NEWS
author wenzelm
Thu Oct 04 14:42:11 2007 +0200 (2007-10-04)
changeset 24829 e1214fa781ca
parent 24804 513bb015b469
child 24859 9b9b1599fb89
permissions -rw-r--r--
avoid gensym;
     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 * New "auto_quickcheck" feature tests outermost goal statements for
   533 potential counter-examples.  Controlled by ML references
   534 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   535 5000 milliseconds).
   536 
   537 * Internal reorganisation of `size' of datatypes: size theorems
   538 "foo.size" are no longer subsumed by "foo.simps" (but are still
   539 simplification rules by default!); theorems "prod.size" now named
   540 "*.size"
   541 
   542 * The transitivity reasoner for partial and linear orders is set up
   543 for locales "order" and "linorder" generated by the new class package
   544 (instead of axiomatic type classes used before).  Instances of the
   545 reasoner are available in all contexts importing or interpreting these
   546 locales.  Method "order" invokes the reasoner separately; the reasoner
   547 is also integrated with the Simplifier as a solver.  Diagnostic
   548 command 'print_orders' shows the available instances of the reasoner
   549 in the current context.
   550 
   551 * Formulation of theorem "dense" changed slightly due to integration
   552 with new class dense_linear_order.
   553 
   554 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   555 Linorder etc.  have disappeared; operations defined in terms of
   556 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   557 
   558 * HOL-Word: New extensive library and type for generic, fixed size
   559 machine words, with arithemtic, bit-wise, shifting and rotating
   560 operations, reflection into int, nat, and bool lists, automation for
   561 linear arithmetic (by automatic reflection into nat or int), including
   562 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   563 arithmetic type classes, supporting automatic simplification of
   564 numerals on all operations.
   565 
   566 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   567 
   568 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   569 
   570 * Code generator library theories:
   571   - Pretty_Int represents HOL integers by big integer literals in target
   572     languages.
   573   - Pretty_Char represents HOL characters by character literals in target
   574     languages.
   575   - Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   576     codes; includes Pretty_Int.
   577   - Executable_Set allows to generate code for finite sets using lists.
   578   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   579     denominator).
   580   - Executable_Real implements a subset of real numbers, namly those
   581     representable by rational numbers.
   582   - Efficient_Nat implements natural numbers by integers, which in general will
   583     result in higher efficency; pattern matching with 0/Suc is eliminated;
   584     includes Pretty_Int.
   585   - ML_String provides an additional datatype ml_string; in the HOL default
   586     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   587     of type ml_string are mapped to strings in SML.
   588   - ML_Int provides an additional datatype ml_int which is mapped to to SML
   589     built-in integers.
   590 
   591 * New package for inductive predicates
   592 
   593   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   594 
   595     inductive
   596       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   597       for z_1 :: U_1 and ... and z_n :: U_m
   598     where
   599       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   600     | ...
   601 
   602   with full support for type-inference, rather than
   603 
   604     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   605 
   606     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   607     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   608 
   609     inductive "s z_1 ... z_m"
   610     intros
   611       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   612       ...
   613 
   614   For backward compatibility, there is a wrapper allowing inductive
   615   sets to be defined with the new package via
   616 
   617     inductive_set
   618       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   619       for z_1 :: U_1 and ... and z_n :: U_m
   620     where
   621       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   622     | ...
   623 
   624   or
   625 
   626     inductive_set
   627       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   628       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   629       for z_1 :: U_1 and ... and z_n :: U_m
   630     where
   631       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   632     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   633     | ...
   634 
   635   if the additional syntax "p ..." is required.
   636 
   637   Numerous examples can be found in the subdirectories HOL/Auth, HOL/Bali,
   638   HOL/Induct, and HOL/MicroJava.
   639 
   640   INCOMPATIBILITIES:
   641 
   642   - Since declaration and definition of inductive sets or predicates
   643     is no longer separated, abbreviations involving the newly
   644     introduced sets or predicates must be specified together with the
   645     introduction rules after the 'where' keyword (see above), rather
   646     than before the actual inductive definition.
   647 
   648   - The variables in induction and elimination rules are now
   649     quantified in the order of their occurrence in the introduction
   650     rules, rather than in alphabetical order. Since this may break
   651     some proofs, these proofs either have to be repaired, e.g. by
   652     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
   653     statements of the form
   654 
   655       case (rule_i a_i_1 ... a_i_{k_i})
   656 
   657     or the old order of quantification has to be restored by explicitly adding
   658     meta-level quantifiers in the introduction rules, i.e.
   659 
   660       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   661 
   662   - The format of the elimination rules is now
   663 
   664       p z_1 ... z_m x_1 ... x_n ==>
   665         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   666         ==> ... ==> P
   667 
   668     for predicates and
   669 
   670       (x_1, ..., x_n) : s z_1 ... z_m ==>
   671         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   672         ==> ... ==> P
   673 
   674     for sets rather than
   675 
   676       x : s z_1 ... z_m ==>
   677         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   678         ==> ... ==> P
   679 
   680     This may require terms in goals to be expanded to n-tuples
   681     (e.g. using case_tac or simplification with the split_paired_all
   682     rule) before the above elimination rule is applicable.
   683 
   684   - The elimination or case analysis rules for (mutually) inductive
   685     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
   686     list of rules "p_1_..._p_k.elims" is no longer available.
   687 
   688 * Method "metis" proves goals by applying the Metis general-purpose
   689 resolution prover.  Examples are in the directory MetisExamples.  See
   690 also http://gilith.com/software/metis/
   691 
   692 WARNING: the Isabelle/HOL-Metis integration does not yet work properly
   693 with multi-threading.
   694   
   695 * Command 'sledgehammer' invokes external automatic theorem provers as
   696 background processes.  It generates calls to the "metis" method if
   697 successful. These can be pasted into the proof.  Users do not have to
   698 wait for the automatic provers to return.
   699 
   700 * Case-expressions allow arbitrary constructor-patterns (including
   701 "_") and take their order into account, like in functional
   702 programming.  Internally, this is translated into nested
   703 case-expressions; missing cases are added and mapped to the predefined
   704 constant "undefined". In complicated cases printing may no longer show
   705 the original input but the internal form. Lambda-abstractions allow
   706 the same form of pattern matching: "% pat1 => e1 | ..." is an
   707 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
   708 variable.
   709 
   710 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   711 is an abbreviation for "of_nat :: nat => int". The simplification
   712 rules for "of_nat" have been changed to work like "int" did
   713 previously.  Potential INCOMPATIBILITY:
   714   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   715   - of_nat_diff and of_nat_mult are no longer default simp rules
   716 
   717 * Method "algebra" solves polynomial equations over (semi)rings using
   718 Groebner bases. The (semi)ring structure is defined by locales and the
   719 tool setup depends on that generic context. Installing the method for
   720 a specific type involves instantiating the locale and possibly adding
   721 declarations for computation on the coefficients.  The method is
   722 already instantiated for natural numbers and for the axiomatic class
   723 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
   724 CALCULEMUS 2007 for the general principles underlying this
   725 architecture of context-aware proof-tools.
   726 
   727 * Former constant "List.op @" now named "List.append".  Use ML
   728 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
   729 circumvent possible incompatibilities when working on ML level.
   730 
   731 * Some renaming of class constants due to canonical name prefixing in
   732 the new 'class' package:
   733 
   734     HOL.abs ~> HOL.minus_class.abs
   735     HOL.divide ~> HOL.divide_class.divide
   736     Nat.power ~> Nat.power_class.power
   737     Nat.size ~> Nat.size_class.size
   738     Numeral.number_of ~> Numeral.number_class.number_of
   739     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   740     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   741     Orderings.min ~> Orderings.ord_class.min
   742     Orderings.max ~> Orderings.ord_class.max
   743 
   744 * New class "default" with associated constant "default".
   745 
   746 * New constant "undefined" with axiom "undefined x = undefined".
   747 
   748 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   749 
   750 * New function listsum :: 'a list => 'a for arbitrary monoids.
   751 Special syntax: "SUM x <- xs. f x" (and latex variants)
   752 
   753 * New syntax for Haskell-like list comprehension (input only), eg.
   754 [(x,y). x <- xs, y <- ys, x ~= y], see also HOL/List.thy.
   755 
   756 * The special syntax for function "filter" has changed from [x :
   757 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
   758 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
   759 
   760 * [a..b] is now defined for arbitrary linear orders.  It used to be
   761 defined on nat only, as an abbreviation for [a..<Suc b]
   762 INCOMPATIBILITY.
   763 
   764 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
   765 
   766 * New functions "sorted" and "sort" in HOL/List.thy.
   767 
   768 * Function "sgn" is now overloaded and available on int, real, complex
   769 (and other numeric types), using class "sgn".  Two possible defs of
   770 sgn are given as equational assumptions in the classes sgn_if and
   771 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   772 INCOMPATIBILITY.
   773 
   774 * New lemma collection field_simps (an extension of ring_simps) for
   775 manipulating (in)equations involving division. Multiplies with all
   776 denominators that can be proved to be non-zero (in equations) or
   777 positive/negative (in inequations).
   778 
   779 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   780 have been improved and renamed to ring_simps, group_simps and
   781 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
   782 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
   783 
   784 * Library/Pretty_Int.thy: maps HOL numerals on target language integer
   785 literals when generating code.
   786 
   787 * Library/Pretty_Char.thy: maps HOL characters on target language
   788 character literals when generating code.
   789 
   790 * Library/Commutative_Ring.thy: switched from recdef to function
   791 package; constants add, mul, pow now curried.  Infix syntax for
   792 algebraic operations.
   793 
   794 * Some steps towards more uniform lattice theory development in HOL.
   795 
   796     constants "meet" and "join" now named "inf" and "sup"
   797     constant "Meet" now named "Inf"
   798 
   799     classes "meet_semilorder" and "join_semilorder" now named
   800       "lower_semilattice" and "upper_semilattice"
   801     class "lorder" now named "lattice"
   802     class "comp_lat" now named "complete_lattice"
   803 
   804     Instantiation of lattice classes allows explicit definitions
   805     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   806 
   807   INCOMPATIBILITY.  Theorem renames:
   808 
   809     meet_left_le            ~> inf_le1
   810     meet_right_le           ~> inf_le2
   811     join_left_le            ~> sup_ge1
   812     join_right_le           ~> sup_ge2
   813     meet_join_le            ~> inf_sup_ord
   814     le_meetI                ~> le_infI
   815     join_leI                ~> le_supI
   816     le_meet                 ~> le_inf_iff
   817     le_join                 ~> ge_sup_conv
   818     meet_idempotent         ~> inf_idem
   819     join_idempotent         ~> sup_idem
   820     meet_comm               ~> inf_commute
   821     join_comm               ~> sup_commute
   822     meet_leI1               ~> le_infI1
   823     meet_leI2               ~> le_infI2
   824     le_joinI1               ~> le_supI1
   825     le_joinI2               ~> le_supI2
   826     meet_assoc              ~> inf_assoc
   827     join_assoc              ~> sup_assoc
   828     meet_left_comm          ~> inf_left_commute
   829     meet_left_idempotent    ~> inf_left_idem
   830     join_left_comm          ~> sup_left_commute
   831     join_left_idempotent    ~> sup_left_idem
   832     meet_aci                ~> inf_aci
   833     join_aci                ~> sup_aci
   834     le_def_meet             ~> le_iff_inf
   835     le_def_join             ~> le_iff_sup
   836     join_absorp2            ~> sup_absorb2
   837     join_absorp1            ~> sup_absorb1
   838     meet_absorp1            ~> inf_absorb1
   839     meet_absorp2            ~> inf_absorb2
   840     meet_join_absorp        ~> inf_sup_absorb
   841     join_meet_absorp        ~> sup_inf_absorb
   842     distrib_join_le         ~> distrib_sup_le
   843     distrib_meet_le         ~> distrib_inf_le
   844 
   845     add_meet_distrib_left   ~> add_inf_distrib_left
   846     add_join_distrib_left   ~> add_sup_distrib_left
   847     is_join_neg_meet        ~> is_join_neg_inf
   848     is_meet_neg_join        ~> is_meet_neg_sup
   849     add_meet_distrib_right  ~> add_inf_distrib_right
   850     add_join_distrib_right  ~> add_sup_distrib_right
   851     add_meet_join_distribs  ~> add_sup_inf_distribs
   852     join_eq_neg_meet        ~> sup_eq_neg_inf
   853     meet_eq_neg_join        ~> inf_eq_neg_sup
   854     add_eq_meet_join        ~> add_eq_inf_sup
   855     meet_0_imp_0            ~> inf_0_imp_0
   856     join_0_imp_0            ~> sup_0_imp_0
   857     meet_0_eq_0             ~> inf_0_eq_0
   858     join_0_eq_0             ~> sup_0_eq_0
   859     neg_meet_eq_join        ~> neg_inf_eq_sup
   860     neg_join_eq_meet        ~> neg_sup_eq_inf
   861     join_eq_if              ~> sup_eq_if
   862 
   863     mono_meet               ~> mono_inf
   864     mono_join               ~> mono_sup
   865     meet_bool_eq            ~> inf_bool_eq
   866     join_bool_eq            ~> sup_bool_eq
   867     meet_fun_eq             ~> inf_fun_eq
   868     join_fun_eq             ~> sup_fun_eq
   869     meet_set_eq             ~> inf_set_eq
   870     join_set_eq             ~> sup_set_eq
   871     meet1_iff               ~> inf1_iff
   872     meet2_iff               ~> inf2_iff
   873     meet1I                  ~> inf1I
   874     meet2I                  ~> inf2I
   875     meet1D1                 ~> inf1D1
   876     meet2D1                 ~> inf2D1
   877     meet1D2                 ~> inf1D2
   878     meet2D2                 ~> inf2D2
   879     meet1E                  ~> inf1E
   880     meet2E                  ~> inf2E
   881     join1_iff               ~> sup1_iff
   882     join2_iff               ~> sup2_iff
   883     join1I1                 ~> sup1I1
   884     join2I1                 ~> sup2I1
   885     join1I1                 ~> sup1I1
   886     join2I2                 ~> sup1I2
   887     join1CI                 ~> sup1CI
   888     join2CI                 ~> sup2CI
   889     join1E                  ~> sup1E
   890     join2E                  ~> sup2E
   891 
   892     is_meet_Meet            ~> is_meet_Inf
   893     Meet_bool_def           ~> Inf_bool_def
   894     Meet_fun_def            ~> Inf_fun_def
   895     Meet_greatest           ~> Inf_greatest
   896     Meet_lower              ~> Inf_lower
   897     Meet_set_def            ~> Inf_set_def
   898 
   899     Sup_def                 ~> Sup_Inf
   900     Sup_bool_eq             ~> Sup_bool_def
   901     Sup_fun_eq              ~> Sup_fun_def
   902     Sup_set_eq              ~> Sup_set_def
   903 
   904     listsp_meetI            ~> listsp_infI
   905     listsp_meet_eq          ~> listsp_inf_eq
   906 
   907     meet_min                ~> inf_min
   908     join_max                ~> sup_max
   909 
   910 * Renamed classes "order" and "linorder": facts "refl", "trans" and
   911 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   912 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   913 
   914 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   915 changed order of proof goals instance proofs.
   916 
   917 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
   918 INCOMPATIBILITY.
   919 
   920 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
   921 INCOMPATIBILITY.
   922 
   923 * Added syntactic class "size"; overloaded constant "size" now has
   924 type "'a::size ==> bool"
   925 
   926 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   927 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and
   928 "Divides.dvd". INCOMPATIBILITY.
   929 
   930 * Method "lexicographic_order" automatically synthesizes termination
   931 relations as lexicographic combinations of size measures -- 'function'
   932 package.
   933 
   934 * HOL/records: generalised field-update to take a function on the
   935 field rather than the new value: r(|A := x|) is translated to A_update
   936 (K x) r The K-combinator that is internally used is called K_record.
   937 INCOMPATIBILITY: Usage of the plain update functions has to be
   938 adapted.
   939  
   940 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
   941 * x = 0, which are required for a semiring.  Richer structures do not
   942 inherit from semiring_0 anymore, because this property is a theorem
   943 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
   944 there is more to prove, but this is mostly trivial.
   945 
   946 * Class "recpower" is generalized to arbitrary monoids, not just
   947 commutative semirings.  INCOMPATIBILITY: may need to incorporate
   948 commutativity or a semiring properties additionally.
   949 
   950 * Unified locale "partial_order" with class definition (cf. theory
   951 Orderings), added parameter "less".  INCOMPATIBILITY.
   952 
   953 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   954 INCOMPATIBILITY: translations containing list_all2 may go wrong,
   955 better use 'abbreviation'.
   956 
   957 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
   958 
   959 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to
   960 "HOL.one_class.one".  INCOMPATIBILITY.
   961 
   962 * Added class "HOL.eq", allowing for code generation with polymorphic
   963 equality.
   964 
   965 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   966 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
   967 significant changes for setting up numeral syntax for types:
   968   - New constants Numeral.pred and Numeral.succ instead
   969       of former Numeral.bin_pred and Numeral.bin_succ.
   970   - Use integer operations instead of bin_add, bin_mult and so on.
   971   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   972   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   973 
   974 See HOL/Integ/IntArith.thy for an example setup.
   975 
   976 * New top level command 'normal_form' computes the normal form of a
   977 term that may contain free variables.  For example ``normal_form
   978 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   979 suitable for heavy-duty computations because the functions are
   980 compiled to ML first.
   981 
   982 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   983 25 like -->); output depends on the "iff" print_mode, the default is
   984 "A = B" (with priority 50).
   985 
   986 * Renamed constants in HOL.thy and Orderings.thy:
   987     op +   ~> HOL.plus_class.plus
   988     op -   ~> HOL.minus_class.minus
   989     uminus ~> HOL.minus_class.uminus
   990     abs    ~> HOL.abs_class.abs
   991     op *   ~> HOL.times_class.times
   992     op <   ~> HOL.ord_class.less
   993     op <=  ~> HOL.ord_class.less_eq
   994 
   995 Adaptions may be required in the following cases:
   996 
   997 a) User-defined constants using any of the names "plus", "minus",
   998 "times", "less" or "less_eq". The standard syntax translations for
   999 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1000 names.
  1001 
  1002 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1003 INCOMPATIBILITY: use more specific names.
  1004 
  1005 c) Permutative equations (e.g. "a + b = b + a")
  1006 Since the change of names also changes the order of terms, permutative
  1007 rewrite rules may get applied in a different order. Experience shows
  1008 that this is rarely the case (only two adaptions in the whole Isabelle
  1009 distribution).  INCOMPATIBILITY: rewrite proofs
  1010 
  1011 d) ML code directly refering to constant names
  1012 This in general only affects hand-written proof tactics, simprocs and
  1013 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1014 Consider using @{const_name} antiquotation.
  1015 
  1016 * Relations less (<) and less_eq (<=) are also available on type bool.
  1017 Modified syntax to disallow nesting without explicit parentheses,
  1018 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1019 INCOMPATIBILITY.
  1020 
  1021 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1022 
  1023 * Relation composition operator "op O" now has precedence 75 and binds
  1024 stronger than union and intersection. INCOMPATIBILITY.
  1025 
  1026 * The old set interval syntax "{m..n(}" (and relatives) has been
  1027 removed.  Use "{m..<n}" (and relatives) instead.
  1028 
  1029 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1030 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1031 ``declare [[simproc del: neq]]''.
