NEWS
author nipkow
Mon Sep 24 19:34:55 2007 +0200 (2007-09-24)
changeset 24691 e7f46ee04809
parent 24649 f7b68d12a91e
child 24692 a5d89a87e8e3
permissions -rw-r--r--
localized { .. } (but only a few thms)
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
    12 legacy features will disappear eventually.
    13 
    14 * Theory syntax: the header format ``theory A = B + C:'' has been
    15 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    16 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: the old non-Isar theory file format has been
    19 discontinued altogether.  Note that ML proof scripts may still be used
    20 with Isar theories; migration is usually quite simple with the ML
    21 function use_legacy_bindings.  INCOMPATIBILITY.
    22 
    23 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    24 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    25 quotes.
    26 
    27 * Theory loader: be more serious about observing the static theory
    28 header specifications (including optional directories), but not the
    29 accidental file locations of previously successful loads.  The strict
    30 update policy of former update_thy is now already performed by
    31 use_thy, so the former has been removed; use_thys updates several
    32 theories simultaneously, just as 'imports' within a theory header
    33 specification, but without merging the results.  Potential
    34 INCOMPATIBILITY: may need to refine theory headers and commands
    35 ROOT.ML which depend on load order.
    36 
    37 * Theory loader: optional support for content-based file
    38 identification, instead of the traditional scheme of full physical
    39 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    40 (cf. the system manual).  The new scheme allows to work with
    41 non-finished theories in persistent session images, such that source
    42 files may be moved later on without requiring reloads.
    43 
    44 * Theory loader: old-style ML proof scripts being *attached* to a thy
    45 file (with the same base name as the theory) are considered a legacy
    46 feature, which will disappear eventually. Even now, the theory loader no
    47 longer maintains dependencies on such files.
    48 
    49 * Syntax: the scope for resolving ambiguities via type-inference is now
    50 limited to individual terms, instead of whole simultaneous
    51 specifications as before. This greatly reduces the complexity of the
    52 syntax module and improves flexibility by separating parsing and
    53 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
    54 'fixes' etc.) are required in rare situations.
    55 
    56 * Legacy goal package: reduced interface to the bare minimum required
    57 to keep existing proof scripts running.  Most other user-level
    58 functions are now part of the OldGoals structure, which is *not* open
    59 by default (consider isatool expandshort before open OldGoals).
    60 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    61 these tend to cause confusion about the actual goal (!) context being
    62 used here, which is not necessarily the same as the_context().
    63 
    64 * Command 'find_theorems': supports "*" wild-card in "name:"
    65 criterion; "with_dups" option.  Certain ProofGeneral versions might
    66 support a specific search form (see ProofGeneral/CHANGES).
    67 
    68 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    69 by default, which means that "prems" (and also "fixed variables") are
    70 suppressed from proof state output.  Note that the ProofGeneral
    71 settings mechanism allows to change and save options persistently, but
    72 older versions of Isabelle will fail to start up if a negative prems
    73 limit is imposed.
    74 
    75 * Local theory targets may be specified by non-nested blocks of
    76 ``context/locale/class ... begin'' followed by ``end''.  The body may
    77 contain definitions, theorems etc., including any derived mechanism
    78 that has been implemented on top of these primitives.  This concept
    79 generalizes the existing ``theorem (in ...)'' towards more versatility
    80 and scalability.
    81 
    82 * Proof General interface: proper undo of final 'end' command;
    83 discontinued Isabelle/classic mode (ML proof scripts).
    84 
    85 
    86 *** Document preparation ***
    87 
    88 * Added antiquotation @{theory name} which prints the given name,
    89 after checking that it refers to a valid ancestor theory in the
    90 current context.
    91 
    92 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    93 check the given source text as ML type/structure, printing verbatim.
    94 
    95 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    96 "c args == rhs" given in the current context.  (Any number of
    97 arguments may be given on the LHS.)
    98 
    99 
   100 
   101 *** Pure ***
   102 
   103 * code generator: consts in 'consts_code' Isar commands are now referred
   104   to by usual term syntax (including optional type annotations).
   105 
   106 * code generator: 
   107   - Isar 'definition's, 'constdef's and primitive instance definitions are added
   108     explicitly to the table of defining equations
   109   - primitive definitions are not used as defining equations by default any longer
   110   - defining equations are now definitly restricted to meta "==" and object
   111         equality "="
   112   - HOL theories have been adopted accordingly
   113 
   114 * class_package.ML offers a combination of axclasses and locales to
   115 achieve Haskell-like type classes in Isabelle.  See
   116 HOL/ex/Classpackage.thy for examples.
   117 
   118 * Yet another code generator framework allows to generate executable
   119 code for ML and Haskell (including "class"es).  A short usage sketch:
   120 
   121     internal compilation:
   122         code_gen <list of constants (term syntax)> in SML
   123     writing SML code to a file:
   124         code_gen <list of constants (term syntax)> in SML <filename>
   125     writing OCaml code to a file:
   126         code_gen <list of constants (term syntax)> in OCaml <filename>
   127     writing Haskell code to a bunch of files:
   128         code_gen <list of constants (term syntax)> in Haskell <filename>
   129 
   130 Reasonable default setup of framework in HOL/Main.
   131 
   132 Theorem attributs for selecting and transforming function equations theorems:
   133 
   134     [code fun]:        select a theorem as function equation for a specific constant
   135     [code fun del]:    deselect a theorem as function equation for a specific constant
   136     [code inline]:     select an equation theorem for unfolding (inlining) in place
   137     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   138 
   139 User-defined serializations (target in {SML, OCaml, Haskell}):
   140 
   141     code_const <and-list of constants (term syntax)>
   142       {(target) <and-list of const target syntax>}+
   143 
   144     code_type <and-list of type constructors>
   145       {(target) <and-list of type target syntax>}+
   146 
   147     code_instance <and-list of instances>
   148       {(target)}+
   149         where instance ::= <type constructor> :: <class>
   150 
   151     code_class <and_list of classes>
   152       {(target) <and-list of class target syntax>}+
   153         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   154 
   155 code_instance and code_class only apply to target Haskell.
   156 
   157 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   158 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   159 
   160 * Command 'no_translations' removes translation rules from theory
   161 syntax.
   162 
   163 * Overloaded definitions are now actually checked for acyclic
   164 dependencies.  The overloading scheme is slightly more general than
   165 that of Haskell98, although Isabelle does not demand an exact
   166 correspondence to type class and instance declarations.
   167 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   168 exotic versions of overloading -- at the discretion of the user!
   169 
   170 Polymorphic constants are represented via type arguments, i.e. the
   171 instantiation that matches an instance against the most general
   172 declaration given in the signature.  For example, with the declaration
   173 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   174 as c(nat).  Overloading is essentially simultaneous structural
   175 recursion over such type arguments.  Incomplete specification patterns
   176 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   177 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   178 Command 'print_theory' outputs the normalized system of recursive
   179 equations, see section "definitions".
   180 
   181 * Configuration options are maintained within the theory or proof
   182 context (with name and type bool/int/string), providing a very simple
   183 interface to a poor-man's version of general context data.  Tools may
   184 declare options in ML (e.g. using Attrib.config_int) and then refer to
   185 these values using Config.get etc.  Users may change options via an
   186 associated attribute of the same name.  This form of context
   187 declaration works particularly well with commands 'declare' or
   188 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   189 very easy to avoid global references, which would not observe Isar
   190 toplevel undo/redo and fail to work with multithreading.
   191 
   192 Various global ML references of Pure and HOL have been turned into
   193 configuration options:
   194 
   195   Unify.search_bound		unify_search_bound
   196   Unify.trace_bound		unify_trace_bound
   197   Unify.trace_simp		unify_trace_simp
   198   Unify.trace_types		unify_trace_types
   199   Simplifier.simp_depth_limit	simp_depth_limit
   200   Blast.depth_limit		blast_depth_limit
   201   DatatypeProp.dtK		datatype_distinctness_limit
   202   fast_arith_neq_limit  	fast_arith_neq_limit
   203   fast_arith_split_limit	fast_arith_split_limit
   204 
   205 * Named collections of theorems may be easily installed as context
   206 data using the functor NamedThmsFun (see
   207 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   208 attributes; there is also a toplevel print command.  This facility is
   209 just a common case of general context data, which is the preferred way
   210 for anything more complex than just a list of facts in canonical
   211 order.
   212 
   213 * Isar: command 'declaration' augments a local theory by generic
   214 declaration functions written in ML.  This enables arbitrary content
   215 being added to the context, depending on a morphism that tells the
   216 difference of the original declaration context wrt. the application
   217 context encountered later on.
   218 
   219 * Isar: proper interfaces for simplification procedures.  Command
   220 'simproc_setup' declares named simprocs (with match patterns, and body
   221 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   222 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   223 
   224 * Isar: an extra pair of brackets around attribute declarations
   225 abbreviates a theorem reference involving an internal dummy fact,
   226 which will be ignored later --- only the effect of the attribute on
   227 the background context will persist.  This form of in-place
   228 declarations is particularly useful with commands like 'declare' and
   229 'using', for example ``have A using [[simproc a]] by simp''.
   230 
   231 * Isar: method "assumption" (and implicit closing of subproofs) now
   232 takes simple non-atomic goal assumptions into account: after applying
   233 an assumption as a rule the resulting subgoals are solved by atomic
   234 assumption steps.  This is particularly useful to finish 'obtain'
   235 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   236 without referring to the original premise "!!x. P x ==> thesis" in the
   237 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   238 more permissive.
   239 
   240 * Isar: implicit use of prems from the Isar proof context is
   241 considered a legacy feature.  Common applications like ``have A .''
   242 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   243 referencing facts explicitly here improves readability and
   244 maintainability of proof texts.
   245 
   246 * Isar: improper proof element 'guess' is like 'obtain', but derives
   247 the obtained context from the course of reasoning!  For example:
   248 
   249   assume "EX x y. A x & B y"   -- "any previous fact"
   250   then guess x and y by clarify
   251 
   252 This technique is potentially adventurous, depending on the facts and
   253 proof tools being involved here.
   254 
   255 * Isar: known facts from the proof context may be specified as literal
   256 propositions, using ASCII back-quote syntax.  This works wherever
   257 named facts used to be allowed so far, in proof commands, proof
   258 methods, attributes etc.  Literal facts are retrieved from the context
   259 according to unification of type and term parameters.  For example,
   260 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   261 theorems in the current context, then these are valid literal facts:
   262 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   263 
   264 There is also a proof method "fact" which does the same composition
   265 for explicit goal states, e.g. the following proof texts coincide with
   266 certain special cases of literal facts:
   267 
   268   have "A" by fact                 ==  note `A`
   269   have "A ==> B" by fact           ==  note `A ==> B`
   270   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   271   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   272 
   273 * Isar: ":" (colon) is no longer a symbolic identifier character in
   274 outer syntax.  Thus symbolic identifiers may be used without
   275 additional white space in declarations like this: ``assume *: A''.
   276 
   277 * Isar: 'print_facts' prints all local facts of the current context,
   278 both named and unnamed ones.
   279 
   280 * Isar: 'def' now admits simultaneous definitions, e.g.:
   281 
   282   def x == "t" and y == "u"
   283 
   284 * Isar: added command 'unfolding', which is structurally similar to
   285 'using', but affects both the goal state and facts by unfolding given
   286 rewrite rules.  Thus many occurrences of the 'unfold' method or
   287 'unfolded' attribute may be replaced by first-class proof text.
   288 
   289 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   290 and command 'unfolding' now all support object-level equalities
   291 (potentially conditional).  The underlying notion of rewrite rule is
   292 analogous to the 'rule_format' attribute, but *not* that of the
   293 Simplifier (which is usually more generous).
   294 
   295 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   296 premises of a theorem by n. Useful in conjunction with drule.
   297 
   298 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   299 method expression within a sandbox consisting of the first N
   300 sub-goals, which need to exist.  For example, ``simp_all [3]''
   301 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   302 simplifies all new goals that emerge from applying rule foo to the
   303 originally first one.
   304 
   305 * Isar: schematic goals are no longer restricted to higher-order
   306 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   307 expected.
   308 
   309 * Isar: the conclusion of a long theorem statement is now either
   310 'shows' (a simultaneous conjunction, as before), or 'obtains'
   311 (essentially a disjunction of cases with local parameters and
   312 assumptions).  The latter allows to express general elimination rules
   313 adequately; in this notation common elimination rules look like this:
   314 
   315   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   316     assumes "EX x. P x"
   317     obtains x where "P x"
   318 
   319   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   320     assumes "A & B"
   321     obtains A and B
   322 
   323   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   324     assumes "A | B"
   325     obtains
   326       A
   327     | B
   328 
   329 The subsequent classical rules even refer to the formal "thesis"
   330 explicitly:
   331 
   332   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   333     obtains "~ thesis"
   334 
   335   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   336     obtains "thesis ==> something"
   337 
   338 The actual proof of an 'obtains' statement is analogous to that of the
   339 Isar proof element 'obtain', only that there may be several cases.
   340 Optional case names may be specified in parentheses; these will be
   341 available both in the present proof and as annotations in the
   342 resulting rule, for later use with the 'cases' method (cf. attribute
   343 case_names).
   344 
   345 * Isar: the assumptions of a long theorem statement are available as
   346 "assms" fact in the proof context.  This is more appropriate than the
   347 (historical) "prems", which refers to all assumptions of the current
   348 context, including those from the target locale, proof body etc.
   349 
   350 * Isar: 'print_statement' prints theorems from the current theory or
   351 proof context in long statement form, according to the syntax of a
   352 top-level lemma.
   353 
   354 * Isar: 'obtain' takes an optional case name for the local context
   355 introduction rule (default "that").
   356 
   357 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   358 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   359 to occur.
   360 
   361 * Pure: syntax "CONST name" produces a fully internalized constant
   362 according to the current context.  This is particularly useful for
   363 syntax translations that should refer to internal constant
   364 representations independently of name spaces.
   365 
   366 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   367 instead of "FOO ". This allows multiple binder declarations to coexist
   368 in the same context.  INCOMPATIBILITY.
   369 
   370 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   371 primitive that also works in a locale context (both for constants and
   372 fixed variables).  Type declaration and internal syntactic
   373 representation of given constants retrieved from the context.
   374 
   375 * Isar/locales: new derived specification elements 'axiomatization',
   376 'definition', 'abbreviation', which support type-inference, admit
   377 object-level specifications (equality, equivalence).  See also the
   378 isar-ref manual.  Examples:
   379 
   380   axiomatization
   381     eq  (infix "===" 50) where
   382     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   383 
   384   definition "f x y = x + y + 1"
   385   definition g where "g x = f x x"
   386 
   387   abbreviation
   388     neq  (infix "=!=" 50) where
   389     "x =!= y == ~ (x === y)"
   390 
   391 These specifications may be also used in a locale context.  Then the
   392 constants being introduced depend on certain fixed parameters, and the
   393 constant name is qualified by the locale base name.  An internal
   394 abbreviation takes care for convenient input and output, making the
   395 parameters implicit and using the original short name.  See also
   396 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   397 entities from a monomorphic theory.
   398 
   399 Presently, abbreviations are only available 'in' a target locale, but
   400 not inherited by general import expressions.  Also note that
   401 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   402 'translations' in common applications.
   403 
   404 Concrete syntax is attached to specified constants in internal form,
   405 independently of name spaces.  The parse tree representation is
   406 slightly different -- use 'notation' instead of raw 'syntax', and
   407 'translations' with explicit "CONST" markup to accommodate this.
   408 
   409 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   410 the current context.  Print mode "no_abbrevs" prevents inversion of
   411 abbreviations on output.
   412 
   413 * Isar/locales: improved parameter handling:
   414 - use of locales "var" and "struct" no longer necessary;
   415 - parameter renamings are no longer required to be injective.
   416   This enables, for example, to define a locale for endomorphisms thus:
   417   locale endom = homom mult mult h.
   418 
   419 * Isar/locales: changed the way locales with predicates are defined.
   420 Instead of accumulating the specification, the imported expression is
   421 now an interpretation.  INCOMPATIBILITY: different normal form of
   422 locale expressions.  In particular, in interpretations of locales with
   423 predicates, goals repesenting already interpreted fragments are not
   424 removed automatically.  Use methods `intro_locales' and
   425 `unfold_locales'; see below.
   426 
   427 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   428 provide backward reasoning on locales predicates.  The methods are
   429 aware of interpretations and discharge corresponding goals.
   430 `intro_locales' is less aggressive then `unfold_locales' and does not
   431 unfold predicates to assumptions.
   432 
   433 * Isar/locales: the order in which locale fragments are accumulated
   434 has changed.  This enables to override declarations from fragments due
   435 to interpretations -- for example, unwanted simp rules.
   436 
   437 * Isar/locales: interpretation in theories and proof contexts has been
   438 extended.  One may now specify (and prove) equations, which are
   439 unfolded in interpreted theorems.  This is useful for replacing
   440 defined concepts (constants depending on locale parameters) by
   441 concepts already existing in the target context.  Example:
   442 
   443   interpretation partial_order ["op <= :: [int, int] => bool"]
   444     where "partial_order.less (op <=) (x::int) y = (x < y)"
   445 
   446 Typically, the constant `partial_order.less' is created by a definition
   447 specification element in the context of locale partial_order.
   448 
   449 * Provers/induct: improved internal context management to support local
   450 fixes and defines on-the-fly. Thus explicit meta-level connectives !!
   451 and ==> are rarely required anymore in inductive goals (using
   452 object-logic connectives for this purpose has been long obsolete
   453 anyway). Common proof patterns are explained in
   454 HOL/Induct/Common_Patterns.thy, see also HOL/Isar_examples/Puzzle.thy
   455 and src/HOL/Lambda for realistic examples.
   456 
   457 * Provers/induct: improved handling of simultaneous goals. Instead of
   458 introducing object-level conjunction, the statement is now split into
   459 several conclusions, while the corresponding symbolic cases are nested
   460 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   461 see HOL/Induct/Common_Patterns.thy, for example.
   462 
   463 * Provers/induct: mutual induction rules are now specified as a list of
   464 rule sharing the same induction cases. HOL packages usually provide
   465 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   466 sets or datatypes). INCOMPATIBILITY, users need to specify mutual
   467 induction rules differently, i.e. like this:
   468 
   469   (induct rule: foo_bar.inducts)
   470   (induct set: foo bar)
   471   (induct type: foo bar)
   472 
   473 The ML function ProjectRule.projections turns old-style rules into the
   474 new format.
   475 
   476 * Provers/induct: support coinduction as well. See
   477 src/HOL/Library/Coinductive_List.thy for various examples.
   478 
   479 * Attribute "symmetric" produces result with standardized schematic
   480 variables (index 0).  Potential INCOMPATIBILITY.
   481 
   482 * Simplifier: by default the simplifier trace only shows top level
   483 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   484 default. Thus there is less danger of being flooded by the trace. The
   485 trace indicates where parts have been suppressed.
   486   
   487 * Provers/classical: removed obsolete classical version of elim_format
   488 attribute; classical elim/dest rules are now treated uniformly when
   489 manipulating the claset.
   490 
   491 * Provers/classical: stricter checks to ensure that supplied intro,
   492 dest and elim rules are well-formed; dest and elim rules must have at
   493 least one premise.
   494 
   495 * Provers/classical: attributes dest/elim/intro take an optional
   496 weight argument for the rule (just as the Pure versions).  Weights are
   497 ignored by automated tools, but determine the search order of single
   498 rule steps.
   499 
   500 * Syntax: input syntax now supports dummy variable binding "%_. b",
   501 where the body does not mention the bound variable.  Note that dummy
   502 patterns implicitly depend on their context of bounds, which makes
   503 "{_. _}" match any set comprehension as expected.  Potential
   504 INCOMPATIBILITY -- parse translations need to cope with syntactic
   505 constant "_idtdummy" in the binding position.
   506 
   507 * Syntax: removed obsolete syntactic constant "_K" and its associated
   508 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   509 for example "A -> B" => "Pi A (%_. B)".
   510 
   511 * Pure: 'class_deps' command visualizes the subclass relation, using
   512 the graph browser tool.
   513 
   514 * Pure: 'print_theory' now suppresses entities with internal name
   515 (trailing "_") by default; use '!' option for full details.
   516 
   517 
   518 *** HOL ***
   519 
   520 * The transitivity reasoner for partial and linear orders is set up for
   521 locales `order' and `linorder' generated by the new class package.  Previously
   522 the reasoner was only set up for axiomatic type classes.  Instances of the
   523 reasoner are available in all contexts importing or interpreting these locales.
   524 The following functionality is provided:
   525   - method `order' to invoke the reasoner manually.
   526   - diagnostic command `print_orders' shows which instances of the reasoner are
   527     available in the current context.
   528 As previously, the reasoner is integrated with the simplifier as a solver. 
   529 
   530 * Formulation of theorem "dense" changed slightly due to integration with new
   531 class dense_linear_order.
   532 
   533 * theory Finite_Set: "name-space" locales Lattice, Distrib_lattice, Linorder etc.
   534 have disappeared; operations defined in terms of fold_set now are named
   535 Inf_fin, Sup_fin.  INCOMPATIBILITY.
   536 
   537 * HOL-Word:
   538   New extensive library and type for generic, fixed size machine
   539   words, with arithemtic, bit-wise, shifting and rotating operations,
   540   reflection into int, nat, and bool lists, automation for linear
   541   arithmetic (by automatic reflection into nat or int), including
   542   lemmas on overflow and monotonicity. Instantiated to all appropriate
   543   arithmetic type classes, supporting automatic simplification of
   544   numerals on all operations. Jointly developed by NICTA, Galois, and
   545   PSU.
   546 
   547 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   548 
   549 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   550 
   551 * Code generator library theories:
   552   * Pretty_Int represents HOL integers by big integer literals in target
   553     languages.
   554   * Pretty_Char represents HOL characters by character literals in target
   555     languages.
