NEWS
author wenzelm
Mon Oct 01 21:19:50 2007 +0200 (2007-10-01)
changeset 24803 38577b4b1fde
parent 24801 f53f6b08e13a
child 24804 513bb015b469
permissions -rw-r--r--
Norbert Schirmer: record improvements;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2007
     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
    47 no longer maintains dependencies on such files.
    48 
    49 * Syntax: the scope for resolving ambiguities via type-inference is
    50 now 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
   104 referred to by usual term syntax (including optional type
   105 annotations).
   106 
   107 * Code generator: basic definitions (from 'definition', 'constdefs',
   108 or primitive 'instance' definitions) are added automatically to the
   109 table of defining equations.  Primitive defs are not used as defining
   110 equations by default any longer.  defining equations are now definitly
   111 restricted to meta "==" and object equality "=".
   112 
   113 * The 'class' package offers a combination of axclass and locale to
   114 achieve Haskell-like type classes in Isabelle.  See
   115 HOL/ex/Classpackage.thy for examples.
   116 
   117 * Yet another code generator framework allows to generate executable
   118 code for ML and Haskell (including Isabelle classes).  A short usage
   119 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 For example usage see HOL/ex/Codegenerator.thy and
   158 HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   159 generation from Isabelle/HOL theories is available via "isatool doc
   160 codegen".
   161 
   162 * Command 'no_translations' removes translation rules from theory
   163 syntax.
   164 
   165 * Overloaded definitions are now actually checked for acyclic
   166 dependencies.  The overloading scheme is slightly more general than
   167 that of Haskell98, although Isabelle does not demand an exact
   168 correspondence to type class and instance declarations.
   169 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   170 exotic versions of overloading -- at the discretion of the user!
   171 
   172 Polymorphic constants are represented via type arguments, i.e. the
   173 instantiation that matches an instance against the most general
   174 declaration given in the signature.  For example, with the declaration
   175 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   176 as c(nat).  Overloading is essentially simultaneous structural
   177 recursion over such type arguments.  Incomplete specification patterns
   178 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   179 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   180 Command 'print_theory' outputs the normalized system of recursive
   181 equations, see section "definitions".
   182 
   183 * Configuration options are maintained within the theory or proof
   184 context (with name and type bool/int/string), providing a very simple
   185 interface to a poor-man's version of general context data.  Tools may
   186 declare options in ML (e.g. using Attrib.config_int) and then refer to
   187 these values using Config.get etc.  Users may change options via an
   188 associated attribute of the same name.  This form of context
   189 declaration works particularly well with commands 'declare' or
   190 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   191 very easy to avoid global references, which would not observe Isar
   192 toplevel undo/redo and fail to work with multithreading.
   193 
   194 Various global ML references of Pure and HOL have been turned into
   195 configuration options:
   196 
   197   Unify.search_bound		unify_search_bound
   198   Unify.trace_bound		unify_trace_bound
   199   Unify.trace_simp		unify_trace_simp
   200   Unify.trace_types		unify_trace_types
   201   Simplifier.simp_depth_limit	simp_depth_limit
   202   Blast.depth_limit		blast_depth_limit
   203   DatatypeProp.dtK		datatype_distinctness_limit
   204   fast_arith_neq_limit  	fast_arith_neq_limit
   205   fast_arith_split_limit	fast_arith_split_limit
   206 
   207 * Named collections of theorems may be easily installed as context
   208 data using the functor NamedThmsFun (see also
   209 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   210 attributes; there is also a toplevel print command.  This facility is
   211 just a common case of general context data, which is the preferred way
   212 for anything more complex than just a list of facts in canonical
   213 order.
   214 
   215 * Isar: command 'declaration' augments a local theory by generic
   216 declaration functions written in ML.  This enables arbitrary content
   217 being added to the context, depending on a morphism that tells the
   218 difference of the original declaration context wrt. the application
   219 context encountered later on.
   220 
   221 * Isar: proper interfaces for simplification procedures.  Command
   222 'simproc_setup' declares named simprocs (with match patterns, and body
   223 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   224 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   225 
   226 * Isar: an extra pair of brackets around attribute declarations
   227 abbreviates a theorem reference involving an internal dummy fact,
   228 which will be ignored later --- only the effect of the attribute on
   229 the background context will persist.  This form of in-place
   230 declarations is particularly useful with commands like 'declare' and
   231 'using', for example ``have A using [[simproc a]] by simp''.
   232 
   233 * Isar: method "assumption" (and implicit closing of subproofs) now
   234 takes simple non-atomic goal assumptions into account: after applying
   235 an assumption as a rule the resulting subgoals are solved by atomic
   236 assumption steps.  This is particularly useful to finish 'obtain'
   237 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   238 without referring to the original premise "!!x. P x ==> thesis" in the
   239 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   240 more permissive.
   241 
   242 * Isar: implicit use of prems from the Isar proof context is
   243 considered a legacy feature.  Common applications like ``have A .''
   244 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   245 referencing facts explicitly here improves readability and
   246 maintainability of proof texts.
   247 
   248 * Isar: improper proof element 'guess' is like 'obtain', but derives
   249 the obtained context from the course of reasoning!  For example:
   250 
   251   assume "EX x y. A x & B y"   -- "any previous fact"
   252   then guess x and y by clarify
   253 
   254 This technique is potentially adventurous, depending on the facts and
   255 proof tools being involved here.
   256 
   257 * Isar: known facts from the proof context may be specified as literal
   258 propositions, using ASCII back-quote syntax.  This works wherever
   259 named facts used to be allowed so far, in proof commands, proof
   260 methods, attributes etc.  Literal facts are retrieved from the context
   261 according to unification of type and term parameters.  For example,
   262 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   263 theorems in the current context, then these are valid literal facts:
   264 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   265 
   266 There is also a proof method "fact" which does the same composition
   267 for explicit goal states, e.g. the following proof texts coincide with
   268 certain special cases of literal facts:
   269 
   270   have "A" by fact                 ==  note `A`
   271   have "A ==> B" by fact           ==  note `A ==> B`
   272   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   273   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   274 
   275 * Isar: ":" (colon) is no longer a symbolic identifier character in
   276 outer syntax.  Thus symbolic identifiers may be used without
   277 additional white space in declarations like this: ``assume *: A''.
   278 
   279 * Isar: 'print_facts' prints all local facts of the current context,
   280 both named and unnamed ones.
   281 
   282 * Isar: 'def' now admits simultaneous definitions, e.g.:
   283 
   284   def x == "t" and y == "u"
   285 
   286 * Isar: added command 'unfolding', which is structurally similar to
   287 'using', but affects both the goal state and facts by unfolding given
   288 rewrite rules.  Thus many occurrences of the 'unfold' method or
   289 'unfolded' attribute may be replaced by first-class proof text.
   290 
   291 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   292 and command 'unfolding' now all support object-level equalities
   293 (potentially conditional).  The underlying notion of rewrite rule is
   294 analogous to the 'rule_format' attribute, but *not* that of the
   295 Simplifier (which is usually more generous).
   296 
   297 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   298 premises of a theorem by n. Useful in conjunction with drule.
   299 
   300 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   301 method expression within a sandbox consisting of the first N
   302 sub-goals, which need to exist.  For example, ``simp_all [3]''
   303 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   304 simplifies all new goals that emerge from applying rule foo to the
   305 originally first one.
   306 
   307 * Isar: schematic goals are no longer restricted to higher-order
   308 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   309 expected.
   310 
   311 * Isar: the conclusion of a long theorem statement is now either
   312 'shows' (a simultaneous conjunction, as before), or 'obtains'
   313 (essentially a disjunction of cases with local parameters and
   314 assumptions).  The latter allows to express general elimination rules
   315 adequately; in this notation common elimination rules look like this:
   316 
   317   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   318     assumes "EX x. P x"
   319     obtains x where "P x"
   320 
   321   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   322     assumes "A & B"
   323     obtains A and B
   324 
   325   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   326     assumes "A | B"
   327     obtains
   328       A
   329     | B
   330 
   331 The subsequent classical rules even refer to the formal "thesis"
   332 explicitly:
   333 
   334   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   335     obtains "~ thesis"
   336 
   337   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   338     obtains "thesis ==> something"
   339 
   340 The actual proof of an 'obtains' statement is analogous to that of the
   341 Isar proof element 'obtain', only that there may be several cases.
   342 Optional case names may be specified in parentheses; these will be
   343 available both in the present proof and as annotations in the
   344 resulting rule, for later use with the 'cases' method (cf. attribute
   345 case_names).
   346 
   347 * Isar: the assumptions of a long theorem statement are available as
   348 "assms" fact in the proof context.  This is more appropriate than the
   349 (historical) "prems", which refers to all assumptions of the current
   350 context, including those from the target locale, proof body etc.
   351 
   352 * Isar: 'print_statement' prints theorems from the current theory or
   353 proof context in long statement form, according to the syntax of a
   354 top-level lemma.
   355 
   356 * Isar: 'obtain' takes an optional case name for the local context
   357 introduction rule (default "that").
   358 
   359 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   360 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   361 to occur.
   362 
   363 * Pure: syntax "CONST name" produces a fully internalized constant
   364 according to the current context.  This is particularly useful for
   365 syntax translations that should refer to internal constant
   366 representations independently of name spaces.
   367 
   368 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   369 instead of "FOO ". This allows multiple binder declarations to coexist
   370 in the same context.  INCOMPATIBILITY.
   371 
   372 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   373 primitive that also works in a locale context (both for constants and
   374 fixed variables).  Type declaration and internal syntactic
   375 representation of given constants retrieved from the context.
   376 
   377 * Isar/locales: new derived specification elements 'axiomatization',
   378 'definition', 'abbreviation', which support type-inference, admit
   379 object-level specifications (equality, equivalence).  See also the
   380 isar-ref manual.  Examples:
   381 
   382   axiomatization
   383     eq  (infix "===" 50) where
   384     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   385 
   386   definition "f x y = x + y + 1"
   387   definition g where "g x = f x x"
   388 
   389   abbreviation
   390     neq  (infix "=!=" 50) where
   391     "x =!= y == ~ (x === y)"
   392 
   393 These specifications may be also used in a locale context.  Then the
   394 constants being introduced depend on certain fixed parameters, and the
   395 constant name is qualified by the locale base name.  An internal
   396 abbreviation takes care for convenient input and output, making the
   397 parameters implicit and using the original short name.  See also
   398 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   399 entities from a monomorphic theory.
   400 
   401 Presently, abbreviations are only available 'in' a target locale, but
   402 not inherited by general import expressions.  Also note that
   403 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   404 'translations' in common applications.  The "no_abbrevs" print mode
   405 prevents folding of abbreviations in term output.
   406 
   407 Concrete syntax is attached to specified constants in internal form,
   408 independently of name spaces.  The parse tree representation is
   409 slightly different -- use 'notation' instead of raw 'syntax', and
   410 'translations' with explicit "CONST" markup to accommodate this.
   411 
   412 * Pure/Isar: unified syntax for new-style specification mechanisms
   413 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   414 full type inference and dummy patterns ("_").  For example:
   415 
   416   definition "K x _ = x"
   417 
   418   inductive conj for A B
   419   where "A ==> B ==> conj A B"
   420 
   421 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   422 the current context.  Print mode "no_abbrevs" prevents inversion of
   423 abbreviations on output.
   424 
   425 * Isar/locales: improved parameter handling: use of locales "var" and
   426 "struct" no longer necessary; - parameter renamings are no longer
   427 required to be injective.  For example, this allows to define
   428 endomorphisms as locale endom = homom mult mult h.
   429 
   430 * Isar/locales: changed the way locales with predicates are defined.
   431 Instead of accumulating the specification, the imported expression is
   432 now an interpretation.  INCOMPATIBILITY: different normal form of
   433 locale expressions.  In particular, in interpretations of locales with
   434 predicates, goals repesenting already interpreted fragments are not
   435 removed automatically.  Use methods `intro_locales' and
   436 `unfold_locales'; see below.
   437 
   438 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   439 provide backward reasoning on locales predicates.  The methods are
   440 aware of interpretations and discharge corresponding goals.
   441 `intro_locales' is less aggressive then `unfold_locales' and does not
   442 unfold predicates to assumptions.
   443 
   444 * Isar/locales: the order in which locale fragments are accumulated
   445 has changed.  This enables to override declarations from fragments due
   446 to interpretations -- for example, unwanted simp rules.
   447 
   448 * Isar/locales: interpretation in theories and proof contexts has been
   449 extended.  One may now specify (and prove) equations, which are
   450 unfolded in interpreted theorems.  This is useful for replacing
   451 defined concepts (constants depending on locale parameters) by
   452 concepts already existing in the target context.  Example:
   453 
   454   interpretation partial_order ["op <= :: [int, int] => bool"]
   455     where "partial_order.less (op <=) (x::int) y = (x < y)"
   456 
   457 Typically, the constant `partial_order.less' is created by a
   458 definition specification element in the context of locale
   459 partial_order.
   460 
   461 * Provers/induct: improved internal context management to support
   462 local fixes and defines on-the-fly. Thus explicit meta-level
   463 connectives !!  and ==> are rarely required anymore in inductive goals
   464 (using object-logic connectives for this purpose has been long
   465 obsolete anyway). Common proof patterns are explained in
   466 HOL/Induct/Common_Patterns.thy, see also HOL/Isar_examples/Puzzle.thy
   467 and src/HOL/Lambda for realistic examples.
   468 
   469 * Provers/induct: improved handling of simultaneous goals. Instead of
   470 introducing object-level conjunction, the statement is now split into
   471 several conclusions, while the corresponding symbolic cases are nested
   472 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   473 see HOL/Induct/Common_Patterns.thy, for example.
   474 
   475 * Provers/induct: mutual induction rules are now specified as a list
   476 of rule sharing the same induction cases. HOL packages usually provide
   477 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   478 sets or datatypes). INCOMPATIBILITY, users need to specify mutual
   479 induction rules differently, i.e. like this:
   480 
   481   (induct rule: foo_bar.inducts)
   482   (induct set: foo bar)
   483   (induct type: foo bar)
   484 
   485 The ML function ProjectRule.projections turns old-style rules into the
   486 new format.
   487 
   488 * Provers/induct: support coinduction as well. See
   489 src/HOL/Library/Coinductive_List.thy for various examples.
   490 
   491 * Attribute "symmetric" produces result with standardized schematic
   492 variables (index 0).  Potential INCOMPATIBILITY.
   493 
   494 * Simplifier: by default the simplifier trace only shows top level
   495 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   496 default. Thus there is less danger of being flooded by the trace. The
   497 trace indicates where parts have been suppressed.
   498   
   499 * Provers/classical: removed obsolete classical version of elim_format
   500 attribute; classical elim/dest rules are now treated uniformly when
   501 manipulating the claset.
   502 
   503 * Provers/classical: stricter checks to ensure that supplied intro,
   504 dest and elim rules are well-formed; dest and elim rules must have at
   505 least one premise.
   506 
   507 * Provers/classical: attributes dest/elim/intro take an optional
   508 weight argument for the rule (just as the Pure versions).  Weights are
   509 ignored by automated tools, but determine the search order of single
   510 rule steps.
   511 
   512 * Syntax: input syntax now supports dummy variable binding "%_. b",
   513 where the body does not mention the bound variable.  Note that dummy
   514 patterns implicitly depend on their context of bounds, which makes
   515 "{_. _}" match any set comprehension as expected.  Potential
   516 INCOMPATIBILITY -- parse translations need to cope with syntactic
   517 constant "_idtdummy" in the binding position.
   518 
   519 * Syntax: removed obsolete syntactic constant "_K" and its associated
   520 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   521 for example "A -> B" => "Pi A (%_. B)".
   522 
   523 * Pure: 'class_deps' command visualizes the subclass relation, using
   524 the graph browser tool.
   525 
   526 * Pure: 'print_theory' now suppresses certain internal declarations by
   527 default; use '!' option for full details.
   528 
   529 
   530 *** HOL ***
   531 
   532 * Internal reorganisation of `size' of datatypes: size theorems
   533 "foo.size" are no longer subsumed by "foo.simps" (but are still
   534 simplification rules by default!); theorems "prod.size" now named
   535 "*.size"
   536 
   537 * The transitivity reasoner for partial and linear orders is set up
   538 for locales "order" and "linorder" generated by the new class package
   539 (instead of axiomatic type classes used before).  Instances of the
   540 reasoner are available in all contexts importing or interpreting these
   541 locales.  Method "order" invokes the reasoner separately; the reasoner
   542 is also integrated with the Simplifier as a solver.  Diagnostic
   543 command 'print_orders' shows the available instances of the reasoner
   544 in the current context.
   545 
   546 * Formulation of theorem "dense" changed slightly due to integration
   547 with new class dense_linear_order.
   548 
   549 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   550 Linorder etc.  have disappeared; operations defined in terms of
   551 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   552 
   553 * HOL-Word: New extensive library and type for generic, fixed size
   554 machine words, with arithemtic, bit-wise, shifting and rotating
   555 operations, reflection into int, nat, and bool lists, automation for
   556 linear arithmetic (by automatic reflection into nat or int), including
   557 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   558 arithmetic type classes, supporting automatic simplification of
   559 numerals on all operations.
   560 
   561 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   562 
   563 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   564 
   565 * Code generator library theories:
   566   - Pretty_Int represents HOL integers by big integer literals in target
   567     languages.
   568   - Pretty_Char represents HOL characters by character literals in target
   569     languages.
   570   - Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   571     codes; includes Pretty_Int.
   572   - Executable_Set allows to generate code for finite sets using lists.
   573   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   574     denominator).
   575   - Executable_Real implements a subset of real numbers, namly those
   576     representable by rational numbers.
   577   - Efficient_Nat implements natural numbers by integers, which in general will
   578     result in higher efficency; pattern matching with 0/Suc is eliminated;
   579     includes Pretty_Int.
   580   - ML_String provides an additional datatype ml_string; in the HOL default
   581     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   582     of type ml_string are mapped to strings in SML.
   583   - ML_Int provides an additional datatype ml_int which is mapped to to SML
   584     built-in integers.
   585 
   586 * New package for inductive predicates
   587 
   588   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   589 
   590     inductive
   591       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   592       for z_1 :: U_1 and ... and z_n :: U_m
   593     where
   594       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   595     | ...
   596 
   597   with full support for type-inference, rather than
   598 
   599     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   600 
   601     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   602     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   603 
   604     inductive "s z_1 ... z_m"
   605     intros
   606       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   607       ...
   608 
   609   For backward compatibility, there is a wrapper allowing inductive
   610   sets to be defined with the new package via
   611 
   612     inductive_set
   613       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   614       for z_1 :: U_1 and ... and z_n :: U_m
   615     where
   616       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   617     | ...
   618 
   619   or
   620 
   621     inductive_set
   622       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   623       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   624       for z_1 :: U_1 and ... and z_n :: U_m
   625     where
   626       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   627     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   628     | ...
   629 
   630   if the additional syntax "p ..." is required.
   631 
   632   Numerous examples can be found in the subdirectories HOL/Auth, HOL/Bali,
   633   HOL/Induct, and HOL/MicroJava.
   634 
   635   INCOMPATIBILITIES:
   636 
   637   - Since declaration and definition of inductive sets or predicates
   638     is no longer separated, abbreviations involving the newly
   639     introduced sets or predicates must be specified together with the
   640     introduction rules after the 'where' keyword (see above), rather
   641     than before the actual inductive definition.
   642 
   643   - The variables in induction and elimination rules are now
   644     quantified in the order of their occurrence in the introduction
   645     rules, rather than in alphabetical order. Since this may break
   646     some proofs, these proofs either have to be repaired, e.g. by
   647     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
   648     statements of the form
   649 
   650       case (rule_i a_i_1 ... a_i_{k_i})
   651 
   652     or the old order of quantification has to be restored by explicitly adding
   653     meta-level quantifiers in the introduction rules, i.e.
   654 
   655       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   656 
   657   - The format of the elimination rules is now
   658 
   659       p z_1 ... z_m x_1 ... x_n ==>
   660         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   661         ==> ... ==> P
   662 
   663     for predicates and
   664 
   665       (x_1, ..., x_n) : s z_1 ... z_m ==>
   666         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   667         ==> ... ==> P
   668 
   669     for sets rather than
   670 
   671       x : s z_1 ... z_m ==>
   672         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   673         ==> ... ==> P
   674 
   675     This may require terms in goals to be expanded to n-tuples
   676     (e.g. using case_tac or simplification with the split_paired_all
   677     rule) before the above elimination rule is applicable.
   678 
   679   - The elimination or case analysis rules for (mutually) inductive
   680     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
   681     list of rules "p_1_..._p_k.elims" is no longer available.
   682 
   683 * Method "metis" proves goals by applying the Metis general-purpose
   684 resolution prover.  Examples are in the directory MetisExamples.  See
   685 also http://gilith.com/software/metis/
   686 
   687 WARNING: the Isabelle/HOL-Metis integration does not yet work properly
   688 with multi-threading.
   689   
   690 * Command 'sledgehammer' invokes external automatic theorem provers as
   691 background processes.  It generates calls to the "metis" method if
   692 successful. These can be pasted into the proof.  Users do not have to
   693 wait for the automatic provers to return.
