NEWS
author haftmann
Wed Feb 14 10:06:12 2007 +0100 (2007-02-14)
changeset 22316 f662831459de
parent 22218 30a8890d2967
child 22376 b711c2ad7507
permissions -rw-r--r--
added class "preorder"
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: some popular names (e.g. "class", "fun", "help",
    19 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    20 
    21 * Legacy goal package: reduced interface to the bare minimum required
    22 to keep existing proof scripts running.  Most other user-level
    23 functions are now part of the OldGoals structure, which is *not* open
    24 by default (consider isatool expandshort before open OldGoals).
    25 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    26 these tend to cause confusion about the actual goal (!) context being
    27 used here, which is not necessarily the same as the_context().
    28 
    29 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    30 
    31 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    32 by default, which means that "prems" (and also "fixed variables") are
    33 suppressed from proof state output.  Note that the ProofGeneral
    34 settings mechanism allows to change and save options persistently, but
    35 older versions of Isabelle will fail to start up if a negative prems
    36 limit is imposed.
    37 
    38 * Local theory targets may be specified by non-nested blocks of
    39 ``context/locale/class ... begin'' followed by ``end''.  The body may
    40 contain definitions, theorems etc., including any derived mechanism
    41 that has been implemented on top of these primitives.  This concept
    42 generalizes the existing ``theorem (in ...)'' towards more versatility
    43 and scalability.
    44 
    45 * Proof General interface: proper undo of final 'end' command;
    46 discontinued Isabelle/classic mode (ML proof scripts).
    47 
    48 
    49 *** Document preparation ***
    50 
    51 * Added antiquotation @{theory name} which prints the given name,
    52 after checking that it refers to a valid ancestor theory in the
    53 current context.
    54 
    55 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    56 check the given source text as ML type/structure, printing verbatim.
    57 
    58 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    59 "c args == rhs" given in the current context.  (Any number of
    60 arguments may be given on the LHS.)
    61 
    62 
    63 
    64 *** Pure ***
    65 
    66 * class_package.ML offers a combination of axclasses and locales to
    67 achieve Haskell-like type classes in Isabelle. See
    68 HOL/ex/Classpackage.thy for examples.
    69 
    70 * Yet another code generator framework allows to generate executable
    71 code for ML and Haskell (including "class"es). A short usage sketch:
    72 
    73     internal compilation:
    74         code_gen <list of constants (term syntax)> (SML #)
    75     writing SML code to a file:
    76         code_gen <list of constants (term syntax)> (SML <filename>)
    77     writing Haskell code to a bunch of files:
    78         code_gen <list of constants (term syntax)> (Haskell <filename>)
    79 
    80 Reasonable default setup of framework in HOL/Main.
    81 
    82 Theorem attributs for selecting and transforming function equations theorems:
    83 
    84     [code fun]:       select a theorem as function equation for a specific constant
    85     [code nofun]:     deselect a theorem as function equation for a specific constant
    86     [code inline]:    select an equation theorem for unfolding (inlining) in place
    87     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    88 
    89 User-defined serializations (target in {SML, Haskell}):
    90 
    91     code_const <and-list of constants (term syntax)>
    92       {(target) <and-list of const target syntax>}+
    93 
    94     code_type <and-list of type constructors>
    95       {(target) <and-list of type target syntax>}+
    96 
    97     code_instance <and-list of instances>
    98       {(target)}+
    99         where instance ::= <type constructor> :: <class>
   100 
   101     code_class <and_list of classes>
   102       {(target) <and-list of class target syntax>}+
   103         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   104 
   105 For code_instance and code_class, target SML is silently ignored.
   106 
   107 See HOL theories and HOL/ex/Code*.thy for usage examples.  Doc/Isar/Advanced/Codegen/
   108 provides a tutorial.
   109 
   110 * Command 'no_translations' removes translation rules from theory
   111 syntax.
   112 
   113 * Overloaded definitions are now actually checked for acyclic
   114 dependencies.  The overloading scheme is slightly more general than
   115 that of Haskell98, although Isabelle does not demand an exact
   116 correspondence to type class and instance declarations.
   117 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   118 exotic versions of overloading -- at the discretion of the user!
   119 
   120 Polymorphic constants are represented via type arguments, i.e. the
   121 instantiation that matches an instance against the most general
   122 declaration given in the signature.  For example, with the declaration
   123 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   124 as c(nat).  Overloading is essentially simultaneous structural
   125 recursion over such type arguments.  Incomplete specification patterns
   126 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   127 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   128 Command 'print_theory' outputs the normalized system of recursive
   129 equations, see section "definitions".
   130 
   131 * Isar: improper proof element 'guess' is like 'obtain', but derives
   132 the obtained context from the course of reasoning!  For example:
   133 
   134   assume "EX x y. A x & B y"   -- "any previous fact"
   135   then guess x and y by clarify
   136 
   137 This technique is potentially adventurous, depending on the facts and
   138 proof tools being involved here.
   139 
   140 * Isar: known facts from the proof context may be specified as literal
   141 propositions, using ASCII back-quote syntax.  This works wherever
   142 named facts used to be allowed so far, in proof commands, proof
   143 methods, attributes etc.  Literal facts are retrieved from the context
   144 according to unification of type and term parameters.  For example,
   145 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   146 theorems in the current context, then these are valid literal facts:
   147 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   148 
   149 There is also a proof method "fact" which does the same composition
   150 for explicit goal states, e.g. the following proof texts coincide with
   151 certain special cases of literal facts:
   152 
   153   have "A" by fact                 ==  note `A`
   154   have "A ==> B" by fact           ==  note `A ==> B`
   155   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   156   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   157 
   158 * Isar: ":" (colon) is no longer a symbolic identifier character in
   159 outer syntax.  Thus symbolic identifiers may be used without
   160 additional white space in declarations like this: ``assume *: A''.
   161 
   162 * Isar: 'print_facts' prints all local facts of the current context,
   163 both named and unnamed ones.
   164 
   165 * Isar: 'def' now admits simultaneous definitions, e.g.:
   166 
   167   def x == "t" and y == "u"
   168 
   169 * Isar: added command 'unfolding', which is structurally similar to
   170 'using', but affects both the goal state and facts by unfolding given
   171 rewrite rules.  Thus many occurrences of the 'unfold' method or
   172 'unfolded' attribute may be replaced by first-class proof text.
   173 
   174 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   175 and command 'unfolding' now all support object-level equalities
   176 (potentially conditional).  The underlying notion of rewrite rule is
   177 analogous to the 'rule_format' attribute, but *not* that of the
   178 Simplifier (which is usually more generous).
   179 
   180 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   181 method expression within a sandbox consisting of the first N
   182 sub-goals, which need to exist.  For example, ``simp_all [3]''
   183 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   184 simplifies all new goals that emerge from applying rule foo to the
   185 originally first one.
   186 
   187 * Isar: schematic goals are no longer restricted to higher-order
   188 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   189 expected.
   190 
   191 * Isar: the conclusion of a long theorem statement is now either
   192 'shows' (a simultaneous conjunction, as before), or 'obtains'
   193 (essentially a disjunction of cases with local parameters and
   194 assumptions).  The latter allows to express general elimination rules
   195 adequately; in this notation common elimination rules look like this:
   196 
   197   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   198     assumes "EX x. P x"
   199     obtains x where "P x"
   200 
   201   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   202     assumes "A & B"
   203     obtains A and B
   204 
   205   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   206     assumes "A | B"
   207     obtains
   208       A
   209     | B
   210 
   211 The subsequent classical rules even refer to the formal "thesis"
   212 explicitly:
   213 
   214   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   215     obtains "~ thesis"
   216 
   217   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   218     obtains "thesis ==> something"
   219 
   220 The actual proof of an 'obtains' statement is analogous to that of the
   221 Isar proof element 'obtain', only that there may be several cases.
   222 Optional case names may be specified in parentheses; these will be
   223 available both in the present proof and as annotations in the
   224 resulting rule, for later use with the 'cases' method (cf. attribute
   225 case_names).
   226 
   227 * Isar: the assumptions of a long theorem statement are available as
   228 "assms" fact in the proof context.  This is more appropriate than the
   229 (historical) "prems", which refers to all assumptions of the current
   230 context, including those from the target locale, proof body etc.
   231 
   232 * Isar: 'print_statement' prints theorems from the current theory or
   233 proof context in long statement form, according to the syntax of a
   234 top-level lemma.
   235 
   236 * Isar: 'obtain' takes an optional case name for the local context
   237 introduction rule (default "that").
   238 
   239 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   240 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   241 to occur.
   242 
   243 * Pure: syntax "CONST name" produces a fully internalized constant
   244 according to the current context.  This is particularly useful for
   245 syntax translations that should refer to internal constant
   246 representations independently of name spaces.
   247 
   248 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   249 instead of "FOO ". This allows multiple binder declarations to coexist
   250 in the same context.  INCOMPATIBILITY.
   251 
   252 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   253 primitive that also works in a locale context (both for constants and
   254 fixed variables).  Type declaration and internal syntactic
   255 representation of given constants retrieved from the context.
   256 
   257 * Isar/locales: new derived specification elements 'axiomatization',
   258 'definition', 'abbreviation', which support type-inference, admit
   259 object-level specifications (equality, equivalence).  See also the
   260 isar-ref manual.  Examples:
   261 
   262   axiomatization
   263     eq  (infix "===" 50) where
   264     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   265 
   266   definition "f x y = x + y + 1"
   267   definition g where "g x = f x x"
   268 
   269   abbreviation
   270     neq  (infix "=!=" 50) where
   271     "x =!= y == ~ (x === y)"
   272 
   273 These specifications may be also used in a locale context.  Then the
   274 constants being introduced depend on certain fixed parameters, and the
   275 constant name is qualified by the locale base name.  An internal
   276 abbreviation takes care for convenient input and output, making the
   277 parameters implicit and using the original short name.  See also
   278 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   279 entities from a monomorphic theory.
   280 
   281 Presently, abbreviations are only available 'in' a target locale, but
   282 not inherited by general import expressions.  Also note that
   283 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   284 'translations' in common applications.
   285 
   286 Concrete syntax is attached to specified constants in internal form,
   287 independently of name spaces.  The parse tree representation is
   288 slightly different -- use 'notation' instead of raw 'syntax', and
   289 'translations' with explicit "CONST" markup to accommodate this.
   290 
   291 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   292 the current context.  Print mode "no_abbrevs" prevents inversion of
   293 abbreviations on output.
   294 
   295 * Isar/locales: improved parameter handling:
   296 - use of locales "var" and "struct" no longer necessary;
   297 - parameter renamings are no longer required to be injective.
   298   This enables, for example, to define a locale for endomorphisms thus:
   299   locale endom = homom mult mult h.
   300 
   301 * Isar/locales: changed the way locales with predicates are defined.
   302 Instead of accumulating the specification, the imported expression is
   303 now an interpretation.  INCOMPATIBILITY: different normal form of
   304 locale expressions.  In particular, in interpretations of locales with
   305 predicates, goals repesenting already interpreted fragments are not
   306 removed automatically.  Use methods `intro_locales' and
   307 `unfold_locales'; see below.
   308 
   309 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   310 provide backward reasoning on locales predicates.  The methods are
   311 aware of interpretations and discharge corresponding goals.
   312 `intro_locales' is less aggressive then `unfold_locales' and does not
   313 unfold predicates to assumptions.
   314 
   315 * Isar/locales: the order in which locale fragments are accumulated
   316 has changed.  This enables to override declarations from fragments due
   317 to interpretations -- for example, unwanted simp rules.
   318 
   319 * Provers/induct: improved internal context management to support
   320 local fixes and defines on-the-fly.  Thus explicit meta-level
   321 connectives !! and ==> are rarely required anymore in inductive goals
   322 (using object-logic connectives for this purpose has been long
   323 obsolete anyway).  The subsequent proof patterns illustrate advanced
   324 techniques of natural induction; general datatypes and inductive sets
   325 work analogously (see also src/HOL/Lambda for realistic examples).
   326 
   327 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   328 parameters:
   329 
   330   lemma
   331     fixes n :: nat and x :: 'a
   332     assumes a: "A n x"
   333     shows "P n x"
   334     using a                     -- {* make induct insert fact a *}
   335   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   336     case 0
   337     show ?case sorry
   338   next
   339     case (Suc n)
   340     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   341     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   342     show ?case sorry
   343   qed
   344 
   345 (2) This is how to perform induction over ``expressions of a certain
   346 form'', using a locally defined inductive parameter n == "a x"
   347 together with strengthening (the latter is usually required to get
   348 sufficiently flexible induction hypotheses):
   349 
   350   lemma
   351     fixes a :: "'a => nat"
   352     assumes a: "A (a x)"
   353     shows "P (a x)"
   354     using a
   355   proof (induct n == "a x" arbitrary: x)
   356     ...
   357 
   358 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   359 particular technique.
   360 
   361 (3) This is how to perform existential reasoning ('obtains' or
   362 'obtain') by induction, while avoiding explicit object-logic
   363 encodings:
   364 
   365   lemma
   366     fixes n :: nat
   367     obtains x :: 'a where "P n x" and "Q n x"
   368   proof (induct n arbitrary: thesis)
   369     case 0
   370     obtain x where "P 0 x" and "Q 0 x" sorry
   371     then show thesis by (rule 0)
   372   next
   373     case (Suc n)
   374     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   375     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   376     then show thesis by (rule Suc.prems)
   377   qed
   378 
   379 Here the 'arbitrary: thesis' specification essentially modifies the
   380 scope of the formal thesis parameter, in order to the get the whole
   381 existence statement through the induction as expected.
   382 
   383 * Provers/induct: mutual induction rules are now specified as a list
   384 of rule sharing the same induction cases.  HOL packages usually
   385 provide foo_bar.inducts for mutually defined items foo and bar
   386 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   387 specify mutual induction rules differently, i.e. like this:
   388 
   389   (induct rule: foo_bar.inducts)
   390   (induct set: foo bar)
   391   (induct type: foo bar)
   392 
   393 The ML function ProjectRule.projections turns old-style rules into the
   394 new format.
   395 
   396 * Provers/induct: improved handling of simultaneous goals.  Instead of
   397 introducing object-level conjunction, the statement is now split into
   398 several conclusions, while the corresponding symbolic cases are
   399 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   400 explicitly.  For example:
   401 
   402   lemma
   403     fixes n :: nat
   404     shows "P n" and "Q n"
   405   proof (induct n)
   406     case 0 case 1
   407     show "P 0" sorry
   408   next
   409     case 0 case 2
   410     show "Q 0" sorry
   411   next
   412     case (Suc n) case 1
   413     note `P n` and `Q n`
   414     show "P (Suc n)" sorry
   415   next
   416     case (Suc n) case 2
   417     note `P n` and `Q n`
   418     show "Q (Suc n)" sorry
   419   qed
   420 
   421 The split into subcases may be deferred as follows -- this is
   422 particularly relevant for goal statements with local premises.
   423 
   424   lemma
   425     fixes n :: nat
   426     shows "A n ==> P n" and "B n ==> Q n"
   427   proof (induct n)
   428     case 0
   429     {
   430       case 1
   431       note `A 0`
   432       show "P 0" sorry
   433     next
   434       case 2
   435       note `B 0`
   436       show "Q 0" sorry
   437     }
   438   next
   439     case (Suc n)
   440     note `A n ==> P n` and `B n ==> Q n`
   441     {
   442       case 1
   443       note `A (Suc n)`
   444       show "P (Suc n)" sorry
   445     next
   446       case 2
   447       note `B (Suc n)`
   448       show "Q (Suc n)" sorry
   449     }
   450   qed
   451 
   452 If simultaneous goals are to be used with mutual rules, the statement
   453 needs to be structured carefully as a two-level conjunction, using
   454 lists of propositions separated by 'and':
   455 
   456   lemma
   457     shows "a : A ==> P1 a"
   458           "a : A ==> P2 a"
   459       and "b : B ==> Q1 b"
   460           "b : B ==> Q2 b"
   461           "b : B ==> Q3 b"
   462   proof (induct set: A B)
   463 
   464 * Provers/induct: support coinduction as well.  See
   465 src/HOL/Library/Coinductive_List.thy for various examples.
   466 
   467 * Attribute "symmetric" produces result with standardized schematic
   468 variables (index 0).  Potential INCOMPATIBILITY.
   469 
   470 * Simplifier: by default the simplifier trace only shows top level
   471 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   472 default. Thus there is less danger of being flooded by the trace. The
   473 trace indicates where parts have been suppressed.
   474   
   475 * Provers/classical: removed obsolete classical version of elim_format
   476 attribute; classical elim/dest rules are now treated uniformly when
   477 manipulating the claset.
   478 
   479 * Provers/classical: stricter checks to ensure that supplied intro,
   480 dest and elim rules are well-formed; dest and elim rules must have at
   481 least one premise.
   482 
   483 * Provers/classical: attributes dest/elim/intro take an optional
   484 weight argument for the rule (just as the Pure versions).  Weights are
   485 ignored by automated tools, but determine the search order of single
   486 rule steps.
   487 
   488 * Syntax: input syntax now supports dummy variable binding "%_. b",
   489 where the body does not mention the bound variable.  Note that dummy
   490 patterns implicitly depend on their context of bounds, which makes
   491 "{_. _}" match any set comprehension as expected.  Potential
   492 INCOMPATIBILITY -- parse translations need to cope with syntactic
   493 constant "_idtdummy" in the binding position.
   494 
   495 * Syntax: removed obsolete syntactic constant "_K" and its associated
   496 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   497 for example "A -> B" => "Pi A (%_. B)".
   498 
   499 * Pure: 'class_deps' command visualizes the subclass relation, using
   500 the graph browser tool.
   501 
   502 * Pure: 'print_theory' now suppresses entities with internal name
   503 (trailing "_") by default; use '!' option for full details.
   504 
   505 
   506 *** HOL ***
   507 
   508 * Addes class (axclass + locale) "preorder" as superclass of "order";
   509 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   510 proofs changed.
   511 
   512 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   513 INCOMPATIBILITY.
   514 
   515 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   516 INCOMPATIBILITY.
   517 
   518 * Added syntactic class "size"; overloaded constant "size" now has
   519 type "'a::size ==> bool"
   520 
   521 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   522 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   523 
   524 * Added method "lexicographic_order" automatically synthesizes
   525 termination relations as lexicographic combinations of size measures
   526 -- 'function' package.
   527 
   528 * HOL/records: generalised field-update to take a function on the
   529 field rather than the new value: r(|A := x|) is translated to A_update
   530 (K x) r The K-combinator that is internally used is called K_record.
   531 INCOMPATIBILITY: Usage of the plain update functions has to be
   532 adapted.
   533  
   534 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   535 0 * x = 0, which are required for a semiring.  Richer structures do
   536 not inherit from semiring_0 anymore, because this property is a
   537 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   538 semiring_0, there is more to prove, but this is mostly trivial.
   539 
   540 * axclass "recpower" was generalized to arbitrary monoids, not just
   541 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   542 commutativity or a semiring property, add the corresponding classes.
   543 
   544 * Unified locale partial_order with class definition (cf. theory
   545 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   546 
   547 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   548 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   549 Isar level, use abbreviations instead.
   550 
   551 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   552 rarely occuring name references (e.g. ``List.op mem.simps'') require
   553 renaming (e.g. ``List.memberl.simps'').
   554 
   555 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   556 INCOMPATIBILITY.
   557 
   558 * Added theory Code_Generator providing class 'eq', allowing for code
   559 generation with polymorphic equality.
