NEWS
author nipkow
Sun Jun 24 10:33:49 2007 +0200 (2007-06-24)
changeset 23478 26a5ef187e8b
parent 23468 d27d79a47592
child 23480 8d01ccdc3652
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 * The lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   607   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   608 
   609 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   610     when generating code.
   611 
   612 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   613     when generating code.
   614 
   615 * Library/Commutative_Ring.thy: switched from recdef to function package;
   616     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   617 
   618 * Some steps towards more uniform lattice theory development in HOL.
   619 
   620     constants "meet" and "join" now named "inf" and "sup"
   621     constant "Meet" now named "Inf"
   622 
   623     classes "meet_semilorder" and "join_semilorder" now named
   624       "lower_semilattice" and "upper_semilattice"
   625     class "lorder" now named "lattice"
   626     class "comp_lat" now named "complete_lattice"
   627 
   628     Instantiation of lattice classes allows explicit definitions
   629     for "inf" and "sup" operations.
   630 
   631   INCOMPATIBILITY.  Theorem renames:
   632 
   633     meet_left_le            ~> inf_le1
   634     meet_right_le           ~> inf_le2
   635     join_left_le            ~> sup_ge1
   636     join_right_le           ~> sup_ge2
   637     meet_join_le            ~> inf_sup_ord
   638     le_meetI                ~> le_infI
   639     join_leI                ~> le_supI
   640     le_meet                 ~> le_inf_iff
   641     le_join                 ~> ge_sup_conv
   642     meet_idempotent         ~> inf_idem
   643     join_idempotent         ~> sup_idem
   644     meet_comm               ~> inf_commute
   645     join_comm               ~> sup_commute
   646     meet_leI1               ~> le_infI1
   647     meet_leI2               ~> le_infI2
   648     le_joinI1               ~> le_supI1
   649     le_joinI2               ~> le_supI2
   650     meet_assoc              ~> inf_assoc
   651     join_assoc              ~> sup_assoc
   652     meet_left_comm          ~> inf_left_commute
   653     meet_left_idempotent    ~> inf_left_idem
   654     join_left_comm          ~> sup_left_commute
   655     join_left_idempotent    ~> sup_left_idem
   656     meet_aci                ~> inf_aci
   657     join_aci                ~> sup_aci
   658     le_def_meet             ~> le_iff_inf
   659     le_def_join             ~> le_iff_sup
   660     join_absorp2            ~> sup_absorb2
   661     join_absorp1            ~> sup_absorb1
   662     meet_absorp1            ~> inf_absorb1
   663     meet_absorp2            ~> inf_absorb2
   664     meet_join_absorp        ~> inf_sup_absorb
   665     join_meet_absorp        ~> sup_inf_absorb
   666     distrib_join_le         ~> distrib_sup_le
   667     distrib_meet_le         ~> distrib_inf_le
   668 
   669     add_meet_distrib_left   ~> add_inf_distrib_left
   670     add_join_distrib_left   ~> add_sup_distrib_left
   671     is_join_neg_meet        ~> is_join_neg_inf
   672     is_meet_neg_join        ~> is_meet_neg_sup
   673     add_meet_distrib_right  ~> add_inf_distrib_right
   674     add_join_distrib_right  ~> add_sup_distrib_right
   675     add_meet_join_distribs  ~> add_sup_inf_distribs
   676     join_eq_neg_meet        ~> sup_eq_neg_inf
   677     meet_eq_neg_join        ~> inf_eq_neg_sup
   678     add_eq_meet_join        ~> add_eq_inf_sup
   679     meet_0_imp_0            ~> inf_0_imp_0
   680     join_0_imp_0            ~> sup_0_imp_0
   681     meet_0_eq_0             ~> inf_0_eq_0
   682     join_0_eq_0             ~> sup_0_eq_0
   683     neg_meet_eq_join        ~> neg_inf_eq_sup
   684     neg_join_eq_meet        ~> neg_sup_eq_inf
   685     join_eq_if              ~> sup_eq_if
   686 
   687     mono_meet               ~> mono_inf
   688     mono_join               ~> mono_sup
   689     meet_bool_eq            ~> inf_bool_eq
   690     join_bool_eq            ~> sup_bool_eq
   691     meet_fun_eq             ~> inf_fun_eq
   692     join_fun_eq             ~> sup_fun_eq
   693     meet_set_eq             ~> inf_set_eq
   694     join_set_eq             ~> sup_set_eq
   695     meet1_iff               ~> inf1_iff
   696     meet2_iff               ~> inf2_iff
   697     meet1I                  ~> inf1I
   698     meet2I                  ~> inf2I
   699     meet1D1                 ~> inf1D1
   700     meet2D1                 ~> inf2D1
   701     meet1D2                 ~> inf1D2
   702     meet2D2                 ~> inf2D2
   703     meet1E                  ~> inf1E
   704     meet2E                  ~> inf2E
   705     join1_iff               ~> sup1_iff
   706     join2_iff               ~> sup2_iff
   707     join1I1                 ~> sup1I1
   708     join2I1                 ~> sup2I1
   709     join1I1                 ~> sup1I1
   710     join2I2                 ~> sup1I2
   711     join1CI                 ~> sup1CI
   712     join2CI                 ~> sup2CI
   713     join1E                  ~> sup1E
   714     join2E                  ~> sup2E
   715 
   716     is_meet_Meet            ~> is_meet_Inf
   717     Meet_bool_def           ~> Inf_bool_def
   718     Meet_fun_def            ~> Inf_fun_def
   719     Meet_greatest           ~> Inf_greatest
   720     Meet_lower              ~> Inf_lower
   721     Meet_set_def            ~> Inf_set_def
   722 
   723     listsp_meetI            ~> listsp_infI
   724     listsp_meet_eq          ~> listsp_inf_eq
   725 
   726     meet_min                ~> inf_min
   727     join_max                ~> sup_max
   728 
   729 * Classes "order" and "linorder": facts "refl", "trans" and
   730 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   731 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   732 
   733 * Classes "order" and "linorder": 
   734 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   735 proofs changed.
   736 
   737 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   738 INCOMPATIBILITY.
   739 
   740 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   741 INCOMPATIBILITY.
   742 
   743 * Added syntactic class "size"; overloaded constant "size" now has
   744 type "'a::size ==> bool"
   745 
   746 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   747 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   748 
   749 * Added method "lexicographic_order" automatically synthesizes
   750 termination relations as lexicographic combinations of size measures
   751 -- 'function' package.
   752 
   753 * HOL/records: generalised field-update to take a function on the
   754 field rather than the new value: r(|A := x|) is translated to A_update
   755 (K x) r The K-combinator that is internally used is called K_record.
   756 INCOMPATIBILITY: Usage of the plain update functions has to be
   757 adapted.
   758  
   759 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   760 0 * x = 0, which are required for a semiring.  Richer structures do
   761 not inherit from semiring_0 anymore, because this property is a
   762 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   763 semiring_0, there is more to prove, but this is mostly trivial.
   764 
   765 * axclass "recpower" was generalized to arbitrary monoids, not just
   766 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   767 commutativity or a semiring property, add the corresponding classes.
   768 
   769 * Unified locale partial_order with class definition (cf. theory
   770 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   771 
   772 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   773 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   774 Isar level, use abbreviations instead.
   775 
   776 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   777 rarely occuring name references (e.g. ``List.op mem.simps'') require
   778 renaming (e.g. ``List.memberl.simps'').
   779 
   780 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   781 INCOMPATIBILITY.
   782 
   783 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   784 
   785 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   786 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   787 significant changes for setting up numeral syntax for types:
   788 
   789   - new constants Numeral.pred and Numeral.succ instead
   790       of former Numeral.bin_pred and Numeral.bin_succ.
   791   - Use integer operations instead of bin_add, bin_mult and so on.
   792   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   793   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   794 
   795 See HOL/Integ/IntArith.thy for an example setup.
   796 
   797 * New top level command 'normal_form' computes the normal form of a
   798 term that may contain free variables. For example ``normal_form
   799 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   800 suitable for heavy-duty computations because the functions are
   801 compiled to ML first.
   802 
   803 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   804 25 like -->); output depends on the "iff" print_mode, the default is
   805 "A = B" (with priority 50).
   806 
   807 * Renamed constants in HOL.thy and Orderings.thy:
   808     op +   ~> HOL.plus_class.plus
   809     op -   ~> HOL.minus_class.minus
   810     uminus ~> HOL.minus_class.uminus
   811     op *   ~> HOL.times_class.times
   812     op <   ~> Orderings.ord_class.less
   813     op <=  ~> Orderings.ord_class.less_eq
   814 
   815 Adaptions may be required in the following cases:
   816 
   817 a) User-defined constants using any of the names "plus", "minus", "times",
   818 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   819 may go wrong.
   820 INCOMPATIBILITY: use more specific names.
   821 
   822 b) Variables named "plus", "minus", "times", "less", "less_eq"
   823 INCOMPATIBILITY: use more specific names.
   824 
   825 c) Permutative equations (e.g. "a + b = b + a")
   826 Since the change of names also changes the order of terms, permutative
   827 rewrite rules may get applied in a different order. Experience shows that
   828 this is rarely the case (only two adaptions in the whole Isabelle
   829 distribution).
   830 INCOMPATIBILITY: rewrite proofs
   831 
   832 d) ML code directly refering to constant names
   833 This in general only affects hand-written proof tactics, simprocs and so on.
   834 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   835 of const_name ML antiquotations.
   836 
   837 * Relations less (<) and less_eq (<=) are also available on type bool.
   838 Modified syntax to disallow nesting without explicit parentheses,
   839 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   840 
   841 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   842 
   843 * Relation composition operator "op O" now has precedence 75 and binds
   844 stronger than union and intersection. INCOMPATIBILITY.
   845 
   846 * The old set interval syntax "{m..n(}" (and relatives) has been
   847 removed.  Use "{m..<n}" (and relatives) instead.
   848 
   849 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   850 "t = s" to False (by simproc "neq_simproc").  For backward
   851 compatibility this can be disabled by ML "reset use_neq_simproc".
   852 
   853 * "m dvd n" where m and n are numbers is evaluated to True/False by
   854 simp.
   855 
   856 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   857 
   858 * Theorem setsum_mult renamed to setsum_right_distrib.
   859 
   860 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   861 ``rule'' method.
   862 
   863 * Reimplemented methods ``sat'' and ``satx'', with several
   864 improvements: goals no longer need to be stated as "<prems> ==>
   865 False", equivalences (i.e. "=" on type bool) are handled, variable
   866 names of the form "lit_<n>" are no longer reserved, significant
   867 speedup.
   868 
   869 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   870 zChaff is still supported as well.
   871 
   872 * 'inductive' and 'datatype': provide projections of mutual rules,
   873 bundled as foo_bar.inducts;
   874 
   875 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   876 Library.
   877 
   878 * Library: moved theory Accessible_Part to main HOL.
   879 
   880 * Library: added theory Coinductive_List of potentially infinite lists
   881 as greatest fixed-point.
   882 
   883 * Library: added theory AssocList which implements (finite) maps as
   884 association lists.
   885 
   886 * Added proof method ``evaluation'' for efficiently solving a goal
   887 (i.e. a boolean expression) by compiling it to ML. The goal is
   888 "proved" (via an oracle) if it evaluates to True.
   889 
   890 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   891 also when invoked by the simplifier.  This results in the simplifier
   892 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   893 fast_arith_split_limit to 0 to obtain the old behavior.
   894 
   895 * Support for hex (0x20) and binary (0b1001) numerals.
   896 
   897 * New method: reify eqs (t), where eqs are equations for an
   898 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   899 parameter, computes a term s::'b and a list xs::'a list and proves the
   900 theorem I xs s = t. This is also known as reification or quoting. The
   901 resulting theorem is applied to the subgoal to substitute t with I xs
   902 s.  If t is omitted, the subgoal itself is reified.
   903 
   904 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   905 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   906 where f is supposed to be a computable function (in the sense of code
   907 generattion). The method uses reify to compute s and xs as above then
   908 applies corr_thm and uses normalization by evaluation to "prove" f s =
   909 r and finally gets the theorem t = r, which is again applied to the
   910 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   911 
   912 * Reflection: Automatic refification now handels binding, an example
   913 is available in HOL/ex/ReflectionEx.thy
   914 
   915 
   916 *** HOL-Algebra ***
   917 
   918 * Formalisation of ideals and the quotient construction over rings.
   919 
   920 * Order and lattice theory no longer based on records.
   921 INCOMPATIBILITY.
   922 
   923 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   924 greatest_closed.  INCOMPATIBILITY.
   925 
   926 * Method algebra is now set up via an attribute.  For examples see
   927 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   928 of algebraic structures.
   929 
   930 * Renamed theory CRing to Ring.
   931 
   932 
   933 *** HOL-Complex ***
   934 
   935 * Theory Real: new method ferrack implements quantifier elimination
   936 for linear arithmetic over the reals. The quantifier elimination
   937 feature is used only for decision, for compatibility with arith. This
   938 means a goal is either solved or left unchanged, no simplification.
   939 
   940 * Hyperreal: Functions root and sqrt are now defined on negative real
   941 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   942 Nonnegativity side conditions have been removed from many lemmas, so
   943 that more subgoals may now be solved by simplification; potential
   944 INCOMPATIBILITY.
   945 
   946 * Real: New axiomatic classes formalize real normed vector spaces and
   947 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   948 and norm :: 'a => real.
   949 
   950 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   951 from reals into other types. The overloaded constant Reals :: 'a set
   952 is now defined as range of_real; potential INCOMPATIBILITY.
   953 
   954 * Real: ML code generation is supported now and hence also quickcheck.
   955 Reals are implemented as arbitrary precision rationals.
   956 
   957 * Hyperreal: Several constants that previously worked only for the
   958 reals have been generalized, so they now work over arbitrary vector
   959 spaces. Type annotations may need to be added in some cases; potential
   960 INCOMPATIBILITY.
   961 
   962   Infinitesimal  :: ('a::real_normed_vector) star set
   963   HFinite        :: ('a::real_normed_vector) star set
   964   HInfinite      :: ('a::real_normed_vector) star set
   965   approx         :: ('a::real_normed_vector) star => 'a star => bool
   966   monad          :: ('a::real_normed_vector) star => 'a star set
   967   galaxy         :: ('a::real_normed_vector) star => 'a star set
   968   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   969   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   970   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   971   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   972   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   973   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   974   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   975   sgn            :: 'a::real_normed_vector => 'a
   976   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   977 
   978 * Complex: Some complex-specific constants are now abbreviations for
   979 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   980 hnorm.  Other constants have been entirely removed in favor of the
   981 polymorphic versions (INCOMPATIBILITY):
   982 
   983   approx        <-- capprox
   984   HFinite       <-- CFinite
   985   HInfinite     <-- CInfinite
   986   Infinitesimal <-- CInfinitesimal
   987   monad         <-- cmonad
   988   galaxy        <-- cgalaxy
   989   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   990   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   991   (ns)deriv     <-- (ns)cderiv
   992 
   993 
   994 *** ML ***
   995 
   996 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
   997 
   998 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   999 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1000 init only required for impure data.  INCOMPATIBILITY: empty really
  1001 need to be empty (no dependencies on theory content!)
  1002 
  1003 * ML within Isar: antiquotations allow to embed statically-checked
  1004 formal entities in the source, referring to the context available at
  1005 compile-time.  For example:
  1006 
  1007 ML {* @{typ "'a => 'b"} *}
  1008 ML {* @{term "%x. x"} *}
  1009 ML {* @{prop "x == y"} *}
  1010 ML {* @{ctyp "'a => 'b"} *}
  1011 ML {* @{cterm "%x. x"} *}
  1012 ML {* @{cprop "x == y"} *}
  1013 ML {* @{thm asm_rl} *}
  1014 ML {* @{thms asm_rl} *}
  1015 ML {* @{const_name c} *}
  1016 ML {* @{const_syntax c} *}
  1017 ML {* @{context} *}
  1018 ML {* @{theory} *}
  1019 ML {* @{theory Pure} *}
  1020 ML {* @{simpset} *}
  1021 ML {* @{claset} *}
  1022 ML {* @{clasimpset} *}
  1023 
  1024 The same works for sources being ``used'' within an Isar context.
  1025 
  1026 * ML in Isar: improved error reporting; extra verbosity with
  1027 Toplevel.debug enabled.
  1028 
  1029 * Pure/library:
  1030 
  1031   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1032   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1033 
  1034 The semantics of "burrow" is: "take a function with *simulatanously*
  1035 transforms a list of value, and apply it *simulatanously* to a list of
  1036 list of values of the appropriate type". Compare this with "map" which
  1037 would *not* apply its argument function simulatanously but in
  1038 sequence; "fold_burrow" has an additional context.
  1039 
  1040 * Pure/library: functions map2 and fold2 with curried syntax for
  1041 simultanous mapping and folding:
  1042 
  1043     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1044     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1045 
  1046 * Pure/library: indexed lists - some functions in the Isabelle library
  1047 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1048 given more convenient names and signatures reminiscent of similar
  1049 functions for alists, tables, etc:
  1050 
  1051   val nth: 'a list -> int -> 'a 
  1052   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1053   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1054 
  1055 Note that fold_index starts counting at index 0, not 1 like foldln
  1056 used to.
  1057 
  1058 * Pure/library: added general ``divide_and_conquer'' combinator on
  1059 lists.
  1060 
  1061 * Pure/General/table.ML: the join operations now works via exceptions
  1062 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1063 admits slightly more efficient complex applications.
  1064 
  1065 * Pure: datatype Context.generic joins theory/Proof.context and
  1066 provides some facilities for code that works in either kind of
  1067 context, notably GenericDataFun for uniform theory and proof data.
  1068 
  1069 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1070 use Context.generic instead of just theory.
  1071 
  1072 * Pure: simplified internal attribute type, which is now always
  1073 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1074 vs. local (Proof.context) attributes have been discontinued, while
  1075 minimizing code duplication.  Thm.rule_attribute and
  1076 Thm.declaration_attribute build canonical attributes; see also
  1077 structure Context for further operations on Context.generic, notably
  1078 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1079 declarations and definitions.
