NEWS
author wenzelm
Sun Dec 10 15:30:31 2006 +0100 (2006-12-10)
changeset 21735 0c65e072f4be
parent 21717 410ca6910f6f
child 21791 367477e8458b
permissions -rw-r--r--
added print_abbrevs;
tuned;
     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 
    46 *** Document preparation ***
    47 
    48 * Added antiquotation @{theory name} which prints the given name,
    49 after checking that it refers to a valid ancestor theory in the
    50 current context.
    51 
    52 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    53 check the given source text as ML type/structure, printing verbatim.
    54 
    55 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    56 "c args == rhs" given in the current context.  (Any number of
    57 arguments may be given on the LHS.)
    58 
    59 
    60 
    61 *** Pure ***
    62 
    63 * class_package.ML offers a combination of axclasses and locales to
    64 achieve Haskell-like type classes in Isabelle. See
    65 HOL/ex/Classpackage.thy for examples.
    66 
    67 * Yet another code generator framework allows to generate executable
    68 code for ML and Haskell (including "class"es). A short usage sketch:
    69 
    70     internal compilation:
    71         code_gen <list of constants (term syntax)> (SML #)
    72     writing SML code to a file:
    73         code_gen <list of constants (term syntax)> (SML <filename>)
    74     writing Haskell code to a bunch of files:
    75         code_gen <list of constants (term syntax)> (Haskell <filename>)
    76 
    77 Reasonable default setup of framework in HOL/Main.
    78 
    79 See HOL/ex/Code*.thy for examples.
    80 
    81 Theorem attributs for selecting and transforming function equations theorems:
    82 
    83     [code fun]:       select a theorem as function equation for a specific constant
    84     [code nofun]:     deselect a theorem as function equation for a specific constant
    85     [code inline]:    select an equation theorem for unfolding (inlining) in place
    86     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    87 
    88 User-defined serializations (target in {SML, Haskell}):
    89 
    90     code_const <and-list of constants (term syntax)>
    91       {(target) <and-list of const target syntax>}+
    92 
    93     code_type <and-list of type constructors>
    94       {(target) <and-list of type target syntax>}+
    95 
    96     code_instance <and-list of instances>
    97       {(target)}+
    98         where instance ::= <type constructor> :: <class>
    99 
   100     code_class <and_list of classes>
   101       {(target) <and-list of class target syntax>}+
   102         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   103 
   104 For code_instance and code_class, target SML is silently ignored.
   105 
   106 See HOL theories and HOL/ex/Code*.thy for usage examples.  Doc/Isar/Advanced/Codegen/
   107 provides a tutorial.
   108 
   109 * Command 'no_translations' removes translation rules from theory
   110 syntax.
   111 
   112 * Overloaded definitions are now actually checked for acyclic
   113 dependencies.  The overloading scheme is slightly more general than
   114 that of Haskell98, although Isabelle does not demand an exact
   115 correspondence to type class and instance declarations.
   116 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   117 exotic versions of overloading -- at the discretion of the user!
   118 
   119 Polymorphic constants are represented via type arguments, i.e. the
   120 instantiation that matches an instance against the most general
   121 declaration given in the signature.  For example, with the declaration
   122 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   123 as c(nat).  Overloading is essentially simultaneous structural
   124 recursion over such type arguments.  Incomplete specification patterns
   125 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   126 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   127 Command 'print_theory' outputs the normalized system of recursive
   128 equations, see section "definitions".
   129 
   130 * Isar: improper proof element 'guess' is like 'obtain', but derives
   131 the obtained context from the course of reasoning!  For example:
   132 
   133   assume "EX x y. A x & B y"   -- "any previous fact"
   134   then guess x and y by clarify
   135 
   136 This technique is potentially adventurous, depending on the facts and
   137 proof tools being involved here.
   138 
   139 * Isar: known facts from the proof context may be specified as literal
   140 propositions, using ASCII back-quote syntax.  This works wherever
   141 named facts used to be allowed so far, in proof commands, proof
   142 methods, attributes etc.  Literal facts are retrieved from the context
   143 according to unification of type and term parameters.  For example,
   144 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   145 theorems in the current context, then these are valid literal facts:
   146 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   147 
   148 There is also a proof method "fact" which does the same composition
   149 for explicit goal states, e.g. the following proof texts coincide with
   150 certain special cases of literal facts:
   151 
   152   have "A" by fact                 ==  note `A`
   153   have "A ==> B" by fact           ==  note `A ==> B`
   154   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   155   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   156 
   157 * Isar: ":" (colon) is no longer a symbolic identifier character in
   158 outer syntax.  Thus symbolic identifiers may be used without
   159 additional white space in declarations like this: ``assume *: A''.
   160 
   161 * Isar: 'print_facts' prints all local facts of the current context,
   162 both named and unnamed ones.
   163 
   164 * Isar: 'def' now admits simultaneous definitions, e.g.:
   165 
   166   def x == "t" and y == "u"
   167 
   168 * Isar: added command 'unfolding', which is structurally similar to
   169 'using', but affects both the goal state and facts by unfolding given
   170 rewrite rules.  Thus many occurrences of the 'unfold' method or
   171 'unfolded' attribute may be replaced by first-class proof text.
   172 
   173 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   174 and command 'unfolding' now all support object-level equalities
   175 (potentially conditional).  The underlying notion of rewrite rule is
   176 analogous to the 'rule_format' attribute, but *not* that of the
   177 Simplifier (which is usually more generous).
   178 
   179 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   180 method expression within a sandbox consisting of the first N
   181 sub-goals, which need to exist.  For example, ``simp_all [3]''
   182 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   183 simplifies all new goals that emerge from applying rule foo to the
   184 originally first one.
   185 
   186 * Isar: schematic goals are no longer restricted to higher-order
   187 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   188 expected.
   189 
   190 * Isar: the conclusion of a long theorem statement is now either
   191 'shows' (a simultaneous conjunction, as before), or 'obtains'
   192 (essentially a disjunction of cases with local parameters and
   193 assumptions).  The latter allows to express general elimination rules
   194 adequately; in this notation common elimination rules look like this:
   195 
   196   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   197     assumes "EX x. P x"
   198     obtains x where "P x"
   199 
   200   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   201     assumes "A & B"
   202     obtains A and B
   203 
   204   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   205     assumes "A | B"
   206     obtains
   207       A
   208     | B
   209 
   210 The subsequent classical rules even refer to the formal "thesis"
   211 explicitly:
   212 
   213   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   214     obtains "~ thesis"
   215 
   216   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   217     obtains "thesis ==> something"
   218 
   219 The actual proof of an 'obtains' statement is analogous to that of the
   220 Isar proof element 'obtain', only that there may be several cases.
   221 Optional case names may be specified in parentheses; these will be
   222 available both in the present proof and as annotations in the
   223 resulting rule, for later use with the 'cases' method (cf. attribute
   224 case_names).
   225 
   226 * Isar: the assumptions of a long theorem statement are available as
   227 "assms" fact in the proof context.  This is more appropriate than the
   228 (historical) "prems", which refers to all assumptions of the current
   229 context, including those from the target locale, proof body etc.
   230 
   231 * Isar: 'print_statement' prints theorems from the current theory or
   232 proof context in long statement form, according to the syntax of a
   233 top-level lemma.
   234 
   235 * Isar: 'obtain' takes an optional case name for the local context
   236 introduction rule (default "that").
   237 
   238 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   239 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   240 to occur.
   241 
   242 * Pure: syntax "CONST name" produces a fully internalized constant
   243 according to the current context.  This is particularly useful for
   244 syntax translations that should refer to internal constant
   245 representations independently of name spaces.
   246 
   247 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   248 instead of "FOO ". This allows multiple binder declarations to coexist
   249 in the same context.  INCOMPATIBILITY.
   250 
   251 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   252 primitive that also works in a locale context (both for constants and
   253 fixed variables).  Type declaration and internal syntactic
   254 representation of given constants retrieved from the context.
   255 
   256 * Isar/locales: new derived specification elements 'axiomatization',
   257 'definition', 'abbreviation', which support type-inference, admit
   258 object-level specifications (equality, equivalence).  See also the
   259 isar-ref manual.  Examples:
   260 
   261   axiomatization
   262     eq  (infix "===" 50) where
   263     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   264 
   265   definition "f x y = x + y + 1"
   266   definition g where "g x = f x x"
   267 
   268   abbreviation
   269     neq  (infix "=!=" 50) where
   270     "x =!= y == ~ (x === y)"
   271 
   272 These specifications may be also used in a locale context.  Then the
   273 constants being introduced depend on certain fixed parameters, and the
   274 constant name is qualified by the locale base name.  An internal
   275 abbreviation takes care for convenient input and output, making the
   276 parameters implicit and using the original short name.  See also
   277 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   278 entities from a monomorphic theory.
   279 
   280 Presently, abbreviations are only available 'in' a target locale, but
   281 not inherited by general import expressions.  Also note that
   282 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   283 'translations' in common applications.
   284 
   285 Concrete syntax is attached to specified constants in internal form,
   286 independently of name spaces.  The parse tree representation is
   287 slightly different -- use 'notation' instead of raw 'syntax', and
   288 'translations' with explicit "CONST" markup to accommodate this.
   289 
   290 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   291 the current context.  Print mode "no_abbrevs" prevents inversion of
   292 abbreviations on output.
   293 
   294 * Isar/locales: improved parameter handling:
   295 - use of locales "var" and "struct" no longer necessary;
   296 - parameter renamings are no longer required to be injective.
   297   This enables, for example, to define a locale for endomorphisms thus:
   298   locale endom = homom mult mult h.
   299 
   300 * Isar/locales: changed the way locales with predicates are defined.
   301 Instead of accumulating the specification, the imported expression is
   302 now an interpretation.
   303 INCOMPATIBILITY: different normal form of locale expressions.
   304 In particular, in interpretations of locales with predicates,
   305 goals repesenting already interpreted fragments are not removed
   306 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   307 
   308 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   309 backward reasoning on locales predicates.  The methods are aware of
   310 interpretations and discharge corresponding goals.  `intro_locales' is
   311 less aggressive then `unfold_locales' and does not unfold predicates to
   312 assumptions.
   313 
   314 * Isar/locales: the order in which locale fragments are accumulated
   315 has changed.  This enables to override declarations from fragments
   316 due to interpretations -- for example, unwanted simp rules.
   317 
   318 * Provers/induct: improved internal context management to support
   319 local fixes and defines on-the-fly.  Thus explicit meta-level
   320 connectives !! and ==> are rarely required anymore in inductive goals
   321 (using object-logic connectives for this purpose has been long
   322 obsolete anyway).  The subsequent proof patterns illustrate advanced
   323 techniques of natural induction; general datatypes and inductive sets
   324 work analogously (see also src/HOL/Lambda for realistic examples).
   325 
   326 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   327 parameters:
   328 
   329   lemma
   330     fixes n :: nat and x :: 'a
   331     assumes a: "A n x"
   332     shows "P n x"
   333     using a                     -- {* make induct insert fact a *}
   334   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   335     case 0
   336     show ?case sorry
   337   next
   338     case (Suc n)
   339     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   340     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   341     show ?case sorry
   342   qed
   343 
   344 (2) This is how to perform induction over ``expressions of a certain
   345 form'', using a locally defined inductive parameter n == "a x"
   346 together with strengthening (the latter is usually required to get
   347 sufficiently flexible induction hypotheses):
   348 
   349   lemma
   350     fixes a :: "'a => nat"
   351     assumes a: "A (a x)"
   352     shows "P (a x)"
   353     using a
   354   proof (induct n == "a x" arbitrary: x)
   355     ...
   356 
   357 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   358 particular technique.
   359 
   360 (3) This is how to perform existential reasoning ('obtains' or
   361 'obtain') by induction, while avoiding explicit object-logic
   362 encodings:
   363 
   364   lemma
   365     fixes n :: nat
   366     obtains x :: 'a where "P n x" and "Q n x"
   367   proof (induct n arbitrary: thesis)
   368     case 0
   369     obtain x where "P 0 x" and "Q 0 x" sorry
   370     then show thesis by (rule 0)
   371   next
   372     case (Suc n)
   373     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   374     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   375     then show thesis by (rule Suc.prems)
   376   qed
   377 
   378 Here the 'arbitrary: thesis' specification essentially modifies the
   379 scope of the formal thesis parameter, in order to the get the whole
   380 existence statement through the induction as expected.
   381 
   382 * Provers/induct: mutual induction rules are now specified as a list
   383 of rule sharing the same induction cases.  HOL packages usually
   384 provide foo_bar.inducts for mutually defined items foo and bar
   385 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   386 specify mutual induction rules differently, i.e. like this:
   387 
   388   (induct rule: foo_bar.inducts)
   389   (induct set: foo bar)
   390   (induct type: foo bar)
   391 
   392 The ML function ProjectRule.projections turns old-style rules into the
   393 new format.
   394 
   395 * Provers/induct: improved handling of simultaneous goals.  Instead of
   396 introducing object-level conjunction, the statement is now split into
   397 several conclusions, while the corresponding symbolic cases are
   398 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   399 explicitly.  For example:
   400 
   401   lemma
   402     fixes n :: nat
   403     shows "P n" and "Q n"
   404   proof (induct n)
   405     case 0 case 1
   406     show "P 0" sorry
   407   next
   408     case 0 case 2
   409     show "Q 0" sorry
   410   next
   411     case (Suc n) case 1
   412     note `P n` and `Q n`
   413     show "P (Suc n)" sorry
   414   next
   415     case (Suc n) case 2
   416     note `P n` and `Q n`
   417     show "Q (Suc n)" sorry
   418   qed
   419 
   420 The split into subcases may be deferred as follows -- this is
   421 particularly relevant for goal statements with local premises.
   422 
   423   lemma
   424     fixes n :: nat
   425     shows "A n ==> P n" and "B n ==> Q n"
   426   proof (induct n)
   427     case 0
   428     {
   429       case 1
   430       note `A 0`
   431       show "P 0" sorry
   432     next
   433       case 2
   434       note `B 0`
   435       show "Q 0" sorry
   436     }
   437   next
   438     case (Suc n)
   439     note `A n ==> P n` and `B n ==> Q n`
   440     {
   441       case 1
   442       note `A (Suc n)`
   443       show "P (Suc n)" sorry
   444     next
   445       case 2
   446       note `B (Suc n)`
   447       show "Q (Suc n)" sorry
   448     }
   449   qed
   450 
   451 If simultaneous goals are to be used with mutual rules, the statement
   452 needs to be structured carefully as a two-level conjunction, using
   453 lists of propositions separated by 'and':
   454 
   455   lemma
   456     shows "a : A ==> P1 a"
   457           "a : A ==> P2 a"
   458       and "b : B ==> Q1 b"
   459           "b : B ==> Q2 b"
   460           "b : B ==> Q3 b"
   461   proof (induct set: A B)
   462 
   463 * Provers/induct: support coinduction as well.  See
   464 src/HOL/Library/Coinductive_List.thy for various examples.
   465 
   466 * Attribute "symmetric" produces result with standardized schematic
   467 variables (index 0).  Potential INCOMPATIBILITY.
   468 
   469 * Simplifier: by default the simplifier trace only shows top level rewrites
   470 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   471 less danger of being flooded by the trace. The trace indicates where parts
   472 have been suppressed.
   473   
   474 * Provers/classical: removed obsolete classical version of elim_format
   475 attribute; classical elim/dest rules are now treated uniformly when
   476 manipulating the claset.
   477 
   478 * Provers/classical: stricter checks to ensure that supplied intro,
   479 dest and elim rules are well-formed; dest and elim rules must have at
   480 least one premise.
   481 
   482 * Provers/classical: attributes dest/elim/intro take an optional
   483 weight argument for the rule (just as the Pure versions).  Weights are
   484 ignored by automated tools, but determine the search order of single
   485 rule steps.
   486 
   487 * Syntax: input syntax now supports dummy variable binding "%_. b",
   488 where the body does not mention the bound variable.  Note that dummy
   489 patterns implicitly depend on their context of bounds, which makes
   490 "{_. _}" match any set comprehension as expected.  Potential
   491 INCOMPATIBILITY -- parse translations need to cope with syntactic
   492 constant "_idtdummy" in the binding position.
   493 
   494 * Syntax: removed obsolete syntactic constant "_K" and its associated
   495 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   496 for example "A -> B" => "Pi A (%_. B)".
   497 
   498 * Pure: 'class_deps' command visualizes the subclass relation, using
   499 the graph browser tool.
   500 
   501 * Pure: 'print_theory' now suppresses entities with internal name
   502 (trailing "_") by default; use '!' option for full details.
   503 
   504 
   505 *** HOL ***
   506 
   507 * New syntactic class "size"; overloaded constant "size" now
   508 has type "'a::size ==> bool"
   509 
   510 * Constants "Divides.op div", "Divides.op mod" and "Divides.op dvd" no named
   511   "Divides.div", "Divides.mod" and "Divides.dvd"
   512   INCOMPATIBILITY for ML code directly refering to constant names.
   513 
   514 * Replaced "auto_term" by the conceptually simpler method "relation",
   515 which just applies the instantiated termination rule with no further
   516 simplifications.
   517 INCOMPATIBILITY: 
   518 Replace 
   519         termination by (auto_term "MYREL")
   520 with 
   521         termination by (relation "MYREL") auto
   522 
   523 * Automated termination proofs "by lexicographic_order" are now
   524 included in the abbreviated function command "fun". No explicit
   525 "termination" command is necessary anymore.
   526 INCOMPATIBILITY: If a "fun"-definition cannot be proved terminating by
   527 a lexicographic size order, then the command fails. Use the expanded
   528 version "function" for these cases.
   529 
   530 * New method "lexicographic_order" automatically synthesizes
   531 termination relations as lexicographic combinations of size measures. 
   532 Usage for (function package) termination proofs:
   533 
   534 termination 
   535 by lexicographic_order
   536 
   537 * Records: generalised field-update to take a function on the field 
   538 rather than the new value: r(|A := x|) is translated to A_update (K x) r
   539 The K-combinator that is internally used is called K_record.
   540 INCOMPATIBILITY: Usage of the plain update functions has to be
   541 adapted.
   542  
   543 * axclass "semiring_0" now contains annihilation axioms 
   544 ("x * 0 = 0","0 * x = 0"), which are required for a semiring. Richer 
   545 structures do not inherit from semiring_0 anymore, because this property 
   546 is a theorem there, not an axiom.
   547 INCOMPATIBILITY: In instances of semiring_0, there is more to prove, but 
   548 this is mostly trivial.
   549 
   550 * axclass "recpower" was generalized to arbitrary monoids, not just 
   551 commutative semirings.
   552 INCOMPATIBILITY: If you use recpower and need commutativity or a semiring
   553 property, add the corresponding classes.
   554 
   555 * Locale Lattic_Locales.partial_order changed (to achieve consistency with
   556   axclass order):
   557   - moved to Orderings.partial_order
   558   - additional parameter ``less''
   559   INCOMPATIBILITY.
   560 
   561 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   562 INCOMPATIBILITY: translations containing list_all2 may go wrong. On Isar
   563 level, use abbreviations instead.
   564 
   565 * Constant "List.op mem" in List.thy now has proper name: "List.memberl"
   566 INCOMPATIBILITY: rarely occuring name references (e.g. ``List.op mem.simps'')
   567 require renaming (e.g. ``List.memberl.simps'').
