4054 are proved automatically.  SVC must be installed separately, and its results
  4055 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4056 invocation of the underlying oracle).  For SVC see
  4057   http://verify.stanford.edu/SVC
  4058 
  4059 * IsaMakefile: the HOL-Real target now builds an actual image;
  4060 
  4061 
  4062 ** HOL misc **
  4063 
  4064 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4065 (in Isabelle/Isar) -- by Gertrud Bauer;
  4066 
  4067 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4068 analysis for assembly languages with subtypes;
  4069 
  4070 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4071 -- avoids syntactic ambiguities and treats state, transition, and
  4072 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4073 changed syntax and (many) tactics;
  4074 
  4075 * HOL/inductive: Now also handles more general introduction rules such
  4076   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4077   theorems are now maintained within the theory (maintained via the
  4078   "mono" attribute);
  4079 
  4080 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4081   (using function types) such as
  4082 
  4083   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4084 
  4085 * HOL/record: record_simproc (part of the default simpset) takes care
  4086 of selectors applied to updated records; record_split_tac is no longer
  4087 part of the default claset; update_defs may now be removed from the
  4088 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4089 
  4090   claset_ref () := claset() addSWrapper record_split_wrapper;
  4091   Delsimprocs [record_simproc]
  4092 
  4093 * HOL/typedef: fixed type inference for representing set; type
  4094 arguments now have to occur explicitly on the rhs as type constraints;
  4095 
  4096 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4097 names rather than an ML expression;
  4098 
  4099 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4100 supplied later.  Program schemes can be defined, such as
  4101     "While B C s = (if B s then While B C (C s) else s)"
  4102 where the well-founded relation can be chosen after B and C have been given.
  4103 
  4104 * HOL/List: the constructors of type list are now Nil and Cons;
  4105 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4106 course, ML tools referring to List.list.op # etc. have to be adapted;
  4107 
  4108 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4109 disabled by default; run isabelle with option -m HOL to get back to
  4110 the original Gordon/HOL-style output;
  4111 
  4112 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4113 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4114 
  4115 * HOL basic syntax simplified (more orthogonal): all variants of
  4116 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4117 Eps operator is provided as well: "SOME x. P[x]";
  4118 
  4119 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4120 
  4121 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4122 thus available for user theories;
  4123 
  4124 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4125 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4126 time;
  4127 
  4128 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4129 several times and then mp;
  4130 
  4131 
  4132 *** LK ***
  4133 
  4134 * the notation <<...>> is now available as a notation for sequences of
  4135 formulas;
  4136 
  4137 * the simplifier is now installed
  4138 
  4139 * the axiom system has been generalized (thanks to Soren Heilmann)
  4140 
  4141 * the classical reasoner now has a default rule database
  4142 
  4143 
  4144 *** ZF ***
  4145 
  4146 * new primrec section allows primitive recursive functions to be given
  4147 directly (as in HOL) over datatypes and the natural numbers;
  4148 
  4149 * new tactics induct_tac and exhaust_tac for induction (or case
  4150 analysis) over datatypes and the natural numbers;
  4151 
  4152 * the datatype declaration of type T now defines the recursor T_rec;
  4153 
  4154 * simplification automatically does freeness reasoning for datatype
  4155 constructors;
  4156 
  4157 * automatic type-inference, with AddTCs command to insert new
  4158 type-checking rules;
  4159 
  4160 * datatype introduction rules are now added as Safe Introduction rules
  4161 to the claset;
  4162 
  4163 * the syntax "if P then x else y" is now available in addition to
  4164 if(P,x,y);
  4165 
  4166 
  4167 *** Internal programming interfaces ***
  4168 
  4169 * tuned simplifier trace output; new flag debug_simp;
  4170 
  4171 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4172 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4173 
  4174 * AxClass.axclass_tac lost the theory argument;
  4175 
  4176 * tuned current_goals_markers semantics: begin / end goal avoids
  4177 printing empty lines;
  4178 
  4179 * removed prs and prs_fn hook, which was broken because it did not
  4180 include \n in its semantics, forcing writeln to add one
  4181 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4182 string -> unit if you really want to output text without newline;
  4183 
  4184 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4185 plain output, interface builders may have to enable 'isabelle_font'