  1080 
  1081 * Pure/kernel: consts certification ignores sort constraints given in
  1082 signature declarations.  (This information is not relevant to the
  1083 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1084 potential INCOMPATIBILITY.
  1085 
  1086 * Pure: axiomatic type classes are now purely definitional, with
  1087 explicit proofs of class axioms and super class relations performed
  1088 internally.  See Pure/axclass.ML for the main internal interfaces --
  1089 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1090 AxClass.axiomatize_class/classrel/arity supercede
  1091 Sign.add_classes/classrel/arities.
  1092 
  1093 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1094 global/local versions on theory vs. Proof.context have been
  1095 discontinued; Attrib.syntax and Method.syntax have been adapted
  1096 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1097 attributes, methods, etc.
  1098 
  1099 * Pure: several functions of signature "... -> theory -> theory * ..."
  1100 have been reoriented to "... -> theory -> ... * theory" in order to
  1101 allow natural usage in combination with the ||>, ||>>, |-> and
  1102 fold_map combinators.
  1103 
  1104 * Pure: official theorem names (closed derivations) and additional
  1105 comments (tags) are now strictly separate.  Name hints -- which are
  1106 maintained as tags -- may be attached any time without affecting the
  1107 derivation.
  1108 
  1109 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1110 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1111 achieve the old behaviour.
  1112 
  1113 * Pure: the "Goal" constant is now called "prop", supporting a
  1114 slightly more general idea of ``protecting'' meta-level rule
  1115 statements.
  1116 
  1117 * Pure: Logic.(un)varify only works in a global context, which is now
  1118 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1119 Logic.legacy_(un)varify as temporary workaround.
  1120 
  1121 * Pure: structure Name provides scalable operations for generating
  1122 internal variable names, notably Name.variants etc.  This replaces
  1123 some popular functions from term.ML:
  1124 
  1125   Term.variant		->  Name.variant
  1126   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1127   Term.invent_names	->  Name.invent_list
  1128 
  1129 Note that low-level renaming rarely occurs in new code -- operations
  1130 from structure Variable are used instead (see below).
  1131 
  1132 * Pure: structure Variable provides fundamental operations for proper
  1133 treatment of fixed/schematic variables in a context.  For example,
  1134 Variable.import introduces fixes for schematics of given facts and
  1135 Variable.export reverses the effect (up to renaming) -- this replaces
  1136 various freeze_thaw operations.
  1137 
  1138 * Pure: structure Goal provides simple interfaces for
  1139 init/conclude/finish and tactical prove operations (replacing former
  1140 Tactic.prove).  Goal.prove is the canonical way to prove results
  1141 within a given context; Goal.prove_global is a degraded version for
  1142 theory level goals, including a global Drule.standard.  Note that
  1143 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1144 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1145 in a locale context).
  1146 
  1147 * Isar: simplified treatment of user-level errors, using exception
  1148 ERROR of string uniformly.  Function error now merely raises ERROR,
  1149 without any side effect on output channels.  The Isar toplevel takes
  1150 care of proper display of ERROR exceptions.  ML code may use plain
  1151 handle/can/try; cat_error may be used to concatenate errors like this:
  1152 
  1153   ... handle ERROR msg => cat_error msg "..."
  1154 
  1155 Toplevel ML code (run directly or through the Isar toplevel) may be
  1156 embedded into the Isar toplevel with exception display/debug like
  1157 this:
  1158 
  1159   Isar.toplevel (fn () => ...)
  1160 
  1161 INCOMPATIBILITY, removed special transform_error facilities, removed
  1162 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1163 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1164 -- use plain ERROR instead.
  1165 
  1166 * Isar: theory setup now has type (theory -> theory), instead of a
  1167 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1168 
  1169 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1170 subject to ProofContext.debug/verbose flags.
  1171 
  1172 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1173 theory before entering a proof state.  Transactions now always see a
  1174 quasi-functional intermediate checkpoint, both in interactive and
  1175 batch mode.
  1176 
  1177 * Simplifier: the simpset of a running simplification process now
  1178 contains a proof context (cf. Simplifier.the_context), which is the
  1179 very context that the initial simpset has been retrieved from (by
  1180 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1181 (solver, looper etc.) may depend on arbitrary proof data.
  1182 
  1183 * Simplifier.inherit_context inherits the proof context (plus the
  1184 local bounds) of the current simplification process; any simproc
  1185 etc. that calls the Simplifier recursively should do this!  Removed
  1186 former Simplifier.inherit_bounds, which is already included here --
  1187 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1188 specify an explicit context using Simplifier.context/theory_context.
  1189 
  1190 * Simplifier/Classical Reasoner: more abstract interfaces
  1191 change_simpset/claset for modifying the simpset/claset reference of a
  1192 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1193 INCOMPATIBILITY.
  1194 
  1195 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1196 "Trueprop" etc.
  1197 
  1198 
  1199 *** System ***
  1200 
  1201 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1202 locations -- now includes the Isabelle version identifier as well.
  1203 This simplifies use of multiple Isabelle installations.
  1204 
  1205 * isabelle-process: option -S (secure mode) disables some critical
  1206 operations, notably runtime compilation and evaluation of ML source
  1207 code.
  1208 
  1209 
  1210 New in Isabelle2005 (October 2005)
  1211 ----------------------------------
  1212 
  1213 *** General ***
  1214 
  1215 * Theory headers: the new header syntax for Isar theories is
  1216 
  1217   theory <name>
  1218   imports <theory1> ... <theoryN>
  1219   uses <file1> ... <fileM>
  1220   begin
  1221 
  1222 where the 'uses' part is optional.  The previous syntax
  1223 
  1224   theory <name> = <theory1> + ... + <theoryN>:
  1225 
  1226 will disappear in the next release.  Use isatool fixheaders to convert
  1227 existing theory files.  Note that there is no change in ancient
  1228 non-Isar theories now, but these will disappear soon.
  1229 
  1230 * Theory loader: parent theories can now also be referred to via
  1231 relative and absolute paths.
  1232 
  1233 * Command 'find_theorems' searches for a list of criteria instead of a
  1234 list of constants. Known criteria are: intro, elim, dest, name:string,
  1235 simp:term, and any term. Criteria can be preceded by '-' to select
  1236 theorems that do not match. Intro, elim, dest select theorems that
  1237 match the current goal, name:s selects theorems whose fully qualified
  1238 name contain s, and simp:term selects all simplification rules whose
  1239 lhs match term.  Any other term is interpreted as pattern and selects
  1240 all theorems matching the pattern. Available in ProofGeneral under
  1241 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1242 
  1243   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1244 
  1245 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1246 matching the current goal as introduction rule and not having "HOL."
  1247 in their name (i.e. not being defined in theory HOL).
  1248 
  1249 * Command 'thms_containing' has been discontinued in favour of
  1250 'find_theorems'; INCOMPATIBILITY.
  1251 
  1252 * Communication with Proof General is now 8bit clean, which means that
  1253 Unicode text in UTF-8 encoding may be used within theory texts (both
  1254 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1255 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1256 
  1257   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1258   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1259 
  1260 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1261 Classical Reasoner.  Typical big applications run around 2 times
  1262 faster.
  1263 
  1264 
  1265 *** Document preparation ***
  1266 
  1267 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1268 of raw sources.  Only those symbols that do not require additional
  1269 LaTeX packages (depending on comments in isabellesym.sty) are
  1270 displayed properly, everything else is left verbatim.  isatool display
  1271 and isatool print are used as front ends (these are subject to the
  1272 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1273 
  1274 * Command tags control specific markup of certain regions of text,
  1275 notably folding and hiding.  Predefined tags include "theory" (for
  1276 theory begin and end), "proof" for proof commands, and "ML" for
  1277 commands involving ML code; the additional tags "visible" and
  1278 "invisible" are unused by default.  Users may give explicit tag
  1279 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1280 interpretation of tags is determined by the LaTeX job during document
  1281 preparation: see option -V of isatool usedir, or options -n and -t of
  1282 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1283 \isadroptag.
  1284 
  1285 Several document versions may be produced at the same time via isatool
  1286 usedir (the generated index.html will link all of them).  Typical
  1287 specifications include ''-V document=theory,proof,ML'' to present
  1288 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1289 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1290 these parts without any formal replacement text.  The Isabelle site
  1291 default settings produce ''document'' and ''outline'' versions as
  1292 specified above.
  1293 
  1294 * Several new antiquotations:
  1295 
  1296   @{term_type term} prints a term with its type annotated;
  1297 
  1298   @{typeof term} prints the type of a term;
  1299 
  1300   @{const const} is the same as @{term const}, but checks that the
  1301   argument is a known logical constant;
  1302 
  1303   @{term_style style term} and @{thm_style style thm} print a term or
  1304   theorem applying a "style" to it
  1305 
  1306   @{ML text}
  1307 
  1308 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1309 definitions, equations, inequations etc., 'concl' printing only the
  1310 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1311 to print the specified premise.  TermStyle.add_style provides an ML
  1312 interface for introducing further styles.  See also the "LaTeX Sugar"
  1313 document practical applications.  The ML antiquotation prints
  1314 type-checked ML expressions verbatim.
  1315 
  1316 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1317 and 'text' support optional locale specification '(in loc)', which
  1318 specifies the default context for interpreting antiquotations.  For
  1319 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1320 
  1321 * Option 'locale=NAME' of antiquotations specifies an alternative
  1322 context interpreting the subsequent argument.  For example: @{thm
  1323 [locale=lattice] inf_assoc}.
  1324 
  1325 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1326 a proof context.
  1327 
  1328 * Proper output of antiquotations for theory commands involving a
  1329 proof context (such as 'locale' or 'theorem (in loc) ...').
  1330 
  1331 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1332 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1333 
  1334 * isatool usedir: new option -C (default true) controls whether option
  1335 -D should include a copy of the original document directory; -C false
  1336 prevents unwanted effects such as copying of administrative CVS data.
  1337 
  1338 
  1339 *** Pure ***
  1340 
  1341 * Considerably improved version of 'constdefs' command.  Now performs
  1342 automatic type-inference of declared constants; additional support for
  1343 local structure declarations (cf. locales and HOL records), see also
  1344 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1345 sequential dependencies of definitions within a single 'constdefs'
  1346 section; moreover, the declared name needs to be an identifier.  If
  1347 all fails, consider to fall back on 'consts' and 'defs' separately.
  1348 
  1349 * Improved indexed syntax and implicit structures.  First of all,
  1350 indexed syntax provides a notational device for subscripted
  1351 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1352 expressions.  Secondly, in a local context with structure
  1353 declarations, number indexes \<^sub>n or the empty index (default
  1354 number 1) refer to a certain fixed variable implicitly; option
  1355 show_structs controls printing of implicit structures.  Typical
  1356 applications of these concepts involve record types and locales.
  1357 
  1358 * New command 'no_syntax' removes grammar declarations (and
  1359 translations) resulting from the given syntax specification, which is
  1360 interpreted in the same manner as for the 'syntax' command.
  1361 
  1362 * 'Advanced' translation functions (parse_translation etc.) may depend
  1363 on the signature of the theory context being presently used for
  1364 parsing/printing, see also isar-ref manual.
  1365 
  1366 * Improved 'oracle' command provides a type-safe interface to turn an
  1367 ML expression of type theory -> T -> term into a primitive rule of
  1368 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1369 is already included here); see also FOL/ex/IffExample.thy;
  1370 INCOMPATIBILITY.
  1371 
  1372 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1373 before); "cI" is no longer bound, use "c.intro" instead.
  1374 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1375 axclasses vs. locales.
  1376 
  1377 * Improved internal renaming of symbolic identifiers -- attach primes
  1378 instead of base 26 numbers.
  1379 
  1380 * New flag show_question_marks controls printing of leading question
  1381 marks in schematic variable names.
  1382 
  1383 * In schematic variable names, *any* symbol following \<^isub> or
  1384 \<^isup> is now treated as part of the base name.  For example, the
  1385 following works without printing of awkward ".0" indexes:
  1386 
  1387   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1388     by simp
  1389 
  1390 * Inner syntax includes (*(*nested*) comments*).
  1391 
  1392 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1393 annotations as "(00...)".
  1394 
  1395 * Clear separation of logical types and nonterminals, where the latter
  1396 may only occur in 'syntax' specifications or type abbreviations.
  1397 Before that distinction was only partially implemented via type class
  1398 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1399 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1400 exotic syntax specifications may require further adaption
  1401 (e.g. Cube/Cube.thy).
  1402 
  1403 * Removed obsolete type class "logic", use the top sort {} instead.
  1404 Note that non-logical types should be declared as 'nonterminals'
  1405 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1406 specifications.
  1407 
  1408 * Attributes 'induct' and 'cases': type or set names may now be
  1409 locally fixed variables as well.
  1410 
  1411 * Simplifier: can now control the depth to which conditional rewriting
  1412 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1413 Limit.
  1414 
  1415 * Simplifier: simplification procedures may now take the current
  1416 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1417 interface), which is very useful for calling the Simplifier
  1418 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1419 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1420 low-level mk_simproc no longer applies Logic.varify internally, to
  1421 allow for use in a context of fixed variables.
  1422 
  1423 * thin_tac now works even if the assumption being deleted contains !!
  1424 or ==>.  More generally, erule now works even if the major premise of
  1425 the elimination rule contains !! or ==>.
  1426 
  1427 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1428 
  1429 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1430 from Pure, which contains all common declarations already.  Both
  1431 theories are defined via plain Isabelle/Isar .thy files.
  1432 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1433 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1434 use isatool fixcpure to adapt your theory and ML sources.
  1435 
  1436 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1437 selections of theorems in named facts via index ranges.
  1438 
  1439 * 'print_theorems': in theory mode, really print the difference
  1440 wrt. the last state (works for interactive theory development only),
  1441 in proof mode print all local facts (cf. 'print_facts');
  1442 
  1443 * 'hide': option '(open)' hides only base names.
  1444 
  1445 * More efficient treatment of intermediate checkpoints in interactive
  1446 theory development.
  1447 
  1448 * Code generator is now invoked via code_module (incremental code
  1449 generation) and code_library (modular code generation, ML structures
  1450 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1451 must be quoted when used as identifiers.
  1452 
  1453 * New 'value' command for reading, evaluating and printing terms using
  1454 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1455 quoted when used as identifier.
  1456 
  1457 
  1458 *** Locales ***
  1459 
  1460 * New commands for the interpretation of locale expressions in
  1461 theories (1), locales (2) and proof contexts (3).  These generate
  1462 proof obligations from the expression specification.  After the
  1463 obligations have been discharged, theorems of the expression are added
  1464 to the theory, target locale or proof context.  The synopsis of the
  1465 commands is a follows:
  1466 
  1467   (1) interpretation expr inst
  1468   (2) interpretation target < expr
  1469   (3) interpret expr inst
  1470 
  1471 Interpretation in theories and proof contexts require a parameter
  1472 instantiation of terms from the current context.  This is applied to
  1473 specifications and theorems of the interpreted expression.
  1474 Interpretation in locales only permits parameter renaming through the
  1475 locale expression.  Interpretation is smart in that interpretations
  1476 that are active already do not occur in proof obligations, neither are
  1477 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1478 inspect active interpretations of a particular locale.  For details,
  1479 see the Isar Reference manual.  Examples can be found in
  1480 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1481 
  1482 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1483 'interpret' instead.
  1484 
  1485 * New context element 'constrains' for adding type constraints to
  1486 parameters.
  1487 
  1488 * Context expressions: renaming of parameters with syntax
  1489 redeclaration.
  1490 
  1491 * Locale declaration: 'includes' disallowed.
  1492 
  1493 * Proper static binding of attribute syntax -- i.e. types / terms /
  1494 facts mentioned as arguments are always those of the locale definition
  1495 context, independently of the context of later invocations.  Moreover,
  1496 locale operations (renaming and type / term instantiation) are applied
  1497 to attribute arguments as expected.
  1498 
  1499 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1500 actual attributes; rare situations may require Attrib.attribute to
  1501 embed those attributes into Attrib.src that lack concrete syntax.
  1502 Attribute implementations need to cooperate properly with the static
  1503 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1504 Attrib.XXX_thm etc. already do the right thing without further
  1505 intervention.  Only unusual applications -- such as "where" or "of"
  1506 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1507 on the context and the facts involved -- may have to assign parsed
  1508 values to argument tokens explicitly.
  1509 
  1510 * Changed parameter management in theorem generation for long goal
  1511 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1512 theorem statement in rare situations.
  1513 
  1514 * Locale inspection command 'print_locale' omits notes elements.  Use
  1515 'print_locale!' to have them included in the output.
  1516 
  1517 
  1518 *** Provers ***
  1519 
  1520 * Provers/hypsubst.ML: improved version of the subst method, for
  1521 single-step rewriting: it now works in bound variable contexts. New is
  1522 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1523 rewrite a different subterm than the original subst method, which is
  1524 still available as 'simplesubst'.
  1525 
  1526 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1527 and quasi orders.
  1528 
  1529 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1530 reflexive-transitive closure of relations.
  1531 
  1532 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1533 limit (previously hard-coded with a value of 20) user-definable.
  1534 
  1535 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1536 is peformed already.  Object-logics merely need to finish their
  1537 initial simpset configuration as before.  INCOMPATIBILITY.
  1538 
  1539 
  1540 *** HOL ***
  1541 
  1542 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1543 
  1544   syntax (epsilon)
  1545     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1546 
  1547 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1548 and x-symbol; use option '-m epsilon' to get it actually printed.
  1549 Moreover, the mathematically important symbolic identifier \<epsilon>
  1550 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1551 
  1552 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1553 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1554 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1555 support corresponding Isar calculations.
  1556 
  1557 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1558 instead of ":".
  1559 
  1560 * theory SetInterval: changed the syntax for open intervals:
  1561 
  1562   Old       New
  1563   {..n(}    {..<n}
  1564   {)n..}    {n<..}
  1565   {m..n(}   {m..<n}
  1566   {)m..n}   {m<..n}
  1567   {)m..n(}  {m<..<n}
  1568 
  1569 The old syntax is still supported but will disappear in the next
  1570 release.  For conversion use the following Emacs search and replace
  1571 patterns (these are not perfect but work quite well):
  1572 
  1573   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1574   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1575 
  1576 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1577 equalities in commutative rings; method 'algebra' provides a generic
  1578 interface.