   556   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   557     codes; includes Pretty_Int.
   558   * Executable_Set allows to generate code for finite sets using lists.
   559   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   560     denominator).
   561   * Executable_Real implements a subset of real numbers, namly those
   562     representable by rational numbers.
   563   * Efficient_Nat implements natural numbers by integers, which in general will
   564     result in higher efficency; pattern matching with 0/Suc is eliminated;
   565     includes Pretty_Int.
   566   * ML_String provides an additional datatype ml_string; in the HOL default
   567     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   568     of type ml_string are mapped to strings in SML.
   569   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   570     built-in integers.
   571 
   572 * New package for inductive predicates
   573 
   574   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   575 
   576     inductive
   577       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   578       for z_1 :: U_1 and ... and z_n :: U_m
   579     where
   580       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   581     | ...
   582 
   583   rather than
   584 
   585     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   586 
   587     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   588     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   589 
   590     inductive "s z_1 ... z_m"
   591     intros
   592       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   593       ...
   594 
   595   For backward compatibility, there is a wrapper allowing inductive
   596   sets to be defined with the new package via
   597 
   598     inductive_set
   599       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   600       for z_1 :: U_1 and ... and z_n :: U_m
   601     where
   602       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   603     | ...
   604 
   605   or
   606 
   607     inductive_set
   608       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   609       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   610       for z_1 :: U_1 and ... and z_n :: U_m
   611     where
   612       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   613     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   614     | ...
   615 
   616   if the additional syntax "p ..." is required.
   617 
   618   Many examples can be found in the subdirectories Auth, Bali, Induct,
   619   or MicroJava.
   620 
   621   INCOMPATIBILITIES:
   622 
   623   - Since declaration and definition of inductive sets or predicates
   624     is no longer separated, abbreviations involving the newly introduced
   625     sets or predicates must be specified together with the introduction
   626     rules after the "where" keyword (see example above), rather than before
   627     the actual inductive definition.
   628 
   629   - The variables in induction and elimination rules are now quantified
   630     in the order of their occurrence in the introduction rules, rather than
   631     in alphabetical order. Since this may break some proofs, these proofs
   632     either have to be repaired, e.g. by reordering the variables
   633     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   634 
   635       case (rule_i a_i_1 ... a_i_{k_i})
   636 
   637     or the old order of quantification has to be restored by explicitly adding
   638     meta-level quantifiers in the introduction rules, i.e.
   639 
   640       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   641 
   642   - The format of the elimination rules is now
   643 
   644       p z_1 ... z_m x_1 ... x_n ==>
   645         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   646         ==> ... ==> P
   647 
   648     for predicates and
   649 
   650       (x_1, ..., x_n) : s z_1 ... z_m ==>
   651         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   652         ==> ... ==> P
   653 
   654     for sets rather than
   655 
   656       x : s z_1 ... z_m ==>
   657         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   658         ==> ... ==> P
   659 
   660     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   661     or simplification with the split_paired_all rule) before the above elimination
   662     rule is applicable.
   663 
   664   - The elimination or case analysis rules for (mutually) inductive sets or
   665     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   666     "p_1_..._p_k.elims" is no longer available.
   667 
   668 * Method "metis" proves goals by applying the Metis general-purpose
   669 resolution prover.  Examples are in the directory MetisExamples.  See
   670 also http://gilith.com/software/metis/
   671   
   672 * Command 'sledgehammer' invokes external automatic theorem provers as
   673 background processes.  It generates calls to the "metis" method if
   674 successful. These can be pasted into the proof.  Users do not have to
   675 wait for the automatic provers to return.
   676 
   677 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   678   take their order into account, like in functional programming.
   679   Internally, this is translated into nested case-expressions; missing cases
   680   are added and mapped to the predefined constant "undefined". In complicated
   681   cases printing may no longer show the original input but the internal
   682   form. Lambda-abstractions allow the same form of pattern matching:
   683   "% pat1 => e1 | ..." is an abbreviation for
   684   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   685 
   686 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   687   is an abbreviation for "of_nat :: nat => int". The simplification rules
   688   for "of_nat" have been changed to work like "int" did previously.
   689   (potential INCOMPATIBILITY)
   690   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   691   - of_nat_diff and of_nat_mult are no longer default simp rules
   692 
   693 * Method "algebra" solves polynomial equations over (semi)rings using
   694   Groebner bases. The (semi)ring structure is defined by locales and
   695   the tool setup depends on that generic context. Installing the
   696   method for a specific type involves instantiating the locale and
   697   possibly adding declarations for computation on the coefficients.
   698   The method is already instantiated for natural numbers and for the
   699   axiomatic class of idoms with numerals.  See also the paper by
   700   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   701   underlying this architecture of context-aware proof-tools.
   702 
   703 * constant "List.op @" now named "List.append".  Use ML antiquotations
   704 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   705 possible incompatibilities when working on ML level.
   706 
   707 * Constant renames due to introduction of canonical name prefixing for
   708   class package:
   709 
   710     HOL.abs ~> HOL.minus_class.abs
   711     HOL.divide ~> HOL.divide_class.divide
   712     Nat.power ~> Nat.power_class.power
   713     Nat.size ~> Nat.size_class.size
   714     Numeral.number_of ~> Numeral.number_class.number_of
   715     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   716     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   717 
   718 * Rudimentary class target mechanism involves constant renames:
   719 
   720     Orderings.min ~> Orderings.ord_class.min
   721     Orderings.max ~> Orderings.ord_class.max
   722 
   723 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   724 
   725 * new constant "undefined" with axiom "undefined x = undefined"
   726 
   727 * new class "default" with associated constant "default"
   728 
   729 * new function listsum :: 'a list => 'a for arbitrary monoids.
   730   Special syntax: "SUM x <- xs. f x" (and latex variants)
   731 
   732 * new (input only) syntax for Haskell-like list comprehension, eg
   733   [(x,y). x <- xs, y <- ys, x ~= y]
   734   For details see List.thy.
   735 
   736 * The special syntax for function "filter" has changed from [x : xs. P] to
   737   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   738   and for uniformity. INCOMPATIBILITY
   739 
   740 * [a..b] is now defined for arbitrary linear orders.
   741   It used to be defined on nat only, as an abbreviation for [a..<Suc b]
   742   INCOMPATIBILITY
   743 
   744 * Lemma "set_take_whileD" renamed to "set_takeWhileD"
   745 
   746 * new functions sorted and sort in List.
   747 
   748 * function "sgn" is now overloaded and available on int, real, complex
   749   (and other numeric types).
   750   The details: new class "sgn" with function "sgn";
   751   two possible defs of sgn in the classes sgn_if and sgn_div_norm
   752   (as equational assumptions);
   753   ordered_idom now also inherits from sgn_if - INCOMPATIBILITY.
   754 
   755 * New lemma collection field_simps (an extension of ring_simps)
   756   for manipulating (in)equations involving division. Multiplies
   757   with all denominators that can be proved to be non-zero (in equations)
   758   or positive/negative (in inequations).
   759 
   760 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   761   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   762   Removed lemmas field_xyz in Ring_and_Field
   763   because they were subsumed by lemmas xyz.
   764 INCOMPATIBILITY.
   765 
   766 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   767   when generating code.
   768 
   769 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   770   when generating code.
   771 
   772 * Library/Commutative_Ring.thy: switched from recdef to function package;
   773   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   774 
   775 * Some steps towards more uniform lattice theory development in HOL.
   776 
   777     constants "meet" and "join" now named "inf" and "sup"
   778     constant "Meet" now named "Inf"
   779 
   780     classes "meet_semilorder" and "join_semilorder" now named
   781       "lower_semilattice" and "upper_semilattice"
   782     class "lorder" now named "lattice"
   783     class "comp_lat" now named "complete_lattice"
   784 
   785     Instantiation of lattice classes allows explicit definitions
   786     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   787 
   788   INCOMPATIBILITY.  Theorem renames:
   789 
   790     meet_left_le            ~> inf_le1
   791     meet_right_le           ~> inf_le2
   792     join_left_le            ~> sup_ge1
   793     join_right_le           ~> sup_ge2
   794     meet_join_le            ~> inf_sup_ord
   795     le_meetI                ~> le_infI
   796     join_leI                ~> le_supI
   797     le_meet                 ~> le_inf_iff
   798     le_join                 ~> ge_sup_conv
   799     meet_idempotent         ~> inf_idem
   800     join_idempotent         ~> sup_idem
   801     meet_comm               ~> inf_commute
   802     join_comm               ~> sup_commute
   803     meet_leI1               ~> le_infI1
   804     meet_leI2               ~> le_infI2
   805     le_joinI1               ~> le_supI1
   806     le_joinI2               ~> le_supI2
   807     meet_assoc              ~> inf_assoc
   808     join_assoc              ~> sup_assoc
   809     meet_left_comm          ~> inf_left_commute
   810     meet_left_idempotent    ~> inf_left_idem
   811     join_left_comm          ~> sup_left_commute
   812     join_left_idempotent    ~> sup_left_idem
   813     meet_aci                ~> inf_aci
   814     join_aci                ~> sup_aci
   815     le_def_meet             ~> le_iff_inf
   816     le_def_join             ~> le_iff_sup
   817     join_absorp2            ~> sup_absorb2
   818     join_absorp1            ~> sup_absorb1
   819     meet_absorp1            ~> inf_absorb1
   820     meet_absorp2            ~> inf_absorb2
   821     meet_join_absorp        ~> inf_sup_absorb
   822     join_meet_absorp        ~> sup_inf_absorb
   823     distrib_join_le         ~> distrib_sup_le
   824     distrib_meet_le         ~> distrib_inf_le
   825 
   826     add_meet_distrib_left   ~> add_inf_distrib_left
   827     add_join_distrib_left   ~> add_sup_distrib_left
   828     is_join_neg_meet        ~> is_join_neg_inf
   829     is_meet_neg_join        ~> is_meet_neg_sup
   830     add_meet_distrib_right  ~> add_inf_distrib_right
   831     add_join_distrib_right  ~> add_sup_distrib_right
   832     add_meet_join_distribs  ~> add_sup_inf_distribs
   833     join_eq_neg_meet        ~> sup_eq_neg_inf
   834     meet_eq_neg_join        ~> inf_eq_neg_sup
   835     add_eq_meet_join        ~> add_eq_inf_sup
   836     meet_0_imp_0            ~> inf_0_imp_0
   837     join_0_imp_0            ~> sup_0_imp_0
   838     meet_0_eq_0             ~> inf_0_eq_0
   839     join_0_eq_0             ~> sup_0_eq_0
   840     neg_meet_eq_join        ~> neg_inf_eq_sup
   841     neg_join_eq_meet        ~> neg_sup_eq_inf
   842     join_eq_if              ~> sup_eq_if
   843 
   844     mono_meet               ~> mono_inf
   845     mono_join               ~> mono_sup
   846     meet_bool_eq            ~> inf_bool_eq
   847     join_bool_eq            ~> sup_bool_eq
   848     meet_fun_eq             ~> inf_fun_eq
   849     join_fun_eq             ~> sup_fun_eq
   850     meet_set_eq             ~> inf_set_eq
   851     join_set_eq             ~> sup_set_eq
   852     meet1_iff               ~> inf1_iff
   853     meet2_iff               ~> inf2_iff
   854     meet1I                  ~> inf1I
   855     meet2I                  ~> inf2I
   856     meet1D1                 ~> inf1D1
   857     meet2D1                 ~> inf2D1
   858     meet1D2                 ~> inf1D2
   859     meet2D2                 ~> inf2D2
   860     meet1E                  ~> inf1E
   861     meet2E                  ~> inf2E
   862     join1_iff               ~> sup1_iff
   863     join2_iff               ~> sup2_iff
   864     join1I1                 ~> sup1I1
   865     join2I1                 ~> sup2I1
   866     join1I1                 ~> sup1I1
   867     join2I2                 ~> sup1I2
   868     join1CI                 ~> sup1CI
   869     join2CI                 ~> sup2CI
   870     join1E                  ~> sup1E
   871     join2E                  ~> sup2E
   872 
   873     is_meet_Meet            ~> is_meet_Inf
   874     Meet_bool_def           ~> Inf_bool_def
   875     Meet_fun_def            ~> Inf_fun_def
   876     Meet_greatest           ~> Inf_greatest
   877     Meet_lower              ~> Inf_lower
   878     Meet_set_def            ~> Inf_set_def
   879 
   880     Sup_def                 ~> Sup_Inf
   881     Sup_bool_eq             ~> Sup_bool_def
   882     Sup_fun_eq              ~> Sup_fun_def
   883     Sup_set_eq              ~> Sup_set_def
   884 
   885     listsp_meetI            ~> listsp_infI
   886     listsp_meet_eq          ~> listsp_inf_eq
   887 
   888     meet_min                ~> inf_min
   889     join_max                ~> sup_max
   890 
   891 * Classes "order" and "linorder": facts "refl", "trans" and
   892 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   893 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   894 
   895 * Classes "order" and "linorder": 
   896 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   897 proofs changed.
   898 
   899 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   900 INCOMPATIBILITY.
   901 
   902 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   903 INCOMPATIBILITY.
   904 
   905 * Added syntactic class "size"; overloaded constant "size" now has
   906 type "'a::size ==> bool"
   907 
   908 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   909 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   910 
   911 * Added method "lexicographic_order" automatically synthesizes
   912 termination relations as lexicographic combinations of size measures
   913 -- 'function' package.
   914 
   915 * HOL/records: generalised field-update to take a function on the
   916 field rather than the new value: r(|A := x|) is translated to A_update
   917 (K x) r The K-combinator that is internally used is called K_record.
   918 INCOMPATIBILITY: Usage of the plain update functions has to be
   919 adapted.
   920  
   921 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   922 0 * x = 0, which are required for a semiring.  Richer structures do
   923 not inherit from semiring_0 anymore, because this property is a
   924 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   925 semiring_0, there is more to prove, but this is mostly trivial.
   926 
   927 * axclass "recpower" was generalized to arbitrary monoids, not just
   928 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   929 commutativity or a semiring property, add the corresponding classes.
   930 
   931 * Unified locale partial_order with class definition (cf. theory
   932 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   933 
   934 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   935 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   936 Isar level, use abbreviations instead.
   937 
   938 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   939 rarely occuring name references (e.g. ``List.op mem.simps'') require
   940 renaming (e.g. ``List.memberl.simps'').
   941 
   942 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   943 INCOMPATIBILITY.
   944 
   945 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   946 
   947 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   948 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   949 significant changes for setting up numeral syntax for types:
   950 
   951   - new constants Numeral.pred and Numeral.succ instead
   952       of former Numeral.bin_pred and Numeral.bin_succ.
   953   - Use integer operations instead of bin_add, bin_mult and so on.
   954   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   955   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   956 
   957 See HOL/Integ/IntArith.thy for an example setup.
   958 
   959 * New top level command 'normal_form' computes the normal form of a
   960 term that may contain free variables. For example ``normal_form
   961 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   962 suitable for heavy-duty computations because the functions are
   963 compiled to ML first.
   964 
   965 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   966 25 like -->); output depends on the "iff" print_mode, the default is
   967 "A = B" (with priority 50).
   968 
   969 * Renamed constants in HOL.thy and Orderings.thy:
   970     op +   ~> HOL.plus_class.plus
   971     op -   ~> HOL.minus_class.minus
   972     uminus ~> HOL.minus_class.uminus
   973     abs    ~> HOL.abs_class.abs
   974     op *   ~> HOL.times_class.times
   975     op <   ~> HOL.ord_class.less
   976     op <=  ~> HOL.ord_class.less_eq
   977 
   978 Adaptions may be required in the following cases:
   979 
   980 a) User-defined constants using any of the names "plus", "minus", "times",
   981 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   982 may go wrong.
   983 INCOMPATIBILITY: use more specific names.
   984 
   985 b) Variables named "plus", "minus", "times", "less", "less_eq"
   986 INCOMPATIBILITY: use more specific names.
   987 
   988 c) Permutative equations (e.g. "a + b = b + a")
   989 Since the change of names also changes the order of terms, permutative
   990 rewrite rules may get applied in a different order. Experience shows that
   991 this is rarely the case (only two adaptions in the whole Isabelle
   992 distribution).
   993 INCOMPATIBILITY: rewrite proofs
   994 
   995 d) ML code directly refering to constant names
   996 This in general only affects hand-written proof tactics, simprocs and so on.
   997 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   998 of const_name ML antiquotations.
   999 
  1000 * Relations less (<) and less_eq (<=) are also available on type bool.
  1001 Modified syntax to disallow nesting without explicit parentheses,
  1002 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
  1003 
  1004 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1005 
  1006 * Relation composition operator "op O" now has precedence 75 and binds
  1007 stronger than union and intersection. INCOMPATIBILITY.
  1008 
  1009 * The old set interval syntax "{m..n(}" (and relatives) has been
  1010 removed.  Use "{m..<n}" (and relatives) instead.
  1011 
  1012 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1013 "t = s" to False (by simproc "neq_simproc").  For backward
  1014 compatibility this can be disabled by ML "reset use_neq_simproc".
  1015 
  1016 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1017 simp.
  1018 
  1019 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1020 
  1021 * Theorem setsum_mult renamed to setsum_right_distrib.
  1022 
  1023 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1024 ``rule'' method.
  1025 
  1026 * Reimplemented methods ``sat'' and ``satx'', with several
  1027 improvements: goals no longer need to be stated as "<prems> ==>
  1028 False", equivalences (i.e. "=" on type bool) are handled, variable
  1029 names of the form "lit_<n>" are no longer reserved, significant
  1030 speedup.
  1031 
  1032 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1033 zChaff is still supported as well.
  1034 
  1035 * 'inductive' and 'datatype': provide projections of mutual rules,
  1036 bundled as foo_bar.inducts;
  1037 
  1038 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1039 Library.
  1040 
  1041 * Library: moved theory Accessible_Part to main HOL.
  1042 
  1043 * Library: added theory Coinductive_List of potentially infinite lists
  1044 as greatest fixed-point.
  1045 
  1046 * Library: added theory AssocList which implements (finite) maps as
  1047 association lists.
  1048 
  1049 * Added proof method ``evaluation'' for efficiently solving a goal
  1050 (i.e. a boolean expression) by compiling it to ML. The goal is
  1051 "proved" (via an oracle) if it evaluates to True.
  1052 
  1053 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1054 also when invoked by the simplifier.  This results in the simplifier
  1055 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1056 fast_arith_split_limit to 0 to obtain the old behavior.
  1057 
  1058 * Support for hex (0x20) and binary (0b1001) numerals.
  1059 
  1060 * New method: reify eqs (t), where eqs are equations for an
  1061 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1062 parameter, computes a term s::'b and a list xs::'a list and proves the
  1063 theorem I xs s = t. This is also known as reification or quoting. The
  1064 resulting theorem is applied to the subgoal to substitute t with I xs
  1065 s.  If t is omitted, the subgoal itself is reified.
  1066 
  1067 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1068 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1069 where f is supposed to be a computable function (in the sense of code
  1070 generattion). The method uses reify to compute s and xs as above then
  1071 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1072 r and finally gets the theorem t = r, which is again applied to the
  1073 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1074 
  1075 * Reflection: Automatic reification now handels binding, an example
  1076 is available in HOL/ex/ReflectionEx.thy
  1077 
  1078 
  1079 *** HOL-Algebra ***
  1080 
  1081 * Formalisation of ideals and the quotient construction over rings.
  1082 
  1083 * Order and lattice theory no longer based on records.
  1084 INCOMPATIBILITY.
  1085 
  1086 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1087 greatest_closed.  INCOMPATIBILITY.
  1088 
  1089 * Method algebra is now set up via an attribute.  For examples see
  1090 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1091 of algebraic structures.
  1092 
  1093 * Renamed theory CRing to Ring.
  1094 
  1095 
  1096 *** HOL-Complex ***
  1097 
  1098 * Theory Real: new method ferrack implements quantifier elimination
  1099 for linear arithmetic over the reals. The quantifier elimination
  1100 feature is used only for decision, for compatibility with arith. This
  1101 means a goal is either solved or left unchanged, no simplification.
  1102 
  1103 * Hyperreal: Functions root and sqrt are now defined on negative real
  1104 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1105 Nonnegativity side conditions have been removed from many lemmas, so
  1106 that more subgoals may now be solved by simplification; potential
  1107 INCOMPATIBILITY.
  1108 
  1109 * Real: New axiomatic classes formalize real normed vector spaces and
  1110 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1111 and norm :: 'a => real.
  1112 
  1113 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1114 from reals into other types. The overloaded constant Reals :: 'a set
  1115 is now defined as range of_real; potential INCOMPATIBILITY.
  1116 
  1117 * Real: ML code generation is supported now and hence also quickcheck.
  1118 Reals are implemented as arbitrary precision rationals.
  1119 
  1120 * Hyperreal: Several constants that previously worked only for the
  1121 reals have been generalized, so they now work over arbitrary vector
  1122 spaces. Type annotations may need to be added in some cases; potential
  1123 INCOMPATIBILITY.
  1124 
  1125   Infinitesimal  :: ('a::real_normed_vector) star set
  1126   HFinite        :: ('a::real_normed_vector) star set
  1127   HInfinite      :: ('a::real_normed_vector) star set
  1128   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1129   monad          :: ('a::real_normed_vector) star => 'a star set
  1130   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1131   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1132   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1133   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1134   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1135   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1136   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1137   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1138   sgn            :: 'a::real_normed_vector => 'a
  1139   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1140 
  1141 * Complex: Some complex-specific constants are now abbreviations for
  1142 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1143 hnorm.  Other constants have been entirely removed in favor of the
  1144 polymorphic versions (INCOMPATIBILITY):
  1145 
  1146   approx        <-- capprox
  1147   HFinite       <-- CFinite
  1148   HInfinite     <-- CInfinite
  1149   Infinitesimal <-- CInfinitesimal
  1150   monad         <-- cmonad
  1151   galaxy        <-- cgalaxy
  1152   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1153   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1154   (ns)deriv     <-- (ns)cderiv
  1155 
  1156 
  1157 *** ML ***
  1158 
  1159 * ML basics: just one true type int, which coincides with IntInf.int
  1160 (even on SML/NJ).