   694 
   695 * Case-expressions allow arbitrary constructor-patterns (including
   696 "_") and take their order into account, like in functional
   697 programming.  Internally, this is translated into nested
   698 case-expressions; missing cases are added and mapped to the predefined
   699 constant "undefined". In complicated cases printing may no longer show
   700 the original input but the internal form. Lambda-abstractions allow
   701 the same form of pattern matching: "% pat1 => e1 | ..." is an
   702 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
   703 variable.
   704 
   705 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   706 is an abbreviation for "of_nat :: nat => int". The simplification
   707 rules for "of_nat" have been changed to work like "int" did
   708 previously.  Potential INCOMPATIBILITY:
   709   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   710   - of_nat_diff and of_nat_mult are no longer default simp rules
   711 
   712 * Method "algebra" solves polynomial equations over (semi)rings using
   713 Groebner bases. The (semi)ring structure is defined by locales and the
   714 tool setup depends on that generic context. Installing the method for
   715 a specific type involves instantiating the locale and possibly adding
   716 declarations for computation on the coefficients.  The method is
   717 already instantiated for natural numbers and for the axiomatic class
   718 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
   719 CALCULEMUS 2007 for the general principles underlying this
   720 architecture of context-aware proof-tools.
   721 
   722 * Former constant "List.op @" now named "List.append".  Use ML
   723 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
   724 circumvent possible incompatibilities when working on ML level.
   725 
   726 * Some renaming of class constants due to canonical name prefixing in
   727 the new 'class' package:
   728 
   729     HOL.abs ~> HOL.minus_class.abs
   730     HOL.divide ~> HOL.divide_class.divide
   731     Nat.power ~> Nat.power_class.power
   732     Nat.size ~> Nat.size_class.size
   733     Numeral.number_of ~> Numeral.number_class.number_of
   734     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   735     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   736     Orderings.min ~> Orderings.ord_class.min
   737     Orderings.max ~> Orderings.ord_class.max
   738 
   739 * New class "default" with associated constant "default".
   740 
   741 * New constant "undefined" with axiom "undefined x = undefined".
   742 
   743 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   744 
   745 * New function listsum :: 'a list => 'a for arbitrary monoids.
   746 Special syntax: "SUM x <- xs. f x" (and latex variants)
   747 
   748 * New syntax for Haskell-like list comprehension (input only), eg.
   749 [(x,y). x <- xs, y <- ys, x ~= y], see also HOL/List.thy.
   750 
   751 * The special syntax for function "filter" has changed from [x :
   752 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
   753 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
   754 
   755 * [a..b] is now defined for arbitrary linear orders.  It used to be
   756 defined on nat only, as an abbreviation for [a..<Suc b]
   757 INCOMPATIBILITY.
   758 
   759 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
   760 
   761 * New functions "sorted" and "sort" in HOL/List.thy.
   762 
   763 * Function "sgn" is now overloaded and available on int, real, complex
   764 (and other numeric types), using class "sgn".  Two possible defs of
   765 sgn are given as equational assumptions in the classes sgn_if and
   766 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   767 INCOMPATIBILITY.
   768 
   769 * New lemma collection field_simps (an extension of ring_simps) for
   770 manipulating (in)equations involving division. Multiplies with all
   771 denominators that can be proved to be non-zero (in equations) or
   772 positive/negative (in inequations).
   773 
   774 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   775 have been improved and renamed to ring_simps, group_simps and
   776 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
   777 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
   778 
   779 * Library/Pretty_Int.thy: maps HOL numerals on target language integer
   780 literals when generating code.
   781 
   782 * Library/Pretty_Char.thy: maps HOL characters on target language
   783 character literals when generating code.
   784 
   785 * Library/Commutative_Ring.thy: switched from recdef to function
   786 package; constants add, mul, pow now curried.  Infix syntax for
   787 algebraic operations.
   788 
   789 * Some steps towards more uniform lattice theory development in HOL.
   790 
   791     constants "meet" and "join" now named "inf" and "sup"
   792     constant "Meet" now named "Inf"
   793 
   794     classes "meet_semilorder" and "join_semilorder" now named
   795       "lower_semilattice" and "upper_semilattice"
   796     class "lorder" now named "lattice"
   797     class "comp_lat" now named "complete_lattice"
   798 
   799     Instantiation of lattice classes allows explicit definitions
   800     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   801 
   802   INCOMPATIBILITY.  Theorem renames:
   803 
   804     meet_left_le            ~> inf_le1
   805     meet_right_le           ~> inf_le2
   806     join_left_le            ~> sup_ge1
   807     join_right_le           ~> sup_ge2
   808     meet_join_le            ~> inf_sup_ord
   809     le_meetI                ~> le_infI
   810     join_leI                ~> le_supI
   811     le_meet                 ~> le_inf_iff
   812     le_join                 ~> ge_sup_conv
   813     meet_idempotent         ~> inf_idem
   814     join_idempotent         ~> sup_idem
   815     meet_comm               ~> inf_commute
   816     join_comm               ~> sup_commute
   817     meet_leI1               ~> le_infI1
   818     meet_leI2               ~> le_infI2
   819     le_joinI1               ~> le_supI1
   820     le_joinI2               ~> le_supI2
   821     meet_assoc              ~> inf_assoc
   822     join_assoc              ~> sup_assoc
   823     meet_left_comm          ~> inf_left_commute
   824     meet_left_idempotent    ~> inf_left_idem
   825     join_left_comm          ~> sup_left_commute
   826     join_left_idempotent    ~> sup_left_idem
   827     meet_aci                ~> inf_aci
   828     join_aci                ~> sup_aci
   829     le_def_meet             ~> le_iff_inf
   830     le_def_join             ~> le_iff_sup
   831     join_absorp2            ~> sup_absorb2
   832     join_absorp1            ~> sup_absorb1
   833     meet_absorp1            ~> inf_absorb1
   834     meet_absorp2            ~> inf_absorb2
   835     meet_join_absorp        ~> inf_sup_absorb
   836     join_meet_absorp        ~> sup_inf_absorb
   837     distrib_join_le         ~> distrib_sup_le
   838     distrib_meet_le         ~> distrib_inf_le
   839 
   840     add_meet_distrib_left   ~> add_inf_distrib_left
   841     add_join_distrib_left   ~> add_sup_distrib_left
   842     is_join_neg_meet        ~> is_join_neg_inf
   843     is_meet_neg_join        ~> is_meet_neg_sup
   844     add_meet_distrib_right  ~> add_inf_distrib_right
   845     add_join_distrib_right  ~> add_sup_distrib_right
   846     add_meet_join_distribs  ~> add_sup_inf_distribs
   847     join_eq_neg_meet        ~> sup_eq_neg_inf
   848     meet_eq_neg_join        ~> inf_eq_neg_sup
   849     add_eq_meet_join        ~> add_eq_inf_sup
   850     meet_0_imp_0            ~> inf_0_imp_0
   851     join_0_imp_0            ~> sup_0_imp_0
   852     meet_0_eq_0             ~> inf_0_eq_0
   853     join_0_eq_0             ~> sup_0_eq_0
   854     neg_meet_eq_join        ~> neg_inf_eq_sup
   855     neg_join_eq_meet        ~> neg_sup_eq_inf
   856     join_eq_if              ~> sup_eq_if
   857 
   858     mono_meet               ~> mono_inf
   859     mono_join               ~> mono_sup
   860     meet_bool_eq            ~> inf_bool_eq
   861     join_bool_eq            ~> sup_bool_eq
   862     meet_fun_eq             ~> inf_fun_eq
   863     join_fun_eq             ~> sup_fun_eq
   864     meet_set_eq             ~> inf_set_eq
   865     join_set_eq             ~> sup_set_eq
   866     meet1_iff               ~> inf1_iff
   867     meet2_iff               ~> inf2_iff
   868     meet1I                  ~> inf1I
   869     meet2I                  ~> inf2I
   870     meet1D1                 ~> inf1D1
   871     meet2D1                 ~> inf2D1
   872     meet1D2                 ~> inf1D2
   873     meet2D2                 ~> inf2D2
   874     meet1E                  ~> inf1E
   875     meet2E                  ~> inf2E
   876     join1_iff               ~> sup1_iff
   877     join2_iff               ~> sup2_iff
   878     join1I1                 ~> sup1I1
   879     join2I1                 ~> sup2I1
   880     join1I1                 ~> sup1I1
   881     join2I2                 ~> sup1I2
   882     join1CI                 ~> sup1CI
   883     join2CI                 ~> sup2CI
   884     join1E                  ~> sup1E
   885     join2E                  ~> sup2E
   886 
   887     is_meet_Meet            ~> is_meet_Inf
   888     Meet_bool_def           ~> Inf_bool_def
   889     Meet_fun_def            ~> Inf_fun_def
   890     Meet_greatest           ~> Inf_greatest
   891     Meet_lower              ~> Inf_lower
   892     Meet_set_def            ~> Inf_set_def
   893 
   894     Sup_def                 ~> Sup_Inf
   895     Sup_bool_eq             ~> Sup_bool_def
   896     Sup_fun_eq              ~> Sup_fun_def
   897     Sup_set_eq              ~> Sup_set_def
   898 
   899     listsp_meetI            ~> listsp_infI
   900     listsp_meet_eq          ~> listsp_inf_eq
   901 
   902     meet_min                ~> inf_min
   903     join_max                ~> sup_max
   904 
   905 * Renamed classes "order" and "linorder": facts "refl", "trans" and
   906 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   907 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   908 
   909 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   910 changed order of proof goals instance proofs.
   911 
   912 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
   913 INCOMPATIBILITY.
   914 
   915 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
   916 INCOMPATIBILITY.
   917 
   918 * Added syntactic class "size"; overloaded constant "size" now has
   919 type "'a::size ==> bool"
   920 
   921 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   922 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and
   923 "Divides.dvd". INCOMPATIBILITY.
   924 
   925 * Method "lexicographic_order" automatically synthesizes termination
   926 relations as lexicographic combinations of size measures -- 'function'
   927 package.
   928 
   929 * HOL/records: generalised field-update to take a function on the
   930 field rather than the new value: r(|A := x|) is translated to A_update
   931 (K x) r The K-combinator that is internally used is called K_record.
   932 INCOMPATIBILITY: Usage of the plain update functions has to be
   933 adapted.
   934  
   935 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
   936 * x = 0, which are required for a semiring.  Richer structures do not
   937 inherit from semiring_0 anymore, because this property is a theorem
   938 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
   939 there is more to prove, but this is mostly trivial.
   940 
   941 * Class "recpower" is generalized to arbitrary monoids, not just
   942 commutative semirings.  INCOMPATIBILITY: may need to incorporate
   943 commutativity or a semiring properties additionally.
   944 
   945 * Unified locale "partial_order" with class definition (cf. theory
   946 Orderings), added parameter "less".  INCOMPATIBILITY.
   947 
   948 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   949 INCOMPATIBILITY: translations containing list_all2 may go wrong,
   950 better use 'abbreviation'.
   951 
   952 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
   953 
   954 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to
   955 "HOL.one_class.one".  INCOMPATIBILITY.
   956 
   957 * Added class "HOL.eq", allowing for code generation with polymorphic
   958 equality.
   959 
   960 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   961 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
   962 significant changes for setting up numeral syntax for types:
   963   - New constants Numeral.pred and Numeral.succ instead
   964       of former Numeral.bin_pred and Numeral.bin_succ.
   965   - Use integer operations instead of bin_add, bin_mult and so on.
   966   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   967   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   968 
   969 See HOL/Integ/IntArith.thy for an example setup.
   970 
   971 * New top level command 'normal_form' computes the normal form of a
   972 term that may contain free variables.  For example ``normal_form
   973 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   974 suitable for heavy-duty computations because the functions are
   975 compiled to ML first.
   976 
   977 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   978 25 like -->); output depends on the "iff" print_mode, the default is
   979 "A = B" (with priority 50).
   980 
   981 * Renamed constants in HOL.thy and Orderings.thy:
   982     op +   ~> HOL.plus_class.plus
   983     op -   ~> HOL.minus_class.minus
   984     uminus ~> HOL.minus_class.uminus
   985     abs    ~> HOL.abs_class.abs
   986     op *   ~> HOL.times_class.times
   987     op <   ~> HOL.ord_class.less
   988     op <=  ~> HOL.ord_class.less_eq
   989 
   990 Adaptions may be required in the following cases:
   991 
   992 a) User-defined constants using any of the names "plus", "minus",
   993 "times", "less" or "less_eq". The standard syntax translations for
   994 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   995 names.
   996 
   997 b) Variables named "plus", "minus", "times", "less", "less_eq"
   998 INCOMPATIBILITY: use more specific names.
   999 
  1000 c) Permutative equations (e.g. "a + b = b + a")
  1001 Since the change of names also changes the order of terms, permutative
  1002 rewrite rules may get applied in a different order. Experience shows
  1003 that this is rarely the case (only two adaptions in the whole Isabelle
  1004 distribution).  INCOMPATIBILITY: rewrite proofs
  1005 
  1006 d) ML code directly refering to constant names
  1007 This in general only affects hand-written proof tactics, simprocs and
  1008 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1009 Consider using @{const_name} antiquotation.
  1010 
  1011 * Relations less (<) and less_eq (<=) are also available on type bool.
  1012 Modified syntax to disallow nesting without explicit parentheses,
  1013 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1014 INCOMPATIBILITY.
  1015 
  1016 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1017 
  1018 * Relation composition operator "op O" now has precedence 75 and binds
  1019 stronger than union and intersection. INCOMPATIBILITY.
  1020 
  1021 * The old set interval syntax "{m..n(}" (and relatives) has been
  1022 removed.  Use "{m..<n}" (and relatives) instead.
  1023 
  1024 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1025 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1026 ``declare [[simproc del: neq]]''.
  1027 
  1028 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1029 True/False.
  1030 
  1031 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1032 
  1033 * Theorem setsum_mult renamed to setsum_right_distrib.
  1034 
  1035 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1036 ``rule'' method.
  1037 
  1038 * Reimplemented methods "sat" and "satx", with several improvements:
  1039 goals no longer need to be stated as "<prems> ==> False", equivalences
  1040 (i.e. "=" on type bool) are handled, variable names of the form
  1041 "lit_<n>" are no longer reserved, significant speedup.
  1042 
  1043 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1044 zChaff is still supported as well.
  1045 
  1046 * 'inductive' and 'datatype': provide projections of mutual rules,
  1047 bundled as foo_bar.inducts;
  1048 
  1049 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1050 Library.
  1051 
  1052 * Library: moved theory Accessible_Part to main HOL.
  1053 
  1054 * Library: added theory Coinductive_List of potentially infinite lists
  1055 as greatest fixed-point.
  1056 
  1057 * Library: added theory AssocList which implements (finite) maps as
  1058 association lists.
  1059 
  1060 * Method "evaluation" solves goals (i.e. a boolean expression)
  1061 efficiently by compiling it to ML.  The goal is "proved" (via an
  1062 oracle) if it evaluates to True.
  1063 
  1064 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1065 also when invoked by the simplifier.  This results in the Simplifier
  1066 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1067 Configuration option fast_arith_split_limit=0 recovers the old
  1068 behavior.
  1069 
  1070 * Support for hex (0x20) and binary (0b1001) numerals.
  1071 
  1072 * New method: reify eqs (t), where eqs are equations for an
  1073 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1074 parameter, computes a term s::'b and a list xs::'a list and proves the
  1075 theorem I xs s = t. This is also known as reification or quoting. The
  1076 resulting theorem is applied to the subgoal to substitute t with I xs
  1077 s.  If t is omitted, the subgoal itself is reified.
  1078 
  1079 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1080 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1081 where f is supposed to be a computable function (in the sense of code
  1082 generattion). The method uses reify to compute s and xs as above then
  1083 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1084 r and finally gets the theorem t = r, which is again applied to the
  1085 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1086 
  1087 * Reflection: Automatic reification now handels binding, an example
  1088 is available in HOL/ex/ReflectionEx.thy
  1089 
  1090 
  1091 *** HOL-Complex ***
  1092 
  1093 * Hyperreal: Functions root and sqrt are now defined on negative real
  1094 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1095 Nonnegativity side conditions have been removed from many lemmas, so
  1096 that more subgoals may now be solved by simplification; potential
  1097 INCOMPATIBILITY.
  1098 
  1099 * Real: new type classes formalize real normed vector spaces and
  1100 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1101 and norm :: 'a => real.
  1102 
  1103 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1104 reals into other types. The overloaded constant Reals :: 'a set is now
  1105 defined as range of_real; potential INCOMPATIBILITY.
  1106 
  1107 * Real: proper support for ML code generation, including 'quickcheck'.
  1108 Reals are implemented as arbitrary precision rationals.
  1109 
  1110 * Hyperreal: Several constants that previously worked only for the
  1111 reals have been generalized, so they now work over arbitrary vector
  1112 spaces. Type annotations may need to be added in some cases; potential
  1113 INCOMPATIBILITY.
  1114 
  1115   Infinitesimal  :: ('a::real_normed_vector) star set
  1116   HFinite        :: ('a::real_normed_vector) star set
  1117   HInfinite      :: ('a::real_normed_vector) star set
  1118   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1119   monad          :: ('a::real_normed_vector) star => 'a star set
  1120   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1121   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1122   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1123   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1124   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1125   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1126   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1127   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1128   sgn            :: 'a::real_normed_vector => 'a
  1129   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1130 
  1131 * Complex: Some complex-specific constants are now abbreviations for
  1132 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1133 hnorm.  Other constants have been entirely removed in favor of the
  1134 polymorphic versions (INCOMPATIBILITY):
  1135 
  1136   approx        <-- capprox
  1137   HFinite       <-- CFinite
  1138   HInfinite     <-- CInfinite
  1139   Infinitesimal <-- CInfinitesimal
  1140   monad         <-- cmonad
  1141   galaxy        <-- cgalaxy
  1142   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1143   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1144   (ns)deriv     <-- (ns)cderiv
  1145 
  1146 
  1147 *** HOL-Algebra ***
  1148 
  1149 * Formalisation of ideals and the quotient construction over rings.
  1150 
  1151 * Order and lattice theory no longer based on records.
  1152 INCOMPATIBILITY.
  1153 
  1154 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1155 greatest_closed.  INCOMPATIBILITY.
  1156 
  1157 * Method algebra is now set up via an attribute.  For examples see
  1158 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1159 of algebraic structures.
  1160 
  1161 * Renamed theory CRing to Ring.
  1162 
  1163 
  1164 *** HOL-Nominal ***
  1165 
  1166 * Fully featured support for nominal datatypes (binding structures)
  1167 due to the HOL-Nominal logic.  See HOL/Nominal, HOL/Nominal/Examples,
  1168 and http://isabelle.in.tum.de/nominal/download.html
  1169 
  1170 
  1171 *** ML ***
  1172 
  1173 * ML basics: just one true type int, which coincides with IntInf.int
  1174 (even on SML/NJ).
  1175 
  1176 * ML within Isar: antiquotations allow to embed statically-checked
  1177 formal entities in the source, referring to the context available at
  1178 compile-time.  For example:
  1179 
  1180 ML {* @{typ "'a => 'b"} *}
  1181 ML {* @{term "%x. x"} *}
  1182 ML {* @{prop "x == y"} *}
  1183 ML {* @{ctyp "'a => 'b"} *}
  1184 ML {* @{cterm "%x. x"} *}
  1185 ML {* @{cprop "x == y"} *}
  1186 ML {* @{thm asm_rl} *}
  1187 ML {* @{thms asm_rl} *}
  1188 ML {* @{type_name c} *}
  1189 ML {* @{const_name c} *}
  1190 ML {* @{const_syntax c} *}
  1191 ML {* @{context} *}
  1192 ML {* @{theory} *}
  1193 ML {* @{theory Pure} *}
  1194 ML {* @{theory_ref} *}
  1195 ML {* @{theory_ref Pure} *}
  1196 ML {* @{simpset} *}
  1197 ML {* @{claset} *}
  1198 ML {* @{clasimpset} *}
  1199 
  1200 The same works for sources being ``used'' within an Isar context.
  1201 
  1202 * ML in Isar: improved error reporting; extra verbosity with
  1203 ML_Context.trace enabled.
  1204 
  1205 * Pure/General/table.ML: the join operations now works via exceptions
  1206 DUP/SAME instead of type option. This is simpler in simple cases, and
  1207 admits slightly more efficient complex applications.
  1208 
  1209 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1210 use Context.generic instead of just theory.
  1211 
  1212 * Pure: datatype Context.generic joins theory/Proof.context and
  1213 provides some facilities for code that works in either kind of
  1214 context, notably GenericDataFun for uniform theory and proof data.
  1215 
  1216 * Pure: simplified internal attribute type, which is now always
  1217 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1218 local (Proof.context) attributes have been discontinued, while
  1219 minimizing code duplication. Thm.rule_attribute and
  1220 Thm.declaration_attribute build canonical attributes; see also structure
  1221 Context for further operations on Context.generic, notably
  1222 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1223 declarations and definitions.
  1224 
  1225 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1226 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1227 init only required for impure data. INCOMPATIBILITY: empty really need
  1228 to be empty (no dependencies on theory content!)
  1229 
  1230 * Pure/kernel: consts certification ignores sort constraints given in
  1231 signature declarations. (This information is not relevant to the
  1232 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1233 potential INCOMPATIBILITY.
