NEWS
author wenzelm
Fri Jul 20 19:13:07 2007 +0200 (2007-07-20)
changeset 23889 1794f405eacc
parent 23888 babe337cce2d
child 23920 4288dc7dc248
permissions -rw-r--r--
tuned;
     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.  Potential
    30 INCOMPATIBILITY, may need to refine theory headers.
    31 
    32 * Theory loader: optional support for content-based file
    33 identification, instead of the traditional scheme of full physical
    34 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
    35 (cf. the system manual).  The new scheme allows to work with
    36 non-finished theories in persistent session images, such that source
    37 files may be moved later on without requiring reloads.
    38 
    39 * Legacy goal package: reduced interface to the bare minimum required
    40 to keep existing proof scripts running.  Most other user-level
    41 functions are now part of the OldGoals structure, which is *not* open
    42 by default (consider isatool expandshort before open OldGoals).
    43 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    44 these tend to cause confusion about the actual goal (!) context being
    45 used here, which is not necessarily the same as the_context().
    46 
    47 * Command 'find_theorems': supports "*" wild-card in "name:"
    48 criterion; "with_dups" option.  Certain ProofGeneral versions might
    49 support a specific search form (see ProofGeneral/CHANGES).
    50 
    51 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    52 by default, which means that "prems" (and also "fixed variables") are
    53 suppressed from proof state output.  Note that the ProofGeneral
    54 settings mechanism allows to change and save options persistently, but
    55 older versions of Isabelle will fail to start up if a negative prems
    56 limit is imposed.
    57 
    58 * Local theory targets may be specified by non-nested blocks of
    59 ``context/locale/class ... begin'' followed by ``end''.  The body may
    60 contain definitions, theorems etc., including any derived mechanism
    61 that has been implemented on top of these primitives.  This concept
    62 generalizes the existing ``theorem (in ...)'' towards more versatility
    63 and scalability.
    64 
    65 * Proof General interface: proper undo of final 'end' command;
    66 discontinued Isabelle/classic mode (ML proof scripts).
    67 
    68 
    69 *** Document preparation ***
    70 
    71 * Added antiquotation @{theory name} which prints the given name,
    72 after checking that it refers to a valid ancestor theory in the
    73 current context.
    74 
    75 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    76 check the given source text as ML type/structure, printing verbatim.
    77 
    78 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    79 "c args == rhs" given in the current context.  (Any number of
    80 arguments may be given on the LHS.)
    81 
    82 
    83 
    84 *** Pure ***
    85 
    86 * code generator: consts in 'consts_code' Isar commands are now referred
    87   to by usual term syntax (including optional type annotations).
    88 
    89 * code generator: 
    90   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    91     explicitly to the table of defining equations
    92   - primitive definitions are not used as defining equations by default any longer
    93   - defining equations are now definitly restricted to meta "==" and object
    94         equality "="
    95   - HOL theories have been adopted accordingly
    96 
    97 * class_package.ML offers a combination of axclasses and locales to
    98 achieve Haskell-like type classes in Isabelle.  See
    99 HOL/ex/Classpackage.thy for examples.
   100 
   101 * Yet another code generator framework allows to generate executable
   102 code for ML and Haskell (including "class"es).  A short usage sketch:
   103 
   104     internal compilation:
   105         code_gen <list of constants (term syntax)> in SML
   106     writing SML code to a file:
   107         code_gen <list of constants (term syntax)> in SML <filename>
   108     writing OCaml code to a file:
   109         code_gen <list of constants (term syntax)> in OCaml <filename>
   110     writing Haskell code to a bunch of files:
   111         code_gen <list of constants (term syntax)> in Haskell <filename>
   112 
   113 Reasonable default setup of framework in HOL/Main.
   114 
   115 Theorem attributs for selecting and transforming function equations theorems:
   116 
   117     [code fun]:        select a theorem as function equation for a specific constant
   118     [code fun del]:    deselect a theorem as function equation for a specific constant
   119     [code inline]:     select an equation theorem for unfolding (inlining) in place
   120     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   121 
   122 User-defined serializations (target in {SML, OCaml, Haskell}):
   123 
   124     code_const <and-list of constants (term syntax)>
   125       {(target) <and-list of const target syntax>}+
   126 
   127     code_type <and-list of type constructors>
   128       {(target) <and-list of type target syntax>}+
   129 
   130     code_instance <and-list of instances>
   131       {(target)}+
   132         where instance ::= <type constructor> :: <class>
   133 
   134     code_class <and_list of classes>
   135       {(target) <and-list of class target syntax>}+
   136         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   137 
   138 code_instance and code_class only apply to target Haskell.
   139 
   140 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   141 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   142 
   143 * Command 'no_translations' removes translation rules from theory
   144 syntax.
   145 
   146 * Overloaded definitions are now actually checked for acyclic
   147 dependencies.  The overloading scheme is slightly more general than
   148 that of Haskell98, although Isabelle does not demand an exact
   149 correspondence to type class and instance declarations.
   150 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   151 exotic versions of overloading -- at the discretion of the user!
   152 
   153 Polymorphic constants are represented via type arguments, i.e. the
   154 instantiation that matches an instance against the most general
   155 declaration given in the signature.  For example, with the declaration
   156 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   157 as c(nat).  Overloading is essentially simultaneous structural
   158 recursion over such type arguments.  Incomplete specification patterns
   159 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   160 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   161 Command 'print_theory' outputs the normalized system of recursive
   162 equations, see section "definitions".
   163 
   164 * Isar: method "assumption" (and implicit closing of subproofs) now
   165 takes simple non-atomic goal assumptions into account: after applying
   166 an assumption as a rule the resulting subgoals are solved by atomic
   167 assumption steps.  This is particularly useful to finish 'obtain'
   168 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   169 without referring to the original premise "!!x. P x ==> thesis" in the
   170 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   171 more permissive.
   172 
   173 * Isar: implicit use of prems from the Isar proof context is
   174 considered a legacy feature.  Common applications like ``have A .''
   175 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   176 referencing facts explicitly here improves readability and
   177 maintainability of proof texts.
   178 
   179 * Isar: improper proof element 'guess' is like 'obtain', but derives
   180 the obtained context from the course of reasoning!  For example:
   181 
   182   assume "EX x y. A x & B y"   -- "any previous fact"
   183   then guess x and y by clarify
   184 
   185 This technique is potentially adventurous, depending on the facts and
   186 proof tools being involved here.
   187 
   188 * Isar: known facts from the proof context may be specified as literal
   189 propositions, using ASCII back-quote syntax.  This works wherever
   190 named facts used to be allowed so far, in proof commands, proof
   191 methods, attributes etc.  Literal facts are retrieved from the context
   192 according to unification of type and term parameters.  For example,
   193 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   194 theorems in the current context, then these are valid literal facts:
   195 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   196 
   197 There is also a proof method "fact" which does the same composition
   198 for explicit goal states, e.g. the following proof texts coincide with
   199 certain special cases of literal facts:
   200 
   201   have "A" by fact                 ==  note `A`
   202   have "A ==> B" by fact           ==  note `A ==> B`
   203   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   204   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   205 
   206 * Isar: ":" (colon) is no longer a symbolic identifier character in
   207 outer syntax.  Thus symbolic identifiers may be used without
   208 additional white space in declarations like this: ``assume *: A''.
   209 
   210 * Isar: 'print_facts' prints all local facts of the current context,
   211 both named and unnamed ones.
   212 
   213 * Isar: 'def' now admits simultaneous definitions, e.g.:
   214 
   215   def x == "t" and y == "u"
   216 
   217 * Isar: added command 'unfolding', which is structurally similar to
   218 'using', but affects both the goal state and facts by unfolding given
   219 rewrite rules.  Thus many occurrences of the 'unfold' method or
   220 'unfolded' attribute may be replaced by first-class proof text.
   221 
   222 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   223 and command 'unfolding' now all support object-level equalities
   224 (potentially conditional).  The underlying notion of rewrite rule is
   225 analogous to the 'rule_format' attribute, but *not* that of the
   226 Simplifier (which is usually more generous).
   227 
   228 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   229 method expression within a sandbox consisting of the first N
   230 sub-goals, which need to exist.  For example, ``simp_all [3]''
   231 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   232 simplifies all new goals that emerge from applying rule foo to the
   233 originally first one.
   234 
   235 * Isar: schematic goals are no longer restricted to higher-order
   236 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   237 expected.
   238 
   239 * Isar: the conclusion of a long theorem statement is now either
   240 'shows' (a simultaneous conjunction, as before), or 'obtains'
   241 (essentially a disjunction of cases with local parameters and
   242 assumptions).  The latter allows to express general elimination rules
   243 adequately; in this notation common elimination rules look like this:
   244 
   245   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   246     assumes "EX x. P x"
   247     obtains x where "P x"
   248 
   249   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   250     assumes "A & B"
   251     obtains A and B
   252 
   253   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   254     assumes "A | B"
   255     obtains
   256       A
   257     | B
   258 
   259 The subsequent classical rules even refer to the formal "thesis"
   260 explicitly:
   261 
   262   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   263     obtains "~ thesis"
   264 
   265   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   266     obtains "thesis ==> something"
   267 
   268 The actual proof of an 'obtains' statement is analogous to that of the
   269 Isar proof element 'obtain', only that there may be several cases.
   270 Optional case names may be specified in parentheses; these will be
   271 available both in the present proof and as annotations in the
   272 resulting rule, for later use with the 'cases' method (cf. attribute
   273 case_names).
   274 
   275 * Isar: the assumptions of a long theorem statement are available as
   276 "assms" fact in the proof context.  This is more appropriate than the
   277 (historical) "prems", which refers to all assumptions of the current
   278 context, including those from the target locale, proof body etc.
   279 
   280 * Isar: 'print_statement' prints theorems from the current theory or
   281 proof context in long statement form, according to the syntax of a
   282 top-level lemma.
   283 
   284 * Isar: 'obtain' takes an optional case name for the local context
   285 introduction rule (default "that").
   286 
   287 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   288 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   289 to occur.
   290 
   291 * Pure: syntax "CONST name" produces a fully internalized constant
   292 according to the current context.  This is particularly useful for
   293 syntax translations that should refer to internal constant
   294 representations independently of name spaces.
   295 
   296 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   297 instead of "FOO ". This allows multiple binder declarations to coexist
   298 in the same context.  INCOMPATIBILITY.
   299 
   300 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   301 primitive that also works in a locale context (both for constants and
   302 fixed variables).  Type declaration and internal syntactic
   303 representation of given constants retrieved from the context.
   304 
   305 * Isar/locales: new derived specification elements 'axiomatization',
   306 'definition', 'abbreviation', which support type-inference, admit
   307 object-level specifications (equality, equivalence).  See also the
   308 isar-ref manual.  Examples:
   309 
   310   axiomatization
   311     eq  (infix "===" 50) where
   312     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   313 
   314   definition "f x y = x + y + 1"
   315   definition g where "g x = f x x"
   316 
   317   abbreviation
   318     neq  (infix "=!=" 50) where
   319     "x =!= y == ~ (x === y)"
   320 
   321 These specifications may be also used in a locale context.  Then the
   322 constants being introduced depend on certain fixed parameters, and the
   323 constant name is qualified by the locale base name.  An internal
   324 abbreviation takes care for convenient input and output, making the
   325 parameters implicit and using the original short name.  See also
   326 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   327 entities from a monomorphic theory.
   328 
   329 Presently, abbreviations are only available 'in' a target locale, but
   330 not inherited by general import expressions.  Also note that
   331 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   332 'translations' in common applications.
   333 
   334 Concrete syntax is attached to specified constants in internal form,
   335 independently of name spaces.  The parse tree representation is
   336 slightly different -- use 'notation' instead of raw 'syntax', and
   337 'translations' with explicit "CONST" markup to accommodate this.
   338 
   339 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   340 the current context.  Print mode "no_abbrevs" prevents inversion of
   341 abbreviations on output.
   342 
   343 * Isar/locales: improved parameter handling:
   344 - use of locales "var" and "struct" no longer necessary;
   345 - parameter renamings are no longer required to be injective.
   346   This enables, for example, to define a locale for endomorphisms thus:
   347   locale endom = homom mult mult h.
   348 
   349 * Isar/locales: changed the way locales with predicates are defined.
   350 Instead of accumulating the specification, the imported expression is
   351 now an interpretation.  INCOMPATIBILITY: different normal form of
   352 locale expressions.  In particular, in interpretations of locales with
   353 predicates, goals repesenting already interpreted fragments are not
   354 removed automatically.  Use methods `intro_locales' and
   355 `unfold_locales'; see below.
   356 
   357 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   358 provide backward reasoning on locales predicates.  The methods are
   359 aware of interpretations and discharge corresponding goals.
   360 `intro_locales' is less aggressive then `unfold_locales' and does not
   361 unfold predicates to assumptions.
   362 
   363 * Isar/locales: the order in which locale fragments are accumulated
   364 has changed.  This enables to override declarations from fragments due
   365 to interpretations -- for example, unwanted simp rules.
   366 
   367 * Provers/induct: improved internal context management to support
   368 local fixes and defines on-the-fly.  Thus explicit meta-level
   369 connectives !! and ==> are rarely required anymore in inductive goals
   370 (using object-logic connectives for this purpose has been long
   371 obsolete anyway).  The subsequent proof patterns illustrate advanced
   372 techniques of natural induction; general datatypes and inductive sets
   373 work analogously (see also src/HOL/Lambda for realistic examples).
   374 
   375 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   376 parameters:
   377 
   378   lemma
   379     fixes n :: nat and x :: 'a
   380     assumes a: "A n x"
   381     shows "P n x"
   382     using a                     -- {* make induct insert fact a *}
   383   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   384     case 0
   385     show ?case sorry
   386   next
   387     case (Suc n)
   388     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   389     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   390     show ?case sorry
   391   qed
   392 
   393 (2) This is how to perform induction over ``expressions of a certain
   394 form'', using a locally defined inductive parameter n == "a x"
   395 together with strengthening (the latter is usually required to get
   396 sufficiently flexible induction hypotheses):
   397 
   398   lemma
   399     fixes a :: "'a => nat"
   400     assumes a: "A (a x)"
   401     shows "P (a x)"
   402     using a
   403   proof (induct n == "a x" arbitrary: x)
   404     ...
   405 
   406 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   407 particular technique.
   408 
   409 (3) This is how to perform existential reasoning ('obtains' or
   410 'obtain') by induction, while avoiding explicit object-logic
   411 encodings:
   412 
   413   lemma
   414     fixes n :: nat
   415     obtains x :: 'a where "P n x" and "Q n x"
   416   proof (induct n arbitrary: thesis)
   417     case 0
   418     obtain x where "P 0 x" and "Q 0 x" sorry
   419     then show thesis by (rule 0)
   420   next
   421     case (Suc n)
   422     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   423     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   424     then show thesis by (rule Suc.prems)
   425   qed
   426 
   427 Here the 'arbitrary: thesis' specification essentially modifies the
   428 scope of the formal thesis parameter, in order to the get the whole
   429 existence statement through the induction as expected.
   430 
   431 * Provers/induct: mutual induction rules are now specified as a list
   432 of rule sharing the same induction cases.  HOL packages usually
   433 provide foo_bar.inducts for mutually defined items foo and bar
   434 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   435 specify mutual induction rules differently, i.e. like this:
   436 
   437   (induct rule: foo_bar.inducts)
   438   (induct set: foo bar)
   439   (induct type: foo bar)
   440 
   441 The ML function ProjectRule.projections turns old-style rules into the
   442 new format.
   443 
   444 * Provers/induct: improved handling of simultaneous goals.  Instead of
   445 introducing object-level conjunction, the statement is now split into
   446 several conclusions, while the corresponding symbolic cases are
   447 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   448 explicitly.  For example:
   449 
   450   lemma
   451     fixes n :: nat
   452     shows "P n" and "Q n"
   453   proof (induct n)
   454     case 0 case 1
   455     show "P 0" sorry
   456   next
   457     case 0 case 2
   458     show "Q 0" sorry
   459   next
   460     case (Suc n) case 1
   461     note `P n` and `Q n`
   462     show "P (Suc n)" sorry
   463   next
   464     case (Suc n) case 2
   465     note `P n` and `Q n`
   466     show "Q (Suc n)" sorry
   467   qed
   468 
   469 The split into subcases may be deferred as follows -- this is
   470 particularly relevant for goal statements with local premises.
   471 
   472   lemma
   473     fixes n :: nat
   474     shows "A n ==> P n" and "B n ==> Q n"
   475   proof (induct n)
   476     case 0
   477     {
   478       case 1
   479       note `A 0`
   480       show "P 0" sorry
   481     next
   482       case 2
   483       note `B 0`
   484       show "Q 0" sorry
   485     }
   486   next
   487     case (Suc n)
   488     note `A n ==> P n` and `B n ==> Q n`
   489     {
   490       case 1
   491       note `A (Suc n)`
   492       show "P (Suc n)" sorry
   493     next
   494       case 2
   495       note `B (Suc n)`
   496       show "Q (Suc n)" sorry
   497     }
   498   qed
   499 
   500 If simultaneous goals are to be used with mutual rules, the statement
   501 needs to be structured carefully as a two-level conjunction, using
   502 lists of propositions separated by 'and':
   503 
   504   lemma
   505     shows "a : A ==> P1 a"
   506           "a : A ==> P2 a"
   507       and "b : B ==> Q1 b"
   508           "b : B ==> Q2 b"
   509           "b : B ==> Q3 b"
   510   proof (induct set: A B)
   511 
   512 * Provers/induct: support coinduction as well.  See
   513 src/HOL/Library/Coinductive_List.thy for various examples.
   514 
   515 * Attribute "symmetric" produces result with standardized schematic
   516 variables (index 0).  Potential INCOMPATIBILITY.
   517 
   518 * Simplifier: by default the simplifier trace only shows top level
   519 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   520 default. Thus there is less danger of being flooded by the trace. The
   521 trace indicates where parts have been suppressed.
   522   
   523 * Provers/classical: removed obsolete classical version of elim_format
   524 attribute; classical elim/dest rules are now treated uniformly when
   525 manipulating the claset.
   526 
   527 * Provers/classical: stricter checks to ensure that supplied intro,
   528 dest and elim rules are well-formed; dest and elim rules must have at
   529 least one premise.
   530 
   531 * Provers/classical: attributes dest/elim/intro take an optional
   532 weight argument for the rule (just as the Pure versions).  Weights are
   533 ignored by automated tools, but determine the search order of single
   534 rule steps.
   535 
   536 * Syntax: input syntax now supports dummy variable binding "%_. b",
   537 where the body does not mention the bound variable.  Note that dummy
   538 patterns implicitly depend on their context of bounds, which makes
   539 "{_. _}" match any set comprehension as expected.  Potential
   540 INCOMPATIBILITY -- parse translations need to cope with syntactic
   541 constant "_idtdummy" in the binding position.
   542 
   543 * Syntax: removed obsolete syntactic constant "_K" and its associated
   544 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   545 for example "A -> B" => "Pi A (%_. B)".
   546 
   547 * Pure: 'class_deps' command visualizes the subclass relation, using
   548 the graph browser tool.
   549 
   550 * Pure: 'print_theory' now suppresses entities with internal name
   551 (trailing "_") by default; use '!' option for full details.
   552 
   553 
   554 *** HOL ***
   555 
   556 * Code generator library theories:
   557   * Pretty_Int represents HOL integers by big integer literals in target
   558     languages.
   559   * Pretty_Char represents HOL characters by character literals in target
   560     languages.
   561   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   562     codes; includes Pretty_Int.
   563   * Executable_Set allows to generate code for finite sets using lists.
   564   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   565     denominator).
   566   * Executable_Real implements a subset of real numbers, namly those
   567     representable by rational numbers.
   568   * Efficient_Nat implements natural numbers by integers, which in general will
   569     result in higher efficency; pattern matching with 0/Suc is eliminated;
   570     includes Pretty_Int.
   571   * ML_String provides an additional datatype ml_string; in the HOL default
   572     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   573     of type ml_string are mapped to strings in SML.
   574   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   575     built-in integers.
   576 
   577 * New package for inductive predicates
   578 
   579   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   580 
   581     inductive
   582       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   583       for z_1 :: U_1 and ... and z_n :: U_m
   584     where
   585       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   586     | ...
   587 
   588   rather than
   589 
   590     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   591 
   592     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   593     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   594 
   595     inductive "s z_1 ... z_m"
   596     intros
   597       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   598       ...
   599 
   600   For backward compatibility, there is a wrapper allowing inductive
   601   sets to be defined with the new package via
   602 
   603     inductive_set
   604       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   605       for z_1 :: U_1 and ... and z_n :: U_m
   606     where
   607       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   608     | ...
   609 
   610   or
   611 
   612     inductive_set
   613       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   614       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   615       for z_1 :: U_1 and ... and z_n :: U_m
   616     where
   617       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   618     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   619     | ...
   620 
   621   if the additional syntax "p ..." is required.
   622 
   623   Many examples can be found in the subdirectories Auth, Bali, Induct,
   624   or MicroJava.
   625 
   626   INCOMPATIBILITIES:
   627 
   628   - Since declaration and definition of inductive sets or predicates
   629     is no longer separated, abbreviations involving the newly introduced
   630     sets or predicates must be specified together with the introduction
   631     rules after the "where" keyword (see example above), rather than before
   632     the actual inductive definition.