  4186 mode to get Isabelle font glyphs as before;
  4187 
  4188 * refined token_translation interface; INCOMPATIBILITY: output length
  4189 now of type real instead of int;
  4190 
  4191 * theory loader actions may be traced via new ThyInfo.add_hook
  4192 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4193 your own database of information attached to *whole* theories -- as
  4194 opposed to intra-theory data slots offered via TheoryDataFun;
  4195 
  4196 * proper handling of dangling sort hypotheses (at last!);
  4197 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4198 extra sort hypotheses that can be witnessed from the type signature;
  4199 the force_strip_shyps flag is gone, any remaining shyps are simply
  4200 left in the theorem (with a warning issued by strip_shyps_warning);
  4201 
  4202 
  4203 
  4204 New in Isabelle98-1 (October 1998)
  4205 ----------------------------------
  4206 
  4207 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4208 
  4209 * several changes of automated proof tools;
  4210 
  4211 * HOL: major changes to the inductive and datatype packages, including
  4212 some minor incompatibilities of theory syntax;
  4213 
  4214 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4215 called `inj_on';
  4216 
  4217 * HOL: removed duplicate thms in Arith:
  4218   less_imp_add_less  should be replaced by  trans_less_add1
  4219   le_imp_add_le      should be replaced by  trans_le_add1
  4220 
  4221 * HOL: unary minus is now overloaded (new type constraints may be
  4222 required);
  4223 
  4224 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4225 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4226 now taken as an integer constant.
  4227 
  4228 * Pure: ML function 'theory_of' renamed to 'theory';
  4229 
  4230 
  4231 *** Proof tools ***
  4232 
  4233 * Simplifier:
  4234   1. Asm_full_simp_tac is now more aggressive.
  4235      1. It will sometimes reorient premises if that increases their power to
  4236         simplify.
  4237      2. It does no longer proceed strictly from left to right but may also
  4238         rotate premises to achieve further simplification.
  4239      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4240      old Asm_full_simp_tac in that it does not rotate premises.
  4241   2. The simplifier now knows a little bit about nat-arithmetic.
  4242 
  4243 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4244 allows for selected deletion of wrappers, by introduction of names for
  4245 wrapper functionals.  This implies that addbefore, addSbefore,
  4246 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4247 and that adding two tactics with the same name overwrites the first
  4248 one (emitting a warning).
  4249   type wrapper = (int -> tactic) -> (int -> tactic)
  4250   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4251   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4252   delWrapper, delSWrapper: claset *  string            -> claset
  4253   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4254 
  4255 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4256 semantics; addbefore now affects only the unsafe part of step_tac
  4257 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4258 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4259 by Force_tac;
  4260 
  4261 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4262 compWrapper; added safe wrapper (and access functions for it);
  4263 
  4264 * HOL/split_all_tac is now much faster and fails if there is nothing
  4265 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4266 and the names of the automatically generated variables have changed.
  4267 split_all_tac has moved within claset() from unsafe wrappers to safe
  4268 wrappers, which means that !!-bound variables are split much more
  4269 aggressively, and safe_tac and clarify_tac now split such variables.
  4270 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4271 Note: the same holds for record_split_tac, which does the job of
  4272 split_all_tac for record fields.
  4273 
  4274 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4275 permanently to the default simpset using Addsplits just like
  4276 Addsimps. They can be removed via Delsplits just like
  4277 Delsimps. Lower-case versions are also available.
  4278 
  4279 * HOL/Simplifier: The rule split_if is now part of the default
  4280 simpset. This means that the simplifier will eliminate all occurrences
  4281 of if-then-else in the conclusion of a goal. To prevent this, you can
  4282 either remove split_if completely from the default simpset by
  4283 `Delsplits [split_if]' or remove it in a specific call of the
  4284 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4285 other case splitting rules to/from the default simpset: every datatype
  4286 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4287 t is the name of the datatype).
  4288 
  4289 * Classical reasoner / Simplifier combination: new force_tac (and
  4290 derivatives Force_tac, force) combines rewriting and classical
  4291 reasoning (and whatever other tools) similarly to auto_tac, but is
  4292 aimed to solve the given subgoal completely.
