NEWS
author nipkow
Wed Jun 27 11:06:43 2007 +0200 (2007-06-27)
changeset 23509 14a2f87ccc73
parent 23495 e4dd6beeafab
child 23562 6cad6b400cfd
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 resolution prover.
   545   Examples are in the directory MetisExamples.
   546   
   547 * Command "sledgehammer" invokes external automatic theorem provers as background processes.
   548   It generates calls to the "metis" method if successful. These can be pasted into the proof.
   549   Users do not have to wait for the automatic provers to return.
   550 
   551 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   552   is an abbreviation for "of_nat :: nat => int". The simplification rules
   553   for "of_nat" have been changed to work like "int" did previously.
   554   (potential INCOMPATIBILITY)
   555   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   556   - of_nat_diff and of_nat_mult are no longer default simp rules
   557 
   558 * Method "algebra" solves polynomial equations over (semi)rings using
   559   Groebner bases. The (semi)ring structure is defined by locales and
   560   the tool setup depends on that generic context. Installing the
   561   method for a specific type involves instantiating the locale and
   562   possibly adding declarations for computation on the coefficients.
   563   The method is already instantiated for natural numbers and for the
   564   axiomatic class of idoms with numerals.  See also the paper by
   565   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   566   underlying this architecture of context-aware proof-tools.
   567 
   568 * constant "List.op @" now named "List.append".  Use ML antiquotations
   569 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   570 possible incompatibilities when working on ML level.
   571 
   572 * Constant renames due to introduction of canonical name prefixing for
   573   class package:
   574 
   575     HOL.abs ~> HOL.minus_class.abs
   576     HOL.divide ~> HOL.divide_class.divide
   577     Nat.power ~> Nat.power_class.power
   578     Nat.size ~> Nat.size_class.size
   579     Numeral.number_of ~> Numeral.number_class.number_of
   580     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   581 
   582 * Rudimentary class target mechanism involves constant renames:
   583 
   584     Orderings.min ~> Orderings.ord_class.min
   585     Orderings.max ~> Orderings.ord_class.max
   586     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   587 
   588 * case expressions and primrec: missing cases now mapped to "undefined"
   589 instead of "arbitrary"
   590 
   591 * new constant "undefined" with axiom "undefined x = undefined"
   592 
   593 * new class "default" with associated constant "default"
   594 
   595 * new function listsum :: 'a list => 'a for arbitrary monoids.
   596   Special syntax: "SUM x <- xs. f x" (and latex variants)
   597 
   598 * new (input only) syntax for Haskell-like list comprehension, eg
   599   [(x,y). x <- xs, y <- ys, x ~= y]
   600   For details see List.thy.
   601 
   602 * The special syntax for function "filter" has changed from [x : xs. P] to
   603   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   604   and for uniformity. INCOMPATIBILITY
   605 
   606 * New lemma collection field_simps (an extension of ring_simps)
   607   for manipulating (in)equations involving division. Multiplies
   608   with all denominators that can be proved to be non-zero (in equations)
   609   or positive/negative (in inequations).
   610 
   611 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   612   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   613   Removed lemmas field_xyz in Ring_and_Field
   614   because they were subsumed by lemmas xyz.
   615 INCOMPATIBILITY.
   616 
   617 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   618   when generating code.
   619 
   620 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   621   when generating code.
   622 
   623 * Library/Commutative_Ring.thy: switched from recdef to function package;
   624   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   625 
   626 * Some steps towards more uniform lattice theory development in HOL.
   627 
   628     constants "meet" and "join" now named "inf" and "sup"
   629     constant "Meet" now named "Inf"
   630 
   631     classes "meet_semilorder" and "join_semilorder" now named
   632       "lower_semilattice" and "upper_semilattice"
   633     class "lorder" now named "lattice"
   634     class "comp_lat" now named "complete_lattice"
   635 
   636     Instantiation of lattice classes allows explicit definitions
   637     for "inf" and "sup" operations.
   638 
   639   INCOMPATIBILITY.  Theorem renames:
   640 
   641     meet_left_le            ~> inf_le1
   642     meet_right_le           ~> inf_le2
   643     join_left_le            ~> sup_ge1
   644     join_right_le           ~> sup_ge2
   645     meet_join_le            ~> inf_sup_ord
   646     le_meetI                ~> le_infI
   647     join_leI                ~> le_supI
   648     le_meet                 ~> le_inf_iff
   649     le_join                 ~> ge_sup_conv
   650     meet_idempotent         ~> inf_idem
   651     join_idempotent         ~> sup_idem
   652     meet_comm               ~> inf_commute
   653     join_comm               ~> sup_commute
   654     meet_leI1               ~> le_infI1
   655     meet_leI2               ~> le_infI2
   656     le_joinI1               ~> le_supI1
   657     le_joinI2               ~> le_supI2
   658     meet_assoc              ~> inf_assoc
   659     join_assoc              ~> sup_assoc
   660     meet_left_comm          ~> inf_left_commute
   661     meet_left_idempotent    ~> inf_left_idem
   662     join_left_comm          ~> sup_left_commute
   663     join_left_idempotent    ~> sup_left_idem
   664     meet_aci                ~> inf_aci
   665     join_aci                ~> sup_aci
   666     le_def_meet             ~> le_iff_inf
   667     le_def_join             ~> le_iff_sup
   668     join_absorp2            ~> sup_absorb2
   669     join_absorp1            ~> sup_absorb1
   670     meet_absorp1            ~> inf_absorb1
   671     meet_absorp2            ~> inf_absorb2
   672     meet_join_absorp        ~> inf_sup_absorb
   673     join_meet_absorp        ~> sup_inf_absorb
   674     distrib_join_le         ~> distrib_sup_le
   675     distrib_meet_le         ~> distrib_inf_le
   676 
   677     add_meet_distrib_left   ~> add_inf_distrib_left
   678     add_join_distrib_left   ~> add_sup_distrib_left
   679     is_join_neg_meet        ~> is_join_neg_inf
   680     is_meet_neg_join        ~> is_meet_neg_sup
   681     add_meet_distrib_right  ~> add_inf_distrib_right
   682     add_join_distrib_right  ~> add_sup_distrib_right
   683     add_meet_join_distribs  ~> add_sup_inf_distribs
   684     join_eq_neg_meet        ~> sup_eq_neg_inf
   685     meet_eq_neg_join        ~> inf_eq_neg_sup
   686     add_eq_meet_join        ~> add_eq_inf_sup
   687     meet_0_imp_0            ~> inf_0_imp_0
   688     join_0_imp_0            ~> sup_0_imp_0
   689     meet_0_eq_0             ~> inf_0_eq_0
   690     join_0_eq_0             ~> sup_0_eq_0
   691     neg_meet_eq_join        ~> neg_inf_eq_sup
   692     neg_join_eq_meet        ~> neg_sup_eq_inf
   693     join_eq_if              ~> sup_eq_if
   694 
   695     mono_meet               ~> mono_inf
   696     mono_join               ~> mono_sup
   697     meet_bool_eq            ~> inf_bool_eq
   698     join_bool_eq            ~> sup_bool_eq
   699     meet_fun_eq             ~> inf_fun_eq
   700     join_fun_eq             ~> sup_fun_eq
   701     meet_set_eq             ~> inf_set_eq
   702     join_set_eq             ~> sup_set_eq
   703     meet1_iff               ~> inf1_iff
   704     meet2_iff               ~> inf2_iff
   705     meet1I                  ~> inf1I
   706     meet2I                  ~> inf2I
   707     meet1D1                 ~> inf1D1
   708     meet2D1                 ~> inf2D1
   709     meet1D2                 ~> inf1D2
   710     meet2D2                 ~> inf2D2
   711     meet1E                  ~> inf1E
   712     meet2E                  ~> inf2E
   713     join1_iff               ~> sup1_iff
   714     join2_iff               ~> sup2_iff
   715     join1I1                 ~> sup1I1
   716     join2I1                 ~> sup2I1
   717     join1I1                 ~> sup1I1
   718     join2I2                 ~> sup1I2
   719     join1CI                 ~> sup1CI
   720     join2CI                 ~> sup2CI
   721     join1E                  ~> sup1E
   722     join2E                  ~> sup2E
   723 
   724     is_meet_Meet            ~> is_meet_Inf
   725     Meet_bool_def           ~> Inf_bool_def
   726     Meet_fun_def            ~> Inf_fun_def
   727     Meet_greatest           ~> Inf_greatest
   728     Meet_lower              ~> Inf_lower
   729     Meet_set_def            ~> Inf_set_def
   730 
   731     listsp_meetI            ~> listsp_infI
   732     listsp_meet_eq          ~> listsp_inf_eq
   733 
   734     meet_min                ~> inf_min
   735     join_max                ~> sup_max
   736 
   737 * Classes "order" and "linorder": facts "refl", "trans" and
   738 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   739 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   740 
   741 * Classes "order" and "linorder": 
   742 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   743 proofs changed.
   744 
   745 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   746 INCOMPATIBILITY.
   747 
   748 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   749 INCOMPATIBILITY.
   750 
   751 * Added syntactic class "size"; overloaded constant "size" now has
   752 type "'a::size ==> bool"
   753 
   754 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   755 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   756 
   757 * Added method "lexicographic_order" automatically synthesizes
   758 termination relations as lexicographic combinations of size measures
   759 -- 'function' package.
   760 
   761 * HOL/records: generalised field-update to take a function on the
   762 field rather than the new value: r(|A := x|) is translated to A_update
   763 (K x) r The K-combinator that is internally used is called K_record.
   764 INCOMPATIBILITY: Usage of the plain update functions has to be
   765 adapted.
   766  
   767 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   768 0 * x = 0, which are required for a semiring.  Richer structures do
   769 not inherit from semiring_0 anymore, because this property is a
   770 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   771 semiring_0, there is more to prove, but this is mostly trivial.
   772 
   773 * axclass "recpower" was generalized to arbitrary monoids, not just
   774 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   775 commutativity or a semiring property, add the corresponding classes.
   776 
   777 * Unified locale partial_order with class definition (cf. theory
   778 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   779 
   780 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   781 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   782 Isar level, use abbreviations instead.
   783 
   784 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   785 rarely occuring name references (e.g. ``List.op mem.simps'') require
   786 renaming (e.g. ``List.memberl.simps'').
   787 
   788 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   789 INCOMPATIBILITY.
   790 
   791 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   792 
   793 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   794 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   795 significant changes for setting up numeral syntax for types:
   796 
   797   - new constants Numeral.pred and Numeral.succ instead
   798       of former Numeral.bin_pred and Numeral.bin_succ.
   799   - Use integer operations instead of bin_add, bin_mult and so on.
   800   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   801   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   802 
   803 See HOL/Integ/IntArith.thy for an example setup.
   804 
   805 * New top level command 'normal_form' computes the normal form of a
   806 term that may contain free variables. For example ``normal_form
   807 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   808 suitable for heavy-duty computations because the functions are
   809 compiled to ML first.
   810 
   811 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   812 25 like -->); output depends on the "iff" print_mode, the default is
   813 "A = B" (with priority 50).
   814 
   815 * Renamed constants in HOL.thy and Orderings.thy:
   816     op +   ~> HOL.plus_class.plus
   817     op -   ~> HOL.minus_class.minus
   818     uminus ~> HOL.minus_class.uminus
   819     op *   ~> HOL.times_class.times
   820     op <   ~> Orderings.ord_class.less
   821     op <=  ~> Orderings.ord_class.less_eq
   822 
   823 Adaptions may be required in the following cases:
   824 
   825 a) User-defined constants using any of the names "plus", "minus", "times",
   826 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   827 may go wrong.
   828 INCOMPATIBILITY: use more specific names.
   829 
   830 b) Variables named "plus", "minus", "times", "less", "less_eq"
   831 INCOMPATIBILITY: use more specific names.
   832 
   833 c) Permutative equations (e.g. "a + b = b + a")
   834 Since the change of names also changes the order of terms, permutative
   835 rewrite rules may get applied in a different order. Experience shows that
   836 this is rarely the case (only two adaptions in the whole Isabelle
   837 distribution).
   838 INCOMPATIBILITY: rewrite proofs
   839 
   840 d) ML code directly refering to constant names
   841 This in general only affects hand-written proof tactics, simprocs and so on.
   842 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   843 of const_name ML antiquotations.
   844 
   845 * Relations less (<) and less_eq (<=) are also available on type bool.
   846 Modified syntax to disallow nesting without explicit parentheses,
   847 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   848 
   849 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   850 
   851 * Relation composition operator "op O" now has precedence 75 and binds
   852 stronger than union and intersection. INCOMPATIBILITY.
   853 
   854 * The old set interval syntax "{m..n(}" (and relatives) has been
   855 removed.  Use "{m..<n}" (and relatives) instead.
   856 
   857 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   858 "t = s" to False (by simproc "neq_simproc").  For backward
   859 compatibility this can be disabled by ML "reset use_neq_simproc".
   860 
   861 * "m dvd n" where m and n are numbers is evaluated to True/False by
   862 simp.
   863 
   864 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   865 
   866 * Theorem setsum_mult renamed to setsum_right_distrib.
   867 
   868 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   869 ``rule'' method.
   870 
   871 * Reimplemented methods ``sat'' and ``satx'', with several
   872 improvements: goals no longer need to be stated as "<prems> ==>
   873 False", equivalences (i.e. "=" on type bool) are handled, variable
   874 names of the form "lit_<n>" are no longer reserved, significant
   875 speedup.
   876 
   877 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   878 zChaff is still supported as well.
   879 
   880 * 'inductive' and 'datatype': provide projections of mutual rules,
   881 bundled as foo_bar.inducts;
   882 
   883 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   884 Library.
   885 
   886 * Library: moved theory Accessible_Part to main HOL.
   887 
   888 * Library: added theory Coinductive_List of potentially infinite lists
   889 as greatest fixed-point.
   890 
   891 * Library: added theory AssocList which implements (finite) maps as
   892 association lists.
   893 
   894 * Added proof method ``evaluation'' for efficiently solving a goal
   895 (i.e. a boolean expression) by compiling it to ML. The goal is
   896 "proved" (via an oracle) if it evaluates to True.
   897 
   898 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   899 also when invoked by the simplifier.  This results in the simplifier
   900 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   901 fast_arith_split_limit to 0 to obtain the old behavior.
   902 
   903 * Support for hex (0x20) and binary (0b1001) numerals.
   904 
   905 * New method: reify eqs (t), where eqs are equations for an
   906 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   907 parameter, computes a term s::'b and a list xs::'a list and proves the
   908 theorem I xs s = t. This is also known as reification or quoting. The
   909 resulting theorem is applied to the subgoal to substitute t with I xs
   910 s.  If t is omitted, the subgoal itself is reified.
   911 
   912 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   913 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   914 where f is supposed to be a computable function (in the sense of code
   915 generattion). The method uses reify to compute s and xs as above then
   916 applies corr_thm and uses normalization by evaluation to "prove" f s =
   917 r and finally gets the theorem t = r, which is again applied to the
   918 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   919 
   920 * Reflection: Automatic refification now handels binding, an example
   921 is available in HOL/ex/ReflectionEx.thy
   922 
   923 
   924 *** HOL-Algebra ***
   925 
   926 * Formalisation of ideals and the quotient construction over rings.
   927 
   928 * Order and lattice theory no longer based on records.
   929 INCOMPATIBILITY.
   930 
   931 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   932 greatest_closed.  INCOMPATIBILITY.
   933 
   934 * Method algebra is now set up via an attribute.  For examples see
   935 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   936 of algebraic structures.
   937 
   938 * Renamed theory CRing to Ring.
   939 
   940 
   941 *** HOL-Complex ***
   942 
   943 * Theory Real: new method ferrack implements quantifier elimination
   944 for linear arithmetic over the reals. The quantifier elimination
   945 feature is used only for decision, for compatibility with arith. This
   946 means a goal is either solved or left unchanged, no simplification.
   947 
   948 * Hyperreal: Functions root and sqrt are now defined on negative real
   949 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   950 Nonnegativity side conditions have been removed from many lemmas, so
   951 that more subgoals may now be solved by simplification; potential
   952 INCOMPATIBILITY.
   953 
   954 * Real: New axiomatic classes formalize real normed vector spaces and
   955 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   956 and norm :: 'a => real.
   957 
   958 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   959 from reals into other types. The overloaded constant Reals :: 'a set
   960 is now defined as range of_real; potential INCOMPATIBILITY.
   961 
   962 * Real: ML code generation is supported now and hence also quickcheck.
   963 Reals are implemented as arbitrary precision rationals.
   964 
   965 * Hyperreal: Several constants that previously worked only for the
   966 reals have been generalized, so they now work over arbitrary vector
   967 spaces. Type annotations may need to be added in some cases; potential
   968 INCOMPATIBILITY.
   969 
   970   Infinitesimal  :: ('a::real_normed_vector) star set
   971   HFinite        :: ('a::real_normed_vector) star set
   972   HInfinite      :: ('a::real_normed_vector) star set
   973   approx         :: ('a::real_normed_vector) star => 'a star => bool
   974   monad          :: ('a::real_normed_vector) star => 'a star set
   975   galaxy         :: ('a::real_normed_vector) star => 'a star set
   976   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   977   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   978   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   979   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   980   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   981   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   982   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   983   sgn            :: 'a::real_normed_vector => 'a
   984   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   985 
   986 * Complex: Some complex-specific constants are now abbreviations for
   987 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   988 hnorm.  Other constants have been entirely removed in favor of the
   989 polymorphic versions (INCOMPATIBILITY):
   990 
   991   approx        <-- capprox
   992   HFinite       <-- CFinite
   993   HInfinite     <-- CInfinite
   994   Infinitesimal <-- CInfinitesimal
   995   monad         <-- cmonad
   996   galaxy        <-- cgalaxy
   997   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   998   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   999   (ns)deriv     <-- (ns)cderiv
  1000 
  1001 
  1002 *** ML ***
  1003 
  1004 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1005 
  1006 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1007 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1008 init only required for impure data.  INCOMPATIBILITY: empty really
  1009 need to be empty (no dependencies on theory content!)