  1579 
  1580 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1581 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1582 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1583 be a tuple pattern.
  1584 
  1585 Some new syntax forms are available:
  1586 
  1587   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1588   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1589   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1590   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1591 
  1592 The latter form "\<Sum>x < k. e" used to be based on a separate
  1593 function "Summation", which has been discontinued.
  1594 
  1595 * theory Finite_Set: in structured induction proofs, the insert case
  1596 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1597 (insert F x)'.
  1598 
  1599 * The 'refute' command has been extended to support a much larger
  1600 fragment of HOL, including axiomatic type classes, constdefs and
  1601 typedefs, inductive datatypes and recursion.
  1602 
  1603 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1604 Requires zChaff with proof generation to be installed.  See
  1605 HOL/ex/SAT_Examples.thy for examples.
  1606 
  1607 * Datatype induction via method 'induct' now preserves the name of the
  1608 induction variable. For example, when proving P(xs::'a list) by
  1609 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1610 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1611 in unstructured proof scripts.
  1612 
  1613 * Reworked implementation of records.  Improved scalability for
  1614 records with many fields, avoiding performance problems for type
  1615 inference. Records are no longer composed of nested field types, but
  1616 of nested extension types. Therefore the record type only grows linear
  1617 in the number of extensions and not in the number of fields.  The
  1618 top-level (users) view on records is preserved.  Potential
  1619 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1620 old record representation. The type generated for a record is called
  1621 <record_name>_ext_type.
  1622 
  1623 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1624 proofs triggered by a record definition or a simproc (if
  1625 quick_and_dirty is enabled).  Definitions of large records can take
  1626 quite long.
  1627 
  1628 New simproc record_upd_simproc for simplification of multiple record
  1629 updates enabled by default.  Moreover, trivial updates are also
  1630 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1631 occasionally, since simplification is more powerful by default.
  1632 
  1633 * typedef: proper support for polymorphic sets, which contain extra
  1634 type-variables in the term.
  1635 
  1636 * Simplifier: automatically reasons about transitivity chains
  1637 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1638 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1639 old proofs break occasionally as simplification may now solve more
  1640 goals than previously.
  1641 
  1642 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1643 present.  Works for all partial orders (class "order"), in particular
  1644 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1645 just like y <= x.
  1646 
  1647 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1648 bound variable or a constant then the let is unfolded.  Otherwise
  1649 first a is simplified to b, and then f b is simplified to g. If
  1650 possible we abstract b from g arriving at "let x = b in h x",
  1651 otherwise we unfold the let and arrive at g.  The simproc can be
  1652 enabled/disabled by the reference use_let_simproc.  Potential
  1653 INCOMPATIBILITY since simplification is more powerful by default.
  1654 
  1655 * Classical reasoning: the meson method now accepts theorems as arguments.
  1656 
  1657 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1658 jobs to provide advice on the provability of subgoals.
  1659 
  1660 * Theory OrderedGroup and Ring_and_Field: various additions and
  1661 improvements to faciliate calculations involving equalities and
  1662 inequalities.
  1663 
  1664 The following theorems have been eliminated or modified
  1665 (INCOMPATIBILITY):
  1666 
  1667   abs_eq             now named abs_of_nonneg
  1668   abs_of_ge_0        now named abs_of_nonneg
  1669   abs_minus_eq       now named abs_of_nonpos
  1670   imp_abs_id         now named abs_of_nonneg
  1671   imp_abs_neg_id     now named abs_of_nonpos
  1672   mult_pos           now named mult_pos_pos
  1673   mult_pos_le        now named mult_nonneg_nonneg
  1674   mult_pos_neg_le    now named mult_nonneg_nonpos
  1675   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1676   mult_neg           now named mult_neg_neg
  1677   mult_neg_le        now named mult_nonpos_nonpos
  1678 
  1679 * Theory Parity: added rules for simplifying exponents.
  1680 
  1681 * Theory List:
  1682 
  1683 The following theorems have been eliminated or modified
  1684 (INCOMPATIBILITY):
  1685 
  1686   list_all_Nil       now named list_all.simps(1)
  1687   list_all_Cons      now named list_all.simps(2)
  1688   list_all_conv      now named list_all_iff
  1689   set_mem_eq         now named mem_iff
  1690 
  1691 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1692 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1693 
  1694 
  1695 *** HOL-Complex ***
  1696 
  1697 * Theory RealDef: better support for embedding natural numbers and
  1698 integers in the reals.
  1699 
  1700 The following theorems have been eliminated or modified
  1701 (INCOMPATIBILITY):
  1702 
  1703   exp_ge_add_one_self  now requires no hypotheses
  1704   real_of_int_add      reversed direction of equality (use [symmetric])
  1705   real_of_int_minus    reversed direction of equality (use [symmetric])
  1706   real_of_int_diff     reversed direction of equality (use [symmetric])
  1707   real_of_int_mult     reversed direction of equality (use [symmetric])
  1708 
  1709 * Theory RComplete: expanded support for floor and ceiling functions.
  1710 
  1711 * Theory Ln is new, with properties of the natural logarithm
  1712 
  1713 * Hyperreal: There is a new type constructor "star" for making
  1714 nonstandard types.  The old type names are now type synonyms:
  1715 
  1716   hypreal = real star
  1717   hypnat = nat star
  1718   hcomplex = complex star
  1719 
  1720 * Hyperreal: Many groups of similarly-defined constants have been
  1721 replaced by polymorphic versions (INCOMPATIBILITY):
  1722 
  1723   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1724 
  1725   starset      <-- starsetNat, starsetC
  1726   *s*          <-- *sNat*, *sc*
  1727   starset_n    <-- starsetNat_n, starsetC_n
  1728   *sn*         <-- *sNatn*, *scn*
  1729   InternalSets <-- InternalNatSets, InternalCSets
  1730 
  1731   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1732   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1733   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1734   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1735   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1736 
  1737 * Hyperreal: Many type-specific theorems have been removed in favor of
  1738 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1739 
  1740   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1741   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1742   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1743   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1744   right_minus <-- hypreal_add_minus
  1745   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1746   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1747   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1748   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1749   mult_1_right <-- hcomplex_mult_one_right
  1750   mult_zero_left <-- hcomplex_mult_zero_left
  1751   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1752   right_distrib <-- hypnat_add_mult_distrib2
  1753   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1754   right_inverse <-- hypreal_mult_inverse
  1755   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1756   order_refl <-- {hypreal,hypnat}_le_refl
  1757   order_trans <-- {hypreal,hypnat}_le_trans
  1758   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1759   order_less_le <-- {hypreal,hypnat}_less_le
  1760   linorder_linear <-- {hypreal,hypnat}_le_linear
  1761   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1762   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1763   add_nonneg_nonneg <-- hypreal_le_add_order
  1764 
  1765 * Hyperreal: Separate theorems having to do with type-specific
  1766 versions of constants have been merged into theorems that apply to the
  1767 new polymorphic constants (INCOMPATIBILITY):
  1768 
  1769   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1770   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1771   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1772   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1773   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1774   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1775   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1776   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1777   STAR_diff <-- {STAR,STARC}_diff
  1778   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1779     STARC_hcomplex_of_complex}_image_subset
  1780   starset_n_Un <-- starset{Nat,C}_n_Un
  1781   starset_n_Int <-- starset{Nat,C}_n_Int
  1782   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1783   starset_n_diff <-- starset{Nat,C}_n_diff
  1784   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1785   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1786   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1787   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1788   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1789   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1790   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1791   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1792   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1793   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1794   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1795   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1796   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1797   starfun_diff <-- starfun{C,RC,CR}_diff
  1798   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1799   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1800   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1801   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1802   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1803   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1804   starfun_Id <-- starfunC_Id
  1805   starfun_approx <-- starfun{Nat,CR}_approx
  1806   starfun_capprox <-- starfun{C,RC}_capprox
  1807   starfun_abs <-- starfunNat_rabs
  1808   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1809   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1810   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1811   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1812   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1813   starfun_add_approx <-- starfunCR_add_approx
  1814   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1815   starfun_divide <-- starfun{C,CR,RC}_divide
  1816   starfun_n <-- starfun{Nat,C}_n
  1817   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1818   starfun_n_add <-- starfun{Nat,C}_n_add
  1819   starfun_n_add_minus <-- starfunNat_n_add_minus
  1820   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1821   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1822   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1823 
  1824   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1825   star_n_minus <-- {hypreal,hcomplex}_minus
  1826   star_n_diff <-- {hypreal,hcomplex}_diff
  1827   star_n_mult <-- {hypreal,hcomplex}_mult
  1828   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1829   star_n_le <-- {hypreal,hypnat}_le
  1830   star_n_less <-- {hypreal,hypnat}_less
  1831   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1832   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1833   star_n_abs <-- hypreal_hrabs
  1834   star_n_divide <-- hcomplex_divide
  1835 
  1836   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1837   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1838   star_of_diff <-- hypreal_of_real_diff
  1839   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1840   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1841   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1842   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1843   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1844   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1845   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1846   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1847   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1848   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1849   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1850   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1851   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1852   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1853   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1854   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1855   star_of_power <-- hypreal_of_real_power
  1856   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1857 
  1858 * Hyperreal: new method "transfer" that implements the transfer
  1859 principle of nonstandard analysis. With a subgoal that mentions
  1860 nonstandard types like "'a star", the command "apply transfer"
  1861 replaces it with an equivalent one that mentions only standard types.
  1862 To be successful, all free variables must have standard types; non-
  1863 standard variables must have explicit universal quantifiers.
  1864 
  1865 * Hyperreal: A theory of Taylor series.
  1866 
  1867 
  1868 *** HOLCF ***
  1869 
  1870 * Discontinued special version of 'constdefs' (which used to support
  1871 continuous functions) in favor of the general Pure one with full
  1872 type-inference.
  1873 
  1874 * New simplification procedure for solving continuity conditions; it
  1875 is much faster on terms with many nested lambda abstractions (cubic
  1876 instead of exponential time).
  1877 
  1878 * New syntax for domain package: selector names are now optional.
  1879 Parentheses should be omitted unless argument is lazy, for example:
  1880 
  1881   domain 'a stream = cons "'a" (lazy "'a stream")
  1882 
  1883 * New command 'fixrec' for defining recursive functions with pattern
  1884 matching; defining multiple functions with mutual recursion is also
  1885 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1886 sinr, or any data constructor defined by the domain package. The given
  1887 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1888 syntax and examples.
  1889 
  1890 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1891 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1892 but the proof obligation additionally includes an admissibility
  1893 requirement. The packages generate instances of class cpo or pcpo,
  1894 with continuity and strictness theorems for Rep and Abs.
  1895 
  1896 * HOLCF: Many theorems have been renamed according to a more standard naming
  1897 scheme (INCOMPATIBILITY):
  1898 
  1899   foo_inject:  "foo$x = foo$y ==> x = y"
  1900   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1901   foo_less:    "(foo$x << foo$y) = (x << y)"
  1902   foo_strict:  "foo$UU = UU"
  1903   foo_defined: "... ==> foo$x ~= UU"
  1904   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1905 
  1906 
  1907 *** ZF ***
  1908 
  1909 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1910 including the First Isomorphism Theorem (on quotienting by the kernel
  1911 of a homomorphism).
  1912 
  1913 * ZF/Simplifier: install second copy of type solver that actually
  1914 makes use of TC rules declared to Isar proof contexts (or locales);
  1915 the old version is still required for ML proof scripts.
  1916 
  1917 
  1918 *** Cube ***
  1919 
  1920 * Converted to Isar theory format; use locales instead of axiomatic
  1921 theories.
  1922 
  1923 
  1924 *** ML ***
  1925 
  1926 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1927 for ||>, ||>>, |>>,
  1928 
  1929 * Pure/library.ML no longer defines its own option datatype, but uses
  1930 that of the SML basis, which has constructors NONE and SOME instead of
  1931 None and Some, as well as exception Option.Option instead of OPTION.
  1932 The functions the, if_none, is_some, is_none have been adapted
  1933 accordingly, while Option.map replaces apsome.
  1934 
  1935 * Pure/library.ML: the exception LIST has been given up in favour of
  1936 the standard exceptions Empty and Subscript, as well as
  1937 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1938 superceded by the standard hd and tl functions etc.
  1939 
  1940 A number of basic list functions are no longer exported to the ML
  1941 toplevel, as they are variants of predefined functions.  The following
  1942 suggests how one can translate existing code:
  1943 
  1944     rev_append xs ys = List.revAppend (xs, ys)
  1945     nth_elem (i, xs) = List.nth (xs, i)
  1946     last_elem xs = List.last xs
  1947     flat xss = List.concat xss
  1948     seq fs = List.app fs
  1949     partition P xs = List.partition P xs
  1950     mapfilter f xs = List.mapPartial f xs
  1951 
  1952 * Pure/library.ML: several combinators for linear functional
  1953 transformations, notably reverse application and composition:
  1954 
  1955   x |> f                f #> g
  1956   (x, y) |-> f          f #-> g
  1957 
  1958 * Pure/library.ML: introduced/changed precedence of infix operators:
  1959 
  1960   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1961   infix 2 ?;
  1962   infix 3 o oo ooo oooo;
  1963   infix 4 ~~ upto downto;
  1964 
  1965 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1966 infix operators.
  1967 
  1968 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1969 fold_map support linear functional transformations and nesting.  For
  1970 example:
  1971 
  1972   fold f [x1, ..., xN] y =
  1973     y |> f x1 |> ... |> f xN
  1974 
  1975   (fold o fold) f [xs1, ..., xsN] y =
  1976     y |> fold f xs1 |> ... |> fold f xsN
  1977 
  1978   fold f [x1, ..., xN] =
  1979     f x1 #> ... #> f xN
  1980 
  1981   (fold o fold) f [xs1, ..., xsN] =
  1982     fold f xs1 #> ... #> fold f xsN
  1983 
  1984 * Pure/library.ML: the following selectors on type 'a option are
  1985 available:
  1986 
  1987   the:               'a option -> 'a  (*partial*)
  1988   these:             'a option -> 'a  where 'a = 'b list
  1989   the_default: 'a -> 'a option -> 'a
  1990   the_list:          'a option -> 'a list
  1991 
  1992 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1993 basic operations for association lists, following natural argument
  1994 order; moreover the explicit equality predicate passed here avoids
  1995 potentially expensive polymorphic runtime equality checks.
  1996 The old functions may be expressed as follows:
  1997 
  1998   assoc = uncurry (AList.lookup (op =))
  1999   assocs = these oo AList.lookup (op =)
  2000   overwrite = uncurry (AList.update (op =)) o swap
  2001 
  2002 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2003 
  2004   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2005   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2006 
  2007 replacing make_keylist and keyfilter (occassionally used)
  2008 Naive rewrites:
  2009 
  2010   make_keylist = AList.make
  2011   keyfilter = AList.find (op =)
  2012 
  2013 * eq_fst and eq_snd now take explicit equality parameter, thus
  2014   avoiding eqtypes. Naive rewrites:
  2015 
  2016     eq_fst = eq_fst (op =)
  2017     eq_snd = eq_snd (op =)
  2018 
  2019 * Removed deprecated apl and apr (rarely used).
  2020   Naive rewrites:
  2021 
  2022     apl (n, op) =>>= curry op n
  2023     apr (op, m) =>>= fn n => op (n, m)
  2024 
  2025 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2026 provides a reasonably efficient light-weight implementation of sets as
  2027 lists.
  2028 
  2029 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2030 few new operations; existing lookup and update are now curried to
  2031 follow natural argument order (for use with fold etc.);
  2032 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2033 
  2034 * Pure/General: output via the Isabelle channels of
  2035 writeln/warning/error etc. is now passed through Output.output, with a
  2036 hook for arbitrary transformations depending on the print_mode
  2037 (cf. Output.add_mode -- the first active mode that provides a output
  2038 function wins).  Already formatted output may be embedded into further
  2039 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2040 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2041 accommodate easy composition of diagnostic messages etc.  Programmers
  2042 rarely need to care about Output.output or Output.raw at all, with
  2043 some notable exceptions: Output.output is required when bypassing the
  2044 standard channels (writeln etc.), or in token translations to produce
  2045 properly formatted results; Output.raw is required when capturing
  2046 already output material that will eventually be presented to the user
  2047 a second time.  For the default print mode, both Output.output and
  2048 Output.raw have no effect.
  2049 
  2050 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2051 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2052 cumulative results are displayed at the end of a batch session.
  2053 
  2054 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2055 replaced by File.platform_path and File.shell_path (with appropriate
  2056 hooks).  This provides a clean interface for unusual systems where the
  2057 internal and external process view of file names are different.
  2058 
  2059 * Pure: more efficient orders for basic syntactic entities: added
  2060 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2061 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2062 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2063 orders now -- potential INCOMPATIBILITY for code that depends on a
  2064 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2065 Library.sort_strings on result).
  2066 
  2067 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2068 fold_types traverse types/terms from left to right, observing natural
  2069 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2070 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2071 
  2072 * Pure: name spaces have been refined, with significant changes of the
  2073 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2074 to extern(_table).  The plain name entry path is superceded by a
  2075 general 'naming' context, which also includes the 'policy' to produce
  2076 a fully qualified name and external accesses of a fully qualified
  2077 name; NameSpace.extend is superceded by context dependent
  2078 Sign.declare_name.  Several theory and proof context operations modify
  2079 the naming context.  Especially note Theory.restore_naming and
  2080 ProofContext.restore_naming to get back to a sane state; note that
  2081 Theory.add_path is no longer sufficient to recover from
  2082 Theory.absolute_path in particular.
  2083 
  2084 * Pure: new flags short_names (default false) and unique_names
  2085 (default true) for controlling output of qualified names.  If
  2086 short_names is set, names are printed unqualified.  If unique_names is
  2087 reset, the name prefix is reduced to the minimum required to achieve
  2088 the original result when interning again, even if there is an overlap
  2089 with earlier declarations.
  2090 
  2091 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2092 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2093 (useful for printing error messages).  INCOMPATIBILITY.