  1032 
  1033 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1034 True/False.
  1035 
  1036 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1037 
  1038 * Theorem setsum_mult renamed to setsum_right_distrib.
  1039 
  1040 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1041 ``rule'' method.
  1042 
  1043 * Reimplemented methods "sat" and "satx", with several improvements:
  1044 goals no longer need to be stated as "<prems> ==> False", equivalences
  1045 (i.e. "=" on type bool) are handled, variable names of the form
  1046 "lit_<n>" are no longer reserved, significant speedup.
  1047 
  1048 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1049 zChaff is still supported as well.
  1050 
  1051 * 'inductive' and 'datatype': provide projections of mutual rules,
  1052 bundled as foo_bar.inducts;
  1053 
  1054 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1055 Library.
  1056 
  1057 * Library: moved theory Accessible_Part to main HOL.
  1058 
  1059 * Library: added theory Coinductive_List of potentially infinite lists
  1060 as greatest fixed-point.
  1061 
  1062 * Library: added theory AssocList which implements (finite) maps as
  1063 association lists.
  1064 
  1065 * Method "evaluation" solves goals (i.e. a boolean expression)
  1066 efficiently by compiling it to ML.  The goal is "proved" (via an
  1067 oracle) if it evaluates to True.
  1068 
  1069 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1070 also when invoked by the simplifier.  This results in the Simplifier
  1071 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1072 Configuration option fast_arith_split_limit=0 recovers the old
  1073 behavior.
  1074 
  1075 * Support for hex (0x20) and binary (0b1001) numerals.
  1076 
  1077 * New method: reify eqs (t), where eqs are equations for an
  1078 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1079 parameter, computes a term s::'b and a list xs::'a list and proves the
  1080 theorem I xs s = t. This is also known as reification or quoting. The
  1081 resulting theorem is applied to the subgoal to substitute t with I xs
  1082 s.  If t is omitted, the subgoal itself is reified.
  1083 
  1084 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1085 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1086 where f is supposed to be a computable function (in the sense of code
  1087 generattion). The method uses reify to compute s and xs as above then
  1088 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1089 r and finally gets the theorem t = r, which is again applied to the
  1090 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1091 
  1092 * Reflection: Automatic reification now handels binding, an example
  1093 is available in HOL/ex/ReflectionEx.thy
  1094 
  1095 
  1096 *** HOL-Complex ***
  1097 
  1098 * Hyperreal: Functions root and sqrt are now defined on negative real
  1099 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1100 Nonnegativity side conditions have been removed from many lemmas, so
  1101 that more subgoals may now be solved by simplification; potential
  1102 INCOMPATIBILITY.
  1103 
  1104 * Real: new type classes formalize real normed vector spaces and
  1105 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1106 and norm :: 'a => real.
  1107 
  1108 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1109 reals into other types. The overloaded constant Reals :: 'a set is now
  1110 defined as range of_real; potential INCOMPATIBILITY.
  1111 
  1112 * Real: proper support for ML code generation, including 'quickcheck'.
  1113 Reals are implemented as arbitrary precision rationals.
  1114 
  1115 * Hyperreal: Several constants that previously worked only for the
  1116 reals have been generalized, so they now work over arbitrary vector
  1117 spaces. Type annotations may need to be added in some cases; potential
  1118 INCOMPATIBILITY.
  1119 
  1120   Infinitesimal  :: ('a::real_normed_vector) star set
  1121   HFinite        :: ('a::real_normed_vector) star set
  1122   HInfinite      :: ('a::real_normed_vector) star set
  1123   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1124   monad          :: ('a::real_normed_vector) star => 'a star set
  1125   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1126   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1127   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1128   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1129   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1130   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1131   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1132   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1133   sgn            :: 'a::real_normed_vector => 'a
  1134   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1135 
  1136 * Complex: Some complex-specific constants are now abbreviations for
  1137 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1138 hnorm.  Other constants have been entirely removed in favor of the
  1139 polymorphic versions (INCOMPATIBILITY):
  1140 
  1141   approx        <-- capprox
  1142   HFinite       <-- CFinite
  1143   HInfinite     <-- CInfinite
  1144   Infinitesimal <-- CInfinitesimal
  1145   monad         <-- cmonad
  1146   galaxy        <-- cgalaxy
  1147   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1148   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1149   (ns)deriv     <-- (ns)cderiv
  1150 
  1151 
  1152 *** HOL-Algebra ***
  1153 
  1154 * Formalisation of ideals and the quotient construction over rings.
  1155 
  1156 * Order and lattice theory no longer based on records.
  1157 INCOMPATIBILITY.
  1158 
  1159 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1160 greatest_closed.  INCOMPATIBILITY.
  1161 
  1162 * Method algebra is now set up via an attribute.  For examples see
  1163 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1164 of algebraic structures.
  1165 
  1166 * Renamed theory CRing to Ring.
  1167 
  1168 
  1169 *** HOL-Nominal ***
  1170 
  1171 * Fully featured support for nominal datatypes (binding structures)
  1172 due to the HOL-Nominal logic.  See HOL/Nominal, HOL/Nominal/Examples,
  1173 and http://isabelle.in.tum.de/nominal/download.html
  1174 
  1175 
  1176 *** ML ***
  1177 
  1178 * ML basics: just one true type int, which coincides with IntInf.int
  1179 (even on SML/NJ).
  1180 
  1181 * ML within Isar: antiquotations allow to embed statically-checked
  1182 formal entities in the source, referring to the context available at
  1183 compile-time.  For example:
  1184 
  1185 ML {* @{typ "'a => 'b"} *}
  1186 ML {* @{term "%x. x"} *}
  1187 ML {* @{prop "x == y"} *}
  1188 ML {* @{ctyp "'a => 'b"} *}
  1189 ML {* @{cterm "%x. x"} *}
  1190 ML {* @{cprop "x == y"} *}
  1191 ML {* @{thm asm_rl} *}
  1192 ML {* @{thms asm_rl} *}
  1193 ML {* @{type_name c} *}
  1194 ML {* @{const_name c} *}
  1195 ML {* @{const_syntax c} *}
  1196 ML {* @{context} *}
  1197 ML {* @{theory} *}
  1198 ML {* @{theory Pure} *}
  1199 ML {* @{theory_ref} *}
  1200 ML {* @{theory_ref Pure} *}
  1201 ML {* @{simpset} *}
  1202 ML {* @{claset} *}
  1203 ML {* @{clasimpset} *}
  1204 
  1205 The same works for sources being ``used'' within an Isar context.
  1206 
  1207 * ML in Isar: improved error reporting; extra verbosity with
  1208 ML_Context.trace enabled.
  1209 
  1210 * Pure/General/table.ML: the join operations now works via exceptions
  1211 DUP/SAME instead of type option. This is simpler in simple cases, and
  1212 admits slightly more efficient complex applications.
  1213 
  1214 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1215 use Context.generic instead of just theory.
  1216 
  1217 * Pure: datatype Context.generic joins theory/Proof.context and
  1218 provides some facilities for code that works in either kind of
  1219 context, notably GenericDataFun for uniform theory and proof data.
  1220 
  1221 * Pure: simplified internal attribute type, which is now always
  1222 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1223 local (Proof.context) attributes have been discontinued, while
  1224 minimizing code duplication. Thm.rule_attribute and
  1225 Thm.declaration_attribute build canonical attributes; see also structure
  1226 Context for further operations on Context.generic, notably
  1227 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1228 declarations and definitions.
  1229 
  1230 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1231 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1232 init only required for impure data. INCOMPATIBILITY: empty really need
  1233 to be empty (no dependencies on theory content!)
  1234 
  1235 * Pure/kernel: consts certification ignores sort constraints given in
  1236 signature declarations. (This information is not relevant to the
  1237 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1238 potential INCOMPATIBILITY.
  1239 
  1240 * Pure: axiomatic type classes are now purely definitional, with
  1241 explicit proofs of class axioms and super class relations performed
  1242 internally. See Pure/axclass.ML for the main internal interfaces --
  1243 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1244 AxClass.axiomatize_class/classrel/arity supersede
  1245 Sign.add_classes/classrel/arities.
  1246 
  1247 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1248 global/local versions on theory vs. Proof.context have been
  1249 discontinued; Attrib.syntax and Method.syntax have been adapted
  1250 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1251 attributes, methods, etc.
  1252 
  1253 * Pure: several functions of signature "... -> theory -> theory * ..."
  1254 have been reoriented to "... -> theory -> ... * theory" in order to
  1255 allow natural usage in combination with the ||>, ||>>, |-> and
  1256 fold_map combinators.
  1257 
  1258 * Pure: official theorem names (closed derivations) and additional
  1259 comments (tags) are now strictly separate.  Name hints -- which are
  1260 maintained as tags -- may be attached any time without affecting the
  1261 derivation.
  1262 
  1263 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1264 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1265 achieve the old behaviour.
  1266 
  1267 * Pure: the "Goal" constant is now called "prop", supporting a
  1268 slightly more general idea of ``protecting'' meta-level rule
  1269 statements.
  1270 
  1271 * Pure: Logic.(un)varify only works in a global context, which is now
  1272 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1273 Logic.legacy_(un)varify as temporary workaround.
  1274 
  1275 * Pure: structure Name provides scalable operations for generating
  1276 internal variable names, notably Name.variants etc.  This replaces
  1277 some popular functions from term.ML:
  1278 
  1279   Term.variant		->  Name.variant
  1280   Term.variantlist	->  Name.variant_list
  1281   Term.invent_names	->  Name.invent_list
  1282 
  1283 Note that low-level renaming rarely occurs in new code -- operations
  1284 from structure Variable are used instead (see below).
  1285 
  1286 * Pure: structure Variable provides fundamental operations for proper
  1287 treatment of fixed/schematic variables in a context.  For example,
  1288 Variable.import introduces fixes for schematics of given facts and
  1289 Variable.export reverses the effect (up to renaming) -- this replaces
  1290 various freeze_thaw operations.
  1291 
  1292 * Pure: structure Goal provides simple interfaces for
  1293 init/conclude/finish and tactical prove operations (replacing former
  1294 Tactic.prove).  Goal.prove is the canonical way to prove results
  1295 within a given context; Goal.prove_global is a degraded version for
  1296 theory level goals, including a global Drule.standard.  Note that
  1297 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1298 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1299 in a locale context).
  1300 
  1301 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1302 and type checking (Syntax.check_term etc.), with common combinations
  1303 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1304 which are considered legacy and await removal.
  1305 
  1306 * Isar: simplified treatment of user-level errors, using exception
  1307 ERROR of string uniformly.  Function error now merely raises ERROR,
  1308 without any side effect on output channels.  The Isar toplevel takes
  1309 care of proper display of ERROR exceptions.  ML code may use plain
  1310 handle/can/try; cat_error may be used to concatenate errors like this:
  1311 
  1312   ... handle ERROR msg => cat_error msg "..."
  1313 
  1314 Toplevel ML code (run directly or through the Isar toplevel) may be
  1315 embedded into the Isar toplevel with exception display/debug like
  1316 this:
  1317 
  1318   Isar.toplevel (fn () => ...)
  1319 
  1320 INCOMPATIBILITY, removed special transform_error facilities, removed
  1321 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1322 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1323 -- use plain ERROR instead.
  1324 
  1325 * Isar: theory setup now has type (theory -> theory), instead of a
  1326 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1327 
  1328 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1329 ProofContext.debug/verbose flags.
  1330 
  1331 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1332 theory before entering a proof state.  Transactions now always see a
  1333 quasi-functional intermediate checkpoint, both in interactive and
  1334 batch mode.
  1335 
  1336 * Simplifier: the simpset of a running simplification process now
  1337 contains a proof context (cf. Simplifier.the_context), which is the
  1338 very context that the initial simpset has been retrieved from (by
  1339 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1340 (solver, looper etc.) may depend on arbitrary proof data.
  1341 
  1342 * Simplifier.inherit_context inherits the proof context (plus the
  1343 local bounds) of the current simplification process; any simproc
  1344 etc. that calls the Simplifier recursively should do this!  Removed
  1345 former Simplifier.inherit_bounds, which is already included here --
  1346 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1347 specify an explicit context using Simplifier.context/theory_context.
  1348 
  1349 * Simplifier/Classical Reasoner: more abstract interfaces
  1350 change_simpset/claset for modifying the simpset/claset reference of a
  1351 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1352 INCOMPATIBILITY.
  1353 
  1354 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1355 "Trueprop" etc.
  1356 
  1357 
  1358 *** System ***
  1359 
  1360 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1361 locations -- now includes the Isabelle version identifier as well.
  1362 This simplifies use of multiple Isabelle installations.
  1363 
  1364 * isabelle-process: option -S (secure mode) disables some critical
  1365 operations, notably runtime compilation and evaluation of ML source
  1366 code.
  1367 
  1368 * Support for parallel execution, using native multicore support of
  1369 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1370 independent theories, according to the given theory header
  1371 specifications. The maximum number of worker threads is specified via
  1372 usedir option -M or the "max-threads" setting in Proof General. A
  1373 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1374 to 6 on a 8-core machine.  User-code needs to observe certain
  1375 guidelines for thread-safe programming, see appendix A in the Isar
  1376 Implementation manual.
  1377 
  1378 
  1379 New in Isabelle2005 (October 2005)
  1380 ----------------------------------
  1381 
  1382 *** General ***
  1383 
  1384 * Theory headers: the new header syntax for Isar theories is
  1385 
  1386   theory <name>
  1387   imports <theory1> ... <theoryN>
  1388   uses <file1> ... <fileM>
  1389   begin
  1390 
  1391 where the 'uses' part is optional.  The previous syntax
  1392 
  1393   theory <name> = <theory1> + ... + <theoryN>:
  1394 
  1395 will disappear in the next release.  Use isatool fixheaders to convert
  1396 existing theory files.  Note that there is no change in ancient
  1397 non-Isar theories now, but these will disappear soon.
  1398 
  1399 * Theory loader: parent theories can now also be referred to via
  1400 relative and absolute paths.
  1401 
  1402 * Command 'find_theorems' searches for a list of criteria instead of a
  1403 list of constants. Known criteria are: intro, elim, dest, name:string,
  1404 simp:term, and any term. Criteria can be preceded by '-' to select
  1405 theorems that do not match. Intro, elim, dest select theorems that
  1406 match the current goal, name:s selects theorems whose fully qualified
  1407 name contain s, and simp:term selects all simplification rules whose
  1408 lhs match term.  Any other term is interpreted as pattern and selects
  1409 all theorems matching the pattern. Available in ProofGeneral under
  1410 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1411 
  1412   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1413 
  1414 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1415 matching the current goal as introduction rule and not having "HOL."
  1416 in their name (i.e. not being defined in theory HOL).
  1417 
  1418 * Command 'thms_containing' has been discontinued in favour of
  1419 'find_theorems'; INCOMPATIBILITY.
  1420 
  1421 * Communication with Proof General is now 8bit clean, which means that
  1422 Unicode text in UTF-8 encoding may be used within theory texts (both
  1423 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1424 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1425 
  1426   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1427   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1428 
  1429 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1430 Classical Reasoner.  Typical big applications run around 2 times
  1431 faster.
  1432 
  1433 
  1434 *** Document preparation ***
  1435 
  1436 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1437 of raw sources.  Only those symbols that do not require additional
  1438 LaTeX packages (depending on comments in isabellesym.sty) are
  1439 displayed properly, everything else is left verbatim.  isatool display
  1440 and isatool print are used as front ends (these are subject to the
  1441 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1442 
  1443 * Command tags control specific markup of certain regions of text,
  1444 notably folding and hiding.  Predefined tags include "theory" (for
  1445 theory begin and end), "proof" for proof commands, and "ML" for
  1446 commands involving ML code; the additional tags "visible" and
  1447 "invisible" are unused by default.  Users may give explicit tag
  1448 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1449 interpretation of tags is determined by the LaTeX job during document
  1450 preparation: see option -V of isatool usedir, or options -n and -t of
  1451 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1452 \isadroptag.
  1453 
  1454 Several document versions may be produced at the same time via isatool
  1455 usedir (the generated index.html will link all of them).  Typical
  1456 specifications include ''-V document=theory,proof,ML'' to present
  1457 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1458 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1459 these parts without any formal replacement text.  The Isabelle site
  1460 default settings produce ''document'' and ''outline'' versions as
  1461 specified above.
  1462 
  1463 * Several new antiquotations:
  1464 
  1465   @{term_type term} prints a term with its type annotated;
  1466 
  1467   @{typeof term} prints the type of a term;
  1468 
  1469   @{const const} is the same as @{term const}, but checks that the
  1470   argument is a known logical constant;
  1471 
  1472   @{term_style style term} and @{thm_style style thm} print a term or
  1473   theorem applying a "style" to it
  1474 
  1475   @{ML text}
  1476 
  1477 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1478 definitions, equations, inequations etc., 'concl' printing only the
  1479 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1480 to print the specified premise.  TermStyle.add_style provides an ML
  1481 interface for introducing further styles.  See also the "LaTeX Sugar"
  1482 document practical applications.  The ML antiquotation prints
  1483 type-checked ML expressions verbatim.
  1484 
  1485 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1486 and 'text' support optional locale specification '(in loc)', which
  1487 specifies the default context for interpreting antiquotations.  For
  1488 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1489 
  1490 * Option 'locale=NAME' of antiquotations specifies an alternative
  1491 context interpreting the subsequent argument.  For example: @{thm
  1492 [locale=lattice] inf_assoc}.
  1493 
  1494 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1495 a proof context.
  1496 
  1497 * Proper output of antiquotations for theory commands involving a
  1498 proof context (such as 'locale' or 'theorem (in loc) ...').
  1499 
  1500 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1501 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1502 
  1503 * isatool usedir: new option -C (default true) controls whether option
  1504 -D should include a copy of the original document directory; -C false
  1505 prevents unwanted effects such as copying of administrative CVS data.
  1506 
  1507 
  1508 *** Pure ***
  1509 
  1510 * Considerably improved version of 'constdefs' command.  Now performs
  1511 automatic type-inference of declared constants; additional support for
  1512 local structure declarations (cf. locales and HOL records), see also
  1513 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1514 sequential dependencies of definitions within a single 'constdefs'
  1515 section; moreover, the declared name needs to be an identifier.  If
  1516 all fails, consider to fall back on 'consts' and 'defs' separately.
  1517 
  1518 * Improved indexed syntax and implicit structures.  First of all,
  1519 indexed syntax provides a notational device for subscripted
  1520 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1521 expressions.  Secondly, in a local context with structure
  1522 declarations, number indexes \<^sub>n or the empty index (default
  1523 number 1) refer to a certain fixed variable implicitly; option
  1524 show_structs controls printing of implicit structures.  Typical
  1525 applications of these concepts involve record types and locales.
  1526 
  1527 * New command 'no_syntax' removes grammar declarations (and
  1528 translations) resulting from the given syntax specification, which is
  1529 interpreted in the same manner as for the 'syntax' command.
  1530 
  1531 * 'Advanced' translation functions (parse_translation etc.) may depend
  1532 on the signature of the theory context being presently used for
  1533 parsing/printing, see also isar-ref manual.
  1534 
  1535 * Improved 'oracle' command provides a type-safe interface to turn an
  1536 ML expression of type theory -> T -> term into a primitive rule of
  1537 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1538 is already included here); see also FOL/ex/IffExample.thy;
  1539 INCOMPATIBILITY.
  1540 
  1541 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1542 before); "cI" is no longer bound, use "c.intro" instead.