   560 
   561 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   562 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   563 significant changes for setting up numeral syntax for types:
   564 
   565   - new constants Numeral.pred and Numeral.succ instead
   566       of former Numeral.bin_pred and Numeral.bin_succ.
   567   - Use integer operations instead of bin_add, bin_mult and so on.
   568   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   569   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   570 
   571 See HOL/Integ/IntArith.thy for an example setup.
   572 
   573 * New top level command 'normal_form' computes the normal form of a
   574 term that may contain free variables. For example ``normal_form
   575 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   576 suitable for heavy-duty computations because the functions are
   577 compiled to ML first.
   578 
   579 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   580 25 like -->); output depends on the "iff" print_mode, the default is
   581 "A = B" (with priority 50).
   582 
   583 * Renamed constants in HOL.thy and Orderings.thy:
   584     op +   ~> HOL.plus
   585     op -   ~> HOL.minus
   586     uminus ~> HOL.uminus
   587     op *   ~> HOL.times
   588     op <   ~> Orderings.less
   589     op <=  ~> Orderings.less_eq
   590 
   591 Adaptions may be required in the following cases:
   592 
   593 a) User-defined constants using any of the names "plus", "minus", "times",
   594 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   595 may go wrong.
   596 INCOMPATIBILITY: use more specific names.
   597 
   598 b) Variables named "plus", "minus", "times", "less", "less_eq"
   599 INCOMPATIBILITY: use more specific names.
   600 
   601 c) Permutative equations (e.g. "a + b = b + a")
   602 Since the change of names also changes the order of terms, permutative
   603 rewrite rules may get applied in a different order. Experience shows that
   604 this is rarely the case (only two adaptions in the whole Isabelle
   605 distribution).
   606 INCOMPATIBILITY: rewrite proofs
   607 
   608 d) ML code directly refering to constant names
   609 This in general only affects hand-written proof tactics, simprocs and so on.
   610 INCOMPATIBILITY: grep your sourcecode and replace names.
   611 
   612 * Relations less (<) and less_eq (<=) are also available on type bool.
   613 Modified syntax to disallow nesting without explicit parentheses,
   614 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   615 
   616 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   617 
   618 * Relation composition operator "op O" now has precedence 75 and binds
   619 stronger than union and intersection. INCOMPATIBILITY.
   620 
   621 * The old set interval syntax "{m..n(}" (and relatives) has been
   622 removed.  Use "{m..<n}" (and relatives) instead.
   623 
   624 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   625 "t = s" to False (by simproc "neq_simproc").  For backward
   626 compatibility this can be disabled by ML "reset use_neq_simproc".
   627 
   628 * "m dvd n" where m and n are numbers is evaluated to True/False by
   629 simp.
   630 
   631 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   632 
   633 * Theorem setsum_mult renamed to setsum_right_distrib.
   634 
   635 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   636 ``rule'' method.
   637 
   638 * Reimplemented methods ``sat'' and ``satx'', with several
   639 improvements: goals no longer need to be stated as "<prems> ==>
   640 False", equivalences (i.e. "=" on type bool) are handled, variable
   641 names of the form "lit_<n>" are no longer reserved, significant
   642 speedup.
   643 
   644 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   645 zChaff is still supported as well.
   646 
   647 * 'inductive' and 'datatype': provide projections of mutual rules,
   648 bundled as foo_bar.inducts;
   649 
   650 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   651 Library.
   652 
   653 * Library: moved theory Accessible_Part to main HOL.
   654 
   655 * Library: added theory Coinductive_List of potentially infinite lists
   656 as greatest fixed-point.
   657 
   658 * Library: added theory AssocList which implements (finite) maps as
   659 association lists.
   660 
   661 * Added proof method ``evaluation'' for efficiently solving a goal
   662 (i.e. a boolean expression) by compiling it to ML. The goal is
   663 "proved" (via an oracle) if it evaluates to True.
   664 
   665 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   666 also when invoked by the simplifier.  This results in the simplifier
   667 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   668 fast_arith_split_limit to 0 to obtain the old behavior.
   669 
   670 * Support for hex (0x20) and binary (0b1001) numerals.
   671 
   672 * New method: reify eqs (t), where eqs are equations for an
   673 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   674 parameter, computes a term s::'b and a list xs::'a list and proves the
   675 theorem I xs s = t. This is also known as reification or quoting. The
   676 resulting theorem is applied to the subgoal to substitute t with I xs
   677 s.  If t is omitted, the subgoal itself is reified.
   678 
   679 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   680 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   681 where f is supposed to be a computable function (in the sense of code
   682 generattion). The method uses reify to compute s and xs as above then
   683 applies corr_thm and uses normalization by evaluation to "prove" f s =
   684 r and finally gets the theorem t = r, which is again applied to the
   685 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   686 
   687 * Reflection: Automatic refification now handels binding, an example
   688 is available in HOL/ex/ReflectionEx.thy
   689 
   690 
   691 *** HOL-Algebra ***
   692 
   693 * Formalisation of ideals and the quotient construction over rings.
   694 
   695 * Order and lattice theory no longer based on records.
   696 INCOMPATIBILITY.
   697 
   698 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   699 greatest_closed.  INCOMPATIBILITY.
   700 
   701 * Method algebra is now set up via an attribute.  For examples see
   702 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   703 of algebraic structures.
   704 
   705 * Renamed theory CRing to Ring.
   706 
   707 
   708 *** HOL-Complex ***
   709 
   710 * Theory Real: new method ferrack implements quantifier elimination
   711 for linear arithmetic over the reals. The quantifier elimination
   712 feature is used only for decision, for compatibility with arith. This
   713 means a goal is either solved or left unchanged, no simplification.
   714 
   715 * Real: New axiomatic classes formalize real normed vector spaces and
   716 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   717 and norm :: 'a => real.
   718 
   719 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   720 from reals into other types. The overloaded constant Reals :: 'a set
   721 is now defined as range of_real; potential INCOMPATIBILITY.
   722 
   723 * Hyperreal: Several constants that previously worked only for the
   724 reals have been generalized, so they now work over arbitrary vector
   725 spaces. Type annotations may need to be added in some cases; potential
   726 INCOMPATIBILITY.
   727 
   728   Infinitesimal  :: ('a::real_normed_vector) star set"
   729   HFinite        :: ('a::real_normed_vector) star set"
   730   HInfinite      :: ('a::real_normed_vector) star set"
   731   approx         :: ('a::real_normed_vector) star => 'a star => bool
   732   monad          :: ('a::real_normed_vector) star => 'a star set
   733   galaxy         :: ('a::real_normed_vector) star => 'a star set
   734   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   735   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   736   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   737   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   738   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   739   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   740   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   741 
   742 * Complex: Some complex-specific constants are now abbreviations for
   743 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   744 hnorm.  Other constants have been entirely removed in favor of the
   745 polymorphic versions (INCOMPATIBILITY):
   746 
   747   approx        <-- capprox
   748   HFinite       <-- CFinite
   749   HInfinite     <-- CInfinite
   750   Infinitesimal <-- CInfinitesimal
   751   monad         <-- cmonad
   752   galaxy        <-- cgalaxy
   753   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   754   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   755   (ns)deriv     <-- (ns)cderiv
   756 
   757 
   758 *** ML ***
   759 
   760 * ML within Isar: antiquotations allow to embed statically-checked
   761 formal entities in the source, referring to the context available at
   762 compile-time.  For example:
   763 
   764 ML {* @{typ "'a => 'b"} *}
   765 ML {* @{term "%x. x"} *}
   766 ML {* @{prop "x == y"} *}
   767 ML {* @{ctyp "'a => 'b"} *}
   768 ML {* @{cterm "%x. x"} *}
   769 ML {* @{cprop "x == y"} *}
   770 ML {* @{thm asm_rl} *}
   771 ML {* @{thms asm_rl} *}
   772 ML {* @{context} *}
   773 ML {* @{theory} *}
   774 ML {* @{theory Pure} *}
   775 ML {* @{simpset} *}
   776 ML {* @{claset} *}
   777 ML {* @{clasimpset} *}
   778 
   779 The same works for sources being ``used'' within an Isar context.
   780 
   781 * ML in Isar: improved error reporting; extra verbosity with
   782 Toplevel.debug enabled.
   783 
   784 * Pure/library:
   785 
   786   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   787   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   788 
   789 The semantics of "burrow" is: "take a function with *simulatanously*
   790 transforms a list of value, and apply it *simulatanously* to a list of
   791 list of values of the appropriate type". Compare this with "map" which
   792 would *not* apply its argument function simulatanously but in
   793 sequence; "fold_burrow" has an additional context.
   794 
   795 * Pure/library: functions map2 and fold2 with curried syntax for
   796 simultanous mapping and folding:
   797 
   798     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   799     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   800 
   801 * Pure/library: indexed lists - some functions in the Isabelle library
   802 treating lists over 'a as finite mappings from [0...n] to 'a have been
   803 given more convenient names and signatures reminiscent of similar
   804 functions for alists, tables, etc:
   805 
   806   val nth: 'a list -> int -> 'a 
   807   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   808   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   809 
   810 Note that fold_index starts counting at index 0, not 1 like foldln
   811 used to.
   812 
   813 * Pure/library: added general ``divide_and_conquer'' combinator on
   814 lists.
   815 
   816 * Pure/General/table.ML: the join operations now works via exceptions
   817 DUP/SAME instead of type option.  This is simpler in simple cases, and
   818 admits slightly more efficient complex applications.
   819 
   820 * Pure: datatype Context.generic joins theory/Proof.context and
   821 provides some facilities for code that works in either kind of
   822 context, notably GenericDataFun for uniform theory and proof data.
   823 
   824 * Pure: 'advanced' translation functions (parse_translation etc.) now
   825 use Context.generic instead of just theory.
   826 
   827 * Pure: simplified internal attribute type, which is now always
   828 Context.generic * thm -> Context.generic * thm.  Global (theory)
   829 vs. local (Proof.context) attributes have been discontinued, while
   830 minimizing code duplication.  Thm.rule_attribute and
   831 Thm.declaration_attribute build canonical attributes; see also
   832 structure Context for further operations on Context.generic, notably
   833 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   834 declarations and definitions.
   835 
   836 * Pure/kernel: consts certification ignores sort constraints given in
   837 signature declarations.  (This information is not relevant to the
   838 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   839 potential INCOMPATIBILITY.
   840 
   841 * Pure: axiomatic type classes are now purely definitional, with
   842 explicit proofs of class axioms and super class relations performed
   843 internally.  See Pure/axclass.ML for the main internal interfaces --
   844 notably AxClass.define_class supercedes AxClass.add_axclass, and
   845 AxClass.axiomatize_class/classrel/arity supercede
   846 Sign.add_classes/classrel/arities.
   847 
   848 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   849 global/local versions on theory vs. Proof.context have been
   850 discontinued; Attrib.syntax and Method.syntax have been adapted
   851 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   852 attributes, methods, etc.
   853 
   854 * Pure: several functions of signature "... -> theory -> theory * ..."
   855 have been reoriented to "... -> theory -> ... * theory" in order to
   856 allow natural usage in combination with the ||>, ||>>, |-> and
   857 fold_map combinators.
   858 
   859 * Pure: official theorem names (closed derivations) and additional
   860 comments (tags) are now strictly separate.  Name hints -- which are
   861 maintained as tags -- may be attached any time without affecting the
   862 derivation.
   863 
   864 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   865 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   866 achieve the old behaviour.
   867 
   868 * Pure: the "Goal" constant is now called "prop", supporting a
   869 slightly more general idea of ``protecting'' meta-level rule
   870 statements.
   871 
   872 * Pure: Logic.(un)varify only works in a global context, which is now
   873 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   874 Logic.legacy_(un)varify as temporary workaround.
   875 
   876 * Pure: structure Name provides scalable operations for generating
   877 internal variable names, notably Name.variants etc.  This replaces
   878 some popular functions from term.ML:
   879 
   880   Term.variant		->  Name.variant
   881   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   882   Term.invent_names	->  Name.invent_list
   883 
   884 Note that low-level renaming rarely occurs in new code -- operations
   885 from structure Variable are used instead (see below).
   886 
   887 * Pure: structure Variable provides fundamental operations for proper
   888 treatment of fixed/schematic variables in a context.  For example,
   889 Variable.import introduces fixes for schematics of given facts and
   890 Variable.export reverses the effect (up to renaming) -- this replaces
   891 various freeze_thaw operations.
   892 
   893 * Pure: structure Goal provides simple interfaces for
   894 init/conclude/finish and tactical prove operations (replacing former
   895 Tactic.prove).  Goal.prove is the canonical way to prove results
   896 within a given context; Goal.prove_global is a degraded version for
   897 theory level goals, including a global Drule.standard.  Note that
   898 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   899 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   900 in a locale context).
   901 
   902 * Isar: simplified treatment of user-level errors, using exception
   903 ERROR of string uniformly.  Function error now merely raises ERROR,
   904 without any side effect on output channels.  The Isar toplevel takes
   905 care of proper display of ERROR exceptions.  ML code may use plain
   906 handle/can/try; cat_error may be used to concatenate errors like this:
   907 
   908   ... handle ERROR msg => cat_error msg "..."
   909 
   910 Toplevel ML code (run directly or through the Isar toplevel) may be
   911 embedded into the Isar toplevel with exception display/debug like
   912 this:
   913 
   914   Isar.toplevel (fn () => ...)
   915 
   916 INCOMPATIBILITY, removed special transform_error facilities, removed
   917 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   918 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   919 -- use plain ERROR instead.
   920 
   921 * Isar: theory setup now has type (theory -> theory), instead of a
   922 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   923 
   924 * Isar: installed ML toplevel pretty printer for type Proof.context,
   925 subject to ProofContext.debug/verbose flags.
   926 
   927 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   928 theory before entering a proof state.  Transactions now always see a
   929 quasi-functional intermediate checkpoint, both in interactive and
   930 batch mode.
   931 
   932 * Simplifier: the simpset of a running simplification process now
   933 contains a proof context (cf. Simplifier.the_context), which is the
   934 very context that the initial simpset has been retrieved from (by
   935 simpset_of/local_simpset_of).  Consequently, all plug-in components
   936 (solver, looper etc.) may depend on arbitrary proof data.
   937 
   938 * Simplifier.inherit_context inherits the proof context (plus the
   939 local bounds) of the current simplification process; any simproc
   940 etc. that calls the Simplifier recursively should do this!  Removed
   941 former Simplifier.inherit_bounds, which is already included here --
   942 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   943 specify an explicit context using Simplifier.context/theory_context.
   944 
   945 * Simplifier/Classical Reasoner: more abstract interfaces
   946 change_simpset/claset for modifying the simpset/claset reference of a
   947 theory; raw versions simpset/claset_ref etc. have been discontinued --
   948 INCOMPATIBILITY.
   949 
   950 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   951 "Trueprop" etc.
   952 
   953 
   954 *** System ***
   955 
   956 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   957 locations -- now includes the Isabelle version identifier as well.
   958 This simplifies use of multiple Isabelle installations.
   959 
   960 * isabelle-process: option -S (secure mode) disables some critical
   961 operations, notably runtime compilation and evaluation of ML source
   962 code.
   963 
   964 
   965 New in Isabelle2005 (October 2005)
   966 ----------------------------------
   967 
   968 *** General ***
   969 
   970 * Theory headers: the new header syntax for Isar theories is
   971 
   972   theory <name>
   973   imports <theory1> ... <theoryN>
   974   uses <file1> ... <fileM>
   975   begin
   976 
   977 where the 'uses' part is optional.  The previous syntax
   978 
   979   theory <name> = <theory1> + ... + <theoryN>:
   980 
   981 will disappear in the next release.  Use isatool fixheaders to convert
   982 existing theory files.  Note that there is no change in ancient
   983 non-Isar theories now, but these will disappear soon.
   984 
   985 * Theory loader: parent theories can now also be referred to via
   986 relative and absolute paths.
   987 
   988 * Command 'find_theorems' searches for a list of criteria instead of a
   989 list of constants. Known criteria are: intro, elim, dest, name:string,
   990 simp:term, and any term. Criteria can be preceded by '-' to select
   991 theorems that do not match. Intro, elim, dest select theorems that
   992 match the current goal, name:s selects theorems whose fully qualified
   993 name contain s, and simp:term selects all simplification rules whose
   994 lhs match term.  Any other term is interpreted as pattern and selects
   995 all theorems matching the pattern. Available in ProofGeneral under
   996 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   997 
   998   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   999 
  1000 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1001 matching the current goal as introduction rule and not having "HOL."
  1002 in their name (i.e. not being defined in theory HOL).
  1003 
  1004 * Command 'thms_containing' has been discontinued in favour of
  1005 'find_theorems'; INCOMPATIBILITY.
  1006 
  1007 * Communication with Proof General is now 8bit clean, which means that
  1008 Unicode text in UTF-8 encoding may be used within theory texts (both
  1009 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1010 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1011 
  1012   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1013   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1014 
  1015 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1016 Classical Reasoner.  Typical big applications run around 2 times
  1017 faster.
  1018 
  1019 
  1020 *** Document preparation ***
  1021 
  1022 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1023 of raw sources.  Only those symbols that do not require additional
  1024 LaTeX packages (depending on comments in isabellesym.sty) are
  1025 displayed properly, everything else is left verbatim.  isatool display
  1026 and isatool print are used as front ends (these are subject to the
  1027 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1028 
  1029 * Command tags control specific markup of certain regions of text,
  1030 notably folding and hiding.  Predefined tags include "theory" (for
  1031 theory begin and end), "proof" for proof commands, and "ML" for
  1032 commands involving ML code; the additional tags "visible" and
  1033 "invisible" are unused by default.  Users may give explicit tag
  1034 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1035 interpretation of tags is determined by the LaTeX job during document
  1036 preparation: see option -V of isatool usedir, or options -n and -t of
  1037 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1038 \isadroptag.
  1039 
  1040 Several document versions may be produced at the same time via isatool
  1041 usedir (the generated index.html will link all of them).  Typical
  1042 specifications include ''-V document=theory,proof,ML'' to present
  1043 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1044 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1045 these parts without any formal replacement text.  The Isabelle site
  1046 default settings produce ''document'' and ''outline'' versions as
  1047 specified above.
  1048 
  1049 * Several new antiquotations:
  1050 
  1051   @{term_type term} prints a term with its type annotated;
  1052 
  1053   @{typeof term} prints the type of a term;
  1054 
  1055   @{const const} is the same as @{term const}, but checks that the
  1056   argument is a known logical constant;
  1057 
  1058   @{term_style style term} and @{thm_style style thm} print a term or
  1059   theorem applying a "style" to it
  1060 
  1061   @{ML text}
  1062 
  1063 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1064 definitions, equations, inequations etc., 'concl' printing only the
  1065 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1066 to print the specified premise.  TermStyle.add_style provides an ML
  1067 interface for introducing further styles.  See also the "LaTeX Sugar"
  1068 document practical applications.  The ML antiquotation prints
  1069 type-checked ML expressions verbatim.
  1070 
  1071 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1072 and 'text' support optional locale specification '(in loc)', which
  1073 specifies the default context for interpreting antiquotations.  For
  1074 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1075 
  1076 * Option 'locale=NAME' of antiquotations specifies an alternative
  1077 context interpreting the subsequent argument.  For example: @{thm
  1078 [locale=lattice] inf_assoc}.
  1079 
  1080 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1081 a proof context.
  1082 
  1083 * Proper output of antiquotations for theory commands involving a
  1084 proof context (such as 'locale' or 'theorem (in loc) ...').
