NEWS
author wenzelm
Tue Nov 21 20:47:58 2006 +0100 (2006-11-21)
changeset 21447 379f130843f7
parent 21406 4058f0886448
child 21462 74ddf3a522f8
permissions -rw-r--r--
* Isar: the assumptions of a long theorem statement are available as assms;
     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", "if", "fun") are
    19 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 name $A$, after
    49 checking that it refers to a valid ancestor theory in the current
    50 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 
    56 *** Pure ***
    57 
    58 * class_package.ML offers a combination of axclasses and locales to
    59 achieve Haskell-like type classes in Isabelle. See
    60 HOL/ex/Classpackage.thy for examples.
    61 
    62 * Yet another code generator framework allows to generate executable
    63 code for ML and Haskell (including "class"es). A short usage sketch:
    64 
    65     internal compilation:
    66         code_gen <list of constants (term syntax)> (SML *)
    67     writing SML code to a file:
    68         code_gen <list of constants (term syntax)> (SML <filename>)
    69     writing Haskell code to a bunch of files:
    70         code_gen <list of constants (term syntax)> (Haskell <filename>)
    71 
    72 Reasonable default setup of framework in HOL/Main.
    73 
    74 See HOL/ex/Code*.thy for examples.
    75 
    76 Theorem attributs for selecting and transforming function equations theorems:
    77 
    78     [code fun]:       select a theorem as function equation for a specific constant
    79     [code nofun]:     deselect a theorem as function equation for a specific constant
    80     [code inline]:    select an equation theorem for unfolding (inlining) in place
    81     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    82 
    83 User-defined serializations (target in {SML, Haskell}):
    84 
    85     code_const <and-list of constants (term syntax)>
    86       {(target) <and-list of const target syntax>}+
    87 
    88     code_type <and-list of type constructors>
    89       {(target) <and-list of type target syntax>}+
    90 
    91     code_instance <and-list of instances>
    92       {(target)}+
    93         where instance ::= <type constructor> :: <class>
    94 
    95     code_class <and_list of classes>
    96       {(target) <and-list of class target syntax>}+
    97         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
    98 
    99 For code_instance and code_class, target SML is silently ignored.
   100 
   101 See HOL theories and HOL/ex/Code*.thy for usage examples.  Doc/Isar/Advanced/Codegen/
   102 provides a tutorial.
   103 
   104 * Command 'no_translations' removes translation rules from theory
   105 syntax.
   106 
   107 * Overloaded definitions are now actually checked for acyclic
   108 dependencies.  The overloading scheme is slightly more general than
   109 that of Haskell98, although Isabelle does not demand an exact
   110 correspondence to type class and instance declarations.
   111 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   112 exotic versions of overloading -- at the discretion of the user!
   113 
   114 Polymorphic constants are represented via type arguments, i.e. the
   115 instantiation that matches an instance against the most general
   116 declaration given in the signature.  For example, with the declaration
   117 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   118 as c(nat).  Overloading is essentially simultaneous structural
   119 recursion over such type arguments.  Incomplete specification patterns
   120 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   121 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   122 Command 'print_theory' outputs the normalized system of recursive
   123 equations, see section "definitions".
   124 
   125 * Isar: improper proof element 'guess' is like 'obtain', but derives
   126 the obtained context from the course of reasoning!  For example:
   127 
   128   assume "EX x y. A x & B y"   -- "any previous fact"
   129   then guess x and y by clarify
   130 
   131 This technique is potentially adventurous, depending on the facts and
   132 proof tools being involved here.
   133 
   134 * Isar: known facts from the proof context may be specified as literal
   135 propositions, using ASCII back-quote syntax.  This works wherever
   136 named facts used to be allowed so far, in proof commands, proof
   137 methods, attributes etc.  Literal facts are retrieved from the context
   138 according to unification of type and term parameters.  For example,
   139 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   140 theorems in the current context, then these are valid literal facts:
   141 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   142 
   143 There is also a proof method "fact" which does the same composition
   144 for explicit goal states, e.g. the following proof texts coincide with
   145 certain special cases of literal facts:
   146 
   147   have "A" by fact                 ==  note `A`
   148   have "A ==> B" by fact           ==  note `A ==> B`
   149   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   150   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   151 
   152 * Isar: ":" (colon) is no longer a symbolic identifier character in
   153 outer syntax.  Thus symbolic identifiers may be used without
   154 additional white space in declarations like this: ``assume *: A''.
   155 
   156 * Isar: 'print_facts' prints all local facts of the current context,
   157 both named and unnamed ones.
   158 
   159 * Isar: 'def' now admits simultaneous definitions, e.g.:
   160 
   161   def x == "t" and y == "u"
   162 
   163 * Isar: added command 'unfolding', which is structurally similar to
   164 'using', but affects both the goal state and facts by unfolding given
   165 rewrite rules.  Thus many occurrences of the 'unfold' method or
   166 'unfolded' attribute may be replaced by first-class proof text.
   167 
   168 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   169 and command 'unfolding' now all support object-level equalities
   170 (potentially conditional).  The underlying notion of rewrite rule is
   171 analogous to the 'rule_format' attribute, but *not* that of the
   172 Simplifier (which is usually more generous).
   173 
   174 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   175 method expression within a sandbox consisting of the first N
   176 sub-goals, which need to exist.  For example, ``simp_all [3]''
   177 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   178 simplifies all new goals that emerge from applying rule foo to the
   179 originally first one.
   180 
   181 * Isar: schematic goals are no longer restricted to higher-order
   182 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   183 expected.
   184 
   185 * Isar: the conclusion of a long theorem statement is now either
   186 'shows' (a simultaneous conjunction, as before), or 'obtains'
   187 (essentially a disjunction of cases with local parameters and
   188 assumptions).  The latter allows to express general elimination rules
   189 adequately; in this notation common elimination rules look like this:
   190 
   191   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   192     assumes "EX x. P x"
   193     obtains x where "P x"
   194 
   195   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   196     assumes "A & B"
   197     obtains A and B
   198 
   199   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   200     assumes "A | B"
   201     obtains
   202       A
   203     | B
   204 
   205 The subsequent classical rules even refer to the formal "thesis"
   206 explicitly:
   207 
   208   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   209     obtains "~ thesis"
   210 
   211   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   212     obtains "thesis ==> something"
   213 
   214 The actual proof of an 'obtains' statement is analogous to that of the
   215 Isar proof element 'obtain', only that there may be several cases.
   216 Optional case names may be specified in parentheses; these will be
   217 available both in the present proof and as annotations in the
   218 resulting rule, for later use with the 'cases' method (cf. attribute
   219 case_names).
   220 
   221 * Isar: the assumptions of a long theorem statement are available as
   222 "assms" fact in the proof context.  This is more appropriate than the
   223 (historical) "prems", which refers to all assumptions of the current
   224 context, including those from the target locale, proof body etc.
   225 
   226 * Isar: 'print_statement' prints theorems from the current theory or
   227 proof context in long statement form, according to the syntax of a
   228 top-level lemma.
   229 
   230 * Isar: 'obtain' takes an optional case name for the local context
   231 introduction rule (default "that").
   232 
   233 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   234 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   235 to occur.
   236 
   237 * Pure: syntax "CONST name" produces a fully internalized constant
   238 according to the current context.  This is particularly useful for
   239 syntax translations that should refer to internal constant
   240 representations independently of name spaces.
   241 
   242 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   243 primitive that also works in a locale context (both for constants and
   244 fixed variables).  Type declaration and internal syntactic
   245 representation of given constants retrieved from the context.
   246 
   247 * Isar/locales: new derived specification elements 'axiomatization',
   248 'definition', 'abbreviation', which support type-inference, admit
   249 object-level specifications (equality, equivalence).  See also the
   250 isar-ref manual.  Examples:
   251 
   252   axiomatization
   253     eq  (infix "===" 50)
   254     where eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   255 
   256   definition
   257     "f x y = x + y + 1"
   258     "g x = f x x"
   259 
   260   abbreviation
   261     neq  (infix "=!=" 50)
   262     "x =!= y == ~ (x === y)"
   263 
   264 These specifications may be also used in a locale context.  Then the
   265 constants being introduced depend on certain fixed parameters, and the
   266 constant name is qualified by the locale base name.  An internal
   267 abbreviation takes care for convenient input and output, making the
   268 parameters implicit and using the original short name.  See also
   269 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   270 entities from a monomorphic theory.
   271 
   272 Presently, abbreviations are only available 'in' a target locale, but
   273 not inherited by general import expressions.  Also note that
   274 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   275 'translations' in common applications.
   276 
   277 Concrete syntax is attached to specified constants in internal form,
   278 independently of name spaces.  The parse tree representation is
   279 slightly different -- use 'notation' instead of raw 'syntax', and
   280 'translations' with explicit "CONST" markup to accommodate this.
   281 
   282 * Isar/locales: improved parameter handling:
   283 - use of locales "var" and "struct" no longer necessary;
   284 - parameter renamings are no longer required to be injective.
   285   This enables, for example, to define a locale for endomorphisms thus:
   286   locale endom = homom mult mult h.
   287 
   288 * Isar/locales: changed the way locales with predicates are defined.
   289 Instead of accumulating the specification, the imported expression is
   290 now an interpretation.
   291 INCOMPATIBILITY: different normal form of locale expressions.
   292 In particular, in interpretations of locales with predicates,
   293 goals repesenting already interpreted fragments are not removed
   294 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   295 
   296 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   297 backward reasoning on locales predicates.  The methods are aware of
   298 interpretations and discharge corresponding goals.  `intro_locales' is
   299 less aggressive then `unfold_locales' and does not unfold predicates to
   300 assumptions.
   301 
   302 * Isar/locales: the order in which locale fragments are accumulated
   303 has changed.  This enables to override declarations from fragments
   304 due to interpretations -- for example, unwanted simp rules.
   305 
   306 * Provers/induct: improved internal context management to support
   307 local fixes and defines on-the-fly.  Thus explicit meta-level
   308 connectives !! and ==> are rarely required anymore in inductive goals
   309 (using object-logic connectives for this purpose has been long
   310 obsolete anyway).  The subsequent proof patterns illustrate advanced
   311 techniques of natural induction; general datatypes and inductive sets
   312 work analogously (see also src/HOL/Lambda for realistic examples).
   313 
   314 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   315 parameters:
   316 
   317   lemma
   318     fixes n :: nat and x :: 'a
   319     assumes a: "A n x"
   320     shows "P n x"
   321     using a                     -- {* make induct insert fact a *}
   322   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   323     case 0
   324     show ?case sorry
   325   next
   326     case (Suc n)
   327     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   328     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   329     show ?case sorry
   330   qed
   331 
   332 (2) This is how to perform induction over ``expressions of a certain
   333 form'', using a locally defined inductive parameter n == "a x"
   334 together with strengthening (the latter is usually required to get
   335 sufficiently flexible induction hypotheses):
   336 
   337   lemma
   338     fixes a :: "'a => nat"
   339     assumes a: "A (a x)"
   340     shows "P (a x)"
   341     using a
   342   proof (induct n == "a x" arbitrary: x)
   343     ...
   344 
   345 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   346 particular technique.
   347 
   348 (3) This is how to perform existential reasoning ('obtains' or
   349 'obtain') by induction, while avoiding explicit object-logic
   350 encodings:
   351 
   352   lemma
   353     fixes n :: nat
   354     obtains x :: 'a where "P n x" and "Q n x"
   355   proof (induct n arbitrary: thesis)
   356     case 0
   357     obtain x where "P 0 x" and "Q 0 x" sorry
   358     then show thesis by (rule 0)
   359   next
   360     case (Suc n)
   361     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   362     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   363     then show thesis by (rule Suc.prems)
   364   qed
   365 
   366 Here the 'arbitrary: thesis' specification essentially modifies the
   367 scope of the formal thesis parameter, in order to the get the whole
   368 existence statement through the induction as expected.
   369 
   370 * Provers/induct: mutual induction rules are now specified as a list
   371 of rule sharing the same induction cases.  HOL packages usually
   372 provide foo_bar.inducts for mutually defined items foo and bar
   373 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   374 specify mutual induction rules differently, i.e. like this:
   375 
   376   (induct rule: foo_bar.inducts)
   377   (induct set: foo bar)
   378   (induct type: foo bar)
   379 
   380 The ML function ProjectRule.projections turns old-style rules into the
   381 new format.
   382 
   383 * Provers/induct: improved handling of simultaneous goals.  Instead of
   384 introducing object-level conjunction, the statement is now split into
   385 several conclusions, while the corresponding symbolic cases are
   386 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   387 explicitly.  For example:
   388 
   389   lemma
   390     fixes n :: nat
   391     shows "P n" and "Q n"
   392   proof (induct n)
   393     case 0 case 1
   394     show "P 0" sorry
   395   next
   396     case 0 case 2
   397     show "Q 0" sorry
   398   next
   399     case (Suc n) case 1
   400     note `P n` and `Q n`
   401     show "P (Suc n)" sorry
   402   next
   403     case (Suc n) case 2
   404     note `P n` and `Q n`
   405     show "Q (Suc n)" sorry
   406   qed
   407 
   408 The split into subcases may be deferred as follows -- this is
   409 particularly relevant for goal statements with local premises.
   410 
   411   lemma
   412     fixes n :: nat
   413     shows "A n ==> P n" and "B n ==> Q n"
   414   proof (induct n)
   415     case 0
   416     {
   417       case 1
   418       note `A 0`
   419       show "P 0" sorry
   420     next
   421       case 2
   422       note `B 0`
   423       show "Q 0" sorry
   424     }
   425   next
   426     case (Suc n)
   427     note `A n ==> P n` and `B n ==> Q n`
   428     {
   429       case 1
   430       note `A (Suc n)`
   431       show "P (Suc n)" sorry
   432     next
   433       case 2
   434       note `B (Suc n)`
   435       show "Q (Suc n)" sorry
   436     }
   437   qed
   438 
   439 If simultaneous goals are to be used with mutual rules, the statement
   440 needs to be structured carefully as a two-level conjunction, using
   441 lists of propositions separated by 'and':
   442 
   443   lemma
   444     shows "a : A ==> P1 a"
   445           "a : A ==> P2 a"
   446       and "b : B ==> Q1 b"
   447           "b : B ==> Q2 b"
   448           "b : B ==> Q3 b"
   449   proof (induct set: A B)
   450 
   451 * Provers/induct: support coinduction as well.  See
   452 src/HOL/Library/Coinductive_List.thy for various examples.
   453 
   454 * Attribute "symmetric" produces result with standardized schematic
   455 variables (index 0).  Potential INCOMPATIBILITY.
   456 
   457 * Simplifier: by default the simplifier trace only shows top level rewrites
   458 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   459 less danger of being flooded by the trace. The trace indicates where parts
   460 have been suppressed.
   461   
   462 * Provers/classical: removed obsolete classical version of elim_format
   463 attribute; classical elim/dest rules are now treated uniformly when
   464 manipulating the claset.
   465 
   466 * Provers/classical: stricter checks to ensure that supplied intro,
   467 dest and elim rules are well-formed; dest and elim rules must have at
   468 least one premise.
   469 
   470 * Provers/classical: attributes dest/elim/intro take an optional
   471 weight argument for the rule (just as the Pure versions).  Weights are
   472 ignored by automated tools, but determine the search order of single
   473 rule steps.
   474 
   475 * Syntax: input syntax now supports dummy variable binding "%_. b",
   476 where the body does not mention the bound variable.  Note that dummy
   477 patterns implicitly depend on their context of bounds, which makes
   478 "{_. _}" match any set comprehension as expected.  Potential
   479 INCOMPATIBILITY -- parse translations need to cope with syntactic
   480 constant "_idtdummy" in the binding position.
   481 
   482 * Syntax: removed obsolete syntactic constant "_K" and its associated
   483 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   484 for example "A -> B" => "Pi A (%_. B)".
   485 
   486 * Pure: 'class_deps' command visualizes the subclass relation, using
   487 the graph browser tool.
   488 
   489 * Pure: 'print_theory' now suppresses entities with internal name
   490 (trailing "_") by default; use '!' option for full details.
   491 
   492 
   493 *** HOL ***
   494 
   495 * New syntactic class "size"; overloaded constant "size" now
   496 has type "'a::size ==> bool"
   497 
   498 * Constants "Divides.op div", "Divides.op mod" and "Divides.op dvd" no named
   499   "Divides.div", "Divides.mod" and "Divides.dvd"
   500   INCOMPATIBILITY for ML code directly refering to constant names.
   501 
   502 * Replaced "auto_term" by the conceptually simpler method "relation",
   503 which just applies the instantiated termination rule with no further
   504 simplifications.
   505 INCOMPATIBILITY: 
   506 Replace 
   507         termination by (auto_term "MYREL")
   508 with 
   509         termination by (relation "MYREL") auto
   510 
   511 * Automated termination proofs "by lexicographic_order" are now
   512 included in the abbreviated function command "fun". No explicit
   513 "termination" command is necessary anymore.
   514 INCOMPATIBILITY: If a "fun"-definition cannot be proved terminating by
   515 a lexicographic size order, then the command fails. Use the expanded
   516 version "function" for these cases.
   517 
   518 * New method "lexicographic_order" automatically synthesizes
   519 termination relations as lexicographic combinations of size measures. 
   520 Usage for (function package) termination proofs:
   521 
   522 termination 
   523 by lexicographic_order
   524 
   525 * Records: generalised field-update to take a function on the field 
   526 rather than the new value: r(|A := x|) is translated to A_update (K x) r
   527 The K-combinator that is internally used is called K_record.
   528 INCOMPATIBILITY: Usage of the plain update functions has to be
   529 adapted.
   530  
   531 * axclass "semiring_0" now contains annihilation axioms 
   532 ("x * 0 = 0","0 * x = 0"), which are required for a semiring. Richer 
   533 structures do not inherit from semiring_0 anymore, because this property 
   534 is a theorem there, not an axiom.
   535 INCOMPATIBILITY: In instances of semiring_0, there is more to prove, but 
   536 this is mostly trivial.
   537 
   538 * axclass "recpower" was generalized to arbitrary monoids, not just 
   539 commutative semirings.
   540 INCOMPATIBILITY: If you use recpower and need commutativity or a semiring
   541 property, add the corresponding classes.
   542 
   543 * Locale Lattic_Locales.partial_order changed (to achieve consistency with
   544   axclass order):
   545   - moved to Orderings.partial_order
   546   - additional parameter ``less''
   547   INCOMPATIBILITY.
   548 
   549 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   550 INCOMPATIBILITY: translations containing list_all2 may go wrong. On Isar
   551 level, use abbreviations instead.
   552 
   553 * Constant "List.op mem" in List.thy now has proper name: "List.memberl"
   554 INCOMPATIBILITY: rarely occuring name references (e.g. ``List.op mem.simps'')
   555 require renaming (e.g. ``List.memberl.simps'').
   556 
   557 * Renamed constants in HOL.thy:
   558     0      ~> HOL.zero
   559     1      ~> HOL.one
   560 INCOMPATIBILITY: ML code directly refering to constant names may need adaption
   561 This in general only affects hand-written proof tactics, simprocs and so on.
   562 
   563 * New theory Code_Generator providing class 'eq' with constant 'eq',
   564 allowing for code generation with polymorphic equality.