  1543 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1544 axclasses vs. locales.
  1545 
  1546 * Improved internal renaming of symbolic identifiers -- attach primes
  1547 instead of base 26 numbers.
  1548 
  1549 * New flag show_question_marks controls printing of leading question
  1550 marks in schematic variable names.
  1551 
  1552 * In schematic variable names, *any* symbol following \<^isub> or
  1553 \<^isup> is now treated as part of the base name.  For example, the
  1554 following works without printing of awkward ".0" indexes:
  1555 
  1556   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1557     by simp
  1558 
  1559 * Inner syntax includes (*(*nested*) comments*).
  1560 
  1561 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1562 annotations as "(00...)".
  1563 
  1564 * Clear separation of logical types and nonterminals, where the latter
  1565 may only occur in 'syntax' specifications or type abbreviations.
  1566 Before that distinction was only partially implemented via type class
  1567 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1568 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1569 exotic syntax specifications may require further adaption
  1570 (e.g. Cube/Cube.thy).
  1571 
  1572 * Removed obsolete type class "logic", use the top sort {} instead.
  1573 Note that non-logical types should be declared as 'nonterminals'
  1574 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1575 specifications.
  1576 
  1577 * Attributes 'induct' and 'cases': type or set names may now be
  1578 locally fixed variables as well.
  1579 
  1580 * Simplifier: can now control the depth to which conditional rewriting
  1581 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1582 Limit.
  1583 
  1584 * Simplifier: simplification procedures may now take the current
  1585 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1586 interface), which is very useful for calling the Simplifier
  1587 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1588 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1589 low-level mk_simproc no longer applies Logic.varify internally, to
  1590 allow for use in a context of fixed variables.
  1591 
  1592 * thin_tac now works even if the assumption being deleted contains !!
  1593 or ==>.  More generally, erule now works even if the major premise of
  1594 the elimination rule contains !! or ==>.
  1595 
  1596 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1597 
  1598 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1599 from Pure, which contains all common declarations already.  Both
  1600 theories are defined via plain Isabelle/Isar .thy files.
  1601 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1602 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1603 use isatool fixcpure to adapt your theory and ML sources.
  1604 
  1605 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1606 selections of theorems in named facts via index ranges.
  1607 
  1608 * 'print_theorems': in theory mode, really print the difference
  1609 wrt. the last state (works for interactive theory development only),
  1610 in proof mode print all local facts (cf. 'print_facts');
  1611 
  1612 * 'hide': option '(open)' hides only base names.
  1613 
  1614 * More efficient treatment of intermediate checkpoints in interactive
  1615 theory development.
  1616 
  1617 * Code generator is now invoked via code_module (incremental code
  1618 generation) and code_library (modular code generation, ML structures
  1619 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1620 must be quoted when used as identifiers.
  1621 
  1622 * New 'value' command for reading, evaluating and printing terms using
  1623 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1624 quoted when used as identifier.
  1625 
  1626 
  1627 *** Locales ***
  1628 
  1629 * New commands for the interpretation of locale expressions in
  1630 theories (1), locales (2) and proof contexts (3).  These generate
  1631 proof obligations from the expression specification.  After the
  1632 obligations have been discharged, theorems of the expression are added
  1633 to the theory, target locale or proof context.  The synopsis of the
  1634 commands is a follows:
  1635 
  1636   (1) interpretation expr inst
  1637   (2) interpretation target < expr
  1638   (3) interpret expr inst
  1639 
  1640 Interpretation in theories and proof contexts require a parameter
  1641 instantiation of terms from the current context.  This is applied to
  1642 specifications and theorems of the interpreted expression.
  1643 Interpretation in locales only permits parameter renaming through the
  1644 locale expression.  Interpretation is smart in that interpretations
  1645 that are active already do not occur in proof obligations, neither are
  1646 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1647 inspect active interpretations of a particular locale.  For details,
  1648 see the Isar Reference manual.  Examples can be found in
  1649 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1650 
  1651 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1652 'interpret' instead.
  1653 
  1654 * New context element 'constrains' for adding type constraints to
  1655 parameters.
  1656 
  1657 * Context expressions: renaming of parameters with syntax
  1658 redeclaration.
  1659 
  1660 * Locale declaration: 'includes' disallowed.
  1661 
  1662 * Proper static binding of attribute syntax -- i.e. types / terms /
  1663 facts mentioned as arguments are always those of the locale definition
  1664 context, independently of the context of later invocations.  Moreover,
  1665 locale operations (renaming and type / term instantiation) are applied
  1666 to attribute arguments as expected.
  1667 
  1668 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1669 actual attributes; rare situations may require Attrib.attribute to
  1670 embed those attributes into Attrib.src that lack concrete syntax.
  1671 Attribute implementations need to cooperate properly with the static
  1672 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1673 Attrib.XXX_thm etc. already do the right thing without further
  1674 intervention.  Only unusual applications -- such as "where" or "of"
  1675 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1676 on the context and the facts involved -- may have to assign parsed
  1677 values to argument tokens explicitly.
  1678 
  1679 * Changed parameter management in theorem generation for long goal
  1680 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1681 theorem statement in rare situations.
  1682 
  1683 * Locale inspection command 'print_locale' omits notes elements.  Use
  1684 'print_locale!' to have them included in the output.
  1685 
  1686 
  1687 *** Provers ***
  1688 
  1689 * Provers/hypsubst.ML: improved version of the subst method, for
  1690 single-step rewriting: it now works in bound variable contexts. New is
  1691 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1692 rewrite a different subterm than the original subst method, which is
  1693 still available as 'simplesubst'.
  1694 
  1695 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1696 and quasi orders.
  1697 
  1698 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1699 reflexive-transitive closure of relations.
  1700 
  1701 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1702 limit (previously hard-coded with a value of 20) user-definable.
  1703 
  1704 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1705 is peformed already.  Object-logics merely need to finish their
  1706 initial simpset configuration as before.  INCOMPATIBILITY.
  1707 
  1708 
  1709 *** HOL ***
  1710 
  1711 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1712 
  1713   syntax (epsilon)
  1714     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1715 
  1716 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1717 and x-symbol; use option '-m epsilon' to get it actually printed.
  1718 Moreover, the mathematically important symbolic identifier \<epsilon>
  1719 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1720 
  1721 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1722 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1723 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1724 support corresponding Isar calculations.
  1725 
  1726 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1727 instead of ":".
  1728 
  1729 * theory SetInterval: changed the syntax for open intervals:
  1730 
  1731   Old       New
  1732   {..n(}    {..<n}
  1733   {)n..}    {n<..}
  1734   {m..n(}   {m..<n}
  1735   {)m..n}   {m<..n}
  1736   {)m..n(}  {m<..<n}
  1737 
  1738 The old syntax is still supported but will disappear in the next
  1739 release.  For conversion use the following Emacs search and replace
  1740 patterns (these are not perfect but work quite well):
  1741 
  1742   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1743   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1744 
  1745 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1746 equalities in commutative rings; method 'algebra' provides a generic
  1747 interface.
  1748 
  1749 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1750 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1751 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1752 be a tuple pattern.
  1753 
  1754 Some new syntax forms are available:
  1755 
  1756   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1757   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1758   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1759   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1760 
  1761 The latter form "\<Sum>x < k. e" used to be based on a separate
  1762 function "Summation", which has been discontinued.
  1763 
  1764 * theory Finite_Set: in structured induction proofs, the insert case
  1765 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1766 (insert F x)'.
  1767 
  1768 * The 'refute' command has been extended to support a much larger
  1769 fragment of HOL, including axiomatic type classes, constdefs and
  1770 typedefs, inductive datatypes and recursion.
  1771 
  1772 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1773 Requires zChaff with proof generation to be installed.  See
  1774 HOL/ex/SAT_Examples.thy for examples.
  1775 
  1776 * Datatype induction via method 'induct' now preserves the name of the
  1777 induction variable. For example, when proving P(xs::'a list) by
  1778 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1779 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1780 in unstructured proof scripts.
  1781 
  1782 * Reworked implementation of records.  Improved scalability for
  1783 records with many fields, avoiding performance problems for type
  1784 inference. Records are no longer composed of nested field types, but
  1785 of nested extension types. Therefore the record type only grows linear
  1786 in the number of extensions and not in the number of fields.  The
  1787 top-level (users) view on records is preserved.  Potential
  1788 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1789 old record representation. The type generated for a record is called
  1790 <record_name>_ext_type.
  1791 
  1792 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1793 proofs triggered by a record definition or a simproc (if
  1794 quick_and_dirty is enabled).  Definitions of large records can take
  1795 quite long.
  1796 
  1797 New simproc record_upd_simproc for simplification of multiple record
  1798 updates enabled by default.  Moreover, trivial updates are also
  1799 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1800 occasionally, since simplification is more powerful by default.
  1801 
  1802 * typedef: proper support for polymorphic sets, which contain extra
  1803 type-variables in the term.
  1804 
  1805 * Simplifier: automatically reasons about transitivity chains
  1806 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1807 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1808 old proofs break occasionally as simplification may now solve more
  1809 goals than previously.
  1810 
  1811 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1812 present.  Works for all partial orders (class "order"), in particular
  1813 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1814 just like y <= x.
  1815 
  1816 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1817 bound variable or a constant then the let is unfolded.  Otherwise
  1818 first a is simplified to b, and then f b is simplified to g. If
  1819 possible we abstract b from g arriving at "let x = b in h x",
  1820 otherwise we unfold the let and arrive at g.  The simproc can be
  1821 enabled/disabled by the reference use_let_simproc.  Potential
  1822 INCOMPATIBILITY since simplification is more powerful by default.
  1823 
  1824 * Classical reasoning: the meson method now accepts theorems as arguments.
  1825 
  1826 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1827 jobs to provide advice on the provability of subgoals.
  1828 
  1829 * Theory OrderedGroup and Ring_and_Field: various additions and
  1830 improvements to faciliate calculations involving equalities and
  1831 inequalities.
  1832 
  1833 The following theorems have been eliminated or modified
  1834 (INCOMPATIBILITY):
  1835 
  1836   abs_eq             now named abs_of_nonneg
  1837   abs_of_ge_0        now named abs_of_nonneg
  1838   abs_minus_eq       now named abs_of_nonpos
  1839   imp_abs_id         now named abs_of_nonneg
  1840   imp_abs_neg_id     now named abs_of_nonpos
  1841   mult_pos           now named mult_pos_pos
  1842   mult_pos_le        now named mult_nonneg_nonneg
  1843   mult_pos_neg_le    now named mult_nonneg_nonpos
  1844   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1845   mult_neg           now named mult_neg_neg
  1846   mult_neg_le        now named mult_nonpos_nonpos
  1847 
  1848 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1849      
  1850      zero_le_square
  1851      not_square_less_zero 
  1852 
  1853   The following lemmas have been deleted from Real/RealPow:
  1854   
  1855      realpow_zero_zero
  1856      realpow_two
  1857      realpow_less
  1858      zero_le_power
  1859      realpow_two_le
  1860      abs_realpow_two
  1861      realpow_two_abs     
  1862 
  1863 * Theory Parity: added rules for simplifying exponents.
  1864 
  1865 * Theory List:
  1866 
  1867 The following theorems have been eliminated or modified
  1868 (INCOMPATIBILITY):
  1869 
  1870   list_all_Nil       now named list_all.simps(1)
  1871   list_all_Cons      now named list_all.simps(2)
  1872   list_all_conv      now named list_all_iff
  1873   set_mem_eq         now named mem_iff
  1874 
  1875 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1876 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1877 
  1878 
  1879 *** HOL-Complex ***
  1880 
  1881 * Theory RealDef: better support for embedding natural numbers and
  1882 integers in the reals.
  1883 
  1884 The following theorems have been eliminated or modified
  1885 (INCOMPATIBILITY):
  1886 
  1887   exp_ge_add_one_self  now requires no hypotheses
  1888   real_of_int_add      reversed direction of equality (use [symmetric])
  1889   real_of_int_minus    reversed direction of equality (use [symmetric])
  1890   real_of_int_diff     reversed direction of equality (use [symmetric])
  1891   real_of_int_mult     reversed direction of equality (use [symmetric])
  1892 
  1893 * Theory RComplete: expanded support for floor and ceiling functions.
  1894 
  1895 * Theory Ln is new, with properties of the natural logarithm
  1896 
  1897 * Hyperreal: There is a new type constructor "star" for making
  1898 nonstandard types.  The old type names are now type synonyms:
  1899 
  1900   hypreal = real star
  1901   hypnat = nat star
  1902   hcomplex = complex star
  1903 
  1904 * Hyperreal: Many groups of similarly-defined constants have been
  1905 replaced by polymorphic versions (INCOMPATIBILITY):
  1906 
  1907   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1908 
  1909   starset      <-- starsetNat, starsetC
  1910   *s*          <-- *sNat*, *sc*
  1911   starset_n    <-- starsetNat_n, starsetC_n
  1912   *sn*         <-- *sNatn*, *scn*
  1913   InternalSets <-- InternalNatSets, InternalCSets
  1914 
  1915   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1916   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1917   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1918   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1919   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1920 
  1921 * Hyperreal: Many type-specific theorems have been removed in favor of
  1922 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1923 
  1924   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1925   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1926   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1927   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1928   right_minus <-- hypreal_add_minus
  1929   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1930   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1931   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1932   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1933   mult_1_right <-- hcomplex_mult_one_right
  1934   mult_zero_left <-- hcomplex_mult_zero_left
  1935   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1936   right_distrib <-- hypnat_add_mult_distrib2
  1937   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1938   right_inverse <-- hypreal_mult_inverse
  1939   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1940   order_refl <-- {hypreal,hypnat}_le_refl
  1941   order_trans <-- {hypreal,hypnat}_le_trans
  1942   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1943   order_less_le <-- {hypreal,hypnat}_less_le
  1944   linorder_linear <-- {hypreal,hypnat}_le_linear
  1945   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1946   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1947   add_nonneg_nonneg <-- hypreal_le_add_order
  1948 
  1949 * Hyperreal: Separate theorems having to do with type-specific
  1950 versions of constants have been merged into theorems that apply to the
  1951 new polymorphic constants (INCOMPATIBILITY):
  1952 
  1953   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1954   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1955   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1956   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1957   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1958   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1959   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1960   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1961   STAR_diff <-- {STAR,STARC}_diff
  1962   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1963     STARC_hcomplex_of_complex}_image_subset
  1964   starset_n_Un <-- starset{Nat,C}_n_Un
  1965   starset_n_Int <-- starset{Nat,C}_n_Int
  1966   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1967   starset_n_diff <-- starset{Nat,C}_n_diff
  1968   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1969   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1970   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1971   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1972   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1973   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1974   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1975   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1976   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1977   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1978   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1979   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1980   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1981   starfun_diff <-- starfun{C,RC,CR}_diff
  1982   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1983   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1984   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1985   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1986   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1987   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1988   starfun_Id <-- starfunC_Id
  1989   starfun_approx <-- starfun{Nat,CR}_approx
  1990   starfun_capprox <-- starfun{C,RC}_capprox
  1991   starfun_abs <-- starfunNat_rabs
  1992   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1993   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1994   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1995   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1996   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1997   starfun_add_approx <-- starfunCR_add_approx
  1998   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1999   starfun_divide <-- starfun{C,CR,RC}_divide
  2000   starfun_n <-- starfun{Nat,C}_n
  2001   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2002   starfun_n_add <-- starfun{Nat,C}_n_add
  2003   starfun_n_add_minus <-- starfunNat_n_add_minus
  2004   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2005   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2006   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2007 
  2008   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2009   star_n_minus <-- {hypreal,hcomplex}_minus
  2010   star_n_diff <-- {hypreal,hcomplex}_diff
  2011   star_n_mult <-- {hypreal,hcomplex}_mult
  2012   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2013   star_n_le <-- {hypreal,hypnat}_le
  2014   star_n_less <-- {hypreal,hypnat}_less
  2015   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2016   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2017   star_n_abs <-- hypreal_hrabs
  2018   star_n_divide <-- hcomplex_divide
  2019 
  2020   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2021   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2022   star_of_diff <-- hypreal_of_real_diff
  2023   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2024   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2025   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2026   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2027   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2028   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2029   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2030   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2031   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2032   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2033   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2034   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2035   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2036   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2037   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2038   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2039   star_of_power <-- hypreal_of_real_power
  2040   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2041 
  2042 * Hyperreal: new method "transfer" that implements the transfer
  2043 principle of nonstandard analysis. With a subgoal that mentions
  2044 nonstandard types like "'a star", the command "apply transfer"
  2045 replaces it with an equivalent one that mentions only standard types.
  2046 To be successful, all free variables must have standard types; non-
  2047 standard variables must have explicit universal quantifiers.
  2048 
  2049 * Hyperreal: A theory of Taylor series.
  2050 
  2051 
  2052 *** HOLCF ***
  2053 
  2054 * Discontinued special version of 'constdefs' (which used to support
  2055 continuous functions) in favor of the general Pure one with full
  2056 type-inference.
  2057 
  2058 * New simplification procedure for solving continuity conditions; it
  2059 is much faster on terms with many nested lambda abstractions (cubic
  2060 instead of exponential time).
  2061 
  2062 * New syntax for domain package: selector names are now optional.
  2063 Parentheses should be omitted unless argument is lazy, for example:
  2064 
  2065   domain 'a stream = cons "'a" (lazy "'a stream")
  2066 
  2067 * New command 'fixrec' for defining recursive functions with pattern
  2068 matching; defining multiple functions with mutual recursion is also
  2069 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2070 sinr, or any data constructor defined by the domain package. The given
  2071 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2072 syntax and examples.
  2073 
  2074 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2075 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2076 but the proof obligation additionally includes an admissibility
  2077 requirement. The packages generate instances of class cpo or pcpo,
  2078 with continuity and strictness theorems for Rep and Abs.
  2079 
  2080 * HOLCF: Many theorems have been renamed according to a more standard naming
  2081 scheme (INCOMPATIBILITY):
  2082 
  2083   foo_inject:  "foo$x = foo$y ==> x = y"
  2084   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2085   foo_less:    "(foo$x << foo$y) = (x << y)"
  2086   foo_strict:  "foo$UU = UU"
  2087   foo_defined: "... ==> foo$x ~= UU"
  2088   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2089 
  2090 
  2091 *** ZF ***
  2092 
  2093 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2094 including the First Isomorphism Theorem (on quotienting by the kernel
  2095 of a homomorphism).
  2096 
  2097 * ZF/Simplifier: install second copy of type solver that actually
  2098 makes use of TC rules declared to Isar proof contexts (or locales);
  2099 the old version is still required for ML proof scripts.
  2100 
  2101 
  2102 *** Cube ***
  2103 
  2104 * Converted to Isar theory format; use locales instead of axiomatic
  2105 theories.
  2106 
  2107 
  2108 *** ML ***
  2109 
  2110 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2111 for ||>, ||>>, |>>,
  2112 
  2113 * Pure/library.ML no longer defines its own option datatype, but uses
  2114 that of the SML basis, which has constructors NONE and SOME instead of
  2115 None and Some, as well as exception Option.Option instead of OPTION.
  2116 The functions the, if_none, is_some, is_none have been adapted
  2117 accordingly, while Option.map replaces apsome.