  2094 
  2095 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2096 Theory.theory are now identified, referring to the universal
  2097 Context.theory (see Pure/context.ML).  Actual signature and theory
  2098 content is managed as theory data.  The old code and interfaces were
  2099 spread over many files and structures; the new arrangement introduces
  2100 considerable INCOMPATIBILITY to gain more clarity:
  2101 
  2102   Context -- theory management operations (name, identity, inclusion,
  2103     parents, ancestors, merge, etc.), plus generic theory data;
  2104 
  2105   Sign -- logical signature and syntax operations (declaring consts,
  2106     types, etc.), plus certify/read for common entities;
  2107 
  2108   Theory -- logical theory operations (stating axioms, definitions,
  2109     oracles), plus a copy of logical signature operations (consts,
  2110     types, etc.); also a few basic management operations (Theory.copy,
  2111     Theory.merge, etc.)
  2112 
  2113 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2114 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2115 for convenience -- they merely return the theory.
  2116 
  2117 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2118 
  2119 * Pure: the Isar proof context type is already defined early in Pure
  2120 as Context.proof (note that ProofContext.context and Proof.context are
  2121 aliases, where the latter is the preferred name).  This enables other
  2122 Isabelle components to refer to that type even before Isar is present.
  2123 
  2124 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2125 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2126 any of these kinds.  For example, Sign.intern typeK is now
  2127 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2128 Theory.hide_types.  Also note that former
  2129 Theory.hide_classes/types/consts are now
  2130 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2131 internalize their arguments!  INCOMPATIBILITY.
  2132 
  2133 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2134 datatype thmref (with constructors Name and NameSelection) instead of
  2135 plain string -- INCOMPATIBILITY;
  2136 
  2137 * Pure: cases produced by proof methods specify options, where NONE
  2138 means to remove case bindings -- INCOMPATIBILITY in
  2139 (RAW_)METHOD_CASES.
  2140 
  2141 * Pure: the following operations retrieve axioms or theorems from a
  2142 theory node or theory hierarchy, respectively:
  2143 
  2144   Theory.axioms_of: theory -> (string * term) list
  2145   Theory.all_axioms_of: theory -> (string * term) list
  2146   PureThy.thms_of: theory -> (string * thm) list
  2147   PureThy.all_thms_of: theory -> (string * thm) list
  2148 
  2149 * Pure: print_tac now outputs the goal through the trace channel.
  2150 
  2151 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2152 Reference Toplevel.debug (default false) controls detailed printing
  2153 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2154 controls execution profiling -- set to 1 for time and 2 for space
  2155 (both increase the runtime).
  2156 
  2157 * Isar session: The initial use of ROOT.ML is now always timed,
  2158 i.e. the log will show the actual process times, in contrast to the
  2159 elapsed wall-clock time that the outer shell wrapper produces.
  2160 
  2161 * Simplifier: improved handling of bound variables (nameless
  2162 representation, avoid allocating new strings).  Simprocs that invoke
  2163 the Simplifier recursively should use Simplifier.inherit_bounds to
  2164 avoid local name clashes.  Failure to do so produces warnings
  2165 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2166 for further details.
  2167 
  2168 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2169 bindings for all theorems stored within a given theory; this may help
  2170 in porting non-Isar theories to Isar ones, while keeping ML proof
  2171 scripts for the time being.
  2172 
  2173 * ML operator HTML.with_charset specifies the charset begin used for
  2174 generated HTML files.  For example:
  2175 
  2176   HTML.with_charset "utf-8" use_thy "Hebrew";
  2177   HTML.with_charset "utf-8" use_thy "Chinese";
  2178 
  2179 
  2180 *** System ***
  2181 
  2182 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2183 isabelle, isatool etc.).
  2184 
  2185 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2186 isatool doc, isatool mkdir, display_drafts etc.).
  2187 
  2188 * isatool usedir: option -f allows specification of the ML file to be
  2189 used by Isabelle; default is ROOT.ML.
  2190 
  2191 * New isatool version outputs the version identifier of the Isabelle
  2192 distribution being used.
  2193 
  2194 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2195 (containing Boolean satisfiability problems) into Isabelle/HOL
  2196 theories.
  2197 
  2198 
  2199 
  2200 New in Isabelle2004 (April 2004)
  2201 --------------------------------
  2202 
  2203 *** General ***
  2204 
  2205 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2206   Replaces linorder.ML.
  2207 
  2208 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2209   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2210   (\<a>...\<z>), are now considered normal letters, and can therefore
  2211   be used anywhere where an ASCII letter (a...zA...Z) has until
  2212   now. COMPATIBILITY: This obviously changes the parsing of some
  2213   terms, especially where a symbol has been used as a binder, say
  2214   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2215   as an identifier.  Fix it by inserting a space around former
  2216   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2217   existing theory and ML files.
  2218 
  2219 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2220 
  2221 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2222   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2223   a normal (but invisible) letter. For multiple letter subscripts repeat
  2224   \<^isub> like this: x\<^isub>1\<^isub>2.
  2225 
  2226 * Pure: There are now sub-/superscripts that can span more than one
  2227   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2228   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2229   superscript. The new control characters are not identifier parts.
  2230 
  2231 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2232   content of "..." to the latex file instead of \isacntrl... . The "..."
  2233   may consist of any printable characters excluding the end bracket >.
  2234 
  2235 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2236   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2237   declare constants "final", which prevents their being given a definition
  2238   later.  It is useful for constants whose behaviour is fixed axiomatically
  2239   rather than definitionally, such as the meta-logic connectives.
  2240 
  2241 * Pure: 'instance' now handles general arities with general sorts
  2242   (i.e. intersections of classes),
  2243 
  2244 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2245   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2246   It can be changed to alter the colors/layout of generated pages.
  2247 
  2248 
  2249 *** Isar ***
  2250 
  2251 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2252   cut_tac, subgoal_tac and thin_tac:
  2253   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2254     locales are no longer forced to write Isar proof scripts.
  2255     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2256     emulations.
  2257   - INCOMPATIBILITY: names of variables to be instantiated may no
  2258     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2259     This is consistent with the instantiation attribute "where".
  2260 
  2261 * Attributes "where" and "of":
  2262   - Now take type variables of instantiated theorem into account when reading
  2263     the instantiation string.  This fixes a bug that caused instantiated
  2264     theorems to have too special types in some circumstances.
  2265   - "where" permits explicit instantiations of type variables.
  2266 
  2267 * Calculation commands "moreover" and "also" no longer interfere with
  2268   current facts ("this"), admitting arbitrary combinations with "then"
  2269   and derived forms.
  2270 
  2271 * Locales:
  2272   - Goal statements involving the context element "includes" no longer
  2273     generate theorems with internal delta predicates (those ending on
  2274     "_axioms") in the premise.
  2275     Resolve particular premise with <locale>.intro to obtain old form.
  2276   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2277     specification and "includes" elements in goal statement.
  2278   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2279     [intro?] and [elim?] (respectively) by default.
  2280   - Experimental command for instantiation of locales in proof contexts:
  2281         instantiate <label>[<attrs>]: <loc>
  2282     Instantiates locale <loc> and adds all its theorems to the current context
  2283     taking into account their attributes.  Label and attrs are optional
  2284     modifiers, like in theorem declarations.  If present, names of
  2285     instantiated theorems are qualified with <label>, and the attributes
  2286     <attrs> are applied after any attributes these theorems might have already.
  2287       If the locale has assumptions, a chained fact of the form
  2288     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2289     are derived.  The command does not support old-style locales declared
  2290     with "locale (open)".
  2291       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2292 
  2293 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2294   (Isar) contexts.
  2295 
  2296 
  2297 *** HOL ***
  2298 
  2299 * Proof import: new image HOL4 contains the imported library from
  2300   the HOL4 system with about 2500 theorems. It is imported by
  2301   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2302   can be used like any other Isabelle image.  See
  2303   HOL/Import/HOL/README for more information.
  2304 
  2305 * Simplifier:
  2306   - Much improved handling of linear and partial orders.
  2307     Reasoners for linear and partial orders are set up for type classes
  2308     "linorder" and "order" respectively, and are added to the default simpset
  2309     as solvers.  This means that the simplifier can build transitivity chains
  2310     to solve goals from the assumptions.
  2311   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2312     of blast or auto after simplification become unnecessary because the goal
  2313     is solved by simplification already.
  2314 
  2315 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2316     all proved in axiomatic type classes for semirings, rings and fields.
  2317 
  2318 * Numerics:
  2319   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2320     now formalized using the Ring_and_Field theory mentioned above.
  2321   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2322     than before, because now they are set up once in a generic manner.
  2323   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2324     Look for the general versions in Ring_and_Field (and Power if they concern
  2325     exponentiation).
  2326 
  2327 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2328 
  2329 * Records:
  2330   - Record types are now by default printed with their type abbreviation
  2331     instead of the list of all field types. This can be configured via
  2332     the reference "print_record_type_abbr".
  2333   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2334     (not enabled by default).
  2335   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2336     EX x. x = sel r to True (not enabled by default).
  2337   - Tactic "record_split_simp_tac" to split and simplify records added.
  2338 
  2339 * 'specification' command added, allowing for definition by
  2340   specification.  There is also an 'ax_specification' command that
  2341   introduces the new constants axiomatically.
  2342 
  2343 * arith(_tac) is now able to generate counterexamples for reals as well.
  2344 
  2345 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2346 
  2347 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2348   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2349 
  2350 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2351   matrix theory to linear programming.
  2352 
  2353 * Unions and Intersections:
  2354   The latex output syntax of UN and INT has been changed
  2355   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2356   i.e. the index formulae has become a subscript.
  2357   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2358 
  2359 * Unions and Intersections over Intervals:
  2360   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2361   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2362   like in normal math, and corresponding versions for < and for intersection.
  2363 
  2364 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2365   lexicographic dictonary ordering has been added as "lexord".
  2366 
  2367 * ML: the legacy theory structures Int and List have been removed. They had
  2368   conflicted with ML Basis Library structures having the same names.
  2369 
  2370 * 'refute' command added to search for (finite) countermodels.  Only works
  2371   for a fragment of HOL.  The installation of an external SAT solver is
  2372   highly recommended.  See "HOL/Refute.thy" for details.
  2373 
  2374 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2375   formulae under an assignment of free variables to random values.
  2376   In contrast to 'refute', it can deal with inductive datatypes,
  2377   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2378   for examples.
  2379 
  2380 
  2381 *** HOLCF ***
  2382 
  2383 * Streams now come with concatenation and are part of the HOLCF image
  2384 
  2385 
  2386 
  2387 New in Isabelle2003 (May 2003)
  2388 ------------------------------
  2389 
  2390 *** General ***
  2391 
  2392 * Provers/simplifier:
  2393 
  2394   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2395     Assumptions are now subject to complete mutual simplification,
  2396     not just from left to right. The simplifier now preserves
  2397     the order of assumptions.
  2398 
  2399     Potential INCOMPATIBILITY:
  2400 
  2401     -- simp sometimes diverges where the old version did
  2402        not, e.g. invoking simp on the goal
  2403 
  2404         [| P (f x); y = x; f x = f y |] ==> Q
  2405 
  2406        now gives rise to the infinite reduction sequence
  2407 
  2408         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2409 
  2410        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2411        kind of problem.
  2412 
  2413     -- Tactics combining classical reasoner and simplification (such as auto)
  2414        are also affected by this change, because many of them rely on
  2415        simp. They may sometimes diverge as well or yield a different numbers
  2416        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2417        in case of problems. Sometimes subsequent calls to the classical
  2418        reasoner will fail because a preceeding call to the simplifier too
  2419        eagerly simplified the goal, e.g. deleted redundant premises.
  2420 
  2421   - The simplifier trace now shows the names of the applied rewrite rules
  2422 
  2423   - You can limit the number of recursive invocations of the simplifier
  2424     during conditional rewriting (where the simplifie tries to solve the
  2425     conditions before applying the rewrite rule):
  2426     ML "simp_depth_limit := n"
  2427     where n is an integer. Thus you can force termination where previously
  2428     the simplifier would diverge.
  2429 
  2430   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2431 
  2432   - No longer aborts on failed congruence proof.  Instead, the
  2433     congruence is ignored.
  2434 
  2435 * Pure: New generic framework for extracting programs from constructive
  2436   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2437   as HOL/Extraction for some case studies.
  2438 
  2439 * Pure: The main goal of the proof state is no longer shown by default, only
  2440 the subgoals. This behaviour is controlled by a new flag.
  2441    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2442 (ML: Proof.show_main_goal).
  2443 
  2444 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2445 rules whose conclusion matches subgoal 1:
  2446       PG menu: Isabelle/Isar -> Show me -> matching rules
  2447 The rules are ordered by how closely they match the subgoal.
  2448 In particular, rules that solve a subgoal outright are displayed first
  2449 (or rather last, the way they are printed).
  2450 (ML: ProofGeneral.print_intros())
  2451 
  2452 * Pure: New flag trace_unify_fail causes unification to print
  2453 diagnostic information (PG: in trace buffer) when it fails. This is
  2454 useful for figuring out why single step proofs like rule, erule or
  2455 assumption failed.
  2456 
  2457 * Pure: Locale specifications now produce predicate definitions
  2458 according to the body of text (covering assumptions modulo local
  2459 definitions); predicate "loc_axioms" covers newly introduced text,
  2460 while "loc" is cumulative wrt. all included locale expressions; the
  2461 latter view is presented only on export into the global theory
  2462 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2463 on the old view without predicates;
  2464 
  2465 * Pure: predefined locales "var" and "struct" are useful for sharing
  2466 parameters (as in CASL, for example); just specify something like
  2467 ``var x + var y + struct M'' as import;
  2468 
  2469 * Pure: improved thms_containing: proper indexing of facts instead of
  2470 raw theorems; check validity of results wrt. current name space;
  2471 include local facts of proof configuration (also covers active
  2472 locales), cover fixed variables in index; may use "_" in term
  2473 specification; an optional limit for the number of printed facts may
  2474 be given (the default is 40);
  2475 
  2476 * Pure: disallow duplicate fact bindings within new-style theory files
  2477 (batch-mode only);
  2478 
  2479 * Provers: improved induct method: assumptions introduced by case
  2480 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2481 the goal statement); "foo" still refers to all facts collectively;
  2482 
  2483 * Provers: the function blast.overloaded has been removed: all constants
  2484 are regarded as potentially overloaded, which improves robustness in exchange
  2485 for slight decrease in efficiency;
  2486 
  2487 * Provers/linorder: New generic prover for transitivity reasoning over
  2488 linear orders.  Note: this prover is not efficient!
  2489 
  2490 * Isar: preview of problems to finish 'show' now produce an error
  2491 rather than just a warning (in interactive mode);
  2492 
  2493 
  2494 *** HOL ***
  2495 
  2496 * arith(_tac)
  2497 
  2498  - Produces a counter example if it cannot prove a goal.
  2499    Note that the counter example may be spurious if the goal is not a formula
  2500    of quantifier-free linear arithmetic.
  2501    In ProofGeneral the counter example appears in the trace buffer.
  2502 
  2503  - Knows about div k and mod k where k is a numeral of type nat or int.
  2504 
  2505  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2506    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2507    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2508 
  2509 * simp's arithmetic capabilities have been enhanced a bit: it now
  2510 takes ~= in premises into account (by performing a case split);
  2511 
  2512 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2513 are distributed over a sum of terms;
  2514 
  2515 * New tactic "trans_tac" and method "trans" instantiate
  2516 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2517 "<=", "<" and "=").
  2518 
  2519 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2520 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2521 
  2522 * 'typedef' command has new option "open" to suppress the set
  2523 definition;
  2524 
  2525 * functions Min and Max on finite sets have been introduced (theory
  2526 Finite_Set);
  2527 
  2528 * attribute [symmetric] now works for relations as well; it turns
  2529 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2530 
  2531 * induct over a !!-quantified statement (say !!x1..xn):
  2532   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2533 
  2534 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2535 %x. None. Warning: empty_def now refers to the previously hidden definition
  2536 of the empty set.
  2537 
  2538 * Algebra: formalization of classical algebra.  Intended as base for
  2539 any algebraic development in Isabelle.  Currently covers group theory
  2540 (up to Sylow's theorem) and ring theory (Universal Property of
  2541 Univariate Polynomials).  Contributions welcome;
  2542 
  2543 * GroupTheory: deleted, since its material has been moved to Algebra;
  2544 
  2545 * Complex: new directory of the complex numbers with numeric constants,
  2546 nonstandard complex numbers, and some complex analysis, standard and
  2547 nonstandard (Jacques Fleuriot);
  2548 
  2549 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2550 
  2551 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2552 Fleuriot);
  2553 
  2554 * Real/HahnBanach: updated and adapted to locales;
  2555 
  2556 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2557 Gray and Kramer);
  2558 
  2559 * UNITY: added the Meier-Sanders theory of progress sets;
  2560 
  2561 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2562 as abstract algorithms, instantiated to the JVM;
  2563 
  2564 * Bali: Java source language formalization. Type system, operational
  2565 semantics, axiomatic semantics. Supported language features:
  2566 classes, interfaces, objects,virtual methods, static methods,
  2567 static/instance fields, arrays, access modifiers, definite
  2568 assignment, exceptions.
