NEWS
author haftmann
Fri Jul 20 14:28:25 2007 +0200 (2007-07-20)
changeset 23881 851c74f1bb69
parent 23850 f1434532a562
child 23888 babe337cce2d
permissions -rw-r--r--
moved class ord from Orderings.thy to HOL.thy
     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 * Legacy goal package: reduced interface to the bare minimum required
    28 to keep existing proof scripts running.  Most other user-level
    29 functions are now part of the OldGoals structure, which is *not* open
    30 by default (consider isatool expandshort before open OldGoals).
    31 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    32 these tend to cause confusion about the actual goal (!) context being
    33 used here, which is not necessarily the same as the_context().
    34 
    35 * Command 'find_theorems': supports "*" wild-card in "name:"
    36 criterion; "with_dups" option.  Certain ProofGeneral versions might
    37 support a specific search form (see ProofGeneral/CHANGES).
    38 
    39 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    40 by default, which means that "prems" (and also "fixed variables") are
    41 suppressed from proof state output.  Note that the ProofGeneral
    42 settings mechanism allows to change and save options persistently, but
    43 older versions of Isabelle will fail to start up if a negative prems
    44 limit is imposed.
    45 
    46 * Local theory targets may be specified by non-nested blocks of
    47 ``context/locale/class ... begin'' followed by ``end''.  The body may
    48 contain definitions, theorems etc., including any derived mechanism
    49 that has been implemented on top of these primitives.  This concept
    50 generalizes the existing ``theorem (in ...)'' towards more versatility
    51 and scalability.
    52 
    53 * Proof General interface: proper undo of final 'end' command;
    54 discontinued Isabelle/classic mode (ML proof scripts).
    55 
    56 
    57 *** Document preparation ***
    58 
    59 * Added antiquotation @{theory name} which prints the given name,
    60 after checking that it refers to a valid ancestor theory in the
    61 current context.
    62 
    63 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    64 check the given source text as ML type/structure, printing verbatim.
    65 
    66 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    67 "c args == rhs" given in the current context.  (Any number of
    68 arguments may be given on the LHS.)
    69 
    70 
    71 
    72 *** Pure ***
    73 
    74 * code generator: consts in 'consts_code' Isar commands are now referred
    75   to by usual term syntax (including optional type annotations).
    76 
    77 * code generator: 
    78   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    79     explicitly to the table of defining equations
    80   - primitive definitions are not used as defining equations by default any longer
    81   - defining equations are now definitly restricted to meta "==" and object
    82         equality "="
    83   - HOL theories have been adopted accordingly
    84 
    85 * class_package.ML offers a combination of axclasses and locales to
    86 achieve Haskell-like type classes in Isabelle.  See
    87 HOL/ex/Classpackage.thy for examples.
    88 
    89 * Yet another code generator framework allows to generate executable
    90 code for ML and Haskell (including "class"es).  A short usage sketch:
    91 
    92     internal compilation:
    93         code_gen <list of constants (term syntax)> in SML
    94     writing SML code to a file:
    95         code_gen <list of constants (term syntax)> in SML <filename>
    96     writing OCaml code to a file:
    97         code_gen <list of constants (term syntax)> in OCaml <filename>
    98     writing Haskell code to a bunch of files:
    99         code_gen <list of constants (term syntax)> in Haskell <filename>
   100 
   101 Reasonable default setup of framework in HOL/Main.
   102 
   103 Theorem attributs for selecting and transforming function equations theorems:
   104 
   105     [code fun]:        select a theorem as function equation for a specific constant
   106     [code fun del]:    deselect a theorem as function equation for a specific constant
   107     [code inline]:     select an equation theorem for unfolding (inlining) in place
   108     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   109 
   110 User-defined serializations (target in {SML, OCaml, Haskell}):
   111 
   112     code_const <and-list of constants (term syntax)>
   113       {(target) <and-list of const target syntax>}+
   114 
   115     code_type <and-list of type constructors>
   116       {(target) <and-list of type target syntax>}+
   117 
   118     code_instance <and-list of instances>
   119       {(target)}+
   120         where instance ::= <type constructor> :: <class>
   121 
   122     code_class <and_list of classes>
   123       {(target) <and-list of class target syntax>}+
   124         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   125 
   126 code_instance and code_class only apply to target Haskell.
   127 
   128 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   129 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   130 
   131 * Command 'no_translations' removes translation rules from theory
   132 syntax.
   133 
   134 * Overloaded definitions are now actually checked for acyclic
   135 dependencies.  The overloading scheme is slightly more general than
   136 that of Haskell98, although Isabelle does not demand an exact
   137 correspondence to type class and instance declarations.
   138 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   139 exotic versions of overloading -- at the discretion of the user!
   140 
   141 Polymorphic constants are represented via type arguments, i.e. the
   142 instantiation that matches an instance against the most general
   143 declaration given in the signature.  For example, with the declaration
   144 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   145 as c(nat).  Overloading is essentially simultaneous structural
   146 recursion over such type arguments.  Incomplete specification patterns
   147 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   148 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   149 Command 'print_theory' outputs the normalized system of recursive
   150 equations, see section "definitions".
   151 
   152 * Isar: method "assumption" (and implicit closing of subproofs) now
   153 takes simple non-atomic goal assumptions into account: after applying
   154 an assumption as a rule the resulting subgoals are solved by atomic
   155 assumption steps.  This is particularly useful to finish 'obtain'
   156 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   157 without referring to the original premise "!!x. P x ==> thesis" in the
   158 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   159 more permissive.
   160 
   161 * Isar: implicit use of prems from the Isar proof context is
   162 considered a legacy feature.  Common applications like ``have A .''
   163 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   164 referencing facts explicitly here improves readability and
   165 maintainability of proof texts.
   166 
   167 * Isar: improper proof element 'guess' is like 'obtain', but derives
   168 the obtained context from the course of reasoning!  For example:
   169 
   170   assume "EX x y. A x & B y"   -- "any previous fact"
   171   then guess x and y by clarify
   172 
   173 This technique is potentially adventurous, depending on the facts and
   174 proof tools being involved here.
   175 
   176 * Isar: known facts from the proof context may be specified as literal
   177 propositions, using ASCII back-quote syntax.  This works wherever
   178 named facts used to be allowed so far, in proof commands, proof
   179 methods, attributes etc.  Literal facts are retrieved from the context
   180 according to unification of type and term parameters.  For example,
   181 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   182 theorems in the current context, then these are valid literal facts:
   183 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   184 
   185 There is also a proof method "fact" which does the same composition
   186 for explicit goal states, e.g. the following proof texts coincide with
   187 certain special cases of literal facts:
   188 
   189   have "A" by fact                 ==  note `A`
   190   have "A ==> B" by fact           ==  note `A ==> B`
   191   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   192   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   193 
   194 * Isar: ":" (colon) is no longer a symbolic identifier character in
   195 outer syntax.  Thus symbolic identifiers may be used without
   196 additional white space in declarations like this: ``assume *: A''.
   197 
   198 * Isar: 'print_facts' prints all local facts of the current context,
   199 both named and unnamed ones.
   200 
   201 * Isar: 'def' now admits simultaneous definitions, e.g.:
   202 
   203   def x == "t" and y == "u"
   204 
   205 * Isar: added command 'unfolding', which is structurally similar to
   206 'using', but affects both the goal state and facts by unfolding given
   207 rewrite rules.  Thus many occurrences of the 'unfold' method or
   208 'unfolded' attribute may be replaced by first-class proof text.
   209 
   210 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   211 and command 'unfolding' now all support object-level equalities
   212 (potentially conditional).  The underlying notion of rewrite rule is
   213 analogous to the 'rule_format' attribute, but *not* that of the
   214 Simplifier (which is usually more generous).
   215 
   216 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   217 method expression within a sandbox consisting of the first N
   218 sub-goals, which need to exist.  For example, ``simp_all [3]''
   219 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   220 simplifies all new goals that emerge from applying rule foo to the
   221 originally first one.
   222 
   223 * Isar: schematic goals are no longer restricted to higher-order
   224 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   225 expected.
   226 
   227 * Isar: the conclusion of a long theorem statement is now either
   228 'shows' (a simultaneous conjunction, as before), or 'obtains'
   229 (essentially a disjunction of cases with local parameters and
   230 assumptions).  The latter allows to express general elimination rules
   231 adequately; in this notation common elimination rules look like this:
   232 
   233   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   234     assumes "EX x. P x"
   235     obtains x where "P x"
   236 
   237   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   238     assumes "A & B"
   239     obtains A and B
   240 
   241   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   242     assumes "A | B"
   243     obtains
   244       A
   245     | B
   246 
   247 The subsequent classical rules even refer to the formal "thesis"
   248 explicitly:
   249 
   250   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   251     obtains "~ thesis"
   252 
   253   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   254     obtains "thesis ==> something"
   255 
   256 The actual proof of an 'obtains' statement is analogous to that of the
   257 Isar proof element 'obtain', only that there may be several cases.
   258 Optional case names may be specified in parentheses; these will be
   259 available both in the present proof and as annotations in the
   260 resulting rule, for later use with the 'cases' method (cf. attribute
   261 case_names).
   262 
   263 * Isar: the assumptions of a long theorem statement are available as
   264 "assms" fact in the proof context.  This is more appropriate than the
   265 (historical) "prems", which refers to all assumptions of the current
   266 context, including those from the target locale, proof body etc.
   267 
   268 * Isar: 'print_statement' prints theorems from the current theory or
   269 proof context in long statement form, according to the syntax of a
   270 top-level lemma.
   271 
   272 * Isar: 'obtain' takes an optional case name for the local context
   273 introduction rule (default "that").
   274 
   275 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   276 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   277 to occur.
   278 
   279 * Pure: syntax "CONST name" produces a fully internalized constant
   280 according to the current context.  This is particularly useful for
   281 syntax translations that should refer to internal constant
   282 representations independently of name spaces.
   283 
   284 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   285 instead of "FOO ". This allows multiple binder declarations to coexist
   286 in the same context.  INCOMPATIBILITY.
   287 
   288 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   289 primitive that also works in a locale context (both for constants and
   290 fixed variables).  Type declaration and internal syntactic
   291 representation of given constants retrieved from the context.
   292 
   293 * Isar/locales: new derived specification elements 'axiomatization',
   294 'definition', 'abbreviation', which support type-inference, admit
   295 object-level specifications (equality, equivalence).  See also the
   296 isar-ref manual.  Examples:
   297 
   298   axiomatization
   299     eq  (infix "===" 50) where
   300     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   301 
   302   definition "f x y = x + y + 1"
   303   definition g where "g x = f x x"
   304 
   305   abbreviation
   306     neq  (infix "=!=" 50) where
   307     "x =!= y == ~ (x === y)"
   308 
   309 These specifications may be also used in a locale context.  Then the
   310 constants being introduced depend on certain fixed parameters, and the
   311 constant name is qualified by the locale base name.  An internal
   312 abbreviation takes care for convenient input and output, making the
   313 parameters implicit and using the original short name.  See also
   314 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   315 entities from a monomorphic theory.
   316 
   317 Presently, abbreviations are only available 'in' a target locale, but
   318 not inherited by general import expressions.  Also note that
   319 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   320 'translations' in common applications.
   321 
   322 Concrete syntax is attached to specified constants in internal form,
   323 independently of name spaces.  The parse tree representation is
   324 slightly different -- use 'notation' instead of raw 'syntax', and
   325 'translations' with explicit "CONST" markup to accommodate this.
   326 
   327 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   328 the current context.  Print mode "no_abbrevs" prevents inversion of
   329 abbreviations on output.
   330 
   331 * Isar/locales: improved parameter handling:
   332 - use of locales "var" and "struct" no longer necessary;
   333 - parameter renamings are no longer required to be injective.
   334   This enables, for example, to define a locale for endomorphisms thus:
   335   locale endom = homom mult mult h.
   336 
   337 * Isar/locales: changed the way locales with predicates are defined.
   338 Instead of accumulating the specification, the imported expression is
   339 now an interpretation.  INCOMPATIBILITY: different normal form of
   340 locale expressions.  In particular, in interpretations of locales with
   341 predicates, goals repesenting already interpreted fragments are not
   342 removed automatically.  Use methods `intro_locales' and
   343 `unfold_locales'; see below.
   344 
   345 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   346 provide backward reasoning on locales predicates.  The methods are
   347 aware of interpretations and discharge corresponding goals.
   348 `intro_locales' is less aggressive then `unfold_locales' and does not
   349 unfold predicates to assumptions.
   350 
   351 * Isar/locales: the order in which locale fragments are accumulated
   352 has changed.  This enables to override declarations from fragments due
   353 to interpretations -- for example, unwanted simp rules.
   354 
   355 * Provers/induct: improved internal context management to support
   356 local fixes and defines on-the-fly.  Thus explicit meta-level
   357 connectives !! and ==> are rarely required anymore in inductive goals
   358 (using object-logic connectives for this purpose has been long
   359 obsolete anyway).  The subsequent proof patterns illustrate advanced
   360 techniques of natural induction; general datatypes and inductive sets
   361 work analogously (see also src/HOL/Lambda for realistic examples).
   362 
   363 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   364 parameters:
   365 
   366   lemma
   367     fixes n :: nat and x :: 'a
   368     assumes a: "A n x"
   369     shows "P n x"
   370     using a                     -- {* make induct insert fact a *}
   371   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   372     case 0
   373     show ?case sorry
   374   next
   375     case (Suc n)
   376     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   377     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   378     show ?case sorry
   379   qed
   380 
   381 (2) This is how to perform induction over ``expressions of a certain
   382 form'', using a locally defined inductive parameter n == "a x"
   383 together with strengthening (the latter is usually required to get
   384 sufficiently flexible induction hypotheses):
   385 
   386   lemma
   387     fixes a :: "'a => nat"
   388     assumes a: "A (a x)"
   389     shows "P (a x)"
   390     using a
   391   proof (induct n == "a x" arbitrary: x)
   392     ...
   393 
   394 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   395 particular technique.
   396 
   397 (3) This is how to perform existential reasoning ('obtains' or
   398 'obtain') by induction, while avoiding explicit object-logic
   399 encodings:
   400 
   401   lemma
   402     fixes n :: nat
   403     obtains x :: 'a where "P n x" and "Q n x"
   404   proof (induct n arbitrary: thesis)
   405     case 0
   406     obtain x where "P 0 x" and "Q 0 x" sorry
   407     then show thesis by (rule 0)
   408   next
   409     case (Suc n)
   410     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   411     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   412     then show thesis by (rule Suc.prems)
   413   qed
   414 
   415 Here the 'arbitrary: thesis' specification essentially modifies the
   416 scope of the formal thesis parameter, in order to the get the whole
   417 existence statement through the induction as expected.
   418 
   419 * Provers/induct: mutual induction rules are now specified as a list
   420 of rule sharing the same induction cases.  HOL packages usually
   421 provide foo_bar.inducts for mutually defined items foo and bar
   422 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   423 specify mutual induction rules differently, i.e. like this:
   424 
   425   (induct rule: foo_bar.inducts)
   426   (induct set: foo bar)
   427   (induct type: foo bar)
   428 
   429 The ML function ProjectRule.projections turns old-style rules into the
   430 new format.
   431 
   432 * Provers/induct: improved handling of simultaneous goals.  Instead of
   433 introducing object-level conjunction, the statement is now split into
   434 several conclusions, while the corresponding symbolic cases are
   435 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   436 explicitly.  For example:
   437 
   438   lemma
   439     fixes n :: nat
   440     shows "P n" and "Q n"
   441   proof (induct n)
   442     case 0 case 1
   443     show "P 0" sorry
   444   next
   445     case 0 case 2
   446     show "Q 0" sorry
   447   next
   448     case (Suc n) case 1
   449     note `P n` and `Q n`
   450     show "P (Suc n)" sorry
   451   next
   452     case (Suc n) case 2
   453     note `P n` and `Q n`
   454     show "Q (Suc n)" sorry
   455   qed
   456 
   457 The split into subcases may be deferred as follows -- this is
   458 particularly relevant for goal statements with local premises.
   459 
   460   lemma
   461     fixes n :: nat
   462     shows "A n ==> P n" and "B n ==> Q n"
   463   proof (induct n)
   464     case 0
   465     {
   466       case 1
   467       note `A 0`
   468       show "P 0" sorry
   469     next
   470       case 2
   471       note `B 0`
   472       show "Q 0" sorry
   473     }
   474   next
   475     case (Suc n)
   476     note `A n ==> P n` and `B n ==> Q n`
   477     {
   478       case 1
   479       note `A (Suc n)`
   480       show "P (Suc n)" sorry
   481     next
   482       case 2
   483       note `B (Suc n)`
   484       show "Q (Suc n)" sorry
   485     }
   486   qed
   487 
   488 If simultaneous goals are to be used with mutual rules, the statement
   489 needs to be structured carefully as a two-level conjunction, using
   490 lists of propositions separated by 'and':
   491 
   492   lemma
   493     shows "a : A ==> P1 a"
   494           "a : A ==> P2 a"
   495       and "b : B ==> Q1 b"
   496           "b : B ==> Q2 b"
   497           "b : B ==> Q3 b"
   498   proof (induct set: A B)
   499 
   500 * Provers/induct: support coinduction as well.  See
   501 src/HOL/Library/Coinductive_List.thy for various examples.
   502 
   503 * Attribute "symmetric" produces result with standardized schematic
   504 variables (index 0).  Potential INCOMPATIBILITY.
   505 
   506 * Simplifier: by default the simplifier trace only shows top level
   507 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   508 default. Thus there is less danger of being flooded by the trace. The
   509 trace indicates where parts have been suppressed.
   510   
   511 * Provers/classical: removed obsolete classical version of elim_format
   512 attribute; classical elim/dest rules are now treated uniformly when
   513 manipulating the claset.
   514 
   515 * Provers/classical: stricter checks to ensure that supplied intro,
   516 dest and elim rules are well-formed; dest and elim rules must have at
   517 least one premise.
   518 
   519 * Provers/classical: attributes dest/elim/intro take an optional
   520 weight argument for the rule (just as the Pure versions).  Weights are
   521 ignored by automated tools, but determine the search order of single
   522 rule steps.
   523 
   524 * Syntax: input syntax now supports dummy variable binding "%_. b",
   525 where the body does not mention the bound variable.  Note that dummy
   526 patterns implicitly depend on their context of bounds, which makes
   527 "{_. _}" match any set comprehension as expected.  Potential
   528 INCOMPATIBILITY -- parse translations need to cope with syntactic
   529 constant "_idtdummy" in the binding position.
   530 
   531 * Syntax: removed obsolete syntactic constant "_K" and its associated
   532 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   533 for example "A -> B" => "Pi A (%_. B)".
   534 
   535 * Pure: 'class_deps' command visualizes the subclass relation, using
   536 the graph browser tool.
   537 
   538 * Pure: 'print_theory' now suppresses entities with internal name
   539 (trailing "_") by default; use '!' option for full details.
   540 
   541 
   542 *** HOL ***
   543 
   544 * Code generator library theories:
   545   * Pretty_Int represents HOL integers by big integer literals in target
   546     languages.
   547   * Pretty_Char represents HOL characters by character literals in target
   548     languages.
   549   * Pretty_Char_chr like Pretty_Char, but also offers treatment of character
   550     codes; includes Pretty_Int.
   551   * Executable_Set allows to generate code for finite sets using lists.
   552   * Executable_Rat implements rational numbers as triples (sign, enumerator,
   553     denominator).
   554   * Executable_Real implements a subset of real numbers, namly those
   555     representable by rational numbers.
   556   * Efficient_Nat implements natural numbers by integers, which in general will
   557     result in higher efficency; pattern matching with 0/Suc is eliminated;
   558     includes Pretty_Int.
   559   * ML_String provides an additional datatype ml_string; in the HOL default
   560     setup, strings in HOL are mapped to lists of HOL characters in SML; values
   561     of type ml_string are mapped to strings in SML.
   562   * ML_Int provides an additional datatype ml_int which is mapped to to SML
   563     built-in integers.
   564 
   565 * New package for inductive predicates
   566 
   567   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   568 
   569     inductive
   570       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   571       for z_1 :: U_1 and ... and z_n :: U_m
   572     where
   573       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   574     | ...
   575 
   576   rather than
   577 
   578     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   579 
   580     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   581     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   582 
   583     inductive "s z_1 ... z_m"
   584     intros
   585       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   586       ...
   587 
   588   For backward compatibility, there is a wrapper allowing inductive
   589   sets to be defined with the new package via
   590 
   591     inductive_set
   592       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   593       for z_1 :: U_1 and ... and z_n :: U_m
   594     where
   595       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   596     | ...
   597 
   598   or
   599 
   600     inductive_set
   601       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   602       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   603       for z_1 :: U_1 and ... and z_n :: U_m
   604     where
   605       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   606     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   607     | ...
   608 
   609   if the additional syntax "p ..." is required.
   610 
   611   Many examples can be found in the subdirectories Auth, Bali, Induct,
   612   or MicroJava.
   613 
   614   INCOMPATIBILITIES:
   615 
   616   - Since declaration and definition of inductive sets or predicates
   617     is no longer separated, abbreviations involving the newly introduced
   618     sets or predicates must be specified together with the introduction
   619     rules after the "where" keyword (see example above), rather than before
   620     the actual inductive definition.