  2118 
  2119 * Pure/library.ML: the exception LIST has been given up in favour of
  2120 the standard exceptions Empty and Subscript, as well as
  2121 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2122 superceded by the standard hd and tl functions etc.
  2123 
  2124 A number of basic list functions are no longer exported to the ML
  2125 toplevel, as they are variants of predefined functions.  The following
  2126 suggests how one can translate existing code:
  2127 
  2128     rev_append xs ys = List.revAppend (xs, ys)
  2129     nth_elem (i, xs) = List.nth (xs, i)
  2130     last_elem xs = List.last xs
  2131     flat xss = List.concat xss
  2132     seq fs = List.app fs
  2133     partition P xs = List.partition P xs
  2134     mapfilter f xs = List.mapPartial f xs
  2135 
  2136 * Pure/library.ML: several combinators for linear functional
  2137 transformations, notably reverse application and composition:
  2138 
  2139   x |> f                f #> g
  2140   (x, y) |-> f          f #-> g
  2141 
  2142 * Pure/library.ML: introduced/changed precedence of infix operators:
  2143 
  2144   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2145   infix 2 ?;
  2146   infix 3 o oo ooo oooo;
  2147   infix 4 ~~ upto downto;
  2148 
  2149 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2150 infix operators.
  2151 
  2152 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2153 fold_map support linear functional transformations and nesting.  For
  2154 example:
  2155 
  2156   fold f [x1, ..., xN] y =
  2157     y |> f x1 |> ... |> f xN
  2158 
  2159   (fold o fold) f [xs1, ..., xsN] y =
  2160     y |> fold f xs1 |> ... |> fold f xsN
  2161 
  2162   fold f [x1, ..., xN] =
  2163     f x1 #> ... #> f xN
  2164 
  2165   (fold o fold) f [xs1, ..., xsN] =
  2166     fold f xs1 #> ... #> fold f xsN
  2167 
  2168 * Pure/library.ML: the following selectors on type 'a option are
  2169 available:
  2170 
  2171   the:               'a option -> 'a  (*partial*)
  2172   these:             'a option -> 'a  where 'a = 'b list
  2173   the_default: 'a -> 'a option -> 'a
  2174   the_list:          'a option -> 'a list
  2175 
  2176 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2177 basic operations for association lists, following natural argument
  2178 order; moreover the explicit equality predicate passed here avoids
  2179 potentially expensive polymorphic runtime equality checks.
  2180 The old functions may be expressed as follows:
  2181 
  2182   assoc = uncurry (AList.lookup (op =))
  2183   assocs = these oo AList.lookup (op =)
  2184   overwrite = uncurry (AList.update (op =)) o swap
  2185 
  2186 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2187 
  2188   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2189   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2190 
  2191 replacing make_keylist and keyfilter (occassionally used)
  2192 Naive rewrites:
  2193 
  2194   make_keylist = AList.make
  2195   keyfilter = AList.find (op =)
  2196 
  2197 * eq_fst and eq_snd now take explicit equality parameter, thus
  2198   avoiding eqtypes. Naive rewrites:
  2199 
  2200     eq_fst = eq_fst (op =)
  2201     eq_snd = eq_snd (op =)
  2202 
  2203 * Removed deprecated apl and apr (rarely used).
  2204   Naive rewrites:
  2205 
  2206     apl (n, op) =>>= curry op n
  2207     apr (op, m) =>>= fn n => op (n, m)
  2208 
  2209 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2210 provides a reasonably efficient light-weight implementation of sets as
  2211 lists.
  2212 
  2213 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2214 few new operations; existing lookup and update are now curried to
  2215 follow natural argument order (for use with fold etc.);
  2216 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2217 
  2218 * Pure/General: output via the Isabelle channels of
  2219 writeln/warning/error etc. is now passed through Output.output, with a
  2220 hook for arbitrary transformations depending on the print_mode
  2221 (cf. Output.add_mode -- the first active mode that provides a output
  2222 function wins).  Already formatted output may be embedded into further
  2223 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2224 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2225 accommodate easy composition of diagnostic messages etc.  Programmers
  2226 rarely need to care about Output.output or Output.raw at all, with
  2227 some notable exceptions: Output.output is required when bypassing the
  2228 standard channels (writeln etc.), or in token translations to produce
  2229 properly formatted results; Output.raw is required when capturing
  2230 already output material that will eventually be presented to the user
  2231 a second time.  For the default print mode, both Output.output and
  2232 Output.raw have no effect.
  2233 
  2234 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2235 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2236 cumulative results are displayed at the end of a batch session.
  2237 
  2238 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2239 replaced by File.platform_path and File.shell_path (with appropriate
  2240 hooks).  This provides a clean interface for unusual systems where the
  2241 internal and external process view of file names are different.
  2242 
  2243 * Pure: more efficient orders for basic syntactic entities: added
  2244 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2245 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2246 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2247 orders now -- potential INCOMPATIBILITY for code that depends on a
  2248 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2249 Library.sort_strings on result).
  2250 
  2251 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2252 fold_types traverse types/terms from left to right, observing natural
  2253 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2254 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2255 
  2256 * Pure: name spaces have been refined, with significant changes of the
  2257 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2258 to extern(_table).  The plain name entry path is superceded by a
  2259 general 'naming' context, which also includes the 'policy' to produce
  2260 a fully qualified name and external accesses of a fully qualified
  2261 name; NameSpace.extend is superceded by context dependent
  2262 Sign.declare_name.  Several theory and proof context operations modify
  2263 the naming context.  Especially note Theory.restore_naming and
  2264 ProofContext.restore_naming to get back to a sane state; note that
  2265 Theory.add_path is no longer sufficient to recover from
  2266 Theory.absolute_path in particular.
  2267 
  2268 * Pure: new flags short_names (default false) and unique_names
  2269 (default true) for controlling output of qualified names.  If
  2270 short_names is set, names are printed unqualified.  If unique_names is
  2271 reset, the name prefix is reduced to the minimum required to achieve
  2272 the original result when interning again, even if there is an overlap
  2273 with earlier declarations.
  2274 
  2275 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2276 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2277 (useful for printing error messages).  INCOMPATIBILITY.
  2278 
  2279 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2280 Theory.theory are now identified, referring to the universal
  2281 Context.theory (see Pure/context.ML).  Actual signature and theory
  2282 content is managed as theory data.  The old code and interfaces were
  2283 spread over many files and structures; the new arrangement introduces
  2284 considerable INCOMPATIBILITY to gain more clarity:
  2285 
  2286   Context -- theory management operations (name, identity, inclusion,
  2287     parents, ancestors, merge, etc.), plus generic theory data;
  2288 
  2289   Sign -- logical signature and syntax operations (declaring consts,
  2290     types, etc.), plus certify/read for common entities;
  2291 
  2292   Theory -- logical theory operations (stating axioms, definitions,
  2293     oracles), plus a copy of logical signature operations (consts,
  2294     types, etc.); also a few basic management operations (Theory.copy,
  2295     Theory.merge, etc.)
  2296 
  2297 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2298 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2299 for convenience -- they merely return the theory.
  2300 
  2301 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2302 
  2303 * Pure: the Isar proof context type is already defined early in Pure
  2304 as Context.proof (note that ProofContext.context and Proof.context are
  2305 aliases, where the latter is the preferred name).  This enables other
  2306 Isabelle components to refer to that type even before Isar is present.
  2307 
  2308 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2309 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2310 any of these kinds.  For example, Sign.intern typeK is now
  2311 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2312 Theory.hide_types.  Also note that former
  2313 Theory.hide_classes/types/consts are now
  2314 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2315 internalize their arguments!  INCOMPATIBILITY.
  2316 
  2317 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2318 datatype thmref (with constructors Name and NameSelection) instead of
  2319 plain string -- INCOMPATIBILITY;
  2320 
  2321 * Pure: cases produced by proof methods specify options, where NONE
  2322 means to remove case bindings -- INCOMPATIBILITY in
  2323 (RAW_)METHOD_CASES.
  2324 
  2325 * Pure: the following operations retrieve axioms or theorems from a
  2326 theory node or theory hierarchy, respectively:
  2327 
  2328   Theory.axioms_of: theory -> (string * term) list
  2329   Theory.all_axioms_of: theory -> (string * term) list
  2330   PureThy.thms_of: theory -> (string * thm) list
  2331   PureThy.all_thms_of: theory -> (string * thm) list
  2332 
  2333 * Pure: print_tac now outputs the goal through the trace channel.
  2334 
  2335 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2336 Reference Toplevel.debug (default false) controls detailed printing
  2337 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2338 controls execution profiling -- set to 1 for time and 2 for space
  2339 (both increase the runtime).
  2340 
  2341 * Isar session: The initial use of ROOT.ML is now always timed,
  2342 i.e. the log will show the actual process times, in contrast to the
  2343 elapsed wall-clock time that the outer shell wrapper produces.
  2344 
  2345 * Simplifier: improved handling of bound variables (nameless
  2346 representation, avoid allocating new strings).  Simprocs that invoke
  2347 the Simplifier recursively should use Simplifier.inherit_bounds to
  2348 avoid local name clashes.  Failure to do so produces warnings
  2349 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2350 for further details.
  2351 
  2352 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2353 bindings for all theorems stored within a given theory; this may help
  2354 in porting non-Isar theories to Isar ones, while keeping ML proof
  2355 scripts for the time being.
  2356 
  2357 * ML operator HTML.with_charset specifies the charset begin used for
  2358 generated HTML files.  For example:
  2359 
  2360   HTML.with_charset "utf-8" use_thy "Hebrew";
  2361   HTML.with_charset "utf-8" use_thy "Chinese";
  2362 
  2363 
  2364 *** System ***
  2365 
  2366 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2367 isabelle, isatool etc.).
  2368 
  2369 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2370 isatool doc, isatool mkdir, display_drafts etc.).
  2371 
  2372 * isatool usedir: option -f allows specification of the ML file to be
  2373 used by Isabelle; default is ROOT.ML.
  2374 
  2375 * New isatool version outputs the version identifier of the Isabelle
  2376 distribution being used.
  2377 
  2378 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2379 (containing Boolean satisfiability problems) into Isabelle/HOL
  2380 theories.
  2381 
  2382 
  2383 
  2384 New in Isabelle2004 (April 2004)
  2385 --------------------------------
  2386 
  2387 *** General ***
  2388 
  2389 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2390   Replaces linorder.ML.
  2391 
  2392 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2393   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2394   (\<a>...\<z>), are now considered normal letters, and can therefore
  2395   be used anywhere where an ASCII letter (a...zA...Z) has until
  2396   now. COMPATIBILITY: This obviously changes the parsing of some
  2397   terms, especially where a symbol has been used as a binder, say
  2398   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2399   as an identifier.  Fix it by inserting a space around former
  2400   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2401   existing theory and ML files.
  2402 
  2403 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2404 
  2405 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2406   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2407   a normal (but invisible) letter. For multiple letter subscripts repeat
  2408   \<^isub> like this: x\<^isub>1\<^isub>2.
  2409 
  2410 * Pure: There are now sub-/superscripts that can span more than one
  2411   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2412   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2413   superscript. The new control characters are not identifier parts.
  2414 
  2415 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2416   content of "..." to the latex file instead of \isacntrl... . The "..."
  2417   may consist of any printable characters excluding the end bracket >.
  2418 
  2419 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2420   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2421   declare constants "final", which prevents their being given a definition
  2422   later.  It is useful for constants whose behaviour is fixed axiomatically
  2423   rather than definitionally, such as the meta-logic connectives.
  2424 
  2425 * Pure: 'instance' now handles general arities with general sorts
  2426   (i.e. intersections of classes),
  2427 
  2428 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2429   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2430   It can be changed to alter the colors/layout of generated pages.
  2431 
  2432 
  2433 *** Isar ***
  2434 
  2435 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2436   cut_tac, subgoal_tac and thin_tac:
  2437   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2438     locales are no longer forced to write Isar proof scripts.
  2439     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2440     emulations.
  2441   - INCOMPATIBILITY: names of variables to be instantiated may no
  2442     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2443     This is consistent with the instantiation attribute "where".
  2444 
  2445 * Attributes "where" and "of":
  2446   - Now take type variables of instantiated theorem into account when reading
  2447     the instantiation string.  This fixes a bug that caused instantiated
  2448     theorems to have too special types in some circumstances.
  2449   - "where" permits explicit instantiations of type variables.
  2450 
  2451 * Calculation commands "moreover" and "also" no longer interfere with
  2452   current facts ("this"), admitting arbitrary combinations with "then"
  2453   and derived forms.
  2454 
  2455 * Locales:
  2456   - Goal statements involving the context element "includes" no longer
  2457     generate theorems with internal delta predicates (those ending on
  2458     "_axioms") in the premise.
  2459     Resolve particular premise with <locale>.intro to obtain old form.
  2460   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2461     specification and "includes" elements in goal statement.
  2462   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2463     [intro?] and [elim?] (respectively) by default.
  2464   - Experimental command for instantiation of locales in proof contexts:
  2465         instantiate <label>[<attrs>]: <loc>
  2466     Instantiates locale <loc> and adds all its theorems to the current context
  2467     taking into account their attributes.  Label and attrs are optional
  2468     modifiers, like in theorem declarations.  If present, names of
  2469     instantiated theorems are qualified with <label>, and the attributes
  2470     <attrs> are applied after any attributes these theorems might have already.
  2471       If the locale has assumptions, a chained fact of the form
  2472     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2473     are derived.  The command does not support old-style locales declared
  2474     with "locale (open)".
  2475       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2476 
  2477 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2478   (Isar) contexts.
  2479 
  2480 
  2481 *** HOL ***
  2482 
  2483 * Proof import: new image HOL4 contains the imported library from
  2484   the HOL4 system with about 2500 theorems. It is imported by
  2485   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2486   can be used like any other Isabelle image.  See
  2487   HOL/Import/HOL/README for more information.
  2488 
  2489 * Simplifier:
  2490   - Much improved handling of linear and partial orders.
  2491     Reasoners for linear and partial orders are set up for type classes
  2492     "linorder" and "order" respectively, and are added to the default simpset
  2493     as solvers.  This means that the simplifier can build transitivity chains
  2494     to solve goals from the assumptions.
  2495   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2496     of blast or auto after simplification become unnecessary because the goal
  2497     is solved by simplification already.
  2498 
  2499 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2500     all proved in axiomatic type classes for semirings, rings and fields.
  2501 
  2502 * Numerics:
  2503   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2504     now formalized using the Ring_and_Field theory mentioned above.
  2505   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2506     than before, because now they are set up once in a generic manner.
  2507   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2508     Look for the general versions in Ring_and_Field (and Power if they concern
  2509     exponentiation).
  2510 
  2511 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2512 
  2513 * Records:
  2514   - Record types are now by default printed with their type abbreviation
  2515     instead of the list of all field types. This can be configured via
  2516     the reference "print_record_type_abbr".
  2517   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2518     (not enabled by default).
  2519   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2520     EX x. x = sel r to True (not enabled by default).
  2521   - Tactic "record_split_simp_tac" to split and simplify records added.
  2522 
  2523 * 'specification' command added, allowing for definition by
  2524   specification.  There is also an 'ax_specification' command that
  2525   introduces the new constants axiomatically.
  2526 
  2527 * arith(_tac) is now able to generate counterexamples for reals as well.
  2528 
  2529 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2530 
  2531 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2532   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2533 
  2534 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2535   matrix theory to linear programming.
  2536 
  2537 * Unions and Intersections:
  2538   The latex output syntax of UN and INT has been changed
  2539   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2540   i.e. the index formulae has become a subscript.
  2541   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2542 
  2543 * Unions and Intersections over Intervals:
  2544   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2545   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2546   like in normal math, and corresponding versions for < and for intersection.
  2547 
  2548 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2549   lexicographic dictonary ordering has been added as "lexord".
  2550 
  2551 * ML: the legacy theory structures Int and List have been removed. They had
  2552   conflicted with ML Basis Library structures having the same names.
  2553 
  2554 * 'refute' command added to search for (finite) countermodels.  Only works
  2555   for a fragment of HOL.  The installation of an external SAT solver is
  2556   highly recommended.  See "HOL/Refute.thy" for details.
  2557 
  2558 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2559   formulae under an assignment of free variables to random values.
  2560   In contrast to 'refute', it can deal with inductive datatypes,
  2561   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2562   for examples.
  2563 
  2564 
  2565 *** HOLCF ***
  2566 
  2567 * Streams now come with concatenation and are part of the HOLCF image
  2568 
  2569 
  2570 
  2571 New in Isabelle2003 (May 2003)
  2572 ------------------------------
  2573 
  2574 *** General ***
  2575 
  2576 * Provers/simplifier:
  2577 
  2578   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2579     Assumptions are now subject to complete mutual simplification,
  2580     not just from left to right. The simplifier now preserves
  2581     the order of assumptions.
  2582 
  2583     Potential INCOMPATIBILITY:
  2584 
  2585     -- simp sometimes diverges where the old version did
  2586        not, e.g. invoking simp on the goal
  2587 
  2588         [| P (f x); y = x; f x = f y |] ==> Q
  2589 
  2590        now gives rise to the infinite reduction sequence
  2591 
  2592         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2593 
  2594        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2595        kind of problem.
  2596 
  2597     -- Tactics combining classical reasoner and simplification (such as auto)
  2598        are also affected by this change, because many of them rely on
  2599        simp. They may sometimes diverge as well or yield a different numbers
  2600        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2601        in case of problems. Sometimes subsequent calls to the classical
  2602        reasoner will fail because a preceeding call to the simplifier too
  2603        eagerly simplified the goal, e.g. deleted redundant premises.
  2604 
  2605   - The simplifier trace now shows the names of the applied rewrite rules
  2606 
  2607   - You can limit the number of recursive invocations of the simplifier
  2608     during conditional rewriting (where the simplifie tries to solve the
  2609     conditions before applying the rewrite rule):
  2610     ML "simp_depth_limit := n"
  2611     where n is an integer. Thus you can force termination where previously
  2612     the simplifier would diverge.
  2613 
  2614   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2615 
  2616   - No longer aborts on failed congruence proof.  Instead, the
  2617     congruence is ignored.
  2618 
  2619 * Pure: New generic framework for extracting programs from constructive
  2620   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2621   as HOL/Extraction for some case studies.
  2622 
  2623 * Pure: The main goal of the proof state is no longer shown by default, only
  2624 the subgoals. This behaviour is controlled by a new flag.
  2625    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2626 (ML: Proof.show_main_goal).
  2627 
  2628 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2629 rules whose conclusion matches subgoal 1:
  2630       PG menu: Isabelle/Isar -> Show me -> matching rules
  2631 The rules are ordered by how closely they match the subgoal.
  2632 In particular, rules that solve a subgoal outright are displayed first
  2633 (or rather last, the way they are printed).
  2634 (ML: ProofGeneral.print_intros())
  2635 
  2636 * Pure: New flag trace_unify_fail causes unification to print
  2637 diagnostic information (PG: in trace buffer) when it fails. This is
  2638 useful for figuring out why single step proofs like rule, erule or
  2639 assumption failed.