  2569 
  2570 
  2571 *** ZF ***
  2572 
  2573 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2574 universe, etc.);
  2575 
  2576 * Main ZF: virtually all theories converted to new-style format;
  2577 
  2578 
  2579 *** ML ***
  2580 
  2581 * Pure: Tactic.prove provides sane interface for internal proofs;
  2582 omits the infamous "standard" operation, so this is more appropriate
  2583 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2584 
  2585 * Pure: improved error reporting of simprocs;
  2586 
  2587 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2588 up simprocs;
  2589 
  2590 
  2591 *** Document preparation ***
  2592 
  2593 * uses \par instead of \\ for line breaks in theory text. This may
  2594 shift some page breaks in large documents. To get the old behaviour
  2595 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2596 
  2597 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2598 other packages
  2599 
  2600 * \<euro> now needs package babel/greek instead of marvosym (which
  2601 broke \Rightarrow)
  2602 
  2603 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2604 textcomp package)
  2605 
  2606 
  2607 
  2608 New in Isabelle2002 (March 2002)
  2609 --------------------------------
  2610 
  2611 *** Document preparation ***
  2612 
  2613 * greatly simplified document preparation setup, including more
  2614 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2615 instructive isatool mkdir; users should basically be able to get
  2616 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2617 users may run a separate document processing stage manually like this:
  2618 "isatool usedir -D output HOL Test && isatool document Test/output";
  2619 
  2620 * theory dependency graph may now be incorporated into documents;
  2621 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2622 with \includegraphics of LaTeX;
  2623 
  2624 * proper spacing of consecutive markup elements, especially text
  2625 blocks after section headings;
  2626 
  2627 * support bold style (for single symbols only), input syntax is like
  2628 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2629 
  2630 * \<bullet> is now output as bold \cdot by default, which looks much
  2631 better in printed text;
  2632 
  2633 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2634 note that these symbols are currently unavailable in Proof General /
  2635 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2636 
  2637 * isatool latex no longer depends on changed TEXINPUTS, instead
  2638 isatool document copies the Isabelle style files to the target
  2639 location;
  2640 
  2641 
  2642 *** Isar ***
  2643 
  2644 * Pure/Provers: improved proof by cases and induction;
  2645   - 'case' command admits impromptu naming of parameters (such as
  2646     "case (Suc n)");
  2647   - 'induct' method divinates rule instantiation from the inductive
  2648     claim; no longer requires excessive ?P bindings for proper
  2649     instantiation of cases;
  2650   - 'induct' method properly enumerates all possibilities of set/type
  2651     rules; as a consequence facts may be also passed through *type*
  2652     rules without further ado;
  2653   - 'induct' method now derives symbolic cases from the *rulified*
  2654     rule (before it used to rulify cases stemming from the internal
  2655     atomized version); this means that the context of a non-atomic
  2656     statement becomes is included in the hypothesis, avoiding the
  2657     slightly cumbersome show "PROP ?case" form;
  2658   - 'induct' may now use elim-style induction rules without chaining
  2659     facts, using ``missing'' premises from the goal state; this allows
  2660     rules stemming from inductive sets to be applied in unstructured
  2661     scripts, while still benefitting from proper handling of non-atomic
  2662     statements; NB: major inductive premises need to be put first, all
  2663     the rest of the goal is passed through the induction;
  2664   - 'induct' proper support for mutual induction involving non-atomic
  2665     rule statements (uses the new concept of simultaneous goals, see
  2666     below);
  2667   - append all possible rule selections, but only use the first
  2668     success (no backtracking);
  2669   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2670   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2671   - added 'print_induct_rules' (covered by help item in recent Proof
  2672     General versions);
  2673   - moved induct/cases attributes to Pure, methods to Provers;
  2674   - generic method setup instantiated for FOL and HOL;
  2675 
  2676 * Pure: support multiple simultaneous goal statements, for example
  2677 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2678 meta-level mechanism, this acts as if several individual goals had
  2679 been stated separately; in particular common proof methods need to be
  2680 repeated in order to cover all claims; note that a single elimination
  2681 step is *not* sufficient to establish the two conjunctions, so this
  2682 fails:
  2683 
  2684   assume "A & B" then have A and B ..   (*".." fails*)
  2685 
  2686 better use "obtain" in situations as above; alternative refer to
  2687 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2688 
  2689 * Pure: proper integration with ``locales''; unlike the original
  2690 version by Florian Kammller, Isar locales package high-level proof
  2691 contexts rather than raw logical ones (e.g. we admit to include
  2692 attributes everywhere); operations on locales include merge and
  2693 rename; support for implicit arguments (``structures''); simultaneous
  2694 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2695 some examples;
  2696 
  2697 * Pure: the following commands have been ``localized'', supporting a
  2698 target locale specification "(in name)": 'lemma', 'theorem',
  2699 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2700 stored both within the locale and at the theory level (exported and
  2701 qualified by the locale name);
  2702 
  2703 * Pure: theory goals may now be specified in ``long'' form, with
  2704 ad-hoc contexts consisting of arbitrary locale elements. for example
  2705 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2706 definitions may be given, too); the result is a meta-level rule with
  2707 the context elements being discharged in the obvious way;
  2708 
  2709 * Pure: new proof command 'using' allows to augment currently used
  2710 facts after a goal statement ('using' is syntactically analogous to
  2711 'apply', but acts on the goal's facts only); this allows chained facts
  2712 to be separated into parts given before and after a claim, as in
  2713 ``from a and b have C using d and e <proof>'';
  2714 
  2715 * Pure: renamed "antecedent" case to "rule_context";
  2716 
  2717 * Pure: new 'judgment' command records explicit information about the
  2718 object-logic embedding (used by several tools internally); no longer
  2719 use hard-wired "Trueprop";
  2720 
  2721 * Pure: added 'corollary' command;
  2722 
  2723 * Pure: fixed 'token_translation' command;
  2724 
  2725 * Pure: removed obsolete 'exported' attribute;
  2726 
  2727 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2728 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2729 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2730 
  2731 * Pure: method 'atomize' presents local goal premises as object-level
  2732 statements (atomic meta-level propositions); setup controlled via
  2733 rewrite rules declarations of 'atomize' attribute; example
  2734 application: 'induct' method with proper rule statements in improper
  2735 proof *scripts*;
  2736 
  2737 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2738 now consider the syntactic context of assumptions, giving a better
  2739 chance to get type-inference of the arguments right (this is
  2740 especially important for locales);
  2741 
  2742 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2743 mode;
  2744 
  2745 * Pure/obtain: the formal conclusion "thesis", being marked as
  2746 ``internal'', may no longer be reference directly in the text;
  2747 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2748 situations;
  2749 
  2750 * Pure: generic 'sym' attribute which declares a rule both as pure
  2751 'elim?' and for the 'symmetric' operation;
  2752 
  2753 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2754 text; the fixed correlation with particular command syntax has been
  2755 discontinued;
  2756 
  2757 * Pure: new method 'rules' is particularly well-suited for proof
  2758 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2759 but often produces more compact proof terms with less detours;
  2760 
  2761 * Pure/Provers/classical: simplified integration with pure rule
  2762 attributes and methods; the classical "intro?/elim?/dest?"
  2763 declarations coincide with the pure ones; the "rule" method no longer
  2764 includes classically swapped intros; "intro" and "elim" methods no
  2765 longer pick rules from the context; also got rid of ML declarations
  2766 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2767 INCOMPATIBILITY;
  2768 
  2769 * Provers/classical: attribute 'swapped' produces classical inversions
  2770 of introduction rules;
  2771 
  2772 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2773 rules instead of full simplifier context; 'iff' attribute handles
  2774 conditional rules;
  2775 
  2776 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2777 
  2778 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2779 "(permissive)" option to recover old behavior;
  2780 
  2781 * HOL: 'inductive' no longer features separate (collective) attributes
  2782 for 'intros' (was found too confusing);
  2783 
  2784 * HOL: properly declared induction rules less_induct and
  2785 wf_induct_rule;
  2786 
  2787 
  2788 *** HOL ***
  2789 
  2790 * HOL: moved over to sane numeral syntax; the new policy is as
  2791 follows:
  2792 
  2793   - 0 and 1 are polymorphic constants, which are defined on any
  2794   numeric type (nat, int, real etc.);
  2795 
  2796   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2797   binary representation internally;
  2798 
  2799   - type nat has special constructor Suc, and generally prefers Suc 0
  2800   over 1::nat and Suc (Suc 0) over 2::nat;
  2801 
  2802 This change may cause significant problems of INCOMPATIBILITY; here
  2803 are some hints on converting existing sources:
  2804 
  2805   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2806   entities, so expressions involving "-" (unary or binary minus) need
  2807   to be spaced properly;
  2808 
  2809   - existing occurrences of "1" may need to be constraint "1::nat" or
  2810   even replaced by Suc 0; similar for old "2";
  2811 
  2812   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2813 
  2814   - remove all special provisions on numerals in proofs;
  2815 
  2816 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2817 representation (depends on bin_arith_simps in the default context);
  2818 
  2819 * HOL: symbolic syntax for x^2 (numeral 2);
  2820 
  2821 * HOL: the class of all HOL types is now called "type" rather than
  2822 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2823 in axclass/classes, instance/arities, and (usually rare) occurrences
  2824 in typings (of consts etc.); internally the class is called
  2825 "HOL.type", ML programs should refer to HOLogic.typeS;
  2826 
  2827 * HOL/record package improvements:
  2828   - new derived operations "fields" to build a partial record section,
  2829     "extend" to promote a fixed record to a record scheme, and
  2830     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2831     declared as simp by default;
  2832   - shared operations ("more", "fields", etc.) now need to be always
  2833     qualified) --- potential INCOMPATIBILITY;
  2834   - removed "make_scheme" operations (use "make" with "extend") --
  2835     INCOMPATIBILITY;
  2836   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2837   - provides cases/induct rules for use with corresponding Isar
  2838     methods (for concrete records, record schemes, concrete more
  2839     parts, and schematic more parts -- in that order);
  2840   - internal definitions directly based on a light-weight abstract
  2841     theory of product types over typedef rather than datatype;
  2842 
  2843 * HOL: generic code generator for generating executable ML code from
  2844 specifications; specific support for HOL constructs such as inductive
  2845 datatypes and sets, as well as recursive functions; can be invoked
  2846 via 'generate_code' theory section;
  2847 
  2848 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2849 
  2850 * HOL: consolidated and renamed several theories.  In particular:
  2851         Ord.thy has been absorbed into HOL.thy
  2852         String.thy has been absorbed into List.thy
  2853 
  2854 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2855 (beware of argument permutation!);
  2856 
  2857 * HOL: linorder_less_split superseded by linorder_cases;
  2858 
  2859 * HOL/List: "nodups" renamed to "distinct";
  2860 
  2861 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2862 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2863   - Ex_def has changed, now need to use some_eq_ex
  2864 
  2865 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2866 in this (rare) case use:
  2867 
  2868   delSWrapper "split_all_tac"
  2869   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2870 
  2871 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2872 MAY FAIL;
  2873 
  2874 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2875 Isabelle's type classes, ^ on functions and relations has too general
  2876 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2877 necessary to attach explicit type constraints;
  2878 
  2879 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2880 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2881 renamed accordingly (eg "compI" -> "rel_compI").
  2882 
  2883 * HOL: syntax translations now work properly with numerals and records
  2884 expressions;
  2885 
  2886 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2887 of "lam" -- INCOMPATIBILITY;
  2888 
  2889 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2890 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2891 renamed "Product_Type.unit";
  2892 
  2893 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2894 
  2895 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2896 the "cases" method);
  2897 
  2898 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2899 Florian Kammller);
  2900 
  2901 * HOL/IMP: updated and converted to new-style theory format; several
  2902 parts turned into readable document, with proper Isar proof texts and
  2903 some explanations (by Gerwin Klein);
  2904 
  2905 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2906 
  2907 * HOL-Hyperreal is now a logic image;
  2908 
  2909 
  2910 *** HOLCF ***
  2911 
  2912 * Isar: consts/constdefs supports mixfix syntax for continuous
  2913 operations;
  2914 
  2915 * Isar: domain package adapted to new-style theory format, e.g. see
  2916 HOLCF/ex/Dnat.thy;
  2917 
  2918 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2919 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2920 lift.induct_tac, always use UU instead of Undef;
  2921 
  2922 * HOLCF/IMP: updated and converted to new-style theory;
  2923 
  2924 
  2925 *** ZF ***
  2926 
  2927 * Isar: proper integration of logic-specific tools and packages,
  2928 including theory commands '(co)inductive', '(co)datatype',
  2929 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2930 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2931 
  2932 * theory Main no longer includes AC; for the Axiom of Choice, base
  2933 your theory on Main_ZFC;
  2934 
  2935 * the integer library now covers quotients and remainders, with many
  2936 laws relating division to addition, multiplication, etc.;
  2937 
  2938 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2939 typeless version of the formalism;
  2940 
  2941 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2942 format;
  2943 
  2944 * ZF/Induct: new directory for examples of inductive definitions,
  2945 including theory Multiset for multiset orderings; converted to
  2946 new-style theory format;
  2947 
  2948 * ZF: many new theorems about lists, ordinals, etc.;
  2949 
  2950 
  2951 *** General ***
  2952 
  2953 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2954 variable proof controls level of detail: 0 = no proofs (only oracle
  2955 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2956 also ref manual for further ML interfaces;
  2957 
  2958 * Pure/axclass: removed obsolete ML interface
  2959 goal_subclass/goal_arity;
  2960 
  2961 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2962 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2963 separate tokens, so expressions involving minus need to be spaced
  2964 properly;
  2965 
  2966 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2967 rather than "infixl" or "infixr";
  2968 
  2969 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2970 sort constraint specifications in type inference; e.g. "x::_::foo"
  2971 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2972 type variable);
  2973 
  2974 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2975 control output of nested => (types); the default behavior is
  2976 "type_brackets";
  2977 
  2978 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2979 tokens into AST constants;
  2980 
  2981 * Pure/syntax: prefer later declarations of translations and print
  2982 translation functions; potential INCOMPATIBILITY: need to reverse
  2983 multiple declarations for same syntax element constant;
  2984 
  2985 * Pure/show_hyps reset by default (in accordance to existing Isar
  2986 practice);
  2987 
  2988 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2989 addSafter;
  2990 
  2991 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2992 as well;
  2993 
  2994 * system: tested support for MacOS X; should be able to get Isabelle +
  2995 Proof General to work in a plain Terminal after installing Poly/ML
  2996 (e.g. from the Isabelle distribution area) and GNU bash alone
  2997 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2998 support requires further installations, e.g. from
  2999 http://fink.sourceforge.net/);
  3000 
  3001 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3002 
  3003 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3004 of 40 MB), cf. ML_OPTIONS;
  3005 
  3006 * system: Proof General keywords specification is now part of the
  3007 Isabelle distribution (see etc/isar-keywords.el);
  3008 
  3009 * system: support for persistent Proof General sessions (refrain from
  3010 outdating all loaded theories on startup); user may create writable
  3011 logic images like this: ``isabelle -q HOL Test'';
  3012 
  3013 * system: smart selection of Isabelle process versus Isabelle
  3014 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3015 run both "isabelle" and "Isabelle" even if file names are badly
  3016 damaged (executable inspects the case of the first letter of its own
  3017 name); added separate "isabelle-process" and "isabelle-interface";
  3018 
  3019 * system: refrain from any attempt at filtering input streams; no
  3020 longer support ``8bit'' encoding of old isabelle font, instead proper
  3021 iso-latin characters may now be used; the related isatools
  3022 "symbolinput" and "nonascii" have disappeared as well;
  3023 
  3024 * system: removed old "xterm" interface (the print modes "xterm" and
  3025 "xterm_color" are still available for direct use in a suitable
  3026 terminal);
  3027 
  3028 
  3029 
  3030 New in Isabelle99-2 (February 2001)
  3031 -----------------------------------
  3032 
  3033 *** Overview of INCOMPATIBILITIES ***
  3034 
  3035 * HOL: please note that theories in the Library and elsewhere often use the
  3036 new-style (Isar) format; to refer to their theorems in an ML script you must
  3037 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3038 
  3039 * HOL: inductive package no longer splits induction rule aggressively,
  3040 but only as far as specified by the introductions given; the old
  3041 format may be recovered via ML function complete_split_rule or attribute
  3042 'split_rule (complete)';
  3043 
  3044 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3045 gfp_Tarski to gfp_unfold;
  3046 
  3047 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3048 
  3049 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3050 relation); infix "^^" has been renamed "``"; infix "``" has been
  3051 renamed "`"; "univalent" has been renamed "single_valued";
  3052 
  3053 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3054 operation;
  3055 
  3056 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3057 
  3058 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3059 
  3060 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3061 consequence, it is no longer monotonic wrt. the local goal context
  3062 (which is now passed through the inductive cases);
  3063 
  3064 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3065 \<gg> to \<ggreater>;
  3066 
  3067 
  3068 *** Document preparation ***
  3069 
  3070 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3071 available: are "it" for near math-mode best-style output, "sl" for
  3072 slanted text style, and "tt" for plain type-writer; if no
  3073 \isabellestyle command is given, output is according to slanted
  3074 type-writer);
  3075 
  3076 * support sub/super scripts (for single symbols only), input syntax is
  3077 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3078 
  3079 * some more standard symbols; see Appendix A of the system manual for
  3080 the complete list of symbols defined in isabellesym.sty;
  3081 
  3082 * improved isabelle style files; more abstract symbol implementation
  3083 (should now use \isamath{...} and \isatext{...} in custom symbol
  3084 definitions);
  3085 
  3086 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3087 state; Note that presentation of goal states does not conform to
  3088 actual human-readable proof documents.  Please do not include goal
  3089 states into document output unless you really know what you are doing!