   565 
   566 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has been
   567 abandoned in favour of plain 'int'. INCOMPATIBILITY -- Significant changes
   568 for setting up numeral syntax for types:
   569 
   570   - new constants Numeral.pred and Numeral.succ instead
   571       of former Numeral.bin_pred and Numeral.bin_succ.
   572   - Use integer operations instead of bin_add, bin_mult and so on.
   573   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   574   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   575 
   576 See HOL/Integ/IntArith.thy for an example setup.
   577 
   578 * New top level command 'normal_form' computes the normal form of a term
   579 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   580 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   581 because the functions are compiled to ML first.
   582 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   583 an identifier.
   584 
   585 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   586 25 like -->); output depends on the "iff" print_mode, the default is
   587 "A = B" (with priority 50).
   588 
   589 * Renamed constants in HOL.thy and Orderings.thy:
   590     op +   ~> HOL.plus
   591     op -   ~> HOL.minus
   592     uminus ~> HOL.uminus
   593     op *   ~> HOL.times
   594     op <   ~> Orderings.less
   595     op <=  ~> Orderings.less_eq
   596 
   597 Adaptions may be required in the following cases:
   598 
   599 a) User-defined constants using any of the names "plus", "minus", "times",
   600 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   601 may go wrong.
   602 INCOMPATIBILITY: use more specific names.
   603 
   604 b) Variables named "plus", "minus", "times", "less", "less_eq"
   605 INCOMPATIBILITY: use more specific names.
   606 
   607 c) Permutative equations (e.g. "a + b = b + a")
   608 Since the change of names also changes the order of terms, permutative
   609 rewrite rules may get applied in a different order. Experience shows that
   610 this is rarely the case (only two adaptions in the whole Isabelle
   611 distribution).
   612 INCOMPATIBILITY: rewrite proofs
   613 
   614 d) ML code directly refering to constant names
   615 This in general only affects hand-written proof tactics, simprocs and so on.
   616 INCOMPATIBILITY: grep your sourcecode and replace names.
   617 
   618 * Relations less (<) and less_eq (<=) are also available on type bool.
   619 Modified syntax to disallow nesting without explicit parentheses,
   620 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   621 
   622 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   623 
   624 * Relation composition operator "op O" now has precedence 75 and binds
   625 stronger than union and intersection. INCOMPATIBILITY.
   626 
   627 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   628   Use "{m..<n}" (and relatives) instead.
   629 
   630 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   631 "t = s" to False (by simproc "neq_simproc").  For backward
   632 compatibility this can be disabled by ML "reset use_neq_simproc".
   633 
   634 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   635 
   636 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   637 
   638 * Theorem setsum_mult renamed to setsum_right_distrib.
   639 
   640 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   641 'rule' method.
   642 
   643 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   644 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   645 "=" on type bool) are handled, variable names of the form "lit_<n>"
   646 are no longer reserved, significant speedup.
   647 
   648 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   649 still supported as well.
   650 
   651 * inductive and datatype: provide projections of mutual rules, bundled
   652 as foo_bar.inducts;
   653 
   654 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to Library.
   655 
   656 * Library: moved theory Accessible_Part to main HOL.
   657 
   658 * Library: added theory Coinductive_List of potentially infinite lists
   659 as greatest fixed-point.
   660 
   661 * Library: added theory AssocList which implements (finite) maps as
   662 association lists.
   663 
   664 * New proof method "evaluation" for efficiently solving a goal (i.e. a
   665 boolean expression) by compiling it to ML. The goal is "proved" (via
   666 the oracle "Evaluation") if it evaluates to True.
   667 
   668 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   669 also when invoked by the simplifier.  This results in the simplifier
   670 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   671 fast_arith_split_limit to 0 to obtain the old behavior.
   672 
   673 * Support for hex (0x20) and binary (0b1001) numerals. 
   674 
   675 * New method: reify eqs (t), where eqs are equations for an
   676 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   677 parameter, computes a term s::'b and a list xs::'a list and proves the
   678 theorem I xs s = t. This is also known as reification or quoting. The
   679 resulting theorem is applied to the subgoal to substitute t with I xs
   680 s.  If t is omitted, the subgoal itself is reified.
   681 
   682 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   683 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   684 where f is supposed to be a computable function (in the sense of code
   685 generattion). The method uses reify to compute s and xs as above then
   686 applies corr_thm and uses normalization by evaluation to "prove" f s =
   687 r and finally gets the theorem t = r, which is again applied to the
   688 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   689 
   690 * Reflection: Automatic refification now handels binding, an example
   691 is available in HOL/ex/ReflectionEx.thy
   692 
   693 
   694 *** HOL-Algebra ***
   695 
   696 * Formalisation of ideals and the quotient construction over rings.
   697 
   698 * Order and lattice theory no longer based on records.
   699 INCOMPATIBILITY.
   700 
   701 * Method algebra is now set up via an attribute.  For examples see
   702 CRing.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   703 of algebraic structures.
   704 
   705 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.
   706 
   707 
   708 *** HOL-Complex ***
   709 
   710 * Theory Real: new method ferrack implements quantifier elimination
   711 for linear arithmetic over the reals. The quantifier elimination
   712 feature is used only for decision, for compatibility with arith. This
   713 means a goal is either solved or left unchanged, no simplification.
   714 
   715 
   716 *** ML ***
   717 
   718 * Pure/table:
   719 
   720 Function `...tab.foldl` removed.
   721 INCOMPATIBILITY: use `...tabfold` instead
   722 
   723 * Pure/library:
   724 
   725 `gen_rem(s)` abandoned in favour of `remove` / `subtract`.
   726 INCOMPATIBILITY:
   727 rewrite "gen_rem eq (xs, x)" to "remove (eq o swap) x xs"
   728 rewrite "gen_rems eq (xs, ys)" to "subtract (eq o swap) ys xs"
   729 drop "swap" if "eq" is symmetric.
   730 
   731 * Pure/library:
   732 
   733 infixes `ins` `ins_string` `ins_int` have been abandoned in favour of `insert`.
   734 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"
   735 
   736 * Pure/General/susp.ML:
   737 
   738 New module for delayed evaluations.
   739 
   740 * Pure/library:
   741 
   742 Semantically identical functions "equal_list" and "eq_list" have been
   743 unified to "eq_list".
   744 
   745 * Pure/library:
   746 
   747   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   748   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   749 
   750 The semantics of "burrow" is: "take a function with *simulatanously*
   751 transforms a list of value, and apply it *simulatanously* to a list of
   752 list of values of the appropriate type". Confer this with "map" which
   753 would *not* apply its argument function simulatanously but in
   754 sequence. "fold_burrow" has an additional context.
   755 
   756 Both actually avoid the usage of "unflat" since they hide away
   757 "unflat" from the user.
   758 
   759 * Pure/library: functions map2 and fold2 with curried syntax for
   760 simultanous mapping and folding:
   761 
   762     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   763     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   764 
   765 * Pure/library: indexed lists - some functions in the Isabelle library
   766 treating lists over 'a as finite mappings from [0...n] to 'a have been
   767 given more convenient names and signatures reminiscent of similar
   768 functions for alists, tables, etc:
   769 
   770   val nth: 'a list -> int -> 'a 
   771   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   772   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   773 
   774 Note that fold_index starts counting at index 0, not 1 like foldln
   775 used to.
   776 
   777 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   778 
   779 * Pure/General/name_mangler.ML provides a functor for generic name
   780 mangling (bijective mapping from expression values to strings).
   781 
   782 * Pure/General/rat.ML implements rational numbers.
   783 
   784 * Pure/General/table.ML: the join operations now works via exceptions
   785 DUP/SAME instead of type option.  This is simpler in simple cases, and
   786 admits slightly more efficient complex applications.
   787 
   788 * Pure: datatype Context.generic joins theory/Proof.context and
   789 provides some facilities for code that works in either kind of
   790 context, notably GenericDataFun for uniform theory and proof data.
   791 
   792 * Pure: 'advanced' translation functions (parse_translation etc.) now
   793 use Context.generic instead of just theory.
   794 
   795 * Pure: simplified internal attribute type, which is now always
   796 Context.generic * thm -> Context.generic * thm.  Global (theory)
   797 vs. local (Proof.context) attributes have been discontinued, while
   798 minimizing code duplication.  Thm.rule_attribute and
   799 Thm.declaration_attribute build canonical attributes; see also
   800 structure Context for further operations on Context.generic, notably
   801 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   802 declarations and definitions.
   803 
   804 * Pure/kernel: consts certification ignores sort constraints given in
   805 signature declarations.  (This information is not relevant to the
   806 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   807 
   808 * Pure: axiomatic type classes are now purely definitional, with
   809 explicit proofs of class axioms and super class relations performed
   810 internally.  See Pure/axclass.ML for the main internal interfaces --
   811 notably AxClass.define_class supercedes AxClass.add_axclass, and
   812 AxClass.axiomatize_class/classrel/arity supercede
   813 Sign.add_classes/classrel/arities.
   814 
   815 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   816 global/local versions on theory vs. Proof.context have been
   817 discontinued; Attrib.syntax and Method.syntax have been adapted
   818 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   819 attributes, methods, etc.
   820 
   821 * Pure: several functions of signature "... -> theory -> theory * ..."
   822 have been reoriented to "... -> theory -> ... * theory" in order to
   823 allow natural usage in combination with the ||>, ||>>, |-> and
   824 fold_map combinators.
   825 
   826 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   827 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   828 achieve the old behaviour.
   829 
   830 * Pure: the "Goal" constant is now called "prop", supporting a
   831 slightly more general idea of ``protecting'' meta-level rule
   832 statements.
   833 
   834 * Pure: Logic.(un)varify only works in a global context, which is now
   835 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   836 Logic.legacy_(un)varify as temporary workaround.
   837 
   838 * Pure: structure Name provides scalable operations for generating
   839 internal variable names, notably Name.variants etc.  This replaces
   840 some popular functions from term.ML:
   841 
   842   Term.variant		->  Name.variant
   843   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   844   Term.invent_names	->  Name.invent_list
   845 
   846 Note that low-level renaming rarely occurs in new code -- operations
   847 from structure Variable are used instead (see below).
   848 
   849 * Pure: structure Variable provides fundamental operations for proper
   850 treatment of fixed/schematic variables in a context.  For example,
   851 Variable.import introduces fixes for schematics of given facts and
   852 Variable.export reverses the effect (up to renaming) -- this replaces
   853 various freeze_thaw operations.
   854 
   855 * Pure: structure Goal provides simple interfaces for
   856 init/conclude/finish and tactical prove operations (replacing former
   857 Tactic.prove).  Goal.prove is the canonical way to prove results
   858 within a given context; Goal.prove_global is a degraded version for
   859 theory level goals, including a global Drule.standard.  Note that
   860 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   861 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   862 in a locale context).
   863 
   864 * Isar: simplified treatment of user-level errors, using exception
   865 ERROR of string uniformly.  Function error now merely raises ERROR,
   866 without any side effect on output channels.  The Isar toplevel takes
   867 care of proper display of ERROR exceptions.  ML code may use plain
   868 handle/can/try; cat_error may be used to concatenate errors like this:
   869 
   870   ... handle ERROR msg => cat_error msg "..."
   871 
   872 Toplevel ML code (run directly or through the Isar toplevel) may be
   873 embedded into the Isar toplevel with exception display/debug like
   874 this:
   875 
   876   Isar.toplevel (fn () => ...)
   877 
   878 INCOMPATIBILITY, removed special transform_error facilities, removed
   879 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   880 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   881 -- use plain ERROR instead.
   882 
   883 * Isar: theory setup now has type (theory -> theory), instead of a
   884 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   885 
   886 * Isar: installed ML toplevel pretty printer for type Proof.context,
   887 subject to ProofContext.debug/verbose flags.
   888 
   889 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   890 theory before entering a proof state.  Transactions now always see a
   891 quasi-functional intermediate checkpoint, both in interactive and
   892 batch mode.
   893 
   894 * Simplifier: the simpset of a running simplification process now
   895 contains a proof context (cf. Simplifier.the_context), which is the
   896 very context that the initial simpset has been retrieved from (by
   897 simpset_of/local_simpset_of).  Consequently, all plug-in components
   898 (solver, looper etc.) may depend on arbitrary proof data.
   899 
   900 * Simplifier.inherit_context inherits the proof context (plus the
   901 local bounds) of the current simplification process; any simproc
   902 etc. that calls the Simplifier recursively should do this!  Removed
   903 former Simplifier.inherit_bounds, which is already included here --
   904 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   905 specify an explicit context using Simplifier.context/theory_context.
   906 
   907 * Simplifier/Classical Reasoner: more abstract interfaces
   908 change_simpset/claset for modifying the simpset/claset reference of a
   909 theory; raw versions simpset/claset_ref etc. have been discontinued --
   910 INCOMPATIBILITY.
   911 
   912 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   913 "Trueprop" etc.
   914 
   915 
   916 *** System ***
   917 
   918 * isabelle-process: option -S (secure mode) disables some critical
   919 operations, notably runtime compilation and evaluation of ML source
   920 code.
   921 
   922 
   923 New in Isabelle2005 (October 2005)
   924 ----------------------------------
   925 
   926 *** General ***
   927 
   928 * Theory headers: the new header syntax for Isar theories is
   929 
   930   theory <name>
   931   imports <theory1> ... <theoryN>
   932   uses <file1> ... <fileM>
   933   begin
   934 
   935 where the 'uses' part is optional.  The previous syntax
   936 
   937   theory <name> = <theory1> + ... + <theoryN>:
   938 
   939 will disappear in the next release.  Use isatool fixheaders to convert
   940 existing theory files.  Note that there is no change in ancient
   941 non-Isar theories now, but these will disappear soon.
   942 
   943 * Theory loader: parent theories can now also be referred to via
   944 relative and absolute paths.
   945 
   946 * Command 'find_theorems' searches for a list of criteria instead of a
   947 list of constants. Known criteria are: intro, elim, dest, name:string,
   948 simp:term, and any term. Criteria can be preceded by '-' to select
   949 theorems that do not match. Intro, elim, dest select theorems that
   950 match the current goal, name:s selects theorems whose fully qualified
   951 name contain s, and simp:term selects all simplification rules whose
   952 lhs match term.  Any other term is interpreted as pattern and selects
   953 all theorems matching the pattern. Available in ProofGeneral under
   954 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   955 
   956   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   957 
   958 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   959 matching the current goal as introduction rule and not having "HOL."
   960 in their name (i.e. not being defined in theory HOL).
   961 
   962 * Command 'thms_containing' has been discontinued in favour of
   963 'find_theorems'; INCOMPATIBILITY.
   964 
   965 * Communication with Proof General is now 8bit clean, which means that
   966 Unicode text in UTF-8 encoding may be used within theory texts (both
   967 formal and informal parts).  Cf. option -U of the Isabelle Proof
   968 General interface.  Here are some simple examples (cf. src/HOL/ex):
   969 
   970   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   971   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   972 
   973 * Improved efficiency of the Simplifier and, to a lesser degree, the
   974 Classical Reasoner.  Typical big applications run around 2 times
   975 faster.
   976 
   977 
   978 *** Document preparation ***
   979 
   980 * Commands 'display_drafts' and 'print_drafts' perform simple output
   981 of raw sources.  Only those symbols that do not require additional
   982 LaTeX packages (depending on comments in isabellesym.sty) are
   983 displayed properly, everything else is left verbatim.  isatool display
   984 and isatool print are used as front ends (these are subject to the
   985 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   986 
   987 * Command tags control specific markup of certain regions of text,
   988 notably folding and hiding.  Predefined tags include "theory" (for
   989 theory begin and end), "proof" for proof commands, and "ML" for
   990 commands involving ML code; the additional tags "visible" and
   991 "invisible" are unused by default.  Users may give explicit tag
   992 specifications in the text, e.g. ''by %invisible (auto)''.  The
   993 interpretation of tags is determined by the LaTeX job during document
   994 preparation: see option -V of isatool usedir, or options -n and -t of
   995 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   996 \isadroptag.
   997 
   998 Several document versions may be produced at the same time via isatool
   999 usedir (the generated index.html will link all of them).  Typical
  1000 specifications include ''-V document=theory,proof,ML'' to present
  1001 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1002 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1003 these parts without any formal replacement text.  The Isabelle site
  1004 default settings produce ''document'' and ''outline'' versions as
  1005 specified above.
  1006 
  1007 * Several new antiquotations:
  1008 
  1009   @{term_type term} prints a term with its type annotated;
  1010 
  1011   @{typeof term} prints the type of a term;
  1012 
  1013   @{const const} is the same as @{term const}, but checks that the
  1014   argument is a known logical constant;
  1015 
  1016   @{term_style style term} and @{thm_style style thm} print a term or
  1017   theorem applying a "style" to it
  1018 
  1019   @{ML text}
  1020 
  1021 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1022 definitions, equations, inequations etc., 'concl' printing only the
  1023 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1024 to print the specified premise.  TermStyle.add_style provides an ML
  1025 interface for introducing further styles.  See also the "LaTeX Sugar"
  1026 document practical applications.  The ML antiquotation prints
  1027 type-checked ML expressions verbatim.
  1028 
  1029 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1030 and 'text' support optional locale specification '(in loc)', which
  1031 specifies the default context for interpreting antiquotations.  For
  1032 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1033 
  1034 * Option 'locale=NAME' of antiquotations specifies an alternative
  1035 context interpreting the subsequent argument.  For example: @{thm
  1036 [locale=lattice] inf_assoc}.
  1037 
  1038 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1039 a proof context.
  1040 
  1041 * Proper output of antiquotations for theory commands involving a
  1042 proof context (such as 'locale' or 'theorem (in loc) ...').
  1043 
  1044 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1045 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1046 
  1047 * isatool usedir: new option -C (default true) controls whether option
  1048 -D should include a copy of the original document directory; -C false
  1049 prevents unwanted effects such as copying of administrative CVS data.
  1050 
  1051 
  1052 *** Pure ***
  1053 
  1054 * Considerably improved version of 'constdefs' command.  Now performs
  1055 automatic type-inference of declared constants; additional support for
  1056 local structure declarations (cf. locales and HOL records), see also
  1057 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1058 sequential dependencies of definitions within a single 'constdefs'
  1059 section; moreover, the declared name needs to be an identifier.  If
  1060 all fails, consider to fall back on 'consts' and 'defs' separately.
  1061 
  1062 * Improved indexed syntax and implicit structures.  First of all,
  1063 indexed syntax provides a notational device for subscripted
  1064 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1065 expressions.  Secondly, in a local context with structure
  1066 declarations, number indexes \<^sub>n or the empty index (default
  1067 number 1) refer to a certain fixed variable implicitly; option
  1068 show_structs controls printing of implicit structures.  Typical
  1069 applications of these concepts involve record types and locales.
  1070 
  1071 * New command 'no_syntax' removes grammar declarations (and
  1072 translations) resulting from the given syntax specification, which is
  1073 interpreted in the same manner as for the 'syntax' command.
  1074 
  1075 * 'Advanced' translation functions (parse_translation etc.) may depend
  1076 on the signature of the theory context being presently used for
  1077 parsing/printing, see also isar-ref manual.
  1078 
  1079 * Improved 'oracle' command provides a type-safe interface to turn an
  1080 ML expression of type theory -> T -> term into a primitive rule of
  1081 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1082 is already included here); see also FOL/ex/IffExample.thy;
  1083 INCOMPATIBILITY.
  1084 
  1085 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1086 before); "cI" is no longer bound, use "c.intro" instead.