  1234 
  1235 * Pure: axiomatic type classes are now purely definitional, with
  1236 explicit proofs of class axioms and super class relations performed
  1237 internally. See Pure/axclass.ML for the main internal interfaces --
  1238 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1239 AxClass.axiomatize_class/classrel/arity supersede
  1240 Sign.add_classes/classrel/arities.
  1241 
  1242 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1243 global/local versions on theory vs. Proof.context have been
  1244 discontinued; Attrib.syntax and Method.syntax have been adapted
  1245 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1246 attributes, methods, etc.
  1247 
  1248 * Pure: several functions of signature "... -> theory -> theory * ..."
  1249 have been reoriented to "... -> theory -> ... * theory" in order to
  1250 allow natural usage in combination with the ||>, ||>>, |-> and
  1251 fold_map combinators.
  1252 
  1253 * Pure: official theorem names (closed derivations) and additional
  1254 comments (tags) are now strictly separate.  Name hints -- which are
  1255 maintained as tags -- may be attached any time without affecting the
  1256 derivation.
  1257 
  1258 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1259 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1260 achieve the old behaviour.
  1261 
  1262 * Pure: the "Goal" constant is now called "prop", supporting a
  1263 slightly more general idea of ``protecting'' meta-level rule
  1264 statements.
  1265 
  1266 * Pure: Logic.(un)varify only works in a global context, which is now
  1267 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1268 Logic.legacy_(un)varify as temporary workaround.
  1269 
  1270 * Pure: structure Name provides scalable operations for generating
  1271 internal variable names, notably Name.variants etc.  This replaces
  1272 some popular functions from term.ML:
  1273 
  1274   Term.variant		->  Name.variant
  1275   Term.variantlist	->  Name.variant_list
  1276   Term.invent_names	->  Name.invent_list
  1277 
  1278 Note that low-level renaming rarely occurs in new code -- operations
  1279 from structure Variable are used instead (see below).
  1280 
  1281 * Pure: structure Variable provides fundamental operations for proper
  1282 treatment of fixed/schematic variables in a context.  For example,
  1283 Variable.import introduces fixes for schematics of given facts and
  1284 Variable.export reverses the effect (up to renaming) -- this replaces
  1285 various freeze_thaw operations.
  1286 
  1287 * Pure: structure Goal provides simple interfaces for
  1288 init/conclude/finish and tactical prove operations (replacing former
  1289 Tactic.prove).  Goal.prove is the canonical way to prove results
  1290 within a given context; Goal.prove_global is a degraded version for
  1291 theory level goals, including a global Drule.standard.  Note that
  1292 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1293 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1294 in a locale context).
  1295 
  1296 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1297 and type checking (Syntax.check_term etc.), with common combinations
  1298 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1299 which are considered legacy and await removal.
  1300 
  1301 * Isar: simplified treatment of user-level errors, using exception
  1302 ERROR of string uniformly.  Function error now merely raises ERROR,
  1303 without any side effect on output channels.  The Isar toplevel takes
  1304 care of proper display of ERROR exceptions.  ML code may use plain
  1305 handle/can/try; cat_error may be used to concatenate errors like this:
  1306 
  1307   ... handle ERROR msg => cat_error msg "..."
  1308 
  1309 Toplevel ML code (run directly or through the Isar toplevel) may be
  1310 embedded into the Isar toplevel with exception display/debug like
  1311 this:
  1312 
  1313   Isar.toplevel (fn () => ...)
  1314 
  1315 INCOMPATIBILITY, removed special transform_error facilities, removed
  1316 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1317 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1318 -- use plain ERROR instead.
  1319 
  1320 * Isar: theory setup now has type (theory -> theory), instead of a
  1321 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1322 
  1323 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1324 ProofContext.debug/verbose flags.
  1325 
  1326 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1327 theory before entering a proof state.  Transactions now always see a
  1328 quasi-functional intermediate checkpoint, both in interactive and
  1329 batch mode.
  1330 
  1331 * Simplifier: the simpset of a running simplification process now
  1332 contains a proof context (cf. Simplifier.the_context), which is the
  1333 very context that the initial simpset has been retrieved from (by
  1334 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1335 (solver, looper etc.) may depend on arbitrary proof data.
  1336 
  1337 * Simplifier.inherit_context inherits the proof context (plus the
  1338 local bounds) of the current simplification process; any simproc
  1339 etc. that calls the Simplifier recursively should do this!  Removed
  1340 former Simplifier.inherit_bounds, which is already included here --
  1341 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1342 specify an explicit context using Simplifier.context/theory_context.
  1343 
  1344 * Simplifier/Classical Reasoner: more abstract interfaces
  1345 change_simpset/claset for modifying the simpset/claset reference of a
  1346 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1347 INCOMPATIBILITY.
  1348 
  1349 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1350 "Trueprop" etc.
  1351 
  1352 
  1353 *** System ***
  1354 
  1355 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1356 locations -- now includes the Isabelle version identifier as well.
  1357 This simplifies use of multiple Isabelle installations.
  1358 
  1359 * isabelle-process: option -S (secure mode) disables some critical
  1360 operations, notably runtime compilation and evaluation of ML source
  1361 code.
  1362 
  1363 * Support for parallel execution, using native multicore support of
  1364 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1365 independent theories, according to the given theory header
  1366 specifications. The maximum number of worker threads is specified via
  1367 usedir option -M or the "max-threads" setting in Proof General. A
  1368 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1369 to 6 on a 8-core machine.  User-code needs to observe certain
  1370 guidelines for thread-safe programming, see appendix A in the Isar
  1371 Implementation manual.
  1372 
  1373 
  1374 New in Isabelle2005 (October 2005)
  1375 ----------------------------------
  1376 
  1377 *** General ***
  1378 
  1379 * Theory headers: the new header syntax for Isar theories is
  1380 
  1381   theory <name>
  1382   imports <theory1> ... <theoryN>
  1383   uses <file1> ... <fileM>
  1384   begin
  1385 
  1386 where the 'uses' part is optional.  The previous syntax
  1387 
  1388   theory <name> = <theory1> + ... + <theoryN>:
  1389 
  1390 will disappear in the next release.  Use isatool fixheaders to convert
  1391 existing theory files.  Note that there is no change in ancient
  1392 non-Isar theories now, but these will disappear soon.
  1393 
  1394 * Theory loader: parent theories can now also be referred to via
  1395 relative and absolute paths.
  1396 
  1397 * Command 'find_theorems' searches for a list of criteria instead of a
  1398 list of constants. Known criteria are: intro, elim, dest, name:string,
  1399 simp:term, and any term. Criteria can be preceded by '-' to select
  1400 theorems that do not match. Intro, elim, dest select theorems that
  1401 match the current goal, name:s selects theorems whose fully qualified
  1402 name contain s, and simp:term selects all simplification rules whose
  1403 lhs match term.  Any other term is interpreted as pattern and selects
  1404 all theorems matching the pattern. Available in ProofGeneral under
  1405 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1406 
  1407   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1408 
  1409 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1410 matching the current goal as introduction rule and not having "HOL."
  1411 in their name (i.e. not being defined in theory HOL).
  1412 
  1413 * Command 'thms_containing' has been discontinued in favour of
  1414 'find_theorems'; INCOMPATIBILITY.
  1415 
  1416 * Communication with Proof General is now 8bit clean, which means that
  1417 Unicode text in UTF-8 encoding may be used within theory texts (both
  1418 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1419 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1420 
  1421   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1422   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1423 
  1424 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1425 Classical Reasoner.  Typical big applications run around 2 times
  1426 faster.
  1427 
  1428 
  1429 *** Document preparation ***
  1430 
  1431 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1432 of raw sources.  Only those symbols that do not require additional
  1433 LaTeX packages (depending on comments in isabellesym.sty) are
  1434 displayed properly, everything else is left verbatim.  isatool display
  1435 and isatool print are used as front ends (these are subject to the
  1436 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1437 
  1438 * Command tags control specific markup of certain regions of text,
  1439 notably folding and hiding.  Predefined tags include "theory" (for
  1440 theory begin and end), "proof" for proof commands, and "ML" for
  1441 commands involving ML code; the additional tags "visible" and
  1442 "invisible" are unused by default.  Users may give explicit tag
  1443 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1444 interpretation of tags is determined by the LaTeX job during document
  1445 preparation: see option -V of isatool usedir, or options -n and -t of
  1446 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1447 \isadroptag.
  1448 
  1449 Several document versions may be produced at the same time via isatool
  1450 usedir (the generated index.html will link all of them).  Typical
  1451 specifications include ''-V document=theory,proof,ML'' to present
  1452 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1453 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1454 these parts without any formal replacement text.  The Isabelle site
  1455 default settings produce ''document'' and ''outline'' versions as
  1456 specified above.
  1457 
  1458 * Several new antiquotations:
  1459 
  1460   @{term_type term} prints a term with its type annotated;
  1461 
  1462   @{typeof term} prints the type of a term;
  1463 
  1464   @{const const} is the same as @{term const}, but checks that the
  1465   argument is a known logical constant;
  1466 
  1467   @{term_style style term} and @{thm_style style thm} print a term or
  1468   theorem applying a "style" to it
  1469 
  1470   @{ML text}
  1471 
  1472 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1473 definitions, equations, inequations etc., 'concl' printing only the
  1474 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1475 to print the specified premise.  TermStyle.add_style provides an ML
  1476 interface for introducing further styles.  See also the "LaTeX Sugar"
  1477 document practical applications.  The ML antiquotation prints
  1478 type-checked ML expressions verbatim.
  1479 
  1480 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1481 and 'text' support optional locale specification '(in loc)', which
  1482 specifies the default context for interpreting antiquotations.  For
  1483 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1484 
  1485 * Option 'locale=NAME' of antiquotations specifies an alternative
  1486 context interpreting the subsequent argument.  For example: @{thm
  1487 [locale=lattice] inf_assoc}.
  1488 
  1489 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1490 a proof context.
  1491 
  1492 * Proper output of antiquotations for theory commands involving a
  1493 proof context (such as 'locale' or 'theorem (in loc) ...').
  1494 
  1495 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1496 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1497 
  1498 * isatool usedir: new option -C (default true) controls whether option
  1499 -D should include a copy of the original document directory; -C false
  1500 prevents unwanted effects such as copying of administrative CVS data.
  1501 
  1502 
  1503 *** Pure ***
  1504 
  1505 * Considerably improved version of 'constdefs' command.  Now performs
  1506 automatic type-inference of declared constants; additional support for
  1507 local structure declarations (cf. locales and HOL records), see also
  1508 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1509 sequential dependencies of definitions within a single 'constdefs'
  1510 section; moreover, the declared name needs to be an identifier.  If
  1511 all fails, consider to fall back on 'consts' and 'defs' separately.
  1512 
  1513 * Improved indexed syntax and implicit structures.  First of all,
  1514 indexed syntax provides a notational device for subscripted
  1515 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1516 expressions.  Secondly, in a local context with structure
  1517 declarations, number indexes \<^sub>n or the empty index (default
  1518 number 1) refer to a certain fixed variable implicitly; option
  1519 show_structs controls printing of implicit structures.  Typical
  1520 applications of these concepts involve record types and locales.
  1521 
  1522 * New command 'no_syntax' removes grammar declarations (and
  1523 translations) resulting from the given syntax specification, which is
  1524 interpreted in the same manner as for the 'syntax' command.
  1525 
  1526 * 'Advanced' translation functions (parse_translation etc.) may depend
  1527 on the signature of the theory context being presently used for
  1528 parsing/printing, see also isar-ref manual.
  1529 
  1530 * Improved 'oracle' command provides a type-safe interface to turn an
  1531 ML expression of type theory -> T -> term into a primitive rule of
  1532 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1533 is already included here); see also FOL/ex/IffExample.thy;
  1534 INCOMPATIBILITY.
  1535 
  1536 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1537 before); "cI" is no longer bound, use "c.intro" instead.
  1538 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1539 axclasses vs. locales.
  1540 
  1541 * Improved internal renaming of symbolic identifiers -- attach primes
  1542 instead of base 26 numbers.
  1543 
  1544 * New flag show_question_marks controls printing of leading question
  1545 marks in schematic variable names.
  1546 
  1547 * In schematic variable names, *any* symbol following \<^isub> or
  1548 \<^isup> is now treated as part of the base name.  For example, the
  1549 following works without printing of awkward ".0" indexes:
  1550 
  1551   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1552     by simp
  1553 
  1554 * Inner syntax includes (*(*nested*) comments*).
  1555 
  1556 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1557 annotations as "(00...)".
  1558 
  1559 * Clear separation of logical types and nonterminals, where the latter
  1560 may only occur in 'syntax' specifications or type abbreviations.
  1561 Before that distinction was only partially implemented via type class
  1562 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1563 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1564 exotic syntax specifications may require further adaption
  1565 (e.g. Cube/Cube.thy).
  1566 
  1567 * Removed obsolete type class "logic", use the top sort {} instead.
  1568 Note that non-logical types should be declared as 'nonterminals'
  1569 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1570 specifications.
  1571 
  1572 * Attributes 'induct' and 'cases': type or set names may now be
  1573 locally fixed variables as well.
  1574 
  1575 * Simplifier: can now control the depth to which conditional rewriting
  1576 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1577 Limit.
  1578 
  1579 * Simplifier: simplification procedures may now take the current
  1580 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1581 interface), which is very useful for calling the Simplifier
  1582 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1583 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1584 low-level mk_simproc no longer applies Logic.varify internally, to
  1585 allow for use in a context of fixed variables.
  1586 
  1587 * thin_tac now works even if the assumption being deleted contains !!
  1588 or ==>.  More generally, erule now works even if the major premise of
  1589 the elimination rule contains !! or ==>.
  1590 
  1591 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1592 
  1593 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1594 from Pure, which contains all common declarations already.  Both
  1595 theories are defined via plain Isabelle/Isar .thy files.
  1596 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1597 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1598 use isatool fixcpure to adapt your theory and ML sources.
  1599 
  1600 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1601 selections of theorems in named facts via index ranges.
  1602 
  1603 * 'print_theorems': in theory mode, really print the difference
  1604 wrt. the last state (works for interactive theory development only),
  1605 in proof mode print all local facts (cf. 'print_facts');
  1606 
  1607 * 'hide': option '(open)' hides only base names.
  1608 
  1609 * More efficient treatment of intermediate checkpoints in interactive
  1610 theory development.
  1611 
  1612 * Code generator is now invoked via code_module (incremental code
  1613 generation) and code_library (modular code generation, ML structures
  1614 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1615 must be quoted when used as identifiers.
  1616 
  1617 * New 'value' command for reading, evaluating and printing terms using
  1618 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1619 quoted when used as identifier.
  1620 
  1621 
  1622 *** Locales ***
  1623 
  1624 * New commands for the interpretation of locale expressions in
  1625 theories (1), locales (2) and proof contexts (3).  These generate
  1626 proof obligations from the expression specification.  After the
  1627 obligations have been discharged, theorems of the expression are added
  1628 to the theory, target locale or proof context.  The synopsis of the
  1629 commands is a follows:
  1630 
  1631   (1) interpretation expr inst
  1632   (2) interpretation target < expr
  1633   (3) interpret expr inst
  1634 
  1635 Interpretation in theories and proof contexts require a parameter
  1636 instantiation of terms from the current context.  This is applied to
  1637 specifications and theorems of the interpreted expression.
  1638 Interpretation in locales only permits parameter renaming through the
  1639 locale expression.  Interpretation is smart in that interpretations
  1640 that are active already do not occur in proof obligations, neither are
  1641 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1642 inspect active interpretations of a particular locale.  For details,
  1643 see the Isar Reference manual.  Examples can be found in
  1644 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1645 
  1646 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1647 'interpret' instead.
  1648 
  1649 * New context element 'constrains' for adding type constraints to
  1650 parameters.
  1651 
  1652 * Context expressions: renaming of parameters with syntax
  1653 redeclaration.
  1654 
  1655 * Locale declaration: 'includes' disallowed.
  1656 
  1657 * Proper static binding of attribute syntax -- i.e. types / terms /
  1658 facts mentioned as arguments are always those of the locale definition
  1659 context, independently of the context of later invocations.  Moreover,
  1660 locale operations (renaming and type / term instantiation) are applied
  1661 to attribute arguments as expected.
  1662 
  1663 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1664 actual attributes; rare situations may require Attrib.attribute to
  1665 embed those attributes into Attrib.src that lack concrete syntax.
  1666 Attribute implementations need to cooperate properly with the static
  1667 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1668 Attrib.XXX_thm etc. already do the right thing without further
  1669 intervention.  Only unusual applications -- such as "where" or "of"
  1670 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1671 on the context and the facts involved -- may have to assign parsed
  1672 values to argument tokens explicitly.
  1673 
  1674 * Changed parameter management in theorem generation for long goal
  1675 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1676 theorem statement in rare situations.
  1677 
  1678 * Locale inspection command 'print_locale' omits notes elements.  Use
  1679 'print_locale!' to have them included in the output.
  1680 
  1681 
  1682 *** Provers ***
  1683 
  1684 * Provers/hypsubst.ML: improved version of the subst method, for
  1685 single-step rewriting: it now works in bound variable contexts. New is
  1686 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1687 rewrite a different subterm than the original subst method, which is
  1688 still available as 'simplesubst'.
  1689 
  1690 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1691 and quasi orders.
  1692 
  1693 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1694 reflexive-transitive closure of relations.
  1695 
  1696 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1697 limit (previously hard-coded with a value of 20) user-definable.
  1698 
  1699 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1700 is peformed already.  Object-logics merely need to finish their
  1701 initial simpset configuration as before.  INCOMPATIBILITY.
  1702 
  1703 
  1704 *** HOL ***
  1705 
  1706 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1707 
  1708   syntax (epsilon)
  1709     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1710 
  1711 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1712 and x-symbol; use option '-m epsilon' to get it actually printed.
  1713 Moreover, the mathematically important symbolic identifier \<epsilon>
  1714 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1715 
  1716 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1717 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1718 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1719 support corresponding Isar calculations.
  1720 
  1721 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1722 instead of ":".
  1723 
  1724 * theory SetInterval: changed the syntax for open intervals:
  1725 
  1726   Old       New
  1727   {..n(}    {..<n}
  1728   {)n..}    {n<..}
  1729   {m..n(}   {m..<n}
  1730   {)m..n}   {m<..n}
  1731   {)m..n(}  {m<..<n}
  1732 
  1733 The old syntax is still supported but will disappear in the next
  1734 release.  For conversion use the following Emacs search and replace
  1735 patterns (these are not perfect but work quite well):
  1736 
  1737   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1738   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1739 
  1740 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1741 equalities in commutative rings; method 'algebra' provides a generic
  1742 interface.
  1743 
  1744 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1745 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1746 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1747 be a tuple pattern.
  1748 
  1749 Some new syntax forms are available:
  1750 
  1751   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1752   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1753   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1754   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1755 
  1756 The latter form "\<Sum>x < k. e" used to be based on a separate
  1757 function "Summation", which has been discontinued.
  1758 
  1759 * theory Finite_Set: in structured induction proofs, the insert case
  1760 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1761 (insert F x)'.
  1762 
  1763 * The 'refute' command has been extended to support a much larger
  1764 fragment of HOL, including axiomatic type classes, constdefs and
  1765 typedefs, inductive datatypes and recursion.
  1766 
  1767 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1768 Requires zChaff with proof generation to be installed.  See
  1769 HOL/ex/SAT_Examples.thy for examples.
  1770 
  1771 * Datatype induction via method 'induct' now preserves the name of the
  1772 induction variable. For example, when proving P(xs::'a list) by
  1773 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1774 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1775 in unstructured proof scripts.
  1776 
  1777 * Reworked implementation of records.  Improved scalability for
  1778 records with many fields, avoiding performance problems for type
  1779 inference. Records are no longer composed of nested field types, but
  1780 of nested extension types. Therefore the record type only grows linear
  1781 in the number of extensions and not in the number of fields.  The
  1782 top-level (users) view on records is preserved.  Potential
  1783 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1784 old record representation. The type generated for a record is called
  1785 <record_name>_ext_type.
  1786 
  1787 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1788 proofs triggered by a record definition or a simproc (if
  1789 quick_and_dirty is enabled).  Definitions of large records can take
  1790 quite long.
  1791 
  1792 New simproc record_upd_simproc for simplification of multiple record
  1793 updates enabled by default.  Moreover, trivial updates are also
  1794 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1795 occasionally, since simplification is more powerful by default.
  1796 
  1797 * typedef: proper support for polymorphic sets, which contain extra
  1798 type-variables in the term.
  1799 
  1800 * Simplifier: automatically reasons about transitivity chains
  1801 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1802 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1803 old proofs break occasionally as simplification may now solve more
  1804 goals than previously.
  1805 
  1806 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1807 present.  Works for all partial orders (class "order"), in particular
  1808 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1809 just like y <= x.
  1810 
  1811 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1812 bound variable or a constant then the let is unfolded.  Otherwise
  1813 first a is simplified to b, and then f b is simplified to g. If
  1814 possible we abstract b from g arriving at "let x = b in h x",
  1815 otherwise we unfold the let and arrive at g.  The simproc can be
  1816 enabled/disabled by the reference use_let_simproc.  Potential
  1817 INCOMPATIBILITY since simplification is more powerful by default.
  1818 
  1819 * Classical reasoning: the meson method now accepts theorems as arguments.