  1085 
  1086 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1087 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1088 
  1089 * isatool usedir: new option -C (default true) controls whether option
  1090 -D should include a copy of the original document directory; -C false
  1091 prevents unwanted effects such as copying of administrative CVS data.
  1092 
  1093 
  1094 *** Pure ***
  1095 
  1096 * Considerably improved version of 'constdefs' command.  Now performs
  1097 automatic type-inference of declared constants; additional support for
  1098 local structure declarations (cf. locales and HOL records), see also
  1099 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1100 sequential dependencies of definitions within a single 'constdefs'
  1101 section; moreover, the declared name needs to be an identifier.  If
  1102 all fails, consider to fall back on 'consts' and 'defs' separately.
  1103 
  1104 * Improved indexed syntax and implicit structures.  First of all,
  1105 indexed syntax provides a notational device for subscripted
  1106 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1107 expressions.  Secondly, in a local context with structure
  1108 declarations, number indexes \<^sub>n or the empty index (default
  1109 number 1) refer to a certain fixed variable implicitly; option
  1110 show_structs controls printing of implicit structures.  Typical
  1111 applications of these concepts involve record types and locales.
  1112 
  1113 * New command 'no_syntax' removes grammar declarations (and
  1114 translations) resulting from the given syntax specification, which is
  1115 interpreted in the same manner as for the 'syntax' command.
  1116 
  1117 * 'Advanced' translation functions (parse_translation etc.) may depend
  1118 on the signature of the theory context being presently used for
  1119 parsing/printing, see also isar-ref manual.
  1120 
  1121 * Improved 'oracle' command provides a type-safe interface to turn an
  1122 ML expression of type theory -> T -> term into a primitive rule of
  1123 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1124 is already included here); see also FOL/ex/IffExample.thy;
  1125 INCOMPATIBILITY.
  1126 
  1127 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1128 before); "cI" is no longer bound, use "c.intro" instead.
  1129 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1130 axclasses vs. locales.
  1131 
  1132 * Improved internal renaming of symbolic identifiers -- attach primes
  1133 instead of base 26 numbers.
  1134 
  1135 * New flag show_question_marks controls printing of leading question
  1136 marks in schematic variable names.
  1137 
  1138 * In schematic variable names, *any* symbol following \<^isub> or
  1139 \<^isup> is now treated as part of the base name.  For example, the
  1140 following works without printing of awkward ".0" indexes:
  1141 
  1142   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1143     by simp
  1144 
  1145 * Inner syntax includes (*(*nested*) comments*).
  1146 
  1147 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1148 annotations as "(00...)".
  1149 
  1150 * Clear separation of logical types and nonterminals, where the latter
  1151 may only occur in 'syntax' specifications or type abbreviations.
  1152 Before that distinction was only partially implemented via type class
  1153 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1154 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1155 exotic syntax specifications may require further adaption
  1156 (e.g. Cube/Cube.thy).
  1157 
  1158 * Removed obsolete type class "logic", use the top sort {} instead.
  1159 Note that non-logical types should be declared as 'nonterminals'
  1160 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1161 specifications.
  1162 
  1163 * Attributes 'induct' and 'cases': type or set names may now be
  1164 locally fixed variables as well.
  1165 
  1166 * Simplifier: can now control the depth to which conditional rewriting
  1167 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1168 Limit.
  1169 
  1170 * Simplifier: simplification procedures may now take the current
  1171 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1172 interface), which is very useful for calling the Simplifier
  1173 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1174 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1175 low-level mk_simproc no longer applies Logic.varify internally, to
  1176 allow for use in a context of fixed variables.
  1177 
  1178 * thin_tac now works even if the assumption being deleted contains !!
  1179 or ==>.  More generally, erule now works even if the major premise of
  1180 the elimination rule contains !! or ==>.
  1181 
  1182 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1183 
  1184 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1185 from Pure, which contains all common declarations already.  Both
  1186 theories are defined via plain Isabelle/Isar .thy files.
  1187 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1188 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1189 use isatool fixcpure to adapt your theory and ML sources.
  1190 
  1191 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1192 selections of theorems in named facts via index ranges.
  1193 
  1194 * 'print_theorems': in theory mode, really print the difference
  1195 wrt. the last state (works for interactive theory development only),
  1196 in proof mode print all local facts (cf. 'print_facts');
  1197 
  1198 * 'hide': option '(open)' hides only base names.
  1199 
  1200 * More efficient treatment of intermediate checkpoints in interactive
  1201 theory development.
  1202 
  1203 * Code generator is now invoked via code_module (incremental code
  1204 generation) and code_library (modular code generation, ML structures
  1205 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1206 must be quoted when used as identifiers.
  1207 
  1208 * New 'value' command for reading, evaluating and printing terms using
  1209 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1210 quoted when used as identifier.
  1211 
  1212 
  1213 *** Locales ***
  1214 
  1215 * New commands for the interpretation of locale expressions in
  1216 theories (1), locales (2) and proof contexts (3).  These generate
  1217 proof obligations from the expression specification.  After the
  1218 obligations have been discharged, theorems of the expression are added
  1219 to the theory, target locale or proof context.  The synopsis of the
  1220 commands is a follows:
  1221 
  1222   (1) interpretation expr inst
  1223   (2) interpretation target < expr
  1224   (3) interpret expr inst
  1225 
  1226 Interpretation in theories and proof contexts require a parameter
  1227 instantiation of terms from the current context.  This is applied to
  1228 specifications and theorems of the interpreted expression.
  1229 Interpretation in locales only permits parameter renaming through the
  1230 locale expression.  Interpretation is smart in that interpretations
  1231 that are active already do not occur in proof obligations, neither are
  1232 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1233 inspect active interpretations of a particular locale.  For details,
  1234 see the Isar Reference manual.  Examples can be found in
  1235 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1236 
  1237 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1238 'interpret' instead.
  1239 
  1240 * New context element 'constrains' for adding type constraints to
  1241 parameters.
  1242 
  1243 * Context expressions: renaming of parameters with syntax
  1244 redeclaration.
  1245 
  1246 * Locale declaration: 'includes' disallowed.
  1247 
  1248 * Proper static binding of attribute syntax -- i.e. types / terms /
  1249 facts mentioned as arguments are always those of the locale definition
  1250 context, independently of the context of later invocations.  Moreover,
  1251 locale operations (renaming and type / term instantiation) are applied
  1252 to attribute arguments as expected.
  1253 
  1254 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1255 actual attributes; rare situations may require Attrib.attribute to
  1256 embed those attributes into Attrib.src that lack concrete syntax.
  1257 Attribute implementations need to cooperate properly with the static
  1258 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1259 Attrib.XXX_thm etc. already do the right thing without further
  1260 intervention.  Only unusual applications -- such as "where" or "of"
  1261 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1262 on the context and the facts involved -- may have to assign parsed
  1263 values to argument tokens explicitly.
  1264 
  1265 * Changed parameter management in theorem generation for long goal
  1266 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1267 theorem statement in rare situations.
  1268 
  1269 * Locale inspection command 'print_locale' omits notes elements.  Use
  1270 'print_locale!' to have them included in the output.
  1271 
  1272 
  1273 *** Provers ***
  1274 
  1275 * Provers/hypsubst.ML: improved version of the subst method, for
  1276 single-step rewriting: it now works in bound variable contexts. New is
  1277 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1278 rewrite a different subterm than the original subst method, which is
  1279 still available as 'simplesubst'.
  1280 
  1281 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1282 and quasi orders.
  1283 
  1284 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1285 reflexive-transitive closure of relations.
  1286 
  1287 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1288 limit (previously hard-coded with a value of 20) user-definable.
  1289 
  1290 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1291 is peformed already.  Object-logics merely need to finish their
  1292 initial simpset configuration as before.  INCOMPATIBILITY.
  1293 
  1294 
  1295 *** HOL ***
  1296 
  1297 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1298 
  1299   syntax (epsilon)
  1300     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1301 
  1302 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1303 and x-symbol; use option '-m epsilon' to get it actually printed.
  1304 Moreover, the mathematically important symbolic identifier \<epsilon>
  1305 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1306 
  1307 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1308 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1309 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1310 support corresponding Isar calculations.
  1311 
  1312 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1313 instead of ":".
  1314 
  1315 * theory SetInterval: changed the syntax for open intervals:
  1316 
  1317   Old       New
  1318   {..n(}    {..<n}
  1319   {)n..}    {n<..}
  1320   {m..n(}   {m..<n}
  1321   {)m..n}   {m<..n}
  1322   {)m..n(}  {m<..<n}
  1323 
  1324 The old syntax is still supported but will disappear in the next
  1325 release.  For conversion use the following Emacs search and replace
  1326 patterns (these are not perfect but work quite well):
  1327 
  1328   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1329   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1330 
  1331 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1332 equalities in commutative rings; method 'algebra' provides a generic
  1333 interface.
  1334 
  1335 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1336 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1337 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1338 be a tuple pattern.
  1339 
  1340 Some new syntax forms are available:
  1341 
  1342   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1343   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1344   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1345   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1346 
  1347 The latter form "\<Sum>x < k. e" used to be based on a separate
  1348 function "Summation", which has been discontinued.
  1349 
  1350 * theory Finite_Set: in structured induction proofs, the insert case
  1351 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1352 (insert F x)'.
  1353 
  1354 * The 'refute' command has been extended to support a much larger
  1355 fragment of HOL, including axiomatic type classes, constdefs and
  1356 typedefs, inductive datatypes and recursion.
  1357 
  1358 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1359 Requires zChaff with proof generation to be installed.  See
  1360 HOL/ex/SAT_Examples.thy for examples.
  1361 
  1362 * Datatype induction via method 'induct' now preserves the name of the
  1363 induction variable. For example, when proving P(xs::'a list) by
  1364 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1365 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1366 in unstructured proof scripts.
  1367 
  1368 * Reworked implementation of records.  Improved scalability for
  1369 records with many fields, avoiding performance problems for type
  1370 inference. Records are no longer composed of nested field types, but
  1371 of nested extension types. Therefore the record type only grows linear
  1372 in the number of extensions and not in the number of fields.  The
  1373 top-level (users) view on records is preserved.  Potential
  1374 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1375 old record representation. The type generated for a record is called
  1376 <record_name>_ext_type.
  1377 
  1378 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1379 proofs triggered by a record definition or a simproc (if
  1380 quick_and_dirty is enabled).  Definitions of large records can take
  1381 quite long.
  1382 
  1383 New simproc record_upd_simproc for simplification of multiple record
  1384 updates enabled by default.  Moreover, trivial updates are also
  1385 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1386 occasionally, since simplification is more powerful by default.
  1387 
  1388 * typedef: proper support for polymorphic sets, which contain extra
  1389 type-variables in the term.
  1390 
  1391 * Simplifier: automatically reasons about transitivity chains
  1392 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1393 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1394 old proofs break occasionally as simplification may now solve more
  1395 goals than previously.
  1396 
  1397 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1398 present.  Works for all partial orders (class "order"), in particular
  1399 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1400 just like y <= x.
  1401 
  1402 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1403 bound variable or a constant then the let is unfolded.  Otherwise
  1404 first a is simplified to b, and then f b is simplified to g. If
  1405 possible we abstract b from g arriving at "let x = b in h x",
  1406 otherwise we unfold the let and arrive at g.  The simproc can be
  1407 enabled/disabled by the reference use_let_simproc.  Potential
  1408 INCOMPATIBILITY since simplification is more powerful by default.
  1409 
  1410 * Classical reasoning: the meson method now accepts theorems as arguments.
  1411 
  1412 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1413 jobs to provide advice on the provability of subgoals.
  1414 
  1415 * Theory OrderedGroup and Ring_and_Field: various additions and
  1416 improvements to faciliate calculations involving equalities and
  1417 inequalities.
  1418 
  1419 The following theorems have been eliminated or modified
  1420 (INCOMPATIBILITY):
  1421 
  1422   abs_eq             now named abs_of_nonneg
  1423   abs_of_ge_0        now named abs_of_nonneg
  1424   abs_minus_eq       now named abs_of_nonpos
  1425   imp_abs_id         now named abs_of_nonneg
  1426   imp_abs_neg_id     now named abs_of_nonpos
  1427   mult_pos           now named mult_pos_pos
  1428   mult_pos_le        now named mult_nonneg_nonneg
  1429   mult_pos_neg_le    now named mult_nonneg_nonpos
  1430   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1431   mult_neg           now named mult_neg_neg
  1432   mult_neg_le        now named mult_nonpos_nonpos
  1433 
  1434 * Theory Parity: added rules for simplifying exponents.
  1435 
  1436 * Theory List:
  1437 
  1438 The following theorems have been eliminated or modified
  1439 (INCOMPATIBILITY):
  1440 
  1441   list_all_Nil       now named list_all.simps(1)
  1442   list_all_Cons      now named list_all.simps(2)
  1443   list_all_conv      now named list_all_iff
  1444   set_mem_eq         now named mem_iff
  1445 
  1446 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1447 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1448 
  1449 
  1450 *** HOL-Complex ***
  1451 
  1452 * Theory RealDef: better support for embedding natural numbers and
  1453 integers in the reals.
  1454 
  1455 The following theorems have been eliminated or modified
  1456 (INCOMPATIBILITY):
  1457 
  1458   exp_ge_add_one_self  now requires no hypotheses
  1459   real_of_int_add      reversed direction of equality (use [symmetric])
  1460   real_of_int_minus    reversed direction of equality (use [symmetric])
  1461   real_of_int_diff     reversed direction of equality (use [symmetric])
  1462   real_of_int_mult     reversed direction of equality (use [symmetric])
  1463 
  1464 * Theory RComplete: expanded support for floor and ceiling functions.
  1465 
  1466 * Theory Ln is new, with properties of the natural logarithm
  1467 
  1468 * Hyperreal: There is a new type constructor "star" for making
  1469 nonstandard types.  The old type names are now type synonyms:
  1470 
  1471   hypreal = real star
  1472   hypnat = nat star
  1473   hcomplex = complex star
  1474 
  1475 * Hyperreal: Many groups of similarly-defined constants have been
  1476 replaced by polymorphic versions (INCOMPATIBILITY):
  1477 
  1478   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1479 
  1480   starset      <-- starsetNat, starsetC
  1481   *s*          <-- *sNat*, *sc*
  1482   starset_n    <-- starsetNat_n, starsetC_n
  1483   *sn*         <-- *sNatn*, *scn*
  1484   InternalSets <-- InternalNatSets, InternalCSets
  1485 
  1486   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1487   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1488   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1489   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1490   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1491 
  1492 * Hyperreal: Many type-specific theorems have been removed in favor of
  1493 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1494 
  1495   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1496   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1497   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1498   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1499   right_minus <-- hypreal_add_minus
  1500   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1501   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1502   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1503   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1504   mult_1_right <-- hcomplex_mult_one_right
  1505   mult_zero_left <-- hcomplex_mult_zero_left
  1506   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1507   right_distrib <-- hypnat_add_mult_distrib2
  1508   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1509   right_inverse <-- hypreal_mult_inverse
  1510   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1511   order_refl <-- {hypreal,hypnat}_le_refl
  1512   order_trans <-- {hypreal,hypnat}_le_trans
  1513   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1514   order_less_le <-- {hypreal,hypnat}_less_le
  1515   linorder_linear <-- {hypreal,hypnat}_le_linear
  1516   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1517   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1518   add_nonneg_nonneg <-- hypreal_le_add_order
  1519 
  1520 * Hyperreal: Separate theorems having to do with type-specific
  1521 versions of constants have been merged into theorems that apply to the
  1522 new polymorphic constants (INCOMPATIBILITY):
  1523 
  1524   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1525   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1526   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1527   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1528   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1529   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1530   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1531   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1532   STAR_diff <-- {STAR,STARC}_diff
  1533   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1534     STARC_hcomplex_of_complex}_image_subset
  1535   starset_n_Un <-- starset{Nat,C}_n_Un
  1536   starset_n_Int <-- starset{Nat,C}_n_Int
  1537   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1538   starset_n_diff <-- starset{Nat,C}_n_diff
  1539   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1540   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1541   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1542   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1543   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1544   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1545   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1546   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1547   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1548   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1549   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1550   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1551   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1552   starfun_diff <-- starfun{C,RC,CR}_diff
  1553   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1554   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1555   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1556   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1557   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1558   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1559   starfun_Id <-- starfunC_Id
  1560   starfun_approx <-- starfun{Nat,CR}_approx
  1561   starfun_capprox <-- starfun{C,RC}_capprox
  1562   starfun_abs <-- starfunNat_rabs
  1563   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1564   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1565   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1566   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1567   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1568   starfun_add_approx <-- starfunCR_add_approx
  1569   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1570   starfun_divide <-- starfun{C,CR,RC}_divide
  1571   starfun_n <-- starfun{Nat,C}_n
  1572   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1573   starfun_n_add <-- starfun{Nat,C}_n_add
  1574   starfun_n_add_minus <-- starfunNat_n_add_minus
  1575   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1576   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1577   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1578 
  1579   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1580   star_n_minus <-- {hypreal,hcomplex}_minus
  1581   star_n_diff <-- {hypreal,hcomplex}_diff
  1582   star_n_mult <-- {hypreal,hcomplex}_mult
  1583   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1584   star_n_le <-- {hypreal,hypnat}_le
  1585   star_n_less <-- {hypreal,hypnat}_less
  1586   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1587   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1588   star_n_abs <-- hypreal_hrabs
  1589   star_n_divide <-- hcomplex_divide
  1590 
  1591   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1592   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1593   star_of_diff <-- hypreal_of_real_diff
  1594   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1595   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1596   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1597   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1598   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1599   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1600   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1601   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1602   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1603   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1604   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1605   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1606   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1607   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1608   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1609   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1610   star_of_power <-- hypreal_of_real_power
  1611   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1612 
  1613 * Hyperreal: new method "transfer" that implements the transfer
  1614 principle of nonstandard analysis. With a subgoal that mentions
  1615 nonstandard types like "'a star", the command "apply transfer"
  1616 replaces it with an equivalent one that mentions only standard types.
  1617 To be successful, all free variables must have standard types; non-
  1618 standard variables must have explicit universal quantifiers.
  1619 
  1620 * Hyperreal: A theory of Taylor series.
  1621 
  1622 
  1623 *** HOLCF ***
  1624 
  1625 * Discontinued special version of 'constdefs' (which used to support
  1626 continuous functions) in favor of the general Pure one with full
  1627 type-inference.
  1628 
  1629 * New simplification procedure for solving continuity conditions; it
  1630 is much faster on terms with many nested lambda abstractions (cubic
  1631 instead of exponential time).
  1632 
  1633 * New syntax for domain package: selector names are now optional.
  1634 Parentheses should be omitted unless argument is lazy, for example:
  1635 
  1636   domain 'a stream = cons "'a" (lazy "'a stream")
  1637 
  1638 * New command 'fixrec' for defining recursive functions with pattern
  1639 matching; defining multiple functions with mutual recursion is also
  1640 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1641 sinr, or any data constructor defined by the domain package. The given
  1642 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1643 syntax and examples.
  1644 
  1645 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1646 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1647 but the proof obligation additionally includes an admissibility
  1648 requirement. The packages generate instances of class cpo or pcpo,
  1649 with continuity and strictness theorems for Rep and Abs.
  1650 
  1651 * HOLCF: Many theorems have been renamed according to a more standard naming
  1652 scheme (INCOMPATIBILITY):
  1653 
  1654   foo_inject:  "foo$x = foo$y ==> x = y"
  1655   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1656   foo_less:    "(foo$x << foo$y) = (x << y)"
  1657   foo_strict:  "foo$UU = UU"
  1658   foo_defined: "... ==> foo$x ~= UU"
  1659   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1660 
  1661 
  1662 *** ZF ***
  1663 
  1664 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1665 including the First Isomorphism Theorem (on quotienting by the kernel
  1666 of a homomorphism).