  1087 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1088 axclasses vs. locales.
  1089 
  1090 * Improved internal renaming of symbolic identifiers -- attach primes
  1091 instead of base 26 numbers.
  1092 
  1093 * New flag show_question_marks controls printing of leading question
  1094 marks in schematic variable names.
  1095 
  1096 * In schematic variable names, *any* symbol following \<^isub> or
  1097 \<^isup> is now treated as part of the base name.  For example, the
  1098 following works without printing of awkward ".0" indexes:
  1099 
  1100   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1101     by simp
  1102 
  1103 * Inner syntax includes (*(*nested*) comments*).
  1104 
  1105 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1106 annotations as "(00...)".
  1107 
  1108 * Clear separation of logical types and nonterminals, where the latter
  1109 may only occur in 'syntax' specifications or type abbreviations.
  1110 Before that distinction was only partially implemented via type class
  1111 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1112 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1113 exotic syntax specifications may require further adaption
  1114 (e.g. Cube/Cube.thy).
  1115 
  1116 * Removed obsolete type class "logic", use the top sort {} instead.
  1117 Note that non-logical types should be declared as 'nonterminals'
  1118 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1119 specifications.
  1120 
  1121 * Attributes 'induct' and 'cases': type or set names may now be
  1122 locally fixed variables as well.
  1123 
  1124 * Simplifier: can now control the depth to which conditional rewriting
  1125 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1126 Limit.
  1127 
  1128 * Simplifier: simplification procedures may now take the current
  1129 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1130 interface), which is very useful for calling the Simplifier
  1131 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1132 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1133 low-level mk_simproc no longer applies Logic.varify internally, to
  1134 allow for use in a context of fixed variables.
  1135 
  1136 * thin_tac now works even if the assumption being deleted contains !!
  1137 or ==>.  More generally, erule now works even if the major premise of
  1138 the elimination rule contains !! or ==>.
  1139 
  1140 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1141 
  1142 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1143 from Pure, which contains all common declarations already.  Both
  1144 theories are defined via plain Isabelle/Isar .thy files.
  1145 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1146 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1147 use isatool fixcpure to adapt your theory and ML sources.
  1148 
  1149 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1150 selections of theorems in named facts via index ranges.
  1151 
  1152 * 'print_theorems': in theory mode, really print the difference
  1153 wrt. the last state (works for interactive theory development only),
  1154 in proof mode print all local facts (cf. 'print_facts');
  1155 
  1156 * 'hide': option '(open)' hides only base names.
  1157 
  1158 * More efficient treatment of intermediate checkpoints in interactive
  1159 theory development.
  1160 
  1161 * Code generator is now invoked via code_module (incremental code
  1162 generation) and code_library (modular code generation, ML structures
  1163 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1164 must be quoted when used as identifiers.
  1165 
  1166 * New 'value' command for reading, evaluating and printing terms using
  1167 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1168 quoted when used as identifier.
  1169 
  1170 
  1171 *** Locales ***
  1172 
  1173 * New commands for the interpretation of locale expressions in
  1174 theories (1), locales (2) and proof contexts (3).  These generate
  1175 proof obligations from the expression specification.  After the
  1176 obligations have been discharged, theorems of the expression are added
  1177 to the theory, target locale or proof context.  The synopsis of the
  1178 commands is a follows:
  1179 
  1180   (1) interpretation expr inst
  1181   (2) interpretation target < expr
  1182   (3) interpret expr inst
  1183 
  1184 Interpretation in theories and proof contexts require a parameter
  1185 instantiation of terms from the current context.  This is applied to
  1186 specifications and theorems of the interpreted expression.
  1187 Interpretation in locales only permits parameter renaming through the
  1188 locale expression.  Interpretation is smart in that interpretations
  1189 that are active already do not occur in proof obligations, neither are
  1190 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1191 inspect active interpretations of a particular locale.  For details,
  1192 see the Isar Reference manual.  Examples can be found in
  1193 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1194 
  1195 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1196 'interpret' instead.
  1197 
  1198 * New context element 'constrains' for adding type constraints to
  1199 parameters.
  1200 
  1201 * Context expressions: renaming of parameters with syntax
  1202 redeclaration.
  1203 
  1204 * Locale declaration: 'includes' disallowed.
  1205 
  1206 * Proper static binding of attribute syntax -- i.e. types / terms /
  1207 facts mentioned as arguments are always those of the locale definition
  1208 context, independently of the context of later invocations.  Moreover,
  1209 locale operations (renaming and type / term instantiation) are applied
  1210 to attribute arguments as expected.
  1211 
  1212 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1213 actual attributes; rare situations may require Attrib.attribute to
  1214 embed those attributes into Attrib.src that lack concrete syntax.
  1215 Attribute implementations need to cooperate properly with the static
  1216 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1217 Attrib.XXX_thm etc. already do the right thing without further
  1218 intervention.  Only unusual applications -- such as "where" or "of"
  1219 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1220 on the context and the facts involved -- may have to assign parsed
  1221 values to argument tokens explicitly.
  1222 
  1223 * Changed parameter management in theorem generation for long goal
  1224 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1225 theorem statement in rare situations.
  1226 
  1227 * Locale inspection command 'print_locale' omits notes elements.  Use
  1228 'print_locale!' to have them included in the output.
  1229 
  1230 
  1231 *** Provers ***
  1232 
  1233 * Provers/hypsubst.ML: improved version of the subst method, for
  1234 single-step rewriting: it now works in bound variable contexts. New is
  1235 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1236 rewrite a different subterm than the original subst method, which is
  1237 still available as 'simplesubst'.
  1238 
  1239 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1240 and quasi orders.
  1241 
  1242 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1243 reflexive-transitive closure of relations.
  1244 
  1245 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1246 limit (previously hard-coded with a value of 20) user-definable.
  1247 
  1248 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1249 is peformed already.  Object-logics merely need to finish their
  1250 initial simpset configuration as before.  INCOMPATIBILITY.
  1251 
  1252 
  1253 *** HOL ***
  1254 
  1255 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1256 
  1257   syntax (epsilon)
  1258     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1259 
  1260 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1261 and x-symbol; use option '-m epsilon' to get it actually printed.
  1262 Moreover, the mathematically important symbolic identifier \<epsilon>
  1263 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1264 
  1265 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1266 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1267 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1268 support corresponding Isar calculations.
  1269 
  1270 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1271 instead of ":".
  1272 
  1273 * theory SetInterval: changed the syntax for open intervals:
  1274 
  1275   Old       New
  1276   {..n(}    {..<n}
  1277   {)n..}    {n<..}
  1278   {m..n(}   {m..<n}
  1279   {)m..n}   {m<..n}
  1280   {)m..n(}  {m<..<n}
  1281 
  1282 The old syntax is still supported but will disappear in the next
  1283 release.  For conversion use the following Emacs search and replace
  1284 patterns (these are not perfect but work quite well):
  1285 
  1286   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1287   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1288 
  1289 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1290 equalities in commutative rings; method 'algebra' provides a generic
  1291 interface.
  1292 
  1293 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1294 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1295 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1296 be a tuple pattern.
  1297 
  1298 Some new syntax forms are available:
  1299 
  1300   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1301   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1302   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1303   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1304 
  1305 The latter form "\<Sum>x < k. e" used to be based on a separate
  1306 function "Summation", which has been discontinued.
  1307 
  1308 * theory Finite_Set: in structured induction proofs, the insert case
  1309 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1310 (insert F x)'.
  1311 
  1312 * The 'refute' command has been extended to support a much larger
  1313 fragment of HOL, including axiomatic type classes, constdefs and
  1314 typedefs, inductive datatypes and recursion.
  1315 
  1316 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1317 Requires zChaff with proof generation to be installed.  See
  1318 HOL/ex/SAT_Examples.thy for examples.
  1319 
  1320 * Datatype induction via method 'induct' now preserves the name of the
  1321 induction variable. For example, when proving P(xs::'a list) by
  1322 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1323 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1324 in unstructured proof scripts.
  1325 
  1326 * Reworked implementation of records.  Improved scalability for
  1327 records with many fields, avoiding performance problems for type
  1328 inference. Records are no longer composed of nested field types, but
  1329 of nested extension types. Therefore the record type only grows linear
  1330 in the number of extensions and not in the number of fields.  The
  1331 top-level (users) view on records is preserved.  Potential
  1332 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1333 old record representation. The type generated for a record is called
  1334 <record_name>_ext_type.
  1335 
  1336 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1337 proofs triggered by a record definition or a simproc (if
  1338 quick_and_dirty is enabled).  Definitions of large records can take
  1339 quite long.
  1340 
  1341 New simproc record_upd_simproc for simplification of multiple record
  1342 updates enabled by default.  Moreover, trivial updates are also
  1343 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1344 occasionally, since simplification is more powerful by default.
  1345 
  1346 * typedef: proper support for polymorphic sets, which contain extra
  1347 type-variables in the term.
  1348 
  1349 * Simplifier: automatically reasons about transitivity chains
  1350 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1351 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1352 old proofs break occasionally as simplification may now solve more
  1353 goals than previously.
  1354 
  1355 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1356 present.  Works for all partial orders (class "order"), in particular
  1357 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1358 just like y <= x.
  1359 
  1360 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1361 bound variable or a constant then the let is unfolded.  Otherwise
  1362 first a is simplified to b, and then f b is simplified to g. If
  1363 possible we abstract b from g arriving at "let x = b in h x",
  1364 otherwise we unfold the let and arrive at g.  The simproc can be
  1365 enabled/disabled by the reference use_let_simproc.  Potential
  1366 INCOMPATIBILITY since simplification is more powerful by default.
  1367 
  1368 * Classical reasoning: the meson method now accepts theorems as arguments.
  1369 
  1370 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1371 jobs to provide advice on the provability of subgoals.
  1372 
  1373 * Theory OrderedGroup and Ring_and_Field: various additions and
  1374 improvements to faciliate calculations involving equalities and
  1375 inequalities.
  1376 
  1377 The following theorems have been eliminated or modified
  1378 (INCOMPATIBILITY):
  1379 
  1380   abs_eq             now named abs_of_nonneg
  1381   abs_of_ge_0        now named abs_of_nonneg
  1382   abs_minus_eq       now named abs_of_nonpos
  1383   imp_abs_id         now named abs_of_nonneg
  1384   imp_abs_neg_id     now named abs_of_nonpos
  1385   mult_pos           now named mult_pos_pos
  1386   mult_pos_le        now named mult_nonneg_nonneg
  1387   mult_pos_neg_le    now named mult_nonneg_nonpos
  1388   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1389   mult_neg           now named mult_neg_neg
  1390   mult_neg_le        now named mult_nonpos_nonpos
  1391 
  1392 * Theory Parity: added rules for simplifying exponents.
  1393 
  1394 * Theory List:
  1395 
  1396 The following theorems have been eliminated or modified
  1397 (INCOMPATIBILITY):
  1398 
  1399   list_all_Nil       now named list_all.simps(1)
  1400   list_all_Cons      now named list_all.simps(2)
  1401   list_all_conv      now named list_all_iff
  1402   set_mem_eq         now named mem_iff
  1403 
  1404 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1405 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1406 
  1407 
  1408 *** HOL-Complex ***
  1409 
  1410 * Theory RealDef: better support for embedding natural numbers and
  1411 integers in the reals.
  1412 
  1413 The following theorems have been eliminated or modified
  1414 (INCOMPATIBILITY):
  1415 
  1416   exp_ge_add_one_self  now requires no hypotheses
  1417   real_of_int_add      reversed direction of equality (use [symmetric])
  1418   real_of_int_minus    reversed direction of equality (use [symmetric])
  1419   real_of_int_diff     reversed direction of equality (use [symmetric])
  1420   real_of_int_mult     reversed direction of equality (use [symmetric])
  1421 
  1422 * Theory RComplete: expanded support for floor and ceiling functions.
  1423 
  1424 * Theory Ln is new, with properties of the natural logarithm
  1425 
  1426 * Hyperreal: There is a new type constructor "star" for making
  1427 nonstandard types.  The old type names are now type synonyms:
  1428 
  1429   hypreal = real star
  1430   hypnat = nat star
  1431   hcomplex = complex star
  1432 
  1433 * Hyperreal: Many groups of similarly-defined constants have been
  1434 replaced by polymorphic versions (INCOMPATIBILITY):
  1435 
  1436   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1437 
  1438   starset      <-- starsetNat, starsetC
  1439   *s*          <-- *sNat*, *sc*
  1440   starset_n    <-- starsetNat_n, starsetC_n
  1441   *sn*         <-- *sNatn*, *scn*
  1442   InternalSets <-- InternalNatSets, InternalCSets
  1443 
  1444   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1445   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1446   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1447   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1448   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1449 
  1450 * Hyperreal: Many type-specific theorems have been removed in favor of
  1451 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1452 
  1453   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1454   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1455   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1456   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1457   right_minus <-- hypreal_add_minus
  1458   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1459   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1460   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1461   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1462   mult_1_right <-- hcomplex_mult_one_right
  1463   mult_zero_left <-- hcomplex_mult_zero_left
  1464   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1465   right_distrib <-- hypnat_add_mult_distrib2
  1466   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1467   right_inverse <-- hypreal_mult_inverse
  1468   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1469   order_refl <-- {hypreal,hypnat}_le_refl
  1470   order_trans <-- {hypreal,hypnat}_le_trans
  1471   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1472   order_less_le <-- {hypreal,hypnat}_less_le
  1473   linorder_linear <-- {hypreal,hypnat}_le_linear
  1474   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1475   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1476   add_nonneg_nonneg <-- hypreal_le_add_order
  1477 
  1478 * Hyperreal: Separate theorems having to do with type-specific
  1479 versions of constants have been merged into theorems that apply to the
  1480 new polymorphic constants (INCOMPATIBILITY):
  1481 
  1482   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1483   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1484   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1485   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1486   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1487   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1488   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1489   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1490   STAR_diff <-- {STAR,STARC}_diff
  1491   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1492     STARC_hcomplex_of_complex}_image_subset
  1493   starset_n_Un <-- starset{Nat,C}_n_Un
  1494   starset_n_Int <-- starset{Nat,C}_n_Int
  1495   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1496   starset_n_diff <-- starset{Nat,C}_n_diff
  1497   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1498   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1499   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1500   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1501   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1502   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1503   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1504   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1505   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1506   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1507   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1508   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1509   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1510   starfun_diff <-- starfun{C,RC,CR}_diff
  1511   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1512   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1513   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1514   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1515   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1516   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1517   starfun_Id <-- starfunC_Id
  1518   starfun_approx <-- starfun{Nat,CR}_approx
  1519   starfun_capprox <-- starfun{C,RC}_capprox
  1520   starfun_abs <-- starfunNat_rabs
  1521   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1522   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1523   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1524   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1525   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1526   starfun_add_approx <-- starfunCR_add_approx
  1527   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1528   starfun_divide <-- starfun{C,CR,RC}_divide
  1529   starfun_n <-- starfun{Nat,C}_n
  1530   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1531   starfun_n_add <-- starfun{Nat,C}_n_add
  1532   starfun_n_add_minus <-- starfunNat_n_add_minus
  1533   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1534   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1535   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1536 
  1537   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1538   star_n_minus <-- {hypreal,hcomplex}_minus
  1539   star_n_diff <-- {hypreal,hcomplex}_diff
  1540   star_n_mult <-- {hypreal,hcomplex}_mult
  1541   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1542   star_n_le <-- {hypreal,hypnat}_le
  1543   star_n_less <-- {hypreal,hypnat}_less
  1544   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1545   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1546   star_n_abs <-- hypreal_hrabs
  1547   star_n_divide <-- hcomplex_divide
  1548 
  1549   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1550   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1551   star_of_diff <-- hypreal_of_real_diff
  1552   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1553   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1554   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1555   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1556   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1557   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1558   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1559   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1560   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1561   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1562   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1563   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1564   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1565   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1566   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1567   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1568   star_of_power <-- hypreal_of_real_power
  1569   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1570 
  1571 * Hyperreal: new method "transfer" that implements the transfer
  1572 principle of nonstandard analysis. With a subgoal that mentions
  1573 nonstandard types like "'a star", the command "apply transfer"
  1574 replaces it with an equivalent one that mentions only standard types.
  1575 To be successful, all free variables must have standard types; non-
  1576 standard variables must have explicit universal quantifiers.
  1577 
  1578 * Hyperreal: A theory of Taylor series.
  1579 
  1580 
  1581 *** HOLCF ***
  1582 
  1583 * Discontinued special version of 'constdefs' (which used to support
  1584 continuous functions) in favor of the general Pure one with full
  1585 type-inference.
  1586 
  1587 * New simplification procedure for solving continuity conditions; it
  1588 is much faster on terms with many nested lambda abstractions (cubic
  1589 instead of exponential time).
  1590 
  1591 * New syntax for domain package: selector names are now optional.
  1592 Parentheses should be omitted unless argument is lazy, for example:
  1593 
  1594   domain 'a stream = cons "'a" (lazy "'a stream")
  1595 
  1596 * New command 'fixrec' for defining recursive functions with pattern
  1597 matching; defining multiple functions with mutual recursion is also
  1598 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1599 sinr, or any data constructor defined by the domain package. The given
  1600 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1601 syntax and examples.
  1602 
  1603 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1604 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1605 but the proof obligation additionally includes an admissibility
  1606 requirement. The packages generate instances of class cpo or pcpo,
  1607 with continuity and strictness theorems for Rep and Abs.
  1608 
  1609 * HOLCF: Many theorems have been renamed according to a more standard naming
  1610 scheme (INCOMPATIBILITY):
  1611 
  1612   foo_inject:  "foo$x = foo$y ==> x = y"
  1613   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1614   foo_less:    "(foo$x << foo$y) = (x << y)"
  1615   foo_strict:  "foo$UU = UU"
  1616   foo_defined: "... ==> foo$x ~= UU"
  1617   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1618 
  1619 
  1620 *** ZF ***
  1621 
  1622 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1623 including the First Isomorphism Theorem (on quotienting by the kernel
  1624 of a homomorphism).
  1625 
  1626 * ZF/Simplifier: install second copy of type solver that actually
  1627 makes use of TC rules declared to Isar proof contexts (or locales);
  1628 the old version is still required for ML proof scripts.
  1629 
  1630 
  1631 *** Cube ***
  1632 
  1633 * Converted to Isar theory format; use locales instead of axiomatic
  1634 theories.
  1635 
  1636 
  1637 *** ML ***
  1638 
  1639 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1640 for ||>, ||>>, |>>,
  1641 
  1642 * Pure/library.ML no longer defines its own option datatype, but uses
  1643 that of the SML basis, which has constructors NONE and SOME instead of
  1644 None and Some, as well as exception Option.Option instead of OPTION.
  1645 The functions the, if_none, is_some, is_none have been adapted
  1646 accordingly, while Option.map replaces apsome.
  1647 
  1648 * Pure/library.ML: the exception LIST has been given up in favour of
  1649 the standard exceptions Empty and Subscript, as well as
  1650 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1651 superceded by the standard hd and tl functions etc.