  3090 
  3091 * proper indentation of antiquoted output with proportional LaTeX
  3092 fonts;
  3093 
  3094 * no_document ML operator temporarily disables LaTeX document
  3095 generation;
  3096 
  3097 * isatool unsymbolize tunes sources for plain ASCII communication;
  3098 
  3099 
  3100 *** Isar ***
  3101 
  3102 * Pure: Isar now suffers initial goal statements to contain unbound
  3103 schematic variables (this does not conform to actual readable proof
  3104 documents, due to unpredictable outcome and non-compositional proof
  3105 checking); users who know what they are doing may use schematic goals
  3106 for Prolog-style synthesis of proven results;
  3107 
  3108 * Pure: assumption method (an implicit finishing) now handles actual
  3109 rules as well;
  3110 
  3111 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3112 initial goal, declare "that" only as Pure intro (only for single
  3113 steps); the "that" rule assumption may now be involved in implicit
  3114 finishing, thus ".." becomes a feasible for trivial obtains;
  3115 
  3116 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3117 instance proofs may be performed by "..";
  3118 
  3119 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3120 statements as well;
  3121 
  3122 * Pure: more robust selection of calculational rules;
  3123 
  3124 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3125 rule (as well as the assumption rule);
  3126 
  3127 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3128 lemmas, using the graph browser tool;
  3129 
  3130 * Pure: predict failure of "show" in interactive mode;
  3131 
  3132 * Pure: 'thms_containing' now takes actual terms as arguments;
  3133 
  3134 * HOL: improved method 'induct' --- now handles non-atomic goals
  3135 (potential INCOMPATIBILITY); tuned error handling;
  3136 
  3137 * HOL: cases and induct rules now provide explicit hints about the
  3138 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3139 any remaining facts are inserted into the goal verbatim;
  3140 
  3141 * HOL: local contexts (aka cases) may now contain term bindings as
  3142 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3143 the result to be shown in each case;
  3144 
  3145 * HOL: added 'recdef_tc' command;
  3146 
  3147 * isatool convert assists in eliminating legacy ML scripts;
  3148 
  3149 
  3150 *** HOL ***
  3151 
  3152 * HOL/Library: a collection of generic theories to be used together
  3153 with main HOL; the theory loader path already includes this directory
  3154 by default; the following existing theories have been moved here:
  3155 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3156 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3157 
  3158 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3159 modelling and verification task performed in Isabelle/HOL +
  3160 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3161 
  3162 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3163 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3164 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3165 'domain', this makes the theory consistent with mathematical
  3166 literature;
  3167 
  3168 * HOL basics: added overloaded operations "inverse" and "divide"
  3169 (infix "/"), syntax for generic "abs" operation, generic summation
  3170 operator \<Sum>;
  3171 
  3172 * HOL/typedef: simplified package, provide more useful rules (see also
  3173 HOL/subset.thy);
  3174 
  3175 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3176 now expressed as a proper nested rule (old-style tactic scripts may
  3177 require atomize_strip_tac to cope with non-atomic premises);
  3178 
  3179 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3180 to "split_conv" (old name still available for compatibility);
  3181 
  3182 * HOL: improved concrete syntax for strings (e.g. allows translation
  3183 rules with string literals);
  3184 
  3185 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3186  and Fleuriot's mechanization of analysis, including the transcendental
  3187  functions for the reals;
  3188 
  3189 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3190 
  3191 
  3192 *** CTT ***
  3193 
  3194 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3195 "lam" is displayed as TWO lambda-symbols
  3196 
  3197 * CTT: theory Main now available, containing everything (that is, Bool
  3198 and Arith);
  3199 
  3200 
  3201 *** General ***
  3202 
  3203 * Pure: the Simplifier has been implemented properly as a derived rule
  3204 outside of the actual kernel (at last!); the overall performance
  3205 penalty in practical applications is about 50%, while reliability of
  3206 the Isabelle inference kernel has been greatly improved;
  3207 
  3208 * print modes "brackets" and "no_brackets" control output of nested =>
  3209 (types) and ==> (props); the default behaviour is "brackets";
  3210 
  3211 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3212 as assumptions as well;
  3213 
  3214 * system: support Poly/ML 4.0;
  3215 
  3216 * system: isatool install handles KDE version 1 or 2;
  3217 
  3218 
  3219 
  3220 New in Isabelle99-1 (October 2000)
  3221 ----------------------------------
  3222 
  3223 *** Overview of INCOMPATIBILITIES ***
  3224 
  3225 * HOL: simplification of natural numbers is much changed; to partly
  3226 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3227 issue the following ML commands:
  3228 
  3229   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3230   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3231 
  3232 * HOL: simplification no longer dives into case-expressions; this is
  3233 controlled by "t.weak_case_cong" for each datatype t;
  3234 
  3235 * HOL: nat_less_induct renamed to less_induct;
  3236 
  3237 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3238 fixsome to patch .thy and .ML sources automatically;
  3239 
  3240   select_equality  -> some_equality
  3241   select_eq_Ex     -> some_eq_ex
  3242   selectI2EX       -> someI2_ex
  3243   selectI2         -> someI2
  3244   selectI          -> someI
  3245   select1_equality -> some1_equality
  3246   Eps_sym_eq       -> some_sym_eq_trivial
  3247   Eps_eq           -> some_eq_trivial
  3248 
  3249 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3250 
  3251 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3252 instead);
  3253 
  3254 * HOL: the recursion equations generated by 'recdef' are now called
  3255 f.simps instead of f.rules;
  3256 
  3257 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3258 
  3259 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3260 sometimes be needed;
  3261 
  3262 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3263 
  3264 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3265 
  3266 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3267 product is now "<*>" instead of "Times"; the lexicographic product is
  3268 now "<*lex*>" instead of "**";
  3269 
  3270 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3271 of main HOL, but was unused); better use HOL's datatype package;
  3272 
  3273 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3274 the old syntax may be recovered as follows:
  3275 
  3276   syntax (symbols)
  3277     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3278       (infixl "\\<oplus>" 100)
  3279 
  3280 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3281 
  3282 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3283 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3284 internally;
  3285 
  3286 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3287 changed from A/r to A//r;
  3288 
  3289 * ZF: new treatment of arithmetic (nat & int) may break some old
  3290 proofs;
  3291 
  3292 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3293 rulify -> rule_format, elimify -> elim_format, ...);
  3294 
  3295 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3296 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3297 should have to change intro!! to intro? only); replaced "delrule" by
  3298 "rule del";
  3299 
  3300 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3301 
  3302 * Provers: strengthened force_tac by using new first_best_tac;
  3303 
  3304 * LaTeX document preparation: several changes of isabelle.sty (see
  3305 lib/texinputs);
  3306 
  3307 
  3308 *** Document preparation ***
  3309 
  3310 * formal comments (text blocks etc.) in new-style theories may now
  3311 contain antiquotations of thm/prop/term/typ/text to be presented
  3312 according to latex print mode; concrete syntax is like this:
  3313 @{term[show_types] "f(x) = a + x"};
  3314 
  3315 * isatool mkdir provides easy setup of Isabelle session directories,
  3316 including proper document sources;
  3317 
  3318 * generated LaTeX sources are now deleted after successful run
  3319 (isatool document -c); may retain a copy somewhere else via -D option
  3320 of isatool usedir;
  3321 
  3322 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3323 style files, achieving self-contained LaTeX sources and simplifying
  3324 LaTeX debugging;
  3325 
  3326 * old-style theories now produce (crude) LaTeX output as well;
  3327 
  3328 * browser info session directories are now self-contained (may be put
  3329 on WWW server seperately); improved graphs of nested sessions; removed
  3330 graph for 'all sessions';
  3331 
  3332 * several improvements in isabelle style files; \isabellestyle{it}
  3333 produces fake math mode output; \isamarkupheader is now \section by
  3334 default; see lib/texinputs/isabelle.sty etc.;
  3335 
  3336 
  3337 *** Isar ***
  3338 
  3339 * Isar/Pure: local results and corresponding term bindings are now
  3340 subject to Hindley-Milner polymorphism (similar to ML); this
  3341 accommodates incremental type-inference very nicely;
  3342 
  3343 * Isar/Pure: new derived language element 'obtain' supports
  3344 generalized existence reasoning;
  3345 
  3346 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3347 support accumulation of results, without applying any rules yet;
  3348 useful to collect intermediate results without explicit name
  3349 references, and for use with transitivity rules with more than 2
  3350 premises;
  3351 
  3352 * Isar/Pure: scalable support for case-analysis type proofs: new
  3353 'case' language element refers to local contexts symbolically, as
  3354 produced by certain proof methods; internally, case names are attached
  3355 to theorems as "tags";
  3356 
  3357 * Isar/Pure: theory command 'hide' removes declarations from
  3358 class/type/const name spaces;
  3359 
  3360 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3361 indicate potential overloading;
  3362 
  3363 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3364 
  3365 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3366 "{a,b,c}" instead of {a,b,c};
  3367 
  3368 * Isar/Pure now provides its own version of intro/elim/dest
  3369 attributes; useful for building new logics, but beware of confusion
  3370 with the version in Provers/classical;
  3371 
  3372 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3373 case name 'antecedent';
  3374 
  3375 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3376 to the current context is now done automatically);
  3377 
  3378 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3379 for definining proof methods in ML;
  3380 
  3381 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3382 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3383 most cases, one should have to change intro!! to intro? only);
  3384 replaced "delrule" by "rule del";
  3385 
  3386 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3387 'symmetric' attribute (the latter supercedes [RS sym]);
  3388 
  3389 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3390 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3391 well (including splits);
  3392 
  3393 * Isar/Provers: Simplifier and Classical methods now support all kind
  3394 of modifiers used in the past, including 'cong', 'iff', etc.
  3395 
  3396 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3397 of Simplifier and Classical reasoner);
  3398 
  3399 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3400 now support named cases; major packages (inductive, datatype, primrec,
  3401 recdef) support case names and properly name parameters;
  3402 
  3403 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3404 monotonicity conditions are extracted to be proven at end of
  3405 calculations;
  3406 
  3407 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3408 method anyway;
  3409 
  3410 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3411 split_if split_if_asm; datatype package provides theorems foo.splits =
  3412 foo.split foo.split_asm for each datatype;
  3413 
  3414 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3415 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3416 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3417 use "(cases (simplified))" method in proper proof texts);
  3418 
  3419 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3420 
  3421 * Isar: names of theorems etc. may be natural numbers as well;
  3422 
  3423 * Isar: 'pr' command: optional arguments for goals_limit and
  3424 ProofContext.prems_limit; no longer prints theory contexts, but only
  3425 proof states;
  3426 
  3427 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3428 additional print modes to be specified; e.g. "pr(latex)" will print
  3429 proof state according to the Isabelle LaTeX style;
  3430 
  3431 * Isar: improved support for emulating tactic scripts, including proof
  3432 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3433 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3434 (for HOL datatypes);
  3435 
  3436 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3437 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3438 'proof method scripts' have to be in depth-first order;
  3439 
  3440 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3441 
  3442 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3443 should instead use individual commands for printing items
  3444 (print_commands, print_methods etc.);
  3445 
  3446 * Isar: added 'nothing' --- the empty list of theorems;
  3447 
  3448 
  3449 *** HOL ***
  3450 
  3451 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3452 corresponding virtual machine and a specification of its bytecode
  3453 verifier and a lightweight bytecode verifier, including proofs of
  3454 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3455 Cornelia Pusch (see also the homepage of project Bali at
  3456 http://isabelle.in.tum.de/Bali/);
  3457 
  3458 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3459 Clemens Ballarin;
  3460 
  3461 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3462 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3463 Rasmussen;
  3464 
  3465 * HOL/Lattice: fundamental concepts of lattice theory and order
  3466 structures, including duals, properties of bounds versus algebraic
  3467 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3468 Theorem for complete lattices etc.; may also serve as a demonstration
  3469 for abstract algebraic reasoning using axiomatic type classes, and
  3470 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3471 
  3472 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3473 von Oheimb;
  3474 
  3475 * HOL/IMPP: extension of IMP with local variables and mutually
  3476 recursive procedures, by David von Oheimb;
  3477 
  3478 * HOL/Lambda: converted into new-style theory and document;
  3479 
  3480 * HOL/ex/Multiquote: example of multiple nested quotations and
  3481 anti-quotations -- basically a generalized version of de-Bruijn
  3482 representation; very useful in avoiding lifting of operations;
  3483 
  3484 * HOL/record: added general record equality rule to simpset; fixed
  3485 select-update simplification procedure to handle extended records as
  3486 well; admit "r" as field name;
  3487 
  3488 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3489 other numeric types and also as the identity of groups, rings, etc.;
  3490 
  3491 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3492 Types nat and int belong to this axclass;
  3493 
  3494 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3495    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3496    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3497   two terms #m*u and #n*u are replaced by #(m+n)*u
  3498     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3499   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3500     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3501 
  3502 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3503 powerful prover for predicate logic but knows nothing of clasets; see
  3504 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3505 
  3506 * HOL: new version of "case_tac" subsumes both boolean case split and
  3507 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3508 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3509 
  3510 * HOL: simplification no longer dives into case-expressions: only the
  3511 selector expression is simplified, but not the remaining arms; to
  3512 enable full simplification of case-expressions for datatype t, you may
  3513 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3514 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3515 
  3516 * HOL/recdef: the recursion equations generated by 'recdef' for
  3517 function 'f' are now called f.simps instead of f.rules; if all
  3518 termination conditions are proved automatically, these simplification
  3519 rules are added to the simpset, as in primrec; rules may be named
  3520 individually as well, resulting in a separate list of theorems for
  3521 each equation;
  3522 
  3523 * HOL/While is a new theory that provides a while-combinator. It
  3524 permits the definition of tail-recursive functions without the
  3525 provision of a termination measure. The latter is necessary once the
  3526 invariant proof rule for while is applied.
  3527 
  3528 * HOL: new (overloaded) notation for the set of elements below/above
  3529 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3530 
  3531 * HOL: theorems impI, allI, ballI bound as "strip";
  3532 
  3533 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3534 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3535 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3536 
  3537 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3538 
  3539 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3540 main HOL, but was unused);
  3541 
  3542 * HOL: fewer consts declared as global (e.g. have to refer to
  3543 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3544 
  3545 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3546 in case of overlap with user translations (e.g. judgements over
  3547 tuples); (note that the underlying logical represenation is still
  3548 bogus);
  3549 
  3550 
  3551 *** ZF ***
  3552 
  3553 * ZF: simplification automatically cancels common terms in arithmetic
  3554 expressions over nat and int;
  3555 
  3556 * ZF: new treatment of nat to minimize type-checking: all operators
  3557 coerce their operands to a natural number using the function natify,
  3558 making the algebraic laws unconditional;
  3559 
  3560 * ZF: as above, for int: operators coerce their operands to an integer
  3561 using the function intify;
  3562 
  3563 * ZF: the integer library now contains many of the usual laws for the
  3564 orderings, including $<=, and monotonicity laws for $+ and $*;
  3565 
  3566 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3567 simplification;
  3568 
  3569 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3570 to the simplifier and classical reasoner simultaneously;
  3571 
  3572 
  3573 *** General ***
  3574 
  3575 * Provers: blast_tac now handles actual object-logic rules as
  3576 assumptions; note that auto_tac uses blast_tac internally as well;
  3577 
  3578 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3579 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3580 
  3581 * Provers: delrules now handles destruct rules as well (no longer need
  3582 explicit make_elim);
  3583 
  3584 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3585   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3586 use instead the strong form,
  3587   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3588 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3589 from destruct-rules;
  3590 
  3591 * Provers: Simplifier.easy_setup provides a fast path to basic
  3592 Simplifier setup for new object-logics;
  3593 
  3594 * Pure: AST translation rules no longer require constant head on LHS;
  3595 
  3596 * Pure: improved name spaces: ambiguous output is qualified; support
  3597 for hiding of names;
  3598 
  3599 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3600 XSYMBOL_HOME; no longer need to do manual configuration in most
  3601 situations;
  3602 
  3603 * system: compression of ML heaps images may now be controlled via -c
  3604 option of isabelle and isatool usedir (currently only observed by
  3605 Poly/ML);
  3606 
  3607 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3608 useful for remote X11);
  3609 
  3610 * system: provide TAGS file for Isabelle sources;
  3611 
  3612 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3613 order;
  3614 
  3615 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3616 timing flag supersedes proof_timing and Toplevel.trace;
  3617 
  3618 * ML: new combinators |>> and |>>> for incremental transformations
  3619 with secondary results (e.g. certain theory extensions):
  3620 
  3621 * ML: PureThy.add_defs gets additional argument to indicate potential
  3622 overloading (usually false);
  3623 
  3624 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3625 results;
  3626 
  3627 
  3628 
  3629 New in Isabelle99 (October 1999)
  3630 --------------------------------
  3631 
  3632 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3633 
  3634 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3635 are no longer simplified.  (This allows the simplifier to unfold recursive
  3636 functional programs.)  To restore the old behaviour, declare
  3637 
  3638     Delcongs [if_weak_cong];
  3639 
  3640 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3641 complement;
  3642 
  3643 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3644 
  3645 * HOL/datatype: mutual_induct_tac no longer exists --
  3646   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3647 
  3648 * HOL/typedef: fixed type inference for representing set; type
  3649 arguments now have to occur explicitly on the rhs as type constraints;
  3650 
  3651 * ZF: The con_defs part of an inductive definition may no longer refer
  3652 to constants declared in the same theory;
  3653 
  3654 * HOL, ZF: the function mk_cases, generated by the inductive
  3655 definition package, has lost an argument.  To simplify its result, it
  3656 uses the default simpset instead of a supplied list of theorems.
  3657 
  3658 * HOL/List: the constructors of type list are now Nil and Cons;
  3659 
  3660 * Simplifier: the type of the infix ML functions
  3661         setSSolver addSSolver setSolver addSolver
  3662 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3663 for packaging solvers. A solver is created via
  3664         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3665 where the string argument is only a comment.
  3666 
  3667 
  3668 *** Proof tools ***
  3669 
  3670 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3671 decision procedure for linear arithmetic. Currently it is used for
  3672 types `nat', `int', and `real' in HOL (see below); it can, should and
  3673 will be instantiated for other types and logics as well.
  3674 
  3675 * The simplifier now accepts rewrite rules with flexible heads, eg
  3676      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3677   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3678   matching.