   633 
   634   - The variables in induction and elimination rules are now quantified
   635     in the order of their occurrence in the introduction rules, rather than
   636     in alphabetical order. Since this may break some proofs, these proofs
   637     either have to be repaired, e.g. by reordering the variables
   638     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   639 
   640       case (rule_i a_i_1 ... a_i_{k_i})
   641 
   642     or the old order of quantification has to be restored by explicitly adding
   643     meta-level quantifiers in the introduction rules, i.e.
   644 
   645       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   646 
   647   - The format of the elimination rules is now
   648 
   649       p z_1 ... z_m x_1 ... x_n ==>
   650         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   651         ==> ... ==> P
   652 
   653     for predicates and
   654 
   655       (x_1, ..., x_n) : s z_1 ... z_m ==>
   656         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   657         ==> ... ==> P
   658 
   659     for sets rather than
   660 
   661       x : s z_1 ... z_m ==>
   662         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   663         ==> ... ==> P
   664 
   665     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   666     or simplification with the split_paired_all rule) before the above elimination
   667     rule is applicable.
   668 
   669   - The elimination or case analysis rules for (mutually) inductive sets or
   670     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   671     "p_1_..._p_k.elims" is no longer available.
   672 
   673 * Method "metis" proves goals by applying the Metis general-purpose
   674 resolution prover.  Examples are in the directory MetisExamples.  See
   675 also http://gilith.com/software/metis/
   676   
   677 * Command 'sledgehammer' invokes external automatic theorem provers as
   678 background processes.  It generates calls to the "metis" method if
   679 successful. These can be pasted into the proof.  Users do not have to
   680 wait for the automatic provers to return.
   681 
   682 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   683   take their order into account, like in functional programming.
   684   Internally, this is translated into nested case-expressions; missing cases
   685   are added and mapped to the predefined constant "undefined". In complicated
   686   cases printing may no longer show the original input but the internal
   687   form. Lambda-abstractions allow the same form of pattern matching:
   688   "% pat1 => e1 | ..." is an abbreviation for
   689   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   690 
   691 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   692   is an abbreviation for "of_nat :: nat => int". The simplification rules
   693   for "of_nat" have been changed to work like "int" did previously.
   694   (potential INCOMPATIBILITY)
   695   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   696   - of_nat_diff and of_nat_mult are no longer default simp rules
   697 
   698 * Method "algebra" solves polynomial equations over (semi)rings using
   699   Groebner bases. The (semi)ring structure is defined by locales and
   700   the tool setup depends on that generic context. Installing the
   701   method for a specific type involves instantiating the locale and
   702   possibly adding declarations for computation on the coefficients.
   703   The method is already instantiated for natural numbers and for the
   704   axiomatic class of idoms with numerals.  See also the paper by
   705   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   706   underlying this architecture of context-aware proof-tools.
   707 
   708 * constant "List.op @" now named "List.append".  Use ML antiquotations
   709 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   710 possible incompatibilities when working on ML level.
   711 
   712 * Constant renames due to introduction of canonical name prefixing for
   713   class package:
   714 
   715     HOL.abs ~> HOL.minus_class.abs
   716     HOL.divide ~> HOL.divide_class.divide
   717     Nat.power ~> Nat.power_class.power
   718     Nat.size ~> Nat.size_class.size
   719     Numeral.number_of ~> Numeral.number_class.number_of
   720     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   721 
   722 * Rudimentary class target mechanism involves constant renames:
   723 
   724     Orderings.min ~> Orderings.ord_class.min
   725     Orderings.max ~> Orderings.ord_class.max
   726     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   727 
   728 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   729 
   730 * new constant "undefined" with axiom "undefined x = undefined"
   731 
   732 * new class "default" with associated constant "default"
   733 
   734 * new function listsum :: 'a list => 'a for arbitrary monoids.
   735   Special syntax: "SUM x <- xs. f x" (and latex variants)
   736 
   737 * new (input only) syntax for Haskell-like list comprehension, eg
   738   [(x,y). x <- xs, y <- ys, x ~= y]
   739   For details see List.thy.
   740 
   741 * The special syntax for function "filter" has changed from [x : xs. P] to
   742   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   743   and for uniformity. INCOMPATIBILITY
   744 
   745 * New lemma collection field_simps (an extension of ring_simps)
   746   for manipulating (in)equations involving division. Multiplies
   747   with all denominators that can be proved to be non-zero (in equations)
   748   or positive/negative (in inequations).
   749 
   750 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   751   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   752   Removed lemmas field_xyz in Ring_and_Field
   753   because they were subsumed by lemmas xyz.
   754 INCOMPATIBILITY.
   755 
   756 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   757   when generating code.
   758 
   759 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   760   when generating code.
   761 
   762 * Library/Commutative_Ring.thy: switched from recdef to function package;
   763   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   764 
   765 * Some steps towards more uniform lattice theory development in HOL.
   766 
   767     constants "meet" and "join" now named "inf" and "sup"
   768     constant "Meet" now named "Inf"
   769 
   770     classes "meet_semilorder" and "join_semilorder" now named
   771       "lower_semilattice" and "upper_semilattice"
   772     class "lorder" now named "lattice"
   773     class "comp_lat" now named "complete_lattice"
   774 
   775     Instantiation of lattice classes allows explicit definitions
   776     for "inf" and "sup" operations.
   777 
   778   INCOMPATIBILITY.  Theorem renames:
   779 
   780     meet_left_le            ~> inf_le1
   781     meet_right_le           ~> inf_le2
   782     join_left_le            ~> sup_ge1
   783     join_right_le           ~> sup_ge2
   784     meet_join_le            ~> inf_sup_ord
   785     le_meetI                ~> le_infI
   786     join_leI                ~> le_supI
   787     le_meet                 ~> le_inf_iff
   788     le_join                 ~> ge_sup_conv
   789     meet_idempotent         ~> inf_idem
   790     join_idempotent         ~> sup_idem
   791     meet_comm               ~> inf_commute
   792     join_comm               ~> sup_commute
   793     meet_leI1               ~> le_infI1
   794     meet_leI2               ~> le_infI2
   795     le_joinI1               ~> le_supI1
   796     le_joinI2               ~> le_supI2
   797     meet_assoc              ~> inf_assoc
   798     join_assoc              ~> sup_assoc
   799     meet_left_comm          ~> inf_left_commute
   800     meet_left_idempotent    ~> inf_left_idem
   801     join_left_comm          ~> sup_left_commute
   802     join_left_idempotent    ~> sup_left_idem
   803     meet_aci                ~> inf_aci
   804     join_aci                ~> sup_aci
   805     le_def_meet             ~> le_iff_inf
   806     le_def_join             ~> le_iff_sup
   807     join_absorp2            ~> sup_absorb2
   808     join_absorp1            ~> sup_absorb1
   809     meet_absorp1            ~> inf_absorb1
   810     meet_absorp2            ~> inf_absorb2
   811     meet_join_absorp        ~> inf_sup_absorb
   812     join_meet_absorp        ~> sup_inf_absorb
   813     distrib_join_le         ~> distrib_sup_le
   814     distrib_meet_le         ~> distrib_inf_le
   815 
   816     add_meet_distrib_left   ~> add_inf_distrib_left
   817     add_join_distrib_left   ~> add_sup_distrib_left
   818     is_join_neg_meet        ~> is_join_neg_inf
   819     is_meet_neg_join        ~> is_meet_neg_sup
   820     add_meet_distrib_right  ~> add_inf_distrib_right
   821     add_join_distrib_right  ~> add_sup_distrib_right
   822     add_meet_join_distribs  ~> add_sup_inf_distribs
   823     join_eq_neg_meet        ~> sup_eq_neg_inf
   824     meet_eq_neg_join        ~> inf_eq_neg_sup
   825     add_eq_meet_join        ~> add_eq_inf_sup
   826     meet_0_imp_0            ~> inf_0_imp_0
   827     join_0_imp_0            ~> sup_0_imp_0
   828     meet_0_eq_0             ~> inf_0_eq_0
   829     join_0_eq_0             ~> sup_0_eq_0
   830     neg_meet_eq_join        ~> neg_inf_eq_sup
   831     neg_join_eq_meet        ~> neg_sup_eq_inf
   832     join_eq_if              ~> sup_eq_if
   833 
   834     mono_meet               ~> mono_inf
   835     mono_join               ~> mono_sup
   836     meet_bool_eq            ~> inf_bool_eq
   837     join_bool_eq            ~> sup_bool_eq
   838     meet_fun_eq             ~> inf_fun_eq
   839     join_fun_eq             ~> sup_fun_eq
   840     meet_set_eq             ~> inf_set_eq
   841     join_set_eq             ~> sup_set_eq
   842     meet1_iff               ~> inf1_iff
   843     meet2_iff               ~> inf2_iff
   844     meet1I                  ~> inf1I
   845     meet2I                  ~> inf2I
   846     meet1D1                 ~> inf1D1
   847     meet2D1                 ~> inf2D1
   848     meet1D2                 ~> inf1D2
   849     meet2D2                 ~> inf2D2
   850     meet1E                  ~> inf1E
   851     meet2E                  ~> inf2E
   852     join1_iff               ~> sup1_iff
   853     join2_iff               ~> sup2_iff
   854     join1I1                 ~> sup1I1
   855     join2I1                 ~> sup2I1
   856     join1I1                 ~> sup1I1
   857     join2I2                 ~> sup1I2
   858     join1CI                 ~> sup1CI
   859     join2CI                 ~> sup2CI
   860     join1E                  ~> sup1E
   861     join2E                  ~> sup2E
   862 
   863     is_meet_Meet            ~> is_meet_Inf
   864     Meet_bool_def           ~> Inf_bool_def
   865     Meet_fun_def            ~> Inf_fun_def
   866     Meet_greatest           ~> Inf_greatest
   867     Meet_lower              ~> Inf_lower
   868     Meet_set_def            ~> Inf_set_def
   869 
   870     listsp_meetI            ~> listsp_infI
   871     listsp_meet_eq          ~> listsp_inf_eq
   872 
   873     meet_min                ~> inf_min
   874     join_max                ~> sup_max
   875 
   876 * Classes "order" and "linorder": facts "refl", "trans" and
   877 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   878 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   879 
   880 * Classes "order" and "linorder": 
   881 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   882 proofs changed.
   883 
   884 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   885 INCOMPATIBILITY.
   886 
   887 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   888 INCOMPATIBILITY.
   889 
   890 * Added syntactic class "size"; overloaded constant "size" now has
   891 type "'a::size ==> bool"
   892 
   893 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   894 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   895 
   896 * Added method "lexicographic_order" automatically synthesizes
   897 termination relations as lexicographic combinations of size measures
   898 -- 'function' package.
   899 
   900 * HOL/records: generalised field-update to take a function on the
   901 field rather than the new value: r(|A := x|) is translated to A_update
   902 (K x) r The K-combinator that is internally used is called K_record.
   903 INCOMPATIBILITY: Usage of the plain update functions has to be
   904 adapted.
   905  
   906 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   907 0 * x = 0, which are required for a semiring.  Richer structures do
   908 not inherit from semiring_0 anymore, because this property is a
   909 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   910 semiring_0, there is more to prove, but this is mostly trivial.
   911 
   912 * axclass "recpower" was generalized to arbitrary monoids, not just
   913 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   914 commutativity or a semiring property, add the corresponding classes.
   915 
   916 * Unified locale partial_order with class definition (cf. theory
   917 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   918 
   919 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   920 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   921 Isar level, use abbreviations instead.
   922 
   923 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   924 rarely occuring name references (e.g. ``List.op mem.simps'') require
   925 renaming (e.g. ``List.memberl.simps'').
   926 
   927 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   928 INCOMPATIBILITY.
   929 
   930 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   931 
   932 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   933 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   934 significant changes for setting up numeral syntax for types:
   935 
   936   - new constants Numeral.pred and Numeral.succ instead
   937       of former Numeral.bin_pred and Numeral.bin_succ.
   938   - Use integer operations instead of bin_add, bin_mult and so on.
   939   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   940   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   941 
   942 See HOL/Integ/IntArith.thy for an example setup.
   943 
   944 * New top level command 'normal_form' computes the normal form of a
   945 term that may contain free variables. For example ``normal_form
   946 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   947 suitable for heavy-duty computations because the functions are
   948 compiled to ML first.
   949 
   950 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   951 25 like -->); output depends on the "iff" print_mode, the default is
   952 "A = B" (with priority 50).
   953 
   954 * Renamed constants in HOL.thy and Orderings.thy:
   955     op +   ~> HOL.plus_class.plus
   956     op -   ~> HOL.minus_class.minus
   957     uminus ~> HOL.minus_class.uminus
   958     abs    ~> HOL.abs_class.abs
   959     op *   ~> HOL.times_class.times
   960     op <   ~> HOL.ord_class.less
   961     op <=  ~> HOL.ord_class.less_eq
   962 
   963 Adaptions may be required in the following cases:
   964 
   965 a) User-defined constants using any of the names "plus", "minus", "times",
   966 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   967 may go wrong.
   968 INCOMPATIBILITY: use more specific names.
   969 
   970 b) Variables named "plus", "minus", "times", "less", "less_eq"
   971 INCOMPATIBILITY: use more specific names.
   972 
   973 c) Permutative equations (e.g. "a + b = b + a")
   974 Since the change of names also changes the order of terms, permutative
   975 rewrite rules may get applied in a different order. Experience shows that
   976 this is rarely the case (only two adaptions in the whole Isabelle
   977 distribution).
   978 INCOMPATIBILITY: rewrite proofs
   979 
   980 d) ML code directly refering to constant names
   981 This in general only affects hand-written proof tactics, simprocs and so on.
   982 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   983 of const_name ML antiquotations.
   984 
   985 * Relations less (<) and less_eq (<=) are also available on type bool.
   986 Modified syntax to disallow nesting without explicit parentheses,
   987 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   988 
   989 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   990 
   991 * Relation composition operator "op O" now has precedence 75 and binds
   992 stronger than union and intersection. INCOMPATIBILITY.
   993 
   994 * The old set interval syntax "{m..n(}" (and relatives) has been
   995 removed.  Use "{m..<n}" (and relatives) instead.
   996 
   997 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   998 "t = s" to False (by simproc "neq_simproc").  For backward
   999 compatibility this can be disabled by ML "reset use_neq_simproc".
  1000 
  1001 * "m dvd n" where m and n are numbers is evaluated to True/False by
  1002 simp.
  1003 
  1004 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
  1005 
  1006 * Theorem setsum_mult renamed to setsum_right_distrib.
  1007 
  1008 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1009 ``rule'' method.
  1010 
  1011 * Reimplemented methods ``sat'' and ``satx'', with several
  1012 improvements: goals no longer need to be stated as "<prems> ==>
  1013 False", equivalences (i.e. "=" on type bool) are handled, variable
  1014 names of the form "lit_<n>" are no longer reserved, significant
  1015 speedup.
  1016 
  1017 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1018 zChaff is still supported as well.
  1019 
  1020 * 'inductive' and 'datatype': provide projections of mutual rules,
  1021 bundled as foo_bar.inducts;
  1022 
  1023 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1024 Library.
  1025 
  1026 * Library: moved theory Accessible_Part to main HOL.
  1027 
  1028 * Library: added theory Coinductive_List of potentially infinite lists
  1029 as greatest fixed-point.
  1030 
  1031 * Library: added theory AssocList which implements (finite) maps as
  1032 association lists.
  1033 
  1034 * Added proof method ``evaluation'' for efficiently solving a goal
  1035 (i.e. a boolean expression) by compiling it to ML. The goal is
  1036 "proved" (via an oracle) if it evaluates to True.
  1037 
  1038 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1039 also when invoked by the simplifier.  This results in the simplifier
  1040 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1041 fast_arith_split_limit to 0 to obtain the old behavior.
  1042 
  1043 * Support for hex (0x20) and binary (0b1001) numerals.
  1044 
  1045 * New method: reify eqs (t), where eqs are equations for an
  1046 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1047 parameter, computes a term s::'b and a list xs::'a list and proves the
  1048 theorem I xs s = t. This is also known as reification or quoting. The
  1049 resulting theorem is applied to the subgoal to substitute t with I xs
  1050 s.  If t is omitted, the subgoal itself is reified.
  1051 
  1052 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1053 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1054 where f is supposed to be a computable function (in the sense of code
  1055 generattion). The method uses reify to compute s and xs as above then
  1056 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1057 r and finally gets the theorem t = r, which is again applied to the
  1058 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1059 
  1060 * Reflection: Automatic reification now handels binding, an example
  1061 is available in HOL/ex/ReflectionEx.thy
  1062 
  1063 
  1064 *** HOL-Algebra ***
  1065 
  1066 * Formalisation of ideals and the quotient construction over rings.
  1067 
  1068 * Order and lattice theory no longer based on records.
  1069 INCOMPATIBILITY.
  1070 
  1071 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1072 greatest_closed.  INCOMPATIBILITY.
  1073 
  1074 * Method algebra is now set up via an attribute.  For examples see
  1075 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1076 of algebraic structures.
  1077 
  1078 * Renamed theory CRing to Ring.
  1079 
  1080 
  1081 *** HOL-Complex ***
  1082 
  1083 * Theory Real: new method ferrack implements quantifier elimination
  1084 for linear arithmetic over the reals. The quantifier elimination
  1085 feature is used only for decision, for compatibility with arith. This
  1086 means a goal is either solved or left unchanged, no simplification.
  1087 
  1088 * Hyperreal: Functions root and sqrt are now defined on negative real
  1089 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1090 Nonnegativity side conditions have been removed from many lemmas, so
  1091 that more subgoals may now be solved by simplification; potential
  1092 INCOMPATIBILITY.
  1093 
  1094 * Real: New axiomatic classes formalize real normed vector spaces and
  1095 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1096 and norm :: 'a => real.
  1097 
  1098 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1099 from reals into other types. The overloaded constant Reals :: 'a set
  1100 is now defined as range of_real; potential INCOMPATIBILITY.
  1101 
  1102 * Real: ML code generation is supported now and hence also quickcheck.
  1103 Reals are implemented as arbitrary precision rationals.
  1104 
  1105 * Hyperreal: Several constants that previously worked only for the
  1106 reals have been generalized, so they now work over arbitrary vector
  1107 spaces. Type annotations may need to be added in some cases; potential
  1108 INCOMPATIBILITY.
  1109 
  1110   Infinitesimal  :: ('a::real_normed_vector) star set
  1111   HFinite        :: ('a::real_normed_vector) star set
  1112   HInfinite      :: ('a::real_normed_vector) star set
  1113   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1114   monad          :: ('a::real_normed_vector) star => 'a star set
  1115   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1116   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1117   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1118   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1119   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1120   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1121   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1122   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1123   sgn            :: 'a::real_normed_vector => 'a
  1124   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1125 
  1126 * Complex: Some complex-specific constants are now abbreviations for
  1127 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1128 hnorm.  Other constants have been entirely removed in favor of the
  1129 polymorphic versions (INCOMPATIBILITY):
  1130 
  1131   approx        <-- capprox
  1132   HFinite       <-- CFinite
  1133   HInfinite     <-- CInfinite
  1134   Infinitesimal <-- CInfinitesimal
  1135   monad         <-- cmonad
  1136   galaxy        <-- cgalaxy
  1137   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1138   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1139   (ns)deriv     <-- (ns)cderiv
  1140 
  1141 
  1142 *** ML ***
  1143 
  1144 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1145 
  1146 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1147 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1148 init only required for impure data.  INCOMPATIBILITY: empty really
  1149 need to be empty (no dependencies on theory content!)
  1150 
  1151 * ML within Isar: antiquotations allow to embed statically-checked
  1152 formal entities in the source, referring to the context available at
  1153 compile-time.  For example:
  1154 
  1155 ML {* @{typ "'a => 'b"} *}
  1156 ML {* @{term "%x. x"} *}
  1157 ML {* @{prop "x == y"} *}
  1158 ML {* @{ctyp "'a => 'b"} *}
  1159 ML {* @{cterm "%x. x"} *}
  1160 ML {* @{cprop "x == y"} *}
  1161 ML {* @{thm asm_rl} *}
  1162 ML {* @{thms asm_rl} *}
  1163 ML {* @{const_name c} *}
  1164 ML {* @{const_syntax c} *}
  1165 ML {* @{context} *}
  1166 ML {* @{theory} *}
  1167 ML {* @{theory Pure} *}
  1168 ML {* @{simpset} *}
  1169 ML {* @{claset} *}
  1170 ML {* @{clasimpset} *}
  1171 
  1172 The same works for sources being ``used'' within an Isar context.
  1173 
  1174 * ML in Isar: improved error reporting; extra verbosity with
  1175 Toplevel.debug enabled.
  1176 
  1177 * Pure/library:
  1178 
  1179   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1180   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1181 
  1182 The semantics of "burrow" is: "take a function with *simulatanously*
  1183 transforms a list of value, and apply it *simulatanously* to a list of
  1184 list of values of the appropriate type". Compare this with "map" which
  1185 would *not* apply its argument function simulatanously but in
  1186 sequence; "fold_burrow" has an additional context.
  1187 
  1188 * Pure/library: functions map2 and fold2 with curried syntax for
  1189 simultanous mapping and folding:
  1190 
  1191     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1192     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1193 
  1194 * Pure/library: indexed lists - some functions in the Isabelle library
  1195 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1196 given more convenient names and signatures reminiscent of similar
  1197 functions for alists, tables, etc:
  1198 
  1199   val nth: 'a list -> int -> 'a 
  1200   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1201   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1202 
  1203 Note that fold_index starts counting at index 0, not 1 like foldln
  1204 used to.