   621 
   622   - The variables in induction and elimination rules are now quantified
   623     in the order of their occurrence in the introduction rules, rather than
   624     in alphabetical order. Since this may break some proofs, these proofs
   625     either have to be repaired, e.g. by reordering the variables
   626     a_i_1 ... a_i_{k_i} in Isar "case" statements of the form
   627 
   628       case (rule_i a_i_1 ... a_i_{k_i})
   629 
   630     or the old order of quantification has to be restored by explicitly adding
   631     meta-level quantifiers in the introduction rules, i.e.
   632 
   633       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   634 
   635   - The format of the elimination rules is now
   636 
   637       p z_1 ... z_m x_1 ... x_n ==>
   638         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   639         ==> ... ==> P
   640 
   641     for predicates and
   642 
   643       (x_1, ..., x_n) : s z_1 ... z_m ==>
   644         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
   645         ==> ... ==> P
   646 
   647     for sets rather than
   648 
   649       x : s z_1 ... z_m ==>
   650         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
   651         ==> ... ==> P
   652 
   653     This may require terms in goals to be expanded to n-tuples (e.g. using case_tac
   654     or simplification with the split_paired_all rule) before the above elimination
   655     rule is applicable.
   656 
   657   - The elimination or case analysis rules for (mutually) inductive sets or
   658     predicates are now called "p_1.cases" ... "p_k.cases". The list of rules
   659     "p_1_..._p_k.elims" is no longer available.
   660 
   661 * Method "metis" proves goals by applying the Metis general-purpose
   662 resolution prover.  Examples are in the directory MetisExamples.  See
   663 also http://gilith.com/software/metis/
   664   
   665 * Command 'sledgehammer' invokes external automatic theorem provers as
   666 background processes.  It generates calls to the "metis" method if
   667 successful. These can be pasted into the proof.  Users do not have to
   668 wait for the automatic provers to return.
   669 
   670 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   671   take their order into account, like in functional programming.
   672   Internally, this is translated into nested case-expressions; missing cases
   673   are added and mapped to the predefined constant "undefined". In complicated
   674   cases printing may no longer show the original input but the internal
   675   form. Lambda-abstractions allow the same form of pattern matching:
   676   "% pat1 => e1 | ..." is an abbreviation for
   677   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   678 
   679 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   680   is an abbreviation for "of_nat :: nat => int". The simplification rules
   681   for "of_nat" have been changed to work like "int" did previously.
   682   (potential INCOMPATIBILITY)
   683   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   684   - of_nat_diff and of_nat_mult are no longer default simp rules
   685 
   686 * Method "algebra" solves polynomial equations over (semi)rings using
   687   Groebner bases. The (semi)ring structure is defined by locales and
   688   the tool setup depends on that generic context. Installing the
   689   method for a specific type involves instantiating the locale and
   690   possibly adding declarations for computation on the coefficients.
   691   The method is already instantiated for natural numbers and for the
   692   axiomatic class of idoms with numerals.  See also the paper by
   693   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   694   underlying this architecture of context-aware proof-tools.
   695 
   696 * constant "List.op @" now named "List.append".  Use ML antiquotations
   697 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   698 possible incompatibilities when working on ML level.
   699 
   700 * Constant renames due to introduction of canonical name prefixing for
   701   class package:
   702 
   703     HOL.abs ~> HOL.minus_class.abs
   704     HOL.divide ~> HOL.divide_class.divide
   705     Nat.power ~> Nat.power_class.power
   706     Nat.size ~> Nat.size_class.size
   707     Numeral.number_of ~> Numeral.number_class.number_of
   708     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   709 
   710 * Rudimentary class target mechanism involves constant renames:
   711 
   712     Orderings.min ~> Orderings.ord_class.min
   713     Orderings.max ~> Orderings.ord_class.max
   714     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   715 
   716 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   717 
   718 * new constant "undefined" with axiom "undefined x = undefined"
   719 
   720 * new class "default" with associated constant "default"
   721 
   722 * new function listsum :: 'a list => 'a for arbitrary monoids.
   723   Special syntax: "SUM x <- xs. f x" (and latex variants)
   724 
   725 * new (input only) syntax for Haskell-like list comprehension, eg
   726   [(x,y). x <- xs, y <- ys, x ~= y]
   727   For details see List.thy.
   728 
   729 * The special syntax for function "filter" has changed from [x : xs. P] to
   730   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   731   and for uniformity. INCOMPATIBILITY
   732 
   733 * New lemma collection field_simps (an extension of ring_simps)
   734   for manipulating (in)equations involving division. Multiplies
   735   with all denominators that can be proved to be non-zero (in equations)
   736   or positive/negative (in inequations).
   737 
   738 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   739   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   740   Removed lemmas field_xyz in Ring_and_Field
   741   because they were subsumed by lemmas xyz.
   742 INCOMPATIBILITY.
   743 
   744 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   745   when generating code.
   746 
   747 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   748   when generating code.
   749 
   750 * Library/Commutative_Ring.thy: switched from recdef to function package;
   751   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   752 
   753 * Some steps towards more uniform lattice theory development in HOL.
   754 
   755     constants "meet" and "join" now named "inf" and "sup"
   756     constant "Meet" now named "Inf"
   757 
   758     classes "meet_semilorder" and "join_semilorder" now named
   759       "lower_semilattice" and "upper_semilattice"
   760     class "lorder" now named "lattice"
   761     class "comp_lat" now named "complete_lattice"
   762 
   763     Instantiation of lattice classes allows explicit definitions
   764     for "inf" and "sup" operations.
   765 
   766   INCOMPATIBILITY.  Theorem renames:
   767 
   768     meet_left_le            ~> inf_le1
   769     meet_right_le           ~> inf_le2
   770     join_left_le            ~> sup_ge1
   771     join_right_le           ~> sup_ge2
   772     meet_join_le            ~> inf_sup_ord
   773     le_meetI                ~> le_infI
   774     join_leI                ~> le_supI
   775     le_meet                 ~> le_inf_iff
   776     le_join                 ~> ge_sup_conv
   777     meet_idempotent         ~> inf_idem
   778     join_idempotent         ~> sup_idem
   779     meet_comm               ~> inf_commute
   780     join_comm               ~> sup_commute
   781     meet_leI1               ~> le_infI1
   782     meet_leI2               ~> le_infI2
   783     le_joinI1               ~> le_supI1
   784     le_joinI2               ~> le_supI2
   785     meet_assoc              ~> inf_assoc
   786     join_assoc              ~> sup_assoc
   787     meet_left_comm          ~> inf_left_commute
   788     meet_left_idempotent    ~> inf_left_idem
   789     join_left_comm          ~> sup_left_commute
   790     join_left_idempotent    ~> sup_left_idem
   791     meet_aci                ~> inf_aci
   792     join_aci                ~> sup_aci
   793     le_def_meet             ~> le_iff_inf
   794     le_def_join             ~> le_iff_sup
   795     join_absorp2            ~> sup_absorb2
   796     join_absorp1            ~> sup_absorb1
   797     meet_absorp1            ~> inf_absorb1
   798     meet_absorp2            ~> inf_absorb2
   799     meet_join_absorp        ~> inf_sup_absorb
   800     join_meet_absorp        ~> sup_inf_absorb
   801     distrib_join_le         ~> distrib_sup_le
   802     distrib_meet_le         ~> distrib_inf_le
   803 
   804     add_meet_distrib_left   ~> add_inf_distrib_left
   805     add_join_distrib_left   ~> add_sup_distrib_left
   806     is_join_neg_meet        ~> is_join_neg_inf
   807     is_meet_neg_join        ~> is_meet_neg_sup
   808     add_meet_distrib_right  ~> add_inf_distrib_right
   809     add_join_distrib_right  ~> add_sup_distrib_right
   810     add_meet_join_distribs  ~> add_sup_inf_distribs
   811     join_eq_neg_meet        ~> sup_eq_neg_inf
   812     meet_eq_neg_join        ~> inf_eq_neg_sup
   813     add_eq_meet_join        ~> add_eq_inf_sup
   814     meet_0_imp_0            ~> inf_0_imp_0
   815     join_0_imp_0            ~> sup_0_imp_0
   816     meet_0_eq_0             ~> inf_0_eq_0
   817     join_0_eq_0             ~> sup_0_eq_0
   818     neg_meet_eq_join        ~> neg_inf_eq_sup
   819     neg_join_eq_meet        ~> neg_sup_eq_inf
   820     join_eq_if              ~> sup_eq_if
   821 
   822     mono_meet               ~> mono_inf
   823     mono_join               ~> mono_sup
   824     meet_bool_eq            ~> inf_bool_eq
   825     join_bool_eq            ~> sup_bool_eq
   826     meet_fun_eq             ~> inf_fun_eq
   827     join_fun_eq             ~> sup_fun_eq
   828     meet_set_eq             ~> inf_set_eq
   829     join_set_eq             ~> sup_set_eq
   830     meet1_iff               ~> inf1_iff
   831     meet2_iff               ~> inf2_iff
   832     meet1I                  ~> inf1I
   833     meet2I                  ~> inf2I
   834     meet1D1                 ~> inf1D1
   835     meet2D1                 ~> inf2D1
   836     meet1D2                 ~> inf1D2
   837     meet2D2                 ~> inf2D2
   838     meet1E                  ~> inf1E
   839     meet2E                  ~> inf2E
   840     join1_iff               ~> sup1_iff
   841     join2_iff               ~> sup2_iff
   842     join1I1                 ~> sup1I1
   843     join2I1                 ~> sup2I1
   844     join1I1                 ~> sup1I1
   845     join2I2                 ~> sup1I2
   846     join1CI                 ~> sup1CI
   847     join2CI                 ~> sup2CI
   848     join1E                  ~> sup1E
   849     join2E                  ~> sup2E
   850 
   851     is_meet_Meet            ~> is_meet_Inf
   852     Meet_bool_def           ~> Inf_bool_def
   853     Meet_fun_def            ~> Inf_fun_def
   854     Meet_greatest           ~> Inf_greatest
   855     Meet_lower              ~> Inf_lower
   856     Meet_set_def            ~> Inf_set_def
   857 
   858     listsp_meetI            ~> listsp_infI
   859     listsp_meet_eq          ~> listsp_inf_eq
   860 
   861     meet_min                ~> inf_min
   862     join_max                ~> sup_max
   863 
   864 * Classes "order" and "linorder": facts "refl", "trans" and
   865 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   866 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   867 
   868 * Classes "order" and "linorder": 
   869 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   870 proofs changed.
   871 
   872 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   873 INCOMPATIBILITY.
   874 
   875 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   876 INCOMPATIBILITY.
   877 
   878 * Added syntactic class "size"; overloaded constant "size" now has
   879 type "'a::size ==> bool"
   880 
   881 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   882 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   883 
   884 * Added method "lexicographic_order" automatically synthesizes
   885 termination relations as lexicographic combinations of size measures
   886 -- 'function' package.
   887 
   888 * HOL/records: generalised field-update to take a function on the
   889 field rather than the new value: r(|A := x|) is translated to A_update
   890 (K x) r The K-combinator that is internally used is called K_record.
   891 INCOMPATIBILITY: Usage of the plain update functions has to be
   892 adapted.
   893  
   894 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   895 0 * x = 0, which are required for a semiring.  Richer structures do
   896 not inherit from semiring_0 anymore, because this property is a
   897 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   898 semiring_0, there is more to prove, but this is mostly trivial.
   899 
   900 * axclass "recpower" was generalized to arbitrary monoids, not just
   901 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   902 commutativity or a semiring property, add the corresponding classes.
   903 
   904 * Unified locale partial_order with class definition (cf. theory
   905 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   906 
   907 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   908 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   909 Isar level, use abbreviations instead.
   910 
   911 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   912 rarely occuring name references (e.g. ``List.op mem.simps'') require
   913 renaming (e.g. ``List.memberl.simps'').
   914 
   915 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   916 INCOMPATIBILITY.
   917 
   918 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   919 
   920 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   921 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   922 significant changes for setting up numeral syntax for types:
   923 
   924   - new constants Numeral.pred and Numeral.succ instead
   925       of former Numeral.bin_pred and Numeral.bin_succ.
   926   - Use integer operations instead of bin_add, bin_mult and so on.
   927   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   928   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   929 
   930 See HOL/Integ/IntArith.thy for an example setup.
   931 
   932 * New top level command 'normal_form' computes the normal form of a
   933 term that may contain free variables. For example ``normal_form
   934 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   935 suitable for heavy-duty computations because the functions are
   936 compiled to ML first.
   937 
   938 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   939 25 like -->); output depends on the "iff" print_mode, the default is
   940 "A = B" (with priority 50).
   941 
   942 * Renamed constants in HOL.thy and Orderings.thy:
   943     op +   ~> HOL.plus_class.plus
   944     op -   ~> HOL.minus_class.minus
   945     uminus ~> HOL.minus_class.uminus
   946     abs    ~> HOL.abs_class.abs
   947     op *   ~> HOL.times_class.times
   948     op <   ~> HOL.ord_class.less
   949     op <=  ~> HOL.ord_class.less_eq
   950 
   951 Adaptions may be required in the following cases:
   952 
   953 a) User-defined constants using any of the names "plus", "minus", "times",
   954 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   955 may go wrong.
   956 INCOMPATIBILITY: use more specific names.
   957 
   958 b) Variables named "plus", "minus", "times", "less", "less_eq"
   959 INCOMPATIBILITY: use more specific names.
   960 
   961 c) Permutative equations (e.g. "a + b = b + a")
   962 Since the change of names also changes the order of terms, permutative
   963 rewrite rules may get applied in a different order. Experience shows that
   964 this is rarely the case (only two adaptions in the whole Isabelle
   965 distribution).
   966 INCOMPATIBILITY: rewrite proofs
   967 
   968 d) ML code directly refering to constant names
   969 This in general only affects hand-written proof tactics, simprocs and so on.
   970 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   971 of const_name ML antiquotations.
   972 
   973 * Relations less (<) and less_eq (<=) are also available on type bool.
   974 Modified syntax to disallow nesting without explicit parentheses,
   975 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   976 
   977 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   978 
   979 * Relation composition operator "op O" now has precedence 75 and binds
   980 stronger than union and intersection. INCOMPATIBILITY.
   981 
   982 * The old set interval syntax "{m..n(}" (and relatives) has been
   983 removed.  Use "{m..<n}" (and relatives) instead.
   984 
   985 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   986 "t = s" to False (by simproc "neq_simproc").  For backward
   987 compatibility this can be disabled by ML "reset use_neq_simproc".
   988 
   989 * "m dvd n" where m and n are numbers is evaluated to True/False by
   990 simp.
   991 
   992 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   993 
   994 * Theorem setsum_mult renamed to setsum_right_distrib.
   995 
   996 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   997 ``rule'' method.
   998 
   999 * Reimplemented methods ``sat'' and ``satx'', with several
  1000 improvements: goals no longer need to be stated as "<prems> ==>
  1001 False", equivalences (i.e. "=" on type bool) are handled, variable
  1002 names of the form "lit_<n>" are no longer reserved, significant
  1003 speedup.
  1004 
  1005 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
  1006 zChaff is still supported as well.
  1007 
  1008 * 'inductive' and 'datatype': provide projections of mutual rules,
  1009 bundled as foo_bar.inducts;
  1010 
  1011 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1012 Library.
  1013 
  1014 * Library: moved theory Accessible_Part to main HOL.
  1015 
  1016 * Library: added theory Coinductive_List of potentially infinite lists
  1017 as greatest fixed-point.
  1018 
  1019 * Library: added theory AssocList which implements (finite) maps as
  1020 association lists.
  1021 
  1022 * Added proof method ``evaluation'' for efficiently solving a goal
  1023 (i.e. a boolean expression) by compiling it to ML. The goal is
  1024 "proved" (via an oracle) if it evaluates to True.
  1025 
  1026 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1027 also when invoked by the simplifier.  This results in the simplifier
  1028 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
  1029 fast_arith_split_limit to 0 to obtain the old behavior.
  1030 
  1031 * Support for hex (0x20) and binary (0b1001) numerals.
  1032 
  1033 * New method: reify eqs (t), where eqs are equations for an
  1034 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1035 parameter, computes a term s::'b and a list xs::'a list and proves the
  1036 theorem I xs s = t. This is also known as reification or quoting. The
  1037 resulting theorem is applied to the subgoal to substitute t with I xs
  1038 s.  If t is omitted, the subgoal itself is reified.
  1039 
  1040 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1041 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1042 where f is supposed to be a computable function (in the sense of code
  1043 generattion). The method uses reify to compute s and xs as above then
  1044 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1045 r and finally gets the theorem t = r, which is again applied to the
  1046 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
  1047 
  1048 * Reflection: Automatic reification now handels binding, an example
  1049 is available in HOL/ex/ReflectionEx.thy
  1050 
  1051 
  1052 *** HOL-Algebra ***
  1053 
  1054 * Formalisation of ideals and the quotient construction over rings.
  1055 
  1056 * Order and lattice theory no longer based on records.
  1057 INCOMPATIBILITY.
  1058 
  1059 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1060 greatest_closed.  INCOMPATIBILITY.
  1061 
  1062 * Method algebra is now set up via an attribute.  For examples see
  1063 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1064 of algebraic structures.
  1065 
  1066 * Renamed theory CRing to Ring.
  1067 
  1068 
  1069 *** HOL-Complex ***
  1070 
  1071 * Theory Real: new method ferrack implements quantifier elimination
  1072 for linear arithmetic over the reals. The quantifier elimination
  1073 feature is used only for decision, for compatibility with arith. This
  1074 means a goal is either solved or left unchanged, no simplification.
  1075 
  1076 * Hyperreal: Functions root and sqrt are now defined on negative real
  1077 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1078 Nonnegativity side conditions have been removed from many lemmas, so
  1079 that more subgoals may now be solved by simplification; potential
  1080 INCOMPATIBILITY.
  1081 
  1082 * Real: New axiomatic classes formalize real normed vector spaces and
  1083 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1084 and norm :: 'a => real.
  1085 
  1086 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
  1087 from reals into other types. The overloaded constant Reals :: 'a set
  1088 is now defined as range of_real; potential INCOMPATIBILITY.
  1089 
  1090 * Real: ML code generation is supported now and hence also quickcheck.
  1091 Reals are implemented as arbitrary precision rationals.
  1092 
  1093 * Hyperreal: Several constants that previously worked only for the
  1094 reals have been generalized, so they now work over arbitrary vector
  1095 spaces. Type annotations may need to be added in some cases; potential
  1096 INCOMPATIBILITY.
  1097 
  1098   Infinitesimal  :: ('a::real_normed_vector) star set
  1099   HFinite        :: ('a::real_normed_vector) star set
  1100   HInfinite      :: ('a::real_normed_vector) star set
  1101   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1102   monad          :: ('a::real_normed_vector) star => 'a star set
  1103   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1104   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1105   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1106   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1107   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1108   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1109   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1110   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1111   sgn            :: 'a::real_normed_vector => 'a
  1112   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1113 
  1114 * Complex: Some complex-specific constants are now abbreviations for
  1115 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1116 hnorm.  Other constants have been entirely removed in favor of the
  1117 polymorphic versions (INCOMPATIBILITY):
  1118 
  1119   approx        <-- capprox
  1120   HFinite       <-- CFinite
  1121   HInfinite     <-- CInfinite
  1122   Infinitesimal <-- CInfinitesimal
  1123   monad         <-- cmonad
  1124   galaxy        <-- cgalaxy
  1125   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1126   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1127   (ns)deriv     <-- (ns)cderiv
  1128 
  1129 
  1130 *** ML ***
  1131 
  1132 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1133 
  1134 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1135 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1136 init only required for impure data.  INCOMPATIBILITY: empty really
  1137 need to be empty (no dependencies on theory content!)
  1138 
  1139 * ML within Isar: antiquotations allow to embed statically-checked
  1140 formal entities in the source, referring to the context available at
  1141 compile-time.  For example:
  1142 
  1143 ML {* @{typ "'a => 'b"} *}
  1144 ML {* @{term "%x. x"} *}
  1145 ML {* @{prop "x == y"} *}
  1146 ML {* @{ctyp "'a => 'b"} *}
  1147 ML {* @{cterm "%x. x"} *}
  1148 ML {* @{cprop "x == y"} *}
  1149 ML {* @{thm asm_rl} *}
  1150 ML {* @{thms asm_rl} *}
  1151 ML {* @{const_name c} *}
  1152 ML {* @{const_syntax c} *}
  1153 ML {* @{context} *}
  1154 ML {* @{theory} *}
  1155 ML {* @{theory Pure} *}
  1156 ML {* @{simpset} *}
  1157 ML {* @{claset} *}
  1158 ML {* @{clasimpset} *}
  1159 
  1160 The same works for sources being ``used'' within an Isar context.
  1161 
  1162 * ML in Isar: improved error reporting; extra verbosity with
  1163 Toplevel.debug enabled.
  1164 
  1165 * Pure/library:
  1166 
  1167   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1168   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1169 
  1170 The semantics of "burrow" is: "take a function with *simulatanously*
  1171 transforms a list of value, and apply it *simulatanously* to a list of
  1172 list of values of the appropriate type". Compare this with "map" which
  1173 would *not* apply its argument function simulatanously but in
  1174 sequence; "fold_burrow" has an additional context.
