NEWS
author wenzelm
Tue Dec 05 00:42:36 2006 +0100 (2006-12-05)
changeset 21647 fccafa917a68
parent 21595 b5a642c4d085
child 21717 410ca6910f6f
permissions -rw-r--r--
* Pure: official theorem names and additional comments are now strictly separate.
     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 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   243 instead of "FOO ". This allows multiple binder declarations to coexist
   244 in the same context.  INCOMPATIBILITY.
   245 
   246 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   247 primitive that also works in a locale context (both for constants and
   248 fixed variables).  Type declaration and internal syntactic
   249 representation of given constants retrieved from the context.
   250 
   251 * Isar/locales: new derived specification elements 'axiomatization',
   252 'definition', 'abbreviation', which support type-inference, admit
   253 object-level specifications (equality, equivalence).  See also the
   254 isar-ref manual.  Examples:
   255 
   256   axiomatization
   257     eq  (infix "===" 50) where
   258     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   259 
   260   definition "f x y = x + y + 1"
   261   definition g where "g x = f x x"
   262 
   263   abbreviation
   264     neq  (infix "=!=" 50) where
   265     "x =!= y == ~ (x === y)"
   266 
   267 These specifications may be also used in a locale context.  Then the
   268 constants being introduced depend on certain fixed parameters, and the
   269 constant name is qualified by the locale base name.  An internal
   270 abbreviation takes care for convenient input and output, making the
   271 parameters implicit and using the original short name.  See also
   272 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   273 entities from a monomorphic theory.
   274 
   275 Presently, abbreviations are only available 'in' a target locale, but
   276 not inherited by general import expressions.  Also note that
   277 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   278 'translations' in common applications.
   279 
   280 Concrete syntax is attached to specified constants in internal form,
   281 independently of name spaces.  The parse tree representation is
   282 slightly different -- use 'notation' instead of raw 'syntax', and
   283 'translations' with explicit "CONST" markup to accommodate this.
   284 
   285 * Isar/locales: improved parameter handling:
   286 - use of locales "var" and "struct" no longer necessary;
   287 - parameter renamings are no longer required to be injective.
   288   This enables, for example, to define a locale for endomorphisms thus:
   289   locale endom = homom mult mult h.
   290 
   291 * Isar/locales: changed the way locales with predicates are defined.
   292 Instead of accumulating the specification, the imported expression is
   293 now an interpretation.
   294 INCOMPATIBILITY: different normal form of locale expressions.
   295 In particular, in interpretations of locales with predicates,
   296 goals repesenting already interpreted fragments are not removed
   297 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   298 
   299 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   300 backward reasoning on locales predicates.  The methods are aware of
   301 interpretations and discharge corresponding goals.  `intro_locales' is
   302 less aggressive then `unfold_locales' and does not unfold predicates to
   303 assumptions.
   304 
   305 * Isar/locales: the order in which locale fragments are accumulated
   306 has changed.  This enables to override declarations from fragments
   307 due to interpretations -- for example, unwanted simp rules.
   308 
   309 * Provers/induct: improved internal context management to support
   310 local fixes and defines on-the-fly.  Thus explicit meta-level
   311 connectives !! and ==> are rarely required anymore in inductive goals
   312 (using object-logic connectives for this purpose has been long
   313 obsolete anyway).  The subsequent proof patterns illustrate advanced
   314 techniques of natural induction; general datatypes and inductive sets
   315 work analogously (see also src/HOL/Lambda for realistic examples).
   316 
   317 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   318 parameters:
   319 
   320   lemma
   321     fixes n :: nat and x :: 'a
   322     assumes a: "A n x"
   323     shows "P n x"
   324     using a                     -- {* make induct insert fact a *}
   325   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   326     case 0
   327     show ?case sorry
   328   next
   329     case (Suc n)
   330     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   331     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   332     show ?case sorry
   333   qed
   334 
   335 (2) This is how to perform induction over ``expressions of a certain
   336 form'', using a locally defined inductive parameter n == "a x"
   337 together with strengthening (the latter is usually required to get
   338 sufficiently flexible induction hypotheses):
   339 
   340   lemma
   341     fixes a :: "'a => nat"
   342     assumes a: "A (a x)"
   343     shows "P (a x)"
   344     using a
   345   proof (induct n == "a x" arbitrary: x)
   346     ...
   347 
   348 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   349 particular technique.
   350 
   351 (3) This is how to perform existential reasoning ('obtains' or
   352 'obtain') by induction, while avoiding explicit object-logic
   353 encodings:
   354 
   355   lemma
   356     fixes n :: nat
   357     obtains x :: 'a where "P n x" and "Q n x"
   358   proof (induct n arbitrary: thesis)
   359     case 0
   360     obtain x where "P 0 x" and "Q 0 x" sorry
   361     then show thesis by (rule 0)
   362   next
   363     case (Suc n)
   364     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   365     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   366     then show thesis by (rule Suc.prems)
   367   qed
   368 
   369 Here the 'arbitrary: thesis' specification essentially modifies the
   370 scope of the formal thesis parameter, in order to the get the whole
   371 existence statement through the induction as expected.