  1652 
  1653 A number of basic list functions are no longer exported to the ML
  1654 toplevel, as they are variants of predefined functions.  The following
  1655 suggests how one can translate existing code:
  1656 
  1657     rev_append xs ys = List.revAppend (xs, ys)
  1658     nth_elem (i, xs) = List.nth (xs, i)
  1659     last_elem xs = List.last xs
  1660     flat xss = List.concat xss
  1661     seq fs = List.app fs
  1662     partition P xs = List.partition P xs
  1663     mapfilter f xs = List.mapPartial f xs
  1664 
  1665 * Pure/library.ML: several combinators for linear functional
  1666 transformations, notably reverse application and composition:
  1667 
  1668   x |> f                f #> g
  1669   (x, y) |-> f          f #-> g
  1670 
  1671 * Pure/library.ML: introduced/changed precedence of infix operators:
  1672 
  1673   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1674   infix 2 ?;
  1675   infix 3 o oo ooo oooo;
  1676   infix 4 ~~ upto downto;
  1677 
  1678 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1679 infix operators.
  1680 
  1681 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1682 fold_map support linear functional transformations and nesting.  For
  1683 example:
  1684 
  1685   fold f [x1, ..., xN] y =
  1686     y |> f x1 |> ... |> f xN
  1687 
  1688   (fold o fold) f [xs1, ..., xsN] y =
  1689     y |> fold f xs1 |> ... |> fold f xsN
  1690 
  1691   fold f [x1, ..., xN] =
  1692     f x1 #> ... #> f xN
  1693 
  1694   (fold o fold) f [xs1, ..., xsN] =
  1695     fold f xs1 #> ... #> fold f xsN
  1696 
  1697 * Pure/library.ML: the following selectors on type 'a option are
  1698 available:
  1699 
  1700   the:               'a option -> 'a  (*partial*)
  1701   these:             'a option -> 'a  where 'a = 'b list
  1702   the_default: 'a -> 'a option -> 'a
  1703   the_list:          'a option -> 'a list
  1704 
  1705 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1706 basic operations for association lists, following natural argument
  1707 order; moreover the explicit equality predicate passed here avoids
  1708 potentially expensive polymorphic runtime equality checks.
  1709 The old functions may be expressed as follows:
  1710 
  1711   assoc = uncurry (AList.lookup (op =))
  1712   assocs = these oo AList.lookup (op =)
  1713   overwrite = uncurry (AList.update (op =)) o swap
  1714 
  1715 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1716 
  1717   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1718   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1719 
  1720 replacing make_keylist and keyfilter (occassionally used)
  1721 Naive rewrites:
  1722 
  1723   make_keylist = AList.make
  1724   keyfilter = AList.find (op =)
  1725 
  1726 * eq_fst and eq_snd now take explicit equality parameter, thus
  1727   avoiding eqtypes. Naive rewrites:
  1728 
  1729     eq_fst = eq_fst (op =)
  1730     eq_snd = eq_snd (op =)
  1731 
  1732 * Removed deprecated apl and apr (rarely used).
  1733   Naive rewrites:
  1734 
  1735     apl (n, op) =>>= curry op n
  1736     apr (op, m) =>>= fn n => op (n, m)
  1737 
  1738 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1739 provides a reasonably efficient light-weight implementation of sets as
  1740 lists.
  1741 
  1742 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1743 few new operations; existing lookup and update are now curried to
  1744 follow natural argument order (for use with fold etc.);
  1745 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1746 
  1747 * Pure/General: output via the Isabelle channels of
  1748 writeln/warning/error etc. is now passed through Output.output, with a
  1749 hook for arbitrary transformations depending on the print_mode
  1750 (cf. Output.add_mode -- the first active mode that provides a output
  1751 function wins).  Already formatted output may be embedded into further
  1752 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1753 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1754 accommodate easy composition of diagnostic messages etc.  Programmers
  1755 rarely need to care about Output.output or Output.raw at all, with
  1756 some notable exceptions: Output.output is required when bypassing the
  1757 standard channels (writeln etc.), or in token translations to produce
  1758 properly formatted results; Output.raw is required when capturing
  1759 already output material that will eventually be presented to the user
  1760 a second time.  For the default print mode, both Output.output and
  1761 Output.raw have no effect.
  1762 
  1763 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1764 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1765 cumulative results are displayed at the end of a batch session.
  1766 
  1767 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1768 replaced by File.platform_path and File.shell_path (with appropriate
  1769 hooks).  This provides a clean interface for unusual systems where the
  1770 internal and external process view of file names are different.
  1771 
  1772 * Pure: more efficient orders for basic syntactic entities: added
  1773 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1774 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1775 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1776 orders now -- potential INCOMPATIBILITY for code that depends on a
  1777 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1778 Library.sort_strings on result).
  1779 
  1780 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1781 fold_types traverse types/terms from left to right, observing natural
  1782 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1783 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1784 
  1785 * Pure: name spaces have been refined, with significant changes of the
  1786 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1787 to extern(_table).  The plain name entry path is superceded by a
  1788 general 'naming' context, which also includes the 'policy' to produce
  1789 a fully qualified name and external accesses of a fully qualified
  1790 name; NameSpace.extend is superceded by context dependent
  1791 Sign.declare_name.  Several theory and proof context operations modify
  1792 the naming context.  Especially note Theory.restore_naming and
  1793 ProofContext.restore_naming to get back to a sane state; note that
  1794 Theory.add_path is no longer sufficient to recover from
  1795 Theory.absolute_path in particular.
  1796 
  1797 * Pure: new flags short_names (default false) and unique_names
  1798 (default true) for controlling output of qualified names.  If
  1799 short_names is set, names are printed unqualified.  If unique_names is
  1800 reset, the name prefix is reduced to the minimum required to achieve
  1801 the original result when interning again, even if there is an overlap
  1802 with earlier declarations.
  1803 
  1804 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1805 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1806 (useful for printing error messages).  INCOMPATIBILITY.
  1807 
  1808 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1809 Theory.theory are now identified, referring to the universal
  1810 Context.theory (see Pure/context.ML).  Actual signature and theory
  1811 content is managed as theory data.  The old code and interfaces were
  1812 spread over many files and structures; the new arrangement introduces
  1813 considerable INCOMPATIBILITY to gain more clarity:
  1814 
  1815   Context -- theory management operations (name, identity, inclusion,
  1816     parents, ancestors, merge, etc.), plus generic theory data;
  1817 
  1818   Sign -- logical signature and syntax operations (declaring consts,
  1819     types, etc.), plus certify/read for common entities;
  1820 
  1821   Theory -- logical theory operations (stating axioms, definitions,
  1822     oracles), plus a copy of logical signature operations (consts,
  1823     types, etc.); also a few basic management operations (Theory.copy,
  1824     Theory.merge, etc.)
  1825 
  1826 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1827 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1828 for convenience -- they merely return the theory.
  1829 
  1830 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1831 
  1832 * Pure: the Isar proof context type is already defined early in Pure
  1833 as Context.proof (note that ProofContext.context and Proof.context are
  1834 aliases, where the latter is the preferred name).  This enables other
  1835 Isabelle components to refer to that type even before Isar is present.
  1836 
  1837 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1838 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1839 any of these kinds.  For example, Sign.intern typeK is now
  1840 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1841 Theory.hide_types.  Also note that former
  1842 Theory.hide_classes/types/consts are now
  1843 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1844 internalize their arguments!  INCOMPATIBILITY.
  1845 
  1846 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1847 datatype thmref (with constructors Name and NameSelection) instead of
  1848 plain string -- INCOMPATIBILITY;
  1849 
  1850 * Pure: cases produced by proof methods specify options, where NONE
  1851 means to remove case bindings -- INCOMPATIBILITY in
  1852 (RAW_)METHOD_CASES.
  1853 
  1854 * Pure: the following operations retrieve axioms or theorems from a
  1855 theory node or theory hierarchy, respectively:
  1856 
  1857   Theory.axioms_of: theory -> (string * term) list
  1858   Theory.all_axioms_of: theory -> (string * term) list
  1859   PureThy.thms_of: theory -> (string * thm) list
  1860   PureThy.all_thms_of: theory -> (string * thm) list
  1861 
  1862 * Pure: print_tac now outputs the goal through the trace channel.
  1863 
  1864 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1865 Reference Toplevel.debug (default false) controls detailed printing
  1866 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1867 controls execution profiling -- set to 1 for time and 2 for space
  1868 (both increase the runtime).
  1869 
  1870 * Isar session: The initial use of ROOT.ML is now always timed,
  1871 i.e. the log will show the actual process times, in contrast to the
  1872 elapsed wall-clock time that the outer shell wrapper produces.
  1873 
  1874 * Simplifier: improved handling of bound variables (nameless
  1875 representation, avoid allocating new strings).  Simprocs that invoke
  1876 the Simplifier recursively should use Simplifier.inherit_bounds to
  1877 avoid local name clashes.  Failure to do so produces warnings
  1878 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1879 for further details.
  1880 
  1881 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1882 bindings for all theorems stored within a given theory; this may help
  1883 in porting non-Isar theories to Isar ones, while keeping ML proof
  1884 scripts for the time being.
  1885 
  1886 * ML operator HTML.with_charset specifies the charset begin used for
  1887 generated HTML files.  For example:
  1888 
  1889   HTML.with_charset "utf-8" use_thy "Hebrew";
  1890   HTML.with_charset "utf-8" use_thy "Chinese";
  1891 
  1892 
  1893 *** System ***
  1894 
  1895 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1896 isabelle, isatool etc.).
  1897 
  1898 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1899 isatool doc, isatool mkdir, display_drafts etc.).
  1900 
  1901 * isatool usedir: option -f allows specification of the ML file to be
  1902 used by Isabelle; default is ROOT.ML.
  1903 
  1904 * New isatool version outputs the version identifier of the Isabelle
  1905 distribution being used.
  1906 
  1907 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1908 (containing Boolean satisfiability problems) into Isabelle/HOL
  1909 theories.
  1910 
  1911 
  1912 
  1913 New in Isabelle2004 (April 2004)
  1914 --------------------------------
  1915 
  1916 *** General ***
  1917 
  1918 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1919   Replaces linorder.ML.
  1920 
  1921 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1922   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1923   (\<a>...\<z>), are now considered normal letters, and can therefore
  1924   be used anywhere where an ASCII letter (a...zA...Z) has until
  1925   now. COMPATIBILITY: This obviously changes the parsing of some
  1926   terms, especially where a symbol has been used as a binder, say
  1927   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1928   as an identifier.  Fix it by inserting a space around former
  1929   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1930   existing theory and ML files.
  1931 
  1932 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1933 
  1934 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1935   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1936   a normal (but invisible) letter. For multiple letter subscripts repeat
  1937   \<^isub> like this: x\<^isub>1\<^isub>2.
  1938 
  1939 * Pure: There are now sub-/superscripts that can span more than one
  1940   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1941   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1942   superscript. The new control characters are not identifier parts.
  1943 
  1944 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1945   content of "..." to the latex file instead of \isacntrl... . The "..."
  1946   may consist of any printable characters excluding the end bracket >.
  1947 
  1948 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1949   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1950   declare constants "final", which prevents their being given a definition
  1951   later.  It is useful for constants whose behaviour is fixed axiomatically
  1952   rather than definitionally, such as the meta-logic connectives.
  1953 
  1954 * Pure: 'instance' now handles general arities with general sorts
  1955   (i.e. intersections of classes),
  1956 
  1957 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1958   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1959   It can be changed to alter the colors/layout of generated pages.
  1960 
  1961 
  1962 *** Isar ***
  1963 
  1964 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1965   cut_tac, subgoal_tac and thin_tac:
  1966   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1967     locales are no longer forced to write Isar proof scripts.
  1968     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1969     emulations.
  1970   - INCOMPATIBILITY: names of variables to be instantiated may no
  1971     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1972     This is consistent with the instantiation attribute "where".
  1973 
  1974 * Attributes "where" and "of":
  1975   - Now take type variables of instantiated theorem into account when reading
  1976     the instantiation string.  This fixes a bug that caused instantiated
  1977     theorems to have too special types in some circumstances.
  1978   - "where" permits explicit instantiations of type variables.
  1979 
  1980 * Calculation commands "moreover" and "also" no longer interfere with
  1981   current facts ("this"), admitting arbitrary combinations with "then"
  1982   and derived forms.
  1983 
  1984 * Locales:
  1985   - Goal statements involving the context element "includes" no longer
  1986     generate theorems with internal delta predicates (those ending on
  1987     "_axioms") in the premise.
  1988     Resolve particular premise with <locale>.intro to obtain old form.
  1989   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1990     specification and "includes" elements in goal statement.
  1991   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1992     [intro?] and [elim?] (respectively) by default.
  1993   - Experimental command for instantiation of locales in proof contexts:
  1994         instantiate <label>[<attrs>]: <loc>
  1995     Instantiates locale <loc> and adds all its theorems to the current context
  1996     taking into account their attributes.  Label and attrs are optional
  1997     modifiers, like in theorem declarations.  If present, names of
  1998     instantiated theorems are qualified with <label>, and the attributes
  1999     <attrs> are applied after any attributes these theorems might have already.
  2000       If the locale has assumptions, a chained fact of the form
  2001     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2002     are derived.  The command does not support old-style locales declared
  2003     with "locale (open)".
  2004       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2005 
  2006 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2007   (Isar) contexts.
  2008 
  2009 
  2010 *** HOL ***
  2011 
  2012 * Proof import: new image HOL4 contains the imported library from
  2013   the HOL4 system with about 2500 theorems. It is imported by
  2014   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2015   can be used like any other Isabelle image.  See
  2016   HOL/Import/HOL/README for more information.
  2017 
  2018 * Simplifier:
  2019   - Much improved handling of linear and partial orders.
  2020     Reasoners for linear and partial orders are set up for type classes
  2021     "linorder" and "order" respectively, and are added to the default simpset
  2022     as solvers.  This means that the simplifier can build transitivity chains
  2023     to solve goals from the assumptions.
  2024   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2025     of blast or auto after simplification become unnecessary because the goal
  2026     is solved by simplification already.
  2027 
  2028 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2029     all proved in axiomatic type classes for semirings, rings and fields.
  2030 
  2031 * Numerics:
  2032   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2033     now formalized using the Ring_and_Field theory mentioned above.
  2034   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2035     than before, because now they are set up once in a generic manner.
  2036   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2037     Look for the general versions in Ring_and_Field (and Power if they concern
  2038     exponentiation).
  2039 
  2040 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2041 
  2042 * Records:
  2043   - Record types are now by default printed with their type abbreviation
  2044     instead of the list of all field types. This can be configured via
  2045     the reference "print_record_type_abbr".
  2046   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2047     (not enabled by default).
  2048   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2049     EX x. x = sel r to True (not enabled by default).
  2050   - Tactic "record_split_simp_tac" to split and simplify records added.
  2051 
  2052 * 'specification' command added, allowing for definition by
  2053   specification.  There is also an 'ax_specification' command that
  2054   introduces the new constants axiomatically.
  2055 
  2056 * arith(_tac) is now able to generate counterexamples for reals as well.
  2057 
  2058 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2059 
  2060 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2061   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2062 
  2063 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2064   matrix theory to linear programming.
  2065 
  2066 * Unions and Intersections:
  2067   The latex output syntax of UN and INT has been changed
  2068   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2069   i.e. the index formulae has become a subscript.
  2070   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2071 
  2072 * Unions and Intersections over Intervals:
  2073   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2074   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2075   like in normal math, and corresponding versions for < and for intersection.
  2076 
  2077 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2078   lexicographic dictonary ordering has been added as "lexord".
  2079 
  2080 * ML: the legacy theory structures Int and List have been removed. They had
  2081   conflicted with ML Basis Library structures having the same names.
  2082 
  2083 * 'refute' command added to search for (finite) countermodels.  Only works
  2084   for a fragment of HOL.  The installation of an external SAT solver is
  2085   highly recommended.  See "HOL/Refute.thy" for details.
  2086 
  2087 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2088   formulae under an assignment of free variables to random values.
  2089   In contrast to 'refute', it can deal with inductive datatypes,
  2090   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2091   for examples.
  2092 
  2093 
  2094 *** HOLCF ***
  2095 
  2096 * Streams now come with concatenation and are part of the HOLCF image
  2097 
  2098 
  2099 
  2100 New in Isabelle2003 (May 2003)
  2101 ------------------------------
  2102 
  2103 *** General ***
  2104 
  2105 * Provers/simplifier:
  2106 
  2107   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2108     Assumptions are now subject to complete mutual simplification,
  2109     not just from left to right. The simplifier now preserves
  2110     the order of assumptions.
  2111 
  2112     Potential INCOMPATIBILITY:
  2113 
  2114     -- simp sometimes diverges where the old version did
  2115        not, e.g. invoking simp on the goal
  2116 
  2117         [| P (f x); y = x; f x = f y |] ==> Q
  2118 
  2119        now gives rise to the infinite reduction sequence
  2120 
  2121         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2122 
  2123        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2124        kind of problem.
  2125 
  2126     -- Tactics combining classical reasoner and simplification (such as auto)
  2127        are also affected by this change, because many of them rely on
  2128        simp. They may sometimes diverge as well or yield a different numbers
  2129        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2130        in case of problems. Sometimes subsequent calls to the classical
  2131        reasoner will fail because a preceeding call to the simplifier too
  2132        eagerly simplified the goal, e.g. deleted redundant premises.
  2133 
  2134   - The simplifier trace now shows the names of the applied rewrite rules
  2135 
  2136   - You can limit the number of recursive invocations of the simplifier
  2137     during conditional rewriting (where the simplifie tries to solve the
  2138     conditions before applying the rewrite rule):
  2139     ML "simp_depth_limit := n"
  2140     where n is an integer. Thus you can force termination where previously
  2141     the simplifier would diverge.
  2142 
  2143   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2144 
  2145   - No longer aborts on failed congruence proof.  Instead, the
  2146     congruence is ignored.
  2147 
  2148 * Pure: New generic framework for extracting programs from constructive
  2149   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2150   as HOL/Extraction for some case studies.
  2151 
  2152 * Pure: The main goal of the proof state is no longer shown by default, only
  2153 the subgoals. This behaviour is controlled by a new flag.
  2154    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2155 (ML: Proof.show_main_goal).
  2156 
  2157 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2158 rules whose conclusion matches subgoal 1:
  2159       PG menu: Isabelle/Isar -> Show me -> matching rules
  2160 The rules are ordered by how closely they match the subgoal.
  2161 In particular, rules that solve a subgoal outright are displayed first
  2162 (or rather last, the way they are printed).
  2163 (ML: ProofGeneral.print_intros())
  2164 
  2165 * Pure: New flag trace_unify_fail causes unification to print
  2166 diagnostic information (PG: in trace buffer) when it fails. This is
  2167 useful for figuring out why single step proofs like rule, erule or
  2168 assumption failed.