  1161 
  1162 * Generic arithmetic modules: Tools/rat.ML, Tools/float.ML
  1163 
  1164 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1165 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1166 init only required for impure data.  INCOMPATIBILITY: empty really
  1167 need to be empty (no dependencies on theory content!)
  1168 
  1169 * ML within Isar: antiquotations allow to embed statically-checked
  1170 formal entities in the source, referring to the context available at
  1171 compile-time.  For example:
  1172 
  1173 ML {* @{typ "'a => 'b"} *}
  1174 ML {* @{term "%x. x"} *}
  1175 ML {* @{prop "x == y"} *}
  1176 ML {* @{ctyp "'a => 'b"} *}
  1177 ML {* @{cterm "%x. x"} *}
  1178 ML {* @{cprop "x == y"} *}
  1179 ML {* @{thm asm_rl} *}
  1180 ML {* @{thms asm_rl} *}
  1181 ML {* @{const_name c} *}
  1182 ML {* @{const_syntax c} *}
  1183 ML {* @{context} *}
  1184 ML {* @{theory} *}
  1185 ML {* @{theory Pure} *}
  1186 ML {* @{simpset} *}
  1187 ML {* @{claset} *}
  1188 ML {* @{clasimpset} *}
  1189 
  1190 The same works for sources being ``used'' within an Isar context.
  1191 
  1192 * ML in Isar: improved error reporting; extra verbosity with
  1193 Toplevel.debug enabled.
  1194 
  1195 * Pure/library:
  1196 
  1197   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1198   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1199 
  1200 The semantics of "burrow" is: "take a function with *simulatanously*
  1201 transforms a list of value, and apply it *simulatanously* to a list of
  1202 list of values of the appropriate type". Compare this with "map" which
  1203 would *not* apply its argument function simulatanously but in
  1204 sequence; "fold_burrow" has an additional context.
  1205 
  1206 * Pure/library: functions map2 and fold2 with curried syntax for
  1207 simultanous mapping and folding:
  1208 
  1209     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1210     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1211 
  1212 * Pure/library: indexed lists - some functions in the Isabelle library
  1213 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1214 given more convenient names and signatures reminiscent of similar
  1215 functions for alists, tables, etc:
  1216 
  1217   val nth: 'a list -> int -> 'a 
  1218   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1219   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1220 
  1221 Note that fold_index starts counting at index 0, not 1 like foldln
  1222 used to.
  1223 
  1224 * Pure/library: added general ``divide_and_conquer'' combinator on
  1225 lists.
  1226 
  1227 * Pure/General/table.ML: the join operations now works via exceptions
  1228 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1229 admits slightly more efficient complex applications.
  1230 
  1231 * Pure: datatype Context.generic joins theory/Proof.context and
  1232 provides some facilities for code that works in either kind of
  1233 context, notably GenericDataFun for uniform theory and proof data.
  1234 
  1235 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1236 use Context.generic instead of just theory.
  1237 
  1238 * Pure: simplified internal attribute type, which is now always
  1239 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1240 vs. local (Proof.context) attributes have been discontinued, while
  1241 minimizing code duplication.  Thm.rule_attribute and
  1242 Thm.declaration_attribute build canonical attributes; see also
  1243 structure Context for further operations on Context.generic, notably
  1244 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1245 declarations and definitions.
  1246 
  1247 * Pure/kernel: consts certification ignores sort constraints given in
  1248 signature declarations.  (This information is not relevant to the
  1249 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1250 potential INCOMPATIBILITY.
  1251 
  1252 * Pure: axiomatic type classes are now purely definitional, with
  1253 explicit proofs of class axioms and super class relations performed
  1254 internally.  See Pure/axclass.ML for the main internal interfaces --
  1255 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1256 AxClass.axiomatize_class/classrel/arity supercede
  1257 Sign.add_classes/classrel/arities.
  1258 
  1259 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1260 global/local versions on theory vs. Proof.context have been
  1261 discontinued; Attrib.syntax and Method.syntax have been adapted
  1262 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1263 attributes, methods, etc.
  1264 
  1265 * Pure: several functions of signature "... -> theory -> theory * ..."
  1266 have been reoriented to "... -> theory -> ... * theory" in order to
  1267 allow natural usage in combination with the ||>, ||>>, |-> and
  1268 fold_map combinators.
  1269 
  1270 * Pure: official theorem names (closed derivations) and additional
  1271 comments (tags) are now strictly separate.  Name hints -- which are
  1272 maintained as tags -- may be attached any time without affecting the
  1273 derivation.
  1274 
  1275 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1276 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1277 achieve the old behaviour.
  1278 
  1279 * Pure: the "Goal" constant is now called "prop", supporting a
  1280 slightly more general idea of ``protecting'' meta-level rule
  1281 statements.
  1282 
  1283 * Pure: Logic.(un)varify only works in a global context, which is now
  1284 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1285 Logic.legacy_(un)varify as temporary workaround.
  1286 
  1287 * Pure: structure Name provides scalable operations for generating
  1288 internal variable names, notably Name.variants etc.  This replaces
  1289 some popular functions from term.ML:
  1290 
  1291   Term.variant		->  Name.variant
  1292   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1293   Term.invent_names	->  Name.invent_list
  1294 
  1295 Note that low-level renaming rarely occurs in new code -- operations
  1296 from structure Variable are used instead (see below).
  1297 
  1298 * Pure: structure Variable provides fundamental operations for proper
  1299 treatment of fixed/schematic variables in a context.  For example,
  1300 Variable.import introduces fixes for schematics of given facts and
  1301 Variable.export reverses the effect (up to renaming) -- this replaces
  1302 various freeze_thaw operations.
  1303 
  1304 * Pure: structure Goal provides simple interfaces for
  1305 init/conclude/finish and tactical prove operations (replacing former
  1306 Tactic.prove).  Goal.prove is the canonical way to prove results
  1307 within a given context; Goal.prove_global is a degraded version for
  1308 theory level goals, including a global Drule.standard.  Note that
  1309 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1310 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1311 in a locale context).
  1312 
  1313 * Isar: simplified treatment of user-level errors, using exception
  1314 ERROR of string uniformly.  Function error now merely raises ERROR,
  1315 without any side effect on output channels.  The Isar toplevel takes
  1316 care of proper display of ERROR exceptions.  ML code may use plain
  1317 handle/can/try; cat_error may be used to concatenate errors like this:
  1318 
  1319   ... handle ERROR msg => cat_error msg "..."
  1320 
  1321 Toplevel ML code (run directly or through the Isar toplevel) may be
  1322 embedded into the Isar toplevel with exception display/debug like
  1323 this:
  1324 
  1325   Isar.toplevel (fn () => ...)
  1326 
  1327 INCOMPATIBILITY, removed special transform_error facilities, removed
  1328 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1329 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1330 -- use plain ERROR instead.
  1331 
  1332 * Isar: theory setup now has type (theory -> theory), instead of a
  1333 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1334 
  1335 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1336 subject to ProofContext.debug/verbose flags.
  1337 
  1338 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1339 theory before entering a proof state.  Transactions now always see a
  1340 quasi-functional intermediate checkpoint, both in interactive and
  1341 batch mode.
  1342 
  1343 * Simplifier: the simpset of a running simplification process now
  1344 contains a proof context (cf. Simplifier.the_context), which is the
  1345 very context that the initial simpset has been retrieved from (by
  1346 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1347 (solver, looper etc.) may depend on arbitrary proof data.
  1348 
  1349 * Simplifier.inherit_context inherits the proof context (plus the
  1350 local bounds) of the current simplification process; any simproc
  1351 etc. that calls the Simplifier recursively should do this!  Removed
  1352 former Simplifier.inherit_bounds, which is already included here --
  1353 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1354 specify an explicit context using Simplifier.context/theory_context.
  1355 
  1356 * Simplifier/Classical Reasoner: more abstract interfaces
  1357 change_simpset/claset for modifying the simpset/claset reference of a
  1358 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1359 INCOMPATIBILITY.
  1360 
  1361 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1362 "Trueprop" etc.
  1363 
  1364 
  1365 *** System ***
  1366 
  1367 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1368 locations -- now includes the Isabelle version identifier as well.
  1369 This simplifies use of multiple Isabelle installations.
  1370 
  1371 * isabelle-process: option -S (secure mode) disables some critical
  1372 operations, notably runtime compilation and evaluation of ML source
  1373 code.
  1374 
  1375 * Support for multithreading, using Poly/ML 5.1 (internal version from
  1376 CVS). The theory loader exploits parallelism when processing independent
  1377 theories, following the header specifications. The maximum number of
  1378 worker threads is specified via usedir option -M or the "max-threads"
  1379 setting in Proof General. A speedup factor of 1.5--3.5 can be expected
  1380 on a 4-core machine, and up to 6 on a 8-core machine. User-code needs to
  1381 observe certain guidelines for thread-safe programming, see appendix A
  1382 in the Isar Implementation manual.
  1383 
  1384 
  1385 New in Isabelle2005 (October 2005)
  1386 ----------------------------------
  1387 
  1388 *** General ***
  1389 
  1390 * Theory headers: the new header syntax for Isar theories is
  1391 
  1392   theory <name>
  1393   imports <theory1> ... <theoryN>
  1394   uses <file1> ... <fileM>
  1395   begin
  1396 
  1397 where the 'uses' part is optional.  The previous syntax
  1398 
  1399   theory <name> = <theory1> + ... + <theoryN>:
  1400 
  1401 will disappear in the next release.  Use isatool fixheaders to convert
  1402 existing theory files.  Note that there is no change in ancient
  1403 non-Isar theories now, but these will disappear soon.
  1404 
  1405 * Theory loader: parent theories can now also be referred to via
  1406 relative and absolute paths.
  1407 
  1408 * Command 'find_theorems' searches for a list of criteria instead of a
  1409 list of constants. Known criteria are: intro, elim, dest, name:string,
  1410 simp:term, and any term. Criteria can be preceded by '-' to select
  1411 theorems that do not match. Intro, elim, dest select theorems that
  1412 match the current goal, name:s selects theorems whose fully qualified
  1413 name contain s, and simp:term selects all simplification rules whose
  1414 lhs match term.  Any other term is interpreted as pattern and selects
  1415 all theorems matching the pattern. Available in ProofGeneral under
  1416 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1417 
  1418   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1419 
  1420 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1421 matching the current goal as introduction rule and not having "HOL."
  1422 in their name (i.e. not being defined in theory HOL).
  1423 
  1424 * Command 'thms_containing' has been discontinued in favour of
  1425 'find_theorems'; INCOMPATIBILITY.
  1426 
  1427 * Communication with Proof General is now 8bit clean, which means that
  1428 Unicode text in UTF-8 encoding may be used within theory texts (both
  1429 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1430 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1431 
  1432   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1433   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1434 
  1435 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1436 Classical Reasoner.  Typical big applications run around 2 times
  1437 faster.
  1438 
  1439 
  1440 *** Document preparation ***
  1441 
  1442 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1443 of raw sources.  Only those symbols that do not require additional
  1444 LaTeX packages (depending on comments in isabellesym.sty) are
  1445 displayed properly, everything else is left verbatim.  isatool display
  1446 and isatool print are used as front ends (these are subject to the
  1447 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1448 
  1449 * Command tags control specific markup of certain regions of text,
  1450 notably folding and hiding.  Predefined tags include "theory" (for
  1451 theory begin and end), "proof" for proof commands, and "ML" for
  1452 commands involving ML code; the additional tags "visible" and
  1453 "invisible" are unused by default.  Users may give explicit tag
  1454 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1455 interpretation of tags is determined by the LaTeX job during document
  1456 preparation: see option -V of isatool usedir, or options -n and -t of
  1457 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1458 \isadroptag.
  1459 
  1460 Several document versions may be produced at the same time via isatool
  1461 usedir (the generated index.html will link all of them).  Typical
  1462 specifications include ''-V document=theory,proof,ML'' to present
  1463 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1464 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1465 these parts without any formal replacement text.  The Isabelle site
  1466 default settings produce ''document'' and ''outline'' versions as
  1467 specified above.
  1468 
  1469 * Several new antiquotations:
  1470 
  1471   @{term_type term} prints a term with its type annotated;
  1472 
  1473   @{typeof term} prints the type of a term;
  1474 
  1475   @{const const} is the same as @{term const}, but checks that the
  1476   argument is a known logical constant;
  1477 
  1478   @{term_style style term} and @{thm_style style thm} print a term or
  1479   theorem applying a "style" to it
  1480 
  1481   @{ML text}
  1482 
  1483 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1484 definitions, equations, inequations etc., 'concl' printing only the
  1485 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1486 to print the specified premise.  TermStyle.add_style provides an ML
  1487 interface for introducing further styles.  See also the "LaTeX Sugar"
  1488 document practical applications.  The ML antiquotation prints
  1489 type-checked ML expressions verbatim.
  1490 
  1491 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1492 and 'text' support optional locale specification '(in loc)', which
  1493 specifies the default context for interpreting antiquotations.  For
  1494 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1495 
  1496 * Option 'locale=NAME' of antiquotations specifies an alternative
  1497 context interpreting the subsequent argument.  For example: @{thm
  1498 [locale=lattice] inf_assoc}.
  1499 
  1500 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1501 a proof context.
  1502 
  1503 * Proper output of antiquotations for theory commands involving a
  1504 proof context (such as 'locale' or 'theorem (in loc) ...').
  1505 
  1506 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1507 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1508 
  1509 * isatool usedir: new option -C (default true) controls whether option
  1510 -D should include a copy of the original document directory; -C false
  1511 prevents unwanted effects such as copying of administrative CVS data.
  1512 
  1513 
  1514 *** Pure ***
  1515 
  1516 * Considerably improved version of 'constdefs' command.  Now performs
  1517 automatic type-inference of declared constants; additional support for
  1518 local structure declarations (cf. locales and HOL records), see also
  1519 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1520 sequential dependencies of definitions within a single 'constdefs'
  1521 section; moreover, the declared name needs to be an identifier.  If
  1522 all fails, consider to fall back on 'consts' and 'defs' separately.
  1523 
  1524 * Improved indexed syntax and implicit structures.  First of all,
  1525 indexed syntax provides a notational device for subscripted
  1526 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1527 expressions.  Secondly, in a local context with structure
  1528 declarations, number indexes \<^sub>n or the empty index (default
  1529 number 1) refer to a certain fixed variable implicitly; option
  1530 show_structs controls printing of implicit structures.  Typical
  1531 applications of these concepts involve record types and locales.
  1532 
  1533 * New command 'no_syntax' removes grammar declarations (and
  1534 translations) resulting from the given syntax specification, which is
  1535 interpreted in the same manner as for the 'syntax' command.
  1536 
  1537 * 'Advanced' translation functions (parse_translation etc.) may depend
  1538 on the signature of the theory context being presently used for
  1539 parsing/printing, see also isar-ref manual.
  1540 
  1541 * Improved 'oracle' command provides a type-safe interface to turn an
  1542 ML expression of type theory -> T -> term into a primitive rule of
  1543 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1544 is already included here); see also FOL/ex/IffExample.thy;
  1545 INCOMPATIBILITY.
  1546 
  1547 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1548 before); "cI" is no longer bound, use "c.intro" instead.
  1549 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1550 axclasses vs. locales.
  1551 
  1552 * Improved internal renaming of symbolic identifiers -- attach primes
  1553 instead of base 26 numbers.
  1554 
  1555 * New flag show_question_marks controls printing of leading question
  1556 marks in schematic variable names.
  1557 
  1558 * In schematic variable names, *any* symbol following \<^isub> or
  1559 \<^isup> is now treated as part of the base name.  For example, the
  1560 following works without printing of awkward ".0" indexes:
  1561 
  1562   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1563     by simp
  1564 
  1565 * Inner syntax includes (*(*nested*) comments*).
  1566 
  1567 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1568 annotations as "(00...)".
  1569 
  1570 * Clear separation of logical types and nonterminals, where the latter
  1571 may only occur in 'syntax' specifications or type abbreviations.
  1572 Before that distinction was only partially implemented via type class
  1573 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1574 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1575 exotic syntax specifications may require further adaption
  1576 (e.g. Cube/Cube.thy).
  1577 
  1578 * Removed obsolete type class "logic", use the top sort {} instead.
  1579 Note that non-logical types should be declared as 'nonterminals'
  1580 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1581 specifications.
  1582 
  1583 * Attributes 'induct' and 'cases': type or set names may now be
  1584 locally fixed variables as well.
  1585 
  1586 * Simplifier: can now control the depth to which conditional rewriting
  1587 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1588 Limit.
  1589 
  1590 * Simplifier: simplification procedures may now take the current
  1591 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1592 interface), which is very useful for calling the Simplifier
  1593 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1594 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1595 low-level mk_simproc no longer applies Logic.varify internally, to
  1596 allow for use in a context of fixed variables.
  1597 
  1598 * thin_tac now works even if the assumption being deleted contains !!
  1599 or ==>.  More generally, erule now works even if the major premise of
  1600 the elimination rule contains !! or ==>.
  1601 
  1602 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1603 
  1604 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1605 from Pure, which contains all common declarations already.  Both
  1606 theories are defined via plain Isabelle/Isar .thy files.
  1607 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1608 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1609 use isatool fixcpure to adapt your theory and ML sources.
  1610 
  1611 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1612 selections of theorems in named facts via index ranges.
  1613 
  1614 * 'print_theorems': in theory mode, really print the difference
  1615 wrt. the last state (works for interactive theory development only),
  1616 in proof mode print all local facts (cf. 'print_facts');
  1617 
  1618 * 'hide': option '(open)' hides only base names.
  1619 
  1620 * More efficient treatment of intermediate checkpoints in interactive
  1621 theory development.
  1622 
  1623 * Code generator is now invoked via code_module (incremental code
  1624 generation) and code_library (modular code generation, ML structures
  1625 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1626 must be quoted when used as identifiers.
  1627 
  1628 * New 'value' command for reading, evaluating and printing terms using
  1629 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1630 quoted when used as identifier.
  1631 
  1632 
  1633 *** Locales ***
  1634 
  1635 * New commands for the interpretation of locale expressions in
  1636 theories (1), locales (2) and proof contexts (3).  These generate
  1637 proof obligations from the expression specification.  After the
  1638 obligations have been discharged, theorems of the expression are added
  1639 to the theory, target locale or proof context.  The synopsis of the
  1640 commands is a follows:
  1641 
  1642   (1) interpretation expr inst
  1643   (2) interpretation target < expr
  1644   (3) interpret expr inst
  1645 
  1646 Interpretation in theories and proof contexts require a parameter
  1647 instantiation of terms from the current context.  This is applied to
  1648 specifications and theorems of the interpreted expression.
  1649 Interpretation in locales only permits parameter renaming through the
  1650 locale expression.  Interpretation is smart in that interpretations
  1651 that are active already do not occur in proof obligations, neither are
  1652 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1653 inspect active interpretations of a particular locale.  For details,
  1654 see the Isar Reference manual.  Examples can be found in
  1655 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1656 
  1657 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1658 'interpret' instead.
  1659 
  1660 * New context element 'constrains' for adding type constraints to
  1661 parameters.
  1662 
  1663 * Context expressions: renaming of parameters with syntax
  1664 redeclaration.
  1665 
  1666 * Locale declaration: 'includes' disallowed.
  1667 
  1668 * Proper static binding of attribute syntax -- i.e. types / terms /
  1669 facts mentioned as arguments are always those of the locale definition
  1670 context, independently of the context of later invocations.  Moreover,
  1671 locale operations (renaming and type / term instantiation) are applied
  1672 to attribute arguments as expected.
  1673 
  1674 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1675 actual attributes; rare situations may require Attrib.attribute to
  1676 embed those attributes into Attrib.src that lack concrete syntax.
  1677 Attribute implementations need to cooperate properly with the static
  1678 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1679 Attrib.XXX_thm etc. already do the right thing without further
  1680 intervention.  Only unusual applications -- such as "where" or "of"
  1681 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1682 on the context and the facts involved -- may have to assign parsed
  1683 values to argument tokens explicitly.
  1684 
  1685 * Changed parameter management in theorem generation for long goal
  1686 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1687 theorem statement in rare situations.
  1688 
  1689 * Locale inspection command 'print_locale' omits notes elements.  Use
  1690 'print_locale!' to have them included in the output.
  1691 
  1692 
  1693 *** Provers ***
  1694 
  1695 * Provers/hypsubst.ML: improved version of the subst method, for
  1696 single-step rewriting: it now works in bound variable contexts. New is
  1697 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1698 rewrite a different subterm than the original subst method, which is
  1699 still available as 'simplesubst'.
  1700 
  1701 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1702 and quasi orders.
  1703 
  1704 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1705 reflexive-transitive closure of relations.
  1706 
  1707 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1708 limit (previously hard-coded with a value of 20) user-definable.
  1709 
  1710 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1711 is peformed already.  Object-logics merely need to finish their
  1712 initial simpset configuration as before.  INCOMPATIBILITY.
  1713 
  1714 
  1715 *** HOL ***
  1716 
  1717 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1718 
  1719   syntax (epsilon)
  1720     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1721 
  1722 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1723 and x-symbol; use option '-m epsilon' to get it actually printed.
  1724 Moreover, the mathematically important symbolic identifier \<epsilon>
  1725 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1726 
  1727 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1728 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1729 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1730 support corresponding Isar calculations.
  1731 
  1732 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1733 instead of ":".
