NEWS
author nipkow
Wed Jul 04 14:21:00 2007 +0200 (2007-07-04)
changeset 23565 c00b12a4e245
parent 23564 ae0e735fbec8
child 23783 e4d514f81d95
permissions -rw-r--r--
*** empty log message ***
     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)> (SML #)
    94     writing SML code to a file:
    95         code_gen <list of constants (term syntax)> (SML <filename>)
    96     writing OCaml code to a file:
    97         code_gen <list of constants (term syntax)> (OCaml <filename>)
    98     writing Haskell code to a bunch of files:
    99         code_gen <list of constants (term syntax)> (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 * Method "metis" proves goals by applying the Metis general-purpose
   545 resolution prover.  Examples are in the directory MetisExamples.  See
   546 also http://gilith.com/software/metis/
   547   
   548 * Command 'sledgehammer' invokes external automatic theorem provers as
   549 background processes.  It generates calls to the "metis" method if
   550 successful. These can be pasted into the proof.  Users do not have to
   551 wait for the automatic provers to return.
   552 
   553 * Case-expressions allow arbitrary constructor-patterns (including "_") and
   554   take their order into account, like in functional programming.
   555   Internally, this is translated into nested case-expressions; missing cases
   556   are added and mapped to the predefined constant "undefined". In complicated
   557   cases printing may no longer show the original input but the internal
   558   form. Lambda-abstractions allow the same form of pattern matching:
   559   "% pat1 => e1 | ..." is an abbreviation for
   560   "%x. case x of pat1 => e1 | ..." where x is a new variable.
   561 
   562 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   563   is an abbreviation for "of_nat :: nat => int". The simplification rules
   564   for "of_nat" have been changed to work like "int" did previously.
   565   (potential INCOMPATIBILITY)
   566   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   567   - of_nat_diff and of_nat_mult are no longer default simp rules
   568 
   569 * Method "algebra" solves polynomial equations over (semi)rings using
   570   Groebner bases. The (semi)ring structure is defined by locales and
   571   the tool setup depends on that generic context. Installing the
   572   method for a specific type involves instantiating the locale and
   573   possibly adding declarations for computation on the coefficients.
   574   The method is already instantiated for natural numbers and for the
   575   axiomatic class of idoms with numerals.  See also the paper by
   576   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   577   underlying this architecture of context-aware proof-tools.
   578 
   579 * constant "List.op @" now named "List.append".  Use ML antiquotations
   580 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   581 possible incompatibilities when working on ML level.
   582 
   583 * Constant renames due to introduction of canonical name prefixing for
   584   class package:
   585 
   586     HOL.abs ~> HOL.minus_class.abs
   587     HOL.divide ~> HOL.divide_class.divide
   588     Nat.power ~> Nat.power_class.power
   589     Nat.size ~> Nat.size_class.size
   590     Numeral.number_of ~> Numeral.number_class.number_of
   591     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   592 
   593 * Rudimentary class target mechanism involves constant renames:
   594 
   595     Orderings.min ~> Orderings.ord_class.min
   596     Orderings.max ~> Orderings.ord_class.max
   597     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   598 
   599 * primrec: missing cases mapped to "undefined" instead of "arbitrary"
   600 
   601 * new constant "undefined" with axiom "undefined x = undefined"
   602 
   603 * new class "default" with associated constant "default"
   604 
   605 * new function listsum :: 'a list => 'a for arbitrary monoids.
   606   Special syntax: "SUM x <- xs. f x" (and latex variants)
   607 
   608 * new (input only) syntax for Haskell-like list comprehension, eg
   609   [(x,y). x <- xs, y <- ys, x ~= y]
   610   For details see List.thy.
   611 
   612 * The special syntax for function "filter" has changed from [x : xs. P] to
   613   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   614   and for uniformity. INCOMPATIBILITY
   615 
   616 * New lemma collection field_simps (an extension of ring_simps)
   617   for manipulating (in)equations involving division. Multiplies
   618   with all denominators that can be proved to be non-zero (in equations)
   619   or positive/negative (in inequations).
   620 
   621 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   622   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   623   Removed lemmas field_xyz in Ring_and_Field
   624   because they were subsumed by lemmas xyz.
   625 INCOMPATIBILITY.
   626 
   627 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   628   when generating code.
   629 
   630 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   631   when generating code.
   632 
   633 * Library/Commutative_Ring.thy: switched from recdef to function package;
   634   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   635 
   636 * Some steps towards more uniform lattice theory development in HOL.
   637 
   638     constants "meet" and "join" now named "inf" and "sup"
   639     constant "Meet" now named "Inf"
   640 
   641     classes "meet_semilorder" and "join_semilorder" now named
   642       "lower_semilattice" and "upper_semilattice"
   643     class "lorder" now named "lattice"
   644     class "comp_lat" now named "complete_lattice"
   645 
   646     Instantiation of lattice classes allows explicit definitions
   647     for "inf" and "sup" operations.
   648 
   649   INCOMPATIBILITY.  Theorem renames:
   650 
   651     meet_left_le            ~> inf_le1
   652     meet_right_le           ~> inf_le2
   653     join_left_le            ~> sup_ge1
   654     join_right_le           ~> sup_ge2
   655     meet_join_le            ~> inf_sup_ord
   656     le_meetI                ~> le_infI
   657     join_leI                ~> le_supI
   658     le_meet                 ~> le_inf_iff
   659     le_join                 ~> ge_sup_conv
   660     meet_idempotent         ~> inf_idem
   661     join_idempotent         ~> sup_idem
   662     meet_comm               ~> inf_commute
   663     join_comm               ~> sup_commute
   664     meet_leI1               ~> le_infI1
   665     meet_leI2               ~> le_infI2
   666     le_joinI1               ~> le_supI1
   667     le_joinI2               ~> le_supI2
   668     meet_assoc              ~> inf_assoc
   669     join_assoc              ~> sup_assoc
   670     meet_left_comm          ~> inf_left_commute
   671     meet_left_idempotent    ~> inf_left_idem
   672     join_left_comm          ~> sup_left_commute
   673     join_left_idempotent    ~> sup_left_idem
   674     meet_aci                ~> inf_aci
   675     join_aci                ~> sup_aci
   676     le_def_meet             ~> le_iff_inf
   677     le_def_join             ~> le_iff_sup
   678     join_absorp2            ~> sup_absorb2
   679     join_absorp1            ~> sup_absorb1
   680     meet_absorp1            ~> inf_absorb1
   681     meet_absorp2            ~> inf_absorb2
   682     meet_join_absorp        ~> inf_sup_absorb
   683     join_meet_absorp        ~> sup_inf_absorb
   684     distrib_join_le         ~> distrib_sup_le
   685     distrib_meet_le         ~> distrib_inf_le
   686 
   687     add_meet_distrib_left   ~> add_inf_distrib_left
   688     add_join_distrib_left   ~> add_sup_distrib_left
   689     is_join_neg_meet        ~> is_join_neg_inf
   690     is_meet_neg_join        ~> is_meet_neg_sup
   691     add_meet_distrib_right  ~> add_inf_distrib_right
   692     add_join_distrib_right  ~> add_sup_distrib_right
   693     add_meet_join_distribs  ~> add_sup_inf_distribs
   694     join_eq_neg_meet        ~> sup_eq_neg_inf
   695     meet_eq_neg_join        ~> inf_eq_neg_sup
   696     add_eq_meet_join        ~> add_eq_inf_sup
   697     meet_0_imp_0            ~> inf_0_imp_0
   698     join_0_imp_0            ~> sup_0_imp_0
   699     meet_0_eq_0             ~> inf_0_eq_0
   700     join_0_eq_0             ~> sup_0_eq_0
   701     neg_meet_eq_join        ~> neg_inf_eq_sup
   702     neg_join_eq_meet        ~> neg_sup_eq_inf
   703     join_eq_if              ~> sup_eq_if
   704 
   705     mono_meet               ~> mono_inf
   706     mono_join               ~> mono_sup
   707     meet_bool_eq            ~> inf_bool_eq
   708     join_bool_eq            ~> sup_bool_eq
   709     meet_fun_eq             ~> inf_fun_eq
   710     join_fun_eq             ~> sup_fun_eq
   711     meet_set_eq             ~> inf_set_eq
   712     join_set_eq             ~> sup_set_eq
   713     meet1_iff               ~> inf1_iff
   714     meet2_iff               ~> inf2_iff
   715     meet1I                  ~> inf1I
   716     meet2I                  ~> inf2I
   717     meet1D1                 ~> inf1D1
   718     meet2D1                 ~> inf2D1
   719     meet1D2                 ~> inf1D2
   720     meet2D2                 ~> inf2D2
   721     meet1E                  ~> inf1E
   722     meet2E                  ~> inf2E
   723     join1_iff               ~> sup1_iff
   724     join2_iff               ~> sup2_iff
   725     join1I1                 ~> sup1I1
   726     join2I1                 ~> sup2I1
   727     join1I1                 ~> sup1I1
   728     join2I2                 ~> sup1I2
   729     join1CI                 ~> sup1CI
   730     join2CI                 ~> sup2CI
   731     join1E                  ~> sup1E
   732     join2E                  ~> sup2E
   733 
   734     is_meet_Meet            ~> is_meet_Inf
   735     Meet_bool_def           ~> Inf_bool_def
   736     Meet_fun_def            ~> Inf_fun_def
   737     Meet_greatest           ~> Inf_greatest
   738     Meet_lower              ~> Inf_lower
   739     Meet_set_def            ~> Inf_set_def
   740 
   741     listsp_meetI            ~> listsp_infI
   742     listsp_meet_eq          ~> listsp_inf_eq
   743 
   744     meet_min                ~> inf_min
   745     join_max                ~> sup_max
   746 
   747 * Classes "order" and "linorder": facts "refl", "trans" and
   748 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   749 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   750 
   751 * Classes "order" and "linorder": 
   752 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   753 proofs changed.
   754 
   755 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   756 INCOMPATIBILITY.
   757 
   758 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   759 INCOMPATIBILITY.
   760 
   761 * Added syntactic class "size"; overloaded constant "size" now has
   762 type "'a::size ==> bool"
   763 
   764 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   765 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   766 
   767 * Added method "lexicographic_order" automatically synthesizes
   768 termination relations as lexicographic combinations of size measures
   769 -- 'function' package.
   770 
   771 * HOL/records: generalised field-update to take a function on the
   772 field rather than the new value: r(|A := x|) is translated to A_update
   773 (K x) r The K-combinator that is internally used is called K_record.
   774 INCOMPATIBILITY: Usage of the plain update functions has to be
   775 adapted.
   776  
   777 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   778 0 * x = 0, which are required for a semiring.  Richer structures do
   779 not inherit from semiring_0 anymore, because this property is a
   780 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   781 semiring_0, there is more to prove, but this is mostly trivial.
   782 
   783 * axclass "recpower" was generalized to arbitrary monoids, not just
   784 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   785 commutativity or a semiring property, add the corresponding classes.
   786 
   787 * Unified locale partial_order with class definition (cf. theory
   788 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   789 
   790 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   791 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   792 Isar level, use abbreviations instead.
   793 
   794 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   795 rarely occuring name references (e.g. ``List.op mem.simps'') require
   796 renaming (e.g. ``List.memberl.simps'').
   797 
   798 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   799 INCOMPATIBILITY.
   800 
   801 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   802 
   803 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   804 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   805 significant changes for setting up numeral syntax for types:
   806 
   807   - new constants Numeral.pred and Numeral.succ instead
   808       of former Numeral.bin_pred and Numeral.bin_succ.
   809   - Use integer operations instead of bin_add, bin_mult and so on.
   810   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   811   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   812 
   813 See HOL/Integ/IntArith.thy for an example setup.
   814 
   815 * New top level command 'normal_form' computes the normal form of a
   816 term that may contain free variables. For example ``normal_form
   817 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   818 suitable for heavy-duty computations because the functions are
   819 compiled to ML first.
   820 
   821 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   822 25 like -->); output depends on the "iff" print_mode, the default is
   823 "A = B" (with priority 50).
   824 
   825 * Renamed constants in HOL.thy and Orderings.thy:
   826     op +   ~> HOL.plus_class.plus
   827     op -   ~> HOL.minus_class.minus
   828     uminus ~> HOL.minus_class.uminus
   829     op *   ~> HOL.times_class.times
   830     op <   ~> Orderings.ord_class.less
   831     op <=  ~> Orderings.ord_class.less_eq
   832 
   833 Adaptions may be required in the following cases:
   834 
   835 a) User-defined constants using any of the names "plus", "minus", "times",
   836 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   837 may go wrong.
   838 INCOMPATIBILITY: use more specific names.
   839 
   840 b) Variables named "plus", "minus", "times", "less", "less_eq"
   841 INCOMPATIBILITY: use more specific names.
   842 
   843 c) Permutative equations (e.g. "a + b = b + a")
   844 Since the change of names also changes the order of terms, permutative
   845 rewrite rules may get applied in a different order. Experience shows that
   846 this is rarely the case (only two adaptions in the whole Isabelle
   847 distribution).
   848 INCOMPATIBILITY: rewrite proofs
   849 
   850 d) ML code directly refering to constant names
   851 This in general only affects hand-written proof tactics, simprocs and so on.
   852 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   853 of const_name ML antiquotations.
   854 
   855 * Relations less (<) and less_eq (<=) are also available on type bool.
   856 Modified syntax to disallow nesting without explicit parentheses,
   857 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   858 
   859 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   860 
   861 * Relation composition operator "op O" now has precedence 75 and binds
   862 stronger than union and intersection. INCOMPATIBILITY.
   863 
   864 * The old set interval syntax "{m..n(}" (and relatives) has been
   865 removed.  Use "{m..<n}" (and relatives) instead.
   866 
   867 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   868 "t = s" to False (by simproc "neq_simproc").  For backward
   869 compatibility this can be disabled by ML "reset use_neq_simproc".
   870 
   871 * "m dvd n" where m and n are numbers is evaluated to True/False by
   872 simp.
   873 
   874 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   875 
   876 * Theorem setsum_mult renamed to setsum_right_distrib.
   877 
   878 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   879 ``rule'' method.
   880 
   881 * Reimplemented methods ``sat'' and ``satx'', with several
   882 improvements: goals no longer need to be stated as "<prems> ==>
   883 False", equivalences (i.e. "=" on type bool) are handled, variable
   884 names of the form "lit_<n>" are no longer reserved, significant
   885 speedup.
   886 
   887 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   888 zChaff is still supported as well.
   889 
   890 * 'inductive' and 'datatype': provide projections of mutual rules,
   891 bundled as foo_bar.inducts;
   892 
   893 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   894 Library.
   895 
   896 * Library: moved theory Accessible_Part to main HOL.
   897 
   898 * Library: added theory Coinductive_List of potentially infinite lists
   899 as greatest fixed-point.
   900 
   901 * Library: added theory AssocList which implements (finite) maps as
   902 association lists.
   903 
   904 * Added proof method ``evaluation'' for efficiently solving a goal
   905 (i.e. a boolean expression) by compiling it to ML. The goal is
   906 "proved" (via an oracle) if it evaluates to True.
   907 
   908 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   909 also when invoked by the simplifier.  This results in the simplifier
   910 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   911 fast_arith_split_limit to 0 to obtain the old behavior.
   912 
   913 * Support for hex (0x20) and binary (0b1001) numerals.
   914 
   915 * New method: reify eqs (t), where eqs are equations for an
   916 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   917 parameter, computes a term s::'b and a list xs::'a list and proves the
   918 theorem I xs s = t. This is also known as reification or quoting. The
   919 resulting theorem is applied to the subgoal to substitute t with I xs
   920 s.  If t is omitted, the subgoal itself is reified.
   921 
   922 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   923 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   924 where f is supposed to be a computable function (in the sense of code
   925 generattion). The method uses reify to compute s and xs as above then
   926 applies corr_thm and uses normalization by evaluation to "prove" f s =
   927 r and finally gets the theorem t = r, which is again applied to the
   928 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   929 
   930 * Reflection: Automatic refification now handels binding, an example
   931 is available in HOL/ex/ReflectionEx.thy
   932 
   933 
   934 *** HOL-Algebra ***
   935 
   936 * Formalisation of ideals and the quotient construction over rings.
   937 
   938 * Order and lattice theory no longer based on records.
   939 INCOMPATIBILITY.
   940 
   941 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   942 greatest_closed.  INCOMPATIBILITY.
   943 
   944 * Method algebra is now set up via an attribute.  For examples see
   945 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   946 of algebraic structures.
   947 
   948 * Renamed theory CRing to Ring.
   949 
   950 
   951 *** HOL-Complex ***
   952 
   953 * Theory Real: new method ferrack implements quantifier elimination
   954 for linear arithmetic over the reals. The quantifier elimination
   955 feature is used only for decision, for compatibility with arith. This
   956 means a goal is either solved or left unchanged, no simplification.
   957 
   958 * Hyperreal: Functions root and sqrt are now defined on negative real
   959 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   960 Nonnegativity side conditions have been removed from many lemmas, so
   961 that more subgoals may now be solved by simplification; potential
   962 INCOMPATIBILITY.
   963 
   964 * Real: New axiomatic classes formalize real normed vector spaces and
   965 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   966 and norm :: 'a => real.
   967 
   968 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   969 from reals into other types. The overloaded constant Reals :: 'a set
   970 is now defined as range of_real; potential INCOMPATIBILITY.
   971 
   972 * Real: ML code generation is supported now and hence also quickcheck.
   973 Reals are implemented as arbitrary precision rationals.
   974 
   975 * Hyperreal: Several constants that previously worked only for the
   976 reals have been generalized, so they now work over arbitrary vector
   977 spaces. Type annotations may need to be added in some cases; potential
   978 INCOMPATIBILITY.
   979 
   980   Infinitesimal  :: ('a::real_normed_vector) star set
   981   HFinite        :: ('a::real_normed_vector) star set
   982   HInfinite      :: ('a::real_normed_vector) star set
   983   approx         :: ('a::real_normed_vector) star => 'a star => bool
   984   monad          :: ('a::real_normed_vector) star => 'a star set
   985   galaxy         :: ('a::real_normed_vector) star => 'a star set
   986   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   987   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   988   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   989   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   990   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   991   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   992   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   993   sgn            :: 'a::real_normed_vector => 'a
   994   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   995 
   996 * Complex: Some complex-specific constants are now abbreviations for
   997 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   998 hnorm.  Other constants have been entirely removed in favor of the
   999 polymorphic versions (INCOMPATIBILITY):
  1000 
  1001   approx        <-- capprox
  1002   HFinite       <-- CFinite
  1003   HInfinite     <-- CInfinite
  1004   Infinitesimal <-- CInfinitesimal
  1005   monad         <-- cmonad
  1006   galaxy        <-- cgalaxy
  1007   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1008   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1009   (ns)deriv     <-- (ns)cderiv
  1010 
  1011 
  1012 *** ML ***
  1013 
  1014 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1015 
  1016 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1017 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1018 init only required for impure data.  INCOMPATIBILITY: empty really
  1019 need to be empty (no dependencies on theory content!)