  4293 
  4294 
  4295 *** General ***
  4296 
  4297 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4298 and `goalw': the theory is no longer needed as an explicit argument -
  4299 the current theory context is used; assumptions are no longer returned
  4300 at the ML-level unless one of them starts with ==> or !!; it is
  4301 recommended to convert to these new commands using isatool fixgoal
  4302 (backup your sources first!);
  4303 
  4304 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4305 the current theory context, and 'theory' to lookup stored theories;
  4306 
  4307 * new theory section 'locale' for declaring constants, assumptions and
  4308 definitions that have local scope;
  4309 
  4310 * new theory section 'nonterminals' for purely syntactic types;
  4311 
  4312 * new theory section 'setup' for generic ML setup functions
  4313 (e.g. package initialization);
  4314 
  4315 * the distribution now includes Isabelle icons: see
  4316 lib/logo/isabelle-{small,tiny}.xpm;
  4317 
  4318 * isatool install - install binaries with absolute references to
  4319 ISABELLE_HOME/bin;
  4320 
  4321 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4322 
  4323 * print mode 'emacs' reserved for Isamode;
  4324 
  4325 * support multiple print (ast) translations per constant name;
  4326 
  4327 * theorems involving oracles are now printed with a suffixed [!];
  4328 
  4329 
  4330 *** HOL ***
  4331 
  4332 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4333 
  4334 * HOL/inductive package reorganized and improved: now supports mutual
  4335 definitions such as
  4336 
  4337   inductive EVEN ODD
  4338     intrs
  4339       null "0 : EVEN"
  4340       oddI "n : EVEN ==> Suc n : ODD"
  4341       evenI "n : ODD ==> Suc n : EVEN"
  4342 
  4343 new theorem list "elims" contains an elimination rule for each of the
  4344 recursive sets; inductive definitions now handle disjunctive premises
  4345 correctly (also ZF);
  4346 
  4347 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4348 "mutual_induct" no longer exists - the induction rule is always
  4349 contained in "induct";
  4350 
  4351 
  4352 * HOL/datatype package re-implemented and greatly improved: now
  4353 supports mutually recursive datatypes such as
  4354 
  4355   datatype
  4356     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4357             | SUM ('a aexp) ('a aexp)
  4358             | DIFF ('a aexp) ('a aexp)
  4359             | NUM 'a
  4360   and
  4361     'a bexp = LESS ('a aexp) ('a aexp)
  4362             | AND ('a bexp) ('a bexp)
  4363             | OR ('a bexp) ('a bexp)
  4364 
  4365 as well as indirectly recursive datatypes such as
  4366 
  4367   datatype
  4368     ('a, 'b) term = Var 'a
  4369                   | App 'b ((('a, 'b) term) list)
  4370 
  4371 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4372 induction on mutually / indirectly recursive datatypes.
  4373 
  4374 Primrec equations are now stored in theory and can be accessed via
  4375 <function_name>.simps.
  4376 
  4377 INCOMPATIBILITIES:
  4378 
  4379   - Theories using datatypes must now have theory Datatype as an
  4380     ancestor.
  4381   - The specific <typename>.induct_tac no longer exists - use the
  4382     generic induct_tac instead.
  4383   - natE has been renamed to nat.exhaust - use exhaust_tac
  4384     instead of res_inst_tac ... natE. Note that the variable
  4385     names in nat.exhaust differ from the names in natE, this
  4386     may cause some "fragile" proofs to fail.
  4387   - The theorems split_<typename>_case and split_<typename>_case_asm
  4388     have been renamed to <typename>.split and <typename>.split_asm.
  4389   - Since default sorts of type variables are now handled correctly,
  4390     some datatype definitions may have to be annotated with explicit
  4391     sort constraints.
  4392   - Primrec definitions no longer require function name and type
  4393     of recursive argument.
  4394 
  4395 Consider using isatool fixdatatype to adapt your theories and proof
  4396 scripts to the new package (backup your sources first!).
  4397 
  4398 
  4399 * HOL/record package: considerably improved implementation; now
  4400 includes concrete syntax for record types, terms, updates; theorems
  4401 for surjective pairing and splitting !!-bound record variables; proof
  4402 support is as follows:
  4403 
  4404   1) standard conversions (selectors or updates applied to record
  4405 constructor terms) are part of the standard simpset;
  4406 
  4407   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4408 made part of standard simpset and claset via addIffs;
  4409 
  4410   3) a tactic for record field splitting (record_split_tac) is part of
  4411 the standard claset (addSWrapper);
  4412 
  4413 To get a better idea about these rules you may retrieve them via
  4414 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4415 the name of your record type.