  1010 
  1011 * ML within Isar: antiquotations allow to embed statically-checked
  1012 formal entities in the source, referring to the context available at
  1013 compile-time.  For example:
  1014 
  1015 ML {* @{typ "'a => 'b"} *}
  1016 ML {* @{term "%x. x"} *}
  1017 ML {* @{prop "x == y"} *}
  1018 ML {* @{ctyp "'a => 'b"} *}
  1019 ML {* @{cterm "%x. x"} *}
  1020 ML {* @{cprop "x == y"} *}
  1021 ML {* @{thm asm_rl} *}
  1022 ML {* @{thms asm_rl} *}
  1023 ML {* @{const_name c} *}
  1024 ML {* @{const_syntax c} *}
  1025 ML {* @{context} *}
  1026 ML {* @{theory} *}
  1027 ML {* @{theory Pure} *}
  1028 ML {* @{simpset} *}
  1029 ML {* @{claset} *}
  1030 ML {* @{clasimpset} *}
  1031 
  1032 The same works for sources being ``used'' within an Isar context.
  1033 
  1034 * ML in Isar: improved error reporting; extra verbosity with
  1035 Toplevel.debug enabled.
  1036 
  1037 * Pure/library:
  1038 
  1039   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1040   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1041 
  1042 The semantics of "burrow" is: "take a function with *simulatanously*
  1043 transforms a list of value, and apply it *simulatanously* to a list of
  1044 list of values of the appropriate type". Compare this with "map" which
  1045 would *not* apply its argument function simulatanously but in
  1046 sequence; "fold_burrow" has an additional context.
  1047 
  1048 * Pure/library: functions map2 and fold2 with curried syntax for
  1049 simultanous mapping and folding:
  1050 
  1051     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1052     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1053 
  1054 * Pure/library: indexed lists - some functions in the Isabelle library
  1055 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1056 given more convenient names and signatures reminiscent of similar
  1057 functions for alists, tables, etc:
  1058 
  1059   val nth: 'a list -> int -> 'a 
  1060   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1061   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1062 
  1063 Note that fold_index starts counting at index 0, not 1 like foldln
  1064 used to.
  1065 
  1066 * Pure/library: added general ``divide_and_conquer'' combinator on
  1067 lists.
  1068 
  1069 * Pure/General/table.ML: the join operations now works via exceptions
  1070 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1071 admits slightly more efficient complex applications.
  1072 
  1073 * Pure: datatype Context.generic joins theory/Proof.context and
  1074 provides some facilities for code that works in either kind of
  1075 context, notably GenericDataFun for uniform theory and proof data.
  1076 
  1077 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1078 use Context.generic instead of just theory.
  1079 
  1080 * Pure: simplified internal attribute type, which is now always
  1081 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1082 vs. local (Proof.context) attributes have been discontinued, while
  1083 minimizing code duplication.  Thm.rule_attribute and
  1084 Thm.declaration_attribute build canonical attributes; see also
  1085 structure Context for further operations on Context.generic, notably
  1086 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1087 declarations and definitions.
  1088 
  1089 * Pure/kernel: consts certification ignores sort constraints given in
  1090 signature declarations.  (This information is not relevant to the
  1091 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1092 potential INCOMPATIBILITY.
  1093 
  1094 * Pure: axiomatic type classes are now purely definitional, with
  1095 explicit proofs of class axioms and super class relations performed
  1096 internally.  See Pure/axclass.ML for the main internal interfaces --
  1097 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1098 AxClass.axiomatize_class/classrel/arity supercede
  1099 Sign.add_classes/classrel/arities.
  1100 
  1101 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1102 global/local versions on theory vs. Proof.context have been
  1103 discontinued; Attrib.syntax and Method.syntax have been adapted
  1104 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1105 attributes, methods, etc.
  1106 
  1107 * Pure: several functions of signature "... -> theory -> theory * ..."
  1108 have been reoriented to "... -> theory -> ... * theory" in order to
  1109 allow natural usage in combination with the ||>, ||>>, |-> and
  1110 fold_map combinators.
  1111 
  1112 * Pure: official theorem names (closed derivations) and additional
  1113 comments (tags) are now strictly separate.  Name hints -- which are
  1114 maintained as tags -- may be attached any time without affecting the
  1115 derivation.
  1116 
  1117 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1118 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1119 achieve the old behaviour.
  1120 
  1121 * Pure: the "Goal" constant is now called "prop", supporting a
  1122 slightly more general idea of ``protecting'' meta-level rule
  1123 statements.
  1124 
  1125 * Pure: Logic.(un)varify only works in a global context, which is now
  1126 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1127 Logic.legacy_(un)varify as temporary workaround.
  1128 
  1129 * Pure: structure Name provides scalable operations for generating
  1130 internal variable names, notably Name.variants etc.  This replaces
  1131 some popular functions from term.ML:
  1132 
  1133   Term.variant		->  Name.variant
  1134   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1135   Term.invent_names	->  Name.invent_list
  1136 
  1137 Note that low-level renaming rarely occurs in new code -- operations
  1138 from structure Variable are used instead (see below).
  1139 
  1140 * Pure: structure Variable provides fundamental operations for proper
  1141 treatment of fixed/schematic variables in a context.  For example,
  1142 Variable.import introduces fixes for schematics of given facts and
  1143 Variable.export reverses the effect (up to renaming) -- this replaces
  1144 various freeze_thaw operations.
  1145 
  1146 * Pure: structure Goal provides simple interfaces for
  1147 init/conclude/finish and tactical prove operations (replacing former
  1148 Tactic.prove).  Goal.prove is the canonical way to prove results
  1149 within a given context; Goal.prove_global is a degraded version for
  1150 theory level goals, including a global Drule.standard.  Note that
  1151 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1152 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1153 in a locale context).
  1154 
  1155 * Isar: simplified treatment of user-level errors, using exception
  1156 ERROR of string uniformly.  Function error now merely raises ERROR,
  1157 without any side effect on output channels.  The Isar toplevel takes
  1158 care of proper display of ERROR exceptions.  ML code may use plain
  1159 handle/can/try; cat_error may be used to concatenate errors like this:
  1160 
  1161   ... handle ERROR msg => cat_error msg "..."
  1162 
  1163 Toplevel ML code (run directly or through the Isar toplevel) may be
  1164 embedded into the Isar toplevel with exception display/debug like
  1165 this:
  1166 
  1167   Isar.toplevel (fn () => ...)
  1168 
  1169 INCOMPATIBILITY, removed special transform_error facilities, removed
  1170 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1171 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1172 -- use plain ERROR instead.
  1173 
  1174 * Isar: theory setup now has type (theory -> theory), instead of a
  1175 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1176 
  1177 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1178 subject to ProofContext.debug/verbose flags.
  1179 
  1180 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1181 theory before entering a proof state.  Transactions now always see a
  1182 quasi-functional intermediate checkpoint, both in interactive and
  1183 batch mode.
  1184 
  1185 * Simplifier: the simpset of a running simplification process now
  1186 contains a proof context (cf. Simplifier.the_context), which is the
  1187 very context that the initial simpset has been retrieved from (by
  1188 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1189 (solver, looper etc.) may depend on arbitrary proof data.
  1190 
  1191 * Simplifier.inherit_context inherits the proof context (plus the
  1192 local bounds) of the current simplification process; any simproc
  1193 etc. that calls the Simplifier recursively should do this!  Removed
  1194 former Simplifier.inherit_bounds, which is already included here --
  1195 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1196 specify an explicit context using Simplifier.context/theory_context.
  1197 
  1198 * Simplifier/Classical Reasoner: more abstract interfaces
  1199 change_simpset/claset for modifying the simpset/claset reference of a
  1200 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1201 INCOMPATIBILITY.
  1202 
  1203 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1204 "Trueprop" etc.
  1205 
  1206 
  1207 *** System ***
  1208 
  1209 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1210 locations -- now includes the Isabelle version identifier as well.
  1211 This simplifies use of multiple Isabelle installations.
  1212 
  1213 * isabelle-process: option -S (secure mode) disables some critical
  1214 operations, notably runtime compilation and evaluation of ML source
  1215 code.
  1216 
  1217 
  1218 New in Isabelle2005 (October 2005)
  1219 ----------------------------------
  1220 
  1221 *** General ***
  1222 
  1223 * Theory headers: the new header syntax for Isar theories is
  1224 
  1225   theory <name>
  1226   imports <theory1> ... <theoryN>
  1227   uses <file1> ... <fileM>
  1228   begin
  1229 
  1230 where the 'uses' part is optional.  The previous syntax
  1231 
  1232   theory <name> = <theory1> + ... + <theoryN>:
  1233 
  1234 will disappear in the next release.  Use isatool fixheaders to convert
  1235 existing theory files.  Note that there is no change in ancient
  1236 non-Isar theories now, but these will disappear soon.
  1237 
  1238 * Theory loader: parent theories can now also be referred to via
  1239 relative and absolute paths.
  1240 
  1241 * Command 'find_theorems' searches for a list of criteria instead of a
  1242 list of constants. Known criteria are: intro, elim, dest, name:string,
  1243 simp:term, and any term. Criteria can be preceded by '-' to select
  1244 theorems that do not match. Intro, elim, dest select theorems that
  1245 match the current goal, name:s selects theorems whose fully qualified
  1246 name contain s, and simp:term selects all simplification rules whose
  1247 lhs match term.  Any other term is interpreted as pattern and selects
  1248 all theorems matching the pattern. Available in ProofGeneral under
  1249 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1250 
  1251   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1252 
  1253 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1254 matching the current goal as introduction rule and not having "HOL."
  1255 in their name (i.e. not being defined in theory HOL).
  1256 
  1257 * Command 'thms_containing' has been discontinued in favour of
  1258 'find_theorems'; INCOMPATIBILITY.
  1259 
  1260 * Communication with Proof General is now 8bit clean, which means that
  1261 Unicode text in UTF-8 encoding may be used within theory texts (both
  1262 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1263 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1264 
  1265   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1266   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1267 
  1268 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1269 Classical Reasoner.  Typical big applications run around 2 times
  1270 faster.
  1271 
  1272 
  1273 *** Document preparation ***
  1274 
  1275 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1276 of raw sources.  Only those symbols that do not require additional
  1277 LaTeX packages (depending on comments in isabellesym.sty) are
  1278 displayed properly, everything else is left verbatim.  isatool display
  1279 and isatool print are used as front ends (these are subject to the
  1280 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1281 
  1282 * Command tags control specific markup of certain regions of text,
  1283 notably folding and hiding.  Predefined tags include "theory" (for
  1284 theory begin and end), "proof" for proof commands, and "ML" for
  1285 commands involving ML code; the additional tags "visible" and
  1286 "invisible" are unused by default.  Users may give explicit tag
  1287 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1288 interpretation of tags is determined by the LaTeX job during document
  1289 preparation: see option -V of isatool usedir, or options -n and -t of
  1290 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1291 \isadroptag.
  1292 
  1293 Several document versions may be produced at the same time via isatool
  1294 usedir (the generated index.html will link all of them).  Typical
  1295 specifications include ''-V document=theory,proof,ML'' to present
  1296 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1297 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1298 these parts without any formal replacement text.  The Isabelle site
  1299 default settings produce ''document'' and ''outline'' versions as
  1300 specified above.
  1301 
  1302 * Several new antiquotations:
  1303 
  1304   @{term_type term} prints a term with its type annotated;
  1305 
  1306   @{typeof term} prints the type of a term;
  1307 
  1308   @{const const} is the same as @{term const}, but checks that the
  1309   argument is a known logical constant;
  1310 
  1311   @{term_style style term} and @{thm_style style thm} print a term or
  1312   theorem applying a "style" to it
  1313 
  1314   @{ML text}
  1315 
  1316 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1317 definitions, equations, inequations etc., 'concl' printing only the
  1318 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1319 to print the specified premise.  TermStyle.add_style provides an ML
  1320 interface for introducing further styles.  See also the "LaTeX Sugar"
  1321 document practical applications.  The ML antiquotation prints
  1322 type-checked ML expressions verbatim.
  1323 
  1324 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1325 and 'text' support optional locale specification '(in loc)', which
  1326 specifies the default context for interpreting antiquotations.  For
  1327 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1328 
  1329 * Option 'locale=NAME' of antiquotations specifies an alternative
  1330 context interpreting the subsequent argument.  For example: @{thm
  1331 [locale=lattice] inf_assoc}.
  1332 
  1333 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1334 a proof context.
  1335 
  1336 * Proper output of antiquotations for theory commands involving a
  1337 proof context (such as 'locale' or 'theorem (in loc) ...').
  1338 
  1339 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1340 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1341 
  1342 * isatool usedir: new option -C (default true) controls whether option
  1343 -D should include a copy of the original document directory; -C false
  1344 prevents unwanted effects such as copying of administrative CVS data.
  1345 
  1346 
  1347 *** Pure ***
  1348 
  1349 * Considerably improved version of 'constdefs' command.  Now performs
  1350 automatic type-inference of declared constants; additional support for
  1351 local structure declarations (cf. locales and HOL records), see also
  1352 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1353 sequential dependencies of definitions within a single 'constdefs'
  1354 section; moreover, the declared name needs to be an identifier.  If
  1355 all fails, consider to fall back on 'consts' and 'defs' separately.
  1356 
  1357 * Improved indexed syntax and implicit structures.  First of all,
  1358 indexed syntax provides a notational device for subscripted
  1359 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1360 expressions.  Secondly, in a local context with structure
  1361 declarations, number indexes \<^sub>n or the empty index (default
  1362 number 1) refer to a certain fixed variable implicitly; option
  1363 show_structs controls printing of implicit structures.  Typical
  1364 applications of these concepts involve record types and locales.
  1365 
  1366 * New command 'no_syntax' removes grammar declarations (and
  1367 translations) resulting from the given syntax specification, which is
  1368 interpreted in the same manner as for the 'syntax' command.
  1369 
  1370 * 'Advanced' translation functions (parse_translation etc.) may depend
  1371 on the signature of the theory context being presently used for
  1372 parsing/printing, see also isar-ref manual.
  1373 
  1374 * Improved 'oracle' command provides a type-safe interface to turn an
  1375 ML expression of type theory -> T -> term into a primitive rule of
  1376 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1377 is already included here); see also FOL/ex/IffExample.thy;
  1378 INCOMPATIBILITY.
  1379 
  1380 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1381 before); "cI" is no longer bound, use "c.intro" instead.
  1382 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1383 axclasses vs. locales.
  1384 
  1385 * Improved internal renaming of symbolic identifiers -- attach primes
  1386 instead of base 26 numbers.
  1387 
  1388 * New flag show_question_marks controls printing of leading question
  1389 marks in schematic variable names.
  1390 
  1391 * In schematic variable names, *any* symbol following \<^isub> or
  1392 \<^isup> is now treated as part of the base name.  For example, the
  1393 following works without printing of awkward ".0" indexes:
  1394 
  1395   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1396     by simp
  1397 
  1398 * Inner syntax includes (*(*nested*) comments*).
  1399 
  1400 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1401 annotations as "(00...)".
  1402 
  1403 * Clear separation of logical types and nonterminals, where the latter
  1404 may only occur in 'syntax' specifications or type abbreviations.
  1405 Before that distinction was only partially implemented via type class
  1406 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1407 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1408 exotic syntax specifications may require further adaption
  1409 (e.g. Cube/Cube.thy).
  1410 
  1411 * Removed obsolete type class "logic", use the top sort {} instead.
  1412 Note that non-logical types should be declared as 'nonterminals'
  1413 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1414 specifications.
  1415 
  1416 * Attributes 'induct' and 'cases': type or set names may now be
  1417 locally fixed variables as well.
  1418 
  1419 * Simplifier: can now control the depth to which conditional rewriting
  1420 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1421 Limit.
  1422 
  1423 * Simplifier: simplification procedures may now take the current
  1424 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1425 interface), which is very useful for calling the Simplifier
  1426 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1427 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1428 low-level mk_simproc no longer applies Logic.varify internally, to
  1429 allow for use in a context of fixed variables.
  1430 
  1431 * thin_tac now works even if the assumption being deleted contains !!
  1432 or ==>.  More generally, erule now works even if the major premise of
  1433 the elimination rule contains !! or ==>.
  1434 
  1435 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1436 
  1437 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1438 from Pure, which contains all common declarations already.  Both
  1439 theories are defined via plain Isabelle/Isar .thy files.
  1440 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1441 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1442 use isatool fixcpure to adapt your theory and ML sources.
  1443 
  1444 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1445 selections of theorems in named facts via index ranges.
  1446 
  1447 * 'print_theorems': in theory mode, really print the difference
  1448 wrt. the last state (works for interactive theory development only),
  1449 in proof mode print all local facts (cf. 'print_facts');
  1450 
  1451 * 'hide': option '(open)' hides only base names.
  1452 
  1453 * More efficient treatment of intermediate checkpoints in interactive
  1454 theory development.
  1455 
  1456 * Code generator is now invoked via code_module (incremental code
  1457 generation) and code_library (modular code generation, ML structures
  1458 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1459 must be quoted when used as identifiers.
  1460 
  1461 * New 'value' command for reading, evaluating and printing terms using
  1462 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1463 quoted when used as identifier.
  1464 
  1465 
  1466 *** Locales ***
  1467 
  1468 * New commands for the interpretation of locale expressions in
  1469 theories (1), locales (2) and proof contexts (3).  These generate
  1470 proof obligations from the expression specification.  After the
  1471 obligations have been discharged, theorems of the expression are added
  1472 to the theory, target locale or proof context.  The synopsis of the
  1473 commands is a follows:
  1474 
  1475   (1) interpretation expr inst
  1476   (2) interpretation target < expr
  1477   (3) interpret expr inst
  1478 
  1479 Interpretation in theories and proof contexts require a parameter
  1480 instantiation of terms from the current context.  This is applied to
  1481 specifications and theorems of the interpreted expression.
  1482 Interpretation in locales only permits parameter renaming through the
  1483 locale expression.  Interpretation is smart in that interpretations
  1484 that are active already do not occur in proof obligations, neither are
  1485 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1486 inspect active interpretations of a particular locale.  For details,
  1487 see the Isar Reference manual.  Examples can be found in
  1488 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1489 
  1490 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1491 'interpret' instead.
  1492 
  1493 * New context element 'constrains' for adding type constraints to
  1494 parameters.
  1495 
  1496 * Context expressions: renaming of parameters with syntax
  1497 redeclaration.
  1498 
  1499 * Locale declaration: 'includes' disallowed.
  1500 
  1501 * Proper static binding of attribute syntax -- i.e. types / terms /
  1502 facts mentioned as arguments are always those of the locale definition
  1503 context, independently of the context of later invocations.  Moreover,
  1504 locale operations (renaming and type / term instantiation) are applied
  1505 to attribute arguments as expected.
  1506 
  1507 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1508 actual attributes; rare situations may require Attrib.attribute to
  1509 embed those attributes into Attrib.src that lack concrete syntax.