  2169 
  2170 * Pure: Locale specifications now produce predicate definitions
  2171 according to the body of text (covering assumptions modulo local
  2172 definitions); predicate "loc_axioms" covers newly introduced text,
  2173 while "loc" is cumulative wrt. all included locale expressions; the
  2174 latter view is presented only on export into the global theory
  2175 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2176 on the old view without predicates;
  2177 
  2178 * Pure: predefined locales "var" and "struct" are useful for sharing
  2179 parameters (as in CASL, for example); just specify something like
  2180 ``var x + var y + struct M'' as import;
  2181 
  2182 * Pure: improved thms_containing: proper indexing of facts instead of
  2183 raw theorems; check validity of results wrt. current name space;
  2184 include local facts of proof configuration (also covers active
  2185 locales), cover fixed variables in index; may use "_" in term
  2186 specification; an optional limit for the number of printed facts may
  2187 be given (the default is 40);
  2188 
  2189 * Pure: disallow duplicate fact bindings within new-style theory files
  2190 (batch-mode only);
  2191 
  2192 * Provers: improved induct method: assumptions introduced by case
  2193 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2194 the goal statement); "foo" still refers to all facts collectively;
  2195 
  2196 * Provers: the function blast.overloaded has been removed: all constants
  2197 are regarded as potentially overloaded, which improves robustness in exchange
  2198 for slight decrease in efficiency;
  2199 
  2200 * Provers/linorder: New generic prover for transitivity reasoning over
  2201 linear orders.  Note: this prover is not efficient!
  2202 
  2203 * Isar: preview of problems to finish 'show' now produce an error
  2204 rather than just a warning (in interactive mode);
  2205 
  2206 
  2207 *** HOL ***
  2208 
  2209 * arith(_tac)
  2210 
  2211  - Produces a counter example if it cannot prove a goal.
  2212    Note that the counter example may be spurious if the goal is not a formula
  2213    of quantifier-free linear arithmetic.
  2214    In ProofGeneral the counter example appears in the trace buffer.
  2215 
  2216  - Knows about div k and mod k where k is a numeral of type nat or int.
  2217 
  2218  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2219    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2220    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2221 
  2222 * simp's arithmetic capabilities have been enhanced a bit: it now
  2223 takes ~= in premises into account (by performing a case split);
  2224 
  2225 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2226 are distributed over a sum of terms;
  2227 
  2228 * New tactic "trans_tac" and method "trans" instantiate
  2229 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2230 "<=", "<" and "=").
  2231 
  2232 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2233 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2234 
  2235 * 'typedef' command has new option "open" to suppress the set
  2236 definition;
  2237 
  2238 * functions Min and Max on finite sets have been introduced (theory
  2239 Finite_Set);
  2240 
  2241 * attribute [symmetric] now works for relations as well; it turns
  2242 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2243 
  2244 * induct over a !!-quantified statement (say !!x1..xn):
  2245   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2246 
  2247 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2248 %x. None. Warning: empty_def now refers to the previously hidden definition
  2249 of the empty set.
  2250 
  2251 * Algebra: formalization of classical algebra.  Intended as base for
  2252 any algebraic development in Isabelle.  Currently covers group theory
  2253 (up to Sylow's theorem) and ring theory (Universal Property of
  2254 Univariate Polynomials).  Contributions welcome;
  2255 
  2256 * GroupTheory: deleted, since its material has been moved to Algebra;
  2257 
  2258 * Complex: new directory of the complex numbers with numeric constants,
  2259 nonstandard complex numbers, and some complex analysis, standard and
  2260 nonstandard (Jacques Fleuriot);
  2261 
  2262 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2263 
  2264 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2265 Fleuriot);
  2266 
  2267 * Real/HahnBanach: updated and adapted to locales;
  2268 
  2269 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2270 Gray and Kramer);
  2271 
  2272 * UNITY: added the Meier-Sanders theory of progress sets;
  2273 
  2274 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2275 as abstract algorithms, instantiated to the JVM;
  2276 
  2277 * Bali: Java source language formalization. Type system, operational
  2278 semantics, axiomatic semantics. Supported language features:
  2279 classes, interfaces, objects,virtual methods, static methods,
  2280 static/instance fields, arrays, access modifiers, definite
  2281 assignment, exceptions.
  2282 
  2283 
  2284 *** ZF ***
  2285 
  2286 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2287 universe, etc.);
  2288 
  2289 * Main ZF: virtually all theories converted to new-style format;
  2290 
  2291 
  2292 *** ML ***
  2293 
  2294 * Pure: Tactic.prove provides sane interface for internal proofs;
  2295 omits the infamous "standard" operation, so this is more appropriate
  2296 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2297 
  2298 * Pure: improved error reporting of simprocs;
  2299 
  2300 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2301 up simprocs;
  2302 
  2303 
  2304 *** Document preparation ***
  2305 
  2306 * uses \par instead of \\ for line breaks in theory text. This may
  2307 shift some page breaks in large documents. To get the old behaviour
  2308 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2309 
  2310 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2311 other packages
  2312 
  2313 * \<euro> now needs package babel/greek instead of marvosym (which
  2314 broke \Rightarrow)
  2315 
  2316 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2317 textcomp package)
  2318 
  2319 
  2320 
  2321 New in Isabelle2002 (March 2002)
  2322 --------------------------------
  2323 
  2324 *** Document preparation ***
  2325 
  2326 * greatly simplified document preparation setup, including more
  2327 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2328 instructive isatool mkdir; users should basically be able to get
  2329 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2330 users may run a separate document processing stage manually like this:
  2331 "isatool usedir -D output HOL Test && isatool document Test/output";
  2332 
  2333 * theory dependency graph may now be incorporated into documents;
  2334 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2335 with \includegraphics of LaTeX;
  2336 
  2337 * proper spacing of consecutive markup elements, especially text
  2338 blocks after section headings;
  2339 
  2340 * support bold style (for single symbols only), input syntax is like
  2341 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2342 
  2343 * \<bullet> is now output as bold \cdot by default, which looks much
  2344 better in printed text;
  2345 
  2346 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2347 note that these symbols are currently unavailable in Proof General /
  2348 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2349 
  2350 * isatool latex no longer depends on changed TEXINPUTS, instead
  2351 isatool document copies the Isabelle style files to the target
  2352 location;
  2353 
  2354 
  2355 *** Isar ***
  2356 
  2357 * Pure/Provers: improved proof by cases and induction;
  2358   - 'case' command admits impromptu naming of parameters (such as
  2359     "case (Suc n)");
  2360   - 'induct' method divinates rule instantiation from the inductive
  2361     claim; no longer requires excessive ?P bindings for proper
  2362     instantiation of cases;
  2363   - 'induct' method properly enumerates all possibilities of set/type
  2364     rules; as a consequence facts may be also passed through *type*
  2365     rules without further ado;
  2366   - 'induct' method now derives symbolic cases from the *rulified*
  2367     rule (before it used to rulify cases stemming from the internal
  2368     atomized version); this means that the context of a non-atomic
  2369     statement becomes is included in the hypothesis, avoiding the
  2370     slightly cumbersome show "PROP ?case" form;
  2371   - 'induct' may now use elim-style induction rules without chaining
  2372     facts, using ``missing'' premises from the goal state; this allows
  2373     rules stemming from inductive sets to be applied in unstructured
  2374     scripts, while still benefitting from proper handling of non-atomic
  2375     statements; NB: major inductive premises need to be put first, all
  2376     the rest of the goal is passed through the induction;
  2377   - 'induct' proper support for mutual induction involving non-atomic
  2378     rule statements (uses the new concept of simultaneous goals, see
  2379     below);
  2380   - append all possible rule selections, but only use the first
  2381     success (no backtracking);
  2382   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2383   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2384   - added 'print_induct_rules' (covered by help item in recent Proof
  2385     General versions);
  2386   - moved induct/cases attributes to Pure, methods to Provers;
  2387   - generic method setup instantiated for FOL and HOL;
  2388 
  2389 * Pure: support multiple simultaneous goal statements, for example
  2390 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2391 meta-level mechanism, this acts as if several individual goals had
  2392 been stated separately; in particular common proof methods need to be
  2393 repeated in order to cover all claims; note that a single elimination
  2394 step is *not* sufficient to establish the two conjunctions, so this
  2395 fails:
  2396 
  2397   assume "A & B" then have A and B ..   (*".." fails*)
  2398 
  2399 better use "obtain" in situations as above; alternative refer to
  2400 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2401 
  2402 * Pure: proper integration with ``locales''; unlike the original
  2403 version by Florian Kammller, Isar locales package high-level proof
  2404 contexts rather than raw logical ones (e.g. we admit to include
  2405 attributes everywhere); operations on locales include merge and
  2406 rename; support for implicit arguments (``structures''); simultaneous
  2407 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2408 some examples;
  2409 
  2410 * Pure: the following commands have been ``localized'', supporting a
  2411 target locale specification "(in name)": 'lemma', 'theorem',
  2412 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2413 stored both within the locale and at the theory level (exported and
  2414 qualified by the locale name);
  2415 
  2416 * Pure: theory goals may now be specified in ``long'' form, with
  2417 ad-hoc contexts consisting of arbitrary locale elements. for example
  2418 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2419 definitions may be given, too); the result is a meta-level rule with
  2420 the context elements being discharged in the obvious way;
  2421 
  2422 * Pure: new proof command 'using' allows to augment currently used
  2423 facts after a goal statement ('using' is syntactically analogous to
  2424 'apply', but acts on the goal's facts only); this allows chained facts
  2425 to be separated into parts given before and after a claim, as in
  2426 ``from a and b have C using d and e <proof>'';
  2427 
  2428 * Pure: renamed "antecedent" case to "rule_context";
  2429 
  2430 * Pure: new 'judgment' command records explicit information about the
  2431 object-logic embedding (used by several tools internally); no longer
  2432 use hard-wired "Trueprop";
  2433 
  2434 * Pure: added 'corollary' command;
  2435 
  2436 * Pure: fixed 'token_translation' command;
  2437 
  2438 * Pure: removed obsolete 'exported' attribute;
  2439 
  2440 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2441 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2442 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2443 
  2444 * Pure: method 'atomize' presents local goal premises as object-level
  2445 statements (atomic meta-level propositions); setup controlled via
  2446 rewrite rules declarations of 'atomize' attribute; example
  2447 application: 'induct' method with proper rule statements in improper
  2448 proof *scripts*;
  2449 
  2450 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2451 now consider the syntactic context of assumptions, giving a better
  2452 chance to get type-inference of the arguments right (this is
  2453 especially important for locales);
  2454 
  2455 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2456 mode;
  2457 
  2458 * Pure/obtain: the formal conclusion "thesis", being marked as
  2459 ``internal'', may no longer be reference directly in the text;
  2460 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2461 situations;
  2462 
  2463 * Pure: generic 'sym' attribute which declares a rule both as pure
  2464 'elim?' and for the 'symmetric' operation;
  2465 
  2466 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2467 text; the fixed correlation with particular command syntax has been
  2468 discontinued;
  2469 
  2470 * Pure: new method 'rules' is particularly well-suited for proof
  2471 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2472 but often produces more compact proof terms with less detours;
  2473 
  2474 * Pure/Provers/classical: simplified integration with pure rule
  2475 attributes and methods; the classical "intro?/elim?/dest?"
  2476 declarations coincide with the pure ones; the "rule" method no longer
  2477 includes classically swapped intros; "intro" and "elim" methods no
  2478 longer pick rules from the context; also got rid of ML declarations
  2479 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2480 INCOMPATIBILITY;
  2481 
  2482 * Provers/classical: attribute 'swapped' produces classical inversions
  2483 of introduction rules;
  2484 
  2485 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2486 rules instead of full simplifier context; 'iff' attribute handles
  2487 conditional rules;
  2488 
  2489 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2490 
  2491 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2492 "(permissive)" option to recover old behavior;
  2493 
  2494 * HOL: 'inductive' no longer features separate (collective) attributes
  2495 for 'intros' (was found too confusing);
  2496 
  2497 * HOL: properly declared induction rules less_induct and
  2498 wf_induct_rule;
  2499 
  2500 
  2501 *** HOL ***
  2502 
  2503 * HOL: moved over to sane numeral syntax; the new policy is as
  2504 follows:
  2505 
  2506   - 0 and 1 are polymorphic constants, which are defined on any
  2507   numeric type (nat, int, real etc.);
  2508 
  2509   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2510   binary representation internally;
  2511 
  2512   - type nat has special constructor Suc, and generally prefers Suc 0
  2513   over 1::nat and Suc (Suc 0) over 2::nat;
  2514 
  2515 This change may cause significant problems of INCOMPATIBILITY; here
  2516 are some hints on converting existing sources:
  2517 
  2518   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2519   entities, so expressions involving "-" (unary or binary minus) need
  2520   to be spaced properly;
  2521 
  2522   - existing occurrences of "1" may need to be constraint "1::nat" or
  2523   even replaced by Suc 0; similar for old "2";
  2524 
  2525   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2526 
  2527   - remove all special provisions on numerals in proofs;
  2528 
  2529 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2530 representation (depends on bin_arith_simps in the default context);
  2531 
  2532 * HOL: symbolic syntax for x^2 (numeral 2);
  2533 
  2534 * HOL: the class of all HOL types is now called "type" rather than
  2535 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2536 in axclass/classes, instance/arities, and (usually rare) occurrences
  2537 in typings (of consts etc.); internally the class is called
  2538 "HOL.type", ML programs should refer to HOLogic.typeS;
  2539 
  2540 * HOL/record package improvements:
  2541   - new derived operations "fields" to build a partial record section,
  2542     "extend" to promote a fixed record to a record scheme, and
  2543     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2544     declared as simp by default;
  2545   - shared operations ("more", "fields", etc.) now need to be always
  2546     qualified) --- potential INCOMPATIBILITY;
  2547   - removed "make_scheme" operations (use "make" with "extend") --
  2548     INCOMPATIBILITY;
  2549   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2550   - provides cases/induct rules for use with corresponding Isar
  2551     methods (for concrete records, record schemes, concrete more
  2552     parts, and schematic more parts -- in that order);
  2553   - internal definitions directly based on a light-weight abstract
  2554     theory of product types over typedef rather than datatype;
  2555 
  2556 * HOL: generic code generator for generating executable ML code from
  2557 specifications; specific support for HOL constructs such as inductive
  2558 datatypes and sets, as well as recursive functions; can be invoked
  2559 via 'generate_code' theory section;
  2560 
  2561 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2562 
  2563 * HOL: consolidated and renamed several theories.  In particular:
  2564         Ord.thy has been absorbed into HOL.thy
  2565         String.thy has been absorbed into List.thy
  2566 
  2567 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2568 (beware of argument permutation!);
  2569 
  2570 * HOL: linorder_less_split superseded by linorder_cases;
  2571 
  2572 * HOL/List: "nodups" renamed to "distinct";
  2573 
  2574 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2575 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2576   - Ex_def has changed, now need to use some_eq_ex
  2577 
  2578 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2579 in this (rare) case use:
  2580 
  2581   delSWrapper "split_all_tac"
  2582   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2583 
  2584 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2585 MAY FAIL;
  2586 
  2587 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2588 Isabelle's type classes, ^ on functions and relations has too general
  2589 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2590 necessary to attach explicit type constraints;
  2591 
  2592 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2593 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2594 renamed accordingly (eg "compI" -> "rel_compI").
  2595 
  2596 * HOL: syntax translations now work properly with numerals and records
  2597 expressions;
  2598 
  2599 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2600 of "lam" -- INCOMPATIBILITY;
  2601 
  2602 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2603 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2604 renamed "Product_Type.unit";
  2605 
  2606 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2607 
  2608 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2609 the "cases" method);
  2610 
  2611 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2612 Florian Kammller);
  2613 
  2614 * HOL/IMP: updated and converted to new-style theory format; several
  2615 parts turned into readable document, with proper Isar proof texts and
  2616 some explanations (by Gerwin Klein);
  2617 
  2618 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2619 
  2620 * HOL-Hyperreal is now a logic image;
  2621 
  2622 
  2623 *** HOLCF ***
  2624 
  2625 * Isar: consts/constdefs supports mixfix syntax for continuous
  2626 operations;
  2627 
  2628 * Isar: domain package adapted to new-style theory format, e.g. see
  2629 HOLCF/ex/Dnat.thy;
  2630 
  2631 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2632 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2633 lift.induct_tac, always use UU instead of Undef;
  2634 
  2635 * HOLCF/IMP: updated and converted to new-style theory;
  2636 
  2637 
  2638 *** ZF ***
  2639 
  2640 * Isar: proper integration of logic-specific tools and packages,
  2641 including theory commands '(co)inductive', '(co)datatype',
  2642 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2643 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2644 
  2645 * theory Main no longer includes AC; for the Axiom of Choice, base
  2646 your theory on Main_ZFC;
  2647 
  2648 * the integer library now covers quotients and remainders, with many
  2649 laws relating division to addition, multiplication, etc.;
  2650 
  2651 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2652 typeless version of the formalism;
  2653 
  2654 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2655 format;
  2656 
  2657 * ZF/Induct: new directory for examples of inductive definitions,
  2658 including theory Multiset for multiset orderings; converted to
  2659 new-style theory format;
  2660 
  2661 * ZF: many new theorems about lists, ordinals, etc.;
  2662 
  2663 
  2664 *** General ***
  2665 
  2666 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2667 variable proof controls level of detail: 0 = no proofs (only oracle
  2668 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2669 also ref manual for further ML interfaces;
  2670 
  2671 * Pure/axclass: removed obsolete ML interface
  2672 goal_subclass/goal_arity;
  2673 
  2674 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2675 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2676 separate tokens, so expressions involving minus need to be spaced
  2677 properly;
  2678 
  2679 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2680 rather than "infixl" or "infixr";
  2681 
  2682 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2683 sort constraint specifications in type inference; e.g. "x::_::foo"
  2684 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2685 type variable);
  2686 
  2687 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2688 control output of nested => (types); the default behavior is
  2689 "type_brackets";
  2690 
  2691 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2692 tokens into AST constants;
  2693 
  2694 * Pure/syntax: prefer later declarations of translations and print
  2695 translation functions; potential INCOMPATIBILITY: need to reverse
  2696 multiple declarations for same syntax element constant;
  2697 
  2698 * Pure/show_hyps reset by default (in accordance to existing Isar
  2699 practice);
  2700 
  2701 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2702 addSafter;
  2703 
  2704 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2705 as well;
  2706 
  2707 * system: tested support for MacOS X; should be able to get Isabelle +
  2708 Proof General to work in a plain Terminal after installing Poly/ML
  2709 (e.g. from the Isabelle distribution area) and GNU bash alone
  2710 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2711 support requires further installations, e.g. from
  2712 http://fink.sourceforge.net/);
  2713 
  2714 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2715 
  2716 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2717 of 40 MB), cf. ML_OPTIONS;
  2718 
  2719 * system: Proof General keywords specification is now part of the
  2720 Isabelle distribution (see etc/isar-keywords.el);
  2721 
  2722 * system: support for persistent Proof General sessions (refrain from
  2723 outdating all loaded theories on startup); user may create writable
  2724 logic images like this: ``isabelle -q HOL Test'';
  2725 
  2726 * system: smart selection of Isabelle process versus Isabelle
  2727 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2728 run both "isabelle" and "Isabelle" even if file names are badly
  2729 damaged (executable inspects the case of the first letter of its own
  2730 name); added separate "isabelle-process" and "isabelle-interface";
  2731 
  2732 * system: refrain from any attempt at filtering input streams; no
  2733 longer support ``8bit'' encoding of old isabelle font, instead proper
  2734 iso-latin characters may now be used; the related isatools
  2735 "symbolinput" and "nonascii" have disappeared as well;
  2736 
  2737 * system: removed old "xterm" interface (the print modes "xterm" and
  2738 "xterm_color" are still available for direct use in a suitable
  2739 terminal);
  2740 
  2741 
  2742 
  2743 New in Isabelle99-2 (February 2001)
  2744 -----------------------------------
  2745 
  2746 *** Overview of INCOMPATIBILITIES ***
  2747 
  2748 * HOL: please note that theories in the Library and elsewhere often use the
  2749 new-style (Isar) format; to refer to their theorems in an ML script you must
  2750 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2751 
  2752 * HOL: inductive package no longer splits induction rule aggressively,
  2753 but only as far as specified by the introductions given; the old
  2754 format may be recovered via ML function complete_split_rule or attribute
  2755 'split_rule (complete)';
  2756 
  2757 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2758 gfp_Tarski to gfp_unfold;
  2759 
  2760 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2761 
  2762 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2763 relation); infix "^^" has been renamed "``"; infix "``" has been
  2764 renamed "`"; "univalent" has been renamed "single_valued";
  2765 
  2766 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2767 operation;
  2768 
  2769 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2770 
  2771 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2772 
  2773 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2774 consequence, it is no longer monotonic wrt. the local goal context
  2775 (which is now passed through the inductive cases);
  2776 
  2777 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2778 \<gg> to \<ggreater>;
  2779 
  2780 
  2781 *** Document preparation ***
  2782 
  2783 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2784 available: are "it" for near math-mode best-style output, "sl" for
  2785 slanted text style, and "tt" for plain type-writer; if no
  2786 \isabellestyle command is given, output is according to slanted
  2787 type-writer);
  2788 
  2789 * support sub/super scripts (for single symbols only), input syntax is
  2790 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2791 
  2792 * some more standard symbols; see Appendix A of the system manual for
  2793 the complete list of symbols defined in isabellesym.sty;
  2794 
  2795 * improved isabelle style files; more abstract symbol implementation
  2796 (should now use \isamath{...} and \isatext{...} in custom symbol
  2797 definitions);
  2798 
  2799 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2800 state; Note that presentation of goal states does not conform to
  2801 actual human-readable proof documents.  Please do not include goal
  2802 states into document output unless you really know what you are doing!