  4416 
  4417 The split tactic 3) conceptually simplifies by the following rule:
  4418 
  4419   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4420 
  4421 Thus any record variable that is bound by meta-all will automatically
  4422 blow up into some record constructor term, consequently the
  4423 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4424 solve record problems automatically.
  4425 
  4426 
  4427 * reorganized the main HOL image: HOL/Integ and String loaded by
  4428 default; theory Main includes everything;
  4429 
  4430 * automatic simplification of integer sums and comparisons, using cancellation;
  4431 
  4432 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4433 
  4434 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4435 
  4436 * many new identities for unions, intersections, set difference, etc.;
  4437 
  4438 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4439 called split_if, split_split, split_sum_case and split_nat_case (to go
  4440 with add/delsplits);
  4441 
  4442 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4443 (?x::unit) = (); this is made part of the default simpset, which COULD
  4444 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4445 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4446 unit_abs_eta_conv is added in order to counter the effect of
  4447 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4448 %u.f();
  4449 
  4450 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4451 makes more sense);
  4452 
  4453 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4454   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4455   disjointness reasoning but breaking a few old proofs.
  4456 
  4457 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4458 to 'converse' from 'inverse' (for compatibility with ZF and some
  4459 literature);
  4460 
  4461 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4462 the well-founded relation;
  4463 
  4464 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4465     Compl A.  The "Compl" syntax remains available as input syntax for this
  4466     release ONLY.
  4467 
  4468 * HOL/Update: new theory of function updates:
  4469     f(a:=b) == %x. if x=a then b else f x
  4470 may also be iterated as in f(a:=b,c:=d,...);
  4471 
  4472 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4473 
  4474 * HOL/List:
  4475   - new function list_update written xs[i:=v] that updates the i-th
  4476     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4477   - new function `upt' written [i..j(] which generates the list
  4478     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4479     bound write [i..j], which is a shorthand for [i..j+1(].
  4480   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4481 
  4482 * HOL/Arith:
  4483   - removed 'pred' (predecessor) function;
  4484   - generalized some theorems about n-1;
  4485   - many new laws about "div" and "mod";
  4486   - new laws about greatest common divisors (see theory ex/Primes);
  4487 
  4488 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4489 instead of "inverse";
  4490 
  4491 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4492   of the multiset ordering;
  4493 
  4494 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4495   (not included by default);
  4496 
  4497 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4498 
  4499 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4500   programs, i.e. different program variables may have different types.
  4501 
  4502 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4503   [previously, this check worked only if the rewrite rule was unconditional]
  4504   Now rew can involve either definitions or equalities (either == or =).
  4505 
  4506 
  4507 *** ZF ***
  4508 
  4509 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4510   only the theorems proved on ZF.ML;
  4511 
  4512 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4513   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4514   disjointness reasoning but breaking a few old proofs.
  4515 
  4516 * ZF/Update: new theory of function updates
  4517     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4518   may also be iterated as in f(a:=b,c:=d,...);
  4519 
  4520 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4521 
  4522 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4523   [previously, this check worked only if the rewrite rule was unconditional]