  1510 Attribute implementations need to cooperate properly with the static
  1511 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1512 Attrib.XXX_thm etc. already do the right thing without further
  1513 intervention.  Only unusual applications -- such as "where" or "of"
  1514 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1515 on the context and the facts involved -- may have to assign parsed
  1516 values to argument tokens explicitly.
  1517 
  1518 * Changed parameter management in theorem generation for long goal
  1519 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1520 theorem statement in rare situations.
  1521 
  1522 * Locale inspection command 'print_locale' omits notes elements.  Use
  1523 'print_locale!' to have them included in the output.
  1524 
  1525 
  1526 *** Provers ***
  1527 
  1528 * Provers/hypsubst.ML: improved version of the subst method, for
  1529 single-step rewriting: it now works in bound variable contexts. New is
  1530 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1531 rewrite a different subterm than the original subst method, which is
  1532 still available as 'simplesubst'.
  1533 
  1534 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1535 and quasi orders.
  1536 
  1537 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1538 reflexive-transitive closure of relations.
  1539 
  1540 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1541 limit (previously hard-coded with a value of 20) user-definable.
  1542 
  1543 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1544 is peformed already.  Object-logics merely need to finish their
  1545 initial simpset configuration as before.  INCOMPATIBILITY.
  1546 
  1547 
  1548 *** HOL ***
  1549 
  1550 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1551 
  1552   syntax (epsilon)
  1553     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1554 
  1555 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1556 and x-symbol; use option '-m epsilon' to get it actually printed.
  1557 Moreover, the mathematically important symbolic identifier \<epsilon>
  1558 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1559 
  1560 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1561 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1562 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1563 support corresponding Isar calculations.
  1564 
  1565 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1566 instead of ":".
  1567 
  1568 * theory SetInterval: changed the syntax for open intervals:
  1569 
  1570   Old       New
  1571   {..n(}    {..<n}
  1572   {)n..}    {n<..}
  1573   {m..n(}   {m..<n}
  1574   {)m..n}   {m<..n}
  1575   {)m..n(}  {m<..<n}
  1576 
  1577 The old syntax is still supported but will disappear in the next
  1578 release.  For conversion use the following Emacs search and replace
  1579 patterns (these are not perfect but work quite well):
  1580 
  1581   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1582   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1583 
  1584 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1585 equalities in commutative rings; method 'algebra' provides a generic
  1586 interface.
  1587 
  1588 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1589 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1590 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1591 be a tuple pattern.
  1592 
  1593 Some new syntax forms are available:
  1594 
  1595   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1596   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1597   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1598   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1599 
  1600 The latter form "\<Sum>x < k. e" used to be based on a separate
  1601 function "Summation", which has been discontinued.
  1602 
  1603 * theory Finite_Set: in structured induction proofs, the insert case
  1604 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1605 (insert F x)'.
  1606 
  1607 * The 'refute' command has been extended to support a much larger
  1608 fragment of HOL, including axiomatic type classes, constdefs and
  1609 typedefs, inductive datatypes and recursion.
  1610 
  1611 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1612 Requires zChaff with proof generation to be installed.  See
  1613 HOL/ex/SAT_Examples.thy for examples.
  1614 
  1615 * Datatype induction via method 'induct' now preserves the name of the
  1616 induction variable. For example, when proving P(xs::'a list) by
  1617 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1618 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1619 in unstructured proof scripts.
  1620 
  1621 * Reworked implementation of records.  Improved scalability for
  1622 records with many fields, avoiding performance problems for type
  1623 inference. Records are no longer composed of nested field types, but
  1624 of nested extension types. Therefore the record type only grows linear
  1625 in the number of extensions and not in the number of fields.  The
  1626 top-level (users) view on records is preserved.  Potential
  1627 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1628 old record representation. The type generated for a record is called
  1629 <record_name>_ext_type.
  1630 
  1631 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1632 proofs triggered by a record definition or a simproc (if
  1633 quick_and_dirty is enabled).  Definitions of large records can take
  1634 quite long.
  1635 
  1636 New simproc record_upd_simproc for simplification of multiple record
  1637 updates enabled by default.  Moreover, trivial updates are also
  1638 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1639 occasionally, since simplification is more powerful by default.
  1640 
  1641 * typedef: proper support for polymorphic sets, which contain extra
  1642 type-variables in the term.
  1643 
  1644 * Simplifier: automatically reasons about transitivity chains
  1645 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1646 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1647 old proofs break occasionally as simplification may now solve more
  1648 goals than previously.
  1649 
  1650 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1651 present.  Works for all partial orders (class "order"), in particular
  1652 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1653 just like y <= x.
  1654 
  1655 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1656 bound variable or a constant then the let is unfolded.  Otherwise
  1657 first a is simplified to b, and then f b is simplified to g. If
  1658 possible we abstract b from g arriving at "let x = b in h x",
  1659 otherwise we unfold the let and arrive at g.  The simproc can be
  1660 enabled/disabled by the reference use_let_simproc.  Potential
  1661 INCOMPATIBILITY since simplification is more powerful by default.
  1662 
  1663 * Classical reasoning: the meson method now accepts theorems as arguments.
  1664 
  1665 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1666 jobs to provide advice on the provability of subgoals.
  1667 
  1668 * Theory OrderedGroup and Ring_and_Field: various additions and
  1669 improvements to faciliate calculations involving equalities and
  1670 inequalities.
  1671 
  1672 The following theorems have been eliminated or modified
  1673 (INCOMPATIBILITY):
  1674 
  1675   abs_eq             now named abs_of_nonneg
  1676   abs_of_ge_0        now named abs_of_nonneg
  1677   abs_minus_eq       now named abs_of_nonpos
  1678   imp_abs_id         now named abs_of_nonneg
  1679   imp_abs_neg_id     now named abs_of_nonpos
  1680   mult_pos           now named mult_pos_pos
  1681   mult_pos_le        now named mult_nonneg_nonneg
  1682   mult_pos_neg_le    now named mult_nonneg_nonpos
  1683   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1684   mult_neg           now named mult_neg_neg
  1685   mult_neg_le        now named mult_nonpos_nonpos
  1686 
  1687 * The following lemmas in Ring_and_Field have been added to the simplifier:
  1688      
  1689      zero_le_square
  1690      not_square_less_zero 
  1691 
  1692   The following lemmas have been deleted from Real/RealPow:
  1693   
  1694      realpow_zero_zero
  1695      realpow_two
  1696      realpow_less
  1697      zero_le_power
  1698      realpow_two_le
  1699      abs_realpow_two
  1700      realpow_two_abs     
  1701 
  1702 * Theory Parity: added rules for simplifying exponents.
  1703 
  1704 * Theory List:
  1705 
  1706 The following theorems have been eliminated or modified
  1707 (INCOMPATIBILITY):
  1708 
  1709   list_all_Nil       now named list_all.simps(1)
  1710   list_all_Cons      now named list_all.simps(2)
  1711   list_all_conv      now named list_all_iff
  1712   set_mem_eq         now named mem_iff
  1713 
  1714 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1715 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1716 
  1717 
  1718 *** HOL-Complex ***
  1719 
  1720 * Theory RealDef: better support for embedding natural numbers and
  1721 integers in the reals.
  1722 
  1723 The following theorems have been eliminated or modified
  1724 (INCOMPATIBILITY):
  1725 
  1726   exp_ge_add_one_self  now requires no hypotheses
  1727   real_of_int_add      reversed direction of equality (use [symmetric])
  1728   real_of_int_minus    reversed direction of equality (use [symmetric])
  1729   real_of_int_diff     reversed direction of equality (use [symmetric])
  1730   real_of_int_mult     reversed direction of equality (use [symmetric])
  1731 
  1732 * Theory RComplete: expanded support for floor and ceiling functions.
  1733 
  1734 * Theory Ln is new, with properties of the natural logarithm
  1735 
  1736 * Hyperreal: There is a new type constructor "star" for making
  1737 nonstandard types.  The old type names are now type synonyms:
  1738 
  1739   hypreal = real star
  1740   hypnat = nat star
  1741   hcomplex = complex star
  1742 
  1743 * Hyperreal: Many groups of similarly-defined constants have been
  1744 replaced by polymorphic versions (INCOMPATIBILITY):
  1745 
  1746   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1747 
  1748   starset      <-- starsetNat, starsetC
  1749   *s*          <-- *sNat*, *sc*
  1750   starset_n    <-- starsetNat_n, starsetC_n
  1751   *sn*         <-- *sNatn*, *scn*
  1752   InternalSets <-- InternalNatSets, InternalCSets
  1753 
  1754   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1755   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1756   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1757   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1758   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1759 
  1760 * Hyperreal: Many type-specific theorems have been removed in favor of
  1761 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1762 
  1763   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1764   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1765   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1766   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1767   right_minus <-- hypreal_add_minus
  1768   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1769   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1770   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1771   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1772   mult_1_right <-- hcomplex_mult_one_right
  1773   mult_zero_left <-- hcomplex_mult_zero_left
  1774   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1775   right_distrib <-- hypnat_add_mult_distrib2
  1776   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1777   right_inverse <-- hypreal_mult_inverse
  1778   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1779   order_refl <-- {hypreal,hypnat}_le_refl
  1780   order_trans <-- {hypreal,hypnat}_le_trans
  1781   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1782   order_less_le <-- {hypreal,hypnat}_less_le
  1783   linorder_linear <-- {hypreal,hypnat}_le_linear
  1784   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1785   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1786   add_nonneg_nonneg <-- hypreal_le_add_order
  1787 
  1788 * Hyperreal: Separate theorems having to do with type-specific
  1789 versions of constants have been merged into theorems that apply to the
  1790 new polymorphic constants (INCOMPATIBILITY):
  1791 
  1792   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1793   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1794   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1795   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1796   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1797   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1798   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1799   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1800   STAR_diff <-- {STAR,STARC}_diff
  1801   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1802     STARC_hcomplex_of_complex}_image_subset
  1803   starset_n_Un <-- starset{Nat,C}_n_Un
  1804   starset_n_Int <-- starset{Nat,C}_n_Int
  1805   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1806   starset_n_diff <-- starset{Nat,C}_n_diff
  1807   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1808   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1809   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1810   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1811   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1812   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1813   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1814   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1815   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1816   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1817   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1818   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1819   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1820   starfun_diff <-- starfun{C,RC,CR}_diff
  1821   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1822   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1823   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1824   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1825   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1826   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1827   starfun_Id <-- starfunC_Id
  1828   starfun_approx <-- starfun{Nat,CR}_approx
  1829   starfun_capprox <-- starfun{C,RC}_capprox
  1830   starfun_abs <-- starfunNat_rabs
  1831   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1832   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1833   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1834   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1835   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1836   starfun_add_approx <-- starfunCR_add_approx
  1837   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1838   starfun_divide <-- starfun{C,CR,RC}_divide
  1839   starfun_n <-- starfun{Nat,C}_n
  1840   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1841   starfun_n_add <-- starfun{Nat,C}_n_add
  1842   starfun_n_add_minus <-- starfunNat_n_add_minus
  1843   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1844   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1845   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1846 
  1847   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1848   star_n_minus <-- {hypreal,hcomplex}_minus
  1849   star_n_diff <-- {hypreal,hcomplex}_diff
  1850   star_n_mult <-- {hypreal,hcomplex}_mult
  1851   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1852   star_n_le <-- {hypreal,hypnat}_le
  1853   star_n_less <-- {hypreal,hypnat}_less
  1854   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1855   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1856   star_n_abs <-- hypreal_hrabs
  1857   star_n_divide <-- hcomplex_divide
  1858 
  1859   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1860   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1861   star_of_diff <-- hypreal_of_real_diff
  1862   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1863   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1864   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1865   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1866   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1867   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1868   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1869   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1870   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1871   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1872   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1873   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1874   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1875   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1876   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1877   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1878   star_of_power <-- hypreal_of_real_power
  1879   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1880 
  1881 * Hyperreal: new method "transfer" that implements the transfer
  1882 principle of nonstandard analysis. With a subgoal that mentions
  1883 nonstandard types like "'a star", the command "apply transfer"
  1884 replaces it with an equivalent one that mentions only standard types.
  1885 To be successful, all free variables must have standard types; non-
  1886 standard variables must have explicit universal quantifiers.
  1887 
  1888 * Hyperreal: A theory of Taylor series.
  1889 
  1890 
  1891 *** HOLCF ***
  1892 
  1893 * Discontinued special version of 'constdefs' (which used to support
  1894 continuous functions) in favor of the general Pure one with full
  1895 type-inference.
  1896 
  1897 * New simplification procedure for solving continuity conditions; it
  1898 is much faster on terms with many nested lambda abstractions (cubic
  1899 instead of exponential time).
  1900 
  1901 * New syntax for domain package: selector names are now optional.
  1902 Parentheses should be omitted unless argument is lazy, for example:
  1903 
  1904   domain 'a stream = cons "'a" (lazy "'a stream")
  1905 
  1906 * New command 'fixrec' for defining recursive functions with pattern
  1907 matching; defining multiple functions with mutual recursion is also
  1908 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1909 sinr, or any data constructor defined by the domain package. The given
  1910 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1911 syntax and examples.
  1912 
  1913 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1914 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1915 but the proof obligation additionally includes an admissibility
  1916 requirement. The packages generate instances of class cpo or pcpo,
  1917 with continuity and strictness theorems for Rep and Abs.
  1918 
  1919 * HOLCF: Many theorems have been renamed according to a more standard naming
  1920 scheme (INCOMPATIBILITY):
  1921 
  1922   foo_inject:  "foo$x = foo$y ==> x = y"
  1923   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1924   foo_less:    "(foo$x << foo$y) = (x << y)"
  1925   foo_strict:  "foo$UU = UU"
  1926   foo_defined: "... ==> foo$x ~= UU"
  1927   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1928 
  1929 
  1930 *** ZF ***
  1931 
  1932 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1933 including the First Isomorphism Theorem (on quotienting by the kernel
  1934 of a homomorphism).
  1935 
  1936 * ZF/Simplifier: install second copy of type solver that actually
  1937 makes use of TC rules declared to Isar proof contexts (or locales);
  1938 the old version is still required for ML proof scripts.
  1939 
  1940 
  1941 *** Cube ***
  1942 
  1943 * Converted to Isar theory format; use locales instead of axiomatic
  1944 theories.
  1945 
  1946 
  1947 *** ML ***
  1948 
  1949 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1950 for ||>, ||>>, |>>,
  1951 
  1952 * Pure/library.ML no longer defines its own option datatype, but uses
  1953 that of the SML basis, which has constructors NONE and SOME instead of
  1954 None and Some, as well as exception Option.Option instead of OPTION.
  1955 The functions the, if_none, is_some, is_none have been adapted
  1956 accordingly, while Option.map replaces apsome.
  1957 
  1958 * Pure/library.ML: the exception LIST has been given up in favour of
  1959 the standard exceptions Empty and Subscript, as well as
  1960 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1961 superceded by the standard hd and tl functions etc.
  1962 
  1963 A number of basic list functions are no longer exported to the ML
  1964 toplevel, as they are variants of predefined functions.  The following
  1965 suggests how one can translate existing code:
  1966 
  1967     rev_append xs ys = List.revAppend (xs, ys)
  1968     nth_elem (i, xs) = List.nth (xs, i)
  1969     last_elem xs = List.last xs
  1970     flat xss = List.concat xss
  1971     seq fs = List.app fs
  1972     partition P xs = List.partition P xs
  1973     mapfilter f xs = List.mapPartial f xs
  1974 
  1975 * Pure/library.ML: several combinators for linear functional
  1976 transformations, notably reverse application and composition:
  1977 
  1978   x |> f                f #> g
  1979   (x, y) |-> f          f #-> g
  1980 
  1981 * Pure/library.ML: introduced/changed precedence of infix operators:
  1982 
  1983   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1984   infix 2 ?;
  1985   infix 3 o oo ooo oooo;
  1986   infix 4 ~~ upto downto;
  1987 
  1988 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1989 infix operators.
  1990 
  1991 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1992 fold_map support linear functional transformations and nesting.  For
  1993 example:
  1994 
  1995   fold f [x1, ..., xN] y =
  1996     y |> f x1 |> ... |> f xN
  1997 
  1998   (fold o fold) f [xs1, ..., xsN] y =
  1999     y |> fold f xs1 |> ... |> fold f xsN
  2000 
  2001   fold f [x1, ..., xN] =
  2002     f x1 #> ... #> f xN
  2003 
  2004   (fold o fold) f [xs1, ..., xsN] =
  2005     fold f xs1 #> ... #> fold f xsN
  2006 
  2007 * Pure/library.ML: the following selectors on type 'a option are
  2008 available:
  2009 
  2010   the:               'a option -> 'a  (*partial*)
  2011   these:             'a option -> 'a  where 'a = 'b list
  2012   the_default: 'a -> 'a option -> 'a
  2013   the_list:          'a option -> 'a list
  2014 
  2015 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2016 basic operations for association lists, following natural argument
  2017 order; moreover the explicit equality predicate passed here avoids
  2018 potentially expensive polymorphic runtime equality checks.
  2019 The old functions may be expressed as follows:
  2020 
  2021   assoc = uncurry (AList.lookup (op =))
  2022   assocs = these oo AList.lookup (op =)
  2023   overwrite = uncurry (AList.update (op =)) o swap
  2024 
  2025 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2026 
  2027   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2028   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2029 
  2030 replacing make_keylist and keyfilter (occassionally used)
  2031 Naive rewrites:
  2032 
  2033   make_keylist = AList.make
  2034   keyfilter = AList.find (op =)
  2035 
  2036 * eq_fst and eq_snd now take explicit equality parameter, thus
  2037   avoiding eqtypes. Naive rewrites:
  2038 
  2039     eq_fst = eq_fst (op =)
  2040     eq_snd = eq_snd (op =)
  2041 
  2042 * Removed deprecated apl and apr (rarely used).
  2043   Naive rewrites:
  2044 
  2045     apl (n, op) =>>= curry op n
  2046     apr (op, m) =>>= fn n => op (n, m)
  2047 
  2048 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2049 provides a reasonably efficient light-weight implementation of sets as
  2050 lists.
  2051 
  2052 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2053 few new operations; existing lookup and update are now curried to
  2054 follow natural argument order (for use with fold etc.);
  2055 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2056 
  2057 * Pure/General: output via the Isabelle channels of
  2058 writeln/warning/error etc. is now passed through Output.output, with a
  2059 hook for arbitrary transformations depending on the print_mode
  2060 (cf. Output.add_mode -- the first active mode that provides a output
  2061 function wins).  Already formatted output may be embedded into further
  2062 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2063 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2064 accommodate easy composition of diagnostic messages etc.  Programmers
  2065 rarely need to care about Output.output or Output.raw at all, with
  2066 some notable exceptions: Output.output is required when bypassing the
  2067 standard channels (writeln etc.), or in token translations to produce
  2068 properly formatted results; Output.raw is required when capturing
  2069 already output material that will eventually be presented to the user
  2070 a second time.  For the default print mode, both Output.output and
  2071 Output.raw have no effect.
  2072 
  2073 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2074 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2075 cumulative results are displayed at the end of a batch session.