  1734 
  1735 * theory SetInterval: changed the syntax for open intervals:
  1736 
  1737   Old       New
  1738   {..n(}    {..<n}
  1739   {)n..}    {n<..}
  1740   {m..n(}   {m..<n}
  1741   {)m..n}   {m<..n}
  1742   {)m..n(}  {m<..<n}
  1743 
  1744 The old syntax is still supported but will disappear in the next
  1745 release.  For conversion use the following Emacs search and replace
  1746 patterns (these are not perfect but work quite well):
  1747 
  1748   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1749   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1750 
  1751 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1752 equalities in commutative rings; method 'algebra' provides a generic
  1753 interface.
  1754 
  1755 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1756 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1757 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1758 be a tuple pattern.
  1759 
  1760 Some new syntax forms are available:
  1761 
  1762   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1763   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1764   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1765   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1766 
  1767 The latter form "\<Sum>x < k. e" used to be based on a separate
  1768 function "Summation", which has been discontinued.
  1769 
  1770 * theory Finite_Set: in structured induction proofs, the insert case
  1771 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1772 (insert F x)'.
  1773 
  1774 * The 'refute' command has been extended to support a much larger
  1775 fragment of HOL, including axiomatic type classes, constdefs and
  1776 typedefs, inductive datatypes and recursion.
  1777 
  1778 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1779 Requires zChaff with proof generation to be installed.  See
  1780 HOL/ex/SAT_Examples.thy for examples.
  1781 
  1782 * Datatype induction via method 'induct' now preserves the name of the
  1783 induction variable. For example, when proving P(xs::'a list) by
  1784 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1785 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1786 in unstructured proof scripts.
  1787 
  1788 * Reworked implementation of records.  Improved scalability for
  1789 records with many fields, avoiding performance problems for type
  1790 inference. Records are no longer composed of nested field types, but
  1791 of nested extension types. Therefore the record type only grows linear
  1792 in the number of extensions and not in the number of fields.  The
  1793 top-level (users) view on records is preserved.  Potential
  1794 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1795 old record representation. The type generated for a record is called
  1796 <record_name>_ext_type.
  1797 
  1798 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1799 proofs triggered by a record definition or a simproc (if
  1800 quick_and_dirty is enabled).  Definitions of large records can take
  1801 quite long.
  1802 
  1803 New simproc record_upd_simproc for simplification of multiple record
  1804 updates enabled by default.  Moreover, trivial updates are also
  1805 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1806 occasionally, since simplification is more powerful by default.
  1807 
  1808 * typedef: proper support for polymorphic sets, which contain extra
  1809 type-variables in the term.
  1810 
  1811 * Simplifier: automatically reasons about transitivity chains
  1812 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1813 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1814 old proofs break occasionally as simplification may now solve more
  1815 goals than previously.
  1816 
  1817 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1818 present.  Works for all partial orders (class "order"), in particular
  1819 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1820 just like y <= x.
  1821 
  1822 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1823 bound variable or a constant then the let is unfolded.  Otherwise
  1824 first a is simplified to b, and then f b is simplified to g. If
  1825 possible we abstract b from g arriving at "let x = b in h x",
  1826 otherwise we unfold the let and arrive at g.  The simproc can be
  1827 enabled/disabled by the reference use_let_simproc.  Potential
  1828 INCOMPATIBILITY since simplification is more powerful by default.
  1829 
  1830 * Classical reasoning: the meson method now accepts theorems as arguments.
  1831 
  1832 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1833 jobs to provide advice on the provability of subgoals.
  1834 
  1835 * Theory OrderedGroup and Ring_and_Field: various additions and
  1836 improvements to faciliate calculations involving equalities and
  1837 inequalities.
  1838 
  1839 The following theorems have been eliminated or modified
  1840 (INCOMPATIBILITY):
  1841 
  1842   abs_eq             now named abs_of_nonneg
  1843   abs_of_ge_0        now named abs_of_nonneg
  1844   abs_minus_eq       now named abs_of_nonpos
  1845   imp_abs_id         now named abs_of_nonneg
  1846   imp_abs_neg_id     now named abs_of_nonpos
  1847   mult_pos           now named mult_pos_pos
  1848   mult_pos_le        now named mult_nonneg_nonneg
  1849   mult_pos_neg_le    now named mult_nonneg_nonpos
  1850   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1851   mult_neg           now named mult_neg_neg
  1852   mult_neg_le        now named mult_nonpos_nonpos
  1853 
  1854 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1855      
  1856      zero_le_square
  1857      not_square_less_zero 
  1858 
  1859   The following lemmas have been deleted from Real/RealPow:
  1860   
  1861      realpow_zero_zero
  1862      realpow_two
  1863      realpow_less
  1864      zero_le_power
  1865      realpow_two_le
  1866      abs_realpow_two
  1867      realpow_two_abs     
  1868 
  1869 * Theory Parity: added rules for simplifying exponents.
  1870 
  1871 * Theory List:
  1872 
  1873 The following theorems have been eliminated or modified
  1874 (INCOMPATIBILITY):
  1875 
  1876   list_all_Nil       now named list_all.simps(1)
  1877   list_all_Cons      now named list_all.simps(2)
  1878   list_all_conv      now named list_all_iff
  1879   set_mem_eq         now named mem_iff
  1880 
  1881 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1882 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1883 
  1884 
  1885 *** HOL-Complex ***
  1886 
  1887 * Theory RealDef: better support for embedding natural numbers and
  1888 integers in the reals.
  1889 
  1890 The following theorems have been eliminated or modified
  1891 (INCOMPATIBILITY):
  1892 
  1893   exp_ge_add_one_self  now requires no hypotheses
  1894   real_of_int_add      reversed direction of equality (use [symmetric])
  1895   real_of_int_minus    reversed direction of equality (use [symmetric])
  1896   real_of_int_diff     reversed direction of equality (use [symmetric])
  1897   real_of_int_mult     reversed direction of equality (use [symmetric])
  1898 
  1899 * Theory RComplete: expanded support for floor and ceiling functions.
  1900 
  1901 * Theory Ln is new, with properties of the natural logarithm
  1902 
  1903 * Hyperreal: There is a new type constructor "star" for making
  1904 nonstandard types.  The old type names are now type synonyms:
  1905 
  1906   hypreal = real star
  1907   hypnat = nat star
  1908   hcomplex = complex star
  1909 
  1910 * Hyperreal: Many groups of similarly-defined constants have been
  1911 replaced by polymorphic versions (INCOMPATIBILITY):
  1912 
  1913   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1914 
  1915   starset      <-- starsetNat, starsetC
  1916   *s*          <-- *sNat*, *sc*
  1917   starset_n    <-- starsetNat_n, starsetC_n
  1918   *sn*         <-- *sNatn*, *scn*
  1919   InternalSets <-- InternalNatSets, InternalCSets
  1920 
  1921   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1922   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1923   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1924   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1925   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1926 
  1927 * Hyperreal: Many type-specific theorems have been removed in favor of
  1928 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1929 
  1930   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1931   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1932   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1933   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1934   right_minus <-- hypreal_add_minus
  1935   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1936   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1937   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1938   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1939   mult_1_right <-- hcomplex_mult_one_right
  1940   mult_zero_left <-- hcomplex_mult_zero_left
  1941   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1942   right_distrib <-- hypnat_add_mult_distrib2
  1943   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1944   right_inverse <-- hypreal_mult_inverse
  1945   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1946   order_refl <-- {hypreal,hypnat}_le_refl
  1947   order_trans <-- {hypreal,hypnat}_le_trans
  1948   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1949   order_less_le <-- {hypreal,hypnat}_less_le
  1950   linorder_linear <-- {hypreal,hypnat}_le_linear
  1951   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1952   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1953   add_nonneg_nonneg <-- hypreal_le_add_order
  1954 
  1955 * Hyperreal: Separate theorems having to do with type-specific
  1956 versions of constants have been merged into theorems that apply to the
  1957 new polymorphic constants (INCOMPATIBILITY):
  1958 
  1959   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1960   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1961   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1962   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1963   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1964   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1965   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1966   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1967   STAR_diff <-- {STAR,STARC}_diff
  1968   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1969     STARC_hcomplex_of_complex}_image_subset
  1970   starset_n_Un <-- starset{Nat,C}_n_Un
  1971   starset_n_Int <-- starset{Nat,C}_n_Int
  1972   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1973   starset_n_diff <-- starset{Nat,C}_n_diff
  1974   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1975   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1976   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1977   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1978   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1979   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1980   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1981   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1982   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1983   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1984   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1985   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1986   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1987   starfun_diff <-- starfun{C,RC,CR}_diff
  1988   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1989   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1990   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1991   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1992   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1993   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1994   starfun_Id <-- starfunC_Id
  1995   starfun_approx <-- starfun{Nat,CR}_approx
  1996   starfun_capprox <-- starfun{C,RC}_capprox
  1997   starfun_abs <-- starfunNat_rabs
  1998   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1999   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2000   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2001   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2002   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2003   starfun_add_approx <-- starfunCR_add_approx
  2004   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2005   starfun_divide <-- starfun{C,CR,RC}_divide
  2006   starfun_n <-- starfun{Nat,C}_n
  2007   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2008   starfun_n_add <-- starfun{Nat,C}_n_add
  2009   starfun_n_add_minus <-- starfunNat_n_add_minus
  2010   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2011   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2012   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2013 
  2014   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2015   star_n_minus <-- {hypreal,hcomplex}_minus
  2016   star_n_diff <-- {hypreal,hcomplex}_diff
  2017   star_n_mult <-- {hypreal,hcomplex}_mult
  2018   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2019   star_n_le <-- {hypreal,hypnat}_le
  2020   star_n_less <-- {hypreal,hypnat}_less
  2021   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2022   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2023   star_n_abs <-- hypreal_hrabs
  2024   star_n_divide <-- hcomplex_divide
  2025 
  2026   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2027   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2028   star_of_diff <-- hypreal_of_real_diff
  2029   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2030   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2031   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2032   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2033   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2034   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2035   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2036   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2037   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2038   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2039   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2040   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2041   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2042   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2043   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2044   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2045   star_of_power <-- hypreal_of_real_power
  2046   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2047 
  2048 * Hyperreal: new method "transfer" that implements the transfer
  2049 principle of nonstandard analysis. With a subgoal that mentions
  2050 nonstandard types like "'a star", the command "apply transfer"
  2051 replaces it with an equivalent one that mentions only standard types.
  2052 To be successful, all free variables must have standard types; non-
  2053 standard variables must have explicit universal quantifiers.
  2054 
  2055 * Hyperreal: A theory of Taylor series.
  2056 
  2057 
  2058 *** HOLCF ***
  2059 
  2060 * Discontinued special version of 'constdefs' (which used to support
  2061 continuous functions) in favor of the general Pure one with full
  2062 type-inference.
  2063 
  2064 * New simplification procedure for solving continuity conditions; it
  2065 is much faster on terms with many nested lambda abstractions (cubic
  2066 instead of exponential time).
  2067 
  2068 * New syntax for domain package: selector names are now optional.
  2069 Parentheses should be omitted unless argument is lazy, for example:
  2070 
  2071   domain 'a stream = cons "'a" (lazy "'a stream")
  2072 
  2073 * New command 'fixrec' for defining recursive functions with pattern
  2074 matching; defining multiple functions with mutual recursion is also
  2075 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2076 sinr, or any data constructor defined by the domain package. The given
  2077 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2078 syntax and examples.
  2079 
  2080 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2081 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2082 but the proof obligation additionally includes an admissibility
  2083 requirement. The packages generate instances of class cpo or pcpo,
  2084 with continuity and strictness theorems for Rep and Abs.
  2085 
  2086 * HOLCF: Many theorems have been renamed according to a more standard naming
  2087 scheme (INCOMPATIBILITY):
  2088 
  2089   foo_inject:  "foo$x = foo$y ==> x = y"
  2090   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2091   foo_less:    "(foo$x << foo$y) = (x << y)"
  2092   foo_strict:  "foo$UU = UU"
  2093   foo_defined: "... ==> foo$x ~= UU"
  2094   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2095 
  2096 
  2097 *** ZF ***
  2098 
  2099 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2100 including the First Isomorphism Theorem (on quotienting by the kernel
  2101 of a homomorphism).
  2102 
  2103 * ZF/Simplifier: install second copy of type solver that actually
  2104 makes use of TC rules declared to Isar proof contexts (or locales);
  2105 the old version is still required for ML proof scripts.
  2106 
  2107 
  2108 *** Cube ***
  2109 
  2110 * Converted to Isar theory format; use locales instead of axiomatic
  2111 theories.
  2112 
  2113 
  2114 *** ML ***
  2115 
  2116 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2117 for ||>, ||>>, |>>,
  2118 
  2119 * Pure/library.ML no longer defines its own option datatype, but uses
  2120 that of the SML basis, which has constructors NONE and SOME instead of
  2121 None and Some, as well as exception Option.Option instead of OPTION.
  2122 The functions the, if_none, is_some, is_none have been adapted
  2123 accordingly, while Option.map replaces apsome.
  2124 
  2125 * Pure/library.ML: the exception LIST has been given up in favour of
  2126 the standard exceptions Empty and Subscript, as well as
  2127 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2128 superceded by the standard hd and tl functions etc.
  2129 
  2130 A number of basic list functions are no longer exported to the ML
  2131 toplevel, as they are variants of predefined functions.  The following
  2132 suggests how one can translate existing code:
  2133 
  2134     rev_append xs ys = List.revAppend (xs, ys)
  2135     nth_elem (i, xs) = List.nth (xs, i)
  2136     last_elem xs = List.last xs
  2137     flat xss = List.concat xss
  2138     seq fs = List.app fs
  2139     partition P xs = List.partition P xs
  2140     mapfilter f xs = List.mapPartial f xs
  2141 
  2142 * Pure/library.ML: several combinators for linear functional
  2143 transformations, notably reverse application and composition:
  2144 
  2145   x |> f                f #> g
  2146   (x, y) |-> f          f #-> g
  2147 
  2148 * Pure/library.ML: introduced/changed precedence of infix operators:
  2149 
  2150   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2151   infix 2 ?;
  2152   infix 3 o oo ooo oooo;
  2153   infix 4 ~~ upto downto;
  2154 
  2155 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2156 infix operators.
  2157 
  2158 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2159 fold_map support linear functional transformations and nesting.  For
  2160 example:
  2161 
  2162   fold f [x1, ..., xN] y =
  2163     y |> f x1 |> ... |> f xN
  2164 
  2165   (fold o fold) f [xs1, ..., xsN] y =
  2166     y |> fold f xs1 |> ... |> fold f xsN
  2167 
  2168   fold f [x1, ..., xN] =
  2169     f x1 #> ... #> f xN
  2170 
  2171   (fold o fold) f [xs1, ..., xsN] =
  2172     fold f xs1 #> ... #> fold f xsN
  2173 
  2174 * Pure/library.ML: the following selectors on type 'a option are
  2175 available:
  2176 
  2177   the:               'a option -> 'a  (*partial*)
  2178   these:             'a option -> 'a  where 'a = 'b list
  2179   the_default: 'a -> 'a option -> 'a
  2180   the_list:          'a option -> 'a list
  2181 
  2182 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2183 basic operations for association lists, following natural argument
  2184 order; moreover the explicit equality predicate passed here avoids
  2185 potentially expensive polymorphic runtime equality checks.
  2186 The old functions may be expressed as follows:
  2187 
  2188   assoc = uncurry (AList.lookup (op =))
  2189   assocs = these oo AList.lookup (op =)
  2190   overwrite = uncurry (AList.update (op =)) o swap
  2191 
  2192 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2193 
  2194   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2195   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2196 
  2197 replacing make_keylist and keyfilter (occassionally used)
  2198 Naive rewrites:
  2199 
  2200   make_keylist = AList.make
  2201   keyfilter = AList.find (op =)
  2202 
  2203 * eq_fst and eq_snd now take explicit equality parameter, thus
  2204   avoiding eqtypes. Naive rewrites:
  2205 
  2206     eq_fst = eq_fst (op =)
  2207     eq_snd = eq_snd (op =)
  2208 
  2209 * Removed deprecated apl and apr (rarely used).
  2210   Naive rewrites:
  2211 
  2212     apl (n, op) =>>= curry op n
  2213     apr (op, m) =>>= fn n => op (n, m)
  2214 
  2215 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2216 provides a reasonably efficient light-weight implementation of sets as
  2217 lists.
  2218 
  2219 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2220 few new operations; existing lookup and update are now curried to
  2221 follow natural argument order (for use with fold etc.);
  2222 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2223 
  2224 * Pure/General: output via the Isabelle channels of
  2225 writeln/warning/error etc. is now passed through Output.output, with a
  2226 hook for arbitrary transformations depending on the print_mode
  2227 (cf. Output.add_mode -- the first active mode that provides a output
  2228 function wins).  Already formatted output may be embedded into further
  2229 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2230 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2231 accommodate easy composition of diagnostic messages etc.  Programmers
  2232 rarely need to care about Output.output or Output.raw at all, with
  2233 some notable exceptions: Output.output is required when bypassing the
  2234 standard channels (writeln etc.), or in token translations to produce
  2235 properly formatted results; Output.raw is required when capturing
  2236 already output material that will eventually be presented to the user
  2237 a second time.  For the default print mode, both Output.output and
  2238 Output.raw have no effect.
  2239 
  2240 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2241 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2242 cumulative results are displayed at the end of a batch session.
  2243 
  2244 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2245 replaced by File.platform_path and File.shell_path (with appropriate
  2246 hooks).  This provides a clean interface for unusual systems where the
  2247 internal and external process view of file names are different.
  2248 
  2249 * Pure: more efficient orders for basic syntactic entities: added
  2250 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2251 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2252 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2253 orders now -- potential INCOMPATIBILITY for code that depends on a
  2254 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2255 Library.sort_strings on result).
  2256 
  2257 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2258 fold_types traverse types/terms from left to right, observing natural
  2259 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2260 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2261 
  2262 * Pure: name spaces have been refined, with significant changes of the
  2263 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2264 to extern(_table).  The plain name entry path is superceded by a
  2265 general 'naming' context, which also includes the 'policy' to produce
  2266 a fully qualified name and external accesses of a fully qualified
  2267 name; NameSpace.extend is superceded by context dependent
  2268 Sign.declare_name.  Several theory and proof context operations modify
  2269 the naming context.  Especially note Theory.restore_naming and
  2270 ProofContext.restore_naming to get back to a sane state; note that
  2271 Theory.add_path is no longer sufficient to recover from
  2272 Theory.absolute_path in particular.
  2273 
  2274 * Pure: new flags short_names (default false) and unique_names
  2275 (default true) for controlling output of qualified names.  If
  2276 short_names is set, names are printed unqualified.  If unique_names is
  2277 reset, the name prefix is reduced to the minimum required to achieve
  2278 the original result when interning again, even if there is an overlap
  2279 with earlier declarations.
  2280 
  2281 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2282 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2283 (useful for printing error messages).  INCOMPATIBILITY.
  2284 
  2285 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2286 Theory.theory are now identified, referring to the universal
  2287 Context.theory (see Pure/context.ML).  Actual signature and theory
  2288 content is managed as theory data.  The old code and interfaces were
  2289 spread over many files and structures; the new arrangement introduces
  2290 considerable INCOMPATIBILITY to gain more clarity:
  2291 
  2292   Context -- theory management operations (name, identity, inclusion,
  2293     parents, ancestors, merge, etc.), plus generic theory data;
  2294 
  2295   Sign -- logical signature and syntax operations (declaring consts,
  2296     types, etc.), plus certify/read for common entities;
  2297 
  2298   Theory -- logical theory operations (stating axioms, definitions,
  2299     oracles), plus a copy of logical signature operations (consts,
  2300     types, etc.); also a few basic management operations (Theory.copy,
  2301     Theory.merge, etc.)
  2302 
  2303 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2304 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2305 for convenience -- they merely return the theory.
  2306 
  2307 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2308 
  2309 * Pure: the Isar proof context type is already defined early in Pure
  2310 as Context.proof (note that ProofContext.context and Proof.context are
  2311 aliases, where the latter is the preferred name).  This enables other
  2312 Isabelle components to refer to that type even before Isar is present.
  2313 
  2314 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2315 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2316 any of these kinds.  For example, Sign.intern typeK is now
  2317 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2318 Theory.hide_types.  Also note that former
  2319 Theory.hide_classes/types/consts are now
  2320 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2321 internalize their arguments!  INCOMPATIBILITY.
  2322 
  2323 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2324 datatype thmref (with constructors Name and NameSelection) instead of
  2325 plain string -- INCOMPATIBILITY;
  2326 
  2327 * Pure: cases produced by proof methods specify options, where NONE
  2328 means to remove case bindings -- INCOMPATIBILITY in
  2329 (RAW_)METHOD_CASES.
  2330 
  2331 * Pure: the following operations retrieve axioms or theorems from a
  2332 theory node or theory hierarchy, respectively:
  2333 
  2334   Theory.axioms_of: theory -> (string * term) list
  2335   Theory.all_axioms_of: theory -> (string * term) list
  2336   PureThy.thms_of: theory -> (string * thm) list
  2337   PureThy.all_thms_of: theory -> (string * thm) list
  2338 
  2339 * Pure: print_tac now outputs the goal through the trace channel.
  2340 
  2341 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2342 Reference Toplevel.debug (default false) controls detailed printing
  2343 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2344 controls execution profiling -- set to 1 for time and 2 for space
  2345 (both increase the runtime).
  2346 
  2347 * Isar session: The initial use of ROOT.ML is now always timed,
  2348 i.e. the log will show the actual process times, in contrast to the
  2349 elapsed wall-clock time that the outer shell wrapper produces.
  2350 
  2351 * Simplifier: improved handling of bound variables (nameless
  2352 representation, avoid allocating new strings).  Simprocs that invoke
  2353 the Simplifier recursively should use Simplifier.inherit_bounds to
  2354 avoid local name clashes.  Failure to do so produces warnings
  2355 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2356 for further details.
  2357 
  2358 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2359 bindings for all theorems stored within a given theory; this may help
  2360 in porting non-Isar theories to Isar ones, while keeping ML proof
  2361 scripts for the time being.