  2803 
  2804 * proper indentation of antiquoted output with proportional LaTeX
  2805 fonts;
  2806 
  2807 * no_document ML operator temporarily disables LaTeX document
  2808 generation;
  2809 
  2810 * isatool unsymbolize tunes sources for plain ASCII communication;
  2811 
  2812 
  2813 *** Isar ***
  2814 
  2815 * Pure: Isar now suffers initial goal statements to contain unbound
  2816 schematic variables (this does not conform to actual readable proof
  2817 documents, due to unpredictable outcome and non-compositional proof
  2818 checking); users who know what they are doing may use schematic goals
  2819 for Prolog-style synthesis of proven results;
  2820 
  2821 * Pure: assumption method (an implicit finishing) now handles actual
  2822 rules as well;
  2823 
  2824 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2825 initial goal, declare "that" only as Pure intro (only for single
  2826 steps); the "that" rule assumption may now be involved in implicit
  2827 finishing, thus ".." becomes a feasible for trivial obtains;
  2828 
  2829 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2830 instance proofs may be performed by "..";
  2831 
  2832 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2833 statements as well;
  2834 
  2835 * Pure: more robust selection of calculational rules;
  2836 
  2837 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2838 rule (as well as the assumption rule);
  2839 
  2840 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2841 lemmas, using the graph browser tool;
  2842 
  2843 * Pure: predict failure of "show" in interactive mode;
  2844 
  2845 * Pure: 'thms_containing' now takes actual terms as arguments;
  2846 
  2847 * HOL: improved method 'induct' --- now handles non-atomic goals
  2848 (potential INCOMPATIBILITY); tuned error handling;
  2849 
  2850 * HOL: cases and induct rules now provide explicit hints about the
  2851 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2852 any remaining facts are inserted into the goal verbatim;
  2853 
  2854 * HOL: local contexts (aka cases) may now contain term bindings as
  2855 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2856 the result to be shown in each case;
  2857 
  2858 * HOL: added 'recdef_tc' command;
  2859 
  2860 * isatool convert assists in eliminating legacy ML scripts;
  2861 
  2862 
  2863 *** HOL ***
  2864 
  2865 * HOL/Library: a collection of generic theories to be used together
  2866 with main HOL; the theory loader path already includes this directory
  2867 by default; the following existing theories have been moved here:
  2868 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2869 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2870 
  2871 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2872 modelling and verification task performed in Isabelle/HOL +
  2873 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2874 
  2875 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2876 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2877 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2878 'domain', this makes the theory consistent with mathematical
  2879 literature;
  2880 
  2881 * HOL basics: added overloaded operations "inverse" and "divide"
  2882 (infix "/"), syntax for generic "abs" operation, generic summation
  2883 operator \<Sum>;
  2884 
  2885 * HOL/typedef: simplified package, provide more useful rules (see also
  2886 HOL/subset.thy);
  2887 
  2888 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2889 now expressed as a proper nested rule (old-style tactic scripts may
  2890 require atomize_strip_tac to cope with non-atomic premises);
  2891 
  2892 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2893 to "split_conv" (old name still available for compatibility);
  2894 
  2895 * HOL: improved concrete syntax for strings (e.g. allows translation
  2896 rules with string literals);
  2897 
  2898 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2899  and Fleuriot's mechanization of analysis, including the transcendental
  2900  functions for the reals;
  2901 
  2902 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2903 
  2904 
  2905 *** CTT ***
  2906 
  2907 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2908 "lam" is displayed as TWO lambda-symbols
  2909 
  2910 * CTT: theory Main now available, containing everything (that is, Bool
  2911 and Arith);
  2912 
  2913 
  2914 *** General ***
  2915 
  2916 * Pure: the Simplifier has been implemented properly as a derived rule
  2917 outside of the actual kernel (at last!); the overall performance
  2918 penalty in practical applications is about 50%, while reliability of
  2919 the Isabelle inference kernel has been greatly improved;
  2920 
  2921 * print modes "brackets" and "no_brackets" control output of nested =>
  2922 (types) and ==> (props); the default behaviour is "brackets";
  2923 
  2924 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2925 as assumptions as well;
  2926 
  2927 * system: support Poly/ML 4.0;
  2928 
  2929 * system: isatool install handles KDE version 1 or 2;
  2930 
  2931 
  2932 
  2933 New in Isabelle99-1 (October 2000)
  2934 ----------------------------------
  2935 
  2936 *** Overview of INCOMPATIBILITIES ***
  2937 
  2938 * HOL: simplification of natural numbers is much changed; to partly
  2939 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2940 issue the following ML commands:
  2941 
  2942   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2943   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2944 
  2945 * HOL: simplification no longer dives into case-expressions; this is
  2946 controlled by "t.weak_case_cong" for each datatype t;
  2947 
  2948 * HOL: nat_less_induct renamed to less_induct;
  2949 
  2950 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2951 fixsome to patch .thy and .ML sources automatically;
  2952 
  2953   select_equality  -> some_equality
  2954   select_eq_Ex     -> some_eq_ex
  2955   selectI2EX       -> someI2_ex
  2956   selectI2         -> someI2
  2957   selectI          -> someI
  2958   select1_equality -> some1_equality
  2959   Eps_sym_eq       -> some_sym_eq_trivial
  2960   Eps_eq           -> some_eq_trivial
  2961 
  2962 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2963 
  2964 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2965 instead);
  2966 
  2967 * HOL: the recursion equations generated by 'recdef' are now called
  2968 f.simps instead of f.rules;
  2969 
  2970 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2971 
  2972 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2973 sometimes be needed;
  2974 
  2975 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2976 
  2977 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2978 
  2979 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2980 product is now "<*>" instead of "Times"; the lexicographic product is
  2981 now "<*lex*>" instead of "**";
  2982 
  2983 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2984 of main HOL, but was unused); better use HOL's datatype package;
  2985 
  2986 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2987 the old syntax may be recovered as follows:
  2988 
  2989   syntax (symbols)
  2990     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2991       (infixl "\\<oplus>" 100)
  2992 
  2993 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2994 
  2995 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2996 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2997 internally;
  2998 
  2999 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3000 changed from A/r to A//r;
  3001 
  3002 * ZF: new treatment of arithmetic (nat & int) may break some old
  3003 proofs;
  3004 
  3005 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3006 rulify -> rule_format, elimify -> elim_format, ...);
  3007 
  3008 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3009 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3010 should have to change intro!! to intro? only); replaced "delrule" by
  3011 "rule del";
  3012 
  3013 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3014 
  3015 * Provers: strengthened force_tac by using new first_best_tac;
  3016 
  3017 * LaTeX document preparation: several changes of isabelle.sty (see
  3018 lib/texinputs);
  3019 
  3020 
  3021 *** Document preparation ***
  3022 
  3023 * formal comments (text blocks etc.) in new-style theories may now
  3024 contain antiquotations of thm/prop/term/typ/text to be presented
  3025 according to latex print mode; concrete syntax is like this:
  3026 @{term[show_types] "f(x) = a + x"};
  3027 
  3028 * isatool mkdir provides easy setup of Isabelle session directories,
  3029 including proper document sources;
  3030 
  3031 * generated LaTeX sources are now deleted after successful run
  3032 (isatool document -c); may retain a copy somewhere else via -D option
  3033 of isatool usedir;
  3034 
  3035 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3036 style files, achieving self-contained LaTeX sources and simplifying
  3037 LaTeX debugging;
  3038 
  3039 * old-style theories now produce (crude) LaTeX output as well;
  3040 
  3041 * browser info session directories are now self-contained (may be put
  3042 on WWW server seperately); improved graphs of nested sessions; removed
  3043 graph for 'all sessions';
  3044 
  3045 * several improvements in isabelle style files; \isabellestyle{it}
  3046 produces fake math mode output; \isamarkupheader is now \section by
  3047 default; see lib/texinputs/isabelle.sty etc.;
  3048 
  3049 
  3050 *** Isar ***
  3051 
  3052 * Isar/Pure: local results and corresponding term bindings are now
  3053 subject to Hindley-Milner polymorphism (similar to ML); this
  3054 accommodates incremental type-inference very nicely;
  3055 
  3056 * Isar/Pure: new derived language element 'obtain' supports
  3057 generalized existence reasoning;
  3058 
  3059 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3060 support accumulation of results, without applying any rules yet;
  3061 useful to collect intermediate results without explicit name
  3062 references, and for use with transitivity rules with more than 2
  3063 premises;
  3064 
  3065 * Isar/Pure: scalable support for case-analysis type proofs: new
  3066 'case' language element refers to local contexts symbolically, as
  3067 produced by certain proof methods; internally, case names are attached
  3068 to theorems as "tags";
  3069 
  3070 * Isar/Pure: theory command 'hide' removes declarations from
  3071 class/type/const name spaces;
  3072 
  3073 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3074 indicate potential overloading;
  3075 
  3076 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3077 
  3078 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3079 "{a,b,c}" instead of {a,b,c};
  3080 
  3081 * Isar/Pure now provides its own version of intro/elim/dest
  3082 attributes; useful for building new logics, but beware of confusion
  3083 with the version in Provers/classical;
  3084 
  3085 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3086 case name 'antecedent';
  3087 
  3088 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3089 to the current context is now done automatically);
  3090 
  3091 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3092 for definining proof methods in ML;
  3093 
  3094 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3095 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3096 most cases, one should have to change intro!! to intro? only);
  3097 replaced "delrule" by "rule del";
  3098 
  3099 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3100 'symmetric' attribute (the latter supercedes [RS sym]);
  3101 
  3102 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3103 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3104 well (including splits);
  3105 
  3106 * Isar/Provers: Simplifier and Classical methods now support all kind
  3107 of modifiers used in the past, including 'cong', 'iff', etc.
  3108 
  3109 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3110 of Simplifier and Classical reasoner);
  3111 
  3112 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3113 now support named cases; major packages (inductive, datatype, primrec,
  3114 recdef) support case names and properly name parameters;
  3115 
  3116 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3117 monotonicity conditions are extracted to be proven at end of
  3118 calculations;
  3119 
  3120 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3121 method anyway;
  3122 
  3123 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3124 split_if split_if_asm; datatype package provides theorems foo.splits =
  3125 foo.split foo.split_asm for each datatype;
  3126 
  3127 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3128 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3129 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3130 use "(cases (simplified))" method in proper proof texts);
  3131 
  3132 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3133 
  3134 * Isar: names of theorems etc. may be natural numbers as well;
  3135 
  3136 * Isar: 'pr' command: optional arguments for goals_limit and
  3137 ProofContext.prems_limit; no longer prints theory contexts, but only
  3138 proof states;
  3139 
  3140 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3141 additional print modes to be specified; e.g. "pr(latex)" will print
  3142 proof state according to the Isabelle LaTeX style;
  3143 
  3144 * Isar: improved support for emulating tactic scripts, including proof
  3145 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3146 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3147 (for HOL datatypes);
  3148 
  3149 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3150 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3151 'proof method scripts' have to be in depth-first order;
  3152 
  3153 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3154 
  3155 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3156 should instead use individual commands for printing items
  3157 (print_commands, print_methods etc.);
  3158 
  3159 * Isar: added 'nothing' --- the empty list of theorems;
  3160 
  3161 
  3162 *** HOL ***
  3163 
  3164 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3165 corresponding virtual machine and a specification of its bytecode
  3166 verifier and a lightweight bytecode verifier, including proofs of
  3167 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3168 Cornelia Pusch (see also the homepage of project Bali at
  3169 http://isabelle.in.tum.de/Bali/);
  3170 
  3171 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3172 Clemens Ballarin;
  3173 
  3174 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3175 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3176 Rasmussen;
  3177 
  3178 * HOL/Lattice: fundamental concepts of lattice theory and order
  3179 structures, including duals, properties of bounds versus algebraic
  3180 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3181 Theorem for complete lattices etc.; may also serve as a demonstration
  3182 for abstract algebraic reasoning using axiomatic type classes, and
  3183 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3184 
  3185 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3186 von Oheimb;
  3187 
  3188 * HOL/IMPP: extension of IMP with local variables and mutually
  3189 recursive procedures, by David von Oheimb;
  3190 
  3191 * HOL/Lambda: converted into new-style theory and document;
  3192 
  3193 * HOL/ex/Multiquote: example of multiple nested quotations and
  3194 anti-quotations -- basically a generalized version of de-Bruijn
  3195 representation; very useful in avoiding lifting of operations;
  3196 
  3197 * HOL/record: added general record equality rule to simpset; fixed
  3198 select-update simplification procedure to handle extended records as
  3199 well; admit "r" as field name;
  3200 
  3201 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3202 other numeric types and also as the identity of groups, rings, etc.;
  3203 
  3204 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3205 Types nat and int belong to this axclass;
  3206 
  3207 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3208    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3209    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3210   two terms #m*u and #n*u are replaced by #(m+n)*u
  3211     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3212   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3213     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3214 
  3215 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3216 powerful prover for predicate logic but knows nothing of clasets; see
  3217 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3218 
  3219 * HOL: new version of "case_tac" subsumes both boolean case split and
  3220 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3221 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3222 
  3223 * HOL: simplification no longer dives into case-expressions: only the
  3224 selector expression is simplified, but not the remaining arms; to
  3225 enable full simplification of case-expressions for datatype t, you may
  3226 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3227 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3228 
  3229 * HOL/recdef: the recursion equations generated by 'recdef' for
  3230 function 'f' are now called f.simps instead of f.rules; if all
  3231 termination conditions are proved automatically, these simplification
  3232 rules are added to the simpset, as in primrec; rules may be named
  3233 individually as well, resulting in a separate list of theorems for
  3234 each equation;
  3235 
  3236 * HOL/While is a new theory that provides a while-combinator. It
  3237 permits the definition of tail-recursive functions without the
  3238 provision of a termination measure. The latter is necessary once the
  3239 invariant proof rule for while is applied.
  3240 
  3241 * HOL: new (overloaded) notation for the set of elements below/above
  3242 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3243 
  3244 * HOL: theorems impI, allI, ballI bound as "strip";
  3245 
  3246 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3247 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3248 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3249 
  3250 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3251 
  3252 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3253 main HOL, but was unused);
  3254 
  3255 * HOL: fewer consts declared as global (e.g. have to refer to
  3256 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3257 
  3258 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3259 in case of overlap with user translations (e.g. judgements over
  3260 tuples); (note that the underlying logical represenation is still
  3261 bogus);
  3262 
  3263 
  3264 *** ZF ***
  3265 
  3266 * ZF: simplification automatically cancels common terms in arithmetic
  3267 expressions over nat and int;
  3268 
  3269 * ZF: new treatment of nat to minimize type-checking: all operators
  3270 coerce their operands to a natural number using the function natify,
  3271 making the algebraic laws unconditional;
  3272 
  3273 * ZF: as above, for int: operators coerce their operands to an integer
  3274 using the function intify;
  3275 
  3276 * ZF: the integer library now contains many of the usual laws for the
  3277 orderings, including $<=, and monotonicity laws for $+ and $*;
  3278 
  3279 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3280 simplification;
  3281 
  3282 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3283 to the simplifier and classical reasoner simultaneously;
  3284 
  3285 
  3286 *** General ***
  3287 
  3288 * Provers: blast_tac now handles actual object-logic rules as
  3289 assumptions; note that auto_tac uses blast_tac internally as well;
  3290 
  3291 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3292 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3293 
  3294 * Provers: delrules now handles destruct rules as well (no longer need
  3295 explicit make_elim);
  3296 
  3297 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3298   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3299 use instead the strong form,
  3300   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3301 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3302 from destruct-rules;
  3303 
  3304 * Provers: Simplifier.easy_setup provides a fast path to basic
  3305 Simplifier setup for new object-logics;
  3306 
  3307 * Pure: AST translation rules no longer require constant head on LHS;
  3308 
  3309 * Pure: improved name spaces: ambiguous output is qualified; support
  3310 for hiding of names;
  3311 
  3312 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3313 XSYMBOL_HOME; no longer need to do manual configuration in most
  3314 situations;
  3315 
  3316 * system: compression of ML heaps images may now be controlled via -c
  3317 option of isabelle and isatool usedir (currently only observed by
  3318 Poly/ML);
  3319 
  3320 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3321 useful for remote X11);
  3322 
  3323 * system: provide TAGS file for Isabelle sources;
  3324 
  3325 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3326 order;
  3327 
  3328 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3329 timing flag supersedes proof_timing and Toplevel.trace;
  3330 
  3331 * ML: new combinators |>> and |>>> for incremental transformations
  3332 with secondary results (e.g. certain theory extensions):
  3333 
  3334 * ML: PureThy.add_defs gets additional argument to indicate potential
  3335 overloading (usually false);
  3336 
  3337 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3338 results;
  3339 
  3340 
  3341 
  3342 New in Isabelle99 (October 1999)
  3343 --------------------------------
  3344 
  3345 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3346 
  3347 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3348 are no longer simplified.  (This allows the simplifier to unfold recursive
  3349 functional programs.)  To restore the old behaviour, declare
  3350 
  3351     Delcongs [if_weak_cong];
  3352 
  3353 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3354 complement;
  3355 
  3356 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3357 
  3358 * HOL/datatype: mutual_induct_tac no longer exists --
  3359   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3360 
  3361 * HOL/typedef: fixed type inference for representing set; type
  3362 arguments now have to occur explicitly on the rhs as type constraints;
  3363 
  3364 * ZF: The con_defs part of an inductive definition may no longer refer
  3365 to constants declared in the same theory;
  3366 
  3367 * HOL, ZF: the function mk_cases, generated by the inductive
  3368 definition package, has lost an argument.  To simplify its result, it
  3369 uses the default simpset instead of a supplied list of theorems.