  2076 
  2077 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2078 replaced by File.platform_path and File.shell_path (with appropriate
  2079 hooks).  This provides a clean interface for unusual systems where the
  2080 internal and external process view of file names are different.
  2081 
  2082 * Pure: more efficient orders for basic syntactic entities: added
  2083 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2084 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2085 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2086 orders now -- potential INCOMPATIBILITY for code that depends on a
  2087 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2088 Library.sort_strings on result).
  2089 
  2090 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2091 fold_types traverse types/terms from left to right, observing natural
  2092 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2093 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2094 
  2095 * Pure: name spaces have been refined, with significant changes of the
  2096 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2097 to extern(_table).  The plain name entry path is superceded by a
  2098 general 'naming' context, which also includes the 'policy' to produce
  2099 a fully qualified name and external accesses of a fully qualified
  2100 name; NameSpace.extend is superceded by context dependent
  2101 Sign.declare_name.  Several theory and proof context operations modify
  2102 the naming context.  Especially note Theory.restore_naming and
  2103 ProofContext.restore_naming to get back to a sane state; note that
  2104 Theory.add_path is no longer sufficient to recover from
  2105 Theory.absolute_path in particular.
  2106 
  2107 * Pure: new flags short_names (default false) and unique_names
  2108 (default true) for controlling output of qualified names.  If
  2109 short_names is set, names are printed unqualified.  If unique_names is
  2110 reset, the name prefix is reduced to the minimum required to achieve
  2111 the original result when interning again, even if there is an overlap
  2112 with earlier declarations.
  2113 
  2114 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2115 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2116 (useful for printing error messages).  INCOMPATIBILITY.
  2117 
  2118 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2119 Theory.theory are now identified, referring to the universal
  2120 Context.theory (see Pure/context.ML).  Actual signature and theory
  2121 content is managed as theory data.  The old code and interfaces were
  2122 spread over many files and structures; the new arrangement introduces
  2123 considerable INCOMPATIBILITY to gain more clarity:
  2124 
  2125   Context -- theory management operations (name, identity, inclusion,
  2126     parents, ancestors, merge, etc.), plus generic theory data;
  2127 
  2128   Sign -- logical signature and syntax operations (declaring consts,
  2129     types, etc.), plus certify/read for common entities;
  2130 
  2131   Theory -- logical theory operations (stating axioms, definitions,
  2132     oracles), plus a copy of logical signature operations (consts,
  2133     types, etc.); also a few basic management operations (Theory.copy,
  2134     Theory.merge, etc.)
  2135 
  2136 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2137 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2138 for convenience -- they merely return the theory.
  2139 
  2140 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2141 
  2142 * Pure: the Isar proof context type is already defined early in Pure
  2143 as Context.proof (note that ProofContext.context and Proof.context are
  2144 aliases, where the latter is the preferred name).  This enables other
  2145 Isabelle components to refer to that type even before Isar is present.
  2146 
  2147 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2148 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2149 any of these kinds.  For example, Sign.intern typeK is now
  2150 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2151 Theory.hide_types.  Also note that former
  2152 Theory.hide_classes/types/consts are now
  2153 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2154 internalize their arguments!  INCOMPATIBILITY.
  2155 
  2156 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2157 datatype thmref (with constructors Name and NameSelection) instead of
  2158 plain string -- INCOMPATIBILITY;
  2159 
  2160 * Pure: cases produced by proof methods specify options, where NONE
  2161 means to remove case bindings -- INCOMPATIBILITY in
  2162 (RAW_)METHOD_CASES.
  2163 
  2164 * Pure: the following operations retrieve axioms or theorems from a
  2165 theory node or theory hierarchy, respectively:
  2166 
  2167   Theory.axioms_of: theory -> (string * term) list
  2168   Theory.all_axioms_of: theory -> (string * term) list
  2169   PureThy.thms_of: theory -> (string * thm) list
  2170   PureThy.all_thms_of: theory -> (string * thm) list
  2171 
  2172 * Pure: print_tac now outputs the goal through the trace channel.
  2173 
  2174 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2175 Reference Toplevel.debug (default false) controls detailed printing
  2176 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2177 controls execution profiling -- set to 1 for time and 2 for space
  2178 (both increase the runtime).
  2179 
  2180 * Isar session: The initial use of ROOT.ML is now always timed,
  2181 i.e. the log will show the actual process times, in contrast to the
  2182 elapsed wall-clock time that the outer shell wrapper produces.
  2183 
  2184 * Simplifier: improved handling of bound variables (nameless
  2185 representation, avoid allocating new strings).  Simprocs that invoke
  2186 the Simplifier recursively should use Simplifier.inherit_bounds to
  2187 avoid local name clashes.  Failure to do so produces warnings
  2188 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2189 for further details.
  2190 
  2191 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2192 bindings for all theorems stored within a given theory; this may help
  2193 in porting non-Isar theories to Isar ones, while keeping ML proof
  2194 scripts for the time being.
  2195 
  2196 * ML operator HTML.with_charset specifies the charset begin used for
  2197 generated HTML files.  For example:
  2198 
  2199   HTML.with_charset "utf-8" use_thy "Hebrew";
  2200   HTML.with_charset "utf-8" use_thy "Chinese";
  2201 
  2202 
  2203 *** System ***
  2204 
  2205 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2206 isabelle, isatool etc.).
  2207 
  2208 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2209 isatool doc, isatool mkdir, display_drafts etc.).
  2210 
  2211 * isatool usedir: option -f allows specification of the ML file to be
  2212 used by Isabelle; default is ROOT.ML.
  2213 
  2214 * New isatool version outputs the version identifier of the Isabelle
  2215 distribution being used.
  2216 
  2217 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2218 (containing Boolean satisfiability problems) into Isabelle/HOL
  2219 theories.
  2220 
  2221 
  2222 
  2223 New in Isabelle2004 (April 2004)
  2224 --------------------------------
  2225 
  2226 *** General ***
  2227 
  2228 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2229   Replaces linorder.ML.
  2230 
  2231 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2232   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2233   (\<a>...\<z>), are now considered normal letters, and can therefore
  2234   be used anywhere where an ASCII letter (a...zA...Z) has until
  2235   now. COMPATIBILITY: This obviously changes the parsing of some
  2236   terms, especially where a symbol has been used as a binder, say
  2237   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2238   as an identifier.  Fix it by inserting a space around former
  2239   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2240   existing theory and ML files.
  2241 
  2242 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2243 
  2244 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2245   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2246   a normal (but invisible) letter. For multiple letter subscripts repeat
  2247   \<^isub> like this: x\<^isub>1\<^isub>2.
  2248 
  2249 * Pure: There are now sub-/superscripts that can span more than one
  2250   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2251   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2252   superscript. The new control characters are not identifier parts.
  2253 
  2254 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2255   content of "..." to the latex file instead of \isacntrl... . The "..."
  2256   may consist of any printable characters excluding the end bracket >.
  2257 
  2258 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2259   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2260   declare constants "final", which prevents their being given a definition
  2261   later.  It is useful for constants whose behaviour is fixed axiomatically
  2262   rather than definitionally, such as the meta-logic connectives.
  2263 
  2264 * Pure: 'instance' now handles general arities with general sorts
  2265   (i.e. intersections of classes),
  2266 
  2267 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2268   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2269   It can be changed to alter the colors/layout of generated pages.
  2270 
  2271 
  2272 *** Isar ***
  2273 
  2274 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2275   cut_tac, subgoal_tac and thin_tac:
  2276   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2277     locales are no longer forced to write Isar proof scripts.
  2278     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2279     emulations.
  2280   - INCOMPATIBILITY: names of variables to be instantiated may no
  2281     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2282     This is consistent with the instantiation attribute "where".
  2283 
  2284 * Attributes "where" and "of":
  2285   - Now take type variables of instantiated theorem into account when reading
  2286     the instantiation string.  This fixes a bug that caused instantiated
  2287     theorems to have too special types in some circumstances.
  2288   - "where" permits explicit instantiations of type variables.
  2289 
  2290 * Calculation commands "moreover" and "also" no longer interfere with
  2291   current facts ("this"), admitting arbitrary combinations with "then"
  2292   and derived forms.
  2293 
  2294 * Locales:
  2295   - Goal statements involving the context element "includes" no longer
  2296     generate theorems with internal delta predicates (those ending on
  2297     "_axioms") in the premise.
  2298     Resolve particular premise with <locale>.intro to obtain old form.
  2299   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2300     specification and "includes" elements in goal statement.
  2301   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2302     [intro?] and [elim?] (respectively) by default.
  2303   - Experimental command for instantiation of locales in proof contexts:
  2304         instantiate <label>[<attrs>]: <loc>
  2305     Instantiates locale <loc> and adds all its theorems to the current context
  2306     taking into account their attributes.  Label and attrs are optional
  2307     modifiers, like in theorem declarations.  If present, names of
  2308     instantiated theorems are qualified with <label>, and the attributes
  2309     <attrs> are applied after any attributes these theorems might have already.
  2310       If the locale has assumptions, a chained fact of the form
  2311     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2312     are derived.  The command does not support old-style locales declared
  2313     with "locale (open)".
  2314       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2315 
  2316 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2317   (Isar) contexts.
  2318 
  2319 
  2320 *** HOL ***
  2321 
  2322 * Proof import: new image HOL4 contains the imported library from
  2323   the HOL4 system with about 2500 theorems. It is imported by
  2324   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2325   can be used like any other Isabelle image.  See
  2326   HOL/Import/HOL/README for more information.
  2327 
  2328 * Simplifier:
  2329   - Much improved handling of linear and partial orders.
  2330     Reasoners for linear and partial orders are set up for type classes
  2331     "linorder" and "order" respectively, and are added to the default simpset
  2332     as solvers.  This means that the simplifier can build transitivity chains
  2333     to solve goals from the assumptions.
  2334   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2335     of blast or auto after simplification become unnecessary because the goal
  2336     is solved by simplification already.
  2337 
  2338 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2339     all proved in axiomatic type classes for semirings, rings and fields.
  2340 
  2341 * Numerics:
  2342   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2343     now formalized using the Ring_and_Field theory mentioned above.
  2344   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2345     than before, because now they are set up once in a generic manner.
  2346   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2347     Look for the general versions in Ring_and_Field (and Power if they concern
  2348     exponentiation).
  2349 
  2350 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2351 
  2352 * Records:
  2353   - Record types are now by default printed with their type abbreviation
  2354     instead of the list of all field types. This can be configured via
  2355     the reference "print_record_type_abbr".
  2356   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2357     (not enabled by default).
  2358   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2359     EX x. x = sel r to True (not enabled by default).
  2360   - Tactic "record_split_simp_tac" to split and simplify records added.
  2361 
  2362 * 'specification' command added, allowing for definition by
  2363   specification.  There is also an 'ax_specification' command that
  2364   introduces the new constants axiomatically.
  2365 
  2366 * arith(_tac) is now able to generate counterexamples for reals as well.
  2367 
  2368 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2369 
  2370 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2371   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2372 
  2373 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2374   matrix theory to linear programming.
  2375 
  2376 * Unions and Intersections:
  2377   The latex output syntax of UN and INT has been changed
  2378   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2379   i.e. the index formulae has become a subscript.
  2380   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2381 
  2382 * Unions and Intersections over Intervals:
  2383   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2384   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2385   like in normal math, and corresponding versions for < and for intersection.
  2386 
  2387 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2388   lexicographic dictonary ordering has been added as "lexord".
  2389 
  2390 * ML: the legacy theory structures Int and List have been removed. They had
  2391   conflicted with ML Basis Library structures having the same names.
  2392 
  2393 * 'refute' command added to search for (finite) countermodels.  Only works
  2394   for a fragment of HOL.  The installation of an external SAT solver is
  2395   highly recommended.  See "HOL/Refute.thy" for details.
  2396 
  2397 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2398   formulae under an assignment of free variables to random values.
  2399   In contrast to 'refute', it can deal with inductive datatypes,
  2400   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2401   for examples.
  2402 
  2403 
  2404 *** HOLCF ***
  2405 
  2406 * Streams now come with concatenation and are part of the HOLCF image
  2407 
  2408 
  2409 
  2410 New in Isabelle2003 (May 2003)
  2411 ------------------------------
  2412 
  2413 *** General ***
  2414 
  2415 * Provers/simplifier:
  2416 
  2417   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2418     Assumptions are now subject to complete mutual simplification,
  2419     not just from left to right. The simplifier now preserves
  2420     the order of assumptions.
  2421 
  2422     Potential INCOMPATIBILITY:
  2423 
  2424     -- simp sometimes diverges where the old version did
  2425        not, e.g. invoking simp on the goal
  2426 
  2427         [| P (f x); y = x; f x = f y |] ==> Q
  2428 
  2429        now gives rise to the infinite reduction sequence
  2430 
  2431         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2432 
  2433        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2434        kind of problem.
  2435 
  2436     -- Tactics combining classical reasoner and simplification (such as auto)
  2437        are also affected by this change, because many of them rely on
  2438        simp. They may sometimes diverge as well or yield a different numbers
  2439        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2440        in case of problems. Sometimes subsequent calls to the classical
  2441        reasoner will fail because a preceeding call to the simplifier too
  2442        eagerly simplified the goal, e.g. deleted redundant premises.
  2443 
  2444   - The simplifier trace now shows the names of the applied rewrite rules
  2445 
  2446   - You can limit the number of recursive invocations of the simplifier
  2447     during conditional rewriting (where the simplifie tries to solve the
  2448     conditions before applying the rewrite rule):
  2449     ML "simp_depth_limit := n"
  2450     where n is an integer. Thus you can force termination where previously
  2451     the simplifier would diverge.
  2452 
  2453   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2454 
  2455   - No longer aborts on failed congruence proof.  Instead, the
  2456     congruence is ignored.
  2457 
  2458 * Pure: New generic framework for extracting programs from constructive
  2459   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2460   as HOL/Extraction for some case studies.
  2461 
  2462 * Pure: The main goal of the proof state is no longer shown by default, only
  2463 the subgoals. This behaviour is controlled by a new flag.
  2464    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2465 (ML: Proof.show_main_goal).
  2466 
  2467 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2468 rules whose conclusion matches subgoal 1:
  2469       PG menu: Isabelle/Isar -> Show me -> matching rules
  2470 The rules are ordered by how closely they match the subgoal.
  2471 In particular, rules that solve a subgoal outright are displayed first
  2472 (or rather last, the way they are printed).
  2473 (ML: ProofGeneral.print_intros())
  2474 
  2475 * Pure: New flag trace_unify_fail causes unification to print
  2476 diagnostic information (PG: in trace buffer) when it fails. This is
  2477 useful for figuring out why single step proofs like rule, erule or
  2478 assumption failed.
  2479 
  2480 * Pure: Locale specifications now produce predicate definitions
  2481 according to the body of text (covering assumptions modulo local
  2482 definitions); predicate "loc_axioms" covers newly introduced text,
  2483 while "loc" is cumulative wrt. all included locale expressions; the
  2484 latter view is presented only on export into the global theory
  2485 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2486 on the old view without predicates;
  2487 
  2488 * Pure: predefined locales "var" and "struct" are useful for sharing
  2489 parameters (as in CASL, for example); just specify something like
  2490 ``var x + var y + struct M'' as import;
  2491 
  2492 * Pure: improved thms_containing: proper indexing of facts instead of
  2493 raw theorems; check validity of results wrt. current name space;
  2494 include local facts of proof configuration (also covers active
  2495 locales), cover fixed variables in index; may use "_" in term
  2496 specification; an optional limit for the number of printed facts may
  2497 be given (the default is 40);
  2498 
  2499 * Pure: disallow duplicate fact bindings within new-style theory files
  2500 (batch-mode only);
  2501 
  2502 * Provers: improved induct method: assumptions introduced by case
  2503 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2504 the goal statement); "foo" still refers to all facts collectively;
  2505 
  2506 * Provers: the function blast.overloaded has been removed: all constants
  2507 are regarded as potentially overloaded, which improves robustness in exchange
  2508 for slight decrease in efficiency;
  2509 
  2510 * Provers/linorder: New generic prover for transitivity reasoning over
  2511 linear orders.  Note: this prover is not efficient!
  2512 
  2513 * Isar: preview of problems to finish 'show' now produce an error
  2514 rather than just a warning (in interactive mode);
  2515 
  2516 
  2517 *** HOL ***
  2518 
  2519 * arith(_tac)
  2520 
  2521  - Produces a counter example if it cannot prove a goal.
  2522    Note that the counter example may be spurious if the goal is not a formula
  2523    of quantifier-free linear arithmetic.
  2524    In ProofGeneral the counter example appears in the trace buffer.
  2525 
  2526  - Knows about div k and mod k where k is a numeral of type nat or int.
  2527 
  2528  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2529    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2530    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2531 
  2532 * simp's arithmetic capabilities have been enhanced a bit: it now
  2533 takes ~= in premises into account (by performing a case split);
  2534 
  2535 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2536 are distributed over a sum of terms;
  2537 
  2538 * New tactic "trans_tac" and method "trans" instantiate
  2539 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2540 "<=", "<" and "=").
  2541 
  2542 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2543 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2544 
  2545 * 'typedef' command has new option "open" to suppress the set
  2546 definition;
  2547 
  2548 * functions Min and Max on finite sets have been introduced (theory
  2549 Finite_Set);
  2550 
  2551 * attribute [symmetric] now works for relations as well; it turns
  2552 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2553 
  2554 * induct over a !!-quantified statement (say !!x1..xn):
  2555   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2556 
  2557 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2558 %x. None. Warning: empty_def now refers to the previously hidden definition
  2559 of the empty set.