  1820 
  1821 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1822 jobs to provide advice on the provability of subgoals.
  1823 
  1824 * Theory OrderedGroup and Ring_and_Field: various additions and
  1825 improvements to faciliate calculations involving equalities and
  1826 inequalities.
  1827 
  1828 The following theorems have been eliminated or modified
  1829 (INCOMPATIBILITY):
  1830 
  1831   abs_eq             now named abs_of_nonneg
  1832   abs_of_ge_0        now named abs_of_nonneg
  1833   abs_minus_eq       now named abs_of_nonpos
  1834   imp_abs_id         now named abs_of_nonneg
  1835   imp_abs_neg_id     now named abs_of_nonpos
  1836   mult_pos           now named mult_pos_pos
  1837   mult_pos_le        now named mult_nonneg_nonneg
  1838   mult_pos_neg_le    now named mult_nonneg_nonpos
  1839   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1840   mult_neg           now named mult_neg_neg
  1841   mult_neg_le        now named mult_nonpos_nonpos
  1842 
  1843 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1844      
  1845      zero_le_square
  1846      not_square_less_zero 
  1847 
  1848   The following lemmas have been deleted from Real/RealPow:
  1849   
  1850      realpow_zero_zero
  1851      realpow_two
  1852      realpow_less
  1853      zero_le_power
  1854      realpow_two_le
  1855      abs_realpow_two
  1856      realpow_two_abs     
  1857 
  1858 * Theory Parity: added rules for simplifying exponents.
  1859 
  1860 * Theory List:
  1861 
  1862 The following theorems have been eliminated or modified
  1863 (INCOMPATIBILITY):
  1864 
  1865   list_all_Nil       now named list_all.simps(1)
  1866   list_all_Cons      now named list_all.simps(2)
  1867   list_all_conv      now named list_all_iff
  1868   set_mem_eq         now named mem_iff
  1869 
  1870 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1871 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1872 
  1873 
  1874 *** HOL-Complex ***
  1875 
  1876 * Theory RealDef: better support for embedding natural numbers and
  1877 integers in the reals.
  1878 
  1879 The following theorems have been eliminated or modified
  1880 (INCOMPATIBILITY):
  1881 
  1882   exp_ge_add_one_self  now requires no hypotheses
  1883   real_of_int_add      reversed direction of equality (use [symmetric])
  1884   real_of_int_minus    reversed direction of equality (use [symmetric])
  1885   real_of_int_diff     reversed direction of equality (use [symmetric])
  1886   real_of_int_mult     reversed direction of equality (use [symmetric])
  1887 
  1888 * Theory RComplete: expanded support for floor and ceiling functions.
  1889 
  1890 * Theory Ln is new, with properties of the natural logarithm
  1891 
  1892 * Hyperreal: There is a new type constructor "star" for making
  1893 nonstandard types.  The old type names are now type synonyms:
  1894 
  1895   hypreal = real star
  1896   hypnat = nat star
  1897   hcomplex = complex star
  1898 
  1899 * Hyperreal: Many groups of similarly-defined constants have been
  1900 replaced by polymorphic versions (INCOMPATIBILITY):
  1901 
  1902   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1903 
  1904   starset      <-- starsetNat, starsetC
  1905   *s*          <-- *sNat*, *sc*
  1906   starset_n    <-- starsetNat_n, starsetC_n
  1907   *sn*         <-- *sNatn*, *scn*
  1908   InternalSets <-- InternalNatSets, InternalCSets
  1909 
  1910   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1911   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1912   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1913   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1914   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1915 
  1916 * Hyperreal: Many type-specific theorems have been removed in favor of
  1917 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1918 
  1919   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1920   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1921   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1922   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1923   right_minus <-- hypreal_add_minus
  1924   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1925   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1926   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1927   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1928   mult_1_right <-- hcomplex_mult_one_right
  1929   mult_zero_left <-- hcomplex_mult_zero_left
  1930   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1931   right_distrib <-- hypnat_add_mult_distrib2
  1932   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1933   right_inverse <-- hypreal_mult_inverse
  1934   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1935   order_refl <-- {hypreal,hypnat}_le_refl
  1936   order_trans <-- {hypreal,hypnat}_le_trans
  1937   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1938   order_less_le <-- {hypreal,hypnat}_less_le
  1939   linorder_linear <-- {hypreal,hypnat}_le_linear
  1940   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1941   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1942   add_nonneg_nonneg <-- hypreal_le_add_order
  1943 
  1944 * Hyperreal: Separate theorems having to do with type-specific
  1945 versions of constants have been merged into theorems that apply to the
  1946 new polymorphic constants (INCOMPATIBILITY):
  1947 
  1948   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1949   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1950   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1951   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1952   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1953   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1954   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1955   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1956   STAR_diff <-- {STAR,STARC}_diff
  1957   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1958     STARC_hcomplex_of_complex}_image_subset
  1959   starset_n_Un <-- starset{Nat,C}_n_Un
  1960   starset_n_Int <-- starset{Nat,C}_n_Int
  1961   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1962   starset_n_diff <-- starset{Nat,C}_n_diff
  1963   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1964   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1965   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1966   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1967   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1968   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1969   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1970   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1971   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1972   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1973   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1974   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1975   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1976   starfun_diff <-- starfun{C,RC,CR}_diff
  1977   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1978   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1979   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1980   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1981   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1982   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1983   starfun_Id <-- starfunC_Id
  1984   starfun_approx <-- starfun{Nat,CR}_approx
  1985   starfun_capprox <-- starfun{C,RC}_capprox
  1986   starfun_abs <-- starfunNat_rabs
  1987   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1988   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1989   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1990   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1991   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1992   starfun_add_approx <-- starfunCR_add_approx
  1993   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1994   starfun_divide <-- starfun{C,CR,RC}_divide
  1995   starfun_n <-- starfun{Nat,C}_n
  1996   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1997   starfun_n_add <-- starfun{Nat,C}_n_add
  1998   starfun_n_add_minus <-- starfunNat_n_add_minus
  1999   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2000   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2001   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2002 
  2003   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2004   star_n_minus <-- {hypreal,hcomplex}_minus
  2005   star_n_diff <-- {hypreal,hcomplex}_diff
  2006   star_n_mult <-- {hypreal,hcomplex}_mult
  2007   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2008   star_n_le <-- {hypreal,hypnat}_le
  2009   star_n_less <-- {hypreal,hypnat}_less
  2010   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2011   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2012   star_n_abs <-- hypreal_hrabs
  2013   star_n_divide <-- hcomplex_divide
  2014 
  2015   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2016   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2017   star_of_diff <-- hypreal_of_real_diff
  2018   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2019   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2020   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2021   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2022   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2023   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2024   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2025   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2026   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2027   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2028   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2029   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2030   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2031   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2032   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2033   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2034   star_of_power <-- hypreal_of_real_power
  2035   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2036 
  2037 * Hyperreal: new method "transfer" that implements the transfer
  2038 principle of nonstandard analysis. With a subgoal that mentions
  2039 nonstandard types like "'a star", the command "apply transfer"
  2040 replaces it with an equivalent one that mentions only standard types.
  2041 To be successful, all free variables must have standard types; non-
  2042 standard variables must have explicit universal quantifiers.
  2043 
  2044 * Hyperreal: A theory of Taylor series.
  2045 
  2046 
  2047 *** HOLCF ***
  2048 
  2049 * Discontinued special version of 'constdefs' (which used to support
  2050 continuous functions) in favor of the general Pure one with full
  2051 type-inference.
  2052 
  2053 * New simplification procedure for solving continuity conditions; it
  2054 is much faster on terms with many nested lambda abstractions (cubic
  2055 instead of exponential time).
  2056 
  2057 * New syntax for domain package: selector names are now optional.
  2058 Parentheses should be omitted unless argument is lazy, for example:
  2059 
  2060   domain 'a stream = cons "'a" (lazy "'a stream")
  2061 
  2062 * New command 'fixrec' for defining recursive functions with pattern
  2063 matching; defining multiple functions with mutual recursion is also
  2064 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2065 sinr, or any data constructor defined by the domain package. The given
  2066 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2067 syntax and examples.
  2068 
  2069 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2070 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2071 but the proof obligation additionally includes an admissibility
  2072 requirement. The packages generate instances of class cpo or pcpo,
  2073 with continuity and strictness theorems for Rep and Abs.
  2074 
  2075 * HOLCF: Many theorems have been renamed according to a more standard naming
  2076 scheme (INCOMPATIBILITY):
  2077 
  2078   foo_inject:  "foo$x = foo$y ==> x = y"
  2079   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2080   foo_less:    "(foo$x << foo$y) = (x << y)"
  2081   foo_strict:  "foo$UU = UU"
  2082   foo_defined: "... ==> foo$x ~= UU"
  2083   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2084 
  2085 
  2086 *** ZF ***
  2087 
  2088 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2089 including the First Isomorphism Theorem (on quotienting by the kernel
  2090 of a homomorphism).
  2091 
  2092 * ZF/Simplifier: install second copy of type solver that actually
  2093 makes use of TC rules declared to Isar proof contexts (or locales);
  2094 the old version is still required for ML proof scripts.
  2095 
  2096 
  2097 *** Cube ***
  2098 
  2099 * Converted to Isar theory format; use locales instead of axiomatic
  2100 theories.
  2101 
  2102 
  2103 *** ML ***
  2104 
  2105 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2106 for ||>, ||>>, |>>,
  2107 
  2108 * Pure/library.ML no longer defines its own option datatype, but uses
  2109 that of the SML basis, which has constructors NONE and SOME instead of
  2110 None and Some, as well as exception Option.Option instead of OPTION.
  2111 The functions the, if_none, is_some, is_none have been adapted
  2112 accordingly, while Option.map replaces apsome.
  2113 
  2114 * Pure/library.ML: the exception LIST has been given up in favour of
  2115 the standard exceptions Empty and Subscript, as well as
  2116 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2117 superceded by the standard hd and tl functions etc.
  2118 
  2119 A number of basic list functions are no longer exported to the ML
  2120 toplevel, as they are variants of predefined functions.  The following
  2121 suggests how one can translate existing code:
  2122 
  2123     rev_append xs ys = List.revAppend (xs, ys)
  2124     nth_elem (i, xs) = List.nth (xs, i)
  2125     last_elem xs = List.last xs
  2126     flat xss = List.concat xss
  2127     seq fs = List.app fs
  2128     partition P xs = List.partition P xs
  2129     mapfilter f xs = List.mapPartial f xs
  2130 
  2131 * Pure/library.ML: several combinators for linear functional
  2132 transformations, notably reverse application and composition:
  2133 
  2134   x |> f                f #> g
  2135   (x, y) |-> f          f #-> g
  2136 
  2137 * Pure/library.ML: introduced/changed precedence of infix operators:
  2138 
  2139   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2140   infix 2 ?;
  2141   infix 3 o oo ooo oooo;
  2142   infix 4 ~~ upto downto;
  2143 
  2144 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2145 infix operators.
  2146 
  2147 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2148 fold_map support linear functional transformations and nesting.  For
  2149 example:
  2150 
  2151   fold f [x1, ..., xN] y =
  2152     y |> f x1 |> ... |> f xN
  2153 
  2154   (fold o fold) f [xs1, ..., xsN] y =
  2155     y |> fold f xs1 |> ... |> fold f xsN
  2156 
  2157   fold f [x1, ..., xN] =
  2158     f x1 #> ... #> f xN
  2159 
  2160   (fold o fold) f [xs1, ..., xsN] =
  2161     fold f xs1 #> ... #> fold f xsN
  2162 
  2163 * Pure/library.ML: the following selectors on type 'a option are
  2164 available:
  2165 
  2166   the:               'a option -> 'a  (*partial*)
  2167   these:             'a option -> 'a  where 'a = 'b list
  2168   the_default: 'a -> 'a option -> 'a
  2169   the_list:          'a option -> 'a list
  2170 
  2171 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2172 basic operations for association lists, following natural argument
  2173 order; moreover the explicit equality predicate passed here avoids
  2174 potentially expensive polymorphic runtime equality checks.
  2175 The old functions may be expressed as follows:
  2176 
  2177   assoc = uncurry (AList.lookup (op =))
  2178   assocs = these oo AList.lookup (op =)
  2179   overwrite = uncurry (AList.update (op =)) o swap
  2180 
  2181 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2182 
  2183   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2184   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2185 
  2186 replacing make_keylist and keyfilter (occassionally used)
  2187 Naive rewrites:
  2188 
  2189   make_keylist = AList.make
  2190   keyfilter = AList.find (op =)
  2191 
  2192 * eq_fst and eq_snd now take explicit equality parameter, thus
  2193   avoiding eqtypes. Naive rewrites:
  2194 
  2195     eq_fst = eq_fst (op =)
  2196     eq_snd = eq_snd (op =)
  2197 
  2198 * Removed deprecated apl and apr (rarely used).
  2199   Naive rewrites:
  2200 
  2201     apl (n, op) =>>= curry op n
  2202     apr (op, m) =>>= fn n => op (n, m)
  2203 
  2204 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2205 provides a reasonably efficient light-weight implementation of sets as
  2206 lists.
  2207 
  2208 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2209 few new operations; existing lookup and update are now curried to
  2210 follow natural argument order (for use with fold etc.);
  2211 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2212 
  2213 * Pure/General: output via the Isabelle channels of
  2214 writeln/warning/error etc. is now passed through Output.output, with a
  2215 hook for arbitrary transformations depending on the print_mode
  2216 (cf. Output.add_mode -- the first active mode that provides a output
  2217 function wins).  Already formatted output may be embedded into further
  2218 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2219 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2220 accommodate easy composition of diagnostic messages etc.  Programmers
  2221 rarely need to care about Output.output or Output.raw at all, with
  2222 some notable exceptions: Output.output is required when bypassing the
  2223 standard channels (writeln etc.), or in token translations to produce
  2224 properly formatted results; Output.raw is required when capturing
  2225 already output material that will eventually be presented to the user
  2226 a second time.  For the default print mode, both Output.output and
  2227 Output.raw have no effect.
  2228 
  2229 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2230 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2231 cumulative results are displayed at the end of a batch session.
  2232 
  2233 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2234 replaced by File.platform_path and File.shell_path (with appropriate
  2235 hooks).  This provides a clean interface for unusual systems where the
  2236 internal and external process view of file names are different.
  2237 
  2238 * Pure: more efficient orders for basic syntactic entities: added
  2239 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2240 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2241 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2242 orders now -- potential INCOMPATIBILITY for code that depends on a
  2243 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2244 Library.sort_strings on result).
  2245 
  2246 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2247 fold_types traverse types/terms from left to right, observing natural
  2248 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2249 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2250 
  2251 * Pure: name spaces have been refined, with significant changes of the
  2252 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2253 to extern(_table).  The plain name entry path is superceded by a
  2254 general 'naming' context, which also includes the 'policy' to produce
  2255 a fully qualified name and external accesses of a fully qualified
  2256 name; NameSpace.extend is superceded by context dependent
  2257 Sign.declare_name.  Several theory and proof context operations modify
  2258 the naming context.  Especially note Theory.restore_naming and
  2259 ProofContext.restore_naming to get back to a sane state; note that
  2260 Theory.add_path is no longer sufficient to recover from
  2261 Theory.absolute_path in particular.
  2262 
  2263 * Pure: new flags short_names (default false) and unique_names
  2264 (default true) for controlling output of qualified names.  If
  2265 short_names is set, names are printed unqualified.  If unique_names is
  2266 reset, the name prefix is reduced to the minimum required to achieve
  2267 the original result when interning again, even if there is an overlap
  2268 with earlier declarations.
  2269 
  2270 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2271 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2272 (useful for printing error messages).  INCOMPATIBILITY.
  2273 
  2274 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2275 Theory.theory are now identified, referring to the universal
  2276 Context.theory (see Pure/context.ML).  Actual signature and theory
  2277 content is managed as theory data.  The old code and interfaces were
  2278 spread over many files and structures; the new arrangement introduces
  2279 considerable INCOMPATIBILITY to gain more clarity:
  2280 
  2281   Context -- theory management operations (name, identity, inclusion,
  2282     parents, ancestors, merge, etc.), plus generic theory data;
  2283 
  2284   Sign -- logical signature and syntax operations (declaring consts,
  2285     types, etc.), plus certify/read for common entities;
  2286 
  2287   Theory -- logical theory operations (stating axioms, definitions,
  2288     oracles), plus a copy of logical signature operations (consts,
  2289     types, etc.); also a few basic management operations (Theory.copy,
  2290     Theory.merge, etc.)
  2291 
  2292 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2293 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2294 for convenience -- they merely return the theory.
  2295 
  2296 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2297 
  2298 * Pure: the Isar proof context type is already defined early in Pure
  2299 as Context.proof (note that ProofContext.context and Proof.context are
  2300 aliases, where the latter is the preferred name).  This enables other
  2301 Isabelle components to refer to that type even before Isar is present.
  2302 
  2303 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2304 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2305 any of these kinds.  For example, Sign.intern typeK is now
  2306 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2307 Theory.hide_types.  Also note that former
  2308 Theory.hide_classes/types/consts are now
  2309 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2310 internalize their arguments!  INCOMPATIBILITY.
  2311 
  2312 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2313 datatype thmref (with constructors Name and NameSelection) instead of
  2314 plain string -- INCOMPATIBILITY;
  2315 
  2316 * Pure: cases produced by proof methods specify options, where NONE
  2317 means to remove case bindings -- INCOMPATIBILITY in
  2318 (RAW_)METHOD_CASES.
  2319 
  2320 * Pure: the following operations retrieve axioms or theorems from a
  2321 theory node or theory hierarchy, respectively:
  2322 
  2323   Theory.axioms_of: theory -> (string * term) list
  2324   Theory.all_axioms_of: theory -> (string * term) list
  2325   PureThy.thms_of: theory -> (string * thm) list
  2326   PureThy.all_thms_of: theory -> (string * thm) list
  2327 
  2328 * Pure: print_tac now outputs the goal through the trace channel.
  2329 
  2330 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2331 Reference Toplevel.debug (default false) controls detailed printing
  2332 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2333 controls execution profiling -- set to 1 for time and 2 for space
  2334 (both increase the runtime).
  2335 
  2336 * Isar session: The initial use of ROOT.ML is now always timed,
  2337 i.e. the log will show the actual process times, in contrast to the
  2338 elapsed wall-clock time that the outer shell wrapper produces.
  2339 
  2340 * Simplifier: improved handling of bound variables (nameless
  2341 representation, avoid allocating new strings).  Simprocs that invoke
  2342 the Simplifier recursively should use Simplifier.inherit_bounds to
  2343 avoid local name clashes.  Failure to do so produces warnings
  2344 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2345 for further details.
  2346 
  2347 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2348 bindings for all theorems stored within a given theory; this may help
  2349 in porting non-Isar theories to Isar ones, while keeping ML proof
  2350 scripts for the time being.
  2351 
  2352 * ML operator HTML.with_charset specifies the charset begin used for
  2353 generated HTML files.  For example:
  2354 
  2355   HTML.with_charset "utf-8" use_thy "Hebrew";
  2356   HTML.with_charset "utf-8" use_thy "Chinese";
  2357 
  2358 
  2359 *** System ***
  2360 
  2361 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2362 isabelle, isatool etc.).
  2363 
  2364 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2365 isatool doc, isatool mkdir, display_drafts etc.).
  2366 
  2367 * isatool usedir: option -f allows specification of the ML file to be
  2368 used by Isabelle; default is ROOT.ML.
  2369 
  2370 * New isatool version outputs the version identifier of the Isabelle
  2371 distribution being used.
  2372 
  2373 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2374 (containing Boolean satisfiability problems) into Isabelle/HOL
  2375 theories.
  2376 
  2377 
  2378 
  2379 New in Isabelle2004 (April 2004)
  2380 --------------------------------
  2381 
  2382 *** General ***
  2383 
  2384 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2385   Replaces linorder.ML.
  2386 
  2387 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2388   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2389   (\<a>...\<z>), are now considered normal letters, and can therefore
  2390   be used anywhere where an ASCII letter (a...zA...Z) has until
  2391   now. COMPATIBILITY: This obviously changes the parsing of some
  2392   terms, especially where a symbol has been used as a binder, say
  2393   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2394   as an identifier.  Fix it by inserting a space around former
  2395   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2396   existing theory and ML files.
  2397 
  2398 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2399 
  2400 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2401   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2402   a normal (but invisible) letter. For multiple letter subscripts repeat
  2403   \<^isub> like this: x\<^isub>1\<^isub>2.
  2404 
  2405 * Pure: There are now sub-/superscripts that can span more than one
  2406   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2407   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2408   superscript. The new control characters are not identifier parts.
  2409 
  2410 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2411   content of "..." to the latex file instead of \isacntrl... . The "..."
  2412   may consist of any printable characters excluding the end bracket >.
  2413 
  2414 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2415   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2416   declare constants "final", which prevents their being given a definition
  2417   later.  It is useful for constants whose behaviour is fixed axiomatically
  2418   rather than definitionally, such as the meta-logic connectives.
  2419 
  2420 * Pure: 'instance' now handles general arities with general sorts
  2421   (i.e. intersections of classes),
  2422 
  2423 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2424   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2425   It can be changed to alter the colors/layout of generated pages.