  1020 
  1021 * ML within Isar: antiquotations allow to embed statically-checked
  1022 formal entities in the source, referring to the context available at
  1023 compile-time.  For example:
  1024 
  1025 ML {* @{typ "'a => 'b"} *}
  1026 ML {* @{term "%x. x"} *}
  1027 ML {* @{prop "x == y"} *}
  1028 ML {* @{ctyp "'a => 'b"} *}
  1029 ML {* @{cterm "%x. x"} *}
  1030 ML {* @{cprop "x == y"} *}
  1031 ML {* @{thm asm_rl} *}
  1032 ML {* @{thms asm_rl} *}
  1033 ML {* @{const_name c} *}
  1034 ML {* @{const_syntax c} *}
  1035 ML {* @{context} *}
  1036 ML {* @{theory} *}
  1037 ML {* @{theory Pure} *}
  1038 ML {* @{simpset} *}
  1039 ML {* @{claset} *}
  1040 ML {* @{clasimpset} *}
  1041 
  1042 The same works for sources being ``used'' within an Isar context.
  1043 
  1044 * ML in Isar: improved error reporting; extra verbosity with
  1045 Toplevel.debug enabled.
  1046 
  1047 * Pure/library:
  1048 
  1049   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1050   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1051 
  1052 The semantics of "burrow" is: "take a function with *simulatanously*
  1053 transforms a list of value, and apply it *simulatanously* to a list of
  1054 list of values of the appropriate type". Compare this with "map" which
  1055 would *not* apply its argument function simulatanously but in
  1056 sequence; "fold_burrow" has an additional context.
  1057 
  1058 * Pure/library: functions map2 and fold2 with curried syntax for
  1059 simultanous mapping and folding:
  1060 
  1061     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1062     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1063 
  1064 * Pure/library: indexed lists - some functions in the Isabelle library
  1065 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1066 given more convenient names and signatures reminiscent of similar
  1067 functions for alists, tables, etc:
  1068 
  1069   val nth: 'a list -> int -> 'a 
  1070   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1071   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1072 
  1073 Note that fold_index starts counting at index 0, not 1 like foldln
  1074 used to.
  1075 
  1076 * Pure/library: added general ``divide_and_conquer'' combinator on
  1077 lists.
  1078 
  1079 * Pure/General/table.ML: the join operations now works via exceptions
  1080 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1081 admits slightly more efficient complex applications.
  1082 
  1083 * Pure: datatype Context.generic joins theory/Proof.context and
  1084 provides some facilities for code that works in either kind of
  1085 context, notably GenericDataFun for uniform theory and proof data.
  1086 
  1087 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1088 use Context.generic instead of just theory.
  1089 
  1090 * Pure: simplified internal attribute type, which is now always
  1091 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1092 vs. local (Proof.context) attributes have been discontinued, while
  1093 minimizing code duplication.  Thm.rule_attribute and
  1094 Thm.declaration_attribute build canonical attributes; see also
  1095 structure Context for further operations on Context.generic, notably
  1096 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1097 declarations and definitions.
  1098 
  1099 * Pure/kernel: consts certification ignores sort constraints given in
  1100 signature declarations.  (This information is not relevant to the
  1101 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1102 potential INCOMPATIBILITY.
  1103 
  1104 * Pure: axiomatic type classes are now purely definitional, with
  1105 explicit proofs of class axioms and super class relations performed
  1106 internally.  See Pure/axclass.ML for the main internal interfaces --
  1107 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1108 AxClass.axiomatize_class/classrel/arity supercede
  1109 Sign.add_classes/classrel/arities.
  1110 
  1111 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1112 global/local versions on theory vs. Proof.context have been
  1113 discontinued; Attrib.syntax and Method.syntax have been adapted
  1114 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1115 attributes, methods, etc.
  1116 
  1117 * Pure: several functions of signature "... -> theory -> theory * ..."
  1118 have been reoriented to "... -> theory -> ... * theory" in order to
  1119 allow natural usage in combination with the ||>, ||>>, |-> and
  1120 fold_map combinators.
  1121 
  1122 * Pure: official theorem names (closed derivations) and additional
  1123 comments (tags) are now strictly separate.  Name hints -- which are
  1124 maintained as tags -- may be attached any time without affecting the
  1125 derivation.
  1126 
  1127 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1128 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1129 achieve the old behaviour.
  1130 
  1131 * Pure: the "Goal" constant is now called "prop", supporting a
  1132 slightly more general idea of ``protecting'' meta-level rule
  1133 statements.
  1134 
  1135 * Pure: Logic.(un)varify only works in a global context, which is now
  1136 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1137 Logic.legacy_(un)varify as temporary workaround.
  1138 
  1139 * Pure: structure Name provides scalable operations for generating
  1140 internal variable names, notably Name.variants etc.  This replaces
  1141 some popular functions from term.ML:
  1142 
  1143   Term.variant		->  Name.variant
  1144   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1145   Term.invent_names	->  Name.invent_list
  1146 
  1147 Note that low-level renaming rarely occurs in new code -- operations
  1148 from structure Variable are used instead (see below).
  1149 
  1150 * Pure: structure Variable provides fundamental operations for proper
  1151 treatment of fixed/schematic variables in a context.  For example,
  1152 Variable.import introduces fixes for schematics of given facts and
  1153 Variable.export reverses the effect (up to renaming) -- this replaces
  1154 various freeze_thaw operations.
  1155 
  1156 * Pure: structure Goal provides simple interfaces for
  1157 init/conclude/finish and tactical prove operations (replacing former
  1158 Tactic.prove).  Goal.prove is the canonical way to prove results
  1159 within a given context; Goal.prove_global is a degraded version for
  1160 theory level goals, including a global Drule.standard.  Note that
  1161 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1162 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1163 in a locale context).
  1164 
  1165 * Isar: simplified treatment of user-level errors, using exception
  1166 ERROR of string uniformly.  Function error now merely raises ERROR,
  1167 without any side effect on output channels.  The Isar toplevel takes
  1168 care of proper display of ERROR exceptions.  ML code may use plain
  1169 handle/can/try; cat_error may be used to concatenate errors like this:
  1170 
  1171   ... handle ERROR msg => cat_error msg "..."
  1172 
  1173 Toplevel ML code (run directly or through the Isar toplevel) may be
  1174 embedded into the Isar toplevel with exception display/debug like
  1175 this:
  1176 
  1177   Isar.toplevel (fn () => ...)
  1178 
  1179 INCOMPATIBILITY, removed special transform_error facilities, removed
  1180 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1181 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1182 -- use plain ERROR instead.
  1183 
  1184 * Isar: theory setup now has type (theory -> theory), instead of a
  1185 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1186 
  1187 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1188 subject to ProofContext.debug/verbose flags.
  1189 
  1190 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1191 theory before entering a proof state.  Transactions now always see a
  1192 quasi-functional intermediate checkpoint, both in interactive and
  1193 batch mode.
  1194 
  1195 * Simplifier: the simpset of a running simplification process now
  1196 contains a proof context (cf. Simplifier.the_context), which is the
  1197 very context that the initial simpset has been retrieved from (by
  1198 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1199 (solver, looper etc.) may depend on arbitrary proof data.
  1200 
  1201 * Simplifier.inherit_context inherits the proof context (plus the
  1202 local bounds) of the current simplification process; any simproc
  1203 etc. that calls the Simplifier recursively should do this!  Removed
  1204 former Simplifier.inherit_bounds, which is already included here --
  1205 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1206 specify an explicit context using Simplifier.context/theory_context.
  1207 
  1208 * Simplifier/Classical Reasoner: more abstract interfaces
  1209 change_simpset/claset for modifying the simpset/claset reference of a
  1210 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1211 INCOMPATIBILITY.
  1212 
  1213 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1214 "Trueprop" etc.
  1215 
  1216 
  1217 *** System ***
  1218 
  1219 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1220 locations -- now includes the Isabelle version identifier as well.
  1221 This simplifies use of multiple Isabelle installations.
  1222 
  1223 * isabelle-process: option -S (secure mode) disables some critical
  1224 operations, notably runtime compilation and evaluation of ML source
  1225 code.
  1226 
  1227 
  1228 New in Isabelle2005 (October 2005)
  1229 ----------------------------------
  1230 
  1231 *** General ***
  1232 
  1233 * Theory headers: the new header syntax for Isar theories is
  1234 
  1235   theory <name>
  1236   imports <theory1> ... <theoryN>
  1237   uses <file1> ... <fileM>
  1238   begin
  1239 
  1240 where the 'uses' part is optional.  The previous syntax
  1241 
  1242   theory <name> = <theory1> + ... + <theoryN>:
  1243 
  1244 will disappear in the next release.  Use isatool fixheaders to convert
  1245 existing theory files.  Note that there is no change in ancient
  1246 non-Isar theories now, but these will disappear soon.
  1247 
  1248 * Theory loader: parent theories can now also be referred to via
  1249 relative and absolute paths.
  1250 
  1251 * Command 'find_theorems' searches for a list of criteria instead of a
  1252 list of constants. Known criteria are: intro, elim, dest, name:string,
  1253 simp:term, and any term. Criteria can be preceded by '-' to select
  1254 theorems that do not match. Intro, elim, dest select theorems that
  1255 match the current goal, name:s selects theorems whose fully qualified
  1256 name contain s, and simp:term selects all simplification rules whose
  1257 lhs match term.  Any other term is interpreted as pattern and selects
  1258 all theorems matching the pattern. Available in ProofGeneral under
  1259 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1260 
  1261   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1262 
  1263 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1264 matching the current goal as introduction rule and not having "HOL."
  1265 in their name (i.e. not being defined in theory HOL).
  1266 
  1267 * Command 'thms_containing' has been discontinued in favour of
  1268 'find_theorems'; INCOMPATIBILITY.
  1269 
  1270 * Communication with Proof General is now 8bit clean, which means that
  1271 Unicode text in UTF-8 encoding may be used within theory texts (both
  1272 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1273 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1274 
  1275   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1276   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1277 
  1278 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1279 Classical Reasoner.  Typical big applications run around 2 times
  1280 faster.
  1281 
  1282 
  1283 *** Document preparation ***
  1284 
  1285 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1286 of raw sources.  Only those symbols that do not require additional
  1287 LaTeX packages (depending on comments in isabellesym.sty) are
  1288 displayed properly, everything else is left verbatim.  isatool display
  1289 and isatool print are used as front ends (these are subject to the
  1290 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1291 
  1292 * Command tags control specific markup of certain regions of text,
  1293 notably folding and hiding.  Predefined tags include "theory" (for
  1294 theory begin and end), "proof" for proof commands, and "ML" for
  1295 commands involving ML code; the additional tags "visible" and
  1296 "invisible" are unused by default.  Users may give explicit tag
  1297 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1298 interpretation of tags is determined by the LaTeX job during document
  1299 preparation: see option -V of isatool usedir, or options -n and -t of
  1300 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1301 \isadroptag.
  1302 
  1303 Several document versions may be produced at the same time via isatool
  1304 usedir (the generated index.html will link all of them).  Typical
  1305 specifications include ''-V document=theory,proof,ML'' to present
  1306 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1307 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1308 these parts without any formal replacement text.  The Isabelle site
  1309 default settings produce ''document'' and ''outline'' versions as
  1310 specified above.
  1311 
  1312 * Several new antiquotations:
  1313 
  1314   @{term_type term} prints a term with its type annotated;
  1315 
  1316   @{typeof term} prints the type of a term;
  1317 
  1318   @{const const} is the same as @{term const}, but checks that the
  1319   argument is a known logical constant;
  1320 
  1321   @{term_style style term} and @{thm_style style thm} print a term or
  1322   theorem applying a "style" to it
  1323 
  1324   @{ML text}
  1325 
  1326 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1327 definitions, equations, inequations etc., 'concl' printing only the
  1328 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1329 to print the specified premise.  TermStyle.add_style provides an ML
  1330 interface for introducing further styles.  See also the "LaTeX Sugar"
  1331 document practical applications.  The ML antiquotation prints
  1332 type-checked ML expressions verbatim.
  1333 
  1334 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1335 and 'text' support optional locale specification '(in loc)', which
  1336 specifies the default context for interpreting antiquotations.  For
  1337 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1338 
  1339 * Option 'locale=NAME' of antiquotations specifies an alternative
  1340 context interpreting the subsequent argument.  For example: @{thm
  1341 [locale=lattice] inf_assoc}.
  1342 
  1343 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1344 a proof context.
  1345 
  1346 * Proper output of antiquotations for theory commands involving a
  1347 proof context (such as 'locale' or 'theorem (in loc) ...').
  1348 
  1349 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1350 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1351 
  1352 * isatool usedir: new option -C (default true) controls whether option
  1353 -D should include a copy of the original document directory; -C false
  1354 prevents unwanted effects such as copying of administrative CVS data.
  1355 
  1356 
  1357 *** Pure ***
  1358 
  1359 * Considerably improved version of 'constdefs' command.  Now performs
  1360 automatic type-inference of declared constants; additional support for
  1361 local structure declarations (cf. locales and HOL records), see also
  1362 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1363 sequential dependencies of definitions within a single 'constdefs'
  1364 section; moreover, the declared name needs to be an identifier.  If
  1365 all fails, consider to fall back on 'consts' and 'defs' separately.
  1366 
  1367 * Improved indexed syntax and implicit structures.  First of all,
  1368 indexed syntax provides a notational device for subscripted
  1369 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1370 expressions.  Secondly, in a local context with structure
  1371 declarations, number indexes \<^sub>n or the empty index (default
  1372 number 1) refer to a certain fixed variable implicitly; option
  1373 show_structs controls printing of implicit structures.  Typical
  1374 applications of these concepts involve record types and locales.
  1375 
  1376 * New command 'no_syntax' removes grammar declarations (and
  1377 translations) resulting from the given syntax specification, which is
  1378 interpreted in the same manner as for the 'syntax' command.
  1379 
  1380 * 'Advanced' translation functions (parse_translation etc.) may depend
  1381 on the signature of the theory context being presently used for
  1382 parsing/printing, see also isar-ref manual.
  1383 
  1384 * Improved 'oracle' command provides a type-safe interface to turn an
  1385 ML expression of type theory -> T -> term into a primitive rule of
  1386 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1387 is already included here); see also FOL/ex/IffExample.thy;
  1388 INCOMPATIBILITY.
  1389 
  1390 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1391 before); "cI" is no longer bound, use "c.intro" instead.
  1392 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1393 axclasses vs. locales.
  1394 
  1395 * Improved internal renaming of symbolic identifiers -- attach primes
  1396 instead of base 26 numbers.
  1397 
  1398 * New flag show_question_marks controls printing of leading question
  1399 marks in schematic variable names.
  1400 
  1401 * In schematic variable names, *any* symbol following \<^isub> or
  1402 \<^isup> is now treated as part of the base name.  For example, the
  1403 following works without printing of awkward ".0" indexes:
  1404 
  1405   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1406     by simp
  1407 
  1408 * Inner syntax includes (*(*nested*) comments*).
  1409 
  1410 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1411 annotations as "(00...)".
  1412 
  1413 * Clear separation of logical types and nonterminals, where the latter
  1414 may only occur in 'syntax' specifications or type abbreviations.
  1415 Before that distinction was only partially implemented via type class
  1416 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1417 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1418 exotic syntax specifications may require further adaption
  1419 (e.g. Cube/Cube.thy).
  1420 
  1421 * Removed obsolete type class "logic", use the top sort {} instead.
  1422 Note that non-logical types should be declared as 'nonterminals'
  1423 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1424 specifications.
  1425 
  1426 * Attributes 'induct' and 'cases': type or set names may now be
  1427 locally fixed variables as well.
  1428 
  1429 * Simplifier: can now control the depth to which conditional rewriting
  1430 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1431 Limit.
  1432 
  1433 * Simplifier: simplification procedures may now take the current
  1434 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1435 interface), which is very useful for calling the Simplifier
  1436 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1437 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1438 low-level mk_simproc no longer applies Logic.varify internally, to
  1439 allow for use in a context of fixed variables.
  1440 
  1441 * thin_tac now works even if the assumption being deleted contains !!
  1442 or ==>.  More generally, erule now works even if the major premise of
  1443 the elimination rule contains !! or ==>.
  1444 
  1445 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1446 
  1447 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1448 from Pure, which contains all common declarations already.  Both
  1449 theories are defined via plain Isabelle/Isar .thy files.
  1450 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1451 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1452 use isatool fixcpure to adapt your theory and ML sources.
  1453 
  1454 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1455 selections of theorems in named facts via index ranges.
  1456 
  1457 * 'print_theorems': in theory mode, really print the difference
  1458 wrt. the last state (works for interactive theory development only),
  1459 in proof mode print all local facts (cf. 'print_facts');
  1460 
  1461 * 'hide': option '(open)' hides only base names.
  1462 
  1463 * More efficient treatment of intermediate checkpoints in interactive
  1464 theory development.
  1465 
  1466 * Code generator is now invoked via code_module (incremental code
  1467 generation) and code_library (modular code generation, ML structures
  1468 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1469 must be quoted when used as identifiers.
  1470 
  1471 * New 'value' command for reading, evaluating and printing terms using
  1472 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1473 quoted when used as identifier.
  1474 
  1475 
  1476 *** Locales ***
  1477 
  1478 * New commands for the interpretation of locale expressions in
  1479 theories (1), locales (2) and proof contexts (3).  These generate
  1480 proof obligations from the expression specification.  After the
  1481 obligations have been discharged, theorems of the expression are added
  1482 to the theory, target locale or proof context.  The synopsis of the
  1483 commands is a follows:
  1484 
  1485   (1) interpretation expr inst
  1486   (2) interpretation target < expr
  1487   (3) interpret expr inst
  1488 
  1489 Interpretation in theories and proof contexts require a parameter
  1490 instantiation of terms from the current context.  This is applied to
  1491 specifications and theorems of the interpreted expression.
  1492 Interpretation in locales only permits parameter renaming through the
  1493 locale expression.  Interpretation is smart in that interpretations
  1494 that are active already do not occur in proof obligations, neither are
  1495 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1496 inspect active interpretations of a particular locale.  For details,
  1497 see the Isar Reference manual.  Examples can be found in
  1498 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1499 
  1500 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1501 'interpret' instead.
  1502 
  1503 * New context element 'constrains' for adding type constraints to
  1504 parameters.