   372 
   373 * Provers/induct: mutual induction rules are now specified as a list
   374 of rule sharing the same induction cases.  HOL packages usually
   375 provide foo_bar.inducts for mutually defined items foo and bar
   376 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   377 specify mutual induction rules differently, i.e. like this:
   378 
   379   (induct rule: foo_bar.inducts)
   380   (induct set: foo bar)
   381   (induct type: foo bar)
   382 
   383 The ML function ProjectRule.projections turns old-style rules into the
   384 new format.
   385 
   386 * Provers/induct: improved handling of simultaneous goals.  Instead of
   387 introducing object-level conjunction, the statement is now split into
   388 several conclusions, while the corresponding symbolic cases are
   389 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   390 explicitly.  For example:
   391 
   392   lemma
   393     fixes n :: nat
   394     shows "P n" and "Q n"
   395   proof (induct n)
   396     case 0 case 1
   397     show "P 0" sorry
   398   next
   399     case 0 case 2
   400     show "Q 0" sorry
   401   next
   402     case (Suc n) case 1
   403     note `P n` and `Q n`
   404     show "P (Suc n)" sorry
   405   next
   406     case (Suc n) case 2
   407     note `P n` and `Q n`
   408     show "Q (Suc n)" sorry
   409   qed
   410 
   411 The split into subcases may be deferred as follows -- this is
   412 particularly relevant for goal statements with local premises.
   413 
   414   lemma
   415     fixes n :: nat
   416     shows "A n ==> P n" and "B n ==> Q n"
   417   proof (induct n)
   418     case 0
   419     {
   420       case 1
   421       note `A 0`
   422       show "P 0" sorry
   423     next
   424       case 2
   425       note `B 0`
   426       show "Q 0" sorry
   427     }
   428   next
   429     case (Suc n)
   430     note `A n ==> P n` and `B n ==> Q n`
   431     {
   432       case 1
   433       note `A (Suc n)`
   434       show "P (Suc n)" sorry
   435     next
   436       case 2
   437       note `B (Suc n)`
   438       show "Q (Suc n)" sorry
   439     }
   440   qed
   441 
   442 If simultaneous goals are to be used with mutual rules, the statement
   443 needs to be structured carefully as a two-level conjunction, using
   444 lists of propositions separated by 'and':
   445 
   446   lemma
   447     shows "a : A ==> P1 a"
   448           "a : A ==> P2 a"
   449       and "b : B ==> Q1 b"
   450           "b : B ==> Q2 b"
   451           "b : B ==> Q3 b"
   452   proof (induct set: A B)
   453 
   454 * Provers/induct: support coinduction as well.  See
   455 src/HOL/Library/Coinductive_List.thy for various examples.
   456 
   457 * Attribute "symmetric" produces result with standardized schematic
   458 variables (index 0).  Potential INCOMPATIBILITY.
   459 
   460 * Simplifier: by default the simplifier trace only shows top level rewrites
   461 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   462 less danger of being flooded by the trace. The trace indicates where parts
   463 have been suppressed.
   464   
   465 * Provers/classical: removed obsolete classical version of elim_format
   466 attribute; classical elim/dest rules are now treated uniformly when
   467 manipulating the claset.
   468 
   469 * Provers/classical: stricter checks to ensure that supplied intro,
   470 dest and elim rules are well-formed; dest and elim rules must have at
   471 least one premise.
   472 
   473 * Provers/classical: attributes dest/elim/intro take an optional
   474 weight argument for the rule (just as the Pure versions).  Weights are
   475 ignored by automated tools, but determine the search order of single
   476 rule steps.
   477 
   478 * Syntax: input syntax now supports dummy variable binding "%_. b",
   479 where the body does not mention the bound variable.  Note that dummy
   480 patterns implicitly depend on their context of bounds, which makes
   481 "{_. _}" match any set comprehension as expected.  Potential
   482 INCOMPATIBILITY -- parse translations need to cope with syntactic
   483 constant "_idtdummy" in the binding position.
   484 
   485 * Syntax: removed obsolete syntactic constant "_K" and its associated
   486 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   487 for example "A -> B" => "Pi A (%_. B)".
   488 
   489 * Pure: 'class_deps' command visualizes the subclass relation, using
   490 the graph browser tool.
   491 
   492 * Pure: 'print_theory' now suppresses entities with internal name
   493 (trailing "_") by default; use '!' option for full details.
   494 
   495 
   496 *** HOL ***
   497 
   498 * New syntactic class "size"; overloaded constant "size" now
   499 has type "'a::size ==> bool"
   500 
   501 * Constants "Divides.op div", "Divides.op mod" and "Divides.op dvd" no named
   502   "Divides.div", "Divides.mod" and "Divides.dvd"
   503   INCOMPATIBILITY for ML code directly refering to constant names.
   504 
   505 * Replaced "auto_term" by the conceptually simpler method "relation",
   506 which just applies the instantiated termination rule with no further
   507 simplifications.