  3679 
  3680 
  3681 *** General ***
  3682 
  3683 * New Isabelle/Isar subsystem provides an alternative to traditional
  3684 tactical theorem proving; together with the ProofGeneral/isar user
  3685 interface it offers an interactive environment for developing human
  3686 readable proof documents (Isar == Intelligible semi-automated
  3687 reasoning); for further information see isatool doc isar-ref,
  3688 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3689 
  3690 * improved and simplified presentation of theories: better HTML markup
  3691 (including colors), graph views in several sizes; isatool usedir now
  3692 provides a proper interface for user theories (via -P option); actual
  3693 document preparation based on (PDF)LaTeX is available as well (for
  3694 new-style theories only); see isatool doc system for more information;
  3695 
  3696 * native support for Proof General, both for classic Isabelle and
  3697 Isabelle/Isar;
  3698 
  3699 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3700 using the graph browser tool;
  3701 
  3702 * Isabelle manuals now also available as PDF;
  3703 
  3704 * theory loader rewritten from scratch (may not be fully
  3705 bug-compatible); old loadpath variable has been replaced by show_path,
  3706 add_path, del_path, reset_path functions; new operations such as
  3707 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3708 isatool doc ref);
  3709 
  3710 * improved isatool install: option -k creates KDE application icon,
  3711 option -p DIR installs standalone binaries;
  3712 
  3713 * added ML_PLATFORM setting (useful for cross-platform installations);
  3714 more robust handling of platform specific ML images for SML/NJ;
  3715 
  3716 * the settings environment is now statically scoped, i.e. it is never
  3717 created again in sub-processes invoked from isabelle, isatool, or
  3718 Isabelle;
  3719 
  3720 * path element specification '~~' refers to '$ISABELLE_HOME';
  3721 
  3722 * in locales, the "assumes" and "defines" parts may be omitted if
  3723 empty;
  3724 
  3725 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3726 long arrows);
  3727 
  3728 * new print_mode "HTML";
  3729 
  3730 * new flag show_tags controls display of tags of theorems (which are
  3731 basically just comments that may be attached by some tools);
  3732 
  3733 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3734 mode and goal output format:
  3735 
  3736 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3737 244c244
  3738 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3739 ---
  3740 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3741 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3742 181c181
  3743 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3744 ---
  3745 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3746 
  3747 * function bind_thms stores lists of theorems (cf. bind_thm);
  3748 
  3749 * new shorthand tactics ftac, eatac, datac, fatac;
  3750 
  3751 * qed (and friends) now accept "" as result name; in that case the
  3752 theorem is not stored, but proper checks and presentation of the
  3753 result still apply;
  3754 
  3755 * theorem database now also indexes constants "Trueprop", "all",
  3756 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3757 
  3758 
  3759 *** HOL ***
  3760 
  3761 ** HOL arithmetic **
  3762 
  3763 * There are now decision procedures for linear arithmetic over nat and
  3764 int:
  3765 
  3766 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3767 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3768 are treated as atomic; subformulae not involving type `nat' or `int'
  3769 are ignored; quantified subformulae are ignored unless they are
  3770 positive universal or negative existential. The tactic has to be
  3771 invoked by hand and can be a little bit slow. In particular, the
  3772 running time is exponential in the number of occurrences of `min' and
  3773 `max', and `-' on `nat'.
  3774 
  3775 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3776 (negated) (in)equalities among the premises and the conclusion into
  3777 account (i.e. no compound formulae) and does not know about `min' and
  3778 `max', and `-' on `nat'. It is fast and is used automatically by the
  3779 simplifier.
  3780 
  3781 NB: At the moment, these decision procedures do not cope with mixed
  3782 nat/int formulae where the two parts interact, such as `m < n ==>
  3783 int(m) < int(n)'.
  3784 
  3785 * HOL/Numeral provides a generic theory of numerals (encoded
  3786 efficiently as bit strings); setup for types nat/int/real is in place;
  3787 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3788 int, existing theories and proof scripts may require a few additional
  3789 type constraints;
  3790 
  3791 * integer division and remainder can now be performed on constant
  3792 arguments;
  3793 
  3794 * many properties of integer multiplication, division and remainder
  3795 are now available;
  3796 
  3797 * An interface to the Stanford Validity Checker (SVC) is available through the
  3798 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3799 are proved automatically.  SVC must be installed separately, and its results
  3800 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3801 invocation of the underlying oracle).  For SVC see
  3802   http://verify.stanford.edu/SVC
  3803 
  3804 * IsaMakefile: the HOL-Real target now builds an actual image;
  3805 
  3806 
  3807 ** HOL misc **
  3808 
  3809 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3810 (in Isabelle/Isar) -- by Gertrud Bauer;
  3811 
  3812 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3813 analysis for assembly languages with subtypes;
  3814 
  3815 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3816 -- avoids syntactic ambiguities and treats state, transition, and
  3817 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3818 changed syntax and (many) tactics;
  3819 
  3820 * HOL/inductive: Now also handles more general introduction rules such
  3821   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3822   theorems are now maintained within the theory (maintained via the
  3823   "mono" attribute);
  3824 
  3825 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3826   (using function types) such as
  3827 
  3828   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3829 
  3830 * HOL/record: record_simproc (part of the default simpset) takes care
  3831 of selectors applied to updated records; record_split_tac is no longer
  3832 part of the default claset; update_defs may now be removed from the
  3833 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3834 
  3835   claset_ref () := claset() addSWrapper record_split_wrapper;
  3836   Delsimprocs [record_simproc]
  3837 
  3838 * HOL/typedef: fixed type inference for representing set; type
  3839 arguments now have to occur explicitly on the rhs as type constraints;
  3840 
  3841 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3842 names rather than an ML expression;
  3843 
  3844 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3845 supplied later.  Program schemes can be defined, such as
  3846     "While B C s = (if B s then While B C (C s) else s)"
  3847 where the well-founded relation can be chosen after B and C have been given.
  3848 
  3849 * HOL/List: the constructors of type list are now Nil and Cons;
  3850 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3851 course, ML tools referring to List.list.op # etc. have to be adapted;
  3852 
  3853 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3854 disabled by default; run isabelle with option -m HOL to get back to
  3855 the original Gordon/HOL-style output;
  3856 
  3857 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3858 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3859 
  3860 * HOL basic syntax simplified (more orthogonal): all variants of
  3861 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3862 Eps operator is provided as well: "SOME x. P[x]";
  3863 
  3864 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3865 
  3866 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3867 thus available for user theories;
  3868 
  3869 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3870 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3871 time;
  3872 
  3873 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3874 several times and then mp;
  3875 
  3876 
  3877 *** LK ***
  3878 
  3879 * the notation <<...>> is now available as a notation for sequences of
  3880 formulas;
  3881 
  3882 * the simplifier is now installed
  3883 
  3884 * the axiom system has been generalized (thanks to Soren Heilmann)
  3885 
  3886 * the classical reasoner now has a default rule database
  3887 
  3888 
  3889 *** ZF ***
  3890 
  3891 * new primrec section allows primitive recursive functions to be given
  3892 directly (as in HOL) over datatypes and the natural numbers;
  3893 
  3894 * new tactics induct_tac and exhaust_tac for induction (or case
  3895 analysis) over datatypes and the natural numbers;
  3896 
  3897 * the datatype declaration of type T now defines the recursor T_rec;
  3898 
  3899 * simplification automatically does freeness reasoning for datatype
  3900 constructors;
  3901 
  3902 * automatic type-inference, with AddTCs command to insert new
  3903 type-checking rules;
  3904 
  3905 * datatype introduction rules are now added as Safe Introduction rules
  3906 to the claset;
  3907 
  3908 * the syntax "if P then x else y" is now available in addition to
  3909 if(P,x,y);
  3910 
  3911 
  3912 *** Internal programming interfaces ***
  3913 
  3914 * tuned simplifier trace output; new flag debug_simp;
  3915 
  3916 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3917 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3918 
  3919 * AxClass.axclass_tac lost the theory argument;
  3920 
  3921 * tuned current_goals_markers semantics: begin / end goal avoids
  3922 printing empty lines;
  3923 
  3924 * removed prs and prs_fn hook, which was broken because it did not
  3925 include \n in its semantics, forcing writeln to add one
  3926 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3927 string -> unit if you really want to output text without newline;
  3928 
  3929 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3930 plain output, interface builders may have to enable 'isabelle_font'
  3931 mode to get Isabelle font glyphs as before;
  3932 
  3933 * refined token_translation interface; INCOMPATIBILITY: output length
  3934 now of type real instead of int;
  3935 
  3936 * theory loader actions may be traced via new ThyInfo.add_hook
  3937 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3938 your own database of information attached to *whole* theories -- as
  3939 opposed to intra-theory data slots offered via TheoryDataFun;
  3940 
  3941 * proper handling of dangling sort hypotheses (at last!);
  3942 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3943 extra sort hypotheses that can be witnessed from the type signature;
  3944 the force_strip_shyps flag is gone, any remaining shyps are simply
  3945 left in the theorem (with a warning issued by strip_shyps_warning);
  3946 
  3947 
  3948 
  3949 New in Isabelle98-1 (October 1998)
  3950 ----------------------------------
  3951 
  3952 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3953 
  3954 * several changes of automated proof tools;
  3955 
  3956 * HOL: major changes to the inductive and datatype packages, including
  3957 some minor incompatibilities of theory syntax;
  3958 
  3959 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3960 called `inj_on';
  3961 
  3962 * HOL: removed duplicate thms in Arith:
  3963   less_imp_add_less  should be replaced by  trans_less_add1
  3964   le_imp_add_le      should be replaced by  trans_le_add1
  3965 
  3966 * HOL: unary minus is now overloaded (new type constraints may be
  3967 required);
  3968 
  3969 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3970 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3971 now taken as an integer constant.
  3972 
  3973 * Pure: ML function 'theory_of' renamed to 'theory';
  3974 
  3975 
  3976 *** Proof tools ***
  3977 
  3978 * Simplifier:
  3979   1. Asm_full_simp_tac is now more aggressive.
  3980      1. It will sometimes reorient premises if that increases their power to
  3981         simplify.
  3982      2. It does no longer proceed strictly from left to right but may also
  3983         rotate premises to achieve further simplification.
  3984      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3985      old Asm_full_simp_tac in that it does not rotate premises.
  3986   2. The simplifier now knows a little bit about nat-arithmetic.
  3987 
  3988 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3989 allows for selected deletion of wrappers, by introduction of names for
  3990 wrapper functionals.  This implies that addbefore, addSbefore,
  3991 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3992 and that adding two tactics with the same name overwrites the first
  3993 one (emitting a warning).
  3994   type wrapper = (int -> tactic) -> (int -> tactic)
  3995   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3996   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3997   delWrapper, delSWrapper: claset *  string            -> claset
  3998   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3999 
  4000 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4001 semantics; addbefore now affects only the unsafe part of step_tac
  4002 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4003 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4004 by Force_tac;
  4005 
  4006 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4007 compWrapper; added safe wrapper (and access functions for it);
  4008 
  4009 * HOL/split_all_tac is now much faster and fails if there is nothing
  4010 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4011 and the names of the automatically generated variables have changed.
  4012 split_all_tac has moved within claset() from unsafe wrappers to safe
  4013 wrappers, which means that !!-bound variables are split much more
  4014 aggressively, and safe_tac and clarify_tac now split such variables.
  4015 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4016 Note: the same holds for record_split_tac, which does the job of
  4017 split_all_tac for record fields.
  4018 
  4019 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4020 permanently to the default simpset using Addsplits just like
  4021 Addsimps. They can be removed via Delsplits just like
  4022 Delsimps. Lower-case versions are also available.
  4023 
  4024 * HOL/Simplifier: The rule split_if is now part of the default
  4025 simpset. This means that the simplifier will eliminate all occurrences
  4026 of if-then-else in the conclusion of a goal. To prevent this, you can
  4027 either remove split_if completely from the default simpset by
  4028 `Delsplits [split_if]' or remove it in a specific call of the
  4029 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4030 other case splitting rules to/from the default simpset: every datatype
  4031 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4032 t is the name of the datatype).
  4033 
  4034 * Classical reasoner / Simplifier combination: new force_tac (and
  4035 derivatives Force_tac, force) combines rewriting and classical
  4036 reasoning (and whatever other tools) similarly to auto_tac, but is
  4037 aimed to solve the given subgoal completely.
  4038 
  4039 
  4040 *** General ***
  4041 
  4042 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4043 and `goalw': the theory is no longer needed as an explicit argument -
  4044 the current theory context is used; assumptions are no longer returned
  4045 at the ML-level unless one of them starts with ==> or !!; it is
  4046 recommended to convert to these new commands using isatool fixgoal
  4047 (backup your sources first!);
  4048 
  4049 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4050 the current theory context, and 'theory' to lookup stored theories;
  4051 
  4052 * new theory section 'locale' for declaring constants, assumptions and
  4053 definitions that have local scope;
  4054 
  4055 * new theory section 'nonterminals' for purely syntactic types;
  4056 
  4057 * new theory section 'setup' for generic ML setup functions
  4058 (e.g. package initialization);
  4059 
  4060 * the distribution now includes Isabelle icons: see
  4061 lib/logo/isabelle-{small,tiny}.xpm;
  4062 
  4063 * isatool install - install binaries with absolute references to
  4064 ISABELLE_HOME/bin;
  4065 
  4066 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4067 
  4068 * print mode 'emacs' reserved for Isamode;
  4069 
  4070 * support multiple print (ast) translations per constant name;
  4071 
  4072 * theorems involving oracles are now printed with a suffixed [!];
  4073 
  4074 
  4075 *** HOL ***
  4076 
  4077 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4078 
  4079 * HOL/inductive package reorganized and improved: now supports mutual
  4080 definitions such as
  4081 
  4082   inductive EVEN ODD
  4083     intrs
  4084       null "0 : EVEN"
  4085       oddI "n : EVEN ==> Suc n : ODD"
  4086       evenI "n : ODD ==> Suc n : EVEN"
  4087 
  4088 new theorem list "elims" contains an elimination rule for each of the
  4089 recursive sets; inductive definitions now handle disjunctive premises
  4090 correctly (also ZF);
  4091 
  4092 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4093 "mutual_induct" no longer exists - the induction rule is always
  4094 contained in "induct";
  4095 
  4096 
  4097 * HOL/datatype package re-implemented and greatly improved: now
  4098 supports mutually recursive datatypes such as
  4099 
  4100   datatype
  4101     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4102             | SUM ('a aexp) ('a aexp)
  4103             | DIFF ('a aexp) ('a aexp)
  4104             | NUM 'a
  4105   and
  4106     'a bexp = LESS ('a aexp) ('a aexp)
  4107             | AND ('a bexp) ('a bexp)
  4108             | OR ('a bexp) ('a bexp)
  4109 
  4110 as well as indirectly recursive datatypes such as
  4111 
  4112   datatype
  4113     ('a, 'b) term = Var 'a
  4114                   | App 'b ((('a, 'b) term) list)
  4115 
  4116 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4117 induction on mutually / indirectly recursive datatypes.
  4118 
  4119 Primrec equations are now stored in theory and can be accessed via
  4120 <function_name>.simps.
  4121 
  4122 INCOMPATIBILITIES:
  4123 
  4124   - Theories using datatypes must now have theory Datatype as an
  4125     ancestor.
  4126   - The specific <typename>.induct_tac no longer exists - use the
  4127     generic induct_tac instead.
  4128   - natE has been renamed to nat.exhaust - use exhaust_tac
  4129     instead of res_inst_tac ... natE. Note that the variable
  4130     names in nat.exhaust differ from the names in natE, this
  4131     may cause some "fragile" proofs to fail.
  4132   - The theorems split_<typename>_case and split_<typename>_case_asm
  4133     have been renamed to <typename>.split and <typename>.split_asm.
  4134   - Since default sorts of type variables are now handled correctly,
  4135     some datatype definitions may have to be annotated with explicit
  4136     sort constraints.
  4137   - Primrec definitions no longer require function name and type
  4138     of recursive argument.
  4139 
  4140 Consider using isatool fixdatatype to adapt your theories and proof
  4141 scripts to the new package (backup your sources first!).
  4142 
  4143 
  4144 * HOL/record package: considerably improved implementation; now
  4145 includes concrete syntax for record types, terms, updates; theorems
  4146 for surjective pairing and splitting !!-bound record variables; proof
  4147 support is as follows:
  4148 
  4149   1) standard conversions (selectors or updates applied to record
  4150 constructor terms) are part of the standard simpset;
  4151 
  4152   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4153 made part of standard simpset and claset via addIffs;
  4154 
  4155   3) a tactic for record field splitting (record_split_tac) is part of
  4156 the standard claset (addSWrapper);
  4157 
  4158 To get a better idea about these rules you may retrieve them via
  4159 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4160 the name of your record type.
  4161 
  4162 The split tactic 3) conceptually simplifies by the following rule:
  4163 
  4164   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4165 
  4166 Thus any record variable that is bound by meta-all will automatically
  4167 blow up into some record constructor term, consequently the
  4168 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4169 solve record problems automatically.
  4170 
  4171 
  4172 * reorganized the main HOL image: HOL/Integ and String loaded by
  4173 default; theory Main includes everything;
  4174 
  4175 * automatic simplification of integer sums and comparisons, using cancellation;
  4176 
  4177 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4178 
  4179 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4180 
  4181 * many new identities for unions, intersections, set difference, etc.;
  4182 
  4183 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4184 called split_if, split_split, split_sum_case and split_nat_case (to go
  4185 with add/delsplits);
  4186 
  4187 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4188 (?x::unit) = (); this is made part of the default simpset, which COULD
  4189 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4190 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4191 unit_abs_eta_conv is added in order to counter the effect of
  4192 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4193 %u.f();
  4194 
  4195 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4196 makes more sense);
  4197 
  4198 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4199   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4200   disjointness reasoning but breaking a few old proofs.
  4201 
  4202 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4203 to 'converse' from 'inverse' (for compatibility with ZF and some
  4204 literature);
  4205 
  4206 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4207 the well-founded relation;
  4208 
  4209 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4210     Compl A.  The "Compl" syntax remains available as input syntax for this
  4211     release ONLY.
  4212 
  4213 * HOL/Update: new theory of function updates:
  4214     f(a:=b) == %x. if x=a then b else f x
  4215 may also be iterated as in f(a:=b,c:=d,...);
  4216 
  4217 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4218 
  4219 * HOL/List:
  4220   - new function list_update written xs[i:=v] that updates the i-th
  4221     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4222   - new function `upt' written [i..j(] which generates the list
  4223     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4224     bound write [i..j], which is a shorthand for [i..j+1(].
  4225   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4226 
  4227 * HOL/Arith:
  4228   - removed 'pred' (predecessor) function;
  4229   - generalized some theorems about n-1;
  4230   - many new laws about "div" and "mod";
  4231   - new laws about greatest common divisors (see theory ex/Primes);
  4232 
  4233 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4234 instead of "inverse";
  4235 
  4236 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4237   of the multiset ordering;
  4238 
  4239 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4240   (not included by default);
  4241 
  4242 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4243 
  4244 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4245   programs, i.e. different program variables may have different types.