  1205 
  1206 * Pure/library: added general ``divide_and_conquer'' combinator on
  1207 lists.
  1208 
  1209 * Pure/General/table.ML: the join operations now works via exceptions
  1210 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1211 admits slightly more efficient complex applications.
  1212 
  1213 * Pure: datatype Context.generic joins theory/Proof.context and
  1214 provides some facilities for code that works in either kind of
  1215 context, notably GenericDataFun for uniform theory and proof data.
  1216 
  1217 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1218 use Context.generic instead of just theory.
  1219 
  1220 * Pure: simplified internal attribute type, which is now always
  1221 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1222 vs. local (Proof.context) attributes have been discontinued, while
  1223 minimizing code duplication.  Thm.rule_attribute and
  1224 Thm.declaration_attribute build canonical attributes; see also
  1225 structure Context for further operations on Context.generic, notably
  1226 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1227 declarations and definitions.
  1228 
  1229 * Pure/kernel: consts certification ignores sort constraints given in
  1230 signature declarations.  (This information is not relevant to the
  1231 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1232 potential INCOMPATIBILITY.
  1233 
  1234 * Pure: axiomatic type classes are now purely definitional, with
  1235 explicit proofs of class axioms and super class relations performed
  1236 internally.  See Pure/axclass.ML for the main internal interfaces --
  1237 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1238 AxClass.axiomatize_class/classrel/arity supercede
  1239 Sign.add_classes/classrel/arities.
  1240 
  1241 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1242 global/local versions on theory vs. Proof.context have been
  1243 discontinued; Attrib.syntax and Method.syntax have been adapted
  1244 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1245 attributes, methods, etc.
  1246 
  1247 * Pure: several functions of signature "... -> theory -> theory * ..."
  1248 have been reoriented to "... -> theory -> ... * theory" in order to
  1249 allow natural usage in combination with the ||>, ||>>, |-> and
  1250 fold_map combinators.
  1251 
  1252 * Pure: official theorem names (closed derivations) and additional
  1253 comments (tags) are now strictly separate.  Name hints -- which are
  1254 maintained as tags -- may be attached any time without affecting the
  1255 derivation.
  1256 
  1257 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1258 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1259 achieve the old behaviour.
  1260 
  1261 * Pure: the "Goal" constant is now called "prop", supporting a
  1262 slightly more general idea of ``protecting'' meta-level rule
  1263 statements.
  1264 
  1265 * Pure: Logic.(un)varify only works in a global context, which is now
  1266 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1267 Logic.legacy_(un)varify as temporary workaround.
  1268 
  1269 * Pure: structure Name provides scalable operations for generating
  1270 internal variable names, notably Name.variants etc.  This replaces
  1271 some popular functions from term.ML:
  1272 
  1273   Term.variant		->  Name.variant
  1274   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1275   Term.invent_names	->  Name.invent_list
  1276 
  1277 Note that low-level renaming rarely occurs in new code -- operations
  1278 from structure Variable are used instead (see below).
  1279 
  1280 * Pure: structure Variable provides fundamental operations for proper
  1281 treatment of fixed/schematic variables in a context.  For example,
  1282 Variable.import introduces fixes for schematics of given facts and
  1283 Variable.export reverses the effect (up to renaming) -- this replaces
  1284 various freeze_thaw operations.
  1285 
  1286 * Pure: structure Goal provides simple interfaces for
  1287 init/conclude/finish and tactical prove operations (replacing former
  1288 Tactic.prove).  Goal.prove is the canonical way to prove results
  1289 within a given context; Goal.prove_global is a degraded version for
  1290 theory level goals, including a global Drule.standard.  Note that
  1291 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1292 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1293 in a locale context).
  1294 
  1295 * Isar: simplified treatment of user-level errors, using exception
  1296 ERROR of string uniformly.  Function error now merely raises ERROR,
  1297 without any side effect on output channels.  The Isar toplevel takes
  1298 care of proper display of ERROR exceptions.  ML code may use plain
  1299 handle/can/try; cat_error may be used to concatenate errors like this:
  1300 
  1301   ... handle ERROR msg => cat_error msg "..."
  1302 
  1303 Toplevel ML code (run directly or through the Isar toplevel) may be
  1304 embedded into the Isar toplevel with exception display/debug like
  1305 this:
  1306 
  1307   Isar.toplevel (fn () => ...)
  1308 
  1309 INCOMPATIBILITY, removed special transform_error facilities, removed
  1310 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1311 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1312 -- use plain ERROR instead.
  1313 
  1314 * Isar: theory setup now has type (theory -> theory), instead of a
  1315 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1316 
  1317 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1318 subject to ProofContext.debug/verbose flags.
  1319 
  1320 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1321 theory before entering a proof state.  Transactions now always see a
  1322 quasi-functional intermediate checkpoint, both in interactive and
  1323 batch mode.
  1324 
  1325 * Simplifier: the simpset of a running simplification process now
  1326 contains a proof context (cf. Simplifier.the_context), which is the
  1327 very context that the initial simpset has been retrieved from (by
  1328 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1329 (solver, looper etc.) may depend on arbitrary proof data.
  1330 
  1331 * Simplifier.inherit_context inherits the proof context (plus the
  1332 local bounds) of the current simplification process; any simproc
  1333 etc. that calls the Simplifier recursively should do this!  Removed
  1334 former Simplifier.inherit_bounds, which is already included here --
  1335 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1336 specify an explicit context using Simplifier.context/theory_context.
  1337 
  1338 * Simplifier/Classical Reasoner: more abstract interfaces
  1339 change_simpset/claset for modifying the simpset/claset reference of a
  1340 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1341 INCOMPATIBILITY.
  1342 
  1343 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1344 "Trueprop" etc.
  1345 
  1346 
  1347 *** System ***
  1348 
  1349 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1350 locations -- now includes the Isabelle version identifier as well.
  1351 This simplifies use of multiple Isabelle installations.
  1352 
  1353 * isabelle-process: option -S (secure mode) disables some critical
  1354 operations, notably runtime compilation and evaluation of ML source
  1355 code.
  1356 
  1357 
  1358 New in Isabelle2005 (October 2005)
  1359 ----------------------------------
  1360 
  1361 *** General ***
  1362 
  1363 * Theory headers: the new header syntax for Isar theories is
  1364 
  1365   theory <name>
  1366   imports <theory1> ... <theoryN>
  1367   uses <file1> ... <fileM>
  1368   begin
  1369 
  1370 where the 'uses' part is optional.  The previous syntax
  1371 
  1372   theory <name> = <theory1> + ... + <theoryN>:
  1373 
  1374 will disappear in the next release.  Use isatool fixheaders to convert
  1375 existing theory files.  Note that there is no change in ancient
  1376 non-Isar theories now, but these will disappear soon.
  1377 
  1378 * Theory loader: parent theories can now also be referred to via
  1379 relative and absolute paths.
  1380 
  1381 * Command 'find_theorems' searches for a list of criteria instead of a
  1382 list of constants. Known criteria are: intro, elim, dest, name:string,
  1383 simp:term, and any term. Criteria can be preceded by '-' to select
  1384 theorems that do not match. Intro, elim, dest select theorems that
  1385 match the current goal, name:s selects theorems whose fully qualified
  1386 name contain s, and simp:term selects all simplification rules whose
  1387 lhs match term.  Any other term is interpreted as pattern and selects
  1388 all theorems matching the pattern. Available in ProofGeneral under
  1389 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1390 
  1391   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1392 
  1393 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1394 matching the current goal as introduction rule and not having "HOL."
  1395 in their name (i.e. not being defined in theory HOL).
  1396 
  1397 * Command 'thms_containing' has been discontinued in favour of
  1398 'find_theorems'; INCOMPATIBILITY.
  1399 
  1400 * Communication with Proof General is now 8bit clean, which means that
  1401 Unicode text in UTF-8 encoding may be used within theory texts (both
  1402 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1403 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1404 
  1405   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1406   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1407 
  1408 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1409 Classical Reasoner.  Typical big applications run around 2 times
  1410 faster.
  1411 
  1412 
  1413 *** Document preparation ***
  1414 
  1415 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1416 of raw sources.  Only those symbols that do not require additional
  1417 LaTeX packages (depending on comments in isabellesym.sty) are
  1418 displayed properly, everything else is left verbatim.  isatool display
  1419 and isatool print are used as front ends (these are subject to the
  1420 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1421 
  1422 * Command tags control specific markup of certain regions of text,
  1423 notably folding and hiding.  Predefined tags include "theory" (for
  1424 theory begin and end), "proof" for proof commands, and "ML" for
  1425 commands involving ML code; the additional tags "visible" and
  1426 "invisible" are unused by default.  Users may give explicit tag
  1427 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1428 interpretation of tags is determined by the LaTeX job during document
  1429 preparation: see option -V of isatool usedir, or options -n and -t of
  1430 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1431 \isadroptag.
  1432 
  1433 Several document versions may be produced at the same time via isatool
  1434 usedir (the generated index.html will link all of them).  Typical
  1435 specifications include ''-V document=theory,proof,ML'' to present
  1436 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1437 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1438 these parts without any formal replacement text.  The Isabelle site
  1439 default settings produce ''document'' and ''outline'' versions as
  1440 specified above.
  1441 
  1442 * Several new antiquotations:
  1443 
  1444   @{term_type term} prints a term with its type annotated;
  1445 
  1446   @{typeof term} prints the type of a term;
  1447 
  1448   @{const const} is the same as @{term const}, but checks that the
  1449   argument is a known logical constant;
  1450 
  1451   @{term_style style term} and @{thm_style style thm} print a term or
  1452   theorem applying a "style" to it
  1453 
  1454   @{ML text}
  1455 
  1456 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1457 definitions, equations, inequations etc., 'concl' printing only the
  1458 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1459 to print the specified premise.  TermStyle.add_style provides an ML
  1460 interface for introducing further styles.  See also the "LaTeX Sugar"
  1461 document practical applications.  The ML antiquotation prints
  1462 type-checked ML expressions verbatim.
  1463 
  1464 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1465 and 'text' support optional locale specification '(in loc)', which
  1466 specifies the default context for interpreting antiquotations.  For
  1467 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1468 
  1469 * Option 'locale=NAME' of antiquotations specifies an alternative
  1470 context interpreting the subsequent argument.  For example: @{thm
  1471 [locale=lattice] inf_assoc}.
  1472 
  1473 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1474 a proof context.
  1475 
  1476 * Proper output of antiquotations for theory commands involving a
  1477 proof context (such as 'locale' or 'theorem (in loc) ...').
  1478 
  1479 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1480 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1481 
  1482 * isatool usedir: new option -C (default true) controls whether option
  1483 -D should include a copy of the original document directory; -C false
  1484 prevents unwanted effects such as copying of administrative CVS data.
  1485 
  1486 
  1487 *** Pure ***
  1488 
  1489 * Considerably improved version of 'constdefs' command.  Now performs
  1490 automatic type-inference of declared constants; additional support for
  1491 local structure declarations (cf. locales and HOL records), see also
  1492 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1493 sequential dependencies of definitions within a single 'constdefs'
  1494 section; moreover, the declared name needs to be an identifier.  If
  1495 all fails, consider to fall back on 'consts' and 'defs' separately.
  1496 
  1497 * Improved indexed syntax and implicit structures.  First of all,
  1498 indexed syntax provides a notational device for subscripted
  1499 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1500 expressions.  Secondly, in a local context with structure
  1501 declarations, number indexes \<^sub>n or the empty index (default
  1502 number 1) refer to a certain fixed variable implicitly; option
  1503 show_structs controls printing of implicit structures.  Typical
  1504 applications of these concepts involve record types and locales.
  1505 
  1506 * New command 'no_syntax' removes grammar declarations (and
  1507 translations) resulting from the given syntax specification, which is
  1508 interpreted in the same manner as for the 'syntax' command.
  1509 
  1510 * 'Advanced' translation functions (parse_translation etc.) may depend
  1511 on the signature of the theory context being presently used for
  1512 parsing/printing, see also isar-ref manual.
  1513 
  1514 * Improved 'oracle' command provides a type-safe interface to turn an
  1515 ML expression of type theory -> T -> term into a primitive rule of
  1516 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1517 is already included here); see also FOL/ex/IffExample.thy;
  1518 INCOMPATIBILITY.
  1519 
  1520 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1521 before); "cI" is no longer bound, use "c.intro" instead.
  1522 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1523 axclasses vs. locales.
  1524 
  1525 * Improved internal renaming of symbolic identifiers -- attach primes
  1526 instead of base 26 numbers.
  1527 
  1528 * New flag show_question_marks controls printing of leading question
  1529 marks in schematic variable names.
  1530 
  1531 * In schematic variable names, *any* symbol following \<^isub> or
  1532 \<^isup> is now treated as part of the base name.  For example, the
  1533 following works without printing of awkward ".0" indexes:
  1534 
  1535   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1536     by simp
  1537 
  1538 * Inner syntax includes (*(*nested*) comments*).
  1539 
  1540 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1541 annotations as "(00...)".
  1542 
  1543 * Clear separation of logical types and nonterminals, where the latter
  1544 may only occur in 'syntax' specifications or type abbreviations.
  1545 Before that distinction was only partially implemented via type class
  1546 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1547 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1548 exotic syntax specifications may require further adaption
  1549 (e.g. Cube/Cube.thy).
  1550 
  1551 * Removed obsolete type class "logic", use the top sort {} instead.
  1552 Note that non-logical types should be declared as 'nonterminals'
  1553 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1554 specifications.
  1555 
  1556 * Attributes 'induct' and 'cases': type or set names may now be
  1557 locally fixed variables as well.
  1558 
  1559 * Simplifier: can now control the depth to which conditional rewriting
  1560 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1561 Limit.
  1562 
  1563 * Simplifier: simplification procedures may now take the current
  1564 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1565 interface), which is very useful for calling the Simplifier
  1566 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1567 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1568 low-level mk_simproc no longer applies Logic.varify internally, to
  1569 allow for use in a context of fixed variables.
  1570 
  1571 * thin_tac now works even if the assumption being deleted contains !!
  1572 or ==>.  More generally, erule now works even if the major premise of
  1573 the elimination rule contains !! or ==>.
  1574 
  1575 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1576 
  1577 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1578 from Pure, which contains all common declarations already.  Both
  1579 theories are defined via plain Isabelle/Isar .thy files.
  1580 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1581 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1582 use isatool fixcpure to adapt your theory and ML sources.
  1583 
  1584 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1585 selections of theorems in named facts via index ranges.
  1586 
  1587 * 'print_theorems': in theory mode, really print the difference
  1588 wrt. the last state (works for interactive theory development only),
  1589 in proof mode print all local facts (cf. 'print_facts');
  1590 
  1591 * 'hide': option '(open)' hides only base names.
  1592 
  1593 * More efficient treatment of intermediate checkpoints in interactive
  1594 theory development.
  1595 
  1596 * Code generator is now invoked via code_module (incremental code
  1597 generation) and code_library (modular code generation, ML structures
  1598 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1599 must be quoted when used as identifiers.
  1600 
  1601 * New 'value' command for reading, evaluating and printing terms using
  1602 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1603 quoted when used as identifier.
  1604 
  1605 
  1606 *** Locales ***
  1607 
  1608 * New commands for the interpretation of locale expressions in
  1609 theories (1), locales (2) and proof contexts (3).  These generate
  1610 proof obligations from the expression specification.  After the
  1611 obligations have been discharged, theorems of the expression are added
  1612 to the theory, target locale or proof context.  The synopsis of the
  1613 commands is a follows:
  1614 
  1615   (1) interpretation expr inst
  1616   (2) interpretation target < expr
  1617   (3) interpret expr inst
  1618 
  1619 Interpretation in theories and proof contexts require a parameter
  1620 instantiation of terms from the current context.  This is applied to
  1621 specifications and theorems of the interpreted expression.
  1622 Interpretation in locales only permits parameter renaming through the
  1623 locale expression.  Interpretation is smart in that interpretations
  1624 that are active already do not occur in proof obligations, neither are
  1625 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1626 inspect active interpretations of a particular locale.  For details,
  1627 see the Isar Reference manual.  Examples can be found in
  1628 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1629 
  1630 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1631 'interpret' instead.
  1632 
  1633 * New context element 'constrains' for adding type constraints to
  1634 parameters.
  1635 
  1636 * Context expressions: renaming of parameters with syntax
  1637 redeclaration.
  1638 
  1639 * Locale declaration: 'includes' disallowed.
  1640 
  1641 * Proper static binding of attribute syntax -- i.e. types / terms /
  1642 facts mentioned as arguments are always those of the locale definition
  1643 context, independently of the context of later invocations.  Moreover,
  1644 locale operations (renaming and type / term instantiation) are applied
  1645 to attribute arguments as expected.
  1646 
  1647 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1648 actual attributes; rare situations may require Attrib.attribute to
  1649 embed those attributes into Attrib.src that lack concrete syntax.
  1650 Attribute implementations need to cooperate properly with the static
  1651 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1652 Attrib.XXX_thm etc. already do the right thing without further
  1653 intervention.  Only unusual applications -- such as "where" or "of"
  1654 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1655 on the context and the facts involved -- may have to assign parsed
  1656 values to argument tokens explicitly.
  1657 
  1658 * Changed parameter management in theorem generation for long goal
  1659 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1660 theorem statement in rare situations.
  1661 
  1662 * Locale inspection command 'print_locale' omits notes elements.  Use
  1663 'print_locale!' to have them included in the output.
  1664 
  1665 
  1666 *** Provers ***
  1667 
  1668 * Provers/hypsubst.ML: improved version of the subst method, for
  1669 single-step rewriting: it now works in bound variable contexts. New is
  1670 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1671 rewrite a different subterm than the original subst method, which is
  1672 still available as 'simplesubst'.
  1673 
  1674 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1675 and quasi orders.
  1676 
  1677 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1678 reflexive-transitive closure of relations.
  1679 
  1680 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1681 limit (previously hard-coded with a value of 20) user-definable.
  1682 
  1683 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1684 is peformed already.  Object-logics merely need to finish their
  1685 initial simpset configuration as before.  INCOMPATIBILITY.
  1686 
  1687 
  1688 *** HOL ***
  1689 
  1690 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1691 
  1692   syntax (epsilon)
  1693     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1694 
  1695 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1696 and x-symbol; use option '-m epsilon' to get it actually printed.
  1697 Moreover, the mathematically important symbolic identifier \<epsilon>
  1698 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1699 
  1700 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1701 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1702 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1703 support corresponding Isar calculations.
  1704 
  1705 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1706 instead of ":".
  1707 
  1708 * theory SetInterval: changed the syntax for open intervals:
  1709 
  1710   Old       New
  1711   {..n(}    {..<n}
  1712   {)n..}    {n<..}
  1713   {m..n(}   {m..<n}
  1714   {)m..n}   {m<..n}
  1715   {)m..n(}  {m<..<n}
  1716 
  1717 The old syntax is still supported but will disappear in the next
  1718 release.  For conversion use the following Emacs search and replace
  1719 patterns (these are not perfect but work quite well):
  1720 
  1721   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1722   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1723 
  1724 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1725 equalities in commutative rings; method 'algebra' provides a generic
  1726 interface.
  1727 
  1728 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1729 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1730 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1731 be a tuple pattern.
  1732 
  1733 Some new syntax forms are available:
  1734 
  1735   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1736   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1737   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1738   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1739 
  1740 The latter form "\<Sum>x < k. e" used to be based on a separate
  1741 function "Summation", which has been discontinued.
  1742 
  1743 * theory Finite_Set: in structured induction proofs, the insert case
  1744 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1745 (insert F x)'.
  1746 
  1747 * The 'refute' command has been extended to support a much larger
  1748 fragment of HOL, including axiomatic type classes, constdefs and
  1749 typedefs, inductive datatypes and recursion.
  1750 
  1751 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1752 Requires zChaff with proof generation to be installed.  See
  1753 HOL/ex/SAT_Examples.thy for examples.
  1754 
  1755 * Datatype induction via method 'induct' now preserves the name of the
  1756 induction variable. For example, when proving P(xs::'a list) by
  1757 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1758 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1759 in unstructured proof scripts.
  1760 
  1761 * Reworked implementation of records.  Improved scalability for
  1762 records with many fields, avoiding performance problems for type
  1763 inference. Records are no longer composed of nested field types, but
  1764 of nested extension types. Therefore the record type only grows linear
  1765 in the number of extensions and not in the number of fields.  The
  1766 top-level (users) view on records is preserved.  Potential
  1767 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1768 old record representation. The type generated for a record is called
  1769 <record_name>_ext_type.
  1770 
  1771 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1772 proofs triggered by a record definition or a simproc (if
  1773 quick_and_dirty is enabled).  Definitions of large records can take
  1774 quite long.
  1775 
  1776 New simproc record_upd_simproc for simplification of multiple record
  1777 updates enabled by default.  Moreover, trivial updates are also
  1778 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1779 occasionally, since simplification is more powerful by default.
  1780 
  1781 * typedef: proper support for polymorphic sets, which contain extra
  1782 type-variables in the term.
  1783 
  1784 * Simplifier: automatically reasons about transitivity chains
  1785 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1786 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1787 old proofs break occasionally as simplification may now solve more
  1788 goals than previously.