  1667 
  1668 * ZF/Simplifier: install second copy of type solver that actually
  1669 makes use of TC rules declared to Isar proof contexts (or locales);
  1670 the old version is still required for ML proof scripts.
  1671 
  1672 
  1673 *** Cube ***
  1674 
  1675 * Converted to Isar theory format; use locales instead of axiomatic
  1676 theories.
  1677 
  1678 
  1679 *** ML ***
  1680 
  1681 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1682 for ||>, ||>>, |>>,
  1683 
  1684 * Pure/library.ML no longer defines its own option datatype, but uses
  1685 that of the SML basis, which has constructors NONE and SOME instead of
  1686 None and Some, as well as exception Option.Option instead of OPTION.
  1687 The functions the, if_none, is_some, is_none have been adapted
  1688 accordingly, while Option.map replaces apsome.
  1689 
  1690 * Pure/library.ML: the exception LIST has been given up in favour of
  1691 the standard exceptions Empty and Subscript, as well as
  1692 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1693 superceded by the standard hd and tl functions etc.
  1694 
  1695 A number of basic list functions are no longer exported to the ML
  1696 toplevel, as they are variants of predefined functions.  The following
  1697 suggests how one can translate existing code:
  1698 
  1699     rev_append xs ys = List.revAppend (xs, ys)
  1700     nth_elem (i, xs) = List.nth (xs, i)
  1701     last_elem xs = List.last xs
  1702     flat xss = List.concat xss
  1703     seq fs = List.app fs
  1704     partition P xs = List.partition P xs
  1705     mapfilter f xs = List.mapPartial f xs
  1706 
  1707 * Pure/library.ML: several combinators for linear functional
  1708 transformations, notably reverse application and composition:
  1709 
  1710   x |> f                f #> g
  1711   (x, y) |-> f          f #-> g
  1712 
  1713 * Pure/library.ML: introduced/changed precedence of infix operators:
  1714 
  1715   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1716   infix 2 ?;
  1717   infix 3 o oo ooo oooo;
  1718   infix 4 ~~ upto downto;
  1719 
  1720 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1721 infix operators.
  1722 
  1723 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1724 fold_map support linear functional transformations and nesting.  For
  1725 example:
  1726 
  1727   fold f [x1, ..., xN] y =
  1728     y |> f x1 |> ... |> f xN
  1729 
  1730   (fold o fold) f [xs1, ..., xsN] y =
  1731     y |> fold f xs1 |> ... |> fold f xsN
  1732 
  1733   fold f [x1, ..., xN] =
  1734     f x1 #> ... #> f xN
  1735 
  1736   (fold o fold) f [xs1, ..., xsN] =
  1737     fold f xs1 #> ... #> fold f xsN
  1738 
  1739 * Pure/library.ML: the following selectors on type 'a option are
  1740 available:
  1741 
  1742   the:               'a option -> 'a  (*partial*)
  1743   these:             'a option -> 'a  where 'a = 'b list
  1744   the_default: 'a -> 'a option -> 'a
  1745   the_list:          'a option -> 'a list
  1746 
  1747 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1748 basic operations for association lists, following natural argument
  1749 order; moreover the explicit equality predicate passed here avoids
  1750 potentially expensive polymorphic runtime equality checks.
  1751 The old functions may be expressed as follows:
  1752 
  1753   assoc = uncurry (AList.lookup (op =))
  1754   assocs = these oo AList.lookup (op =)
  1755   overwrite = uncurry (AList.update (op =)) o swap
  1756 
  1757 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1758 
  1759   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1760   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1761 
  1762 replacing make_keylist and keyfilter (occassionally used)
  1763 Naive rewrites:
  1764 
  1765   make_keylist = AList.make
  1766   keyfilter = AList.find (op =)
  1767 
  1768 * eq_fst and eq_snd now take explicit equality parameter, thus
  1769   avoiding eqtypes. Naive rewrites:
  1770 
  1771     eq_fst = eq_fst (op =)
  1772     eq_snd = eq_snd (op =)
  1773 
  1774 * Removed deprecated apl and apr (rarely used).
  1775   Naive rewrites:
  1776 
  1777     apl (n, op) =>>= curry op n
  1778     apr (op, m) =>>= fn n => op (n, m)
  1779 
  1780 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1781 provides a reasonably efficient light-weight implementation of sets as
  1782 lists.
  1783 
  1784 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1785 few new operations; existing lookup and update are now curried to
  1786 follow natural argument order (for use with fold etc.);
  1787 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1788 
  1789 * Pure/General: output via the Isabelle channels of
  1790 writeln/warning/error etc. is now passed through Output.output, with a
  1791 hook for arbitrary transformations depending on the print_mode
  1792 (cf. Output.add_mode -- the first active mode that provides a output
  1793 function wins).  Already formatted output may be embedded into further
  1794 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1795 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1796 accommodate easy composition of diagnostic messages etc.  Programmers
  1797 rarely need to care about Output.output or Output.raw at all, with
  1798 some notable exceptions: Output.output is required when bypassing the
  1799 standard channels (writeln etc.), or in token translations to produce
  1800 properly formatted results; Output.raw is required when capturing
  1801 already output material that will eventually be presented to the user
  1802 a second time.  For the default print mode, both Output.output and
  1803 Output.raw have no effect.
  1804 
  1805 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1806 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1807 cumulative results are displayed at the end of a batch session.
  1808 
  1809 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1810 replaced by File.platform_path and File.shell_path (with appropriate
  1811 hooks).  This provides a clean interface for unusual systems where the
  1812 internal and external process view of file names are different.
  1813 
  1814 * Pure: more efficient orders for basic syntactic entities: added
  1815 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1816 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1817 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1818 orders now -- potential INCOMPATIBILITY for code that depends on a
  1819 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1820 Library.sort_strings on result).
  1821 
  1822 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1823 fold_types traverse types/terms from left to right, observing natural
  1824 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1825 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1826 
  1827 * Pure: name spaces have been refined, with significant changes of the
  1828 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1829 to extern(_table).  The plain name entry path is superceded by a
  1830 general 'naming' context, which also includes the 'policy' to produce
  1831 a fully qualified name and external accesses of a fully qualified
  1832 name; NameSpace.extend is superceded by context dependent
  1833 Sign.declare_name.  Several theory and proof context operations modify
  1834 the naming context.  Especially note Theory.restore_naming and
  1835 ProofContext.restore_naming to get back to a sane state; note that
  1836 Theory.add_path is no longer sufficient to recover from
  1837 Theory.absolute_path in particular.
  1838 
  1839 * Pure: new flags short_names (default false) and unique_names
  1840 (default true) for controlling output of qualified names.  If
  1841 short_names is set, names are printed unqualified.  If unique_names is
  1842 reset, the name prefix is reduced to the minimum required to achieve
  1843 the original result when interning again, even if there is an overlap
  1844 with earlier declarations.
  1845 
  1846 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1847 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1848 (useful for printing error messages).  INCOMPATIBILITY.
  1849 
  1850 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1851 Theory.theory are now identified, referring to the universal
  1852 Context.theory (see Pure/context.ML).  Actual signature and theory
  1853 content is managed as theory data.  The old code and interfaces were
  1854 spread over many files and structures; the new arrangement introduces
  1855 considerable INCOMPATIBILITY to gain more clarity:
  1856 
  1857   Context -- theory management operations (name, identity, inclusion,
  1858     parents, ancestors, merge, etc.), plus generic theory data;
  1859 
  1860   Sign -- logical signature and syntax operations (declaring consts,
  1861     types, etc.), plus certify/read for common entities;
  1862 
  1863   Theory -- logical theory operations (stating axioms, definitions,
  1864     oracles), plus a copy of logical signature operations (consts,
  1865     types, etc.); also a few basic management operations (Theory.copy,
  1866     Theory.merge, etc.)
  1867 
  1868 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1869 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1870 for convenience -- they merely return the theory.
  1871 
  1872 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1873 
  1874 * Pure: the Isar proof context type is already defined early in Pure
  1875 as Context.proof (note that ProofContext.context and Proof.context are
  1876 aliases, where the latter is the preferred name).  This enables other
  1877 Isabelle components to refer to that type even before Isar is present.
  1878 
  1879 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1880 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1881 any of these kinds.  For example, Sign.intern typeK is now
  1882 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1883 Theory.hide_types.  Also note that former
  1884 Theory.hide_classes/types/consts are now
  1885 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1886 internalize their arguments!  INCOMPATIBILITY.
  1887 
  1888 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1889 datatype thmref (with constructors Name and NameSelection) instead of
  1890 plain string -- INCOMPATIBILITY;
  1891 
  1892 * Pure: cases produced by proof methods specify options, where NONE
  1893 means to remove case bindings -- INCOMPATIBILITY in
  1894 (RAW_)METHOD_CASES.
  1895 
  1896 * Pure: the following operations retrieve axioms or theorems from a
  1897 theory node or theory hierarchy, respectively:
  1898 
  1899   Theory.axioms_of: theory -> (string * term) list
  1900   Theory.all_axioms_of: theory -> (string * term) list
  1901   PureThy.thms_of: theory -> (string * thm) list
  1902   PureThy.all_thms_of: theory -> (string * thm) list
  1903 
  1904 * Pure: print_tac now outputs the goal through the trace channel.
  1905 
  1906 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1907 Reference Toplevel.debug (default false) controls detailed printing
  1908 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1909 controls execution profiling -- set to 1 for time and 2 for space
  1910 (both increase the runtime).
  1911 
  1912 * Isar session: The initial use of ROOT.ML is now always timed,
  1913 i.e. the log will show the actual process times, in contrast to the
  1914 elapsed wall-clock time that the outer shell wrapper produces.
  1915 
  1916 * Simplifier: improved handling of bound variables (nameless
  1917 representation, avoid allocating new strings).  Simprocs that invoke
  1918 the Simplifier recursively should use Simplifier.inherit_bounds to
  1919 avoid local name clashes.  Failure to do so produces warnings
  1920 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1921 for further details.
  1922 
  1923 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1924 bindings for all theorems stored within a given theory; this may help
  1925 in porting non-Isar theories to Isar ones, while keeping ML proof
  1926 scripts for the time being.
  1927 
  1928 * ML operator HTML.with_charset specifies the charset begin used for
  1929 generated HTML files.  For example:
  1930 
  1931   HTML.with_charset "utf-8" use_thy "Hebrew";
  1932   HTML.with_charset "utf-8" use_thy "Chinese";
  1933 
  1934 
  1935 *** System ***
  1936 
  1937 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1938 isabelle, isatool etc.).
  1939 
  1940 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1941 isatool doc, isatool mkdir, display_drafts etc.).
  1942 
  1943 * isatool usedir: option -f allows specification of the ML file to be
  1944 used by Isabelle; default is ROOT.ML.
  1945 
  1946 * New isatool version outputs the version identifier of the Isabelle
  1947 distribution being used.
  1948 
  1949 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1950 (containing Boolean satisfiability problems) into Isabelle/HOL
  1951 theories.
  1952 
  1953 
  1954 
  1955 New in Isabelle2004 (April 2004)
  1956 --------------------------------
  1957 
  1958 *** General ***
  1959 
  1960 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1961   Replaces linorder.ML.
  1962 
  1963 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1964   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1965   (\<a>...\<z>), are now considered normal letters, and can therefore
  1966   be used anywhere where an ASCII letter (a...zA...Z) has until
  1967   now. COMPATIBILITY: This obviously changes the parsing of some
  1968   terms, especially where a symbol has been used as a binder, say
  1969   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1970   as an identifier.  Fix it by inserting a space around former
  1971   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1972   existing theory and ML files.
  1973 
  1974 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1975 
  1976 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1977   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1978   a normal (but invisible) letter. For multiple letter subscripts repeat
  1979   \<^isub> like this: x\<^isub>1\<^isub>2.
  1980 
  1981 * Pure: There are now sub-/superscripts that can span more than one
  1982   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1983   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1984   superscript. The new control characters are not identifier parts.
  1985 
  1986 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1987   content of "..." to the latex file instead of \isacntrl... . The "..."
  1988   may consist of any printable characters excluding the end bracket >.
  1989 
  1990 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1991   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1992   declare constants "final", which prevents their being given a definition
  1993   later.  It is useful for constants whose behaviour is fixed axiomatically
  1994   rather than definitionally, such as the meta-logic connectives.
  1995 
  1996 * Pure: 'instance' now handles general arities with general sorts
  1997   (i.e. intersections of classes),
  1998 
  1999 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2000   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2001   It can be changed to alter the colors/layout of generated pages.
  2002 
  2003 
  2004 *** Isar ***
  2005 
  2006 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2007   cut_tac, subgoal_tac and thin_tac:
  2008   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2009     locales are no longer forced to write Isar proof scripts.
  2010     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2011     emulations.
  2012   - INCOMPATIBILITY: names of variables to be instantiated may no
  2013     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2014     This is consistent with the instantiation attribute "where".
  2015 
  2016 * Attributes "where" and "of":
  2017   - Now take type variables of instantiated theorem into account when reading
  2018     the instantiation string.  This fixes a bug that caused instantiated
  2019     theorems to have too special types in some circumstances.
  2020   - "where" permits explicit instantiations of type variables.
  2021 
  2022 * Calculation commands "moreover" and "also" no longer interfere with
  2023   current facts ("this"), admitting arbitrary combinations with "then"
  2024   and derived forms.
  2025 
  2026 * Locales:
  2027   - Goal statements involving the context element "includes" no longer
  2028     generate theorems with internal delta predicates (those ending on
  2029     "_axioms") in the premise.
  2030     Resolve particular premise with <locale>.intro to obtain old form.
  2031   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2032     specification and "includes" elements in goal statement.
  2033   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2034     [intro?] and [elim?] (respectively) by default.
  2035   - Experimental command for instantiation of locales in proof contexts:
  2036         instantiate <label>[<attrs>]: <loc>
  2037     Instantiates locale <loc> and adds all its theorems to the current context
  2038     taking into account their attributes.  Label and attrs are optional
  2039     modifiers, like in theorem declarations.  If present, names of
  2040     instantiated theorems are qualified with <label>, and the attributes
  2041     <attrs> are applied after any attributes these theorems might have already.
  2042       If the locale has assumptions, a chained fact of the form
  2043     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2044     are derived.  The command does not support old-style locales declared
  2045     with "locale (open)".
  2046       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2047 
  2048 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2049   (Isar) contexts.
  2050 
  2051 
  2052 *** HOL ***
  2053 
  2054 * Proof import: new image HOL4 contains the imported library from
  2055   the HOL4 system with about 2500 theorems. It is imported by
  2056   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2057   can be used like any other Isabelle image.  See
  2058   HOL/Import/HOL/README for more information.
  2059 
  2060 * Simplifier:
  2061   - Much improved handling of linear and partial orders.
  2062     Reasoners for linear and partial orders are set up for type classes
  2063     "linorder" and "order" respectively, and are added to the default simpset
  2064     as solvers.  This means that the simplifier can build transitivity chains
  2065     to solve goals from the assumptions.
  2066   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2067     of blast or auto after simplification become unnecessary because the goal
  2068     is solved by simplification already.
  2069 
  2070 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2071     all proved in axiomatic type classes for semirings, rings and fields.
  2072 
  2073 * Numerics:
  2074   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2075     now formalized using the Ring_and_Field theory mentioned above.
  2076   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2077     than before, because now they are set up once in a generic manner.
  2078   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2079     Look for the general versions in Ring_and_Field (and Power if they concern
  2080     exponentiation).
  2081 
  2082 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2083 
  2084 * Records:
  2085   - Record types are now by default printed with their type abbreviation
  2086     instead of the list of all field types. This can be configured via
  2087     the reference "print_record_type_abbr".
  2088   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2089     (not enabled by default).
  2090   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2091     EX x. x = sel r to True (not enabled by default).
  2092   - Tactic "record_split_simp_tac" to split and simplify records added.
  2093 
  2094 * 'specification' command added, allowing for definition by
  2095   specification.  There is also an 'ax_specification' command that
  2096   introduces the new constants axiomatically.
  2097 
  2098 * arith(_tac) is now able to generate counterexamples for reals as well.
  2099 
  2100 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2101 
  2102 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2103   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2104 
  2105 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2106   matrix theory to linear programming.
  2107 
  2108 * Unions and Intersections:
  2109   The latex output syntax of UN and INT has been changed
  2110   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2111   i.e. the index formulae has become a subscript.
  2112   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2113 
  2114 * Unions and Intersections over Intervals:
  2115   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2116   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2117   like in normal math, and corresponding versions for < and for intersection.
  2118 
  2119 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2120   lexicographic dictonary ordering has been added as "lexord".
  2121 
  2122 * ML: the legacy theory structures Int and List have been removed. They had
  2123   conflicted with ML Basis Library structures having the same names.
  2124 
  2125 * 'refute' command added to search for (finite) countermodels.  Only works
  2126   for a fragment of HOL.  The installation of an external SAT solver is
  2127   highly recommended.  See "HOL/Refute.thy" for details.
  2128 
  2129 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2130   formulae under an assignment of free variables to random values.
  2131   In contrast to 'refute', it can deal with inductive datatypes,
  2132   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2133   for examples.
  2134 
  2135 
  2136 *** HOLCF ***
  2137 
  2138 * Streams now come with concatenation and are part of the HOLCF image
  2139 
  2140 
  2141 
  2142 New in Isabelle2003 (May 2003)
  2143 ------------------------------
  2144 
  2145 *** General ***
  2146 
  2147 * Provers/simplifier:
  2148 
  2149   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2150     Assumptions are now subject to complete mutual simplification,
  2151     not just from left to right. The simplifier now preserves
  2152     the order of assumptions.
  2153 
  2154     Potential INCOMPATIBILITY:
  2155 
  2156     -- simp sometimes diverges where the old version did
  2157        not, e.g. invoking simp on the goal
  2158 
  2159         [| P (f x); y = x; f x = f y |] ==> Q
  2160 
  2161        now gives rise to the infinite reduction sequence
  2162 
  2163         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2164 
  2165        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2166        kind of problem.
  2167 
  2168     -- Tactics combining classical reasoner and simplification (such as auto)
  2169        are also affected by this change, because many of them rely on
  2170        simp. They may sometimes diverge as well or yield a different numbers
  2171        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2172        in case of problems. Sometimes subsequent calls to the classical
  2173        reasoner will fail because a preceeding call to the simplifier too
  2174        eagerly simplified the goal, e.g. deleted redundant premises.
  2175 
  2176   - The simplifier trace now shows the names of the applied rewrite rules
  2177 
  2178   - You can limit the number of recursive invocations of the simplifier
  2179     during conditional rewriting (where the simplifie tries to solve the
  2180     conditions before applying the rewrite rule):
  2181     ML "simp_depth_limit := n"
  2182     where n is an integer. Thus you can force termination where previously
  2183     the simplifier would diverge.
  2184 
  2185   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2186 
  2187   - No longer aborts on failed congruence proof.  Instead, the
  2188     congruence is ignored.
  2189 
  2190 * Pure: New generic framework for extracting programs from constructive
  2191   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2192   as HOL/Extraction for some case studies.
  2193 
  2194 * Pure: The main goal of the proof state is no longer shown by default, only
  2195 the subgoals. This behaviour is controlled by a new flag.
  2196    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2197 (ML: Proof.show_main_goal).