  4246 
  4247 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4248   [previously, this check worked only if the rewrite rule was unconditional]
  4249   Now rew can involve either definitions or equalities (either == or =).
  4250 
  4251 
  4252 *** ZF ***
  4253 
  4254 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4255   only the theorems proved on ZF.ML;
  4256 
  4257 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4258   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4259   disjointness reasoning but breaking a few old proofs.
  4260 
  4261 * ZF/Update: new theory of function updates
  4262     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4263   may also be iterated as in f(a:=b,c:=d,...);
  4264 
  4265 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4266 
  4267 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4268   [previously, this check worked only if the rewrite rule was unconditional]
  4269   Now rew can involve either definitions or equalities (either == or =).
  4270 
  4271 * case_tac provided for compatibility with HOL
  4272     (like the old excluded_middle_tac, but with subgoals swapped)
  4273 
  4274 
  4275 *** Internal programming interfaces ***
  4276 
  4277 * Pure: several new basic modules made available for general use, see
  4278 also src/Pure/README;
  4279 
  4280 * improved the theory data mechanism to support encapsulation (data
  4281 kind name replaced by private Object.kind, acting as authorization
  4282 key); new type-safe user interface via functor TheoryDataFun; generic
  4283 print_data function becomes basically useless;
  4284 
  4285 * removed global_names compatibility flag -- all theory declarations
  4286 are qualified by default;
  4287 
  4288 * module Pure/Syntax now offers quote / antiquote translation
  4289 functions (useful for Hoare logic etc. with implicit dependencies);
  4290 see HOL/ex/Antiquote for an example use;
  4291 
  4292 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4293 cterm -> thm;
  4294 
  4295 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4296 subgoal;
  4297 
  4298 * Display.print_goals function moved to Locale.print_goals;
  4299 
  4300 * standard print function for goals supports current_goals_markers
  4301 variable for marking begin of proof, end of proof, start of goal; the
  4302 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4303 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4304 for example;
  4305 
  4306 
  4307 
  4308 New in Isabelle98 (January 1998)
  4309 --------------------------------
  4310 
  4311 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4312 
  4313 * changed lexical syntax of terms / types: dots made part of long
  4314 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4315 
  4316 * simpset (and claset) reference variable replaced by functions
  4317 simpset / simpset_ref;
  4318 
  4319 * no longer supports theory aliases (via merge) and non-trivial
  4320 implicit merge of thms' signatures;
  4321 
  4322 * most internal names of constants changed due to qualified names;
  4323 
  4324 * changed Pure/Sequence interface (see Pure/seq.ML);
  4325 
  4326 
  4327 *** General Changes ***
  4328 
  4329 * hierachically structured name spaces (for consts, types, axms, thms
  4330 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4331 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4332 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4333 long_names for fully qualified output names; NOTE: ML programs
  4334 (special tactics, packages etc.) referring to internal names may have
  4335 to be adapted to cope with fully qualified names; in case of severe
  4336 backward campatibility problems try setting 'global_names' at compile
  4337 time to have enrything declared within a flat name space; one may also
  4338 fine tune name declarations in theories via the 'global' and 'local'
  4339 section;
  4340 
  4341 * reimplemented the implicit simpset and claset using the new anytype
  4342 data filed in signatures; references simpset:simpset ref etc. are
  4343 replaced by functions simpset:unit->simpset and
  4344 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4345 to patch your ML files accordingly;
  4346 
  4347 * HTML output now includes theory graph data for display with Java
  4348 applet or isatool browser; data generated automatically via isatool
  4349 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4350 
  4351 * defs may now be conditional; improved rewrite_goals_tac to handle
  4352 conditional equations;
  4353 
  4354 * defs now admits additional type arguments, using TYPE('a) syntax;
  4355 
  4356 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4357 creates a new theory node; implicit merge of thms' signatures is
  4358 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4359 transfer:theory->thm->thm in (rare) cases;
  4360 
  4361 * improved handling of draft signatures / theories; draft thms (and
  4362 ctyps, cterms) are automatically promoted to real ones;
  4363 
  4364 * slightly changed interfaces for oracles: admit many per theory, named
  4365 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4366 
  4367 * print_goals: optional output of const types (set show_consts and
  4368 show_types);
  4369 
  4370 * improved output of warnings (###) and errors (***);
  4371 
  4372 * subgoal_tac displays a warning if the new subgoal has type variables;
  4373 
  4374 * removed old README and Makefiles;
  4375 
  4376 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4377 
  4378 * removed obsolete init_pps and init_database;
  4379 
  4380 * deleted the obsolete tactical STATE, which was declared by
  4381     fun STATE tacfun st = tacfun st st;
  4382 
  4383 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4384 (which abbreviates $HOME);
  4385 
  4386 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4387 use isatool fixseq to adapt your ML programs (this works for fully
  4388 qualified references to the Sequence structure only!);
  4389 
  4390 * use_thy no longer requires writable current directory; it always
  4391 reloads .ML *and* .thy file, if either one is out of date;
  4392 
  4393 
  4394 *** Classical Reasoner ***
  4395 
  4396 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4397 tactics that use classical reasoning to simplify a subgoal without
  4398 splitting it into several subgoals;
  4399 
  4400 * Safe_tac: like safe_tac but uses the default claset;
  4401 
  4402 
  4403 *** Simplifier ***
  4404 
  4405 * added simplification meta rules:
  4406     (asm_)(full_)simplify: simpset -> thm -> thm;
  4407 
  4408 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4409 logics (again);
  4410 
  4411 * added prems argument to simplification procedures;
  4412 
  4413 * HOL, FOL, ZF: added infix function `addsplits':
  4414   instead of `<simpset> setloop (split_tac <thms>)'
  4415   you can simply write `<simpset> addsplits <thms>'
  4416 
  4417 
  4418 *** Syntax ***
  4419 
  4420 * TYPE('a) syntax for type reflection terms;
  4421 
  4422 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4423 
  4424 * pretty printer: changed order of mixfix annotation preference (again!);
  4425 
  4426 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4427 
  4428 
  4429 *** HOL ***
  4430 
  4431 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4432   with `addloop' of the simplifier to faciliate case splitting in premises.
  4433 
  4434 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4435 
  4436 * HOL/Auth: new protocol proofs including some for the Internet
  4437   protocol TLS;
  4438 
  4439 * HOL/Map: new theory of `maps' a la VDM;
  4440 
  4441 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4442 cancelling out common nat summands from =, <, <= (in)equalities, or
  4443 differences; simplification procedures nat_cancel_factor for
  4444 cancelling common factor from =, <, <= (in)equalities over natural
  4445 sums; nat_cancel contains both kinds of procedures, it is installed by
  4446 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4447 
  4448 * HOL/simplifier: terms of the form
  4449   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4450   are rewritten to
  4451   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4452   and those of the form
  4453   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4454   are rewritten to
  4455   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4456 
  4457 * HOL/datatype
  4458   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4459 
  4460   P(t_case f1 ... fn x) =
  4461      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4462         ...
  4463        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4464      )
  4465 
  4466   and a theorem `split_t_case_asm' of the form
  4467 
  4468   P(t_case f1 ... fn x) =
  4469     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4470         ...
  4471        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4472      )
  4473   which can be added to a simpset via `addsplits'. The existing theorems
  4474   expand_list_case and expand_option_case have been renamed to
  4475   split_list_case and split_option_case.
  4476 
  4477 * HOL/Arithmetic:
  4478   - `pred n' is automatically converted to `n-1'.
  4479     Users are strongly encouraged not to use `pred' any longer,
  4480     because it will disappear altogether at some point.
  4481   - Users are strongly encouraged to write "0 < n" rather than
  4482     "n ~= 0". Theorems and proof tools have been modified towards this
  4483     `standard'.
  4484 
  4485 * HOL/Lists:
  4486   the function "set_of_list" has been renamed "set" (and its theorems too);
  4487   the function "nth" now takes its arguments in the reverse order and
  4488   has acquired the infix notation "!" as in "xs!n".
  4489 
  4490 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4491 
  4492 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4493   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4494 
  4495 * HOL/record: extensible records with schematic structural subtyping
  4496 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4497 still lacks various theorems and concrete record syntax;
  4498 
  4499 
  4500 *** HOLCF ***
  4501 
  4502 * removed "axioms" and "generated by" sections;
  4503 
  4504 * replaced "ops" section by extended "consts" section, which is capable of
  4505   handling the continuous function space "->" directly;
  4506 
  4507 * domain package:
  4508   . proves theorems immediately and stores them in the theory,
  4509   . creates hierachical name space,
  4510   . now uses normal mixfix annotations (instead of cinfix...),
  4511   . minor changes to some names and values (for consistency),
  4512   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4513   . separator between mutual domain defs: changed "," to "and",
  4514   . improved handling of sort constraints;  now they have to
  4515     appear on the left-hand side of the equations only;
  4516 
  4517 * fixed LAM <x,y,zs>.b syntax;
  4518 
  4519 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4520 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4521 
  4522 
  4523 *** FOL and ZF ***
  4524 
  4525 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4526   with `addloop' of the simplifier to faciliate case splitting in premises.
  4527 
  4528 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4529 in HOL, they strip ALL and --> from proved theorems;
  4530 
  4531 
  4532 
  4533 New in Isabelle94-8 (May 1997)
  4534 ------------------------------
  4535 
  4536 *** General Changes ***
  4537 
  4538 * new utilities to build / run / maintain Isabelle etc. (in parts
  4539 still somewhat experimental); old Makefiles etc. still functional;
  4540 
  4541 * new 'Isabelle System Manual';
  4542 
  4543 * INSTALL text, together with ./configure and ./build scripts;
  4544 
  4545 * reimplemented type inference for greater efficiency, better error
  4546 messages and clean internal interface;
  4547 
  4548 * prlim command for dealing with lots of subgoals (an easier way of
  4549 setting goals_limit);
  4550 
  4551 
  4552 *** Syntax ***
  4553 
  4554 * supports alternative (named) syntax tables (parser and pretty
  4555 printer); internal interface is provided by add_modesyntax(_i);
  4556 
  4557 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4558 be used in conjunction with the Isabelle symbol font; uses the
  4559 "symbols" syntax table;
  4560 
  4561 * added token_translation interface (may translate name tokens in
  4562 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4563 the current print_mode); IMPORTANT: user print translation functions
  4564 are responsible for marking newly introduced bounds
  4565 (Syntax.mark_boundT);
  4566 
  4567 * token translations for modes "xterm" and "xterm_color" that display
  4568 names in bold, underline etc. or colors (which requires a color
  4569 version of xterm);
  4570 
  4571 * infixes may now be declared with names independent of their syntax;
  4572 
  4573 * added typed_print_translation (like print_translation, but may
  4574 access type of constant);
  4575 
  4576 
  4577 *** Classical Reasoner ***
  4578 
  4579 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4580 some limitations.  Blast_tac...
  4581   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4582   + ignores elimination rules that don't have the correct format
  4583         (the conclusion MUST be a formula variable)
  4584   + ignores types, which can make HOL proofs fail
  4585   + rules must not require higher-order unification, e.g. apply_type in ZF
  4586     [message "Function Var's argument not a bound variable" relates to this]
  4587   + its proof strategy is more general but can actually be slower
  4588 
  4589 * substitution with equality assumptions no longer permutes other
  4590 assumptions;
  4591 
  4592 * minor changes in semantics of addafter (now called addaltern); renamed
  4593 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4594 (and access functions for it);
  4595 
  4596 * improved combination of classical reasoner and simplifier:
  4597   + functions for handling clasimpsets
  4598   + improvement of addss: now the simplifier is called _after_ the
  4599     safe steps.
  4600   + safe variant of addss called addSss: uses safe simplifications
  4601     _during_ the safe steps. It is more complete as it allows multiple
  4602     instantiations of unknowns (e.g. with slow_tac).
  4603 
  4604 *** Simplifier ***
  4605 
  4606 * added interface for simplification procedures (functions that
  4607 produce *proven* rewrite rules on the fly, depending on current
  4608 redex);
  4609 
  4610 * ordering on terms as parameter (used for ordered rewriting);
  4611 
  4612 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4613 
  4614 * the solver is now split into a safe and an unsafe part.
  4615 This should be invisible for the normal user, except that the
  4616 functions setsolver and addsolver have been renamed to setSolver and
  4617 addSolver; added safe_asm_full_simp_tac;
  4618 
  4619 
  4620 *** HOL ***
  4621 
  4622 * a generic induction tactic `induct_tac' which works for all datatypes and
  4623 also for type `nat';
  4624 
  4625 * a generic case distinction tactic `exhaust_tac' which works for all
  4626 datatypes and also for type `nat';
  4627 
  4628 * each datatype comes with a function `size';
  4629 
  4630 * patterns in case expressions allow tuple patterns as arguments to
  4631 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4632 
  4633 * primrec now also works with type nat;
  4634 
  4635 * recdef: a new declaration form, allows general recursive functions to be
  4636 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4637 
  4638 * the constant for negation has been renamed from "not" to "Not" to
  4639 harmonize with FOL, ZF, LK, etc.;
  4640 
  4641 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4642 infinite lists;
  4643 
  4644 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4645 
  4646 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4647 problems in commutative rings, using axiomatic type classes for + and *;
  4648 
  4649 * more examples in HOL/MiniML and HOL/Auth;
  4650 
  4651 * more default rewrite rules for quantifiers, union/intersection;
  4652 
  4653 * a new constant `arbitrary == @x.False';
  4654 
  4655 * HOLCF/IOA replaces old HOL/IOA;
  4656 
  4657 * HOLCF changes: derived all rules and arities
  4658   + axiomatic type classes instead of classes
  4659   + typedef instead of faking type definitions
  4660   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4661   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4662   + eliminated the types void, one, tr
  4663   + use unit lift and bool lift (with translations) instead of one and tr
  4664   + eliminated blift from Lift3.thy (use Def instead of blift)
  4665   all eliminated rules are derived as theorems --> no visible changes ;
  4666 
  4667 
  4668 *** ZF ***
  4669 
  4670 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4671 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4672 as ZF_cs addSIs [equalityI];
  4673 
  4674 
  4675 
  4676 New in Isabelle94-7 (November 96)
  4677 ---------------------------------
  4678 
  4679 * allowing negative levels (as offsets) in prlev and choplev;
  4680 
  4681 * super-linear speedup for large simplifications;
  4682 
  4683 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4684 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4685 FAIL); can suppress it using the command Delsimps (ex_simps @
  4686 all_simps); De Morgan laws are also now included, by default;
  4687 
  4688 * improved printing of ==>  :  ~:
  4689 
  4690 * new object-logic "Sequents" adds linear logic, while replacing LK
  4691 and Modal (thanks to Sara Kalvala);
  4692 
  4693 * HOL/Auth: correctness proofs for authentication protocols;
  4694 
  4695 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4696 examples on HOL/Auth);
  4697 
  4698 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4699 the rewriter and classical reasoner simultaneously;
  4700 
  4701 * function uresult no longer returns theorems in "standard" format;
  4702 regain previous version by: val uresult = standard o uresult;
  4703 
  4704 
  4705 
  4706 New in Isabelle94-6
  4707 -------------------
  4708 
  4709 * oracles -- these establish an interface between Isabelle and trusted
  4710 external reasoners, which may deliver results as theorems;
  4711 
  4712 * proof objects (in particular record all uses of oracles);
  4713 
  4714 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4715 
  4716 * "constdefs" section in theory files;
  4717 
  4718 * "primrec" section (HOL) no longer requires names;
  4719 
  4720 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4721 
  4722 
  4723 
  4724 New in Isabelle94-5
  4725 -------------------
  4726 
  4727 * reduced space requirements;
  4728 
  4729 * automatic HTML generation from theories;
  4730 
  4731 * theory files no longer require "..." (quotes) around most types;
  4732 
  4733 * new examples, including two proofs of the Church-Rosser theorem;
  4734 
  4735 * non-curried (1994) version of HOL is no longer distributed;
  4736 
  4737 
  4738 
  4739 New in Isabelle94-4
  4740 -------------------
  4741 
  4742 * greatly reduced space requirements;
  4743 
  4744 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4745 
  4746 * searchable theorem database (see the section "Retrieving theorems" on
  4747 page 8 of the Reference Manual);
  4748 
  4749 * new examples, including Grabczewski's monumental case study of the
  4750 Axiom of Choice;
  4751 
  4752 * The previous version of HOL renamed to Old_HOL;
  4753 
  4754 * The new version of HOL (previously called CHOL) uses a curried syntax
  4755 for functions.  Application looks like f a b instead of f(a,b);
  4756 
  4757 * Mutually recursive inductive definitions finally work in HOL;
  4758 
  4759 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4760 translates to the operator "split";
  4761 
  4762 
  4763 
  4764 New in Isabelle94-3
  4765 -------------------
  4766 
  4767 * new infix operator, addss, allowing the classical reasoner to
  4768 perform simplification at each step of its search.  Example:
  4769         fast_tac (cs addss ss)
  4770 
  4771 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4772 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4773 look like (a,b) instead of <a,b>;
  4774 
  4775 * PLEASE NOTE: CHOL will eventually replace HOL!
  4776 
  4777 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4778 It translates to the operator "split".  A new theory of integers is available;
  4779 
  4780 * In ZF, integer numerals now denote two's-complement binary integers.
  4781 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4782 
  4783 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4784 of the Axiom of Choice;
  4785 
  4786 
  4787 
  4788 New in Isabelle94-2
  4789 -------------------
  4790 
  4791 * Significantly faster resolution;
  4792 
  4793 * the different sections in a .thy file can now be mixed and repeated
  4794 freely;
  4795 
  4796 * Database of theorems for FOL, HOL and ZF.  New
  4797 commands including qed, qed_goal and bind_thm store theorems in the database.
  4798 
  4799 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4800 a given theory (thms_of), or find out what theory a theorem was proved in
  4801 (theory_of_thm);
  4802 
  4803 * Bugs fixed in the inductive definition and datatype packages;
  4804 
  4805 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4806 and HOL_dup_cs obsolete;
  4807 
  4808 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4809 have been removed;
  4810 
  4811 * Simpler definition of function space in ZF;
  4812 
  4813 * new results about cardinal and ordinal arithmetic in ZF;
  4814 
  4815 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4816 types;
  4817 
  4818 
  4819 $Id$