  2640 
  2641 * Pure: Locale specifications now produce predicate definitions
  2642 according to the body of text (covering assumptions modulo local
  2643 definitions); predicate "loc_axioms" covers newly introduced text,
  2644 while "loc" is cumulative wrt. all included locale expressions; the
  2645 latter view is presented only on export into the global theory
  2646 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2647 on the old view without predicates;
  2648 
  2649 * Pure: predefined locales "var" and "struct" are useful for sharing
  2650 parameters (as in CASL, for example); just specify something like
  2651 ``var x + var y + struct M'' as import;
  2652 
  2653 * Pure: improved thms_containing: proper indexing of facts instead of
  2654 raw theorems; check validity of results wrt. current name space;
  2655 include local facts of proof configuration (also covers active
  2656 locales), cover fixed variables in index; may use "_" in term
  2657 specification; an optional limit for the number of printed facts may
  2658 be given (the default is 40);
  2659 
  2660 * Pure: disallow duplicate fact bindings within new-style theory files
  2661 (batch-mode only);
  2662 
  2663 * Provers: improved induct method: assumptions introduced by case
  2664 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2665 the goal statement); "foo" still refers to all facts collectively;
  2666 
  2667 * Provers: the function blast.overloaded has been removed: all constants
  2668 are regarded as potentially overloaded, which improves robustness in exchange
  2669 for slight decrease in efficiency;
  2670 
  2671 * Provers/linorder: New generic prover for transitivity reasoning over
  2672 linear orders.  Note: this prover is not efficient!
  2673 
  2674 * Isar: preview of problems to finish 'show' now produce an error
  2675 rather than just a warning (in interactive mode);
  2676 
  2677 
  2678 *** HOL ***
  2679 
  2680 * arith(_tac)
  2681 
  2682  - Produces a counter example if it cannot prove a goal.
  2683    Note that the counter example may be spurious if the goal is not a formula
  2684    of quantifier-free linear arithmetic.
  2685    In ProofGeneral the counter example appears in the trace buffer.
  2686 
  2687  - Knows about div k and mod k where k is a numeral of type nat or int.
  2688 
  2689  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2690    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2691    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2692 
  2693 * simp's arithmetic capabilities have been enhanced a bit: it now
  2694 takes ~= in premises into account (by performing a case split);
  2695 
  2696 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2697 are distributed over a sum of terms;
  2698 
  2699 * New tactic "trans_tac" and method "trans" instantiate
  2700 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2701 "<=", "<" and "=").
  2702 
  2703 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2704 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2705 
  2706 * 'typedef' command has new option "open" to suppress the set
  2707 definition;
  2708 
  2709 * functions Min and Max on finite sets have been introduced (theory
  2710 Finite_Set);
  2711 
  2712 * attribute [symmetric] now works for relations as well; it turns
  2713 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2714 
  2715 * induct over a !!-quantified statement (say !!x1..xn):
  2716   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2717 
  2718 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2719 %x. None. Warning: empty_def now refers to the previously hidden definition
  2720 of the empty set.
  2721 
  2722 * Algebra: formalization of classical algebra.  Intended as base for
  2723 any algebraic development in Isabelle.  Currently covers group theory
  2724 (up to Sylow's theorem) and ring theory (Universal Property of
  2725 Univariate Polynomials).  Contributions welcome;
  2726 
  2727 * GroupTheory: deleted, since its material has been moved to Algebra;
  2728 
  2729 * Complex: new directory of the complex numbers with numeric constants,
  2730 nonstandard complex numbers, and some complex analysis, standard and
  2731 nonstandard (Jacques Fleuriot);
  2732 
  2733 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2734 
  2735 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2736 Fleuriot);
  2737 
  2738 * Real/HahnBanach: updated and adapted to locales;
  2739 
  2740 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2741 Gray and Kramer);
  2742 
  2743 * UNITY: added the Meier-Sanders theory of progress sets;
  2744 
  2745 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2746 as abstract algorithms, instantiated to the JVM;
  2747 
  2748 * Bali: Java source language formalization. Type system, operational
  2749 semantics, axiomatic semantics. Supported language features:
  2750 classes, interfaces, objects,virtual methods, static methods,
  2751 static/instance fields, arrays, access modifiers, definite
  2752 assignment, exceptions.
  2753 
  2754 
  2755 *** ZF ***
  2756 
  2757 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2758 universe, etc.);
  2759 
  2760 * Main ZF: virtually all theories converted to new-style format;
  2761 
  2762 
  2763 *** ML ***
  2764 
  2765 * Pure: Tactic.prove provides sane interface for internal proofs;
  2766 omits the infamous "standard" operation, so this is more appropriate
  2767 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2768 
  2769 * Pure: improved error reporting of simprocs;
  2770 
  2771 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2772 up simprocs;
  2773 
  2774 
  2775 *** Document preparation ***
  2776 
  2777 * uses \par instead of \\ for line breaks in theory text. This may
  2778 shift some page breaks in large documents. To get the old behaviour
  2779 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2780 
  2781 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2782 other packages
  2783 
  2784 * \<euro> now needs package babel/greek instead of marvosym (which
  2785 broke \Rightarrow)
  2786 
  2787 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2788 textcomp package)
  2789 
  2790 
  2791 
  2792 New in Isabelle2002 (March 2002)
  2793 --------------------------------
  2794 
  2795 *** Document preparation ***
  2796 
  2797 * greatly simplified document preparation setup, including more
  2798 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2799 instructive isatool mkdir; users should basically be able to get
  2800 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2801 users may run a separate document processing stage manually like this:
  2802 "isatool usedir -D output HOL Test && isatool document Test/output";
  2803 
  2804 * theory dependency graph may now be incorporated into documents;
  2805 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2806 with \includegraphics of LaTeX;
  2807 
  2808 * proper spacing of consecutive markup elements, especially text
  2809 blocks after section headings;
  2810 
  2811 * support bold style (for single symbols only), input syntax is like
  2812 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2813 
  2814 * \<bullet> is now output as bold \cdot by default, which looks much
  2815 better in printed text;
  2816 
  2817 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2818 note that these symbols are currently unavailable in Proof General /
  2819 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2820 
  2821 * isatool latex no longer depends on changed TEXINPUTS, instead
  2822 isatool document copies the Isabelle style files to the target
  2823 location;
  2824 
  2825 
  2826 *** Isar ***
  2827 
  2828 * Pure/Provers: improved proof by cases and induction;
  2829   - 'case' command admits impromptu naming of parameters (such as
  2830     "case (Suc n)");
  2831   - 'induct' method divinates rule instantiation from the inductive
  2832     claim; no longer requires excessive ?P bindings for proper
  2833     instantiation of cases;
  2834   - 'induct' method properly enumerates all possibilities of set/type
  2835     rules; as a consequence facts may be also passed through *type*
  2836     rules without further ado;
  2837   - 'induct' method now derives symbolic cases from the *rulified*
  2838     rule (before it used to rulify cases stemming from the internal
  2839     atomized version); this means that the context of a non-atomic
  2840     statement becomes is included in the hypothesis, avoiding the
  2841     slightly cumbersome show "PROP ?case" form;
  2842   - 'induct' may now use elim-style induction rules without chaining
  2843     facts, using ``missing'' premises from the goal state; this allows
  2844     rules stemming from inductive sets to be applied in unstructured
  2845     scripts, while still benefitting from proper handling of non-atomic
  2846     statements; NB: major inductive premises need to be put first, all
  2847     the rest of the goal is passed through the induction;
  2848   - 'induct' proper support for mutual induction involving non-atomic
  2849     rule statements (uses the new concept of simultaneous goals, see
  2850     below);
  2851   - append all possible rule selections, but only use the first
  2852     success (no backtracking);
  2853   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2854   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2855   - added 'print_induct_rules' (covered by help item in recent Proof
  2856     General versions);
  2857   - moved induct/cases attributes to Pure, methods to Provers;
  2858   - generic method setup instantiated for FOL and HOL;
  2859 
  2860 * Pure: support multiple simultaneous goal statements, for example
  2861 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2862 meta-level mechanism, this acts as if several individual goals had
  2863 been stated separately; in particular common proof methods need to be
  2864 repeated in order to cover all claims; note that a single elimination
  2865 step is *not* sufficient to establish the two conjunctions, so this
  2866 fails:
  2867 
  2868   assume "A & B" then have A and B ..   (*".." fails*)
  2869 
  2870 better use "obtain" in situations as above; alternative refer to
  2871 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2872 
  2873 * Pure: proper integration with ``locales''; unlike the original
  2874 version by Florian Kammller, Isar locales package high-level proof
  2875 contexts rather than raw logical ones (e.g. we admit to include
  2876 attributes everywhere); operations on locales include merge and
  2877 rename; support for implicit arguments (``structures''); simultaneous
  2878 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2879 some examples;
  2880 
  2881 * Pure: the following commands have been ``localized'', supporting a
  2882 target locale specification "(in name)": 'lemma', 'theorem',
  2883 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2884 stored both within the locale and at the theory level (exported and
  2885 qualified by the locale name);
  2886 
  2887 * Pure: theory goals may now be specified in ``long'' form, with
  2888 ad-hoc contexts consisting of arbitrary locale elements. for example
  2889 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2890 definitions may be given, too); the result is a meta-level rule with
  2891 the context elements being discharged in the obvious way;
  2892 
  2893 * Pure: new proof command 'using' allows to augment currently used
  2894 facts after a goal statement ('using' is syntactically analogous to
  2895 'apply', but acts on the goal's facts only); this allows chained facts
  2896 to be separated into parts given before and after a claim, as in
  2897 ``from a and b have C using d and e <proof>'';
  2898 
  2899 * Pure: renamed "antecedent" case to "rule_context";
  2900 
  2901 * Pure: new 'judgment' command records explicit information about the
  2902 object-logic embedding (used by several tools internally); no longer
  2903 use hard-wired "Trueprop";
  2904 
  2905 * Pure: added 'corollary' command;
  2906 
  2907 * Pure: fixed 'token_translation' command;
  2908 
  2909 * Pure: removed obsolete 'exported' attribute;
  2910 
  2911 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2912 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2913 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2914 
  2915 * Pure: method 'atomize' presents local goal premises as object-level
  2916 statements (atomic meta-level propositions); setup controlled via
  2917 rewrite rules declarations of 'atomize' attribute; example
  2918 application: 'induct' method with proper rule statements in improper
  2919 proof *scripts*;
  2920 
  2921 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2922 now consider the syntactic context of assumptions, giving a better
  2923 chance to get type-inference of the arguments right (this is
  2924 especially important for locales);
  2925 
  2926 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2927 mode;
  2928 
  2929 * Pure/obtain: the formal conclusion "thesis", being marked as
  2930 ``internal'', may no longer be reference directly in the text;
  2931 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2932 situations;
  2933 
  2934 * Pure: generic 'sym' attribute which declares a rule both as pure
  2935 'elim?' and for the 'symmetric' operation;
  2936 
  2937 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2938 text; the fixed correlation with particular command syntax has been
  2939 discontinued;
  2940 
  2941 * Pure: new method 'rules' is particularly well-suited for proof
  2942 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2943 but often produces more compact proof terms with less detours;
  2944 
  2945 * Pure/Provers/classical: simplified integration with pure rule
  2946 attributes and methods; the classical "intro?/elim?/dest?"
  2947 declarations coincide with the pure ones; the "rule" method no longer
  2948 includes classically swapped intros; "intro" and "elim" methods no
  2949 longer pick rules from the context; also got rid of ML declarations
  2950 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2951 INCOMPATIBILITY;
  2952 
  2953 * Provers/classical: attribute 'swapped' produces classical inversions
  2954 of introduction rules;
  2955 
  2956 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2957 rules instead of full simplifier context; 'iff' attribute handles
  2958 conditional rules;
  2959 
  2960 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2961 
  2962 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2963 "(permissive)" option to recover old behavior;
  2964 
  2965 * HOL: 'inductive' no longer features separate (collective) attributes
  2966 for 'intros' (was found too confusing);
  2967 
  2968 * HOL: properly declared induction rules less_induct and
  2969 wf_induct_rule;
  2970 
  2971 
  2972 *** HOL ***
  2973 
  2974 * HOL: moved over to sane numeral syntax; the new policy is as
  2975 follows:
  2976 
  2977   - 0 and 1 are polymorphic constants, which are defined on any
  2978   numeric type (nat, int, real etc.);
  2979 
  2980   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2981   binary representation internally;
  2982 
  2983   - type nat has special constructor Suc, and generally prefers Suc 0
  2984   over 1::nat and Suc (Suc 0) over 2::nat;
  2985 
  2986 This change may cause significant problems of INCOMPATIBILITY; here
  2987 are some hints on converting existing sources:
  2988 
  2989   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2990   entities, so expressions involving "-" (unary or binary minus) need
  2991   to be spaced properly;
  2992 
  2993   - existing occurrences of "1" may need to be constraint "1::nat" or
  2994   even replaced by Suc 0; similar for old "2";
  2995 
  2996   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2997 
  2998   - remove all special provisions on numerals in proofs;
  2999 
  3000 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3001 representation (depends on bin_arith_simps in the default context);
  3002 
  3003 * HOL: symbolic syntax for x^2 (numeral 2);
  3004 
  3005 * HOL: the class of all HOL types is now called "type" rather than
  3006 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3007 in axclass/classes, instance/arities, and (usually rare) occurrences
  3008 in typings (of consts etc.); internally the class is called
  3009 "HOL.type", ML programs should refer to HOLogic.typeS;
  3010 
  3011 * HOL/record package improvements:
  3012   - new derived operations "fields" to build a partial record section,
  3013     "extend" to promote a fixed record to a record scheme, and
  3014     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3015     declared as simp by default;
  3016   - shared operations ("more", "fields", etc.) now need to be always
  3017     qualified) --- potential INCOMPATIBILITY;
  3018   - removed "make_scheme" operations (use "make" with "extend") --
  3019     INCOMPATIBILITY;
  3020   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3021   - provides cases/induct rules for use with corresponding Isar
  3022     methods (for concrete records, record schemes, concrete more
  3023     parts, and schematic more parts -- in that order);
  3024   - internal definitions directly based on a light-weight abstract
  3025     theory of product types over typedef rather than datatype;
  3026 
  3027 * HOL: generic code generator for generating executable ML code from
  3028 specifications; specific support for HOL constructs such as inductive
  3029 datatypes and sets, as well as recursive functions; can be invoked
  3030 via 'generate_code' theory section;
  3031 
  3032 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3033 
  3034 * HOL: consolidated and renamed several theories.  In particular:
  3035         Ord.thy has been absorbed into HOL.thy
  3036         String.thy has been absorbed into List.thy
  3037 
  3038 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3039 (beware of argument permutation!);
  3040 
  3041 * HOL: linorder_less_split superseded by linorder_cases;
  3042 
  3043 * HOL/List: "nodups" renamed to "distinct";
  3044 
  3045 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3046 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3047   - Ex_def has changed, now need to use some_eq_ex
  3048 
  3049 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3050 in this (rare) case use:
  3051 
  3052   delSWrapper "split_all_tac"
  3053   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3054 
  3055 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3056 MAY FAIL;
  3057 
  3058 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3059 Isabelle's type classes, ^ on functions and relations has too general
  3060 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3061 necessary to attach explicit type constraints;
  3062 
  3063 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3064 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3065 renamed accordingly (eg "compI" -> "rel_compI").
  3066 
  3067 * HOL: syntax translations now work properly with numerals and records
  3068 expressions;
  3069 
  3070 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3071 of "lam" -- INCOMPATIBILITY;
  3072 
  3073 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3074 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3075 renamed "Product_Type.unit";
  3076 
  3077 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3078 
  3079 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3080 the "cases" method);
  3081 
  3082 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3083 Florian Kammller);
  3084 
  3085 * HOL/IMP: updated and converted to new-style theory format; several
  3086 parts turned into readable document, with proper Isar proof texts and
  3087 some explanations (by Gerwin Klein);
  3088 
  3089 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3090 
  3091 * HOL-Hyperreal is now a logic image;
  3092 
  3093 
  3094 *** HOLCF ***
  3095 
  3096 * Isar: consts/constdefs supports mixfix syntax for continuous
  3097 operations;
  3098 
  3099 * Isar: domain package adapted to new-style theory format, e.g. see
  3100 HOLCF/ex/Dnat.thy;
  3101 
  3102 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3103 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3104 lift.induct_tac, always use UU instead of Undef;
  3105 
  3106 * HOLCF/IMP: updated and converted to new-style theory;
  3107 
  3108 
  3109 *** ZF ***
  3110 
  3111 * Isar: proper integration of logic-specific tools and packages,
  3112 including theory commands '(co)inductive', '(co)datatype',
  3113 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3114 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3115 
  3116 * theory Main no longer includes AC; for the Axiom of Choice, base
  3117 your theory on Main_ZFC;
  3118 
  3119 * the integer library now covers quotients and remainders, with many
  3120 laws relating division to addition, multiplication, etc.;
  3121 
  3122 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3123 typeless version of the formalism;
  3124 
  3125 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3126 format;
  3127 
  3128 * ZF/Induct: new directory for examples of inductive definitions,
  3129 including theory Multiset for multiset orderings; converted to
  3130 new-style theory format;
  3131 
  3132 * ZF: many new theorems about lists, ordinals, etc.;
  3133 
  3134 
  3135 *** General ***
  3136 
  3137 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3138 variable proof controls level of detail: 0 = no proofs (only oracle
  3139 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3140 also ref manual for further ML interfaces;
  3141 
  3142 * Pure/axclass: removed obsolete ML interface
  3143 goal_subclass/goal_arity;
  3144 
  3145 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3146 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3147 separate tokens, so expressions involving minus need to be spaced
  3148 properly;
  3149 
  3150 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3151 rather than "infixl" or "infixr";
  3152 
  3153 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3154 sort constraint specifications in type inference; e.g. "x::_::foo"
  3155 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3156 type variable);
  3157 
  3158 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3159 control output of nested => (types); the default behavior is
  3160 "type_brackets";
  3161 
  3162 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3163 tokens into AST constants;
  3164 
  3165 * Pure/syntax: prefer later declarations of translations and print
  3166 translation functions; potential INCOMPATIBILITY: need to reverse
  3167 multiple declarations for same syntax element constant;
  3168 
  3169 * Pure/show_hyps reset by default (in accordance to existing Isar
  3170 practice);
  3171 
  3172 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3173 addSafter;
  3174 
  3175 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3176 as well;
  3177 
  3178 * system: tested support for MacOS X; should be able to get Isabelle +
  3179 Proof General to work in a plain Terminal after installing Poly/ML
  3180 (e.g. from the Isabelle distribution area) and GNU bash alone
  3181 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3182 support requires further installations, e.g. from
  3183 http://fink.sourceforge.net/);
  3184 
  3185 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3186 
  3187 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3188 of 40 MB), cf. ML_OPTIONS;
  3189 
  3190 * system: Proof General keywords specification is now part of the
  3191 Isabelle distribution (see etc/isar-keywords.el);
  3192 
  3193 * system: support for persistent Proof General sessions (refrain from
  3194 outdating all loaded theories on startup); user may create writable
  3195 logic images like this: ``isabelle -q HOL Test'';
  3196 
  3197 * system: smart selection of Isabelle process versus Isabelle
  3198 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3199 run both "isabelle" and "Isabelle" even if file names are badly
  3200 damaged (executable inspects the case of the first letter of its own
  3201 name); added separate "isabelle-process" and "isabelle-interface";
  3202 
  3203 * system: refrain from any attempt at filtering input streams; no
  3204 longer support ``8bit'' encoding of old isabelle font, instead proper
  3205 iso-latin characters may now be used; the related isatools
  3206 "symbolinput" and "nonascii" have disappeared as well;
  3207 
  3208 * system: removed old "xterm" interface (the print modes "xterm" and
  3209 "xterm_color" are still available for direct use in a suitable
  3210 terminal);
  3211 
  3212 
  3213 
  3214 New in Isabelle99-2 (February 2001)
  3215 -----------------------------------
  3216 
  3217 *** Overview of INCOMPATIBILITIES ***
  3218 
  3219 * HOL: please note that theories in the Library and elsewhere often use the
  3220 new-style (Isar) format; to refer to their theorems in an ML script you must
  3221 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3222 
  3223 * HOL: inductive package no longer splits induction rule aggressively,
  3224 but only as far as specified by the introductions given; the old
  3225 format may be recovered via ML function complete_split_rule or attribute
  3226 'split_rule (complete)';
  3227 
  3228 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3229 gfp_Tarski to gfp_unfold;
  3230 
  3231 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3232 
  3233 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3234 relation); infix "^^" has been renamed "``"; infix "``" has been
  3235 renamed "`"; "univalent" has been renamed "single_valued";
  3236 
  3237 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3238 operation;
  3239 
  3240 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3241 
  3242 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3243 
  3244 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3245 consequence, it is no longer monotonic wrt. the local goal context
  3246 (which is now passed through the inductive cases);
  3247 
  3248 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3249 \<gg> to \<ggreater>;
  3250 
  3251 
  3252 *** Document preparation ***
  3253 
  3254 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3255 available: are "it" for near math-mode best-style output, "sl" for
  3256 slanted text style, and "tt" for plain type-writer; if no
  3257 \isabellestyle command is given, output is according to slanted
  3258 type-writer);
  3259 
  3260 * support sub/super scripts (for single symbols only), input syntax is
  3261 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3262 
  3263 * some more standard symbols; see Appendix A of the system manual for
  3264 the complete list of symbols defined in isabellesym.sty;
  3265 
  3266 * improved isabelle style files; more abstract symbol implementation
  3267 (should now use \isamath{...} and \isatext{...} in custom symbol
  3268 definitions);
  3269 
  3270 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3271 state; Note that presentation of goal states does not conform to
  3272 actual human-readable proof documents.  Please do not include goal
  3273 states into document output unless you really know what you are doing!