   568 
   569 * Renamed constants in HOL.thy:
   570     0      ~> HOL.zero
   571     1      ~> HOL.one
   572 INCOMPATIBILITY: ML code directly refering to constant names may need adaption
   573 This in general only affects hand-written proof tactics, simprocs and so on.
   574 
   575 * New theory Code_Generator providing class 'eq',
   576 allowing for code generation with polymorphic equality.
   577 
   578 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has been
   579 abandoned in favour of plain 'int'. INCOMPATIBILITY -- Significant changes
   580 for setting up numeral syntax for types:
   581 
   582   - new constants Numeral.pred and Numeral.succ instead
   583       of former Numeral.bin_pred and Numeral.bin_succ.
   584   - Use integer operations instead of bin_add, bin_mult and so on.
   585   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   586   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   587 
   588 See HOL/Integ/IntArith.thy for an example setup.
   589 
   590 * New top level command 'normal_form' computes the normal form of a term
   591 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   592 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   593 because the functions are compiled to ML first.
   594 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   595 an identifier.
   596 
   597 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   598 25 like -->); output depends on the "iff" print_mode, the default is
   599 "A = B" (with priority 50).
   600 
   601 * Renamed constants in HOL.thy and Orderings.thy:
   602     op +   ~> HOL.plus
   603     op -   ~> HOL.minus
   604     uminus ~> HOL.uminus
   605     op *   ~> HOL.times
   606     op <   ~> Orderings.less
   607     op <=  ~> Orderings.less_eq
   608 
   609 Adaptions may be required in the following cases:
   610 
   611 a) User-defined constants using any of the names "plus", "minus", "times",
   612 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   613 may go wrong.
   614 INCOMPATIBILITY: use more specific names.
   615 
   616 b) Variables named "plus", "minus", "times", "less", "less_eq"
   617 INCOMPATIBILITY: use more specific names.
   618 
   619 c) Permutative equations (e.g. "a + b = b + a")
   620 Since the change of names also changes the order of terms, permutative
   621 rewrite rules may get applied in a different order. Experience shows that
   622 this is rarely the case (only two adaptions in the whole Isabelle
   623 distribution).
   624 INCOMPATIBILITY: rewrite proofs
   625 
   626 d) ML code directly refering to constant names
   627 This in general only affects hand-written proof tactics, simprocs and so on.
   628 INCOMPATIBILITY: grep your sourcecode and replace names.
   629 
   630 * Relations less (<) and less_eq (<=) are also available on type bool.
   631 Modified syntax to disallow nesting without explicit parentheses,
   632 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   633 
   634 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   635 
   636 * Relation composition operator "op O" now has precedence 75 and binds
   637 stronger than union and intersection. INCOMPATIBILITY.
   638 
   639 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   640   Use "{m..<n}" (and relatives) instead.
   641 
   642 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   643 "t = s" to False (by simproc "neq_simproc").  For backward
   644 compatibility this can be disabled by ML "reset use_neq_simproc".
   645 
   646 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   647 
   648 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   649 
   650 * Theorem setsum_mult renamed to setsum_right_distrib.
   651 
   652 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   653 'rule' method.
   654 
   655 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   656 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   657 "=" on type bool) are handled, variable names of the form "lit_<n>"
   658 are no longer reserved, significant speedup.
   659 
   660 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   661 still supported as well.
   662 
   663 * inductive and datatype: provide projections of mutual rules, bundled
   664 as foo_bar.inducts;
   665 
   666 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to Library.
   667 
   668 * Library: moved theory Accessible_Part to main HOL.
   669 
   670 * Library: added theory Coinductive_List of potentially infinite lists
   671 as greatest fixed-point.
   672 
   673 * Library: added theory AssocList which implements (finite) maps as
   674 association lists.
   675 
   676 * New proof method "evaluation" for efficiently solving a goal (i.e. a
   677 boolean expression) by compiling it to ML. The goal is "proved" (via
   678 the oracle "Evaluation") if it evaluates to True.
   679 
   680 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   681 also when invoked by the simplifier.  This results in the simplifier
   682 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   683 fast_arith_split_limit to 0 to obtain the old behavior.
   684 
   685 * Support for hex (0x20) and binary (0b1001) numerals. 
   686 
   687 * New method: reify eqs (t), where eqs are equations for an
   688 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   689 parameter, computes a term s::'b and a list xs::'a list and proves the
   690 theorem I xs s = t. This is also known as reification or quoting. The
   691 resulting theorem is applied to the subgoal to substitute t with I xs
   692 s.  If t is omitted, the subgoal itself is reified.
   693 
   694 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   695 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   696 where f is supposed to be a computable function (in the sense of code
   697 generattion). The method uses reify to compute s and xs as above then
   698 applies corr_thm and uses normalization by evaluation to "prove" f s =
   699 r and finally gets the theorem t = r, which is again applied to the
   700 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   701 
   702 * Reflection: Automatic refification now handels binding, an example
   703 is available in HOL/ex/ReflectionEx.thy
   704 
   705 
   706 *** HOL-Algebra ***
   707 
   708 * Formalisation of ideals and the quotient construction over rings.
   709 
   710 * Order and lattice theory no longer based on records.
   711 INCOMPATIBILITY.
   712 
   713 * Method algebra is now set up via an attribute.  For examples see
   714 CRing.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   715 of algebraic structures.
   716 
   717 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.
   718 
   719 
   720 *** HOL-Complex ***
   721 
   722 * Theory Real: new method ferrack implements quantifier elimination
   723 for linear arithmetic over the reals. The quantifier elimination
   724 feature is used only for decision, for compatibility with arith. This
   725 means a goal is either solved or left unchanged, no simplification.
   726 
   727 
   728 *** ML ***
   729 
   730 * Pure/table:
   731 
   732 Function `...tab.foldl` removed.
   733 INCOMPATIBILITY: use `...tabfold` instead
   734 
   735 * Pure/library:
   736 
   737 `gen_rem(s)` abandoned in favour of `remove` / `subtract`.
   738 INCOMPATIBILITY:
   739 rewrite "gen_rem eq (xs, x)" to "remove (eq o swap) x xs"
   740 rewrite "gen_rems eq (xs, ys)" to "subtract (eq o swap) ys xs"
   741 drop "swap" if "eq" is symmetric.
   742 
   743 * Pure/library:
   744 
   745 infixes `ins` `ins_string` `ins_int` have been abandoned in favour of `insert`.
   746 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"
   747 
   748 * Pure/General/susp.ML:
   749 
   750 New module for delayed evaluations.
   751 
   752 * Pure/library:
   753 
   754 Semantically identical functions "equal_list" and "eq_list" have been
   755 unified to "eq_list".
   756 
   757 * Pure/library:
   758 
   759   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   760   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   761 
   762 The semantics of "burrow" is: "take a function with *simulatanously*
   763 transforms a list of value, and apply it *simulatanously* to a list of
   764 list of values of the appropriate type". Confer this with "map" which
   765 would *not* apply its argument function simulatanously but in
   766 sequence. "fold_burrow" has an additional context.
   767 
   768 Both actually avoid the usage of "unflat" since they hide away
   769 "unflat" from the user.
   770 
   771 * Pure/library: functions map2 and fold2 with curried syntax for
   772 simultanous mapping and folding:
   773 
   774     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   775     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   776 
   777 * Pure/library: indexed lists - some functions in the Isabelle library
   778 treating lists over 'a as finite mappings from [0...n] to 'a have been
   779 given more convenient names and signatures reminiscent of similar
   780 functions for alists, tables, etc:
   781 
   782   val nth: 'a list -> int -> 'a 
   783   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   784   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   785 
   786 Note that fold_index starts counting at index 0, not 1 like foldln
   787 used to.
   788 
   789 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   790 
   791 * Pure/General/name_mangler.ML provides a functor for generic name
   792 mangling (bijective mapping from expression values to strings).
   793 
   794 * Pure/General/rat.ML implements rational numbers.
   795 
   796 * Pure/General/table.ML: the join operations now works via exceptions
   797 DUP/SAME instead of type option.  This is simpler in simple cases, and
   798 admits slightly more efficient complex applications.
   799 
   800 * Pure: datatype Context.generic joins theory/Proof.context and
   801 provides some facilities for code that works in either kind of
   802 context, notably GenericDataFun for uniform theory and proof data.
   803 
   804 * Pure: 'advanced' translation functions (parse_translation etc.) now
   805 use Context.generic instead of just theory.
   806 
   807 * Pure: simplified internal attribute type, which is now always
   808 Context.generic * thm -> Context.generic * thm.  Global (theory)
   809 vs. local (Proof.context) attributes have been discontinued, while
   810 minimizing code duplication.  Thm.rule_attribute and
   811 Thm.declaration_attribute build canonical attributes; see also
   812 structure Context for further operations on Context.generic, notably
   813 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   814 declarations and definitions.
   815 
   816 * Pure/kernel: consts certification ignores sort constraints given in
   817 signature declarations.  (This information is not relevant to the
   818 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   819 
   820 * Pure: axiomatic type classes are now purely definitional, with
   821 explicit proofs of class axioms and super class relations performed
   822 internally.  See Pure/axclass.ML for the main internal interfaces --
   823 notably AxClass.define_class supercedes AxClass.add_axclass, and
   824 AxClass.axiomatize_class/classrel/arity supercede
   825 Sign.add_classes/classrel/arities.
   826 
   827 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   828 global/local versions on theory vs. Proof.context have been
   829 discontinued; Attrib.syntax and Method.syntax have been adapted
   830 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   831 attributes, methods, etc.
   832 
   833 * Pure: several functions of signature "... -> theory -> theory * ..."
   834 have been reoriented to "... -> theory -> ... * theory" in order to
   835 allow natural usage in combination with the ||>, ||>>, |-> and
   836 fold_map combinators.
   837 
   838 * Pure: official theorem names (closed derivations) and additional
   839 comments (tags) are now strictly separate.  Name hints -- which are
   840 maintained as tags -- may be attached any time without affecting the
   841 derivation.
   842 
   843 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   844 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   845 achieve the old behaviour.
   846 
   847 * Pure: the "Goal" constant is now called "prop", supporting a
   848 slightly more general idea of ``protecting'' meta-level rule
   849 statements.
   850 
   851 * Pure: Logic.(un)varify only works in a global context, which is now
   852 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   853 Logic.legacy_(un)varify as temporary workaround.
   854 
   855 * Pure: structure Name provides scalable operations for generating
   856 internal variable names, notably Name.variants etc.  This replaces
   857 some popular functions from term.ML:
   858 
   859   Term.variant		->  Name.variant
   860   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   861   Term.invent_names	->  Name.invent_list
   862 
   863 Note that low-level renaming rarely occurs in new code -- operations
   864 from structure Variable are used instead (see below).
   865 
   866 * Pure: structure Variable provides fundamental operations for proper
   867 treatment of fixed/schematic variables in a context.  For example,
   868 Variable.import introduces fixes for schematics of given facts and
   869 Variable.export reverses the effect (up to renaming) -- this replaces
   870 various freeze_thaw operations.
   871 
   872 * Pure: structure Goal provides simple interfaces for
   873 init/conclude/finish and tactical prove operations (replacing former
   874 Tactic.prove).  Goal.prove is the canonical way to prove results
   875 within a given context; Goal.prove_global is a degraded version for
   876 theory level goals, including a global Drule.standard.  Note that
   877 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   878 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   879 in a locale context).
   880 
   881 * Isar: simplified treatment of user-level errors, using exception
   882 ERROR of string uniformly.  Function error now merely raises ERROR,
   883 without any side effect on output channels.  The Isar toplevel takes
   884 care of proper display of ERROR exceptions.  ML code may use plain
   885 handle/can/try; cat_error may be used to concatenate errors like this:
   886 
   887   ... handle ERROR msg => cat_error msg "..."
   888 
   889 Toplevel ML code (run directly or through the Isar toplevel) may be
   890 embedded into the Isar toplevel with exception display/debug like
   891 this:
   892 
   893   Isar.toplevel (fn () => ...)
   894 
   895 INCOMPATIBILITY, removed special transform_error facilities, removed
   896 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   897 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   898 -- use plain ERROR instead.
   899 
   900 * Isar: theory setup now has type (theory -> theory), instead of a
   901 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   902 
   903 * Isar: installed ML toplevel pretty printer for type Proof.context,
   904 subject to ProofContext.debug/verbose flags.
   905 
   906 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   907 theory before entering a proof state.  Transactions now always see a
   908 quasi-functional intermediate checkpoint, both in interactive and
   909 batch mode.
   910 
   911 * Simplifier: the simpset of a running simplification process now
   912 contains a proof context (cf. Simplifier.the_context), which is the
   913 very context that the initial simpset has been retrieved from (by
   914 simpset_of/local_simpset_of).  Consequently, all plug-in components
   915 (solver, looper etc.) may depend on arbitrary proof data.
   916 
   917 * Simplifier.inherit_context inherits the proof context (plus the
   918 local bounds) of the current simplification process; any simproc
   919 etc. that calls the Simplifier recursively should do this!  Removed
   920 former Simplifier.inherit_bounds, which is already included here --
   921 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   922 specify an explicit context using Simplifier.context/theory_context.
   923 
   924 * Simplifier/Classical Reasoner: more abstract interfaces
   925 change_simpset/claset for modifying the simpset/claset reference of a
   926 theory; raw versions simpset/claset_ref etc. have been discontinued --
   927 INCOMPATIBILITY.
   928 
   929 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   930 "Trueprop" etc.
   931 
   932 
   933 *** System ***
   934 
   935 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   936 locations -- now includes the Isabelle version identifier as well.
   937 This simplifies use of multiple Isabelle installations.
   938 
   939 * isabelle-process: option -S (secure mode) disables some critical
   940 operations, notably runtime compilation and evaluation of ML source
   941 code.
   942 
   943 
   944 New in Isabelle2005 (October 2005)
   945 ----------------------------------
   946 
   947 *** General ***
   948 
   949 * Theory headers: the new header syntax for Isar theories is
   950 
   951   theory <name>
   952   imports <theory1> ... <theoryN>
   953   uses <file1> ... <fileM>
   954   begin
   955 
   956 where the 'uses' part is optional.  The previous syntax
   957 
   958   theory <name> = <theory1> + ... + <theoryN>:
   959 
   960 will disappear in the next release.  Use isatool fixheaders to convert
   961 existing theory files.  Note that there is no change in ancient
   962 non-Isar theories now, but these will disappear soon.
   963 
   964 * Theory loader: parent theories can now also be referred to via
   965 relative and absolute paths.
   966 
   967 * Command 'find_theorems' searches for a list of criteria instead of a
   968 list of constants. Known criteria are: intro, elim, dest, name:string,
   969 simp:term, and any term. Criteria can be preceded by '-' to select
   970 theorems that do not match. Intro, elim, dest select theorems that
   971 match the current goal, name:s selects theorems whose fully qualified
   972 name contain s, and simp:term selects all simplification rules whose
   973 lhs match term.  Any other term is interpreted as pattern and selects
   974 all theorems matching the pattern. Available in ProofGeneral under
   975 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   976 
   977   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   978 
   979 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   980 matching the current goal as introduction rule and not having "HOL."
   981 in their name (i.e. not being defined in theory HOL).
   982 
   983 * Command 'thms_containing' has been discontinued in favour of
   984 'find_theorems'; INCOMPATIBILITY.
   985 
   986 * Communication with Proof General is now 8bit clean, which means that
   987 Unicode text in UTF-8 encoding may be used within theory texts (both
   988 formal and informal parts).  Cf. option -U of the Isabelle Proof
   989 General interface.  Here are some simple examples (cf. src/HOL/ex):
   990 
   991   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   992   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   993 
   994 * Improved efficiency of the Simplifier and, to a lesser degree, the
   995 Classical Reasoner.  Typical big applications run around 2 times
   996 faster.
   997 
   998 
   999 *** Document preparation ***
  1000 
  1001 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1002 of raw sources.  Only those symbols that do not require additional
  1003 LaTeX packages (depending on comments in isabellesym.sty) are
  1004 displayed properly, everything else is left verbatim.  isatool display
  1005 and isatool print are used as front ends (these are subject to the
  1006 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1007 
  1008 * Command tags control specific markup of certain regions of text,
  1009 notably folding and hiding.  Predefined tags include "theory" (for
  1010 theory begin and end), "proof" for proof commands, and "ML" for
  1011 commands involving ML code; the additional tags "visible" and
  1012 "invisible" are unused by default.  Users may give explicit tag
  1013 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1014 interpretation of tags is determined by the LaTeX job during document
  1015 preparation: see option -V of isatool usedir, or options -n and -t of
  1016 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1017 \isadroptag.
  1018 
  1019 Several document versions may be produced at the same time via isatool
  1020 usedir (the generated index.html will link all of them).  Typical
  1021 specifications include ''-V document=theory,proof,ML'' to present
  1022 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1023 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1024 these parts without any formal replacement text.  The Isabelle site
  1025 default settings produce ''document'' and ''outline'' versions as
  1026 specified above.
  1027 
  1028 * Several new antiquotations:
  1029 
  1030   @{term_type term} prints a term with its type annotated;
  1031 
  1032   @{typeof term} prints the type of a term;
  1033 
  1034   @{const const} is the same as @{term const}, but checks that the
  1035   argument is a known logical constant;
  1036 
  1037   @{term_style style term} and @{thm_style style thm} print a term or
  1038   theorem applying a "style" to it
  1039 
  1040   @{ML text}
  1041 
  1042 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1043 definitions, equations, inequations etc., 'concl' printing only the
  1044 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1045 to print the specified premise.  TermStyle.add_style provides an ML
  1046 interface for introducing further styles.  See also the "LaTeX Sugar"
  1047 document practical applications.  The ML antiquotation prints
  1048 type-checked ML expressions verbatim.
  1049 
  1050 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1051 and 'text' support optional locale specification '(in loc)', which
  1052 specifies the default context for interpreting antiquotations.  For
  1053 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1054 
  1055 * Option 'locale=NAME' of antiquotations specifies an alternative
  1056 context interpreting the subsequent argument.  For example: @{thm
  1057 [locale=lattice] inf_assoc}.
  1058 
  1059 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1060 a proof context.
  1061 
  1062 * Proper output of antiquotations for theory commands involving a
  1063 proof context (such as 'locale' or 'theorem (in loc) ...').
  1064 
  1065 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1066 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1067 
  1068 * isatool usedir: new option -C (default true) controls whether option
  1069 -D should include a copy of the original document directory; -C false
  1070 prevents unwanted effects such as copying of administrative CVS data.
  1071 
  1072 
  1073 *** Pure ***
  1074 
  1075 * Considerably improved version of 'constdefs' command.  Now performs
  1076 automatic type-inference of declared constants; additional support for
  1077 local structure declarations (cf. locales and HOL records), see also
  1078 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1079 sequential dependencies of definitions within a single 'constdefs'
  1080 section; moreover, the declared name needs to be an identifier.  If
  1081 all fails, consider to fall back on 'consts' and 'defs' separately.
  1082 
  1083 * Improved indexed syntax and implicit structures.  First of all,
  1084 indexed syntax provides a notational device for subscripted
  1085 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1086 expressions.  Secondly, in a local context with structure
  1087 declarations, number indexes \<^sub>n or the empty index (default
  1088 number 1) refer to a certain fixed variable implicitly; option
  1089 show_structs controls printing of implicit structures.  Typical
  1090 applications of these concepts involve record types and locales.