  1505 
  1506 * Context expressions: renaming of parameters with syntax
  1507 redeclaration.
  1508 
  1509 * Locale declaration: 'includes' disallowed.
  1510 
  1511 * Proper static binding of attribute syntax -- i.e. types / terms /
  1512 facts mentioned as arguments are always those of the locale definition
  1513 context, independently of the context of later invocations.  Moreover,
  1514 locale operations (renaming and type / term instantiation) are applied
  1515 to attribute arguments as expected.
  1516 
  1517 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1518 actual attributes; rare situations may require Attrib.attribute to
  1519 embed those attributes into Attrib.src that lack concrete syntax.
  1520 Attribute implementations need to cooperate properly with the static
  1521 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1522 Attrib.XXX_thm etc. already do the right thing without further
  1523 intervention.  Only unusual applications -- such as "where" or "of"
  1524 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1525 on the context and the facts involved -- may have to assign parsed
  1526 values to argument tokens explicitly.
  1527 
  1528 * Changed parameter management in theorem generation for long goal
  1529 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1530 theorem statement in rare situations.
  1531 
  1532 * Locale inspection command 'print_locale' omits notes elements.  Use
  1533 'print_locale!' to have them included in the output.
  1534 
  1535 
  1536 *** Provers ***
  1537 
  1538 * Provers/hypsubst.ML: improved version of the subst method, for
  1539 single-step rewriting: it now works in bound variable contexts. New is
  1540 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1541 rewrite a different subterm than the original subst method, which is
  1542 still available as 'simplesubst'.
  1543 
  1544 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1545 and quasi orders.
  1546 
  1547 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1548 reflexive-transitive closure of relations.
  1549 
  1550 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1551 limit (previously hard-coded with a value of 20) user-definable.
  1552 
  1553 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1554 is peformed already.  Object-logics merely need to finish their
  1555 initial simpset configuration as before.  INCOMPATIBILITY.
  1556 
  1557 
  1558 *** HOL ***
  1559 
  1560 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1561 
  1562   syntax (epsilon)
  1563     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1564 
  1565 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1566 and x-symbol; use option '-m epsilon' to get it actually printed.
  1567 Moreover, the mathematically important symbolic identifier \<epsilon>
  1568 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1569 
  1570 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1571 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1572 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1573 support corresponding Isar calculations.
  1574 
  1575 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1576 instead of ":".
  1577 
  1578 * theory SetInterval: changed the syntax for open intervals:
  1579 
  1580   Old       New
  1581   {..n(}    {..<n}
  1582   {)n..}    {n<..}
  1583   {m..n(}   {m..<n}
  1584   {)m..n}   {m<..n}
  1585   {)m..n(}  {m<..<n}
  1586 
  1587 The old syntax is still supported but will disappear in the next
  1588 release.  For conversion use the following Emacs search and replace
  1589 patterns (these are not perfect but work quite well):
  1590 
  1591   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1592   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1593 
  1594 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1595 equalities in commutative rings; method 'algebra' provides a generic
  1596 interface.
  1597 
  1598 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1599 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1600 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1601 be a tuple pattern.
  1602 
  1603 Some new syntax forms are available:
  1604 
  1605   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1606   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1607   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1608   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1609 
  1610 The latter form "\<Sum>x < k. e" used to be based on a separate
  1611 function "Summation", which has been discontinued.
  1612 
  1613 * theory Finite_Set: in structured induction proofs, the insert case
  1614 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1615 (insert F x)'.
  1616 
  1617 * The 'refute' command has been extended to support a much larger
  1618 fragment of HOL, including axiomatic type classes, constdefs and
  1619 typedefs, inductive datatypes and recursion.
  1620 
  1621 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1622 Requires zChaff with proof generation to be installed.  See
  1623 HOL/ex/SAT_Examples.thy for examples.
  1624 
  1625 * Datatype induction via method 'induct' now preserves the name of the
  1626 induction variable. For example, when proving P(xs::'a list) by
  1627 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1628 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1629 in unstructured proof scripts.
  1630 
  1631 * Reworked implementation of records.  Improved scalability for
  1632 records with many fields, avoiding performance problems for type
  1633 inference. Records are no longer composed of nested field types, but
  1634 of nested extension types. Therefore the record type only grows linear
  1635 in the number of extensions and not in the number of fields.  The
  1636 top-level (users) view on records is preserved.  Potential
  1637 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1638 old record representation. The type generated for a record is called
  1639 <record_name>_ext_type.
  1640 
  1641 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1642 proofs triggered by a record definition or a simproc (if
  1643 quick_and_dirty is enabled).  Definitions of large records can take
  1644 quite long.
  1645 
  1646 New simproc record_upd_simproc for simplification of multiple record
  1647 updates enabled by default.  Moreover, trivial updates are also
  1648 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1649 occasionally, since simplification is more powerful by default.
  1650 
  1651 * typedef: proper support for polymorphic sets, which contain extra
  1652 type-variables in the term.
  1653 
  1654 * Simplifier: automatically reasons about transitivity chains
  1655 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1656 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1657 old proofs break occasionally as simplification may now solve more
  1658 goals than previously.
  1659 
  1660 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1661 present.  Works for all partial orders (class "order"), in particular
  1662 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1663 just like y <= x.
  1664 
  1665 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1666 bound variable or a constant then the let is unfolded.  Otherwise
  1667 first a is simplified to b, and then f b is simplified to g. If
  1668 possible we abstract b from g arriving at "let x = b in h x",
  1669 otherwise we unfold the let and arrive at g.  The simproc can be
  1670 enabled/disabled by the reference use_let_simproc.  Potential
  1671 INCOMPATIBILITY since simplification is more powerful by default.
  1672 
  1673 * Classical reasoning: the meson method now accepts theorems as arguments.
  1674 
  1675 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1676 jobs to provide advice on the provability of subgoals.
  1677 
  1678 * Theory OrderedGroup and Ring_and_Field: various additions and
  1679 improvements to faciliate calculations involving equalities and
  1680 inequalities.
  1681 
  1682 The following theorems have been eliminated or modified
  1683 (INCOMPATIBILITY):
  1684 
  1685   abs_eq             now named abs_of_nonneg
  1686   abs_of_ge_0        now named abs_of_nonneg
  1687   abs_minus_eq       now named abs_of_nonpos
  1688   imp_abs_id         now named abs_of_nonneg
  1689   imp_abs_neg_id     now named abs_of_nonpos
  1690   mult_pos           now named mult_pos_pos
  1691   mult_pos_le        now named mult_nonneg_nonneg
  1692   mult_pos_neg_le    now named mult_nonneg_nonpos
  1693   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1694   mult_neg           now named mult_neg_neg
  1695   mult_neg_le        now named mult_nonpos_nonpos
  1696 
  1697 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1698      
  1699      zero_le_square
  1700      not_square_less_zero 
  1701 
  1702   The following lemmas have been deleted from Real/RealPow:
  1703   
  1704      realpow_zero_zero
  1705      realpow_two
  1706      realpow_less
  1707      zero_le_power
  1708      realpow_two_le
  1709      abs_realpow_two
  1710      realpow_two_abs     
  1711 
  1712 * Theory Parity: added rules for simplifying exponents.
  1713 
  1714 * Theory List:
  1715 
  1716 The following theorems have been eliminated or modified
  1717 (INCOMPATIBILITY):
  1718 
  1719   list_all_Nil       now named list_all.simps(1)
  1720   list_all_Cons      now named list_all.simps(2)
  1721   list_all_conv      now named list_all_iff
  1722   set_mem_eq         now named mem_iff
  1723 
  1724 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1725 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1726 
  1727 
  1728 *** HOL-Complex ***
  1729 
  1730 * Theory RealDef: better support for embedding natural numbers and
  1731 integers in the reals.
  1732 
  1733 The following theorems have been eliminated or modified
  1734 (INCOMPATIBILITY):
  1735 
  1736   exp_ge_add_one_self  now requires no hypotheses
  1737   real_of_int_add      reversed direction of equality (use [symmetric])
  1738   real_of_int_minus    reversed direction of equality (use [symmetric])
  1739   real_of_int_diff     reversed direction of equality (use [symmetric])
  1740   real_of_int_mult     reversed direction of equality (use [symmetric])
  1741 
  1742 * Theory RComplete: expanded support for floor and ceiling functions.
  1743 
  1744 * Theory Ln is new, with properties of the natural logarithm
  1745 
  1746 * Hyperreal: There is a new type constructor "star" for making
  1747 nonstandard types.  The old type names are now type synonyms:
  1748 
  1749   hypreal = real star
  1750   hypnat = nat star
  1751   hcomplex = complex star
  1752 
  1753 * Hyperreal: Many groups of similarly-defined constants have been
  1754 replaced by polymorphic versions (INCOMPATIBILITY):
  1755 
  1756   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1757 
  1758   starset      <-- starsetNat, starsetC
  1759   *s*          <-- *sNat*, *sc*
  1760   starset_n    <-- starsetNat_n, starsetC_n
  1761   *sn*         <-- *sNatn*, *scn*
  1762   InternalSets <-- InternalNatSets, InternalCSets
  1763 
  1764   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1765   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1766   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1767   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1768   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1769 
  1770 * Hyperreal: Many type-specific theorems have been removed in favor of
  1771 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1772 
  1773   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1774   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1775   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1776   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1777   right_minus <-- hypreal_add_minus
  1778   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1779   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1780   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1781   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1782   mult_1_right <-- hcomplex_mult_one_right
  1783   mult_zero_left <-- hcomplex_mult_zero_left
  1784   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1785   right_distrib <-- hypnat_add_mult_distrib2
  1786   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1787   right_inverse <-- hypreal_mult_inverse
  1788   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1789   order_refl <-- {hypreal,hypnat}_le_refl
  1790   order_trans <-- {hypreal,hypnat}_le_trans
  1791   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1792   order_less_le <-- {hypreal,hypnat}_less_le
  1793   linorder_linear <-- {hypreal,hypnat}_le_linear
  1794   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1795   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1796   add_nonneg_nonneg <-- hypreal_le_add_order
  1797 
  1798 * Hyperreal: Separate theorems having to do with type-specific
  1799 versions of constants have been merged into theorems that apply to the
  1800 new polymorphic constants (INCOMPATIBILITY):
  1801 
  1802   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1803   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1804   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1805   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1806   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1807   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1808   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1809   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1810   STAR_diff <-- {STAR,STARC}_diff
  1811   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1812     STARC_hcomplex_of_complex}_image_subset
  1813   starset_n_Un <-- starset{Nat,C}_n_Un
  1814   starset_n_Int <-- starset{Nat,C}_n_Int
  1815   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1816   starset_n_diff <-- starset{Nat,C}_n_diff
  1817   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1818   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1819   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1820   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1821   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1822   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1823   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1824   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1825   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1826   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1827   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1828   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1829   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1830   starfun_diff <-- starfun{C,RC,CR}_diff
  1831   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1832   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1833   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1834   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1835   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1836   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1837   starfun_Id <-- starfunC_Id
  1838   starfun_approx <-- starfun{Nat,CR}_approx
  1839   starfun_capprox <-- starfun{C,RC}_capprox
  1840   starfun_abs <-- starfunNat_rabs
  1841   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1842   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1843   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1844   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1845   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1846   starfun_add_approx <-- starfunCR_add_approx
  1847   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1848   starfun_divide <-- starfun{C,CR,RC}_divide
  1849   starfun_n <-- starfun{Nat,C}_n
  1850   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1851   starfun_n_add <-- starfun{Nat,C}_n_add
  1852   starfun_n_add_minus <-- starfunNat_n_add_minus
  1853   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1854   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1855   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1856 
  1857   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1858   star_n_minus <-- {hypreal,hcomplex}_minus
  1859   star_n_diff <-- {hypreal,hcomplex}_diff
  1860   star_n_mult <-- {hypreal,hcomplex}_mult
  1861   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1862   star_n_le <-- {hypreal,hypnat}_le
  1863   star_n_less <-- {hypreal,hypnat}_less
  1864   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1865   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1866   star_n_abs <-- hypreal_hrabs
  1867   star_n_divide <-- hcomplex_divide
  1868 
  1869   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1870   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1871   star_of_diff <-- hypreal_of_real_diff
  1872   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1873   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1874   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1875   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1876   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1877   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1878   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1879   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1880   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1881   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1882   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1883   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1884   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1885   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1886   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1887   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1888   star_of_power <-- hypreal_of_real_power
  1889   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1890 
  1891 * Hyperreal: new method "transfer" that implements the transfer
  1892 principle of nonstandard analysis. With a subgoal that mentions
  1893 nonstandard types like "'a star", the command "apply transfer"
  1894 replaces it with an equivalent one that mentions only standard types.
  1895 To be successful, all free variables must have standard types; non-
  1896 standard variables must have explicit universal quantifiers.
  1897 
  1898 * Hyperreal: A theory of Taylor series.
  1899 
  1900 
  1901 *** HOLCF ***
  1902 
  1903 * Discontinued special version of 'constdefs' (which used to support
  1904 continuous functions) in favor of the general Pure one with full
  1905 type-inference.
  1906 
  1907 * New simplification procedure for solving continuity conditions; it
  1908 is much faster on terms with many nested lambda abstractions (cubic
  1909 instead of exponential time).
  1910 
  1911 * New syntax for domain package: selector names are now optional.
  1912 Parentheses should be omitted unless argument is lazy, for example:
  1913 
  1914   domain 'a stream = cons "'a" (lazy "'a stream")
  1915 
  1916 * New command 'fixrec' for defining recursive functions with pattern
  1917 matching; defining multiple functions with mutual recursion is also
  1918 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1919 sinr, or any data constructor defined by the domain package. The given
  1920 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1921 syntax and examples.
  1922 
  1923 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1924 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1925 but the proof obligation additionally includes an admissibility
  1926 requirement. The packages generate instances of class cpo or pcpo,
  1927 with continuity and strictness theorems for Rep and Abs.
  1928 
  1929 * HOLCF: Many theorems have been renamed according to a more standard naming
  1930 scheme (INCOMPATIBILITY):
  1931 
  1932   foo_inject:  "foo$x = foo$y ==> x = y"
  1933   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1934   foo_less:    "(foo$x << foo$y) = (x << y)"
  1935   foo_strict:  "foo$UU = UU"
  1936   foo_defined: "... ==> foo$x ~= UU"
  1937   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1938 
  1939 
  1940 *** ZF ***
  1941 
  1942 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1943 including the First Isomorphism Theorem (on quotienting by the kernel
  1944 of a homomorphism).
  1945 
  1946 * ZF/Simplifier: install second copy of type solver that actually
  1947 makes use of TC rules declared to Isar proof contexts (or locales);
  1948 the old version is still required for ML proof scripts.
  1949 
  1950 
  1951 *** Cube ***
  1952 
  1953 * Converted to Isar theory format; use locales instead of axiomatic
  1954 theories.
  1955 
  1956 
  1957 *** ML ***
  1958 
  1959 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1960 for ||>, ||>>, |>>,
  1961 
  1962 * Pure/library.ML no longer defines its own option datatype, but uses
  1963 that of the SML basis, which has constructors NONE and SOME instead of
  1964 None and Some, as well as exception Option.Option instead of OPTION.
  1965 The functions the, if_none, is_some, is_none have been adapted
  1966 accordingly, while Option.map replaces apsome.
  1967 
  1968 * Pure/library.ML: the exception LIST has been given up in favour of
  1969 the standard exceptions Empty and Subscript, as well as
  1970 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1971 superceded by the standard hd and tl functions etc.
  1972 
  1973 A number of basic list functions are no longer exported to the ML
  1974 toplevel, as they are variants of predefined functions.  The following
  1975 suggests how one can translate existing code:
  1976 
  1977     rev_append xs ys = List.revAppend (xs, ys)
  1978     nth_elem (i, xs) = List.nth (xs, i)
  1979     last_elem xs = List.last xs
  1980     flat xss = List.concat xss
  1981     seq fs = List.app fs
  1982     partition P xs = List.partition P xs
  1983     mapfilter f xs = List.mapPartial f xs
  1984 
  1985 * Pure/library.ML: several combinators for linear functional
  1986 transformations, notably reverse application and composition:
  1987 
  1988   x |> f                f #> g
  1989   (x, y) |-> f          f #-> g
  1990 
  1991 * Pure/library.ML: introduced/changed precedence of infix operators:
  1992 
  1993   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1994   infix 2 ?;
  1995   infix 3 o oo ooo oooo;
  1996   infix 4 ~~ upto downto;
  1997 
  1998 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1999 infix operators.
  2000 
  2001 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2002 fold_map support linear functional transformations and nesting.  For
  2003 example:
  2004 
  2005   fold f [x1, ..., xN] y =
  2006     y |> f x1 |> ... |> f xN
  2007 
  2008   (fold o fold) f [xs1, ..., xsN] y =
  2009     y |> fold f xs1 |> ... |> fold f xsN
  2010 
  2011   fold f [x1, ..., xN] =
  2012     f x1 #> ... #> f xN
  2013 
  2014   (fold o fold) f [xs1, ..., xsN] =
  2015     fold f xs1 #> ... #> fold f xsN
  2016 
  2017 * Pure/library.ML: the following selectors on type 'a option are
  2018 available:
  2019 
  2020   the:               'a option -> 'a  (*partial*)
  2021   these:             'a option -> 'a  where 'a = 'b list
  2022   the_default: 'a -> 'a option -> 'a
  2023   the_list:          'a option -> 'a list
  2024 
  2025 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2026 basic operations for association lists, following natural argument
  2027 order; moreover the explicit equality predicate passed here avoids
  2028 potentially expensive polymorphic runtime equality checks.
  2029 The old functions may be expressed as follows:
  2030 
  2031   assoc = uncurry (AList.lookup (op =))
  2032   assocs = these oo AList.lookup (op =)
  2033   overwrite = uncurry (AList.update (op =)) o swap
  2034 
  2035 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2036 
  2037   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2038   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2039 
  2040 replacing make_keylist and keyfilter (occassionally used)
  2041 Naive rewrites:
  2042 
  2043   make_keylist = AList.make
  2044   keyfilter = AList.find (op =)
  2045 
  2046 * eq_fst and eq_snd now take explicit equality parameter, thus
  2047   avoiding eqtypes. Naive rewrites:
  2048 
  2049     eq_fst = eq_fst (op =)
  2050     eq_snd = eq_snd (op =)
  2051 
  2052 * Removed deprecated apl and apr (rarely used).
  2053   Naive rewrites:
  2054 
  2055     apl (n, op) =>>= curry op n
  2056     apr (op, m) =>>= fn n => op (n, m)
  2057 
  2058 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2059 provides a reasonably efficient light-weight implementation of sets as
  2060 lists.