  4524   Now rew can involve either definitions or equalities (either == or =).
  4525 
  4526 * case_tac provided for compatibility with HOL
  4527     (like the old excluded_middle_tac, but with subgoals swapped)
  4528 
  4529 
  4530 *** Internal programming interfaces ***
  4531 
  4532 * Pure: several new basic modules made available for general use, see
  4533 also src/Pure/README;
  4534 
  4535 * improved the theory data mechanism to support encapsulation (data
  4536 kind name replaced by private Object.kind, acting as authorization
  4537 key); new type-safe user interface via functor TheoryDataFun; generic
  4538 print_data function becomes basically useless;
  4539 
  4540 * removed global_names compatibility flag -- all theory declarations
  4541 are qualified by default;
  4542 
  4543 * module Pure/Syntax now offers quote / antiquote translation
  4544 functions (useful for Hoare logic etc. with implicit dependencies);
  4545 see HOL/ex/Antiquote for an example use;
  4546 
  4547 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4548 cterm -> thm;
  4549 
  4550 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4551 subgoal;
  4552 
  4553 * Display.print_goals function moved to Locale.print_goals;
  4554 
  4555 * standard print function for goals supports current_goals_markers
  4556 variable for marking begin of proof, end of proof, start of goal; the
  4557 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4558 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4559 for example;
  4560 
  4561 
  4562 
  4563 New in Isabelle98 (January 1998)
  4564 --------------------------------
  4565 
  4566 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4567 
  4568 * changed lexical syntax of terms / types: dots made part of long
  4569 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4570 
  4571 * simpset (and claset) reference variable replaced by functions
  4572 simpset / simpset_ref;
  4573 
  4574 * no longer supports theory aliases (via merge) and non-trivial
  4575 implicit merge of thms' signatures;
  4576 
  4577 * most internal names of constants changed due to qualified names;
  4578 
  4579 * changed Pure/Sequence interface (see Pure/seq.ML);
  4580 
  4581 
  4582 *** General Changes ***
  4583 
  4584 * hierachically structured name spaces (for consts, types, axms, thms
  4585 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4586 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4587 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4588 long_names for fully qualified output names; NOTE: ML programs
  4589 (special tactics, packages etc.) referring to internal names may have
  4590 to be adapted to cope with fully qualified names; in case of severe
  4591 backward campatibility problems try setting 'global_names' at compile
  4592 time to have enrything declared within a flat name space; one may also
  4593 fine tune name declarations in theories via the 'global' and 'local'
  4594 section;
  4595 
  4596 * reimplemented the implicit simpset and claset using the new anytype
  4597 data filed in signatures; references simpset:simpset ref etc. are
  4598 replaced by functions simpset:unit->simpset and
  4599 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4600 to patch your ML files accordingly;
  4601 
  4602 * HTML output now includes theory graph data for display with Java
  4603 applet or isatool browser; data generated automatically via isatool
  4604 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4605 
  4606 * defs may now be conditional; improved rewrite_goals_tac to handle
  4607 conditional equations;
  4608 
  4609 * defs now admits additional type arguments, using TYPE('a) syntax;
  4610 
  4611 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4612 creates a new theory node; implicit merge of thms' signatures is
  4613 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4614 transfer:theory->thm->thm in (rare) cases;
  4615 
  4616 * improved handling of draft signatures / theories; draft thms (and
  4617 ctyps, cterms) are automatically promoted to real ones;
  4618 
  4619 * slightly changed interfaces for oracles: admit many per theory, named
  4620 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4621 
  4622 * print_goals: optional output of const types (set show_consts and
  4623 show_types);
  4624 
  4625 * improved output of warnings (###) and errors (***);
  4626 
  4627 * subgoal_tac displays a warning if the new subgoal has type variables;
  4628 
  4629 * removed old README and Makefiles;
  4630 
  4631 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4632 
  4633 * removed obsolete init_pps and init_database;
  4634 
  4635 * deleted the obsolete tactical STATE, which was declared by
  4636     fun STATE tacfun st = tacfun st st;
  4637 
  4638 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4639 (which abbreviates $HOME);
  4640 
  4641 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4642 use isatool fixseq to adapt your ML programs (this works for fully
  4643 qualified references to the Sequence structure only!);
  4644 
  4645 * use_thy no longer requires writable current directory; it always
  4646 reloads .ML *and* .thy file, if either one is out of date;
  4647 
  4648 
  4649 *** Classical Reasoner ***
  4650 
  4651 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4652 tactics that use classical reasoning to simplify a subgoal without
  4653 splitting it into several subgoals;
  4654 
  4655 * Safe_tac: like safe_tac but uses the default claset;
  4656 
  4657 
  4658 *** Simplifier ***
  4659 
  4660 * added simplification meta rules:
  4661     (asm_)(full_)simplify: simpset -> thm -> thm;
  4662 
  4663 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4664 logics (again);
  4665 
  4666 * added prems argument to simplification procedures;
  4667 
  4668 * HOL, FOL, ZF: added infix function `addsplits':
  4669   instead of `<simpset> setloop (split_tac <thms>)'
  4670   you can simply write `<simpset> addsplits <thms>'
  4671 
  4672 
  4673 *** Syntax ***
  4674 
  4675 * TYPE('a) syntax for type reflection terms;
  4676 
  4677 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4678 
  4679 * pretty printer: changed order of mixfix annotation preference (again!);
  4680 
  4681 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4682 
  4683 
  4684 *** HOL ***
  4685 
  4686 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4687   with `addloop' of the simplifier to faciliate case splitting in premises.