  1091 
  1092 * New command 'no_syntax' removes grammar declarations (and
  1093 translations) resulting from the given syntax specification, which is
  1094 interpreted in the same manner as for the 'syntax' command.
  1095 
  1096 * 'Advanced' translation functions (parse_translation etc.) may depend
  1097 on the signature of the theory context being presently used for
  1098 parsing/printing, see also isar-ref manual.
  1099 
  1100 * Improved 'oracle' command provides a type-safe interface to turn an
  1101 ML expression of type theory -> T -> term into a primitive rule of
  1102 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1103 is already included here); see also FOL/ex/IffExample.thy;
  1104 INCOMPATIBILITY.
  1105 
  1106 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1107 before); "cI" is no longer bound, use "c.intro" instead.
  1108 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1109 axclasses vs. locales.
  1110 
  1111 * Improved internal renaming of symbolic identifiers -- attach primes
  1112 instead of base 26 numbers.
  1113 
  1114 * New flag show_question_marks controls printing of leading question
  1115 marks in schematic variable names.
  1116 
  1117 * In schematic variable names, *any* symbol following \<^isub> or
  1118 \<^isup> is now treated as part of the base name.  For example, the
  1119 following works without printing of awkward ".0" indexes:
  1120 
  1121   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1122     by simp
  1123 
  1124 * Inner syntax includes (*(*nested*) comments*).
  1125 
  1126 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1127 annotations as "(00...)".
  1128 
  1129 * Clear separation of logical types and nonterminals, where the latter
  1130 may only occur in 'syntax' specifications or type abbreviations.
  1131 Before that distinction was only partially implemented via type class
  1132 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1133 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1134 exotic syntax specifications may require further adaption
  1135 (e.g. Cube/Cube.thy).
  1136 
  1137 * Removed obsolete type class "logic", use the top sort {} instead.
  1138 Note that non-logical types should be declared as 'nonterminals'
  1139 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1140 specifications.
  1141 
  1142 * Attributes 'induct' and 'cases': type or set names may now be
  1143 locally fixed variables as well.
  1144 
  1145 * Simplifier: can now control the depth to which conditional rewriting
  1146 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1147 Limit.
  1148 
  1149 * Simplifier: simplification procedures may now take the current
  1150 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1151 interface), which is very useful for calling the Simplifier
  1152 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1153 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1154 low-level mk_simproc no longer applies Logic.varify internally, to
  1155 allow for use in a context of fixed variables.
  1156 
  1157 * thin_tac now works even if the assumption being deleted contains !!
  1158 or ==>.  More generally, erule now works even if the major premise of
  1159 the elimination rule contains !! or ==>.
  1160 
  1161 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1162 
  1163 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1164 from Pure, which contains all common declarations already.  Both
  1165 theories are defined via plain Isabelle/Isar .thy files.
  1166 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1167 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1168 use isatool fixcpure to adapt your theory and ML sources.
  1169 
  1170 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1171 selections of theorems in named facts via index ranges.
  1172 
  1173 * 'print_theorems': in theory mode, really print the difference
  1174 wrt. the last state (works for interactive theory development only),
  1175 in proof mode print all local facts (cf. 'print_facts');
  1176 
  1177 * 'hide': option '(open)' hides only base names.
  1178 
  1179 * More efficient treatment of intermediate checkpoints in interactive
  1180 theory development.
  1181 
  1182 * Code generator is now invoked via code_module (incremental code
  1183 generation) and code_library (modular code generation, ML structures
  1184 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1185 must be quoted when used as identifiers.
  1186 
  1187 * New 'value' command for reading, evaluating and printing terms using
  1188 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1189 quoted when used as identifier.
  1190 
  1191 
  1192 *** Locales ***
  1193 
  1194 * New commands for the interpretation of locale expressions in
  1195 theories (1), locales (2) and proof contexts (3).  These generate
  1196 proof obligations from the expression specification.  After the
  1197 obligations have been discharged, theorems of the expression are added
  1198 to the theory, target locale or proof context.  The synopsis of the
  1199 commands is a follows:
  1200 
  1201   (1) interpretation expr inst
  1202   (2) interpretation target < expr
  1203   (3) interpret expr inst
  1204 
  1205 Interpretation in theories and proof contexts require a parameter
  1206 instantiation of terms from the current context.  This is applied to
  1207 specifications and theorems of the interpreted expression.
  1208 Interpretation in locales only permits parameter renaming through the
  1209 locale expression.  Interpretation is smart in that interpretations
  1210 that are active already do not occur in proof obligations, neither are
  1211 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1212 inspect active interpretations of a particular locale.  For details,
  1213 see the Isar Reference manual.  Examples can be found in
  1214 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1215 
  1216 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1217 'interpret' instead.
  1218 
  1219 * New context element 'constrains' for adding type constraints to
  1220 parameters.
  1221 
  1222 * Context expressions: renaming of parameters with syntax
  1223 redeclaration.
  1224 
  1225 * Locale declaration: 'includes' disallowed.
  1226 
  1227 * Proper static binding of attribute syntax -- i.e. types / terms /
  1228 facts mentioned as arguments are always those of the locale definition
  1229 context, independently of the context of later invocations.  Moreover,
  1230 locale operations (renaming and type / term instantiation) are applied
  1231 to attribute arguments as expected.
  1232 
  1233 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1234 actual attributes; rare situations may require Attrib.attribute to
  1235 embed those attributes into Attrib.src that lack concrete syntax.
  1236 Attribute implementations need to cooperate properly with the static
  1237 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1238 Attrib.XXX_thm etc. already do the right thing without further
  1239 intervention.  Only unusual applications -- such as "where" or "of"
  1240 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1241 on the context and the facts involved -- may have to assign parsed
  1242 values to argument tokens explicitly.
  1243 
  1244 * Changed parameter management in theorem generation for long goal
  1245 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1246 theorem statement in rare situations.
  1247 
  1248 * Locale inspection command 'print_locale' omits notes elements.  Use
  1249 'print_locale!' to have them included in the output.
  1250 
  1251 
  1252 *** Provers ***
  1253 
  1254 * Provers/hypsubst.ML: improved version of the subst method, for
  1255 single-step rewriting: it now works in bound variable contexts. New is
  1256 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1257 rewrite a different subterm than the original subst method, which is
  1258 still available as 'simplesubst'.
  1259 
  1260 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1261 and quasi orders.
  1262 
  1263 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1264 reflexive-transitive closure of relations.
  1265 
  1266 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1267 limit (previously hard-coded with a value of 20) user-definable.
  1268 
  1269 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1270 is peformed already.  Object-logics merely need to finish their
  1271 initial simpset configuration as before.  INCOMPATIBILITY.
  1272 
  1273 
  1274 *** HOL ***
  1275 
  1276 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1277 
  1278   syntax (epsilon)
  1279     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1280 
  1281 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1282 and x-symbol; use option '-m epsilon' to get it actually printed.
  1283 Moreover, the mathematically important symbolic identifier \<epsilon>
  1284 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1285 
  1286 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1287 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1288 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1289 support corresponding Isar calculations.
  1290 
  1291 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1292 instead of ":".
  1293 
  1294 * theory SetInterval: changed the syntax for open intervals:
  1295 
  1296   Old       New
  1297   {..n(}    {..<n}
  1298   {)n..}    {n<..}
  1299   {m..n(}   {m..<n}
  1300   {)m..n}   {m<..n}
  1301   {)m..n(}  {m<..<n}
  1302 
  1303 The old syntax is still supported but will disappear in the next
  1304 release.  For conversion use the following Emacs search and replace
  1305 patterns (these are not perfect but work quite well):
  1306 
  1307   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1308   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1309 
  1310 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1311 equalities in commutative rings; method 'algebra' provides a generic
  1312 interface.
  1313 
  1314 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1315 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1316 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1317 be a tuple pattern.
  1318 
  1319 Some new syntax forms are available:
  1320 
  1321   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1322   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1323   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1324   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1325 
  1326 The latter form "\<Sum>x < k. e" used to be based on a separate
  1327 function "Summation", which has been discontinued.
  1328 
  1329 * theory Finite_Set: in structured induction proofs, the insert case
  1330 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1331 (insert F x)'.
  1332 
  1333 * The 'refute' command has been extended to support a much larger
  1334 fragment of HOL, including axiomatic type classes, constdefs and
  1335 typedefs, inductive datatypes and recursion.
  1336 
  1337 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1338 Requires zChaff with proof generation to be installed.  See
  1339 HOL/ex/SAT_Examples.thy for examples.
  1340 
  1341 * Datatype induction via method 'induct' now preserves the name of the
  1342 induction variable. For example, when proving P(xs::'a list) by
  1343 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1344 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1345 in unstructured proof scripts.
  1346 
  1347 * Reworked implementation of records.  Improved scalability for
  1348 records with many fields, avoiding performance problems for type
  1349 inference. Records are no longer composed of nested field types, but
  1350 of nested extension types. Therefore the record type only grows linear
  1351 in the number of extensions and not in the number of fields.  The
  1352 top-level (users) view on records is preserved.  Potential
  1353 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1354 old record representation. The type generated for a record is called
  1355 <record_name>_ext_type.
  1356 
  1357 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1358 proofs triggered by a record definition or a simproc (if
  1359 quick_and_dirty is enabled).  Definitions of large records can take
  1360 quite long.
  1361 
  1362 New simproc record_upd_simproc for simplification of multiple record
  1363 updates enabled by default.  Moreover, trivial updates are also
  1364 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1365 occasionally, since simplification is more powerful by default.
  1366 
  1367 * typedef: proper support for polymorphic sets, which contain extra
  1368 type-variables in the term.
  1369 
  1370 * Simplifier: automatically reasons about transitivity chains
  1371 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1372 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1373 old proofs break occasionally as simplification may now solve more
  1374 goals than previously.
  1375 
  1376 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1377 present.  Works for all partial orders (class "order"), in particular
  1378 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1379 just like y <= x.
  1380 
  1381 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1382 bound variable or a constant then the let is unfolded.  Otherwise
  1383 first a is simplified to b, and then f b is simplified to g. If
  1384 possible we abstract b from g arriving at "let x = b in h x",
  1385 otherwise we unfold the let and arrive at g.  The simproc can be
  1386 enabled/disabled by the reference use_let_simproc.  Potential
  1387 INCOMPATIBILITY since simplification is more powerful by default.
  1388 
  1389 * Classical reasoning: the meson method now accepts theorems as arguments.
  1390 
  1391 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1392 jobs to provide advice on the provability of subgoals.
  1393 
  1394 * Theory OrderedGroup and Ring_and_Field: various additions and
  1395 improvements to faciliate calculations involving equalities and
  1396 inequalities.
  1397 
  1398 The following theorems have been eliminated or modified
  1399 (INCOMPATIBILITY):
  1400 
  1401   abs_eq             now named abs_of_nonneg
  1402   abs_of_ge_0        now named abs_of_nonneg
  1403   abs_minus_eq       now named abs_of_nonpos
  1404   imp_abs_id         now named abs_of_nonneg
  1405   imp_abs_neg_id     now named abs_of_nonpos
  1406   mult_pos           now named mult_pos_pos
  1407   mult_pos_le        now named mult_nonneg_nonneg
  1408   mult_pos_neg_le    now named mult_nonneg_nonpos
  1409   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1410   mult_neg           now named mult_neg_neg
  1411   mult_neg_le        now named mult_nonpos_nonpos
  1412 
  1413 * Theory Parity: added rules for simplifying exponents.
  1414 
  1415 * Theory List:
  1416 
  1417 The following theorems have been eliminated or modified
  1418 (INCOMPATIBILITY):
  1419 
  1420   list_all_Nil       now named list_all.simps(1)
  1421   list_all_Cons      now named list_all.simps(2)
  1422   list_all_conv      now named list_all_iff
  1423   set_mem_eq         now named mem_iff
  1424 
  1425 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1426 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1427 
  1428 
  1429 *** HOL-Complex ***
  1430 
  1431 * Theory RealDef: better support for embedding natural numbers and
  1432 integers in the reals.
  1433 
  1434 The following theorems have been eliminated or modified
  1435 (INCOMPATIBILITY):
  1436 
  1437   exp_ge_add_one_self  now requires no hypotheses
  1438   real_of_int_add      reversed direction of equality (use [symmetric])
  1439   real_of_int_minus    reversed direction of equality (use [symmetric])
  1440   real_of_int_diff     reversed direction of equality (use [symmetric])
  1441   real_of_int_mult     reversed direction of equality (use [symmetric])
  1442 
  1443 * Theory RComplete: expanded support for floor and ceiling functions.
  1444 
  1445 * Theory Ln is new, with properties of the natural logarithm
  1446 
  1447 * Hyperreal: There is a new type constructor "star" for making
  1448 nonstandard types.  The old type names are now type synonyms:
  1449 
  1450   hypreal = real star
  1451   hypnat = nat star
  1452   hcomplex = complex star
  1453 
  1454 * Hyperreal: Many groups of similarly-defined constants have been
  1455 replaced by polymorphic versions (INCOMPATIBILITY):
  1456 
  1457   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1458 
  1459   starset      <-- starsetNat, starsetC
  1460   *s*          <-- *sNat*, *sc*
  1461   starset_n    <-- starsetNat_n, starsetC_n
  1462   *sn*         <-- *sNatn*, *scn*
  1463   InternalSets <-- InternalNatSets, InternalCSets
  1464 
  1465   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1466   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1467   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1468   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1469   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1470 
  1471 * Hyperreal: Many type-specific theorems have been removed in favor of
  1472 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1473 
  1474   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1475   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1476   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1477   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1478   right_minus <-- hypreal_add_minus
  1479   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1480   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1481   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1482   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1483   mult_1_right <-- hcomplex_mult_one_right
  1484   mult_zero_left <-- hcomplex_mult_zero_left
  1485   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1486   right_distrib <-- hypnat_add_mult_distrib2
  1487   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1488   right_inverse <-- hypreal_mult_inverse
  1489   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1490   order_refl <-- {hypreal,hypnat}_le_refl
  1491   order_trans <-- {hypreal,hypnat}_le_trans
  1492   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1493   order_less_le <-- {hypreal,hypnat}_less_le
  1494   linorder_linear <-- {hypreal,hypnat}_le_linear
  1495   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1496   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1497   add_nonneg_nonneg <-- hypreal_le_add_order
  1498 
  1499 * Hyperreal: Separate theorems having to do with type-specific
  1500 versions of constants have been merged into theorems that apply to the
  1501 new polymorphic constants (INCOMPATIBILITY):
  1502 
  1503   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1504   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1505   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1506   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1507   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1508   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1509   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1510   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1511   STAR_diff <-- {STAR,STARC}_diff
  1512   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1513     STARC_hcomplex_of_complex}_image_subset
  1514   starset_n_Un <-- starset{Nat,C}_n_Un
  1515   starset_n_Int <-- starset{Nat,C}_n_Int
  1516   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1517   starset_n_diff <-- starset{Nat,C}_n_diff
  1518   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1519   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1520   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1521   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1522   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1523   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1524   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1525   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1526   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1527   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1528   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1529   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1530   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1531   starfun_diff <-- starfun{C,RC,CR}_diff
  1532   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1533   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1534   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1535   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1536   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1537   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1538   starfun_Id <-- starfunC_Id
  1539   starfun_approx <-- starfun{Nat,CR}_approx
  1540   starfun_capprox <-- starfun{C,RC}_capprox
  1541   starfun_abs <-- starfunNat_rabs
  1542   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1543   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1544   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1545   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1546   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1547   starfun_add_approx <-- starfunCR_add_approx
  1548   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1549   starfun_divide <-- starfun{C,CR,RC}_divide
  1550   starfun_n <-- starfun{Nat,C}_n
  1551   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1552   starfun_n_add <-- starfun{Nat,C}_n_add
  1553   starfun_n_add_minus <-- starfunNat_n_add_minus
  1554   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1555   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1556   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1557 
  1558   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1559   star_n_minus <-- {hypreal,hcomplex}_minus
  1560   star_n_diff <-- {hypreal,hcomplex}_diff
  1561   star_n_mult <-- {hypreal,hcomplex}_mult
  1562   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1563   star_n_le <-- {hypreal,hypnat}_le
  1564   star_n_less <-- {hypreal,hypnat}_less
  1565   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1566   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1567   star_n_abs <-- hypreal_hrabs
  1568   star_n_divide <-- hcomplex_divide
  1569 
  1570   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1571   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1572   star_of_diff <-- hypreal_of_real_diff
  1573   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1574   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1575   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1576   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1577   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1578   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1579   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1580   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1581   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1582   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1583   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1584   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1585   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1586   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1587   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1588   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1589   star_of_power <-- hypreal_of_real_power
  1590   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1591 
  1592 * Hyperreal: new method "transfer" that implements the transfer
  1593 principle of nonstandard analysis. With a subgoal that mentions
  1594 nonstandard types like "'a star", the command "apply transfer"
  1595 replaces it with an equivalent one that mentions only standard types.
  1596 To be successful, all free variables must have standard types; non-
  1597 standard variables must have explicit universal quantifiers.
  1598 
  1599 * Hyperreal: A theory of Taylor series.
  1600 
  1601 
  1602 *** HOLCF ***
  1603 
  1604 * Discontinued special version of 'constdefs' (which used to support
  1605 continuous functions) in favor of the general Pure one with full
  1606 type-inference.
  1607 
  1608 * New simplification procedure for solving continuity conditions; it
  1609 is much faster on terms with many nested lambda abstractions (cubic
  1610 instead of exponential time).
  1611 
  1612 * New syntax for domain package: selector names are now optional.
  1613 Parentheses should be omitted unless argument is lazy, for example:
  1614 
  1615   domain 'a stream = cons "'a" (lazy "'a stream")
  1616 
  1617 * New command 'fixrec' for defining recursive functions with pattern
  1618 matching; defining multiple functions with mutual recursion is also
  1619 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1620 sinr, or any data constructor defined by the domain package. The given
  1621 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1622 syntax and examples.
  1623 
  1624 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1625 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1626 but the proof obligation additionally includes an admissibility
  1627 requirement. The packages generate instances of class cpo or pcpo,
  1628 with continuity and strictness theorems for Rep and Abs.
  1629 
  1630 * HOLCF: Many theorems have been renamed according to a more standard naming
  1631 scheme (INCOMPATIBILITY):
  1632 
  1633   foo_inject:  "foo$x = foo$y ==> x = y"
  1634   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1635   foo_less:    "(foo$x << foo$y) = (x << y)"
  1636   foo_strict:  "foo$UU = UU"
  1637   foo_defined: "... ==> foo$x ~= UU"
  1638   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1639 
  1640 
  1641 *** ZF ***
  1642 
  1643 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1644 including the First Isomorphism Theorem (on quotienting by the kernel
  1645 of a homomorphism).
  1646 
  1647 * ZF/Simplifier: install second copy of type solver that actually
  1648 makes use of TC rules declared to Isar proof contexts (or locales);
  1649 the old version is still required for ML proof scripts.
  1650 
  1651 
  1652 *** Cube ***
  1653 
  1654 * Converted to Isar theory format; use locales instead of axiomatic
  1655 theories.
  1656 
  1657 
  1658 *** ML ***
  1659 
  1660 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1661 for ||>, ||>>, |>>,
  1662 
  1663 * Pure/library.ML no longer defines its own option datatype, but uses
  1664 that of the SML basis, which has constructors NONE and SOME instead of
  1665 None and Some, as well as exception Option.Option instead of OPTION.
  1666 The functions the, if_none, is_some, is_none have been adapted
  1667 accordingly, while Option.map replaces apsome.