  3274 
  3275 * proper indentation of antiquoted output with proportional LaTeX
  3276 fonts;
  3277 
  3278 * no_document ML operator temporarily disables LaTeX document
  3279 generation;
  3280 
  3281 * isatool unsymbolize tunes sources for plain ASCII communication;
  3282 
  3283 
  3284 *** Isar ***
  3285 
  3286 * Pure: Isar now suffers initial goal statements to contain unbound
  3287 schematic variables (this does not conform to actual readable proof
  3288 documents, due to unpredictable outcome and non-compositional proof
  3289 checking); users who know what they are doing may use schematic goals
  3290 for Prolog-style synthesis of proven results;
  3291 
  3292 * Pure: assumption method (an implicit finishing) now handles actual
  3293 rules as well;
  3294 
  3295 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3296 initial goal, declare "that" only as Pure intro (only for single
  3297 steps); the "that" rule assumption may now be involved in implicit
  3298 finishing, thus ".." becomes a feasible for trivial obtains;
  3299 
  3300 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3301 instance proofs may be performed by "..";
  3302 
  3303 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3304 statements as well;
  3305 
  3306 * Pure: more robust selection of calculational rules;
  3307 
  3308 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3309 rule (as well as the assumption rule);
  3310 
  3311 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3312 lemmas, using the graph browser tool;
  3313 
  3314 * Pure: predict failure of "show" in interactive mode;
  3315 
  3316 * Pure: 'thms_containing' now takes actual terms as arguments;
  3317 
  3318 * HOL: improved method 'induct' --- now handles non-atomic goals
  3319 (potential INCOMPATIBILITY); tuned error handling;
  3320 
  3321 * HOL: cases and induct rules now provide explicit hints about the
  3322 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3323 any remaining facts are inserted into the goal verbatim;
  3324 
  3325 * HOL: local contexts (aka cases) may now contain term bindings as
  3326 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3327 the result to be shown in each case;
  3328 
  3329 * HOL: added 'recdef_tc' command;
  3330 
  3331 * isatool convert assists in eliminating legacy ML scripts;
  3332 
  3333 
  3334 *** HOL ***
  3335 
  3336 * HOL/Library: a collection of generic theories to be used together
  3337 with main HOL; the theory loader path already includes this directory
  3338 by default; the following existing theories have been moved here:
  3339 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3340 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3341 
  3342 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3343 modelling and verification task performed in Isabelle/HOL +
  3344 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3345 
  3346 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3347 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3348 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3349 'domain', this makes the theory consistent with mathematical
  3350 literature;
  3351 
  3352 * HOL basics: added overloaded operations "inverse" and "divide"
  3353 (infix "/"), syntax for generic "abs" operation, generic summation
  3354 operator \<Sum>;
  3355 
  3356 * HOL/typedef: simplified package, provide more useful rules (see also
  3357 HOL/subset.thy);
  3358 
  3359 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3360 now expressed as a proper nested rule (old-style tactic scripts may
  3361 require atomize_strip_tac to cope with non-atomic premises);
  3362 
  3363 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3364 to "split_conv" (old name still available for compatibility);
  3365 
  3366 * HOL: improved concrete syntax for strings (e.g. allows translation
  3367 rules with string literals);
  3368 
  3369 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3370  and Fleuriot's mechanization of analysis, including the transcendental
  3371  functions for the reals;
  3372 
  3373 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3374 
  3375 
  3376 *** CTT ***
  3377 
  3378 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3379 "lam" is displayed as TWO lambda-symbols
  3380 
  3381 * CTT: theory Main now available, containing everything (that is, Bool
  3382 and Arith);
  3383 
  3384 
  3385 *** General ***
  3386 
  3387 * Pure: the Simplifier has been implemented properly as a derived rule
  3388 outside of the actual kernel (at last!); the overall performance
  3389 penalty in practical applications is about 50%, while reliability of
  3390 the Isabelle inference kernel has been greatly improved;
  3391 
  3392 * print modes "brackets" and "no_brackets" control output of nested =>
  3393 (types) and ==> (props); the default behaviour is "brackets";
  3394 
  3395 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3396 as assumptions as well;
  3397 
  3398 * system: support Poly/ML 4.0;
  3399 
  3400 * system: isatool install handles KDE version 1 or 2;
  3401 
  3402 
  3403 
  3404 New in Isabelle99-1 (October 2000)
  3405 ----------------------------------
  3406 
  3407 *** Overview of INCOMPATIBILITIES ***
  3408 
  3409 * HOL: simplification of natural numbers is much changed; to partly
  3410 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3411 issue the following ML commands:
  3412 
  3413   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3414   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3415 
  3416 * HOL: simplification no longer dives into case-expressions; this is
  3417 controlled by "t.weak_case_cong" for each datatype t;
  3418 
  3419 * HOL: nat_less_induct renamed to less_induct;
  3420 
  3421 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3422 fixsome to patch .thy and .ML sources automatically;
  3423 
  3424   select_equality  -> some_equality
  3425   select_eq_Ex     -> some_eq_ex
  3426   selectI2EX       -> someI2_ex
  3427   selectI2         -> someI2
  3428   selectI          -> someI
  3429   select1_equality -> some1_equality
  3430   Eps_sym_eq       -> some_sym_eq_trivial
  3431   Eps_eq           -> some_eq_trivial
  3432 
  3433 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3434 
  3435 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3436 instead);
  3437 
  3438 * HOL: the recursion equations generated by 'recdef' are now called
  3439 f.simps instead of f.rules;
  3440 
  3441 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3442 
  3443 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3444 sometimes be needed;
  3445 
  3446 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3447 
  3448 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3449 
  3450 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3451 product is now "<*>" instead of "Times"; the lexicographic product is
  3452 now "<*lex*>" instead of "**";
  3453 
  3454 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3455 of main HOL, but was unused); better use HOL's datatype package;
  3456 
  3457 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3458 the old syntax may be recovered as follows:
  3459 
  3460   syntax (symbols)
  3461     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3462       (infixl "\\<oplus>" 100)
  3463 
  3464 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3465 
  3466 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3467 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3468 internally;
  3469 
  3470 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3471 changed from A/r to A//r;
  3472 
  3473 * ZF: new treatment of arithmetic (nat & int) may break some old
  3474 proofs;
  3475 
  3476 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3477 rulify -> rule_format, elimify -> elim_format, ...);
  3478 
  3479 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3480 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3481 should have to change intro!! to intro? only); replaced "delrule" by
  3482 "rule del";
  3483 
  3484 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3485 
  3486 * Provers: strengthened force_tac by using new first_best_tac;
  3487 
  3488 * LaTeX document preparation: several changes of isabelle.sty (see
  3489 lib/texinputs);
  3490 
  3491 
  3492 *** Document preparation ***
  3493 
  3494 * formal comments (text blocks etc.) in new-style theories may now
  3495 contain antiquotations of thm/prop/term/typ/text to be presented
  3496 according to latex print mode; concrete syntax is like this:
  3497 @{term[show_types] "f(x) = a + x"};
  3498 
  3499 * isatool mkdir provides easy setup of Isabelle session directories,
  3500 including proper document sources;
  3501 
  3502 * generated LaTeX sources are now deleted after successful run
  3503 (isatool document -c); may retain a copy somewhere else via -D option
  3504 of isatool usedir;
  3505 
  3506 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3507 style files, achieving self-contained LaTeX sources and simplifying
  3508 LaTeX debugging;
  3509 
  3510 * old-style theories now produce (crude) LaTeX output as well;
  3511 
  3512 * browser info session directories are now self-contained (may be put
  3513 on WWW server seperately); improved graphs of nested sessions; removed
  3514 graph for 'all sessions';
  3515 
  3516 * several improvements in isabelle style files; \isabellestyle{it}
  3517 produces fake math mode output; \isamarkupheader is now \section by
  3518 default; see lib/texinputs/isabelle.sty etc.;
  3519 
  3520 
  3521 *** Isar ***
  3522 
  3523 * Isar/Pure: local results and corresponding term bindings are now
  3524 subject to Hindley-Milner polymorphism (similar to ML); this
  3525 accommodates incremental type-inference very nicely;
  3526 
  3527 * Isar/Pure: new derived language element 'obtain' supports
  3528 generalized existence reasoning;
  3529 
  3530 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3531 support accumulation of results, without applying any rules yet;
  3532 useful to collect intermediate results without explicit name
  3533 references, and for use with transitivity rules with more than 2
  3534 premises;
  3535 
  3536 * Isar/Pure: scalable support for case-analysis type proofs: new
  3537 'case' language element refers to local contexts symbolically, as
  3538 produced by certain proof methods; internally, case names are attached
  3539 to theorems as "tags";
  3540 
  3541 * Isar/Pure: theory command 'hide' removes declarations from
  3542 class/type/const name spaces;
  3543 
  3544 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3545 indicate potential overloading;
  3546 
  3547 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3548 
  3549 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3550 "{a,b,c}" instead of {a,b,c};
  3551 
  3552 * Isar/Pure now provides its own version of intro/elim/dest
  3553 attributes; useful for building new logics, but beware of confusion
  3554 with the version in Provers/classical;
  3555 
  3556 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3557 case name 'antecedent';
  3558 
  3559 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3560 to the current context is now done automatically);
  3561 
  3562 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3563 for definining proof methods in ML;
  3564 
  3565 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3566 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3567 most cases, one should have to change intro!! to intro? only);
  3568 replaced "delrule" by "rule del";
  3569 
  3570 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3571 'symmetric' attribute (the latter supercedes [RS sym]);
  3572 
  3573 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3574 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3575 well (including splits);
  3576 
  3577 * Isar/Provers: Simplifier and Classical methods now support all kind
  3578 of modifiers used in the past, including 'cong', 'iff', etc.
  3579 
  3580 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3581 of Simplifier and Classical reasoner);
  3582 
  3583 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3584 now support named cases; major packages (inductive, datatype, primrec,
  3585 recdef) support case names and properly name parameters;
  3586 
  3587 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3588 monotonicity conditions are extracted to be proven at end of
  3589 calculations;
  3590 
  3591 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3592 method anyway;
  3593 
  3594 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3595 split_if split_if_asm; datatype package provides theorems foo.splits =
  3596 foo.split foo.split_asm for each datatype;
  3597 
  3598 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3599 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3600 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3601 use "(cases (simplified))" method in proper proof texts);
  3602 
  3603 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3604 
  3605 * Isar: names of theorems etc. may be natural numbers as well;
  3606 
  3607 * Isar: 'pr' command: optional arguments for goals_limit and
  3608 ProofContext.prems_limit; no longer prints theory contexts, but only
  3609 proof states;
  3610 
  3611 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3612 additional print modes to be specified; e.g. "pr(latex)" will print
  3613 proof state according to the Isabelle LaTeX style;
  3614 
  3615 * Isar: improved support for emulating tactic scripts, including proof
  3616 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3617 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3618 (for HOL datatypes);
  3619 
  3620 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3621 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3622 'proof method scripts' have to be in depth-first order;
  3623 
  3624 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3625 
  3626 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3627 should instead use individual commands for printing items
  3628 (print_commands, print_methods etc.);
  3629 
  3630 * Isar: added 'nothing' --- the empty list of theorems;
  3631 
  3632 
  3633 *** HOL ***
  3634 
  3635 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3636 corresponding virtual machine and a specification of its bytecode
  3637 verifier and a lightweight bytecode verifier, including proofs of
  3638 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3639 Cornelia Pusch (see also the homepage of project Bali at
  3640 http://isabelle.in.tum.de/Bali/);
  3641 
  3642 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3643 Clemens Ballarin;
  3644 
  3645 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3646 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3647 Rasmussen;
  3648 
  3649 * HOL/Lattice: fundamental concepts of lattice theory and order
  3650 structures, including duals, properties of bounds versus algebraic
  3651 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3652 Theorem for complete lattices etc.; may also serve as a demonstration
  3653 for abstract algebraic reasoning using axiomatic type classes, and
  3654 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3655 
  3656 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3657 von Oheimb;
  3658 
  3659 * HOL/IMPP: extension of IMP with local variables and mutually
  3660 recursive procedures, by David von Oheimb;
  3661 
  3662 * HOL/Lambda: converted into new-style theory and document;
  3663 
  3664 * HOL/ex/Multiquote: example of multiple nested quotations and
  3665 anti-quotations -- basically a generalized version of de-Bruijn
  3666 representation; very useful in avoiding lifting of operations;
  3667 
  3668 * HOL/record: added general record equality rule to simpset; fixed
  3669 select-update simplification procedure to handle extended records as
  3670 well; admit "r" as field name;
  3671 
  3672 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3673 other numeric types and also as the identity of groups, rings, etc.;
  3674 
  3675 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3676 Types nat and int belong to this axclass;
  3677 
  3678 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3679    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3680    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3681   two terms #m*u and #n*u are replaced by #(m+n)*u
  3682     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3683   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3684     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3685 
  3686 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3687 powerful prover for predicate logic but knows nothing of clasets; see
  3688 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3689 
  3690 * HOL: new version of "case_tac" subsumes both boolean case split and
  3691 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3692 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3693 
  3694 * HOL: simplification no longer dives into case-expressions: only the
  3695 selector expression is simplified, but not the remaining arms; to
  3696 enable full simplification of case-expressions for datatype t, you may
  3697 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3698 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3699 
  3700 * HOL/recdef: the recursion equations generated by 'recdef' for
  3701 function 'f' are now called f.simps instead of f.rules; if all
  3702 termination conditions are proved automatically, these simplification
  3703 rules are added to the simpset, as in primrec; rules may be named
  3704 individually as well, resulting in a separate list of theorems for
  3705 each equation;
  3706 
  3707 * HOL/While is a new theory that provides a while-combinator. It
  3708 permits the definition of tail-recursive functions without the
  3709 provision of a termination measure. The latter is necessary once the
  3710 invariant proof rule for while is applied.
  3711 
  3712 * HOL: new (overloaded) notation for the set of elements below/above
  3713 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3714 
  3715 * HOL: theorems impI, allI, ballI bound as "strip";
  3716 
  3717 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3718 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3719 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3720 
  3721 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3722 
  3723 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3724 main HOL, but was unused);
  3725 
  3726 * HOL: fewer consts declared as global (e.g. have to refer to
  3727 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3728 
  3729 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3730 in case of overlap with user translations (e.g. judgements over
  3731 tuples); (note that the underlying logical represenation is still
  3732 bogus);
  3733 
  3734 
  3735 *** ZF ***
  3736 
  3737 * ZF: simplification automatically cancels common terms in arithmetic
  3738 expressions over nat and int;
  3739 
  3740 * ZF: new treatment of nat to minimize type-checking: all operators
  3741 coerce their operands to a natural number using the function natify,
  3742 making the algebraic laws unconditional;
  3743 
  3744 * ZF: as above, for int: operators coerce their operands to an integer
  3745 using the function intify;
  3746 
  3747 * ZF: the integer library now contains many of the usual laws for the
  3748 orderings, including $<=, and monotonicity laws for $+ and $*;
  3749 
  3750 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3751 simplification;
  3752 
  3753 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3754 to the simplifier and classical reasoner simultaneously;
  3755 
  3756 
  3757 *** General ***
  3758 
  3759 * Provers: blast_tac now handles actual object-logic rules as
  3760 assumptions; note that auto_tac uses blast_tac internally as well;
  3761 
  3762 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3763 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3764 
  3765 * Provers: delrules now handles destruct rules as well (no longer need
  3766 explicit make_elim);
  3767 
  3768 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3769   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3770 use instead the strong form,
  3771   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3772 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3773 from destruct-rules;
  3774 
  3775 * Provers: Simplifier.easy_setup provides a fast path to basic
  3776 Simplifier setup for new object-logics;
  3777 
  3778 * Pure: AST translation rules no longer require constant head on LHS;
  3779 
  3780 * Pure: improved name spaces: ambiguous output is qualified; support
  3781 for hiding of names;
  3782 
  3783 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3784 XSYMBOL_HOME; no longer need to do manual configuration in most
  3785 situations;
  3786 
  3787 * system: compression of ML heaps images may now be controlled via -c
  3788 option of isabelle and isatool usedir (currently only observed by
  3789 Poly/ML);
  3790 
  3791 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3792 useful for remote X11);
  3793 
  3794 * system: provide TAGS file for Isabelle sources;
  3795 
  3796 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3797 order;
  3798 
  3799 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3800 timing flag supersedes proof_timing and Toplevel.trace;
  3801 
  3802 * ML: new combinators |>> and |>>> for incremental transformations
  3803 with secondary results (e.g. certain theory extensions):
  3804 
  3805 * ML: PureThy.add_defs gets additional argument to indicate potential
  3806 overloading (usually false);
  3807 
  3808 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3809 results;
  3810 
  3811 
  3812 
  3813 New in Isabelle99 (October 1999)
  3814 --------------------------------
  3815 
  3816 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3817 
  3818 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3819 are no longer simplified.  (This allows the simplifier to unfold recursive
  3820 functional programs.)  To restore the old behaviour, declare
  3821 
  3822     Delcongs [if_weak_cong];
  3823 
  3824 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3825 complement;
  3826 
  3827 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3828 
  3829 * HOL/datatype: mutual_induct_tac no longer exists --
  3830   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3831 
  3832 * HOL/typedef: fixed type inference for representing set; type
  3833 arguments now have to occur explicitly on the rhs as type constraints;
  3834 
  3835 * ZF: The con_defs part of an inductive definition may no longer refer
  3836 to constants declared in the same theory;
  3837 
  3838 * HOL, ZF: the function mk_cases, generated by the inductive
  3839 definition package, has lost an argument.  To simplify its result, it
  3840 uses the default simpset instead of a supplied list of theorems.