  2198 
  2199 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2200 rules whose conclusion matches subgoal 1:
  2201       PG menu: Isabelle/Isar -> Show me -> matching rules
  2202 The rules are ordered by how closely they match the subgoal.
  2203 In particular, rules that solve a subgoal outright are displayed first
  2204 (or rather last, the way they are printed).
  2205 (ML: ProofGeneral.print_intros())
  2206 
  2207 * Pure: New flag trace_unify_fail causes unification to print
  2208 diagnostic information (PG: in trace buffer) when it fails. This is
  2209 useful for figuring out why single step proofs like rule, erule or
  2210 assumption failed.
  2211 
  2212 * Pure: Locale specifications now produce predicate definitions
  2213 according to the body of text (covering assumptions modulo local
  2214 definitions); predicate "loc_axioms" covers newly introduced text,
  2215 while "loc" is cumulative wrt. all included locale expressions; the
  2216 latter view is presented only on export into the global theory
  2217 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2218 on the old view without predicates;
  2219 
  2220 * Pure: predefined locales "var" and "struct" are useful for sharing
  2221 parameters (as in CASL, for example); just specify something like
  2222 ``var x + var y + struct M'' as import;
  2223 
  2224 * Pure: improved thms_containing: proper indexing of facts instead of
  2225 raw theorems; check validity of results wrt. current name space;
  2226 include local facts of proof configuration (also covers active
  2227 locales), cover fixed variables in index; may use "_" in term
  2228 specification; an optional limit for the number of printed facts may
  2229 be given (the default is 40);
  2230 
  2231 * Pure: disallow duplicate fact bindings within new-style theory files
  2232 (batch-mode only);
  2233 
  2234 * Provers: improved induct method: assumptions introduced by case
  2235 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2236 the goal statement); "foo" still refers to all facts collectively;
  2237 
  2238 * Provers: the function blast.overloaded has been removed: all constants
  2239 are regarded as potentially overloaded, which improves robustness in exchange
  2240 for slight decrease in efficiency;
  2241 
  2242 * Provers/linorder: New generic prover for transitivity reasoning over
  2243 linear orders.  Note: this prover is not efficient!
  2244 
  2245 * Isar: preview of problems to finish 'show' now produce an error
  2246 rather than just a warning (in interactive mode);
  2247 
  2248 
  2249 *** HOL ***
  2250 
  2251 * arith(_tac)
  2252 
  2253  - Produces a counter example if it cannot prove a goal.
  2254    Note that the counter example may be spurious if the goal is not a formula
  2255    of quantifier-free linear arithmetic.
  2256    In ProofGeneral the counter example appears in the trace buffer.
  2257 
  2258  - Knows about div k and mod k where k is a numeral of type nat or int.
  2259 
  2260  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2261    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2262    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2263 
  2264 * simp's arithmetic capabilities have been enhanced a bit: it now
  2265 takes ~= in premises into account (by performing a case split);
  2266 
  2267 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2268 are distributed over a sum of terms;
  2269 
  2270 * New tactic "trans_tac" and method "trans" instantiate
  2271 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2272 "<=", "<" and "=").
  2273 
  2274 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2275 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2276 
  2277 * 'typedef' command has new option "open" to suppress the set
  2278 definition;
  2279 
  2280 * functions Min and Max on finite sets have been introduced (theory
  2281 Finite_Set);
  2282 
  2283 * attribute [symmetric] now works for relations as well; it turns
  2284 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2285 
  2286 * induct over a !!-quantified statement (say !!x1..xn):
  2287   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2288 
  2289 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2290 %x. None. Warning: empty_def now refers to the previously hidden definition
  2291 of the empty set.
  2292 
  2293 * Algebra: formalization of classical algebra.  Intended as base for
  2294 any algebraic development in Isabelle.  Currently covers group theory
  2295 (up to Sylow's theorem) and ring theory (Universal Property of
  2296 Univariate Polynomials).  Contributions welcome;
  2297 
  2298 * GroupTheory: deleted, since its material has been moved to Algebra;
  2299 
  2300 * Complex: new directory of the complex numbers with numeric constants,
  2301 nonstandard complex numbers, and some complex analysis, standard and
  2302 nonstandard (Jacques Fleuriot);
  2303 
  2304 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2305 
  2306 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2307 Fleuriot);
  2308 
  2309 * Real/HahnBanach: updated and adapted to locales;
  2310 
  2311 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2312 Gray and Kramer);
  2313 
  2314 * UNITY: added the Meier-Sanders theory of progress sets;
  2315 
  2316 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2317 as abstract algorithms, instantiated to the JVM;
  2318 
  2319 * Bali: Java source language formalization. Type system, operational
  2320 semantics, axiomatic semantics. Supported language features:
  2321 classes, interfaces, objects,virtual methods, static methods,
  2322 static/instance fields, arrays, access modifiers, definite
  2323 assignment, exceptions.
  2324 
  2325 
  2326 *** ZF ***
  2327 
  2328 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2329 universe, etc.);
  2330 
  2331 * Main ZF: virtually all theories converted to new-style format;
  2332 
  2333 
  2334 *** ML ***
  2335 
  2336 * Pure: Tactic.prove provides sane interface for internal proofs;
  2337 omits the infamous "standard" operation, so this is more appropriate
  2338 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2339 
  2340 * Pure: improved error reporting of simprocs;
  2341 
  2342 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2343 up simprocs;
  2344 
  2345 
  2346 *** Document preparation ***
  2347 
  2348 * uses \par instead of \\ for line breaks in theory text. This may
  2349 shift some page breaks in large documents. To get the old behaviour
  2350 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2351 
  2352 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2353 other packages
  2354 
  2355 * \<euro> now needs package babel/greek instead of marvosym (which
  2356 broke \Rightarrow)
  2357 
  2358 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2359 textcomp package)
  2360 
  2361 
  2362 
  2363 New in Isabelle2002 (March 2002)
  2364 --------------------------------
  2365 
  2366 *** Document preparation ***
  2367 
  2368 * greatly simplified document preparation setup, including more
  2369 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2370 instructive isatool mkdir; users should basically be able to get
  2371 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2372 users may run a separate document processing stage manually like this:
  2373 "isatool usedir -D output HOL Test && isatool document Test/output";
  2374 
  2375 * theory dependency graph may now be incorporated into documents;
  2376 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2377 with \includegraphics of LaTeX;
  2378 
  2379 * proper spacing of consecutive markup elements, especially text
  2380 blocks after section headings;
  2381 
  2382 * support bold style (for single symbols only), input syntax is like
  2383 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2384 
  2385 * \<bullet> is now output as bold \cdot by default, which looks much
  2386 better in printed text;
  2387 
  2388 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2389 note that these symbols are currently unavailable in Proof General /
  2390 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2391 
  2392 * isatool latex no longer depends on changed TEXINPUTS, instead
  2393 isatool document copies the Isabelle style files to the target
  2394 location;
  2395 
  2396 
  2397 *** Isar ***
  2398 
  2399 * Pure/Provers: improved proof by cases and induction;
  2400   - 'case' command admits impromptu naming of parameters (such as
  2401     "case (Suc n)");
  2402   - 'induct' method divinates rule instantiation from the inductive
  2403     claim; no longer requires excessive ?P bindings for proper
  2404     instantiation of cases;
  2405   - 'induct' method properly enumerates all possibilities of set/type
  2406     rules; as a consequence facts may be also passed through *type*
  2407     rules without further ado;
  2408   - 'induct' method now derives symbolic cases from the *rulified*
  2409     rule (before it used to rulify cases stemming from the internal
  2410     atomized version); this means that the context of a non-atomic
  2411     statement becomes is included in the hypothesis, avoiding the
  2412     slightly cumbersome show "PROP ?case" form;
  2413   - 'induct' may now use elim-style induction rules without chaining
  2414     facts, using ``missing'' premises from the goal state; this allows
  2415     rules stemming from inductive sets to be applied in unstructured
  2416     scripts, while still benefitting from proper handling of non-atomic
  2417     statements; NB: major inductive premises need to be put first, all
  2418     the rest of the goal is passed through the induction;
  2419   - 'induct' proper support for mutual induction involving non-atomic
  2420     rule statements (uses the new concept of simultaneous goals, see
  2421     below);
  2422   - append all possible rule selections, but only use the first
  2423     success (no backtracking);
  2424   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2425   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2426   - added 'print_induct_rules' (covered by help item in recent Proof
  2427     General versions);
  2428   - moved induct/cases attributes to Pure, methods to Provers;
  2429   - generic method setup instantiated for FOL and HOL;
  2430 
  2431 * Pure: support multiple simultaneous goal statements, for example
  2432 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2433 meta-level mechanism, this acts as if several individual goals had
  2434 been stated separately; in particular common proof methods need to be
  2435 repeated in order to cover all claims; note that a single elimination
  2436 step is *not* sufficient to establish the two conjunctions, so this
  2437 fails:
  2438 
  2439   assume "A & B" then have A and B ..   (*".." fails*)
  2440 
  2441 better use "obtain" in situations as above; alternative refer to
  2442 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2443 
  2444 * Pure: proper integration with ``locales''; unlike the original
  2445 version by Florian Kammller, Isar locales package high-level proof
  2446 contexts rather than raw logical ones (e.g. we admit to include
  2447 attributes everywhere); operations on locales include merge and
  2448 rename; support for implicit arguments (``structures''); simultaneous
  2449 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2450 some examples;
  2451 
  2452 * Pure: the following commands have been ``localized'', supporting a
  2453 target locale specification "(in name)": 'lemma', 'theorem',
  2454 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2455 stored both within the locale and at the theory level (exported and
  2456 qualified by the locale name);
  2457 
  2458 * Pure: theory goals may now be specified in ``long'' form, with
  2459 ad-hoc contexts consisting of arbitrary locale elements. for example
  2460 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2461 definitions may be given, too); the result is a meta-level rule with
  2462 the context elements being discharged in the obvious way;
  2463 
  2464 * Pure: new proof command 'using' allows to augment currently used
  2465 facts after a goal statement ('using' is syntactically analogous to
  2466 'apply', but acts on the goal's facts only); this allows chained facts
  2467 to be separated into parts given before and after a claim, as in
  2468 ``from a and b have C using d and e <proof>'';
  2469 
  2470 * Pure: renamed "antecedent" case to "rule_context";
  2471 
  2472 * Pure: new 'judgment' command records explicit information about the
  2473 object-logic embedding (used by several tools internally); no longer
  2474 use hard-wired "Trueprop";
  2475 
  2476 * Pure: added 'corollary' command;
  2477 
  2478 * Pure: fixed 'token_translation' command;
  2479 
  2480 * Pure: removed obsolete 'exported' attribute;
  2481 
  2482 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2483 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2484 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2485 
  2486 * Pure: method 'atomize' presents local goal premises as object-level
  2487 statements (atomic meta-level propositions); setup controlled via
  2488 rewrite rules declarations of 'atomize' attribute; example
  2489 application: 'induct' method with proper rule statements in improper
  2490 proof *scripts*;
  2491 
  2492 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2493 now consider the syntactic context of assumptions, giving a better
  2494 chance to get type-inference of the arguments right (this is
  2495 especially important for locales);
  2496 
  2497 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2498 mode;
  2499 
  2500 * Pure/obtain: the formal conclusion "thesis", being marked as
  2501 ``internal'', may no longer be reference directly in the text;
  2502 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2503 situations;
  2504 
  2505 * Pure: generic 'sym' attribute which declares a rule both as pure
  2506 'elim?' and for the 'symmetric' operation;
  2507 
  2508 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2509 text; the fixed correlation with particular command syntax has been
  2510 discontinued;
  2511 
  2512 * Pure: new method 'rules' is particularly well-suited for proof
  2513 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2514 but often produces more compact proof terms with less detours;
  2515 
  2516 * Pure/Provers/classical: simplified integration with pure rule
  2517 attributes and methods; the classical "intro?/elim?/dest?"
  2518 declarations coincide with the pure ones; the "rule" method no longer
  2519 includes classically swapped intros; "intro" and "elim" methods no
  2520 longer pick rules from the context; also got rid of ML declarations
  2521 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2522 INCOMPATIBILITY;
  2523 
  2524 * Provers/classical: attribute 'swapped' produces classical inversions
  2525 of introduction rules;
  2526 
  2527 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2528 rules instead of full simplifier context; 'iff' attribute handles
  2529 conditional rules;
  2530 
  2531 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2532 
  2533 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2534 "(permissive)" option to recover old behavior;
  2535 
  2536 * HOL: 'inductive' no longer features separate (collective) attributes
  2537 for 'intros' (was found too confusing);
  2538 
  2539 * HOL: properly declared induction rules less_induct and
  2540 wf_induct_rule;
  2541 
  2542 
  2543 *** HOL ***
  2544 
  2545 * HOL: moved over to sane numeral syntax; the new policy is as
  2546 follows:
  2547 
  2548   - 0 and 1 are polymorphic constants, which are defined on any
  2549   numeric type (nat, int, real etc.);
  2550 
  2551   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2552   binary representation internally;
  2553 
  2554   - type nat has special constructor Suc, and generally prefers Suc 0
  2555   over 1::nat and Suc (Suc 0) over 2::nat;
  2556 
  2557 This change may cause significant problems of INCOMPATIBILITY; here
  2558 are some hints on converting existing sources:
  2559 
  2560   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2561   entities, so expressions involving "-" (unary or binary minus) need
  2562   to be spaced properly;
  2563 
  2564   - existing occurrences of "1" may need to be constraint "1::nat" or
  2565   even replaced by Suc 0; similar for old "2";
  2566 
  2567   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2568 
  2569   - remove all special provisions on numerals in proofs;
  2570 
  2571 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2572 representation (depends on bin_arith_simps in the default context);
  2573 
  2574 * HOL: symbolic syntax for x^2 (numeral 2);
  2575 
  2576 * HOL: the class of all HOL types is now called "type" rather than
  2577 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2578 in axclass/classes, instance/arities, and (usually rare) occurrences
  2579 in typings (of consts etc.); internally the class is called
  2580 "HOL.type", ML programs should refer to HOLogic.typeS;
  2581 
  2582 * HOL/record package improvements:
  2583   - new derived operations "fields" to build a partial record section,
  2584     "extend" to promote a fixed record to a record scheme, and
  2585     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2586     declared as simp by default;
  2587   - shared operations ("more", "fields", etc.) now need to be always
  2588     qualified) --- potential INCOMPATIBILITY;
  2589   - removed "make_scheme" operations (use "make" with "extend") --
  2590     INCOMPATIBILITY;
  2591   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2592   - provides cases/induct rules for use with corresponding Isar
  2593     methods (for concrete records, record schemes, concrete more
  2594     parts, and schematic more parts -- in that order);
  2595   - internal definitions directly based on a light-weight abstract
  2596     theory of product types over typedef rather than datatype;
  2597 
  2598 * HOL: generic code generator for generating executable ML code from
  2599 specifications; specific support for HOL constructs such as inductive
  2600 datatypes and sets, as well as recursive functions; can be invoked
  2601 via 'generate_code' theory section;
  2602 
  2603 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2604 
  2605 * HOL: consolidated and renamed several theories.  In particular:
  2606         Ord.thy has been absorbed into HOL.thy
  2607         String.thy has been absorbed into List.thy
  2608 
  2609 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2610 (beware of argument permutation!);
  2611 
  2612 * HOL: linorder_less_split superseded by linorder_cases;
  2613 
  2614 * HOL/List: "nodups" renamed to "distinct";
  2615 
  2616 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2617 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2618   - Ex_def has changed, now need to use some_eq_ex
  2619 
  2620 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2621 in this (rare) case use:
  2622 
  2623   delSWrapper "split_all_tac"
  2624   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2625 
  2626 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2627 MAY FAIL;
  2628 
  2629 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2630 Isabelle's type classes, ^ on functions and relations has too general
  2631 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2632 necessary to attach explicit type constraints;
  2633 
  2634 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2635 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2636 renamed accordingly (eg "compI" -> "rel_compI").
  2637 
  2638 * HOL: syntax translations now work properly with numerals and records
  2639 expressions;
  2640 
  2641 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2642 of "lam" -- INCOMPATIBILITY;
  2643 
  2644 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2645 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2646 renamed "Product_Type.unit";
  2647 
  2648 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2649 
  2650 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2651 the "cases" method);
  2652 
  2653 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2654 Florian Kammller);
  2655 
  2656 * HOL/IMP: updated and converted to new-style theory format; several
  2657 parts turned into readable document, with proper Isar proof texts and
  2658 some explanations (by Gerwin Klein);
  2659 
  2660 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2661 
  2662 * HOL-Hyperreal is now a logic image;
  2663 
  2664 
  2665 *** HOLCF ***
  2666 
  2667 * Isar: consts/constdefs supports mixfix syntax for continuous
  2668 operations;
  2669 
  2670 * Isar: domain package adapted to new-style theory format, e.g. see
  2671 HOLCF/ex/Dnat.thy;
  2672 
  2673 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2674 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2675 lift.induct_tac, always use UU instead of Undef;
  2676 
  2677 * HOLCF/IMP: updated and converted to new-style theory;
  2678 
  2679 
  2680 *** ZF ***
  2681 
  2682 * Isar: proper integration of logic-specific tools and packages,
  2683 including theory commands '(co)inductive', '(co)datatype',
  2684 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2685 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2686 
  2687 * theory Main no longer includes AC; for the Axiom of Choice, base
  2688 your theory on Main_ZFC;
  2689 
  2690 * the integer library now covers quotients and remainders, with many
  2691 laws relating division to addition, multiplication, etc.;
  2692 
  2693 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2694 typeless version of the formalism;
  2695 
  2696 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2697 format;
  2698 
  2699 * ZF/Induct: new directory for examples of inductive definitions,
  2700 including theory Multiset for multiset orderings; converted to
  2701 new-style theory format;
  2702 
  2703 * ZF: many new theorems about lists, ordinals, etc.;
  2704 
  2705 
  2706 *** General ***
  2707 
  2708 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2709 variable proof controls level of detail: 0 = no proofs (only oracle
  2710 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2711 also ref manual for further ML interfaces;
  2712 
  2713 * Pure/axclass: removed obsolete ML interface
  2714 goal_subclass/goal_arity;
  2715 
  2716 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2717 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2718 separate tokens, so expressions involving minus need to be spaced
  2719 properly;
  2720 
  2721 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2722 rather than "infixl" or "infixr";
  2723 
  2724 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2725 sort constraint specifications in type inference; e.g. "x::_::foo"
  2726 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2727 type variable);
  2728 
  2729 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2730 control output of nested => (types); the default behavior is
  2731 "type_brackets";
  2732 
  2733 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2734 tokens into AST constants;
  2735 
  2736 * Pure/syntax: prefer later declarations of translations and print
  2737 translation functions; potential INCOMPATIBILITY: need to reverse
  2738 multiple declarations for same syntax element constant;
  2739 
  2740 * Pure/show_hyps reset by default (in accordance to existing Isar
  2741 practice);
  2742 
  2743 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2744 addSafter;
  2745 
  2746 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2747 as well;
  2748 
  2749 * system: tested support for MacOS X; should be able to get Isabelle +
  2750 Proof General to work in a plain Terminal after installing Poly/ML
  2751 (e.g. from the Isabelle distribution area) and GNU bash alone
  2752 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2753 support requires further installations, e.g. from
  2754 http://fink.sourceforge.net/);
  2755 
  2756 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2757 
  2758 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2759 of 40 MB), cf. ML_OPTIONS;
  2760 
  2761 * system: Proof General keywords specification is now part of the
  2762 Isabelle distribution (see etc/isar-keywords.el);
  2763 
  2764 * system: support for persistent Proof General sessions (refrain from
  2765 outdating all loaded theories on startup); user may create writable
  2766 logic images like this: ``isabelle -q HOL Test'';
  2767 
  2768 * system: smart selection of Isabelle process versus Isabelle
  2769 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2770 run both "isabelle" and "Isabelle" even if file names are badly
  2771 damaged (executable inspects the case of the first letter of its own
  2772 name); added separate "isabelle-process" and "isabelle-interface";
  2773 
  2774 * system: refrain from any attempt at filtering input streams; no
  2775 longer support ``8bit'' encoding of old isabelle font, instead proper
  2776 iso-latin characters may now be used; the related isatools
  2777 "symbolinput" and "nonascii" have disappeared as well;
  2778 
  2779 * system: removed old "xterm" interface (the print modes "xterm" and
  2780 "xterm_color" are still available for direct use in a suitable
  2781 terminal);
  2782 
  2783 
  2784 
  2785 New in Isabelle99-2 (February 2001)
  2786 -----------------------------------
  2787 
  2788 *** Overview of INCOMPATIBILITIES ***
  2789 
  2790 * HOL: please note that theories in the Library and elsewhere often use the
  2791 new-style (Isar) format; to refer to their theorems in an ML script you must
  2792 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2793 
  2794 * HOL: inductive package no longer splits induction rule aggressively,
  2795 but only as far as specified by the introductions given; the old
  2796 format may be recovered via ML function complete_split_rule or attribute
  2797 'split_rule (complete)';
  2798 
  2799 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2800 gfp_Tarski to gfp_unfold;
  2801 
  2802 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2803 
  2804 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2805 relation); infix "^^" has been renamed "``"; infix "``" has been
  2806 renamed "`"; "univalent" has been renamed "single_valued";
  2807 
  2808 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2809 operation;
  2810 
  2811 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2812 
  2813 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2814 
  2815 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2816 consequence, it is no longer monotonic wrt. the local goal context
  2817 (which is now passed through the inductive cases);
  2818 
  2819 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2820 \<gg> to \<ggreater>;
  2821 
  2822 
  2823 *** Document preparation ***
  2824 
  2825 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2826 available: are "it" for near math-mode best-style output, "sl" for
  2827 slanted text style, and "tt" for plain type-writer; if no
  2828 \isabellestyle command is given, output is according to slanted
  2829 type-writer);
  2830 
  2831 * support sub/super scripts (for single symbols only), input syntax is
  2832 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2833 
  2834 * some more standard symbols; see Appendix A of the system manual for
  2835 the complete list of symbols defined in isabellesym.sty;
  2836 
  2837 * improved isabelle style files; more abstract symbol implementation
  2838 (should now use \isamath{...} and \isatext{...} in custom symbol
  2839 definitions);
  2840 
  2841 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2842 state; Note that presentation of goal states does not conform to
  2843 actual human-readable proof documents.  Please do not include goal
  2844 states into document output unless you really know what you are doing!