  1668 
  1669 * Pure/library.ML: the exception LIST has been given up in favour of
  1670 the standard exceptions Empty and Subscript, as well as
  1671 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1672 superceded by the standard hd and tl functions etc.
  1673 
  1674 A number of basic list functions are no longer exported to the ML
  1675 toplevel, as they are variants of predefined functions.  The following
  1676 suggests how one can translate existing code:
  1677 
  1678     rev_append xs ys = List.revAppend (xs, ys)
  1679     nth_elem (i, xs) = List.nth (xs, i)
  1680     last_elem xs = List.last xs
  1681     flat xss = List.concat xss
  1682     seq fs = List.app fs
  1683     partition P xs = List.partition P xs
  1684     mapfilter f xs = List.mapPartial f xs
  1685 
  1686 * Pure/library.ML: several combinators for linear functional
  1687 transformations, notably reverse application and composition:
  1688 
  1689   x |> f                f #> g
  1690   (x, y) |-> f          f #-> g
  1691 
  1692 * Pure/library.ML: introduced/changed precedence of infix operators:
  1693 
  1694   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1695   infix 2 ?;
  1696   infix 3 o oo ooo oooo;
  1697   infix 4 ~~ upto downto;
  1698 
  1699 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1700 infix operators.
  1701 
  1702 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1703 fold_map support linear functional transformations and nesting.  For
  1704 example:
  1705 
  1706   fold f [x1, ..., xN] y =
  1707     y |> f x1 |> ... |> f xN
  1708 
  1709   (fold o fold) f [xs1, ..., xsN] y =
  1710     y |> fold f xs1 |> ... |> fold f xsN
  1711 
  1712   fold f [x1, ..., xN] =
  1713     f x1 #> ... #> f xN
  1714 
  1715   (fold o fold) f [xs1, ..., xsN] =
  1716     fold f xs1 #> ... #> fold f xsN
  1717 
  1718 * Pure/library.ML: the following selectors on type 'a option are
  1719 available:
  1720 
  1721   the:               'a option -> 'a  (*partial*)
  1722   these:             'a option -> 'a  where 'a = 'b list
  1723   the_default: 'a -> 'a option -> 'a
  1724   the_list:          'a option -> 'a list
  1725 
  1726 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1727 basic operations for association lists, following natural argument
  1728 order; moreover the explicit equality predicate passed here avoids
  1729 potentially expensive polymorphic runtime equality checks.
  1730 The old functions may be expressed as follows:
  1731 
  1732   assoc = uncurry (AList.lookup (op =))
  1733   assocs = these oo AList.lookup (op =)
  1734   overwrite = uncurry (AList.update (op =)) o swap
  1735 
  1736 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1737 
  1738   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1739   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1740 
  1741 replacing make_keylist and keyfilter (occassionally used)
  1742 Naive rewrites:
  1743 
  1744   make_keylist = AList.make
  1745   keyfilter = AList.find (op =)
  1746 
  1747 * eq_fst and eq_snd now take explicit equality parameter, thus
  1748   avoiding eqtypes. Naive rewrites:
  1749 
  1750     eq_fst = eq_fst (op =)
  1751     eq_snd = eq_snd (op =)
  1752 
  1753 * Removed deprecated apl and apr (rarely used).
  1754   Naive rewrites:
  1755 
  1756     apl (n, op) =>>= curry op n
  1757     apr (op, m) =>>= fn n => op (n, m)
  1758 
  1759 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1760 provides a reasonably efficient light-weight implementation of sets as
  1761 lists.
  1762 
  1763 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1764 few new operations; existing lookup and update are now curried to
  1765 follow natural argument order (for use with fold etc.);
  1766 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1767 
  1768 * Pure/General: output via the Isabelle channels of
  1769 writeln/warning/error etc. is now passed through Output.output, with a
  1770 hook for arbitrary transformations depending on the print_mode
  1771 (cf. Output.add_mode -- the first active mode that provides a output
  1772 function wins).  Already formatted output may be embedded into further
  1773 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1774 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1775 accommodate easy composition of diagnostic messages etc.  Programmers
  1776 rarely need to care about Output.output or Output.raw at all, with
  1777 some notable exceptions: Output.output is required when bypassing the
  1778 standard channels (writeln etc.), or in token translations to produce
  1779 properly formatted results; Output.raw is required when capturing
  1780 already output material that will eventually be presented to the user
  1781 a second time.  For the default print mode, both Output.output and
  1782 Output.raw have no effect.
  1783 
  1784 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1785 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1786 cumulative results are displayed at the end of a batch session.
  1787 
  1788 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1789 replaced by File.platform_path and File.shell_path (with appropriate
  1790 hooks).  This provides a clean interface for unusual systems where the
  1791 internal and external process view of file names are different.
  1792 
  1793 * Pure: more efficient orders for basic syntactic entities: added
  1794 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1795 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1796 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1797 orders now -- potential INCOMPATIBILITY for code that depends on a
  1798 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1799 Library.sort_strings on result).
  1800 
  1801 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1802 fold_types traverse types/terms from left to right, observing natural
  1803 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1804 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1805 
  1806 * Pure: name spaces have been refined, with significant changes of the
  1807 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1808 to extern(_table).  The plain name entry path is superceded by a
  1809 general 'naming' context, which also includes the 'policy' to produce
  1810 a fully qualified name and external accesses of a fully qualified
  1811 name; NameSpace.extend is superceded by context dependent
  1812 Sign.declare_name.  Several theory and proof context operations modify
  1813 the naming context.  Especially note Theory.restore_naming and
  1814 ProofContext.restore_naming to get back to a sane state; note that
  1815 Theory.add_path is no longer sufficient to recover from
  1816 Theory.absolute_path in particular.
  1817 
  1818 * Pure: new flags short_names (default false) and unique_names
  1819 (default true) for controlling output of qualified names.  If
  1820 short_names is set, names are printed unqualified.  If unique_names is
  1821 reset, the name prefix is reduced to the minimum required to achieve
  1822 the original result when interning again, even if there is an overlap
  1823 with earlier declarations.
  1824 
  1825 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1826 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1827 (useful for printing error messages).  INCOMPATIBILITY.
  1828 
  1829 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1830 Theory.theory are now identified, referring to the universal
  1831 Context.theory (see Pure/context.ML).  Actual signature and theory
  1832 content is managed as theory data.  The old code and interfaces were
  1833 spread over many files and structures; the new arrangement introduces
  1834 considerable INCOMPATIBILITY to gain more clarity:
  1835 
  1836   Context -- theory management operations (name, identity, inclusion,
  1837     parents, ancestors, merge, etc.), plus generic theory data;
  1838 
  1839   Sign -- logical signature and syntax operations (declaring consts,
  1840     types, etc.), plus certify/read for common entities;
  1841 
  1842   Theory -- logical theory operations (stating axioms, definitions,
  1843     oracles), plus a copy of logical signature operations (consts,
  1844     types, etc.); also a few basic management operations (Theory.copy,
  1845     Theory.merge, etc.)
  1846 
  1847 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1848 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1849 for convenience -- they merely return the theory.
  1850 
  1851 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1852 
  1853 * Pure: the Isar proof context type is already defined early in Pure
  1854 as Context.proof (note that ProofContext.context and Proof.context are
  1855 aliases, where the latter is the preferred name).  This enables other
  1856 Isabelle components to refer to that type even before Isar is present.
  1857 
  1858 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1859 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1860 any of these kinds.  For example, Sign.intern typeK is now
  1861 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1862 Theory.hide_types.  Also note that former
  1863 Theory.hide_classes/types/consts are now
  1864 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1865 internalize their arguments!  INCOMPATIBILITY.
  1866 
  1867 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1868 datatype thmref (with constructors Name and NameSelection) instead of
  1869 plain string -- INCOMPATIBILITY;
  1870 
  1871 * Pure: cases produced by proof methods specify options, where NONE
  1872 means to remove case bindings -- INCOMPATIBILITY in
  1873 (RAW_)METHOD_CASES.
  1874 
  1875 * Pure: the following operations retrieve axioms or theorems from a
  1876 theory node or theory hierarchy, respectively:
  1877 
  1878   Theory.axioms_of: theory -> (string * term) list
  1879   Theory.all_axioms_of: theory -> (string * term) list
  1880   PureThy.thms_of: theory -> (string * thm) list
  1881   PureThy.all_thms_of: theory -> (string * thm) list
  1882 
  1883 * Pure: print_tac now outputs the goal through the trace channel.
  1884 
  1885 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1886 Reference Toplevel.debug (default false) controls detailed printing
  1887 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1888 controls execution profiling -- set to 1 for time and 2 for space
  1889 (both increase the runtime).
  1890 
  1891 * Isar session: The initial use of ROOT.ML is now always timed,
  1892 i.e. the log will show the actual process times, in contrast to the
  1893 elapsed wall-clock time that the outer shell wrapper produces.
  1894 
  1895 * Simplifier: improved handling of bound variables (nameless
  1896 representation, avoid allocating new strings).  Simprocs that invoke
  1897 the Simplifier recursively should use Simplifier.inherit_bounds to
  1898 avoid local name clashes.  Failure to do so produces warnings
  1899 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1900 for further details.
  1901 
  1902 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1903 bindings for all theorems stored within a given theory; this may help
  1904 in porting non-Isar theories to Isar ones, while keeping ML proof
  1905 scripts for the time being.
  1906 
  1907 * ML operator HTML.with_charset specifies the charset begin used for
  1908 generated HTML files.  For example:
  1909 
  1910   HTML.with_charset "utf-8" use_thy "Hebrew";
  1911   HTML.with_charset "utf-8" use_thy "Chinese";
  1912 
  1913 
  1914 *** System ***
  1915 
  1916 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1917 isabelle, isatool etc.).
  1918 
  1919 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1920 isatool doc, isatool mkdir, display_drafts etc.).
  1921 
  1922 * isatool usedir: option -f allows specification of the ML file to be
  1923 used by Isabelle; default is ROOT.ML.
  1924 
  1925 * New isatool version outputs the version identifier of the Isabelle
  1926 distribution being used.
  1927 
  1928 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1929 (containing Boolean satisfiability problems) into Isabelle/HOL
  1930 theories.
  1931 
  1932 
  1933 
  1934 New in Isabelle2004 (April 2004)
  1935 --------------------------------
  1936 
  1937 *** General ***
  1938 
  1939 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1940   Replaces linorder.ML.
  1941 
  1942 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1943   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1944   (\<a>...\<z>), are now considered normal letters, and can therefore
  1945   be used anywhere where an ASCII letter (a...zA...Z) has until
  1946   now. COMPATIBILITY: This obviously changes the parsing of some
  1947   terms, especially where a symbol has been used as a binder, say
  1948   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1949   as an identifier.  Fix it by inserting a space around former
  1950   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1951   existing theory and ML files.
  1952 
  1953 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1954 
  1955 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1956   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1957   a normal (but invisible) letter. For multiple letter subscripts repeat
  1958   \<^isub> like this: x\<^isub>1\<^isub>2.
  1959 
  1960 * Pure: There are now sub-/superscripts that can span more than one
  1961   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1962   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1963   superscript. The new control characters are not identifier parts.
  1964 
  1965 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1966   content of "..." to the latex file instead of \isacntrl... . The "..."
  1967   may consist of any printable characters excluding the end bracket >.
  1968 
  1969 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1970   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1971   declare constants "final", which prevents their being given a definition
  1972   later.  It is useful for constants whose behaviour is fixed axiomatically
  1973   rather than definitionally, such as the meta-logic connectives.
  1974 
  1975 * Pure: 'instance' now handles general arities with general sorts
  1976   (i.e. intersections of classes),
  1977 
  1978 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1979   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1980   It can be changed to alter the colors/layout of generated pages.
  1981 
  1982 
  1983 *** Isar ***
  1984 
  1985 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1986   cut_tac, subgoal_tac and thin_tac:
  1987   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1988     locales are no longer forced to write Isar proof scripts.
  1989     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1990     emulations.
  1991   - INCOMPATIBILITY: names of variables to be instantiated may no
  1992     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1993     This is consistent with the instantiation attribute "where".
  1994 
  1995 * Attributes "where" and "of":
  1996   - Now take type variables of instantiated theorem into account when reading
  1997     the instantiation string.  This fixes a bug that caused instantiated
  1998     theorems to have too special types in some circumstances.
  1999   - "where" permits explicit instantiations of type variables.
  2000 
  2001 * Calculation commands "moreover" and "also" no longer interfere with
  2002   current facts ("this"), admitting arbitrary combinations with "then"
  2003   and derived forms.
  2004 
  2005 * Locales:
  2006   - Goal statements involving the context element "includes" no longer
  2007     generate theorems with internal delta predicates (those ending on
  2008     "_axioms") in the premise.
  2009     Resolve particular premise with <locale>.intro to obtain old form.
  2010   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2011     specification and "includes" elements in goal statement.
  2012   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2013     [intro?] and [elim?] (respectively) by default.
  2014   - Experimental command for instantiation of locales in proof contexts:
  2015         instantiate <label>[<attrs>]: <loc>
  2016     Instantiates locale <loc> and adds all its theorems to the current context
  2017     taking into account their attributes.  Label and attrs are optional
  2018     modifiers, like in theorem declarations.  If present, names of
  2019     instantiated theorems are qualified with <label>, and the attributes
  2020     <attrs> are applied after any attributes these theorems might have already.
  2021       If the locale has assumptions, a chained fact of the form
  2022     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2023     are derived.  The command does not support old-style locales declared
  2024     with "locale (open)".
  2025       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2026 
  2027 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2028   (Isar) contexts.
  2029 
  2030 
  2031 *** HOL ***
  2032 
  2033 * Proof import: new image HOL4 contains the imported library from
  2034   the HOL4 system with about 2500 theorems. It is imported by
  2035   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2036   can be used like any other Isabelle image.  See
  2037   HOL/Import/HOL/README for more information.
  2038 
  2039 * Simplifier:
  2040   - Much improved handling of linear and partial orders.
  2041     Reasoners for linear and partial orders are set up for type classes
  2042     "linorder" and "order" respectively, and are added to the default simpset
  2043     as solvers.  This means that the simplifier can build transitivity chains
  2044     to solve goals from the assumptions.
  2045   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2046     of blast or auto after simplification become unnecessary because the goal
  2047     is solved by simplification already.
  2048 
  2049 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2050     all proved in axiomatic type classes for semirings, rings and fields.
  2051 
  2052 * Numerics:
  2053   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2054     now formalized using the Ring_and_Field theory mentioned above.
  2055   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2056     than before, because now they are set up once in a generic manner.
  2057   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2058     Look for the general versions in Ring_and_Field (and Power if they concern
  2059     exponentiation).
  2060 
  2061 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2062 
  2063 * Records:
  2064   - Record types are now by default printed with their type abbreviation
  2065     instead of the list of all field types. This can be configured via
  2066     the reference "print_record_type_abbr".
  2067   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2068     (not enabled by default).
  2069   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2070     EX x. x = sel r to True (not enabled by default).
  2071   - Tactic "record_split_simp_tac" to split and simplify records added.
  2072 
  2073 * 'specification' command added, allowing for definition by
  2074   specification.  There is also an 'ax_specification' command that
  2075   introduces the new constants axiomatically.
  2076 
  2077 * arith(_tac) is now able to generate counterexamples for reals as well.
  2078 
  2079 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2080 
  2081 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2082   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2083 
  2084 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2085   matrix theory to linear programming.
  2086 
  2087 * Unions and Intersections:
  2088   The latex output syntax of UN and INT has been changed
  2089   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2090   i.e. the index formulae has become a subscript.
  2091   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2092 
  2093 * Unions and Intersections over Intervals:
  2094   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2095   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2096   like in normal math, and corresponding versions for < and for intersection.
  2097 
  2098 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2099   lexicographic dictonary ordering has been added as "lexord".
  2100 
  2101 * ML: the legacy theory structures Int and List have been removed. They had
  2102   conflicted with ML Basis Library structures having the same names.
  2103 
  2104 * 'refute' command added to search for (finite) countermodels.  Only works
  2105   for a fragment of HOL.  The installation of an external SAT solver is
  2106   highly recommended.  See "HOL/Refute.thy" for details.
  2107 
  2108 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2109   formulae under an assignment of free variables to random values.
  2110   In contrast to 'refute', it can deal with inductive datatypes,
  2111   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2112   for examples.
  2113 
  2114 
  2115 *** HOLCF ***
  2116 
  2117 * Streams now come with concatenation and are part of the HOLCF image
  2118 
  2119 
  2120 
  2121 New in Isabelle2003 (May 2003)
  2122 ------------------------------
  2123 
  2124 *** General ***
  2125 
  2126 * Provers/simplifier:
  2127 
  2128   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2129     Assumptions are now subject to complete mutual simplification,
  2130     not just from left to right. The simplifier now preserves
  2131     the order of assumptions.
  2132 
  2133     Potential INCOMPATIBILITY:
  2134 
  2135     -- simp sometimes diverges where the old version did
  2136        not, e.g. invoking simp on the goal
  2137 
  2138         [| P (f x); y = x; f x = f y |] ==> Q
  2139 
  2140        now gives rise to the infinite reduction sequence
  2141 
  2142         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2143 
  2144        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2145        kind of problem.
  2146 
  2147     -- Tactics combining classical reasoner and simplification (such as auto)
  2148        are also affected by this change, because many of them rely on
  2149        simp. They may sometimes diverge as well or yield a different numbers
  2150        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2151        in case of problems. Sometimes subsequent calls to the classical
  2152        reasoner will fail because a preceeding call to the simplifier too
  2153        eagerly simplified the goal, e.g. deleted redundant premises.
  2154 
  2155   - The simplifier trace now shows the names of the applied rewrite rules
  2156 
  2157   - You can limit the number of recursive invocations of the simplifier
  2158     during conditional rewriting (where the simplifie tries to solve the
  2159     conditions before applying the rewrite rule):
  2160     ML "simp_depth_limit := n"
  2161     where n is an integer. Thus you can force termination where previously
  2162     the simplifier would diverge.
  2163 
  2164   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2165 
  2166   - No longer aborts on failed congruence proof.  Instead, the
  2167     congruence is ignored.
  2168 
  2169 * Pure: New generic framework for extracting programs from constructive
  2170   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2171   as HOL/Extraction for some case studies.
  2172 
  2173 * Pure: The main goal of the proof state is no longer shown by default, only
  2174 the subgoals. This behaviour is controlled by a new flag.
  2175    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2176 (ML: Proof.show_main_goal).
  2177 
  2178 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2179 rules whose conclusion matches subgoal 1:
  2180       PG menu: Isabelle/Isar -> Show me -> matching rules
  2181 The rules are ordered by how closely they match the subgoal.
  2182 In particular, rules that solve a subgoal outright are displayed first
  2183 (or rather last, the way they are printed).
  2184 (ML: ProofGeneral.print_intros())
  2185 
  2186 * Pure: New flag trace_unify_fail causes unification to print
  2187 diagnostic information (PG: in trace buffer) when it fails. This is
  2188 useful for figuring out why single step proofs like rule, erule or
  2189 assumption failed.