  2426 
  2427 
  2428 *** Isar ***
  2429 
  2430 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2431   cut_tac, subgoal_tac and thin_tac:
  2432   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2433     locales are no longer forced to write Isar proof scripts.
  2434     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2435     emulations.
  2436   - INCOMPATIBILITY: names of variables to be instantiated may no
  2437     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2438     This is consistent with the instantiation attribute "where".
  2439 
  2440 * Attributes "where" and "of":
  2441   - Now take type variables of instantiated theorem into account when reading
  2442     the instantiation string.  This fixes a bug that caused instantiated
  2443     theorems to have too special types in some circumstances.
  2444   - "where" permits explicit instantiations of type variables.
  2445 
  2446 * Calculation commands "moreover" and "also" no longer interfere with
  2447   current facts ("this"), admitting arbitrary combinations with "then"
  2448   and derived forms.
  2449 
  2450 * Locales:
  2451   - Goal statements involving the context element "includes" no longer
  2452     generate theorems with internal delta predicates (those ending on
  2453     "_axioms") in the premise.
  2454     Resolve particular premise with <locale>.intro to obtain old form.
  2455   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2456     specification and "includes" elements in goal statement.
  2457   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2458     [intro?] and [elim?] (respectively) by default.
  2459   - Experimental command for instantiation of locales in proof contexts:
  2460         instantiate <label>[<attrs>]: <loc>
  2461     Instantiates locale <loc> and adds all its theorems to the current context
  2462     taking into account their attributes.  Label and attrs are optional
  2463     modifiers, like in theorem declarations.  If present, names of
  2464     instantiated theorems are qualified with <label>, and the attributes
  2465     <attrs> are applied after any attributes these theorems might have already.
  2466       If the locale has assumptions, a chained fact of the form
  2467     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2468     are derived.  The command does not support old-style locales declared
  2469     with "locale (open)".
  2470       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2471 
  2472 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2473   (Isar) contexts.
  2474 
  2475 
  2476 *** HOL ***
  2477 
  2478 * Proof import: new image HOL4 contains the imported library from
  2479   the HOL4 system with about 2500 theorems. It is imported by
  2480   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2481   can be used like any other Isabelle image.  See
  2482   HOL/Import/HOL/README for more information.
  2483 
  2484 * Simplifier:
  2485   - Much improved handling of linear and partial orders.
  2486     Reasoners for linear and partial orders are set up for type classes
  2487     "linorder" and "order" respectively, and are added to the default simpset
  2488     as solvers.  This means that the simplifier can build transitivity chains
  2489     to solve goals from the assumptions.
  2490   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2491     of blast or auto after simplification become unnecessary because the goal
  2492     is solved by simplification already.
  2493 
  2494 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2495     all proved in axiomatic type classes for semirings, rings and fields.
  2496 
  2497 * Numerics:
  2498   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2499     now formalized using the Ring_and_Field theory mentioned above.
  2500   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2501     than before, because now they are set up once in a generic manner.
  2502   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2503     Look for the general versions in Ring_and_Field (and Power if they concern
  2504     exponentiation).
  2505 
  2506 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2507 
  2508 * Records:
  2509   - Record types are now by default printed with their type abbreviation
  2510     instead of the list of all field types. This can be configured via
  2511     the reference "print_record_type_abbr".
  2512   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2513     (not enabled by default).
  2514   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2515     EX x. x = sel r to True (not enabled by default).
  2516   - Tactic "record_split_simp_tac" to split and simplify records added.
  2517 
  2518 * 'specification' command added, allowing for definition by
  2519   specification.  There is also an 'ax_specification' command that
  2520   introduces the new constants axiomatically.
  2521 
  2522 * arith(_tac) is now able to generate counterexamples for reals as well.
  2523 
  2524 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2525 
  2526 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2527   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2528 
  2529 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2530   matrix theory to linear programming.
  2531 
  2532 * Unions and Intersections:
  2533   The latex output syntax of UN and INT has been changed
  2534   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2535   i.e. the index formulae has become a subscript.
  2536   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2537 
  2538 * Unions and Intersections over Intervals:
  2539   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2540   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2541   like in normal math, and corresponding versions for < and for intersection.
  2542 
  2543 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2544   lexicographic dictonary ordering has been added as "lexord".
  2545 
  2546 * ML: the legacy theory structures Int and List have been removed. They had
  2547   conflicted with ML Basis Library structures having the same names.
  2548 
  2549 * 'refute' command added to search for (finite) countermodels.  Only works
  2550   for a fragment of HOL.  The installation of an external SAT solver is
  2551   highly recommended.  See "HOL/Refute.thy" for details.
  2552 
  2553 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2554   formulae under an assignment of free variables to random values.
  2555   In contrast to 'refute', it can deal with inductive datatypes,
  2556   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2557   for examples.
  2558 
  2559 
  2560 *** HOLCF ***
  2561 
  2562 * Streams now come with concatenation and are part of the HOLCF image
  2563 
  2564 
  2565 
  2566 New in Isabelle2003 (May 2003)
  2567 ------------------------------
  2568 
  2569 *** General ***
  2570 
  2571 * Provers/simplifier:
  2572 
  2573   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2574     Assumptions are now subject to complete mutual simplification,
  2575     not just from left to right. The simplifier now preserves
  2576     the order of assumptions.
  2577 
  2578     Potential INCOMPATIBILITY:
  2579 
  2580     -- simp sometimes diverges where the old version did
  2581        not, e.g. invoking simp on the goal
  2582 
  2583         [| P (f x); y = x; f x = f y |] ==> Q
  2584 
  2585        now gives rise to the infinite reduction sequence
  2586 
  2587         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2588 
  2589        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2590        kind of problem.
  2591 
  2592     -- Tactics combining classical reasoner and simplification (such as auto)
  2593        are also affected by this change, because many of them rely on
  2594        simp. They may sometimes diverge as well or yield a different numbers
  2595        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2596        in case of problems. Sometimes subsequent calls to the classical
  2597        reasoner will fail because a preceeding call to the simplifier too
  2598        eagerly simplified the goal, e.g. deleted redundant premises.
  2599 
  2600   - The simplifier trace now shows the names of the applied rewrite rules
  2601 
  2602   - You can limit the number of recursive invocations of the simplifier
  2603     during conditional rewriting (where the simplifie tries to solve the
  2604     conditions before applying the rewrite rule):
  2605     ML "simp_depth_limit := n"
  2606     where n is an integer. Thus you can force termination where previously
  2607     the simplifier would diverge.
  2608 
  2609   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2610 
  2611   - No longer aborts on failed congruence proof.  Instead, the
  2612     congruence is ignored.
  2613 
  2614 * Pure: New generic framework for extracting programs from constructive
  2615   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2616   as HOL/Extraction for some case studies.
  2617 
  2618 * Pure: The main goal of the proof state is no longer shown by default, only
  2619 the subgoals. This behaviour is controlled by a new flag.
  2620    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2621 (ML: Proof.show_main_goal).
  2622 
  2623 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2624 rules whose conclusion matches subgoal 1:
  2625       PG menu: Isabelle/Isar -> Show me -> matching rules
  2626 The rules are ordered by how closely they match the subgoal.
  2627 In particular, rules that solve a subgoal outright are displayed first
  2628 (or rather last, the way they are printed).
  2629 (ML: ProofGeneral.print_intros())
  2630 
  2631 * Pure: New flag trace_unify_fail causes unification to print
  2632 diagnostic information (PG: in trace buffer) when it fails. This is
  2633 useful for figuring out why single step proofs like rule, erule or
  2634 assumption failed.
  2635 
  2636 * Pure: Locale specifications now produce predicate definitions
  2637 according to the body of text (covering assumptions modulo local
  2638 definitions); predicate "loc_axioms" covers newly introduced text,
  2639 while "loc" is cumulative wrt. all included locale expressions; the
  2640 latter view is presented only on export into the global theory
  2641 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2642 on the old view without predicates;
  2643 
  2644 * Pure: predefined locales "var" and "struct" are useful for sharing
  2645 parameters (as in CASL, for example); just specify something like
  2646 ``var x + var y + struct M'' as import;
  2647 
  2648 * Pure: improved thms_containing: proper indexing of facts instead of
  2649 raw theorems; check validity of results wrt. current name space;
  2650 include local facts of proof configuration (also covers active
  2651 locales), cover fixed variables in index; may use "_" in term
  2652 specification; an optional limit for the number of printed facts may
  2653 be given (the default is 40);
  2654 
  2655 * Pure: disallow duplicate fact bindings within new-style theory files
  2656 (batch-mode only);
  2657 
  2658 * Provers: improved induct method: assumptions introduced by case
  2659 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2660 the goal statement); "foo" still refers to all facts collectively;
  2661 
  2662 * Provers: the function blast.overloaded has been removed: all constants
  2663 are regarded as potentially overloaded, which improves robustness in exchange
  2664 for slight decrease in efficiency;
  2665 
  2666 * Provers/linorder: New generic prover for transitivity reasoning over
  2667 linear orders.  Note: this prover is not efficient!
  2668 
  2669 * Isar: preview of problems to finish 'show' now produce an error
  2670 rather than just a warning (in interactive mode);
  2671 
  2672 
  2673 *** HOL ***
  2674 
  2675 * arith(_tac)
  2676 
  2677  - Produces a counter example if it cannot prove a goal.
  2678    Note that the counter example may be spurious if the goal is not a formula
  2679    of quantifier-free linear arithmetic.
  2680    In ProofGeneral the counter example appears in the trace buffer.
  2681 
  2682  - Knows about div k and mod k where k is a numeral of type nat or int.
  2683 
  2684  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2685    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2686    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2687 
  2688 * simp's arithmetic capabilities have been enhanced a bit: it now
  2689 takes ~= in premises into account (by performing a case split);
  2690 
  2691 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2692 are distributed over a sum of terms;
  2693 
  2694 * New tactic "trans_tac" and method "trans" instantiate
  2695 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2696 "<=", "<" and "=").
  2697 
  2698 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2699 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2700 
  2701 * 'typedef' command has new option "open" to suppress the set
  2702 definition;
  2703 
  2704 * functions Min and Max on finite sets have been introduced (theory
  2705 Finite_Set);
  2706 
  2707 * attribute [symmetric] now works for relations as well; it turns
  2708 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2709 
  2710 * induct over a !!-quantified statement (say !!x1..xn):
  2711   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2712 
  2713 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2714 %x. None. Warning: empty_def now refers to the previously hidden definition
  2715 of the empty set.
  2716 
  2717 * Algebra: formalization of classical algebra.  Intended as base for
  2718 any algebraic development in Isabelle.  Currently covers group theory
  2719 (up to Sylow's theorem) and ring theory (Universal Property of
  2720 Univariate Polynomials).  Contributions welcome;
  2721 
  2722 * GroupTheory: deleted, since its material has been moved to Algebra;
  2723 
  2724 * Complex: new directory of the complex numbers with numeric constants,
  2725 nonstandard complex numbers, and some complex analysis, standard and
  2726 nonstandard (Jacques Fleuriot);
  2727 
  2728 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2729 
  2730 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2731 Fleuriot);
  2732 
  2733 * Real/HahnBanach: updated and adapted to locales;
  2734 
  2735 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2736 Gray and Kramer);
  2737 
  2738 * UNITY: added the Meier-Sanders theory of progress sets;
  2739 
  2740 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2741 as abstract algorithms, instantiated to the JVM;
  2742 
  2743 * Bali: Java source language formalization. Type system, operational
  2744 semantics, axiomatic semantics. Supported language features:
  2745 classes, interfaces, objects,virtual methods, static methods,
  2746 static/instance fields, arrays, access modifiers, definite
  2747 assignment, exceptions.
  2748 
  2749 
  2750 *** ZF ***
  2751 
  2752 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2753 universe, etc.);
  2754 
  2755 * Main ZF: virtually all theories converted to new-style format;
  2756 
  2757 
  2758 *** ML ***
  2759 
  2760 * Pure: Tactic.prove provides sane interface for internal proofs;
  2761 omits the infamous "standard" operation, so this is more appropriate
  2762 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2763 
  2764 * Pure: improved error reporting of simprocs;
  2765 
  2766 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2767 up simprocs;
  2768 
  2769 
  2770 *** Document preparation ***
  2771 
  2772 * uses \par instead of \\ for line breaks in theory text. This may
  2773 shift some page breaks in large documents. To get the old behaviour
  2774 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2775 
  2776 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2777 other packages
  2778 
  2779 * \<euro> now needs package babel/greek instead of marvosym (which
  2780 broke \Rightarrow)
  2781 
  2782 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2783 textcomp package)
  2784 
  2785 
  2786 
  2787 New in Isabelle2002 (March 2002)
  2788 --------------------------------
  2789 
  2790 *** Document preparation ***
  2791 
  2792 * greatly simplified document preparation setup, including more
  2793 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2794 instructive isatool mkdir; users should basically be able to get
  2795 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2796 users may run a separate document processing stage manually like this:
  2797 "isatool usedir -D output HOL Test && isatool document Test/output";
  2798 
  2799 * theory dependency graph may now be incorporated into documents;
  2800 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2801 with \includegraphics of LaTeX;
  2802 
  2803 * proper spacing of consecutive markup elements, especially text
  2804 blocks after section headings;
  2805 
  2806 * support bold style (for single symbols only), input syntax is like
  2807 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2808 
  2809 * \<bullet> is now output as bold \cdot by default, which looks much
  2810 better in printed text;
  2811 
  2812 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2813 note that these symbols are currently unavailable in Proof General /
  2814 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2815 
  2816 * isatool latex no longer depends on changed TEXINPUTS, instead
  2817 isatool document copies the Isabelle style files to the target
  2818 location;
  2819 
  2820 
  2821 *** Isar ***
  2822 
  2823 * Pure/Provers: improved proof by cases and induction;
  2824   - 'case' command admits impromptu naming of parameters (such as
  2825     "case (Suc n)");
  2826   - 'induct' method divinates rule instantiation from the inductive
  2827     claim; no longer requires excessive ?P bindings for proper
  2828     instantiation of cases;
  2829   - 'induct' method properly enumerates all possibilities of set/type
  2830     rules; as a consequence facts may be also passed through *type*
  2831     rules without further ado;
  2832   - 'induct' method now derives symbolic cases from the *rulified*
  2833     rule (before it used to rulify cases stemming from the internal
  2834     atomized version); this means that the context of a non-atomic
  2835     statement becomes is included in the hypothesis, avoiding the
  2836     slightly cumbersome show "PROP ?case" form;
  2837   - 'induct' may now use elim-style induction rules without chaining
  2838     facts, using ``missing'' premises from the goal state; this allows
  2839     rules stemming from inductive sets to be applied in unstructured
  2840     scripts, while still benefitting from proper handling of non-atomic
  2841     statements; NB: major inductive premises need to be put first, all
  2842     the rest of the goal is passed through the induction;
  2843   - 'induct' proper support for mutual induction involving non-atomic
  2844     rule statements (uses the new concept of simultaneous goals, see
  2845     below);
  2846   - append all possible rule selections, but only use the first
  2847     success (no backtracking);
  2848   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2849   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2850   - added 'print_induct_rules' (covered by help item in recent Proof
  2851     General versions);
  2852   - moved induct/cases attributes to Pure, methods to Provers;
  2853   - generic method setup instantiated for FOL and HOL;
  2854 
  2855 * Pure: support multiple simultaneous goal statements, for example
  2856 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2857 meta-level mechanism, this acts as if several individual goals had
  2858 been stated separately; in particular common proof methods need to be
  2859 repeated in order to cover all claims; note that a single elimination
  2860 step is *not* sufficient to establish the two conjunctions, so this
  2861 fails:
  2862 
  2863   assume "A & B" then have A and B ..   (*".." fails*)
  2864 
  2865 better use "obtain" in situations as above; alternative refer to
  2866 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2867 
  2868 * Pure: proper integration with ``locales''; unlike the original
  2869 version by Florian Kammller, Isar locales package high-level proof
  2870 contexts rather than raw logical ones (e.g. we admit to include
  2871 attributes everywhere); operations on locales include merge and
  2872 rename; support for implicit arguments (``structures''); simultaneous
  2873 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2874 some examples;
  2875 
  2876 * Pure: the following commands have been ``localized'', supporting a
  2877 target locale specification "(in name)": 'lemma', 'theorem',
  2878 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2879 stored both within the locale and at the theory level (exported and
  2880 qualified by the locale name);
  2881 
  2882 * Pure: theory goals may now be specified in ``long'' form, with
  2883 ad-hoc contexts consisting of arbitrary locale elements. for example
  2884 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2885 definitions may be given, too); the result is a meta-level rule with
  2886 the context elements being discharged in the obvious way;
  2887 
  2888 * Pure: new proof command 'using' allows to augment currently used
  2889 facts after a goal statement ('using' is syntactically analogous to
  2890 'apply', but acts on the goal's facts only); this allows chained facts
  2891 to be separated into parts given before and after a claim, as in
  2892 ``from a and b have C using d and e <proof>'';
  2893 
  2894 * Pure: renamed "antecedent" case to "rule_context";
  2895 
  2896 * Pure: new 'judgment' command records explicit information about the
  2897 object-logic embedding (used by several tools internally); no longer
  2898 use hard-wired "Trueprop";
  2899 
  2900 * Pure: added 'corollary' command;
  2901 
  2902 * Pure: fixed 'token_translation' command;
  2903 
  2904 * Pure: removed obsolete 'exported' attribute;
  2905 
  2906 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2907 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2908 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2909 
  2910 * Pure: method 'atomize' presents local goal premises as object-level
  2911 statements (atomic meta-level propositions); setup controlled via
  2912 rewrite rules declarations of 'atomize' attribute; example
  2913 application: 'induct' method with proper rule statements in improper
  2914 proof *scripts*;
  2915 
  2916 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2917 now consider the syntactic context of assumptions, giving a better
  2918 chance to get type-inference of the arguments right (this is
  2919 especially important for locales);
  2920 
  2921 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2922 mode;
  2923 
  2924 * Pure/obtain: the formal conclusion "thesis", being marked as
  2925 ``internal'', may no longer be reference directly in the text;
  2926 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2927 situations;
  2928 
  2929 * Pure: generic 'sym' attribute which declares a rule both as pure
  2930 'elim?' and for the 'symmetric' operation;
  2931 
  2932 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2933 text; the fixed correlation with particular command syntax has been
  2934 discontinued;
  2935 
  2936 * Pure: new method 'rules' is particularly well-suited for proof
  2937 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2938 but often produces more compact proof terms with less detours;
  2939 
  2940 * Pure/Provers/classical: simplified integration with pure rule
  2941 attributes and methods; the classical "intro?/elim?/dest?"
  2942 declarations coincide with the pure ones; the "rule" method no longer
  2943 includes classically swapped intros; "intro" and "elim" methods no
  2944 longer pick rules from the context; also got rid of ML declarations
  2945 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2946 INCOMPATIBILITY;
  2947 
  2948 * Provers/classical: attribute 'swapped' produces classical inversions
  2949 of introduction rules;
  2950 
  2951 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2952 rules instead of full simplifier context; 'iff' attribute handles
  2953 conditional rules;
  2954 
  2955 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2956 
  2957 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2958 "(permissive)" option to recover old behavior;
  2959 
  2960 * HOL: 'inductive' no longer features separate (collective) attributes
  2961 for 'intros' (was found too confusing);
  2962 
  2963 * HOL: properly declared induction rules less_induct and
  2964 wf_induct_rule;
  2965 
  2966 
  2967 *** HOL ***
  2968 
  2969 * HOL: moved over to sane numeral syntax; the new policy is as
  2970 follows:
  2971 
  2972   - 0 and 1 are polymorphic constants, which are defined on any
  2973   numeric type (nat, int, real etc.);
  2974 
  2975   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2976   binary representation internally;
  2977 
  2978   - type nat has special constructor Suc, and generally prefers Suc 0
  2979   over 1::nat and Suc (Suc 0) over 2::nat;
  2980 
  2981 This change may cause significant problems of INCOMPATIBILITY; here
  2982 are some hints on converting existing sources:
  2983 
  2984   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2985   entities, so expressions involving "-" (unary or binary minus) need
  2986   to be spaced properly;
  2987 
  2988   - existing occurrences of "1" may need to be constraint "1::nat" or
  2989   even replaced by Suc 0; similar for old "2";
  2990 
  2991   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2992 
  2993   - remove all special provisions on numerals in proofs;
  2994 
  2995 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2996 representation (depends on bin_arith_simps in the default context);
  2997 
  2998 * HOL: symbolic syntax for x^2 (numeral 2);
  2999 
  3000 * HOL: the class of all HOL types is now called "type" rather than
  3001 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3002 in axclass/classes, instance/arities, and (usually rare) occurrences
  3003 in typings (of consts etc.); internally the class is called
  3004 "HOL.type", ML programs should refer to HOLogic.typeS;
  3005 
  3006 * HOL/record package improvements:
  3007   - new derived operations "fields" to build a partial record section,
  3008     "extend" to promote a fixed record to a record scheme, and
  3009     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3010     declared as simp by default;
  3011   - shared operations ("more", "fields", etc.) now need to be always
  3012     qualified) --- potential INCOMPATIBILITY;
  3013   - removed "make_scheme" operations (use "make" with "extend") --
  3014     INCOMPATIBILITY;
  3015   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3016   - provides cases/induct rules for use with corresponding Isar
  3017     methods (for concrete records, record schemes, concrete more
  3018     parts, and schematic more parts -- in that order);
  3019   - internal definitions directly based on a light-weight abstract
  3020     theory of product types over typedef rather than datatype;
  3021 
  3022 * HOL: generic code generator for generating executable ML code from
  3023 specifications; specific support for HOL constructs such as inductive
  3024 datatypes and sets, as well as recursive functions; can be invoked
  3025 via 'generate_code' theory section;
  3026 
  3027 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3028 
  3029 * HOL: consolidated and renamed several theories.  In particular:
  3030         Ord.thy has been absorbed into HOL.thy
  3031         String.thy has been absorbed into List.thy
  3032 
  3033 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3034 (beware of argument permutation!);
  3035 
  3036 * HOL: linorder_less_split superseded by linorder_cases;
  3037 
  3038 * HOL/List: "nodups" renamed to "distinct";
  3039 
  3040 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3041 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3042   - Ex_def has changed, now need to use some_eq_ex
  3043 
  3044 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3045 in this (rare) case use:
  3046 
  3047   delSWrapper "split_all_tac"
  3048   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3049 
  3050 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3051 MAY FAIL;
  3052 
  3053 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3054 Isabelle's type classes, ^ on functions and relations has too general
  3055 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3056 necessary to attach explicit type constraints;
  3057 
  3058 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3059 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3060 renamed accordingly (eg "compI" -> "rel_compI").