  3841 
  3842 * HOL/List: the constructors of type list are now Nil and Cons;
  3843 
  3844 * Simplifier: the type of the infix ML functions
  3845         setSSolver addSSolver setSolver addSolver
  3846 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3847 for packaging solvers. A solver is created via
  3848         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3849 where the string argument is only a comment.
  3850 
  3851 
  3852 *** Proof tools ***
  3853 
  3854 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3855 decision procedure for linear arithmetic. Currently it is used for
  3856 types `nat', `int', and `real' in HOL (see below); it can, should and
  3857 will be instantiated for other types and logics as well.
  3858 
  3859 * The simplifier now accepts rewrite rules with flexible heads, eg
  3860      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3861   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3862   matching.
  3863 
  3864 
  3865 *** General ***
  3866 
  3867 * New Isabelle/Isar subsystem provides an alternative to traditional
  3868 tactical theorem proving; together with the ProofGeneral/isar user
  3869 interface it offers an interactive environment for developing human
  3870 readable proof documents (Isar == Intelligible semi-automated
  3871 reasoning); for further information see isatool doc isar-ref,
  3872 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3873 
  3874 * improved and simplified presentation of theories: better HTML markup
  3875 (including colors), graph views in several sizes; isatool usedir now
  3876 provides a proper interface for user theories (via -P option); actual
  3877 document preparation based on (PDF)LaTeX is available as well (for
  3878 new-style theories only); see isatool doc system for more information;
  3879 
  3880 * native support for Proof General, both for classic Isabelle and
  3881 Isabelle/Isar;
  3882 
  3883 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3884 using the graph browser tool;
  3885 
  3886 * Isabelle manuals now also available as PDF;
  3887 
  3888 * theory loader rewritten from scratch (may not be fully
  3889 bug-compatible); old loadpath variable has been replaced by show_path,
  3890 add_path, del_path, reset_path functions; new operations such as
  3891 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3892 isatool doc ref);
  3893 
  3894 * improved isatool install: option -k creates KDE application icon,
  3895 option -p DIR installs standalone binaries;
  3896 
  3897 * added ML_PLATFORM setting (useful for cross-platform installations);
  3898 more robust handling of platform specific ML images for SML/NJ;
  3899 
  3900 * the settings environment is now statically scoped, i.e. it is never
  3901 created again in sub-processes invoked from isabelle, isatool, or
  3902 Isabelle;
  3903 
  3904 * path element specification '~~' refers to '$ISABELLE_HOME';
  3905 
  3906 * in locales, the "assumes" and "defines" parts may be omitted if
  3907 empty;
  3908 
  3909 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3910 long arrows);
  3911 
  3912 * new print_mode "HTML";
  3913 
  3914 * new flag show_tags controls display of tags of theorems (which are
  3915 basically just comments that may be attached by some tools);
  3916 
  3917 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3918 mode and goal output format:
  3919 
  3920 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3921 244c244
  3922 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3923 ---
  3924 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3925 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3926 181c181
  3927 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3928 ---
  3929 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3930 
  3931 * function bind_thms stores lists of theorems (cf. bind_thm);
  3932 
  3933 * new shorthand tactics ftac, eatac, datac, fatac;
  3934 
  3935 * qed (and friends) now accept "" as result name; in that case the
  3936 theorem is not stored, but proper checks and presentation of the
  3937 result still apply;
  3938 
  3939 * theorem database now also indexes constants "Trueprop", "all",
  3940 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3941 
  3942 
  3943 *** HOL ***
  3944 
  3945 ** HOL arithmetic **
  3946 
  3947 * There are now decision procedures for linear arithmetic over nat and
  3948 int:
  3949 
  3950 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3951 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3952 are treated as atomic; subformulae not involving type `nat' or `int'
  3953 are ignored; quantified subformulae are ignored unless they are
  3954 positive universal or negative existential. The tactic has to be
  3955 invoked by hand and can be a little bit slow. In particular, the
  3956 running time is exponential in the number of occurrences of `min' and
  3957 `max', and `-' on `nat'.
  3958 
  3959 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3960 (negated) (in)equalities among the premises and the conclusion into
  3961 account (i.e. no compound formulae) and does not know about `min' and
  3962 `max', and `-' on `nat'. It is fast and is used automatically by the
  3963 simplifier.
  3964 
  3965 NB: At the moment, these decision procedures do not cope with mixed
  3966 nat/int formulae where the two parts interact, such as `m < n ==>
  3967 int(m) < int(n)'.
  3968 
  3969 * HOL/Numeral provides a generic theory of numerals (encoded
  3970 efficiently as bit strings); setup for types nat/int/real is in place;
  3971 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3972 int, existing theories and proof scripts may require a few additional
  3973 type constraints;
  3974 
  3975 * integer division and remainder can now be performed on constant
  3976 arguments;
  3977 
  3978 * many properties of integer multiplication, division and remainder
  3979 are now available;
  3980 
  3981 * An interface to the Stanford Validity Checker (SVC) is available through the
  3982 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3983 are proved automatically.  SVC must be installed separately, and its results
  3984 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3985 invocation of the underlying oracle).  For SVC see
  3986   http://verify.stanford.edu/SVC
  3987 
  3988 * IsaMakefile: the HOL-Real target now builds an actual image;
  3989 
  3990 
  3991 ** HOL misc **
  3992 
  3993 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3994 (in Isabelle/Isar) -- by Gertrud Bauer;
  3995 
  3996 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3997 analysis for assembly languages with subtypes;
  3998 
  3999 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4000 -- avoids syntactic ambiguities and treats state, transition, and
  4001 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4002 changed syntax and (many) tactics;
  4003 
  4004 * HOL/inductive: Now also handles more general introduction rules such
  4005   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4006   theorems are now maintained within the theory (maintained via the
  4007   "mono" attribute);
  4008 
  4009 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4010   (using function types) such as
  4011 
  4012   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4013 
  4014 * HOL/record: record_simproc (part of the default simpset) takes care
  4015 of selectors applied to updated records; record_split_tac is no longer
  4016 part of the default claset; update_defs may now be removed from the
  4017 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4018 
  4019   claset_ref () := claset() addSWrapper record_split_wrapper;
  4020   Delsimprocs [record_simproc]
  4021 
  4022 * HOL/typedef: fixed type inference for representing set; type
  4023 arguments now have to occur explicitly on the rhs as type constraints;
  4024 
  4025 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4026 names rather than an ML expression;
  4027 
  4028 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4029 supplied later.  Program schemes can be defined, such as
  4030     "While B C s = (if B s then While B C (C s) else s)"
  4031 where the well-founded relation can be chosen after B and C have been given.
  4032 
  4033 * HOL/List: the constructors of type list are now Nil and Cons;
  4034 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4035 course, ML tools referring to List.list.op # etc. have to be adapted;
  4036 
  4037 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4038 disabled by default; run isabelle with option -m HOL to get back to
  4039 the original Gordon/HOL-style output;
  4040 
  4041 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4042 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4043 
  4044 * HOL basic syntax simplified (more orthogonal): all variants of
  4045 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4046 Eps operator is provided as well: "SOME x. P[x]";
  4047 
  4048 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4049 
  4050 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4051 thus available for user theories;
  4052 
  4053 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4054 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4055 time;
  4056 
  4057 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4058 several times and then mp;
  4059 
  4060 
  4061 *** LK ***
  4062 
  4063 * the notation <<...>> is now available as a notation for sequences of
  4064 formulas;
  4065 
  4066 * the simplifier is now installed
  4067 
  4068 * the axiom system has been generalized (thanks to Soren Heilmann)
  4069 
  4070 * the classical reasoner now has a default rule database
  4071 
  4072 
  4073 *** ZF ***
  4074 
  4075 * new primrec section allows primitive recursive functions to be given
  4076 directly (as in HOL) over datatypes and the natural numbers;
  4077 
  4078 * new tactics induct_tac and exhaust_tac for induction (or case
  4079 analysis) over datatypes and the natural numbers;
  4080 
  4081 * the datatype declaration of type T now defines the recursor T_rec;
  4082 
  4083 * simplification automatically does freeness reasoning for datatype
  4084 constructors;
  4085 
  4086 * automatic type-inference, with AddTCs command to insert new
  4087 type-checking rules;
  4088 
  4089 * datatype introduction rules are now added as Safe Introduction rules
  4090 to the claset;
  4091 
  4092 * the syntax "if P then x else y" is now available in addition to
  4093 if(P,x,y);
  4094 
  4095 
  4096 *** Internal programming interfaces ***
  4097 
  4098 * tuned simplifier trace output; new flag debug_simp;
  4099 
  4100 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4101 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4102 
  4103 * AxClass.axclass_tac lost the theory argument;
  4104 
  4105 * tuned current_goals_markers semantics: begin / end goal avoids
  4106 printing empty lines;
  4107 
  4108 * removed prs and prs_fn hook, which was broken because it did not
  4109 include \n in its semantics, forcing writeln to add one
  4110 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4111 string -> unit if you really want to output text without newline;
  4112 
  4113 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4114 plain output, interface builders may have to enable 'isabelle_font'
  4115 mode to get Isabelle font glyphs as before;
  4116 
  4117 * refined token_translation interface; INCOMPATIBILITY: output length
  4118 now of type real instead of int;
  4119 
  4120 * theory loader actions may be traced via new ThyInfo.add_hook
  4121 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4122 your own database of information attached to *whole* theories -- as
  4123 opposed to intra-theory data slots offered via TheoryDataFun;
  4124 
  4125 * proper handling of dangling sort hypotheses (at last!);
  4126 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4127 extra sort hypotheses that can be witnessed from the type signature;
  4128 the force_strip_shyps flag is gone, any remaining shyps are simply
  4129 left in the theorem (with a warning issued by strip_shyps_warning);
  4130 
  4131 
  4132 
  4133 New in Isabelle98-1 (October 1998)
  4134 ----------------------------------
  4135 
  4136 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4137 
  4138 * several changes of automated proof tools;
  4139 
  4140 * HOL: major changes to the inductive and datatype packages, including
  4141 some minor incompatibilities of theory syntax;
  4142 
  4143 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4144 called `inj_on';
  4145 
  4146 * HOL: removed duplicate thms in Arith:
  4147   less_imp_add_less  should be replaced by  trans_less_add1
  4148   le_imp_add_le      should be replaced by  trans_le_add1
  4149 
  4150 * HOL: unary minus is now overloaded (new type constraints may be
  4151 required);
  4152 
  4153 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4154 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4155 now taken as an integer constant.
  4156 
  4157 * Pure: ML function 'theory_of' renamed to 'theory';
  4158 
  4159 
  4160 *** Proof tools ***
  4161 
  4162 * Simplifier:
  4163   1. Asm_full_simp_tac is now more aggressive.
  4164      1. It will sometimes reorient premises if that increases their power to
  4165         simplify.
  4166      2. It does no longer proceed strictly from left to right but may also
  4167         rotate premises to achieve further simplification.
  4168      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4169      old Asm_full_simp_tac in that it does not rotate premises.
  4170   2. The simplifier now knows a little bit about nat-arithmetic.
  4171 
  4172 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4173 allows for selected deletion of wrappers, by introduction of names for
  4174 wrapper functionals.  This implies that addbefore, addSbefore,
  4175 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4176 and that adding two tactics with the same name overwrites the first
  4177 one (emitting a warning).
  4178   type wrapper = (int -> tactic) -> (int -> tactic)
  4179   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4180   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4181   delWrapper, delSWrapper: claset *  string            -> claset
  4182   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4183 
  4184 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4185 semantics; addbefore now affects only the unsafe part of step_tac
  4186 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4187 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4188 by Force_tac;
  4189 
  4190 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4191 compWrapper; added safe wrapper (and access functions for it);
  4192 
  4193 * HOL/split_all_tac is now much faster and fails if there is nothing
  4194 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4195 and the names of the automatically generated variables have changed.
  4196 split_all_tac has moved within claset() from unsafe wrappers to safe
  4197 wrappers, which means that !!-bound variables are split much more
  4198 aggressively, and safe_tac and clarify_tac now split such variables.
  4199 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4200 Note: the same holds for record_split_tac, which does the job of
  4201 split_all_tac for record fields.
  4202 
  4203 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4204 permanently to the default simpset using Addsplits just like
  4205 Addsimps. They can be removed via Delsplits just like
  4206 Delsimps. Lower-case versions are also available.
  4207 
  4208 * HOL/Simplifier: The rule split_if is now part of the default
  4209 simpset. This means that the simplifier will eliminate all occurrences
  4210 of if-then-else in the conclusion of a goal. To prevent this, you can
  4211 either remove split_if completely from the default simpset by
  4212 `Delsplits [split_if]' or remove it in a specific call of the
  4213 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4214 other case splitting rules to/from the default simpset: every datatype
  4215 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4216 t is the name of the datatype).
  4217 
  4218 * Classical reasoner / Simplifier combination: new force_tac (and
  4219 derivatives Force_tac, force) combines rewriting and classical
  4220 reasoning (and whatever other tools) similarly to auto_tac, but is
  4221 aimed to solve the given subgoal completely.
  4222 
  4223 
  4224 *** General ***
  4225 
  4226 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4227 and `goalw': the theory is no longer needed as an explicit argument -
  4228 the current theory context is used; assumptions are no longer returned
  4229 at the ML-level unless one of them starts with ==> or !!; it is
  4230 recommended to convert to these new commands using isatool fixgoal
  4231 (backup your sources first!);
  4232 
  4233 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4234 the current theory context, and 'theory' to lookup stored theories;
  4235 
  4236 * new theory section 'locale' for declaring constants, assumptions and
  4237 definitions that have local scope;
  4238 
  4239 * new theory section 'nonterminals' for purely syntactic types;
  4240 
  4241 * new theory section 'setup' for generic ML setup functions
  4242 (e.g. package initialization);
  4243 
  4244 * the distribution now includes Isabelle icons: see
  4245 lib/logo/isabelle-{small,tiny}.xpm;
  4246 
  4247 * isatool install - install binaries with absolute references to
  4248 ISABELLE_HOME/bin;
  4249 
  4250 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4251 
  4252 * print mode 'emacs' reserved for Isamode;
  4253 
  4254 * support multiple print (ast) translations per constant name;
  4255 
  4256 * theorems involving oracles are now printed with a suffixed [!];
  4257 
  4258 
  4259 *** HOL ***
  4260 
  4261 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4262 
  4263 * HOL/inductive package reorganized and improved: now supports mutual
  4264 definitions such as
  4265 
  4266   inductive EVEN ODD
  4267     intrs
  4268       null "0 : EVEN"
  4269       oddI "n : EVEN ==> Suc n : ODD"
  4270       evenI "n : ODD ==> Suc n : EVEN"
  4271 
  4272 new theorem list "elims" contains an elimination rule for each of the
  4273 recursive sets; inductive definitions now handle disjunctive premises
  4274 correctly (also ZF);
  4275 
  4276 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4277 "mutual_induct" no longer exists - the induction rule is always
  4278 contained in "induct";
  4279 
  4280 
  4281 * HOL/datatype package re-implemented and greatly improved: now
  4282 supports mutually recursive datatypes such as
  4283 
  4284   datatype
  4285     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4286             | SUM ('a aexp) ('a aexp)
  4287             | DIFF ('a aexp) ('a aexp)
  4288             | NUM 'a
  4289   and
  4290     'a bexp = LESS ('a aexp) ('a aexp)
  4291             | AND ('a bexp) ('a bexp)
  4292             | OR ('a bexp) ('a bexp)
  4293 
  4294 as well as indirectly recursive datatypes such as
  4295 
  4296   datatype
  4297     ('a, 'b) term = Var 'a
  4298                   | App 'b ((('a, 'b) term) list)
  4299 
  4300 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4301 induction on mutually / indirectly recursive datatypes.
  4302 
  4303 Primrec equations are now stored in theory and can be accessed via
  4304 <function_name>.simps.
  4305 
  4306 INCOMPATIBILITIES:
  4307 
  4308   - Theories using datatypes must now have theory Datatype as an
  4309     ancestor.
  4310   - The specific <typename>.induct_tac no longer exists - use the
  4311     generic induct_tac instead.
  4312   - natE has been renamed to nat.exhaust - use exhaust_tac
  4313     instead of res_inst_tac ... natE. Note that the variable
  4314     names in nat.exhaust differ from the names in natE, this
  4315     may cause some "fragile" proofs to fail.
  4316   - The theorems split_<typename>_case and split_<typename>_case_asm
  4317     have been renamed to <typename>.split and <typename>.split_asm.
  4318   - Since default sorts of type variables are now handled correctly,
  4319     some datatype definitions may have to be annotated with explicit
  4320     sort constraints.
  4321   - Primrec definitions no longer require function name and type
  4322     of recursive argument.
  4323 
  4324 Consider using isatool fixdatatype to adapt your theories and proof
  4325 scripts to the new package (backup your sources first!).
  4326 
  4327 
  4328 * HOL/record package: considerably improved implementation; now
  4329 includes concrete syntax for record types, terms, updates; theorems
  4330 for surjective pairing and splitting !!-bound record variables; proof
  4331 support is as follows:
  4332 
  4333   1) standard conversions (selectors or updates applied to record
  4334 constructor terms) are part of the standard simpset;
  4335 
  4336   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4337 made part of standard simpset and claset via addIffs;
  4338 
  4339   3) a tactic for record field splitting (record_split_tac) is part of
  4340 the standard claset (addSWrapper);
  4341 
  4342 To get a better idea about these rules you may retrieve them via
  4343 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4344 the name of your record type.
  4345 
  4346 The split tactic 3) conceptually simplifies by the following rule:
  4347 
  4348   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4349 
  4350 Thus any record variable that is bound by meta-all will automatically
  4351 blow up into some record constructor term, consequently the
  4352 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4353 solve record problems automatically.
  4354 
  4355 
  4356 * reorganized the main HOL image: HOL/Integ and String loaded by
  4357 default; theory Main includes everything;
  4358 
  4359 * automatic simplification of integer sums and comparisons, using cancellation;
  4360 
  4361 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4362 
  4363 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4364 
  4365 * many new identities for unions, intersections, set difference, etc.;
  4366 
  4367 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4368 called split_if, split_split, split_sum_case and split_nat_case (to go
  4369 with add/delsplits);
  4370 
  4371 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4372 (?x::unit) = (); this is made part of the default simpset, which COULD
  4373 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4374 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4375 unit_abs_eta_conv is added in order to counter the effect of
  4376 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4377 %u.f();
  4378 
  4379 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4380 makes more sense);
  4381 
  4382 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4383   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4384   disjointness reasoning but breaking a few old proofs.
  4385 
  4386 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4387 to 'converse' from 'inverse' (for compatibility with ZF and some
  4388 literature);
  4389 
  4390 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4391 the well-founded relation;
  4392 
  4393 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4394     Compl A.  The "Compl" syntax remains available as input syntax for this
  4395     release ONLY.