  4688 
  4689 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4690 
  4691 * HOL/Auth: new protocol proofs including some for the Internet
  4692   protocol TLS;
  4693 
  4694 * HOL/Map: new theory of `maps' a la VDM;
  4695 
  4696 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4697 cancelling out common nat summands from =, <, <= (in)equalities, or
  4698 differences; simplification procedures nat_cancel_factor for
  4699 cancelling common factor from =, <, <= (in)equalities over natural
  4700 sums; nat_cancel contains both kinds of procedures, it is installed by
  4701 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4702 
  4703 * HOL/simplifier: terms of the form
  4704   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4705   are rewritten to
  4706   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4707   and those of the form
  4708   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4709   are rewritten to
  4710   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4711 
  4712 * HOL/datatype
  4713   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4714 
  4715   P(t_case f1 ... fn x) =
  4716      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4717         ...
  4718        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4719      )
  4720 
  4721   and a theorem `split_t_case_asm' of the form
  4722 
  4723   P(t_case f1 ... fn x) =
  4724     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4725         ...
  4726        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4727      )
  4728   which can be added to a simpset via `addsplits'. The existing theorems
  4729   expand_list_case and expand_option_case have been renamed to
  4730   split_list_case and split_option_case.
  4731 
  4732 * HOL/Arithmetic:
  4733   - `pred n' is automatically converted to `n-1'.
  4734     Users are strongly encouraged not to use `pred' any longer,
  4735     because it will disappear altogether at some point.
  4736   - Users are strongly encouraged to write "0 < n" rather than
  4737     "n ~= 0". Theorems and proof tools have been modified towards this
  4738     `standard'.
  4739 
  4740 * HOL/Lists:
  4741   the function "set_of_list" has been renamed "set" (and its theorems too);
  4742   the function "nth" now takes its arguments in the reverse order and
  4743   has acquired the infix notation "!" as in "xs!n".
  4744 
  4745 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4746 
  4747 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4748   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4749 
  4750 * HOL/record: extensible records with schematic structural subtyping
  4751 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4752 still lacks various theorems and concrete record syntax;
  4753 
  4754 
  4755 *** HOLCF ***
  4756 
  4757 * removed "axioms" and "generated by" sections;
  4758 
  4759 * replaced "ops" section by extended "consts" section, which is capable of
  4760   handling the continuous function space "->" directly;
  4761 
  4762 * domain package:
  4763   . proves theorems immediately and stores them in the theory,
  4764   . creates hierachical name space,
  4765   . now uses normal mixfix annotations (instead of cinfix...),
  4766   . minor changes to some names and values (for consistency),
  4767   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4768   . separator between mutual domain defs: changed "," to "and",
  4769   . improved handling of sort constraints;  now they have to
  4770     appear on the left-hand side of the equations only;
  4771 
  4772 * fixed LAM <x,y,zs>.b syntax;
  4773 
  4774 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4775 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4776 
  4777 
  4778 *** FOL and ZF ***
  4779 
  4780 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4781   with `addloop' of the simplifier to faciliate case splitting in premises.
  4782 
  4783 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4784 in HOL, they strip ALL and --> from proved theorems;
  4785 
  4786 
  4787 
  4788 New in Isabelle94-8 (May 1997)
  4789 ------------------------------
  4790 
  4791 *** General Changes ***
  4792 
  4793 * new utilities to build / run / maintain Isabelle etc. (in parts
  4794 still somewhat experimental); old Makefiles etc. still functional;
  4795 
  4796 * new 'Isabelle System Manual';
  4797 
  4798 * INSTALL text, together with ./configure and ./build scripts;
  4799 
  4800 * reimplemented type inference for greater efficiency, better error
  4801 messages and clean internal interface;
  4802 
  4803 * prlim command for dealing with lots of subgoals (an easier way of
  4804 setting goals_limit);
  4805 
  4806 
  4807 *** Syntax ***
  4808 
  4809 * supports alternative (named) syntax tables (parser and pretty
  4810 printer); internal interface is provided by add_modesyntax(_i);
  4811 
  4812 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4813 be used in conjunction with the Isabelle symbol font; uses the
  4814 "symbols" syntax table;
  4815 
  4816 * added token_translation interface (may translate name tokens in
  4817 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4818 the current print_mode); IMPORTANT: user print translation functions
  4819 are responsible for marking newly introduced bounds
  4820 (Syntax.mark_boundT);
  4821 
  4822 * token translations for modes "xterm" and "xterm_color" that display
  4823 names in bold, underline etc. or colors (which requires a color
  4824 version of xterm);
  4825 
  4826 * infixes may now be declared with names independent of their syntax;
  4827 
  4828 * added typed_print_translation (like print_translation, but may
  4829 access type of constant);
  4830 
  4831 
  4832 *** Classical Reasoner ***
  4833 
  4834 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4835 some limitations.  Blast_tac...