  2190 
  2191 * Pure: Locale specifications now produce predicate definitions
  2192 according to the body of text (covering assumptions modulo local
  2193 definitions); predicate "loc_axioms" covers newly introduced text,
  2194 while "loc" is cumulative wrt. all included locale expressions; the
  2195 latter view is presented only on export into the global theory
  2196 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2197 on the old view without predicates;
  2198 
  2199 * Pure: predefined locales "var" and "struct" are useful for sharing
  2200 parameters (as in CASL, for example); just specify something like
  2201 ``var x + var y + struct M'' as import;
  2202 
  2203 * Pure: improved thms_containing: proper indexing of facts instead of
  2204 raw theorems; check validity of results wrt. current name space;
  2205 include local facts of proof configuration (also covers active
  2206 locales), cover fixed variables in index; may use "_" in term
  2207 specification; an optional limit for the number of printed facts may
  2208 be given (the default is 40);
  2209 
  2210 * Pure: disallow duplicate fact bindings within new-style theory files
  2211 (batch-mode only);
  2212 
  2213 * Provers: improved induct method: assumptions introduced by case
  2214 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2215 the goal statement); "foo" still refers to all facts collectively;
  2216 
  2217 * Provers: the function blast.overloaded has been removed: all constants
  2218 are regarded as potentially overloaded, which improves robustness in exchange
  2219 for slight decrease in efficiency;
  2220 
  2221 * Provers/linorder: New generic prover for transitivity reasoning over
  2222 linear orders.  Note: this prover is not efficient!
  2223 
  2224 * Isar: preview of problems to finish 'show' now produce an error
  2225 rather than just a warning (in interactive mode);
  2226 
  2227 
  2228 *** HOL ***
  2229 
  2230 * arith(_tac)
  2231 
  2232  - Produces a counter example if it cannot prove a goal.
  2233    Note that the counter example may be spurious if the goal is not a formula
  2234    of quantifier-free linear arithmetic.
  2235    In ProofGeneral the counter example appears in the trace buffer.
  2236 
  2237  - Knows about div k and mod k where k is a numeral of type nat or int.
  2238 
  2239  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2240    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2241    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2242 
  2243 * simp's arithmetic capabilities have been enhanced a bit: it now
  2244 takes ~= in premises into account (by performing a case split);
  2245 
  2246 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2247 are distributed over a sum of terms;
  2248 
  2249 * New tactic "trans_tac" and method "trans" instantiate
  2250 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2251 "<=", "<" and "=").
  2252 
  2253 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2254 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2255 
  2256 * 'typedef' command has new option "open" to suppress the set
  2257 definition;
  2258 
  2259 * functions Min and Max on finite sets have been introduced (theory
  2260 Finite_Set);
  2261 
  2262 * attribute [symmetric] now works for relations as well; it turns
  2263 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2264 
  2265 * induct over a !!-quantified statement (say !!x1..xn):
  2266   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2267 
  2268 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2269 %x. None. Warning: empty_def now refers to the previously hidden definition
  2270 of the empty set.
  2271 
  2272 * Algebra: formalization of classical algebra.  Intended as base for
  2273 any algebraic development in Isabelle.  Currently covers group theory
  2274 (up to Sylow's theorem) and ring theory (Universal Property of
  2275 Univariate Polynomials).  Contributions welcome;
  2276 
  2277 * GroupTheory: deleted, since its material has been moved to Algebra;
  2278 
  2279 * Complex: new directory of the complex numbers with numeric constants,
  2280 nonstandard complex numbers, and some complex analysis, standard and
  2281 nonstandard (Jacques Fleuriot);
  2282 
  2283 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2284 
  2285 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2286 Fleuriot);
  2287 
  2288 * Real/HahnBanach: updated and adapted to locales;
  2289 
  2290 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2291 Gray and Kramer);
  2292 
  2293 * UNITY: added the Meier-Sanders theory of progress sets;
  2294 
  2295 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2296 as abstract algorithms, instantiated to the JVM;
  2297 
  2298 * Bali: Java source language formalization. Type system, operational
  2299 semantics, axiomatic semantics. Supported language features:
  2300 classes, interfaces, objects,virtual methods, static methods,
  2301 static/instance fields, arrays, access modifiers, definite
  2302 assignment, exceptions.
  2303 
  2304 
  2305 *** ZF ***
  2306 
  2307 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2308 universe, etc.);
  2309 
  2310 * Main ZF: virtually all theories converted to new-style format;
  2311 
  2312 
  2313 *** ML ***
  2314 
  2315 * Pure: Tactic.prove provides sane interface for internal proofs;
  2316 omits the infamous "standard" operation, so this is more appropriate
  2317 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2318 
  2319 * Pure: improved error reporting of simprocs;
  2320 
  2321 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2322 up simprocs;
  2323 
  2324 
  2325 *** Document preparation ***
  2326 
  2327 * uses \par instead of \\ for line breaks in theory text. This may
  2328 shift some page breaks in large documents. To get the old behaviour
  2329 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2330 
  2331 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2332 other packages
  2333 
  2334 * \<euro> now needs package babel/greek instead of marvosym (which
  2335 broke \Rightarrow)
  2336 
  2337 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2338 textcomp package)
  2339 
  2340 
  2341 
  2342 New in Isabelle2002 (March 2002)
  2343 --------------------------------
  2344 
  2345 *** Document preparation ***
  2346 
  2347 * greatly simplified document preparation setup, including more
  2348 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2349 instructive isatool mkdir; users should basically be able to get
  2350 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2351 users may run a separate document processing stage manually like this:
  2352 "isatool usedir -D output HOL Test && isatool document Test/output";
  2353 
  2354 * theory dependency graph may now be incorporated into documents;
  2355 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2356 with \includegraphics of LaTeX;
  2357 
  2358 * proper spacing of consecutive markup elements, especially text
  2359 blocks after section headings;
  2360 
  2361 * support bold style (for single symbols only), input syntax is like
  2362 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2363 
  2364 * \<bullet> is now output as bold \cdot by default, which looks much
  2365 better in printed text;
  2366 
  2367 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2368 note that these symbols are currently unavailable in Proof General /
  2369 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2370 
  2371 * isatool latex no longer depends on changed TEXINPUTS, instead
  2372 isatool document copies the Isabelle style files to the target
  2373 location;
  2374 
  2375 
  2376 *** Isar ***
  2377 
  2378 * Pure/Provers: improved proof by cases and induction;
  2379   - 'case' command admits impromptu naming of parameters (such as
  2380     "case (Suc n)");
  2381   - 'induct' method divinates rule instantiation from the inductive
  2382     claim; no longer requires excessive ?P bindings for proper
  2383     instantiation of cases;
  2384   - 'induct' method properly enumerates all possibilities of set/type
  2385     rules; as a consequence facts may be also passed through *type*
  2386     rules without further ado;
  2387   - 'induct' method now derives symbolic cases from the *rulified*
  2388     rule (before it used to rulify cases stemming from the internal
  2389     atomized version); this means that the context of a non-atomic
  2390     statement becomes is included in the hypothesis, avoiding the
  2391     slightly cumbersome show "PROP ?case" form;
  2392   - 'induct' may now use elim-style induction rules without chaining
  2393     facts, using ``missing'' premises from the goal state; this allows
  2394     rules stemming from inductive sets to be applied in unstructured
  2395     scripts, while still benefitting from proper handling of non-atomic
  2396     statements; NB: major inductive premises need to be put first, all
  2397     the rest of the goal is passed through the induction;
  2398   - 'induct' proper support for mutual induction involving non-atomic
  2399     rule statements (uses the new concept of simultaneous goals, see
  2400     below);
  2401   - append all possible rule selections, but only use the first
  2402     success (no backtracking);
  2403   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2404   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2405   - added 'print_induct_rules' (covered by help item in recent Proof
  2406     General versions);
  2407   - moved induct/cases attributes to Pure, methods to Provers;
  2408   - generic method setup instantiated for FOL and HOL;
  2409 
  2410 * Pure: support multiple simultaneous goal statements, for example
  2411 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2412 meta-level mechanism, this acts as if several individual goals had
  2413 been stated separately; in particular common proof methods need to be
  2414 repeated in order to cover all claims; note that a single elimination
  2415 step is *not* sufficient to establish the two conjunctions, so this
  2416 fails:
  2417 
  2418   assume "A & B" then have A and B ..   (*".." fails*)
  2419 
  2420 better use "obtain" in situations as above; alternative refer to
  2421 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2422 
  2423 * Pure: proper integration with ``locales''; unlike the original
  2424 version by Florian Kammller, Isar locales package high-level proof
  2425 contexts rather than raw logical ones (e.g. we admit to include
  2426 attributes everywhere); operations on locales include merge and
  2427 rename; support for implicit arguments (``structures''); simultaneous
  2428 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2429 some examples;
  2430 
  2431 * Pure: the following commands have been ``localized'', supporting a
  2432 target locale specification "(in name)": 'lemma', 'theorem',
  2433 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2434 stored both within the locale and at the theory level (exported and
  2435 qualified by the locale name);
  2436 
  2437 * Pure: theory goals may now be specified in ``long'' form, with
  2438 ad-hoc contexts consisting of arbitrary locale elements. for example
  2439 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2440 definitions may be given, too); the result is a meta-level rule with
  2441 the context elements being discharged in the obvious way;
  2442 
  2443 * Pure: new proof command 'using' allows to augment currently used
  2444 facts after a goal statement ('using' is syntactically analogous to
  2445 'apply', but acts on the goal's facts only); this allows chained facts
  2446 to be separated into parts given before and after a claim, as in
  2447 ``from a and b have C using d and e <proof>'';
  2448 
  2449 * Pure: renamed "antecedent" case to "rule_context";
  2450 
  2451 * Pure: new 'judgment' command records explicit information about the
  2452 object-logic embedding (used by several tools internally); no longer
  2453 use hard-wired "Trueprop";
  2454 
  2455 * Pure: added 'corollary' command;
  2456 
  2457 * Pure: fixed 'token_translation' command;
  2458 
  2459 * Pure: removed obsolete 'exported' attribute;
  2460 
  2461 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2462 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2463 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2464 
  2465 * Pure: method 'atomize' presents local goal premises as object-level
  2466 statements (atomic meta-level propositions); setup controlled via
  2467 rewrite rules declarations of 'atomize' attribute; example
  2468 application: 'induct' method with proper rule statements in improper
  2469 proof *scripts*;
  2470 
  2471 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2472 now consider the syntactic context of assumptions, giving a better
  2473 chance to get type-inference of the arguments right (this is
  2474 especially important for locales);
  2475 
  2476 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2477 mode;
  2478 
  2479 * Pure/obtain: the formal conclusion "thesis", being marked as
  2480 ``internal'', may no longer be reference directly in the text;
  2481 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2482 situations;
  2483 
  2484 * Pure: generic 'sym' attribute which declares a rule both as pure
  2485 'elim?' and for the 'symmetric' operation;
  2486 
  2487 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2488 text; the fixed correlation with particular command syntax has been
  2489 discontinued;
  2490 
  2491 * Pure: new method 'rules' is particularly well-suited for proof
  2492 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2493 but often produces more compact proof terms with less detours;
  2494 
  2495 * Pure/Provers/classical: simplified integration with pure rule
  2496 attributes and methods; the classical "intro?/elim?/dest?"
  2497 declarations coincide with the pure ones; the "rule" method no longer
  2498 includes classically swapped intros; "intro" and "elim" methods no
  2499 longer pick rules from the context; also got rid of ML declarations
  2500 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2501 INCOMPATIBILITY;
  2502 
  2503 * Provers/classical: attribute 'swapped' produces classical inversions
  2504 of introduction rules;
  2505 
  2506 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2507 rules instead of full simplifier context; 'iff' attribute handles
  2508 conditional rules;
  2509 
  2510 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2511 
  2512 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2513 "(permissive)" option to recover old behavior;
  2514 
  2515 * HOL: 'inductive' no longer features separate (collective) attributes
  2516 for 'intros' (was found too confusing);
  2517 
  2518 * HOL: properly declared induction rules less_induct and
  2519 wf_induct_rule;
  2520 
  2521 
  2522 *** HOL ***
  2523 
  2524 * HOL: moved over to sane numeral syntax; the new policy is as
  2525 follows:
  2526 
  2527   - 0 and 1 are polymorphic constants, which are defined on any
  2528   numeric type (nat, int, real etc.);
  2529 
  2530   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2531   binary representation internally;
  2532 
  2533   - type nat has special constructor Suc, and generally prefers Suc 0
  2534   over 1::nat and Suc (Suc 0) over 2::nat;
  2535 
  2536 This change may cause significant problems of INCOMPATIBILITY; here
  2537 are some hints on converting existing sources:
  2538 
  2539   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2540   entities, so expressions involving "-" (unary or binary minus) need
  2541   to be spaced properly;
  2542 
  2543   - existing occurrences of "1" may need to be constraint "1::nat" or
  2544   even replaced by Suc 0; similar for old "2";
  2545 
  2546   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2547 
  2548   - remove all special provisions on numerals in proofs;
  2549 
  2550 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2551 representation (depends on bin_arith_simps in the default context);
  2552 
  2553 * HOL: symbolic syntax for x^2 (numeral 2);
  2554 
  2555 * HOL: the class of all HOL types is now called "type" rather than
  2556 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2557 in axclass/classes, instance/arities, and (usually rare) occurrences
  2558 in typings (of consts etc.); internally the class is called
  2559 "HOL.type", ML programs should refer to HOLogic.typeS;
  2560 
  2561 * HOL/record package improvements:
  2562   - new derived operations "fields" to build a partial record section,
  2563     "extend" to promote a fixed record to a record scheme, and
  2564     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2565     declared as simp by default;
  2566   - shared operations ("more", "fields", etc.) now need to be always
  2567     qualified) --- potential INCOMPATIBILITY;
  2568   - removed "make_scheme" operations (use "make" with "extend") --
  2569     INCOMPATIBILITY;
  2570   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2571   - provides cases/induct rules for use with corresponding Isar
  2572     methods (for concrete records, record schemes, concrete more
  2573     parts, and schematic more parts -- in that order);
  2574   - internal definitions directly based on a light-weight abstract
  2575     theory of product types over typedef rather than datatype;
  2576 
  2577 * HOL: generic code generator for generating executable ML code from
  2578 specifications; specific support for HOL constructs such as inductive
  2579 datatypes and sets, as well as recursive functions; can be invoked
  2580 via 'generate_code' theory section;
  2581 
  2582 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2583 
  2584 * HOL: consolidated and renamed several theories.  In particular:
  2585         Ord.thy has been absorbed into HOL.thy
  2586         String.thy has been absorbed into List.thy
  2587 
  2588 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2589 (beware of argument permutation!);
  2590 
  2591 * HOL: linorder_less_split superseded by linorder_cases;
  2592 
  2593 * HOL/List: "nodups" renamed to "distinct";
  2594 
  2595 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2596 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2597   - Ex_def has changed, now need to use some_eq_ex
  2598 
  2599 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2600 in this (rare) case use:
  2601 
  2602   delSWrapper "split_all_tac"
  2603   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2604 
  2605 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2606 MAY FAIL;
  2607 
  2608 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2609 Isabelle's type classes, ^ on functions and relations has too general
  2610 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2611 necessary to attach explicit type constraints;
  2612 
  2613 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2614 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2615 renamed accordingly (eg "compI" -> "rel_compI").
  2616 
  2617 * HOL: syntax translations now work properly with numerals and records
  2618 expressions;
  2619 
  2620 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2621 of "lam" -- INCOMPATIBILITY;
  2622 
  2623 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2624 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2625 renamed "Product_Type.unit";
  2626 
  2627 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2628 
  2629 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2630 the "cases" method);
  2631 
  2632 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2633 Florian Kammller);
  2634 
  2635 * HOL/IMP: updated and converted to new-style theory format; several
  2636 parts turned into readable document, with proper Isar proof texts and
  2637 some explanations (by Gerwin Klein);
  2638 
  2639 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2640 
  2641 * HOL-Hyperreal is now a logic image;
  2642 
  2643 
  2644 *** HOLCF ***
  2645 
  2646 * Isar: consts/constdefs supports mixfix syntax for continuous
  2647 operations;
  2648 
  2649 * Isar: domain package adapted to new-style theory format, e.g. see
  2650 HOLCF/ex/Dnat.thy;
  2651 
  2652 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2653 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2654 lift.induct_tac, always use UU instead of Undef;
  2655 
  2656 * HOLCF/IMP: updated and converted to new-style theory;
  2657 
  2658 
  2659 *** ZF ***
  2660 
  2661 * Isar: proper integration of logic-specific tools and packages,
  2662 including theory commands '(co)inductive', '(co)datatype',
  2663 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2664 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2665 
  2666 * theory Main no longer includes AC; for the Axiom of Choice, base
  2667 your theory on Main_ZFC;
  2668 
  2669 * the integer library now covers quotients and remainders, with many
  2670 laws relating division to addition, multiplication, etc.;
  2671 
  2672 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2673 typeless version of the formalism;
  2674 
  2675 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2676 format;
  2677 
  2678 * ZF/Induct: new directory for examples of inductive definitions,
  2679 including theory Multiset for multiset orderings; converted to
  2680 new-style theory format;
  2681 
  2682 * ZF: many new theorems about lists, ordinals, etc.;
  2683 
  2684 
  2685 *** General ***
  2686 
  2687 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2688 variable proof controls level of detail: 0 = no proofs (only oracle
  2689 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2690 also ref manual for further ML interfaces;
  2691 
  2692 * Pure/axclass: removed obsolete ML interface
  2693 goal_subclass/goal_arity;
  2694 
  2695 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2696 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2697 separate tokens, so expressions involving minus need to be spaced
  2698 properly;
  2699 
  2700 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2701 rather than "infixl" or "infixr";
  2702 
  2703 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2704 sort constraint specifications in type inference; e.g. "x::_::foo"
  2705 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2706 type variable);
  2707 
  2708 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2709 control output of nested => (types); the default behavior is
  2710 "type_brackets";
  2711 
  2712 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2713 tokens into AST constants;
  2714 
  2715 * Pure/syntax: prefer later declarations of translations and print
  2716 translation functions; potential INCOMPATIBILITY: need to reverse
  2717 multiple declarations for same syntax element constant;
  2718 
  2719 * Pure/show_hyps reset by default (in accordance to existing Isar
  2720 practice);
  2721 
  2722 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2723 addSafter;
  2724 
  2725 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2726 as well;
  2727 
  2728 * system: tested support for MacOS X; should be able to get Isabelle +
  2729 Proof General to work in a plain Terminal after installing Poly/ML
  2730 (e.g. from the Isabelle distribution area) and GNU bash alone
  2731 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2732 support requires further installations, e.g. from
  2733 http://fink.sourceforge.net/);
  2734 
  2735 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2736 
  2737 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2738 of 40 MB), cf. ML_OPTIONS;
  2739 
  2740 * system: Proof General keywords specification is now part of the
  2741 Isabelle distribution (see etc/isar-keywords.el);
  2742 
  2743 * system: support for persistent Proof General sessions (refrain from
  2744 outdating all loaded theories on startup); user may create writable
  2745 logic images like this: ``isabelle -q HOL Test'';
  2746 
  2747 * system: smart selection of Isabelle process versus Isabelle
  2748 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2749 run both "isabelle" and "Isabelle" even if file names are badly
  2750 damaged (executable inspects the case of the first letter of its own
  2751 name); added separate "isabelle-process" and "isabelle-interface";
  2752 
  2753 * system: refrain from any attempt at filtering input streams; no
  2754 longer support ``8bit'' encoding of old isabelle font, instead proper
  2755 iso-latin characters may now be used; the related isatools
  2756 "symbolinput" and "nonascii" have disappeared as well;
  2757 
  2758 * system: removed old "xterm" interface (the print modes "xterm" and
  2759 "xterm_color" are still available for direct use in a suitable
  2760 terminal);
  2761 
  2762 
  2763 
  2764 New in Isabelle99-2 (February 2001)
  2765 -----------------------------------
  2766 
  2767 *** Overview of INCOMPATIBILITIES ***
  2768 
  2769 * HOL: please note that theories in the Library and elsewhere often use the
  2770 new-style (Isar) format; to refer to their theorems in an ML script you must
  2771 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2772 
  2773 * HOL: inductive package no longer splits induction rule aggressively,
  2774 but only as far as specified by the introductions given; the old
  2775 format may be recovered via ML function complete_split_rule or attribute
  2776 'split_rule (complete)';
  2777 
  2778 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2779 gfp_Tarski to gfp_unfold;
  2780 
  2781 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2782 
  2783 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2784 relation); infix "^^" has been renamed "``"; infix "``" has been
  2785 renamed "`"; "univalent" has been renamed "single_valued";
  2786 
  2787 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2788 operation;
  2789 
  2790 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2791 
  2792 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2793 
  2794 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2795 consequence, it is no longer monotonic wrt. the local goal context
  2796 (which is now passed through the inductive cases);
  2797 
  2798 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2799 \<gg> to \<ggreater>;
  2800 
  2801 
  2802 *** Document preparation ***
  2803 
  2804 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2805 available: are "it" for near math-mode best-style output, "sl" for
  2806 slanted text style, and "tt" for plain type-writer; if no
  2807 \isabellestyle command is given, output is according to slanted
  2808 type-writer);
  2809 
  2810 * support sub/super scripts (for single symbols only), input syntax is
  2811 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2812 
  2813 * some more standard symbols; see Appendix A of the system manual for
  2814 the complete list of symbols defined in isabellesym.sty;
  2815 
  2816 * improved isabelle style files; more abstract symbol implementation
  2817 (should now use \isamath{...} and \isatext{...} in custom symbol
  2818 definitions);
  2819 
  2820 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2821 state; Note that presentation of goal states does not conform to
  2822 actual human-readable proof documents.  Please do not include goal
  2823 states into document output unless you really know what you are doing!