  1175 
  1176 * Pure/library: functions map2 and fold2 with curried syntax for
  1177 simultanous mapping and folding:
  1178 
  1179     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1180     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1181 
  1182 * Pure/library: indexed lists - some functions in the Isabelle library
  1183 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1184 given more convenient names and signatures reminiscent of similar
  1185 functions for alists, tables, etc:
  1186 
  1187   val nth: 'a list -> int -> 'a 
  1188   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1189   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1190 
  1191 Note that fold_index starts counting at index 0, not 1 like foldln
  1192 used to.
  1193 
  1194 * Pure/library: added general ``divide_and_conquer'' combinator on
  1195 lists.
  1196 
  1197 * Pure/General/table.ML: the join operations now works via exceptions
  1198 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1199 admits slightly more efficient complex applications.
  1200 
  1201 * Pure: datatype Context.generic joins theory/Proof.context and
  1202 provides some facilities for code that works in either kind of
  1203 context, notably GenericDataFun for uniform theory and proof data.
  1204 
  1205 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1206 use Context.generic instead of just theory.
  1207 
  1208 * Pure: simplified internal attribute type, which is now always
  1209 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1210 vs. local (Proof.context) attributes have been discontinued, while
  1211 minimizing code duplication.  Thm.rule_attribute and
  1212 Thm.declaration_attribute build canonical attributes; see also
  1213 structure Context for further operations on Context.generic, notably
  1214 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1215 declarations and definitions.
  1216 
  1217 * Pure/kernel: consts certification ignores sort constraints given in
  1218 signature declarations.  (This information is not relevant to the
  1219 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1220 potential INCOMPATIBILITY.
  1221 
  1222 * Pure: axiomatic type classes are now purely definitional, with
  1223 explicit proofs of class axioms and super class relations performed
  1224 internally.  See Pure/axclass.ML for the main internal interfaces --
  1225 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1226 AxClass.axiomatize_class/classrel/arity supercede
  1227 Sign.add_classes/classrel/arities.
  1228 
  1229 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1230 global/local versions on theory vs. Proof.context have been
  1231 discontinued; Attrib.syntax and Method.syntax have been adapted
  1232 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1233 attributes, methods, etc.
  1234 
  1235 * Pure: several functions of signature "... -> theory -> theory * ..."
  1236 have been reoriented to "... -> theory -> ... * theory" in order to
  1237 allow natural usage in combination with the ||>, ||>>, |-> and
  1238 fold_map combinators.
  1239 
  1240 * Pure: official theorem names (closed derivations) and additional
  1241 comments (tags) are now strictly separate.  Name hints -- which are
  1242 maintained as tags -- may be attached any time without affecting the
  1243 derivation.
  1244 
  1245 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1246 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1247 achieve the old behaviour.
  1248 
  1249 * Pure: the "Goal" constant is now called "prop", supporting a
  1250 slightly more general idea of ``protecting'' meta-level rule
  1251 statements.
  1252 
  1253 * Pure: Logic.(un)varify only works in a global context, which is now
  1254 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1255 Logic.legacy_(un)varify as temporary workaround.
  1256 
  1257 * Pure: structure Name provides scalable operations for generating
  1258 internal variable names, notably Name.variants etc.  This replaces
  1259 some popular functions from term.ML:
  1260 
  1261   Term.variant		->  Name.variant
  1262   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1263   Term.invent_names	->  Name.invent_list
  1264 
  1265 Note that low-level renaming rarely occurs in new code -- operations
  1266 from structure Variable are used instead (see below).
  1267 
  1268 * Pure: structure Variable provides fundamental operations for proper
  1269 treatment of fixed/schematic variables in a context.  For example,
  1270 Variable.import introduces fixes for schematics of given facts and
  1271 Variable.export reverses the effect (up to renaming) -- this replaces
  1272 various freeze_thaw operations.
  1273 
  1274 * Pure: structure Goal provides simple interfaces for
  1275 init/conclude/finish and tactical prove operations (replacing former
  1276 Tactic.prove).  Goal.prove is the canonical way to prove results
  1277 within a given context; Goal.prove_global is a degraded version for
  1278 theory level goals, including a global Drule.standard.  Note that
  1279 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1280 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1281 in a locale context).
  1282 
  1283 * Isar: simplified treatment of user-level errors, using exception
  1284 ERROR of string uniformly.  Function error now merely raises ERROR,
  1285 without any side effect on output channels.  The Isar toplevel takes
  1286 care of proper display of ERROR exceptions.  ML code may use plain
  1287 handle/can/try; cat_error may be used to concatenate errors like this:
  1288 
  1289   ... handle ERROR msg => cat_error msg "..."
  1290 
  1291 Toplevel ML code (run directly or through the Isar toplevel) may be
  1292 embedded into the Isar toplevel with exception display/debug like
  1293 this:
  1294 
  1295   Isar.toplevel (fn () => ...)
  1296 
  1297 INCOMPATIBILITY, removed special transform_error facilities, removed
  1298 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1299 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1300 -- use plain ERROR instead.
  1301 
  1302 * Isar: theory setup now has type (theory -> theory), instead of a
  1303 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1304 
  1305 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1306 subject to ProofContext.debug/verbose flags.
  1307 
  1308 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1309 theory before entering a proof state.  Transactions now always see a
  1310 quasi-functional intermediate checkpoint, both in interactive and
  1311 batch mode.
  1312 
  1313 * Simplifier: the simpset of a running simplification process now
  1314 contains a proof context (cf. Simplifier.the_context), which is the
  1315 very context that the initial simpset has been retrieved from (by
  1316 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1317 (solver, looper etc.) may depend on arbitrary proof data.
  1318 
  1319 * Simplifier.inherit_context inherits the proof context (plus the
  1320 local bounds) of the current simplification process; any simproc
  1321 etc. that calls the Simplifier recursively should do this!  Removed
  1322 former Simplifier.inherit_bounds, which is already included here --
  1323 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1324 specify an explicit context using Simplifier.context/theory_context.
  1325 
  1326 * Simplifier/Classical Reasoner: more abstract interfaces
  1327 change_simpset/claset for modifying the simpset/claset reference of a
  1328 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1329 INCOMPATIBILITY.
  1330 
  1331 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1332 "Trueprop" etc.
  1333 
  1334 
  1335 *** System ***
  1336 
  1337 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1338 locations -- now includes the Isabelle version identifier as well.
  1339 This simplifies use of multiple Isabelle installations.
  1340 
  1341 * isabelle-process: option -S (secure mode) disables some critical
  1342 operations, notably runtime compilation and evaluation of ML source
  1343 code.
  1344 
  1345 
  1346 New in Isabelle2005 (October 2005)
  1347 ----------------------------------
  1348 
  1349 *** General ***
  1350 
  1351 * Theory headers: the new header syntax for Isar theories is
  1352 
  1353   theory <name>
  1354   imports <theory1> ... <theoryN>
  1355   uses <file1> ... <fileM>
  1356   begin
  1357 
  1358 where the 'uses' part is optional.  The previous syntax
  1359 
  1360   theory <name> = <theory1> + ... + <theoryN>:
  1361 
  1362 will disappear in the next release.  Use isatool fixheaders to convert
  1363 existing theory files.  Note that there is no change in ancient
  1364 non-Isar theories now, but these will disappear soon.
  1365 
  1366 * Theory loader: parent theories can now also be referred to via
  1367 relative and absolute paths.
  1368 
  1369 * Command 'find_theorems' searches for a list of criteria instead of a
  1370 list of constants. Known criteria are: intro, elim, dest, name:string,
  1371 simp:term, and any term. Criteria can be preceded by '-' to select
  1372 theorems that do not match. Intro, elim, dest select theorems that
  1373 match the current goal, name:s selects theorems whose fully qualified
  1374 name contain s, and simp:term selects all simplification rules whose
  1375 lhs match term.  Any other term is interpreted as pattern and selects
  1376 all theorems matching the pattern. Available in ProofGeneral under
  1377 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1378 
  1379   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1380 
  1381 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1382 matching the current goal as introduction rule and not having "HOL."
  1383 in their name (i.e. not being defined in theory HOL).
  1384 
  1385 * Command 'thms_containing' has been discontinued in favour of
  1386 'find_theorems'; INCOMPATIBILITY.
  1387 
  1388 * Communication with Proof General is now 8bit clean, which means that
  1389 Unicode text in UTF-8 encoding may be used within theory texts (both
  1390 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1391 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1392 
  1393   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1394   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1395 
  1396 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1397 Classical Reasoner.  Typical big applications run around 2 times
  1398 faster.
  1399 
  1400 
  1401 *** Document preparation ***
  1402 
  1403 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1404 of raw sources.  Only those symbols that do not require additional
  1405 LaTeX packages (depending on comments in isabellesym.sty) are
  1406 displayed properly, everything else is left verbatim.  isatool display
  1407 and isatool print are used as front ends (these are subject to the
  1408 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1409 
  1410 * Command tags control specific markup of certain regions of text,
  1411 notably folding and hiding.  Predefined tags include "theory" (for
  1412 theory begin and end), "proof" for proof commands, and "ML" for
  1413 commands involving ML code; the additional tags "visible" and
  1414 "invisible" are unused by default.  Users may give explicit tag
  1415 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1416 interpretation of tags is determined by the LaTeX job during document
  1417 preparation: see option -V of isatool usedir, or options -n and -t of
  1418 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1419 \isadroptag.
  1420 
  1421 Several document versions may be produced at the same time via isatool
  1422 usedir (the generated index.html will link all of them).  Typical
  1423 specifications include ''-V document=theory,proof,ML'' to present
  1424 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1425 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1426 these parts without any formal replacement text.  The Isabelle site
  1427 default settings produce ''document'' and ''outline'' versions as
  1428 specified above.
  1429 
  1430 * Several new antiquotations:
  1431 
  1432   @{term_type term} prints a term with its type annotated;
  1433 
  1434   @{typeof term} prints the type of a term;
  1435 
  1436   @{const const} is the same as @{term const}, but checks that the
  1437   argument is a known logical constant;
  1438 
  1439   @{term_style style term} and @{thm_style style thm} print a term or
  1440   theorem applying a "style" to it
  1441 
  1442   @{ML text}
  1443 
  1444 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1445 definitions, equations, inequations etc., 'concl' printing only the
  1446 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1447 to print the specified premise.  TermStyle.add_style provides an ML
  1448 interface for introducing further styles.  See also the "LaTeX Sugar"
  1449 document practical applications.  The ML antiquotation prints
  1450 type-checked ML expressions verbatim.
  1451 
  1452 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1453 and 'text' support optional locale specification '(in loc)', which
  1454 specifies the default context for interpreting antiquotations.  For
  1455 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1456 
  1457 * Option 'locale=NAME' of antiquotations specifies an alternative
  1458 context interpreting the subsequent argument.  For example: @{thm
  1459 [locale=lattice] inf_assoc}.
  1460 
  1461 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1462 a proof context.
  1463 
  1464 * Proper output of antiquotations for theory commands involving a
  1465 proof context (such as 'locale' or 'theorem (in loc) ...').
  1466 
  1467 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1468 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1469 
  1470 * isatool usedir: new option -C (default true) controls whether option
  1471 -D should include a copy of the original document directory; -C false
  1472 prevents unwanted effects such as copying of administrative CVS data.
  1473 
  1474 
  1475 *** Pure ***
  1476 
  1477 * Considerably improved version of 'constdefs' command.  Now performs
  1478 automatic type-inference of declared constants; additional support for
  1479 local structure declarations (cf. locales and HOL records), see also
  1480 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1481 sequential dependencies of definitions within a single 'constdefs'
  1482 section; moreover, the declared name needs to be an identifier.  If
  1483 all fails, consider to fall back on 'consts' and 'defs' separately.
  1484 
  1485 * Improved indexed syntax and implicit structures.  First of all,
  1486 indexed syntax provides a notational device for subscripted
  1487 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1488 expressions.  Secondly, in a local context with structure
  1489 declarations, number indexes \<^sub>n or the empty index (default
  1490 number 1) refer to a certain fixed variable implicitly; option
  1491 show_structs controls printing of implicit structures.  Typical
  1492 applications of these concepts involve record types and locales.
  1493 
  1494 * New command 'no_syntax' removes grammar declarations (and
  1495 translations) resulting from the given syntax specification, which is
  1496 interpreted in the same manner as for the 'syntax' command.
  1497 
  1498 * 'Advanced' translation functions (parse_translation etc.) may depend
  1499 on the signature of the theory context being presently used for
  1500 parsing/printing, see also isar-ref manual.
  1501 
  1502 * Improved 'oracle' command provides a type-safe interface to turn an
  1503 ML expression of type theory -> T -> term into a primitive rule of
  1504 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1505 is already included here); see also FOL/ex/IffExample.thy;
  1506 INCOMPATIBILITY.
  1507 
  1508 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1509 before); "cI" is no longer bound, use "c.intro" instead.
  1510 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1511 axclasses vs. locales.
  1512 
  1513 * Improved internal renaming of symbolic identifiers -- attach primes
  1514 instead of base 26 numbers.
  1515 
  1516 * New flag show_question_marks controls printing of leading question
  1517 marks in schematic variable names.
  1518 
  1519 * In schematic variable names, *any* symbol following \<^isub> or
  1520 \<^isup> is now treated as part of the base name.  For example, the
  1521 following works without printing of awkward ".0" indexes:
  1522 
  1523   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1524     by simp
  1525 
  1526 * Inner syntax includes (*(*nested*) comments*).
  1527 
  1528 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1529 annotations as "(00...)".
  1530 
  1531 * Clear separation of logical types and nonterminals, where the latter
  1532 may only occur in 'syntax' specifications or type abbreviations.
  1533 Before that distinction was only partially implemented via type class
  1534 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1535 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1536 exotic syntax specifications may require further adaption
  1537 (e.g. Cube/Cube.thy).
  1538 
  1539 * Removed obsolete type class "logic", use the top sort {} instead.
  1540 Note that non-logical types should be declared as 'nonterminals'
  1541 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1542 specifications.
  1543 
  1544 * Attributes 'induct' and 'cases': type or set names may now be
  1545 locally fixed variables as well.
  1546 
  1547 * Simplifier: can now control the depth to which conditional rewriting
  1548 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1549 Limit.
  1550 
  1551 * Simplifier: simplification procedures may now take the current
  1552 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1553 interface), which is very useful for calling the Simplifier
  1554 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1555 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1556 low-level mk_simproc no longer applies Logic.varify internally, to
  1557 allow for use in a context of fixed variables.
  1558 
  1559 * thin_tac now works even if the assumption being deleted contains !!
  1560 or ==>.  More generally, erule now works even if the major premise of
  1561 the elimination rule contains !! or ==>.
  1562 
  1563 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1564 
  1565 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1566 from Pure, which contains all common declarations already.  Both
  1567 theories are defined via plain Isabelle/Isar .thy files.
  1568 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1569 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1570 use isatool fixcpure to adapt your theory and ML sources.
  1571 
  1572 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1573 selections of theorems in named facts via index ranges.
  1574 
  1575 * 'print_theorems': in theory mode, really print the difference
  1576 wrt. the last state (works for interactive theory development only),
  1577 in proof mode print all local facts (cf. 'print_facts');
  1578 
  1579 * 'hide': option '(open)' hides only base names.
  1580 
  1581 * More efficient treatment of intermediate checkpoints in interactive
  1582 theory development.
  1583 
  1584 * Code generator is now invoked via code_module (incremental code
  1585 generation) and code_library (modular code generation, ML structures
  1586 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1587 must be quoted when used as identifiers.
  1588 
  1589 * New 'value' command for reading, evaluating and printing terms using
  1590 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1591 quoted when used as identifier.
  1592 
  1593 
  1594 *** Locales ***
  1595 
  1596 * New commands for the interpretation of locale expressions in
  1597 theories (1), locales (2) and proof contexts (3).  These generate
  1598 proof obligations from the expression specification.  After the
  1599 obligations have been discharged, theorems of the expression are added
  1600 to the theory, target locale or proof context.  The synopsis of the
  1601 commands is a follows:
  1602 
  1603   (1) interpretation expr inst
  1604   (2) interpretation target < expr
  1605   (3) interpret expr inst
  1606 
  1607 Interpretation in theories and proof contexts require a parameter
  1608 instantiation of terms from the current context.  This is applied to
  1609 specifications and theorems of the interpreted expression.
  1610 Interpretation in locales only permits parameter renaming through the
  1611 locale expression.  Interpretation is smart in that interpretations
  1612 that are active already do not occur in proof obligations, neither are
  1613 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1614 inspect active interpretations of a particular locale.  For details,
  1615 see the Isar Reference manual.  Examples can be found in
  1616 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1617 
  1618 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1619 'interpret' instead.
  1620 
  1621 * New context element 'constrains' for adding type constraints to
  1622 parameters.
  1623 
  1624 * Context expressions: renaming of parameters with syntax
  1625 redeclaration.
  1626 
  1627 * Locale declaration: 'includes' disallowed.
  1628 
  1629 * Proper static binding of attribute syntax -- i.e. types / terms /
  1630 facts mentioned as arguments are always those of the locale definition
  1631 context, independently of the context of later invocations.  Moreover,
  1632 locale operations (renaming and type / term instantiation) are applied
  1633 to attribute arguments as expected.
  1634 
  1635 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1636 actual attributes; rare situations may require Attrib.attribute to
  1637 embed those attributes into Attrib.src that lack concrete syntax.
  1638 Attribute implementations need to cooperate properly with the static
  1639 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1640 Attrib.XXX_thm etc. already do the right thing without further
  1641 intervention.  Only unusual applications -- such as "where" or "of"
  1642 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1643 on the context and the facts involved -- may have to assign parsed
  1644 values to argument tokens explicitly.
  1645 
  1646 * Changed parameter management in theorem generation for long goal
  1647 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1648 theorem statement in rare situations.
  1649 
  1650 * Locale inspection command 'print_locale' omits notes elements.  Use
  1651 'print_locale!' to have them included in the output.
  1652 
  1653 
  1654 *** Provers ***
  1655 
  1656 * Provers/hypsubst.ML: improved version of the subst method, for
  1657 single-step rewriting: it now works in bound variable contexts. New is
  1658 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1659 rewrite a different subterm than the original subst method, which is
  1660 still available as 'simplesubst'.
  1661 
  1662 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1663 and quasi orders.
  1664 
  1665 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1666 reflexive-transitive closure of relations.
  1667 
  1668 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1669 limit (previously hard-coded with a value of 20) user-definable.
  1670 
  1671 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1672 is peformed already.  Object-logics merely need to finish their
  1673 initial simpset configuration as before.  INCOMPATIBILITY.
  1674 
  1675 
  1676 *** HOL ***
  1677 
  1678 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1679 
  1680   syntax (epsilon)
  1681     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1682 
  1683 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1684 and x-symbol; use option '-m epsilon' to get it actually printed.
  1685 Moreover, the mathematically important symbolic identifier \<epsilon>
  1686 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1687 
  1688 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1689 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1690 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1691 support corresponding Isar calculations.
  1692 
  1693 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1694 instead of ":".
  1695 
  1696 * theory SetInterval: changed the syntax for open intervals:
  1697 
  1698   Old       New
  1699   {..n(}    {..<n}
  1700   {)n..}    {n<..}
  1701   {m..n(}   {m..<n}
  1702   {)m..n}   {m<..n}
  1703   {)m..n(}  {m<..<n}
  1704 
  1705 The old syntax is still supported but will disappear in the next
  1706 release.  For conversion use the following Emacs search and replace
  1707 patterns (these are not perfect but work quite well):
  1708 
  1709   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1710   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1711 
  1712 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1713 equalities in commutative rings; method 'algebra' provides a generic
  1714 interface.
  1715 
  1716 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1717 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1718 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1719 be a tuple pattern.
  1720 
  1721 Some new syntax forms are available:
  1722 
  1723   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1724   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1725   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1726   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1727 
  1728 The latter form "\<Sum>x < k. e" used to be based on a separate
  1729 function "Summation", which has been discontinued.
  1730 
  1731 * theory Finite_Set: in structured induction proofs, the insert case
  1732 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1733 (insert F x)'.
  1734 
  1735 * The 'refute' command has been extended to support a much larger
  1736 fragment of HOL, including axiomatic type classes, constdefs and
  1737 typedefs, inductive datatypes and recursion.
  1738 
  1739 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1740 Requires zChaff with proof generation to be installed.  See
  1741 HOL/ex/SAT_Examples.thy for examples.
  1742 
  1743 * Datatype induction via method 'induct' now preserves the name of the
  1744 induction variable. For example, when proving P(xs::'a list) by
  1745 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1746 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1747 in unstructured proof scripts.
  1748 
  1749 * Reworked implementation of records.  Improved scalability for
  1750 records with many fields, avoiding performance problems for type
  1751 inference. Records are no longer composed of nested field types, but
  1752 of nested extension types. Therefore the record type only grows linear
  1753 in the number of extensions and not in the number of fields.  The
  1754 top-level (users) view on records is preserved.  Potential
  1755 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1756 old record representation. The type generated for a record is called
  1757 <record_name>_ext_type.
  1758 
  1759 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1760 proofs triggered by a record definition or a simproc (if
  1761 quick_and_dirty is enabled).  Definitions of large records can take
  1762 quite long.
  1763 
  1764 New simproc record_upd_simproc for simplification of multiple record
  1765 updates enabled by default.  Moreover, trivial updates are also
  1766 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1767 occasionally, since simplification is more powerful by default.
  1768 
  1769 * typedef: proper support for polymorphic sets, which contain extra
  1770 type-variables in the term.