   508 INCOMPATIBILITY: 
   509 Replace 
   510         termination by (auto_term "MYREL")
   511 with 
   512         termination by (relation "MYREL") auto
   513 
   514 * Automated termination proofs "by lexicographic_order" are now
   515 included in the abbreviated function command "fun". No explicit
   516 "termination" command is necessary anymore.
   517 INCOMPATIBILITY: If a "fun"-definition cannot be proved terminating by
   518 a lexicographic size order, then the command fails. Use the expanded
   519 version "function" for these cases.
   520 
   521 * New method "lexicographic_order" automatically synthesizes
   522 termination relations as lexicographic combinations of size measures. 
   523 Usage for (function package) termination proofs:
   524 
   525 termination 
   526 by lexicographic_order
   527 
   528 * Records: generalised field-update to take a function on the field 
   529 rather than the new value: r(|A := x|) is translated to A_update (K x) r
   530 The K-combinator that is internally used is called K_record.
   531 INCOMPATIBILITY: Usage of the plain update functions has to be
   532 adapted.
   533  
   534 * axclass "semiring_0" now contains annihilation axioms 
   535 ("x * 0 = 0","0 * x = 0"), which are required for a semiring. Richer 
   536 structures do not inherit from semiring_0 anymore, because this property 
   537 is a theorem there, not an axiom.
   538 INCOMPATIBILITY: In instances of semiring_0, there is more to prove, but 
   539 this is mostly trivial.
   540 
   541 * axclass "recpower" was generalized to arbitrary monoids, not just 
   542 commutative semirings.
   543 INCOMPATIBILITY: If you use recpower and need commutativity or a semiring
   544 property, add the corresponding classes.
   545 
   546 * Locale Lattic_Locales.partial_order changed (to achieve consistency with
   547   axclass order):
   548   - moved to Orderings.partial_order
   549   - additional parameter ``less''
   550   INCOMPATIBILITY.
   551 
   552 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   553 INCOMPATIBILITY: translations containing list_all2 may go wrong. On Isar
   554 level, use abbreviations instead.
   555 
   556 * Constant "List.op mem" in List.thy now has proper name: "List.memberl"
   557 INCOMPATIBILITY: rarely occuring name references (e.g. ``List.op mem.simps'')
   558 require renaming (e.g. ``List.memberl.simps'').
   559 
   560 * Renamed constants in HOL.thy:
   561     0      ~> HOL.zero
   562     1      ~> HOL.one
   563 INCOMPATIBILITY: ML code directly refering to constant names may need adaption
   564 This in general only affects hand-written proof tactics, simprocs and so on.
   565 
   566 * New theory Code_Generator providing class 'eq',
   567 allowing for code generation with polymorphic equality.
   568 
   569 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has been
   570 abandoned in favour of plain 'int'. INCOMPATIBILITY -- Significant changes
   571 for setting up numeral syntax for types:
   572 
   573   - new constants Numeral.pred and Numeral.succ instead
   574       of former Numeral.bin_pred and Numeral.bin_succ.
   575   - Use integer operations instead of bin_add, bin_mult and so on.
   576   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   577   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   578 
   579 See HOL/Integ/IntArith.thy for an example setup.
   580 
   581 * New top level command 'normal_form' computes the normal form of a term
   582 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   583 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   584 because the functions are compiled to ML first.
   585 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   586 an identifier.
   587 
   588 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   589 25 like -->); output depends on the "iff" print_mode, the default is
   590 "A = B" (with priority 50).
   591 
   592 * Renamed constants in HOL.thy and Orderings.thy:
   593     op +   ~> HOL.plus
   594     op -   ~> HOL.minus
   595     uminus ~> HOL.uminus
   596     op *   ~> HOL.times
   597     op <   ~> Orderings.less
   598     op <=  ~> Orderings.less_eq
   599 
   600 Adaptions may be required in the following cases:
   601 
   602 a) User-defined constants using any of the names "plus", "minus", "times",
   603 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   604 may go wrong.
   605 INCOMPATIBILITY: use more specific names.
   606 
   607 b) Variables named "plus", "minus", "times", "less", "less_eq"
   608 INCOMPATIBILITY: use more specific names.
   609 
   610 c) Permutative equations (e.g. "a + b = b + a")
   611 Since the change of names also changes the order of terms, permutative
   612 rewrite rules may get applied in a different order. Experience shows that
   613 this is rarely the case (only two adaptions in the whole Isabelle
   614 distribution).
   615 INCOMPATIBILITY: rewrite proofs
   616 
   617 d) ML code directly refering to constant names
   618 This in general only affects hand-written proof tactics, simprocs and so on.
   619 INCOMPATIBILITY: grep your sourcecode and replace names.
   620 
   621 * Relations less (<) and less_eq (<=) are also available on type bool.
   622 Modified syntax to disallow nesting without explicit parentheses,
   623 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   624 
   625 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   626 
   627 * Relation composition operator "op O" now has precedence 75 and binds
   628 stronger than union and intersection. INCOMPATIBILITY.
   629 
   630 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   631   Use "{m..<n}" (and relatives) instead.