  4836   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4837   + ignores elimination rules that don't have the correct format
  4838         (the conclusion MUST be a formula variable)
  4839   + ignores types, which can make HOL proofs fail
  4840   + rules must not require higher-order unification, e.g. apply_type in ZF
  4841     [message "Function Var's argument not a bound variable" relates to this]
  4842   + its proof strategy is more general but can actually be slower
  4843 
  4844 * substitution with equality assumptions no longer permutes other
  4845 assumptions;
  4846 
  4847 * minor changes in semantics of addafter (now called addaltern); renamed
  4848 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4849 (and access functions for it);
  4850 
  4851 * improved combination of classical reasoner and simplifier:
  4852   + functions for handling clasimpsets
  4853   + improvement of addss: now the simplifier is called _after_ the
  4854     safe steps.
  4855   + safe variant of addss called addSss: uses safe simplifications
  4856     _during_ the safe steps. It is more complete as it allows multiple
  4857     instantiations of unknowns (e.g. with slow_tac).
  4858 
  4859 *** Simplifier ***
  4860 
  4861 * added interface for simplification procedures (functions that
  4862 produce *proven* rewrite rules on the fly, depending on current
  4863 redex);
  4864 
  4865 * ordering on terms as parameter (used for ordered rewriting);
  4866 
  4867 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4868 
  4869 * the solver is now split into a safe and an unsafe part.
  4870 This should be invisible for the normal user, except that the
  4871 functions setsolver and addsolver have been renamed to setSolver and
  4872 addSolver; added safe_asm_full_simp_tac;
  4873 
  4874 
  4875 *** HOL ***
  4876 
  4877 * a generic induction tactic `induct_tac' which works for all datatypes and
  4878 also for type `nat';
  4879 
  4880 * a generic case distinction tactic `exhaust_tac' which works for all
  4881 datatypes and also for type `nat';
  4882 
  4883 * each datatype comes with a function `size';
  4884 
  4885 * patterns in case expressions allow tuple patterns as arguments to
  4886 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4887 
  4888 * primrec now also works with type nat;
  4889 
  4890 * recdef: a new declaration form, allows general recursive functions to be
  4891 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4892 
  4893 * the constant for negation has been renamed from "not" to "Not" to
  4894 harmonize with FOL, ZF, LK, etc.;
  4895 
  4896 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4897 infinite lists;
  4898 
  4899 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4900 
  4901 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4902 problems in commutative rings, using axiomatic type classes for + and *;
  4903 
  4904 * more examples in HOL/MiniML and HOL/Auth;
  4905 
  4906 * more default rewrite rules for quantifiers, union/intersection;
  4907 
  4908 * a new constant `arbitrary == @x.False';
  4909 
  4910 * HOLCF/IOA replaces old HOL/IOA;
  4911 
  4912 * HOLCF changes: derived all rules and arities
  4913   + axiomatic type classes instead of classes
  4914   + typedef instead of faking type definitions
  4915   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4916   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4917   + eliminated the types void, one, tr
  4918   + use unit lift and bool lift (with translations) instead of one and tr
  4919   + eliminated blift from Lift3.thy (use Def instead of blift)
  4920   all eliminated rules are derived as theorems --> no visible changes ;
  4921 
  4922 
  4923 *** ZF ***
  4924 
  4925 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4926 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4927 as ZF_cs addSIs [equalityI];
  4928 
  4929 
  4930 
  4931 New in Isabelle94-7 (November 96)
  4932 ---------------------------------
  4933 
  4934 * allowing negative levels (as offsets) in prlev and choplev;
  4935 
  4936 * super-linear speedup for large simplifications;
  4937 
  4938 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4939 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4940 FAIL); can suppress it using the command Delsimps (ex_simps @
  4941 all_simps); De Morgan laws are also now included, by default;