  1771 
  1772 * Simplifier: automatically reasons about transitivity chains
  1773 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1774 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1775 old proofs break occasionally as simplification may now solve more
  1776 goals than previously.
  1777 
  1778 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1779 present.  Works for all partial orders (class "order"), in particular
  1780 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1781 just like y <= x.
  1782 
  1783 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1784 bound variable or a constant then the let is unfolded.  Otherwise
  1785 first a is simplified to b, and then f b is simplified to g. If
  1786 possible we abstract b from g arriving at "let x = b in h x",
  1787 otherwise we unfold the let and arrive at g.  The simproc can be
  1788 enabled/disabled by the reference use_let_simproc.  Potential
  1789 INCOMPATIBILITY since simplification is more powerful by default.
  1790 
  1791 * Classical reasoning: the meson method now accepts theorems as arguments.
  1792 
  1793 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1794 jobs to provide advice on the provability of subgoals.
  1795 
  1796 * Theory OrderedGroup and Ring_and_Field: various additions and
  1797 improvements to faciliate calculations involving equalities and
  1798 inequalities.
  1799 
  1800 The following theorems have been eliminated or modified
  1801 (INCOMPATIBILITY):
  1802 
  1803   abs_eq             now named abs_of_nonneg
  1804   abs_of_ge_0        now named abs_of_nonneg
  1805   abs_minus_eq       now named abs_of_nonpos
  1806   imp_abs_id         now named abs_of_nonneg
  1807   imp_abs_neg_id     now named abs_of_nonpos
  1808   mult_pos           now named mult_pos_pos
  1809   mult_pos_le        now named mult_nonneg_nonneg
  1810   mult_pos_neg_le    now named mult_nonneg_nonpos
  1811   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1812   mult_neg           now named mult_neg_neg
  1813   mult_neg_le        now named mult_nonpos_nonpos
  1814 
  1815 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1816      
  1817      zero_le_square
  1818      not_square_less_zero 
  1819 
  1820   The following lemmas have been deleted from Real/RealPow:
  1821   
  1822      realpow_zero_zero
  1823      realpow_two
  1824      realpow_less
  1825      zero_le_power
  1826      realpow_two_le
  1827      abs_realpow_two
  1828      realpow_two_abs     
  1829 
  1830 * Theory Parity: added rules for simplifying exponents.
  1831 
  1832 * Theory List:
  1833 
  1834 The following theorems have been eliminated or modified
  1835 (INCOMPATIBILITY):
  1836 
  1837   list_all_Nil       now named list_all.simps(1)
  1838   list_all_Cons      now named list_all.simps(2)
  1839   list_all_conv      now named list_all_iff
  1840   set_mem_eq         now named mem_iff
  1841 
  1842 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1843 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1844 
  1845 
  1846 *** HOL-Complex ***
  1847 
  1848 * Theory RealDef: better support for embedding natural numbers and
  1849 integers in the reals.
  1850 
  1851 The following theorems have been eliminated or modified
  1852 (INCOMPATIBILITY):
  1853 
  1854   exp_ge_add_one_self  now requires no hypotheses
  1855   real_of_int_add      reversed direction of equality (use [symmetric])
  1856   real_of_int_minus    reversed direction of equality (use [symmetric])
  1857   real_of_int_diff     reversed direction of equality (use [symmetric])
  1858   real_of_int_mult     reversed direction of equality (use [symmetric])
  1859 
  1860 * Theory RComplete: expanded support for floor and ceiling functions.
  1861 
  1862 * Theory Ln is new, with properties of the natural logarithm
  1863 
  1864 * Hyperreal: There is a new type constructor "star" for making
  1865 nonstandard types.  The old type names are now type synonyms:
  1866 
  1867   hypreal = real star
  1868   hypnat = nat star
  1869   hcomplex = complex star
  1870 
  1871 * Hyperreal: Many groups of similarly-defined constants have been
  1872 replaced by polymorphic versions (INCOMPATIBILITY):
  1873 
  1874   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1875 
  1876   starset      <-- starsetNat, starsetC
  1877   *s*          <-- *sNat*, *sc*
  1878   starset_n    <-- starsetNat_n, starsetC_n
  1879   *sn*         <-- *sNatn*, *scn*
  1880   InternalSets <-- InternalNatSets, InternalCSets
  1881 
  1882   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1883   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1884   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1885   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1886   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1887 
  1888 * Hyperreal: Many type-specific theorems have been removed in favor of
  1889 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1890 
  1891   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1892   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1893   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1894   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1895   right_minus <-- hypreal_add_minus
  1896   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1897   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1898   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1899   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1900   mult_1_right <-- hcomplex_mult_one_right
  1901   mult_zero_left <-- hcomplex_mult_zero_left
  1902   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1903   right_distrib <-- hypnat_add_mult_distrib2
  1904   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1905   right_inverse <-- hypreal_mult_inverse
  1906   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1907   order_refl <-- {hypreal,hypnat}_le_refl
  1908   order_trans <-- {hypreal,hypnat}_le_trans
  1909   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1910   order_less_le <-- {hypreal,hypnat}_less_le
  1911   linorder_linear <-- {hypreal,hypnat}_le_linear
  1912   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1913   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1914   add_nonneg_nonneg <-- hypreal_le_add_order
  1915 
  1916 * Hyperreal: Separate theorems having to do with type-specific
  1917 versions of constants have been merged into theorems that apply to the
  1918 new polymorphic constants (INCOMPATIBILITY):
  1919 
  1920   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1921   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1922   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1923   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1924   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1925   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1926   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1927   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1928   STAR_diff <-- {STAR,STARC}_diff
  1929   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1930     STARC_hcomplex_of_complex}_image_subset
  1931   starset_n_Un <-- starset{Nat,C}_n_Un
  1932   starset_n_Int <-- starset{Nat,C}_n_Int
  1933   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1934   starset_n_diff <-- starset{Nat,C}_n_diff
  1935   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1936   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1937   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1938   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1939   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1940   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1941   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1942   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1943   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1944   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1945   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1946   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1947   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1948   starfun_diff <-- starfun{C,RC,CR}_diff
  1949   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1950   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1951   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1952   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1953   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1954   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1955   starfun_Id <-- starfunC_Id
  1956   starfun_approx <-- starfun{Nat,CR}_approx
  1957   starfun_capprox <-- starfun{C,RC}_capprox
  1958   starfun_abs <-- starfunNat_rabs
  1959   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1960   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1961   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1962   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1963   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1964   starfun_add_approx <-- starfunCR_add_approx
  1965   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1966   starfun_divide <-- starfun{C,CR,RC}_divide
  1967   starfun_n <-- starfun{Nat,C}_n
  1968   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1969   starfun_n_add <-- starfun{Nat,C}_n_add
  1970   starfun_n_add_minus <-- starfunNat_n_add_minus
  1971   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1972   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1973   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1974 
  1975   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1976   star_n_minus <-- {hypreal,hcomplex}_minus
  1977   star_n_diff <-- {hypreal,hcomplex}_diff
  1978   star_n_mult <-- {hypreal,hcomplex}_mult
  1979   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1980   star_n_le <-- {hypreal,hypnat}_le
  1981   star_n_less <-- {hypreal,hypnat}_less
  1982   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1983   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1984   star_n_abs <-- hypreal_hrabs
  1985   star_n_divide <-- hcomplex_divide
  1986 
  1987   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1988   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1989   star_of_diff <-- hypreal_of_real_diff
  1990   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1991   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1992   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1993   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1994   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1995   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1996   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1997   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1998   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1999   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2000   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2001   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2002   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2003   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2004   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2005   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2006   star_of_power <-- hypreal_of_real_power
  2007   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2008 
  2009 * Hyperreal: new method "transfer" that implements the transfer
  2010 principle of nonstandard analysis. With a subgoal that mentions
  2011 nonstandard types like "'a star", the command "apply transfer"
  2012 replaces it with an equivalent one that mentions only standard types.
  2013 To be successful, all free variables must have standard types; non-
  2014 standard variables must have explicit universal quantifiers.
  2015 
  2016 * Hyperreal: A theory of Taylor series.
  2017 
  2018 
  2019 *** HOLCF ***
  2020 
  2021 * Discontinued special version of 'constdefs' (which used to support
  2022 continuous functions) in favor of the general Pure one with full
  2023 type-inference.
  2024 
  2025 * New simplification procedure for solving continuity conditions; it
  2026 is much faster on terms with many nested lambda abstractions (cubic
  2027 instead of exponential time).
  2028 
  2029 * New syntax for domain package: selector names are now optional.
  2030 Parentheses should be omitted unless argument is lazy, for example:
  2031 
  2032   domain 'a stream = cons "'a" (lazy "'a stream")
  2033 
  2034 * New command 'fixrec' for defining recursive functions with pattern
  2035 matching; defining multiple functions with mutual recursion is also
  2036 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2037 sinr, or any data constructor defined by the domain package. The given
  2038 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2039 syntax and examples.
  2040 
  2041 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2042 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2043 but the proof obligation additionally includes an admissibility
  2044 requirement. The packages generate instances of class cpo or pcpo,
  2045 with continuity and strictness theorems for Rep and Abs.
  2046 
  2047 * HOLCF: Many theorems have been renamed according to a more standard naming
  2048 scheme (INCOMPATIBILITY):
  2049 
  2050   foo_inject:  "foo$x = foo$y ==> x = y"
  2051   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2052   foo_less:    "(foo$x << foo$y) = (x << y)"
  2053   foo_strict:  "foo$UU = UU"
  2054   foo_defined: "... ==> foo$x ~= UU"
  2055   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2056 
  2057 
  2058 *** ZF ***
  2059 
  2060 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2061 including the First Isomorphism Theorem (on quotienting by the kernel
  2062 of a homomorphism).
  2063 
  2064 * ZF/Simplifier: install second copy of type solver that actually
  2065 makes use of TC rules declared to Isar proof contexts (or locales);
  2066 the old version is still required for ML proof scripts.
  2067 
  2068 
  2069 *** Cube ***
  2070 
  2071 * Converted to Isar theory format; use locales instead of axiomatic
  2072 theories.
  2073 
  2074 
  2075 *** ML ***
  2076 
  2077 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2078 for ||>, ||>>, |>>,
  2079 
  2080 * Pure/library.ML no longer defines its own option datatype, but uses
  2081 that of the SML basis, which has constructors NONE and SOME instead of
  2082 None and Some, as well as exception Option.Option instead of OPTION.
  2083 The functions the, if_none, is_some, is_none have been adapted
  2084 accordingly, while Option.map replaces apsome.
  2085 
  2086 * Pure/library.ML: the exception LIST has been given up in favour of
  2087 the standard exceptions Empty and Subscript, as well as
  2088 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2089 superceded by the standard hd and tl functions etc.
  2090 
  2091 A number of basic list functions are no longer exported to the ML
  2092 toplevel, as they are variants of predefined functions.  The following
  2093 suggests how one can translate existing code:
  2094 
  2095     rev_append xs ys = List.revAppend (xs, ys)
  2096     nth_elem (i, xs) = List.nth (xs, i)
  2097     last_elem xs = List.last xs
  2098     flat xss = List.concat xss
  2099     seq fs = List.app fs
  2100     partition P xs = List.partition P xs
  2101     mapfilter f xs = List.mapPartial f xs
  2102 
  2103 * Pure/library.ML: several combinators for linear functional
  2104 transformations, notably reverse application and composition:
  2105 
  2106   x |> f                f #> g
  2107   (x, y) |-> f          f #-> g
  2108 
  2109 * Pure/library.ML: introduced/changed precedence of infix operators:
  2110 
  2111   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2112   infix 2 ?;
  2113   infix 3 o oo ooo oooo;
  2114   infix 4 ~~ upto downto;
  2115 
  2116 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2117 infix operators.
  2118 
  2119 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2120 fold_map support linear functional transformations and nesting.  For
  2121 example:
  2122 
  2123   fold f [x1, ..., xN] y =
  2124     y |> f x1 |> ... |> f xN
  2125 
  2126   (fold o fold) f [xs1, ..., xsN] y =
  2127     y |> fold f xs1 |> ... |> fold f xsN
  2128 
  2129   fold f [x1, ..., xN] =
  2130     f x1 #> ... #> f xN
  2131 
  2132   (fold o fold) f [xs1, ..., xsN] =
  2133     fold f xs1 #> ... #> fold f xsN
  2134 
  2135 * Pure/library.ML: the following selectors on type 'a option are
  2136 available:
  2137 
  2138   the:               'a option -> 'a  (*partial*)
  2139   these:             'a option -> 'a  where 'a = 'b list
  2140   the_default: 'a -> 'a option -> 'a
  2141   the_list:          'a option -> 'a list
  2142 
  2143 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2144 basic operations for association lists, following natural argument
  2145 order; moreover the explicit equality predicate passed here avoids
  2146 potentially expensive polymorphic runtime equality checks.
  2147 The old functions may be expressed as follows:
  2148 
  2149   assoc = uncurry (AList.lookup (op =))
  2150   assocs = these oo AList.lookup (op =)
  2151   overwrite = uncurry (AList.update (op =)) o swap
  2152 
  2153 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2154 
  2155   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2156   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2157 
  2158 replacing make_keylist and keyfilter (occassionally used)
  2159 Naive rewrites:
  2160 
  2161   make_keylist = AList.make
  2162   keyfilter = AList.find (op =)
  2163 
  2164 * eq_fst and eq_snd now take explicit equality parameter, thus
  2165   avoiding eqtypes. Naive rewrites:
  2166 
  2167     eq_fst = eq_fst (op =)
  2168     eq_snd = eq_snd (op =)
  2169 
  2170 * Removed deprecated apl and apr (rarely used).
  2171   Naive rewrites:
  2172 
  2173     apl (n, op) =>>= curry op n
  2174     apr (op, m) =>>= fn n => op (n, m)
  2175 
  2176 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2177 provides a reasonably efficient light-weight implementation of sets as
  2178 lists.
  2179 
  2180 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2181 few new operations; existing lookup and update are now curried to
  2182 follow natural argument order (for use with fold etc.);
  2183 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2184 
  2185 * Pure/General: output via the Isabelle channels of
  2186 writeln/warning/error etc. is now passed through Output.output, with a
  2187 hook for arbitrary transformations depending on the print_mode
  2188 (cf. Output.add_mode -- the first active mode that provides a output
  2189 function wins).  Already formatted output may be embedded into further
  2190 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2191 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2192 accommodate easy composition of diagnostic messages etc.  Programmers
  2193 rarely need to care about Output.output or Output.raw at all, with
  2194 some notable exceptions: Output.output is required when bypassing the
  2195 standard channels (writeln etc.), or in token translations to produce
  2196 properly formatted results; Output.raw is required when capturing
  2197 already output material that will eventually be presented to the user
  2198 a second time.  For the default print mode, both Output.output and
  2199 Output.raw have no effect.
  2200 
  2201 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2202 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2203 cumulative results are displayed at the end of a batch session.
  2204 
  2205 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2206 replaced by File.platform_path and File.shell_path (with appropriate
  2207 hooks).  This provides a clean interface for unusual systems where the
  2208 internal and external process view of file names are different.
  2209 
  2210 * Pure: more efficient orders for basic syntactic entities: added
  2211 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2212 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2213 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2214 orders now -- potential INCOMPATIBILITY for code that depends on a
  2215 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2216 Library.sort_strings on result).
  2217 
  2218 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2219 fold_types traverse types/terms from left to right, observing natural
  2220 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2221 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2222 
  2223 * Pure: name spaces have been refined, with significant changes of the
  2224 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2225 to extern(_table).  The plain name entry path is superceded by a
  2226 general 'naming' context, which also includes the 'policy' to produce
  2227 a fully qualified name and external accesses of a fully qualified
  2228 name; NameSpace.extend is superceded by context dependent
  2229 Sign.declare_name.  Several theory and proof context operations modify
  2230 the naming context.  Especially note Theory.restore_naming and
  2231 ProofContext.restore_naming to get back to a sane state; note that
  2232 Theory.add_path is no longer sufficient to recover from
  2233 Theory.absolute_path in particular.
  2234 
  2235 * Pure: new flags short_names (default false) and unique_names
  2236 (default true) for controlling output of qualified names.  If
  2237 short_names is set, names are printed unqualified.  If unique_names is
  2238 reset, the name prefix is reduced to the minimum required to achieve
  2239 the original result when interning again, even if there is an overlap
  2240 with earlier declarations.
  2241 
  2242 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2243 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2244 (useful for printing error messages).  INCOMPATIBILITY.
  2245 
  2246 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2247 Theory.theory are now identified, referring to the universal
  2248 Context.theory (see Pure/context.ML).  Actual signature and theory
  2249 content is managed as theory data.  The old code and interfaces were
  2250 spread over many files and structures; the new arrangement introduces
  2251 considerable INCOMPATIBILITY to gain more clarity:
  2252 
  2253   Context -- theory management operations (name, identity, inclusion,
  2254     parents, ancestors, merge, etc.), plus generic theory data;
  2255 
  2256   Sign -- logical signature and syntax operations (declaring consts,
  2257     types, etc.), plus certify/read for common entities;
  2258 
  2259   Theory -- logical theory operations (stating axioms, definitions,
  2260     oracles), plus a copy of logical signature operations (consts,
  2261     types, etc.); also a few basic management operations (Theory.copy,
  2262     Theory.merge, etc.)
  2263 
  2264 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2265 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2266 for convenience -- they merely return the theory.
  2267 
  2268 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2269 
  2270 * Pure: the Isar proof context type is already defined early in Pure
  2271 as Context.proof (note that ProofContext.context and Proof.context are
  2272 aliases, where the latter is the preferred name).  This enables other
  2273 Isabelle components to refer to that type even before Isar is present.
  2274 
  2275 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2276 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2277 any of these kinds.  For example, Sign.intern typeK is now
  2278 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2279 Theory.hide_types.  Also note that former
  2280 Theory.hide_classes/types/consts are now
  2281 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2282 internalize their arguments!  INCOMPATIBILITY.
  2283 
  2284 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2285 datatype thmref (with constructors Name and NameSelection) instead of
  2286 plain string -- INCOMPATIBILITY;
  2287 
  2288 * Pure: cases produced by proof methods specify options, where NONE
  2289 means to remove case bindings -- INCOMPATIBILITY in
  2290 (RAW_)METHOD_CASES.
  2291 
  2292 * Pure: the following operations retrieve axioms or theorems from a
  2293 theory node or theory hierarchy, respectively:
  2294 
  2295   Theory.axioms_of: theory -> (string * term) list
  2296   Theory.all_axioms_of: theory -> (string * term) list
  2297   PureThy.thms_of: theory -> (string * thm) list
  2298   PureThy.all_thms_of: theory -> (string * thm) list
  2299 
  2300 * Pure: print_tac now outputs the goal through the trace channel.
  2301 
  2302 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2303 Reference Toplevel.debug (default false) controls detailed printing
  2304 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2305 controls execution profiling -- set to 1 for time and 2 for space
  2306 (both increase the runtime).
  2307 
  2308 * Isar session: The initial use of ROOT.ML is now always timed,
  2309 i.e. the log will show the actual process times, in contrast to the
  2310 elapsed wall-clock time that the outer shell wrapper produces.
  2311 
  2312 * Simplifier: improved handling of bound variables (nameless
  2313 representation, avoid allocating new strings).  Simprocs that invoke
  2314 the Simplifier recursively should use Simplifier.inherit_bounds to
  2315 avoid local name clashes.  Failure to do so produces warnings
  2316 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2317 for further details.
  2318 
  2319 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2320 bindings for all theorems stored within a given theory; this may help
  2321 in porting non-Isar theories to Isar ones, while keeping ML proof
  2322 scripts for the time being.
  2323 
  2324 * ML operator HTML.with_charset specifies the charset begin used for
  2325 generated HTML files.  For example:
  2326 
  2327   HTML.with_charset "utf-8" use_thy "Hebrew";
  2328   HTML.with_charset "utf-8" use_thy "Chinese";
  2329 
  2330 
  2331 *** System ***
  2332 
  2333 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2334 isabelle, isatool etc.).
  2335 
  2336 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2337 isatool doc, isatool mkdir, display_drafts etc.).
  2338 
  2339 * isatool usedir: option -f allows specification of the ML file to be
  2340 used by Isabelle; default is ROOT.ML.
  2341 
  2342 * New isatool version outputs the version identifier of the Isabelle
  2343 distribution being used.
  2344 
  2345 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2346 (containing Boolean satisfiability problems) into Isabelle/HOL
  2347 theories.
  2348 
  2349 
  2350 
  2351 New in Isabelle2004 (April 2004)
  2352 --------------------------------
  2353 
  2354 *** General ***
  2355 
  2356 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2357   Replaces linorder.ML.
  2358 
  2359 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2360   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2361   (\<a>...\<z>), are now considered normal letters, and can therefore
  2362   be used anywhere where an ASCII letter (a...zA...Z) has until
  2363   now. COMPATIBILITY: This obviously changes the parsing of some
  2364   terms, especially where a symbol has been used as a binder, say
  2365   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2366   as an identifier.  Fix it by inserting a space around former
  2367   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2368   existing theory and ML files.
  2369 
  2370 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2371 
  2372 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2373   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2374   a normal (but invisible) letter. For multiple letter subscripts repeat
  2375   \<^isub> like this: x\<^isub>1\<^isub>2.
  2376 
  2377 * Pure: There are now sub-/superscripts that can span more than one
  2378   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2379   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2380   superscript. The new control characters are not identifier parts.