  1789 
  1790 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1791 present.  Works for all partial orders (class "order"), in particular
  1792 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1793 just like y <= x.
  1794 
  1795 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1796 bound variable or a constant then the let is unfolded.  Otherwise
  1797 first a is simplified to b, and then f b is simplified to g. If
  1798 possible we abstract b from g arriving at "let x = b in h x",
  1799 otherwise we unfold the let and arrive at g.  The simproc can be
  1800 enabled/disabled by the reference use_let_simproc.  Potential
  1801 INCOMPATIBILITY since simplification is more powerful by default.
  1802 
  1803 * Classical reasoning: the meson method now accepts theorems as arguments.
  1804 
  1805 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1806 jobs to provide advice on the provability of subgoals.
  1807 
  1808 * Theory OrderedGroup and Ring_and_Field: various additions and
  1809 improvements to faciliate calculations involving equalities and
  1810 inequalities.
  1811 
  1812 The following theorems have been eliminated or modified
  1813 (INCOMPATIBILITY):
  1814 
  1815   abs_eq             now named abs_of_nonneg
  1816   abs_of_ge_0        now named abs_of_nonneg
  1817   abs_minus_eq       now named abs_of_nonpos
  1818   imp_abs_id         now named abs_of_nonneg
  1819   imp_abs_neg_id     now named abs_of_nonpos
  1820   mult_pos           now named mult_pos_pos
  1821   mult_pos_le        now named mult_nonneg_nonneg
  1822   mult_pos_neg_le    now named mult_nonneg_nonpos
  1823   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1824   mult_neg           now named mult_neg_neg
  1825   mult_neg_le        now named mult_nonpos_nonpos
  1826 
  1827 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1828      
  1829      zero_le_square
  1830      not_square_less_zero 
  1831 
  1832   The following lemmas have been deleted from Real/RealPow:
  1833   
  1834      realpow_zero_zero
  1835      realpow_two
  1836      realpow_less
  1837      zero_le_power
  1838      realpow_two_le
  1839      abs_realpow_two
  1840      realpow_two_abs     
  1841 
  1842 * Theory Parity: added rules for simplifying exponents.
  1843 
  1844 * Theory List:
  1845 
  1846 The following theorems have been eliminated or modified
  1847 (INCOMPATIBILITY):
  1848 
  1849   list_all_Nil       now named list_all.simps(1)
  1850   list_all_Cons      now named list_all.simps(2)
  1851   list_all_conv      now named list_all_iff
  1852   set_mem_eq         now named mem_iff
  1853 
  1854 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1855 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1856 
  1857 
  1858 *** HOL-Complex ***
  1859 
  1860 * Theory RealDef: better support for embedding natural numbers and
  1861 integers in the reals.
  1862 
  1863 The following theorems have been eliminated or modified
  1864 (INCOMPATIBILITY):
  1865 
  1866   exp_ge_add_one_self  now requires no hypotheses
  1867   real_of_int_add      reversed direction of equality (use [symmetric])
  1868   real_of_int_minus    reversed direction of equality (use [symmetric])
  1869   real_of_int_diff     reversed direction of equality (use [symmetric])
  1870   real_of_int_mult     reversed direction of equality (use [symmetric])
  1871 
  1872 * Theory RComplete: expanded support for floor and ceiling functions.
  1873 
  1874 * Theory Ln is new, with properties of the natural logarithm
  1875 
  1876 * Hyperreal: There is a new type constructor "star" for making
  1877 nonstandard types.  The old type names are now type synonyms:
  1878 
  1879   hypreal = real star
  1880   hypnat = nat star
  1881   hcomplex = complex star
  1882 
  1883 * Hyperreal: Many groups of similarly-defined constants have been
  1884 replaced by polymorphic versions (INCOMPATIBILITY):
  1885 
  1886   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1887 
  1888   starset      <-- starsetNat, starsetC
  1889   *s*          <-- *sNat*, *sc*
  1890   starset_n    <-- starsetNat_n, starsetC_n
  1891   *sn*         <-- *sNatn*, *scn*
  1892   InternalSets <-- InternalNatSets, InternalCSets
  1893 
  1894   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1895   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1896   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1897   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1898   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1899 
  1900 * Hyperreal: Many type-specific theorems have been removed in favor of
  1901 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1902 
  1903   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1904   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1905   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1906   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1907   right_minus <-- hypreal_add_minus
  1908   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1909   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1910   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1911   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1912   mult_1_right <-- hcomplex_mult_one_right
  1913   mult_zero_left <-- hcomplex_mult_zero_left
  1914   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1915   right_distrib <-- hypnat_add_mult_distrib2
  1916   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1917   right_inverse <-- hypreal_mult_inverse
  1918   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1919   order_refl <-- {hypreal,hypnat}_le_refl
  1920   order_trans <-- {hypreal,hypnat}_le_trans
  1921   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1922   order_less_le <-- {hypreal,hypnat}_less_le
  1923   linorder_linear <-- {hypreal,hypnat}_le_linear
  1924   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1925   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1926   add_nonneg_nonneg <-- hypreal_le_add_order
  1927 
  1928 * Hyperreal: Separate theorems having to do with type-specific
  1929 versions of constants have been merged into theorems that apply to the
  1930 new polymorphic constants (INCOMPATIBILITY):
  1931 
  1932   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1933   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1934   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1935   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1936   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1937   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1938   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1939   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1940   STAR_diff <-- {STAR,STARC}_diff
  1941   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1942     STARC_hcomplex_of_complex}_image_subset
  1943   starset_n_Un <-- starset{Nat,C}_n_Un
  1944   starset_n_Int <-- starset{Nat,C}_n_Int
  1945   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1946   starset_n_diff <-- starset{Nat,C}_n_diff
  1947   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1948   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1949   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1950   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1951   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1952   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1953   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1954   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1955   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1956   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1957   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1958   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1959   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1960   starfun_diff <-- starfun{C,RC,CR}_diff
  1961   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1962   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1963   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1964   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1965   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1966   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1967   starfun_Id <-- starfunC_Id
  1968   starfun_approx <-- starfun{Nat,CR}_approx
  1969   starfun_capprox <-- starfun{C,RC}_capprox
  1970   starfun_abs <-- starfunNat_rabs
  1971   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1972   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1973   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1974   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1975   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1976   starfun_add_approx <-- starfunCR_add_approx
  1977   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1978   starfun_divide <-- starfun{C,CR,RC}_divide
  1979   starfun_n <-- starfun{Nat,C}_n
  1980   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1981   starfun_n_add <-- starfun{Nat,C}_n_add
  1982   starfun_n_add_minus <-- starfunNat_n_add_minus
  1983   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1984   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1985   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1986 
  1987   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1988   star_n_minus <-- {hypreal,hcomplex}_minus
  1989   star_n_diff <-- {hypreal,hcomplex}_diff
  1990   star_n_mult <-- {hypreal,hcomplex}_mult
  1991   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1992   star_n_le <-- {hypreal,hypnat}_le
  1993   star_n_less <-- {hypreal,hypnat}_less
  1994   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1995   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1996   star_n_abs <-- hypreal_hrabs
  1997   star_n_divide <-- hcomplex_divide
  1998 
  1999   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2000   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2001   star_of_diff <-- hypreal_of_real_diff
  2002   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2003   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2004   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2005   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2006   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2007   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2008   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2009   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2010   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2011   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2012   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2013   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2014   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2015   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2016   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2017   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2018   star_of_power <-- hypreal_of_real_power
  2019   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2020 
  2021 * Hyperreal: new method "transfer" that implements the transfer
  2022 principle of nonstandard analysis. With a subgoal that mentions
  2023 nonstandard types like "'a star", the command "apply transfer"
  2024 replaces it with an equivalent one that mentions only standard types.
  2025 To be successful, all free variables must have standard types; non-
  2026 standard variables must have explicit universal quantifiers.
  2027 
  2028 * Hyperreal: A theory of Taylor series.
  2029 
  2030 
  2031 *** HOLCF ***
  2032 
  2033 * Discontinued special version of 'constdefs' (which used to support
  2034 continuous functions) in favor of the general Pure one with full
  2035 type-inference.
  2036 
  2037 * New simplification procedure for solving continuity conditions; it
  2038 is much faster on terms with many nested lambda abstractions (cubic
  2039 instead of exponential time).
  2040 
  2041 * New syntax for domain package: selector names are now optional.
  2042 Parentheses should be omitted unless argument is lazy, for example:
  2043 
  2044   domain 'a stream = cons "'a" (lazy "'a stream")
  2045 
  2046 * New command 'fixrec' for defining recursive functions with pattern
  2047 matching; defining multiple functions with mutual recursion is also
  2048 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2049 sinr, or any data constructor defined by the domain package. The given
  2050 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2051 syntax and examples.
  2052 
  2053 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2054 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2055 but the proof obligation additionally includes an admissibility
  2056 requirement. The packages generate instances of class cpo or pcpo,
  2057 with continuity and strictness theorems for Rep and Abs.
  2058 
  2059 * HOLCF: Many theorems have been renamed according to a more standard naming
  2060 scheme (INCOMPATIBILITY):
  2061 
  2062   foo_inject:  "foo$x = foo$y ==> x = y"
  2063   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2064   foo_less:    "(foo$x << foo$y) = (x << y)"
  2065   foo_strict:  "foo$UU = UU"
  2066   foo_defined: "... ==> foo$x ~= UU"
  2067   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2068 
  2069 
  2070 *** ZF ***
  2071 
  2072 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2073 including the First Isomorphism Theorem (on quotienting by the kernel
  2074 of a homomorphism).
  2075 
  2076 * ZF/Simplifier: install second copy of type solver that actually
  2077 makes use of TC rules declared to Isar proof contexts (or locales);
  2078 the old version is still required for ML proof scripts.
  2079 
  2080 
  2081 *** Cube ***
  2082 
  2083 * Converted to Isar theory format; use locales instead of axiomatic
  2084 theories.
  2085 
  2086 
  2087 *** ML ***
  2088 
  2089 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2090 for ||>, ||>>, |>>,
  2091 
  2092 * Pure/library.ML no longer defines its own option datatype, but uses
  2093 that of the SML basis, which has constructors NONE and SOME instead of
  2094 None and Some, as well as exception Option.Option instead of OPTION.
  2095 The functions the, if_none, is_some, is_none have been adapted
  2096 accordingly, while Option.map replaces apsome.
  2097 
  2098 * Pure/library.ML: the exception LIST has been given up in favour of
  2099 the standard exceptions Empty and Subscript, as well as
  2100 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2101 superceded by the standard hd and tl functions etc.
  2102 
  2103 A number of basic list functions are no longer exported to the ML
  2104 toplevel, as they are variants of predefined functions.  The following
  2105 suggests how one can translate existing code:
  2106 
  2107     rev_append xs ys = List.revAppend (xs, ys)
  2108     nth_elem (i, xs) = List.nth (xs, i)
  2109     last_elem xs = List.last xs
  2110     flat xss = List.concat xss
  2111     seq fs = List.app fs
  2112     partition P xs = List.partition P xs
  2113     mapfilter f xs = List.mapPartial f xs
  2114 
  2115 * Pure/library.ML: several combinators for linear functional
  2116 transformations, notably reverse application and composition:
  2117 
  2118   x |> f                f #> g
  2119   (x, y) |-> f          f #-> g
  2120 
  2121 * Pure/library.ML: introduced/changed precedence of infix operators:
  2122 
  2123   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2124   infix 2 ?;
  2125   infix 3 o oo ooo oooo;
  2126   infix 4 ~~ upto downto;
  2127 
  2128 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2129 infix operators.
  2130 
  2131 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2132 fold_map support linear functional transformations and nesting.  For
  2133 example:
  2134 
  2135   fold f [x1, ..., xN] y =
  2136     y |> f x1 |> ... |> f xN
  2137 
  2138   (fold o fold) f [xs1, ..., xsN] y =
  2139     y |> fold f xs1 |> ... |> fold f xsN
  2140 
  2141   fold f [x1, ..., xN] =
  2142     f x1 #> ... #> f xN
  2143 
  2144   (fold o fold) f [xs1, ..., xsN] =
  2145     fold f xs1 #> ... #> fold f xsN
  2146 
  2147 * Pure/library.ML: the following selectors on type 'a option are
  2148 available:
  2149 
  2150   the:               'a option -> 'a  (*partial*)
  2151   these:             'a option -> 'a  where 'a = 'b list
  2152   the_default: 'a -> 'a option -> 'a
  2153   the_list:          'a option -> 'a list
  2154 
  2155 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2156 basic operations for association lists, following natural argument
  2157 order; moreover the explicit equality predicate passed here avoids
  2158 potentially expensive polymorphic runtime equality checks.
  2159 The old functions may be expressed as follows:
  2160 
  2161   assoc = uncurry (AList.lookup (op =))
  2162   assocs = these oo AList.lookup (op =)
  2163   overwrite = uncurry (AList.update (op =)) o swap
  2164 
  2165 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2166 
  2167   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2168   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2169 
  2170 replacing make_keylist and keyfilter (occassionally used)
  2171 Naive rewrites:
  2172 
  2173   make_keylist = AList.make
  2174   keyfilter = AList.find (op =)
  2175 
  2176 * eq_fst and eq_snd now take explicit equality parameter, thus
  2177   avoiding eqtypes. Naive rewrites:
  2178 
  2179     eq_fst = eq_fst (op =)
  2180     eq_snd = eq_snd (op =)
  2181 
  2182 * Removed deprecated apl and apr (rarely used).
  2183   Naive rewrites:
  2184 
  2185     apl (n, op) =>>= curry op n
  2186     apr (op, m) =>>= fn n => op (n, m)
  2187 
  2188 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2189 provides a reasonably efficient light-weight implementation of sets as
  2190 lists.
  2191 
  2192 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2193 few new operations; existing lookup and update are now curried to
  2194 follow natural argument order (for use with fold etc.);
  2195 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2196 
  2197 * Pure/General: output via the Isabelle channels of
  2198 writeln/warning/error etc. is now passed through Output.output, with a
  2199 hook for arbitrary transformations depending on the print_mode
  2200 (cf. Output.add_mode -- the first active mode that provides a output
  2201 function wins).  Already formatted output may be embedded into further
  2202 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2203 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2204 accommodate easy composition of diagnostic messages etc.  Programmers
  2205 rarely need to care about Output.output or Output.raw at all, with
  2206 some notable exceptions: Output.output is required when bypassing the
  2207 standard channels (writeln etc.), or in token translations to produce
  2208 properly formatted results; Output.raw is required when capturing
  2209 already output material that will eventually be presented to the user
  2210 a second time.  For the default print mode, both Output.output and
  2211 Output.raw have no effect.
  2212 
  2213 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2214 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2215 cumulative results are displayed at the end of a batch session.
  2216 
  2217 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2218 replaced by File.platform_path and File.shell_path (with appropriate
  2219 hooks).  This provides a clean interface for unusual systems where the
  2220 internal and external process view of file names are different.
  2221 
  2222 * Pure: more efficient orders for basic syntactic entities: added
  2223 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2224 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2225 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2226 orders now -- potential INCOMPATIBILITY for code that depends on a
  2227 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2228 Library.sort_strings on result).
  2229 
  2230 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2231 fold_types traverse types/terms from left to right, observing natural
  2232 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2233 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2234 
  2235 * Pure: name spaces have been refined, with significant changes of the
  2236 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2237 to extern(_table).  The plain name entry path is superceded by a
  2238 general 'naming' context, which also includes the 'policy' to produce
  2239 a fully qualified name and external accesses of a fully qualified
  2240 name; NameSpace.extend is superceded by context dependent
  2241 Sign.declare_name.  Several theory and proof context operations modify
  2242 the naming context.  Especially note Theory.restore_naming and
  2243 ProofContext.restore_naming to get back to a sane state; note that
  2244 Theory.add_path is no longer sufficient to recover from
  2245 Theory.absolute_path in particular.
  2246 
  2247 * Pure: new flags short_names (default false) and unique_names
  2248 (default true) for controlling output of qualified names.  If
  2249 short_names is set, names are printed unqualified.  If unique_names is
  2250 reset, the name prefix is reduced to the minimum required to achieve
  2251 the original result when interning again, even if there is an overlap
  2252 with earlier declarations.
  2253 
  2254 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2255 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2256 (useful for printing error messages).  INCOMPATIBILITY.
  2257 
  2258 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2259 Theory.theory are now identified, referring to the universal
  2260 Context.theory (see Pure/context.ML).  Actual signature and theory
  2261 content is managed as theory data.  The old code and interfaces were
  2262 spread over many files and structures; the new arrangement introduces
  2263 considerable INCOMPATIBILITY to gain more clarity:
  2264 
  2265   Context -- theory management operations (name, identity, inclusion,
  2266     parents, ancestors, merge, etc.), plus generic theory data;
  2267 
  2268   Sign -- logical signature and syntax operations (declaring consts,
  2269     types, etc.), plus certify/read for common entities;
  2270 
  2271   Theory -- logical theory operations (stating axioms, definitions,
  2272     oracles), plus a copy of logical signature operations (consts,
  2273     types, etc.); also a few basic management operations (Theory.copy,
  2274     Theory.merge, etc.)
  2275 
  2276 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2277 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2278 for convenience -- they merely return the theory.
  2279 
  2280 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2281 
  2282 * Pure: the Isar proof context type is already defined early in Pure
  2283 as Context.proof (note that ProofContext.context and Proof.context are
  2284 aliases, where the latter is the preferred name).  This enables other
  2285 Isabelle components to refer to that type even before Isar is present.
  2286 
  2287 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2288 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2289 any of these kinds.  For example, Sign.intern typeK is now
  2290 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2291 Theory.hide_types.  Also note that former
  2292 Theory.hide_classes/types/consts are now
  2293 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2294 internalize their arguments!  INCOMPATIBILITY.
  2295 
  2296 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2297 datatype thmref (with constructors Name and NameSelection) instead of
  2298 plain string -- INCOMPATIBILITY;
  2299 
  2300 * Pure: cases produced by proof methods specify options, where NONE
  2301 means to remove case bindings -- INCOMPATIBILITY in
  2302 (RAW_)METHOD_CASES.
  2303 
  2304 * Pure: the following operations retrieve axioms or theorems from a
  2305 theory node or theory hierarchy, respectively:
  2306 
  2307   Theory.axioms_of: theory -> (string * term) list
  2308   Theory.all_axioms_of: theory -> (string * term) list
  2309   PureThy.thms_of: theory -> (string * thm) list
  2310   PureThy.all_thms_of: theory -> (string * thm) list
  2311 
  2312 * Pure: print_tac now outputs the goal through the trace channel.
  2313 
  2314 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2315 Reference Toplevel.debug (default false) controls detailed printing
  2316 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2317 controls execution profiling -- set to 1 for time and 2 for space
  2318 (both increase the runtime).
  2319 
  2320 * Isar session: The initial use of ROOT.ML is now always timed,
  2321 i.e. the log will show the actual process times, in contrast to the
  2322 elapsed wall-clock time that the outer shell wrapper produces.
  2323 
  2324 * Simplifier: improved handling of bound variables (nameless
  2325 representation, avoid allocating new strings).  Simprocs that invoke
  2326 the Simplifier recursively should use Simplifier.inherit_bounds to
  2327 avoid local name clashes.  Failure to do so produces warnings
  2328 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2329 for further details.
  2330 
  2331 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2332 bindings for all theorems stored within a given theory; this may help
  2333 in porting non-Isar theories to Isar ones, while keeping ML proof
  2334 scripts for the time being.
  2335 
  2336 * ML operator HTML.with_charset specifies the charset begin used for
  2337 generated HTML files.  For example:
  2338 
  2339   HTML.with_charset "utf-8" use_thy "Hebrew";
  2340   HTML.with_charset "utf-8" use_thy "Chinese";
  2341 
  2342 
  2343 *** System ***
  2344 
  2345 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2346 isabelle, isatool etc.).
  2347 
  2348 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2349 isatool doc, isatool mkdir, display_drafts etc.).
  2350 
  2351 * isatool usedir: option -f allows specification of the ML file to be
  2352 used by Isabelle; default is ROOT.ML.
  2353 
  2354 * New isatool version outputs the version identifier of the Isabelle
  2355 distribution being used.
  2356 
  2357 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2358 (containing Boolean satisfiability problems) into Isabelle/HOL
  2359 theories.
  2360 
  2361 
  2362 
  2363 New in Isabelle2004 (April 2004)
  2364 --------------------------------
  2365 
  2366 *** General ***
  2367 
  2368 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2369   Replaces linorder.ML.
  2370 
  2371 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2372   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2373   (\<a>...\<z>), are now considered normal letters, and can therefore
  2374   be used anywhere where an ASCII letter (a...zA...Z) has until
  2375   now. COMPATIBILITY: This obviously changes the parsing of some
  2376   terms, especially where a symbol has been used as a binder, say
  2377   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2378   as an identifier.  Fix it by inserting a space around former
  2379   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2380   existing theory and ML files.
  2381 
  2382 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2383 
  2384 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2385   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2386   a normal (but invisible) letter. For multiple letter subscripts repeat
  2387   \<^isub> like this: x\<^isub>1\<^isub>2.
  2388 
  2389 * Pure: There are now sub-/superscripts that can span more than one
  2390   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2391   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2392   superscript. The new control characters are not identifier parts.
  2393 
  2394 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2395   content of "..." to the latex file instead of \isacntrl... . The "..."