  2824 
  2825 * proper indentation of antiquoted output with proportional LaTeX
  2826 fonts;
  2827 
  2828 * no_document ML operator temporarily disables LaTeX document
  2829 generation;
  2830 
  2831 * isatool unsymbolize tunes sources for plain ASCII communication;
  2832 
  2833 
  2834 *** Isar ***
  2835 
  2836 * Pure: Isar now suffers initial goal statements to contain unbound
  2837 schematic variables (this does not conform to actual readable proof
  2838 documents, due to unpredictable outcome and non-compositional proof
  2839 checking); users who know what they are doing may use schematic goals
  2840 for Prolog-style synthesis of proven results;
  2841 
  2842 * Pure: assumption method (an implicit finishing) now handles actual
  2843 rules as well;
  2844 
  2845 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2846 initial goal, declare "that" only as Pure intro (only for single
  2847 steps); the "that" rule assumption may now be involved in implicit
  2848 finishing, thus ".." becomes a feasible for trivial obtains;
  2849 
  2850 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2851 instance proofs may be performed by "..";
  2852 
  2853 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2854 statements as well;
  2855 
  2856 * Pure: more robust selection of calculational rules;
  2857 
  2858 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2859 rule (as well as the assumption rule);
  2860 
  2861 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2862 lemmas, using the graph browser tool;
  2863 
  2864 * Pure: predict failure of "show" in interactive mode;
  2865 
  2866 * Pure: 'thms_containing' now takes actual terms as arguments;
  2867 
  2868 * HOL: improved method 'induct' --- now handles non-atomic goals
  2869 (potential INCOMPATIBILITY); tuned error handling;
  2870 
  2871 * HOL: cases and induct rules now provide explicit hints about the
  2872 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2873 any remaining facts are inserted into the goal verbatim;
  2874 
  2875 * HOL: local contexts (aka cases) may now contain term bindings as
  2876 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2877 the result to be shown in each case;
  2878 
  2879 * HOL: added 'recdef_tc' command;
  2880 
  2881 * isatool convert assists in eliminating legacy ML scripts;
  2882 
  2883 
  2884 *** HOL ***
  2885 
  2886 * HOL/Library: a collection of generic theories to be used together
  2887 with main HOL; the theory loader path already includes this directory
  2888 by default; the following existing theories have been moved here:
  2889 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2890 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2891 
  2892 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2893 modelling and verification task performed in Isabelle/HOL +
  2894 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2895 
  2896 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2897 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2898 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2899 'domain', this makes the theory consistent with mathematical
  2900 literature;
  2901 
  2902 * HOL basics: added overloaded operations "inverse" and "divide"
  2903 (infix "/"), syntax for generic "abs" operation, generic summation
  2904 operator \<Sum>;
  2905 
  2906 * HOL/typedef: simplified package, provide more useful rules (see also
  2907 HOL/subset.thy);
  2908 
  2909 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2910 now expressed as a proper nested rule (old-style tactic scripts may
  2911 require atomize_strip_tac to cope with non-atomic premises);
  2912 
  2913 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2914 to "split_conv" (old name still available for compatibility);
  2915 
  2916 * HOL: improved concrete syntax for strings (e.g. allows translation
  2917 rules with string literals);
  2918 
  2919 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2920  and Fleuriot's mechanization of analysis, including the transcendental
  2921  functions for the reals;
  2922 
  2923 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2924 
  2925 
  2926 *** CTT ***
  2927 
  2928 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2929 "lam" is displayed as TWO lambda-symbols
  2930 
  2931 * CTT: theory Main now available, containing everything (that is, Bool
  2932 and Arith);
  2933 
  2934 
  2935 *** General ***
  2936 
  2937 * Pure: the Simplifier has been implemented properly as a derived rule
  2938 outside of the actual kernel (at last!); the overall performance
  2939 penalty in practical applications is about 50%, while reliability of
  2940 the Isabelle inference kernel has been greatly improved;
  2941 
  2942 * print modes "brackets" and "no_brackets" control output of nested =>
  2943 (types) and ==> (props); the default behaviour is "brackets";
  2944 
  2945 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2946 as assumptions as well;
  2947 
  2948 * system: support Poly/ML 4.0;
  2949 
  2950 * system: isatool install handles KDE version 1 or 2;
  2951 
  2952 
  2953 
  2954 New in Isabelle99-1 (October 2000)
  2955 ----------------------------------
  2956 
  2957 *** Overview of INCOMPATIBILITIES ***
  2958 
  2959 * HOL: simplification of natural numbers is much changed; to partly
  2960 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2961 issue the following ML commands:
  2962 
  2963   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2964   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2965 
  2966 * HOL: simplification no longer dives into case-expressions; this is
  2967 controlled by "t.weak_case_cong" for each datatype t;
  2968 
  2969 * HOL: nat_less_induct renamed to less_induct;
  2970 
  2971 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2972 fixsome to patch .thy and .ML sources automatically;
  2973 
  2974   select_equality  -> some_equality
  2975   select_eq_Ex     -> some_eq_ex
  2976   selectI2EX       -> someI2_ex
  2977   selectI2         -> someI2
  2978   selectI          -> someI
  2979   select1_equality -> some1_equality
  2980   Eps_sym_eq       -> some_sym_eq_trivial
  2981   Eps_eq           -> some_eq_trivial
  2982 
  2983 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2984 
  2985 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2986 instead);
  2987 
  2988 * HOL: the recursion equations generated by 'recdef' are now called
  2989 f.simps instead of f.rules;
  2990 
  2991 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2992 
  2993 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2994 sometimes be needed;
  2995 
  2996 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2997 
  2998 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2999 
  3000 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3001 product is now "<*>" instead of "Times"; the lexicographic product is
  3002 now "<*lex*>" instead of "**";
  3003 
  3004 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3005 of main HOL, but was unused); better use HOL's datatype package;
  3006 
  3007 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3008 the old syntax may be recovered as follows:
  3009 
  3010   syntax (symbols)
  3011     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3012       (infixl "\\<oplus>" 100)
  3013 
  3014 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3015 
  3016 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3017 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3018 internally;
  3019 
  3020 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3021 changed from A/r to A//r;
  3022 
  3023 * ZF: new treatment of arithmetic (nat & int) may break some old
  3024 proofs;
  3025 
  3026 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3027 rulify -> rule_format, elimify -> elim_format, ...);
  3028 
  3029 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3030 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3031 should have to change intro!! to intro? only); replaced "delrule" by
  3032 "rule del";
  3033 
  3034 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3035 
  3036 * Provers: strengthened force_tac by using new first_best_tac;
  3037 
  3038 * LaTeX document preparation: several changes of isabelle.sty (see
  3039 lib/texinputs);
  3040 
  3041 
  3042 *** Document preparation ***
  3043 
  3044 * formal comments (text blocks etc.) in new-style theories may now
  3045 contain antiquotations of thm/prop/term/typ/text to be presented
  3046 according to latex print mode; concrete syntax is like this:
  3047 @{term[show_types] "f(x) = a + x"};
  3048 
  3049 * isatool mkdir provides easy setup of Isabelle session directories,
  3050 including proper document sources;
  3051 
  3052 * generated LaTeX sources are now deleted after successful run
  3053 (isatool document -c); may retain a copy somewhere else via -D option
  3054 of isatool usedir;
  3055 
  3056 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3057 style files, achieving self-contained LaTeX sources and simplifying
  3058 LaTeX debugging;
  3059 
  3060 * old-style theories now produce (crude) LaTeX output as well;
  3061 
  3062 * browser info session directories are now self-contained (may be put
  3063 on WWW server seperately); improved graphs of nested sessions; removed
  3064 graph for 'all sessions';
  3065 
  3066 * several improvements in isabelle style files; \isabellestyle{it}
  3067 produces fake math mode output; \isamarkupheader is now \section by
  3068 default; see lib/texinputs/isabelle.sty etc.;
  3069 
  3070 
  3071 *** Isar ***
  3072 
  3073 * Isar/Pure: local results and corresponding term bindings are now
  3074 subject to Hindley-Milner polymorphism (similar to ML); this
  3075 accommodates incremental type-inference very nicely;
  3076 
  3077 * Isar/Pure: new derived language element 'obtain' supports
  3078 generalized existence reasoning;
  3079 
  3080 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3081 support accumulation of results, without applying any rules yet;
  3082 useful to collect intermediate results without explicit name
  3083 references, and for use with transitivity rules with more than 2
  3084 premises;
  3085 
  3086 * Isar/Pure: scalable support for case-analysis type proofs: new
  3087 'case' language element refers to local contexts symbolically, as
  3088 produced by certain proof methods; internally, case names are attached
  3089 to theorems as "tags";
  3090 
  3091 * Isar/Pure: theory command 'hide' removes declarations from
  3092 class/type/const name spaces;
  3093 
  3094 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3095 indicate potential overloading;
  3096 
  3097 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3098 
  3099 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3100 "{a,b,c}" instead of {a,b,c};
  3101 
  3102 * Isar/Pure now provides its own version of intro/elim/dest
  3103 attributes; useful for building new logics, but beware of confusion
  3104 with the version in Provers/classical;
  3105 
  3106 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3107 case name 'antecedent';
  3108 
  3109 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3110 to the current context is now done automatically);
  3111 
  3112 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3113 for definining proof methods in ML;
  3114 
  3115 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3116 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3117 most cases, one should have to change intro!! to intro? only);
  3118 replaced "delrule" by "rule del";
  3119 
  3120 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3121 'symmetric' attribute (the latter supercedes [RS sym]);
  3122 
  3123 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3124 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3125 well (including splits);
  3126 
  3127 * Isar/Provers: Simplifier and Classical methods now support all kind
  3128 of modifiers used in the past, including 'cong', 'iff', etc.
  3129 
  3130 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3131 of Simplifier and Classical reasoner);
  3132 
  3133 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3134 now support named cases; major packages (inductive, datatype, primrec,
  3135 recdef) support case names and properly name parameters;
  3136 
  3137 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3138 monotonicity conditions are extracted to be proven at end of
  3139 calculations;
  3140 
  3141 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3142 method anyway;
  3143 
  3144 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3145 split_if split_if_asm; datatype package provides theorems foo.splits =
  3146 foo.split foo.split_asm for each datatype;
  3147 
  3148 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3149 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3150 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3151 use "(cases (simplified))" method in proper proof texts);
  3152 
  3153 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3154 
  3155 * Isar: names of theorems etc. may be natural numbers as well;
  3156 
  3157 * Isar: 'pr' command: optional arguments for goals_limit and
  3158 ProofContext.prems_limit; no longer prints theory contexts, but only
  3159 proof states;
  3160 
  3161 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3162 additional print modes to be specified; e.g. "pr(latex)" will print
  3163 proof state according to the Isabelle LaTeX style;
  3164 
  3165 * Isar: improved support for emulating tactic scripts, including proof
  3166 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3167 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3168 (for HOL datatypes);
  3169 
  3170 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3171 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3172 'proof method scripts' have to be in depth-first order;
  3173 
  3174 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3175 
  3176 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3177 should instead use individual commands for printing items
  3178 (print_commands, print_methods etc.);
  3179 
  3180 * Isar: added 'nothing' --- the empty list of theorems;
  3181 
  3182 
  3183 *** HOL ***
  3184 
  3185 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3186 corresponding virtual machine and a specification of its bytecode
  3187 verifier and a lightweight bytecode verifier, including proofs of
  3188 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3189 Cornelia Pusch (see also the homepage of project Bali at
  3190 http://isabelle.in.tum.de/Bali/);
  3191 
  3192 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3193 Clemens Ballarin;
  3194 
  3195 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3196 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3197 Rasmussen;
  3198 
  3199 * HOL/Lattice: fundamental concepts of lattice theory and order
  3200 structures, including duals, properties of bounds versus algebraic
  3201 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3202 Theorem for complete lattices etc.; may also serve as a demonstration
  3203 for abstract algebraic reasoning using axiomatic type classes, and
  3204 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3205 
  3206 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3207 von Oheimb;
  3208 
  3209 * HOL/IMPP: extension of IMP with local variables and mutually
  3210 recursive procedures, by David von Oheimb;
  3211 
  3212 * HOL/Lambda: converted into new-style theory and document;
  3213 
  3214 * HOL/ex/Multiquote: example of multiple nested quotations and
  3215 anti-quotations -- basically a generalized version of de-Bruijn
  3216 representation; very useful in avoiding lifting of operations;
  3217 
  3218 * HOL/record: added general record equality rule to simpset; fixed
  3219 select-update simplification procedure to handle extended records as
  3220 well; admit "r" as field name;
  3221 
  3222 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3223 other numeric types and also as the identity of groups, rings, etc.;
  3224 
  3225 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3226 Types nat and int belong to this axclass;
  3227 
  3228 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3229    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3230    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3231   two terms #m*u and #n*u are replaced by #(m+n)*u
  3232     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3233   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3234     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3235 
  3236 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3237 powerful prover for predicate logic but knows nothing of clasets; see
  3238 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3239 
  3240 * HOL: new version of "case_tac" subsumes both boolean case split and
  3241 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3242 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3243 
  3244 * HOL: simplification no longer dives into case-expressions: only the
  3245 selector expression is simplified, but not the remaining arms; to
  3246 enable full simplification of case-expressions for datatype t, you may
  3247 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3248 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3249 
  3250 * HOL/recdef: the recursion equations generated by 'recdef' for
  3251 function 'f' are now called f.simps instead of f.rules; if all
  3252 termination conditions are proved automatically, these simplification
  3253 rules are added to the simpset, as in primrec; rules may be named
  3254 individually as well, resulting in a separate list of theorems for
  3255 each equation;
  3256 
  3257 * HOL/While is a new theory that provides a while-combinator. It
  3258 permits the definition of tail-recursive functions without the
  3259 provision of a termination measure. The latter is necessary once the
  3260 invariant proof rule for while is applied.
  3261 
  3262 * HOL: new (overloaded) notation for the set of elements below/above
  3263 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3264 
  3265 * HOL: theorems impI, allI, ballI bound as "strip";
  3266 
  3267 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3268 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3269 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3270 
  3271 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3272 
  3273 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3274 main HOL, but was unused);
  3275 
  3276 * HOL: fewer consts declared as global (e.g. have to refer to
  3277 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3278 
  3279 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3280 in case of overlap with user translations (e.g. judgements over
  3281 tuples); (note that the underlying logical represenation is still
  3282 bogus);
  3283 
  3284 
  3285 *** ZF ***
  3286 
  3287 * ZF: simplification automatically cancels common terms in arithmetic
  3288 expressions over nat and int;
  3289 
  3290 * ZF: new treatment of nat to minimize type-checking: all operators
  3291 coerce their operands to a natural number using the function natify,
  3292 making the algebraic laws unconditional;
  3293 
  3294 * ZF: as above, for int: operators coerce their operands to an integer
  3295 using the function intify;
  3296 
  3297 * ZF: the integer library now contains many of the usual laws for the
  3298 orderings, including $<=, and monotonicity laws for $+ and $*;
  3299 
  3300 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3301 simplification;
  3302 
  3303 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3304 to the simplifier and classical reasoner simultaneously;
  3305 
  3306 
  3307 *** General ***
  3308 
  3309 * Provers: blast_tac now handles actual object-logic rules as
  3310 assumptions; note that auto_tac uses blast_tac internally as well;
  3311 
  3312 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3313 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3314 
  3315 * Provers: delrules now handles destruct rules as well (no longer need
  3316 explicit make_elim);
  3317 
  3318 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3319   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3320 use instead the strong form,
  3321   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3322 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3323 from destruct-rules;
  3324 
  3325 * Provers: Simplifier.easy_setup provides a fast path to basic
  3326 Simplifier setup for new object-logics;
  3327 
  3328 * Pure: AST translation rules no longer require constant head on LHS;
  3329 
  3330 * Pure: improved name spaces: ambiguous output is qualified; support
  3331 for hiding of names;
  3332 
  3333 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3334 XSYMBOL_HOME; no longer need to do manual configuration in most
  3335 situations;
  3336 
  3337 * system: compression of ML heaps images may now be controlled via -c
  3338 option of isabelle and isatool usedir (currently only observed by
  3339 Poly/ML);
  3340 
  3341 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3342 useful for remote X11);
  3343 
  3344 * system: provide TAGS file for Isabelle sources;
  3345 
  3346 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3347 order;
  3348 
  3349 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3350 timing flag supersedes proof_timing and Toplevel.trace;
  3351 
  3352 * ML: new combinators |>> and |>>> for incremental transformations
  3353 with secondary results (e.g. certain theory extensions):
  3354 
  3355 * ML: PureThy.add_defs gets additional argument to indicate potential
  3356 overloading (usually false);
  3357 
  3358 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3359 results;
  3360 
  3361 
  3362 
  3363 New in Isabelle99 (October 1999)
  3364 --------------------------------
  3365 
  3366 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3367 
  3368 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3369 are no longer simplified.  (This allows the simplifier to unfold recursive
  3370 functional programs.)  To restore the old behaviour, declare
  3371 
  3372     Delcongs [if_weak_cong];
  3373 
  3374 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3375 complement;
  3376 
  3377 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3378 
  3379 * HOL/datatype: mutual_induct_tac no longer exists --
  3380   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3381 
  3382 * HOL/typedef: fixed type inference for representing set; type
  3383 arguments now have to occur explicitly on the rhs as type constraints;
  3384 
  3385 * ZF: The con_defs part of an inductive definition may no longer refer
  3386 to constants declared in the same theory;
  3387 
  3388 * HOL, ZF: the function mk_cases, generated by the inductive
  3389 definition package, has lost an argument.  To simplify its result, it
  3390 uses the default simpset instead of a supplied list of theorems.