  3061 
  3062 * HOL: syntax translations now work properly with numerals and records
  3063 expressions;
  3064 
  3065 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3066 of "lam" -- INCOMPATIBILITY;
  3067 
  3068 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3069 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3070 renamed "Product_Type.unit";
  3071 
  3072 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3073 
  3074 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3075 the "cases" method);
  3076 
  3077 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3078 Florian Kammller);
  3079 
  3080 * HOL/IMP: updated and converted to new-style theory format; several
  3081 parts turned into readable document, with proper Isar proof texts and
  3082 some explanations (by Gerwin Klein);
  3083 
  3084 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3085 
  3086 * HOL-Hyperreal is now a logic image;
  3087 
  3088 
  3089 *** HOLCF ***
  3090 
  3091 * Isar: consts/constdefs supports mixfix syntax for continuous
  3092 operations;
  3093 
  3094 * Isar: domain package adapted to new-style theory format, e.g. see
  3095 HOLCF/ex/Dnat.thy;
  3096 
  3097 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3098 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3099 lift.induct_tac, always use UU instead of Undef;
  3100 
  3101 * HOLCF/IMP: updated and converted to new-style theory;
  3102 
  3103 
  3104 *** ZF ***
  3105 
  3106 * Isar: proper integration of logic-specific tools and packages,
  3107 including theory commands '(co)inductive', '(co)datatype',
  3108 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3109 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3110 
  3111 * theory Main no longer includes AC; for the Axiom of Choice, base
  3112 your theory on Main_ZFC;
  3113 
  3114 * the integer library now covers quotients and remainders, with many
  3115 laws relating division to addition, multiplication, etc.;
  3116 
  3117 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3118 typeless version of the formalism;
  3119 
  3120 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3121 format;
  3122 
  3123 * ZF/Induct: new directory for examples of inductive definitions,
  3124 including theory Multiset for multiset orderings; converted to
  3125 new-style theory format;
  3126 
  3127 * ZF: many new theorems about lists, ordinals, etc.;
  3128 
  3129 
  3130 *** General ***
  3131 
  3132 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3133 variable proof controls level of detail: 0 = no proofs (only oracle
  3134 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3135 also ref manual for further ML interfaces;
  3136 
  3137 * Pure/axclass: removed obsolete ML interface
  3138 goal_subclass/goal_arity;
  3139 
  3140 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3141 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3142 separate tokens, so expressions involving minus need to be spaced
  3143 properly;
  3144 
  3145 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3146 rather than "infixl" or "infixr";
  3147 
  3148 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3149 sort constraint specifications in type inference; e.g. "x::_::foo"
  3150 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3151 type variable);
  3152 
  3153 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3154 control output of nested => (types); the default behavior is
  3155 "type_brackets";
  3156 
  3157 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3158 tokens into AST constants;
  3159 
  3160 * Pure/syntax: prefer later declarations of translations and print
  3161 translation functions; potential INCOMPATIBILITY: need to reverse
  3162 multiple declarations for same syntax element constant;
  3163 
  3164 * Pure/show_hyps reset by default (in accordance to existing Isar
  3165 practice);
  3166 
  3167 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3168 addSafter;
  3169 
  3170 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3171 as well;
  3172 
  3173 * system: tested support for MacOS X; should be able to get Isabelle +
  3174 Proof General to work in a plain Terminal after installing Poly/ML
  3175 (e.g. from the Isabelle distribution area) and GNU bash alone
  3176 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3177 support requires further installations, e.g. from
  3178 http://fink.sourceforge.net/);
  3179 
  3180 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3181 
  3182 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3183 of 40 MB), cf. ML_OPTIONS;
  3184 
  3185 * system: Proof General keywords specification is now part of the
  3186 Isabelle distribution (see etc/isar-keywords.el);
  3187 
  3188 * system: support for persistent Proof General sessions (refrain from
  3189 outdating all loaded theories on startup); user may create writable
  3190 logic images like this: ``isabelle -q HOL Test'';
  3191 
  3192 * system: smart selection of Isabelle process versus Isabelle
  3193 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3194 run both "isabelle" and "Isabelle" even if file names are badly
  3195 damaged (executable inspects the case of the first letter of its own
  3196 name); added separate "isabelle-process" and "isabelle-interface";
  3197 
  3198 * system: refrain from any attempt at filtering input streams; no
  3199 longer support ``8bit'' encoding of old isabelle font, instead proper
  3200 iso-latin characters may now be used; the related isatools
  3201 "symbolinput" and "nonascii" have disappeared as well;
  3202 
  3203 * system: removed old "xterm" interface (the print modes "xterm" and
  3204 "xterm_color" are still available for direct use in a suitable
  3205 terminal);
  3206 
  3207 
  3208 
  3209 New in Isabelle99-2 (February 2001)
  3210 -----------------------------------
  3211 
  3212 *** Overview of INCOMPATIBILITIES ***
  3213 
  3214 * HOL: please note that theories in the Library and elsewhere often use the
  3215 new-style (Isar) format; to refer to their theorems in an ML script you must
  3216 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3217 
  3218 * HOL: inductive package no longer splits induction rule aggressively,
  3219 but only as far as specified by the introductions given; the old
  3220 format may be recovered via ML function complete_split_rule or attribute
  3221 'split_rule (complete)';
  3222 
  3223 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3224 gfp_Tarski to gfp_unfold;
  3225 
  3226 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3227 
  3228 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3229 relation); infix "^^" has been renamed "``"; infix "``" has been
  3230 renamed "`"; "univalent" has been renamed "single_valued";
  3231 
  3232 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3233 operation;
  3234 
  3235 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3236 
  3237 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3238 
  3239 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3240 consequence, it is no longer monotonic wrt. the local goal context
  3241 (which is now passed through the inductive cases);
  3242 
  3243 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3244 \<gg> to \<ggreater>;
  3245 
  3246 
  3247 *** Document preparation ***
  3248 
  3249 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3250 available: are "it" for near math-mode best-style output, "sl" for
  3251 slanted text style, and "tt" for plain type-writer; if no
  3252 \isabellestyle command is given, output is according to slanted
  3253 type-writer);
  3254 
  3255 * support sub/super scripts (for single symbols only), input syntax is
  3256 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3257 
  3258 * some more standard symbols; see Appendix A of the system manual for
  3259 the complete list of symbols defined in isabellesym.sty;
  3260 
  3261 * improved isabelle style files; more abstract symbol implementation
  3262 (should now use \isamath{...} and \isatext{...} in custom symbol
  3263 definitions);
  3264 
  3265 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3266 state; Note that presentation of goal states does not conform to
  3267 actual human-readable proof documents.  Please do not include goal
  3268 states into document output unless you really know what you are doing!
  3269 
  3270 * proper indentation of antiquoted output with proportional LaTeX
  3271 fonts;
  3272 
  3273 * no_document ML operator temporarily disables LaTeX document
  3274 generation;
  3275 
  3276 * isatool unsymbolize tunes sources for plain ASCII communication;
  3277 
  3278 
  3279 *** Isar ***
  3280 
  3281 * Pure: Isar now suffers initial goal statements to contain unbound
  3282 schematic variables (this does not conform to actual readable proof
  3283 documents, due to unpredictable outcome and non-compositional proof
  3284 checking); users who know what they are doing may use schematic goals
  3285 for Prolog-style synthesis of proven results;
  3286 
  3287 * Pure: assumption method (an implicit finishing) now handles actual
  3288 rules as well;
  3289 
  3290 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3291 initial goal, declare "that" only as Pure intro (only for single
  3292 steps); the "that" rule assumption may now be involved in implicit
  3293 finishing, thus ".." becomes a feasible for trivial obtains;
  3294 
  3295 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3296 instance proofs may be performed by "..";
  3297 
  3298 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3299 statements as well;
  3300 
  3301 * Pure: more robust selection of calculational rules;
  3302 
  3303 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3304 rule (as well as the assumption rule);
  3305 
  3306 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3307 lemmas, using the graph browser tool;
  3308 
  3309 * Pure: predict failure of "show" in interactive mode;
  3310 
  3311 * Pure: 'thms_containing' now takes actual terms as arguments;
  3312 
  3313 * HOL: improved method 'induct' --- now handles non-atomic goals
  3314 (potential INCOMPATIBILITY); tuned error handling;
  3315 
  3316 * HOL: cases and induct rules now provide explicit hints about the
  3317 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3318 any remaining facts are inserted into the goal verbatim;
  3319 
  3320 * HOL: local contexts (aka cases) may now contain term bindings as
  3321 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3322 the result to be shown in each case;
  3323 
  3324 * HOL: added 'recdef_tc' command;
  3325 
  3326 * isatool convert assists in eliminating legacy ML scripts;
  3327 
  3328 
  3329 *** HOL ***
  3330 
  3331 * HOL/Library: a collection of generic theories to be used together
  3332 with main HOL; the theory loader path already includes this directory
  3333 by default; the following existing theories have been moved here:
  3334 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3335 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3336 
  3337 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3338 modelling and verification task performed in Isabelle/HOL +
  3339 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3340 
  3341 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3342 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3343 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3344 'domain', this makes the theory consistent with mathematical
  3345 literature;
  3346 
  3347 * HOL basics: added overloaded operations "inverse" and "divide"
  3348 (infix "/"), syntax for generic "abs" operation, generic summation
  3349 operator \<Sum>;
  3350 
  3351 * HOL/typedef: simplified package, provide more useful rules (see also
  3352 HOL/subset.thy);
  3353 
  3354 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3355 now expressed as a proper nested rule (old-style tactic scripts may
  3356 require atomize_strip_tac to cope with non-atomic premises);
  3357 
  3358 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3359 to "split_conv" (old name still available for compatibility);
  3360 
  3361 * HOL: improved concrete syntax for strings (e.g. allows translation
  3362 rules with string literals);
  3363 
  3364 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3365  and Fleuriot's mechanization of analysis, including the transcendental
  3366  functions for the reals;
  3367 
  3368 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3369 
  3370 
  3371 *** CTT ***
  3372 
  3373 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3374 "lam" is displayed as TWO lambda-symbols
  3375 
  3376 * CTT: theory Main now available, containing everything (that is, Bool
  3377 and Arith);
  3378 
  3379 
  3380 *** General ***
  3381 
  3382 * Pure: the Simplifier has been implemented properly as a derived rule
  3383 outside of the actual kernel (at last!); the overall performance
  3384 penalty in practical applications is about 50%, while reliability of
  3385 the Isabelle inference kernel has been greatly improved;
  3386 
  3387 * print modes "brackets" and "no_brackets" control output of nested =>
  3388 (types) and ==> (props); the default behaviour is "brackets";
  3389 
  3390 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3391 as assumptions as well;
  3392 
  3393 * system: support Poly/ML 4.0;
  3394 
  3395 * system: isatool install handles KDE version 1 or 2;
  3396 
  3397 
  3398 
  3399 New in Isabelle99-1 (October 2000)
  3400 ----------------------------------
  3401 
  3402 *** Overview of INCOMPATIBILITIES ***
  3403 
  3404 * HOL: simplification of natural numbers is much changed; to partly
  3405 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3406 issue the following ML commands:
  3407 
  3408   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3409   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3410 
  3411 * HOL: simplification no longer dives into case-expressions; this is
  3412 controlled by "t.weak_case_cong" for each datatype t;
  3413 
  3414 * HOL: nat_less_induct renamed to less_induct;
  3415 
  3416 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3417 fixsome to patch .thy and .ML sources automatically;
  3418 
  3419   select_equality  -> some_equality
  3420   select_eq_Ex     -> some_eq_ex
  3421   selectI2EX       -> someI2_ex
  3422   selectI2         -> someI2
  3423   selectI          -> someI
  3424   select1_equality -> some1_equality
  3425   Eps_sym_eq       -> some_sym_eq_trivial
  3426   Eps_eq           -> some_eq_trivial
  3427 
  3428 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3429 
  3430 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3431 instead);
  3432 
  3433 * HOL: the recursion equations generated by 'recdef' are now called
  3434 f.simps instead of f.rules;
  3435 
  3436 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3437 
  3438 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3439 sometimes be needed;
  3440 
  3441 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3442 
  3443 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3444 
  3445 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3446 product is now "<*>" instead of "Times"; the lexicographic product is
  3447 now "<*lex*>" instead of "**";
  3448 
  3449 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3450 of main HOL, but was unused); better use HOL's datatype package;
  3451 
  3452 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3453 the old syntax may be recovered as follows:
  3454 
  3455   syntax (symbols)
  3456     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3457       (infixl "\\<oplus>" 100)
  3458 
  3459 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3460 
  3461 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3462 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3463 internally;
  3464 
  3465 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3466 changed from A/r to A//r;
  3467 
  3468 * ZF: new treatment of arithmetic (nat & int) may break some old
  3469 proofs;
  3470 
  3471 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3472 rulify -> rule_format, elimify -> elim_format, ...);
  3473 
  3474 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3475 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3476 should have to change intro!! to intro? only); replaced "delrule" by
  3477 "rule del";
  3478 
  3479 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3480 
  3481 * Provers: strengthened force_tac by using new first_best_tac;
  3482 
  3483 * LaTeX document preparation: several changes of isabelle.sty (see
  3484 lib/texinputs);
  3485 
  3486 
  3487 *** Document preparation ***
  3488 
  3489 * formal comments (text blocks etc.) in new-style theories may now
  3490 contain antiquotations of thm/prop/term/typ/text to be presented
  3491 according to latex print mode; concrete syntax is like this:
  3492 @{term[show_types] "f(x) = a + x"};
  3493 
  3494 * isatool mkdir provides easy setup of Isabelle session directories,
  3495 including proper document sources;
  3496 
  3497 * generated LaTeX sources are now deleted after successful run
  3498 (isatool document -c); may retain a copy somewhere else via -D option
  3499 of isatool usedir;
  3500 
  3501 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3502 style files, achieving self-contained LaTeX sources and simplifying
  3503 LaTeX debugging;
  3504 
  3505 * old-style theories now produce (crude) LaTeX output as well;
  3506 
  3507 * browser info session directories are now self-contained (may be put
  3508 on WWW server seperately); improved graphs of nested sessions; removed
  3509 graph for 'all sessions';
  3510 
  3511 * several improvements in isabelle style files; \isabellestyle{it}
  3512 produces fake math mode output; \isamarkupheader is now \section by
  3513 default; see lib/texinputs/isabelle.sty etc.;
  3514 
  3515 
  3516 *** Isar ***
  3517 
  3518 * Isar/Pure: local results and corresponding term bindings are now
  3519 subject to Hindley-Milner polymorphism (similar to ML); this
  3520 accommodates incremental type-inference very nicely;
  3521 
  3522 * Isar/Pure: new derived language element 'obtain' supports
  3523 generalized existence reasoning;
  3524 
  3525 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3526 support accumulation of results, without applying any rules yet;
  3527 useful to collect intermediate results without explicit name
  3528 references, and for use with transitivity rules with more than 2
  3529 premises;
  3530 
  3531 * Isar/Pure: scalable support for case-analysis type proofs: new
  3532 'case' language element refers to local contexts symbolically, as
  3533 produced by certain proof methods; internally, case names are attached
  3534 to theorems as "tags";
  3535 
  3536 * Isar/Pure: theory command 'hide' removes declarations from
  3537 class/type/const name spaces;
  3538 
  3539 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3540 indicate potential overloading;
  3541 
  3542 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3543 
  3544 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3545 "{a,b,c}" instead of {a,b,c};
  3546 
  3547 * Isar/Pure now provides its own version of intro/elim/dest
  3548 attributes; useful for building new logics, but beware of confusion
  3549 with the version in Provers/classical;
  3550 
  3551 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3552 case name 'antecedent';
  3553 
  3554 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3555 to the current context is now done automatically);
  3556 
  3557 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3558 for definining proof methods in ML;
  3559 
  3560 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3561 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3562 most cases, one should have to change intro!! to intro? only);
  3563 replaced "delrule" by "rule del";
  3564 
  3565 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3566 'symmetric' attribute (the latter supercedes [RS sym]);
  3567 
  3568 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3569 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3570 well (including splits);
  3571 
  3572 * Isar/Provers: Simplifier and Classical methods now support all kind
  3573 of modifiers used in the past, including 'cong', 'iff', etc.
  3574 
  3575 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3576 of Simplifier and Classical reasoner);
  3577 
  3578 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3579 now support named cases; major packages (inductive, datatype, primrec,
  3580 recdef) support case names and properly name parameters;
  3581 
  3582 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3583 monotonicity conditions are extracted to be proven at end of
  3584 calculations;
  3585 
  3586 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3587 method anyway;
  3588 
  3589 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3590 split_if split_if_asm; datatype package provides theorems foo.splits =
  3591 foo.split foo.split_asm for each datatype;
  3592 
  3593 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3594 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3595 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3596 use "(cases (simplified))" method in proper proof texts);
  3597 
  3598 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3599 
  3600 * Isar: names of theorems etc. may be natural numbers as well;
  3601 
  3602 * Isar: 'pr' command: optional arguments for goals_limit and
  3603 ProofContext.prems_limit; no longer prints theory contexts, but only
  3604 proof states;
  3605 
  3606 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3607 additional print modes to be specified; e.g. "pr(latex)" will print
  3608 proof state according to the Isabelle LaTeX style;
  3609 
  3610 * Isar: improved support for emulating tactic scripts, including proof
  3611 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3612 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3613 (for HOL datatypes);
  3614 
  3615 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3616 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3617 'proof method scripts' have to be in depth-first order;
  3618 
  3619 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3620 
  3621 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3622 should instead use individual commands for printing items
  3623 (print_commands, print_methods etc.);
  3624 
  3625 * Isar: added 'nothing' --- the empty list of theorems;
  3626 
  3627 
  3628 *** HOL ***
  3629 
  3630 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3631 corresponding virtual machine and a specification of its bytecode
  3632 verifier and a lightweight bytecode verifier, including proofs of
  3633 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3634 Cornelia Pusch (see also the homepage of project Bali at
  3635 http://isabelle.in.tum.de/Bali/);
  3636 
  3637 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3638 Clemens Ballarin;
  3639 
  3640 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3641 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3642 Rasmussen;
  3643 
  3644 * HOL/Lattice: fundamental concepts of lattice theory and order
  3645 structures, including duals, properties of bounds versus algebraic
  3646 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3647 Theorem for complete lattices etc.; may also serve as a demonstration
  3648 for abstract algebraic reasoning using axiomatic type classes, and
  3649 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3650 
  3651 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3652 von Oheimb;
  3653 
  3654 * HOL/IMPP: extension of IMP with local variables and mutually
  3655 recursive procedures, by David von Oheimb;
  3656 
  3657 * HOL/Lambda: converted into new-style theory and document;
  3658 
  3659 * HOL/ex/Multiquote: example of multiple nested quotations and
  3660 anti-quotations -- basically a generalized version of de-Bruijn
  3661 representation; very useful in avoiding lifting of operations;
  3662 
  3663 * HOL/record: added general record equality rule to simpset; fixed
  3664 select-update simplification procedure to handle extended records as
  3665 well; admit "r" as field name;
  3666 
  3667 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3668 other numeric types and also as the identity of groups, rings, etc.;
  3669 
  3670 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3671 Types nat and int belong to this axclass;
  3672 
  3673 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3674    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3675    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3676   two terms #m*u and #n*u are replaced by #(m+n)*u
  3677     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3678   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3679     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3680 
  3681 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3682 powerful prover for predicate logic but knows nothing of clasets; see
  3683 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3684 
  3685 * HOL: new version of "case_tac" subsumes both boolean case split and
  3686 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3687 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3688 
  3689 * HOL: simplification no longer dives into case-expressions: only the
  3690 selector expression is simplified, but not the remaining arms; to
  3691 enable full simplification of case-expressions for datatype t, you may
  3692 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3693 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3694 
  3695 * HOL/recdef: the recursion equations generated by 'recdef' for
  3696 function 'f' are now called f.simps instead of f.rules; if all
  3697 termination conditions are proved automatically, these simplification
  3698 rules are added to the simpset, as in primrec; rules may be named
  3699 individually as well, resulting in a separate list of theorems for
  3700 each equation;
  3701 
  3702 * HOL/While is a new theory that provides a while-combinator. It
  3703 permits the definition of tail-recursive functions without the
  3704 provision of a termination measure. The latter is necessary once the
  3705 invariant proof rule for while is applied.