  2560 
  2561 * Algebra: formalization of classical algebra.  Intended as base for
  2562 any algebraic development in Isabelle.  Currently covers group theory
  2563 (up to Sylow's theorem) and ring theory (Universal Property of
  2564 Univariate Polynomials).  Contributions welcome;
  2565 
  2566 * GroupTheory: deleted, since its material has been moved to Algebra;
  2567 
  2568 * Complex: new directory of the complex numbers with numeric constants,
  2569 nonstandard complex numbers, and some complex analysis, standard and
  2570 nonstandard (Jacques Fleuriot);
  2571 
  2572 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2573 
  2574 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2575 Fleuriot);
  2576 
  2577 * Real/HahnBanach: updated and adapted to locales;
  2578 
  2579 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2580 Gray and Kramer);
  2581 
  2582 * UNITY: added the Meier-Sanders theory of progress sets;
  2583 
  2584 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2585 as abstract algorithms, instantiated to the JVM;
  2586 
  2587 * Bali: Java source language formalization. Type system, operational
  2588 semantics, axiomatic semantics. Supported language features:
  2589 classes, interfaces, objects,virtual methods, static methods,
  2590 static/instance fields, arrays, access modifiers, definite
  2591 assignment, exceptions.
  2592 
  2593 
  2594 *** ZF ***
  2595 
  2596 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2597 universe, etc.);
  2598 
  2599 * Main ZF: virtually all theories converted to new-style format;
  2600 
  2601 
  2602 *** ML ***
  2603 
  2604 * Pure: Tactic.prove provides sane interface for internal proofs;
  2605 omits the infamous "standard" operation, so this is more appropriate
  2606 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2607 
  2608 * Pure: improved error reporting of simprocs;
  2609 
  2610 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2611 up simprocs;
  2612 
  2613 
  2614 *** Document preparation ***
  2615 
  2616 * uses \par instead of \\ for line breaks in theory text. This may
  2617 shift some page breaks in large documents. To get the old behaviour
  2618 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2619 
  2620 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2621 other packages
  2622 
  2623 * \<euro> now needs package babel/greek instead of marvosym (which
  2624 broke \Rightarrow)
  2625 
  2626 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2627 textcomp package)
  2628 
  2629 
  2630 
  2631 New in Isabelle2002 (March 2002)
  2632 --------------------------------
  2633 
  2634 *** Document preparation ***
  2635 
  2636 * greatly simplified document preparation setup, including more
  2637 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2638 instructive isatool mkdir; users should basically be able to get
  2639 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2640 users may run a separate document processing stage manually like this:
  2641 "isatool usedir -D output HOL Test && isatool document Test/output";
  2642 
  2643 * theory dependency graph may now be incorporated into documents;
  2644 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2645 with \includegraphics of LaTeX;
  2646 
  2647 * proper spacing of consecutive markup elements, especially text
  2648 blocks after section headings;
  2649 
  2650 * support bold style (for single symbols only), input syntax is like
  2651 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2652 
  2653 * \<bullet> is now output as bold \cdot by default, which looks much
  2654 better in printed text;
  2655 
  2656 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2657 note that these symbols are currently unavailable in Proof General /
  2658 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2659 
  2660 * isatool latex no longer depends on changed TEXINPUTS, instead
  2661 isatool document copies the Isabelle style files to the target
  2662 location;
  2663 
  2664 
  2665 *** Isar ***
  2666 
  2667 * Pure/Provers: improved proof by cases and induction;
  2668   - 'case' command admits impromptu naming of parameters (such as
  2669     "case (Suc n)");
  2670   - 'induct' method divinates rule instantiation from the inductive
  2671     claim; no longer requires excessive ?P bindings for proper
  2672     instantiation of cases;
  2673   - 'induct' method properly enumerates all possibilities of set/type
  2674     rules; as a consequence facts may be also passed through *type*
  2675     rules without further ado;
  2676   - 'induct' method now derives symbolic cases from the *rulified*
  2677     rule (before it used to rulify cases stemming from the internal
  2678     atomized version); this means that the context of a non-atomic
  2679     statement becomes is included in the hypothesis, avoiding the
  2680     slightly cumbersome show "PROP ?case" form;
  2681   - 'induct' may now use elim-style induction rules without chaining
  2682     facts, using ``missing'' premises from the goal state; this allows
  2683     rules stemming from inductive sets to be applied in unstructured
  2684     scripts, while still benefitting from proper handling of non-atomic
  2685     statements; NB: major inductive premises need to be put first, all
  2686     the rest of the goal is passed through the induction;
  2687   - 'induct' proper support for mutual induction involving non-atomic
  2688     rule statements (uses the new concept of simultaneous goals, see
  2689     below);
  2690   - append all possible rule selections, but only use the first
  2691     success (no backtracking);
  2692   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2693   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2694   - added 'print_induct_rules' (covered by help item in recent Proof
  2695     General versions);
  2696   - moved induct/cases attributes to Pure, methods to Provers;
  2697   - generic method setup instantiated for FOL and HOL;
  2698 
  2699 * Pure: support multiple simultaneous goal statements, for example
  2700 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2701 meta-level mechanism, this acts as if several individual goals had
  2702 been stated separately; in particular common proof methods need to be
  2703 repeated in order to cover all claims; note that a single elimination
  2704 step is *not* sufficient to establish the two conjunctions, so this
  2705 fails:
  2706 
  2707   assume "A & B" then have A and B ..   (*".." fails*)
  2708 
  2709 better use "obtain" in situations as above; alternative refer to
  2710 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2711 
  2712 * Pure: proper integration with ``locales''; unlike the original
  2713 version by Florian Kammller, Isar locales package high-level proof
  2714 contexts rather than raw logical ones (e.g. we admit to include
  2715 attributes everywhere); operations on locales include merge and
  2716 rename; support for implicit arguments (``structures''); simultaneous
  2717 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2718 some examples;
  2719 
  2720 * Pure: the following commands have been ``localized'', supporting a
  2721 target locale specification "(in name)": 'lemma', 'theorem',
  2722 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2723 stored both within the locale and at the theory level (exported and
  2724 qualified by the locale name);
  2725 
  2726 * Pure: theory goals may now be specified in ``long'' form, with
  2727 ad-hoc contexts consisting of arbitrary locale elements. for example
  2728 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2729 definitions may be given, too); the result is a meta-level rule with
  2730 the context elements being discharged in the obvious way;
  2731 
  2732 * Pure: new proof command 'using' allows to augment currently used
  2733 facts after a goal statement ('using' is syntactically analogous to
  2734 'apply', but acts on the goal's facts only); this allows chained facts
  2735 to be separated into parts given before and after a claim, as in
  2736 ``from a and b have C using d and e <proof>'';
  2737 
  2738 * Pure: renamed "antecedent" case to "rule_context";
  2739 
  2740 * Pure: new 'judgment' command records explicit information about the
  2741 object-logic embedding (used by several tools internally); no longer
  2742 use hard-wired "Trueprop";
  2743 
  2744 * Pure: added 'corollary' command;
  2745 
  2746 * Pure: fixed 'token_translation' command;
  2747 
  2748 * Pure: removed obsolete 'exported' attribute;
  2749 
  2750 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2751 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2752 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2753 
  2754 * Pure: method 'atomize' presents local goal premises as object-level
  2755 statements (atomic meta-level propositions); setup controlled via
  2756 rewrite rules declarations of 'atomize' attribute; example
  2757 application: 'induct' method with proper rule statements in improper
  2758 proof *scripts*;
  2759 
  2760 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2761 now consider the syntactic context of assumptions, giving a better
  2762 chance to get type-inference of the arguments right (this is
  2763 especially important for locales);
  2764 
  2765 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2766 mode;
  2767 
  2768 * Pure/obtain: the formal conclusion "thesis", being marked as
  2769 ``internal'', may no longer be reference directly in the text;
  2770 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2771 situations;
  2772 
  2773 * Pure: generic 'sym' attribute which declares a rule both as pure
  2774 'elim?' and for the 'symmetric' operation;
  2775 
  2776 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2777 text; the fixed correlation with particular command syntax has been
  2778 discontinued;
  2779 
  2780 * Pure: new method 'rules' is particularly well-suited for proof
  2781 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2782 but often produces more compact proof terms with less detours;
  2783 
  2784 * Pure/Provers/classical: simplified integration with pure rule
  2785 attributes and methods; the classical "intro?/elim?/dest?"
  2786 declarations coincide with the pure ones; the "rule" method no longer
  2787 includes classically swapped intros; "intro" and "elim" methods no
  2788 longer pick rules from the context; also got rid of ML declarations
  2789 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2790 INCOMPATIBILITY;
  2791 
  2792 * Provers/classical: attribute 'swapped' produces classical inversions
  2793 of introduction rules;
  2794 
  2795 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2796 rules instead of full simplifier context; 'iff' attribute handles
  2797 conditional rules;
  2798 
  2799 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2800 
  2801 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2802 "(permissive)" option to recover old behavior;
  2803 
  2804 * HOL: 'inductive' no longer features separate (collective) attributes
  2805 for 'intros' (was found too confusing);
  2806 
  2807 * HOL: properly declared induction rules less_induct and
  2808 wf_induct_rule;
  2809 
  2810 
  2811 *** HOL ***
  2812 
  2813 * HOL: moved over to sane numeral syntax; the new policy is as
  2814 follows:
  2815 
  2816   - 0 and 1 are polymorphic constants, which are defined on any
  2817   numeric type (nat, int, real etc.);
  2818 
  2819   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2820   binary representation internally;
  2821 
  2822   - type nat has special constructor Suc, and generally prefers Suc 0
  2823   over 1::nat and Suc (Suc 0) over 2::nat;
  2824 
  2825 This change may cause significant problems of INCOMPATIBILITY; here
  2826 are some hints on converting existing sources:
  2827 
  2828   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2829   entities, so expressions involving "-" (unary or binary minus) need
  2830   to be spaced properly;
  2831 
  2832   - existing occurrences of "1" may need to be constraint "1::nat" or
  2833   even replaced by Suc 0; similar for old "2";
  2834 
  2835   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2836 
  2837   - remove all special provisions on numerals in proofs;
  2838 
  2839 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2840 representation (depends on bin_arith_simps in the default context);
  2841 
  2842 * HOL: symbolic syntax for x^2 (numeral 2);
  2843 
  2844 * HOL: the class of all HOL types is now called "type" rather than
  2845 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2846 in axclass/classes, instance/arities, and (usually rare) occurrences
  2847 in typings (of consts etc.); internally the class is called
  2848 "HOL.type", ML programs should refer to HOLogic.typeS;
  2849 
  2850 * HOL/record package improvements:
  2851   - new derived operations "fields" to build a partial record section,
  2852     "extend" to promote a fixed record to a record scheme, and
  2853     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2854     declared as simp by default;
  2855   - shared operations ("more", "fields", etc.) now need to be always
  2856     qualified) --- potential INCOMPATIBILITY;
  2857   - removed "make_scheme" operations (use "make" with "extend") --
  2858     INCOMPATIBILITY;
  2859   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2860   - provides cases/induct rules for use with corresponding Isar
  2861     methods (for concrete records, record schemes, concrete more
  2862     parts, and schematic more parts -- in that order);
  2863   - internal definitions directly based on a light-weight abstract
  2864     theory of product types over typedef rather than datatype;
  2865 
  2866 * HOL: generic code generator for generating executable ML code from
  2867 specifications; specific support for HOL constructs such as inductive
  2868 datatypes and sets, as well as recursive functions; can be invoked
  2869 via 'generate_code' theory section;
  2870 
  2871 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2872 
  2873 * HOL: consolidated and renamed several theories.  In particular:
  2874         Ord.thy has been absorbed into HOL.thy
  2875         String.thy has been absorbed into List.thy
  2876 
  2877 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2878 (beware of argument permutation!);
  2879 
  2880 * HOL: linorder_less_split superseded by linorder_cases;
  2881 
  2882 * HOL/List: "nodups" renamed to "distinct";
  2883 
  2884 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2885 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2886   - Ex_def has changed, now need to use some_eq_ex
  2887 
  2888 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2889 in this (rare) case use:
  2890 
  2891   delSWrapper "split_all_tac"
  2892   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2893 
  2894 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2895 MAY FAIL;
  2896 
  2897 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2898 Isabelle's type classes, ^ on functions and relations has too general
  2899 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2900 necessary to attach explicit type constraints;
  2901 
  2902 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2903 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2904 renamed accordingly (eg "compI" -> "rel_compI").
  2905 
  2906 * HOL: syntax translations now work properly with numerals and records
  2907 expressions;
  2908 
  2909 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2910 of "lam" -- INCOMPATIBILITY;
  2911 
  2912 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2913 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2914 renamed "Product_Type.unit";
  2915 
  2916 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2917 
  2918 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2919 the "cases" method);
  2920 
  2921 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2922 Florian Kammller);
  2923 
  2924 * HOL/IMP: updated and converted to new-style theory format; several
  2925 parts turned into readable document, with proper Isar proof texts and
  2926 some explanations (by Gerwin Klein);
  2927 
  2928 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2929 
  2930 * HOL-Hyperreal is now a logic image;
  2931 
  2932 
  2933 *** HOLCF ***
  2934 
  2935 * Isar: consts/constdefs supports mixfix syntax for continuous
  2936 operations;
  2937 
  2938 * Isar: domain package adapted to new-style theory format, e.g. see
  2939 HOLCF/ex/Dnat.thy;
  2940 
  2941 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2942 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2943 lift.induct_tac, always use UU instead of Undef;
  2944 
  2945 * HOLCF/IMP: updated and converted to new-style theory;
  2946 
  2947 
  2948 *** ZF ***
  2949 
  2950 * Isar: proper integration of logic-specific tools and packages,
  2951 including theory commands '(co)inductive', '(co)datatype',
  2952 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2953 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2954 
  2955 * theory Main no longer includes AC; for the Axiom of Choice, base
  2956 your theory on Main_ZFC;
  2957 
  2958 * the integer library now covers quotients and remainders, with many
  2959 laws relating division to addition, multiplication, etc.;
  2960 
  2961 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2962 typeless version of the formalism;
  2963 
  2964 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2965 format;
  2966 
  2967 * ZF/Induct: new directory for examples of inductive definitions,
  2968 including theory Multiset for multiset orderings; converted to
  2969 new-style theory format;
  2970 
  2971 * ZF: many new theorems about lists, ordinals, etc.;
  2972 
  2973 
  2974 *** General ***
  2975 
  2976 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2977 variable proof controls level of detail: 0 = no proofs (only oracle
  2978 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2979 also ref manual for further ML interfaces;
  2980 
  2981 * Pure/axclass: removed obsolete ML interface
  2982 goal_subclass/goal_arity;
  2983 
  2984 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2985 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2986 separate tokens, so expressions involving minus need to be spaced
  2987 properly;
  2988 
  2989 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2990 rather than "infixl" or "infixr";
  2991 
  2992 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2993 sort constraint specifications in type inference; e.g. "x::_::foo"
  2994 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2995 type variable);
  2996 
  2997 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2998 control output of nested => (types); the default behavior is
  2999 "type_brackets";
  3000 
  3001 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3002 tokens into AST constants;
  3003 
  3004 * Pure/syntax: prefer later declarations of translations and print
  3005 translation functions; potential INCOMPATIBILITY: need to reverse
  3006 multiple declarations for same syntax element constant;
  3007 
  3008 * Pure/show_hyps reset by default (in accordance to existing Isar
  3009 practice);
  3010 
  3011 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3012 addSafter;
  3013 
  3014 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3015 as well;
  3016 
  3017 * system: tested support for MacOS X; should be able to get Isabelle +
  3018 Proof General to work in a plain Terminal after installing Poly/ML
  3019 (e.g. from the Isabelle distribution area) and GNU bash alone
  3020 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3021 support requires further installations, e.g. from
  3022 http://fink.sourceforge.net/);
  3023 
  3024 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3025 
  3026 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3027 of 40 MB), cf. ML_OPTIONS;
  3028 
  3029 * system: Proof General keywords specification is now part of the
  3030 Isabelle distribution (see etc/isar-keywords.el);
  3031 
  3032 * system: support for persistent Proof General sessions (refrain from
  3033 outdating all loaded theories on startup); user may create writable
  3034 logic images like this: ``isabelle -q HOL Test'';
  3035 
  3036 * system: smart selection of Isabelle process versus Isabelle
  3037 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3038 run both "isabelle" and "Isabelle" even if file names are badly
  3039 damaged (executable inspects the case of the first letter of its own
  3040 name); added separate "isabelle-process" and "isabelle-interface";
  3041 
  3042 * system: refrain from any attempt at filtering input streams; no
  3043 longer support ``8bit'' encoding of old isabelle font, instead proper
  3044 iso-latin characters may now be used; the related isatools
  3045 "symbolinput" and "nonascii" have disappeared as well;
  3046 
  3047 * system: removed old "xterm" interface (the print modes "xterm" and
  3048 "xterm_color" are still available for direct use in a suitable
  3049 terminal);
  3050 
  3051 
  3052 
  3053 New in Isabelle99-2 (February 2001)
  3054 -----------------------------------
  3055 
  3056 *** Overview of INCOMPATIBILITIES ***
  3057 
  3058 * HOL: please note that theories in the Library and elsewhere often use the
  3059 new-style (Isar) format; to refer to their theorems in an ML script you must
  3060 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3061 
  3062 * HOL: inductive package no longer splits induction rule aggressively,
  3063 but only as far as specified by the introductions given; the old
  3064 format may be recovered via ML function complete_split_rule or attribute
  3065 'split_rule (complete)';
  3066 
  3067 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3068 gfp_Tarski to gfp_unfold;
  3069 
  3070 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3071 
  3072 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3073 relation); infix "^^" has been renamed "``"; infix "``" has been
  3074 renamed "`"; "univalent" has been renamed "single_valued";
  3075 
  3076 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3077 operation;
  3078 
  3079 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3080 
  3081 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3082 
  3083 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3084 consequence, it is no longer monotonic wrt. the local goal context
  3085 (which is now passed through the inductive cases);
  3086 
  3087 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3088 \<gg> to \<ggreater>;
  3089 
  3090 
  3091 *** Document preparation ***
  3092 
  3093 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3094 available: are "it" for near math-mode best-style output, "sl" for
  3095 slanted text style, and "tt" for plain type-writer; if no
  3096 \isabellestyle command is given, output is according to slanted
  3097 type-writer);
  3098 
  3099 * support sub/super scripts (for single symbols only), input syntax is
  3100 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3101 
  3102 * some more standard symbols; see Appendix A of the system manual for
  3103 the complete list of symbols defined in isabellesym.sty;
  3104 
  3105 * improved isabelle style files; more abstract symbol implementation
  3106 (should now use \isamath{...} and \isatext{...} in custom symbol
  3107 definitions);
  3108 
  3109 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3110 state; Note that presentation of goal states does not conform to
  3111 actual human-readable proof documents.  Please do not include goal
  3112 states into document output unless you really know what you are doing!