  3391 
  3392 * HOL/List: the constructors of type list are now Nil and Cons;
  3393 
  3394 * Simplifier: the type of the infix ML functions
  3395         setSSolver addSSolver setSolver addSolver
  3396 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3397 for packaging solvers. A solver is created via
  3398         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3399 where the string argument is only a comment.
  3400 
  3401 
  3402 *** Proof tools ***
  3403 
  3404 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3405 decision procedure for linear arithmetic. Currently it is used for
  3406 types `nat', `int', and `real' in HOL (see below); it can, should and
  3407 will be instantiated for other types and logics as well.
  3408 
  3409 * The simplifier now accepts rewrite rules with flexible heads, eg
  3410      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3411   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3412   matching.
  3413 
  3414 
  3415 *** General ***
  3416 
  3417 * New Isabelle/Isar subsystem provides an alternative to traditional
  3418 tactical theorem proving; together with the ProofGeneral/isar user
  3419 interface it offers an interactive environment for developing human
  3420 readable proof documents (Isar == Intelligible semi-automated
  3421 reasoning); for further information see isatool doc isar-ref,
  3422 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3423 
  3424 * improved and simplified presentation of theories: better HTML markup
  3425 (including colors), graph views in several sizes; isatool usedir now
  3426 provides a proper interface for user theories (via -P option); actual
  3427 document preparation based on (PDF)LaTeX is available as well (for
  3428 new-style theories only); see isatool doc system for more information;
  3429 
  3430 * native support for Proof General, both for classic Isabelle and
  3431 Isabelle/Isar;
  3432 
  3433 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3434 using the graph browser tool;
  3435 
  3436 * Isabelle manuals now also available as PDF;
  3437 
  3438 * theory loader rewritten from scratch (may not be fully
  3439 bug-compatible); old loadpath variable has been replaced by show_path,
  3440 add_path, del_path, reset_path functions; new operations such as
  3441 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3442 isatool doc ref);
  3443 
  3444 * improved isatool install: option -k creates KDE application icon,
  3445 option -p DIR installs standalone binaries;
  3446 
  3447 * added ML_PLATFORM setting (useful for cross-platform installations);
  3448 more robust handling of platform specific ML images for SML/NJ;
  3449 
  3450 * the settings environment is now statically scoped, i.e. it is never
  3451 created again in sub-processes invoked from isabelle, isatool, or
  3452 Isabelle;
  3453 
  3454 * path element specification '~~' refers to '$ISABELLE_HOME';
  3455 
  3456 * in locales, the "assumes" and "defines" parts may be omitted if
  3457 empty;
  3458 
  3459 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3460 long arrows);
  3461 
  3462 * new print_mode "HTML";
  3463 
  3464 * new flag show_tags controls display of tags of theorems (which are
  3465 basically just comments that may be attached by some tools);
  3466 
  3467 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3468 mode and goal output format:
  3469 
  3470 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3471 244c244
  3472 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3473 ---
  3474 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3475 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3476 181c181
  3477 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3478 ---
  3479 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3480 
  3481 * function bind_thms stores lists of theorems (cf. bind_thm);
  3482 
  3483 * new shorthand tactics ftac, eatac, datac, fatac;
  3484 
  3485 * qed (and friends) now accept "" as result name; in that case the
  3486 theorem is not stored, but proper checks and presentation of the
  3487 result still apply;
  3488 
  3489 * theorem database now also indexes constants "Trueprop", "all",
  3490 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3491 
  3492 
  3493 *** HOL ***
  3494 
  3495 ** HOL arithmetic **
  3496 
  3497 * There are now decision procedures for linear arithmetic over nat and
  3498 int:
  3499 
  3500 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3501 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3502 are treated as atomic; subformulae not involving type `nat' or `int'
  3503 are ignored; quantified subformulae are ignored unless they are
  3504 positive universal or negative existential. The tactic has to be
  3505 invoked by hand and can be a little bit slow. In particular, the
  3506 running time is exponential in the number of occurrences of `min' and
  3507 `max', and `-' on `nat'.
  3508 
  3509 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3510 (negated) (in)equalities among the premises and the conclusion into
  3511 account (i.e. no compound formulae) and does not know about `min' and
  3512 `max', and `-' on `nat'. It is fast and is used automatically by the
  3513 simplifier.
  3514 
  3515 NB: At the moment, these decision procedures do not cope with mixed
  3516 nat/int formulae where the two parts interact, such as `m < n ==>
  3517 int(m) < int(n)'.
  3518 
  3519 * HOL/Numeral provides a generic theory of numerals (encoded
  3520 efficiently as bit strings); setup for types nat/int/real is in place;
  3521 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3522 int, existing theories and proof scripts may require a few additional
  3523 type constraints;
  3524 
  3525 * integer division and remainder can now be performed on constant
  3526 arguments;
  3527 
  3528 * many properties of integer multiplication, division and remainder
  3529 are now available;
  3530 
  3531 * An interface to the Stanford Validity Checker (SVC) is available through the
  3532 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3533 are proved automatically.  SVC must be installed separately, and its results
  3534 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3535 invocation of the underlying oracle).  For SVC see
  3536   http://verify.stanford.edu/SVC
  3537 
  3538 * IsaMakefile: the HOL-Real target now builds an actual image;
  3539 
  3540 
  3541 ** HOL misc **
  3542 
  3543 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3544 (in Isabelle/Isar) -- by Gertrud Bauer;
  3545 
  3546 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3547 analysis for assembly languages with subtypes;
  3548 
  3549 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3550 -- avoids syntactic ambiguities and treats state, transition, and
  3551 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3552 changed syntax and (many) tactics;
  3553 
  3554 * HOL/inductive: Now also handles more general introduction rules such
  3555   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3556   theorems are now maintained within the theory (maintained via the
  3557   "mono" attribute);
  3558 
  3559 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3560   (using function types) such as
  3561 
  3562   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3563 
  3564 * HOL/record: record_simproc (part of the default simpset) takes care
  3565 of selectors applied to updated records; record_split_tac is no longer
  3566 part of the default claset; update_defs may now be removed from the
  3567 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3568 
  3569   claset_ref () := claset() addSWrapper record_split_wrapper;
  3570   Delsimprocs [record_simproc]
  3571 
  3572 * HOL/typedef: fixed type inference for representing set; type
  3573 arguments now have to occur explicitly on the rhs as type constraints;
  3574 
  3575 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3576 names rather than an ML expression;
  3577 
  3578 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3579 supplied later.  Program schemes can be defined, such as
  3580     "While B C s = (if B s then While B C (C s) else s)"
  3581 where the well-founded relation can be chosen after B and C have been given.
  3582 
  3583 * HOL/List: the constructors of type list are now Nil and Cons;
  3584 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3585 course, ML tools referring to List.list.op # etc. have to be adapted;
  3586 
  3587 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3588 disabled by default; run isabelle with option -m HOL to get back to
  3589 the original Gordon/HOL-style output;
  3590 
  3591 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3592 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3593 
  3594 * HOL basic syntax simplified (more orthogonal): all variants of
  3595 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3596 Eps operator is provided as well: "SOME x. P[x]";
  3597 
  3598 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3599 
  3600 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3601 thus available for user theories;
  3602 
  3603 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3604 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3605 time;
  3606 
  3607 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3608 several times and then mp;
  3609 
  3610 
  3611 *** LK ***
  3612 
  3613 * the notation <<...>> is now available as a notation for sequences of
  3614 formulas;
  3615 
  3616 * the simplifier is now installed
  3617 
  3618 * the axiom system has been generalized (thanks to Soren Heilmann)
  3619 
  3620 * the classical reasoner now has a default rule database
  3621 
  3622 
  3623 *** ZF ***
  3624 
  3625 * new primrec section allows primitive recursive functions to be given
  3626 directly (as in HOL) over datatypes and the natural numbers;
  3627 
  3628 * new tactics induct_tac and exhaust_tac for induction (or case
  3629 analysis) over datatypes and the natural numbers;
  3630 
  3631 * the datatype declaration of type T now defines the recursor T_rec;
  3632 
  3633 * simplification automatically does freeness reasoning for datatype
  3634 constructors;
  3635 
  3636 * automatic type-inference, with AddTCs command to insert new
  3637 type-checking rules;
  3638 
  3639 * datatype introduction rules are now added as Safe Introduction rules
  3640 to the claset;
  3641 
  3642 * the syntax "if P then x else y" is now available in addition to
  3643 if(P,x,y);
  3644 
  3645 
  3646 *** Internal programming interfaces ***
  3647 
  3648 * tuned simplifier trace output; new flag debug_simp;
  3649 
  3650 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3651 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3652 
  3653 * AxClass.axclass_tac lost the theory argument;
  3654 
  3655 * tuned current_goals_markers semantics: begin / end goal avoids
  3656 printing empty lines;
  3657 
  3658 * removed prs and prs_fn hook, which was broken because it did not
  3659 include \n in its semantics, forcing writeln to add one
  3660 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3661 string -> unit if you really want to output text without newline;
  3662 
  3663 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3664 plain output, interface builders may have to enable 'isabelle_font'
  3665 mode to get Isabelle font glyphs as before;
  3666 
  3667 * refined token_translation interface; INCOMPATIBILITY: output length
  3668 now of type real instead of int;
  3669 
  3670 * theory loader actions may be traced via new ThyInfo.add_hook
  3671 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3672 your own database of information attached to *whole* theories -- as
  3673 opposed to intra-theory data slots offered via TheoryDataFun;
  3674 
  3675 * proper handling of dangling sort hypotheses (at last!);
  3676 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3677 extra sort hypotheses that can be witnessed from the type signature;
  3678 the force_strip_shyps flag is gone, any remaining shyps are simply
  3679 left in the theorem (with a warning issued by strip_shyps_warning);
  3680 
  3681 
  3682 
  3683 New in Isabelle98-1 (October 1998)
  3684 ----------------------------------
  3685 
  3686 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3687 
  3688 * several changes of automated proof tools;
  3689 
  3690 * HOL: major changes to the inductive and datatype packages, including
  3691 some minor incompatibilities of theory syntax;
  3692 
  3693 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3694 called `inj_on';
  3695 
  3696 * HOL: removed duplicate thms in Arith:
  3697   less_imp_add_less  should be replaced by  trans_less_add1
  3698   le_imp_add_le      should be replaced by  trans_le_add1
  3699 
  3700 * HOL: unary minus is now overloaded (new type constraints may be
  3701 required);
  3702 
  3703 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3704 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3705 now taken as an integer constant.
  3706 
  3707 * Pure: ML function 'theory_of' renamed to 'theory';
  3708 
  3709 
  3710 *** Proof tools ***
  3711 
  3712 * Simplifier:
  3713   1. Asm_full_simp_tac is now more aggressive.
  3714      1. It will sometimes reorient premises if that increases their power to
  3715         simplify.
  3716      2. It does no longer proceed strictly from left to right but may also
  3717         rotate premises to achieve further simplification.
  3718      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3719      old Asm_full_simp_tac in that it does not rotate premises.
  3720   2. The simplifier now knows a little bit about nat-arithmetic.
  3721 
  3722 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3723 allows for selected deletion of wrappers, by introduction of names for
  3724 wrapper functionals.  This implies that addbefore, addSbefore,
  3725 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3726 and that adding two tactics with the same name overwrites the first
  3727 one (emitting a warning).
  3728   type wrapper = (int -> tactic) -> (int -> tactic)
  3729   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3730   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3731   delWrapper, delSWrapper: claset *  string            -> claset
  3732   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3733 
  3734 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3735 semantics; addbefore now affects only the unsafe part of step_tac
  3736 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3737 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3738 by Force_tac;
  3739 
  3740 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3741 compWrapper; added safe wrapper (and access functions for it);
  3742 
  3743 * HOL/split_all_tac is now much faster and fails if there is nothing
  3744 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3745 and the names of the automatically generated variables have changed.
  3746 split_all_tac has moved within claset() from unsafe wrappers to safe
  3747 wrappers, which means that !!-bound variables are split much more
  3748 aggressively, and safe_tac and clarify_tac now split such variables.
  3749 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3750 Note: the same holds for record_split_tac, which does the job of
  3751 split_all_tac for record fields.
  3752 
  3753 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3754 permanently to the default simpset using Addsplits just like
  3755 Addsimps. They can be removed via Delsplits just like
  3756 Delsimps. Lower-case versions are also available.
  3757 
  3758 * HOL/Simplifier: The rule split_if is now part of the default
  3759 simpset. This means that the simplifier will eliminate all occurrences
  3760 of if-then-else in the conclusion of a goal. To prevent this, you can
  3761 either remove split_if completely from the default simpset by
  3762 `Delsplits [split_if]' or remove it in a specific call of the
  3763 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3764 other case splitting rules to/from the default simpset: every datatype
  3765 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3766 t is the name of the datatype).
  3767 
  3768 * Classical reasoner / Simplifier combination: new force_tac (and
  3769 derivatives Force_tac, force) combines rewriting and classical
  3770 reasoning (and whatever other tools) similarly to auto_tac, but is
  3771 aimed to solve the given subgoal completely.
  3772 
  3773 
  3774 *** General ***
  3775 
  3776 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3777 and `goalw': the theory is no longer needed as an explicit argument -
  3778 the current theory context is used; assumptions are no longer returned
  3779 at the ML-level unless one of them starts with ==> or !!; it is
  3780 recommended to convert to these new commands using isatool fixgoal
  3781 (backup your sources first!);
  3782 
  3783 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3784 the current theory context, and 'theory' to lookup stored theories;
  3785 
  3786 * new theory section 'locale' for declaring constants, assumptions and
  3787 definitions that have local scope;
  3788 
  3789 * new theory section 'nonterminals' for purely syntactic types;
  3790 
  3791 * new theory section 'setup' for generic ML setup functions
  3792 (e.g. package initialization);
  3793 
  3794 * the distribution now includes Isabelle icons: see
  3795 lib/logo/isabelle-{small,tiny}.xpm;
  3796 
  3797 * isatool install - install binaries with absolute references to
  3798 ISABELLE_HOME/bin;
  3799 
  3800 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3801 
  3802 * print mode 'emacs' reserved for Isamode;
  3803 
  3804 * support multiple print (ast) translations per constant name;
  3805 
  3806 * theorems involving oracles are now printed with a suffixed [!];
  3807 
  3808 
  3809 *** HOL ***
  3810 
  3811 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3812 
  3813 * HOL/inductive package reorganized and improved: now supports mutual
  3814 definitions such as
  3815 
  3816   inductive EVEN ODD
  3817     intrs
  3818       null "0 : EVEN"
  3819       oddI "n : EVEN ==> Suc n : ODD"
  3820       evenI "n : ODD ==> Suc n : EVEN"
  3821 
  3822 new theorem list "elims" contains an elimination rule for each of the
  3823 recursive sets; inductive definitions now handle disjunctive premises
  3824 correctly (also ZF);
  3825 
  3826 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3827 "mutual_induct" no longer exists - the induction rule is always
  3828 contained in "induct";
  3829 
  3830 
  3831 * HOL/datatype package re-implemented and greatly improved: now
  3832 supports mutually recursive datatypes such as
  3833 
  3834   datatype
  3835     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3836             | SUM ('a aexp) ('a aexp)
  3837             | DIFF ('a aexp) ('a aexp)
  3838             | NUM 'a
  3839   and
  3840     'a bexp = LESS ('a aexp) ('a aexp)
  3841             | AND ('a bexp) ('a bexp)
  3842             | OR ('a bexp) ('a bexp)
  3843 
  3844 as well as indirectly recursive datatypes such as
  3845 
  3846   datatype
  3847     ('a, 'b) term = Var 'a
  3848                   | App 'b ((('a, 'b) term) list)
  3849 
  3850 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3851 induction on mutually / indirectly recursive datatypes.
  3852 
  3853 Primrec equations are now stored in theory and can be accessed via
  3854 <function_name>.simps.
  3855 
  3856 INCOMPATIBILITIES:
  3857 
  3858   - Theories using datatypes must now have theory Datatype as an
  3859     ancestor.
  3860   - The specific <typename>.induct_tac no longer exists - use the
  3861     generic induct_tac instead.
  3862   - natE has been renamed to nat.exhaust - use exhaust_tac
  3863     instead of res_inst_tac ... natE. Note that the variable
  3864     names in nat.exhaust differ from the names in natE, this
  3865     may cause some "fragile" proofs to fail.
  3866   - The theorems split_<typename>_case and split_<typename>_case_asm
  3867     have been renamed to <typename>.split and <typename>.split_asm.
  3868   - Since default sorts of type variables are now handled correctly,
  3869     some datatype definitions may have to be annotated with explicit
  3870     sort constraints.
  3871   - Primrec definitions no longer require function name and type
  3872     of recursive argument.
  3873 
  3874 Consider using isatool fixdatatype to adapt your theories and proof
  3875 scripts to the new package (backup your sources first!).
  3876 
  3877 
  3878 * HOL/record package: considerably improved implementation; now
  3879 includes concrete syntax for record types, terms, updates; theorems
  3880 for surjective pairing and splitting !!-bound record variables; proof
  3881 support is as follows:
  3882 
  3883   1) standard conversions (selectors or updates applied to record
  3884 constructor terms) are part of the standard simpset;
  3885 
  3886   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3887 made part of standard simpset and claset via addIffs;
  3888 
  3889   3) a tactic for record field splitting (record_split_tac) is part of
  3890 the standard claset (addSWrapper);
  3891 
  3892 To get a better idea about these rules you may retrieve them via
  3893 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3894 the name of your record type.
  3895 
  3896 The split tactic 3) conceptually simplifies by the following rule:
  3897 
  3898   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3899 
  3900 Thus any record variable that is bound by meta-all will automatically
  3901 blow up into some record constructor term, consequently the
  3902 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3903 solve record problems automatically.
  3904 
  3905 
  3906 * reorganized the main HOL image: HOL/Integ and String loaded by
  3907 default; theory Main includes everything;
  3908 
  3909 * automatic simplification of integer sums and comparisons, using cancellation;
  3910 
  3911 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3912 
  3913 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3914 
  3915 * many new identities for unions, intersections, set difference, etc.;
  3916 
  3917 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3918 called split_if, split_split, split_sum_case and split_nat_case (to go
  3919 with add/delsplits);
  3920 
  3921 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3922 (?x::unit) = (); this is made part of the default simpset, which COULD
  3923 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3924 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3925 unit_abs_eta_conv is added in order to counter the effect of
  3926 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3927 %u.f();
  3928 
  3929 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3930 makes more sense);
  3931 
  3932 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3933   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3934   disjointness reasoning but breaking a few old proofs.
  3935 
  3936 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3937 to 'converse' from 'inverse' (for compatibility with ZF and some
  3938 literature);
  3939 
  3940 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3941 the well-founded relation;
  3942 
  3943 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3944     Compl A.  The "Compl" syntax remains available as input syntax for this
  3945     release ONLY.