  3706 
  3707 * HOL: new (overloaded) notation for the set of elements below/above
  3708 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3709 
  3710 * HOL: theorems impI, allI, ballI bound as "strip";
  3711 
  3712 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3713 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3714 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3715 
  3716 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3717 
  3718 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3719 main HOL, but was unused);
  3720 
  3721 * HOL: fewer consts declared as global (e.g. have to refer to
  3722 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3723 
  3724 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3725 in case of overlap with user translations (e.g. judgements over
  3726 tuples); (note that the underlying logical represenation is still
  3727 bogus);
  3728 
  3729 
  3730 *** ZF ***
  3731 
  3732 * ZF: simplification automatically cancels common terms in arithmetic
  3733 expressions over nat and int;
  3734 
  3735 * ZF: new treatment of nat to minimize type-checking: all operators
  3736 coerce their operands to a natural number using the function natify,
  3737 making the algebraic laws unconditional;
  3738 
  3739 * ZF: as above, for int: operators coerce their operands to an integer
  3740 using the function intify;
  3741 
  3742 * ZF: the integer library now contains many of the usual laws for the
  3743 orderings, including $<=, and monotonicity laws for $+ and $*;
  3744 
  3745 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3746 simplification;
  3747 
  3748 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3749 to the simplifier and classical reasoner simultaneously;
  3750 
  3751 
  3752 *** General ***
  3753 
  3754 * Provers: blast_tac now handles actual object-logic rules as
  3755 assumptions; note that auto_tac uses blast_tac internally as well;
  3756 
  3757 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3758 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3759 
  3760 * Provers: delrules now handles destruct rules as well (no longer need
  3761 explicit make_elim);
  3762 
  3763 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3764   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3765 use instead the strong form,
  3766   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3767 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3768 from destruct-rules;
  3769 
  3770 * Provers: Simplifier.easy_setup provides a fast path to basic
  3771 Simplifier setup for new object-logics;
  3772 
  3773 * Pure: AST translation rules no longer require constant head on LHS;
  3774 
  3775 * Pure: improved name spaces: ambiguous output is qualified; support
  3776 for hiding of names;
  3777 
  3778 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3779 XSYMBOL_HOME; no longer need to do manual configuration in most
  3780 situations;
  3781 
  3782 * system: compression of ML heaps images may now be controlled via -c
  3783 option of isabelle and isatool usedir (currently only observed by
  3784 Poly/ML);
  3785 
  3786 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3787 useful for remote X11);
  3788 
  3789 * system: provide TAGS file for Isabelle sources;
  3790 
  3791 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3792 order;
  3793 
  3794 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3795 timing flag supersedes proof_timing and Toplevel.trace;
  3796 
  3797 * ML: new combinators |>> and |>>> for incremental transformations
  3798 with secondary results (e.g. certain theory extensions):
  3799 
  3800 * ML: PureThy.add_defs gets additional argument to indicate potential
  3801 overloading (usually false);
  3802 
  3803 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3804 results;
  3805 
  3806 
  3807 
  3808 New in Isabelle99 (October 1999)
  3809 --------------------------------
  3810 
  3811 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3812 
  3813 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3814 are no longer simplified.  (This allows the simplifier to unfold recursive
  3815 functional programs.)  To restore the old behaviour, declare
  3816 
  3817     Delcongs [if_weak_cong];
  3818 
  3819 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3820 complement;
  3821 
  3822 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3823 
  3824 * HOL/datatype: mutual_induct_tac no longer exists --
  3825   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3826 
  3827 * HOL/typedef: fixed type inference for representing set; type
  3828 arguments now have to occur explicitly on the rhs as type constraints;
  3829 
  3830 * ZF: The con_defs part of an inductive definition may no longer refer
  3831 to constants declared in the same theory;
  3832 
  3833 * HOL, ZF: the function mk_cases, generated by the inductive
  3834 definition package, has lost an argument.  To simplify its result, it
  3835 uses the default simpset instead of a supplied list of theorems.
  3836 
  3837 * HOL/List: the constructors of type list are now Nil and Cons;
  3838 
  3839 * Simplifier: the type of the infix ML functions
  3840         setSSolver addSSolver setSolver addSolver
  3841 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3842 for packaging solvers. A solver is created via
  3843         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3844 where the string argument is only a comment.
  3845 
  3846 
  3847 *** Proof tools ***
  3848 
  3849 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3850 decision procedure for linear arithmetic. Currently it is used for
  3851 types `nat', `int', and `real' in HOL (see below); it can, should and
  3852 will be instantiated for other types and logics as well.
  3853 
  3854 * The simplifier now accepts rewrite rules with flexible heads, eg
  3855      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3856   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3857   matching.
  3858 
  3859 
  3860 *** General ***
  3861 
  3862 * New Isabelle/Isar subsystem provides an alternative to traditional
  3863 tactical theorem proving; together with the ProofGeneral/isar user
  3864 interface it offers an interactive environment for developing human
  3865 readable proof documents (Isar == Intelligible semi-automated
  3866 reasoning); for further information see isatool doc isar-ref,
  3867 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3868 
  3869 * improved and simplified presentation of theories: better HTML markup
  3870 (including colors), graph views in several sizes; isatool usedir now
  3871 provides a proper interface for user theories (via -P option); actual
  3872 document preparation based on (PDF)LaTeX is available as well (for
  3873 new-style theories only); see isatool doc system for more information;
  3874 
  3875 * native support for Proof General, both for classic Isabelle and
  3876 Isabelle/Isar;
  3877 
  3878 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3879 using the graph browser tool;
  3880 
  3881 * Isabelle manuals now also available as PDF;
  3882 
  3883 * theory loader rewritten from scratch (may not be fully
  3884 bug-compatible); old loadpath variable has been replaced by show_path,
  3885 add_path, del_path, reset_path functions; new operations such as
  3886 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3887 isatool doc ref);
  3888 
  3889 * improved isatool install: option -k creates KDE application icon,
  3890 option -p DIR installs standalone binaries;
  3891 
  3892 * added ML_PLATFORM setting (useful for cross-platform installations);
  3893 more robust handling of platform specific ML images for SML/NJ;
  3894 
  3895 * the settings environment is now statically scoped, i.e. it is never
  3896 created again in sub-processes invoked from isabelle, isatool, or
  3897 Isabelle;
  3898 
  3899 * path element specification '~~' refers to '$ISABELLE_HOME';
  3900 
  3901 * in locales, the "assumes" and "defines" parts may be omitted if
  3902 empty;
  3903 
  3904 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3905 long arrows);
  3906 
  3907 * new print_mode "HTML";
  3908 
  3909 * new flag show_tags controls display of tags of theorems (which are
  3910 basically just comments that may be attached by some tools);
  3911 
  3912 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3913 mode and goal output format:
  3914 
  3915 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3916 244c244
  3917 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3918 ---
  3919 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3920 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3921 181c181
  3922 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3923 ---
  3924 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3925 
  3926 * function bind_thms stores lists of theorems (cf. bind_thm);
  3927 
  3928 * new shorthand tactics ftac, eatac, datac, fatac;
  3929 
  3930 * qed (and friends) now accept "" as result name; in that case the
  3931 theorem is not stored, but proper checks and presentation of the
  3932 result still apply;
  3933 
  3934 * theorem database now also indexes constants "Trueprop", "all",
  3935 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3936 
  3937 
  3938 *** HOL ***
  3939 
  3940 ** HOL arithmetic **
  3941 
  3942 * There are now decision procedures for linear arithmetic over nat and
  3943 int:
  3944 
  3945 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3946 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3947 are treated as atomic; subformulae not involving type `nat' or `int'
  3948 are ignored; quantified subformulae are ignored unless they are
  3949 positive universal or negative existential. The tactic has to be
  3950 invoked by hand and can be a little bit slow. In particular, the
  3951 running time is exponential in the number of occurrences of `min' and
  3952 `max', and `-' on `nat'.
  3953 
  3954 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3955 (negated) (in)equalities among the premises and the conclusion into
  3956 account (i.e. no compound formulae) and does not know about `min' and
  3957 `max', and `-' on `nat'. It is fast and is used automatically by the
  3958 simplifier.
  3959 
  3960 NB: At the moment, these decision procedures do not cope with mixed
  3961 nat/int formulae where the two parts interact, such as `m < n ==>
  3962 int(m) < int(n)'.
  3963 
  3964 * HOL/Numeral provides a generic theory of numerals (encoded
  3965 efficiently as bit strings); setup for types nat/int/real is in place;
  3966 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3967 int, existing theories and proof scripts may require a few additional
  3968 type constraints;
  3969 
  3970 * integer division and remainder can now be performed on constant
  3971 arguments;
  3972 
  3973 * many properties of integer multiplication, division and remainder
  3974 are now available;
  3975 
  3976 * An interface to the Stanford Validity Checker (SVC) is available through the
  3977 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3978 are proved automatically.  SVC must be installed separately, and its results
  3979 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3980 invocation of the underlying oracle).  For SVC see
  3981   http://verify.stanford.edu/SVC
  3982 
  3983 * IsaMakefile: the HOL-Real target now builds an actual image;
  3984 
  3985 
  3986 ** HOL misc **
  3987 
  3988 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3989 (in Isabelle/Isar) -- by Gertrud Bauer;
  3990 
  3991 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3992 analysis for assembly languages with subtypes;
  3993 
  3994 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3995 -- avoids syntactic ambiguities and treats state, transition, and
  3996 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3997 changed syntax and (many) tactics;
  3998 
  3999 * HOL/inductive: Now also handles more general introduction rules such
  4000   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4001   theorems are now maintained within the theory (maintained via the
  4002   "mono" attribute);
  4003 
  4004 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4005   (using function types) such as
  4006 
  4007   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4008 
  4009 * HOL/record: record_simproc (part of the default simpset) takes care
  4010 of selectors applied to updated records; record_split_tac is no longer
  4011 part of the default claset; update_defs may now be removed from the
  4012 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4013 
  4014   claset_ref () := claset() addSWrapper record_split_wrapper;
  4015   Delsimprocs [record_simproc]
  4016 
  4017 * HOL/typedef: fixed type inference for representing set; type
  4018 arguments now have to occur explicitly on the rhs as type constraints;
  4019 
  4020 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4021 names rather than an ML expression;
  4022 
  4023 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4024 supplied later.  Program schemes can be defined, such as
  4025     "While B C s = (if B s then While B C (C s) else s)"
  4026 where the well-founded relation can be chosen after B and C have been given.
  4027 
  4028 * HOL/List: the constructors of type list are now Nil and Cons;
  4029 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4030 course, ML tools referring to List.list.op # etc. have to be adapted;
  4031 
  4032 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4033 disabled by default; run isabelle with option -m HOL to get back to
  4034 the original Gordon/HOL-style output;
  4035 
  4036 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4037 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4038 
  4039 * HOL basic syntax simplified (more orthogonal): all variants of
  4040 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4041 Eps operator is provided as well: "SOME x. P[x]";
  4042 
  4043 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4044 
  4045 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4046 thus available for user theories;
  4047 
  4048 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4049 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4050 time;
  4051 
  4052 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4053 several times and then mp;
  4054 
  4055 
  4056 *** LK ***
  4057 
  4058 * the notation <<...>> is now available as a notation for sequences of
  4059 formulas;
  4060 
  4061 * the simplifier is now installed
  4062 
  4063 * the axiom system has been generalized (thanks to Soren Heilmann)
  4064 
  4065 * the classical reasoner now has a default rule database
  4066 
  4067 
  4068 *** ZF ***
  4069 
  4070 * new primrec section allows primitive recursive functions to be given
  4071 directly (as in HOL) over datatypes and the natural numbers;
  4072 
  4073 * new tactics induct_tac and exhaust_tac for induction (or case
  4074 analysis) over datatypes and the natural numbers;
  4075 
  4076 * the datatype declaration of type T now defines the recursor T_rec;
  4077 
  4078 * simplification automatically does freeness reasoning for datatype
  4079 constructors;
  4080 
  4081 * automatic type-inference, with AddTCs command to insert new
  4082 type-checking rules;
  4083 
  4084 * datatype introduction rules are now added as Safe Introduction rules
  4085 to the claset;
  4086 
  4087 * the syntax "if P then x else y" is now available in addition to
  4088 if(P,x,y);
  4089 
  4090 
  4091 *** Internal programming interfaces ***
  4092 
  4093 * tuned simplifier trace output; new flag debug_simp;
  4094 
  4095 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4096 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4097 
  4098 * AxClass.axclass_tac lost the theory argument;
  4099 
  4100 * tuned current_goals_markers semantics: begin / end goal avoids
  4101 printing empty lines;
  4102 
  4103 * removed prs and prs_fn hook, which was broken because it did not
  4104 include \n in its semantics, forcing writeln to add one
  4105 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4106 string -> unit if you really want to output text without newline;
  4107 
  4108 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4109 plain output, interface builders may have to enable 'isabelle_font'
  4110 mode to get Isabelle font glyphs as before;
  4111 
  4112 * refined token_translation interface; INCOMPATIBILITY: output length
  4113 now of type real instead of int;
  4114 
  4115 * theory loader actions may be traced via new ThyInfo.add_hook
  4116 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4117 your own database of information attached to *whole* theories -- as
  4118 opposed to intra-theory data slots offered via TheoryDataFun;
  4119 
  4120 * proper handling of dangling sort hypotheses (at last!);
  4121 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4122 extra sort hypotheses that can be witnessed from the type signature;
  4123 the force_strip_shyps flag is gone, any remaining shyps are simply
  4124 left in the theorem (with a warning issued by strip_shyps_warning);
  4125 
  4126 
  4127 
  4128 New in Isabelle98-1 (October 1998)
  4129 ----------------------------------
  4130 
  4131 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4132 
  4133 * several changes of automated proof tools;
  4134 
  4135 * HOL: major changes to the inductive and datatype packages, including
  4136 some minor incompatibilities of theory syntax;
  4137 
  4138 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4139 called `inj_on';
  4140 
  4141 * HOL: removed duplicate thms in Arith:
  4142   less_imp_add_less  should be replaced by  trans_less_add1
  4143   le_imp_add_le      should be replaced by  trans_le_add1
  4144 
  4145 * HOL: unary minus is now overloaded (new type constraints may be
  4146 required);
  4147 
  4148 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4149 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4150 now taken as an integer constant.
  4151 
  4152 * Pure: ML function 'theory_of' renamed to 'theory';
  4153 
  4154 
  4155 *** Proof tools ***
  4156 
  4157 * Simplifier:
  4158   1. Asm_full_simp_tac is now more aggressive.
  4159      1. It will sometimes reorient premises if that increases their power to
  4160         simplify.
  4161      2. It does no longer proceed strictly from left to right but may also
  4162         rotate premises to achieve further simplification.
  4163      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4164      old Asm_full_simp_tac in that it does not rotate premises.
  4165   2. The simplifier now knows a little bit about nat-arithmetic.
  4166 
  4167 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4168 allows for selected deletion of wrappers, by introduction of names for
  4169 wrapper functionals.  This implies that addbefore, addSbefore,
  4170 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4171 and that adding two tactics with the same name overwrites the first
  4172 one (emitting a warning).
  4173   type wrapper = (int -> tactic) -> (int -> tactic)
  4174   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4175   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4176   delWrapper, delSWrapper: claset *  string            -> claset
  4177   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4178 
  4179 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4180 semantics; addbefore now affects only the unsafe part of step_tac
  4181 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4182 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4183 by Force_tac;
  4184 
  4185 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4186 compWrapper; added safe wrapper (and access functions for it);
  4187 
  4188 * HOL/split_all_tac is now much faster and fails if there is nothing
  4189 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4190 and the names of the automatically generated variables have changed.
  4191 split_all_tac has moved within claset() from unsafe wrappers to safe
  4192 wrappers, which means that !!-bound variables are split much more
  4193 aggressively, and safe_tac and clarify_tac now split such variables.
  4194 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4195 Note: the same holds for record_split_tac, which does the job of
  4196 split_all_tac for record fields.
  4197 
  4198 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4199 permanently to the default simpset using Addsplits just like
  4200 Addsimps. They can be removed via Delsplits just like
  4201 Delsimps. Lower-case versions are also available.
  4202 
  4203 * HOL/Simplifier: The rule split_if is now part of the default
  4204 simpset. This means that the simplifier will eliminate all occurrences
  4205 of if-then-else in the conclusion of a goal. To prevent this, you can
  4206 either remove split_if completely from the default simpset by
  4207 `Delsplits [split_if]' or remove it in a specific call of the
  4208 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4209 other case splitting rules to/from the default simpset: every datatype
  4210 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4211 t is the name of the datatype).
  4212 
  4213 * Classical reasoner / Simplifier combination: new force_tac (and
  4214 derivatives Force_tac, force) combines rewriting and classical
  4215 reasoning (and whatever other tools) similarly to auto_tac, but is
  4216 aimed to solve the given subgoal completely.
  4217 
  4218 
  4219 *** General ***
  4220 
  4221 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4222 and `goalw': the theory is no longer needed as an explicit argument -
  4223 the current theory context is used; assumptions are no longer returned
  4224 at the ML-level unless one of them starts with ==> or !!; it is
  4225 recommended to convert to these new commands using isatool fixgoal
  4226 (backup your sources first!);
  4227 
  4228 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4229 the current theory context, and 'theory' to lookup stored theories;
  4230 
  4231 * new theory section 'locale' for declaring constants, assumptions and
  4232 definitions that have local scope;
  4233 
  4234 * new theory section 'nonterminals' for purely syntactic types;
  4235 
  4236 * new theory section 'setup' for generic ML setup functions
  4237 (e.g. package initialization);
  4238 
  4239 * the distribution now includes Isabelle icons: see
  4240 lib/logo/isabelle-{small,tiny}.xpm;
  4241 
  4242 * isatool install - install binaries with absolute references to
  4243 ISABELLE_HOME/bin;
  4244 
  4245 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4246 
  4247 * print mode 'emacs' reserved for Isamode;
  4248 
  4249 * support multiple print (ast) translations per constant name;
  4250 
  4251 * theorems involving oracles are now printed with a suffixed [!];
  4252 
  4253 
  4254 *** HOL ***
  4255 
  4256 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4257 
  4258 * HOL/inductive package reorganized and improved: now supports mutual
  4259 definitions such as
  4260 
  4261   inductive EVEN ODD
  4262     intrs
  4263       null "0 : EVEN"
  4264       oddI "n : EVEN ==> Suc n : ODD"
  4265       evenI "n : ODD ==> Suc n : EVEN"
  4266 
  4267 new theorem list "elims" contains an elimination rule for each of the
  4268 recursive sets; inductive definitions now handle disjunctive premises
  4269 correctly (also ZF);
  4270 
  4271 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4272 "mutual_induct" no longer exists - the induction rule is always
  4273 contained in "induct";
  4274 
  4275 
  4276 * HOL/datatype package re-implemented and greatly improved: now
  4277 supports mutually recursive datatypes such as
  4278 
  4279   datatype
  4280     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4281             | SUM ('a aexp) ('a aexp)
  4282             | DIFF ('a aexp) ('a aexp)
  4283             | NUM 'a
  4284   and
  4285     'a bexp = LESS ('a aexp) ('a aexp)
  4286             | AND ('a bexp) ('a bexp)
  4287             | OR ('a bexp) ('a bexp)
  4288 
  4289 as well as indirectly recursive datatypes such as
  4290 
  4291   datatype
  4292     ('a, 'b) term = Var 'a
  4293                   | App 'b ((('a, 'b) term) list)
  4294 
  4295 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4296 induction on mutually / indirectly recursive datatypes.
  4297 
  4298 Primrec equations are now stored in theory and can be accessed via
  4299 <function_name>.simps.
  4300 
  4301 INCOMPATIBILITIES:
  4302 
  4303   - Theories using datatypes must now have theory Datatype as an
  4304     ancestor.
  4305   - The specific <typename>.induct_tac no longer exists - use the
  4306     generic induct_tac instead.
  4307   - natE has been renamed to nat.exhaust - use exhaust_tac
  4308     instead of res_inst_tac ... natE. Note that the variable
  4309     names in nat.exhaust differ from the names in natE, this
  4310     may cause some "fragile" proofs to fail.
  4311   - The theorems split_<typename>_case and split_<typename>_case_asm
  4312     have been renamed to <typename>.split and <typename>.split_asm.
  4313   - Since default sorts of type variables are now handled correctly,
  4314     some datatype definitions may have to be annotated with explicit
  4315     sort constraints.
  4316   - Primrec definitions no longer require function name and type
  4317     of recursive argument.
  4318 
  4319 Consider using isatool fixdatatype to adapt your theories and proof
  4320 scripts to the new package (backup your sources first!).