  2381 
  2382 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2383   content of "..." to the latex file instead of \isacntrl... . The "..."
  2384   may consist of any printable characters excluding the end bracket >.
  2385 
  2386 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2387   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2388   declare constants "final", which prevents their being given a definition
  2389   later.  It is useful for constants whose behaviour is fixed axiomatically
  2390   rather than definitionally, such as the meta-logic connectives.
  2391 
  2392 * Pure: 'instance' now handles general arities with general sorts
  2393   (i.e. intersections of classes),
  2394 
  2395 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2396   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2397   It can be changed to alter the colors/layout of generated pages.
  2398 
  2399 
  2400 *** Isar ***
  2401 
  2402 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2403   cut_tac, subgoal_tac and thin_tac:
  2404   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2405     locales are no longer forced to write Isar proof scripts.
  2406     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2407     emulations.
  2408   - INCOMPATIBILITY: names of variables to be instantiated may no
  2409     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2410     This is consistent with the instantiation attribute "where".
  2411 
  2412 * Attributes "where" and "of":
  2413   - Now take type variables of instantiated theorem into account when reading
  2414     the instantiation string.  This fixes a bug that caused instantiated
  2415     theorems to have too special types in some circumstances.
  2416   - "where" permits explicit instantiations of type variables.
  2417 
  2418 * Calculation commands "moreover" and "also" no longer interfere with
  2419   current facts ("this"), admitting arbitrary combinations with "then"
  2420   and derived forms.
  2421 
  2422 * Locales:
  2423   - Goal statements involving the context element "includes" no longer
  2424     generate theorems with internal delta predicates (those ending on
  2425     "_axioms") in the premise.
  2426     Resolve particular premise with <locale>.intro to obtain old form.
  2427   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2428     specification and "includes" elements in goal statement.
  2429   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2430     [intro?] and [elim?] (respectively) by default.
  2431   - Experimental command for instantiation of locales in proof contexts:
  2432         instantiate <label>[<attrs>]: <loc>
  2433     Instantiates locale <loc> and adds all its theorems to the current context
  2434     taking into account their attributes.  Label and attrs are optional
  2435     modifiers, like in theorem declarations.  If present, names of
  2436     instantiated theorems are qualified with <label>, and the attributes
  2437     <attrs> are applied after any attributes these theorems might have already.
  2438       If the locale has assumptions, a chained fact of the form
  2439     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2440     are derived.  The command does not support old-style locales declared
  2441     with "locale (open)".
  2442       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2443 
  2444 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2445   (Isar) contexts.
  2446 
  2447 
  2448 *** HOL ***
  2449 
  2450 * Proof import: new image HOL4 contains the imported library from
  2451   the HOL4 system with about 2500 theorems. It is imported by
  2452   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2453   can be used like any other Isabelle image.  See
  2454   HOL/Import/HOL/README for more information.
  2455 
  2456 * Simplifier:
  2457   - Much improved handling of linear and partial orders.
  2458     Reasoners for linear and partial orders are set up for type classes
  2459     "linorder" and "order" respectively, and are added to the default simpset
  2460     as solvers.  This means that the simplifier can build transitivity chains
  2461     to solve goals from the assumptions.
  2462   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2463     of blast or auto after simplification become unnecessary because the goal
  2464     is solved by simplification already.
  2465 
  2466 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2467     all proved in axiomatic type classes for semirings, rings and fields.
  2468 
  2469 * Numerics:
  2470   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2471     now formalized using the Ring_and_Field theory mentioned above.
  2472   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2473     than before, because now they are set up once in a generic manner.
  2474   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2475     Look for the general versions in Ring_and_Field (and Power if they concern
  2476     exponentiation).
  2477 
  2478 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2479 
  2480 * Records:
  2481   - Record types are now by default printed with their type abbreviation
  2482     instead of the list of all field types. This can be configured via
  2483     the reference "print_record_type_abbr".
  2484   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2485     (not enabled by default).
  2486   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2487     EX x. x = sel r to True (not enabled by default).
  2488   - Tactic "record_split_simp_tac" to split and simplify records added.
  2489 
  2490 * 'specification' command added, allowing for definition by
  2491   specification.  There is also an 'ax_specification' command that
  2492   introduces the new constants axiomatically.
  2493 
  2494 * arith(_tac) is now able to generate counterexamples for reals as well.
  2495 
  2496 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2497 
  2498 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2499   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2500 
  2501 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2502   matrix theory to linear programming.
  2503 
  2504 * Unions and Intersections:
  2505   The latex output syntax of UN and INT has been changed
  2506   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2507   i.e. the index formulae has become a subscript.
  2508   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2509 
  2510 * Unions and Intersections over Intervals:
  2511   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2512   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2513   like in normal math, and corresponding versions for < and for intersection.
  2514 
  2515 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2516   lexicographic dictonary ordering has been added as "lexord".
  2517 
  2518 * ML: the legacy theory structures Int and List have been removed. They had
  2519   conflicted with ML Basis Library structures having the same names.
  2520 
  2521 * 'refute' command added to search for (finite) countermodels.  Only works
  2522   for a fragment of HOL.  The installation of an external SAT solver is
  2523   highly recommended.  See "HOL/Refute.thy" for details.
  2524 
  2525 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2526   formulae under an assignment of free variables to random values.
  2527   In contrast to 'refute', it can deal with inductive datatypes,
  2528   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2529   for examples.
  2530 
  2531 
  2532 *** HOLCF ***
  2533 
  2534 * Streams now come with concatenation and are part of the HOLCF image
  2535 
  2536 
  2537 
  2538 New in Isabelle2003 (May 2003)
  2539 ------------------------------
  2540 
  2541 *** General ***
  2542 
  2543 * Provers/simplifier:
  2544 
  2545   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2546     Assumptions are now subject to complete mutual simplification,
  2547     not just from left to right. The simplifier now preserves
  2548     the order of assumptions.
  2549 
  2550     Potential INCOMPATIBILITY:
  2551 
  2552     -- simp sometimes diverges where the old version did
  2553        not, e.g. invoking simp on the goal
  2554 
  2555         [| P (f x); y = x; f x = f y |] ==> Q
  2556 
  2557        now gives rise to the infinite reduction sequence
  2558 
  2559         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2560 
  2561        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2562        kind of problem.
  2563 
  2564     -- Tactics combining classical reasoner and simplification (such as auto)
  2565        are also affected by this change, because many of them rely on
  2566        simp. They may sometimes diverge as well or yield a different numbers
  2567        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2568        in case of problems. Sometimes subsequent calls to the classical
  2569        reasoner will fail because a preceeding call to the simplifier too
  2570        eagerly simplified the goal, e.g. deleted redundant premises.
  2571 
  2572   - The simplifier trace now shows the names of the applied rewrite rules
  2573 
  2574   - You can limit the number of recursive invocations of the simplifier
  2575     during conditional rewriting (where the simplifie tries to solve the
  2576     conditions before applying the rewrite rule):
  2577     ML "simp_depth_limit := n"
  2578     where n is an integer. Thus you can force termination where previously
  2579     the simplifier would diverge.
  2580 
  2581   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2582 
  2583   - No longer aborts on failed congruence proof.  Instead, the
  2584     congruence is ignored.
  2585 
  2586 * Pure: New generic framework for extracting programs from constructive
  2587   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2588   as HOL/Extraction for some case studies.
  2589 
  2590 * Pure: The main goal of the proof state is no longer shown by default, only
  2591 the subgoals. This behaviour is controlled by a new flag.
  2592    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2593 (ML: Proof.show_main_goal).
  2594 
  2595 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2596 rules whose conclusion matches subgoal 1:
  2597       PG menu: Isabelle/Isar -> Show me -> matching rules
  2598 The rules are ordered by how closely they match the subgoal.
  2599 In particular, rules that solve a subgoal outright are displayed first
  2600 (or rather last, the way they are printed).
  2601 (ML: ProofGeneral.print_intros())
  2602 
  2603 * Pure: New flag trace_unify_fail causes unification to print
  2604 diagnostic information (PG: in trace buffer) when it fails. This is
  2605 useful for figuring out why single step proofs like rule, erule or
  2606 assumption failed.
  2607 
  2608 * Pure: Locale specifications now produce predicate definitions
  2609 according to the body of text (covering assumptions modulo local
  2610 definitions); predicate "loc_axioms" covers newly introduced text,
  2611 while "loc" is cumulative wrt. all included locale expressions; the
  2612 latter view is presented only on export into the global theory
  2613 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2614 on the old view without predicates;
  2615 
  2616 * Pure: predefined locales "var" and "struct" are useful for sharing
  2617 parameters (as in CASL, for example); just specify something like
  2618 ``var x + var y + struct M'' as import;
  2619 
  2620 * Pure: improved thms_containing: proper indexing of facts instead of
  2621 raw theorems; check validity of results wrt. current name space;
  2622 include local facts of proof configuration (also covers active
  2623 locales), cover fixed variables in index; may use "_" in term
  2624 specification; an optional limit for the number of printed facts may
  2625 be given (the default is 40);
  2626 
  2627 * Pure: disallow duplicate fact bindings within new-style theory files
  2628 (batch-mode only);
  2629 
  2630 * Provers: improved induct method: assumptions introduced by case
  2631 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2632 the goal statement); "foo" still refers to all facts collectively;
  2633 
  2634 * Provers: the function blast.overloaded has been removed: all constants
  2635 are regarded as potentially overloaded, which improves robustness in exchange
  2636 for slight decrease in efficiency;
  2637 
  2638 * Provers/linorder: New generic prover for transitivity reasoning over
  2639 linear orders.  Note: this prover is not efficient!
  2640 
  2641 * Isar: preview of problems to finish 'show' now produce an error
  2642 rather than just a warning (in interactive mode);
  2643 
  2644 
  2645 *** HOL ***
  2646 
  2647 * arith(_tac)
  2648 
  2649  - Produces a counter example if it cannot prove a goal.
  2650    Note that the counter example may be spurious if the goal is not a formula
  2651    of quantifier-free linear arithmetic.
  2652    In ProofGeneral the counter example appears in the trace buffer.
  2653 
  2654  - Knows about div k and mod k where k is a numeral of type nat or int.
  2655 
  2656  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2657    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2658    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2659 
  2660 * simp's arithmetic capabilities have been enhanced a bit: it now
  2661 takes ~= in premises into account (by performing a case split);
  2662 
  2663 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2664 are distributed over a sum of terms;
  2665 
  2666 * New tactic "trans_tac" and method "trans" instantiate
  2667 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2668 "<=", "<" and "=").
  2669 
  2670 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2671 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2672 
  2673 * 'typedef' command has new option "open" to suppress the set
  2674 definition;
  2675 
  2676 * functions Min and Max on finite sets have been introduced (theory
  2677 Finite_Set);
  2678 
  2679 * attribute [symmetric] now works for relations as well; it turns
  2680 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2681 
  2682 * induct over a !!-quantified statement (say !!x1..xn):
  2683   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2684 
  2685 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2686 %x. None. Warning: empty_def now refers to the previously hidden definition
  2687 of the empty set.
  2688 
  2689 * Algebra: formalization of classical algebra.  Intended as base for
  2690 any algebraic development in Isabelle.  Currently covers group theory
  2691 (up to Sylow's theorem) and ring theory (Universal Property of
  2692 Univariate Polynomials).  Contributions welcome;
  2693 
  2694 * GroupTheory: deleted, since its material has been moved to Algebra;
  2695 
  2696 * Complex: new directory of the complex numbers with numeric constants,
  2697 nonstandard complex numbers, and some complex analysis, standard and
  2698 nonstandard (Jacques Fleuriot);
  2699 
  2700 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2701 
  2702 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2703 Fleuriot);
  2704 
  2705 * Real/HahnBanach: updated and adapted to locales;
  2706 
  2707 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2708 Gray and Kramer);
  2709 
  2710 * UNITY: added the Meier-Sanders theory of progress sets;
  2711 
  2712 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2713 as abstract algorithms, instantiated to the JVM;
  2714 
  2715 * Bali: Java source language formalization. Type system, operational
  2716 semantics, axiomatic semantics. Supported language features:
  2717 classes, interfaces, objects,virtual methods, static methods,
  2718 static/instance fields, arrays, access modifiers, definite
  2719 assignment, exceptions.
  2720 
  2721 
  2722 *** ZF ***
  2723 
  2724 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2725 universe, etc.);
  2726 
  2727 * Main ZF: virtually all theories converted to new-style format;
  2728 
  2729 
  2730 *** ML ***
  2731 
  2732 * Pure: Tactic.prove provides sane interface for internal proofs;
  2733 omits the infamous "standard" operation, so this is more appropriate
  2734 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2735 
  2736 * Pure: improved error reporting of simprocs;
  2737 
  2738 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2739 up simprocs;
  2740 
  2741 
  2742 *** Document preparation ***
  2743 
  2744 * uses \par instead of \\ for line breaks in theory text. This may
  2745 shift some page breaks in large documents. To get the old behaviour
  2746 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2747 
  2748 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2749 other packages
  2750 
  2751 * \<euro> now needs package babel/greek instead of marvosym (which
  2752 broke \Rightarrow)
  2753 
  2754 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2755 textcomp package)
  2756 
  2757 
  2758 
  2759 New in Isabelle2002 (March 2002)
  2760 --------------------------------
  2761 
  2762 *** Document preparation ***
  2763 
  2764 * greatly simplified document preparation setup, including more
  2765 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2766 instructive isatool mkdir; users should basically be able to get
  2767 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2768 users may run a separate document processing stage manually like this:
  2769 "isatool usedir -D output HOL Test && isatool document Test/output";
  2770 
  2771 * theory dependency graph may now be incorporated into documents;
  2772 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2773 with \includegraphics of LaTeX;
  2774 
  2775 * proper spacing of consecutive markup elements, especially text
  2776 blocks after section headings;
  2777 
  2778 * support bold style (for single symbols only), input syntax is like
  2779 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2780 
  2781 * \<bullet> is now output as bold \cdot by default, which looks much
  2782 better in printed text;
  2783 
  2784 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2785 note that these symbols are currently unavailable in Proof General /
  2786 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2787 
  2788 * isatool latex no longer depends on changed TEXINPUTS, instead
  2789 isatool document copies the Isabelle style files to the target
  2790 location;
  2791 
  2792 
  2793 *** Isar ***
  2794 
  2795 * Pure/Provers: improved proof by cases and induction;
  2796   - 'case' command admits impromptu naming of parameters (such as
  2797     "case (Suc n)");
  2798   - 'induct' method divinates rule instantiation from the inductive
  2799     claim; no longer requires excessive ?P bindings for proper
  2800     instantiation of cases;
  2801   - 'induct' method properly enumerates all possibilities of set/type
  2802     rules; as a consequence facts may be also passed through *type*
  2803     rules without further ado;
  2804   - 'induct' method now derives symbolic cases from the *rulified*
  2805     rule (before it used to rulify cases stemming from the internal
  2806     atomized version); this means that the context of a non-atomic
  2807     statement becomes is included in the hypothesis, avoiding the
  2808     slightly cumbersome show "PROP ?case" form;
  2809   - 'induct' may now use elim-style induction rules without chaining
  2810     facts, using ``missing'' premises from the goal state; this allows
  2811     rules stemming from inductive sets to be applied in unstructured
  2812     scripts, while still benefitting from proper handling of non-atomic
  2813     statements; NB: major inductive premises need to be put first, all
  2814     the rest of the goal is passed through the induction;
  2815   - 'induct' proper support for mutual induction involving non-atomic
  2816     rule statements (uses the new concept of simultaneous goals, see
  2817     below);
  2818   - append all possible rule selections, but only use the first
  2819     success (no backtracking);
  2820   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2821   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2822   - added 'print_induct_rules' (covered by help item in recent Proof
  2823     General versions);
  2824   - moved induct/cases attributes to Pure, methods to Provers;
  2825   - generic method setup instantiated for FOL and HOL;
  2826 
  2827 * Pure: support multiple simultaneous goal statements, for example
  2828 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2829 meta-level mechanism, this acts as if several individual goals had
  2830 been stated separately; in particular common proof methods need to be
  2831 repeated in order to cover all claims; note that a single elimination
  2832 step is *not* sufficient to establish the two conjunctions, so this
  2833 fails:
  2834 
  2835   assume "A & B" then have A and B ..   (*".." fails*)
  2836 
  2837 better use "obtain" in situations as above; alternative refer to
  2838 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2839 
  2840 * Pure: proper integration with ``locales''; unlike the original
  2841 version by Florian Kammller, Isar locales package high-level proof
  2842 contexts rather than raw logical ones (e.g. we admit to include
  2843 attributes everywhere); operations on locales include merge and
  2844 rename; support for implicit arguments (``structures''); simultaneous
  2845 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2846 some examples;
  2847 
  2848 * Pure: the following commands have been ``localized'', supporting a
  2849 target locale specification "(in name)": 'lemma', 'theorem',
  2850 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2851 stored both within the locale and at the theory level (exported and
  2852 qualified by the locale name);
  2853 
  2854 * Pure: theory goals may now be specified in ``long'' form, with
  2855 ad-hoc contexts consisting of arbitrary locale elements. for example
  2856 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2857 definitions may be given, too); the result is a meta-level rule with
  2858 the context elements being discharged in the obvious way;
  2859 
  2860 * Pure: new proof command 'using' allows to augment currently used
  2861 facts after a goal statement ('using' is syntactically analogous to
  2862 'apply', but acts on the goal's facts only); this allows chained facts
  2863 to be separated into parts given before and after a claim, as in
  2864 ``from a and b have C using d and e <proof>'';
  2865 
  2866 * Pure: renamed "antecedent" case to "rule_context";
  2867 
  2868 * Pure: new 'judgment' command records explicit information about the
  2869 object-logic embedding (used by several tools internally); no longer
  2870 use hard-wired "Trueprop";
  2871 
  2872 * Pure: added 'corollary' command;
  2873 
  2874 * Pure: fixed 'token_translation' command;
  2875 
  2876 * Pure: removed obsolete 'exported' attribute;
  2877 
  2878 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2879 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2880 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2881 
  2882 * Pure: method 'atomize' presents local goal premises as object-level
  2883 statements (atomic meta-level propositions); setup controlled via
  2884 rewrite rules declarations of 'atomize' attribute; example
  2885 application: 'induct' method with proper rule statements in improper
  2886 proof *scripts*;
  2887 
  2888 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2889 now consider the syntactic context of assumptions, giving a better
  2890 chance to get type-inference of the arguments right (this is
  2891 especially important for locales);
  2892 
  2893 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2894 mode;
  2895 
  2896 * Pure/obtain: the formal conclusion "thesis", being marked as
  2897 ``internal'', may no longer be reference directly in the text;
  2898 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2899 situations;
  2900 
  2901 * Pure: generic 'sym' attribute which declares a rule both as pure
  2902 'elim?' and for the 'symmetric' operation;
  2903 
  2904 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2905 text; the fixed correlation with particular command syntax has been
  2906 discontinued;
  2907 
  2908 * Pure: new method 'rules' is particularly well-suited for proof
  2909 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2910 but often produces more compact proof terms with less detours;
  2911 
  2912 * Pure/Provers/classical: simplified integration with pure rule
  2913 attributes and methods; the classical "intro?/elim?/dest?"
  2914 declarations coincide with the pure ones; the "rule" method no longer
  2915 includes classically swapped intros; "intro" and "elim" methods no
  2916 longer pick rules from the context; also got rid of ML declarations
  2917 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2918 INCOMPATIBILITY;
  2919 
  2920 * Provers/classical: attribute 'swapped' produces classical inversions
  2921 of introduction rules;
  2922 
  2923 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2924 rules instead of full simplifier context; 'iff' attribute handles
  2925 conditional rules;
  2926 
  2927 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2928 
  2929 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2930 "(permissive)" option to recover old behavior;
  2931 
  2932 * HOL: 'inductive' no longer features separate (collective) attributes
  2933 for 'intros' (was found too confusing);
  2934 
  2935 * HOL: properly declared induction rules less_induct and
  2936 wf_induct_rule;
  2937 
  2938 
  2939 *** HOL ***
  2940 
  2941 * HOL: moved over to sane numeral syntax; the new policy is as
  2942 follows:
  2943 
  2944   - 0 and 1 are polymorphic constants, which are defined on any
  2945   numeric type (nat, int, real etc.);
  2946 
  2947   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2948   binary representation internally;
  2949 
  2950   - type nat has special constructor Suc, and generally prefers Suc 0
  2951   over 1::nat and Suc (Suc 0) over 2::nat;
  2952 
  2953 This change may cause significant problems of INCOMPATIBILITY; here
  2954 are some hints on converting existing sources:
  2955 
  2956   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2957   entities, so expressions involving "-" (unary or binary minus) need
  2958   to be spaced properly;
  2959 
  2960   - existing occurrences of "1" may need to be constraint "1::nat" or
  2961   even replaced by Suc 0; similar for old "2";
  2962 
  2963   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2964 
  2965   - remove all special provisions on numerals in proofs;
  2966 
  2967 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2968 representation (depends on bin_arith_simps in the default context);
  2969 
  2970 * HOL: symbolic syntax for x^2 (numeral 2);
  2971 
  2972 * HOL: the class of all HOL types is now called "type" rather than
  2973 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2974 in axclass/classes, instance/arities, and (usually rare) occurrences
  2975 in typings (of consts etc.); internally the class is called
  2976 "HOL.type", ML programs should refer to HOLogic.typeS;
  2977 
  2978 * HOL/record package improvements:
  2979   - new derived operations "fields" to build a partial record section,
  2980     "extend" to promote a fixed record to a record scheme, and
  2981     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2982     declared as simp by default;
  2983   - shared operations ("more", "fields", etc.) now need to be always
  2984     qualified) --- potential INCOMPATIBILITY;
  2985   - removed "make_scheme" operations (use "make" with "extend") --
  2986     INCOMPATIBILITY;
  2987   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2988   - provides cases/induct rules for use with corresponding Isar
  2989     methods (for concrete records, record schemes, concrete more
  2990     parts, and schematic more parts -- in that order);
  2991   - internal definitions directly based on a light-weight abstract
  2992     theory of product types over typedef rather than datatype;
  2993 
  2994 * HOL: generic code generator for generating executable ML code from
  2995 specifications; specific support for HOL constructs such as inductive
  2996 datatypes and sets, as well as recursive functions; can be invoked
  2997 via 'generate_code' theory section;
  2998 
  2999 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3000 
  3001 * HOL: consolidated and renamed several theories.  In particular:
  3002         Ord.thy has been absorbed into HOL.thy
  3003         String.thy has been absorbed into List.thy
  3004 
  3005 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3006 (beware of argument permutation!);
  3007 
  3008 * HOL: linorder_less_split superseded by linorder_cases;
  3009 
  3010 * HOL/List: "nodups" renamed to "distinct";
  3011 
  3012 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3013 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3014   - Ex_def has changed, now need to use some_eq_ex
  3015 
  3016 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3017 in this (rare) case use:
  3018 
  3019   delSWrapper "split_all_tac"
  3020   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3021 
  3022 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3023 MAY FAIL;
  3024 
  3025 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3026 Isabelle's type classes, ^ on functions and relations has too general
  3027 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3028 necessary to attach explicit type constraints;
  3029 
  3030 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3031 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3032 renamed accordingly (eg "compI" -> "rel_compI").