  2845 
  2846 * proper indentation of antiquoted output with proportional LaTeX
  2847 fonts;
  2848 
  2849 * no_document ML operator temporarily disables LaTeX document
  2850 generation;
  2851 
  2852 * isatool unsymbolize tunes sources for plain ASCII communication;
  2853 
  2854 
  2855 *** Isar ***
  2856 
  2857 * Pure: Isar now suffers initial goal statements to contain unbound
  2858 schematic variables (this does not conform to actual readable proof
  2859 documents, due to unpredictable outcome and non-compositional proof
  2860 checking); users who know what they are doing may use schematic goals
  2861 for Prolog-style synthesis of proven results;
  2862 
  2863 * Pure: assumption method (an implicit finishing) now handles actual
  2864 rules as well;
  2865 
  2866 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2867 initial goal, declare "that" only as Pure intro (only for single
  2868 steps); the "that" rule assumption may now be involved in implicit
  2869 finishing, thus ".." becomes a feasible for trivial obtains;
  2870 
  2871 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2872 instance proofs may be performed by "..";
  2873 
  2874 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2875 statements as well;
  2876 
  2877 * Pure: more robust selection of calculational rules;
  2878 
  2879 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2880 rule (as well as the assumption rule);
  2881 
  2882 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2883 lemmas, using the graph browser tool;
  2884 
  2885 * Pure: predict failure of "show" in interactive mode;
  2886 
  2887 * Pure: 'thms_containing' now takes actual terms as arguments;
  2888 
  2889 * HOL: improved method 'induct' --- now handles non-atomic goals
  2890 (potential INCOMPATIBILITY); tuned error handling;
  2891 
  2892 * HOL: cases and induct rules now provide explicit hints about the
  2893 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2894 any remaining facts are inserted into the goal verbatim;
  2895 
  2896 * HOL: local contexts (aka cases) may now contain term bindings as
  2897 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2898 the result to be shown in each case;
  2899 
  2900 * HOL: added 'recdef_tc' command;
  2901 
  2902 * isatool convert assists in eliminating legacy ML scripts;
  2903 
  2904 
  2905 *** HOL ***
  2906 
  2907 * HOL/Library: a collection of generic theories to be used together
  2908 with main HOL; the theory loader path already includes this directory
  2909 by default; the following existing theories have been moved here:
  2910 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2911 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2912 
  2913 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2914 modelling and verification task performed in Isabelle/HOL +
  2915 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2916 
  2917 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2918 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2919 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2920 'domain', this makes the theory consistent with mathematical
  2921 literature;
  2922 
  2923 * HOL basics: added overloaded operations "inverse" and "divide"
  2924 (infix "/"), syntax for generic "abs" operation, generic summation
  2925 operator \<Sum>;
  2926 
  2927 * HOL/typedef: simplified package, provide more useful rules (see also
  2928 HOL/subset.thy);
  2929 
  2930 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2931 now expressed as a proper nested rule (old-style tactic scripts may
  2932 require atomize_strip_tac to cope with non-atomic premises);
  2933 
  2934 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2935 to "split_conv" (old name still available for compatibility);
  2936 
  2937 * HOL: improved concrete syntax for strings (e.g. allows translation
  2938 rules with string literals);
  2939 
  2940 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2941  and Fleuriot's mechanization of analysis, including the transcendental
  2942  functions for the reals;
  2943 
  2944 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2945 
  2946 
  2947 *** CTT ***
  2948 
  2949 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2950 "lam" is displayed as TWO lambda-symbols
  2951 
  2952 * CTT: theory Main now available, containing everything (that is, Bool
  2953 and Arith);
  2954 
  2955 
  2956 *** General ***
  2957 
  2958 * Pure: the Simplifier has been implemented properly as a derived rule
  2959 outside of the actual kernel (at last!); the overall performance
  2960 penalty in practical applications is about 50%, while reliability of
  2961 the Isabelle inference kernel has been greatly improved;
  2962 
  2963 * print modes "brackets" and "no_brackets" control output of nested =>
  2964 (types) and ==> (props); the default behaviour is "brackets";
  2965 
  2966 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2967 as assumptions as well;
  2968 
  2969 * system: support Poly/ML 4.0;
  2970 
  2971 * system: isatool install handles KDE version 1 or 2;
  2972 
  2973 
  2974 
  2975 New in Isabelle99-1 (October 2000)
  2976 ----------------------------------
  2977 
  2978 *** Overview of INCOMPATIBILITIES ***
  2979 
  2980 * HOL: simplification of natural numbers is much changed; to partly
  2981 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2982 issue the following ML commands:
  2983 
  2984   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2985   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2986 
  2987 * HOL: simplification no longer dives into case-expressions; this is
  2988 controlled by "t.weak_case_cong" for each datatype t;
  2989 
  2990 * HOL: nat_less_induct renamed to less_induct;
  2991 
  2992 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2993 fixsome to patch .thy and .ML sources automatically;
  2994 
  2995   select_equality  -> some_equality
  2996   select_eq_Ex     -> some_eq_ex
  2997   selectI2EX       -> someI2_ex
  2998   selectI2         -> someI2
  2999   selectI          -> someI
  3000   select1_equality -> some1_equality
  3001   Eps_sym_eq       -> some_sym_eq_trivial
  3002   Eps_eq           -> some_eq_trivial
  3003 
  3004 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3005 
  3006 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3007 instead);
  3008 
  3009 * HOL: the recursion equations generated by 'recdef' are now called
  3010 f.simps instead of f.rules;
  3011 
  3012 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3013 
  3014 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3015 sometimes be needed;
  3016 
  3017 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3018 
  3019 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3020 
  3021 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3022 product is now "<*>" instead of "Times"; the lexicographic product is
  3023 now "<*lex*>" instead of "**";
  3024 
  3025 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3026 of main HOL, but was unused); better use HOL's datatype package;
  3027 
  3028 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3029 the old syntax may be recovered as follows:
  3030 
  3031   syntax (symbols)
  3032     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3033       (infixl "\\<oplus>" 100)
  3034 
  3035 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3036 
  3037 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3038 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3039 internally;
  3040 
  3041 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3042 changed from A/r to A//r;
  3043 
  3044 * ZF: new treatment of arithmetic (nat & int) may break some old
  3045 proofs;
  3046 
  3047 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3048 rulify -> rule_format, elimify -> elim_format, ...);
  3049 
  3050 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3051 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3052 should have to change intro!! to intro? only); replaced "delrule" by
  3053 "rule del";
  3054 
  3055 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3056 
  3057 * Provers: strengthened force_tac by using new first_best_tac;
  3058 
  3059 * LaTeX document preparation: several changes of isabelle.sty (see
  3060 lib/texinputs);
  3061 
  3062 
  3063 *** Document preparation ***
  3064 
  3065 * formal comments (text blocks etc.) in new-style theories may now
  3066 contain antiquotations of thm/prop/term/typ/text to be presented
  3067 according to latex print mode; concrete syntax is like this:
  3068 @{term[show_types] "f(x) = a + x"};
  3069 
  3070 * isatool mkdir provides easy setup of Isabelle session directories,
  3071 including proper document sources;
  3072 
  3073 * generated LaTeX sources are now deleted after successful run
  3074 (isatool document -c); may retain a copy somewhere else via -D option
  3075 of isatool usedir;
  3076 
  3077 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3078 style files, achieving self-contained LaTeX sources and simplifying
  3079 LaTeX debugging;
  3080 
  3081 * old-style theories now produce (crude) LaTeX output as well;
  3082 
  3083 * browser info session directories are now self-contained (may be put
  3084 on WWW server seperately); improved graphs of nested sessions; removed
  3085 graph for 'all sessions';
  3086 
  3087 * several improvements in isabelle style files; \isabellestyle{it}
  3088 produces fake math mode output; \isamarkupheader is now \section by
  3089 default; see lib/texinputs/isabelle.sty etc.;
  3090 
  3091 
  3092 *** Isar ***
  3093 
  3094 * Isar/Pure: local results and corresponding term bindings are now
  3095 subject to Hindley-Milner polymorphism (similar to ML); this
  3096 accommodates incremental type-inference very nicely;
  3097 
  3098 * Isar/Pure: new derived language element 'obtain' supports
  3099 generalized existence reasoning;
  3100 
  3101 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3102 support accumulation of results, without applying any rules yet;
  3103 useful to collect intermediate results without explicit name
  3104 references, and for use with transitivity rules with more than 2
  3105 premises;
  3106 
  3107 * Isar/Pure: scalable support for case-analysis type proofs: new
  3108 'case' language element refers to local contexts symbolically, as
  3109 produced by certain proof methods; internally, case names are attached
  3110 to theorems as "tags";
  3111 
  3112 * Isar/Pure: theory command 'hide' removes declarations from
  3113 class/type/const name spaces;
  3114 
  3115 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3116 indicate potential overloading;
  3117 
  3118 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3119 
  3120 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3121 "{a,b,c}" instead of {a,b,c};
  3122 
  3123 * Isar/Pure now provides its own version of intro/elim/dest
  3124 attributes; useful for building new logics, but beware of confusion
  3125 with the version in Provers/classical;
  3126 
  3127 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3128 case name 'antecedent';
  3129 
  3130 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3131 to the current context is now done automatically);
  3132 
  3133 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3134 for definining proof methods in ML;
  3135 
  3136 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3137 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3138 most cases, one should have to change intro!! to intro? only);
  3139 replaced "delrule" by "rule del";
  3140 
  3141 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3142 'symmetric' attribute (the latter supercedes [RS sym]);
  3143 
  3144 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3145 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3146 well (including splits);
  3147 
  3148 * Isar/Provers: Simplifier and Classical methods now support all kind
  3149 of modifiers used in the past, including 'cong', 'iff', etc.
  3150 
  3151 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3152 of Simplifier and Classical reasoner);
  3153 
  3154 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3155 now support named cases; major packages (inductive, datatype, primrec,
  3156 recdef) support case names and properly name parameters;
  3157 
  3158 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3159 monotonicity conditions are extracted to be proven at end of
  3160 calculations;
  3161 
  3162 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3163 method anyway;
  3164 
  3165 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3166 split_if split_if_asm; datatype package provides theorems foo.splits =
  3167 foo.split foo.split_asm for each datatype;
  3168 
  3169 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3170 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3171 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3172 use "(cases (simplified))" method in proper proof texts);
  3173 
  3174 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3175 
  3176 * Isar: names of theorems etc. may be natural numbers as well;
  3177 
  3178 * Isar: 'pr' command: optional arguments for goals_limit and
  3179 ProofContext.prems_limit; no longer prints theory contexts, but only
  3180 proof states;
  3181 
  3182 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3183 additional print modes to be specified; e.g. "pr(latex)" will print
  3184 proof state according to the Isabelle LaTeX style;
  3185 
  3186 * Isar: improved support for emulating tactic scripts, including proof
  3187 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3188 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3189 (for HOL datatypes);
  3190 
  3191 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3192 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3193 'proof method scripts' have to be in depth-first order;
  3194 
  3195 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3196 
  3197 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3198 should instead use individual commands for printing items
  3199 (print_commands, print_methods etc.);
  3200 
  3201 * Isar: added 'nothing' --- the empty list of theorems;
  3202 
  3203 
  3204 *** HOL ***
  3205 
  3206 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3207 corresponding virtual machine and a specification of its bytecode
  3208 verifier and a lightweight bytecode verifier, including proofs of
  3209 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3210 Cornelia Pusch (see also the homepage of project Bali at
  3211 http://isabelle.in.tum.de/Bali/);
  3212 
  3213 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3214 Clemens Ballarin;
  3215 
  3216 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3217 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3218 Rasmussen;
  3219 
  3220 * HOL/Lattice: fundamental concepts of lattice theory and order
  3221 structures, including duals, properties of bounds versus algebraic
  3222 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3223 Theorem for complete lattices etc.; may also serve as a demonstration
  3224 for abstract algebraic reasoning using axiomatic type classes, and
  3225 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3226 
  3227 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3228 von Oheimb;
  3229 
  3230 * HOL/IMPP: extension of IMP with local variables and mutually
  3231 recursive procedures, by David von Oheimb;
  3232 
  3233 * HOL/Lambda: converted into new-style theory and document;
  3234 
  3235 * HOL/ex/Multiquote: example of multiple nested quotations and
  3236 anti-quotations -- basically a generalized version of de-Bruijn
  3237 representation; very useful in avoiding lifting of operations;
  3238 
  3239 * HOL/record: added general record equality rule to simpset; fixed
  3240 select-update simplification procedure to handle extended records as
  3241 well; admit "r" as field name;
  3242 
  3243 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3244 other numeric types and also as the identity of groups, rings, etc.;
  3245 
  3246 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3247 Types nat and int belong to this axclass;
  3248 
  3249 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3250    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3251    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3252   two terms #m*u and #n*u are replaced by #(m+n)*u
  3253     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3254   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3255     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3256 
  3257 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3258 powerful prover for predicate logic but knows nothing of clasets; see
  3259 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3260 
  3261 * HOL: new version of "case_tac" subsumes both boolean case split and
  3262 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3263 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3264 
  3265 * HOL: simplification no longer dives into case-expressions: only the
  3266 selector expression is simplified, but not the remaining arms; to
  3267 enable full simplification of case-expressions for datatype t, you may
  3268 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3269 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3270 
  3271 * HOL/recdef: the recursion equations generated by 'recdef' for
  3272 function 'f' are now called f.simps instead of f.rules; if all
  3273 termination conditions are proved automatically, these simplification
  3274 rules are added to the simpset, as in primrec; rules may be named
  3275 individually as well, resulting in a separate list of theorems for
  3276 each equation;
  3277 
  3278 * HOL/While is a new theory that provides a while-combinator. It
  3279 permits the definition of tail-recursive functions without the
  3280 provision of a termination measure. The latter is necessary once the
  3281 invariant proof rule for while is applied.
  3282 
  3283 * HOL: new (overloaded) notation for the set of elements below/above
  3284 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3285 
  3286 * HOL: theorems impI, allI, ballI bound as "strip";
  3287 
  3288 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3289 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3290 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3291 
  3292 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3293 
  3294 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3295 main HOL, but was unused);
  3296 
  3297 * HOL: fewer consts declared as global (e.g. have to refer to
  3298 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3299 
  3300 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3301 in case of overlap with user translations (e.g. judgements over
  3302 tuples); (note that the underlying logical represenation is still
  3303 bogus);
  3304 
  3305 
  3306 *** ZF ***
  3307 
  3308 * ZF: simplification automatically cancels common terms in arithmetic
  3309 expressions over nat and int;
  3310 
  3311 * ZF: new treatment of nat to minimize type-checking: all operators
  3312 coerce their operands to a natural number using the function natify,
  3313 making the algebraic laws unconditional;
  3314 
  3315 * ZF: as above, for int: operators coerce their operands to an integer
  3316 using the function intify;
  3317 
  3318 * ZF: the integer library now contains many of the usual laws for the
  3319 orderings, including $<=, and monotonicity laws for $+ and $*;
  3320 
  3321 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3322 simplification;
  3323 
  3324 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3325 to the simplifier and classical reasoner simultaneously;
  3326 
  3327 
  3328 *** General ***
  3329 
  3330 * Provers: blast_tac now handles actual object-logic rules as
  3331 assumptions; note that auto_tac uses blast_tac internally as well;
  3332 
  3333 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3334 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3335 
  3336 * Provers: delrules now handles destruct rules as well (no longer need
  3337 explicit make_elim);
  3338 
  3339 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3340   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3341 use instead the strong form,
  3342   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3343 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3344 from destruct-rules;
  3345 
  3346 * Provers: Simplifier.easy_setup provides a fast path to basic
  3347 Simplifier setup for new object-logics;
  3348 
  3349 * Pure: AST translation rules no longer require constant head on LHS;
  3350 
  3351 * Pure: improved name spaces: ambiguous output is qualified; support
  3352 for hiding of names;
  3353 
  3354 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3355 XSYMBOL_HOME; no longer need to do manual configuration in most
  3356 situations;
  3357 
  3358 * system: compression of ML heaps images may now be controlled via -c
  3359 option of isabelle and isatool usedir (currently only observed by
  3360 Poly/ML);
  3361 
  3362 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3363 useful for remote X11);
  3364 
  3365 * system: provide TAGS file for Isabelle sources;
  3366 
  3367 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3368 order;
  3369 
  3370 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3371 timing flag supersedes proof_timing and Toplevel.trace;
  3372 
  3373 * ML: new combinators |>> and |>>> for incremental transformations
  3374 with secondary results (e.g. certain theory extensions):
  3375 
  3376 * ML: PureThy.add_defs gets additional argument to indicate potential
  3377 overloading (usually false);
  3378 
  3379 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3380 results;
  3381 
  3382 
  3383 
  3384 New in Isabelle99 (October 1999)
  3385 --------------------------------
  3386 
  3387 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3388 
  3389 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3390 are no longer simplified.  (This allows the simplifier to unfold recursive
  3391 functional programs.)  To restore the old behaviour, declare
  3392 
  3393     Delcongs [if_weak_cong];
  3394 
  3395 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3396 complement;
  3397 
  3398 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3399 
  3400 * HOL/datatype: mutual_induct_tac no longer exists --
  3401   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3402 
  3403 * HOL/typedef: fixed type inference for representing set; type
  3404 arguments now have to occur explicitly on the rhs as type constraints;
  3405 
  3406 * ZF: The con_defs part of an inductive definition may no longer refer
  3407 to constants declared in the same theory;
  3408 
  3409 * HOL, ZF: the function mk_cases, generated by the inductive
  3410 definition package, has lost an argument.  To simplify its result, it
  3411 uses the default simpset instead of a supplied list of theorems.