  4942 
  4943 * improved printing of ==>  :  ~:
  4944 
  4945 * new object-logic "Sequents" adds linear logic, while replacing LK
  4946 and Modal (thanks to Sara Kalvala);
  4947 
  4948 * HOL/Auth: correctness proofs for authentication protocols;
  4949 
  4950 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4951 examples on HOL/Auth);
  4952 
  4953 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4954 the rewriter and classical reasoner simultaneously;
  4955 
  4956 * function uresult no longer returns theorems in "standard" format;
  4957 regain previous version by: val uresult = standard o uresult;
  4958 
  4959 
  4960 
  4961 New in Isabelle94-6
  4962 -------------------
  4963 
  4964 * oracles -- these establish an interface between Isabelle and trusted
  4965 external reasoners, which may deliver results as theorems;
  4966 
  4967 * proof objects (in particular record all uses of oracles);
  4968 
  4969 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4970 
  4971 * "constdefs" section in theory files;
  4972 
  4973 * "primrec" section (HOL) no longer requires names;
  4974 
  4975 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4976 
  4977 
  4978 
  4979 New in Isabelle94-5
  4980 -------------------
  4981 
  4982 * reduced space requirements;
  4983 
  4984 * automatic HTML generation from theories;
  4985 
  4986 * theory files no longer require "..." (quotes) around most types;
  4987 
  4988 * new examples, including two proofs of the Church-Rosser theorem;
  4989 
  4990 * non-curried (1994) version of HOL is no longer distributed;
  4991 
  4992 
  4993 
  4994 New in Isabelle94-4
  4995 -------------------
  4996 
  4997 * greatly reduced space requirements;
  4998 
  4999 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5000 
  5001 * searchable theorem database (see the section "Retrieving theorems" on
  5002 page 8 of the Reference Manual);
  5003 
  5004 * new examples, including Grabczewski's monumental case study of the
  5005 Axiom of Choice;
  5006 
  5007 * The previous version of HOL renamed to Old_HOL;
  5008 
  5009 * The new version of HOL (previously called CHOL) uses a curried syntax
  5010 for functions.  Application looks like f a b instead of f(a,b);
  5011 
  5012 * Mutually recursive inductive definitions finally work in HOL;
  5013 
  5014 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5015 translates to the operator "split";
  5016 
  5017 
  5018 
  5019 New in Isabelle94-3
  5020 -------------------
  5021 
  5022 * new infix operator, addss, allowing the classical reasoner to
  5023 perform simplification at each step of its search.  Example:
  5024         fast_tac (cs addss ss)
  5025 
  5026 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5027 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5028 look like (a,b) instead of <a,b>;
  5029 
  5030 * PLEASE NOTE: CHOL will eventually replace HOL!
  5031 
  5032 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5033 It translates to the operator "split".  A new theory of integers is available;
  5034 
  5035 * In ZF, integer numerals now denote two's-complement binary integers.
  5036 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5037 
  5038 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5039 of the Axiom of Choice;
  5040 
  5041 
  5042 
  5043 New in Isabelle94-2
  5044 -------------------
  5045 
  5046 * Significantly faster resolution;
  5047 
  5048 * the different sections in a .thy file can now be mixed and repeated
  5049 freely;
  5050 
  5051 * Database of theorems for FOL, HOL and ZF.  New
  5052 commands including qed, qed_goal and bind_thm store theorems in the database.
  5053 
  5054 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5055 a given theory (thms_of), or find out what theory a theorem was proved in
  5056 (theory_of_thm);
  5057 
  5058 * Bugs fixed in the inductive definition and datatype packages;
  5059 
  5060 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5061 and HOL_dup_cs obsolete;
  5062 
  5063 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5064 have been removed;
  5065 
  5066 * Simpler definition of function space in ZF;
  5067 
  5068 * new results about cardinal and ordinal arithmetic in ZF;
  5069 
  5070 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5071 types;
  5072 
  5073 :mode=text:wrap=hard:maxLineLen=72:
  5074 $Id$