  2362 
  2363 * ML operator HTML.with_charset specifies the charset begin used for
  2364 generated HTML files.  For example:
  2365 
  2366   HTML.with_charset "utf-8" use_thy "Hebrew";
  2367   HTML.with_charset "utf-8" use_thy "Chinese";
  2368 
  2369 
  2370 *** System ***
  2371 
  2372 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2373 isabelle, isatool etc.).
  2374 
  2375 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2376 isatool doc, isatool mkdir, display_drafts etc.).
  2377 
  2378 * isatool usedir: option -f allows specification of the ML file to be
  2379 used by Isabelle; default is ROOT.ML.
  2380 
  2381 * New isatool version outputs the version identifier of the Isabelle
  2382 distribution being used.
  2383 
  2384 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2385 (containing Boolean satisfiability problems) into Isabelle/HOL
  2386 theories.
  2387 
  2388 
  2389 
  2390 New in Isabelle2004 (April 2004)
  2391 --------------------------------
  2392 
  2393 *** General ***
  2394 
  2395 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2396   Replaces linorder.ML.
  2397 
  2398 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2399   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2400   (\<a>...\<z>), are now considered normal letters, and can therefore
  2401   be used anywhere where an ASCII letter (a...zA...Z) has until
  2402   now. COMPATIBILITY: This obviously changes the parsing of some
  2403   terms, especially where a symbol has been used as a binder, say
  2404   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2405   as an identifier.  Fix it by inserting a space around former
  2406   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2407   existing theory and ML files.
  2408 
  2409 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2410 
  2411 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2412   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2413   a normal (but invisible) letter. For multiple letter subscripts repeat
  2414   \<^isub> like this: x\<^isub>1\<^isub>2.
  2415 
  2416 * Pure: There are now sub-/superscripts that can span more than one
  2417   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2418   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2419   superscript. The new control characters are not identifier parts.
  2420 
  2421 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2422   content of "..." to the latex file instead of \isacntrl... . The "..."
  2423   may consist of any printable characters excluding the end bracket >.
  2424 
  2425 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2426   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2427   declare constants "final", which prevents their being given a definition
  2428   later.  It is useful for constants whose behaviour is fixed axiomatically
  2429   rather than definitionally, such as the meta-logic connectives.
  2430 
  2431 * Pure: 'instance' now handles general arities with general sorts
  2432   (i.e. intersections of classes),
  2433 
  2434 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2435   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2436   It can be changed to alter the colors/layout of generated pages.
  2437 
  2438 
  2439 *** Isar ***
  2440 
  2441 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2442   cut_tac, subgoal_tac and thin_tac:
  2443   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2444     locales are no longer forced to write Isar proof scripts.
  2445     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2446     emulations.
  2447   - INCOMPATIBILITY: names of variables to be instantiated may no
  2448     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2449     This is consistent with the instantiation attribute "where".
  2450 
  2451 * Attributes "where" and "of":
  2452   - Now take type variables of instantiated theorem into account when reading
  2453     the instantiation string.  This fixes a bug that caused instantiated
  2454     theorems to have too special types in some circumstances.
  2455   - "where" permits explicit instantiations of type variables.
  2456 
  2457 * Calculation commands "moreover" and "also" no longer interfere with
  2458   current facts ("this"), admitting arbitrary combinations with "then"
  2459   and derived forms.
  2460 
  2461 * Locales:
  2462   - Goal statements involving the context element "includes" no longer
  2463     generate theorems with internal delta predicates (those ending on
  2464     "_axioms") in the premise.
  2465     Resolve particular premise with <locale>.intro to obtain old form.
  2466   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2467     specification and "includes" elements in goal statement.
  2468   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2469     [intro?] and [elim?] (respectively) by default.
  2470   - Experimental command for instantiation of locales in proof contexts:
  2471         instantiate <label>[<attrs>]: <loc>
  2472     Instantiates locale <loc> and adds all its theorems to the current context
  2473     taking into account their attributes.  Label and attrs are optional
  2474     modifiers, like in theorem declarations.  If present, names of
  2475     instantiated theorems are qualified with <label>, and the attributes
  2476     <attrs> are applied after any attributes these theorems might have already.
  2477       If the locale has assumptions, a chained fact of the form
  2478     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2479     are derived.  The command does not support old-style locales declared
  2480     with "locale (open)".
  2481       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2482 
  2483 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2484   (Isar) contexts.
  2485 
  2486 
  2487 *** HOL ***
  2488 
  2489 * Proof import: new image HOL4 contains the imported library from
  2490   the HOL4 system with about 2500 theorems. It is imported by
  2491   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2492   can be used like any other Isabelle image.  See
  2493   HOL/Import/HOL/README for more information.
  2494 
  2495 * Simplifier:
  2496   - Much improved handling of linear and partial orders.
  2497     Reasoners for linear and partial orders are set up for type classes
  2498     "linorder" and "order" respectively, and are added to the default simpset
  2499     as solvers.  This means that the simplifier can build transitivity chains
  2500     to solve goals from the assumptions.
  2501   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2502     of blast or auto after simplification become unnecessary because the goal
  2503     is solved by simplification already.
  2504 
  2505 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2506     all proved in axiomatic type classes for semirings, rings and fields.
  2507 
  2508 * Numerics:
  2509   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2510     now formalized using the Ring_and_Field theory mentioned above.
  2511   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2512     than before, because now they are set up once in a generic manner.
  2513   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2514     Look for the general versions in Ring_and_Field (and Power if they concern
  2515     exponentiation).
  2516 
  2517 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2518 
  2519 * Records:
  2520   - Record types are now by default printed with their type abbreviation
  2521     instead of the list of all field types. This can be configured via
  2522     the reference "print_record_type_abbr".
  2523   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2524     (not enabled by default).
  2525   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2526     EX x. x = sel r to True (not enabled by default).
  2527   - Tactic "record_split_simp_tac" to split and simplify records added.
  2528 
  2529 * 'specification' command added, allowing for definition by
  2530   specification.  There is also an 'ax_specification' command that
  2531   introduces the new constants axiomatically.
  2532 
  2533 * arith(_tac) is now able to generate counterexamples for reals as well.
  2534 
  2535 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2536 
  2537 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2538   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2539 
  2540 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2541   matrix theory to linear programming.
  2542 
  2543 * Unions and Intersections:
  2544   The latex output syntax of UN and INT has been changed
  2545   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2546   i.e. the index formulae has become a subscript.
  2547   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2548 
  2549 * Unions and Intersections over Intervals:
  2550   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2551   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2552   like in normal math, and corresponding versions for < and for intersection.
  2553 
  2554 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2555   lexicographic dictonary ordering has been added as "lexord".
  2556 
  2557 * ML: the legacy theory structures Int and List have been removed. They had
  2558   conflicted with ML Basis Library structures having the same names.
  2559 
  2560 * 'refute' command added to search for (finite) countermodels.  Only works
  2561   for a fragment of HOL.  The installation of an external SAT solver is
  2562   highly recommended.  See "HOL/Refute.thy" for details.
  2563 
  2564 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2565   formulae under an assignment of free variables to random values.
  2566   In contrast to 'refute', it can deal with inductive datatypes,
  2567   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2568   for examples.
  2569 
  2570 
  2571 *** HOLCF ***
  2572 
  2573 * Streams now come with concatenation and are part of the HOLCF image
  2574 
  2575 
  2576 
  2577 New in Isabelle2003 (May 2003)
  2578 ------------------------------
  2579 
  2580 *** General ***
  2581 
  2582 * Provers/simplifier:
  2583 
  2584   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2585     Assumptions are now subject to complete mutual simplification,
  2586     not just from left to right. The simplifier now preserves
  2587     the order of assumptions.
  2588 
  2589     Potential INCOMPATIBILITY:
  2590 
  2591     -- simp sometimes diverges where the old version did
  2592        not, e.g. invoking simp on the goal
  2593 
  2594         [| P (f x); y = x; f x = f y |] ==> Q
  2595 
  2596        now gives rise to the infinite reduction sequence
  2597 
  2598         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2599 
  2600        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2601        kind of problem.
  2602 
  2603     -- Tactics combining classical reasoner and simplification (such as auto)
  2604        are also affected by this change, because many of them rely on
  2605        simp. They may sometimes diverge as well or yield a different numbers
  2606        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2607        in case of problems. Sometimes subsequent calls to the classical
  2608        reasoner will fail because a preceeding call to the simplifier too
  2609        eagerly simplified the goal, e.g. deleted redundant premises.
  2610 
  2611   - The simplifier trace now shows the names of the applied rewrite rules
  2612 
  2613   - You can limit the number of recursive invocations of the simplifier
  2614     during conditional rewriting (where the simplifie tries to solve the
  2615     conditions before applying the rewrite rule):
  2616     ML "simp_depth_limit := n"
  2617     where n is an integer. Thus you can force termination where previously
  2618     the simplifier would diverge.
  2619 
  2620   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2621 
  2622   - No longer aborts on failed congruence proof.  Instead, the
  2623     congruence is ignored.
  2624 
  2625 * Pure: New generic framework for extracting programs from constructive
  2626   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2627   as HOL/Extraction for some case studies.
  2628 
  2629 * Pure: The main goal of the proof state is no longer shown by default, only
  2630 the subgoals. This behaviour is controlled by a new flag.
  2631    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2632 (ML: Proof.show_main_goal).
  2633 
  2634 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2635 rules whose conclusion matches subgoal 1:
  2636       PG menu: Isabelle/Isar -> Show me -> matching rules
  2637 The rules are ordered by how closely they match the subgoal.
  2638 In particular, rules that solve a subgoal outright are displayed first
  2639 (or rather last, the way they are printed).
  2640 (ML: ProofGeneral.print_intros())
  2641 
  2642 * Pure: New flag trace_unify_fail causes unification to print
  2643 diagnostic information (PG: in trace buffer) when it fails. This is
  2644 useful for figuring out why single step proofs like rule, erule or
  2645 assumption failed.
  2646 
  2647 * Pure: Locale specifications now produce predicate definitions
  2648 according to the body of text (covering assumptions modulo local
  2649 definitions); predicate "loc_axioms" covers newly introduced text,
  2650 while "loc" is cumulative wrt. all included locale expressions; the
  2651 latter view is presented only on export into the global theory
  2652 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2653 on the old view without predicates;
  2654 
  2655 * Pure: predefined locales "var" and "struct" are useful for sharing
  2656 parameters (as in CASL, for example); just specify something like
  2657 ``var x + var y + struct M'' as import;
  2658 
  2659 * Pure: improved thms_containing: proper indexing of facts instead of
  2660 raw theorems; check validity of results wrt. current name space;
  2661 include local facts of proof configuration (also covers active
  2662 locales), cover fixed variables in index; may use "_" in term
  2663 specification; an optional limit for the number of printed facts may
  2664 be given (the default is 40);
  2665 
  2666 * Pure: disallow duplicate fact bindings within new-style theory files
  2667 (batch-mode only);
  2668 
  2669 * Provers: improved induct method: assumptions introduced by case
  2670 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2671 the goal statement); "foo" still refers to all facts collectively;
  2672 
  2673 * Provers: the function blast.overloaded has been removed: all constants
  2674 are regarded as potentially overloaded, which improves robustness in exchange
  2675 for slight decrease in efficiency;
  2676 
  2677 * Provers/linorder: New generic prover for transitivity reasoning over
  2678 linear orders.  Note: this prover is not efficient!
  2679 
  2680 * Isar: preview of problems to finish 'show' now produce an error
  2681 rather than just a warning (in interactive mode);
  2682 
  2683 
  2684 *** HOL ***
  2685 
  2686 * arith(_tac)
  2687 
  2688  - Produces a counter example if it cannot prove a goal.
  2689    Note that the counter example may be spurious if the goal is not a formula
  2690    of quantifier-free linear arithmetic.
  2691    In ProofGeneral the counter example appears in the trace buffer.
  2692 
  2693  - Knows about div k and mod k where k is a numeral of type nat or int.
  2694 
  2695  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2696    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2697    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2698 
  2699 * simp's arithmetic capabilities have been enhanced a bit: it now
  2700 takes ~= in premises into account (by performing a case split);
  2701 
  2702 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2703 are distributed over a sum of terms;
  2704 
  2705 * New tactic "trans_tac" and method "trans" instantiate
  2706 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2707 "<=", "<" and "=").
  2708 
  2709 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2710 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2711 
  2712 * 'typedef' command has new option "open" to suppress the set
  2713 definition;
  2714 
  2715 * functions Min and Max on finite sets have been introduced (theory
  2716 Finite_Set);
  2717 
  2718 * attribute [symmetric] now works for relations as well; it turns
  2719 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2720 
  2721 * induct over a !!-quantified statement (say !!x1..xn):
  2722   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2723 
  2724 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2725 %x. None. Warning: empty_def now refers to the previously hidden definition
  2726 of the empty set.
  2727 
  2728 * Algebra: formalization of classical algebra.  Intended as base for
  2729 any algebraic development in Isabelle.  Currently covers group theory
  2730 (up to Sylow's theorem) and ring theory (Universal Property of
  2731 Univariate Polynomials).  Contributions welcome;
  2732 
  2733 * GroupTheory: deleted, since its material has been moved to Algebra;
  2734 
  2735 * Complex: new directory of the complex numbers with numeric constants,
  2736 nonstandard complex numbers, and some complex analysis, standard and
  2737 nonstandard (Jacques Fleuriot);
  2738 
  2739 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2740 
  2741 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2742 Fleuriot);
  2743 
  2744 * Real/HahnBanach: updated and adapted to locales;
  2745 
  2746 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2747 Gray and Kramer);
  2748 
  2749 * UNITY: added the Meier-Sanders theory of progress sets;
  2750 
  2751 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2752 as abstract algorithms, instantiated to the JVM;
  2753 
  2754 * Bali: Java source language formalization. Type system, operational
  2755 semantics, axiomatic semantics. Supported language features:
  2756 classes, interfaces, objects,virtual methods, static methods,
  2757 static/instance fields, arrays, access modifiers, definite
  2758 assignment, exceptions.
  2759 
  2760 
  2761 *** ZF ***
  2762 
  2763 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2764 universe, etc.);
  2765 
  2766 * Main ZF: virtually all theories converted to new-style format;
  2767 
  2768 
  2769 *** ML ***
  2770 
  2771 * Pure: Tactic.prove provides sane interface for internal proofs;
  2772 omits the infamous "standard" operation, so this is more appropriate
  2773 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2774 
  2775 * Pure: improved error reporting of simprocs;
  2776 
  2777 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2778 up simprocs;
  2779 
  2780 
  2781 *** Document preparation ***
  2782 
  2783 * uses \par instead of \\ for line breaks in theory text. This may
  2784 shift some page breaks in large documents. To get the old behaviour
  2785 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2786 
  2787 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2788 other packages
  2789 
  2790 * \<euro> now needs package babel/greek instead of marvosym (which
  2791 broke \Rightarrow)
  2792 
  2793 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2794 textcomp package)
  2795 
  2796 
  2797 
  2798 New in Isabelle2002 (March 2002)
  2799 --------------------------------
  2800 
  2801 *** Document preparation ***
  2802 
  2803 * greatly simplified document preparation setup, including more
  2804 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2805 instructive isatool mkdir; users should basically be able to get
  2806 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2807 users may run a separate document processing stage manually like this:
  2808 "isatool usedir -D output HOL Test && isatool document Test/output";
  2809 
  2810 * theory dependency graph may now be incorporated into documents;
  2811 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2812 with \includegraphics of LaTeX;
  2813 
  2814 * proper spacing of consecutive markup elements, especially text
  2815 blocks after section headings;
  2816 
  2817 * support bold style (for single symbols only), input syntax is like
  2818 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2819 
  2820 * \<bullet> is now output as bold \cdot by default, which looks much
  2821 better in printed text;
  2822 
  2823 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2824 note that these symbols are currently unavailable in Proof General /
  2825 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2826 
  2827 * isatool latex no longer depends on changed TEXINPUTS, instead
  2828 isatool document copies the Isabelle style files to the target
  2829 location;
  2830 
  2831 
  2832 *** Isar ***
  2833 
  2834 * Pure/Provers: improved proof by cases and induction;
  2835   - 'case' command admits impromptu naming of parameters (such as
  2836     "case (Suc n)");
  2837   - 'induct' method divinates rule instantiation from the inductive
  2838     claim; no longer requires excessive ?P bindings for proper
  2839     instantiation of cases;
  2840   - 'induct' method properly enumerates all possibilities of set/type
  2841     rules; as a consequence facts may be also passed through *type*
  2842     rules without further ado;
  2843   - 'induct' method now derives symbolic cases from the *rulified*
  2844     rule (before it used to rulify cases stemming from the internal
  2845     atomized version); this means that the context of a non-atomic
  2846     statement becomes is included in the hypothesis, avoiding the
  2847     slightly cumbersome show "PROP ?case" form;
  2848   - 'induct' may now use elim-style induction rules without chaining
  2849     facts, using ``missing'' premises from the goal state; this allows
  2850     rules stemming from inductive sets to be applied in unstructured
  2851     scripts, while still benefitting from proper handling of non-atomic
  2852     statements; NB: major inductive premises need to be put first, all
  2853     the rest of the goal is passed through the induction;
  2854   - 'induct' proper support for mutual induction involving non-atomic
  2855     rule statements (uses the new concept of simultaneous goals, see
  2856     below);
  2857   - append all possible rule selections, but only use the first
  2858     success (no backtracking);
  2859   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2860   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2861   - added 'print_induct_rules' (covered by help item in recent Proof
  2862     General versions);
  2863   - moved induct/cases attributes to Pure, methods to Provers;
  2864   - generic method setup instantiated for FOL and HOL;
  2865 
  2866 * Pure: support multiple simultaneous goal statements, for example
  2867 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2868 meta-level mechanism, this acts as if several individual goals had
  2869 been stated separately; in particular common proof methods need to be
  2870 repeated in order to cover all claims; note that a single elimination
  2871 step is *not* sufficient to establish the two conjunctions, so this
  2872 fails:
  2873 
  2874   assume "A & B" then have A and B ..   (*".." fails*)
  2875 
  2876 better use "obtain" in situations as above; alternative refer to
  2877 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2878 
  2879 * Pure: proper integration with ``locales''; unlike the original
  2880 version by Florian Kammller, Isar locales package high-level proof
  2881 contexts rather than raw logical ones (e.g. we admit to include
  2882 attributes everywhere); operations on locales include merge and
  2883 rename; support for implicit arguments (``structures''); simultaneous
  2884 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2885 some examples;
  2886 
  2887 * Pure: the following commands have been ``localized'', supporting a
  2888 target locale specification "(in name)": 'lemma', 'theorem',
  2889 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2890 stored both within the locale and at the theory level (exported and
  2891 qualified by the locale name);
  2892 
  2893 * Pure: theory goals may now be specified in ``long'' form, with
  2894 ad-hoc contexts consisting of arbitrary locale elements. for example
  2895 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2896 definitions may be given, too); the result is a meta-level rule with
  2897 the context elements being discharged in the obvious way;
  2898 
  2899 * Pure: new proof command 'using' allows to augment currently used
  2900 facts after a goal statement ('using' is syntactically analogous to
  2901 'apply', but acts on the goal's facts only); this allows chained facts
  2902 to be separated into parts given before and after a claim, as in
  2903 ``from a and b have C using d and e <proof>'';
  2904 
  2905 * Pure: renamed "antecedent" case to "rule_context";
  2906 
  2907 * Pure: new 'judgment' command records explicit information about the
  2908 object-logic embedding (used by several tools internally); no longer
  2909 use hard-wired "Trueprop";
  2910 
  2911 * Pure: added 'corollary' command;
  2912 
  2913 * Pure: fixed 'token_translation' command;
  2914 
  2915 * Pure: removed obsolete 'exported' attribute;
  2916 
  2917 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2918 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2919 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2920 
  2921 * Pure: method 'atomize' presents local goal premises as object-level
  2922 statements (atomic meta-level propositions); setup controlled via
  2923 rewrite rules declarations of 'atomize' attribute; example
  2924 application: 'induct' method with proper rule statements in improper
  2925 proof *scripts*;
  2926 
  2927 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2928 now consider the syntactic context of assumptions, giving a better
  2929 chance to get type-inference of the arguments right (this is
  2930 especially important for locales);
  2931 
  2932 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2933 mode;
  2934 
  2935 * Pure/obtain: the formal conclusion "thesis", being marked as
  2936 ``internal'', may no longer be reference directly in the text;
  2937 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2938 situations;
  2939 
  2940 * Pure: generic 'sym' attribute which declares a rule both as pure
  2941 'elim?' and for the 'symmetric' operation;
  2942 
  2943 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2944 text; the fixed correlation with particular command syntax has been
  2945 discontinued;
  2946 
  2947 * Pure: new method 'rules' is particularly well-suited for proof
  2948 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2949 but often produces more compact proof terms with less detours;
  2950 
  2951 * Pure/Provers/classical: simplified integration with pure rule
  2952 attributes and methods; the classical "intro?/elim?/dest?"