  3370 
  3371 * HOL/List: the constructors of type list are now Nil and Cons;
  3372 
  3373 * Simplifier: the type of the infix ML functions
  3374         setSSolver addSSolver setSolver addSolver
  3375 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3376 for packaging solvers. A solver is created via
  3377         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3378 where the string argument is only a comment.
  3379 
  3380 
  3381 *** Proof tools ***
  3382 
  3383 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3384 decision procedure for linear arithmetic. Currently it is used for
  3385 types `nat', `int', and `real' in HOL (see below); it can, should and
  3386 will be instantiated for other types and logics as well.
  3387 
  3388 * The simplifier now accepts rewrite rules with flexible heads, eg
  3389      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3390   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3391   matching.
  3392 
  3393 
  3394 *** General ***
  3395 
  3396 * New Isabelle/Isar subsystem provides an alternative to traditional
  3397 tactical theorem proving; together with the ProofGeneral/isar user
  3398 interface it offers an interactive environment for developing human
  3399 readable proof documents (Isar == Intelligible semi-automated
  3400 reasoning); for further information see isatool doc isar-ref,
  3401 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3402 
  3403 * improved and simplified presentation of theories: better HTML markup
  3404 (including colors), graph views in several sizes; isatool usedir now
  3405 provides a proper interface for user theories (via -P option); actual
  3406 document preparation based on (PDF)LaTeX is available as well (for
  3407 new-style theories only); see isatool doc system for more information;
  3408 
  3409 * native support for Proof General, both for classic Isabelle and
  3410 Isabelle/Isar;
  3411 
  3412 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3413 using the graph browser tool;
  3414 
  3415 * Isabelle manuals now also available as PDF;
  3416 
  3417 * theory loader rewritten from scratch (may not be fully
  3418 bug-compatible); old loadpath variable has been replaced by show_path,
  3419 add_path, del_path, reset_path functions; new operations such as
  3420 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3421 isatool doc ref);
  3422 
  3423 * improved isatool install: option -k creates KDE application icon,
  3424 option -p DIR installs standalone binaries;
  3425 
  3426 * added ML_PLATFORM setting (useful for cross-platform installations);
  3427 more robust handling of platform specific ML images for SML/NJ;
  3428 
  3429 * the settings environment is now statically scoped, i.e. it is never
  3430 created again in sub-processes invoked from isabelle, isatool, or
  3431 Isabelle;
  3432 
  3433 * path element specification '~~' refers to '$ISABELLE_HOME';
  3434 
  3435 * in locales, the "assumes" and "defines" parts may be omitted if
  3436 empty;
  3437 
  3438 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3439 long arrows);
  3440 
  3441 * new print_mode "HTML";
  3442 
  3443 * new flag show_tags controls display of tags of theorems (which are
  3444 basically just comments that may be attached by some tools);
  3445 
  3446 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3447 mode and goal output format:
  3448 
  3449 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3450 244c244
  3451 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3452 ---
  3453 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3454 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3455 181c181
  3456 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3457 ---
  3458 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3459 
  3460 * function bind_thms stores lists of theorems (cf. bind_thm);
  3461 
  3462 * new shorthand tactics ftac, eatac, datac, fatac;
  3463 
  3464 * qed (and friends) now accept "" as result name; in that case the
  3465 theorem is not stored, but proper checks and presentation of the
  3466 result still apply;
  3467 
  3468 * theorem database now also indexes constants "Trueprop", "all",
  3469 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3470 
  3471 
  3472 *** HOL ***
  3473 
  3474 ** HOL arithmetic **
  3475 
  3476 * There are now decision procedures for linear arithmetic over nat and
  3477 int:
  3478 
  3479 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3480 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3481 are treated as atomic; subformulae not involving type `nat' or `int'
  3482 are ignored; quantified subformulae are ignored unless they are
  3483 positive universal or negative existential. The tactic has to be
  3484 invoked by hand and can be a little bit slow. In particular, the
  3485 running time is exponential in the number of occurrences of `min' and
  3486 `max', and `-' on `nat'.
  3487 
  3488 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3489 (negated) (in)equalities among the premises and the conclusion into
  3490 account (i.e. no compound formulae) and does not know about `min' and
  3491 `max', and `-' on `nat'. It is fast and is used automatically by the
  3492 simplifier.
  3493 
  3494 NB: At the moment, these decision procedures do not cope with mixed
  3495 nat/int formulae where the two parts interact, such as `m < n ==>
  3496 int(m) < int(n)'.
  3497 
  3498 * HOL/Numeral provides a generic theory of numerals (encoded
  3499 efficiently as bit strings); setup for types nat/int/real is in place;
  3500 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3501 int, existing theories and proof scripts may require a few additional
  3502 type constraints;
  3503 
  3504 * integer division and remainder can now be performed on constant
  3505 arguments;
  3506 
  3507 * many properties of integer multiplication, division and remainder
  3508 are now available;
  3509 
  3510 * An interface to the Stanford Validity Checker (SVC) is available through the
  3511 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3512 are proved automatically.  SVC must be installed separately, and its results
  3513 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3514 invocation of the underlying oracle).  For SVC see
  3515   http://verify.stanford.edu/SVC
  3516 
  3517 * IsaMakefile: the HOL-Real target now builds an actual image;
  3518 
  3519 
  3520 ** HOL misc **
  3521 
  3522 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3523 (in Isabelle/Isar) -- by Gertrud Bauer;
  3524 
  3525 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3526 analysis for assembly languages with subtypes;
  3527 
  3528 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3529 -- avoids syntactic ambiguities and treats state, transition, and
  3530 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3531 changed syntax and (many) tactics;
  3532 
  3533 * HOL/inductive: Now also handles more general introduction rules such
  3534   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3535   theorems are now maintained within the theory (maintained via the
  3536   "mono" attribute);
  3537 
  3538 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3539   (using function types) such as
  3540 
  3541   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3542 
  3543 * HOL/record: record_simproc (part of the default simpset) takes care
  3544 of selectors applied to updated records; record_split_tac is no longer
  3545 part of the default claset; update_defs may now be removed from the
  3546 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3547 
  3548   claset_ref () := claset() addSWrapper record_split_wrapper;
  3549   Delsimprocs [record_simproc]
  3550 
  3551 * HOL/typedef: fixed type inference for representing set; type
  3552 arguments now have to occur explicitly on the rhs as type constraints;
  3553 
  3554 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3555 names rather than an ML expression;
  3556 
  3557 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3558 supplied later.  Program schemes can be defined, such as
  3559     "While B C s = (if B s then While B C (C s) else s)"
  3560 where the well-founded relation can be chosen after B and C have been given.
  3561 
  3562 * HOL/List: the constructors of type list are now Nil and Cons;
  3563 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3564 course, ML tools referring to List.list.op # etc. have to be adapted;
  3565 
  3566 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3567 disabled by default; run isabelle with option -m HOL to get back to
  3568 the original Gordon/HOL-style output;
  3569 
  3570 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3571 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3572 
  3573 * HOL basic syntax simplified (more orthogonal): all variants of
  3574 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3575 Eps operator is provided as well: "SOME x. P[x]";
  3576 
  3577 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3578 
  3579 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3580 thus available for user theories;
  3581 
  3582 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3583 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3584 time;
  3585 
  3586 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3587 several times and then mp;
  3588 
  3589 
  3590 *** LK ***
  3591 
  3592 * the notation <<...>> is now available as a notation for sequences of
  3593 formulas;
  3594 
  3595 * the simplifier is now installed
  3596 
  3597 * the axiom system has been generalized (thanks to Soren Heilmann)
  3598 
  3599 * the classical reasoner now has a default rule database
  3600 
  3601 
  3602 *** ZF ***
  3603 
  3604 * new primrec section allows primitive recursive functions to be given
  3605 directly (as in HOL) over datatypes and the natural numbers;
  3606 
  3607 * new tactics induct_tac and exhaust_tac for induction (or case
  3608 analysis) over datatypes and the natural numbers;
  3609 
  3610 * the datatype declaration of type T now defines the recursor T_rec;
  3611 
  3612 * simplification automatically does freeness reasoning for datatype
  3613 constructors;
  3614 
  3615 * automatic type-inference, with AddTCs command to insert new
  3616 type-checking rules;
  3617 
  3618 * datatype introduction rules are now added as Safe Introduction rules
  3619 to the claset;
  3620 
  3621 * the syntax "if P then x else y" is now available in addition to
  3622 if(P,x,y);
  3623 
  3624 
  3625 *** Internal programming interfaces ***
  3626 
  3627 * tuned simplifier trace output; new flag debug_simp;
  3628 
  3629 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3630 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3631 
  3632 * AxClass.axclass_tac lost the theory argument;
  3633 
  3634 * tuned current_goals_markers semantics: begin / end goal avoids
  3635 printing empty lines;
  3636 
  3637 * removed prs and prs_fn hook, which was broken because it did not
  3638 include \n in its semantics, forcing writeln to add one
  3639 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3640 string -> unit if you really want to output text without newline;
  3641 
  3642 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3643 plain output, interface builders may have to enable 'isabelle_font'
  3644 mode to get Isabelle font glyphs as before;
  3645 
  3646 * refined token_translation interface; INCOMPATIBILITY: output length
  3647 now of type real instead of int;
  3648 
  3649 * theory loader actions may be traced via new ThyInfo.add_hook
  3650 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3651 your own database of information attached to *whole* theories -- as
  3652 opposed to intra-theory data slots offered via TheoryDataFun;
  3653 
  3654 * proper handling of dangling sort hypotheses (at last!);
  3655 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3656 extra sort hypotheses that can be witnessed from the type signature;
  3657 the force_strip_shyps flag is gone, any remaining shyps are simply
  3658 left in the theorem (with a warning issued by strip_shyps_warning);
  3659 
  3660 
  3661 
  3662 New in Isabelle98-1 (October 1998)
  3663 ----------------------------------
  3664 
  3665 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3666 
  3667 * several changes of automated proof tools;
  3668 
  3669 * HOL: major changes to the inductive and datatype packages, including
  3670 some minor incompatibilities of theory syntax;
  3671 
  3672 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3673 called `inj_on';
  3674 
  3675 * HOL: removed duplicate thms in Arith:
  3676   less_imp_add_less  should be replaced by  trans_less_add1
  3677   le_imp_add_le      should be replaced by  trans_le_add1
  3678 
  3679 * HOL: unary minus is now overloaded (new type constraints may be
  3680 required);
  3681 
  3682 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3683 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3684 now taken as an integer constant.
  3685 
  3686 * Pure: ML function 'theory_of' renamed to 'theory';
  3687 
  3688 
  3689 *** Proof tools ***
  3690 
  3691 * Simplifier:
  3692   1. Asm_full_simp_tac is now more aggressive.
  3693      1. It will sometimes reorient premises if that increases their power to
  3694         simplify.
  3695      2. It does no longer proceed strictly from left to right but may also
  3696         rotate premises to achieve further simplification.
  3697      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3698      old Asm_full_simp_tac in that it does not rotate premises.
  3699   2. The simplifier now knows a little bit about nat-arithmetic.
  3700 
  3701 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3702 allows for selected deletion of wrappers, by introduction of names for
  3703 wrapper functionals.  This implies that addbefore, addSbefore,
  3704 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3705 and that adding two tactics with the same name overwrites the first
  3706 one (emitting a warning).
  3707   type wrapper = (int -> tactic) -> (int -> tactic)
  3708   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3709   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3710   delWrapper, delSWrapper: claset *  string            -> claset
  3711   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3712 
  3713 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3714 semantics; addbefore now affects only the unsafe part of step_tac
  3715 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3716 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3717 by Force_tac;
  3718 
  3719 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3720 compWrapper; added safe wrapper (and access functions for it);
  3721 
  3722 * HOL/split_all_tac is now much faster and fails if there is nothing
  3723 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3724 and the names of the automatically generated variables have changed.
  3725 split_all_tac has moved within claset() from unsafe wrappers to safe
  3726 wrappers, which means that !!-bound variables are split much more
  3727 aggressively, and safe_tac and clarify_tac now split such variables.
  3728 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3729 Note: the same holds for record_split_tac, which does the job of
  3730 split_all_tac for record fields.
  3731 
  3732 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3733 permanently to the default simpset using Addsplits just like
  3734 Addsimps. They can be removed via Delsplits just like
  3735 Delsimps. Lower-case versions are also available.
  3736 
  3737 * HOL/Simplifier: The rule split_if is now part of the default
  3738 simpset. This means that the simplifier will eliminate all occurrences
  3739 of if-then-else in the conclusion of a goal. To prevent this, you can
  3740 either remove split_if completely from the default simpset by
  3741 `Delsplits [split_if]' or remove it in a specific call of the
  3742 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3743 other case splitting rules to/from the default simpset: every datatype
  3744 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3745 t is the name of the datatype).
  3746 
  3747 * Classical reasoner / Simplifier combination: new force_tac (and
  3748 derivatives Force_tac, force) combines rewriting and classical
  3749 reasoning (and whatever other tools) similarly to auto_tac, but is
  3750 aimed to solve the given subgoal completely.
  3751 
  3752 
  3753 *** General ***
  3754 
  3755 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3756 and `goalw': the theory is no longer needed as an explicit argument -
  3757 the current theory context is used; assumptions are no longer returned
  3758 at the ML-level unless one of them starts with ==> or !!; it is
  3759 recommended to convert to these new commands using isatool fixgoal
  3760 (backup your sources first!);
  3761 
  3762 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3763 the current theory context, and 'theory' to lookup stored theories;
  3764 
  3765 * new theory section 'locale' for declaring constants, assumptions and
  3766 definitions that have local scope;
  3767 
  3768 * new theory section 'nonterminals' for purely syntactic types;
  3769 
  3770 * new theory section 'setup' for generic ML setup functions
  3771 (e.g. package initialization);
  3772 
  3773 * the distribution now includes Isabelle icons: see
  3774 lib/logo/isabelle-{small,tiny}.xpm;
  3775 
  3776 * isatool install - install binaries with absolute references to
  3777 ISABELLE_HOME/bin;
  3778 
  3779 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3780 
  3781 * print mode 'emacs' reserved for Isamode;
  3782 
  3783 * support multiple print (ast) translations per constant name;
  3784 
  3785 * theorems involving oracles are now printed with a suffixed [!];
  3786 
  3787 
  3788 *** HOL ***
  3789 
  3790 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3791 
  3792 * HOL/inductive package reorganized and improved: now supports mutual
  3793 definitions such as
  3794 
  3795   inductive EVEN ODD
  3796     intrs
  3797       null "0 : EVEN"
  3798       oddI "n : EVEN ==> Suc n : ODD"
  3799       evenI "n : ODD ==> Suc n : EVEN"
  3800 
  3801 new theorem list "elims" contains an elimination rule for each of the
  3802 recursive sets; inductive definitions now handle disjunctive premises
  3803 correctly (also ZF);
  3804 
  3805 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3806 "mutual_induct" no longer exists - the induction rule is always
  3807 contained in "induct";
  3808 
  3809 
  3810 * HOL/datatype package re-implemented and greatly improved: now
  3811 supports mutually recursive datatypes such as
  3812 
  3813   datatype
  3814     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3815             | SUM ('a aexp) ('a aexp)
  3816             | DIFF ('a aexp) ('a aexp)
  3817             | NUM 'a
  3818   and
  3819     'a bexp = LESS ('a aexp) ('a aexp)
  3820             | AND ('a bexp) ('a bexp)
  3821             | OR ('a bexp) ('a bexp)
  3822 
  3823 as well as indirectly recursive datatypes such as
  3824 
  3825   datatype
  3826     ('a, 'b) term = Var 'a
  3827                   | App 'b ((('a, 'b) term) list)
  3828 
  3829 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3830 induction on mutually / indirectly recursive datatypes.
  3831 
  3832 Primrec equations are now stored in theory and can be accessed via
  3833 <function_name>.simps.
  3834 
  3835 INCOMPATIBILITIES:
  3836 
  3837   - Theories using datatypes must now have theory Datatype as an
  3838     ancestor.
  3839   - The specific <typename>.induct_tac no longer exists - use the
  3840     generic induct_tac instead.
  3841   - natE has been renamed to nat.exhaust - use exhaust_tac
  3842     instead of res_inst_tac ... natE. Note that the variable
  3843     names in nat.exhaust differ from the names in natE, this
  3844     may cause some "fragile" proofs to fail.
  3845   - The theorems split_<typename>_case and split_<typename>_case_asm
  3846     have been renamed to <typename>.split and <typename>.split_asm.
  3847   - Since default sorts of type variables are now handled correctly,
  3848     some datatype definitions may have to be annotated with explicit
  3849     sort constraints.
  3850   - Primrec definitions no longer require function name and type
  3851     of recursive argument.
  3852 
  3853 Consider using isatool fixdatatype to adapt your theories and proof
  3854 scripts to the new package (backup your sources first!).
  3855 
  3856 
  3857 * HOL/record package: considerably improved implementation; now
  3858 includes concrete syntax for record types, terms, updates; theorems
  3859 for surjective pairing and splitting !!-bound record variables; proof
  3860 support is as follows:
  3861 
  3862   1) standard conversions (selectors or updates applied to record
  3863 constructor terms) are part of the standard simpset;
  3864 
  3865   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3866 made part of standard simpset and claset via addIffs;
  3867 
  3868   3) a tactic for record field splitting (record_split_tac) is part of
  3869 the standard claset (addSWrapper);
  3870 
  3871 To get a better idea about these rules you may retrieve them via
  3872 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3873 the name of your record type.
  3874 
  3875 The split tactic 3) conceptually simplifies by the following rule:
  3876 
  3877   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3878 
  3879 Thus any record variable that is bound by meta-all will automatically
  3880 blow up into some record constructor term, consequently the
  3881 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3882 solve record problems automatically.
  3883 
  3884 
  3885 * reorganized the main HOL image: HOL/Integ and String loaded by
  3886 default; theory Main includes everything;
  3887 
  3888 * automatic simplification of integer sums and comparisons, using cancellation;
  3889 
  3890 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3891 
  3892 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3893 
  3894 * many new identities for unions, intersections, set difference, etc.;
  3895 
  3896 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3897 called split_if, split_split, split_sum_case and split_nat_case (to go
  3898 with add/delsplits);
  3899 
  3900 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3901 (?x::unit) = (); this is made part of the default simpset, which COULD
  3902 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3903 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3904 unit_abs_eta_conv is added in order to counter the effect of
  3905 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3906 %u.f();
  3907 
  3908 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3909 makes more sense);
  3910 
  3911 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3912   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3913   disjointness reasoning but breaking a few old proofs.
  3914 
  3915 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3916 to 'converse' from 'inverse' (for compatibility with ZF and some
  3917 literature);
  3918 
  3919 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3920 the well-founded relation;
  3921 
  3922 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3923     Compl A.  The "Compl" syntax remains available as input syntax for this
  3924     release ONLY.