  3412 
  3413 * HOL/List: the constructors of type list are now Nil and Cons;
  3414 
  3415 * Simplifier: the type of the infix ML functions
  3416         setSSolver addSSolver setSolver addSolver
  3417 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3418 for packaging solvers. A solver is created via
  3419         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3420 where the string argument is only a comment.
  3421 
  3422 
  3423 *** Proof tools ***
  3424 
  3425 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3426 decision procedure for linear arithmetic. Currently it is used for
  3427 types `nat', `int', and `real' in HOL (see below); it can, should and
  3428 will be instantiated for other types and logics as well.
  3429 
  3430 * The simplifier now accepts rewrite rules with flexible heads, eg
  3431      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3432   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3433   matching.
  3434 
  3435 
  3436 *** General ***
  3437 
  3438 * New Isabelle/Isar subsystem provides an alternative to traditional
  3439 tactical theorem proving; together with the ProofGeneral/isar user
  3440 interface it offers an interactive environment for developing human
  3441 readable proof documents (Isar == Intelligible semi-automated
  3442 reasoning); for further information see isatool doc isar-ref,
  3443 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3444 
  3445 * improved and simplified presentation of theories: better HTML markup
  3446 (including colors), graph views in several sizes; isatool usedir now
  3447 provides a proper interface for user theories (via -P option); actual
  3448 document preparation based on (PDF)LaTeX is available as well (for
  3449 new-style theories only); see isatool doc system for more information;
  3450 
  3451 * native support for Proof General, both for classic Isabelle and
  3452 Isabelle/Isar;
  3453 
  3454 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3455 using the graph browser tool;
  3456 
  3457 * Isabelle manuals now also available as PDF;
  3458 
  3459 * theory loader rewritten from scratch (may not be fully
  3460 bug-compatible); old loadpath variable has been replaced by show_path,
  3461 add_path, del_path, reset_path functions; new operations such as
  3462 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3463 isatool doc ref);
  3464 
  3465 * improved isatool install: option -k creates KDE application icon,
  3466 option -p DIR installs standalone binaries;
  3467 
  3468 * added ML_PLATFORM setting (useful for cross-platform installations);
  3469 more robust handling of platform specific ML images for SML/NJ;
  3470 
  3471 * the settings environment is now statically scoped, i.e. it is never
  3472 created again in sub-processes invoked from isabelle, isatool, or
  3473 Isabelle;
  3474 
  3475 * path element specification '~~' refers to '$ISABELLE_HOME';
  3476 
  3477 * in locales, the "assumes" and "defines" parts may be omitted if
  3478 empty;
  3479 
  3480 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3481 long arrows);
  3482 
  3483 * new print_mode "HTML";
  3484 
  3485 * new flag show_tags controls display of tags of theorems (which are
  3486 basically just comments that may be attached by some tools);
  3487 
  3488 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3489 mode and goal output format:
  3490 
  3491 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3492 244c244
  3493 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3494 ---
  3495 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3496 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3497 181c181
  3498 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3499 ---
  3500 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3501 
  3502 * function bind_thms stores lists of theorems (cf. bind_thm);
  3503 
  3504 * new shorthand tactics ftac, eatac, datac, fatac;
  3505 
  3506 * qed (and friends) now accept "" as result name; in that case the
  3507 theorem is not stored, but proper checks and presentation of the
  3508 result still apply;
  3509 
  3510 * theorem database now also indexes constants "Trueprop", "all",
  3511 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3512 
  3513 
  3514 *** HOL ***
  3515 
  3516 ** HOL arithmetic **
  3517 
  3518 * There are now decision procedures for linear arithmetic over nat and
  3519 int:
  3520 
  3521 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3522 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3523 are treated as atomic; subformulae not involving type `nat' or `int'
  3524 are ignored; quantified subformulae are ignored unless they are
  3525 positive universal or negative existential. The tactic has to be
  3526 invoked by hand and can be a little bit slow. In particular, the
  3527 running time is exponential in the number of occurrences of `min' and
  3528 `max', and `-' on `nat'.
  3529 
  3530 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3531 (negated) (in)equalities among the premises and the conclusion into
  3532 account (i.e. no compound formulae) and does not know about `min' and
  3533 `max', and `-' on `nat'. It is fast and is used automatically by the
  3534 simplifier.
  3535 
  3536 NB: At the moment, these decision procedures do not cope with mixed
  3537 nat/int formulae where the two parts interact, such as `m < n ==>
  3538 int(m) < int(n)'.
  3539 
  3540 * HOL/Numeral provides a generic theory of numerals (encoded
  3541 efficiently as bit strings); setup for types nat/int/real is in place;
  3542 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3543 int, existing theories and proof scripts may require a few additional
  3544 type constraints;
  3545 
  3546 * integer division and remainder can now be performed on constant
  3547 arguments;
  3548 
  3549 * many properties of integer multiplication, division and remainder
  3550 are now available;
  3551 
  3552 * An interface to the Stanford Validity Checker (SVC) is available through the
  3553 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3554 are proved automatically.  SVC must be installed separately, and its results
  3555 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3556 invocation of the underlying oracle).  For SVC see
  3557   http://verify.stanford.edu/SVC
  3558 
  3559 * IsaMakefile: the HOL-Real target now builds an actual image;
  3560 
  3561 
  3562 ** HOL misc **
  3563 
  3564 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3565 (in Isabelle/Isar) -- by Gertrud Bauer;
  3566 
  3567 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3568 analysis for assembly languages with subtypes;
  3569 
  3570 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3571 -- avoids syntactic ambiguities and treats state, transition, and
  3572 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3573 changed syntax and (many) tactics;
  3574 
  3575 * HOL/inductive: Now also handles more general introduction rules such
  3576   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3577   theorems are now maintained within the theory (maintained via the
  3578   "mono" attribute);
  3579 
  3580 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3581   (using function types) such as
  3582 
  3583   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3584 
  3585 * HOL/record: record_simproc (part of the default simpset) takes care
  3586 of selectors applied to updated records; record_split_tac is no longer
  3587 part of the default claset; update_defs may now be removed from the
  3588 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3589 
  3590   claset_ref () := claset() addSWrapper record_split_wrapper;
  3591   Delsimprocs [record_simproc]
  3592 
  3593 * HOL/typedef: fixed type inference for representing set; type
  3594 arguments now have to occur explicitly on the rhs as type constraints;
  3595 
  3596 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3597 names rather than an ML expression;
  3598 
  3599 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3600 supplied later.  Program schemes can be defined, such as
  3601     "While B C s = (if B s then While B C (C s) else s)"
  3602 where the well-founded relation can be chosen after B and C have been given.
  3603 
  3604 * HOL/List: the constructors of type list are now Nil and Cons;
  3605 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3606 course, ML tools referring to List.list.op # etc. have to be adapted;
  3607 
  3608 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3609 disabled by default; run isabelle with option -m HOL to get back to
  3610 the original Gordon/HOL-style output;
  3611 
  3612 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3613 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3614 
  3615 * HOL basic syntax simplified (more orthogonal): all variants of
  3616 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3617 Eps operator is provided as well: "SOME x. P[x]";
  3618 
  3619 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3620 
  3621 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3622 thus available for user theories;
  3623 
  3624 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3625 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3626 time;
  3627 
  3628 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3629 several times and then mp;
  3630 
  3631 
  3632 *** LK ***
  3633 
  3634 * the notation <<...>> is now available as a notation for sequences of
  3635 formulas;
  3636 
  3637 * the simplifier is now installed
  3638 
  3639 * the axiom system has been generalized (thanks to Soren Heilmann)
  3640 
  3641 * the classical reasoner now has a default rule database
  3642 
  3643 
  3644 *** ZF ***
  3645 
  3646 * new primrec section allows primitive recursive functions to be given
  3647 directly (as in HOL) over datatypes and the natural numbers;
  3648 
  3649 * new tactics induct_tac and exhaust_tac for induction (or case
  3650 analysis) over datatypes and the natural numbers;
  3651 
  3652 * the datatype declaration of type T now defines the recursor T_rec;
  3653 
  3654 * simplification automatically does freeness reasoning for datatype
  3655 constructors;
  3656 
  3657 * automatic type-inference, with AddTCs command to insert new
  3658 type-checking rules;
  3659 
  3660 * datatype introduction rules are now added as Safe Introduction rules
  3661 to the claset;
  3662 
  3663 * the syntax "if P then x else y" is now available in addition to
  3664 if(P,x,y);
  3665 
  3666 
  3667 *** Internal programming interfaces ***
  3668 
  3669 * tuned simplifier trace output; new flag debug_simp;
  3670 
  3671 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3672 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3673 
  3674 * AxClass.axclass_tac lost the theory argument;
  3675 
  3676 * tuned current_goals_markers semantics: begin / end goal avoids
  3677 printing empty lines;
  3678 
  3679 * removed prs and prs_fn hook, which was broken because it did not
  3680 include \n in its semantics, forcing writeln to add one
  3681 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3682 string -> unit if you really want to output text without newline;
  3683 
  3684 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3685 plain output, interface builders may have to enable 'isabelle_font'
  3686 mode to get Isabelle font glyphs as before;
  3687 
  3688 * refined token_translation interface; INCOMPATIBILITY: output length
  3689 now of type real instead of int;
  3690 
  3691 * theory loader actions may be traced via new ThyInfo.add_hook
  3692 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3693 your own database of information attached to *whole* theories -- as
  3694 opposed to intra-theory data slots offered via TheoryDataFun;
  3695 
  3696 * proper handling of dangling sort hypotheses (at last!);
  3697 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3698 extra sort hypotheses that can be witnessed from the type signature;
  3699 the force_strip_shyps flag is gone, any remaining shyps are simply
  3700 left in the theorem (with a warning issued by strip_shyps_warning);
  3701 
  3702 
  3703 
  3704 New in Isabelle98-1 (October 1998)
  3705 ----------------------------------
  3706 
  3707 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3708 
  3709 * several changes of automated proof tools;
  3710 
  3711 * HOL: major changes to the inductive and datatype packages, including
  3712 some minor incompatibilities of theory syntax;
  3713 
  3714 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3715 called `inj_on';
  3716 
  3717 * HOL: removed duplicate thms in Arith:
  3718   less_imp_add_less  should be replaced by  trans_less_add1
  3719   le_imp_add_le      should be replaced by  trans_le_add1
  3720 
  3721 * HOL: unary minus is now overloaded (new type constraints may be
  3722 required);
  3723 
  3724 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3725 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3726 now taken as an integer constant.
  3727 
  3728 * Pure: ML function 'theory_of' renamed to 'theory';
  3729 
  3730 
  3731 *** Proof tools ***
  3732 
  3733 * Simplifier:
  3734   1. Asm_full_simp_tac is now more aggressive.
  3735      1. It will sometimes reorient premises if that increases their power to
  3736         simplify.
  3737      2. It does no longer proceed strictly from left to right but may also
  3738         rotate premises to achieve further simplification.
  3739      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3740      old Asm_full_simp_tac in that it does not rotate premises.
  3741   2. The simplifier now knows a little bit about nat-arithmetic.
  3742 
  3743 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3744 allows for selected deletion of wrappers, by introduction of names for
  3745 wrapper functionals.  This implies that addbefore, addSbefore,
  3746 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3747 and that adding two tactics with the same name overwrites the first
  3748 one (emitting a warning).
  3749   type wrapper = (int -> tactic) -> (int -> tactic)
  3750   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3751   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3752   delWrapper, delSWrapper: claset *  string            -> claset
  3753   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3754 
  3755 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3756 semantics; addbefore now affects only the unsafe part of step_tac
  3757 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3758 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3759 by Force_tac;
  3760 
  3761 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3762 compWrapper; added safe wrapper (and access functions for it);
  3763 
  3764 * HOL/split_all_tac is now much faster and fails if there is nothing
  3765 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3766 and the names of the automatically generated variables have changed.
  3767 split_all_tac has moved within claset() from unsafe wrappers to safe
  3768 wrappers, which means that !!-bound variables are split much more
  3769 aggressively, and safe_tac and clarify_tac now split such variables.
  3770 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3771 Note: the same holds for record_split_tac, which does the job of
  3772 split_all_tac for record fields.
  3773 
  3774 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3775 permanently to the default simpset using Addsplits just like
  3776 Addsimps. They can be removed via Delsplits just like
  3777 Delsimps. Lower-case versions are also available.
  3778 
  3779 * HOL/Simplifier: The rule split_if is now part of the default
  3780 simpset. This means that the simplifier will eliminate all occurrences
  3781 of if-then-else in the conclusion of a goal. To prevent this, you can
  3782 either remove split_if completely from the default simpset by
  3783 `Delsplits [split_if]' or remove it in a specific call of the
  3784 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3785 other case splitting rules to/from the default simpset: every datatype
  3786 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3787 t is the name of the datatype).
  3788 
  3789 * Classical reasoner / Simplifier combination: new force_tac (and
  3790 derivatives Force_tac, force) combines rewriting and classical
  3791 reasoning (and whatever other tools) similarly to auto_tac, but is
  3792 aimed to solve the given subgoal completely.
  3793 
  3794 
  3795 *** General ***
  3796 
  3797 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3798 and `goalw': the theory is no longer needed as an explicit argument -
  3799 the current theory context is used; assumptions are no longer returned
  3800 at the ML-level unless one of them starts with ==> or !!; it is
  3801 recommended to convert to these new commands using isatool fixgoal
  3802 (backup your sources first!);
  3803 
  3804 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3805 the current theory context, and 'theory' to lookup stored theories;
  3806 
  3807 * new theory section 'locale' for declaring constants, assumptions and
  3808 definitions that have local scope;
  3809 
  3810 * new theory section 'nonterminals' for purely syntactic types;
  3811 
  3812 * new theory section 'setup' for generic ML setup functions
  3813 (e.g. package initialization);
  3814 
  3815 * the distribution now includes Isabelle icons: see
  3816 lib/logo/isabelle-{small,tiny}.xpm;
  3817 
  3818 * isatool install - install binaries with absolute references to
  3819 ISABELLE_HOME/bin;
  3820 
  3821 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3822 
  3823 * print mode 'emacs' reserved for Isamode;
  3824 
  3825 * support multiple print (ast) translations per constant name;
  3826 
  3827 * theorems involving oracles are now printed with a suffixed [!];
  3828 
  3829 
  3830 *** HOL ***
  3831 
  3832 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3833 
  3834 * HOL/inductive package reorganized and improved: now supports mutual
  3835 definitions such as
  3836 
  3837   inductive EVEN ODD
  3838     intrs
  3839       null "0 : EVEN"
  3840       oddI "n : EVEN ==> Suc n : ODD"
  3841       evenI "n : ODD ==> Suc n : EVEN"
  3842 
  3843 new theorem list "elims" contains an elimination rule for each of the
  3844 recursive sets; inductive definitions now handle disjunctive premises
  3845 correctly (also ZF);
  3846 
  3847 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3848 "mutual_induct" no longer exists - the induction rule is always
  3849 contained in "induct";
  3850 
  3851 
  3852 * HOL/datatype package re-implemented and greatly improved: now
  3853 supports mutually recursive datatypes such as
  3854 
  3855   datatype
  3856     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3857             | SUM ('a aexp) ('a aexp)
  3858             | DIFF ('a aexp) ('a aexp)
  3859             | NUM 'a
  3860   and
  3861     'a bexp = LESS ('a aexp) ('a aexp)
  3862             | AND ('a bexp) ('a bexp)
  3863             | OR ('a bexp) ('a bexp)
  3864 
  3865 as well as indirectly recursive datatypes such as
  3866 
  3867   datatype
  3868     ('a, 'b) term = Var 'a
  3869                   | App 'b ((('a, 'b) term) list)
  3870 
  3871 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3872 induction on mutually / indirectly recursive datatypes.
  3873 
  3874 Primrec equations are now stored in theory and can be accessed via
  3875 <function_name>.simps.
  3876 
  3877 INCOMPATIBILITIES:
  3878 
  3879   - Theories using datatypes must now have theory Datatype as an
  3880     ancestor.
  3881   - The specific <typename>.induct_tac no longer exists - use the
  3882     generic induct_tac instead.
  3883   - natE has been renamed to nat.exhaust - use exhaust_tac
  3884     instead of res_inst_tac ... natE. Note that the variable
  3885     names in nat.exhaust differ from the names in natE, this
  3886     may cause some "fragile" proofs to fail.
  3887   - The theorems split_<typename>_case and split_<typename>_case_asm
  3888     have been renamed to <typename>.split and <typename>.split_asm.
  3889   - Since default sorts of type variables are now handled correctly,
  3890     some datatype definitions may have to be annotated with explicit
  3891     sort constraints.
  3892   - Primrec definitions no longer require function name and type
  3893     of recursive argument.
  3894 
  3895 Consider using isatool fixdatatype to adapt your theories and proof
  3896 scripts to the new package (backup your sources first!).
  3897 
  3898 
  3899 * HOL/record package: considerably improved implementation; now
  3900 includes concrete syntax for record types, terms, updates; theorems
  3901 for surjective pairing and splitting !!-bound record variables; proof
  3902 support is as follows:
  3903 
  3904   1) standard conversions (selectors or updates applied to record
  3905 constructor terms) are part of the standard simpset;
  3906 
  3907   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3908 made part of standard simpset and claset via addIffs;
  3909 
  3910   3) a tactic for record field splitting (record_split_tac) is part of
  3911 the standard claset (addSWrapper);
  3912 
  3913 To get a better idea about these rules you may retrieve them via
  3914 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3915 the name of your record type.
  3916 
  3917 The split tactic 3) conceptually simplifies by the following rule:
  3918 
  3919   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3920 
  3921 Thus any record variable that is bound by meta-all will automatically
  3922 blow up into some record constructor term, consequently the
  3923 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3924 solve record problems automatically.
  3925 
  3926 
  3927 * reorganized the main HOL image: HOL/Integ and String loaded by
  3928 default; theory Main includes everything;
  3929 
  3930 * automatic simplification of integer sums and comparisons, using cancellation;
  3931 
  3932 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3933 
  3934 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3935 
  3936 * many new identities for unions, intersections, set difference, etc.;
  3937 
  3938 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3939 called split_if, split_split, split_sum_case and split_nat_case (to go
  3940 with add/delsplits);
  3941 
  3942 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3943 (?x::unit) = (); this is made part of the default simpset, which COULD
  3944 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3945 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3946 unit_abs_eta_conv is added in order to counter the effect of
  3947 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3948 %u.f();
  3949 
  3950 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3951 makes more sense);
  3952 
  3953 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3954   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3955   disjointness reasoning but breaking a few old proofs.