  3946 
  3947 * HOL/Update: new theory of function updates:
  3948     f(a:=b) == %x. if x=a then b else f x
  3949 may also be iterated as in f(a:=b,c:=d,...);
  3950 
  3951 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3952 
  3953 * HOL/List:
  3954   - new function list_update written xs[i:=v] that updates the i-th
  3955     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3956   - new function `upt' written [i..j(] which generates the list
  3957     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3958     bound write [i..j], which is a shorthand for [i..j+1(].
  3959   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3960 
  3961 * HOL/Arith:
  3962   - removed 'pred' (predecessor) function;
  3963   - generalized some theorems about n-1;
  3964   - many new laws about "div" and "mod";
  3965   - new laws about greatest common divisors (see theory ex/Primes);
  3966 
  3967 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3968 instead of "inverse";
  3969 
  3970 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3971   of the multiset ordering;
  3972 
  3973 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3974   (not included by default);
  3975 
  3976 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3977 
  3978 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3979   programs, i.e. different program variables may have different types.
  3980 
  3981 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3982   [previously, this check worked only if the rewrite rule was unconditional]
  3983   Now rew can involve either definitions or equalities (either == or =).
  3984 
  3985 
  3986 *** ZF ***
  3987 
  3988 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3989   only the theorems proved on ZF.ML;
  3990 
  3991 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3992   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3993   disjointness reasoning but breaking a few old proofs.
  3994 
  3995 * ZF/Update: new theory of function updates
  3996     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3997   may also be iterated as in f(a:=b,c:=d,...);
  3998 
  3999 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4000 
  4001 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4002   [previously, this check worked only if the rewrite rule was unconditional]
  4003   Now rew can involve either definitions or equalities (either == or =).
  4004 
  4005 * case_tac provided for compatibility with HOL
  4006     (like the old excluded_middle_tac, but with subgoals swapped)
  4007 
  4008 
  4009 *** Internal programming interfaces ***
  4010 
  4011 * Pure: several new basic modules made available for general use, see
  4012 also src/Pure/README;
  4013 
  4014 * improved the theory data mechanism to support encapsulation (data
  4015 kind name replaced by private Object.kind, acting as authorization
  4016 key); new type-safe user interface via functor TheoryDataFun; generic
  4017 print_data function becomes basically useless;
  4018 
  4019 * removed global_names compatibility flag -- all theory declarations
  4020 are qualified by default;
  4021 
  4022 * module Pure/Syntax now offers quote / antiquote translation
  4023 functions (useful for Hoare logic etc. with implicit dependencies);
  4024 see HOL/ex/Antiquote for an example use;
  4025 
  4026 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4027 cterm -> thm;
  4028 
  4029 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4030 subgoal;
  4031 
  4032 * Display.print_goals function moved to Locale.print_goals;
  4033 
  4034 * standard print function for goals supports current_goals_markers
  4035 variable for marking begin of proof, end of proof, start of goal; the
  4036 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4037 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4038 for example;
  4039 
  4040 
  4041 
  4042 New in Isabelle98 (January 1998)
  4043 --------------------------------
  4044 
  4045 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4046 
  4047 * changed lexical syntax of terms / types: dots made part of long
  4048 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4049 
  4050 * simpset (and claset) reference variable replaced by functions
  4051 simpset / simpset_ref;
  4052 
  4053 * no longer supports theory aliases (via merge) and non-trivial
  4054 implicit merge of thms' signatures;
  4055 
  4056 * most internal names of constants changed due to qualified names;
  4057 
  4058 * changed Pure/Sequence interface (see Pure/seq.ML);
  4059 
  4060 
  4061 *** General Changes ***
  4062 
  4063 * hierachically structured name spaces (for consts, types, axms, thms
  4064 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4065 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4066 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4067 long_names for fully qualified output names; NOTE: ML programs
  4068 (special tactics, packages etc.) referring to internal names may have
  4069 to be adapted to cope with fully qualified names; in case of severe
  4070 backward campatibility problems try setting 'global_names' at compile
  4071 time to have enrything declared within a flat name space; one may also
  4072 fine tune name declarations in theories via the 'global' and 'local'
  4073 section;
  4074 
  4075 * reimplemented the implicit simpset and claset using the new anytype
  4076 data filed in signatures; references simpset:simpset ref etc. are
  4077 replaced by functions simpset:unit->simpset and
  4078 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4079 to patch your ML files accordingly;
  4080 
  4081 * HTML output now includes theory graph data for display with Java
  4082 applet or isatool browser; data generated automatically via isatool
  4083 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4084 
  4085 * defs may now be conditional; improved rewrite_goals_tac to handle
  4086 conditional equations;
  4087 
  4088 * defs now admits additional type arguments, using TYPE('a) syntax;
  4089 
  4090 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4091 creates a new theory node; implicit merge of thms' signatures is
  4092 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4093 transfer:theory->thm->thm in (rare) cases;
  4094 
  4095 * improved handling of draft signatures / theories; draft thms (and
  4096 ctyps, cterms) are automatically promoted to real ones;
  4097 
  4098 * slightly changed interfaces for oracles: admit many per theory, named
  4099 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4100 
  4101 * print_goals: optional output of const types (set show_consts and
  4102 show_types);
  4103 
  4104 * improved output of warnings (###) and errors (***);
  4105 
  4106 * subgoal_tac displays a warning if the new subgoal has type variables;
  4107 
  4108 * removed old README and Makefiles;
  4109 
  4110 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4111 
  4112 * removed obsolete init_pps and init_database;
  4113 
  4114 * deleted the obsolete tactical STATE, which was declared by
  4115     fun STATE tacfun st = tacfun st st;
  4116 
  4117 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4118 (which abbreviates $HOME);
  4119 
  4120 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4121 use isatool fixseq to adapt your ML programs (this works for fully
  4122 qualified references to the Sequence structure only!);
  4123 
  4124 * use_thy no longer requires writable current directory; it always
  4125 reloads .ML *and* .thy file, if either one is out of date;
  4126 
  4127 
  4128 *** Classical Reasoner ***
  4129 
  4130 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4131 tactics that use classical reasoning to simplify a subgoal without
  4132 splitting it into several subgoals;
  4133 
  4134 * Safe_tac: like safe_tac but uses the default claset;
  4135 
  4136 
  4137 *** Simplifier ***
  4138 
  4139 * added simplification meta rules:
  4140     (asm_)(full_)simplify: simpset -> thm -> thm;
  4141 
  4142 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4143 logics (again);
  4144 
  4145 * added prems argument to simplification procedures;
  4146 
  4147 * HOL, FOL, ZF: added infix function `addsplits':
  4148   instead of `<simpset> setloop (split_tac <thms>)'
  4149   you can simply write `<simpset> addsplits <thms>'
  4150 
  4151 
  4152 *** Syntax ***
  4153 
  4154 * TYPE('a) syntax for type reflection terms;
  4155 
  4156 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4157 
  4158 * pretty printer: changed order of mixfix annotation preference (again!);
  4159 
  4160 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4161 
  4162 
  4163 *** HOL ***
  4164 
  4165 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4166   with `addloop' of the simplifier to faciliate case splitting in premises.
  4167 
  4168 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4169 
  4170 * HOL/Auth: new protocol proofs including some for the Internet
  4171   protocol TLS;
  4172 
  4173 * HOL/Map: new theory of `maps' a la VDM;
  4174 
  4175 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4176 cancelling out common nat summands from =, <, <= (in)equalities, or
  4177 differences; simplification procedures nat_cancel_factor for
  4178 cancelling common factor from =, <, <= (in)equalities over natural
  4179 sums; nat_cancel contains both kinds of procedures, it is installed by
  4180 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4181 
  4182 * HOL/simplifier: terms of the form
  4183   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4184   are rewritten to
  4185   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4186   and those of the form
  4187   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4188   are rewritten to
  4189   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4190 
  4191 * HOL/datatype
  4192   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4193 
  4194   P(t_case f1 ... fn x) =
  4195      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4196         ...
  4197        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4198      )
  4199 
  4200   and a theorem `split_t_case_asm' of the form
  4201 
  4202   P(t_case f1 ... fn x) =
  4203     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4204         ...
  4205        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4206      )
  4207   which can be added to a simpset via `addsplits'. The existing theorems
  4208   expand_list_case and expand_option_case have been renamed to
  4209   split_list_case and split_option_case.
  4210 
  4211 * HOL/Arithmetic:
  4212   - `pred n' is automatically converted to `n-1'.
  4213     Users are strongly encouraged not to use `pred' any longer,
  4214     because it will disappear altogether at some point.
  4215   - Users are strongly encouraged to write "0 < n" rather than
  4216     "n ~= 0". Theorems and proof tools have been modified towards this
  4217     `standard'.
  4218 
  4219 * HOL/Lists:
  4220   the function "set_of_list" has been renamed "set" (and its theorems too);
  4221   the function "nth" now takes its arguments in the reverse order and
  4222   has acquired the infix notation "!" as in "xs!n".
  4223 
  4224 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4225 
  4226 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4227   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4228 
  4229 * HOL/record: extensible records with schematic structural subtyping
  4230 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4231 still lacks various theorems and concrete record syntax;
  4232 
  4233 
  4234 *** HOLCF ***
  4235 
  4236 * removed "axioms" and "generated by" sections;
  4237 
  4238 * replaced "ops" section by extended "consts" section, which is capable of
  4239   handling the continuous function space "->" directly;
  4240 
  4241 * domain package:
  4242   . proves theorems immediately and stores them in the theory,
  4243   . creates hierachical name space,
  4244   . now uses normal mixfix annotations (instead of cinfix...),
  4245   . minor changes to some names and values (for consistency),
  4246   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4247   . separator between mutual domain defs: changed "," to "and",
  4248   . improved handling of sort constraints;  now they have to
  4249     appear on the left-hand side of the equations only;
  4250 
  4251 * fixed LAM <x,y,zs>.b syntax;
  4252 
  4253 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4254 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4255 
  4256 
  4257 *** FOL and ZF ***
  4258 
  4259 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4260   with `addloop' of the simplifier to faciliate case splitting in premises.
  4261 
  4262 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4263 in HOL, they strip ALL and --> from proved theorems;
  4264 
  4265 
  4266 
  4267 New in Isabelle94-8 (May 1997)
  4268 ------------------------------
  4269 
  4270 *** General Changes ***
  4271 
  4272 * new utilities to build / run / maintain Isabelle etc. (in parts
  4273 still somewhat experimental); old Makefiles etc. still functional;
  4274 
  4275 * new 'Isabelle System Manual';
  4276 
  4277 * INSTALL text, together with ./configure and ./build scripts;
  4278 
  4279 * reimplemented type inference for greater efficiency, better error
  4280 messages and clean internal interface;
  4281 
  4282 * prlim command for dealing with lots of subgoals (an easier way of
  4283 setting goals_limit);
  4284 
  4285 
  4286 *** Syntax ***
  4287 
  4288 * supports alternative (named) syntax tables (parser and pretty
  4289 printer); internal interface is provided by add_modesyntax(_i);
  4290 
  4291 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4292 be used in conjunction with the Isabelle symbol font; uses the
  4293 "symbols" syntax table;
  4294 
  4295 * added token_translation interface (may translate name tokens in
  4296 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4297 the current print_mode); IMPORTANT: user print translation functions
  4298 are responsible for marking newly introduced bounds
  4299 (Syntax.mark_boundT);
  4300 
  4301 * token translations for modes "xterm" and "xterm_color" that display
  4302 names in bold, underline etc. or colors (which requires a color
  4303 version of xterm);
  4304 
  4305 * infixes may now be declared with names independent of their syntax;
  4306 
  4307 * added typed_print_translation (like print_translation, but may
  4308 access type of constant);
  4309 
  4310 
  4311 *** Classical Reasoner ***
  4312 
  4313 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4314 some limitations.  Blast_tac...
  4315   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4316   + ignores elimination rules that don't have the correct format
  4317         (the conclusion MUST be a formula variable)
  4318   + ignores types, which can make HOL proofs fail
  4319   + rules must not require higher-order unification, e.g. apply_type in ZF
  4320     [message "Function Var's argument not a bound variable" relates to this]
  4321   + its proof strategy is more general but can actually be slower
  4322 
  4323 * substitution with equality assumptions no longer permutes other
  4324 assumptions;
  4325 
  4326 * minor changes in semantics of addafter (now called addaltern); renamed
  4327 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4328 (and access functions for it);
  4329 
  4330 * improved combination of classical reasoner and simplifier:
  4331   + functions for handling clasimpsets
  4332   + improvement of addss: now the simplifier is called _after_ the
  4333     safe steps.
  4334   + safe variant of addss called addSss: uses safe simplifications
  4335     _during_ the safe steps. It is more complete as it allows multiple
  4336     instantiations of unknowns (e.g. with slow_tac).
  4337 
  4338 *** Simplifier ***
  4339 
  4340 * added interface for simplification procedures (functions that
  4341 produce *proven* rewrite rules on the fly, depending on current
  4342 redex);
  4343 
  4344 * ordering on terms as parameter (used for ordered rewriting);
  4345 
  4346 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4347 
  4348 * the solver is now split into a safe and an unsafe part.
  4349 This should be invisible for the normal user, except that the
  4350 functions setsolver and addsolver have been renamed to setSolver and
  4351 addSolver; added safe_asm_full_simp_tac;
  4352 
  4353 
  4354 *** HOL ***
  4355 
  4356 * a generic induction tactic `induct_tac' which works for all datatypes and
  4357 also for type `nat';
  4358 
  4359 * a generic case distinction tactic `exhaust_tac' which works for all
  4360 datatypes and also for type `nat';
  4361 
  4362 * each datatype comes with a function `size';
  4363 
  4364 * patterns in case expressions allow tuple patterns as arguments to
  4365 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4366 
  4367 * primrec now also works with type nat;
  4368 
  4369 * recdef: a new declaration form, allows general recursive functions to be
  4370 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4371 
  4372 * the constant for negation has been renamed from "not" to "Not" to
  4373 harmonize with FOL, ZF, LK, etc.;
  4374 
  4375 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4376 infinite lists;
  4377 
  4378 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4379 
  4380 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4381 problems in commutative rings, using axiomatic type classes for + and *;
  4382 
  4383 * more examples in HOL/MiniML and HOL/Auth;
  4384 
  4385 * more default rewrite rules for quantifiers, union/intersection;
  4386 
  4387 * a new constant `arbitrary == @x.False';
  4388 
  4389 * HOLCF/IOA replaces old HOL/IOA;
  4390 
  4391 * HOLCF changes: derived all rules and arities
  4392   + axiomatic type classes instead of classes
  4393   + typedef instead of faking type definitions
  4394   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4395   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4396   + eliminated the types void, one, tr
  4397   + use unit lift and bool lift (with translations) instead of one and tr
  4398   + eliminated blift from Lift3.thy (use Def instead of blift)
  4399   all eliminated rules are derived as theorems --> no visible changes ;
  4400 
  4401 
  4402 *** ZF ***
  4403 
  4404 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4405 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4406 as ZF_cs addSIs [equalityI];
  4407 
  4408 
  4409 
  4410 New in Isabelle94-7 (November 96)
  4411 ---------------------------------
  4412 
  4413 * allowing negative levels (as offsets) in prlev and choplev;
  4414 
  4415 * super-linear speedup for large simplifications;
  4416 
  4417 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4418 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4419 FAIL); can suppress it using the command Delsimps (ex_simps @
  4420 all_simps); De Morgan laws are also now included, by default;
  4421 
  4422 * improved printing of ==>  :  ~:
  4423 
  4424 * new object-logic "Sequents" adds linear logic, while replacing LK
  4425 and Modal (thanks to Sara Kalvala);
  4426 
  4427 * HOL/Auth: correctness proofs for authentication protocols;
  4428 
  4429 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4430 examples on HOL/Auth);
  4431 
  4432 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4433 the rewriter and classical reasoner simultaneously;
  4434 
  4435 * function uresult no longer returns theorems in "standard" format;
  4436 regain previous version by: val uresult = standard o uresult;
  4437 
  4438 
  4439 
  4440 New in Isabelle94-6
  4441 -------------------
  4442 
  4443 * oracles -- these establish an interface between Isabelle and trusted
  4444 external reasoners, which may deliver results as theorems;
  4445 
  4446 * proof objects (in particular record all uses of oracles);
  4447 
  4448 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4449 
  4450 * "constdefs" section in theory files;
  4451 
  4452 * "primrec" section (HOL) no longer requires names;
  4453 
  4454 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4455 
  4456 
  4457 
  4458 New in Isabelle94-5
  4459 -------------------
  4460 
  4461 * reduced space requirements;
  4462 
  4463 * automatic HTML generation from theories;
  4464 
  4465 * theory files no longer require "..." (quotes) around most types;
  4466 
  4467 * new examples, including two proofs of the Church-Rosser theorem;
  4468 
  4469 * non-curried (1994) version of HOL is no longer distributed;
  4470 
  4471 
  4472 
  4473 New in Isabelle94-4
  4474 -------------------
  4475 
  4476 * greatly reduced space requirements;
  4477 
  4478 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4479 
  4480 * searchable theorem database (see the section "Retrieving theorems" on
  4481 page 8 of the Reference Manual);
  4482 
  4483 * new examples, including Grabczewski's monumental case study of the
  4484 Axiom of Choice;
  4485 
  4486 * The previous version of HOL renamed to Old_HOL;
  4487 
  4488 * The new version of HOL (previously called CHOL) uses a curried syntax
  4489 for functions.  Application looks like f a b instead of f(a,b);
  4490 
  4491 * Mutually recursive inductive definitions finally work in HOL;
  4492 
  4493 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4494 translates to the operator "split";
  4495 
  4496 
  4497 
  4498 New in Isabelle94-3
  4499 -------------------
  4500 
  4501 * new infix operator, addss, allowing the classical reasoner to
  4502 perform simplification at each step of its search.  Example:
  4503         fast_tac (cs addss ss)
  4504 
  4505 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4506 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4507 look like (a,b) instead of <a,b>;
  4508 
  4509 * PLEASE NOTE: CHOL will eventually replace HOL!
  4510 
  4511 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4512 It translates to the operator "split".  A new theory of integers is available;
  4513 
  4514 * In ZF, integer numerals now denote two's-complement binary integers.
  4515 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4516 
  4517 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4518 of the Axiom of Choice;
  4519 
  4520 
  4521 
  4522 New in Isabelle94-2
  4523 -------------------
  4524 
  4525 * Significantly faster resolution;
  4526 
  4527 * the different sections in a .thy file can now be mixed and repeated
  4528 freely;
  4529 
  4530 * Database of theorems for FOL, HOL and ZF.  New
  4531 commands including qed, qed_goal and bind_thm store theorems in the database.
  4532 
  4533 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4534 a given theory (thms_of), or find out what theory a theorem was proved in
  4535 (theory_of_thm);
  4536 
  4537 * Bugs fixed in the inductive definition and datatype packages;
  4538 
  4539 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4540 and HOL_dup_cs obsolete;
  4541 
  4542 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4543 have been removed;
  4544 
  4545 * Simpler definition of function space in ZF;
  4546 
  4547 * new results about cardinal and ordinal arithmetic in ZF;
  4548 
  4549 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4550 types;
  4551 
  4552 
  4553 $Id$