  2953 declarations coincide with the pure ones; the "rule" method no longer
  2954 includes classically swapped intros; "intro" and "elim" methods no
  2955 longer pick rules from the context; also got rid of ML declarations
  2956 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2957 INCOMPATIBILITY;
  2958 
  2959 * Provers/classical: attribute 'swapped' produces classical inversions
  2960 of introduction rules;
  2961 
  2962 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2963 rules instead of full simplifier context; 'iff' attribute handles
  2964 conditional rules;
  2965 
  2966 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2967 
  2968 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2969 "(permissive)" option to recover old behavior;
  2970 
  2971 * HOL: 'inductive' no longer features separate (collective) attributes
  2972 for 'intros' (was found too confusing);
  2973 
  2974 * HOL: properly declared induction rules less_induct and
  2975 wf_induct_rule;
  2976 
  2977 
  2978 *** HOL ***
  2979 
  2980 * HOL: moved over to sane numeral syntax; the new policy is as
  2981 follows:
  2982 
  2983   - 0 and 1 are polymorphic constants, which are defined on any
  2984   numeric type (nat, int, real etc.);
  2985 
  2986   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2987   binary representation internally;
  2988 
  2989   - type nat has special constructor Suc, and generally prefers Suc 0
  2990   over 1::nat and Suc (Suc 0) over 2::nat;
  2991 
  2992 This change may cause significant problems of INCOMPATIBILITY; here
  2993 are some hints on converting existing sources:
  2994 
  2995   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2996   entities, so expressions involving "-" (unary or binary minus) need
  2997   to be spaced properly;
  2998 
  2999   - existing occurrences of "1" may need to be constraint "1::nat" or
  3000   even replaced by Suc 0; similar for old "2";
  3001 
  3002   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3003 
  3004   - remove all special provisions on numerals in proofs;
  3005 
  3006 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3007 representation (depends on bin_arith_simps in the default context);
  3008 
  3009 * HOL: symbolic syntax for x^2 (numeral 2);
  3010 
  3011 * HOL: the class of all HOL types is now called "type" rather than
  3012 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3013 in axclass/classes, instance/arities, and (usually rare) occurrences
  3014 in typings (of consts etc.); internally the class is called
  3015 "HOL.type", ML programs should refer to HOLogic.typeS;
  3016 
  3017 * HOL/record package improvements:
  3018   - new derived operations "fields" to build a partial record section,
  3019     "extend" to promote a fixed record to a record scheme, and
  3020     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3021     declared as simp by default;
  3022   - shared operations ("more", "fields", etc.) now need to be always
  3023     qualified) --- potential INCOMPATIBILITY;
  3024   - removed "make_scheme" operations (use "make" with "extend") --
  3025     INCOMPATIBILITY;
  3026   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3027   - provides cases/induct rules for use with corresponding Isar
  3028     methods (for concrete records, record schemes, concrete more
  3029     parts, and schematic more parts -- in that order);
  3030   - internal definitions directly based on a light-weight abstract
  3031     theory of product types over typedef rather than datatype;
  3032 
  3033 * HOL: generic code generator for generating executable ML code from
  3034 specifications; specific support for HOL constructs such as inductive
  3035 datatypes and sets, as well as recursive functions; can be invoked
  3036 via 'generate_code' theory section;
  3037 
  3038 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3039 
  3040 * HOL: consolidated and renamed several theories.  In particular:
  3041         Ord.thy has been absorbed into HOL.thy
  3042         String.thy has been absorbed into List.thy
  3043 
  3044 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3045 (beware of argument permutation!);
  3046 
  3047 * HOL: linorder_less_split superseded by linorder_cases;
  3048 
  3049 * HOL/List: "nodups" renamed to "distinct";
  3050 
  3051 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3052 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3053   - Ex_def has changed, now need to use some_eq_ex
  3054 
  3055 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3056 in this (rare) case use:
  3057 
  3058   delSWrapper "split_all_tac"
  3059   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3060 
  3061 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3062 MAY FAIL;
  3063 
  3064 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3065 Isabelle's type classes, ^ on functions and relations has too general
  3066 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3067 necessary to attach explicit type constraints;
  3068 
  3069 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3070 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3071 renamed accordingly (eg "compI" -> "rel_compI").
  3072 
  3073 * HOL: syntax translations now work properly with numerals and records
  3074 expressions;
  3075 
  3076 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3077 of "lam" -- INCOMPATIBILITY;
  3078 
  3079 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3080 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3081 renamed "Product_Type.unit";
  3082 
  3083 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3084 
  3085 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3086 the "cases" method);
  3087 
  3088 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3089 Florian Kammller);
  3090 
  3091 * HOL/IMP: updated and converted to new-style theory format; several
  3092 parts turned into readable document, with proper Isar proof texts and
  3093 some explanations (by Gerwin Klein);
  3094 
  3095 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3096 
  3097 * HOL-Hyperreal is now a logic image;
  3098 
  3099 
  3100 *** HOLCF ***
  3101 
  3102 * Isar: consts/constdefs supports mixfix syntax for continuous
  3103 operations;
  3104 
  3105 * Isar: domain package adapted to new-style theory format, e.g. see
  3106 HOLCF/ex/Dnat.thy;
  3107 
  3108 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3109 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3110 lift.induct_tac, always use UU instead of Undef;
  3111 
  3112 * HOLCF/IMP: updated and converted to new-style theory;
  3113 
  3114 
  3115 *** ZF ***
  3116 
  3117 * Isar: proper integration of logic-specific tools and packages,
  3118 including theory commands '(co)inductive', '(co)datatype',
  3119 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3120 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3121 
  3122 * theory Main no longer includes AC; for the Axiom of Choice, base
  3123 your theory on Main_ZFC;
  3124 
  3125 * the integer library now covers quotients and remainders, with many
  3126 laws relating division to addition, multiplication, etc.;
  3127 
  3128 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3129 typeless version of the formalism;
  3130 
  3131 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3132 format;
  3133 
  3134 * ZF/Induct: new directory for examples of inductive definitions,
  3135 including theory Multiset for multiset orderings; converted to
  3136 new-style theory format;
  3137 
  3138 * ZF: many new theorems about lists, ordinals, etc.;
  3139 
  3140 
  3141 *** General ***
  3142 
  3143 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3144 variable proof controls level of detail: 0 = no proofs (only oracle
  3145 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3146 also ref manual for further ML interfaces;
  3147 
  3148 * Pure/axclass: removed obsolete ML interface
  3149 goal_subclass/goal_arity;
  3150 
  3151 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3152 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3153 separate tokens, so expressions involving minus need to be spaced
  3154 properly;
  3155 
  3156 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3157 rather than "infixl" or "infixr";
  3158 
  3159 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3160 sort constraint specifications in type inference; e.g. "x::_::foo"
  3161 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3162 type variable);
  3163 
  3164 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3165 control output of nested => (types); the default behavior is
  3166 "type_brackets";
  3167 
  3168 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3169 tokens into AST constants;
  3170 
  3171 * Pure/syntax: prefer later declarations of translations and print
  3172 translation functions; potential INCOMPATIBILITY: need to reverse
  3173 multiple declarations for same syntax element constant;
  3174 
  3175 * Pure/show_hyps reset by default (in accordance to existing Isar
  3176 practice);
  3177 
  3178 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3179 addSafter;
  3180 
  3181 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3182 as well;
  3183 
  3184 * system: tested support for MacOS X; should be able to get Isabelle +
  3185 Proof General to work in a plain Terminal after installing Poly/ML
  3186 (e.g. from the Isabelle distribution area) and GNU bash alone
  3187 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3188 support requires further installations, e.g. from
  3189 http://fink.sourceforge.net/);
  3190 
  3191 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3192 
  3193 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3194 of 40 MB), cf. ML_OPTIONS;
  3195 
  3196 * system: Proof General keywords specification is now part of the
  3197 Isabelle distribution (see etc/isar-keywords.el);
  3198 
  3199 * system: support for persistent Proof General sessions (refrain from
  3200 outdating all loaded theories on startup); user may create writable
  3201 logic images like this: ``isabelle -q HOL Test'';
  3202 
  3203 * system: smart selection of Isabelle process versus Isabelle
  3204 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3205 run both "isabelle" and "Isabelle" even if file names are badly
  3206 damaged (executable inspects the case of the first letter of its own
  3207 name); added separate "isabelle-process" and "isabelle-interface";
  3208 
  3209 * system: refrain from any attempt at filtering input streams; no
  3210 longer support ``8bit'' encoding of old isabelle font, instead proper
  3211 iso-latin characters may now be used; the related isatools
  3212 "symbolinput" and "nonascii" have disappeared as well;
  3213 
  3214 * system: removed old "xterm" interface (the print modes "xterm" and
  3215 "xterm_color" are still available for direct use in a suitable
  3216 terminal);
  3217 
  3218 
  3219 
  3220 New in Isabelle99-2 (February 2001)
  3221 -----------------------------------
  3222 
  3223 *** Overview of INCOMPATIBILITIES ***
  3224 
  3225 * HOL: please note that theories in the Library and elsewhere often use the
  3226 new-style (Isar) format; to refer to their theorems in an ML script you must
  3227 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3228 
  3229 * HOL: inductive package no longer splits induction rule aggressively,
  3230 but only as far as specified by the introductions given; the old
  3231 format may be recovered via ML function complete_split_rule or attribute
  3232 'split_rule (complete)';
  3233 
  3234 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3235 gfp_Tarski to gfp_unfold;
  3236 
  3237 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3238 
  3239 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3240 relation); infix "^^" has been renamed "``"; infix "``" has been
  3241 renamed "`"; "univalent" has been renamed "single_valued";
  3242 
  3243 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3244 operation;
  3245 
  3246 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3247 
  3248 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3249 
  3250 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3251 consequence, it is no longer monotonic wrt. the local goal context
  3252 (which is now passed through the inductive cases);
  3253 
  3254 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3255 \<gg> to \<ggreater>;
  3256 
  3257 
  3258 *** Document preparation ***
  3259 
  3260 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3261 available: are "it" for near math-mode best-style output, "sl" for
  3262 slanted text style, and "tt" for plain type-writer; if no
  3263 \isabellestyle command is given, output is according to slanted
  3264 type-writer);
  3265 
  3266 * support sub/super scripts (for single symbols only), input syntax is
  3267 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3268 
  3269 * some more standard symbols; see Appendix A of the system manual for
  3270 the complete list of symbols defined in isabellesym.sty;
  3271 
  3272 * improved isabelle style files; more abstract symbol implementation
  3273 (should now use \isamath{...} and \isatext{...} in custom symbol
  3274 definitions);
  3275 
  3276 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3277 state; Note that presentation of goal states does not conform to
  3278 actual human-readable proof documents.  Please do not include goal
  3279 states into document output unless you really know what you are doing!
  3280 
  3281 * proper indentation of antiquoted output with proportional LaTeX
  3282 fonts;
  3283 
  3284 * no_document ML operator temporarily disables LaTeX document
  3285 generation;
  3286 
  3287 * isatool unsymbolize tunes sources for plain ASCII communication;
  3288 
  3289 
  3290 *** Isar ***
  3291 
  3292 * Pure: Isar now suffers initial goal statements to contain unbound
  3293 schematic variables (this does not conform to actual readable proof
  3294 documents, due to unpredictable outcome and non-compositional proof
  3295 checking); users who know what they are doing may use schematic goals
  3296 for Prolog-style synthesis of proven results;
  3297 
  3298 * Pure: assumption method (an implicit finishing) now handles actual
  3299 rules as well;
  3300 
  3301 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3302 initial goal, declare "that" only as Pure intro (only for single
  3303 steps); the "that" rule assumption may now be involved in implicit
  3304 finishing, thus ".." becomes a feasible for trivial obtains;
  3305 
  3306 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3307 instance proofs may be performed by "..";
  3308 
  3309 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3310 statements as well;
  3311 
  3312 * Pure: more robust selection of calculational rules;
  3313 
  3314 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3315 rule (as well as the assumption rule);
  3316 
  3317 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3318 lemmas, using the graph browser tool;
  3319 
  3320 * Pure: predict failure of "show" in interactive mode;
  3321 
  3322 * Pure: 'thms_containing' now takes actual terms as arguments;
  3323 
  3324 * HOL: improved method 'induct' --- now handles non-atomic goals
  3325 (potential INCOMPATIBILITY); tuned error handling;
  3326 
  3327 * HOL: cases and induct rules now provide explicit hints about the
  3328 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3329 any remaining facts are inserted into the goal verbatim;
  3330 
  3331 * HOL: local contexts (aka cases) may now contain term bindings as
  3332 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3333 the result to be shown in each case;
  3334 
  3335 * HOL: added 'recdef_tc' command;
  3336 
  3337 * isatool convert assists in eliminating legacy ML scripts;
  3338 
  3339 
  3340 *** HOL ***
  3341 
  3342 * HOL/Library: a collection of generic theories to be used together
  3343 with main HOL; the theory loader path already includes this directory
  3344 by default; the following existing theories have been moved here:
  3345 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3346 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3347 
  3348 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3349 modelling and verification task performed in Isabelle/HOL +
  3350 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3351 
  3352 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3353 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3354 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3355 'domain', this makes the theory consistent with mathematical
  3356 literature;
  3357 
  3358 * HOL basics: added overloaded operations "inverse" and "divide"
  3359 (infix "/"), syntax for generic "abs" operation, generic summation
  3360 operator \<Sum>;
  3361 
  3362 * HOL/typedef: simplified package, provide more useful rules (see also
  3363 HOL/subset.thy);
  3364 
  3365 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3366 now expressed as a proper nested rule (old-style tactic scripts may
  3367 require atomize_strip_tac to cope with non-atomic premises);
  3368 
  3369 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3370 to "split_conv" (old name still available for compatibility);
  3371 
  3372 * HOL: improved concrete syntax for strings (e.g. allows translation
  3373 rules with string literals);
  3374 
  3375 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3376  and Fleuriot's mechanization of analysis, including the transcendental
  3377  functions for the reals;
  3378 
  3379 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3380 
  3381 
  3382 *** CTT ***
  3383 
  3384 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3385 "lam" is displayed as TWO lambda-symbols
  3386 
  3387 * CTT: theory Main now available, containing everything (that is, Bool
  3388 and Arith);
  3389 
  3390 
  3391 *** General ***
  3392 
  3393 * Pure: the Simplifier has been implemented properly as a derived rule
  3394 outside of the actual kernel (at last!); the overall performance
  3395 penalty in practical applications is about 50%, while reliability of
  3396 the Isabelle inference kernel has been greatly improved;
  3397 
  3398 * print modes "brackets" and "no_brackets" control output of nested =>
  3399 (types) and ==> (props); the default behaviour is "brackets";
  3400 
  3401 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3402 as assumptions as well;
  3403 
  3404 * system: support Poly/ML 4.0;
  3405 
  3406 * system: isatool install handles KDE version 1 or 2;
  3407 
  3408 
  3409 
  3410 New in Isabelle99-1 (October 2000)
  3411 ----------------------------------
  3412 
  3413 *** Overview of INCOMPATIBILITIES ***
  3414 
  3415 * HOL: simplification of natural numbers is much changed; to partly
  3416 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3417 issue the following ML commands:
  3418 
  3419   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3420   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3421 
  3422 * HOL: simplification no longer dives into case-expressions; this is
  3423 controlled by "t.weak_case_cong" for each datatype t;
  3424 
  3425 * HOL: nat_less_induct renamed to less_induct;
  3426 
  3427 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3428 fixsome to patch .thy and .ML sources automatically;
  3429 
  3430   select_equality  -> some_equality
  3431   select_eq_Ex     -> some_eq_ex
  3432   selectI2EX       -> someI2_ex
  3433   selectI2         -> someI2
  3434   selectI          -> someI
  3435   select1_equality -> some1_equality
  3436   Eps_sym_eq       -> some_sym_eq_trivial
  3437   Eps_eq           -> some_eq_trivial
  3438 
  3439 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3440 
  3441 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3442 instead);
  3443 
  3444 * HOL: the recursion equations generated by 'recdef' are now called
  3445 f.simps instead of f.rules;
  3446 
  3447 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3448 
  3449 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3450 sometimes be needed;
  3451 
  3452 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3453 
  3454 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3455 
  3456 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3457 product is now "<*>" instead of "Times"; the lexicographic product is
  3458 now "<*lex*>" instead of "**";
  3459 
  3460 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3461 of main HOL, but was unused); better use HOL's datatype package;
  3462 
  3463 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3464 the old syntax may be recovered as follows:
  3465 
  3466   syntax (symbols)
  3467     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3468       (infixl "\\<oplus>" 100)
  3469 
  3470 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3471 
  3472 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3473 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3474 internally;
  3475 
  3476 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3477 changed from A/r to A//r;
  3478 
  3479 * ZF: new treatment of arithmetic (nat & int) may break some old
  3480 proofs;
  3481 
  3482 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3483 rulify -> rule_format, elimify -> elim_format, ...);
  3484 
  3485 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3486 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3487 should have to change intro!! to intro? only); replaced "delrule" by
  3488 "rule del";
  3489 
  3490 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3491 
  3492 * Provers: strengthened force_tac by using new first_best_tac;
  3493 
  3494 * LaTeX document preparation: several changes of isabelle.sty (see
  3495 lib/texinputs);
  3496 
  3497 
  3498 *** Document preparation ***
  3499 
  3500 * formal comments (text blocks etc.) in new-style theories may now
  3501 contain antiquotations of thm/prop/term/typ/text to be presented
  3502 according to latex print mode; concrete syntax is like this:
  3503 @{term[show_types] "f(x) = a + x"};
  3504 
  3505 * isatool mkdir provides easy setup of Isabelle session directories,
  3506 including proper document sources;
  3507 
  3508 * generated LaTeX sources are now deleted after successful run
  3509 (isatool document -c); may retain a copy somewhere else via -D option
  3510 of isatool usedir;
  3511 
  3512 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3513 style files, achieving self-contained LaTeX sources and simplifying
  3514 LaTeX debugging;
  3515 
  3516 * old-style theories now produce (crude) LaTeX output as well;
  3517 
  3518 * browser info session directories are now self-contained (may be put
  3519 on WWW server seperately); improved graphs of nested sessions; removed
  3520 graph for 'all sessions';
  3521 
  3522 * several improvements in isabelle style files; \isabellestyle{it}
  3523 produces fake math mode output; \isamarkupheader is now \section by
  3524 default; see lib/texinputs/isabelle.sty etc.;
  3525 
  3526 
  3527 *** Isar ***
  3528 
  3529 * Isar/Pure: local results and corresponding term bindings are now
  3530 subject to Hindley-Milner polymorphism (similar to ML); this
  3531 accommodates incremental type-inference very nicely;
  3532 
  3533 * Isar/Pure: new derived language element 'obtain' supports
  3534 generalized existence reasoning;
  3535 
  3536 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3537 support accumulation of results, without applying any rules yet;
  3538 useful to collect intermediate results without explicit name
  3539 references, and for use with transitivity rules with more than 2
  3540 premises;
  3541 
  3542 * Isar/Pure: scalable support for case-analysis type proofs: new
  3543 'case' language element refers to local contexts symbolically, as
  3544 produced by certain proof methods; internally, case names are attached
  3545 to theorems as "tags";
  3546 
  3547 * Isar/Pure: theory command 'hide' removes declarations from
  3548 class/type/const name spaces;
  3549 
  3550 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3551 indicate potential overloading;
  3552 
  3553 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3554 
  3555 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3556 "{a,b,c}" instead of {a,b,c};
  3557 
  3558 * Isar/Pure now provides its own version of intro/elim/dest
  3559 attributes; useful for building new logics, but beware of confusion
  3560 with the version in Provers/classical;
  3561 
  3562 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3563 case name 'antecedent';
  3564 
  3565 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3566 to the current context is now done automatically);
  3567 
  3568 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3569 for definining proof methods in ML;
  3570 
  3571 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3572 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3573 most cases, one should have to change intro!! to intro? only);
  3574 replaced "delrule" by "rule del";
  3575 
  3576 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3577 'symmetric' attribute (the latter supercedes [RS sym]);
  3578 
  3579 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3580 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3581 well (including splits);
  3582 
  3583 * Isar/Provers: Simplifier and Classical methods now support all kind
  3584 of modifiers used in the past, including 'cong', 'iff', etc.
  3585 
  3586 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3587 of Simplifier and Classical reasoner);
  3588 
  3589 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3590 now support named cases; major packages (inductive, datatype, primrec,
  3591 recdef) support case names and properly name parameters;
  3592 
  3593 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3594 monotonicity conditions are extracted to be proven at end of
  3595 calculations;
  3596 
  3597 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3598 method anyway;
  3599 
  3600 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3601 split_if split_if_asm; datatype package provides theorems foo.splits =
  3602 foo.split foo.split_asm for each datatype;
  3603 
  3604 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3605 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3606 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3607 use "(cases (simplified))" method in proper proof texts);
  3608 
  3609 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3610 
  3611 * Isar: names of theorems etc. may be natural numbers as well;
  3612 
  3613 * Isar: 'pr' command: optional arguments for goals_limit and
  3614 ProofContext.prems_limit; no longer prints theory contexts, but only
  3615 proof states;
  3616 
  3617 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3618 additional print modes to be specified; e.g. "pr(latex)" will print
  3619 proof state according to the Isabelle LaTeX style;
  3620 
  3621 * Isar: improved support for emulating tactic scripts, including proof
  3622 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3623 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3624 (for HOL datatypes);
  3625 
  3626 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3627 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3628 'proof method scripts' have to be in depth-first order;
  3629 
  3630 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3631 
  3632 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3633 should instead use individual commands for printing items
  3634 (print_commands, print_methods etc.);
  3635 
  3636 * Isar: added 'nothing' --- the empty list of theorems;
  3637 
  3638 
  3639 *** HOL ***
  3640 
  3641 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3642 corresponding virtual machine and a specification of its bytecode
  3643 verifier and a lightweight bytecode verifier, including proofs of
  3644 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3645 Cornelia Pusch (see also the homepage of project Bali at
  3646 http://isabelle.in.tum.de/Bali/);
  3647 
  3648 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3649 Clemens Ballarin;
  3650 
  3651 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3652 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3653 Rasmussen;
  3654 
  3655 * HOL/Lattice: fundamental concepts of lattice theory and order
  3656 structures, including duals, properties of bounds versus algebraic
  3657 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3658 Theorem for complete lattices etc.; may also serve as a demonstration
  3659 for abstract algebraic reasoning using axiomatic type classes, and
  3660 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3661 
  3662 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3663 von Oheimb;
  3664 
  3665 * HOL/IMPP: extension of IMP with local variables and mutually
  3666 recursive procedures, by David von Oheimb;
  3667 
  3668 * HOL/Lambda: converted into new-style theory and document;
  3669 
  3670 * HOL/ex/Multiquote: example of multiple nested quotations and
  3671 anti-quotations -- basically a generalized version of de-Bruijn
  3672 representation; very useful in avoiding lifting of operations;
  3673 
  3674 * HOL/record: added general record equality rule to simpset; fixed
  3675 select-update simplification procedure to handle extended records as
  3676 well; admit "r" as field name;
  3677 
  3678 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3679 other numeric types and also as the identity of groups, rings, etc.;
  3680 
  3681 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3682 Types nat and int belong to this axclass;
  3683 
  3684 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3685    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3686    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3687   two terms #m*u and #n*u are replaced by #(m+n)*u
  3688     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3689   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3690     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3691 
  3692 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3693 powerful prover for predicate logic but knows nothing of clasets; see
  3694 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3695 
  3696 * HOL: new version of "case_tac" subsumes both boolean case split and
  3697 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3698 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3699 
  3700 * HOL: simplification no longer dives into case-expressions: only the
  3701 selector expression is simplified, but not the remaining arms; to
  3702 enable full simplification of case-expressions for datatype t, you may
  3703 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3704 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3705 
  3706 * HOL/recdef: the recursion equations generated by 'recdef' for
  3707 function 'f' are now called f.simps instead of f.rules; if all
  3708 termination conditions are proved automatically, these simplification
  3709 rules are added to the simpset, as in primrec; rules may be named
  3710 individually as well, resulting in a separate list of theorems for
  3711 each equation;
  3712 
  3713 * HOL/While is a new theory that provides a while-combinator. It
  3714 permits the definition of tail-recursive functions without the
  3715 provision of a termination measure. The latter is necessary once the
  3716 invariant proof rule for while is applied.