  2396   may consist of any printable characters excluding the end bracket >.
  2397 
  2398 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2399   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2400   declare constants "final", which prevents their being given a definition
  2401   later.  It is useful for constants whose behaviour is fixed axiomatically
  2402   rather than definitionally, such as the meta-logic connectives.
  2403 
  2404 * Pure: 'instance' now handles general arities with general sorts
  2405   (i.e. intersections of classes),
  2406 
  2407 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2408   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2409   It can be changed to alter the colors/layout of generated pages.
  2410 
  2411 
  2412 *** Isar ***
  2413 
  2414 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2415   cut_tac, subgoal_tac and thin_tac:
  2416   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2417     locales are no longer forced to write Isar proof scripts.
  2418     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2419     emulations.
  2420   - INCOMPATIBILITY: names of variables to be instantiated may no
  2421     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2422     This is consistent with the instantiation attribute "where".
  2423 
  2424 * Attributes "where" and "of":
  2425   - Now take type variables of instantiated theorem into account when reading
  2426     the instantiation string.  This fixes a bug that caused instantiated
  2427     theorems to have too special types in some circumstances.
  2428   - "where" permits explicit instantiations of type variables.
  2429 
  2430 * Calculation commands "moreover" and "also" no longer interfere with
  2431   current facts ("this"), admitting arbitrary combinations with "then"
  2432   and derived forms.
  2433 
  2434 * Locales:
  2435   - Goal statements involving the context element "includes" no longer
  2436     generate theorems with internal delta predicates (those ending on
  2437     "_axioms") in the premise.
  2438     Resolve particular premise with <locale>.intro to obtain old form.
  2439   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2440     specification and "includes" elements in goal statement.
  2441   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2442     [intro?] and [elim?] (respectively) by default.
  2443   - Experimental command for instantiation of locales in proof contexts:
  2444         instantiate <label>[<attrs>]: <loc>
  2445     Instantiates locale <loc> and adds all its theorems to the current context
  2446     taking into account their attributes.  Label and attrs are optional
  2447     modifiers, like in theorem declarations.  If present, names of
  2448     instantiated theorems are qualified with <label>, and the attributes
  2449     <attrs> are applied after any attributes these theorems might have already.
  2450       If the locale has assumptions, a chained fact of the form
  2451     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2452     are derived.  The command does not support old-style locales declared
  2453     with "locale (open)".
  2454       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2455 
  2456 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2457   (Isar) contexts.
  2458 
  2459 
  2460 *** HOL ***
  2461 
  2462 * Proof import: new image HOL4 contains the imported library from
  2463   the HOL4 system with about 2500 theorems. It is imported by
  2464   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2465   can be used like any other Isabelle image.  See
  2466   HOL/Import/HOL/README for more information.
  2467 
  2468 * Simplifier:
  2469   - Much improved handling of linear and partial orders.
  2470     Reasoners for linear and partial orders are set up for type classes
  2471     "linorder" and "order" respectively, and are added to the default simpset
  2472     as solvers.  This means that the simplifier can build transitivity chains
  2473     to solve goals from the assumptions.
  2474   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2475     of blast or auto after simplification become unnecessary because the goal
  2476     is solved by simplification already.
  2477 
  2478 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2479     all proved in axiomatic type classes for semirings, rings and fields.
  2480 
  2481 * Numerics:
  2482   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2483     now formalized using the Ring_and_Field theory mentioned above.
  2484   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2485     than before, because now they are set up once in a generic manner.
  2486   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2487     Look for the general versions in Ring_and_Field (and Power if they concern
  2488     exponentiation).
  2489 
  2490 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2491 
  2492 * Records:
  2493   - Record types are now by default printed with their type abbreviation
  2494     instead of the list of all field types. This can be configured via
  2495     the reference "print_record_type_abbr".
  2496   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2497     (not enabled by default).
  2498   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2499     EX x. x = sel r to True (not enabled by default).
  2500   - Tactic "record_split_simp_tac" to split and simplify records added.
  2501 
  2502 * 'specification' command added, allowing for definition by
  2503   specification.  There is also an 'ax_specification' command that
  2504   introduces the new constants axiomatically.
  2505 
  2506 * arith(_tac) is now able to generate counterexamples for reals as well.
  2507 
  2508 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2509 
  2510 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2511   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2512 
  2513 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2514   matrix theory to linear programming.
  2515 
  2516 * Unions and Intersections:
  2517   The latex output syntax of UN and INT has been changed
  2518   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2519   i.e. the index formulae has become a subscript.
  2520   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2521 
  2522 * Unions and Intersections over Intervals:
  2523   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2524   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2525   like in normal math, and corresponding versions for < and for intersection.
  2526 
  2527 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2528   lexicographic dictonary ordering has been added as "lexord".
  2529 
  2530 * ML: the legacy theory structures Int and List have been removed. They had
  2531   conflicted with ML Basis Library structures having the same names.
  2532 
  2533 * 'refute' command added to search for (finite) countermodels.  Only works
  2534   for a fragment of HOL.  The installation of an external SAT solver is
  2535   highly recommended.  See "HOL/Refute.thy" for details.
  2536 
  2537 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2538   formulae under an assignment of free variables to random values.
  2539   In contrast to 'refute', it can deal with inductive datatypes,
  2540   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2541   for examples.
  2542 
  2543 
  2544 *** HOLCF ***
  2545 
  2546 * Streams now come with concatenation and are part of the HOLCF image
  2547 
  2548 
  2549 
  2550 New in Isabelle2003 (May 2003)
  2551 ------------------------------
  2552 
  2553 *** General ***
  2554 
  2555 * Provers/simplifier:
  2556 
  2557   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2558     Assumptions are now subject to complete mutual simplification,
  2559     not just from left to right. The simplifier now preserves
  2560     the order of assumptions.
  2561 
  2562     Potential INCOMPATIBILITY:
  2563 
  2564     -- simp sometimes diverges where the old version did
  2565        not, e.g. invoking simp on the goal
  2566 
  2567         [| P (f x); y = x; f x = f y |] ==> Q
  2568 
  2569        now gives rise to the infinite reduction sequence
  2570 
  2571         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2572 
  2573        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2574        kind of problem.
  2575 
  2576     -- Tactics combining classical reasoner and simplification (such as auto)
  2577        are also affected by this change, because many of them rely on
  2578        simp. They may sometimes diverge as well or yield a different numbers
  2579        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2580        in case of problems. Sometimes subsequent calls to the classical
  2581        reasoner will fail because a preceeding call to the simplifier too
  2582        eagerly simplified the goal, e.g. deleted redundant premises.
  2583 
  2584   - The simplifier trace now shows the names of the applied rewrite rules
  2585 
  2586   - You can limit the number of recursive invocations of the simplifier
  2587     during conditional rewriting (where the simplifie tries to solve the
  2588     conditions before applying the rewrite rule):
  2589     ML "simp_depth_limit := n"
  2590     where n is an integer. Thus you can force termination where previously
  2591     the simplifier would diverge.
  2592 
  2593   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2594 
  2595   - No longer aborts on failed congruence proof.  Instead, the
  2596     congruence is ignored.
  2597 
  2598 * Pure: New generic framework for extracting programs from constructive
  2599   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2600   as HOL/Extraction for some case studies.
  2601 
  2602 * Pure: The main goal of the proof state is no longer shown by default, only
  2603 the subgoals. This behaviour is controlled by a new flag.
  2604    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2605 (ML: Proof.show_main_goal).
  2606 
  2607 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2608 rules whose conclusion matches subgoal 1:
  2609       PG menu: Isabelle/Isar -> Show me -> matching rules
  2610 The rules are ordered by how closely they match the subgoal.
  2611 In particular, rules that solve a subgoal outright are displayed first
  2612 (or rather last, the way they are printed).
  2613 (ML: ProofGeneral.print_intros())
  2614 
  2615 * Pure: New flag trace_unify_fail causes unification to print
  2616 diagnostic information (PG: in trace buffer) when it fails. This is
  2617 useful for figuring out why single step proofs like rule, erule or
  2618 assumption failed.
  2619 
  2620 * Pure: Locale specifications now produce predicate definitions
  2621 according to the body of text (covering assumptions modulo local
  2622 definitions); predicate "loc_axioms" covers newly introduced text,
  2623 while "loc" is cumulative wrt. all included locale expressions; the
  2624 latter view is presented only on export into the global theory
  2625 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2626 on the old view without predicates;
  2627 
  2628 * Pure: predefined locales "var" and "struct" are useful for sharing
  2629 parameters (as in CASL, for example); just specify something like
  2630 ``var x + var y + struct M'' as import;
  2631 
  2632 * Pure: improved thms_containing: proper indexing of facts instead of
  2633 raw theorems; check validity of results wrt. current name space;
  2634 include local facts of proof configuration (also covers active
  2635 locales), cover fixed variables in index; may use "_" in term
  2636 specification; an optional limit for the number of printed facts may
  2637 be given (the default is 40);
  2638 
  2639 * Pure: disallow duplicate fact bindings within new-style theory files
  2640 (batch-mode only);
  2641 
  2642 * Provers: improved induct method: assumptions introduced by case
  2643 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2644 the goal statement); "foo" still refers to all facts collectively;
  2645 
  2646 * Provers: the function blast.overloaded has been removed: all constants
  2647 are regarded as potentially overloaded, which improves robustness in exchange
  2648 for slight decrease in efficiency;
  2649 
  2650 * Provers/linorder: New generic prover for transitivity reasoning over
  2651 linear orders.  Note: this prover is not efficient!
  2652 
  2653 * Isar: preview of problems to finish 'show' now produce an error
  2654 rather than just a warning (in interactive mode);
  2655 
  2656 
  2657 *** HOL ***
  2658 
  2659 * arith(_tac)
  2660 
  2661  - Produces a counter example if it cannot prove a goal.
  2662    Note that the counter example may be spurious if the goal is not a formula
  2663    of quantifier-free linear arithmetic.
  2664    In ProofGeneral the counter example appears in the trace buffer.
  2665 
  2666  - Knows about div k and mod k where k is a numeral of type nat or int.
  2667 
  2668  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2669    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2670    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2671 
  2672 * simp's arithmetic capabilities have been enhanced a bit: it now
  2673 takes ~= in premises into account (by performing a case split);
  2674 
  2675 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2676 are distributed over a sum of terms;
  2677 
  2678 * New tactic "trans_tac" and method "trans" instantiate
  2679 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2680 "<=", "<" and "=").
  2681 
  2682 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2683 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2684 
  2685 * 'typedef' command has new option "open" to suppress the set
  2686 definition;
  2687 
  2688 * functions Min and Max on finite sets have been introduced (theory
  2689 Finite_Set);
  2690 
  2691 * attribute [symmetric] now works for relations as well; it turns
  2692 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2693 
  2694 * induct over a !!-quantified statement (say !!x1..xn):
  2695   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2696 
  2697 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2698 %x. None. Warning: empty_def now refers to the previously hidden definition
  2699 of the empty set.
  2700 
  2701 * Algebra: formalization of classical algebra.  Intended as base for
  2702 any algebraic development in Isabelle.  Currently covers group theory
  2703 (up to Sylow's theorem) and ring theory (Universal Property of
  2704 Univariate Polynomials).  Contributions welcome;
  2705 
  2706 * GroupTheory: deleted, since its material has been moved to Algebra;
  2707 
  2708 * Complex: new directory of the complex numbers with numeric constants,
  2709 nonstandard complex numbers, and some complex analysis, standard and
  2710 nonstandard (Jacques Fleuriot);
  2711 
  2712 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2713 
  2714 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2715 Fleuriot);
  2716 
  2717 * Real/HahnBanach: updated and adapted to locales;
  2718 
  2719 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2720 Gray and Kramer);
  2721 
  2722 * UNITY: added the Meier-Sanders theory of progress sets;
  2723 
  2724 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2725 as abstract algorithms, instantiated to the JVM;
  2726 
  2727 * Bali: Java source language formalization. Type system, operational
  2728 semantics, axiomatic semantics. Supported language features:
  2729 classes, interfaces, objects,virtual methods, static methods,
  2730 static/instance fields, arrays, access modifiers, definite
  2731 assignment, exceptions.
  2732 
  2733 
  2734 *** ZF ***
  2735 
  2736 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2737 universe, etc.);
  2738 
  2739 * Main ZF: virtually all theories converted to new-style format;
  2740 
  2741 
  2742 *** ML ***
  2743 
  2744 * Pure: Tactic.prove provides sane interface for internal proofs;
  2745 omits the infamous "standard" operation, so this is more appropriate
  2746 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2747 
  2748 * Pure: improved error reporting of simprocs;
  2749 
  2750 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2751 up simprocs;
  2752 
  2753 
  2754 *** Document preparation ***
  2755 
  2756 * uses \par instead of \\ for line breaks in theory text. This may
  2757 shift some page breaks in large documents. To get the old behaviour
  2758 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2759 
  2760 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2761 other packages
  2762 
  2763 * \<euro> now needs package babel/greek instead of marvosym (which
  2764 broke \Rightarrow)
  2765 
  2766 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2767 textcomp package)
  2768 
  2769 
  2770 
  2771 New in Isabelle2002 (March 2002)
  2772 --------------------------------
  2773 
  2774 *** Document preparation ***
  2775 
  2776 * greatly simplified document preparation setup, including more
  2777 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2778 instructive isatool mkdir; users should basically be able to get
  2779 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2780 users may run a separate document processing stage manually like this:
  2781 "isatool usedir -D output HOL Test && isatool document Test/output";
  2782 
  2783 * theory dependency graph may now be incorporated into documents;
  2784 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2785 with \includegraphics of LaTeX;
  2786 
  2787 * proper spacing of consecutive markup elements, especially text
  2788 blocks after section headings;
  2789 
  2790 * support bold style (for single symbols only), input syntax is like
  2791 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2792 
  2793 * \<bullet> is now output as bold \cdot by default, which looks much
  2794 better in printed text;
  2795 
  2796 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2797 note that these symbols are currently unavailable in Proof General /
  2798 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2799 
  2800 * isatool latex no longer depends on changed TEXINPUTS, instead
  2801 isatool document copies the Isabelle style files to the target
  2802 location;
  2803 
  2804 
  2805 *** Isar ***
  2806 
  2807 * Pure/Provers: improved proof by cases and induction;
  2808   - 'case' command admits impromptu naming of parameters (such as
  2809     "case (Suc n)");
  2810   - 'induct' method divinates rule instantiation from the inductive
  2811     claim; no longer requires excessive ?P bindings for proper
  2812     instantiation of cases;
  2813   - 'induct' method properly enumerates all possibilities of set/type
  2814     rules; as a consequence facts may be also passed through *type*
  2815     rules without further ado;
  2816   - 'induct' method now derives symbolic cases from the *rulified*
  2817     rule (before it used to rulify cases stemming from the internal
  2818     atomized version); this means that the context of a non-atomic
  2819     statement becomes is included in the hypothesis, avoiding the
  2820     slightly cumbersome show "PROP ?case" form;
  2821   - 'induct' may now use elim-style induction rules without chaining
  2822     facts, using ``missing'' premises from the goal state; this allows
  2823     rules stemming from inductive sets to be applied in unstructured
  2824     scripts, while still benefitting from proper handling of non-atomic
  2825     statements; NB: major inductive premises need to be put first, all
  2826     the rest of the goal is passed through the induction;
  2827   - 'induct' proper support for mutual induction involving non-atomic
  2828     rule statements (uses the new concept of simultaneous goals, see
  2829     below);
  2830   - append all possible rule selections, but only use the first
  2831     success (no backtracking);
  2832   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2833   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2834   - added 'print_induct_rules' (covered by help item in recent Proof
  2835     General versions);
  2836   - moved induct/cases attributes to Pure, methods to Provers;
  2837   - generic method setup instantiated for FOL and HOL;
  2838 
  2839 * Pure: support multiple simultaneous goal statements, for example
  2840 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2841 meta-level mechanism, this acts as if several individual goals had
  2842 been stated separately; in particular common proof methods need to be
  2843 repeated in order to cover all claims; note that a single elimination
  2844 step is *not* sufficient to establish the two conjunctions, so this
  2845 fails:
  2846 
  2847   assume "A & B" then have A and B ..   (*".." fails*)
  2848 
  2849 better use "obtain" in situations as above; alternative refer to
  2850 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2851 
  2852 * Pure: proper integration with ``locales''; unlike the original
  2853 version by Florian Kammller, Isar locales package high-level proof
  2854 contexts rather than raw logical ones (e.g. we admit to include
  2855 attributes everywhere); operations on locales include merge and
  2856 rename; support for implicit arguments (``structures''); simultaneous
  2857 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2858 some examples;
  2859 
  2860 * Pure: the following commands have been ``localized'', supporting a
  2861 target locale specification "(in name)": 'lemma', 'theorem',
  2862 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2863 stored both within the locale and at the theory level (exported and
  2864 qualified by the locale name);
  2865 
  2866 * Pure: theory goals may now be specified in ``long'' form, with
  2867 ad-hoc contexts consisting of arbitrary locale elements. for example
  2868 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2869 definitions may be given, too); the result is a meta-level rule with
  2870 the context elements being discharged in the obvious way;
  2871 
  2872 * Pure: new proof command 'using' allows to augment currently used
  2873 facts after a goal statement ('using' is syntactically analogous to
  2874 'apply', but acts on the goal's facts only); this allows chained facts
  2875 to be separated into parts given before and after a claim, as in
  2876 ``from a and b have C using d and e <proof>'';
  2877 
  2878 * Pure: renamed "antecedent" case to "rule_context";
  2879 
  2880 * Pure: new 'judgment' command records explicit information about the
  2881 object-logic embedding (used by several tools internally); no longer
  2882 use hard-wired "Trueprop";
  2883 
  2884 * Pure: added 'corollary' command;
  2885 
  2886 * Pure: fixed 'token_translation' command;
  2887 
  2888 * Pure: removed obsolete 'exported' attribute;
  2889 
  2890 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2891 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2892 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2893 
  2894 * Pure: method 'atomize' presents local goal premises as object-level
  2895 statements (atomic meta-level propositions); setup controlled via
  2896 rewrite rules declarations of 'atomize' attribute; example
  2897 application: 'induct' method with proper rule statements in improper
  2898 proof *scripts*;
  2899 
  2900 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2901 now consider the syntactic context of assumptions, giving a better
  2902 chance to get type-inference of the arguments right (this is
  2903 especially important for locales);
  2904 
  2905 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2906 mode;
  2907 
  2908 * Pure/obtain: the formal conclusion "thesis", being marked as
  2909 ``internal'', may no longer be reference directly in the text;
  2910 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2911 situations;
  2912 
  2913 * Pure: generic 'sym' attribute which declares a rule both as pure
  2914 'elim?' and for the 'symmetric' operation;
  2915 
  2916 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2917 text; the fixed correlation with particular command syntax has been
  2918 discontinued;
  2919 
  2920 * Pure: new method 'rules' is particularly well-suited for proof
  2921 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2922 but often produces more compact proof terms with less detours;
  2923 
  2924 * Pure/Provers/classical: simplified integration with pure rule
  2925 attributes and methods; the classical "intro?/elim?/dest?"
  2926 declarations coincide with the pure ones; the "rule" method no longer
  2927 includes classically swapped intros; "intro" and "elim" methods no
  2928 longer pick rules from the context; also got rid of ML declarations
  2929 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2930 INCOMPATIBILITY;
  2931 
  2932 * Provers/classical: attribute 'swapped' produces classical inversions
  2933 of introduction rules;
  2934 
  2935 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2936 rules instead of full simplifier context; 'iff' attribute handles
  2937 conditional rules;
  2938 
  2939 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2940 
  2941 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2942 "(permissive)" option to recover old behavior;
  2943 
  2944 * HOL: 'inductive' no longer features separate (collective) attributes
  2945 for 'intros' (was found too confusing);
  2946 
  2947 * HOL: properly declared induction rules less_induct and
  2948 wf_induct_rule;
  2949 
  2950 
  2951 *** HOL ***
  2952 
  2953 * HOL: moved over to sane numeral syntax; the new policy is as
  2954 follows:
  2955 
  2956   - 0 and 1 are polymorphic constants, which are defined on any
  2957   numeric type (nat, int, real etc.);
  2958 
  2959   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2960   binary representation internally;
  2961 
  2962   - type nat has special constructor Suc, and generally prefers Suc 0
  2963   over 1::nat and Suc (Suc 0) over 2::nat;
  2964 
  2965 This change may cause significant problems of INCOMPATIBILITY; here
  2966 are some hints on converting existing sources:
  2967 
  2968   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2969   entities, so expressions involving "-" (unary or binary minus) need
  2970   to be spaced properly;
  2971 
  2972   - existing occurrences of "1" may need to be constraint "1::nat" or
  2973   even replaced by Suc 0; similar for old "2";
  2974 
  2975   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2976 
  2977   - remove all special provisions on numerals in proofs;
  2978 
  2979 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2980 representation (depends on bin_arith_simps in the default context);
  2981 
  2982 * HOL: symbolic syntax for x^2 (numeral 2);
  2983 
  2984 * HOL: the class of all HOL types is now called "type" rather than
  2985 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2986 in axclass/classes, instance/arities, and (usually rare) occurrences
  2987 in typings (of consts etc.); internally the class is called
  2988 "HOL.type", ML programs should refer to HOLogic.typeS;
  2989 
  2990 * HOL/record package improvements:
  2991   - new derived operations "fields" to build a partial record section,
  2992     "extend" to promote a fixed record to a record scheme, and
  2993     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2994     declared as simp by default;
  2995   - shared operations ("more", "fields", etc.) now need to be always
  2996     qualified) --- potential INCOMPATIBILITY;
  2997   - removed "make_scheme" operations (use "make" with "extend") --
  2998     INCOMPATIBILITY;
  2999   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3000   - provides cases/induct rules for use with corresponding Isar
  3001     methods (for concrete records, record schemes, concrete more
  3002     parts, and schematic more parts -- in that order);
  3003   - internal definitions directly based on a light-weight abstract
  3004     theory of product types over typedef rather than datatype;
  3005 
  3006 * HOL: generic code generator for generating executable ML code from
  3007 specifications; specific support for HOL constructs such as inductive
  3008 datatypes and sets, as well as recursive functions; can be invoked
  3009 via 'generate_code' theory section;
  3010 
  3011 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3012 
  3013 * HOL: consolidated and renamed several theories.  In particular:
  3014         Ord.thy has been absorbed into HOL.thy
  3015         String.thy has been absorbed into List.thy
  3016 
  3017 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3018 (beware of argument permutation!);
  3019 
  3020 * HOL: linorder_less_split superseded by linorder_cases;
  3021 
  3022 * HOL/List: "nodups" renamed to "distinct";
  3023 
  3024 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3025 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3026   - Ex_def has changed, now need to use some_eq_ex
  3027 
  3028 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3029 in this (rare) case use:
  3030 
  3031   delSWrapper "split_all_tac"
  3032   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3033 
  3034 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3035 MAY FAIL;
  3036 
  3037 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3038 Isabelle's type classes, ^ on functions and relations has too general
  3039 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3040 necessary to attach explicit type constraints;
  3041 
  3042 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3043 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3044 renamed accordingly (eg "compI" -> "rel_compI").