  2061 
  2062 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2063 few new operations; existing lookup and update are now curried to
  2064 follow natural argument order (for use with fold etc.);
  2065 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2066 
  2067 * Pure/General: output via the Isabelle channels of
  2068 writeln/warning/error etc. is now passed through Output.output, with a
  2069 hook for arbitrary transformations depending on the print_mode
  2070 (cf. Output.add_mode -- the first active mode that provides a output
  2071 function wins).  Already formatted output may be embedded into further
  2072 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2073 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2074 accommodate easy composition of diagnostic messages etc.  Programmers
  2075 rarely need to care about Output.output or Output.raw at all, with
  2076 some notable exceptions: Output.output is required when bypassing the
  2077 standard channels (writeln etc.), or in token translations to produce
  2078 properly formatted results; Output.raw is required when capturing
  2079 already output material that will eventually be presented to the user
  2080 a second time.  For the default print mode, both Output.output and
  2081 Output.raw have no effect.
  2082 
  2083 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2084 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2085 cumulative results are displayed at the end of a batch session.
  2086 
  2087 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2088 replaced by File.platform_path and File.shell_path (with appropriate
  2089 hooks).  This provides a clean interface for unusual systems where the
  2090 internal and external process view of file names are different.
  2091 
  2092 * Pure: more efficient orders for basic syntactic entities: added
  2093 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2094 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2095 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2096 orders now -- potential INCOMPATIBILITY for code that depends on a
  2097 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2098 Library.sort_strings on result).
  2099 
  2100 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2101 fold_types traverse types/terms from left to right, observing natural
  2102 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2103 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2104 
  2105 * Pure: name spaces have been refined, with significant changes of the
  2106 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2107 to extern(_table).  The plain name entry path is superceded by a
  2108 general 'naming' context, which also includes the 'policy' to produce
  2109 a fully qualified name and external accesses of a fully qualified
  2110 name; NameSpace.extend is superceded by context dependent
  2111 Sign.declare_name.  Several theory and proof context operations modify
  2112 the naming context.  Especially note Theory.restore_naming and
  2113 ProofContext.restore_naming to get back to a sane state; note that
  2114 Theory.add_path is no longer sufficient to recover from
  2115 Theory.absolute_path in particular.
  2116 
  2117 * Pure: new flags short_names (default false) and unique_names
  2118 (default true) for controlling output of qualified names.  If
  2119 short_names is set, names are printed unqualified.  If unique_names is
  2120 reset, the name prefix is reduced to the minimum required to achieve
  2121 the original result when interning again, even if there is an overlap
  2122 with earlier declarations.
  2123 
  2124 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2125 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2126 (useful for printing error messages).  INCOMPATIBILITY.
  2127 
  2128 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2129 Theory.theory are now identified, referring to the universal
  2130 Context.theory (see Pure/context.ML).  Actual signature and theory
  2131 content is managed as theory data.  The old code and interfaces were
  2132 spread over many files and structures; the new arrangement introduces
  2133 considerable INCOMPATIBILITY to gain more clarity:
  2134 
  2135   Context -- theory management operations (name, identity, inclusion,
  2136     parents, ancestors, merge, etc.), plus generic theory data;
  2137 
  2138   Sign -- logical signature and syntax operations (declaring consts,
  2139     types, etc.), plus certify/read for common entities;
  2140 
  2141   Theory -- logical theory operations (stating axioms, definitions,
  2142     oracles), plus a copy of logical signature operations (consts,
  2143     types, etc.); also a few basic management operations (Theory.copy,
  2144     Theory.merge, etc.)
  2145 
  2146 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2147 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2148 for convenience -- they merely return the theory.
  2149 
  2150 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2151 
  2152 * Pure: the Isar proof context type is already defined early in Pure
  2153 as Context.proof (note that ProofContext.context and Proof.context are
  2154 aliases, where the latter is the preferred name).  This enables other
  2155 Isabelle components to refer to that type even before Isar is present.
  2156 
  2157 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2158 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2159 any of these kinds.  For example, Sign.intern typeK is now
  2160 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2161 Theory.hide_types.  Also note that former
  2162 Theory.hide_classes/types/consts are now
  2163 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2164 internalize their arguments!  INCOMPATIBILITY.
  2165 
  2166 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2167 datatype thmref (with constructors Name and NameSelection) instead of
  2168 plain string -- INCOMPATIBILITY;
  2169 
  2170 * Pure: cases produced by proof methods specify options, where NONE
  2171 means to remove case bindings -- INCOMPATIBILITY in
  2172 (RAW_)METHOD_CASES.
  2173 
  2174 * Pure: the following operations retrieve axioms or theorems from a
  2175 theory node or theory hierarchy, respectively:
  2176 
  2177   Theory.axioms_of: theory -> (string * term) list
  2178   Theory.all_axioms_of: theory -> (string * term) list
  2179   PureThy.thms_of: theory -> (string * thm) list
  2180   PureThy.all_thms_of: theory -> (string * thm) list
  2181 
  2182 * Pure: print_tac now outputs the goal through the trace channel.
  2183 
  2184 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2185 Reference Toplevel.debug (default false) controls detailed printing
  2186 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2187 controls execution profiling -- set to 1 for time and 2 for space
  2188 (both increase the runtime).
  2189 
  2190 * Isar session: The initial use of ROOT.ML is now always timed,
  2191 i.e. the log will show the actual process times, in contrast to the
  2192 elapsed wall-clock time that the outer shell wrapper produces.
  2193 
  2194 * Simplifier: improved handling of bound variables (nameless
  2195 representation, avoid allocating new strings).  Simprocs that invoke
  2196 the Simplifier recursively should use Simplifier.inherit_bounds to
  2197 avoid local name clashes.  Failure to do so produces warnings
  2198 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2199 for further details.
  2200 
  2201 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2202 bindings for all theorems stored within a given theory; this may help
  2203 in porting non-Isar theories to Isar ones, while keeping ML proof
  2204 scripts for the time being.
  2205 
  2206 * ML operator HTML.with_charset specifies the charset begin used for
  2207 generated HTML files.  For example:
  2208 
  2209   HTML.with_charset "utf-8" use_thy "Hebrew";
  2210   HTML.with_charset "utf-8" use_thy "Chinese";
  2211 
  2212 
  2213 *** System ***
  2214 
  2215 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2216 isabelle, isatool etc.).
  2217 
  2218 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2219 isatool doc, isatool mkdir, display_drafts etc.).
  2220 
  2221 * isatool usedir: option -f allows specification of the ML file to be
  2222 used by Isabelle; default is ROOT.ML.
  2223 
  2224 * New isatool version outputs the version identifier of the Isabelle
  2225 distribution being used.
  2226 
  2227 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2228 (containing Boolean satisfiability problems) into Isabelle/HOL
  2229 theories.
  2230 
  2231 
  2232 
  2233 New in Isabelle2004 (April 2004)
  2234 --------------------------------
  2235 
  2236 *** General ***
  2237 
  2238 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2239   Replaces linorder.ML.
  2240 
  2241 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2242   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2243   (\<a>...\<z>), are now considered normal letters, and can therefore
  2244   be used anywhere where an ASCII letter (a...zA...Z) has until
  2245   now. COMPATIBILITY: This obviously changes the parsing of some
  2246   terms, especially where a symbol has been used as a binder, say
  2247   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2248   as an identifier.  Fix it by inserting a space around former
  2249   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2250   existing theory and ML files.
  2251 
  2252 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2253 
  2254 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2255   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2256   a normal (but invisible) letter. For multiple letter subscripts repeat
  2257   \<^isub> like this: x\<^isub>1\<^isub>2.
  2258 
  2259 * Pure: There are now sub-/superscripts that can span more than one
  2260   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2261   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2262   superscript. The new control characters are not identifier parts.
  2263 
  2264 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2265   content of "..." to the latex file instead of \isacntrl... . The "..."
  2266   may consist of any printable characters excluding the end bracket >.
  2267 
  2268 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2269   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2270   declare constants "final", which prevents their being given a definition
  2271   later.  It is useful for constants whose behaviour is fixed axiomatically
  2272   rather than definitionally, such as the meta-logic connectives.
  2273 
  2274 * Pure: 'instance' now handles general arities with general sorts
  2275   (i.e. intersections of classes),
  2276 
  2277 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2278   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2279   It can be changed to alter the colors/layout of generated pages.
  2280 
  2281 
  2282 *** Isar ***
  2283 
  2284 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2285   cut_tac, subgoal_tac and thin_tac:
  2286   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2287     locales are no longer forced to write Isar proof scripts.
  2288     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2289     emulations.
  2290   - INCOMPATIBILITY: names of variables to be instantiated may no
  2291     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2292     This is consistent with the instantiation attribute "where".
  2293 
  2294 * Attributes "where" and "of":
  2295   - Now take type variables of instantiated theorem into account when reading
  2296     the instantiation string.  This fixes a bug that caused instantiated
  2297     theorems to have too special types in some circumstances.
  2298   - "where" permits explicit instantiations of type variables.
  2299 
  2300 * Calculation commands "moreover" and "also" no longer interfere with
  2301   current facts ("this"), admitting arbitrary combinations with "then"
  2302   and derived forms.
  2303 
  2304 * Locales:
  2305   - Goal statements involving the context element "includes" no longer
  2306     generate theorems with internal delta predicates (those ending on
  2307     "_axioms") in the premise.
  2308     Resolve particular premise with <locale>.intro to obtain old form.
  2309   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2310     specification and "includes" elements in goal statement.
  2311   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2312     [intro?] and [elim?] (respectively) by default.
  2313   - Experimental command for instantiation of locales in proof contexts:
  2314         instantiate <label>[<attrs>]: <loc>
  2315     Instantiates locale <loc> and adds all its theorems to the current context
  2316     taking into account their attributes.  Label and attrs are optional
  2317     modifiers, like in theorem declarations.  If present, names of
  2318     instantiated theorems are qualified with <label>, and the attributes
  2319     <attrs> are applied after any attributes these theorems might have already.
  2320       If the locale has assumptions, a chained fact of the form
  2321     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2322     are derived.  The command does not support old-style locales declared
  2323     with "locale (open)".
  2324       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2325 
  2326 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2327   (Isar) contexts.
  2328 
  2329 
  2330 *** HOL ***
  2331 
  2332 * Proof import: new image HOL4 contains the imported library from
  2333   the HOL4 system with about 2500 theorems. It is imported by
  2334   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2335   can be used like any other Isabelle image.  See
  2336   HOL/Import/HOL/README for more information.
  2337 
  2338 * Simplifier:
  2339   - Much improved handling of linear and partial orders.
  2340     Reasoners for linear and partial orders are set up for type classes
  2341     "linorder" and "order" respectively, and are added to the default simpset
  2342     as solvers.  This means that the simplifier can build transitivity chains
  2343     to solve goals from the assumptions.
  2344   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2345     of blast or auto after simplification become unnecessary because the goal
  2346     is solved by simplification already.
  2347 
  2348 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2349     all proved in axiomatic type classes for semirings, rings and fields.
  2350 
  2351 * Numerics:
  2352   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2353     now formalized using the Ring_and_Field theory mentioned above.
  2354   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2355     than before, because now they are set up once in a generic manner.
  2356   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2357     Look for the general versions in Ring_and_Field (and Power if they concern
  2358     exponentiation).
  2359 
  2360 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2361 
  2362 * Records:
  2363   - Record types are now by default printed with their type abbreviation
  2364     instead of the list of all field types. This can be configured via
  2365     the reference "print_record_type_abbr".
  2366   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2367     (not enabled by default).
  2368   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2369     EX x. x = sel r to True (not enabled by default).
  2370   - Tactic "record_split_simp_tac" to split and simplify records added.
  2371 
  2372 * 'specification' command added, allowing for definition by
  2373   specification.  There is also an 'ax_specification' command that
  2374   introduces the new constants axiomatically.
  2375 
  2376 * arith(_tac) is now able to generate counterexamples for reals as well.
  2377 
  2378 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2379 
  2380 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2381   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2382 
  2383 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2384   matrix theory to linear programming.
  2385 
  2386 * Unions and Intersections:
  2387   The latex output syntax of UN and INT has been changed
  2388   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2389   i.e. the index formulae has become a subscript.
  2390   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2391 
  2392 * Unions and Intersections over Intervals:
  2393   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2394   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2395   like in normal math, and corresponding versions for < and for intersection.
  2396 
  2397 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2398   lexicographic dictonary ordering has been added as "lexord".
  2399 
  2400 * ML: the legacy theory structures Int and List have been removed. They had
  2401   conflicted with ML Basis Library structures having the same names.
  2402 
  2403 * 'refute' command added to search for (finite) countermodels.  Only works
  2404   for a fragment of HOL.  The installation of an external SAT solver is
  2405   highly recommended.  See "HOL/Refute.thy" for details.
  2406 
  2407 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2408   formulae under an assignment of free variables to random values.
  2409   In contrast to 'refute', it can deal with inductive datatypes,
  2410   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2411   for examples.
  2412 
  2413 
  2414 *** HOLCF ***
  2415 
  2416 * Streams now come with concatenation and are part of the HOLCF image
  2417 
  2418 
  2419 
  2420 New in Isabelle2003 (May 2003)
  2421 ------------------------------
  2422 
  2423 *** General ***
  2424 
  2425 * Provers/simplifier:
  2426 
  2427   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2428     Assumptions are now subject to complete mutual simplification,
  2429     not just from left to right. The simplifier now preserves
  2430     the order of assumptions.
  2431 
  2432     Potential INCOMPATIBILITY:
  2433 
  2434     -- simp sometimes diverges where the old version did
  2435        not, e.g. invoking simp on the goal
  2436 
  2437         [| P (f x); y = x; f x = f y |] ==> Q
  2438 
  2439        now gives rise to the infinite reduction sequence
  2440 
  2441         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2442 
  2443        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2444        kind of problem.
  2445 
  2446     -- Tactics combining classical reasoner and simplification (such as auto)
  2447        are also affected by this change, because many of them rely on
  2448        simp. They may sometimes diverge as well or yield a different numbers
  2449        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2450        in case of problems. Sometimes subsequent calls to the classical
  2451        reasoner will fail because a preceeding call to the simplifier too
  2452        eagerly simplified the goal, e.g. deleted redundant premises.
  2453 
  2454   - The simplifier trace now shows the names of the applied rewrite rules
  2455 
  2456   - You can limit the number of recursive invocations of the simplifier
  2457     during conditional rewriting (where the simplifie tries to solve the
  2458     conditions before applying the rewrite rule):
  2459     ML "simp_depth_limit := n"
  2460     where n is an integer. Thus you can force termination where previously
  2461     the simplifier would diverge.
  2462 
  2463   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2464 
  2465   - No longer aborts on failed congruence proof.  Instead, the
  2466     congruence is ignored.
  2467 
  2468 * Pure: New generic framework for extracting programs from constructive
  2469   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2470   as HOL/Extraction for some case studies.
  2471 
  2472 * Pure: The main goal of the proof state is no longer shown by default, only
  2473 the subgoals. This behaviour is controlled by a new flag.
  2474    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2475 (ML: Proof.show_main_goal).
  2476 
  2477 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2478 rules whose conclusion matches subgoal 1:
  2479       PG menu: Isabelle/Isar -> Show me -> matching rules
  2480 The rules are ordered by how closely they match the subgoal.
  2481 In particular, rules that solve a subgoal outright are displayed first
  2482 (or rather last, the way they are printed).
  2483 (ML: ProofGeneral.print_intros())
  2484 
  2485 * Pure: New flag trace_unify_fail causes unification to print
  2486 diagnostic information (PG: in trace buffer) when it fails. This is
  2487 useful for figuring out why single step proofs like rule, erule or
  2488 assumption failed.
  2489 
  2490 * Pure: Locale specifications now produce predicate definitions
  2491 according to the body of text (covering assumptions modulo local
  2492 definitions); predicate "loc_axioms" covers newly introduced text,
  2493 while "loc" is cumulative wrt. all included locale expressions; the
  2494 latter view is presented only on export into the global theory
  2495 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2496 on the old view without predicates;
  2497 
  2498 * Pure: predefined locales "var" and "struct" are useful for sharing
  2499 parameters (as in CASL, for example); just specify something like
  2500 ``var x + var y + struct M'' as import;
  2501 
  2502 * Pure: improved thms_containing: proper indexing of facts instead of
  2503 raw theorems; check validity of results wrt. current name space;
  2504 include local facts of proof configuration (also covers active
  2505 locales), cover fixed variables in index; may use "_" in term
  2506 specification; an optional limit for the number of printed facts may
  2507 be given (the default is 40);
  2508 
  2509 * Pure: disallow duplicate fact bindings within new-style theory files
  2510 (batch-mode only);
  2511 
  2512 * Provers: improved induct method: assumptions introduced by case
  2513 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2514 the goal statement); "foo" still refers to all facts collectively;
  2515 
  2516 * Provers: the function blast.overloaded has been removed: all constants
  2517 are regarded as potentially overloaded, which improves robustness in exchange
  2518 for slight decrease in efficiency;
  2519 
  2520 * Provers/linorder: New generic prover for transitivity reasoning over
  2521 linear orders.  Note: this prover is not efficient!
  2522 
  2523 * Isar: preview of problems to finish 'show' now produce an error
  2524 rather than just a warning (in interactive mode);
  2525 
  2526 
  2527 *** HOL ***
  2528 
  2529 * arith(_tac)
  2530 
  2531  - Produces a counter example if it cannot prove a goal.
  2532    Note that the counter example may be spurious if the goal is not a formula
  2533    of quantifier-free linear arithmetic.
  2534    In ProofGeneral the counter example appears in the trace buffer.
  2535 
  2536  - Knows about div k and mod k where k is a numeral of type nat or int.
  2537 
  2538  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2539    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2540    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2541 
  2542 * simp's arithmetic capabilities have been enhanced a bit: it now
  2543 takes ~= in premises into account (by performing a case split);
  2544 
  2545 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2546 are distributed over a sum of terms;
  2547 
  2548 * New tactic "trans_tac" and method "trans" instantiate
  2549 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2550 "<=", "<" and "=").
  2551 
  2552 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2553 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2554 
  2555 * 'typedef' command has new option "open" to suppress the set
  2556 definition;
  2557 
  2558 * functions Min and Max on finite sets have been introduced (theory
  2559 Finite_Set);
  2560 
  2561 * attribute [symmetric] now works for relations as well; it turns
  2562 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2563 
  2564 * induct over a !!-quantified statement (say !!x1..xn):
  2565   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2566 
  2567 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2568 %x. None. Warning: empty_def now refers to the previously hidden definition
  2569 of the empty set.