  3033 
  3034 * HOL: syntax translations now work properly with numerals and records
  3035 expressions;
  3036 
  3037 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3038 of "lam" -- INCOMPATIBILITY;
  3039 
  3040 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3041 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3042 renamed "Product_Type.unit";
  3043 
  3044 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3045 
  3046 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3047 the "cases" method);
  3048 
  3049 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3050 Florian Kammller);
  3051 
  3052 * HOL/IMP: updated and converted to new-style theory format; several
  3053 parts turned into readable document, with proper Isar proof texts and
  3054 some explanations (by Gerwin Klein);
  3055 
  3056 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3057 
  3058 * HOL-Hyperreal is now a logic image;
  3059 
  3060 
  3061 *** HOLCF ***
  3062 
  3063 * Isar: consts/constdefs supports mixfix syntax for continuous
  3064 operations;
  3065 
  3066 * Isar: domain package adapted to new-style theory format, e.g. see
  3067 HOLCF/ex/Dnat.thy;
  3068 
  3069 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3070 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3071 lift.induct_tac, always use UU instead of Undef;
  3072 
  3073 * HOLCF/IMP: updated and converted to new-style theory;
  3074 
  3075 
  3076 *** ZF ***
  3077 
  3078 * Isar: proper integration of logic-specific tools and packages,
  3079 including theory commands '(co)inductive', '(co)datatype',
  3080 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3081 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3082 
  3083 * theory Main no longer includes AC; for the Axiom of Choice, base
  3084 your theory on Main_ZFC;
  3085 
  3086 * the integer library now covers quotients and remainders, with many
  3087 laws relating division to addition, multiplication, etc.;
  3088 
  3089 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3090 typeless version of the formalism;
  3091 
  3092 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3093 format;
  3094 
  3095 * ZF/Induct: new directory for examples of inductive definitions,
  3096 including theory Multiset for multiset orderings; converted to
  3097 new-style theory format;
  3098 
  3099 * ZF: many new theorems about lists, ordinals, etc.;
  3100 
  3101 
  3102 *** General ***
  3103 
  3104 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3105 variable proof controls level of detail: 0 = no proofs (only oracle
  3106 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3107 also ref manual for further ML interfaces;
  3108 
  3109 * Pure/axclass: removed obsolete ML interface
  3110 goal_subclass/goal_arity;
  3111 
  3112 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3113 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3114 separate tokens, so expressions involving minus need to be spaced
  3115 properly;
  3116 
  3117 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3118 rather than "infixl" or "infixr";
  3119 
  3120 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3121 sort constraint specifications in type inference; e.g. "x::_::foo"
  3122 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3123 type variable);
  3124 
  3125 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3126 control output of nested => (types); the default behavior is
  3127 "type_brackets";
  3128 
  3129 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3130 tokens into AST constants;
  3131 
  3132 * Pure/syntax: prefer later declarations of translations and print
  3133 translation functions; potential INCOMPATIBILITY: need to reverse
  3134 multiple declarations for same syntax element constant;
  3135 
  3136 * Pure/show_hyps reset by default (in accordance to existing Isar
  3137 practice);
  3138 
  3139 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3140 addSafter;
  3141 
  3142 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3143 as well;
  3144 
  3145 * system: tested support for MacOS X; should be able to get Isabelle +
  3146 Proof General to work in a plain Terminal after installing Poly/ML
  3147 (e.g. from the Isabelle distribution area) and GNU bash alone
  3148 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3149 support requires further installations, e.g. from
  3150 http://fink.sourceforge.net/);
  3151 
  3152 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3153 
  3154 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3155 of 40 MB), cf. ML_OPTIONS;
  3156 
  3157 * system: Proof General keywords specification is now part of the
  3158 Isabelle distribution (see etc/isar-keywords.el);
  3159 
  3160 * system: support for persistent Proof General sessions (refrain from
  3161 outdating all loaded theories on startup); user may create writable
  3162 logic images like this: ``isabelle -q HOL Test'';
  3163 
  3164 * system: smart selection of Isabelle process versus Isabelle
  3165 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3166 run both "isabelle" and "Isabelle" even if file names are badly
  3167 damaged (executable inspects the case of the first letter of its own
  3168 name); added separate "isabelle-process" and "isabelle-interface";
  3169 
  3170 * system: refrain from any attempt at filtering input streams; no
  3171 longer support ``8bit'' encoding of old isabelle font, instead proper
  3172 iso-latin characters may now be used; the related isatools
  3173 "symbolinput" and "nonascii" have disappeared as well;
  3174 
  3175 * system: removed old "xterm" interface (the print modes "xterm" and
  3176 "xterm_color" are still available for direct use in a suitable
  3177 terminal);
  3178 
  3179 
  3180 
  3181 New in Isabelle99-2 (February 2001)
  3182 -----------------------------------
  3183 
  3184 *** Overview of INCOMPATIBILITIES ***
  3185 
  3186 * HOL: please note that theories in the Library and elsewhere often use the
  3187 new-style (Isar) format; to refer to their theorems in an ML script you must
  3188 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3189 
  3190 * HOL: inductive package no longer splits induction rule aggressively,
  3191 but only as far as specified by the introductions given; the old
  3192 format may be recovered via ML function complete_split_rule or attribute
  3193 'split_rule (complete)';
  3194 
  3195 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3196 gfp_Tarski to gfp_unfold;
  3197 
  3198 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3199 
  3200 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3201 relation); infix "^^" has been renamed "``"; infix "``" has been
  3202 renamed "`"; "univalent" has been renamed "single_valued";
  3203 
  3204 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3205 operation;
  3206 
  3207 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3208 
  3209 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3210 
  3211 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3212 consequence, it is no longer monotonic wrt. the local goal context
  3213 (which is now passed through the inductive cases);
  3214 
  3215 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3216 \<gg> to \<ggreater>;
  3217 
  3218 
  3219 *** Document preparation ***
  3220 
  3221 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3222 available: are "it" for near math-mode best-style output, "sl" for
  3223 slanted text style, and "tt" for plain type-writer; if no
  3224 \isabellestyle command is given, output is according to slanted
  3225 type-writer);
  3226 
  3227 * support sub/super scripts (for single symbols only), input syntax is
  3228 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3229 
  3230 * some more standard symbols; see Appendix A of the system manual for
  3231 the complete list of symbols defined in isabellesym.sty;
  3232 
  3233 * improved isabelle style files; more abstract symbol implementation
  3234 (should now use \isamath{...} and \isatext{...} in custom symbol
  3235 definitions);
  3236 
  3237 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3238 state; Note that presentation of goal states does not conform to
  3239 actual human-readable proof documents.  Please do not include goal
  3240 states into document output unless you really know what you are doing!
  3241 
  3242 * proper indentation of antiquoted output with proportional LaTeX
  3243 fonts;
  3244 
  3245 * no_document ML operator temporarily disables LaTeX document
  3246 generation;
  3247 
  3248 * isatool unsymbolize tunes sources for plain ASCII communication;
  3249 
  3250 
  3251 *** Isar ***
  3252 
  3253 * Pure: Isar now suffers initial goal statements to contain unbound
  3254 schematic variables (this does not conform to actual readable proof
  3255 documents, due to unpredictable outcome and non-compositional proof
  3256 checking); users who know what they are doing may use schematic goals
  3257 for Prolog-style synthesis of proven results;
  3258 
  3259 * Pure: assumption method (an implicit finishing) now handles actual
  3260 rules as well;
  3261 
  3262 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3263 initial goal, declare "that" only as Pure intro (only for single
  3264 steps); the "that" rule assumption may now be involved in implicit
  3265 finishing, thus ".." becomes a feasible for trivial obtains;
  3266 
  3267 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3268 instance proofs may be performed by "..";
  3269 
  3270 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3271 statements as well;
  3272 
  3273 * Pure: more robust selection of calculational rules;
  3274 
  3275 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3276 rule (as well as the assumption rule);
  3277 
  3278 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3279 lemmas, using the graph browser tool;
  3280 
  3281 * Pure: predict failure of "show" in interactive mode;
  3282 
  3283 * Pure: 'thms_containing' now takes actual terms as arguments;
  3284 
  3285 * HOL: improved method 'induct' --- now handles non-atomic goals
  3286 (potential INCOMPATIBILITY); tuned error handling;
  3287 
  3288 * HOL: cases and induct rules now provide explicit hints about the
  3289 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3290 any remaining facts are inserted into the goal verbatim;
  3291 
  3292 * HOL: local contexts (aka cases) may now contain term bindings as
  3293 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3294 the result to be shown in each case;
  3295 
  3296 * HOL: added 'recdef_tc' command;
  3297 
  3298 * isatool convert assists in eliminating legacy ML scripts;
  3299 
  3300 
  3301 *** HOL ***
  3302 
  3303 * HOL/Library: a collection of generic theories to be used together
  3304 with main HOL; the theory loader path already includes this directory
  3305 by default; the following existing theories have been moved here:
  3306 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3307 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3308 
  3309 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3310 modelling and verification task performed in Isabelle/HOL +
  3311 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3312 
  3313 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3314 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3315 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3316 'domain', this makes the theory consistent with mathematical
  3317 literature;
  3318 
  3319 * HOL basics: added overloaded operations "inverse" and "divide"
  3320 (infix "/"), syntax for generic "abs" operation, generic summation
  3321 operator \<Sum>;
  3322 
  3323 * HOL/typedef: simplified package, provide more useful rules (see also
  3324 HOL/subset.thy);
  3325 
  3326 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3327 now expressed as a proper nested rule (old-style tactic scripts may
  3328 require atomize_strip_tac to cope with non-atomic premises);
  3329 
  3330 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3331 to "split_conv" (old name still available for compatibility);
  3332 
  3333 * HOL: improved concrete syntax for strings (e.g. allows translation
  3334 rules with string literals);
  3335 
  3336 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3337  and Fleuriot's mechanization of analysis, including the transcendental
  3338  functions for the reals;
  3339 
  3340 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3341 
  3342 
  3343 *** CTT ***
  3344 
  3345 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3346 "lam" is displayed as TWO lambda-symbols
  3347 
  3348 * CTT: theory Main now available, containing everything (that is, Bool
  3349 and Arith);
  3350 
  3351 
  3352 *** General ***
  3353 
  3354 * Pure: the Simplifier has been implemented properly as a derived rule
  3355 outside of the actual kernel (at last!); the overall performance
  3356 penalty in practical applications is about 50%, while reliability of
  3357 the Isabelle inference kernel has been greatly improved;
  3358 
  3359 * print modes "brackets" and "no_brackets" control output of nested =>
  3360 (types) and ==> (props); the default behaviour is "brackets";
  3361 
  3362 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3363 as assumptions as well;
  3364 
  3365 * system: support Poly/ML 4.0;
  3366 
  3367 * system: isatool install handles KDE version 1 or 2;
  3368 
  3369 
  3370 
  3371 New in Isabelle99-1 (October 2000)
  3372 ----------------------------------
  3373 
  3374 *** Overview of INCOMPATIBILITIES ***
  3375 
  3376 * HOL: simplification of natural numbers is much changed; to partly
  3377 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3378 issue the following ML commands:
  3379 
  3380   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3381   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3382 
  3383 * HOL: simplification no longer dives into case-expressions; this is
  3384 controlled by "t.weak_case_cong" for each datatype t;
  3385 
  3386 * HOL: nat_less_induct renamed to less_induct;
  3387 
  3388 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3389 fixsome to patch .thy and .ML sources automatically;
  3390 
  3391   select_equality  -> some_equality
  3392   select_eq_Ex     -> some_eq_ex
  3393   selectI2EX       -> someI2_ex
  3394   selectI2         -> someI2
  3395   selectI          -> someI
  3396   select1_equality -> some1_equality
  3397   Eps_sym_eq       -> some_sym_eq_trivial
  3398   Eps_eq           -> some_eq_trivial
  3399 
  3400 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3401 
  3402 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3403 instead);
  3404 
  3405 * HOL: the recursion equations generated by 'recdef' are now called
  3406 f.simps instead of f.rules;
  3407 
  3408 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3409 
  3410 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3411 sometimes be needed;
  3412 
  3413 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3414 
  3415 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3416 
  3417 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3418 product is now "<*>" instead of "Times"; the lexicographic product is
  3419 now "<*lex*>" instead of "**";
  3420 
  3421 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3422 of main HOL, but was unused); better use HOL's datatype package;
  3423 
  3424 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3425 the old syntax may be recovered as follows:
  3426 
  3427   syntax (symbols)
  3428     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3429       (infixl "\\<oplus>" 100)
  3430 
  3431 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3432 
  3433 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3434 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3435 internally;
  3436 
  3437 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3438 changed from A/r to A//r;
  3439 
  3440 * ZF: new treatment of arithmetic (nat & int) may break some old
  3441 proofs;
  3442 
  3443 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3444 rulify -> rule_format, elimify -> elim_format, ...);
  3445 
  3446 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3447 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3448 should have to change intro!! to intro? only); replaced "delrule" by
  3449 "rule del";
  3450 
  3451 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3452 
  3453 * Provers: strengthened force_tac by using new first_best_tac;
  3454 
  3455 * LaTeX document preparation: several changes of isabelle.sty (see
  3456 lib/texinputs);
  3457 
  3458 
  3459 *** Document preparation ***
  3460 
  3461 * formal comments (text blocks etc.) in new-style theories may now
  3462 contain antiquotations of thm/prop/term/typ/text to be presented
  3463 according to latex print mode; concrete syntax is like this:
  3464 @{term[show_types] "f(x) = a + x"};
  3465 
  3466 * isatool mkdir provides easy setup of Isabelle session directories,
  3467 including proper document sources;
  3468 
  3469 * generated LaTeX sources are now deleted after successful run
  3470 (isatool document -c); may retain a copy somewhere else via -D option
  3471 of isatool usedir;
  3472 
  3473 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3474 style files, achieving self-contained LaTeX sources and simplifying
  3475 LaTeX debugging;
  3476 
  3477 * old-style theories now produce (crude) LaTeX output as well;
  3478 
  3479 * browser info session directories are now self-contained (may be put
  3480 on WWW server seperately); improved graphs of nested sessions; removed
  3481 graph for 'all sessions';
  3482 
  3483 * several improvements in isabelle style files; \isabellestyle{it}
  3484 produces fake math mode output; \isamarkupheader is now \section by
  3485 default; see lib/texinputs/isabelle.sty etc.;
  3486 
  3487 
  3488 *** Isar ***
  3489 
  3490 * Isar/Pure: local results and corresponding term bindings are now
  3491 subject to Hindley-Milner polymorphism (similar to ML); this
  3492 accommodates incremental type-inference very nicely;
  3493 
  3494 * Isar/Pure: new derived language element 'obtain' supports
  3495 generalized existence reasoning;
  3496 
  3497 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3498 support accumulation of results, without applying any rules yet;
  3499 useful to collect intermediate results without explicit name
  3500 references, and for use with transitivity rules with more than 2
  3501 premises;
  3502 
  3503 * Isar/Pure: scalable support for case-analysis type proofs: new
  3504 'case' language element refers to local contexts symbolically, as
  3505 produced by certain proof methods; internally, case names are attached
  3506 to theorems as "tags";
  3507 
  3508 * Isar/Pure: theory command 'hide' removes declarations from
  3509 class/type/const name spaces;
  3510 
  3511 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3512 indicate potential overloading;
  3513 
  3514 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3515 
  3516 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3517 "{a,b,c}" instead of {a,b,c};
  3518 
  3519 * Isar/Pure now provides its own version of intro/elim/dest
  3520 attributes; useful for building new logics, but beware of confusion
  3521 with the version in Provers/classical;
  3522 
  3523 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3524 case name 'antecedent';
  3525 
  3526 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3527 to the current context is now done automatically);
  3528 
  3529 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3530 for definining proof methods in ML;
  3531 
  3532 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3533 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3534 most cases, one should have to change intro!! to intro? only);
  3535 replaced "delrule" by "rule del";
  3536 
  3537 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3538 'symmetric' attribute (the latter supercedes [RS sym]);
  3539 
  3540 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3541 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3542 well (including splits);
  3543 
  3544 * Isar/Provers: Simplifier and Classical methods now support all kind
  3545 of modifiers used in the past, including 'cong', 'iff', etc.
  3546 
  3547 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3548 of Simplifier and Classical reasoner);
  3549 
  3550 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3551 now support named cases; major packages (inductive, datatype, primrec,
  3552 recdef) support case names and properly name parameters;
  3553 
  3554 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3555 monotonicity conditions are extracted to be proven at end of
  3556 calculations;
  3557 
  3558 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3559 method anyway;
  3560 
  3561 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3562 split_if split_if_asm; datatype package provides theorems foo.splits =
  3563 foo.split foo.split_asm for each datatype;
  3564 
  3565 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3566 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3567 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3568 use "(cases (simplified))" method in proper proof texts);
  3569 
  3570 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3571 
  3572 * Isar: names of theorems etc. may be natural numbers as well;
  3573 
  3574 * Isar: 'pr' command: optional arguments for goals_limit and
  3575 ProofContext.prems_limit; no longer prints theory contexts, but only
  3576 proof states;
  3577 
  3578 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3579 additional print modes to be specified; e.g. "pr(latex)" will print
  3580 proof state according to the Isabelle LaTeX style;
  3581 
  3582 * Isar: improved support for emulating tactic scripts, including proof
  3583 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3584 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3585 (for HOL datatypes);
  3586 
  3587 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3588 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3589 'proof method scripts' have to be in depth-first order;
  3590 
  3591 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3592 
  3593 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3594 should instead use individual commands for printing items
  3595 (print_commands, print_methods etc.);
  3596 
  3597 * Isar: added 'nothing' --- the empty list of theorems;
  3598 
  3599 
  3600 *** HOL ***
  3601 
  3602 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3603 corresponding virtual machine and a specification of its bytecode
  3604 verifier and a lightweight bytecode verifier, including proofs of
  3605 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3606 Cornelia Pusch (see also the homepage of project Bali at
  3607 http://isabelle.in.tum.de/Bali/);
  3608 
  3609 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3610 Clemens Ballarin;
  3611 
  3612 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3613 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3614 Rasmussen;
  3615 
  3616 * HOL/Lattice: fundamental concepts of lattice theory and order
  3617 structures, including duals, properties of bounds versus algebraic
  3618 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3619 Theorem for complete lattices etc.; may also serve as a demonstration
  3620 for abstract algebraic reasoning using axiomatic type classes, and
  3621 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3622 
  3623 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3624 von Oheimb;
  3625 
  3626 * HOL/IMPP: extension of IMP with local variables and mutually
  3627 recursive procedures, by David von Oheimb;
  3628 
  3629 * HOL/Lambda: converted into new-style theory and document;
  3630 
  3631 * HOL/ex/Multiquote: example of multiple nested quotations and
  3632 anti-quotations -- basically a generalized version of de-Bruijn
  3633 representation; very useful in avoiding lifting of operations;
  3634 
  3635 * HOL/record: added general record equality rule to simpset; fixed
  3636 select-update simplification procedure to handle extended records as
  3637 well; admit "r" as field name;
  3638 
  3639 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3640 other numeric types and also as the identity of groups, rings, etc.;
  3641 
  3642 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3643 Types nat and int belong to this axclass;
  3644 
  3645 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3646    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3647    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3648   two terms #m*u and #n*u are replaced by #(m+n)*u
  3649     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3650   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3651     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3652 
  3653 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3654 powerful prover for predicate logic but knows nothing of clasets; see
  3655 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3656 
  3657 * HOL: new version of "case_tac" subsumes both boolean case split and
  3658 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3659 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3660 
  3661 * HOL: simplification no longer dives into case-expressions: only the
  3662 selector expression is simplified, but not the remaining arms; to
  3663 enable full simplification of case-expressions for datatype t, you may
  3664 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3665 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3666 
  3667 * HOL/recdef: the recursion equations generated by 'recdef' for
  3668 function 'f' are now called f.simps instead of f.rules; if all
  3669 termination conditions are proved automatically, these simplification
  3670 rules are added to the simpset, as in primrec; rules may be named
  3671 individually as well, resulting in a separate list of theorems for
  3672 each equation;
  3673 
  3674 * HOL/While is a new theory that provides a while-combinator. It
  3675 permits the definition of tail-recursive functions without the
  3676 provision of a termination measure. The latter is necessary once the
  3677 invariant proof rule for while is applied.