   632 
   633 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   634 "t = s" to False (by simproc "neq_simproc").  For backward
   635 compatibility this can be disabled by ML "reset use_neq_simproc".
   636 
   637 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   638 
   639 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   640 
   641 * Theorem setsum_mult renamed to setsum_right_distrib.
   642 
   643 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   644 'rule' method.
   645 
   646 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   647 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   648 "=" on type bool) are handled, variable names of the form "lit_<n>"
   649 are no longer reserved, significant speedup.
   650 
   651 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   652 still supported as well.
   653 
   654 * inductive and datatype: provide projections of mutual rules, bundled
   655 as foo_bar.inducts;
   656 
   657 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to Library.
   658 
   659 * Library: moved theory Accessible_Part to main HOL.
   660 
   661 * Library: added theory Coinductive_List of potentially infinite lists
   662 as greatest fixed-point.
   663 
   664 * Library: added theory AssocList which implements (finite) maps as
   665 association lists.
   666 
   667 * New proof method "evaluation" for efficiently solving a goal (i.e. a
   668 boolean expression) by compiling it to ML. The goal is "proved" (via
   669 the oracle "Evaluation") if it evaluates to True.
   670 
   671 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   672 also when invoked by the simplifier.  This results in the simplifier
   673 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   674 fast_arith_split_limit to 0 to obtain the old behavior.
   675 
   676 * Support for hex (0x20) and binary (0b1001) numerals. 
   677 
   678 * New method: reify eqs (t), where eqs are equations for an
   679 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   680 parameter, computes a term s::'b and a list xs::'a list and proves the
   681 theorem I xs s = t. This is also known as reification or quoting. The
   682 resulting theorem is applied to the subgoal to substitute t with I xs
   683 s.  If t is omitted, the subgoal itself is reified.
   684 
   685 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   686 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   687 where f is supposed to be a computable function (in the sense of code
   688 generattion). The method uses reify to compute s and xs as above then
   689 applies corr_thm and uses normalization by evaluation to "prove" f s =
   690 r and finally gets the theorem t = r, which is again applied to the
   691 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   692 
   693 * Reflection: Automatic refification now handels binding, an example
   694 is available in HOL/ex/ReflectionEx.thy
   695 
   696 
   697 *** HOL-Algebra ***
   698 
   699 * Formalisation of ideals and the quotient construction over rings.
   700 
   701 * Order and lattice theory no longer based on records.
   702 INCOMPATIBILITY.
   703 
   704 * Method algebra is now set up via an attribute.  For examples see
   705 CRing.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   706 of algebraic structures.
   707 
   708 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.
   709 
   710 
   711 *** HOL-Complex ***
   712 
   713 * Theory Real: new method ferrack implements quantifier elimination
   714 for linear arithmetic over the reals. The quantifier elimination
   715 feature is used only for decision, for compatibility with arith. This
   716 means a goal is either solved or left unchanged, no simplification.
   717 
   718 
   719 *** ML ***
   720 
   721 * Pure/table:
   722 
   723 Function `...tab.foldl` removed.
   724 INCOMPATIBILITY: use `...tabfold` instead
   725 
   726 * Pure/library:
   727 
   728 `gen_rem(s)` abandoned in favour of `remove` / `subtract`.
   729 INCOMPATIBILITY:
   730 rewrite "gen_rem eq (xs, x)" to "remove (eq o swap) x xs"
   731 rewrite "gen_rems eq (xs, ys)" to "subtract (eq o swap) ys xs"
   732 drop "swap" if "eq" is symmetric.
   733 
   734 * Pure/library:
   735 
   736 infixes `ins` `ins_string` `ins_int` have been abandoned in favour of `insert`.
   737 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"
   738 
   739 * Pure/General/susp.ML:
   740 
   741 New module for delayed evaluations.
   742 
   743 * Pure/library:
   744 
   745 Semantically identical functions "equal_list" and "eq_list" have been
   746 unified to "eq_list".
   747 
   748 * Pure/library:
   749 
   750   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   751   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   752 
   753 The semantics of "burrow" is: "take a function with *simulatanously*
   754 transforms a list of value, and apply it *simulatanously* to a list of
   755 list of values of the appropriate type". Confer this with "map" which
   756 would *not* apply its argument function simulatanously but in
   757 sequence. "fold_burrow" has an additional context.
   758 
   759 Both actually avoid the usage of "unflat" since they hide away
   760 "unflat" from the user.
   761 
   762 * Pure/library: functions map2 and fold2 with curried syntax for
   763 simultanous mapping and folding:
   764 
   765     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   766     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   767 
   768 * Pure/library: indexed lists - some functions in the Isabelle library
   769 treating lists over 'a as finite mappings from [0...n] to 'a have been
   770 given more convenient names and signatures reminiscent of similar
   771 functions for alists, tables, etc:
   772 
   773   val nth: 'a list -> int -> 'a 
   774   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   775   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   776 
   777 Note that fold_index starts counting at index 0, not 1 like foldln
   778 used to.