  2570 
  2571 * Algebra: formalization of classical algebra.  Intended as base for
  2572 any algebraic development in Isabelle.  Currently covers group theory
  2573 (up to Sylow's theorem) and ring theory (Universal Property of
  2574 Univariate Polynomials).  Contributions welcome;
  2575 
  2576 * GroupTheory: deleted, since its material has been moved to Algebra;
  2577 
  2578 * Complex: new directory of the complex numbers with numeric constants,
  2579 nonstandard complex numbers, and some complex analysis, standard and
  2580 nonstandard (Jacques Fleuriot);
  2581 
  2582 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2583 
  2584 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2585 Fleuriot);
  2586 
  2587 * Real/HahnBanach: updated and adapted to locales;
  2588 
  2589 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2590 Gray and Kramer);
  2591 
  2592 * UNITY: added the Meier-Sanders theory of progress sets;
  2593 
  2594 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2595 as abstract algorithms, instantiated to the JVM;
  2596 
  2597 * Bali: Java source language formalization. Type system, operational
  2598 semantics, axiomatic semantics. Supported language features:
  2599 classes, interfaces, objects,virtual methods, static methods,
  2600 static/instance fields, arrays, access modifiers, definite
  2601 assignment, exceptions.
  2602 
  2603 
  2604 *** ZF ***
  2605 
  2606 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2607 universe, etc.);
  2608 
  2609 * Main ZF: virtually all theories converted to new-style format;
  2610 
  2611 
  2612 *** ML ***
  2613 
  2614 * Pure: Tactic.prove provides sane interface for internal proofs;
  2615 omits the infamous "standard" operation, so this is more appropriate
  2616 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2617 
  2618 * Pure: improved error reporting of simprocs;
  2619 
  2620 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2621 up simprocs;
  2622 
  2623 
  2624 *** Document preparation ***
  2625 
  2626 * uses \par instead of \\ for line breaks in theory text. This may
  2627 shift some page breaks in large documents. To get the old behaviour
  2628 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2629 
  2630 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2631 other packages
  2632 
  2633 * \<euro> now needs package babel/greek instead of marvosym (which
  2634 broke \Rightarrow)
  2635 
  2636 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2637 textcomp package)
  2638 
  2639 
  2640 
  2641 New in Isabelle2002 (March 2002)
  2642 --------------------------------
  2643 
  2644 *** Document preparation ***
  2645 
  2646 * greatly simplified document preparation setup, including more
  2647 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2648 instructive isatool mkdir; users should basically be able to get
  2649 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2650 users may run a separate document processing stage manually like this:
  2651 "isatool usedir -D output HOL Test && isatool document Test/output";
  2652 
  2653 * theory dependency graph may now be incorporated into documents;
  2654 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2655 with \includegraphics of LaTeX;
  2656 
  2657 * proper spacing of consecutive markup elements, especially text
  2658 blocks after section headings;
  2659 
  2660 * support bold style (for single symbols only), input syntax is like
  2661 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2662 
  2663 * \<bullet> is now output as bold \cdot by default, which looks much
  2664 better in printed text;
  2665 
  2666 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2667 note that these symbols are currently unavailable in Proof General /
  2668 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2669 
  2670 * isatool latex no longer depends on changed TEXINPUTS, instead
  2671 isatool document copies the Isabelle style files to the target
  2672 location;
  2673 
  2674 
  2675 *** Isar ***
  2676 
  2677 * Pure/Provers: improved proof by cases and induction;
  2678   - 'case' command admits impromptu naming of parameters (such as
  2679     "case (Suc n)");
  2680   - 'induct' method divinates rule instantiation from the inductive
  2681     claim; no longer requires excessive ?P bindings for proper
  2682     instantiation of cases;
  2683   - 'induct' method properly enumerates all possibilities of set/type
  2684     rules; as a consequence facts may be also passed through *type*
  2685     rules without further ado;
  2686   - 'induct' method now derives symbolic cases from the *rulified*
  2687     rule (before it used to rulify cases stemming from the internal
  2688     atomized version); this means that the context of a non-atomic
  2689     statement becomes is included in the hypothesis, avoiding the
  2690     slightly cumbersome show "PROP ?case" form;
  2691   - 'induct' may now use elim-style induction rules without chaining
  2692     facts, using ``missing'' premises from the goal state; this allows
  2693     rules stemming from inductive sets to be applied in unstructured
  2694     scripts, while still benefitting from proper handling of non-atomic
  2695     statements; NB: major inductive premises need to be put first, all
  2696     the rest of the goal is passed through the induction;
  2697   - 'induct' proper support for mutual induction involving non-atomic
  2698     rule statements (uses the new concept of simultaneous goals, see
  2699     below);
  2700   - append all possible rule selections, but only use the first
  2701     success (no backtracking);
  2702   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2703   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2704   - added 'print_induct_rules' (covered by help item in recent Proof
  2705     General versions);
  2706   - moved induct/cases attributes to Pure, methods to Provers;
  2707   - generic method setup instantiated for FOL and HOL;
  2708 
  2709 * Pure: support multiple simultaneous goal statements, for example
  2710 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2711 meta-level mechanism, this acts as if several individual goals had
  2712 been stated separately; in particular common proof methods need to be
  2713 repeated in order to cover all claims; note that a single elimination
  2714 step is *not* sufficient to establish the two conjunctions, so this
  2715 fails:
  2716 
  2717   assume "A & B" then have A and B ..   (*".." fails*)
  2718 
  2719 better use "obtain" in situations as above; alternative refer to
  2720 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2721 
  2722 * Pure: proper integration with ``locales''; unlike the original
  2723 version by Florian Kammller, Isar locales package high-level proof
  2724 contexts rather than raw logical ones (e.g. we admit to include
  2725 attributes everywhere); operations on locales include merge and
  2726 rename; support for implicit arguments (``structures''); simultaneous
  2727 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2728 some examples;
  2729 
  2730 * Pure: the following commands have been ``localized'', supporting a
  2731 target locale specification "(in name)": 'lemma', 'theorem',
  2732 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2733 stored both within the locale and at the theory level (exported and
  2734 qualified by the locale name);
  2735 
  2736 * Pure: theory goals may now be specified in ``long'' form, with
  2737 ad-hoc contexts consisting of arbitrary locale elements. for example
  2738 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2739 definitions may be given, too); the result is a meta-level rule with
  2740 the context elements being discharged in the obvious way;
  2741 
  2742 * Pure: new proof command 'using' allows to augment currently used
  2743 facts after a goal statement ('using' is syntactically analogous to
  2744 'apply', but acts on the goal's facts only); this allows chained facts
  2745 to be separated into parts given before and after a claim, as in
  2746 ``from a and b have C using d and e <proof>'';
  2747 
  2748 * Pure: renamed "antecedent" case to "rule_context";
  2749 
  2750 * Pure: new 'judgment' command records explicit information about the
  2751 object-logic embedding (used by several tools internally); no longer
  2752 use hard-wired "Trueprop";
  2753 
  2754 * Pure: added 'corollary' command;
  2755 
  2756 * Pure: fixed 'token_translation' command;
  2757 
  2758 * Pure: removed obsolete 'exported' attribute;
  2759 
  2760 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2761 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2762 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2763 
  2764 * Pure: method 'atomize' presents local goal premises as object-level
  2765 statements (atomic meta-level propositions); setup controlled via
  2766 rewrite rules declarations of 'atomize' attribute; example
  2767 application: 'induct' method with proper rule statements in improper
  2768 proof *scripts*;
  2769 
  2770 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2771 now consider the syntactic context of assumptions, giving a better
  2772 chance to get type-inference of the arguments right (this is
  2773 especially important for locales);
  2774 
  2775 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2776 mode;
  2777 
  2778 * Pure/obtain: the formal conclusion "thesis", being marked as
  2779 ``internal'', may no longer be reference directly in the text;
  2780 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2781 situations;
  2782 
  2783 * Pure: generic 'sym' attribute which declares a rule both as pure
  2784 'elim?' and for the 'symmetric' operation;
  2785 
  2786 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2787 text; the fixed correlation with particular command syntax has been
  2788 discontinued;
  2789 
  2790 * Pure: new method 'rules' is particularly well-suited for proof
  2791 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2792 but often produces more compact proof terms with less detours;
  2793 
  2794 * Pure/Provers/classical: simplified integration with pure rule
  2795 attributes and methods; the classical "intro?/elim?/dest?"
  2796 declarations coincide with the pure ones; the "rule" method no longer
  2797 includes classically swapped intros; "intro" and "elim" methods no
  2798 longer pick rules from the context; also got rid of ML declarations
  2799 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2800 INCOMPATIBILITY;
  2801 
  2802 * Provers/classical: attribute 'swapped' produces classical inversions
  2803 of introduction rules;
  2804 
  2805 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2806 rules instead of full simplifier context; 'iff' attribute handles
  2807 conditional rules;
  2808 
  2809 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2810 
  2811 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2812 "(permissive)" option to recover old behavior;
  2813 
  2814 * HOL: 'inductive' no longer features separate (collective) attributes
  2815 for 'intros' (was found too confusing);
  2816 
  2817 * HOL: properly declared induction rules less_induct and
  2818 wf_induct_rule;
  2819 
  2820 
  2821 *** HOL ***
  2822 
  2823 * HOL: moved over to sane numeral syntax; the new policy is as
  2824 follows:
  2825 
  2826   - 0 and 1 are polymorphic constants, which are defined on any
  2827   numeric type (nat, int, real etc.);
  2828 
  2829   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2830   binary representation internally;
  2831 
  2832   - type nat has special constructor Suc, and generally prefers Suc 0
  2833   over 1::nat and Suc (Suc 0) over 2::nat;
  2834 
  2835 This change may cause significant problems of INCOMPATIBILITY; here
  2836 are some hints on converting existing sources:
  2837 
  2838   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2839   entities, so expressions involving "-" (unary or binary minus) need
  2840   to be spaced properly;
  2841 
  2842   - existing occurrences of "1" may need to be constraint "1::nat" or
  2843   even replaced by Suc 0; similar for old "2";
  2844 
  2845   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2846 
  2847   - remove all special provisions on numerals in proofs;
  2848 
  2849 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2850 representation (depends on bin_arith_simps in the default context);
  2851 
  2852 * HOL: symbolic syntax for x^2 (numeral 2);
  2853 
  2854 * HOL: the class of all HOL types is now called "type" rather than
  2855 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2856 in axclass/classes, instance/arities, and (usually rare) occurrences
  2857 in typings (of consts etc.); internally the class is called
  2858 "HOL.type", ML programs should refer to HOLogic.typeS;
  2859 
  2860 * HOL/record package improvements:
  2861   - new derived operations "fields" to build a partial record section,
  2862     "extend" to promote a fixed record to a record scheme, and
  2863     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2864     declared as simp by default;
  2865   - shared operations ("more", "fields", etc.) now need to be always
  2866     qualified) --- potential INCOMPATIBILITY;
  2867   - removed "make_scheme" operations (use "make" with "extend") --
  2868     INCOMPATIBILITY;
  2869   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2870   - provides cases/induct rules for use with corresponding Isar
  2871     methods (for concrete records, record schemes, concrete more
  2872     parts, and schematic more parts -- in that order);
  2873   - internal definitions directly based on a light-weight abstract
  2874     theory of product types over typedef rather than datatype;
  2875 
  2876 * HOL: generic code generator for generating executable ML code from
  2877 specifications; specific support for HOL constructs such as inductive
  2878 datatypes and sets, as well as recursive functions; can be invoked
  2879 via 'generate_code' theory section;
  2880 
  2881 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2882 
  2883 * HOL: consolidated and renamed several theories.  In particular:
  2884         Ord.thy has been absorbed into HOL.thy
  2885         String.thy has been absorbed into List.thy
  2886 
  2887 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2888 (beware of argument permutation!);
  2889 
  2890 * HOL: linorder_less_split superseded by linorder_cases;
  2891 
  2892 * HOL/List: "nodups" renamed to "distinct";
  2893 
  2894 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2895 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2896   - Ex_def has changed, now need to use some_eq_ex
  2897 
  2898 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2899 in this (rare) case use:
  2900 
  2901   delSWrapper "split_all_tac"
  2902   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2903 
  2904 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2905 MAY FAIL;
  2906 
  2907 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2908 Isabelle's type classes, ^ on functions and relations has too general
  2909 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2910 necessary to attach explicit type constraints;
  2911 
  2912 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2913 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2914 renamed accordingly (eg "compI" -> "rel_compI").
  2915 
  2916 * HOL: syntax translations now work properly with numerals and records
  2917 expressions;
  2918 
  2919 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2920 of "lam" -- INCOMPATIBILITY;
  2921 
  2922 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2923 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2924 renamed "Product_Type.unit";
  2925 
  2926 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2927 
  2928 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2929 the "cases" method);
  2930 
  2931 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2932 Florian Kammller);
  2933 
  2934 * HOL/IMP: updated and converted to new-style theory format; several
  2935 parts turned into readable document, with proper Isar proof texts and
  2936 some explanations (by Gerwin Klein);
  2937 
  2938 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2939 
  2940 * HOL-Hyperreal is now a logic image;
  2941 
  2942 
  2943 *** HOLCF ***
  2944 
  2945 * Isar: consts/constdefs supports mixfix syntax for continuous
  2946 operations;
  2947 
  2948 * Isar: domain package adapted to new-style theory format, e.g. see
  2949 HOLCF/ex/Dnat.thy;
  2950 
  2951 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2952 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2953 lift.induct_tac, always use UU instead of Undef;
  2954 
  2955 * HOLCF/IMP: updated and converted to new-style theory;
  2956 
  2957 
  2958 *** ZF ***
  2959 
  2960 * Isar: proper integration of logic-specific tools and packages,
  2961 including theory commands '(co)inductive', '(co)datatype',
  2962 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2963 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2964 
  2965 * theory Main no longer includes AC; for the Axiom of Choice, base
  2966 your theory on Main_ZFC;
  2967 
  2968 * the integer library now covers quotients and remainders, with many
  2969 laws relating division to addition, multiplication, etc.;
  2970 
  2971 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2972 typeless version of the formalism;
  2973 
  2974 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2975 format;
  2976 
  2977 * ZF/Induct: new directory for examples of inductive definitions,
  2978 including theory Multiset for multiset orderings; converted to
  2979 new-style theory format;
  2980 
  2981 * ZF: many new theorems about lists, ordinals, etc.;
  2982 
  2983 
  2984 *** General ***
  2985 
  2986 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2987 variable proof controls level of detail: 0 = no proofs (only oracle
  2988 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2989 also ref manual for further ML interfaces;
  2990 
  2991 * Pure/axclass: removed obsolete ML interface
  2992 goal_subclass/goal_arity;
  2993 
  2994 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2995 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2996 separate tokens, so expressions involving minus need to be spaced
  2997 properly;
  2998 
  2999 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3000 rather than "infixl" or "infixr";
  3001 
  3002 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3003 sort constraint specifications in type inference; e.g. "x::_::foo"
  3004 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3005 type variable);
  3006 
  3007 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3008 control output of nested => (types); the default behavior is
  3009 "type_brackets";
  3010 
  3011 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3012 tokens into AST constants;
  3013 
  3014 * Pure/syntax: prefer later declarations of translations and print
  3015 translation functions; potential INCOMPATIBILITY: need to reverse
  3016 multiple declarations for same syntax element constant;
  3017 
  3018 * Pure/show_hyps reset by default (in accordance to existing Isar
  3019 practice);
  3020 
  3021 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3022 addSafter;
  3023 
  3024 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3025 as well;
  3026 
  3027 * system: tested support for MacOS X; should be able to get Isabelle +
  3028 Proof General to work in a plain Terminal after installing Poly/ML
  3029 (e.g. from the Isabelle distribution area) and GNU bash alone
  3030 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3031 support requires further installations, e.g. from
  3032 http://fink.sourceforge.net/);
  3033 
  3034 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3035 
  3036 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3037 of 40 MB), cf. ML_OPTIONS;
  3038 
  3039 * system: Proof General keywords specification is now part of the
  3040 Isabelle distribution (see etc/isar-keywords.el);
  3041 
  3042 * system: support for persistent Proof General sessions (refrain from
  3043 outdating all loaded theories on startup); user may create writable
  3044 logic images like this: ``isabelle -q HOL Test'';
  3045 
  3046 * system: smart selection of Isabelle process versus Isabelle
  3047 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3048 run both "isabelle" and "Isabelle" even if file names are badly
  3049 damaged (executable inspects the case of the first letter of its own
  3050 name); added separate "isabelle-process" and "isabelle-interface";
  3051 
  3052 * system: refrain from any attempt at filtering input streams; no
  3053 longer support ``8bit'' encoding of old isabelle font, instead proper
  3054 iso-latin characters may now be used; the related isatools
  3055 "symbolinput" and "nonascii" have disappeared as well;
  3056 
  3057 * system: removed old "xterm" interface (the print modes "xterm" and
  3058 "xterm_color" are still available for direct use in a suitable
  3059 terminal);
  3060 
  3061 
  3062 
  3063 New in Isabelle99-2 (February 2001)
  3064 -----------------------------------
  3065 
  3066 *** Overview of INCOMPATIBILITIES ***
  3067 
  3068 * HOL: please note that theories in the Library and elsewhere often use the
  3069 new-style (Isar) format; to refer to their theorems in an ML script you must
  3070 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3071 
  3072 * HOL: inductive package no longer splits induction rule aggressively,
  3073 but only as far as specified by the introductions given; the old
  3074 format may be recovered via ML function complete_split_rule or attribute
  3075 'split_rule (complete)';
  3076 
  3077 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3078 gfp_Tarski to gfp_unfold;
  3079 
  3080 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3081 
  3082 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3083 relation); infix "^^" has been renamed "``"; infix "``" has been
  3084 renamed "`"; "univalent" has been renamed "single_valued";
  3085 
  3086 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3087 operation;
  3088 
  3089 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3090 
  3091 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3092 
  3093 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3094 consequence, it is no longer monotonic wrt. the local goal context
  3095 (which is now passed through the inductive cases);
  3096 
  3097 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3098 \<gg> to \<ggreater>;
  3099 
  3100 
  3101 *** Document preparation ***
  3102 
  3103 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3104 available: are "it" for near math-mode best-style output, "sl" for
  3105 slanted text style, and "tt" for plain type-writer; if no
  3106 \isabellestyle command is given, output is according to slanted
  3107 type-writer);
  3108 
  3109 * support sub/super scripts (for single symbols only), input syntax is
  3110 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3111 
  3112 * some more standard symbols; see Appendix A of the system manual for
  3113 the complete list of symbols defined in isabellesym.sty;
  3114 
  3115 * improved isabelle style files; more abstract symbol implementation
  3116 (should now use \isamath{...} and \isatext{...} in custom symbol
  3117 definitions);
  3118 
  3119 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3120 state; Note that presentation of goal states does not conform to
  3121 actual human-readable proof documents.  Please do not include goal
  3122 states into document output unless you really know what you are doing!