  4321 
  4322 
  4323 * HOL/record package: considerably improved implementation; now
  4324 includes concrete syntax for record types, terms, updates; theorems
  4325 for surjective pairing and splitting !!-bound record variables; proof
  4326 support is as follows:
  4327 
  4328   1) standard conversions (selectors or updates applied to record
  4329 constructor terms) are part of the standard simpset;
  4330 
  4331   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4332 made part of standard simpset and claset via addIffs;
  4333 
  4334   3) a tactic for record field splitting (record_split_tac) is part of
  4335 the standard claset (addSWrapper);
  4336 
  4337 To get a better idea about these rules you may retrieve them via
  4338 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4339 the name of your record type.
  4340 
  4341 The split tactic 3) conceptually simplifies by the following rule:
  4342 
  4343   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4344 
  4345 Thus any record variable that is bound by meta-all will automatically
  4346 blow up into some record constructor term, consequently the
  4347 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4348 solve record problems automatically.
  4349 
  4350 
  4351 * reorganized the main HOL image: HOL/Integ and String loaded by
  4352 default; theory Main includes everything;
  4353 
  4354 * automatic simplification of integer sums and comparisons, using cancellation;
  4355 
  4356 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4357 
  4358 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4359 
  4360 * many new identities for unions, intersections, set difference, etc.;
  4361 
  4362 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4363 called split_if, split_split, split_sum_case and split_nat_case (to go
  4364 with add/delsplits);
  4365 
  4366 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4367 (?x::unit) = (); this is made part of the default simpset, which COULD
  4368 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4369 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4370 unit_abs_eta_conv is added in order to counter the effect of
  4371 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4372 %u.f();
  4373 
  4374 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4375 makes more sense);
  4376 
  4377 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4378   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4379   disjointness reasoning but breaking a few old proofs.
  4380 
  4381 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4382 to 'converse' from 'inverse' (for compatibility with ZF and some
  4383 literature);
  4384 
  4385 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4386 the well-founded relation;
  4387 
  4388 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4389     Compl A.  The "Compl" syntax remains available as input syntax for this
  4390     release ONLY.
  4391 
  4392 * HOL/Update: new theory of function updates:
  4393     f(a:=b) == %x. if x=a then b else f x
  4394 may also be iterated as in f(a:=b,c:=d,...);
  4395 
  4396 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4397 
  4398 * HOL/List:
  4399   - new function list_update written xs[i:=v] that updates the i-th
  4400     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4401   - new function `upt' written [i..j(] which generates the list
  4402     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4403     bound write [i..j], which is a shorthand for [i..j+1(].
  4404   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4405 
  4406 * HOL/Arith:
  4407   - removed 'pred' (predecessor) function;
  4408   - generalized some theorems about n-1;
  4409   - many new laws about "div" and "mod";
  4410   - new laws about greatest common divisors (see theory ex/Primes);
  4411 
  4412 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4413 instead of "inverse";
  4414 
  4415 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4416   of the multiset ordering;
  4417 
  4418 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4419   (not included by default);
  4420 
  4421 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4422 
  4423 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4424   programs, i.e. different program variables may have different types.
  4425 
  4426 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4427   [previously, this check worked only if the rewrite rule was unconditional]
  4428   Now rew can involve either definitions or equalities (either == or =).
  4429 
  4430 
  4431 *** ZF ***
  4432 
  4433 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4434   only the theorems proved on ZF.ML;
  4435 
  4436 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4437   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4438   disjointness reasoning but breaking a few old proofs.
  4439 
  4440 * ZF/Update: new theory of function updates
  4441     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4442   may also be iterated as in f(a:=b,c:=d,...);
  4443 
  4444 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4445 
  4446 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4447   [previously, this check worked only if the rewrite rule was unconditional]
  4448   Now rew can involve either definitions or equalities (either == or =).
  4449 
  4450 * case_tac provided for compatibility with HOL
  4451     (like the old excluded_middle_tac, but with subgoals swapped)
  4452 
  4453 
  4454 *** Internal programming interfaces ***
  4455 
  4456 * Pure: several new basic modules made available for general use, see
  4457 also src/Pure/README;
  4458 
  4459 * improved the theory data mechanism to support encapsulation (data
  4460 kind name replaced by private Object.kind, acting as authorization
  4461 key); new type-safe user interface via functor TheoryDataFun; generic
  4462 print_data function becomes basically useless;
  4463 
  4464 * removed global_names compatibility flag -- all theory declarations
  4465 are qualified by default;
  4466 
  4467 * module Pure/Syntax now offers quote / antiquote translation
  4468 functions (useful for Hoare logic etc. with implicit dependencies);
  4469 see HOL/ex/Antiquote for an example use;
  4470 
  4471 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4472 cterm -> thm;
  4473 
  4474 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4475 subgoal;
  4476 
  4477 * Display.print_goals function moved to Locale.print_goals;
  4478 
  4479 * standard print function for goals supports current_goals_markers
  4480 variable for marking begin of proof, end of proof, start of goal; the
  4481 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4482 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4483 for example;
  4484 
  4485 
  4486 
  4487 New in Isabelle98 (January 1998)
  4488 --------------------------------
  4489 
  4490 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4491 
  4492 * changed lexical syntax of terms / types: dots made part of long
  4493 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4494 
  4495 * simpset (and claset) reference variable replaced by functions
  4496 simpset / simpset_ref;
  4497 
  4498 * no longer supports theory aliases (via merge) and non-trivial
  4499 implicit merge of thms' signatures;
  4500 
  4501 * most internal names of constants changed due to qualified names;
  4502 
  4503 * changed Pure/Sequence interface (see Pure/seq.ML);
  4504 
  4505 
  4506 *** General Changes ***
  4507 
  4508 * hierachically structured name spaces (for consts, types, axms, thms
  4509 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4510 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4511 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4512 long_names for fully qualified output names; NOTE: ML programs
  4513 (special tactics, packages etc.) referring to internal names may have
  4514 to be adapted to cope with fully qualified names; in case of severe
  4515 backward campatibility problems try setting 'global_names' at compile
  4516 time to have enrything declared within a flat name space; one may also
  4517 fine tune name declarations in theories via the 'global' and 'local'
  4518 section;
  4519 
  4520 * reimplemented the implicit simpset and claset using the new anytype
  4521 data filed in signatures; references simpset:simpset ref etc. are
  4522 replaced by functions simpset:unit->simpset and
  4523 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4524 to patch your ML files accordingly;
  4525 
  4526 * HTML output now includes theory graph data for display with Java
  4527 applet or isatool browser; data generated automatically via isatool
  4528 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4529 
  4530 * defs may now be conditional; improved rewrite_goals_tac to handle
  4531 conditional equations;
  4532 
  4533 * defs now admits additional type arguments, using TYPE('a) syntax;
  4534 
  4535 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4536 creates a new theory node; implicit merge of thms' signatures is
  4537 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4538 transfer:theory->thm->thm in (rare) cases;
  4539 
  4540 * improved handling of draft signatures / theories; draft thms (and
  4541 ctyps, cterms) are automatically promoted to real ones;
  4542 
  4543 * slightly changed interfaces for oracles: admit many per theory, named
  4544 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4545 
  4546 * print_goals: optional output of const types (set show_consts and
  4547 show_types);
  4548 
  4549 * improved output of warnings (###) and errors (***);
  4550 
  4551 * subgoal_tac displays a warning if the new subgoal has type variables;
  4552 
  4553 * removed old README and Makefiles;
  4554 
  4555 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4556 
  4557 * removed obsolete init_pps and init_database;
  4558 
  4559 * deleted the obsolete tactical STATE, which was declared by
  4560     fun STATE tacfun st = tacfun st st;
  4561 
  4562 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4563 (which abbreviates $HOME);
  4564 
  4565 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4566 use isatool fixseq to adapt your ML programs (this works for fully
  4567 qualified references to the Sequence structure only!);
  4568 
  4569 * use_thy no longer requires writable current directory; it always
  4570 reloads .ML *and* .thy file, if either one is out of date;
  4571 
  4572 
  4573 *** Classical Reasoner ***
  4574 
  4575 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4576 tactics that use classical reasoning to simplify a subgoal without
  4577 splitting it into several subgoals;
  4578 
  4579 * Safe_tac: like safe_tac but uses the default claset;
  4580 
  4581 
  4582 *** Simplifier ***
  4583 
  4584 * added simplification meta rules:
  4585     (asm_)(full_)simplify: simpset -> thm -> thm;
  4586 
  4587 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4588 logics (again);
  4589 
  4590 * added prems argument to simplification procedures;
  4591 
  4592 * HOL, FOL, ZF: added infix function `addsplits':
  4593   instead of `<simpset> setloop (split_tac <thms>)'
  4594   you can simply write `<simpset> addsplits <thms>'
  4595 
  4596 
  4597 *** Syntax ***
  4598 
  4599 * TYPE('a) syntax for type reflection terms;
  4600 
  4601 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4602 
  4603 * pretty printer: changed order of mixfix annotation preference (again!);
  4604 
  4605 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4606 
  4607 
  4608 *** HOL ***
  4609 
  4610 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4611   with `addloop' of the simplifier to faciliate case splitting in premises.
  4612 
  4613 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4614 
  4615 * HOL/Auth: new protocol proofs including some for the Internet
  4616   protocol TLS;
  4617 
  4618 * HOL/Map: new theory of `maps' a la VDM;
  4619 
  4620 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4621 cancelling out common nat summands from =, <, <= (in)equalities, or
  4622 differences; simplification procedures nat_cancel_factor for
  4623 cancelling common factor from =, <, <= (in)equalities over natural
  4624 sums; nat_cancel contains both kinds of procedures, it is installed by
  4625 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4626 
  4627 * HOL/simplifier: terms of the form
  4628   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4629   are rewritten to
  4630   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4631   and those of the form
  4632   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4633   are rewritten to
  4634   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4635 
  4636 * HOL/datatype
  4637   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4638 
  4639   P(t_case f1 ... fn x) =
  4640      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4641         ...
  4642        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4643      )
  4644 
  4645   and a theorem `split_t_case_asm' of the form
  4646 
  4647   P(t_case f1 ... fn x) =
  4648     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4649         ...
  4650        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4651      )
  4652   which can be added to a simpset via `addsplits'. The existing theorems
  4653   expand_list_case and expand_option_case have been renamed to
  4654   split_list_case and split_option_case.
  4655 
  4656 * HOL/Arithmetic:
  4657   - `pred n' is automatically converted to `n-1'.
  4658     Users are strongly encouraged not to use `pred' any longer,
  4659     because it will disappear altogether at some point.
  4660   - Users are strongly encouraged to write "0 < n" rather than
  4661     "n ~= 0". Theorems and proof tools have been modified towards this
  4662     `standard'.
  4663 
  4664 * HOL/Lists:
  4665   the function "set_of_list" has been renamed "set" (and its theorems too);
  4666   the function "nth" now takes its arguments in the reverse order and
  4667   has acquired the infix notation "!" as in "xs!n".
  4668 
  4669 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4670 
  4671 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4672   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4673 
  4674 * HOL/record: extensible records with schematic structural subtyping
  4675 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4676 still lacks various theorems and concrete record syntax;
  4677 
  4678 
  4679 *** HOLCF ***
  4680 
  4681 * removed "axioms" and "generated by" sections;
  4682 
  4683 * replaced "ops" section by extended "consts" section, which is capable of
  4684   handling the continuous function space "->" directly;
  4685 
  4686 * domain package:
  4687   . proves theorems immediately and stores them in the theory,
  4688   . creates hierachical name space,
  4689   . now uses normal mixfix annotations (instead of cinfix...),
  4690   . minor changes to some names and values (for consistency),
  4691   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4692   . separator between mutual domain defs: changed "," to "and",
  4693   . improved handling of sort constraints;  now they have to
  4694     appear on the left-hand side of the equations only;
  4695 
  4696 * fixed LAM <x,y,zs>.b syntax;
  4697 
  4698 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4699 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4700 
  4701 
  4702 *** FOL and ZF ***
  4703 
  4704 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4705   with `addloop' of the simplifier to faciliate case splitting in premises.
  4706 
  4707 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4708 in HOL, they strip ALL and --> from proved theorems;
  4709 
  4710 
  4711 
  4712 New in Isabelle94-8 (May 1997)
  4713 ------------------------------
  4714 
  4715 *** General Changes ***
  4716 
  4717 * new utilities to build / run / maintain Isabelle etc. (in parts
  4718 still somewhat experimental); old Makefiles etc. still functional;
  4719 
  4720 * new 'Isabelle System Manual';
  4721 
  4722 * INSTALL text, together with ./configure and ./build scripts;
  4723 
  4724 * reimplemented type inference for greater efficiency, better error
  4725 messages and clean internal interface;
  4726 
  4727 * prlim command for dealing with lots of subgoals (an easier way of
  4728 setting goals_limit);
  4729 
  4730 
  4731 *** Syntax ***
  4732 
  4733 * supports alternative (named) syntax tables (parser and pretty
  4734 printer); internal interface is provided by add_modesyntax(_i);
  4735 
  4736 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4737 be used in conjunction with the Isabelle symbol font; uses the
  4738 "symbols" syntax table;
  4739 
  4740 * added token_translation interface (may translate name tokens in
  4741 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4742 the current print_mode); IMPORTANT: user print translation functions
  4743 are responsible for marking newly introduced bounds
  4744 (Syntax.mark_boundT);
  4745 
  4746 * token translations for modes "xterm" and "xterm_color" that display
  4747 names in bold, underline etc. or colors (which requires a color
  4748 version of xterm);
  4749 
  4750 * infixes may now be declared with names independent of their syntax;
  4751 
  4752 * added typed_print_translation (like print_translation, but may
  4753 access type of constant);
  4754 
  4755 
  4756 *** Classical Reasoner ***
  4757 
  4758 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4759 some limitations.  Blast_tac...
  4760   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4761   + ignores elimination rules that don't have the correct format
  4762         (the conclusion MUST be a formula variable)
  4763   + ignores types, which can make HOL proofs fail
  4764   + rules must not require higher-order unification, e.g. apply_type in ZF
  4765     [message "Function Var's argument not a bound variable" relates to this]
  4766   + its proof strategy is more general but can actually be slower
  4767 
  4768 * substitution with equality assumptions no longer permutes other
  4769 assumptions;
  4770 
  4771 * minor changes in semantics of addafter (now called addaltern); renamed
  4772 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4773 (and access functions for it);
  4774 
  4775 * improved combination of classical reasoner and simplifier:
  4776   + functions for handling clasimpsets
  4777   + improvement of addss: now the simplifier is called _after_ the
  4778     safe steps.
  4779   + safe variant of addss called addSss: uses safe simplifications
  4780     _during_ the safe steps. It is more complete as it allows multiple
  4781     instantiations of unknowns (e.g. with slow_tac).
  4782 
  4783 *** Simplifier ***
  4784 
  4785 * added interface for simplification procedures (functions that
  4786 produce *proven* rewrite rules on the fly, depending on current
  4787 redex);
  4788 
  4789 * ordering on terms as parameter (used for ordered rewriting);
  4790 
  4791 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4792 
  4793 * the solver is now split into a safe and an unsafe part.
  4794 This should be invisible for the normal user, except that the
  4795 functions setsolver and addsolver have been renamed to setSolver and
  4796 addSolver; added safe_asm_full_simp_tac;
  4797 
  4798 
  4799 *** HOL ***
  4800 
  4801 * a generic induction tactic `induct_tac' which works for all datatypes and
  4802 also for type `nat';
  4803 
  4804 * a generic case distinction tactic `exhaust_tac' which works for all
  4805 datatypes and also for type `nat';
  4806 
  4807 * each datatype comes with a function `size';
  4808 
  4809 * patterns in case expressions allow tuple patterns as arguments to
  4810 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4811 
  4812 * primrec now also works with type nat;
  4813 
  4814 * recdef: a new declaration form, allows general recursive functions to be
  4815 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4816 
  4817 * the constant for negation has been renamed from "not" to "Not" to
  4818 harmonize with FOL, ZF, LK, etc.;
  4819 
  4820 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4821 infinite lists;
  4822 
  4823 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4824 
  4825 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4826 problems in commutative rings, using axiomatic type classes for + and *;
  4827 
  4828 * more examples in HOL/MiniML and HOL/Auth;
  4829 
  4830 * more default rewrite rules for quantifiers, union/intersection;
  4831 
  4832 * a new constant `arbitrary == @x.False';
  4833 
  4834 * HOLCF/IOA replaces old HOL/IOA;
  4835 
  4836 * HOLCF changes: derived all rules and arities
  4837   + axiomatic type classes instead of classes
  4838   + typedef instead of faking type definitions
  4839   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4840   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4841   + eliminated the types void, one, tr
  4842   + use unit lift and bool lift (with translations) instead of one and tr
  4843   + eliminated blift from Lift3.thy (use Def instead of blift)
  4844   all eliminated rules are derived as theorems --> no visible changes ;
  4845 
  4846 
  4847 *** ZF ***
  4848 
  4849 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4850 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4851 as ZF_cs addSIs [equalityI];
  4852 
  4853 
  4854 
  4855 New in Isabelle94-7 (November 96)
  4856 ---------------------------------
  4857 
  4858 * allowing negative levels (as offsets) in prlev and choplev;
  4859 
  4860 * super-linear speedup for large simplifications;
  4861 
  4862 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4863 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4864 FAIL); can suppress it using the command Delsimps (ex_simps @
  4865 all_simps); De Morgan laws are also now included, by default;
  4866 
  4867 * improved printing of ==>  :  ~:
  4868 
  4869 * new object-logic "Sequents" adds linear logic, while replacing LK
  4870 and Modal (thanks to Sara Kalvala);
  4871 
  4872 * HOL/Auth: correctness proofs for authentication protocols;
  4873 
  4874 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4875 examples on HOL/Auth);
  4876 
  4877 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4878 the rewriter and classical reasoner simultaneously;
  4879 
  4880 * function uresult no longer returns theorems in "standard" format;
  4881 regain previous version by: val uresult = standard o uresult;
  4882 
  4883 
  4884 
  4885 New in Isabelle94-6
  4886 -------------------
  4887 
  4888 * oracles -- these establish an interface between Isabelle and trusted
  4889 external reasoners, which may deliver results as theorems;
  4890 
  4891 * proof objects (in particular record all uses of oracles);
  4892 
  4893 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4894 
  4895 * "constdefs" section in theory files;
  4896 
  4897 * "primrec" section (HOL) no longer requires names;
  4898 
  4899 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4900 
  4901 
  4902 
  4903 New in Isabelle94-5
  4904 -------------------
  4905 
  4906 * reduced space requirements;
  4907 
  4908 * automatic HTML generation from theories;
  4909 
  4910 * theory files no longer require "..." (quotes) around most types;
  4911 
  4912 * new examples, including two proofs of the Church-Rosser theorem;
  4913 
  4914 * non-curried (1994) version of HOL is no longer distributed;
  4915 
  4916 
  4917 
  4918 New in Isabelle94-4
  4919 -------------------
  4920 
  4921 * greatly reduced space requirements;
  4922 
  4923 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4924 
  4925 * searchable theorem database (see the section "Retrieving theorems" on
  4926 page 8 of the Reference Manual);
  4927 
  4928 * new examples, including Grabczewski's monumental case study of the
  4929 Axiom of Choice;
  4930 
  4931 * The previous version of HOL renamed to Old_HOL;
  4932 
  4933 * The new version of HOL (previously called CHOL) uses a curried syntax
  4934 for functions.  Application looks like f a b instead of f(a,b);
  4935 
  4936 * Mutually recursive inductive definitions finally work in HOL;
  4937 
  4938 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4939 translates to the operator "split";
  4940 
  4941 
  4942 
  4943 New in Isabelle94-3
  4944 -------------------
  4945 
  4946 * new infix operator, addss, allowing the classical reasoner to
  4947 perform simplification at each step of its search.  Example:
  4948         fast_tac (cs addss ss)
  4949 
  4950 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4951 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4952 look like (a,b) instead of <a,b>;
  4953 
  4954 * PLEASE NOTE: CHOL will eventually replace HOL!
  4955 
  4956 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4957 It translates to the operator "split".  A new theory of integers is available;
  4958 
  4959 * In ZF, integer numerals now denote two's-complement binary integers.
  4960 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4961 
  4962 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4963 of the Axiom of Choice;
  4964 
  4965 
  4966 
  4967 New in Isabelle94-2
  4968 -------------------
  4969 
  4970 * Significantly faster resolution;
  4971 
  4972 * the different sections in a .thy file can now be mixed and repeated
  4973 freely;
  4974 
  4975 * Database of theorems for FOL, HOL and ZF.  New
  4976 commands including qed, qed_goal and bind_thm store theorems in the database.
  4977 
  4978 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4979 a given theory (thms_of), or find out what theory a theorem was proved in
  4980 (theory_of_thm);
  4981 
  4982 * Bugs fixed in the inductive definition and datatype packages;
  4983 
  4984 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4985 and HOL_dup_cs obsolete;
  4986 
  4987 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4988 have been removed;
  4989 
  4990 * Simpler definition of function space in ZF;
  4991 
  4992 * new results about cardinal and ordinal arithmetic in ZF;
  4993 
  4994 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4995 types;
  4996 
  4997 :mode=text:wrap=hard:maxLineLen=72:
  4998 $Id$