   779 
   780 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   781 
   782 * Pure/General/name_mangler.ML provides a functor for generic name
   783 mangling (bijective mapping from expression values to strings).
   784 
   785 * Pure/General/rat.ML implements rational numbers.
   786 
   787 * Pure/General/table.ML: the join operations now works via exceptions
   788 DUP/SAME instead of type option.  This is simpler in simple cases, and
   789 admits slightly more efficient complex applications.
   790 
   791 * Pure: datatype Context.generic joins theory/Proof.context and
   792 provides some facilities for code that works in either kind of
   793 context, notably GenericDataFun for uniform theory and proof data.
   794 
   795 * Pure: 'advanced' translation functions (parse_translation etc.) now
   796 use Context.generic instead of just theory.
   797 
   798 * Pure: simplified internal attribute type, which is now always
   799 Context.generic * thm -> Context.generic * thm.  Global (theory)
   800 vs. local (Proof.context) attributes have been discontinued, while
   801 minimizing code duplication.  Thm.rule_attribute and
   802 Thm.declaration_attribute build canonical attributes; see also
   803 structure Context for further operations on Context.generic, notably
   804 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   805 declarations and definitions.
   806 
   807 * Pure/kernel: consts certification ignores sort constraints given in
   808 signature declarations.  (This information is not relevant to the
   809 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   810 
   811 * Pure: axiomatic type classes are now purely definitional, with
   812 explicit proofs of class axioms and super class relations performed
   813 internally.  See Pure/axclass.ML for the main internal interfaces --
   814 notably AxClass.define_class supercedes AxClass.add_axclass, and
   815 AxClass.axiomatize_class/classrel/arity supercede
   816 Sign.add_classes/classrel/arities.
   817 
   818 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   819 global/local versions on theory vs. Proof.context have been
   820 discontinued; Attrib.syntax and Method.syntax have been adapted
   821 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   822 attributes, methods, etc.
   823 
   824 * Pure: several functions of signature "... -> theory -> theory * ..."
   825 have been reoriented to "... -> theory -> ... * theory" in order to
   826 allow natural usage in combination with the ||>, ||>>, |-> and
   827 fold_map combinators.
   828 
   829 * Pure: official theorem names (closed derivations) and additional
   830 comments (tags) are now strictly separate.  Name hints -- which are
   831 maintained as tags -- may be attached any time without affecting the
   832 derivation.
   833 
   834 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   835 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   836 achieve the old behaviour.
   837 
   838 * Pure: the "Goal" constant is now called "prop", supporting a
   839 slightly more general idea of ``protecting'' meta-level rule
   840 statements.
   841 
   842 * Pure: Logic.(un)varify only works in a global context, which is now
   843 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   844 Logic.legacy_(un)varify as temporary workaround.
   845 
   846 * Pure: structure Name provides scalable operations for generating
   847 internal variable names, notably Name.variants etc.  This replaces
   848 some popular functions from term.ML:
   849 
   850   Term.variant		->  Name.variant
   851   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   852   Term.invent_names	->  Name.invent_list
   853 
   854 Note that low-level renaming rarely occurs in new code -- operations
   855 from structure Variable are used instead (see below).
   856 
   857 * Pure: structure Variable provides fundamental operations for proper
   858 treatment of fixed/schematic variables in a context.  For example,
   859 Variable.import introduces fixes for schematics of given facts and
   860 Variable.export reverses the effect (up to renaming) -- this replaces
   861 various freeze_thaw operations.
   862 
   863 * Pure: structure Goal provides simple interfaces for
   864 init/conclude/finish and tactical prove operations (replacing former
   865 Tactic.prove).  Goal.prove is the canonical way to prove results
   866 within a given context; Goal.prove_global is a degraded version for
   867 theory level goals, including a global Drule.standard.  Note that
   868 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   869 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   870 in a locale context).
   871 
   872 * Isar: simplified treatment of user-level errors, using exception
   873 ERROR of string uniformly.  Function error now merely raises ERROR,
   874 without any side effect on output channels.  The Isar toplevel takes
   875 care of proper display of ERROR exceptions.  ML code may use plain
   876 handle/can/try; cat_error may be used to concatenate errors like this:
   877 
   878   ... handle ERROR msg => cat_error msg "..."
   879 
   880 Toplevel ML code (run directly or through the Isar toplevel) may be
   881 embedded into the Isar toplevel with exception display/debug like
   882 this:
   883 
   884   Isar.toplevel (fn () => ...)
   885 
   886 INCOMPATIBILITY, removed special transform_error facilities, removed
   887 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   888 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   889 -- use plain ERROR instead.
   890 
   891 * Isar: theory setup now has type (theory -> theory), instead of a
   892 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   893 
   894 * Isar: installed ML toplevel pretty printer for type Proof.context,
   895 subject to ProofContext.debug/verbose flags.
   896 
   897 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   898 theory before entering a proof state.  Transactions now always see a
   899 quasi-functional intermediate checkpoint, both in interactive and
   900 batch mode.