  3123 
  3124 * proper indentation of antiquoted output with proportional LaTeX
  3125 fonts;
  3126 
  3127 * no_document ML operator temporarily disables LaTeX document
  3128 generation;
  3129 
  3130 * isatool unsymbolize tunes sources for plain ASCII communication;
  3131 
  3132 
  3133 *** Isar ***
  3134 
  3135 * Pure: Isar now suffers initial goal statements to contain unbound
  3136 schematic variables (this does not conform to actual readable proof
  3137 documents, due to unpredictable outcome and non-compositional proof
  3138 checking); users who know what they are doing may use schematic goals
  3139 for Prolog-style synthesis of proven results;
  3140 
  3141 * Pure: assumption method (an implicit finishing) now handles actual
  3142 rules as well;
  3143 
  3144 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3145 initial goal, declare "that" only as Pure intro (only for single
  3146 steps); the "that" rule assumption may now be involved in implicit
  3147 finishing, thus ".." becomes a feasible for trivial obtains;
  3148 
  3149 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3150 instance proofs may be performed by "..";
  3151 
  3152 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3153 statements as well;
  3154 
  3155 * Pure: more robust selection of calculational rules;
  3156 
  3157 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3158 rule (as well as the assumption rule);
  3159 
  3160 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3161 lemmas, using the graph browser tool;
  3162 
  3163 * Pure: predict failure of "show" in interactive mode;
  3164 
  3165 * Pure: 'thms_containing' now takes actual terms as arguments;
  3166 
  3167 * HOL: improved method 'induct' --- now handles non-atomic goals
  3168 (potential INCOMPATIBILITY); tuned error handling;
  3169 
  3170 * HOL: cases and induct rules now provide explicit hints about the
  3171 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3172 any remaining facts are inserted into the goal verbatim;
  3173 
  3174 * HOL: local contexts (aka cases) may now contain term bindings as
  3175 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3176 the result to be shown in each case;
  3177 
  3178 * HOL: added 'recdef_tc' command;
  3179 
  3180 * isatool convert assists in eliminating legacy ML scripts;
  3181 
  3182 
  3183 *** HOL ***
  3184 
  3185 * HOL/Library: a collection of generic theories to be used together
  3186 with main HOL; the theory loader path already includes this directory
  3187 by default; the following existing theories have been moved here:
  3188 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3189 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3190 
  3191 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3192 modelling and verification task performed in Isabelle/HOL +
  3193 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3194 
  3195 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3196 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3197 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3198 'domain', this makes the theory consistent with mathematical
  3199 literature;
  3200 
  3201 * HOL basics: added overloaded operations "inverse" and "divide"
  3202 (infix "/"), syntax for generic "abs" operation, generic summation
  3203 operator \<Sum>;
  3204 
  3205 * HOL/typedef: simplified package, provide more useful rules (see also
  3206 HOL/subset.thy);
  3207 
  3208 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3209 now expressed as a proper nested rule (old-style tactic scripts may
  3210 require atomize_strip_tac to cope with non-atomic premises);
  3211 
  3212 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3213 to "split_conv" (old name still available for compatibility);
  3214 
  3215 * HOL: improved concrete syntax for strings (e.g. allows translation
  3216 rules with string literals);
  3217 
  3218 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3219  and Fleuriot's mechanization of analysis, including the transcendental
  3220  functions for the reals;
  3221 
  3222 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3223 
  3224 
  3225 *** CTT ***
  3226 
  3227 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3228 "lam" is displayed as TWO lambda-symbols
  3229 
  3230 * CTT: theory Main now available, containing everything (that is, Bool
  3231 and Arith);
  3232 
  3233 
  3234 *** General ***
  3235 
  3236 * Pure: the Simplifier has been implemented properly as a derived rule
  3237 outside of the actual kernel (at last!); the overall performance
  3238 penalty in practical applications is about 50%, while reliability of
  3239 the Isabelle inference kernel has been greatly improved;
  3240 
  3241 * print modes "brackets" and "no_brackets" control output of nested =>
  3242 (types) and ==> (props); the default behaviour is "brackets";
  3243 
  3244 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3245 as assumptions as well;
  3246 
  3247 * system: support Poly/ML 4.0;
  3248 
  3249 * system: isatool install handles KDE version 1 or 2;
  3250 
  3251 
  3252 
  3253 New in Isabelle99-1 (October 2000)
  3254 ----------------------------------
  3255 
  3256 *** Overview of INCOMPATIBILITIES ***
  3257 
  3258 * HOL: simplification of natural numbers is much changed; to partly
  3259 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3260 issue the following ML commands:
  3261 
  3262   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3263   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3264 
  3265 * HOL: simplification no longer dives into case-expressions; this is
  3266 controlled by "t.weak_case_cong" for each datatype t;
  3267 
  3268 * HOL: nat_less_induct renamed to less_induct;
  3269 
  3270 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3271 fixsome to patch .thy and .ML sources automatically;
  3272 
  3273   select_equality  -> some_equality
  3274   select_eq_Ex     -> some_eq_ex
  3275   selectI2EX       -> someI2_ex
  3276   selectI2         -> someI2
  3277   selectI          -> someI
  3278   select1_equality -> some1_equality
  3279   Eps_sym_eq       -> some_sym_eq_trivial
  3280   Eps_eq           -> some_eq_trivial
  3281 
  3282 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3283 
  3284 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3285 instead);
  3286 
  3287 * HOL: the recursion equations generated by 'recdef' are now called
  3288 f.simps instead of f.rules;
  3289 
  3290 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3291 
  3292 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3293 sometimes be needed;
  3294 
  3295 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3296 
  3297 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3298 
  3299 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3300 product is now "<*>" instead of "Times"; the lexicographic product is
  3301 now "<*lex*>" instead of "**";
  3302 
  3303 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3304 of main HOL, but was unused); better use HOL's datatype package;
  3305 
  3306 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3307 the old syntax may be recovered as follows:
  3308 
  3309   syntax (symbols)
  3310     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3311       (infixl "\\<oplus>" 100)
  3312 
  3313 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3314 
  3315 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3316 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3317 internally;
  3318 
  3319 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3320 changed from A/r to A//r;
  3321 
  3322 * ZF: new treatment of arithmetic (nat & int) may break some old
  3323 proofs;
  3324 
  3325 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3326 rulify -> rule_format, elimify -> elim_format, ...);
  3327 
  3328 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3329 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3330 should have to change intro!! to intro? only); replaced "delrule" by
  3331 "rule del";
  3332 
  3333 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3334 
  3335 * Provers: strengthened force_tac by using new first_best_tac;
  3336 
  3337 * LaTeX document preparation: several changes of isabelle.sty (see
  3338 lib/texinputs);
  3339 
  3340 
  3341 *** Document preparation ***
  3342 
  3343 * formal comments (text blocks etc.) in new-style theories may now
  3344 contain antiquotations of thm/prop/term/typ/text to be presented
  3345 according to latex print mode; concrete syntax is like this:
  3346 @{term[show_types] "f(x) = a + x"};
  3347 
  3348 * isatool mkdir provides easy setup of Isabelle session directories,
  3349 including proper document sources;
  3350 
  3351 * generated LaTeX sources are now deleted after successful run
  3352 (isatool document -c); may retain a copy somewhere else via -D option
  3353 of isatool usedir;
  3354 
  3355 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3356 style files, achieving self-contained LaTeX sources and simplifying
  3357 LaTeX debugging;
  3358 
  3359 * old-style theories now produce (crude) LaTeX output as well;
  3360 
  3361 * browser info session directories are now self-contained (may be put
  3362 on WWW server seperately); improved graphs of nested sessions; removed
  3363 graph for 'all sessions';
  3364 
  3365 * several improvements in isabelle style files; \isabellestyle{it}
  3366 produces fake math mode output; \isamarkupheader is now \section by
  3367 default; see lib/texinputs/isabelle.sty etc.;
  3368 
  3369 
  3370 *** Isar ***
  3371 
  3372 * Isar/Pure: local results and corresponding term bindings are now
  3373 subject to Hindley-Milner polymorphism (similar to ML); this
  3374 accommodates incremental type-inference very nicely;
  3375 
  3376 * Isar/Pure: new derived language element 'obtain' supports
  3377 generalized existence reasoning;
  3378 
  3379 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3380 support accumulation of results, without applying any rules yet;
  3381 useful to collect intermediate results without explicit name
  3382 references, and for use with transitivity rules with more than 2
  3383 premises;
  3384 
  3385 * Isar/Pure: scalable support for case-analysis type proofs: new
  3386 'case' language element refers to local contexts symbolically, as
  3387 produced by certain proof methods; internally, case names are attached
  3388 to theorems as "tags";
  3389 
  3390 * Isar/Pure: theory command 'hide' removes declarations from
  3391 class/type/const name spaces;
  3392 
  3393 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3394 indicate potential overloading;
  3395 
  3396 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3397 
  3398 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3399 "{a,b,c}" instead of {a,b,c};
  3400 
  3401 * Isar/Pure now provides its own version of intro/elim/dest
  3402 attributes; useful for building new logics, but beware of confusion
  3403 with the version in Provers/classical;
  3404 
  3405 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3406 case name 'antecedent';
  3407 
  3408 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3409 to the current context is now done automatically);
  3410 
  3411 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3412 for definining proof methods in ML;
  3413 
  3414 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3415 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3416 most cases, one should have to change intro!! to intro? only);
  3417 replaced "delrule" by "rule del";
  3418 
  3419 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3420 'symmetric' attribute (the latter supercedes [RS sym]);
  3421 
  3422 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3423 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3424 well (including splits);
  3425 
  3426 * Isar/Provers: Simplifier and Classical methods now support all kind
  3427 of modifiers used in the past, including 'cong', 'iff', etc.
  3428 
  3429 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3430 of Simplifier and Classical reasoner);
  3431 
  3432 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3433 now support named cases; major packages (inductive, datatype, primrec,
  3434 recdef) support case names and properly name parameters;
  3435 
  3436 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3437 monotonicity conditions are extracted to be proven at end of
  3438 calculations;
  3439 
  3440 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3441 method anyway;
  3442 
  3443 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3444 split_if split_if_asm; datatype package provides theorems foo.splits =
  3445 foo.split foo.split_asm for each datatype;
  3446 
  3447 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3448 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3449 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3450 use "(cases (simplified))" method in proper proof texts);
  3451 
  3452 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3453 
  3454 * Isar: names of theorems etc. may be natural numbers as well;
  3455 
  3456 * Isar: 'pr' command: optional arguments for goals_limit and
  3457 ProofContext.prems_limit; no longer prints theory contexts, but only
  3458 proof states;
  3459 
  3460 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3461 additional print modes to be specified; e.g. "pr(latex)" will print
  3462 proof state according to the Isabelle LaTeX style;
  3463 
  3464 * Isar: improved support for emulating tactic scripts, including proof
  3465 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3466 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3467 (for HOL datatypes);
  3468 
  3469 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3470 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3471 'proof method scripts' have to be in depth-first order;
  3472 
  3473 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3474 
  3475 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3476 should instead use individual commands for printing items
  3477 (print_commands, print_methods etc.);
  3478 
  3479 * Isar: added 'nothing' --- the empty list of theorems;
  3480 
  3481 
  3482 *** HOL ***
  3483 
  3484 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3485 corresponding virtual machine and a specification of its bytecode
  3486 verifier and a lightweight bytecode verifier, including proofs of
  3487 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3488 Cornelia Pusch (see also the homepage of project Bali at
  3489 http://isabelle.in.tum.de/Bali/);
  3490 
  3491 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3492 Clemens Ballarin;
  3493 
  3494 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3495 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3496 Rasmussen;
  3497 
  3498 * HOL/Lattice: fundamental concepts of lattice theory and order
  3499 structures, including duals, properties of bounds versus algebraic
  3500 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3501 Theorem for complete lattices etc.; may also serve as a demonstration
  3502 for abstract algebraic reasoning using axiomatic type classes, and
  3503 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3504 
  3505 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3506 von Oheimb;
  3507 
  3508 * HOL/IMPP: extension of IMP with local variables and mutually
  3509 recursive procedures, by David von Oheimb;
  3510 
  3511 * HOL/Lambda: converted into new-style theory and document;
  3512 
  3513 * HOL/ex/Multiquote: example of multiple nested quotations and
  3514 anti-quotations -- basically a generalized version of de-Bruijn
  3515 representation; very useful in avoiding lifting of operations;
  3516 
  3517 * HOL/record: added general record equality rule to simpset; fixed
  3518 select-update simplification procedure to handle extended records as
  3519 well; admit "r" as field name;
  3520 
  3521 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3522 other numeric types and also as the identity of groups, rings, etc.;
  3523 
  3524 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3525 Types nat and int belong to this axclass;
  3526 
  3527 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3528    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3529    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3530   two terms #m*u and #n*u are replaced by #(m+n)*u
  3531     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3532   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3533     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3534 
  3535 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3536 powerful prover for predicate logic but knows nothing of clasets; see
  3537 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3538 
  3539 * HOL: new version of "case_tac" subsumes both boolean case split and
  3540 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3541 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3542 
  3543 * HOL: simplification no longer dives into case-expressions: only the
  3544 selector expression is simplified, but not the remaining arms; to
  3545 enable full simplification of case-expressions for datatype t, you may
  3546 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3547 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3548 
  3549 * HOL/recdef: the recursion equations generated by 'recdef' for
  3550 function 'f' are now called f.simps instead of f.rules; if all
  3551 termination conditions are proved automatically, these simplification
  3552 rules are added to the simpset, as in primrec; rules may be named
  3553 individually as well, resulting in a separate list of theorems for
  3554 each equation;
  3555 
  3556 * HOL/While is a new theory that provides a while-combinator. It
  3557 permits the definition of tail-recursive functions without the
  3558 provision of a termination measure. The latter is necessary once the
  3559 invariant proof rule for while is applied.
  3560 
  3561 * HOL: new (overloaded) notation for the set of elements below/above
  3562 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3563 
  3564 * HOL: theorems impI, allI, ballI bound as "strip";
  3565 
  3566 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3567 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3568 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3569 
  3570 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3571 
  3572 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3573 main HOL, but was unused);
  3574 
  3575 * HOL: fewer consts declared as global (e.g. have to refer to
  3576 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3577 
  3578 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3579 in case of overlap with user translations (e.g. judgements over
  3580 tuples); (note that the underlying logical represenation is still
  3581 bogus);
  3582 
  3583 
  3584 *** ZF ***
  3585 
  3586 * ZF: simplification automatically cancels common terms in arithmetic
  3587 expressions over nat and int;
  3588 
  3589 * ZF: new treatment of nat to minimize type-checking: all operators
  3590 coerce their operands to a natural number using the function natify,
  3591 making the algebraic laws unconditional;
  3592 
  3593 * ZF: as above, for int: operators coerce their operands to an integer
  3594 using the function intify;
  3595 
  3596 * ZF: the integer library now contains many of the usual laws for the
  3597 orderings, including $<=, and monotonicity laws for $+ and $*;
  3598 
  3599 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3600 simplification;
  3601 
  3602 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3603 to the simplifier and classical reasoner simultaneously;
  3604 
  3605 
  3606 *** General ***
  3607 
  3608 * Provers: blast_tac now handles actual object-logic rules as
  3609 assumptions; note that auto_tac uses blast_tac internally as well;
  3610 
  3611 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3612 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3613 
  3614 * Provers: delrules now handles destruct rules as well (no longer need
  3615 explicit make_elim);
  3616 
  3617 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3618   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3619 use instead the strong form,
  3620   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3621 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3622 from destruct-rules;
  3623 
  3624 * Provers: Simplifier.easy_setup provides a fast path to basic
  3625 Simplifier setup for new object-logics;
  3626 
  3627 * Pure: AST translation rules no longer require constant head on LHS;
  3628 
  3629 * Pure: improved name spaces: ambiguous output is qualified; support
  3630 for hiding of names;
  3631 
  3632 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3633 XSYMBOL_HOME; no longer need to do manual configuration in most
  3634 situations;
  3635 
  3636 * system: compression of ML heaps images may now be controlled via -c
  3637 option of isabelle and isatool usedir (currently only observed by
  3638 Poly/ML);
  3639 
  3640 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3641 useful for remote X11);
  3642 
  3643 * system: provide TAGS file for Isabelle sources;
  3644 
  3645 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3646 order;
  3647 
  3648 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3649 timing flag supersedes proof_timing and Toplevel.trace;
  3650 
  3651 * ML: new combinators |>> and |>>> for incremental transformations
  3652 with secondary results (e.g. certain theory extensions):
  3653 
  3654 * ML: PureThy.add_defs gets additional argument to indicate potential
  3655 overloading (usually false);
  3656 
  3657 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3658 results;
  3659 
  3660 
  3661 
  3662 New in Isabelle99 (October 1999)
  3663 --------------------------------
  3664 
  3665 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3666 
  3667 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3668 are no longer simplified.  (This allows the simplifier to unfold recursive
  3669 functional programs.)  To restore the old behaviour, declare
  3670 
  3671     Delcongs [if_weak_cong];
  3672 
  3673 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3674 complement;
  3675 
  3676 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3677 
  3678 * HOL/datatype: mutual_induct_tac no longer exists --
  3679   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3680 
  3681 * HOL/typedef: fixed type inference for representing set; type
  3682 arguments now have to occur explicitly on the rhs as type constraints;
  3683 
  3684 * ZF: The con_defs part of an inductive definition may no longer refer
  3685 to constants declared in the same theory;
  3686 
  3687 * HOL, ZF: the function mk_cases, generated by the inductive
  3688 definition package, has lost an argument.  To simplify its result, it
  3689 uses the default simpset instead of a supplied list of theorems.
  3690 
  3691 * HOL/List: the constructors of type list are now Nil and Cons;
  3692 
  3693 * Simplifier: the type of the infix ML functions
  3694         setSSolver addSSolver setSolver addSolver
  3695 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3696 for packaging solvers. A solver is created via
  3697         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3698 where the string argument is only a comment.
  3699 
  3700 
  3701 *** Proof tools ***
  3702 
  3703 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3704 decision procedure for linear arithmetic. Currently it is used for
  3705 types `nat', `int', and `real' in HOL (see below); it can, should and
  3706 will be instantiated for other types and logics as well.
  3707 
  3708 * The simplifier now accepts rewrite rules with flexible heads, eg
  3709      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3710   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3711   matching.