  3956 
  3957 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3958 to 'converse' from 'inverse' (for compatibility with ZF and some
  3959 literature);
  3960 
  3961 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3962 the well-founded relation;
  3963 
  3964 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3965     Compl A.  The "Compl" syntax remains available as input syntax for this
  3966     release ONLY.
  3967 
  3968 * HOL/Update: new theory of function updates:
  3969     f(a:=b) == %x. if x=a then b else f x
  3970 may also be iterated as in f(a:=b,c:=d,...);
  3971 
  3972 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3973 
  3974 * HOL/List:
  3975   - new function list_update written xs[i:=v] that updates the i-th
  3976     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3977   - new function `upt' written [i..j(] which generates the list
  3978     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3979     bound write [i..j], which is a shorthand for [i..j+1(].
  3980   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3981 
  3982 * HOL/Arith:
  3983   - removed 'pred' (predecessor) function;
  3984   - generalized some theorems about n-1;
  3985   - many new laws about "div" and "mod";
  3986   - new laws about greatest common divisors (see theory ex/Primes);
  3987 
  3988 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3989 instead of "inverse";
  3990 
  3991 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3992   of the multiset ordering;
  3993 
  3994 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3995   (not included by default);
  3996 
  3997 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3998 
  3999 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4000   programs, i.e. different program variables may have different types.
  4001 
  4002 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4003   [previously, this check worked only if the rewrite rule was unconditional]
  4004   Now rew can involve either definitions or equalities (either == or =).
  4005 
  4006 
  4007 *** ZF ***
  4008 
  4009 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4010   only the theorems proved on ZF.ML;
  4011 
  4012 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4013   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4014   disjointness reasoning but breaking a few old proofs.
  4015 
  4016 * ZF/Update: new theory of function updates
  4017     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4018   may also be iterated as in f(a:=b,c:=d,...);
  4019 
  4020 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4021 
  4022 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4023   [previously, this check worked only if the rewrite rule was unconditional]
  4024   Now rew can involve either definitions or equalities (either == or =).
  4025 
  4026 * case_tac provided for compatibility with HOL
  4027     (like the old excluded_middle_tac, but with subgoals swapped)
  4028 
  4029 
  4030 *** Internal programming interfaces ***
  4031 
  4032 * Pure: several new basic modules made available for general use, see
  4033 also src/Pure/README;
  4034 
  4035 * improved the theory data mechanism to support encapsulation (data
  4036 kind name replaced by private Object.kind, acting as authorization
  4037 key); new type-safe user interface via functor TheoryDataFun; generic
  4038 print_data function becomes basically useless;
  4039 
  4040 * removed global_names compatibility flag -- all theory declarations
  4041 are qualified by default;
  4042 
  4043 * module Pure/Syntax now offers quote / antiquote translation
  4044 functions (useful for Hoare logic etc. with implicit dependencies);
  4045 see HOL/ex/Antiquote for an example use;
  4046 
  4047 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4048 cterm -> thm;
  4049 
  4050 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4051 subgoal;
  4052 
  4053 * Display.print_goals function moved to Locale.print_goals;
  4054 
  4055 * standard print function for goals supports current_goals_markers
  4056 variable for marking begin of proof, end of proof, start of goal; the
  4057 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4058 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4059 for example;
  4060 
  4061 
  4062 
  4063 New in Isabelle98 (January 1998)
  4064 --------------------------------
  4065 
  4066 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4067 
  4068 * changed lexical syntax of terms / types: dots made part of long
  4069 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4070 
  4071 * simpset (and claset) reference variable replaced by functions
  4072 simpset / simpset_ref;
  4073 
  4074 * no longer supports theory aliases (via merge) and non-trivial
  4075 implicit merge of thms' signatures;
  4076 
  4077 * most internal names of constants changed due to qualified names;
  4078 
  4079 * changed Pure/Sequence interface (see Pure/seq.ML);
  4080 
  4081 
  4082 *** General Changes ***
  4083 
  4084 * hierachically structured name spaces (for consts, types, axms, thms
  4085 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4086 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4087 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4088 long_names for fully qualified output names; NOTE: ML programs
  4089 (special tactics, packages etc.) referring to internal names may have
  4090 to be adapted to cope with fully qualified names; in case of severe
  4091 backward campatibility problems try setting 'global_names' at compile
  4092 time to have enrything declared within a flat name space; one may also
  4093 fine tune name declarations in theories via the 'global' and 'local'
  4094 section;
  4095 
  4096 * reimplemented the implicit simpset and claset using the new anytype
  4097 data filed in signatures; references simpset:simpset ref etc. are
  4098 replaced by functions simpset:unit->simpset and
  4099 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4100 to patch your ML files accordingly;
  4101 
  4102 * HTML output now includes theory graph data for display with Java
  4103 applet or isatool browser; data generated automatically via isatool
  4104 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4105 
  4106 * defs may now be conditional; improved rewrite_goals_tac to handle
  4107 conditional equations;
  4108 
  4109 * defs now admits additional type arguments, using TYPE('a) syntax;
  4110 
  4111 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4112 creates a new theory node; implicit merge of thms' signatures is
  4113 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4114 transfer:theory->thm->thm in (rare) cases;
  4115 
  4116 * improved handling of draft signatures / theories; draft thms (and
  4117 ctyps, cterms) are automatically promoted to real ones;
  4118 
  4119 * slightly changed interfaces for oracles: admit many per theory, named
  4120 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4121 
  4122 * print_goals: optional output of const types (set show_consts and
  4123 show_types);
  4124 
  4125 * improved output of warnings (###) and errors (***);
  4126 
  4127 * subgoal_tac displays a warning if the new subgoal has type variables;
  4128 
  4129 * removed old README and Makefiles;
  4130 
  4131 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4132 
  4133 * removed obsolete init_pps and init_database;
  4134 
  4135 * deleted the obsolete tactical STATE, which was declared by
  4136     fun STATE tacfun st = tacfun st st;
  4137 
  4138 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4139 (which abbreviates $HOME);
  4140 
  4141 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4142 use isatool fixseq to adapt your ML programs (this works for fully
  4143 qualified references to the Sequence structure only!);
  4144 
  4145 * use_thy no longer requires writable current directory; it always
  4146 reloads .ML *and* .thy file, if either one is out of date;
  4147 
  4148 
  4149 *** Classical Reasoner ***
  4150 
  4151 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4152 tactics that use classical reasoning to simplify a subgoal without
  4153 splitting it into several subgoals;
  4154 
  4155 * Safe_tac: like safe_tac but uses the default claset;
  4156 
  4157 
  4158 *** Simplifier ***
  4159 
  4160 * added simplification meta rules:
  4161     (asm_)(full_)simplify: simpset -> thm -> thm;
  4162 
  4163 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4164 logics (again);
  4165 
  4166 * added prems argument to simplification procedures;
  4167 
  4168 * HOL, FOL, ZF: added infix function `addsplits':
  4169   instead of `<simpset> setloop (split_tac <thms>)'
  4170   you can simply write `<simpset> addsplits <thms>'
  4171 
  4172 
  4173 *** Syntax ***
  4174 
  4175 * TYPE('a) syntax for type reflection terms;
  4176 
  4177 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4178 
  4179 * pretty printer: changed order of mixfix annotation preference (again!);
  4180 
  4181 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4182 
  4183 
  4184 *** HOL ***
  4185 
  4186 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4187   with `addloop' of the simplifier to faciliate case splitting in premises.
  4188 
  4189 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4190 
  4191 * HOL/Auth: new protocol proofs including some for the Internet
  4192   protocol TLS;
  4193 
  4194 * HOL/Map: new theory of `maps' a la VDM;
  4195 
  4196 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4197 cancelling out common nat summands from =, <, <= (in)equalities, or
  4198 differences; simplification procedures nat_cancel_factor for
  4199 cancelling common factor from =, <, <= (in)equalities over natural
  4200 sums; nat_cancel contains both kinds of procedures, it is installed by
  4201 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4202 
  4203 * HOL/simplifier: terms of the form
  4204   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4205   are rewritten to
  4206   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4207   and those of the form
  4208   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4209   are rewritten to
  4210   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4211 
  4212 * HOL/datatype
  4213   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4214 
  4215   P(t_case f1 ... fn x) =
  4216      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4217         ...
  4218        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4219      )
  4220 
  4221   and a theorem `split_t_case_asm' of the form
  4222 
  4223   P(t_case f1 ... fn x) =
  4224     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4225         ...
  4226        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4227      )
  4228   which can be added to a simpset via `addsplits'. The existing theorems
  4229   expand_list_case and expand_option_case have been renamed to
  4230   split_list_case and split_option_case.
  4231 
  4232 * HOL/Arithmetic:
  4233   - `pred n' is automatically converted to `n-1'.
  4234     Users are strongly encouraged not to use `pred' any longer,
  4235     because it will disappear altogether at some point.
  4236   - Users are strongly encouraged to write "0 < n" rather than
  4237     "n ~= 0". Theorems and proof tools have been modified towards this
  4238     `standard'.
  4239 
  4240 * HOL/Lists:
  4241   the function "set_of_list" has been renamed "set" (and its theorems too);
  4242   the function "nth" now takes its arguments in the reverse order and
  4243   has acquired the infix notation "!" as in "xs!n".
  4244 
  4245 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4246 
  4247 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4248   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4249 
  4250 * HOL/record: extensible records with schematic structural subtyping
  4251 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4252 still lacks various theorems and concrete record syntax;
  4253 
  4254 
  4255 *** HOLCF ***
  4256 
  4257 * removed "axioms" and "generated by" sections;
  4258 
  4259 * replaced "ops" section by extended "consts" section, which is capable of
  4260   handling the continuous function space "->" directly;
  4261 
  4262 * domain package:
  4263   . proves theorems immediately and stores them in the theory,
  4264   . creates hierachical name space,
  4265   . now uses normal mixfix annotations (instead of cinfix...),
  4266   . minor changes to some names and values (for consistency),
  4267   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4268   . separator between mutual domain defs: changed "," to "and",
  4269   . improved handling of sort constraints;  now they have to
  4270     appear on the left-hand side of the equations only;
  4271 
  4272 * fixed LAM <x,y,zs>.b syntax;
  4273 
  4274 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4275 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4276 
  4277 
  4278 *** FOL and ZF ***
  4279 
  4280 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4281   with `addloop' of the simplifier to faciliate case splitting in premises.
  4282 
  4283 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4284 in HOL, they strip ALL and --> from proved theorems;
  4285 
  4286 
  4287 
  4288 New in Isabelle94-8 (May 1997)
  4289 ------------------------------
  4290 
  4291 *** General Changes ***
  4292 
  4293 * new utilities to build / run / maintain Isabelle etc. (in parts
  4294 still somewhat experimental); old Makefiles etc. still functional;
  4295 
  4296 * new 'Isabelle System Manual';
  4297 
  4298 * INSTALL text, together with ./configure and ./build scripts;
  4299 
  4300 * reimplemented type inference for greater efficiency, better error
  4301 messages and clean internal interface;
  4302 
  4303 * prlim command for dealing with lots of subgoals (an easier way of
  4304 setting goals_limit);
  4305 
  4306 
  4307 *** Syntax ***
  4308 
  4309 * supports alternative (named) syntax tables (parser and pretty
  4310 printer); internal interface is provided by add_modesyntax(_i);
  4311 
  4312 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4313 be used in conjunction with the Isabelle symbol font; uses the
  4314 "symbols" syntax table;
  4315 
  4316 * added token_translation interface (may translate name tokens in
  4317 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4318 the current print_mode); IMPORTANT: user print translation functions
  4319 are responsible for marking newly introduced bounds
  4320 (Syntax.mark_boundT);
  4321 
  4322 * token translations for modes "xterm" and "xterm_color" that display
  4323 names in bold, underline etc. or colors (which requires a color
  4324 version of xterm);
  4325 
  4326 * infixes may now be declared with names independent of their syntax;
  4327 
  4328 * added typed_print_translation (like print_translation, but may
  4329 access type of constant);
  4330 
  4331 
  4332 *** Classical Reasoner ***
  4333 
  4334 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4335 some limitations.  Blast_tac...
  4336   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4337   + ignores elimination rules that don't have the correct format
  4338         (the conclusion MUST be a formula variable)
  4339   + ignores types, which can make HOL proofs fail
  4340   + rules must not require higher-order unification, e.g. apply_type in ZF
  4341     [message "Function Var's argument not a bound variable" relates to this]
  4342   + its proof strategy is more general but can actually be slower
  4343 
  4344 * substitution with equality assumptions no longer permutes other
  4345 assumptions;
  4346 
  4347 * minor changes in semantics of addafter (now called addaltern); renamed
  4348 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4349 (and access functions for it);
  4350 
  4351 * improved combination of classical reasoner and simplifier:
  4352   + functions for handling clasimpsets
  4353   + improvement of addss: now the simplifier is called _after_ the
  4354     safe steps.
  4355   + safe variant of addss called addSss: uses safe simplifications
  4356     _during_ the safe steps. It is more complete as it allows multiple
  4357     instantiations of unknowns (e.g. with slow_tac).
  4358 
  4359 *** Simplifier ***
  4360 
  4361 * added interface for simplification procedures (functions that
  4362 produce *proven* rewrite rules on the fly, depending on current
  4363 redex);
  4364 
  4365 * ordering on terms as parameter (used for ordered rewriting);
  4366 
  4367 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4368 
  4369 * the solver is now split into a safe and an unsafe part.
  4370 This should be invisible for the normal user, except that the
  4371 functions setsolver and addsolver have been renamed to setSolver and
  4372 addSolver; added safe_asm_full_simp_tac;
  4373 
  4374 
  4375 *** HOL ***
  4376 
  4377 * a generic induction tactic `induct_tac' which works for all datatypes and
  4378 also for type `nat';
  4379 
  4380 * a generic case distinction tactic `exhaust_tac' which works for all
  4381 datatypes and also for type `nat';
  4382 
  4383 * each datatype comes with a function `size';
  4384 
  4385 * patterns in case expressions allow tuple patterns as arguments to
  4386 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4387 
  4388 * primrec now also works with type nat;
  4389 
  4390 * recdef: a new declaration form, allows general recursive functions to be
  4391 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4392 
  4393 * the constant for negation has been renamed from "not" to "Not" to
  4394 harmonize with FOL, ZF, LK, etc.;
  4395 
  4396 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4397 infinite lists;
  4398 
  4399 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4400 
  4401 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4402 problems in commutative rings, using axiomatic type classes for + and *;
  4403 
  4404 * more examples in HOL/MiniML and HOL/Auth;
  4405 
  4406 * more default rewrite rules for quantifiers, union/intersection;
  4407 
  4408 * a new constant `arbitrary == @x.False';
  4409 
  4410 * HOLCF/IOA replaces old HOL/IOA;
  4411 
  4412 * HOLCF changes: derived all rules and arities
  4413   + axiomatic type classes instead of classes
  4414   + typedef instead of faking type definitions
  4415   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4416   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4417   + eliminated the types void, one, tr
  4418   + use unit lift and bool lift (with translations) instead of one and tr
  4419   + eliminated blift from Lift3.thy (use Def instead of blift)
  4420   all eliminated rules are derived as theorems --> no visible changes ;
  4421 
  4422 
  4423 *** ZF ***
  4424 
  4425 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4426 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4427 as ZF_cs addSIs [equalityI];
  4428 
  4429 
  4430 
  4431 New in Isabelle94-7 (November 96)
  4432 ---------------------------------
  4433 
  4434 * allowing negative levels (as offsets) in prlev and choplev;
  4435 
  4436 * super-linear speedup for large simplifications;
  4437 
  4438 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4439 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4440 FAIL); can suppress it using the command Delsimps (ex_simps @
  4441 all_simps); De Morgan laws are also now included, by default;
  4442 
  4443 * improved printing of ==>  :  ~:
  4444 
  4445 * new object-logic "Sequents" adds linear logic, while replacing LK
  4446 and Modal (thanks to Sara Kalvala);
  4447 
  4448 * HOL/Auth: correctness proofs for authentication protocols;
  4449 
  4450 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4451 examples on HOL/Auth);
  4452 
  4453 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4454 the rewriter and classical reasoner simultaneously;
  4455 
  4456 * function uresult no longer returns theorems in "standard" format;
  4457 regain previous version by: val uresult = standard o uresult;
  4458 
  4459 
  4460 
  4461 New in Isabelle94-6
  4462 -------------------
  4463 
  4464 * oracles -- these establish an interface between Isabelle and trusted
  4465 external reasoners, which may deliver results as theorems;
  4466 
  4467 * proof objects (in particular record all uses of oracles);
  4468 
  4469 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4470 
  4471 * "constdefs" section in theory files;
  4472 
  4473 * "primrec" section (HOL) no longer requires names;
  4474 
  4475 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4476 
  4477 
  4478 
  4479 New in Isabelle94-5
  4480 -------------------
  4481 
  4482 * reduced space requirements;
  4483 
  4484 * automatic HTML generation from theories;
  4485 
  4486 * theory files no longer require "..." (quotes) around most types;
  4487 
  4488 * new examples, including two proofs of the Church-Rosser theorem;
  4489 
  4490 * non-curried (1994) version of HOL is no longer distributed;
  4491 
  4492 
  4493 
  4494 New in Isabelle94-4
  4495 -------------------
  4496 
  4497 * greatly reduced space requirements;
  4498 
  4499 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4500 
  4501 * searchable theorem database (see the section "Retrieving theorems" on
  4502 page 8 of the Reference Manual);
  4503 
  4504 * new examples, including Grabczewski's monumental case study of the
  4505 Axiom of Choice;
  4506 
  4507 * The previous version of HOL renamed to Old_HOL;
  4508 
  4509 * The new version of HOL (previously called CHOL) uses a curried syntax
  4510 for functions.  Application looks like f a b instead of f(a,b);
  4511 
  4512 * Mutually recursive inductive definitions finally work in HOL;
  4513 
  4514 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4515 translates to the operator "split";
  4516 
  4517 
  4518 
  4519 New in Isabelle94-3
  4520 -------------------
  4521 
  4522 * new infix operator, addss, allowing the classical reasoner to
  4523 perform simplification at each step of its search.  Example:
  4524         fast_tac (cs addss ss)
  4525 
  4526 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4527 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4528 look like (a,b) instead of <a,b>;
  4529 
  4530 * PLEASE NOTE: CHOL will eventually replace HOL!
  4531 
  4532 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4533 It translates to the operator "split".  A new theory of integers is available;
  4534 
  4535 * In ZF, integer numerals now denote two's-complement binary integers.
  4536 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4537 
  4538 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4539 of the Axiom of Choice;
  4540 
  4541 
  4542 
  4543 New in Isabelle94-2
  4544 -------------------
  4545 
  4546 * Significantly faster resolution;
  4547 
  4548 * the different sections in a .thy file can now be mixed and repeated
  4549 freely;
  4550 
  4551 * Database of theorems for FOL, HOL and ZF.  New
  4552 commands including qed, qed_goal and bind_thm store theorems in the database.
  4553 
  4554 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4555 a given theory (thms_of), or find out what theory a theorem was proved in
  4556 (theory_of_thm);
  4557 
  4558 * Bugs fixed in the inductive definition and datatype packages;
  4559 
  4560 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4561 and HOL_dup_cs obsolete;
  4562 
  4563 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4564 have been removed;
  4565 
  4566 * Simpler definition of function space in ZF;
  4567 
  4568 * new results about cardinal and ordinal arithmetic in ZF;
  4569 
  4570 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4571 types;
  4572 
  4573 
  4574 $Id$