   901 
   902 * Simplifier: the simpset of a running simplification process now
   903 contains a proof context (cf. Simplifier.the_context), which is the
   904 very context that the initial simpset has been retrieved from (by
   905 simpset_of/local_simpset_of).  Consequently, all plug-in components
   906 (solver, looper etc.) may depend on arbitrary proof data.
   907 
   908 * Simplifier.inherit_context inherits the proof context (plus the
   909 local bounds) of the current simplification process; any simproc
   910 etc. that calls the Simplifier recursively should do this!  Removed
   911 former Simplifier.inherit_bounds, which is already included here --
   912 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   913 specify an explicit context using Simplifier.context/theory_context.
   914 
   915 * Simplifier/Classical Reasoner: more abstract interfaces
   916 change_simpset/claset for modifying the simpset/claset reference of a
   917 theory; raw versions simpset/claset_ref etc. have been discontinued --
   918 INCOMPATIBILITY.
   919 
   920 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   921 "Trueprop" etc.
   922 
   923 
   924 *** System ***
   925 
   926 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   927 locations -- now includes the Isabelle version identifier as well.
   928 This simplifies use of multiple Isabelle installations.
   929 
   930 * isabelle-process: option -S (secure mode) disables some critical
   931 operations, notably runtime compilation and evaluation of ML source
   932 code.
   933 
   934 
   935 New in Isabelle2005 (October 2005)
   936 ----------------------------------
   937 
   938 *** General ***
   939 
   940 * Theory headers: the new header syntax for Isar theories is
   941 
   942   theory <name>
   943   imports <theory1> ... <theoryN>
   944   uses <file1> ... <fileM>
   945   begin
   946 
   947 where the 'uses' part is optional.  The previous syntax
   948 
   949   theory <name> = <theory1> + ... + <theoryN>:
   950 
   951 will disappear in the next release.  Use isatool fixheaders to convert
   952 existing theory files.  Note that there is no change in ancient
   953 non-Isar theories now, but these will disappear soon.
   954 
   955 * Theory loader: parent theories can now also be referred to via
   956 relative and absolute paths.
   957 
   958 * Command 'find_theorems' searches for a list of criteria instead of a
   959 list of constants. Known criteria are: intro, elim, dest, name:string,
   960 simp:term, and any term. Criteria can be preceded by '-' to select
   961 theorems that do not match. Intro, elim, dest select theorems that
   962 match the current goal, name:s selects theorems whose fully qualified
   963 name contain s, and simp:term selects all simplification rules whose
   964 lhs match term.  Any other term is interpreted as pattern and selects
   965 all theorems matching the pattern. Available in ProofGeneral under
   966 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   967 
   968   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   969 
   970 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   971 matching the current goal as introduction rule and not having "HOL."
   972 in their name (i.e. not being defined in theory HOL).
   973 
   974 * Command 'thms_containing' has been discontinued in favour of
   975 'find_theorems'; INCOMPATIBILITY.
   976 
   977 * Communication with Proof General is now 8bit clean, which means that
   978 Unicode text in UTF-8 encoding may be used within theory texts (both
   979 formal and informal parts).  Cf. option -U of the Isabelle Proof
   980 General interface.  Here are some simple examples (cf. src/HOL/ex):
   981 
   982   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   983   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   984 
   985 * Improved efficiency of the Simplifier and, to a lesser degree, the
   986 Classical Reasoner.  Typical big applications run around 2 times
   987 faster.
   988 
   989 
   990 *** Document preparation ***
   991 
   992 * Commands 'display_drafts' and 'print_drafts' perform simple output
   993 of raw sources.  Only those symbols that do not require additional
   994 LaTeX packages (depending on comments in isabellesym.sty) are
   995 displayed properly, everything else is left verbatim.  isatool display
   996 and isatool print are used as front ends (these are subject to the
   997 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   998 
   999 * Command tags control specific markup of certain regions of text,
  1000 notably folding and hiding.  Predefined tags include "theory" (for
  1001 theory begin and end), "proof" for proof commands, and "ML" for
  1002 commands involving ML code; the additional tags "visible" and
  1003 "invisible" are unused by default.  Users may give explicit tag
  1004 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1005 interpretation of tags is determined by the LaTeX job during document
  1006 preparation: see option -V of isatool usedir, or options -n and -t of
  1007 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1008 \isadroptag.
  1009 
  1010 Several document versions may be produced at the same time via isatool
  1011 usedir (the generated index.html will link all of them).  Typical
  1012 specifications include ''-V document=theory,proof,ML'' to present
  1013 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1014 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1015 these parts without any formal replacement text.  The Isabelle site
  1016 default settings produce ''document'' and ''outline'' versions as
  1017 specified above.
  1018 
  1019 * Several new antiquotations:
  1020 
  1021   @{term_type term} prints a term with its type annotated;
  1022 
  1023   @{typeof term} prints the type of a term;
  1024 
  1025   @{const const} is the same as @{term const}, but checks that the
  1026   argument is a known logical constant;
  1027 
  1028   @{term_style style term} and @{thm_style style thm} print a term or
  1029   theorem applying a "style" to it
  1030 
  1031   @{ML text}
  1032 
  1033 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1034 definitions, equations, inequations etc., 'concl' printing only the
  1035 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1036 to print the specified premise.  TermStyle.add_style provides an ML
  1037 interface for introducing further styles.  See also the "LaTeX Sugar"
  1038 document practical applications.  The ML antiquotation prints
  1039 type-checked ML expressions verbatim.