  3712 
  3713 
  3714 *** General ***
  3715 
  3716 * New Isabelle/Isar subsystem provides an alternative to traditional
  3717 tactical theorem proving; together with the ProofGeneral/isar user
  3718 interface it offers an interactive environment for developing human
  3719 readable proof documents (Isar == Intelligible semi-automated
  3720 reasoning); for further information see isatool doc isar-ref,
  3721 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3722 
  3723 * improved and simplified presentation of theories: better HTML markup
  3724 (including colors), graph views in several sizes; isatool usedir now
  3725 provides a proper interface for user theories (via -P option); actual
  3726 document preparation based on (PDF)LaTeX is available as well (for
  3727 new-style theories only); see isatool doc system for more information;
  3728 
  3729 * native support for Proof General, both for classic Isabelle and
  3730 Isabelle/Isar;
  3731 
  3732 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3733 using the graph browser tool;
  3734 
  3735 * Isabelle manuals now also available as PDF;
  3736 
  3737 * theory loader rewritten from scratch (may not be fully
  3738 bug-compatible); old loadpath variable has been replaced by show_path,
  3739 add_path, del_path, reset_path functions; new operations such as
  3740 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3741 isatool doc ref);
  3742 
  3743 * improved isatool install: option -k creates KDE application icon,
  3744 option -p DIR installs standalone binaries;
  3745 
  3746 * added ML_PLATFORM setting (useful for cross-platform installations);
  3747 more robust handling of platform specific ML images for SML/NJ;
  3748 
  3749 * the settings environment is now statically scoped, i.e. it is never
  3750 created again in sub-processes invoked from isabelle, isatool, or
  3751 Isabelle;
  3752 
  3753 * path element specification '~~' refers to '$ISABELLE_HOME';
  3754 
  3755 * in locales, the "assumes" and "defines" parts may be omitted if
  3756 empty;
  3757 
  3758 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3759 long arrows);
  3760 
  3761 * new print_mode "HTML";
  3762 
  3763 * new flag show_tags controls display of tags of theorems (which are
  3764 basically just comments that may be attached by some tools);
  3765 
  3766 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3767 mode and goal output format:
  3768 
  3769 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3770 244c244
  3771 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3772 ---
  3773 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3774 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3775 181c181
  3776 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3777 ---
  3778 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3779 
  3780 * function bind_thms stores lists of theorems (cf. bind_thm);
  3781 
  3782 * new shorthand tactics ftac, eatac, datac, fatac;
  3783 
  3784 * qed (and friends) now accept "" as result name; in that case the
  3785 theorem is not stored, but proper checks and presentation of the
  3786 result still apply;
  3787 
  3788 * theorem database now also indexes constants "Trueprop", "all",
  3789 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3790 
  3791 
  3792 *** HOL ***
  3793 
  3794 ** HOL arithmetic **
  3795 
  3796 * There are now decision procedures for linear arithmetic over nat and
  3797 int:
  3798 
  3799 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3800 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3801 are treated as atomic; subformulae not involving type `nat' or `int'
  3802 are ignored; quantified subformulae are ignored unless they are
  3803 positive universal or negative existential. The tactic has to be
  3804 invoked by hand and can be a little bit slow. In particular, the
  3805 running time is exponential in the number of occurrences of `min' and
  3806 `max', and `-' on `nat'.
  3807 
  3808 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3809 (negated) (in)equalities among the premises and the conclusion into
  3810 account (i.e. no compound formulae) and does not know about `min' and
  3811 `max', and `-' on `nat'. It is fast and is used automatically by the
  3812 simplifier.
  3813 
  3814 NB: At the moment, these decision procedures do not cope with mixed
  3815 nat/int formulae where the two parts interact, such as `m < n ==>
  3816 int(m) < int(n)'.
  3817 
  3818 * HOL/Numeral provides a generic theory of numerals (encoded
  3819 efficiently as bit strings); setup for types nat/int/real is in place;
  3820 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3821 int, existing theories and proof scripts may require a few additional
  3822 type constraints;
  3823 
  3824 * integer division and remainder can now be performed on constant
  3825 arguments;
  3826 
  3827 * many properties of integer multiplication, division and remainder
  3828 are now available;
  3829 
  3830 * An interface to the Stanford Validity Checker (SVC) is available through the
  3831 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3832 are proved automatically.  SVC must be installed separately, and its results
  3833 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3834 invocation of the underlying oracle).  For SVC see
  3835   http://verify.stanford.edu/SVC
  3836 
  3837 * IsaMakefile: the HOL-Real target now builds an actual image;
  3838 
  3839 
  3840 ** HOL misc **
  3841 
  3842 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3843 (in Isabelle/Isar) -- by Gertrud Bauer;
  3844 
  3845 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3846 analysis for assembly languages with subtypes;
  3847 
  3848 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3849 -- avoids syntactic ambiguities and treats state, transition, and
  3850 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3851 changed syntax and (many) tactics;
  3852 
  3853 * HOL/inductive: Now also handles more general introduction rules such
  3854   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3855   theorems are now maintained within the theory (maintained via the
  3856   "mono" attribute);
  3857 
  3858 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3859   (using function types) such as
  3860 
  3861   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3862 
  3863 * HOL/record: record_simproc (part of the default simpset) takes care
  3864 of selectors applied to updated records; record_split_tac is no longer
  3865 part of the default claset; update_defs may now be removed from the
  3866 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3867 
  3868   claset_ref () := claset() addSWrapper record_split_wrapper;
  3869   Delsimprocs [record_simproc]
  3870 
  3871 * HOL/typedef: fixed type inference for representing set; type
  3872 arguments now have to occur explicitly on the rhs as type constraints;
  3873 
  3874 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3875 names rather than an ML expression;
  3876 
  3877 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3878 supplied later.  Program schemes can be defined, such as
  3879     "While B C s = (if B s then While B C (C s) else s)"
  3880 where the well-founded relation can be chosen after B and C have been given.
  3881 
  3882 * HOL/List: the constructors of type list are now Nil and Cons;
  3883 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3884 course, ML tools referring to List.list.op # etc. have to be adapted;
  3885 
  3886 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3887 disabled by default; run isabelle with option -m HOL to get back to
  3888 the original Gordon/HOL-style output;
  3889 
  3890 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3891 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3892 
  3893 * HOL basic syntax simplified (more orthogonal): all variants of
  3894 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3895 Eps operator is provided as well: "SOME x. P[x]";
  3896 
  3897 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3898 
  3899 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3900 thus available for user theories;
  3901 
  3902 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3903 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3904 time;
  3905 
  3906 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3907 several times and then mp;
  3908 
  3909 
  3910 *** LK ***
  3911 
  3912 * the notation <<...>> is now available as a notation for sequences of
  3913 formulas;
  3914 
  3915 * the simplifier is now installed
  3916 
  3917 * the axiom system has been generalized (thanks to Soren Heilmann)
  3918 
  3919 * the classical reasoner now has a default rule database
  3920 
  3921 
  3922 *** ZF ***
  3923 
  3924 * new primrec section allows primitive recursive functions to be given
  3925 directly (as in HOL) over datatypes and the natural numbers;
  3926 
  3927 * new tactics induct_tac and exhaust_tac for induction (or case
  3928 analysis) over datatypes and the natural numbers;
  3929 
  3930 * the datatype declaration of type T now defines the recursor T_rec;
  3931 
  3932 * simplification automatically does freeness reasoning for datatype
  3933 constructors;
  3934 
  3935 * automatic type-inference, with AddTCs command to insert new
  3936 type-checking rules;
  3937 
  3938 * datatype introduction rules are now added as Safe Introduction rules
  3939 to the claset;
  3940 
  3941 * the syntax "if P then x else y" is now available in addition to
  3942 if(P,x,y);
  3943 
  3944 
  3945 *** Internal programming interfaces ***
  3946 
  3947 * tuned simplifier trace output; new flag debug_simp;
  3948 
  3949 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3950 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3951 
  3952 * AxClass.axclass_tac lost the theory argument;
  3953 
  3954 * tuned current_goals_markers semantics: begin / end goal avoids
  3955 printing empty lines;
  3956 
  3957 * removed prs and prs_fn hook, which was broken because it did not
  3958 include \n in its semantics, forcing writeln to add one
  3959 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3960 string -> unit if you really want to output text without newline;
  3961 
  3962 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3963 plain output, interface builders may have to enable 'isabelle_font'
  3964 mode to get Isabelle font glyphs as before;
  3965 
  3966 * refined token_translation interface; INCOMPATIBILITY: output length
  3967 now of type real instead of int;
  3968 
  3969 * theory loader actions may be traced via new ThyInfo.add_hook
  3970 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3971 your own database of information attached to *whole* theories -- as
  3972 opposed to intra-theory data slots offered via TheoryDataFun;
  3973 
  3974 * proper handling of dangling sort hypotheses (at last!);
  3975 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3976 extra sort hypotheses that can be witnessed from the type signature;
  3977 the force_strip_shyps flag is gone, any remaining shyps are simply
  3978 left in the theorem (with a warning issued by strip_shyps_warning);
  3979 
  3980 
  3981 
  3982 New in Isabelle98-1 (October 1998)
  3983 ----------------------------------
  3984 
  3985 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3986 
  3987 * several changes of automated proof tools;
  3988 
  3989 * HOL: major changes to the inductive and datatype packages, including
  3990 some minor incompatibilities of theory syntax;
  3991 
  3992 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3993 called `inj_on';
  3994 
  3995 * HOL: removed duplicate thms in Arith:
  3996   less_imp_add_less  should be replaced by  trans_less_add1
  3997   le_imp_add_le      should be replaced by  trans_le_add1
  3998 
  3999 * HOL: unary minus is now overloaded (new type constraints may be
  4000 required);
  4001 
  4002 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4003 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4004 now taken as an integer constant.
  4005 
  4006 * Pure: ML function 'theory_of' renamed to 'theory';
  4007 
  4008 
  4009 *** Proof tools ***
  4010 
  4011 * Simplifier:
  4012   1. Asm_full_simp_tac is now more aggressive.
  4013      1. It will sometimes reorient premises if that increases their power to
  4014         simplify.
  4015      2. It does no longer proceed strictly from left to right but may also
  4016         rotate premises to achieve further simplification.
  4017      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4018      old Asm_full_simp_tac in that it does not rotate premises.
  4019   2. The simplifier now knows a little bit about nat-arithmetic.
  4020 
  4021 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4022 allows for selected deletion of wrappers, by introduction of names for
  4023 wrapper functionals.  This implies that addbefore, addSbefore,
  4024 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4025 and that adding two tactics with the same name overwrites the first
  4026 one (emitting a warning).
  4027   type wrapper = (int -> tactic) -> (int -> tactic)
  4028   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4029   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4030   delWrapper, delSWrapper: claset *  string            -> claset
  4031   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4032 
  4033 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4034 semantics; addbefore now affects only the unsafe part of step_tac
  4035 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4036 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4037 by Force_tac;
  4038 
  4039 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4040 compWrapper; added safe wrapper (and access functions for it);
  4041 
  4042 * HOL/split_all_tac is now much faster and fails if there is nothing
  4043 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4044 and the names of the automatically generated variables have changed.
  4045 split_all_tac has moved within claset() from unsafe wrappers to safe
  4046 wrappers, which means that !!-bound variables are split much more
  4047 aggressively, and safe_tac and clarify_tac now split such variables.
  4048 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4049 Note: the same holds for record_split_tac, which does the job of
  4050 split_all_tac for record fields.
  4051 
  4052 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4053 permanently to the default simpset using Addsplits just like
  4054 Addsimps. They can be removed via Delsplits just like
  4055 Delsimps. Lower-case versions are also available.
  4056 
  4057 * HOL/Simplifier: The rule split_if is now part of the default
  4058 simpset. This means that the simplifier will eliminate all occurrences
  4059 of if-then-else in the conclusion of a goal. To prevent this, you can
  4060 either remove split_if completely from the default simpset by
  4061 `Delsplits [split_if]' or remove it in a specific call of the
  4062 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4063 other case splitting rules to/from the default simpset: every datatype
  4064 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4065 t is the name of the datatype).
  4066 
  4067 * Classical reasoner / Simplifier combination: new force_tac (and
  4068 derivatives Force_tac, force) combines rewriting and classical
  4069 reasoning (and whatever other tools) similarly to auto_tac, but is
  4070 aimed to solve the given subgoal completely.
  4071 
  4072 
  4073 *** General ***
  4074 
  4075 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4076 and `goalw': the theory is no longer needed as an explicit argument -
  4077 the current theory context is used; assumptions are no longer returned
  4078 at the ML-level unless one of them starts with ==> or !!; it is
  4079 recommended to convert to these new commands using isatool fixgoal
  4080 (backup your sources first!);
  4081 
  4082 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4083 the current theory context, and 'theory' to lookup stored theories;
  4084 
  4085 * new theory section 'locale' for declaring constants, assumptions and
  4086 definitions that have local scope;
  4087 
  4088 * new theory section 'nonterminals' for purely syntactic types;
  4089 
  4090 * new theory section 'setup' for generic ML setup functions
  4091 (e.g. package initialization);
  4092 
  4093 * the distribution now includes Isabelle icons: see
  4094 lib/logo/isabelle-{small,tiny}.xpm;
  4095 
  4096 * isatool install - install binaries with absolute references to
  4097 ISABELLE_HOME/bin;
  4098 
  4099 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4100 
  4101 * print mode 'emacs' reserved for Isamode;
  4102 
  4103 * support multiple print (ast) translations per constant name;
  4104 
  4105 * theorems involving oracles are now printed with a suffixed [!];
  4106 
  4107 
  4108 *** HOL ***
  4109 
  4110 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4111 
  4112 * HOL/inductive package reorganized and improved: now supports mutual
  4113 definitions such as
  4114 
  4115   inductive EVEN ODD
  4116     intrs
  4117       null "0 : EVEN"
  4118       oddI "n : EVEN ==> Suc n : ODD"
  4119       evenI "n : ODD ==> Suc n : EVEN"
  4120 
  4121 new theorem list "elims" contains an elimination rule for each of the
  4122 recursive sets; inductive definitions now handle disjunctive premises
  4123 correctly (also ZF);
  4124 
  4125 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4126 "mutual_induct" no longer exists - the induction rule is always
  4127 contained in "induct";
  4128 
  4129 
  4130 * HOL/datatype package re-implemented and greatly improved: now
  4131 supports mutually recursive datatypes such as
  4132 
  4133   datatype
  4134     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4135             | SUM ('a aexp) ('a aexp)
  4136             | DIFF ('a aexp) ('a aexp)
  4137             | NUM 'a
  4138   and
  4139     'a bexp = LESS ('a aexp) ('a aexp)
  4140             | AND ('a bexp) ('a bexp)
  4141             | OR ('a bexp) ('a bexp)
  4142 
  4143 as well as indirectly recursive datatypes such as
  4144 
  4145   datatype
  4146     ('a, 'b) term = Var 'a
  4147                   | App 'b ((('a, 'b) term) list)
  4148 
  4149 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4150 induction on mutually / indirectly recursive datatypes.
  4151 
  4152 Primrec equations are now stored in theory and can be accessed via
  4153 <function_name>.simps.
  4154 
  4155 INCOMPATIBILITIES:
  4156 
  4157   - Theories using datatypes must now have theory Datatype as an
  4158     ancestor.
  4159   - The specific <typename>.induct_tac no longer exists - use the
  4160     generic induct_tac instead.
  4161   - natE has been renamed to nat.exhaust - use exhaust_tac
  4162     instead of res_inst_tac ... natE. Note that the variable
  4163     names in nat.exhaust differ from the names in natE, this
  4164     may cause some "fragile" proofs to fail.
  4165   - The theorems split_<typename>_case and split_<typename>_case_asm
  4166     have been renamed to <typename>.split and <typename>.split_asm.
  4167   - Since default sorts of type variables are now handled correctly,
  4168     some datatype definitions may have to be annotated with explicit
  4169     sort constraints.
  4170   - Primrec definitions no longer require function name and type
  4171     of recursive argument.
  4172 
  4173 Consider using isatool fixdatatype to adapt your theories and proof
  4174 scripts to the new package (backup your sources first!).
  4175 
  4176 
  4177 * HOL/record package: considerably improved implementation; now
  4178 includes concrete syntax for record types, terms, updates; theorems
  4179 for surjective pairing and splitting !!-bound record variables; proof
  4180 support is as follows:
  4181 
  4182   1) standard conversions (selectors or updates applied to record
  4183 constructor terms) are part of the standard simpset;
  4184 
  4185   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4186 made part of standard simpset and claset via addIffs;
  4187 
  4188   3) a tactic for record field splitting (record_split_tac) is part of
  4189 the standard claset (addSWrapper);
  4190 
  4191 To get a better idea about these rules you may retrieve them via
  4192 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4193 the name of your record type.
  4194 
  4195 The split tactic 3) conceptually simplifies by the following rule:
  4196 
  4197   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4198 
  4199 Thus any record variable that is bound by meta-all will automatically
  4200 blow up into some record constructor term, consequently the
  4201 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4202 solve record problems automatically.
  4203 
  4204 
  4205 * reorganized the main HOL image: HOL/Integ and String loaded by
  4206 default; theory Main includes everything;
  4207 
  4208 * automatic simplification of integer sums and comparisons, using cancellation;
  4209 
  4210 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4211 
  4212 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4213 
  4214 * many new identities for unions, intersections, set difference, etc.;
  4215 
  4216 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4217 called split_if, split_split, split_sum_case and split_nat_case (to go
  4218 with add/delsplits);
  4219 
  4220 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4221 (?x::unit) = (); this is made part of the default simpset, which COULD
  4222 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4223 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4224 unit_abs_eta_conv is added in order to counter the effect of
  4225 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4226 %u.f();
  4227 
  4228 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4229 makes more sense);
  4230 
  4231 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4232   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4233   disjointness reasoning but breaking a few old proofs.
  4234 
  4235 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4236 to 'converse' from 'inverse' (for compatibility with ZF and some
  4237 literature);
  4238 
  4239 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4240 the well-founded relation;
  4241 
  4242 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4243     Compl A.  The "Compl" syntax remains available as input syntax for this
  4244     release ONLY.
  4245 
  4246 * HOL/Update: new theory of function updates:
  4247     f(a:=b) == %x. if x=a then b else f x
  4248 may also be iterated as in f(a:=b,c:=d,...);
  4249 
  4250 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4251 
  4252 * HOL/List:
  4253   - new function list_update written xs[i:=v] that updates the i-th
  4254     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4255   - new function `upt' written [i..j(] which generates the list
  4256     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4257     bound write [i..j], which is a shorthand for [i..j+1(].