  3113 
  3114 * proper indentation of antiquoted output with proportional LaTeX
  3115 fonts;
  3116 
  3117 * no_document ML operator temporarily disables LaTeX document
  3118 generation;
  3119 
  3120 * isatool unsymbolize tunes sources for plain ASCII communication;
  3121 
  3122 
  3123 *** Isar ***
  3124 
  3125 * Pure: Isar now suffers initial goal statements to contain unbound
  3126 schematic variables (this does not conform to actual readable proof
  3127 documents, due to unpredictable outcome and non-compositional proof
  3128 checking); users who know what they are doing may use schematic goals
  3129 for Prolog-style synthesis of proven results;
  3130 
  3131 * Pure: assumption method (an implicit finishing) now handles actual
  3132 rules as well;
  3133 
  3134 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3135 initial goal, declare "that" only as Pure intro (only for single
  3136 steps); the "that" rule assumption may now be involved in implicit
  3137 finishing, thus ".." becomes a feasible for trivial obtains;
  3138 
  3139 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3140 instance proofs may be performed by "..";
  3141 
  3142 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3143 statements as well;
  3144 
  3145 * Pure: more robust selection of calculational rules;
  3146 
  3147 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3148 rule (as well as the assumption rule);
  3149 
  3150 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3151 lemmas, using the graph browser tool;
  3152 
  3153 * Pure: predict failure of "show" in interactive mode;
  3154 
  3155 * Pure: 'thms_containing' now takes actual terms as arguments;
  3156 
  3157 * HOL: improved method 'induct' --- now handles non-atomic goals
  3158 (potential INCOMPATIBILITY); tuned error handling;
  3159 
  3160 * HOL: cases and induct rules now provide explicit hints about the
  3161 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3162 any remaining facts are inserted into the goal verbatim;
  3163 
  3164 * HOL: local contexts (aka cases) may now contain term bindings as
  3165 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3166 the result to be shown in each case;
  3167 
  3168 * HOL: added 'recdef_tc' command;
  3169 
  3170 * isatool convert assists in eliminating legacy ML scripts;
  3171 
  3172 
  3173 *** HOL ***
  3174 
  3175 * HOL/Library: a collection of generic theories to be used together
  3176 with main HOL; the theory loader path already includes this directory
  3177 by default; the following existing theories have been moved here:
  3178 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3179 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3180 
  3181 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3182 modelling and verification task performed in Isabelle/HOL +
  3183 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3184 
  3185 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3186 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3187 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3188 'domain', this makes the theory consistent with mathematical
  3189 literature;
  3190 
  3191 * HOL basics: added overloaded operations "inverse" and "divide"
  3192 (infix "/"), syntax for generic "abs" operation, generic summation
  3193 operator \<Sum>;
  3194 
  3195 * HOL/typedef: simplified package, provide more useful rules (see also
  3196 HOL/subset.thy);
  3197 
  3198 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3199 now expressed as a proper nested rule (old-style tactic scripts may
  3200 require atomize_strip_tac to cope with non-atomic premises);
  3201 
  3202 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3203 to "split_conv" (old name still available for compatibility);
  3204 
  3205 * HOL: improved concrete syntax for strings (e.g. allows translation
  3206 rules with string literals);
  3207 
  3208 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3209  and Fleuriot's mechanization of analysis, including the transcendental
  3210  functions for the reals;
  3211 
  3212 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3213 
  3214 
  3215 *** CTT ***
  3216 
  3217 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3218 "lam" is displayed as TWO lambda-symbols
  3219 
  3220 * CTT: theory Main now available, containing everything (that is, Bool
  3221 and Arith);
  3222 
  3223 
  3224 *** General ***
  3225 
  3226 * Pure: the Simplifier has been implemented properly as a derived rule
  3227 outside of the actual kernel (at last!); the overall performance
  3228 penalty in practical applications is about 50%, while reliability of
  3229 the Isabelle inference kernel has been greatly improved;
  3230 
  3231 * print modes "brackets" and "no_brackets" control output of nested =>
  3232 (types) and ==> (props); the default behaviour is "brackets";
  3233 
  3234 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3235 as assumptions as well;
  3236 
  3237 * system: support Poly/ML 4.0;
  3238 
  3239 * system: isatool install handles KDE version 1 or 2;
  3240 
  3241 
  3242 
  3243 New in Isabelle99-1 (October 2000)
  3244 ----------------------------------
  3245 
  3246 *** Overview of INCOMPATIBILITIES ***
  3247 
  3248 * HOL: simplification of natural numbers is much changed; to partly
  3249 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3250 issue the following ML commands:
  3251 
  3252   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3253   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3254 
  3255 * HOL: simplification no longer dives into case-expressions; this is
  3256 controlled by "t.weak_case_cong" for each datatype t;
  3257 
  3258 * HOL: nat_less_induct renamed to less_induct;
  3259 
  3260 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3261 fixsome to patch .thy and .ML sources automatically;
  3262 
  3263   select_equality  -> some_equality
  3264   select_eq_Ex     -> some_eq_ex
  3265   selectI2EX       -> someI2_ex
  3266   selectI2         -> someI2
  3267   selectI          -> someI
  3268   select1_equality -> some1_equality
  3269   Eps_sym_eq       -> some_sym_eq_trivial
  3270   Eps_eq           -> some_eq_trivial
  3271 
  3272 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3273 
  3274 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3275 instead);
  3276 
  3277 * HOL: the recursion equations generated by 'recdef' are now called
  3278 f.simps instead of f.rules;
  3279 
  3280 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3281 
  3282 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3283 sometimes be needed;
  3284 
  3285 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3286 
  3287 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3288 
  3289 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3290 product is now "<*>" instead of "Times"; the lexicographic product is
  3291 now "<*lex*>" instead of "**";
  3292 
  3293 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3294 of main HOL, but was unused); better use HOL's datatype package;
  3295 
  3296 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3297 the old syntax may be recovered as follows:
  3298 
  3299   syntax (symbols)
  3300     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3301       (infixl "\\<oplus>" 100)
  3302 
  3303 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3304 
  3305 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3306 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3307 internally;
  3308 
  3309 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3310 changed from A/r to A//r;
  3311 
  3312 * ZF: new treatment of arithmetic (nat & int) may break some old
  3313 proofs;
  3314 
  3315 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3316 rulify -> rule_format, elimify -> elim_format, ...);
  3317 
  3318 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3319 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3320 should have to change intro!! to intro? only); replaced "delrule" by
  3321 "rule del";
  3322 
  3323 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3324 
  3325 * Provers: strengthened force_tac by using new first_best_tac;
  3326 
  3327 * LaTeX document preparation: several changes of isabelle.sty (see
  3328 lib/texinputs);
  3329 
  3330 
  3331 *** Document preparation ***
  3332 
  3333 * formal comments (text blocks etc.) in new-style theories may now
  3334 contain antiquotations of thm/prop/term/typ/text to be presented
  3335 according to latex print mode; concrete syntax is like this:
  3336 @{term[show_types] "f(x) = a + x"};
  3337 
  3338 * isatool mkdir provides easy setup of Isabelle session directories,
  3339 including proper document sources;
  3340 
  3341 * generated LaTeX sources are now deleted after successful run
  3342 (isatool document -c); may retain a copy somewhere else via -D option
  3343 of isatool usedir;
  3344 
  3345 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3346 style files, achieving self-contained LaTeX sources and simplifying
  3347 LaTeX debugging;
  3348 
  3349 * old-style theories now produce (crude) LaTeX output as well;
  3350 
  3351 * browser info session directories are now self-contained (may be put
  3352 on WWW server seperately); improved graphs of nested sessions; removed
  3353 graph for 'all sessions';
  3354 
  3355 * several improvements in isabelle style files; \isabellestyle{it}
  3356 produces fake math mode output; \isamarkupheader is now \section by
  3357 default; see lib/texinputs/isabelle.sty etc.;
  3358 
  3359 
  3360 *** Isar ***
  3361 
  3362 * Isar/Pure: local results and corresponding term bindings are now
  3363 subject to Hindley-Milner polymorphism (similar to ML); this
  3364 accommodates incremental type-inference very nicely;
  3365 
  3366 * Isar/Pure: new derived language element 'obtain' supports
  3367 generalized existence reasoning;
  3368 
  3369 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3370 support accumulation of results, without applying any rules yet;
  3371 useful to collect intermediate results without explicit name
  3372 references, and for use with transitivity rules with more than 2
  3373 premises;
  3374 
  3375 * Isar/Pure: scalable support for case-analysis type proofs: new
  3376 'case' language element refers to local contexts symbolically, as
  3377 produced by certain proof methods; internally, case names are attached
  3378 to theorems as "tags";
  3379 
  3380 * Isar/Pure: theory command 'hide' removes declarations from
  3381 class/type/const name spaces;
  3382 
  3383 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3384 indicate potential overloading;
  3385 
  3386 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3387 
  3388 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3389 "{a,b,c}" instead of {a,b,c};
  3390 
  3391 * Isar/Pure now provides its own version of intro/elim/dest
  3392 attributes; useful for building new logics, but beware of confusion
  3393 with the version in Provers/classical;
  3394 
  3395 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3396 case name 'antecedent';
  3397 
  3398 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3399 to the current context is now done automatically);
  3400 
  3401 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3402 for definining proof methods in ML;
  3403 
  3404 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3405 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3406 most cases, one should have to change intro!! to intro? only);
  3407 replaced "delrule" by "rule del";
  3408 
  3409 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3410 'symmetric' attribute (the latter supercedes [RS sym]);
  3411 
  3412 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3413 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3414 well (including splits);
  3415 
  3416 * Isar/Provers: Simplifier and Classical methods now support all kind
  3417 of modifiers used in the past, including 'cong', 'iff', etc.
  3418 
  3419 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3420 of Simplifier and Classical reasoner);
  3421 
  3422 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3423 now support named cases; major packages (inductive, datatype, primrec,
  3424 recdef) support case names and properly name parameters;
  3425 
  3426 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3427 monotonicity conditions are extracted to be proven at end of
  3428 calculations;
  3429 
  3430 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3431 method anyway;
  3432 
  3433 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3434 split_if split_if_asm; datatype package provides theorems foo.splits =
  3435 foo.split foo.split_asm for each datatype;
  3436 
  3437 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3438 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3439 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3440 use "(cases (simplified))" method in proper proof texts);
  3441 
  3442 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3443 
  3444 * Isar: names of theorems etc. may be natural numbers as well;
  3445 
  3446 * Isar: 'pr' command: optional arguments for goals_limit and
  3447 ProofContext.prems_limit; no longer prints theory contexts, but only
  3448 proof states;
  3449 
  3450 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3451 additional print modes to be specified; e.g. "pr(latex)" will print
  3452 proof state according to the Isabelle LaTeX style;
  3453 
  3454 * Isar: improved support for emulating tactic scripts, including proof
  3455 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3456 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3457 (for HOL datatypes);
  3458 
  3459 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3460 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3461 'proof method scripts' have to be in depth-first order;
  3462 
  3463 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3464 
  3465 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3466 should instead use individual commands for printing items
  3467 (print_commands, print_methods etc.);
  3468 
  3469 * Isar: added 'nothing' --- the empty list of theorems;
  3470 
  3471 
  3472 *** HOL ***
  3473 
  3474 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3475 corresponding virtual machine and a specification of its bytecode
  3476 verifier and a lightweight bytecode verifier, including proofs of
  3477 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3478 Cornelia Pusch (see also the homepage of project Bali at
  3479 http://isabelle.in.tum.de/Bali/);
  3480 
  3481 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3482 Clemens Ballarin;
  3483 
  3484 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3485 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3486 Rasmussen;
  3487 
  3488 * HOL/Lattice: fundamental concepts of lattice theory and order
  3489 structures, including duals, properties of bounds versus algebraic
  3490 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3491 Theorem for complete lattices etc.; may also serve as a demonstration
  3492 for abstract algebraic reasoning using axiomatic type classes, and
  3493 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3494 
  3495 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3496 von Oheimb;
  3497 
  3498 * HOL/IMPP: extension of IMP with local variables and mutually
  3499 recursive procedures, by David von Oheimb;
  3500 
  3501 * HOL/Lambda: converted into new-style theory and document;
  3502 
  3503 * HOL/ex/Multiquote: example of multiple nested quotations and
  3504 anti-quotations -- basically a generalized version of de-Bruijn
  3505 representation; very useful in avoiding lifting of operations;
  3506 
  3507 * HOL/record: added general record equality rule to simpset; fixed
  3508 select-update simplification procedure to handle extended records as
  3509 well; admit "r" as field name;
  3510 
  3511 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3512 other numeric types and also as the identity of groups, rings, etc.;
  3513 
  3514 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3515 Types nat and int belong to this axclass;
  3516 
  3517 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3518    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3519    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3520   two terms #m*u and #n*u are replaced by #(m+n)*u
  3521     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3522   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3523     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3524 
  3525 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3526 powerful prover for predicate logic but knows nothing of clasets; see
  3527 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3528 
  3529 * HOL: new version of "case_tac" subsumes both boolean case split and
  3530 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3531 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3532 
  3533 * HOL: simplification no longer dives into case-expressions: only the
  3534 selector expression is simplified, but not the remaining arms; to
  3535 enable full simplification of case-expressions for datatype t, you may
  3536 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3537 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3538 
  3539 * HOL/recdef: the recursion equations generated by 'recdef' for
  3540 function 'f' are now called f.simps instead of f.rules; if all
  3541 termination conditions are proved automatically, these simplification
  3542 rules are added to the simpset, as in primrec; rules may be named
  3543 individually as well, resulting in a separate list of theorems for
  3544 each equation;
  3545 
  3546 * HOL/While is a new theory that provides a while-combinator. It
  3547 permits the definition of tail-recursive functions without the
  3548 provision of a termination measure. The latter is necessary once the
  3549 invariant proof rule for while is applied.
  3550 
  3551 * HOL: new (overloaded) notation for the set of elements below/above
  3552 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3553 
  3554 * HOL: theorems impI, allI, ballI bound as "strip";
  3555 
  3556 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3557 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3558 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3559 
  3560 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3561 
  3562 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3563 main HOL, but was unused);
  3564 
  3565 * HOL: fewer consts declared as global (e.g. have to refer to
  3566 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3567 
  3568 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3569 in case of overlap with user translations (e.g. judgements over
  3570 tuples); (note that the underlying logical represenation is still
  3571 bogus);
  3572 
  3573 
  3574 *** ZF ***
  3575 
  3576 * ZF: simplification automatically cancels common terms in arithmetic
  3577 expressions over nat and int;
  3578 
  3579 * ZF: new treatment of nat to minimize type-checking: all operators
  3580 coerce their operands to a natural number using the function natify,
  3581 making the algebraic laws unconditional;
  3582 
  3583 * ZF: as above, for int: operators coerce their operands to an integer
  3584 using the function intify;
  3585 
  3586 * ZF: the integer library now contains many of the usual laws for the
  3587 orderings, including $<=, and monotonicity laws for $+ and $*;
  3588 
  3589 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3590 simplification;
  3591 
  3592 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3593 to the simplifier and classical reasoner simultaneously;
  3594 
  3595 
  3596 *** General ***
  3597 
  3598 * Provers: blast_tac now handles actual object-logic rules as
  3599 assumptions; note that auto_tac uses blast_tac internally as well;
  3600 
  3601 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3602 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3603 
  3604 * Provers: delrules now handles destruct rules as well (no longer need
  3605 explicit make_elim);
  3606 
  3607 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3608   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3609 use instead the strong form,
  3610   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3611 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3612 from destruct-rules;
  3613 
  3614 * Provers: Simplifier.easy_setup provides a fast path to basic
  3615 Simplifier setup for new object-logics;
  3616 
  3617 * Pure: AST translation rules no longer require constant head on LHS;
  3618 
  3619 * Pure: improved name spaces: ambiguous output is qualified; support
  3620 for hiding of names;
  3621 
  3622 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3623 XSYMBOL_HOME; no longer need to do manual configuration in most
  3624 situations;
  3625 
  3626 * system: compression of ML heaps images may now be controlled via -c
  3627 option of isabelle and isatool usedir (currently only observed by
  3628 Poly/ML);
  3629 
  3630 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3631 useful for remote X11);
  3632 
  3633 * system: provide TAGS file for Isabelle sources;
  3634 
  3635 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3636 order;
  3637 
  3638 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3639 timing flag supersedes proof_timing and Toplevel.trace;
  3640 
  3641 * ML: new combinators |>> and |>>> for incremental transformations
  3642 with secondary results (e.g. certain theory extensions):
  3643 
  3644 * ML: PureThy.add_defs gets additional argument to indicate potential
  3645 overloading (usually false);
  3646 
  3647 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3648 results;
  3649 
  3650 
  3651 
  3652 New in Isabelle99 (October 1999)
  3653 --------------------------------
  3654 
  3655 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3656 
  3657 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3658 are no longer simplified.  (This allows the simplifier to unfold recursive
  3659 functional programs.)  To restore the old behaviour, declare
  3660 
  3661     Delcongs [if_weak_cong];
  3662 
  3663 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3664 complement;
  3665 
  3666 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3667 
  3668 * HOL/datatype: mutual_induct_tac no longer exists --
  3669   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3670 
  3671 * HOL/typedef: fixed type inference for representing set; type
  3672 arguments now have to occur explicitly on the rhs as type constraints;
  3673 
  3674 * ZF: The con_defs part of an inductive definition may no longer refer
  3675 to constants declared in the same theory;
  3676 
  3677 * HOL, ZF: the function mk_cases, generated by the inductive
  3678 definition package, has lost an argument.  To simplify its result, it
  3679 uses the default simpset instead of a supplied list of theorems.
  3680 
  3681 * HOL/List: the constructors of type list are now Nil and Cons;
  3682 
  3683 * Simplifier: the type of the infix ML functions
  3684         setSSolver addSSolver setSolver addSolver
  3685 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3686 for packaging solvers. A solver is created via
  3687         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3688 where the string argument is only a comment.
  3689 
  3690 
  3691 *** Proof tools ***
  3692 
  3693 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3694 decision procedure for linear arithmetic. Currently it is used for
  3695 types `nat', `int', and `real' in HOL (see below); it can, should and
  3696 will be instantiated for other types and logics as well.
  3697 
  3698 * The simplifier now accepts rewrite rules with flexible heads, eg
  3699      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3700   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3701   matching.