  1040 
  1041 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1042 and 'text' support optional locale specification '(in loc)', which
  1043 specifies the default context for interpreting antiquotations.  For
  1044 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1045 
  1046 * Option 'locale=NAME' of antiquotations specifies an alternative
  1047 context interpreting the subsequent argument.  For example: @{thm
  1048 [locale=lattice] inf_assoc}.
  1049 
  1050 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1051 a proof context.
  1052 
  1053 * Proper output of antiquotations for theory commands involving a
  1054 proof context (such as 'locale' or 'theorem (in loc) ...').
  1055 
  1056 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1057 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1058 
  1059 * isatool usedir: new option -C (default true) controls whether option
  1060 -D should include a copy of the original document directory; -C false
  1061 prevents unwanted effects such as copying of administrative CVS data.
  1062 
  1063 
  1064 *** Pure ***
  1065 
  1066 * Considerably improved version of 'constdefs' command.  Now performs
  1067 automatic type-inference of declared constants; additional support for
  1068 local structure declarations (cf. locales and HOL records), see also
  1069 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1070 sequential dependencies of definitions within a single 'constdefs'
  1071 section; moreover, the declared name needs to be an identifier.  If
  1072 all fails, consider to fall back on 'consts' and 'defs' separately.
  1073 
  1074 * Improved indexed syntax and implicit structures.  First of all,
  1075 indexed syntax provides a notational device for subscripted
  1076 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1077 expressions.  Secondly, in a local context with structure
  1078 declarations, number indexes \<^sub>n or the empty index (default
  1079 number 1) refer to a certain fixed variable implicitly; option
  1080 show_structs controls printing of implicit structures.  Typical
  1081 applications of these concepts involve record types and locales.
  1082 
  1083 * New command 'no_syntax' removes grammar declarations (and
  1084 translations) resulting from the given syntax specification, which is
  1085 interpreted in the same manner as for the 'syntax' command.
  1086 
  1087 * 'Advanced' translation functions (parse_translation etc.) may depend
  1088 on the signature of the theory context being presently used for
  1089 parsing/printing, see also isar-ref manual.
  1090 
  1091 * Improved 'oracle' command provides a type-safe interface to turn an
  1092 ML expression of type theory -> T -> term into a primitive rule of
  1093 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1094 is already included here); see also FOL/ex/IffExample.thy;
  1095 INCOMPATIBILITY.
  1096 
  1097 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1098 before); "cI" is no longer bound, use "c.intro" instead.
  1099 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1100 axclasses vs. locales.
  1101 
  1102 * Improved internal renaming of symbolic identifiers -- attach primes
  1103 instead of base 26 numbers.
  1104 
  1105 * New flag show_question_marks controls printing of leading question
  1106 marks in schematic variable names.
  1107 
  1108 * In schematic variable names, *any* symbol following \<^isub> or
  1109 \<^isup> is now treated as part of the base name.  For example, the
  1110 following works without printing of awkward ".0" indexes:
  1111 
  1112   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1113     by simp
  1114 
  1115 * Inner syntax includes (*(*nested*) comments*).
  1116 
  1117 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1118 annotations as "(00...)".
  1119 
  1120 * Clear separation of logical types and nonterminals, where the latter
  1121 may only occur in 'syntax' specifications or type abbreviations.
  1122 Before that distinction was only partially implemented via type class
  1123 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1124 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1125 exotic syntax specifications may require further adaption
  1126 (e.g. Cube/Cube.thy).
  1127 
  1128 * Removed obsolete type class "logic", use the top sort {} instead.
  1129 Note that non-logical types should be declared as 'nonterminals'
  1130 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1131 specifications.
  1132 
  1133 * Attributes 'induct' and 'cases': type or set names may now be
  1134 locally fixed variables as well.
  1135 
  1136 * Simplifier: can now control the depth to which conditional rewriting
  1137 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1138 Limit.
  1139 
  1140 * Simplifier: simplification procedures may now take the current
  1141 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1142 interface), which is very useful for calling the Simplifier
  1143 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1144 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1145 low-level mk_simproc no longer applies Logic.varify internally, to
  1146 allow for use in a context of fixed variables.
  1147 
  1148 * thin_tac now works even if the assumption being deleted contains !!
  1149 or ==>.  More generally, erule now works even if the major premise of
  1150 the elimination rule contains !! or ==>.
  1151 
  1152 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1153 
  1154 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1155 from Pure, which contains all common declarations already.  Both
  1156 theories are defined via plain Isabelle/Isar .thy files.
  1157 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1158 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1159 use isatool fixcpure to adapt your theory and ML sources.
  1160 
  1161 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1162 selections of theorems in named facts via index ranges.