  3045 
  3046 * HOL: syntax translations now work properly with numerals and records
  3047 expressions;
  3048 
  3049 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3050 of "lam" -- INCOMPATIBILITY;
  3051 
  3052 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3053 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3054 renamed "Product_Type.unit";
  3055 
  3056 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3057 
  3058 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3059 the "cases" method);
  3060 
  3061 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3062 Florian Kammller);
  3063 
  3064 * HOL/IMP: updated and converted to new-style theory format; several
  3065 parts turned into readable document, with proper Isar proof texts and
  3066 some explanations (by Gerwin Klein);
  3067 
  3068 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3069 
  3070 * HOL-Hyperreal is now a logic image;
  3071 
  3072 
  3073 *** HOLCF ***
  3074 
  3075 * Isar: consts/constdefs supports mixfix syntax for continuous
  3076 operations;
  3077 
  3078 * Isar: domain package adapted to new-style theory format, e.g. see
  3079 HOLCF/ex/Dnat.thy;
  3080 
  3081 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3082 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3083 lift.induct_tac, always use UU instead of Undef;
  3084 
  3085 * HOLCF/IMP: updated and converted to new-style theory;
  3086 
  3087 
  3088 *** ZF ***
  3089 
  3090 * Isar: proper integration of logic-specific tools and packages,
  3091 including theory commands '(co)inductive', '(co)datatype',
  3092 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3093 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3094 
  3095 * theory Main no longer includes AC; for the Axiom of Choice, base
  3096 your theory on Main_ZFC;
  3097 
  3098 * the integer library now covers quotients and remainders, with many
  3099 laws relating division to addition, multiplication, etc.;
  3100 
  3101 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3102 typeless version of the formalism;
  3103 
  3104 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3105 format;
  3106 
  3107 * ZF/Induct: new directory for examples of inductive definitions,
  3108 including theory Multiset for multiset orderings; converted to
  3109 new-style theory format;
  3110 
  3111 * ZF: many new theorems about lists, ordinals, etc.;
  3112 
  3113 
  3114 *** General ***
  3115 
  3116 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3117 variable proof controls level of detail: 0 = no proofs (only oracle
  3118 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3119 also ref manual for further ML interfaces;
  3120 
  3121 * Pure/axclass: removed obsolete ML interface
  3122 goal_subclass/goal_arity;
  3123 
  3124 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3125 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3126 separate tokens, so expressions involving minus need to be spaced
  3127 properly;
  3128 
  3129 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3130 rather than "infixl" or "infixr";
  3131 
  3132 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3133 sort constraint specifications in type inference; e.g. "x::_::foo"
  3134 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3135 type variable);
  3136 
  3137 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3138 control output of nested => (types); the default behavior is
  3139 "type_brackets";
  3140 
  3141 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3142 tokens into AST constants;
  3143 
  3144 * Pure/syntax: prefer later declarations of translations and print
  3145 translation functions; potential INCOMPATIBILITY: need to reverse
  3146 multiple declarations for same syntax element constant;
  3147 
  3148 * Pure/show_hyps reset by default (in accordance to existing Isar
  3149 practice);
  3150 
  3151 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3152 addSafter;
  3153 
  3154 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3155 as well;
  3156 
  3157 * system: tested support for MacOS X; should be able to get Isabelle +
  3158 Proof General to work in a plain Terminal after installing Poly/ML
  3159 (e.g. from the Isabelle distribution area) and GNU bash alone
  3160 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3161 support requires further installations, e.g. from
  3162 http://fink.sourceforge.net/);
  3163 
  3164 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3165 
  3166 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3167 of 40 MB), cf. ML_OPTIONS;
  3168 
  3169 * system: Proof General keywords specification is now part of the
  3170 Isabelle distribution (see etc/isar-keywords.el);
  3171 
  3172 * system: support for persistent Proof General sessions (refrain from
  3173 outdating all loaded theories on startup); user may create writable
  3174 logic images like this: ``isabelle -q HOL Test'';
  3175 
  3176 * system: smart selection of Isabelle process versus Isabelle
  3177 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3178 run both "isabelle" and "Isabelle" even if file names are badly
  3179 damaged (executable inspects the case of the first letter of its own
  3180 name); added separate "isabelle-process" and "isabelle-interface";
  3181 
  3182 * system: refrain from any attempt at filtering input streams; no
  3183 longer support ``8bit'' encoding of old isabelle font, instead proper
  3184 iso-latin characters may now be used; the related isatools
  3185 "symbolinput" and "nonascii" have disappeared as well;
  3186 
  3187 * system: removed old "xterm" interface (the print modes "xterm" and
  3188 "xterm_color" are still available for direct use in a suitable
  3189 terminal);
  3190 
  3191 
  3192 
  3193 New in Isabelle99-2 (February 2001)
  3194 -----------------------------------
  3195 
  3196 *** Overview of INCOMPATIBILITIES ***
  3197 
  3198 * HOL: please note that theories in the Library and elsewhere often use the
  3199 new-style (Isar) format; to refer to their theorems in an ML script you must
  3200 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3201 
  3202 * HOL: inductive package no longer splits induction rule aggressively,
  3203 but only as far as specified by the introductions given; the old
  3204 format may be recovered via ML function complete_split_rule or attribute
  3205 'split_rule (complete)';
  3206 
  3207 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3208 gfp_Tarski to gfp_unfold;
  3209 
  3210 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3211 
  3212 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3213 relation); infix "^^" has been renamed "``"; infix "``" has been
  3214 renamed "`"; "univalent" has been renamed "single_valued";
  3215 
  3216 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3217 operation;
  3218 
  3219 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3220 
  3221 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3222 
  3223 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3224 consequence, it is no longer monotonic wrt. the local goal context
  3225 (which is now passed through the inductive cases);
  3226 
  3227 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3228 \<gg> to \<ggreater>;
  3229 
  3230 
  3231 *** Document preparation ***
  3232 
  3233 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3234 available: are "it" for near math-mode best-style output, "sl" for
  3235 slanted text style, and "tt" for plain type-writer; if no
  3236 \isabellestyle command is given, output is according to slanted
  3237 type-writer);
  3238 
  3239 * support sub/super scripts (for single symbols only), input syntax is
  3240 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3241 
  3242 * some more standard symbols; see Appendix A of the system manual for
  3243 the complete list of symbols defined in isabellesym.sty;
  3244 
  3245 * improved isabelle style files; more abstract symbol implementation
  3246 (should now use \isamath{...} and \isatext{...} in custom symbol
  3247 definitions);
  3248 
  3249 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3250 state; Note that presentation of goal states does not conform to
  3251 actual human-readable proof documents.  Please do not include goal
  3252 states into document output unless you really know what you are doing!
  3253 
  3254 * proper indentation of antiquoted output with proportional LaTeX
  3255 fonts;
  3256 
  3257 * no_document ML operator temporarily disables LaTeX document
  3258 generation;
  3259 
  3260 * isatool unsymbolize tunes sources for plain ASCII communication;
  3261 
  3262 
  3263 *** Isar ***
  3264 
  3265 * Pure: Isar now suffers initial goal statements to contain unbound
  3266 schematic variables (this does not conform to actual readable proof
  3267 documents, due to unpredictable outcome and non-compositional proof
  3268 checking); users who know what they are doing may use schematic goals
  3269 for Prolog-style synthesis of proven results;
  3270 
  3271 * Pure: assumption method (an implicit finishing) now handles actual
  3272 rules as well;
  3273 
  3274 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3275 initial goal, declare "that" only as Pure intro (only for single
  3276 steps); the "that" rule assumption may now be involved in implicit
  3277 finishing, thus ".." becomes a feasible for trivial obtains;
  3278 
  3279 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3280 instance proofs may be performed by "..";
  3281 
  3282 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3283 statements as well;
  3284 
  3285 * Pure: more robust selection of calculational rules;
  3286 
  3287 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3288 rule (as well as the assumption rule);
  3289 
  3290 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3291 lemmas, using the graph browser tool;
  3292 
  3293 * Pure: predict failure of "show" in interactive mode;
  3294 
  3295 * Pure: 'thms_containing' now takes actual terms as arguments;
  3296 
  3297 * HOL: improved method 'induct' --- now handles non-atomic goals
  3298 (potential INCOMPATIBILITY); tuned error handling;
  3299 
  3300 * HOL: cases and induct rules now provide explicit hints about the
  3301 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3302 any remaining facts are inserted into the goal verbatim;
  3303 
  3304 * HOL: local contexts (aka cases) may now contain term bindings as
  3305 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3306 the result to be shown in each case;
  3307 
  3308 * HOL: added 'recdef_tc' command;
  3309 
  3310 * isatool convert assists in eliminating legacy ML scripts;
  3311 
  3312 
  3313 *** HOL ***
  3314 
  3315 * HOL/Library: a collection of generic theories to be used together
  3316 with main HOL; the theory loader path already includes this directory
  3317 by default; the following existing theories have been moved here:
  3318 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3319 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3320 
  3321 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3322 modelling and verification task performed in Isabelle/HOL +
  3323 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3324 
  3325 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3326 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3327 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3328 'domain', this makes the theory consistent with mathematical
  3329 literature;
  3330 
  3331 * HOL basics: added overloaded operations "inverse" and "divide"
  3332 (infix "/"), syntax for generic "abs" operation, generic summation
  3333 operator \<Sum>;
  3334 
  3335 * HOL/typedef: simplified package, provide more useful rules (see also
  3336 HOL/subset.thy);
  3337 
  3338 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3339 now expressed as a proper nested rule (old-style tactic scripts may
  3340 require atomize_strip_tac to cope with non-atomic premises);
  3341 
  3342 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3343 to "split_conv" (old name still available for compatibility);
  3344 
  3345 * HOL: improved concrete syntax for strings (e.g. allows translation
  3346 rules with string literals);
  3347 
  3348 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3349  and Fleuriot's mechanization of analysis, including the transcendental
  3350  functions for the reals;
  3351 
  3352 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3353 
  3354 
  3355 *** CTT ***
  3356 
  3357 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3358 "lam" is displayed as TWO lambda-symbols
  3359 
  3360 * CTT: theory Main now available, containing everything (that is, Bool
  3361 and Arith);
  3362 
  3363 
  3364 *** General ***
  3365 
  3366 * Pure: the Simplifier has been implemented properly as a derived rule
  3367 outside of the actual kernel (at last!); the overall performance
  3368 penalty in practical applications is about 50%, while reliability of
  3369 the Isabelle inference kernel has been greatly improved;
  3370 
  3371 * print modes "brackets" and "no_brackets" control output of nested =>
  3372 (types) and ==> (props); the default behaviour is "brackets";
  3373 
  3374 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3375 as assumptions as well;
  3376 
  3377 * system: support Poly/ML 4.0;
  3378 
  3379 * system: isatool install handles KDE version 1 or 2;
  3380 
  3381 
  3382 
  3383 New in Isabelle99-1 (October 2000)
  3384 ----------------------------------
  3385 
  3386 *** Overview of INCOMPATIBILITIES ***
  3387 
  3388 * HOL: simplification of natural numbers is much changed; to partly
  3389 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3390 issue the following ML commands:
  3391 
  3392   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3393   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3394 
  3395 * HOL: simplification no longer dives into case-expressions; this is
  3396 controlled by "t.weak_case_cong" for each datatype t;
  3397 
  3398 * HOL: nat_less_induct renamed to less_induct;
  3399 
  3400 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3401 fixsome to patch .thy and .ML sources automatically;
  3402 
  3403   select_equality  -> some_equality
  3404   select_eq_Ex     -> some_eq_ex
  3405   selectI2EX       -> someI2_ex
  3406   selectI2         -> someI2
  3407   selectI          -> someI
  3408   select1_equality -> some1_equality
  3409   Eps_sym_eq       -> some_sym_eq_trivial
  3410   Eps_eq           -> some_eq_trivial
  3411 
  3412 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3413 
  3414 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3415 instead);
  3416 
  3417 * HOL: the recursion equations generated by 'recdef' are now called
  3418 f.simps instead of f.rules;
  3419 
  3420 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3421 
  3422 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3423 sometimes be needed;
  3424 
  3425 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3426 
  3427 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3428 
  3429 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3430 product is now "<*>" instead of "Times"; the lexicographic product is
  3431 now "<*lex*>" instead of "**";
  3432 
  3433 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3434 of main HOL, but was unused); better use HOL's datatype package;
  3435 
  3436 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3437 the old syntax may be recovered as follows:
  3438 
  3439   syntax (symbols)
  3440     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3441       (infixl "\\<oplus>" 100)
  3442 
  3443 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3444 
  3445 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3446 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3447 internally;
  3448 
  3449 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3450 changed from A/r to A//r;
  3451 
  3452 * ZF: new treatment of arithmetic (nat & int) may break some old
  3453 proofs;
  3454 
  3455 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3456 rulify -> rule_format, elimify -> elim_format, ...);
  3457 
  3458 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3459 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3460 should have to change intro!! to intro? only); replaced "delrule" by
  3461 "rule del";
  3462 
  3463 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3464 
  3465 * Provers: strengthened force_tac by using new first_best_tac;
  3466 
  3467 * LaTeX document preparation: several changes of isabelle.sty (see
  3468 lib/texinputs);
  3469 
  3470 
  3471 *** Document preparation ***
  3472 
  3473 * formal comments (text blocks etc.) in new-style theories may now
  3474 contain antiquotations of thm/prop/term/typ/text to be presented
  3475 according to latex print mode; concrete syntax is like this:
  3476 @{term[show_types] "f(x) = a + x"};
  3477 
  3478 * isatool mkdir provides easy setup of Isabelle session directories,
  3479 including proper document sources;
  3480 
  3481 * generated LaTeX sources are now deleted after successful run
  3482 (isatool document -c); may retain a copy somewhere else via -D option
  3483 of isatool usedir;
  3484 
  3485 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3486 style files, achieving self-contained LaTeX sources and simplifying
  3487 LaTeX debugging;
  3488 
  3489 * old-style theories now produce (crude) LaTeX output as well;
  3490 
  3491 * browser info session directories are now self-contained (may be put
  3492 on WWW server seperately); improved graphs of nested sessions; removed
  3493 graph for 'all sessions';
  3494 
  3495 * several improvements in isabelle style files; \isabellestyle{it}
  3496 produces fake math mode output; \isamarkupheader is now \section by
  3497 default; see lib/texinputs/isabelle.sty etc.;
  3498 
  3499 
  3500 *** Isar ***
  3501 
  3502 * Isar/Pure: local results and corresponding term bindings are now
  3503 subject to Hindley-Milner polymorphism (similar to ML); this
  3504 accommodates incremental type-inference very nicely;
  3505 
  3506 * Isar/Pure: new derived language element 'obtain' supports
  3507 generalized existence reasoning;
  3508 
  3509 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3510 support accumulation of results, without applying any rules yet;
  3511 useful to collect intermediate results without explicit name
  3512 references, and for use with transitivity rules with more than 2
  3513 premises;
  3514 
  3515 * Isar/Pure: scalable support for case-analysis type proofs: new
  3516 'case' language element refers to local contexts symbolically, as
  3517 produced by certain proof methods; internally, case names are attached
  3518 to theorems as "tags";
  3519 
  3520 * Isar/Pure: theory command 'hide' removes declarations from
  3521 class/type/const name spaces;
  3522 
  3523 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3524 indicate potential overloading;
  3525 
  3526 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3527 
  3528 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3529 "{a,b,c}" instead of {a,b,c};
  3530 
  3531 * Isar/Pure now provides its own version of intro/elim/dest
  3532 attributes; useful for building new logics, but beware of confusion
  3533 with the version in Provers/classical;
  3534 
  3535 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3536 case name 'antecedent';
  3537 
  3538 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3539 to the current context is now done automatically);
  3540 
  3541 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3542 for definining proof methods in ML;
  3543 
  3544 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3545 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3546 most cases, one should have to change intro!! to intro? only);
  3547 replaced "delrule" by "rule del";
  3548 
  3549 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3550 'symmetric' attribute (the latter supercedes [RS sym]);
  3551 
  3552 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3553 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3554 well (including splits);
  3555 
  3556 * Isar/Provers: Simplifier and Classical methods now support all kind
  3557 of modifiers used in the past, including 'cong', 'iff', etc.
  3558 
  3559 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3560 of Simplifier and Classical reasoner);
  3561 
  3562 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3563 now support named cases; major packages (inductive, datatype, primrec,
  3564 recdef) support case names and properly name parameters;
  3565 
  3566 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3567 monotonicity conditions are extracted to be proven at end of
  3568 calculations;
  3569 
  3570 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3571 method anyway;
  3572 
  3573 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3574 split_if split_if_asm; datatype package provides theorems foo.splits =
  3575 foo.split foo.split_asm for each datatype;
  3576 
  3577 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3578 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3579 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3580 use "(cases (simplified))" method in proper proof texts);
  3581 
  3582 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3583 
  3584 * Isar: names of theorems etc. may be natural numbers as well;
  3585 
  3586 * Isar: 'pr' command: optional arguments for goals_limit and
  3587 ProofContext.prems_limit; no longer prints theory contexts, but only
  3588 proof states;
  3589 
  3590 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3591 additional print modes to be specified; e.g. "pr(latex)" will print
  3592 proof state according to the Isabelle LaTeX style;
  3593 
  3594 * Isar: improved support for emulating tactic scripts, including proof
  3595 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3596 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3597 (for HOL datatypes);
  3598 
  3599 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3600 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3601 'proof method scripts' have to be in depth-first order;
  3602 
  3603 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3604 
  3605 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3606 should instead use individual commands for printing items
  3607 (print_commands, print_methods etc.);
  3608 
  3609 * Isar: added 'nothing' --- the empty list of theorems;
  3610 
  3611 
  3612 *** HOL ***
  3613 
  3614 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3615 corresponding virtual machine and a specification of its bytecode
  3616 verifier and a lightweight bytecode verifier, including proofs of
  3617 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3618 Cornelia Pusch (see also the homepage of project Bali at
  3619 http://isabelle.in.tum.de/Bali/);
  3620 
  3621 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3622 Clemens Ballarin;
  3623 
  3624 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3625 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3626 Rasmussen;
  3627 
  3628 * HOL/Lattice: fundamental concepts of lattice theory and order
  3629 structures, including duals, properties of bounds versus algebraic
  3630 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3631 Theorem for complete lattices etc.; may also serve as a demonstration
  3632 for abstract algebraic reasoning using axiomatic type classes, and
  3633 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3634 
  3635 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3636 von Oheimb;
  3637 
  3638 * HOL/IMPP: extension of IMP with local variables and mutually
  3639 recursive procedures, by David von Oheimb;
  3640 
  3641 * HOL/Lambda: converted into new-style theory and document;
  3642 
  3643 * HOL/ex/Multiquote: example of multiple nested quotations and
  3644 anti-quotations -- basically a generalized version of de-Bruijn
  3645 representation; very useful in avoiding lifting of operations;
  3646 
  3647 * HOL/record: added general record equality rule to simpset; fixed
  3648 select-update simplification procedure to handle extended records as
  3649 well; admit "r" as field name;
  3650 
  3651 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3652 other numeric types and also as the identity of groups, rings, etc.;
  3653 
  3654 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3655 Types nat and int belong to this axclass;
  3656 
  3657 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3658    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3659    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3660   two terms #m*u and #n*u are replaced by #(m+n)*u
  3661     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3662   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3663     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3664 
  3665 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3666 powerful prover for predicate logic but knows nothing of clasets; see
  3667 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3668 
  3669 * HOL: new version of "case_tac" subsumes both boolean case split and
  3670 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3671 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3672 
  3673 * HOL: simplification no longer dives into case-expressions: only the
  3674 selector expression is simplified, but not the remaining arms; to
  3675 enable full simplification of case-expressions for datatype t, you may
  3676 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3677 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3678 
  3679 * HOL/recdef: the recursion equations generated by 'recdef' for
  3680 function 'f' are now called f.simps instead of f.rules; if all
  3681 termination conditions are proved automatically, these simplification
  3682 rules are added to the simpset, as in primrec; rules may be named
  3683 individually as well, resulting in a separate list of theorems for
  3684 each equation;
  3685 
  3686 * HOL/While is a new theory that provides a while-combinator. It
  3687 permits the definition of tail-recursive functions without the
  3688 provision of a termination measure. The latter is necessary once the
  3689 invariant proof rule for while is applied.