  3678 
  3679 * HOL: new (overloaded) notation for the set of elements below/above
  3680 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3681 
  3682 * HOL: theorems impI, allI, ballI bound as "strip";
  3683 
  3684 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3685 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3686 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3687 
  3688 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3689 
  3690 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3691 main HOL, but was unused);
  3692 
  3693 * HOL: fewer consts declared as global (e.g. have to refer to
  3694 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3695 
  3696 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3697 in case of overlap with user translations (e.g. judgements over
  3698 tuples); (note that the underlying logical represenation is still
  3699 bogus);
  3700 
  3701 
  3702 *** ZF ***
  3703 
  3704 * ZF: simplification automatically cancels common terms in arithmetic
  3705 expressions over nat and int;
  3706 
  3707 * ZF: new treatment of nat to minimize type-checking: all operators
  3708 coerce their operands to a natural number using the function natify,
  3709 making the algebraic laws unconditional;
  3710 
  3711 * ZF: as above, for int: operators coerce their operands to an integer
  3712 using the function intify;
  3713 
  3714 * ZF: the integer library now contains many of the usual laws for the
  3715 orderings, including $<=, and monotonicity laws for $+ and $*;
  3716 
  3717 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3718 simplification;
  3719 
  3720 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3721 to the simplifier and classical reasoner simultaneously;
  3722 
  3723 
  3724 *** General ***
  3725 
  3726 * Provers: blast_tac now handles actual object-logic rules as
  3727 assumptions; note that auto_tac uses blast_tac internally as well;
  3728 
  3729 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3730 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3731 
  3732 * Provers: delrules now handles destruct rules as well (no longer need
  3733 explicit make_elim);
  3734 
  3735 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3736   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3737 use instead the strong form,
  3738   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3739 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3740 from destruct-rules;
  3741 
  3742 * Provers: Simplifier.easy_setup provides a fast path to basic
  3743 Simplifier setup for new object-logics;
  3744 
  3745 * Pure: AST translation rules no longer require constant head on LHS;
  3746 
  3747 * Pure: improved name spaces: ambiguous output is qualified; support
  3748 for hiding of names;
  3749 
  3750 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3751 XSYMBOL_HOME; no longer need to do manual configuration in most
  3752 situations;
  3753 
  3754 * system: compression of ML heaps images may now be controlled via -c
  3755 option of isabelle and isatool usedir (currently only observed by
  3756 Poly/ML);
  3757 
  3758 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3759 useful for remote X11);
  3760 
  3761 * system: provide TAGS file for Isabelle sources;
  3762 
  3763 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3764 order;
  3765 
  3766 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3767 timing flag supersedes proof_timing and Toplevel.trace;
  3768 
  3769 * ML: new combinators |>> and |>>> for incremental transformations
  3770 with secondary results (e.g. certain theory extensions):
  3771 
  3772 * ML: PureThy.add_defs gets additional argument to indicate potential
  3773 overloading (usually false);
  3774 
  3775 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3776 results;
  3777 
  3778 
  3779 
  3780 New in Isabelle99 (October 1999)
  3781 --------------------------------
  3782 
  3783 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3784 
  3785 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3786 are no longer simplified.  (This allows the simplifier to unfold recursive
  3787 functional programs.)  To restore the old behaviour, declare
  3788 
  3789     Delcongs [if_weak_cong];
  3790 
  3791 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3792 complement;
  3793 
  3794 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3795 
  3796 * HOL/datatype: mutual_induct_tac no longer exists --
  3797   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3798 
  3799 * HOL/typedef: fixed type inference for representing set; type
  3800 arguments now have to occur explicitly on the rhs as type constraints;
  3801 
  3802 * ZF: The con_defs part of an inductive definition may no longer refer
  3803 to constants declared in the same theory;
  3804 
  3805 * HOL, ZF: the function mk_cases, generated by the inductive
  3806 definition package, has lost an argument.  To simplify its result, it
  3807 uses the default simpset instead of a supplied list of theorems.
  3808 
  3809 * HOL/List: the constructors of type list are now Nil and Cons;
  3810 
  3811 * Simplifier: the type of the infix ML functions
  3812         setSSolver addSSolver setSolver addSolver
  3813 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3814 for packaging solvers. A solver is created via
  3815         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3816 where the string argument is only a comment.
  3817 
  3818 
  3819 *** Proof tools ***
  3820 
  3821 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3822 decision procedure for linear arithmetic. Currently it is used for
  3823 types `nat', `int', and `real' in HOL (see below); it can, should and
  3824 will be instantiated for other types and logics as well.
  3825 
  3826 * The simplifier now accepts rewrite rules with flexible heads, eg
  3827      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3828   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3829   matching.
  3830 
  3831 
  3832 *** General ***
  3833 
  3834 * New Isabelle/Isar subsystem provides an alternative to traditional
  3835 tactical theorem proving; together with the ProofGeneral/isar user
  3836 interface it offers an interactive environment for developing human
  3837 readable proof documents (Isar == Intelligible semi-automated
  3838 reasoning); for further information see isatool doc isar-ref,
  3839 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3840 
  3841 * improved and simplified presentation of theories: better HTML markup
  3842 (including colors), graph views in several sizes; isatool usedir now
  3843 provides a proper interface for user theories (via -P option); actual
  3844 document preparation based on (PDF)LaTeX is available as well (for
  3845 new-style theories only); see isatool doc system for more information;
  3846 
  3847 * native support for Proof General, both for classic Isabelle and
  3848 Isabelle/Isar;
  3849 
  3850 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3851 using the graph browser tool;
  3852 
  3853 * Isabelle manuals now also available as PDF;
  3854 
  3855 * theory loader rewritten from scratch (may not be fully
  3856 bug-compatible); old loadpath variable has been replaced by show_path,
  3857 add_path, del_path, reset_path functions; new operations such as
  3858 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3859 isatool doc ref);
  3860 
  3861 * improved isatool install: option -k creates KDE application icon,
  3862 option -p DIR installs standalone binaries;
  3863 
  3864 * added ML_PLATFORM setting (useful for cross-platform installations);
  3865 more robust handling of platform specific ML images for SML/NJ;
  3866 
  3867 * the settings environment is now statically scoped, i.e. it is never
  3868 created again in sub-processes invoked from isabelle, isatool, or
  3869 Isabelle;
  3870 
  3871 * path element specification '~~' refers to '$ISABELLE_HOME';
  3872 
  3873 * in locales, the "assumes" and "defines" parts may be omitted if
  3874 empty;
  3875 
  3876 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3877 long arrows);
  3878 
  3879 * new print_mode "HTML";
  3880 
  3881 * new flag show_tags controls display of tags of theorems (which are
  3882 basically just comments that may be attached by some tools);
  3883 
  3884 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3885 mode and goal output format:
  3886 
  3887 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3888 244c244
  3889 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3890 ---
  3891 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3892 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3893 181c181
  3894 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3895 ---
  3896 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3897 
  3898 * function bind_thms stores lists of theorems (cf. bind_thm);
  3899 
  3900 * new shorthand tactics ftac, eatac, datac, fatac;
  3901 
  3902 * qed (and friends) now accept "" as result name; in that case the
  3903 theorem is not stored, but proper checks and presentation of the
  3904 result still apply;
  3905 
  3906 * theorem database now also indexes constants "Trueprop", "all",
  3907 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3908 
  3909 
  3910 *** HOL ***
  3911 
  3912 ** HOL arithmetic **
  3913 
  3914 * There are now decision procedures for linear arithmetic over nat and
  3915 int:
  3916 
  3917 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3918 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3919 are treated as atomic; subformulae not involving type `nat' or `int'
  3920 are ignored; quantified subformulae are ignored unless they are
  3921 positive universal or negative existential. The tactic has to be
  3922 invoked by hand and can be a little bit slow. In particular, the
  3923 running time is exponential in the number of occurrences of `min' and
  3924 `max', and `-' on `nat'.
  3925 
  3926 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3927 (negated) (in)equalities among the premises and the conclusion into
  3928 account (i.e. no compound formulae) and does not know about `min' and
  3929 `max', and `-' on `nat'. It is fast and is used automatically by the
  3930 simplifier.
  3931 
  3932 NB: At the moment, these decision procedures do not cope with mixed
  3933 nat/int formulae where the two parts interact, such as `m < n ==>
  3934 int(m) < int(n)'.
  3935 
  3936 * HOL/Numeral provides a generic theory of numerals (encoded
  3937 efficiently as bit strings); setup for types nat/int/real is in place;
  3938 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3939 int, existing theories and proof scripts may require a few additional
  3940 type constraints;
  3941 
  3942 * integer division and remainder can now be performed on constant
  3943 arguments;
  3944 
  3945 * many properties of integer multiplication, division and remainder
  3946 are now available;
  3947 
  3948 * An interface to the Stanford Validity Checker (SVC) is available through the
  3949 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3950 are proved automatically.  SVC must be installed separately, and its results
  3951 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3952 invocation of the underlying oracle).  For SVC see
  3953   http://verify.stanford.edu/SVC
  3954 
  3955 * IsaMakefile: the HOL-Real target now builds an actual image;
  3956 
  3957 
  3958 ** HOL misc **
  3959 
  3960 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3961 (in Isabelle/Isar) -- by Gertrud Bauer;
  3962 
  3963 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3964 analysis for assembly languages with subtypes;
  3965 
  3966 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3967 -- avoids syntactic ambiguities and treats state, transition, and
  3968 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3969 changed syntax and (many) tactics;
  3970 
  3971 * HOL/inductive: Now also handles more general introduction rules such
  3972   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3973   theorems are now maintained within the theory (maintained via the
  3974   "mono" attribute);
  3975 
  3976 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3977   (using function types) such as
  3978 
  3979   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3980 
  3981 * HOL/record: record_simproc (part of the default simpset) takes care
  3982 of selectors applied to updated records; record_split_tac is no longer
  3983 part of the default claset; update_defs may now be removed from the
  3984 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3985 
  3986   claset_ref () := claset() addSWrapper record_split_wrapper;
  3987   Delsimprocs [record_simproc]
  3988 
  3989 * HOL/typedef: fixed type inference for representing set; type
  3990 arguments now have to occur explicitly on the rhs as type constraints;
  3991 
  3992 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3993 names rather than an ML expression;
  3994 
  3995 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3996 supplied later.  Program schemes can be defined, such as
  3997     "While B C s = (if B s then While B C (C s) else s)"
  3998 where the well-founded relation can be chosen after B and C have been given.
  3999 
  4000 * HOL/List: the constructors of type list are now Nil and Cons;
  4001 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4002 course, ML tools referring to List.list.op # etc. have to be adapted;
  4003 
  4004 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4005 disabled by default; run isabelle with option -m HOL to get back to
  4006 the original Gordon/HOL-style output;
  4007 
  4008 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4009 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4010 
  4011 * HOL basic syntax simplified (more orthogonal): all variants of
  4012 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4013 Eps operator is provided as well: "SOME x. P[x]";
  4014 
  4015 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4016 
  4017 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4018 thus available for user theories;
  4019 
  4020 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4021 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4022 time;
  4023 
  4024 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4025 several times and then mp;
  4026 
  4027 
  4028 *** LK ***
  4029 
  4030 * the notation <<...>> is now available as a notation for sequences of
  4031 formulas;
  4032 
  4033 * the simplifier is now installed
  4034 
  4035 * the axiom system has been generalized (thanks to Soren Heilmann)
  4036 
  4037 * the classical reasoner now has a default rule database
  4038 
  4039 
  4040 *** ZF ***
  4041 
  4042 * new primrec section allows primitive recursive functions to be given
  4043 directly (as in HOL) over datatypes and the natural numbers;
  4044 
  4045 * new tactics induct_tac and exhaust_tac for induction (or case
  4046 analysis) over datatypes and the natural numbers;
  4047 
  4048 * the datatype declaration of type T now defines the recursor T_rec;
  4049 
  4050 * simplification automatically does freeness reasoning for datatype
  4051 constructors;
  4052 
  4053 * automatic type-inference, with AddTCs command to insert new
  4054 type-checking rules;
  4055 
  4056 * datatype introduction rules are now added as Safe Introduction rules
  4057 to the claset;
  4058 
  4059 * the syntax "if P then x else y" is now available in addition to
  4060 if(P,x,y);
  4061 
  4062 
  4063 *** Internal programming interfaces ***
  4064 
  4065 * tuned simplifier trace output; new flag debug_simp;
  4066 
  4067 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4068 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4069 
  4070 * AxClass.axclass_tac lost the theory argument;
  4071 
  4072 * tuned current_goals_markers semantics: begin / end goal avoids
  4073 printing empty lines;
  4074 
  4075 * removed prs and prs_fn hook, which was broken because it did not
  4076 include \n in its semantics, forcing writeln to add one
  4077 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4078 string -> unit if you really want to output text without newline;
  4079 
  4080 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4081 plain output, interface builders may have to enable 'isabelle_font'
  4082 mode to get Isabelle font glyphs as before;
  4083 
  4084 * refined token_translation interface; INCOMPATIBILITY: output length
  4085 now of type real instead of int;
  4086 
  4087 * theory loader actions may be traced via new ThyInfo.add_hook
  4088 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4089 your own database of information attached to *whole* theories -- as
  4090 opposed to intra-theory data slots offered via TheoryDataFun;
  4091 
  4092 * proper handling of dangling sort hypotheses (at last!);
  4093 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4094 extra sort hypotheses that can be witnessed from the type signature;
  4095 the force_strip_shyps flag is gone, any remaining shyps are simply
  4096 left in the theorem (with a warning issued by strip_shyps_warning);
  4097 
  4098 
  4099 
  4100 New in Isabelle98-1 (October 1998)
  4101 ----------------------------------
  4102 
  4103 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4104 
  4105 * several changes of automated proof tools;
  4106 
  4107 * HOL: major changes to the inductive and datatype packages, including
  4108 some minor incompatibilities of theory syntax;
  4109 
  4110 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4111 called `inj_on';
  4112 
  4113 * HOL: removed duplicate thms in Arith:
  4114   less_imp_add_less  should be replaced by  trans_less_add1
  4115   le_imp_add_le      should be replaced by  trans_le_add1
  4116 
  4117 * HOL: unary minus is now overloaded (new type constraints may be
  4118 required);
  4119 
  4120 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4121 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4122 now taken as an integer constant.
  4123 
  4124 * Pure: ML function 'theory_of' renamed to 'theory';
  4125 
  4126 
  4127 *** Proof tools ***
  4128 
  4129 * Simplifier:
  4130   1. Asm_full_simp_tac is now more aggressive.
  4131      1. It will sometimes reorient premises if that increases their power to
  4132         simplify.
  4133      2. It does no longer proceed strictly from left to right but may also
  4134         rotate premises to achieve further simplification.
  4135      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4136      old Asm_full_simp_tac in that it does not rotate premises.
  4137   2. The simplifier now knows a little bit about nat-arithmetic.
  4138 
  4139 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4140 allows for selected deletion of wrappers, by introduction of names for
  4141 wrapper functionals.  This implies that addbefore, addSbefore,
  4142 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4143 and that adding two tactics with the same name overwrites the first
  4144 one (emitting a warning).
  4145   type wrapper = (int -> tactic) -> (int -> tactic)
  4146   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4147   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4148   delWrapper, delSWrapper: claset *  string            -> claset
  4149   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4150 
  4151 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4152 semantics; addbefore now affects only the unsafe part of step_tac
  4153 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4154 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4155 by Force_tac;
  4156 
  4157 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4158 compWrapper; added safe wrapper (and access functions for it);
  4159 
  4160 * HOL/split_all_tac is now much faster and fails if there is nothing
  4161 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4162 and the names of the automatically generated variables have changed.
  4163 split_all_tac has moved within claset() from unsafe wrappers to safe
  4164 wrappers, which means that !!-bound variables are split much more
  4165 aggressively, and safe_tac and clarify_tac now split such variables.
  4166 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4167 Note: the same holds for record_split_tac, which does the job of
  4168 split_all_tac for record fields.
  4169 
  4170 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4171 permanently to the default simpset using Addsplits just like
  4172 Addsimps. They can be removed via Delsplits just like
  4173 Delsimps. Lower-case versions are also available.
  4174 
  4175 * HOL/Simplifier: The rule split_if is now part of the default
  4176 simpset. This means that the simplifier will eliminate all occurrences
  4177 of if-then-else in the conclusion of a goal. To prevent this, you can
  4178 either remove split_if completely from the default simpset by
  4179 `Delsplits [split_if]' or remove it in a specific call of the
  4180 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4181 other case splitting rules to/from the default simpset: every datatype
  4182 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4183 t is the name of the datatype).
  4184 
  4185 * Classical reasoner / Simplifier combination: new force_tac (and
  4186 derivatives Force_tac, force) combines rewriting and classical
  4187 reasoning (and whatever other tools) similarly to auto_tac, but is
  4188 aimed to solve the given subgoal completely.
  4189 
  4190 
  4191 *** General ***
  4192 
  4193 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4194 and `goalw': the theory is no longer needed as an explicit argument -
  4195 the current theory context is used; assumptions are no longer returned
  4196 at the ML-level unless one of them starts with ==> or !!; it is
  4197 recommended to convert to these new commands using isatool fixgoal
  4198 (backup your sources first!);
  4199 
  4200 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4201 the current theory context, and 'theory' to lookup stored theories;
  4202 
  4203 * new theory section 'locale' for declaring constants, assumptions and
  4204 definitions that have local scope;
  4205 
  4206 * new theory section 'nonterminals' for purely syntactic types;
  4207 
  4208 * new theory section 'setup' for generic ML setup functions
  4209 (e.g. package initialization);
  4210 
  4211 * the distribution now includes Isabelle icons: see
  4212 lib/logo/isabelle-{small,tiny}.xpm;
  4213 
  4214 * isatool install - install binaries with absolute references to
  4215 ISABELLE_HOME/bin;
  4216 
  4217 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4218 
  4219 * print mode 'emacs' reserved for Isamode;
  4220 
  4221 * support multiple print (ast) translations per constant name;
  4222 
  4223 * theorems involving oracles are now printed with a suffixed [!];
  4224 
  4225 
  4226 *** HOL ***
  4227 
  4228 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4229 
  4230 * HOL/inductive package reorganized and improved: now supports mutual
  4231 definitions such as
  4232 
  4233   inductive EVEN ODD
  4234     intrs
  4235       null "0 : EVEN"
  4236       oddI "n : EVEN ==> Suc n : ODD"
  4237       evenI "n : ODD ==> Suc n : EVEN"
  4238 
  4239 new theorem list "elims" contains an elimination rule for each of the
  4240 recursive sets; inductive definitions now handle disjunctive premises
  4241 correctly (also ZF);
  4242 
  4243 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4244 "mutual_induct" no longer exists - the induction rule is always
  4245 contained in "induct";
  4246 
  4247 
  4248 * HOL/datatype package re-implemented and greatly improved: now
  4249 supports mutually recursive datatypes such as
  4250 
  4251   datatype
  4252     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4253             | SUM ('a aexp) ('a aexp)
  4254             | DIFF ('a aexp) ('a aexp)
  4255             | NUM 'a
  4256   and
  4257     'a bexp = LESS ('a aexp) ('a aexp)
  4258             | AND ('a bexp) ('a bexp)
  4259             | OR ('a bexp) ('a bexp)
  4260 
  4261 as well as indirectly recursive datatypes such as
  4262 
  4263   datatype
  4264     ('a, 'b) term = Var 'a
  4265                   | App 'b ((('a, 'b) term) list)
  4266 
  4267 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4268 induction on mutually / indirectly recursive datatypes.
  4269 
  4270 Primrec equations are now stored in theory and can be accessed via
  4271 <function_name>.simps.
  4272 
  4273 INCOMPATIBILITIES:
  4274 
  4275   - Theories using datatypes must now have theory Datatype as an
  4276     ancestor.
  4277   - The specific <typename>.induct_tac no longer exists - use the
  4278     generic induct_tac instead.
  4279   - natE has been renamed to nat.exhaust - use exhaust_tac
  4280     instead of res_inst_tac ... natE. Note that the variable
  4281     names in nat.exhaust differ from the names in natE, this
  4282     may cause some "fragile" proofs to fail.
  4283   - The theorems split_<typename>_case and split_<typename>_case_asm
  4284     have been renamed to <typename>.split and <typename>.split_asm.
  4285   - Since default sorts of type variables are now handled correctly,
  4286     some datatype definitions may have to be annotated with explicit
  4287     sort constraints.
  4288   - Primrec definitions no longer require function name and type
  4289     of recursive argument.