  3717 
  3718 * HOL: new (overloaded) notation for the set of elements below/above
  3719 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3720 
  3721 * HOL: theorems impI, allI, ballI bound as "strip";
  3722 
  3723 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3724 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3725 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3726 
  3727 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3728 
  3729 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3730 main HOL, but was unused);
  3731 
  3732 * HOL: fewer consts declared as global (e.g. have to refer to
  3733 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3734 
  3735 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3736 in case of overlap with user translations (e.g. judgements over
  3737 tuples); (note that the underlying logical represenation is still
  3738 bogus);
  3739 
  3740 
  3741 *** ZF ***
  3742 
  3743 * ZF: simplification automatically cancels common terms in arithmetic
  3744 expressions over nat and int;
  3745 
  3746 * ZF: new treatment of nat to minimize type-checking: all operators
  3747 coerce their operands to a natural number using the function natify,
  3748 making the algebraic laws unconditional;
  3749 
  3750 * ZF: as above, for int: operators coerce their operands to an integer
  3751 using the function intify;
  3752 
  3753 * ZF: the integer library now contains many of the usual laws for the
  3754 orderings, including $<=, and monotonicity laws for $+ and $*;
  3755 
  3756 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3757 simplification;
  3758 
  3759 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3760 to the simplifier and classical reasoner simultaneously;
  3761 
  3762 
  3763 *** General ***
  3764 
  3765 * Provers: blast_tac now handles actual object-logic rules as
  3766 assumptions; note that auto_tac uses blast_tac internally as well;
  3767 
  3768 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3769 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3770 
  3771 * Provers: delrules now handles destruct rules as well (no longer need
  3772 explicit make_elim);
  3773 
  3774 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3775   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3776 use instead the strong form,
  3777   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3778 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3779 from destruct-rules;
  3780 
  3781 * Provers: Simplifier.easy_setup provides a fast path to basic
  3782 Simplifier setup for new object-logics;
  3783 
  3784 * Pure: AST translation rules no longer require constant head on LHS;
  3785 
  3786 * Pure: improved name spaces: ambiguous output is qualified; support
  3787 for hiding of names;
  3788 
  3789 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3790 XSYMBOL_HOME; no longer need to do manual configuration in most
  3791 situations;
  3792 
  3793 * system: compression of ML heaps images may now be controlled via -c
  3794 option of isabelle and isatool usedir (currently only observed by
  3795 Poly/ML);
  3796 
  3797 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3798 useful for remote X11);
  3799 
  3800 * system: provide TAGS file for Isabelle sources;
  3801 
  3802 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3803 order;
  3804 
  3805 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3806 timing flag supersedes proof_timing and Toplevel.trace;
  3807 
  3808 * ML: new combinators |>> and |>>> for incremental transformations
  3809 with secondary results (e.g. certain theory extensions):
  3810 
  3811 * ML: PureThy.add_defs gets additional argument to indicate potential
  3812 overloading (usually false);
  3813 
  3814 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3815 results;
  3816 
  3817 
  3818 
  3819 New in Isabelle99 (October 1999)
  3820 --------------------------------
  3821 
  3822 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3823 
  3824 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3825 are no longer simplified.  (This allows the simplifier to unfold recursive
  3826 functional programs.)  To restore the old behaviour, declare
  3827 
  3828     Delcongs [if_weak_cong];
  3829 
  3830 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3831 complement;
  3832 
  3833 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3834 
  3835 * HOL/datatype: mutual_induct_tac no longer exists --
  3836   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3837 
  3838 * HOL/typedef: fixed type inference for representing set; type
  3839 arguments now have to occur explicitly on the rhs as type constraints;
  3840 
  3841 * ZF: The con_defs part of an inductive definition may no longer refer
  3842 to constants declared in the same theory;
  3843 
  3844 * HOL, ZF: the function mk_cases, generated by the inductive
  3845 definition package, has lost an argument.  To simplify its result, it
  3846 uses the default simpset instead of a supplied list of theorems.
  3847 
  3848 * HOL/List: the constructors of type list are now Nil and Cons;
  3849 
  3850 * Simplifier: the type of the infix ML functions
  3851         setSSolver addSSolver setSolver addSolver
  3852 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3853 for packaging solvers. A solver is created via
  3854         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3855 where the string argument is only a comment.
  3856 
  3857 
  3858 *** Proof tools ***
  3859 
  3860 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3861 decision procedure for linear arithmetic. Currently it is used for
  3862 types `nat', `int', and `real' in HOL (see below); it can, should and
  3863 will be instantiated for other types and logics as well.
  3864 
  3865 * The simplifier now accepts rewrite rules with flexible heads, eg
  3866      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3867   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3868   matching.
  3869 
  3870 
  3871 *** General ***
  3872 
  3873 * New Isabelle/Isar subsystem provides an alternative to traditional
  3874 tactical theorem proving; together with the ProofGeneral/isar user
  3875 interface it offers an interactive environment for developing human
  3876 readable proof documents (Isar == Intelligible semi-automated
  3877 reasoning); for further information see isatool doc isar-ref,
  3878 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3879 
  3880 * improved and simplified presentation of theories: better HTML markup
  3881 (including colors), graph views in several sizes; isatool usedir now
  3882 provides a proper interface for user theories (via -P option); actual
  3883 document preparation based on (PDF)LaTeX is available as well (for
  3884 new-style theories only); see isatool doc system for more information;
  3885 
  3886 * native support for Proof General, both for classic Isabelle and
  3887 Isabelle/Isar;
  3888 
  3889 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3890 using the graph browser tool;
  3891 
  3892 * Isabelle manuals now also available as PDF;
  3893 
  3894 * theory loader rewritten from scratch (may not be fully
  3895 bug-compatible); old loadpath variable has been replaced by show_path,
  3896 add_path, del_path, reset_path functions; new operations such as
  3897 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3898 isatool doc ref);
  3899 
  3900 * improved isatool install: option -k creates KDE application icon,
  3901 option -p DIR installs standalone binaries;
  3902 
  3903 * added ML_PLATFORM setting (useful for cross-platform installations);
  3904 more robust handling of platform specific ML images for SML/NJ;
  3905 
  3906 * the settings environment is now statically scoped, i.e. it is never
  3907 created again in sub-processes invoked from isabelle, isatool, or
  3908 Isabelle;
  3909 
  3910 * path element specification '~~' refers to '$ISABELLE_HOME';
  3911 
  3912 * in locales, the "assumes" and "defines" parts may be omitted if
  3913 empty;
  3914 
  3915 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3916 long arrows);
  3917 
  3918 * new print_mode "HTML";
  3919 
  3920 * new flag show_tags controls display of tags of theorems (which are
  3921 basically just comments that may be attached by some tools);
  3922 
  3923 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3924 mode and goal output format:
  3925 
  3926 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3927 244c244
  3928 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3929 ---
  3930 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3931 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3932 181c181
  3933 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3934 ---
  3935 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3936 
  3937 * function bind_thms stores lists of theorems (cf. bind_thm);
  3938 
  3939 * new shorthand tactics ftac, eatac, datac, fatac;
  3940 
  3941 * qed (and friends) now accept "" as result name; in that case the
  3942 theorem is not stored, but proper checks and presentation of the
  3943 result still apply;
  3944 
  3945 * theorem database now also indexes constants "Trueprop", "all",
  3946 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3947 
  3948 
  3949 *** HOL ***
  3950 
  3951 ** HOL arithmetic **
  3952 
  3953 * There are now decision procedures for linear arithmetic over nat and
  3954 int:
  3955 
  3956 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3957 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3958 are treated as atomic; subformulae not involving type `nat' or `int'
  3959 are ignored; quantified subformulae are ignored unless they are
  3960 positive universal or negative existential. The tactic has to be
  3961 invoked by hand and can be a little bit slow. In particular, the
  3962 running time is exponential in the number of occurrences of `min' and
  3963 `max', and `-' on `nat'.
  3964 
  3965 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3966 (negated) (in)equalities among the premises and the conclusion into
  3967 account (i.e. no compound formulae) and does not know about `min' and
  3968 `max', and `-' on `nat'. It is fast and is used automatically by the
  3969 simplifier.
  3970 
  3971 NB: At the moment, these decision procedures do not cope with mixed
  3972 nat/int formulae where the two parts interact, such as `m < n ==>
  3973 int(m) < int(n)'.
  3974 
  3975 * HOL/Numeral provides a generic theory of numerals (encoded
  3976 efficiently as bit strings); setup for types nat/int/real is in place;
  3977 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3978 int, existing theories and proof scripts may require a few additional
  3979 type constraints;
  3980 
  3981 * integer division and remainder can now be performed on constant
  3982 arguments;
  3983 
  3984 * many properties of integer multiplication, division and remainder
  3985 are now available;
  3986 
  3987 * An interface to the Stanford Validity Checker (SVC) is available through the
  3988 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3989 are proved automatically.  SVC must be installed separately, and its results
  3990 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3991 invocation of the underlying oracle).  For SVC see
  3992   http://verify.stanford.edu/SVC
  3993 
  3994 * IsaMakefile: the HOL-Real target now builds an actual image;
  3995 
  3996 
  3997 ** HOL misc **
  3998 
  3999 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4000 (in Isabelle/Isar) -- by Gertrud Bauer;
  4001 
  4002 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4003 analysis for assembly languages with subtypes;
  4004 
  4005 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4006 -- avoids syntactic ambiguities and treats state, transition, and
  4007 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4008 changed syntax and (many) tactics;
  4009 
  4010 * HOL/inductive: Now also handles more general introduction rules such
  4011   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4012   theorems are now maintained within the theory (maintained via the
  4013   "mono" attribute);
  4014 
  4015 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4016   (using function types) such as
  4017 
  4018   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4019 
  4020 * HOL/record: record_simproc (part of the default simpset) takes care
  4021 of selectors applied to updated records; record_split_tac is no longer
  4022 part of the default claset; update_defs may now be removed from the
  4023 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4024 
  4025   claset_ref () := claset() addSWrapper record_split_wrapper;
  4026   Delsimprocs [record_simproc]
  4027 
  4028 * HOL/typedef: fixed type inference for representing set; type
  4029 arguments now have to occur explicitly on the rhs as type constraints;
  4030 
  4031 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4032 names rather than an ML expression;
  4033 
  4034 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4035 supplied later.  Program schemes can be defined, such as
  4036     "While B C s = (if B s then While B C (C s) else s)"
  4037 where the well-founded relation can be chosen after B and C have been given.
  4038 
  4039 * HOL/List: the constructors of type list are now Nil and Cons;
  4040 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4041 course, ML tools referring to List.list.op # etc. have to be adapted;
  4042 
  4043 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4044 disabled by default; run isabelle with option -m HOL to get back to
  4045 the original Gordon/HOL-style output;
  4046 
  4047 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4048 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4049 
  4050 * HOL basic syntax simplified (more orthogonal): all variants of
  4051 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4052 Eps operator is provided as well: "SOME x. P[x]";
  4053 
  4054 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4055 
  4056 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4057 thus available for user theories;
  4058 
  4059 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4060 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4061 time;
  4062 
  4063 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4064 several times and then mp;
  4065 
  4066 
  4067 *** LK ***
  4068 
  4069 * the notation <<...>> is now available as a notation for sequences of
  4070 formulas;
  4071 
  4072 * the simplifier is now installed
  4073 
  4074 * the axiom system has been generalized (thanks to Soren Heilmann)
  4075 
  4076 * the classical reasoner now has a default rule database
  4077 
  4078 
  4079 *** ZF ***
  4080 
  4081 * new primrec section allows primitive recursive functions to be given
  4082 directly (as in HOL) over datatypes and the natural numbers;
  4083 
  4084 * new tactics induct_tac and exhaust_tac for induction (or case
  4085 analysis) over datatypes and the natural numbers;
  4086 
  4087 * the datatype declaration of type T now defines the recursor T_rec;
  4088 
  4089 * simplification automatically does freeness reasoning for datatype
  4090 constructors;
  4091 
  4092 * automatic type-inference, with AddTCs command to insert new
  4093 type-checking rules;
  4094 
  4095 * datatype introduction rules are now added as Safe Introduction rules
  4096 to the claset;
  4097 
  4098 * the syntax "if P then x else y" is now available in addition to
  4099 if(P,x,y);
  4100 
  4101 
  4102 *** Internal programming interfaces ***
  4103 
  4104 * tuned simplifier trace output; new flag debug_simp;
  4105 
  4106 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4107 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4108 
  4109 * AxClass.axclass_tac lost the theory argument;
  4110 
  4111 * tuned current_goals_markers semantics: begin / end goal avoids
  4112 printing empty lines;
  4113 
  4114 * removed prs and prs_fn hook, which was broken because it did not
  4115 include \n in its semantics, forcing writeln to add one
  4116 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4117 string -> unit if you really want to output text without newline;
  4118 
  4119 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4120 plain output, interface builders may have to enable 'isabelle_font'
  4121 mode to get Isabelle font glyphs as before;
  4122 
  4123 * refined token_translation interface; INCOMPATIBILITY: output length
  4124 now of type real instead of int;
  4125 
  4126 * theory loader actions may be traced via new ThyInfo.add_hook
  4127 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4128 your own database of information attached to *whole* theories -- as
  4129 opposed to intra-theory data slots offered via TheoryDataFun;
  4130 
  4131 * proper handling of dangling sort hypotheses (at last!);
  4132 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4133 extra sort hypotheses that can be witnessed from the type signature;
  4134 the force_strip_shyps flag is gone, any remaining shyps are simply
  4135 left in the theorem (with a warning issued by strip_shyps_warning);
  4136 
  4137 
  4138 
  4139 New in Isabelle98-1 (October 1998)
  4140 ----------------------------------
  4141 
  4142 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4143 
  4144 * several changes of automated proof tools;
  4145 
  4146 * HOL: major changes to the inductive and datatype packages, including
  4147 some minor incompatibilities of theory syntax;
  4148 
  4149 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4150 called `inj_on';
  4151 
  4152 * HOL: removed duplicate thms in Arith:
  4153   less_imp_add_less  should be replaced by  trans_less_add1
  4154   le_imp_add_le      should be replaced by  trans_le_add1
  4155 
  4156 * HOL: unary minus is now overloaded (new type constraints may be
  4157 required);
  4158 
  4159 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4160 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4161 now taken as an integer constant.
  4162 
  4163 * Pure: ML function 'theory_of' renamed to 'theory';
  4164 
  4165 
  4166 *** Proof tools ***
  4167 
  4168 * Simplifier:
  4169   1. Asm_full_simp_tac is now more aggressive.
  4170      1. It will sometimes reorient premises if that increases their power to
  4171         simplify.
  4172      2. It does no longer proceed strictly from left to right but may also
  4173         rotate premises to achieve further simplification.
  4174      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4175      old Asm_full_simp_tac in that it does not rotate premises.
  4176   2. The simplifier now knows a little bit about nat-arithmetic.
  4177 
  4178 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4179 allows for selected deletion of wrappers, by introduction of names for
  4180 wrapper functionals.  This implies that addbefore, addSbefore,
  4181 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4182 and that adding two tactics with the same name overwrites the first
  4183 one (emitting a warning).
  4184   type wrapper = (int -> tactic) -> (int -> tactic)
  4185   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4186   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4187   delWrapper, delSWrapper: claset *  string            -> claset
  4188   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4189 
  4190 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4191 semantics; addbefore now affects only the unsafe part of step_tac
  4192 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4193 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4194 by Force_tac;
  4195 
  4196 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4197 compWrapper; added safe wrapper (and access functions for it);
  4198 
  4199 * HOL/split_all_tac is now much faster and fails if there is nothing
  4200 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4201 and the names of the automatically generated variables have changed.
  4202 split_all_tac has moved within claset() from unsafe wrappers to safe
  4203 wrappers, which means that !!-bound variables are split much more
  4204 aggressively, and safe_tac and clarify_tac now split such variables.
  4205 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4206 Note: the same holds for record_split_tac, which does the job of
  4207 split_all_tac for record fields.
  4208 
  4209 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4210 permanently to the default simpset using Addsplits just like
  4211 Addsimps. They can be removed via Delsplits just like
  4212 Delsimps. Lower-case versions are also available.
  4213 
  4214 * HOL/Simplifier: The rule split_if is now part of the default
  4215 simpset. This means that the simplifier will eliminate all occurrences
  4216 of if-then-else in the conclusion of a goal. To prevent this, you can
  4217 either remove split_if completely from the default simpset by
  4218 `Delsplits [split_if]' or remove it in a specific call of the
  4219 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4220 other case splitting rules to/from the default simpset: every datatype
  4221 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4222 t is the name of the datatype).
  4223 
  4224 * Classical reasoner / Simplifier combination: new force_tac (and
  4225 derivatives Force_tac, force) combines rewriting and classical
  4226 reasoning (and whatever other tools) similarly to auto_tac, but is
  4227 aimed to solve the given subgoal completely.
  4228 
  4229 
  4230 *** General ***
  4231 
  4232 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4233 and `goalw': the theory is no longer needed as an explicit argument -
  4234 the current theory context is used; assumptions are no longer returned
  4235 at the ML-level unless one of them starts with ==> or !!; it is
  4236 recommended to convert to these new commands using isatool fixgoal
  4237 (backup your sources first!);
  4238 
  4239 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4240 the current theory context, and 'theory' to lookup stored theories;
  4241 
  4242 * new theory section 'locale' for declaring constants, assumptions and
  4243 definitions that have local scope;
  4244 
  4245 * new theory section 'nonterminals' for purely syntactic types;
  4246 
  4247 * new theory section 'setup' for generic ML setup functions
  4248 (e.g. package initialization);
  4249 
  4250 * the distribution now includes Isabelle icons: see
  4251 lib/logo/isabelle-{small,tiny}.xpm;
  4252 
  4253 * isatool install - install binaries with absolute references to
  4254 ISABELLE_HOME/bin;
  4255 
  4256 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4257 
  4258 * print mode 'emacs' reserved for Isamode;
  4259 
  4260 * support multiple print (ast) translations per constant name;
  4261 
  4262 * theorems involving oracles are now printed with a suffixed [!];
  4263 
  4264 
  4265 *** HOL ***
  4266 
  4267 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4268 
  4269 * HOL/inductive package reorganized and improved: now supports mutual
  4270 definitions such as
  4271 
  4272   inductive EVEN ODD
  4273     intrs
  4274       null "0 : EVEN"
  4275       oddI "n : EVEN ==> Suc n : ODD"
  4276       evenI "n : ODD ==> Suc n : EVEN"
  4277 
  4278 new theorem list "elims" contains an elimination rule for each of the
  4279 recursive sets; inductive definitions now handle disjunctive premises
  4280 correctly (also ZF);
  4281 
  4282 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4283 "mutual_induct" no longer exists - the induction rule is always
  4284 contained in "induct";
  4285 
  4286 
  4287 * HOL/datatype package re-implemented and greatly improved: now
  4288 supports mutually recursive datatypes such as
  4289 
  4290   datatype
  4291     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4292             | SUM ('a aexp) ('a aexp)
  4293             | DIFF ('a aexp) ('a aexp)
  4294             | NUM 'a
  4295   and
  4296     'a bexp = LESS ('a aexp) ('a aexp)
  4297             | AND ('a bexp) ('a bexp)
  4298             | OR ('a bexp) ('a bexp)
  4299 
  4300 as well as indirectly recursive datatypes such as
  4301 
  4302   datatype
  4303     ('a, 'b) term = Var 'a
  4304                   | App 'b ((('a, 'b) term) list)
  4305 
  4306 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4307 induction on mutually / indirectly recursive datatypes.
  4308 
  4309 Primrec equations are now stored in theory and can be accessed via
  4310 <function_name>.simps.
  4311 
  4312 INCOMPATIBILITIES:
  4313 
  4314   - Theories using datatypes must now have theory Datatype as an
  4315     ancestor.
  4316   - The specific <typename>.induct_tac no longer exists - use the
  4317     generic induct_tac instead.
  4318   - natE has been renamed to nat.exhaust - use exhaust_tac
  4319     instead of res_inst_tac ... natE. Note that the variable
  4320     names in nat.exhaust differ from the names in natE, this
  4321     may cause some "fragile" proofs to fail.