  3690 
  3691 * HOL: new (overloaded) notation for the set of elements below/above
  3692 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3693 
  3694 * HOL: theorems impI, allI, ballI bound as "strip";
  3695 
  3696 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3697 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3698 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3699 
  3700 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3701 
  3702 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3703 main HOL, but was unused);
  3704 
  3705 * HOL: fewer consts declared as global (e.g. have to refer to
  3706 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3707 
  3708 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3709 in case of overlap with user translations (e.g. judgements over
  3710 tuples); (note that the underlying logical represenation is still
  3711 bogus);
  3712 
  3713 
  3714 *** ZF ***
  3715 
  3716 * ZF: simplification automatically cancels common terms in arithmetic
  3717 expressions over nat and int;
  3718 
  3719 * ZF: new treatment of nat to minimize type-checking: all operators
  3720 coerce their operands to a natural number using the function natify,
  3721 making the algebraic laws unconditional;
  3722 
  3723 * ZF: as above, for int: operators coerce their operands to an integer
  3724 using the function intify;
  3725 
  3726 * ZF: the integer library now contains many of the usual laws for the
  3727 orderings, including $<=, and monotonicity laws for $+ and $*;
  3728 
  3729 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3730 simplification;
  3731 
  3732 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3733 to the simplifier and classical reasoner simultaneously;
  3734 
  3735 
  3736 *** General ***
  3737 
  3738 * Provers: blast_tac now handles actual object-logic rules as
  3739 assumptions; note that auto_tac uses blast_tac internally as well;
  3740 
  3741 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3742 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3743 
  3744 * Provers: delrules now handles destruct rules as well (no longer need
  3745 explicit make_elim);
  3746 
  3747 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3748   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3749 use instead the strong form,
  3750   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3751 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3752 from destruct-rules;
  3753 
  3754 * Provers: Simplifier.easy_setup provides a fast path to basic
  3755 Simplifier setup for new object-logics;
  3756 
  3757 * Pure: AST translation rules no longer require constant head on LHS;
  3758 
  3759 * Pure: improved name spaces: ambiguous output is qualified; support
  3760 for hiding of names;
  3761 
  3762 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3763 XSYMBOL_HOME; no longer need to do manual configuration in most
  3764 situations;
  3765 
  3766 * system: compression of ML heaps images may now be controlled via -c
  3767 option of isabelle and isatool usedir (currently only observed by
  3768 Poly/ML);
  3769 
  3770 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3771 useful for remote X11);
  3772 
  3773 * system: provide TAGS file for Isabelle sources;
  3774 
  3775 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3776 order;
  3777 
  3778 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3779 timing flag supersedes proof_timing and Toplevel.trace;
  3780 
  3781 * ML: new combinators |>> and |>>> for incremental transformations
  3782 with secondary results (e.g. certain theory extensions):
  3783 
  3784 * ML: PureThy.add_defs gets additional argument to indicate potential
  3785 overloading (usually false);
  3786 
  3787 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3788 results;
  3789 
  3790 
  3791 
  3792 New in Isabelle99 (October 1999)
  3793 --------------------------------
  3794 
  3795 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3796 
  3797 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3798 are no longer simplified.  (This allows the simplifier to unfold recursive
  3799 functional programs.)  To restore the old behaviour, declare
  3800 
  3801     Delcongs [if_weak_cong];
  3802 
  3803 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3804 complement;
  3805 
  3806 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3807 
  3808 * HOL/datatype: mutual_induct_tac no longer exists --
  3809   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3810 
  3811 * HOL/typedef: fixed type inference for representing set; type
  3812 arguments now have to occur explicitly on the rhs as type constraints;
  3813 
  3814 * ZF: The con_defs part of an inductive definition may no longer refer
  3815 to constants declared in the same theory;
  3816 
  3817 * HOL, ZF: the function mk_cases, generated by the inductive
  3818 definition package, has lost an argument.  To simplify its result, it
  3819 uses the default simpset instead of a supplied list of theorems.
  3820 
  3821 * HOL/List: the constructors of type list are now Nil and Cons;
  3822 
  3823 * Simplifier: the type of the infix ML functions
  3824         setSSolver addSSolver setSolver addSolver
  3825 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3826 for packaging solvers. A solver is created via
  3827         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3828 where the string argument is only a comment.
  3829 
  3830 
  3831 *** Proof tools ***
  3832 
  3833 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3834 decision procedure for linear arithmetic. Currently it is used for
  3835 types `nat', `int', and `real' in HOL (see below); it can, should and
  3836 will be instantiated for other types and logics as well.
  3837 
  3838 * The simplifier now accepts rewrite rules with flexible heads, eg
  3839      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3840   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3841   matching.
  3842 
  3843 
  3844 *** General ***
  3845 
  3846 * New Isabelle/Isar subsystem provides an alternative to traditional
  3847 tactical theorem proving; together with the ProofGeneral/isar user
  3848 interface it offers an interactive environment for developing human
  3849 readable proof documents (Isar == Intelligible semi-automated
  3850 reasoning); for further information see isatool doc isar-ref,
  3851 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3852 
  3853 * improved and simplified presentation of theories: better HTML markup
  3854 (including colors), graph views in several sizes; isatool usedir now
  3855 provides a proper interface for user theories (via -P option); actual
  3856 document preparation based on (PDF)LaTeX is available as well (for
  3857 new-style theories only); see isatool doc system for more information;
  3858 
  3859 * native support for Proof General, both for classic Isabelle and
  3860 Isabelle/Isar;
  3861 
  3862 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3863 using the graph browser tool;
  3864 
  3865 * Isabelle manuals now also available as PDF;
  3866 
  3867 * theory loader rewritten from scratch (may not be fully
  3868 bug-compatible); old loadpath variable has been replaced by show_path,
  3869 add_path, del_path, reset_path functions; new operations such as
  3870 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3871 isatool doc ref);
  3872 
  3873 * improved isatool install: option -k creates KDE application icon,
  3874 option -p DIR installs standalone binaries;
  3875 
  3876 * added ML_PLATFORM setting (useful for cross-platform installations);
  3877 more robust handling of platform specific ML images for SML/NJ;
  3878 
  3879 * the settings environment is now statically scoped, i.e. it is never
  3880 created again in sub-processes invoked from isabelle, isatool, or
  3881 Isabelle;
  3882 
  3883 * path element specification '~~' refers to '$ISABELLE_HOME';
  3884 
  3885 * in locales, the "assumes" and "defines" parts may be omitted if
  3886 empty;
  3887 
  3888 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3889 long arrows);
  3890 
  3891 * new print_mode "HTML";
  3892 
  3893 * new flag show_tags controls display of tags of theorems (which are
  3894 basically just comments that may be attached by some tools);
  3895 
  3896 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3897 mode and goal output format:
  3898 
  3899 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3900 244c244
  3901 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3902 ---
  3903 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3904 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3905 181c181
  3906 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3907 ---
  3908 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3909 
  3910 * function bind_thms stores lists of theorems (cf. bind_thm);
  3911 
  3912 * new shorthand tactics ftac, eatac, datac, fatac;
  3913 
  3914 * qed (and friends) now accept "" as result name; in that case the
  3915 theorem is not stored, but proper checks and presentation of the
  3916 result still apply;
  3917 
  3918 * theorem database now also indexes constants "Trueprop", "all",
  3919 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3920 
  3921 
  3922 *** HOL ***
  3923 
  3924 ** HOL arithmetic **
  3925 
  3926 * There are now decision procedures for linear arithmetic over nat and
  3927 int:
  3928 
  3929 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3930 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3931 are treated as atomic; subformulae not involving type `nat' or `int'
  3932 are ignored; quantified subformulae are ignored unless they are
  3933 positive universal or negative existential. The tactic has to be
  3934 invoked by hand and can be a little bit slow. In particular, the
  3935 running time is exponential in the number of occurrences of `min' and
  3936 `max', and `-' on `nat'.
  3937 
  3938 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3939 (negated) (in)equalities among the premises and the conclusion into
  3940 account (i.e. no compound formulae) and does not know about `min' and
  3941 `max', and `-' on `nat'. It is fast and is used automatically by the
  3942 simplifier.
  3943 
  3944 NB: At the moment, these decision procedures do not cope with mixed
  3945 nat/int formulae where the two parts interact, such as `m < n ==>
  3946 int(m) < int(n)'.
  3947 
  3948 * HOL/Numeral provides a generic theory of numerals (encoded
  3949 efficiently as bit strings); setup for types nat/int/real is in place;
  3950 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3951 int, existing theories and proof scripts may require a few additional
  3952 type constraints;
  3953 
  3954 * integer division and remainder can now be performed on constant
  3955 arguments;
  3956 
  3957 * many properties of integer multiplication, division and remainder
  3958 are now available;
  3959 
  3960 * An interface to the Stanford Validity Checker (SVC) is available through the
  3961 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3962 are proved automatically.  SVC must be installed separately, and its results
  3963 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3964 invocation of the underlying oracle).  For SVC see
  3965   http://verify.stanford.edu/SVC
  3966 
  3967 * IsaMakefile: the HOL-Real target now builds an actual image;
  3968 
  3969 
  3970 ** HOL misc **
  3971 
  3972 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3973 (in Isabelle/Isar) -- by Gertrud Bauer;
  3974 
  3975 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3976 analysis for assembly languages with subtypes;
  3977 
  3978 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3979 -- avoids syntactic ambiguities and treats state, transition, and
  3980 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3981 changed syntax and (many) tactics;
  3982 
  3983 * HOL/inductive: Now also handles more general introduction rules such
  3984   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3985   theorems are now maintained within the theory (maintained via the
  3986   "mono" attribute);
  3987 
  3988 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3989   (using function types) such as
  3990 
  3991   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3992 
  3993 * HOL/record: record_simproc (part of the default simpset) takes care
  3994 of selectors applied to updated records; record_split_tac is no longer
  3995 part of the default claset; update_defs may now be removed from the
  3996 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3997 
  3998   claset_ref () := claset() addSWrapper record_split_wrapper;
  3999   Delsimprocs [record_simproc]
  4000 
  4001 * HOL/typedef: fixed type inference for representing set; type
  4002 arguments now have to occur explicitly on the rhs as type constraints;
  4003 
  4004 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4005 names rather than an ML expression;
  4006 
  4007 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4008 supplied later.  Program schemes can be defined, such as
  4009     "While B C s = (if B s then While B C (C s) else s)"
  4010 where the well-founded relation can be chosen after B and C have been given.
  4011 
  4012 * HOL/List: the constructors of type list are now Nil and Cons;
  4013 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4014 course, ML tools referring to List.list.op # etc. have to be adapted;
  4015 
  4016 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4017 disabled by default; run isabelle with option -m HOL to get back to
  4018 the original Gordon/HOL-style output;
  4019 
  4020 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4021 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4022 
  4023 * HOL basic syntax simplified (more orthogonal): all variants of
  4024 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4025 Eps operator is provided as well: "SOME x. P[x]";
  4026 
  4027 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4028 
  4029 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4030 thus available for user theories;
  4031 
  4032 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4033 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4034 time;
  4035 
  4036 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4037 several times and then mp;
  4038 
  4039 
  4040 *** LK ***
  4041 
  4042 * the notation <<...>> is now available as a notation for sequences of
  4043 formulas;
  4044 
  4045 * the simplifier is now installed
  4046 
  4047 * the axiom system has been generalized (thanks to Soren Heilmann)
  4048 
  4049 * the classical reasoner now has a default rule database
  4050 
  4051 
  4052 *** ZF ***
  4053 
  4054 * new primrec section allows primitive recursive functions to be given
  4055 directly (as in HOL) over datatypes and the natural numbers;
  4056 
  4057 * new tactics induct_tac and exhaust_tac for induction (or case
  4058 analysis) over datatypes and the natural numbers;
  4059 
  4060 * the datatype declaration of type T now defines the recursor T_rec;
  4061 
  4062 * simplification automatically does freeness reasoning for datatype
  4063 constructors;
  4064 
  4065 * automatic type-inference, with AddTCs command to insert new
  4066 type-checking rules;
  4067 
  4068 * datatype introduction rules are now added as Safe Introduction rules
  4069 to the claset;
  4070 
  4071 * the syntax "if P then x else y" is now available in addition to
  4072 if(P,x,y);
  4073 
  4074 
  4075 *** Internal programming interfaces ***
  4076 
  4077 * tuned simplifier trace output; new flag debug_simp;
  4078 
  4079 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4080 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4081 
  4082 * AxClass.axclass_tac lost the theory argument;
  4083 
  4084 * tuned current_goals_markers semantics: begin / end goal avoids
  4085 printing empty lines;
  4086 
  4087 * removed prs and prs_fn hook, which was broken because it did not
  4088 include \n in its semantics, forcing writeln to add one
  4089 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4090 string -> unit if you really want to output text without newline;
  4091 
  4092 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4093 plain output, interface builders may have to enable 'isabelle_font'
  4094 mode to get Isabelle font glyphs as before;
  4095 
  4096 * refined token_translation interface; INCOMPATIBILITY: output length
  4097 now of type real instead of int;
  4098 
  4099 * theory loader actions may be traced via new ThyInfo.add_hook
  4100 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4101 your own database of information attached to *whole* theories -- as
  4102 opposed to intra-theory data slots offered via TheoryDataFun;
  4103 
  4104 * proper handling of dangling sort hypotheses (at last!);
  4105 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4106 extra sort hypotheses that can be witnessed from the type signature;
  4107 the force_strip_shyps flag is gone, any remaining shyps are simply
  4108 left in the theorem (with a warning issued by strip_shyps_warning);
  4109 
  4110 
  4111 
  4112 New in Isabelle98-1 (October 1998)
  4113 ----------------------------------
  4114 
  4115 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4116 
  4117 * several changes of automated proof tools;
  4118 
  4119 * HOL: major changes to the inductive and datatype packages, including
  4120 some minor incompatibilities of theory syntax;
  4121 
  4122 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4123 called `inj_on';
  4124 
  4125 * HOL: removed duplicate thms in Arith:
  4126   less_imp_add_less  should be replaced by  trans_less_add1
  4127   le_imp_add_le      should be replaced by  trans_le_add1
  4128 
  4129 * HOL: unary minus is now overloaded (new type constraints may be
  4130 required);
  4131 
  4132 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4133 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4134 now taken as an integer constant.
  4135 
  4136 * Pure: ML function 'theory_of' renamed to 'theory';
  4137 
  4138 
  4139 *** Proof tools ***
  4140 
  4141 * Simplifier:
  4142   1. Asm_full_simp_tac is now more aggressive.
  4143      1. It will sometimes reorient premises if that increases their power to
  4144         simplify.
  4145      2. It does no longer proceed strictly from left to right but may also
  4146         rotate premises to achieve further simplification.
  4147      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4148      old Asm_full_simp_tac in that it does not rotate premises.
  4149   2. The simplifier now knows a little bit about nat-arithmetic.
  4150 
  4151 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4152 allows for selected deletion of wrappers, by introduction of names for
  4153 wrapper functionals.  This implies that addbefore, addSbefore,
  4154 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4155 and that adding two tactics with the same name overwrites the first
  4156 one (emitting a warning).
  4157   type wrapper = (int -> tactic) -> (int -> tactic)
  4158   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4159   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4160   delWrapper, delSWrapper: claset *  string            -> claset
  4161   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4162 
  4163 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4164 semantics; addbefore now affects only the unsafe part of step_tac
  4165 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4166 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4167 by Force_tac;
  4168 
  4169 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4170 compWrapper; added safe wrapper (and access functions for it);
  4171 
  4172 * HOL/split_all_tac is now much faster and fails if there is nothing
  4173 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4174 and the names of the automatically generated variables have changed.
  4175 split_all_tac has moved within claset() from unsafe wrappers to safe
  4176 wrappers, which means that !!-bound variables are split much more
  4177 aggressively, and safe_tac and clarify_tac now split such variables.
  4178 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4179 Note: the same holds for record_split_tac, which does the job of
  4180 split_all_tac for record fields.
  4181 
  4182 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4183 permanently to the default simpset using Addsplits just like
  4184 Addsimps. They can be removed via Delsplits just like
  4185 Delsimps. Lower-case versions are also available.
  4186 
  4187 * HOL/Simplifier: The rule split_if is now part of the default
  4188 simpset. This means that the simplifier will eliminate all occurrences
  4189 of if-then-else in the conclusion of a goal. To prevent this, you can
  4190 either remove split_if completely from the default simpset by
  4191 `Delsplits [split_if]' or remove it in a specific call of the
  4192 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4193 other case splitting rules to/from the default simpset: every datatype
  4194 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4195 t is the name of the datatype).
  4196 
  4197 * Classical reasoner / Simplifier combination: new force_tac (and
  4198 derivatives Force_tac, force) combines rewriting and classical
  4199 reasoning (and whatever other tools) similarly to auto_tac, but is
  4200 aimed to solve the given subgoal completely.
  4201 
  4202 
  4203 *** General ***
  4204 
  4205 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4206 and `goalw': the theory is no longer needed as an explicit argument -
  4207 the current theory context is used; assumptions are no longer returned
  4208 at the ML-level unless one of them starts with ==> or !!; it is
  4209 recommended to convert to these new commands using isatool fixgoal
  4210 (backup your sources first!);
  4211 
  4212 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4213 the current theory context, and 'theory' to lookup stored theories;
  4214 
  4215 * new theory section 'locale' for declaring constants, assumptions and
  4216 definitions that have local scope;
  4217 
  4218 * new theory section 'nonterminals' for purely syntactic types;
  4219 
  4220 * new theory section 'setup' for generic ML setup functions
  4221 (e.g. package initialization);
  4222 
  4223 * the distribution now includes Isabelle icons: see
  4224 lib/logo/isabelle-{small,tiny}.xpm;
  4225 
  4226 * isatool install - install binaries with absolute references to
  4227 ISABELLE_HOME/bin;
  4228 
  4229 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4230 
  4231 * print mode 'emacs' reserved for Isamode;
  4232 
  4233 * support multiple print (ast) translations per constant name;
  4234 
  4235 * theorems involving oracles are now printed with a suffixed [!];
  4236 
  4237 
  4238 *** HOL ***
  4239 
  4240 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4241 
  4242 * HOL/inductive package reorganized and improved: now supports mutual
  4243 definitions such as
  4244 
  4245   inductive EVEN ODD
  4246     intrs
  4247       null "0 : EVEN"
  4248       oddI "n : EVEN ==> Suc n : ODD"
  4249       evenI "n : ODD ==> Suc n : EVEN"
  4250 
  4251 new theorem list "elims" contains an elimination rule for each of the
  4252 recursive sets; inductive definitions now handle disjunctive premises
  4253 correctly (also ZF);
  4254 
  4255 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4256 "mutual_induct" no longer exists - the induction rule is always
  4257 contained in "induct";
  4258 
  4259 
  4260 * HOL/datatype package re-implemented and greatly improved: now
  4261 supports mutually recursive datatypes such as
  4262 
  4263   datatype
  4264     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4265             | SUM ('a aexp) ('a aexp)
  4266             | DIFF ('a aexp) ('a aexp)
  4267             | NUM 'a
  4268   and
  4269     'a bexp = LESS ('a aexp) ('a aexp)
  4270             | AND ('a bexp) ('a bexp)
  4271             | OR ('a bexp) ('a bexp)
  4272 
  4273 as well as indirectly recursive datatypes such as
  4274 
  4275   datatype
  4276     ('a, 'b) term = Var 'a
  4277                   | App 'b ((('a, 'b) term) list)
  4278 
  4279 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4280 induction on mutually / indirectly recursive datatypes.
  4281 
  4282 Primrec equations are now stored in theory and can be accessed via
  4283 <function_name>.simps.
  4284 
  4285 INCOMPATIBILITIES:
  4286 
  4287   - Theories using datatypes must now have theory Datatype as an
  4288     ancestor.
  4289   - The specific <typename>.induct_tac no longer exists - use the
  4290     generic induct_tac instead.
  4291   - natE has been renamed to nat.exhaust - use exhaust_tac
  4292     instead of res_inst_tac ... natE. Note that the variable
  4293     names in nat.exhaust differ from the names in natE, this
  4294     may cause some "fragile" proofs to fail.
  4295   - The theorems split_<typename>_case and split_<typename>_case_asm
  4296     have been renamed to <typename>.split and <typename>.split_asm.
  4297   - Since default sorts of type variables are now handled correctly,
  4298     some datatype definitions may have to be annotated with explicit
  4299     sort constraints.
  4300   - Primrec definitions no longer require function name and type
  4301     of recursive argument.