  3702 
  3703 
  3704 *** General ***
  3705 
  3706 * New Isabelle/Isar subsystem provides an alternative to traditional
  3707 tactical theorem proving; together with the ProofGeneral/isar user
  3708 interface it offers an interactive environment for developing human
  3709 readable proof documents (Isar == Intelligible semi-automated
  3710 reasoning); for further information see isatool doc isar-ref,
  3711 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3712 
  3713 * improved and simplified presentation of theories: better HTML markup
  3714 (including colors), graph views in several sizes; isatool usedir now
  3715 provides a proper interface for user theories (via -P option); actual
  3716 document preparation based on (PDF)LaTeX is available as well (for
  3717 new-style theories only); see isatool doc system for more information;
  3718 
  3719 * native support for Proof General, both for classic Isabelle and
  3720 Isabelle/Isar;
  3721 
  3722 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3723 using the graph browser tool;
  3724 
  3725 * Isabelle manuals now also available as PDF;
  3726 
  3727 * theory loader rewritten from scratch (may not be fully
  3728 bug-compatible); old loadpath variable has been replaced by show_path,
  3729 add_path, del_path, reset_path functions; new operations such as
  3730 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3731 isatool doc ref);
  3732 
  3733 * improved isatool install: option -k creates KDE application icon,
  3734 option -p DIR installs standalone binaries;
  3735 
  3736 * added ML_PLATFORM setting (useful for cross-platform installations);
  3737 more robust handling of platform specific ML images for SML/NJ;
  3738 
  3739 * the settings environment is now statically scoped, i.e. it is never
  3740 created again in sub-processes invoked from isabelle, isatool, or
  3741 Isabelle;
  3742 
  3743 * path element specification '~~' refers to '$ISABELLE_HOME';
  3744 
  3745 * in locales, the "assumes" and "defines" parts may be omitted if
  3746 empty;
  3747 
  3748 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3749 long arrows);
  3750 
  3751 * new print_mode "HTML";
  3752 
  3753 * new flag show_tags controls display of tags of theorems (which are
  3754 basically just comments that may be attached by some tools);
  3755 
  3756 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3757 mode and goal output format:
  3758 
  3759 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3760 244c244
  3761 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3762 ---
  3763 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3764 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3765 181c181
  3766 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3767 ---
  3768 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3769 
  3770 * function bind_thms stores lists of theorems (cf. bind_thm);
  3771 
  3772 * new shorthand tactics ftac, eatac, datac, fatac;
  3773 
  3774 * qed (and friends) now accept "" as result name; in that case the
  3775 theorem is not stored, but proper checks and presentation of the
  3776 result still apply;
  3777 
  3778 * theorem database now also indexes constants "Trueprop", "all",
  3779 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3780 
  3781 
  3782 *** HOL ***
  3783 
  3784 ** HOL arithmetic **
  3785 
  3786 * There are now decision procedures for linear arithmetic over nat and
  3787 int:
  3788 
  3789 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3790 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3791 are treated as atomic; subformulae not involving type `nat' or `int'
  3792 are ignored; quantified subformulae are ignored unless they are
  3793 positive universal or negative existential. The tactic has to be
  3794 invoked by hand and can be a little bit slow. In particular, the
  3795 running time is exponential in the number of occurrences of `min' and
  3796 `max', and `-' on `nat'.
  3797 
  3798 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3799 (negated) (in)equalities among the premises and the conclusion into
  3800 account (i.e. no compound formulae) and does not know about `min' and
  3801 `max', and `-' on `nat'. It is fast and is used automatically by the
  3802 simplifier.
  3803 
  3804 NB: At the moment, these decision procedures do not cope with mixed
  3805 nat/int formulae where the two parts interact, such as `m < n ==>
  3806 int(m) < int(n)'.
  3807 
  3808 * HOL/Numeral provides a generic theory of numerals (encoded
  3809 efficiently as bit strings); setup for types nat/int/real is in place;
  3810 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3811 int, existing theories and proof scripts may require a few additional
  3812 type constraints;
  3813 
  3814 * integer division and remainder can now be performed on constant
  3815 arguments;
  3816 
  3817 * many properties of integer multiplication, division and remainder
  3818 are now available;
  3819 
  3820 * An interface to the Stanford Validity Checker (SVC) is available through the
  3821 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3822 are proved automatically.  SVC must be installed separately, and its results
  3823 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3824 invocation of the underlying oracle).  For SVC see
  3825   http://verify.stanford.edu/SVC
  3826 
  3827 * IsaMakefile: the HOL-Real target now builds an actual image;
  3828 
  3829 
  3830 ** HOL misc **
  3831 
  3832 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3833 (in Isabelle/Isar) -- by Gertrud Bauer;
  3834 
  3835 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3836 analysis for assembly languages with subtypes;
  3837 
  3838 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3839 -- avoids syntactic ambiguities and treats state, transition, and
  3840 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3841 changed syntax and (many) tactics;
  3842 
  3843 * HOL/inductive: Now also handles more general introduction rules such
  3844   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3845   theorems are now maintained within the theory (maintained via the
  3846   "mono" attribute);
  3847 
  3848 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3849   (using function types) such as
  3850 
  3851   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3852 
  3853 * HOL/record: record_simproc (part of the default simpset) takes care
  3854 of selectors applied to updated records; record_split_tac is no longer
  3855 part of the default claset; update_defs may now be removed from the
  3856 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3857 
  3858   claset_ref () := claset() addSWrapper record_split_wrapper;
  3859   Delsimprocs [record_simproc]
  3860 
  3861 * HOL/typedef: fixed type inference for representing set; type
  3862 arguments now have to occur explicitly on the rhs as type constraints;
  3863 
  3864 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3865 names rather than an ML expression;
  3866 
  3867 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3868 supplied later.  Program schemes can be defined, such as
  3869     "While B C s = (if B s then While B C (C s) else s)"
  3870 where the well-founded relation can be chosen after B and C have been given.
  3871 
  3872 * HOL/List: the constructors of type list are now Nil and Cons;
  3873 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3874 course, ML tools referring to List.list.op # etc. have to be adapted;
  3875 
  3876 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3877 disabled by default; run isabelle with option -m HOL to get back to
  3878 the original Gordon/HOL-style output;
  3879 
  3880 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3881 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3882 
  3883 * HOL basic syntax simplified (more orthogonal): all variants of
  3884 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3885 Eps operator is provided as well: "SOME x. P[x]";
  3886 
  3887 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3888 
  3889 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3890 thus available for user theories;
  3891 
  3892 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3893 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3894 time;
  3895 
  3896 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3897 several times and then mp;
  3898 
  3899 
  3900 *** LK ***
  3901 
  3902 * the notation <<...>> is now available as a notation for sequences of
  3903 formulas;
  3904 
  3905 * the simplifier is now installed
  3906 
  3907 * the axiom system has been generalized (thanks to Soren Heilmann)
  3908 
  3909 * the classical reasoner now has a default rule database
  3910 
  3911 
  3912 *** ZF ***
  3913 
  3914 * new primrec section allows primitive recursive functions to be given
  3915 directly (as in HOL) over datatypes and the natural numbers;
  3916 
  3917 * new tactics induct_tac and exhaust_tac for induction (or case
  3918 analysis) over datatypes and the natural numbers;
  3919 
  3920 * the datatype declaration of type T now defines the recursor T_rec;
  3921 
  3922 * simplification automatically does freeness reasoning for datatype
  3923 constructors;
  3924 
  3925 * automatic type-inference, with AddTCs command to insert new
  3926 type-checking rules;
  3927 
  3928 * datatype introduction rules are now added as Safe Introduction rules
  3929 to the claset;
  3930 
  3931 * the syntax "if P then x else y" is now available in addition to
  3932 if(P,x,y);
  3933 
  3934 
  3935 *** Internal programming interfaces ***
  3936 
  3937 * tuned simplifier trace output; new flag debug_simp;
  3938 
  3939 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3940 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3941 
  3942 * AxClass.axclass_tac lost the theory argument;
  3943 
  3944 * tuned current_goals_markers semantics: begin / end goal avoids
  3945 printing empty lines;
  3946 
  3947 * removed prs and prs_fn hook, which was broken because it did not
  3948 include \n in its semantics, forcing writeln to add one
  3949 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3950 string -> unit if you really want to output text without newline;
  3951 
  3952 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3953 plain output, interface builders may have to enable 'isabelle_font'
  3954 mode to get Isabelle font glyphs as before;
  3955 
  3956 * refined token_translation interface; INCOMPATIBILITY: output length
  3957 now of type real instead of int;
  3958 
  3959 * theory loader actions may be traced via new ThyInfo.add_hook
  3960 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3961 your own database of information attached to *whole* theories -- as
  3962 opposed to intra-theory data slots offered via TheoryDataFun;
  3963 
  3964 * proper handling of dangling sort hypotheses (at last!);
  3965 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3966 extra sort hypotheses that can be witnessed from the type signature;
  3967 the force_strip_shyps flag is gone, any remaining shyps are simply
  3968 left in the theorem (with a warning issued by strip_shyps_warning);
  3969 
  3970 
  3971 
  3972 New in Isabelle98-1 (October 1998)
  3973 ----------------------------------
  3974 
  3975 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3976 
  3977 * several changes of automated proof tools;
  3978 
  3979 * HOL: major changes to the inductive and datatype packages, including
  3980 some minor incompatibilities of theory syntax;
  3981 
  3982 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3983 called `inj_on';
  3984 
  3985 * HOL: removed duplicate thms in Arith:
  3986   less_imp_add_less  should be replaced by  trans_less_add1
  3987   le_imp_add_le      should be replaced by  trans_le_add1
  3988 
  3989 * HOL: unary minus is now overloaded (new type constraints may be
  3990 required);
  3991 
  3992 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3993 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3994 now taken as an integer constant.
  3995 
  3996 * Pure: ML function 'theory_of' renamed to 'theory';
  3997 
  3998 
  3999 *** Proof tools ***
  4000 
  4001 * Simplifier:
  4002   1. Asm_full_simp_tac is now more aggressive.
  4003      1. It will sometimes reorient premises if that increases their power to
  4004         simplify.
  4005      2. It does no longer proceed strictly from left to right but may also
  4006         rotate premises to achieve further simplification.
  4007      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4008      old Asm_full_simp_tac in that it does not rotate premises.
  4009   2. The simplifier now knows a little bit about nat-arithmetic.
  4010 
  4011 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4012 allows for selected deletion of wrappers, by introduction of names for
  4013 wrapper functionals.  This implies that addbefore, addSbefore,
  4014 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4015 and that adding two tactics with the same name overwrites the first
  4016 one (emitting a warning).
  4017   type wrapper = (int -> tactic) -> (int -> tactic)
  4018   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4019   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4020   delWrapper, delSWrapper: claset *  string            -> claset
  4021   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4022 
  4023 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4024 semantics; addbefore now affects only the unsafe part of step_tac
  4025 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4026 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4027 by Force_tac;
  4028 
  4029 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4030 compWrapper; added safe wrapper (and access functions for it);
  4031 
  4032 * HOL/split_all_tac is now much faster and fails if there is nothing
  4033 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4034 and the names of the automatically generated variables have changed.
  4035 split_all_tac has moved within claset() from unsafe wrappers to safe
  4036 wrappers, which means that !!-bound variables are split much more
  4037 aggressively, and safe_tac and clarify_tac now split such variables.
  4038 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4039 Note: the same holds for record_split_tac, which does the job of
  4040 split_all_tac for record fields.
  4041 
  4042 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4043 permanently to the default simpset using Addsplits just like
  4044 Addsimps. They can be removed via Delsplits just like
  4045 Delsimps. Lower-case versions are also available.
  4046 
  4047 * HOL/Simplifier: The rule split_if is now part of the default
  4048 simpset. This means that the simplifier will eliminate all occurrences
  4049 of if-then-else in the conclusion of a goal. To prevent this, you can
  4050 either remove split_if completely from the default simpset by
  4051 `Delsplits [split_if]' or remove it in a specific call of the
  4052 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4053 other case splitting rules to/from the default simpset: every datatype
  4054 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4055 t is the name of the datatype).
  4056 
  4057 * Classical reasoner / Simplifier combination: new force_tac (and
  4058 derivatives Force_tac, force) combines rewriting and classical
  4059 reasoning (and whatever other tools) similarly to auto_tac, but is
  4060 aimed to solve the given subgoal completely.
  4061 
  4062 
  4063 *** General ***
  4064 
  4065 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4066 and `goalw': the theory is no longer needed as an explicit argument -
  4067 the current theory context is used; assumptions are no longer returned
  4068 at the ML-level unless one of them starts with ==> or !!; it is
  4069 recommended to convert to these new commands using isatool fixgoal
  4070 (backup your sources first!);
  4071 
  4072 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4073 the current theory context, and 'theory' to lookup stored theories;
  4074 
  4075 * new theory section 'locale' for declaring constants, assumptions and
  4076 definitions that have local scope;
  4077 
  4078 * new theory section 'nonterminals' for purely syntactic types;
  4079 
  4080 * new theory section 'setup' for generic ML setup functions
  4081 (e.g. package initialization);
  4082 
  4083 * the distribution now includes Isabelle icons: see
  4084 lib/logo/isabelle-{small,tiny}.xpm;
  4085 
  4086 * isatool install - install binaries with absolute references to
  4087 ISABELLE_HOME/bin;
  4088 
  4089 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4090 
  4091 * print mode 'emacs' reserved for Isamode;
  4092 
  4093 * support multiple print (ast) translations per constant name;
  4094 
  4095 * theorems involving oracles are now printed with a suffixed [!];
  4096 
  4097 
  4098 *** HOL ***
  4099 
  4100 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4101 
  4102 * HOL/inductive package reorganized and improved: now supports mutual
  4103 definitions such as
  4104 
  4105   inductive EVEN ODD
  4106     intrs
  4107       null "0 : EVEN"
  4108       oddI "n : EVEN ==> Suc n : ODD"
  4109       evenI "n : ODD ==> Suc n : EVEN"
  4110 
  4111 new theorem list "elims" contains an elimination rule for each of the
  4112 recursive sets; inductive definitions now handle disjunctive premises
  4113 correctly (also ZF);
  4114 
  4115 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4116 "mutual_induct" no longer exists - the induction rule is always
  4117 contained in "induct";
  4118 
  4119 
  4120 * HOL/datatype package re-implemented and greatly improved: now
  4121 supports mutually recursive datatypes such as
  4122 
  4123   datatype
  4124     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4125             | SUM ('a aexp) ('a aexp)
  4126             | DIFF ('a aexp) ('a aexp)
  4127             | NUM 'a
  4128   and
  4129     'a bexp = LESS ('a aexp) ('a aexp)
  4130             | AND ('a bexp) ('a bexp)
  4131             | OR ('a bexp) ('a bexp)
  4132 
  4133 as well as indirectly recursive datatypes such as
  4134 
  4135   datatype
  4136     ('a, 'b) term = Var 'a
  4137                   | App 'b ((('a, 'b) term) list)
  4138 
  4139 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4140 induction on mutually / indirectly recursive datatypes.
  4141 
  4142 Primrec equations are now stored in theory and can be accessed via
  4143 <function_name>.simps.
  4144 
  4145 INCOMPATIBILITIES:
  4146 
  4147   - Theories using datatypes must now have theory Datatype as an
  4148     ancestor.
  4149   - The specific <typename>.induct_tac no longer exists - use the
  4150     generic induct_tac instead.
  4151   - natE has been renamed to nat.exhaust - use exhaust_tac
  4152     instead of res_inst_tac ... natE. Note that the variable
  4153     names in nat.exhaust differ from the names in natE, this
  4154     may cause some "fragile" proofs to fail.
  4155   - The theorems split_<typename>_case and split_<typename>_case_asm
  4156     have been renamed to <typename>.split and <typename>.split_asm.
  4157   - Since default sorts of type variables are now handled correctly,
  4158     some datatype definitions may have to be annotated with explicit
  4159     sort constraints.
  4160   - Primrec definitions no longer require function name and type
  4161     of recursive argument.
  4162 
  4163 Consider using isatool fixdatatype to adapt your theories and proof
  4164 scripts to the new package (backup your sources first!).
  4165 
  4166 
  4167 * HOL/record package: considerably improved implementation; now
  4168 includes concrete syntax for record types, terms, updates; theorems
  4169 for surjective pairing and splitting !!-bound record variables; proof
  4170 support is as follows:
  4171 
  4172   1) standard conversions (selectors or updates applied to record
  4173 constructor terms) are part of the standard simpset;
  4174 
  4175   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4176 made part of standard simpset and claset via addIffs;
  4177 
  4178   3) a tactic for record field splitting (record_split_tac) is part of
  4179 the standard claset (addSWrapper);
  4180 
  4181 To get a better idea about these rules you may retrieve them via
  4182 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4183 the name of your record type.
  4184 
  4185 The split tactic 3) conceptually simplifies by the following rule:
  4186 
  4187   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4188 
  4189 Thus any record variable that is bound by meta-all will automatically
  4190 blow up into some record constructor term, consequently the
  4191 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4192 solve record problems automatically.
  4193 
  4194 
  4195 * reorganized the main HOL image: HOL/Integ and String loaded by
  4196 default; theory Main includes everything;
  4197 
  4198 * automatic simplification of integer sums and comparisons, using cancellation;
  4199 
  4200 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4201 
  4202 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4203 
  4204 * many new identities for unions, intersections, set difference, etc.;
  4205 
  4206 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4207 called split_if, split_split, split_sum_case and split_nat_case (to go
  4208 with add/delsplits);
  4209 
  4210 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4211 (?x::unit) = (); this is made part of the default simpset, which COULD
  4212 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4213 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4214 unit_abs_eta_conv is added in order to counter the effect of
  4215 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4216 %u.f();
  4217 
  4218 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4219 makes more sense);
  4220 
  4221 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4222   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4223   disjointness reasoning but breaking a few old proofs.
  4224 
  4225 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4226 to 'converse' from 'inverse' (for compatibility with ZF and some
  4227 literature);
  4228 
  4229 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4230 the well-founded relation;
  4231 
  4232 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4233     Compl A.  The "Compl" syntax remains available as input syntax for this
  4234     release ONLY.
  4235 
  4236 * HOL/Update: new theory of function updates:
  4237     f(a:=b) == %x. if x=a then b else f x
  4238 may also be iterated as in f(a:=b,c:=d,...);
  4239 
  4240 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4241 
  4242 * HOL/List:
  4243   - new function list_update written xs[i:=v] that updates the i-th
  4244     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4245   - new function `upt' written [i..j(] which generates the list
  4246     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4247     bound write [i..j], which is a shorthand for [i..j+1(].