  4322   - The theorems split_<typename>_case and split_<typename>_case_asm
  4323     have been renamed to <typename>.split and <typename>.split_asm.
  4324   - Since default sorts of type variables are now handled correctly,
  4325     some datatype definitions may have to be annotated with explicit
  4326     sort constraints.
  4327   - Primrec definitions no longer require function name and type
  4328     of recursive argument.
  4329 
  4330 Consider using isatool fixdatatype to adapt your theories and proof
  4331 scripts to the new package (backup your sources first!).
  4332 
  4333 
  4334 * HOL/record package: considerably improved implementation; now
  4335 includes concrete syntax for record types, terms, updates; theorems
  4336 for surjective pairing and splitting !!-bound record variables; proof
  4337 support is as follows:
  4338 
  4339   1) standard conversions (selectors or updates applied to record
  4340 constructor terms) are part of the standard simpset;
  4341 
  4342   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4343 made part of standard simpset and claset via addIffs;
  4344 
  4345   3) a tactic for record field splitting (record_split_tac) is part of
  4346 the standard claset (addSWrapper);
  4347 
  4348 To get a better idea about these rules you may retrieve them via
  4349 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4350 the name of your record type.
  4351 
  4352 The split tactic 3) conceptually simplifies by the following rule:
  4353 
  4354   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4355 
  4356 Thus any record variable that is bound by meta-all will automatically
  4357 blow up into some record constructor term, consequently the
  4358 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4359 solve record problems automatically.
  4360 
  4361 
  4362 * reorganized the main HOL image: HOL/Integ and String loaded by
  4363 default; theory Main includes everything;
  4364 
  4365 * automatic simplification of integer sums and comparisons, using cancellation;
  4366 
  4367 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4368 
  4369 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4370 
  4371 * many new identities for unions, intersections, set difference, etc.;
  4372 
  4373 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4374 called split_if, split_split, split_sum_case and split_nat_case (to go
  4375 with add/delsplits);
  4376 
  4377 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4378 (?x::unit) = (); this is made part of the default simpset, which COULD
  4379 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4380 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4381 unit_abs_eta_conv is added in order to counter the effect of
  4382 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4383 %u.f();
  4384 
  4385 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4386 makes more sense);
  4387 
  4388 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4389   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4390   disjointness reasoning but breaking a few old proofs.
  4391 
  4392 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4393 to 'converse' from 'inverse' (for compatibility with ZF and some
  4394 literature);
  4395 
  4396 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4397 the well-founded relation;
  4398 
  4399 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4400     Compl A.  The "Compl" syntax remains available as input syntax for this
  4401     release ONLY.
  4402 
  4403 * HOL/Update: new theory of function updates:
  4404     f(a:=b) == %x. if x=a then b else f x
  4405 may also be iterated as in f(a:=b,c:=d,...);
  4406 
  4407 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4408 
  4409 * HOL/List:
  4410   - new function list_update written xs[i:=v] that updates the i-th
  4411     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4412   - new function `upt' written [i..j(] which generates the list
  4413     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4414     bound write [i..j], which is a shorthand for [i..j+1(].
  4415   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4416 
  4417 * HOL/Arith:
  4418   - removed 'pred' (predecessor) function;
  4419   - generalized some theorems about n-1;
  4420   - many new laws about "div" and "mod";
  4421   - new laws about greatest common divisors (see theory ex/Primes);
  4422 
  4423 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4424 instead of "inverse";
  4425 
  4426 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4427   of the multiset ordering;
  4428 
  4429 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4430   (not included by default);
  4431 
  4432 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4433 
  4434 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4435   programs, i.e. different program variables may have different types.
  4436 
  4437 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4438   [previously, this check worked only if the rewrite rule was unconditional]
  4439   Now rew can involve either definitions or equalities (either == or =).
  4440 
  4441 
  4442 *** ZF ***
  4443 
  4444 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4445   only the theorems proved on ZF.ML;
  4446 
  4447 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4448   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4449   disjointness reasoning but breaking a few old proofs.
  4450 
  4451 * ZF/Update: new theory of function updates
  4452     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4453   may also be iterated as in f(a:=b,c:=d,...);
  4454 
  4455 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4456 
  4457 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4458   [previously, this check worked only if the rewrite rule was unconditional]
  4459   Now rew can involve either definitions or equalities (either == or =).
  4460 
  4461 * case_tac provided for compatibility with HOL
  4462     (like the old excluded_middle_tac, but with subgoals swapped)
  4463 
  4464 
  4465 *** Internal programming interfaces ***
  4466 
  4467 * Pure: several new basic modules made available for general use, see
  4468 also src/Pure/README;
  4469 
  4470 * improved the theory data mechanism to support encapsulation (data
  4471 kind name replaced by private Object.kind, acting as authorization
  4472 key); new type-safe user interface via functor TheoryDataFun; generic
  4473 print_data function becomes basically useless;
  4474 
  4475 * removed global_names compatibility flag -- all theory declarations
  4476 are qualified by default;
  4477 
  4478 * module Pure/Syntax now offers quote / antiquote translation
  4479 functions (useful for Hoare logic etc. with implicit dependencies);
  4480 see HOL/ex/Antiquote for an example use;
  4481 
  4482 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4483 cterm -> thm;
  4484 
  4485 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4486 subgoal;
  4487 
  4488 * Display.print_goals function moved to Locale.print_goals;
  4489 
  4490 * standard print function for goals supports current_goals_markers
  4491 variable for marking begin of proof, end of proof, start of goal; the
  4492 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4493 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4494 for example;
  4495 
  4496 
  4497 
  4498 New in Isabelle98 (January 1998)
  4499 --------------------------------
  4500 
  4501 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4502 
  4503 * changed lexical syntax of terms / types: dots made part of long
  4504 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4505 
  4506 * simpset (and claset) reference variable replaced by functions
  4507 simpset / simpset_ref;
  4508 
  4509 * no longer supports theory aliases (via merge) and non-trivial
  4510 implicit merge of thms' signatures;
  4511 
  4512 * most internal names of constants changed due to qualified names;
  4513 
  4514 * changed Pure/Sequence interface (see Pure/seq.ML);
  4515 
  4516 
  4517 *** General Changes ***
  4518 
  4519 * hierachically structured name spaces (for consts, types, axms, thms
  4520 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4521 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4522 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4523 long_names for fully qualified output names; NOTE: ML programs
  4524 (special tactics, packages etc.) referring to internal names may have
  4525 to be adapted to cope with fully qualified names; in case of severe
  4526 backward campatibility problems try setting 'global_names' at compile
  4527 time to have enrything declared within a flat name space; one may also
  4528 fine tune name declarations in theories via the 'global' and 'local'
  4529 section;
  4530 
  4531 * reimplemented the implicit simpset and claset using the new anytype
  4532 data filed in signatures; references simpset:simpset ref etc. are
  4533 replaced by functions simpset:unit->simpset and
  4534 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4535 to patch your ML files accordingly;
  4536 
  4537 * HTML output now includes theory graph data for display with Java
  4538 applet or isatool browser; data generated automatically via isatool
  4539 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4540 
  4541 * defs may now be conditional; improved rewrite_goals_tac to handle
  4542 conditional equations;
  4543 
  4544 * defs now admits additional type arguments, using TYPE('a) syntax;
  4545 
  4546 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4547 creates a new theory node; implicit merge of thms' signatures is
  4548 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4549 transfer:theory->thm->thm in (rare) cases;
  4550 
  4551 * improved handling of draft signatures / theories; draft thms (and
  4552 ctyps, cterms) are automatically promoted to real ones;
  4553 
  4554 * slightly changed interfaces for oracles: admit many per theory, named
  4555 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4556 
  4557 * print_goals: optional output of const types (set show_consts and
  4558 show_types);
  4559 
  4560 * improved output of warnings (###) and errors (***);
  4561 
  4562 * subgoal_tac displays a warning if the new subgoal has type variables;
  4563 
  4564 * removed old README and Makefiles;
  4565 
  4566 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4567 
  4568 * removed obsolete init_pps and init_database;
  4569 
  4570 * deleted the obsolete tactical STATE, which was declared by
  4571     fun STATE tacfun st = tacfun st st;
  4572 
  4573 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4574 (which abbreviates $HOME);
  4575 
  4576 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4577 use isatool fixseq to adapt your ML programs (this works for fully
  4578 qualified references to the Sequence structure only!);
  4579 
  4580 * use_thy no longer requires writable current directory; it always
  4581 reloads .ML *and* .thy file, if either one is out of date;
  4582 
  4583 
  4584 *** Classical Reasoner ***
  4585 
  4586 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4587 tactics that use classical reasoning to simplify a subgoal without
  4588 splitting it into several subgoals;
  4589 
  4590 * Safe_tac: like safe_tac but uses the default claset;
  4591 
  4592 
  4593 *** Simplifier ***
  4594 
  4595 * added simplification meta rules:
  4596     (asm_)(full_)simplify: simpset -> thm -> thm;
  4597 
  4598 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4599 logics (again);
  4600 
  4601 * added prems argument to simplification procedures;
  4602 
  4603 * HOL, FOL, ZF: added infix function `addsplits':
  4604   instead of `<simpset> setloop (split_tac <thms>)'
  4605   you can simply write `<simpset> addsplits <thms>'
  4606 
  4607 
  4608 *** Syntax ***
  4609 
  4610 * TYPE('a) syntax for type reflection terms;
  4611 
  4612 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4613 
  4614 * pretty printer: changed order of mixfix annotation preference (again!);
  4615 
  4616 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4617 
  4618 
  4619 *** HOL ***
  4620 
  4621 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4622   with `addloop' of the simplifier to faciliate case splitting in premises.
  4623 
  4624 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4625 
  4626 * HOL/Auth: new protocol proofs including some for the Internet
  4627   protocol TLS;
  4628 
  4629 * HOL/Map: new theory of `maps' a la VDM;
  4630 
  4631 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4632 cancelling out common nat summands from =, <, <= (in)equalities, or
  4633 differences; simplification procedures nat_cancel_factor for
  4634 cancelling common factor from =, <, <= (in)equalities over natural
  4635 sums; nat_cancel contains both kinds of procedures, it is installed by
  4636 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4637 
  4638 * HOL/simplifier: terms of the form
  4639   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4640   are rewritten to
  4641   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4642   and those of the form
  4643   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4644   are rewritten to
  4645   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4646 
  4647 * HOL/datatype
  4648   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4649 
  4650   P(t_case f1 ... fn x) =
  4651      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4652         ...
  4653        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4654      )
  4655 
  4656   and a theorem `split_t_case_asm' of the form
  4657 
  4658   P(t_case f1 ... fn x) =
  4659     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4660         ...
  4661        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4662      )
  4663   which can be added to a simpset via `addsplits'. The existing theorems
  4664   expand_list_case and expand_option_case have been renamed to
  4665   split_list_case and split_option_case.
  4666 
  4667 * HOL/Arithmetic:
  4668   - `pred n' is automatically converted to `n-1'.
  4669     Users are strongly encouraged not to use `pred' any longer,
  4670     because it will disappear altogether at some point.
  4671   - Users are strongly encouraged to write "0 < n" rather than
  4672     "n ~= 0". Theorems and proof tools have been modified towards this
  4673     `standard'.
  4674 
  4675 * HOL/Lists:
  4676   the function "set_of_list" has been renamed "set" (and its theorems too);
  4677   the function "nth" now takes its arguments in the reverse order and
  4678   has acquired the infix notation "!" as in "xs!n".
  4679 
  4680 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4681 
  4682 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4683   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4684 
  4685 * HOL/record: extensible records with schematic structural subtyping
  4686 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4687 still lacks various theorems and concrete record syntax;
  4688 
  4689 
  4690 *** HOLCF ***
  4691 
  4692 * removed "axioms" and "generated by" sections;
  4693 
  4694 * replaced "ops" section by extended "consts" section, which is capable of
  4695   handling the continuous function space "->" directly;
  4696 
  4697 * domain package:
  4698   . proves theorems immediately and stores them in the theory,
  4699   . creates hierachical name space,
  4700   . now uses normal mixfix annotations (instead of cinfix...),
  4701   . minor changes to some names and values (for consistency),
  4702   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4703   . separator between mutual domain defs: changed "," to "and",
  4704   . improved handling of sort constraints;  now they have to
  4705     appear on the left-hand side of the equations only;
  4706 
  4707 * fixed LAM <x,y,zs>.b syntax;
  4708 
  4709 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4710 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4711 
  4712 
  4713 *** FOL and ZF ***
  4714 
  4715 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4716   with `addloop' of the simplifier to faciliate case splitting in premises.
  4717 
  4718 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4719 in HOL, they strip ALL and --> from proved theorems;
  4720 
  4721 
  4722 
  4723 New in Isabelle94-8 (May 1997)
  4724 ------------------------------
  4725 
  4726 *** General Changes ***
  4727 
  4728 * new utilities to build / run / maintain Isabelle etc. (in parts
  4729 still somewhat experimental); old Makefiles etc. still functional;
  4730 
  4731 * new 'Isabelle System Manual';
  4732 
  4733 * INSTALL text, together with ./configure and ./build scripts;
  4734 
  4735 * reimplemented type inference for greater efficiency, better error
  4736 messages and clean internal interface;
  4737 
  4738 * prlim command for dealing with lots of subgoals (an easier way of
  4739 setting goals_limit);
  4740 
  4741 
  4742 *** Syntax ***
  4743 
  4744 * supports alternative (named) syntax tables (parser and pretty
  4745 printer); internal interface is provided by add_modesyntax(_i);
  4746 
  4747 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4748 be used in conjunction with the Isabelle symbol font; uses the
  4749 "symbols" syntax table;
  4750 
  4751 * added token_translation interface (may translate name tokens in
  4752 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4753 the current print_mode); IMPORTANT: user print translation functions
  4754 are responsible for marking newly introduced bounds
  4755 (Syntax.mark_boundT);
  4756 
  4757 * token translations for modes "xterm" and "xterm_color" that display
  4758 names in bold, underline etc. or colors (which requires a color
  4759 version of xterm);
  4760 
  4761 * infixes may now be declared with names independent of their syntax;
  4762 
  4763 * added typed_print_translation (like print_translation, but may
  4764 access type of constant);
  4765 
  4766 
  4767 *** Classical Reasoner ***
  4768 
  4769 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4770 some limitations.  Blast_tac...
  4771   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4772   + ignores elimination rules that don't have the correct format
  4773         (the conclusion MUST be a formula variable)
  4774   + ignores types, which can make HOL proofs fail
  4775   + rules must not require higher-order unification, e.g. apply_type in ZF
  4776     [message "Function Var's argument not a bound variable" relates to this]
  4777   + its proof strategy is more general but can actually be slower
  4778 
  4779 * substitution with equality assumptions no longer permutes other
  4780 assumptions;
  4781 
  4782 * minor changes in semantics of addafter (now called addaltern); renamed
  4783 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4784 (and access functions for it);
  4785 
  4786 * improved combination of classical reasoner and simplifier:
  4787   + functions for handling clasimpsets
  4788   + improvement of addss: now the simplifier is called _after_ the
  4789     safe steps.
  4790   + safe variant of addss called addSss: uses safe simplifications
  4791     _during_ the safe steps. It is more complete as it allows multiple
  4792     instantiations of unknowns (e.g. with slow_tac).
  4793 
  4794 *** Simplifier ***
  4795 
  4796 * added interface for simplification procedures (functions that
  4797 produce *proven* rewrite rules on the fly, depending on current
  4798 redex);
  4799 
  4800 * ordering on terms as parameter (used for ordered rewriting);
  4801 
  4802 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4803 
  4804 * the solver is now split into a safe and an unsafe part.
  4805 This should be invisible for the normal user, except that the
  4806 functions setsolver and addsolver have been renamed to setSolver and
  4807 addSolver; added safe_asm_full_simp_tac;
  4808 
  4809 
  4810 *** HOL ***
  4811 
  4812 * a generic induction tactic `induct_tac' which works for all datatypes and
  4813 also for type `nat';
  4814 
  4815 * a generic case distinction tactic `exhaust_tac' which works for all
  4816 datatypes and also for type `nat';
  4817 
  4818 * each datatype comes with a function `size';
  4819 
  4820 * patterns in case expressions allow tuple patterns as arguments to
  4821 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4822 
  4823 * primrec now also works with type nat;
  4824 
  4825 * recdef: a new declaration form, allows general recursive functions to be
  4826 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4827 
  4828 * the constant for negation has been renamed from "not" to "Not" to
  4829 harmonize with FOL, ZF, LK, etc.;
  4830 
  4831 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4832 infinite lists;
  4833 
  4834 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4835 
  4836 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4837 problems in commutative rings, using axiomatic type classes for + and *;
  4838 
  4839 * more examples in HOL/MiniML and HOL/Auth;
  4840 
  4841 * more default rewrite rules for quantifiers, union/intersection;
  4842 
  4843 * a new constant `arbitrary == @x.False';
  4844 
  4845 * HOLCF/IOA replaces old HOL/IOA;
  4846 
  4847 * HOLCF changes: derived all rules and arities
  4848   + axiomatic type classes instead of classes
  4849   + typedef instead of faking type definitions
  4850   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4851   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4852   + eliminated the types void, one, tr
  4853   + use unit lift and bool lift (with translations) instead of one and tr
  4854   + eliminated blift from Lift3.thy (use Def instead of blift)
  4855   all eliminated rules are derived as theorems --> no visible changes ;
  4856 
  4857 
  4858 *** ZF ***
  4859 
  4860 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4861 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4862 as ZF_cs addSIs [equalityI];
  4863 
  4864 
  4865 
  4866 New in Isabelle94-7 (November 96)
  4867 ---------------------------------
  4868 
  4869 * allowing negative levels (as offsets) in prlev and choplev;
  4870 
  4871 * super-linear speedup for large simplifications;
  4872 
  4873 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4874 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4875 FAIL); can suppress it using the command Delsimps (ex_simps @
  4876 all_simps); De Morgan laws are also now included, by default;
  4877 
  4878 * improved printing of ==>  :  ~:
  4879 
  4880 * new object-logic "Sequents" adds linear logic, while replacing LK
  4881 and Modal (thanks to Sara Kalvala);
  4882 
  4883 * HOL/Auth: correctness proofs for authentication protocols;
  4884 
  4885 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4886 examples on HOL/Auth);
  4887 
  4888 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4889 the rewriter and classical reasoner simultaneously;
  4890 
  4891 * function uresult no longer returns theorems in "standard" format;
  4892 regain previous version by: val uresult = standard o uresult;
  4893 
  4894 
  4895 
  4896 New in Isabelle94-6
  4897 -------------------
  4898 
  4899 * oracles -- these establish an interface between Isabelle and trusted
  4900 external reasoners, which may deliver results as theorems;
  4901 
  4902 * proof objects (in particular record all uses of oracles);
  4903 
  4904 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4905 
  4906 * "constdefs" section in theory files;
  4907 
  4908 * "primrec" section (HOL) no longer requires names;
  4909 
  4910 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4911 
  4912 
  4913 
  4914 New in Isabelle94-5
  4915 -------------------
  4916 
  4917 * reduced space requirements;
  4918 
  4919 * automatic HTML generation from theories;
  4920 
  4921 * theory files no longer require "..." (quotes) around most types;
  4922 
  4923 * new examples, including two proofs of the Church-Rosser theorem;
  4924 
  4925 * non-curried (1994) version of HOL is no longer distributed;
  4926 
  4927 
  4928 
  4929 New in Isabelle94-4
  4930 -------------------
  4931 
  4932 * greatly reduced space requirements;
  4933 
  4934 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4935 
  4936 * searchable theorem database (see the section "Retrieving theorems" on
  4937 page 8 of the Reference Manual);
  4938 
  4939 * new examples, including Grabczewski's monumental case study of the
  4940 Axiom of Choice;
  4941 
  4942 * The previous version of HOL renamed to Old_HOL;
  4943 
  4944 * The new version of HOL (previously called CHOL) uses a curried syntax
  4945 for functions.  Application looks like f a b instead of f(a,b);
  4946 
  4947 * Mutually recursive inductive definitions finally work in HOL;
  4948 
  4949 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4950 translates to the operator "split";
  4951 
  4952 
  4953 
  4954 New in Isabelle94-3
  4955 -------------------
  4956 
  4957 * new infix operator, addss, allowing the classical reasoner to
  4958 perform simplification at each step of its search.  Example:
  4959         fast_tac (cs addss ss)
  4960 
  4961 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4962 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4963 look like (a,b) instead of <a,b>;
  4964 
  4965 * PLEASE NOTE: CHOL will eventually replace HOL!
  4966 
  4967 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4968 It translates to the operator "split".  A new theory of integers is available;
  4969 
  4970 * In ZF, integer numerals now denote two's-complement binary integers.
  4971 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4972 
  4973 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4974 of the Axiom of Choice;
  4975 
  4976 
  4977 
  4978 New in Isabelle94-2
  4979 -------------------
  4980 
  4981 * Significantly faster resolution;
  4982 
  4983 * the different sections in a .thy file can now be mixed and repeated
  4984 freely;
  4985 
  4986 * Database of theorems for FOL, HOL and ZF.  New
  4987 commands including qed, qed_goal and bind_thm store theorems in the database.
  4988 
  4989 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4990 a given theory (thms_of), or find out what theory a theorem was proved in
  4991 (theory_of_thm);
  4992 
  4993 * Bugs fixed in the inductive definition and datatype packages;
  4994 
  4995 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4996 and HOL_dup_cs obsolete;
  4997 
  4998 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4999 have been removed;
  5000 
  5001 * Simpler definition of function space in ZF;
  5002 
  5003 * new results about cardinal and ordinal arithmetic in ZF;
  5004 
  5005 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5006 types;
  5007 
  5008 :mode=text:wrap=hard:maxLineLen=72:
  5009 $Id$