  4258   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4259 
  4260 * HOL/Arith:
  4261   - removed 'pred' (predecessor) function;
  4262   - generalized some theorems about n-1;
  4263   - many new laws about "div" and "mod";
  4264   - new laws about greatest common divisors (see theory ex/Primes);
  4265 
  4266 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4267 instead of "inverse";
  4268 
  4269 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4270   of the multiset ordering;
  4271 
  4272 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4273   (not included by default);
  4274 
  4275 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4276 
  4277 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4278   programs, i.e. different program variables may have different types.
  4279 
  4280 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4281   [previously, this check worked only if the rewrite rule was unconditional]
  4282   Now rew can involve either definitions or equalities (either == or =).
  4283 
  4284 
  4285 *** ZF ***
  4286 
  4287 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4288   only the theorems proved on ZF.ML;
  4289 
  4290 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4291   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4292   disjointness reasoning but breaking a few old proofs.
  4293 
  4294 * ZF/Update: new theory of function updates
  4295     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4296   may also be iterated as in f(a:=b,c:=d,...);
  4297 
  4298 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4299 
  4300 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4301   [previously, this check worked only if the rewrite rule was unconditional]
  4302   Now rew can involve either definitions or equalities (either == or =).
  4303 
  4304 * case_tac provided for compatibility with HOL
  4305     (like the old excluded_middle_tac, but with subgoals swapped)
  4306 
  4307 
  4308 *** Internal programming interfaces ***
  4309 
  4310 * Pure: several new basic modules made available for general use, see
  4311 also src/Pure/README;
  4312 
  4313 * improved the theory data mechanism to support encapsulation (data
  4314 kind name replaced by private Object.kind, acting as authorization
  4315 key); new type-safe user interface via functor TheoryDataFun; generic
  4316 print_data function becomes basically useless;
  4317 
  4318 * removed global_names compatibility flag -- all theory declarations
  4319 are qualified by default;
  4320 
  4321 * module Pure/Syntax now offers quote / antiquote translation
  4322 functions (useful for Hoare logic etc. with implicit dependencies);
  4323 see HOL/ex/Antiquote for an example use;
  4324 
  4325 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4326 cterm -> thm;
  4327 
  4328 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4329 subgoal;
  4330 
  4331 * Display.print_goals function moved to Locale.print_goals;
  4332 
  4333 * standard print function for goals supports current_goals_markers
  4334 variable for marking begin of proof, end of proof, start of goal; the
  4335 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4336 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4337 for example;
  4338 
  4339 
  4340 
  4341 New in Isabelle98 (January 1998)
  4342 --------------------------------
  4343 
  4344 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4345 
  4346 * changed lexical syntax of terms / types: dots made part of long
  4347 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4348 
  4349 * simpset (and claset) reference variable replaced by functions
  4350 simpset / simpset_ref;
  4351 
  4352 * no longer supports theory aliases (via merge) and non-trivial
  4353 implicit merge of thms' signatures;
  4354 
  4355 * most internal names of constants changed due to qualified names;
  4356 
  4357 * changed Pure/Sequence interface (see Pure/seq.ML);
  4358 
  4359 
  4360 *** General Changes ***
  4361 
  4362 * hierachically structured name spaces (for consts, types, axms, thms
  4363 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4364 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4365 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4366 long_names for fully qualified output names; NOTE: ML programs
  4367 (special tactics, packages etc.) referring to internal names may have
  4368 to be adapted to cope with fully qualified names; in case of severe
  4369 backward campatibility problems try setting 'global_names' at compile
  4370 time to have enrything declared within a flat name space; one may also
  4371 fine tune name declarations in theories via the 'global' and 'local'
  4372 section;
  4373 
  4374 * reimplemented the implicit simpset and claset using the new anytype
  4375 data filed in signatures; references simpset:simpset ref etc. are
  4376 replaced by functions simpset:unit->simpset and
  4377 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4378 to patch your ML files accordingly;
  4379 
  4380 * HTML output now includes theory graph data for display with Java
  4381 applet or isatool browser; data generated automatically via isatool
  4382 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4383 
  4384 * defs may now be conditional; improved rewrite_goals_tac to handle
  4385 conditional equations;
  4386 
  4387 * defs now admits additional type arguments, using TYPE('a) syntax;
  4388 
  4389 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4390 creates a new theory node; implicit merge of thms' signatures is
  4391 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4392 transfer:theory->thm->thm in (rare) cases;
  4393 
  4394 * improved handling of draft signatures / theories; draft thms (and
  4395 ctyps, cterms) are automatically promoted to real ones;
  4396 
  4397 * slightly changed interfaces for oracles: admit many per theory, named
  4398 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4399 
  4400 * print_goals: optional output of const types (set show_consts and
  4401 show_types);
  4402 
  4403 * improved output of warnings (###) and errors (***);
  4404 
  4405 * subgoal_tac displays a warning if the new subgoal has type variables;
  4406 
  4407 * removed old README and Makefiles;
  4408 
  4409 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4410 
  4411 * removed obsolete init_pps and init_database;
  4412 
  4413 * deleted the obsolete tactical STATE, which was declared by
  4414     fun STATE tacfun st = tacfun st st;
  4415 
  4416 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4417 (which abbreviates $HOME);
  4418 
  4419 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4420 use isatool fixseq to adapt your ML programs (this works for fully
  4421 qualified references to the Sequence structure only!);
  4422 
  4423 * use_thy no longer requires writable current directory; it always
  4424 reloads .ML *and* .thy file, if either one is out of date;
  4425 
  4426 
  4427 *** Classical Reasoner ***
  4428 
  4429 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4430 tactics that use classical reasoning to simplify a subgoal without
  4431 splitting it into several subgoals;
  4432 
  4433 * Safe_tac: like safe_tac but uses the default claset;
  4434 
  4435 
  4436 *** Simplifier ***
  4437 
  4438 * added simplification meta rules:
  4439     (asm_)(full_)simplify: simpset -> thm -> thm;
  4440 
  4441 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4442 logics (again);
  4443 
  4444 * added prems argument to simplification procedures;
  4445 
  4446 * HOL, FOL, ZF: added infix function `addsplits':
  4447   instead of `<simpset> setloop (split_tac <thms>)'
  4448   you can simply write `<simpset> addsplits <thms>'
  4449 
  4450 
  4451 *** Syntax ***
  4452 
  4453 * TYPE('a) syntax for type reflection terms;
  4454 
  4455 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4456 
  4457 * pretty printer: changed order of mixfix annotation preference (again!);
  4458 
  4459 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4460 
  4461 
  4462 *** HOL ***
  4463 
  4464 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4465   with `addloop' of the simplifier to faciliate case splitting in premises.
  4466 
  4467 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4468 
  4469 * HOL/Auth: new protocol proofs including some for the Internet
  4470   protocol TLS;
  4471 
  4472 * HOL/Map: new theory of `maps' a la VDM;
  4473 
  4474 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4475 cancelling out common nat summands from =, <, <= (in)equalities, or
  4476 differences; simplification procedures nat_cancel_factor for
  4477 cancelling common factor from =, <, <= (in)equalities over natural
  4478 sums; nat_cancel contains both kinds of procedures, it is installed by
  4479 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4480 
  4481 * HOL/simplifier: terms of the form
  4482   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4483   are rewritten to
  4484   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4485   and those of the form
  4486   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4487   are rewritten to
  4488   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4489 
  4490 * HOL/datatype
  4491   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4492 
  4493   P(t_case f1 ... fn x) =
  4494      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4495         ...
  4496        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4497      )
  4498 
  4499   and a theorem `split_t_case_asm' of the form
  4500 
  4501   P(t_case f1 ... fn x) =
  4502     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4503         ...
  4504        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4505      )
  4506   which can be added to a simpset via `addsplits'. The existing theorems
  4507   expand_list_case and expand_option_case have been renamed to
  4508   split_list_case and split_option_case.
  4509 
  4510 * HOL/Arithmetic:
  4511   - `pred n' is automatically converted to `n-1'.
  4512     Users are strongly encouraged not to use `pred' any longer,
  4513     because it will disappear altogether at some point.
  4514   - Users are strongly encouraged to write "0 < n" rather than
  4515     "n ~= 0". Theorems and proof tools have been modified towards this
  4516     `standard'.
  4517 
  4518 * HOL/Lists:
  4519   the function "set_of_list" has been renamed "set" (and its theorems too);
  4520   the function "nth" now takes its arguments in the reverse order and
  4521   has acquired the infix notation "!" as in "xs!n".
  4522 
  4523 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4524 
  4525 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4526   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4527 
  4528 * HOL/record: extensible records with schematic structural subtyping
  4529 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4530 still lacks various theorems and concrete record syntax;
  4531 
  4532 
  4533 *** HOLCF ***
  4534 
  4535 * removed "axioms" and "generated by" sections;
  4536 
  4537 * replaced "ops" section by extended "consts" section, which is capable of
  4538   handling the continuous function space "->" directly;
  4539 
  4540 * domain package:
  4541   . proves theorems immediately and stores them in the theory,
  4542   . creates hierachical name space,
  4543   . now uses normal mixfix annotations (instead of cinfix...),
  4544   . minor changes to some names and values (for consistency),
  4545   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4546   . separator between mutual domain defs: changed "," to "and",
  4547   . improved handling of sort constraints;  now they have to
  4548     appear on the left-hand side of the equations only;
  4549 
  4550 * fixed LAM <x,y,zs>.b syntax;
  4551 
  4552 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4553 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4554 
  4555 
  4556 *** FOL and ZF ***
  4557 
  4558 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4559   with `addloop' of the simplifier to faciliate case splitting in premises.
  4560 
  4561 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4562 in HOL, they strip ALL and --> from proved theorems;
  4563 
  4564 
  4565 
  4566 New in Isabelle94-8 (May 1997)
  4567 ------------------------------
  4568 
  4569 *** General Changes ***
  4570 
  4571 * new utilities to build / run / maintain Isabelle etc. (in parts
  4572 still somewhat experimental); old Makefiles etc. still functional;
  4573 
  4574 * new 'Isabelle System Manual';
  4575 
  4576 * INSTALL text, together with ./configure and ./build scripts;
  4577 
  4578 * reimplemented type inference for greater efficiency, better error
  4579 messages and clean internal interface;
  4580 
  4581 * prlim command for dealing with lots of subgoals (an easier way of
  4582 setting goals_limit);
  4583 
  4584 
  4585 *** Syntax ***
  4586 
  4587 * supports alternative (named) syntax tables (parser and pretty
  4588 printer); internal interface is provided by add_modesyntax(_i);
  4589 
  4590 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4591 be used in conjunction with the Isabelle symbol font; uses the
  4592 "symbols" syntax table;
  4593 
  4594 * added token_translation interface (may translate name tokens in
  4595 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4596 the current print_mode); IMPORTANT: user print translation functions
  4597 are responsible for marking newly introduced bounds
  4598 (Syntax.mark_boundT);
  4599 
  4600 * token translations for modes "xterm" and "xterm_color" that display
  4601 names in bold, underline etc. or colors (which requires a color
  4602 version of xterm);
  4603 
  4604 * infixes may now be declared with names independent of their syntax;
  4605 
  4606 * added typed_print_translation (like print_translation, but may
  4607 access type of constant);
  4608 
  4609 
  4610 *** Classical Reasoner ***
  4611 
  4612 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4613 some limitations.  Blast_tac...
  4614   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4615   + ignores elimination rules that don't have the correct format
  4616         (the conclusion MUST be a formula variable)
  4617   + ignores types, which can make HOL proofs fail
  4618   + rules must not require higher-order unification, e.g. apply_type in ZF
  4619     [message "Function Var's argument not a bound variable" relates to this]
  4620   + its proof strategy is more general but can actually be slower
  4621 
  4622 * substitution with equality assumptions no longer permutes other
  4623 assumptions;
  4624 
  4625 * minor changes in semantics of addafter (now called addaltern); renamed
  4626 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4627 (and access functions for it);
  4628 
  4629 * improved combination of classical reasoner and simplifier:
  4630   + functions for handling clasimpsets
  4631   + improvement of addss: now the simplifier is called _after_ the
  4632     safe steps.
  4633   + safe variant of addss called addSss: uses safe simplifications
  4634     _during_ the safe steps. It is more complete as it allows multiple
  4635     instantiations of unknowns (e.g. with slow_tac).
  4636 
  4637 *** Simplifier ***
  4638 
  4639 * added interface for simplification procedures (functions that
  4640 produce *proven* rewrite rules on the fly, depending on current
  4641 redex);
  4642 
  4643 * ordering on terms as parameter (used for ordered rewriting);
  4644 
  4645 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4646 
  4647 * the solver is now split into a safe and an unsafe part.
  4648 This should be invisible for the normal user, except that the
  4649 functions setsolver and addsolver have been renamed to setSolver and
  4650 addSolver; added safe_asm_full_simp_tac;
  4651 
  4652 
  4653 *** HOL ***
  4654 
  4655 * a generic induction tactic `induct_tac' which works for all datatypes and
  4656 also for type `nat';
  4657 
  4658 * a generic case distinction tactic `exhaust_tac' which works for all
  4659 datatypes and also for type `nat';
  4660 
  4661 * each datatype comes with a function `size';
  4662 
  4663 * patterns in case expressions allow tuple patterns as arguments to
  4664 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4665 
  4666 * primrec now also works with type nat;
  4667 
  4668 * recdef: a new declaration form, allows general recursive functions to be
  4669 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4670 
  4671 * the constant for negation has been renamed from "not" to "Not" to
  4672 harmonize with FOL, ZF, LK, etc.;
  4673 
  4674 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4675 infinite lists;
  4676 
  4677 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4678 
  4679 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4680 problems in commutative rings, using axiomatic type classes for + and *;
  4681 
  4682 * more examples in HOL/MiniML and HOL/Auth;
  4683 
  4684 * more default rewrite rules for quantifiers, union/intersection;
  4685 
  4686 * a new constant `arbitrary == @x.False';
  4687 
  4688 * HOLCF/IOA replaces old HOL/IOA;
  4689 
  4690 * HOLCF changes: derived all rules and arities
  4691   + axiomatic type classes instead of classes
  4692   + typedef instead of faking type definitions
  4693   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4694   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4695   + eliminated the types void, one, tr
  4696   + use unit lift and bool lift (with translations) instead of one and tr
  4697   + eliminated blift from Lift3.thy (use Def instead of blift)
  4698   all eliminated rules are derived as theorems --> no visible changes ;
  4699 
  4700 
  4701 *** ZF ***
  4702 
  4703 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4704 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4705 as ZF_cs addSIs [equalityI];
  4706 
  4707 
  4708 
  4709 New in Isabelle94-7 (November 96)
  4710 ---------------------------------
  4711 
  4712 * allowing negative levels (as offsets) in prlev and choplev;
  4713 
  4714 * super-linear speedup for large simplifications;
  4715 
  4716 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4717 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4718 FAIL); can suppress it using the command Delsimps (ex_simps @
  4719 all_simps); De Morgan laws are also now included, by default;
  4720 
  4721 * improved printing of ==>  :  ~:
  4722 
  4723 * new object-logic "Sequents" adds linear logic, while replacing LK
  4724 and Modal (thanks to Sara Kalvala);
  4725 
  4726 * HOL/Auth: correctness proofs for authentication protocols;
  4727 
  4728 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4729 examples on HOL/Auth);
  4730 
  4731 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4732 the rewriter and classical reasoner simultaneously;
  4733 
  4734 * function uresult no longer returns theorems in "standard" format;
  4735 regain previous version by: val uresult = standard o uresult;
  4736 
  4737 
  4738 
  4739 New in Isabelle94-6
  4740 -------------------
  4741 
  4742 * oracles -- these establish an interface between Isabelle and trusted
  4743 external reasoners, which may deliver results as theorems;
  4744 
  4745 * proof objects (in particular record all uses of oracles);
  4746 
  4747 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4748 
  4749 * "constdefs" section in theory files;
  4750 
  4751 * "primrec" section (HOL) no longer requires names;
  4752 
  4753 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4754 
  4755 
  4756 
  4757 New in Isabelle94-5
  4758 -------------------
  4759 
  4760 * reduced space requirements;
  4761 
  4762 * automatic HTML generation from theories;
  4763 
  4764 * theory files no longer require "..." (quotes) around most types;
  4765 
  4766 * new examples, including two proofs of the Church-Rosser theorem;
  4767 
  4768 * non-curried (1994) version of HOL is no longer distributed;
  4769 
  4770 
  4771 
  4772 New in Isabelle94-4
  4773 -------------------
  4774 
  4775 * greatly reduced space requirements;
  4776 
  4777 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4778 
  4779 * searchable theorem database (see the section "Retrieving theorems" on
  4780 page 8 of the Reference Manual);
  4781 
  4782 * new examples, including Grabczewski's monumental case study of the
  4783 Axiom of Choice;
  4784 
  4785 * The previous version of HOL renamed to Old_HOL;
  4786 
  4787 * The new version of HOL (previously called CHOL) uses a curried syntax
  4788 for functions.  Application looks like f a b instead of f(a,b);
  4789 
  4790 * Mutually recursive inductive definitions finally work in HOL;
  4791 
  4792 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4793 translates to the operator "split";
  4794 
  4795 
  4796 
  4797 New in Isabelle94-3
  4798 -------------------
  4799 
  4800 * new infix operator, addss, allowing the classical reasoner to
  4801 perform simplification at each step of its search.  Example:
  4802         fast_tac (cs addss ss)
  4803 
  4804 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4805 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4806 look like (a,b) instead of <a,b>;
  4807 
  4808 * PLEASE NOTE: CHOL will eventually replace HOL!
  4809 
  4810 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4811 It translates to the operator "split".  A new theory of integers is available;
  4812 
  4813 * In ZF, integer numerals now denote two's-complement binary integers.
  4814 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4815 
  4816 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4817 of the Axiom of Choice;
  4818 
  4819 
  4820 
  4821 New in Isabelle94-2
  4822 -------------------
  4823 
  4824 * Significantly faster resolution;
  4825 
  4826 * the different sections in a .thy file can now be mixed and repeated
  4827 freely;
  4828 
  4829 * Database of theorems for FOL, HOL and ZF.  New
  4830 commands including qed, qed_goal and bind_thm store theorems in the database.
  4831 
  4832 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4833 a given theory (thms_of), or find out what theory a theorem was proved in
  4834 (theory_of_thm);
  4835 
  4836 * Bugs fixed in the inductive definition and datatype packages;
  4837 
  4838 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4839 and HOL_dup_cs obsolete;
  4840 
  4841 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4842 have been removed;
  4843 
  4844 * Simpler definition of function space in ZF;
  4845 
  4846 * new results about cardinal and ordinal arithmetic in ZF;
  4847 
  4848 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4849 types;
  4850 
  4851 
  4852 $Id$