  4302 
  4303 Consider using isatool fixdatatype to adapt your theories and proof
  4304 scripts to the new package (backup your sources first!).
  4305 
  4306 
  4307 * HOL/record package: considerably improved implementation; now
  4308 includes concrete syntax for record types, terms, updates; theorems
  4309 for surjective pairing and splitting !!-bound record variables; proof
  4310 support is as follows:
  4311 
  4312   1) standard conversions (selectors or updates applied to record
  4313 constructor terms) are part of the standard simpset;
  4314 
  4315   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4316 made part of standard simpset and claset via addIffs;
  4317 
  4318   3) a tactic for record field splitting (record_split_tac) is part of
  4319 the standard claset (addSWrapper);
  4320 
  4321 To get a better idea about these rules you may retrieve them via
  4322 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4323 the name of your record type.
  4324 
  4325 The split tactic 3) conceptually simplifies by the following rule:
  4326 
  4327   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4328 
  4329 Thus any record variable that is bound by meta-all will automatically
  4330 blow up into some record constructor term, consequently the
  4331 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4332 solve record problems automatically.
  4333 
  4334 
  4335 * reorganized the main HOL image: HOL/Integ and String loaded by
  4336 default; theory Main includes everything;
  4337 
  4338 * automatic simplification of integer sums and comparisons, using cancellation;
  4339 
  4340 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4341 
  4342 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4343 
  4344 * many new identities for unions, intersections, set difference, etc.;
  4345 
  4346 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4347 called split_if, split_split, split_sum_case and split_nat_case (to go
  4348 with add/delsplits);
  4349 
  4350 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4351 (?x::unit) = (); this is made part of the default simpset, which COULD
  4352 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4353 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4354 unit_abs_eta_conv is added in order to counter the effect of
  4355 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4356 %u.f();
  4357 
  4358 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4359 makes more sense);
  4360 
  4361 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4362   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4363   disjointness reasoning but breaking a few old proofs.
  4364 
  4365 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4366 to 'converse' from 'inverse' (for compatibility with ZF and some
  4367 literature);
  4368 
  4369 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4370 the well-founded relation;
  4371 
  4372 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4373     Compl A.  The "Compl" syntax remains available as input syntax for this
  4374     release ONLY.
  4375 
  4376 * HOL/Update: new theory of function updates:
  4377     f(a:=b) == %x. if x=a then b else f x
  4378 may also be iterated as in f(a:=b,c:=d,...);
  4379 
  4380 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4381 
  4382 * HOL/List:
  4383   - new function list_update written xs[i:=v] that updates the i-th
  4384     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4385   - new function `upt' written [i..j(] which generates the list
  4386     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4387     bound write [i..j], which is a shorthand for [i..j+1(].
  4388   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4389 
  4390 * HOL/Arith:
  4391   - removed 'pred' (predecessor) function;
  4392   - generalized some theorems about n-1;
  4393   - many new laws about "div" and "mod";
  4394   - new laws about greatest common divisors (see theory ex/Primes);
  4395 
  4396 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4397 instead of "inverse";
  4398 
  4399 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4400   of the multiset ordering;
  4401 
  4402 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4403   (not included by default);
  4404 
  4405 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4406 
  4407 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4408   programs, i.e. different program variables may have different types.
  4409 
  4410 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4411   [previously, this check worked only if the rewrite rule was unconditional]
  4412   Now rew can involve either definitions or equalities (either == or =).
  4413 
  4414 
  4415 *** ZF ***
  4416 
  4417 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4418   only the theorems proved on ZF.ML;
  4419 
  4420 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4421   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4422   disjointness reasoning but breaking a few old proofs.
  4423 
  4424 * ZF/Update: new theory of function updates
  4425     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4426   may also be iterated as in f(a:=b,c:=d,...);
  4427 
  4428 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4429 
  4430 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4431   [previously, this check worked only if the rewrite rule was unconditional]
  4432   Now rew can involve either definitions or equalities (either == or =).
  4433 
  4434 * case_tac provided for compatibility with HOL
  4435     (like the old excluded_middle_tac, but with subgoals swapped)
  4436 
  4437 
  4438 *** Internal programming interfaces ***
  4439 
  4440 * Pure: several new basic modules made available for general use, see
  4441 also src/Pure/README;
  4442 
  4443 * improved the theory data mechanism to support encapsulation (data
  4444 kind name replaced by private Object.kind, acting as authorization
  4445 key); new type-safe user interface via functor TheoryDataFun; generic
  4446 print_data function becomes basically useless;
  4447 
  4448 * removed global_names compatibility flag -- all theory declarations
  4449 are qualified by default;
  4450 
  4451 * module Pure/Syntax now offers quote / antiquote translation
  4452 functions (useful for Hoare logic etc. with implicit dependencies);
  4453 see HOL/ex/Antiquote for an example use;
  4454 
  4455 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4456 cterm -> thm;
  4457 
  4458 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4459 subgoal;
  4460 
  4461 * Display.print_goals function moved to Locale.print_goals;
  4462 
  4463 * standard print function for goals supports current_goals_markers
  4464 variable for marking begin of proof, end of proof, start of goal; the
  4465 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4466 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4467 for example;
  4468 
  4469 
  4470 
  4471 New in Isabelle98 (January 1998)
  4472 --------------------------------
  4473 
  4474 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4475 
  4476 * changed lexical syntax of terms / types: dots made part of long
  4477 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4478 
  4479 * simpset (and claset) reference variable replaced by functions
  4480 simpset / simpset_ref;
  4481 
  4482 * no longer supports theory aliases (via merge) and non-trivial
  4483 implicit merge of thms' signatures;
  4484 
  4485 * most internal names of constants changed due to qualified names;
  4486 
  4487 * changed Pure/Sequence interface (see Pure/seq.ML);
  4488 
  4489 
  4490 *** General Changes ***
  4491 
  4492 * hierachically structured name spaces (for consts, types, axms, thms
  4493 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4494 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4495 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4496 long_names for fully qualified output names; NOTE: ML programs
  4497 (special tactics, packages etc.) referring to internal names may have
  4498 to be adapted to cope with fully qualified names; in case of severe
  4499 backward campatibility problems try setting 'global_names' at compile
  4500 time to have enrything declared within a flat name space; one may also
  4501 fine tune name declarations in theories via the 'global' and 'local'
  4502 section;
  4503 
  4504 * reimplemented the implicit simpset and claset using the new anytype
  4505 data filed in signatures; references simpset:simpset ref etc. are
  4506 replaced by functions simpset:unit->simpset and
  4507 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4508 to patch your ML files accordingly;
  4509 
  4510 * HTML output now includes theory graph data for display with Java
  4511 applet or isatool browser; data generated automatically via isatool
  4512 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4513 
  4514 * defs may now be conditional; improved rewrite_goals_tac to handle
  4515 conditional equations;
  4516 
  4517 * defs now admits additional type arguments, using TYPE('a) syntax;
  4518 
  4519 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4520 creates a new theory node; implicit merge of thms' signatures is
  4521 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4522 transfer:theory->thm->thm in (rare) cases;
  4523 
  4524 * improved handling of draft signatures / theories; draft thms (and
  4525 ctyps, cterms) are automatically promoted to real ones;
  4526 
  4527 * slightly changed interfaces for oracles: admit many per theory, named
  4528 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4529 
  4530 * print_goals: optional output of const types (set show_consts and
  4531 show_types);
  4532 
  4533 * improved output of warnings (###) and errors (***);
  4534 
  4535 * subgoal_tac displays a warning if the new subgoal has type variables;
  4536 
  4537 * removed old README and Makefiles;
  4538 
  4539 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4540 
  4541 * removed obsolete init_pps and init_database;
  4542 
  4543 * deleted the obsolete tactical STATE, which was declared by
  4544     fun STATE tacfun st = tacfun st st;
  4545 
  4546 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4547 (which abbreviates $HOME);
  4548 
  4549 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4550 use isatool fixseq to adapt your ML programs (this works for fully
  4551 qualified references to the Sequence structure only!);
  4552 
  4553 * use_thy no longer requires writable current directory; it always
  4554 reloads .ML *and* .thy file, if either one is out of date;
  4555 
  4556 
  4557 *** Classical Reasoner ***
  4558 
  4559 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4560 tactics that use classical reasoning to simplify a subgoal without
  4561 splitting it into several subgoals;
  4562 
  4563 * Safe_tac: like safe_tac but uses the default claset;
  4564 
  4565 
  4566 *** Simplifier ***
  4567 
  4568 * added simplification meta rules:
  4569     (asm_)(full_)simplify: simpset -> thm -> thm;
  4570 
  4571 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4572 logics (again);
  4573 
  4574 * added prems argument to simplification procedures;
  4575 
  4576 * HOL, FOL, ZF: added infix function `addsplits':
  4577   instead of `<simpset> setloop (split_tac <thms>)'
  4578   you can simply write `<simpset> addsplits <thms>'
  4579 
  4580 
  4581 *** Syntax ***
  4582 
  4583 * TYPE('a) syntax for type reflection terms;
  4584 
  4585 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4586 
  4587 * pretty printer: changed order of mixfix annotation preference (again!);
  4588 
  4589 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4590 
  4591 
  4592 *** HOL ***
  4593 
  4594 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4595   with `addloop' of the simplifier to faciliate case splitting in premises.
  4596 
  4597 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4598 
  4599 * HOL/Auth: new protocol proofs including some for the Internet
  4600   protocol TLS;
  4601 
  4602 * HOL/Map: new theory of `maps' a la VDM;
  4603 
  4604 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4605 cancelling out common nat summands from =, <, <= (in)equalities, or
  4606 differences; simplification procedures nat_cancel_factor for
  4607 cancelling common factor from =, <, <= (in)equalities over natural
  4608 sums; nat_cancel contains both kinds of procedures, it is installed by
  4609 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4610 
  4611 * HOL/simplifier: terms of the form
  4612   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4613   are rewritten to
  4614   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4615   and those of the form
  4616   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4617   are rewritten to
  4618   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4619 
  4620 * HOL/datatype
  4621   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4622 
  4623   P(t_case f1 ... fn x) =
  4624      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4625         ...
  4626        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4627      )
  4628 
  4629   and a theorem `split_t_case_asm' of the form
  4630 
  4631   P(t_case f1 ... fn x) =
  4632     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4633         ...
  4634        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4635      )
  4636   which can be added to a simpset via `addsplits'. The existing theorems
  4637   expand_list_case and expand_option_case have been renamed to
  4638   split_list_case and split_option_case.
  4639 
  4640 * HOL/Arithmetic:
  4641   - `pred n' is automatically converted to `n-1'.
  4642     Users are strongly encouraged not to use `pred' any longer,
  4643     because it will disappear altogether at some point.
  4644   - Users are strongly encouraged to write "0 < n" rather than
  4645     "n ~= 0". Theorems and proof tools have been modified towards this
  4646     `standard'.
  4647 
  4648 * HOL/Lists:
  4649   the function "set_of_list" has been renamed "set" (and its theorems too);
  4650   the function "nth" now takes its arguments in the reverse order and
  4651   has acquired the infix notation "!" as in "xs!n".
  4652 
  4653 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4654 
  4655 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4656   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4657 
  4658 * HOL/record: extensible records with schematic structural subtyping
  4659 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4660 still lacks various theorems and concrete record syntax;
  4661 
  4662 
  4663 *** HOLCF ***
  4664 
  4665 * removed "axioms" and "generated by" sections;
  4666 
  4667 * replaced "ops" section by extended "consts" section, which is capable of
  4668   handling the continuous function space "->" directly;
  4669 
  4670 * domain package:
  4671   . proves theorems immediately and stores them in the theory,
  4672   . creates hierachical name space,
  4673   . now uses normal mixfix annotations (instead of cinfix...),
  4674   . minor changes to some names and values (for consistency),
  4675   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4676   . separator between mutual domain defs: changed "," to "and",
  4677   . improved handling of sort constraints;  now they have to
  4678     appear on the left-hand side of the equations only;
  4679 
  4680 * fixed LAM <x,y,zs>.b syntax;
  4681 
  4682 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4683 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4684 
  4685 
  4686 *** FOL and ZF ***
  4687 
  4688 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4689   with `addloop' of the simplifier to faciliate case splitting in premises.
  4690 
  4691 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4692 in HOL, they strip ALL and --> from proved theorems;
  4693 
  4694 
  4695 
  4696 New in Isabelle94-8 (May 1997)
  4697 ------------------------------
  4698 
  4699 *** General Changes ***
  4700 
  4701 * new utilities to build / run / maintain Isabelle etc. (in parts
  4702 still somewhat experimental); old Makefiles etc. still functional;
  4703 
  4704 * new 'Isabelle System Manual';
  4705 
  4706 * INSTALL text, together with ./configure and ./build scripts;
  4707 
  4708 * reimplemented type inference for greater efficiency, better error
  4709 messages and clean internal interface;
  4710 
  4711 * prlim command for dealing with lots of subgoals (an easier way of
  4712 setting goals_limit);
  4713 
  4714 
  4715 *** Syntax ***
  4716 
  4717 * supports alternative (named) syntax tables (parser and pretty
  4718 printer); internal interface is provided by add_modesyntax(_i);
  4719 
  4720 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4721 be used in conjunction with the Isabelle symbol font; uses the
  4722 "symbols" syntax table;
  4723 
  4724 * added token_translation interface (may translate name tokens in
  4725 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4726 the current print_mode); IMPORTANT: user print translation functions
  4727 are responsible for marking newly introduced bounds
  4728 (Syntax.mark_boundT);
  4729 
  4730 * token translations for modes "xterm" and "xterm_color" that display
  4731 names in bold, underline etc. or colors (which requires a color
  4732 version of xterm);
  4733 
  4734 * infixes may now be declared with names independent of their syntax;
  4735 
  4736 * added typed_print_translation (like print_translation, but may
  4737 access type of constant);
  4738 
  4739 
  4740 *** Classical Reasoner ***
  4741 
  4742 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4743 some limitations.  Blast_tac...
  4744   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4745   + ignores elimination rules that don't have the correct format
  4746         (the conclusion MUST be a formula variable)
  4747   + ignores types, which can make HOL proofs fail
  4748   + rules must not require higher-order unification, e.g. apply_type in ZF
  4749     [message "Function Var's argument not a bound variable" relates to this]
  4750   + its proof strategy is more general but can actually be slower
  4751 
  4752 * substitution with equality assumptions no longer permutes other
  4753 assumptions;
  4754 
  4755 * minor changes in semantics of addafter (now called addaltern); renamed
  4756 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4757 (and access functions for it);
  4758 
  4759 * improved combination of classical reasoner and simplifier:
  4760   + functions for handling clasimpsets
  4761   + improvement of addss: now the simplifier is called _after_ the
  4762     safe steps.
  4763   + safe variant of addss called addSss: uses safe simplifications
  4764     _during_ the safe steps. It is more complete as it allows multiple
  4765     instantiations of unknowns (e.g. with slow_tac).
  4766 
  4767 *** Simplifier ***
  4768 
  4769 * added interface for simplification procedures (functions that
  4770 produce *proven* rewrite rules on the fly, depending on current
  4771 redex);
  4772 
  4773 * ordering on terms as parameter (used for ordered rewriting);
  4774 
  4775 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4776 
  4777 * the solver is now split into a safe and an unsafe part.
  4778 This should be invisible for the normal user, except that the
  4779 functions setsolver and addsolver have been renamed to setSolver and
  4780 addSolver; added safe_asm_full_simp_tac;
  4781 
  4782 
  4783 *** HOL ***
  4784 
  4785 * a generic induction tactic `induct_tac' which works for all datatypes and
  4786 also for type `nat';
  4787 
  4788 * a generic case distinction tactic `exhaust_tac' which works for all
  4789 datatypes and also for type `nat';
  4790 
  4791 * each datatype comes with a function `size';
  4792 
  4793 * patterns in case expressions allow tuple patterns as arguments to
  4794 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4795 
  4796 * primrec now also works with type nat;
  4797 
  4798 * recdef: a new declaration form, allows general recursive functions to be
  4799 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4800 
  4801 * the constant for negation has been renamed from "not" to "Not" to
  4802 harmonize with FOL, ZF, LK, etc.;
  4803 
  4804 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4805 infinite lists;
  4806 
  4807 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4808 
  4809 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4810 problems in commutative rings, using axiomatic type classes for + and *;
  4811 
  4812 * more examples in HOL/MiniML and HOL/Auth;
  4813 
  4814 * more default rewrite rules for quantifiers, union/intersection;
  4815 
  4816 * a new constant `arbitrary == @x.False';
  4817 
  4818 * HOLCF/IOA replaces old HOL/IOA;
  4819 
  4820 * HOLCF changes: derived all rules and arities
  4821   + axiomatic type classes instead of classes
  4822   + typedef instead of faking type definitions
  4823   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4824   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4825   + eliminated the types void, one, tr
  4826   + use unit lift and bool lift (with translations) instead of one and tr
  4827   + eliminated blift from Lift3.thy (use Def instead of blift)
  4828   all eliminated rules are derived as theorems --> no visible changes ;
  4829 
  4830 
  4831 *** ZF ***
  4832 
  4833 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4834 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4835 as ZF_cs addSIs [equalityI];
  4836 
  4837 
  4838 
  4839 New in Isabelle94-7 (November 96)
  4840 ---------------------------------
  4841 
  4842 * allowing negative levels (as offsets) in prlev and choplev;
  4843 
  4844 * super-linear speedup for large simplifications;
  4845 
  4846 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4847 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4848 FAIL); can suppress it using the command Delsimps (ex_simps @
  4849 all_simps); De Morgan laws are also now included, by default;
  4850 
  4851 * improved printing of ==>  :  ~:
  4852 
  4853 * new object-logic "Sequents" adds linear logic, while replacing LK
  4854 and Modal (thanks to Sara Kalvala);
  4855 
  4856 * HOL/Auth: correctness proofs for authentication protocols;
  4857 
  4858 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4859 examples on HOL/Auth);
  4860 
  4861 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4862 the rewriter and classical reasoner simultaneously;
  4863 
  4864 * function uresult no longer returns theorems in "standard" format;
  4865 regain previous version by: val uresult = standard o uresult;
  4866 
  4867 
  4868 
  4869 New in Isabelle94-6
  4870 -------------------
  4871 
  4872 * oracles -- these establish an interface between Isabelle and trusted
  4873 external reasoners, which may deliver results as theorems;
  4874 
  4875 * proof objects (in particular record all uses of oracles);
  4876 
  4877 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4878 
  4879 * "constdefs" section in theory files;
  4880 
  4881 * "primrec" section (HOL) no longer requires names;
  4882 
  4883 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4884 
  4885 
  4886 
  4887 New in Isabelle94-5
  4888 -------------------
  4889 
  4890 * reduced space requirements;
  4891 
  4892 * automatic HTML generation from theories;
  4893 
  4894 * theory files no longer require "..." (quotes) around most types;
  4895 
  4896 * new examples, including two proofs of the Church-Rosser theorem;
  4897 
  4898 * non-curried (1994) version of HOL is no longer distributed;
  4899 
  4900 
  4901 
  4902 New in Isabelle94-4
  4903 -------------------
  4904 
  4905 * greatly reduced space requirements;
  4906 
  4907 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4908 
  4909 * searchable theorem database (see the section "Retrieving theorems" on
  4910 page 8 of the Reference Manual);
  4911 
  4912 * new examples, including Grabczewski's monumental case study of the
  4913 Axiom of Choice;
  4914 
  4915 * The previous version of HOL renamed to Old_HOL;
  4916 
  4917 * The new version of HOL (previously called CHOL) uses a curried syntax
  4918 for functions.  Application looks like f a b instead of f(a,b);
  4919 
  4920 * Mutually recursive inductive definitions finally work in HOL;
  4921 
  4922 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4923 translates to the operator "split";
  4924 
  4925 
  4926 
  4927 New in Isabelle94-3
  4928 -------------------
  4929 
  4930 * new infix operator, addss, allowing the classical reasoner to
  4931 perform simplification at each step of its search.  Example:
  4932         fast_tac (cs addss ss)
  4933 
  4934 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4935 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4936 look like (a,b) instead of <a,b>;
  4937 
  4938 * PLEASE NOTE: CHOL will eventually replace HOL!
  4939 
  4940 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4941 It translates to the operator "split".  A new theory of integers is available;
  4942 
  4943 * In ZF, integer numerals now denote two's-complement binary integers.
  4944 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4945 
  4946 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4947 of the Axiom of Choice;
  4948 
  4949 
  4950 
  4951 New in Isabelle94-2
  4952 -------------------
  4953 
  4954 * Significantly faster resolution;
  4955 
  4956 * the different sections in a .thy file can now be mixed and repeated
  4957 freely;
  4958 
  4959 * Database of theorems for FOL, HOL and ZF.  New
  4960 commands including qed, qed_goal and bind_thm store theorems in the database.
  4961 
  4962 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4963 a given theory (thms_of), or find out what theory a theorem was proved in
  4964 (theory_of_thm);
  4965 
  4966 * Bugs fixed in the inductive definition and datatype packages;
  4967 
  4968 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4969 and HOL_dup_cs obsolete;
  4970 
  4971 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4972 have been removed;
  4973 
  4974 * Simpler definition of function space in ZF;
  4975 
  4976 * new results about cardinal and ordinal arithmetic in ZF;
  4977 
  4978 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4979 types;
  4980 
  4981 
  4982 $Id$