  4248   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4249 
  4250 * HOL/Arith:
  4251   - removed 'pred' (predecessor) function;
  4252   - generalized some theorems about n-1;
  4253   - many new laws about "div" and "mod";
  4254   - new laws about greatest common divisors (see theory ex/Primes);
  4255 
  4256 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4257 instead of "inverse";
  4258 
  4259 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4260   of the multiset ordering;
  4261 
  4262 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4263   (not included by default);
  4264 
  4265 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4266 
  4267 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4268   programs, i.e. different program variables may have different types.
  4269 
  4270 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4271   [previously, this check worked only if the rewrite rule was unconditional]
  4272   Now rew can involve either definitions or equalities (either == or =).
  4273 
  4274 
  4275 *** ZF ***
  4276 
  4277 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4278   only the theorems proved on ZF.ML;
  4279 
  4280 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4281   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4282   disjointness reasoning but breaking a few old proofs.
  4283 
  4284 * ZF/Update: new theory of function updates
  4285     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4286   may also be iterated as in f(a:=b,c:=d,...);
  4287 
  4288 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4289 
  4290 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4291   [previously, this check worked only if the rewrite rule was unconditional]
  4292   Now rew can involve either definitions or equalities (either == or =).
  4293 
  4294 * case_tac provided for compatibility with HOL
  4295     (like the old excluded_middle_tac, but with subgoals swapped)
  4296 
  4297 
  4298 *** Internal programming interfaces ***
  4299 
  4300 * Pure: several new basic modules made available for general use, see
  4301 also src/Pure/README;
  4302 
  4303 * improved the theory data mechanism to support encapsulation (data
  4304 kind name replaced by private Object.kind, acting as authorization
  4305 key); new type-safe user interface via functor TheoryDataFun; generic
  4306 print_data function becomes basically useless;
  4307 
  4308 * removed global_names compatibility flag -- all theory declarations
  4309 are qualified by default;
  4310 
  4311 * module Pure/Syntax now offers quote / antiquote translation
  4312 functions (useful for Hoare logic etc. with implicit dependencies);
  4313 see HOL/ex/Antiquote for an example use;
  4314 
  4315 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4316 cterm -> thm;
  4317 
  4318 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4319 subgoal;
  4320 
  4321 * Display.print_goals function moved to Locale.print_goals;
  4322 
  4323 * standard print function for goals supports current_goals_markers
  4324 variable for marking begin of proof, end of proof, start of goal; the
  4325 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4326 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4327 for example;
  4328 
  4329 
  4330 
  4331 New in Isabelle98 (January 1998)
  4332 --------------------------------
  4333 
  4334 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4335 
  4336 * changed lexical syntax of terms / types: dots made part of long
  4337 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4338 
  4339 * simpset (and claset) reference variable replaced by functions
  4340 simpset / simpset_ref;
  4341 
  4342 * no longer supports theory aliases (via merge) and non-trivial
  4343 implicit merge of thms' signatures;
  4344 
  4345 * most internal names of constants changed due to qualified names;
  4346 
  4347 * changed Pure/Sequence interface (see Pure/seq.ML);
  4348 
  4349 
  4350 *** General Changes ***
  4351 
  4352 * hierachically structured name spaces (for consts, types, axms, thms
  4353 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4354 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4355 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4356 long_names for fully qualified output names; NOTE: ML programs
  4357 (special tactics, packages etc.) referring to internal names may have
  4358 to be adapted to cope with fully qualified names; in case of severe
  4359 backward campatibility problems try setting 'global_names' at compile
  4360 time to have enrything declared within a flat name space; one may also
  4361 fine tune name declarations in theories via the 'global' and 'local'
  4362 section;
  4363 
  4364 * reimplemented the implicit simpset and claset using the new anytype
  4365 data filed in signatures; references simpset:simpset ref etc. are
  4366 replaced by functions simpset:unit->simpset and
  4367 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4368 to patch your ML files accordingly;
  4369 
  4370 * HTML output now includes theory graph data for display with Java
  4371 applet or isatool browser; data generated automatically via isatool
  4372 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4373 
  4374 * defs may now be conditional; improved rewrite_goals_tac to handle
  4375 conditional equations;
  4376 
  4377 * defs now admits additional type arguments, using TYPE('a) syntax;
  4378 
  4379 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4380 creates a new theory node; implicit merge of thms' signatures is
  4381 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4382 transfer:theory->thm->thm in (rare) cases;
  4383 
  4384 * improved handling of draft signatures / theories; draft thms (and
  4385 ctyps, cterms) are automatically promoted to real ones;
  4386 
  4387 * slightly changed interfaces for oracles: admit many per theory, named
  4388 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4389 
  4390 * print_goals: optional output of const types (set show_consts and
  4391 show_types);
  4392 
  4393 * improved output of warnings (###) and errors (***);
  4394 
  4395 * subgoal_tac displays a warning if the new subgoal has type variables;
  4396 
  4397 * removed old README and Makefiles;
  4398 
  4399 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4400 
  4401 * removed obsolete init_pps and init_database;
  4402 
  4403 * deleted the obsolete tactical STATE, which was declared by
  4404     fun STATE tacfun st = tacfun st st;
  4405 
  4406 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4407 (which abbreviates $HOME);
  4408 
  4409 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4410 use isatool fixseq to adapt your ML programs (this works for fully
  4411 qualified references to the Sequence structure only!);
  4412 
  4413 * use_thy no longer requires writable current directory; it always
  4414 reloads .ML *and* .thy file, if either one is out of date;
  4415 
  4416 
  4417 *** Classical Reasoner ***
  4418 
  4419 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4420 tactics that use classical reasoning to simplify a subgoal without
  4421 splitting it into several subgoals;
  4422 
  4423 * Safe_tac: like safe_tac but uses the default claset;
  4424 
  4425 
  4426 *** Simplifier ***
  4427 
  4428 * added simplification meta rules:
  4429     (asm_)(full_)simplify: simpset -> thm -> thm;
  4430 
  4431 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4432 logics (again);
  4433 
  4434 * added prems argument to simplification procedures;
  4435 
  4436 * HOL, FOL, ZF: added infix function `addsplits':
  4437   instead of `<simpset> setloop (split_tac <thms>)'
  4438   you can simply write `<simpset> addsplits <thms>'
  4439 
  4440 
  4441 *** Syntax ***
  4442 
  4443 * TYPE('a) syntax for type reflection terms;
  4444 
  4445 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4446 
  4447 * pretty printer: changed order of mixfix annotation preference (again!);
  4448 
  4449 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4450 
  4451 
  4452 *** HOL ***
  4453 
  4454 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4455   with `addloop' of the simplifier to faciliate case splitting in premises.
  4456 
  4457 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4458 
  4459 * HOL/Auth: new protocol proofs including some for the Internet
  4460   protocol TLS;
  4461 
  4462 * HOL/Map: new theory of `maps' a la VDM;
  4463 
  4464 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4465 cancelling out common nat summands from =, <, <= (in)equalities, or
  4466 differences; simplification procedures nat_cancel_factor for
  4467 cancelling common factor from =, <, <= (in)equalities over natural
  4468 sums; nat_cancel contains both kinds of procedures, it is installed by
  4469 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4470 
  4471 * HOL/simplifier: terms of the form
  4472   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4473   are rewritten to
  4474   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4475   and those of the form
  4476   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4477   are rewritten to
  4478   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4479 
  4480 * HOL/datatype
  4481   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4482 
  4483   P(t_case f1 ... fn x) =
  4484      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4485         ...
  4486        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4487      )
  4488 
  4489   and a theorem `split_t_case_asm' of the form
  4490 
  4491   P(t_case f1 ... fn x) =
  4492     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4493         ...
  4494        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4495      )
  4496   which can be added to a simpset via `addsplits'. The existing theorems
  4497   expand_list_case and expand_option_case have been renamed to
  4498   split_list_case and split_option_case.
  4499 
  4500 * HOL/Arithmetic:
  4501   - `pred n' is automatically converted to `n-1'.
  4502     Users are strongly encouraged not to use `pred' any longer,
  4503     because it will disappear altogether at some point.
  4504   - Users are strongly encouraged to write "0 < n" rather than
  4505     "n ~= 0". Theorems and proof tools have been modified towards this
  4506     `standard'.
  4507 
  4508 * HOL/Lists:
  4509   the function "set_of_list" has been renamed "set" (and its theorems too);
  4510   the function "nth" now takes its arguments in the reverse order and
  4511   has acquired the infix notation "!" as in "xs!n".
  4512 
  4513 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4514 
  4515 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4516   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4517 
  4518 * HOL/record: extensible records with schematic structural subtyping
  4519 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4520 still lacks various theorems and concrete record syntax;
  4521 
  4522 
  4523 *** HOLCF ***
  4524 
  4525 * removed "axioms" and "generated by" sections;
  4526 
  4527 * replaced "ops" section by extended "consts" section, which is capable of
  4528   handling the continuous function space "->" directly;
  4529 
  4530 * domain package:
  4531   . proves theorems immediately and stores them in the theory,
  4532   . creates hierachical name space,
  4533   . now uses normal mixfix annotations (instead of cinfix...),
  4534   . minor changes to some names and values (for consistency),
  4535   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4536   . separator between mutual domain defs: changed "," to "and",
  4537   . improved handling of sort constraints;  now they have to
  4538     appear on the left-hand side of the equations only;
  4539 
  4540 * fixed LAM <x,y,zs>.b syntax;
  4541 
  4542 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4543 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4544 
  4545 
  4546 *** FOL and ZF ***
  4547 
  4548 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4549   with `addloop' of the simplifier to faciliate case splitting in premises.
  4550 
  4551 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4552 in HOL, they strip ALL and --> from proved theorems;
  4553 
  4554 
  4555 
  4556 New in Isabelle94-8 (May 1997)
  4557 ------------------------------
  4558 
  4559 *** General Changes ***
  4560 
  4561 * new utilities to build / run / maintain Isabelle etc. (in parts
  4562 still somewhat experimental); old Makefiles etc. still functional;
  4563 
  4564 * new 'Isabelle System Manual';
  4565 
  4566 * INSTALL text, together with ./configure and ./build scripts;
  4567 
  4568 * reimplemented type inference for greater efficiency, better error
  4569 messages and clean internal interface;
  4570 
  4571 * prlim command for dealing with lots of subgoals (an easier way of
  4572 setting goals_limit);
  4573 
  4574 
  4575 *** Syntax ***
  4576 
  4577 * supports alternative (named) syntax tables (parser and pretty
  4578 printer); internal interface is provided by add_modesyntax(_i);
  4579 
  4580 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4581 be used in conjunction with the Isabelle symbol font; uses the
  4582 "symbols" syntax table;
  4583 
  4584 * added token_translation interface (may translate name tokens in
  4585 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4586 the current print_mode); IMPORTANT: user print translation functions
  4587 are responsible for marking newly introduced bounds
  4588 (Syntax.mark_boundT);
  4589 
  4590 * token translations for modes "xterm" and "xterm_color" that display
  4591 names in bold, underline etc. or colors (which requires a color
  4592 version of xterm);
  4593 
  4594 * infixes may now be declared with names independent of their syntax;
  4595 
  4596 * added typed_print_translation (like print_translation, but may
  4597 access type of constant);
  4598 
  4599 
  4600 *** Classical Reasoner ***
  4601 
  4602 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4603 some limitations.  Blast_tac...
  4604   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4605   + ignores elimination rules that don't have the correct format
  4606         (the conclusion MUST be a formula variable)
  4607   + ignores types, which can make HOL proofs fail
  4608   + rules must not require higher-order unification, e.g. apply_type in ZF
  4609     [message "Function Var's argument not a bound variable" relates to this]
  4610   + its proof strategy is more general but can actually be slower
  4611 
  4612 * substitution with equality assumptions no longer permutes other
  4613 assumptions;
  4614 
  4615 * minor changes in semantics of addafter (now called addaltern); renamed
  4616 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4617 (and access functions for it);
  4618 
  4619 * improved combination of classical reasoner and simplifier:
  4620   + functions for handling clasimpsets
  4621   + improvement of addss: now the simplifier is called _after_ the
  4622     safe steps.
  4623   + safe variant of addss called addSss: uses safe simplifications
  4624     _during_ the safe steps. It is more complete as it allows multiple
  4625     instantiations of unknowns (e.g. with slow_tac).
  4626 
  4627 *** Simplifier ***
  4628 
  4629 * added interface for simplification procedures (functions that
  4630 produce *proven* rewrite rules on the fly, depending on current
  4631 redex);
  4632 
  4633 * ordering on terms as parameter (used for ordered rewriting);
  4634 
  4635 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4636 
  4637 * the solver is now split into a safe and an unsafe part.
  4638 This should be invisible for the normal user, except that the
  4639 functions setsolver and addsolver have been renamed to setSolver and
  4640 addSolver; added safe_asm_full_simp_tac;
  4641 
  4642 
  4643 *** HOL ***
  4644 
  4645 * a generic induction tactic `induct_tac' which works for all datatypes and
  4646 also for type `nat';
  4647 
  4648 * a generic case distinction tactic `exhaust_tac' which works for all
  4649 datatypes and also for type `nat';
  4650 
  4651 * each datatype comes with a function `size';
  4652 
  4653 * patterns in case expressions allow tuple patterns as arguments to
  4654 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4655 
  4656 * primrec now also works with type nat;
  4657 
  4658 * recdef: a new declaration form, allows general recursive functions to be
  4659 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4660 
  4661 * the constant for negation has been renamed from "not" to "Not" to
  4662 harmonize with FOL, ZF, LK, etc.;
  4663 
  4664 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4665 infinite lists;
  4666 
  4667 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4668 
  4669 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4670 problems in commutative rings, using axiomatic type classes for + and *;
  4671 
  4672 * more examples in HOL/MiniML and HOL/Auth;
  4673 
  4674 * more default rewrite rules for quantifiers, union/intersection;
  4675 
  4676 * a new constant `arbitrary == @x.False';
  4677 
  4678 * HOLCF/IOA replaces old HOL/IOA;
  4679 
  4680 * HOLCF changes: derived all rules and arities
  4681   + axiomatic type classes instead of classes
  4682   + typedef instead of faking type definitions
  4683   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4684   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4685   + eliminated the types void, one, tr
  4686   + use unit lift and bool lift (with translations) instead of one and tr
  4687   + eliminated blift from Lift3.thy (use Def instead of blift)
  4688   all eliminated rules are derived as theorems --> no visible changes ;
  4689 
  4690 
  4691 *** ZF ***
  4692 
  4693 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4694 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4695 as ZF_cs addSIs [equalityI];
  4696 
  4697 
  4698 
  4699 New in Isabelle94-7 (November 96)
  4700 ---------------------------------
  4701 
  4702 * allowing negative levels (as offsets) in prlev and choplev;
  4703 
  4704 * super-linear speedup for large simplifications;
  4705 
  4706 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4707 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4708 FAIL); can suppress it using the command Delsimps (ex_simps @
  4709 all_simps); De Morgan laws are also now included, by default;
  4710 
  4711 * improved printing of ==>  :  ~:
  4712 
  4713 * new object-logic "Sequents" adds linear logic, while replacing LK
  4714 and Modal (thanks to Sara Kalvala);
  4715 
  4716 * HOL/Auth: correctness proofs for authentication protocols;
  4717 
  4718 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4719 examples on HOL/Auth);
  4720 
  4721 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4722 the rewriter and classical reasoner simultaneously;
  4723 
  4724 * function uresult no longer returns theorems in "standard" format;
  4725 regain previous version by: val uresult = standard o uresult;
  4726 
  4727 
  4728 
  4729 New in Isabelle94-6
  4730 -------------------
  4731 
  4732 * oracles -- these establish an interface between Isabelle and trusted
  4733 external reasoners, which may deliver results as theorems;
  4734 
  4735 * proof objects (in particular record all uses of oracles);
  4736 
  4737 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4738 
  4739 * "constdefs" section in theory files;
  4740 
  4741 * "primrec" section (HOL) no longer requires names;
  4742 
  4743 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4744 
  4745 
  4746 
  4747 New in Isabelle94-5
  4748 -------------------
  4749 
  4750 * reduced space requirements;
  4751 
  4752 * automatic HTML generation from theories;
  4753 
  4754 * theory files no longer require "..." (quotes) around most types;
  4755 
  4756 * new examples, including two proofs of the Church-Rosser theorem;
  4757 
  4758 * non-curried (1994) version of HOL is no longer distributed;
  4759 
  4760 
  4761 
  4762 New in Isabelle94-4
  4763 -------------------
  4764 
  4765 * greatly reduced space requirements;
  4766 
  4767 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4768 
  4769 * searchable theorem database (see the section "Retrieving theorems" on
  4770 page 8 of the Reference Manual);
  4771 
  4772 * new examples, including Grabczewski's monumental case study of the
  4773 Axiom of Choice;
  4774 
  4775 * The previous version of HOL renamed to Old_HOL;
  4776 
  4777 * The new version of HOL (previously called CHOL) uses a curried syntax
  4778 for functions.  Application looks like f a b instead of f(a,b);
  4779 
  4780 * Mutually recursive inductive definitions finally work in HOL;
  4781 
  4782 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4783 translates to the operator "split";
  4784 
  4785 
  4786 
  4787 New in Isabelle94-3
  4788 -------------------
  4789 
  4790 * new infix operator, addss, allowing the classical reasoner to
  4791 perform simplification at each step of its search.  Example:
  4792         fast_tac (cs addss ss)
  4793 
  4794 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4795 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4796 look like (a,b) instead of <a,b>;
  4797 
  4798 * PLEASE NOTE: CHOL will eventually replace HOL!
  4799 
  4800 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4801 It translates to the operator "split".  A new theory of integers is available;
  4802 
  4803 * In ZF, integer numerals now denote two's-complement binary integers.
  4804 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4805 
  4806 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4807 of the Axiom of Choice;
  4808 
  4809 
  4810 
  4811 New in Isabelle94-2
  4812 -------------------
  4813 
  4814 * Significantly faster resolution;
  4815 
  4816 * the different sections in a .thy file can now be mixed and repeated
  4817 freely;
  4818 
  4819 * Database of theorems for FOL, HOL and ZF.  New
  4820 commands including qed, qed_goal and bind_thm store theorems in the database.
  4821 
  4822 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4823 a given theory (thms_of), or find out what theory a theorem was proved in
  4824 (theory_of_thm);
  4825 
  4826 * Bugs fixed in the inductive definition and datatype packages;
  4827 
  4828 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4829 and HOL_dup_cs obsolete;
  4830 
  4831 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4832 have been removed;
  4833 
  4834 * Simpler definition of function space in ZF;
  4835 
  4836 * new results about cardinal and ordinal arithmetic in ZF;
  4837 
  4838 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4839 types;
  4840 
  4841 
  4842 $Id$