  4396 
  4397 * HOL/Update: new theory of function updates:
  4398     f(a:=b) == %x. if x=a then b else f x
  4399 may also be iterated as in f(a:=b,c:=d,...);
  4400 
  4401 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4402 
  4403 * HOL/List:
  4404   - new function list_update written xs[i:=v] that updates the i-th
  4405     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4406   - new function `upt' written [i..j(] which generates the list
  4407     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4408     bound write [i..j], which is a shorthand for [i..j+1(].
  4409   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4410 
  4411 * HOL/Arith:
  4412   - removed 'pred' (predecessor) function;
  4413   - generalized some theorems about n-1;
  4414   - many new laws about "div" and "mod";
  4415   - new laws about greatest common divisors (see theory ex/Primes);
  4416 
  4417 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4418 instead of "inverse";
  4419 
  4420 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4421   of the multiset ordering;
  4422 
  4423 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4424   (not included by default);
  4425 
  4426 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4427 
  4428 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4429   programs, i.e. different program variables may have different types.
  4430 
  4431 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4432   [previously, this check worked only if the rewrite rule was unconditional]
  4433   Now rew can involve either definitions or equalities (either == or =).
  4434 
  4435 
  4436 *** ZF ***
  4437 
  4438 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4439   only the theorems proved on ZF.ML;
  4440 
  4441 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4442   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4443   disjointness reasoning but breaking a few old proofs.
  4444 
  4445 * ZF/Update: new theory of function updates
  4446     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4447   may also be iterated as in f(a:=b,c:=d,...);
  4448 
  4449 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4450 
  4451 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4452   [previously, this check worked only if the rewrite rule was unconditional]
  4453   Now rew can involve either definitions or equalities (either == or =).
  4454 
  4455 * case_tac provided for compatibility with HOL
  4456     (like the old excluded_middle_tac, but with subgoals swapped)
  4457 
  4458 
  4459 *** Internal programming interfaces ***
  4460 
  4461 * Pure: several new basic modules made available for general use, see
  4462 also src/Pure/README;
  4463 
  4464 * improved the theory data mechanism to support encapsulation (data
  4465 kind name replaced by private Object.kind, acting as authorization
  4466 key); new type-safe user interface via functor TheoryDataFun; generic
  4467 print_data function becomes basically useless;
  4468 
  4469 * removed global_names compatibility flag -- all theory declarations
  4470 are qualified by default;
  4471 
  4472 * module Pure/Syntax now offers quote / antiquote translation
  4473 functions (useful for Hoare logic etc. with implicit dependencies);
  4474 see HOL/ex/Antiquote for an example use;
  4475 
  4476 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4477 cterm -> thm;
  4478 
  4479 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4480 subgoal;
  4481 
  4482 * Display.print_goals function moved to Locale.print_goals;
  4483 
  4484 * standard print function for goals supports current_goals_markers
  4485 variable for marking begin of proof, end of proof, start of goal; the
  4486 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4487 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4488 for example;
  4489 
  4490 
  4491 
  4492 New in Isabelle98 (January 1998)
  4493 --------------------------------
  4494 
  4495 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4496 
  4497 * changed lexical syntax of terms / types: dots made part of long
  4498 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4499 
  4500 * simpset (and claset) reference variable replaced by functions
  4501 simpset / simpset_ref;
  4502 
  4503 * no longer supports theory aliases (via merge) and non-trivial
  4504 implicit merge of thms' signatures;
  4505 
  4506 * most internal names of constants changed due to qualified names;
  4507 
  4508 * changed Pure/Sequence interface (see Pure/seq.ML);
  4509 
  4510 
  4511 *** General Changes ***
  4512 
  4513 * hierachically structured name spaces (for consts, types, axms, thms
  4514 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4515 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4516 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4517 long_names for fully qualified output names; NOTE: ML programs
  4518 (special tactics, packages etc.) referring to internal names may have
  4519 to be adapted to cope with fully qualified names; in case of severe
  4520 backward campatibility problems try setting 'global_names' at compile
  4521 time to have enrything declared within a flat name space; one may also
  4522 fine tune name declarations in theories via the 'global' and 'local'
  4523 section;
  4524 
  4525 * reimplemented the implicit simpset and claset using the new anytype
  4526 data filed in signatures; references simpset:simpset ref etc. are
  4527 replaced by functions simpset:unit->simpset and
  4528 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4529 to patch your ML files accordingly;
  4530 
  4531 * HTML output now includes theory graph data for display with Java
  4532 applet or isatool browser; data generated automatically via isatool
  4533 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4534 
  4535 * defs may now be conditional; improved rewrite_goals_tac to handle
  4536 conditional equations;
  4537 
  4538 * defs now admits additional type arguments, using TYPE('a) syntax;
  4539 
  4540 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4541 creates a new theory node; implicit merge of thms' signatures is
  4542 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4543 transfer:theory->thm->thm in (rare) cases;
  4544 
  4545 * improved handling of draft signatures / theories; draft thms (and
  4546 ctyps, cterms) are automatically promoted to real ones;
  4547 
  4548 * slightly changed interfaces for oracles: admit many per theory, named
  4549 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4550 
  4551 * print_goals: optional output of const types (set show_consts and
  4552 show_types);
  4553 
  4554 * improved output of warnings (###) and errors (***);
  4555 
  4556 * subgoal_tac displays a warning if the new subgoal has type variables;
  4557 
  4558 * removed old README and Makefiles;
  4559 
  4560 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4561 
  4562 * removed obsolete init_pps and init_database;
  4563 
  4564 * deleted the obsolete tactical STATE, which was declared by
  4565     fun STATE tacfun st = tacfun st st;
  4566 
  4567 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4568 (which abbreviates $HOME);
  4569 
  4570 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4571 use isatool fixseq to adapt your ML programs (this works for fully
  4572 qualified references to the Sequence structure only!);
  4573 
  4574 * use_thy no longer requires writable current directory; it always
  4575 reloads .ML *and* .thy file, if either one is out of date;
  4576 
  4577 
  4578 *** Classical Reasoner ***
  4579 
  4580 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4581 tactics that use classical reasoning to simplify a subgoal without
  4582 splitting it into several subgoals;
  4583 
  4584 * Safe_tac: like safe_tac but uses the default claset;
  4585 
  4586 
  4587 *** Simplifier ***
  4588 
  4589 * added simplification meta rules:
  4590     (asm_)(full_)simplify: simpset -> thm -> thm;
  4591 
  4592 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4593 logics (again);
  4594 
  4595 * added prems argument to simplification procedures;
  4596 
  4597 * HOL, FOL, ZF: added infix function `addsplits':
  4598   instead of `<simpset> setloop (split_tac <thms>)'
  4599   you can simply write `<simpset> addsplits <thms>'
  4600 
  4601 
  4602 *** Syntax ***
  4603 
  4604 * TYPE('a) syntax for type reflection terms;
  4605 
  4606 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4607 
  4608 * pretty printer: changed order of mixfix annotation preference (again!);
  4609 
  4610 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4611 
  4612 
  4613 *** HOL ***
  4614 
  4615 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4616   with `addloop' of the simplifier to faciliate case splitting in premises.
  4617 
  4618 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4619 
  4620 * HOL/Auth: new protocol proofs including some for the Internet
  4621   protocol TLS;
  4622 
  4623 * HOL/Map: new theory of `maps' a la VDM;
  4624 
  4625 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4626 cancelling out common nat summands from =, <, <= (in)equalities, or
  4627 differences; simplification procedures nat_cancel_factor for
  4628 cancelling common factor from =, <, <= (in)equalities over natural
  4629 sums; nat_cancel contains both kinds of procedures, it is installed by
  4630 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4631 
  4632 * HOL/simplifier: terms of the form
  4633   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4634   are rewritten to
  4635   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4636   and those of the form
  4637   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4638   are rewritten to
  4639   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4640 
  4641 * HOL/datatype
  4642   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4643 
  4644   P(t_case f1 ... fn x) =
  4645      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4646         ...
  4647        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4648      )
  4649 
  4650   and a theorem `split_t_case_asm' of the form
  4651 
  4652   P(t_case f1 ... fn x) =
  4653     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4654         ...
  4655        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4656      )
  4657   which can be added to a simpset via `addsplits'. The existing theorems
  4658   expand_list_case and expand_option_case have been renamed to
  4659   split_list_case and split_option_case.
  4660 
  4661 * HOL/Arithmetic:
  4662   - `pred n' is automatically converted to `n-1'.
  4663     Users are strongly encouraged not to use `pred' any longer,
  4664     because it will disappear altogether at some point.
  4665   - Users are strongly encouraged to write "0 < n" rather than
  4666     "n ~= 0". Theorems and proof tools have been modified towards this
  4667     `standard'.
  4668 
  4669 * HOL/Lists:
  4670   the function "set_of_list" has been renamed "set" (and its theorems too);
  4671   the function "nth" now takes its arguments in the reverse order and
  4672   has acquired the infix notation "!" as in "xs!n".
  4673 
  4674 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4675 
  4676 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4677   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4678 
  4679 * HOL/record: extensible records with schematic structural subtyping
  4680 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4681 still lacks various theorems and concrete record syntax;
  4682 
  4683 
  4684 *** HOLCF ***
  4685 
  4686 * removed "axioms" and "generated by" sections;
  4687 
  4688 * replaced "ops" section by extended "consts" section, which is capable of
  4689   handling the continuous function space "->" directly;
  4690 
  4691 * domain package:
  4692   . proves theorems immediately and stores them in the theory,
  4693   . creates hierachical name space,
  4694   . now uses normal mixfix annotations (instead of cinfix...),
  4695   . minor changes to some names and values (for consistency),
  4696   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4697   . separator between mutual domain defs: changed "," to "and",
  4698   . improved handling of sort constraints;  now they have to
  4699     appear on the left-hand side of the equations only;
  4700 
  4701 * fixed LAM <x,y,zs>.b syntax;
  4702 
  4703 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4704 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4705 
  4706 
  4707 *** FOL and ZF ***
  4708 
  4709 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4710   with `addloop' of the simplifier to faciliate case splitting in premises.
  4711 
  4712 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4713 in HOL, they strip ALL and --> from proved theorems;
  4714 
  4715 
  4716 
  4717 New in Isabelle94-8 (May 1997)
  4718 ------------------------------
  4719 
  4720 *** General Changes ***
  4721 
  4722 * new utilities to build / run / maintain Isabelle etc. (in parts
  4723 still somewhat experimental); old Makefiles etc. still functional;
  4724 
  4725 * new 'Isabelle System Manual';
  4726 
  4727 * INSTALL text, together with ./configure and ./build scripts;
  4728 
  4729 * reimplemented type inference for greater efficiency, better error
  4730 messages and clean internal interface;
  4731 
  4732 * prlim command for dealing with lots of subgoals (an easier way of
  4733 setting goals_limit);
  4734 
  4735 
  4736 *** Syntax ***
  4737 
  4738 * supports alternative (named) syntax tables (parser and pretty
  4739 printer); internal interface is provided by add_modesyntax(_i);
  4740 
  4741 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4742 be used in conjunction with the Isabelle symbol font; uses the
  4743 "symbols" syntax table;
  4744 
  4745 * added token_translation interface (may translate name tokens in
  4746 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4747 the current print_mode); IMPORTANT: user print translation functions
  4748 are responsible for marking newly introduced bounds
  4749 (Syntax.mark_boundT);
  4750 
  4751 * token translations for modes "xterm" and "xterm_color" that display
  4752 names in bold, underline etc. or colors (which requires a color
  4753 version of xterm);
  4754 
  4755 * infixes may now be declared with names independent of their syntax;
  4756 
  4757 * added typed_print_translation (like print_translation, but may
  4758 access type of constant);
  4759 
  4760 
  4761 *** Classical Reasoner ***
  4762 
  4763 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4764 some limitations.  Blast_tac...
  4765   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4766   + ignores elimination rules that don't have the correct format
  4767         (the conclusion MUST be a formula variable)
  4768   + ignores types, which can make HOL proofs fail
  4769   + rules must not require higher-order unification, e.g. apply_type in ZF
  4770     [message "Function Var's argument not a bound variable" relates to this]
  4771   + its proof strategy is more general but can actually be slower
  4772 
  4773 * substitution with equality assumptions no longer permutes other
  4774 assumptions;
  4775 
  4776 * minor changes in semantics of addafter (now called addaltern); renamed
  4777 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4778 (and access functions for it);
  4779 
  4780 * improved combination of classical reasoner and simplifier:
  4781   + functions for handling clasimpsets
  4782   + improvement of addss: now the simplifier is called _after_ the
  4783     safe steps.
  4784   + safe variant of addss called addSss: uses safe simplifications
  4785     _during_ the safe steps. It is more complete as it allows multiple
  4786     instantiations of unknowns (e.g. with slow_tac).
  4787 
  4788 *** Simplifier ***
  4789 
  4790 * added interface for simplification procedures (functions that
  4791 produce *proven* rewrite rules on the fly, depending on current
  4792 redex);
  4793 
  4794 * ordering on terms as parameter (used for ordered rewriting);
  4795 
  4796 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4797 
  4798 * the solver is now split into a safe and an unsafe part.
  4799 This should be invisible for the normal user, except that the
  4800 functions setsolver and addsolver have been renamed to setSolver and
  4801 addSolver; added safe_asm_full_simp_tac;
  4802 
  4803 
  4804 *** HOL ***
  4805 
  4806 * a generic induction tactic `induct_tac' which works for all datatypes and
  4807 also for type `nat';
  4808 
  4809 * a generic case distinction tactic `exhaust_tac' which works for all
  4810 datatypes and also for type `nat';
  4811 
  4812 * each datatype comes with a function `size';
  4813 
  4814 * patterns in case expressions allow tuple patterns as arguments to
  4815 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4816 
  4817 * primrec now also works with type nat;
  4818 
  4819 * recdef: a new declaration form, allows general recursive functions to be
  4820 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4821 
  4822 * the constant for negation has been renamed from "not" to "Not" to
  4823 harmonize with FOL, ZF, LK, etc.;
  4824 
  4825 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4826 infinite lists;
  4827 
  4828 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4829 
  4830 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4831 problems in commutative rings, using axiomatic type classes for + and *;
  4832 
  4833 * more examples in HOL/MiniML and HOL/Auth;
  4834 
  4835 * more default rewrite rules for quantifiers, union/intersection;
  4836 
  4837 * a new constant `arbitrary == @x.False';
  4838 
  4839 * HOLCF/IOA replaces old HOL/IOA;
  4840 
  4841 * HOLCF changes: derived all rules and arities
  4842   + axiomatic type classes instead of classes
  4843   + typedef instead of faking type definitions
  4844   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4845   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4846   + eliminated the types void, one, tr
  4847   + use unit lift and bool lift (with translations) instead of one and tr
  4848   + eliminated blift from Lift3.thy (use Def instead of blift)
  4849   all eliminated rules are derived as theorems --> no visible changes ;
  4850 
  4851 
  4852 *** ZF ***
  4853 
  4854 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4855 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4856 as ZF_cs addSIs [equalityI];
  4857 
  4858 
  4859 
  4860 New in Isabelle94-7 (November 96)
  4861 ---------------------------------
  4862 
  4863 * allowing negative levels (as offsets) in prlev and choplev;
  4864 
  4865 * super-linear speedup for large simplifications;
  4866 
  4867 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4868 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4869 FAIL); can suppress it using the command Delsimps (ex_simps @
  4870 all_simps); De Morgan laws are also now included, by default;
  4871 
  4872 * improved printing of ==>  :  ~:
  4873 
  4874 * new object-logic "Sequents" adds linear logic, while replacing LK
  4875 and Modal (thanks to Sara Kalvala);
  4876 
  4877 * HOL/Auth: correctness proofs for authentication protocols;
  4878 
  4879 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4880 examples on HOL/Auth);
  4881 
  4882 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4883 the rewriter and classical reasoner simultaneously;
  4884 
  4885 * function uresult no longer returns theorems in "standard" format;
  4886 regain previous version by: val uresult = standard o uresult;
  4887 
  4888 
  4889 
  4890 New in Isabelle94-6
  4891 -------------------
  4892 
  4893 * oracles -- these establish an interface between Isabelle and trusted
  4894 external reasoners, which may deliver results as theorems;
  4895 
  4896 * proof objects (in particular record all uses of oracles);
  4897 
  4898 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4899 
  4900 * "constdefs" section in theory files;
  4901 
  4902 * "primrec" section (HOL) no longer requires names;
  4903 
  4904 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4905 
  4906 
  4907 
  4908 New in Isabelle94-5
  4909 -------------------
  4910 
  4911 * reduced space requirements;
  4912 
  4913 * automatic HTML generation from theories;
  4914 
  4915 * theory files no longer require "..." (quotes) around most types;
  4916 
  4917 * new examples, including two proofs of the Church-Rosser theorem;
  4918 
  4919 * non-curried (1994) version of HOL is no longer distributed;
  4920 
  4921 
  4922 
  4923 New in Isabelle94-4
  4924 -------------------
  4925 
  4926 * greatly reduced space requirements;
  4927 
  4928 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4929 
  4930 * searchable theorem database (see the section "Retrieving theorems" on
  4931 page 8 of the Reference Manual);
  4932 
  4933 * new examples, including Grabczewski's monumental case study of the
  4934 Axiom of Choice;
  4935 
  4936 * The previous version of HOL renamed to Old_HOL;
  4937 
  4938 * The new version of HOL (previously called CHOL) uses a curried syntax
  4939 for functions.  Application looks like f a b instead of f(a,b);
  4940 
  4941 * Mutually recursive inductive definitions finally work in HOL;
  4942 
  4943 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4944 translates to the operator "split";
  4945 
  4946 
  4947 
  4948 New in Isabelle94-3
  4949 -------------------
  4950 
  4951 * new infix operator, addss, allowing the classical reasoner to
  4952 perform simplification at each step of its search.  Example:
  4953         fast_tac (cs addss ss)
  4954 
  4955 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4956 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4957 look like (a,b) instead of <a,b>;
  4958 
  4959 * PLEASE NOTE: CHOL will eventually replace HOL!
  4960 
  4961 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4962 It translates to the operator "split".  A new theory of integers is available;
  4963 
  4964 * In ZF, integer numerals now denote two's-complement binary integers.
  4965 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4966 
  4967 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4968 of the Axiom of Choice;
  4969 
  4970 
  4971 
  4972 New in Isabelle94-2
  4973 -------------------
  4974 
  4975 * Significantly faster resolution;
  4976 
  4977 * the different sections in a .thy file can now be mixed and repeated
  4978 freely;
  4979 
  4980 * Database of theorems for FOL, HOL and ZF.  New
  4981 commands including qed, qed_goal and bind_thm store theorems in the database.
  4982 
  4983 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4984 a given theory (thms_of), or find out what theory a theorem was proved in
  4985 (theory_of_thm);
  4986 
  4987 * Bugs fixed in the inductive definition and datatype packages;
  4988 
  4989 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4990 and HOL_dup_cs obsolete;
  4991 
  4992 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4993 have been removed;
  4994 
  4995 * Simpler definition of function space in ZF;
  4996 
  4997 * new results about cardinal and ordinal arithmetic in ZF;
  4998 
  4999 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5000 types;
  5001 
  5002 :mode=text:wrap=hard:maxLineLen=72:
  5003 $Id$