  4290 
  4291 Consider using isatool fixdatatype to adapt your theories and proof
  4292 scripts to the new package (backup your sources first!).
  4293 
  4294 
  4295 * HOL/record package: considerably improved implementation; now
  4296 includes concrete syntax for record types, terms, updates; theorems
  4297 for surjective pairing and splitting !!-bound record variables; proof
  4298 support is as follows:
  4299 
  4300   1) standard conversions (selectors or updates applied to record
  4301 constructor terms) are part of the standard simpset;
  4302 
  4303   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4304 made part of standard simpset and claset via addIffs;
  4305 
  4306   3) a tactic for record field splitting (record_split_tac) is part of
  4307 the standard claset (addSWrapper);
  4308 
  4309 To get a better idea about these rules you may retrieve them via
  4310 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4311 the name of your record type.
  4312 
  4313 The split tactic 3) conceptually simplifies by the following rule:
  4314 
  4315   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4316 
  4317 Thus any record variable that is bound by meta-all will automatically
  4318 blow up into some record constructor term, consequently the
  4319 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4320 solve record problems automatically.
  4321 
  4322 
  4323 * reorganized the main HOL image: HOL/Integ and String loaded by
  4324 default; theory Main includes everything;
  4325 
  4326 * automatic simplification of integer sums and comparisons, using cancellation;
  4327 
  4328 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4329 
  4330 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4331 
  4332 * many new identities for unions, intersections, set difference, etc.;
  4333 
  4334 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4335 called split_if, split_split, split_sum_case and split_nat_case (to go
  4336 with add/delsplits);
  4337 
  4338 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4339 (?x::unit) = (); this is made part of the default simpset, which COULD
  4340 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4341 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4342 unit_abs_eta_conv is added in order to counter the effect of
  4343 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4344 %u.f();
  4345 
  4346 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4347 makes more sense);
  4348 
  4349 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4350   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4351   disjointness reasoning but breaking a few old proofs.
  4352 
  4353 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4354 to 'converse' from 'inverse' (for compatibility with ZF and some
  4355 literature);
  4356 
  4357 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4358 the well-founded relation;
  4359 
  4360 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4361     Compl A.  The "Compl" syntax remains available as input syntax for this
  4362     release ONLY.
  4363 
  4364 * HOL/Update: new theory of function updates:
  4365     f(a:=b) == %x. if x=a then b else f x
  4366 may also be iterated as in f(a:=b,c:=d,...);
  4367 
  4368 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4369 
  4370 * HOL/List:
  4371   - new function list_update written xs[i:=v] that updates the i-th
  4372     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4373   - new function `upt' written [i..j(] which generates the list
  4374     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4375     bound write [i..j], which is a shorthand for [i..j+1(].
  4376   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4377 
  4378 * HOL/Arith:
  4379   - removed 'pred' (predecessor) function;
  4380   - generalized some theorems about n-1;
  4381   - many new laws about "div" and "mod";
  4382   - new laws about greatest common divisors (see theory ex/Primes);
  4383 
  4384 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4385 instead of "inverse";
  4386 
  4387 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4388   of the multiset ordering;
  4389 
  4390 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4391   (not included by default);
  4392 
  4393 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4394 
  4395 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4396   programs, i.e. different program variables may have different types.
  4397 
  4398 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4399   [previously, this check worked only if the rewrite rule was unconditional]
  4400   Now rew can involve either definitions or equalities (either == or =).
  4401 
  4402 
  4403 *** ZF ***
  4404 
  4405 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4406   only the theorems proved on ZF.ML;
  4407 
  4408 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4409   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4410   disjointness reasoning but breaking a few old proofs.
  4411 
  4412 * ZF/Update: new theory of function updates
  4413     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4414   may also be iterated as in f(a:=b,c:=d,...);
  4415 
  4416 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4417 
  4418 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4419   [previously, this check worked only if the rewrite rule was unconditional]
  4420   Now rew can involve either definitions or equalities (either == or =).
  4421 
  4422 * case_tac provided for compatibility with HOL
  4423     (like the old excluded_middle_tac, but with subgoals swapped)
  4424 
  4425 
  4426 *** Internal programming interfaces ***
  4427 
  4428 * Pure: several new basic modules made available for general use, see
  4429 also src/Pure/README;
  4430 
  4431 * improved the theory data mechanism to support encapsulation (data
  4432 kind name replaced by private Object.kind, acting as authorization
  4433 key); new type-safe user interface via functor TheoryDataFun; generic
  4434 print_data function becomes basically useless;
  4435 
  4436 * removed global_names compatibility flag -- all theory declarations
  4437 are qualified by default;
  4438 
  4439 * module Pure/Syntax now offers quote / antiquote translation
  4440 functions (useful for Hoare logic etc. with implicit dependencies);
  4441 see HOL/ex/Antiquote for an example use;
  4442 
  4443 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4444 cterm -> thm;
  4445 
  4446 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4447 subgoal;
  4448 
  4449 * Display.print_goals function moved to Locale.print_goals;
  4450 
  4451 * standard print function for goals supports current_goals_markers
  4452 variable for marking begin of proof, end of proof, start of goal; the
  4453 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4454 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4455 for example;
  4456 
  4457 
  4458 
  4459 New in Isabelle98 (January 1998)
  4460 --------------------------------
  4461 
  4462 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4463 
  4464 * changed lexical syntax of terms / types: dots made part of long
  4465 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4466 
  4467 * simpset (and claset) reference variable replaced by functions
  4468 simpset / simpset_ref;
  4469 
  4470 * no longer supports theory aliases (via merge) and non-trivial
  4471 implicit merge of thms' signatures;
  4472 
  4473 * most internal names of constants changed due to qualified names;
  4474 
  4475 * changed Pure/Sequence interface (see Pure/seq.ML);
  4476 
  4477 
  4478 *** General Changes ***
  4479 
  4480 * hierachically structured name spaces (for consts, types, axms, thms
  4481 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4482 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4483 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4484 long_names for fully qualified output names; NOTE: ML programs
  4485 (special tactics, packages etc.) referring to internal names may have
  4486 to be adapted to cope with fully qualified names; in case of severe
  4487 backward campatibility problems try setting 'global_names' at compile
  4488 time to have enrything declared within a flat name space; one may also
  4489 fine tune name declarations in theories via the 'global' and 'local'
  4490 section;
  4491 
  4492 * reimplemented the implicit simpset and claset using the new anytype
  4493 data filed in signatures; references simpset:simpset ref etc. are
  4494 replaced by functions simpset:unit->simpset and
  4495 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4496 to patch your ML files accordingly;
  4497 
  4498 * HTML output now includes theory graph data for display with Java
  4499 applet or isatool browser; data generated automatically via isatool
  4500 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4501 
  4502 * defs may now be conditional; improved rewrite_goals_tac to handle
  4503 conditional equations;
  4504 
  4505 * defs now admits additional type arguments, using TYPE('a) syntax;
  4506 
  4507 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4508 creates a new theory node; implicit merge of thms' signatures is
  4509 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4510 transfer:theory->thm->thm in (rare) cases;
  4511 
  4512 * improved handling of draft signatures / theories; draft thms (and
  4513 ctyps, cterms) are automatically promoted to real ones;
  4514 
  4515 * slightly changed interfaces for oracles: admit many per theory, named
  4516 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4517 
  4518 * print_goals: optional output of const types (set show_consts and
  4519 show_types);
  4520 
  4521 * improved output of warnings (###) and errors (***);
  4522 
  4523 * subgoal_tac displays a warning if the new subgoal has type variables;
  4524 
  4525 * removed old README and Makefiles;
  4526 
  4527 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4528 
  4529 * removed obsolete init_pps and init_database;
  4530 
  4531 * deleted the obsolete tactical STATE, which was declared by
  4532     fun STATE tacfun st = tacfun st st;
  4533 
  4534 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4535 (which abbreviates $HOME);
  4536 
  4537 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4538 use isatool fixseq to adapt your ML programs (this works for fully
  4539 qualified references to the Sequence structure only!);
  4540 
  4541 * use_thy no longer requires writable current directory; it always
  4542 reloads .ML *and* .thy file, if either one is out of date;
  4543 
  4544 
  4545 *** Classical Reasoner ***
  4546 
  4547 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4548 tactics that use classical reasoning to simplify a subgoal without
  4549 splitting it into several subgoals;
  4550 
  4551 * Safe_tac: like safe_tac but uses the default claset;
  4552 
  4553 
  4554 *** Simplifier ***
  4555 
  4556 * added simplification meta rules:
  4557     (asm_)(full_)simplify: simpset -> thm -> thm;
  4558 
  4559 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4560 logics (again);
  4561 
  4562 * added prems argument to simplification procedures;
  4563 
  4564 * HOL, FOL, ZF: added infix function `addsplits':
  4565   instead of `<simpset> setloop (split_tac <thms>)'
  4566   you can simply write `<simpset> addsplits <thms>'
  4567 
  4568 
  4569 *** Syntax ***
  4570 
  4571 * TYPE('a) syntax for type reflection terms;
  4572 
  4573 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4574 
  4575 * pretty printer: changed order of mixfix annotation preference (again!);
  4576 
  4577 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4578 
  4579 
  4580 *** HOL ***
  4581 
  4582 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4583   with `addloop' of the simplifier to faciliate case splitting in premises.
  4584 
  4585 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4586 
  4587 * HOL/Auth: new protocol proofs including some for the Internet
  4588   protocol TLS;
  4589 
  4590 * HOL/Map: new theory of `maps' a la VDM;
  4591 
  4592 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4593 cancelling out common nat summands from =, <, <= (in)equalities, or
  4594 differences; simplification procedures nat_cancel_factor for
  4595 cancelling common factor from =, <, <= (in)equalities over natural
  4596 sums; nat_cancel contains both kinds of procedures, it is installed by
  4597 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4598 
  4599 * HOL/simplifier: terms of the form
  4600   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4601   are rewritten to
  4602   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4603   and those of the form
  4604   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4605   are rewritten to
  4606   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4607 
  4608 * HOL/datatype
  4609   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4610 
  4611   P(t_case f1 ... fn x) =
  4612      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4613         ...
  4614        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4615      )
  4616 
  4617   and a theorem `split_t_case_asm' of the form
  4618 
  4619   P(t_case f1 ... fn x) =
  4620     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4621         ...
  4622        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4623      )
  4624   which can be added to a simpset via `addsplits'. The existing theorems
  4625   expand_list_case and expand_option_case have been renamed to
  4626   split_list_case and split_option_case.
  4627 
  4628 * HOL/Arithmetic:
  4629   - `pred n' is automatically converted to `n-1'.
  4630     Users are strongly encouraged not to use `pred' any longer,
  4631     because it will disappear altogether at some point.
  4632   - Users are strongly encouraged to write "0 < n" rather than
  4633     "n ~= 0". Theorems and proof tools have been modified towards this
  4634     `standard'.
  4635 
  4636 * HOL/Lists:
  4637   the function "set_of_list" has been renamed "set" (and its theorems too);
  4638   the function "nth" now takes its arguments in the reverse order and
  4639   has acquired the infix notation "!" as in "xs!n".
  4640 
  4641 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4642 
  4643 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4644   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4645 
  4646 * HOL/record: extensible records with schematic structural subtyping
  4647 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4648 still lacks various theorems and concrete record syntax;
  4649 
  4650 
  4651 *** HOLCF ***
  4652 
  4653 * removed "axioms" and "generated by" sections;
  4654 
  4655 * replaced "ops" section by extended "consts" section, which is capable of
  4656   handling the continuous function space "->" directly;
  4657 
  4658 * domain package:
  4659   . proves theorems immediately and stores them in the theory,
  4660   . creates hierachical name space,
  4661   . now uses normal mixfix annotations (instead of cinfix...),
  4662   . minor changes to some names and values (for consistency),
  4663   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4664   . separator between mutual domain defs: changed "," to "and",
  4665   . improved handling of sort constraints;  now they have to
  4666     appear on the left-hand side of the equations only;
  4667 
  4668 * fixed LAM <x,y,zs>.b syntax;
  4669 
  4670 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4671 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4672 
  4673 
  4674 *** FOL and ZF ***
  4675 
  4676 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4677   with `addloop' of the simplifier to faciliate case splitting in premises.
  4678 
  4679 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4680 in HOL, they strip ALL and --> from proved theorems;
  4681 
  4682 
  4683 
  4684 New in Isabelle94-8 (May 1997)
  4685 ------------------------------
  4686 
  4687 *** General Changes ***
  4688 
  4689 * new utilities to build / run / maintain Isabelle etc. (in parts
  4690 still somewhat experimental); old Makefiles etc. still functional;
  4691 
  4692 * new 'Isabelle System Manual';
  4693 
  4694 * INSTALL text, together with ./configure and ./build scripts;
  4695 
  4696 * reimplemented type inference for greater efficiency, better error
  4697 messages and clean internal interface;
  4698 
  4699 * prlim command for dealing with lots of subgoals (an easier way of
  4700 setting goals_limit);
  4701 
  4702 
  4703 *** Syntax ***
  4704 
  4705 * supports alternative (named) syntax tables (parser and pretty
  4706 printer); internal interface is provided by add_modesyntax(_i);
  4707 
  4708 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4709 be used in conjunction with the Isabelle symbol font; uses the
  4710 "symbols" syntax table;
  4711 
  4712 * added token_translation interface (may translate name tokens in
  4713 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4714 the current print_mode); IMPORTANT: user print translation functions
  4715 are responsible for marking newly introduced bounds
  4716 (Syntax.mark_boundT);
  4717 
  4718 * token translations for modes "xterm" and "xterm_color" that display
  4719 names in bold, underline etc. or colors (which requires a color
  4720 version of xterm);
  4721 
  4722 * infixes may now be declared with names independent of their syntax;
  4723 
  4724 * added typed_print_translation (like print_translation, but may
  4725 access type of constant);
  4726 
  4727 
  4728 *** Classical Reasoner ***
  4729 
  4730 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4731 some limitations.  Blast_tac...
  4732   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4733   + ignores elimination rules that don't have the correct format
  4734         (the conclusion MUST be a formula variable)
  4735   + ignores types, which can make HOL proofs fail
  4736   + rules must not require higher-order unification, e.g. apply_type in ZF
  4737     [message "Function Var's argument not a bound variable" relates to this]
  4738   + its proof strategy is more general but can actually be slower
  4739 
  4740 * substitution with equality assumptions no longer permutes other
  4741 assumptions;
  4742 
  4743 * minor changes in semantics of addafter (now called addaltern); renamed
  4744 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4745 (and access functions for it);
  4746 
  4747 * improved combination of classical reasoner and simplifier:
  4748   + functions for handling clasimpsets
  4749   + improvement of addss: now the simplifier is called _after_ the
  4750     safe steps.
  4751   + safe variant of addss called addSss: uses safe simplifications
  4752     _during_ the safe steps. It is more complete as it allows multiple
  4753     instantiations of unknowns (e.g. with slow_tac).
  4754 
  4755 *** Simplifier ***
  4756 
  4757 * added interface for simplification procedures (functions that
  4758 produce *proven* rewrite rules on the fly, depending on current
  4759 redex);
  4760 
  4761 * ordering on terms as parameter (used for ordered rewriting);
  4762 
  4763 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4764 
  4765 * the solver is now split into a safe and an unsafe part.
  4766 This should be invisible for the normal user, except that the
  4767 functions setsolver and addsolver have been renamed to setSolver and
  4768 addSolver; added safe_asm_full_simp_tac;
  4769 
  4770 
  4771 *** HOL ***
  4772 
  4773 * a generic induction tactic `induct_tac' which works for all datatypes and
  4774 also for type `nat';
  4775 
  4776 * a generic case distinction tactic `exhaust_tac' which works for all
  4777 datatypes and also for type `nat';
  4778 
  4779 * each datatype comes with a function `size';
  4780 
  4781 * patterns in case expressions allow tuple patterns as arguments to
  4782 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4783 
  4784 * primrec now also works with type nat;
  4785 
  4786 * recdef: a new declaration form, allows general recursive functions to be
  4787 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4788 
  4789 * the constant for negation has been renamed from "not" to "Not" to
  4790 harmonize with FOL, ZF, LK, etc.;
  4791 
  4792 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4793 infinite lists;
  4794 
  4795 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4796 
  4797 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4798 problems in commutative rings, using axiomatic type classes for + and *;
  4799 
  4800 * more examples in HOL/MiniML and HOL/Auth;
  4801 
  4802 * more default rewrite rules for quantifiers, union/intersection;
  4803 
  4804 * a new constant `arbitrary == @x.False';
  4805 
  4806 * HOLCF/IOA replaces old HOL/IOA;
  4807 
  4808 * HOLCF changes: derived all rules and arities
  4809   + axiomatic type classes instead of classes
  4810   + typedef instead of faking type definitions
  4811   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4812   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4813   + eliminated the types void, one, tr
  4814   + use unit lift and bool lift (with translations) instead of one and tr
  4815   + eliminated blift from Lift3.thy (use Def instead of blift)
  4816   all eliminated rules are derived as theorems --> no visible changes ;
  4817 
  4818 
  4819 *** ZF ***
  4820 
  4821 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4822 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4823 as ZF_cs addSIs [equalityI];
  4824 
  4825 
  4826 
  4827 New in Isabelle94-7 (November 96)
  4828 ---------------------------------
  4829 
  4830 * allowing negative levels (as offsets) in prlev and choplev;
  4831 
  4832 * super-linear speedup for large simplifications;
  4833 
  4834 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4835 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4836 FAIL); can suppress it using the command Delsimps (ex_simps @
  4837 all_simps); De Morgan laws are also now included, by default;
  4838 
  4839 * improved printing of ==>  :  ~:
  4840 
  4841 * new object-logic "Sequents" adds linear logic, while replacing LK
  4842 and Modal (thanks to Sara Kalvala);
  4843 
  4844 * HOL/Auth: correctness proofs for authentication protocols;
  4845 
  4846 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4847 examples on HOL/Auth);
  4848 
  4849 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4850 the rewriter and classical reasoner simultaneously;
  4851 
  4852 * function uresult no longer returns theorems in "standard" format;
  4853 regain previous version by: val uresult = standard o uresult;
  4854 
  4855 
  4856 
  4857 New in Isabelle94-6
  4858 -------------------
  4859 
  4860 * oracles -- these establish an interface between Isabelle and trusted
  4861 external reasoners, which may deliver results as theorems;
  4862 
  4863 * proof objects (in particular record all uses of oracles);
  4864 
  4865 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4866 
  4867 * "constdefs" section in theory files;
  4868 
  4869 * "primrec" section (HOL) no longer requires names;
  4870 
  4871 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4872 
  4873 
  4874 
  4875 New in Isabelle94-5
  4876 -------------------
  4877 
  4878 * reduced space requirements;
  4879 
  4880 * automatic HTML generation from theories;
  4881 
  4882 * theory files no longer require "..." (quotes) around most types;
  4883 
  4884 * new examples, including two proofs of the Church-Rosser theorem;
  4885 
  4886 * non-curried (1994) version of HOL is no longer distributed;
  4887 
  4888 
  4889 
  4890 New in Isabelle94-4
  4891 -------------------
  4892 
  4893 * greatly reduced space requirements;
  4894 
  4895 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4896 
  4897 * searchable theorem database (see the section "Retrieving theorems" on
  4898 page 8 of the Reference Manual);
  4899 
  4900 * new examples, including Grabczewski's monumental case study of the
  4901 Axiom of Choice;
  4902 
  4903 * The previous version of HOL renamed to Old_HOL;
  4904 
  4905 * The new version of HOL (previously called CHOL) uses a curried syntax
  4906 for functions.  Application looks like f a b instead of f(a,b);
  4907 
  4908 * Mutually recursive inductive definitions finally work in HOL;
  4909 
  4910 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4911 translates to the operator "split";
  4912 
  4913 
  4914 
  4915 New in Isabelle94-3
  4916 -------------------
  4917 
  4918 * new infix operator, addss, allowing the classical reasoner to
  4919 perform simplification at each step of its search.  Example:
  4920         fast_tac (cs addss ss)
  4921 
  4922 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4923 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4924 look like (a,b) instead of <a,b>;
  4925 
  4926 * PLEASE NOTE: CHOL will eventually replace HOL!
  4927 
  4928 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4929 It translates to the operator "split".  A new theory of integers is available;
  4930 
  4931 * In ZF, integer numerals now denote two's-complement binary integers.
  4932 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4933 
  4934 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4935 of the Axiom of Choice;
  4936 
  4937 
  4938 
  4939 New in Isabelle94-2
  4940 -------------------
  4941 
  4942 * Significantly faster resolution;
  4943 
  4944 * the different sections in a .thy file can now be mixed and repeated
  4945 freely;
  4946 
  4947 * Database of theorems for FOL, HOL and ZF.  New
  4948 commands including qed, qed_goal and bind_thm store theorems in the database.
  4949 
  4950 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4951 a given theory (thms_of), or find out what theory a theorem was proved in
  4952 (theory_of_thm);
  4953 
  4954 * Bugs fixed in the inductive definition and datatype packages;
  4955 
  4956 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4957 and HOL_dup_cs obsolete;
  4958 
  4959 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4960 have been removed;
  4961 
  4962 * Simpler definition of function space in ZF;
  4963 
  4964 * new results about cardinal and ordinal arithmetic in ZF;
  4965 
  4966 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4967 types;
  4968 
  4969 
  4970 $Id$