  3925 
  3926 * HOL/Update: new theory of function updates:
  3927     f(a:=b) == %x. if x=a then b else f x
  3928 may also be iterated as in f(a:=b,c:=d,...);
  3929 
  3930 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3931 
  3932 * HOL/List:
  3933   - new function list_update written xs[i:=v] that updates the i-th
  3934     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3935   - new function `upt' written [i..j(] which generates the list
  3936     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3937     bound write [i..j], which is a shorthand for [i..j+1(].
  3938   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3939 
  3940 * HOL/Arith:
  3941   - removed 'pred' (predecessor) function;
  3942   - generalized some theorems about n-1;
  3943   - many new laws about "div" and "mod";
  3944   - new laws about greatest common divisors (see theory ex/Primes);
  3945 
  3946 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3947 instead of "inverse";
  3948 
  3949 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3950   of the multiset ordering;
  3951 
  3952 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3953   (not included by default);
  3954 
  3955 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3956 
  3957 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3958   programs, i.e. different program variables may have different types.
  3959 
  3960 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3961   [previously, this check worked only if the rewrite rule was unconditional]
  3962   Now rew can involve either definitions or equalities (either == or =).
  3963 
  3964 
  3965 *** ZF ***
  3966 
  3967 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3968   only the theorems proved on ZF.ML;
  3969 
  3970 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3971   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3972   disjointness reasoning but breaking a few old proofs.
  3973 
  3974 * ZF/Update: new theory of function updates
  3975     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3976   may also be iterated as in f(a:=b,c:=d,...);
  3977 
  3978 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3979 
  3980 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3981   [previously, this check worked only if the rewrite rule was unconditional]
  3982   Now rew can involve either definitions or equalities (either == or =).
  3983 
  3984 * case_tac provided for compatibility with HOL
  3985     (like the old excluded_middle_tac, but with subgoals swapped)
  3986 
  3987 
  3988 *** Internal programming interfaces ***
  3989 
  3990 * Pure: several new basic modules made available for general use, see
  3991 also src/Pure/README;
  3992 
  3993 * improved the theory data mechanism to support encapsulation (data
  3994 kind name replaced by private Object.kind, acting as authorization
  3995 key); new type-safe user interface via functor TheoryDataFun; generic
  3996 print_data function becomes basically useless;
  3997 
  3998 * removed global_names compatibility flag -- all theory declarations
  3999 are qualified by default;
  4000 
  4001 * module Pure/Syntax now offers quote / antiquote translation
  4002 functions (useful for Hoare logic etc. with implicit dependencies);
  4003 see HOL/ex/Antiquote for an example use;
  4004 
  4005 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4006 cterm -> thm;
  4007 
  4008 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4009 subgoal;
  4010 
  4011 * Display.print_goals function moved to Locale.print_goals;
  4012 
  4013 * standard print function for goals supports current_goals_markers
  4014 variable for marking begin of proof, end of proof, start of goal; the
  4015 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4016 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4017 for example;
  4018 
  4019 
  4020 
  4021 New in Isabelle98 (January 1998)
  4022 --------------------------------
  4023 
  4024 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4025 
  4026 * changed lexical syntax of terms / types: dots made part of long
  4027 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4028 
  4029 * simpset (and claset) reference variable replaced by functions
  4030 simpset / simpset_ref;
  4031 
  4032 * no longer supports theory aliases (via merge) and non-trivial
  4033 implicit merge of thms' signatures;
  4034 
  4035 * most internal names of constants changed due to qualified names;
  4036 
  4037 * changed Pure/Sequence interface (see Pure/seq.ML);
  4038 
  4039 
  4040 *** General Changes ***
  4041 
  4042 * hierachically structured name spaces (for consts, types, axms, thms
  4043 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4044 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4045 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4046 long_names for fully qualified output names; NOTE: ML programs
  4047 (special tactics, packages etc.) referring to internal names may have
  4048 to be adapted to cope with fully qualified names; in case of severe
  4049 backward campatibility problems try setting 'global_names' at compile
  4050 time to have enrything declared within a flat name space; one may also
  4051 fine tune name declarations in theories via the 'global' and 'local'
  4052 section;
  4053 
  4054 * reimplemented the implicit simpset and claset using the new anytype
  4055 data filed in signatures; references simpset:simpset ref etc. are
  4056 replaced by functions simpset:unit->simpset and
  4057 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4058 to patch your ML files accordingly;
  4059 
  4060 * HTML output now includes theory graph data for display with Java
  4061 applet or isatool browser; data generated automatically via isatool
  4062 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4063 
  4064 * defs may now be conditional; improved rewrite_goals_tac to handle
  4065 conditional equations;
  4066 
  4067 * defs now admits additional type arguments, using TYPE('a) syntax;
  4068 
  4069 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4070 creates a new theory node; implicit merge of thms' signatures is
  4071 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4072 transfer:theory->thm->thm in (rare) cases;
  4073 
  4074 * improved handling of draft signatures / theories; draft thms (and
  4075 ctyps, cterms) are automatically promoted to real ones;
  4076 
  4077 * slightly changed interfaces for oracles: admit many per theory, named
  4078 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4079 
  4080 * print_goals: optional output of const types (set show_consts and
  4081 show_types);
  4082 
  4083 * improved output of warnings (###) and errors (***);
  4084 
  4085 * subgoal_tac displays a warning if the new subgoal has type variables;
  4086 
  4087 * removed old README and Makefiles;
  4088 
  4089 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4090 
  4091 * removed obsolete init_pps and init_database;
  4092 
  4093 * deleted the obsolete tactical STATE, which was declared by
  4094     fun STATE tacfun st = tacfun st st;
  4095 
  4096 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4097 (which abbreviates $HOME);
  4098 
  4099 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4100 use isatool fixseq to adapt your ML programs (this works for fully
  4101 qualified references to the Sequence structure only!);
  4102 
  4103 * use_thy no longer requires writable current directory; it always
  4104 reloads .ML *and* .thy file, if either one is out of date;
  4105 
  4106 
  4107 *** Classical Reasoner ***
  4108 
  4109 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4110 tactics that use classical reasoning to simplify a subgoal without
  4111 splitting it into several subgoals;
  4112 
  4113 * Safe_tac: like safe_tac but uses the default claset;
  4114 
  4115 
  4116 *** Simplifier ***
  4117 
  4118 * added simplification meta rules:
  4119     (asm_)(full_)simplify: simpset -> thm -> thm;
  4120 
  4121 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4122 logics (again);
  4123 
  4124 * added prems argument to simplification procedures;
  4125 
  4126 * HOL, FOL, ZF: added infix function `addsplits':
  4127   instead of `<simpset> setloop (split_tac <thms>)'
  4128   you can simply write `<simpset> addsplits <thms>'
  4129 
  4130 
  4131 *** Syntax ***
  4132 
  4133 * TYPE('a) syntax for type reflection terms;
  4134 
  4135 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4136 
  4137 * pretty printer: changed order of mixfix annotation preference (again!);
  4138 
  4139 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4140 
  4141 
  4142 *** HOL ***
  4143 
  4144 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4145   with `addloop' of the simplifier to faciliate case splitting in premises.
  4146 
  4147 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4148 
  4149 * HOL/Auth: new protocol proofs including some for the Internet
  4150   protocol TLS;
  4151 
  4152 * HOL/Map: new theory of `maps' a la VDM;
  4153 
  4154 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4155 cancelling out common nat summands from =, <, <= (in)equalities, or
  4156 differences; simplification procedures nat_cancel_factor for
  4157 cancelling common factor from =, <, <= (in)equalities over natural
  4158 sums; nat_cancel contains both kinds of procedures, it is installed by
  4159 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4160 
  4161 * HOL/simplifier: terms of the form
  4162   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4163   are rewritten to
  4164   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4165   and those of the form
  4166   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4167   are rewritten to
  4168   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4169 
  4170 * HOL/datatype
  4171   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4172 
  4173   P(t_case f1 ... fn x) =
  4174      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4175         ...
  4176        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4177      )
  4178 
  4179   and a theorem `split_t_case_asm' of the form
  4180 
  4181   P(t_case f1 ... fn x) =
  4182     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4183         ...
  4184        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4185      )
  4186   which can be added to a simpset via `addsplits'. The existing theorems
  4187   expand_list_case and expand_option_case have been renamed to
  4188   split_list_case and split_option_case.
  4189 
  4190 * HOL/Arithmetic:
  4191   - `pred n' is automatically converted to `n-1'.
  4192     Users are strongly encouraged not to use `pred' any longer,
  4193     because it will disappear altogether at some point.
  4194   - Users are strongly encouraged to write "0 < n" rather than
  4195     "n ~= 0". Theorems and proof tools have been modified towards this
  4196     `standard'.
  4197 
  4198 * HOL/Lists:
  4199   the function "set_of_list" has been renamed "set" (and its theorems too);
  4200   the function "nth" now takes its arguments in the reverse order and
  4201   has acquired the infix notation "!" as in "xs!n".
  4202 
  4203 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4204 
  4205 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4206   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4207 
  4208 * HOL/record: extensible records with schematic structural subtyping
  4209 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4210 still lacks various theorems and concrete record syntax;
  4211 
  4212 
  4213 *** HOLCF ***
  4214 
  4215 * removed "axioms" and "generated by" sections;
  4216 
  4217 * replaced "ops" section by extended "consts" section, which is capable of
  4218   handling the continuous function space "->" directly;
  4219 
  4220 * domain package:
  4221   . proves theorems immediately and stores them in the theory,
  4222   . creates hierachical name space,
  4223   . now uses normal mixfix annotations (instead of cinfix...),
  4224   . minor changes to some names and values (for consistency),
  4225   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4226   . separator between mutual domain defs: changed "," to "and",
  4227   . improved handling of sort constraints;  now they have to
  4228     appear on the left-hand side of the equations only;
  4229 
  4230 * fixed LAM <x,y,zs>.b syntax;
  4231 
  4232 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4233 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4234 
  4235 
  4236 *** FOL and ZF ***
  4237 
  4238 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4239   with `addloop' of the simplifier to faciliate case splitting in premises.
  4240 
  4241 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4242 in HOL, they strip ALL and --> from proved theorems;
  4243 
  4244 
  4245 
  4246 New in Isabelle94-8 (May 1997)
  4247 ------------------------------
  4248 
  4249 *** General Changes ***
  4250 
  4251 * new utilities to build / run / maintain Isabelle etc. (in parts
  4252 still somewhat experimental); old Makefiles etc. still functional;
  4253 
  4254 * new 'Isabelle System Manual';
  4255 
  4256 * INSTALL text, together with ./configure and ./build scripts;
  4257 
  4258 * reimplemented type inference for greater efficiency, better error
  4259 messages and clean internal interface;
  4260 
  4261 * prlim command for dealing with lots of subgoals (an easier way of
  4262 setting goals_limit);
  4263 
  4264 
  4265 *** Syntax ***
  4266 
  4267 * supports alternative (named) syntax tables (parser and pretty
  4268 printer); internal interface is provided by add_modesyntax(_i);
  4269 
  4270 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4271 be used in conjunction with the Isabelle symbol font; uses the
  4272 "symbols" syntax table;
  4273 
  4274 * added token_translation interface (may translate name tokens in
  4275 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4276 the current print_mode); IMPORTANT: user print translation functions
  4277 are responsible for marking newly introduced bounds
  4278 (Syntax.mark_boundT);
  4279 
  4280 * token translations for modes "xterm" and "xterm_color" that display
  4281 names in bold, underline etc. or colors (which requires a color
  4282 version of xterm);
  4283 
  4284 * infixes may now be declared with names independent of their syntax;
  4285 
  4286 * added typed_print_translation (like print_translation, but may
  4287 access type of constant);
  4288 
  4289 
  4290 *** Classical Reasoner ***
  4291 
  4292 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4293 some limitations.  Blast_tac...
  4294   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4295   + ignores elimination rules that don't have the correct format
  4296         (the conclusion MUST be a formula variable)
  4297   + ignores types, which can make HOL proofs fail
  4298   + rules must not require higher-order unification, e.g. apply_type in ZF
  4299     [message "Function Var's argument not a bound variable" relates to this]
  4300   + its proof strategy is more general but can actually be slower
  4301 
  4302 * substitution with equality assumptions no longer permutes other
  4303 assumptions;
  4304 
  4305 * minor changes in semantics of addafter (now called addaltern); renamed
  4306 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4307 (and access functions for it);
  4308 
  4309 * improved combination of classical reasoner and simplifier:
  4310   + functions for handling clasimpsets
  4311   + improvement of addss: now the simplifier is called _after_ the
  4312     safe steps.
  4313   + safe variant of addss called addSss: uses safe simplifications
  4314     _during_ the safe steps. It is more complete as it allows multiple
  4315     instantiations of unknowns (e.g. with slow_tac).
  4316 
  4317 *** Simplifier ***
  4318 
  4319 * added interface for simplification procedures (functions that
  4320 produce *proven* rewrite rules on the fly, depending on current
  4321 redex);
  4322 
  4323 * ordering on terms as parameter (used for ordered rewriting);
  4324 
  4325 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4326 
  4327 * the solver is now split into a safe and an unsafe part.
  4328 This should be invisible for the normal user, except that the
  4329 functions setsolver and addsolver have been renamed to setSolver and
  4330 addSolver; added safe_asm_full_simp_tac;
  4331 
  4332 
  4333 *** HOL ***
  4334 
  4335 * a generic induction tactic `induct_tac' which works for all datatypes and
  4336 also for type `nat';
  4337 
  4338 * a generic case distinction tactic `exhaust_tac' which works for all
  4339 datatypes and also for type `nat';
  4340 
  4341 * each datatype comes with a function `size';
  4342 
  4343 * patterns in case expressions allow tuple patterns as arguments to
  4344 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4345 
  4346 * primrec now also works with type nat;
  4347 
  4348 * recdef: a new declaration form, allows general recursive functions to be
  4349 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4350 
  4351 * the constant for negation has been renamed from "not" to "Not" to
  4352 harmonize with FOL, ZF, LK, etc.;
  4353 
  4354 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4355 infinite lists;
  4356 
  4357 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4358 
  4359 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4360 problems in commutative rings, using axiomatic type classes for + and *;
  4361 
  4362 * more examples in HOL/MiniML and HOL/Auth;
  4363 
  4364 * more default rewrite rules for quantifiers, union/intersection;
  4365 
  4366 * a new constant `arbitrary == @x.False';
  4367 
  4368 * HOLCF/IOA replaces old HOL/IOA;
  4369 
  4370 * HOLCF changes: derived all rules and arities
  4371   + axiomatic type classes instead of classes
  4372   + typedef instead of faking type definitions
  4373   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4374   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4375   + eliminated the types void, one, tr
  4376   + use unit lift and bool lift (with translations) instead of one and tr
  4377   + eliminated blift from Lift3.thy (use Def instead of blift)
  4378   all eliminated rules are derived as theorems --> no visible changes ;
  4379 
  4380 
  4381 *** ZF ***
  4382 
  4383 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4384 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4385 as ZF_cs addSIs [equalityI];
  4386 
  4387 
  4388 
  4389 New in Isabelle94-7 (November 96)
  4390 ---------------------------------
  4391 
  4392 * allowing negative levels (as offsets) in prlev and choplev;
  4393 
  4394 * super-linear speedup for large simplifications;
  4395 
  4396 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4397 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4398 FAIL); can suppress it using the command Delsimps (ex_simps @
  4399 all_simps); De Morgan laws are also now included, by default;
  4400 
  4401 * improved printing of ==>  :  ~:
  4402 
  4403 * new object-logic "Sequents" adds linear logic, while replacing LK
  4404 and Modal (thanks to Sara Kalvala);
  4405 
  4406 * HOL/Auth: correctness proofs for authentication protocols;
  4407 
  4408 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4409 examples on HOL/Auth);
  4410 
  4411 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4412 the rewriter and classical reasoner simultaneously;
  4413 
  4414 * function uresult no longer returns theorems in "standard" format;
  4415 regain previous version by: val uresult = standard o uresult;
  4416 
  4417 
  4418 
  4419 New in Isabelle94-6
  4420 -------------------
  4421 
  4422 * oracles -- these establish an interface between Isabelle and trusted
  4423 external reasoners, which may deliver results as theorems;
  4424 
  4425 * proof objects (in particular record all uses of oracles);
  4426 
  4427 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4428 
  4429 * "constdefs" section in theory files;
  4430 
  4431 * "primrec" section (HOL) no longer requires names;
  4432 
  4433 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4434 
  4435 
  4436 
  4437 New in Isabelle94-5
  4438 -------------------
  4439 
  4440 * reduced space requirements;
  4441 
  4442 * automatic HTML generation from theories;
  4443 
  4444 * theory files no longer require "..." (quotes) around most types;
  4445 
  4446 * new examples, including two proofs of the Church-Rosser theorem;
  4447 
  4448 * non-curried (1994) version of HOL is no longer distributed;
  4449 
  4450 
  4451 
  4452 New in Isabelle94-4
  4453 -------------------
  4454 
  4455 * greatly reduced space requirements;
  4456 
  4457 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4458 
  4459 * searchable theorem database (see the section "Retrieving theorems" on
  4460 page 8 of the Reference Manual);
  4461 
  4462 * new examples, including Grabczewski's monumental case study of the
  4463 Axiom of Choice;
  4464 
  4465 * The previous version of HOL renamed to Old_HOL;
  4466 
  4467 * The new version of HOL (previously called CHOL) uses a curried syntax
  4468 for functions.  Application looks like f a b instead of f(a,b);
  4469 
  4470 * Mutually recursive inductive definitions finally work in HOL;
  4471 
  4472 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4473 translates to the operator "split";
  4474 
  4475 
  4476 
  4477 New in Isabelle94-3
  4478 -------------------
  4479 
  4480 * new infix operator, addss, allowing the classical reasoner to
  4481 perform simplification at each step of its search.  Example:
  4482         fast_tac (cs addss ss)
  4483 
  4484 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4485 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4486 look like (a,b) instead of <a,b>;
  4487 
  4488 * PLEASE NOTE: CHOL will eventually replace HOL!
  4489 
  4490 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4491 It translates to the operator "split".  A new theory of integers is available;
  4492 
  4493 * In ZF, integer numerals now denote two's-complement binary integers.
  4494 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4495 
  4496 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4497 of the Axiom of Choice;
  4498 
  4499 
  4500 
  4501 New in Isabelle94-2
  4502 -------------------
  4503 
  4504 * Significantly faster resolution;
  4505 
  4506 * the different sections in a .thy file can now be mixed and repeated
  4507 freely;
  4508 
  4509 * Database of theorems for FOL, HOL and ZF.  New
  4510 commands including qed, qed_goal and bind_thm store theorems in the database.
  4511 
  4512 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4513 a given theory (thms_of), or find out what theory a theorem was proved in
  4514 (theory_of_thm);
  4515 
  4516 * Bugs fixed in the inductive definition and datatype packages;
  4517 
  4518 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4519 and HOL_dup_cs obsolete;
  4520 
  4521 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4522 have been removed;
  4523 
  4524 * Simpler definition of function space in ZF;
  4525 
  4526 * new results about cardinal and ordinal arithmetic in ZF;
  4527 
  4528 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4529 types;
  4530 
  4531 
  4532 $Id$