  1163 
  1164 * 'print_theorems': in theory mode, really print the difference
  1165 wrt. the last state (works for interactive theory development only),
  1166 in proof mode print all local facts (cf. 'print_facts');
  1167 
  1168 * 'hide': option '(open)' hides only base names.
  1169 
  1170 * More efficient treatment of intermediate checkpoints in interactive
  1171 theory development.
  1172 
  1173 * Code generator is now invoked via code_module (incremental code
  1174 generation) and code_library (modular code generation, ML structures
  1175 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1176 must be quoted when used as identifiers.
  1177 
  1178 * New 'value' command for reading, evaluating and printing terms using
  1179 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1180 quoted when used as identifier.
  1181 
  1182 
  1183 *** Locales ***
  1184 
  1185 * New commands for the interpretation of locale expressions in
  1186 theories (1), locales (2) and proof contexts (3).  These generate
  1187 proof obligations from the expression specification.  After the
  1188 obligations have been discharged, theorems of the expression are added
  1189 to the theory, target locale or proof context.  The synopsis of the
  1190 commands is a follows:
  1191 
  1192   (1) interpretation expr inst
  1193   (2) interpretation target < expr
  1194   (3) interpret expr inst
  1195 
  1196 Interpretation in theories and proof contexts require a parameter
  1197 instantiation of terms from the current context.  This is applied to
  1198 specifications and theorems of the interpreted expression.
  1199 Interpretation in locales only permits parameter renaming through the
  1200 locale expression.  Interpretation is smart in that interpretations
  1201 that are active already do not occur in proof obligations, neither are
  1202 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1203 inspect active interpretations of a particular locale.  For details,
  1204 see the Isar Reference manual.  Examples can be found in
  1205 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1206 
  1207 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1208 'interpret' instead.
  1209 
  1210 * New context element 'constrains' for adding type constraints to
  1211 parameters.
  1212 
  1213 * Context expressions: renaming of parameters with syntax
  1214 redeclaration.
  1215 
  1216 * Locale declaration: 'includes' disallowed.
  1217 
  1218 * Proper static binding of attribute syntax -- i.e. types / terms /
  1219 facts mentioned as arguments are always those of the locale definition
  1220 context, independently of the context of later invocations.  Moreover,
  1221 locale operations (renaming and type / term instantiation) are applied
  1222 to attribute arguments as expected.
  1223 
  1224 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1225 actual attributes; rare situations may require Attrib.attribute to
  1226 embed those attributes into Attrib.src that lack concrete syntax.
  1227 Attribute implementations need to cooperate properly with the static
  1228 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1229 Attrib.XXX_thm etc. already do the right thing without further
  1230 intervention.  Only unusual applications -- such as "where" or "of"
  1231 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1232 on the context and the facts involved -- may have to assign parsed
  1233 values to argument tokens explicitly.
  1234 
  1235 * Changed parameter management in theorem generation for long goal
  1236 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1237 theorem statement in rare situations.
  1238 
  1239 * Locale inspection command 'print_locale' omits notes elements.  Use
  1240 'print_locale!' to have them included in the output.
  1241 
  1242 
  1243 *** Provers ***
  1244 
  1245 * Provers/hypsubst.ML: improved version of the subst method, for
  1246 single-step rewriting: it now works in bound variable contexts. New is
  1247 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1248 rewrite a different subterm than the original subst method, which is
  1249 still available as 'simplesubst'.
  1250 
  1251 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1252 and quasi orders.
  1253 
  1254 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1255 reflexive-transitive closure of relations.
  1256 
  1257 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1258 limit (previously hard-coded with a value of 20) user-definable.
  1259 
  1260 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1261 is peformed already.  Object-logics merely need to finish their
  1262 initial simpset configuration as before.  INCOMPATIBILITY.
  1263 
  1264 
  1265 *** HOL ***
  1266 
  1267 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1268 
  1269   syntax (epsilon)
  1270     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1271 
  1272 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1273 and x-symbol; use option '-m epsilon' to get it actually printed.
  1274 Moreover, the mathematically important symbolic identifier \<epsilon>
  1275 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1276 
  1277 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1278 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1279 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1280 support corresponding Isar calculations.
  1281 
  1282 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1283 instead of ":".
  1284 
  1285 * theory SetInterval: changed the syntax for open intervals:
  1286 
  1287   Old       New
  1288   {..n(}    {..<n}
  1289   {)n..}    {n<..}
  1290   {m..n(}   {m..<n}
  1291   {)m..n}   {m<..n}
  1292   {)m..n(}  {m<..<n}
  1293 
  1294 The old syntax is still supported but will disappear in the next
  1295 release.  For conversion use the following Emacs search and replace
  1296 patterns (these are not perfect but work quite well):
  1297 
  1298   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1299   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1300 
  1301 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1302 equalities in commutative rings; method 'algebra' provides a generic
  1303 interface.
  1304 
  1305 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1306 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1307 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1308 be a tuple pattern.
  1309 
  1310 Some new syntax forms are available:
  1311 
  1312   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1313   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1314   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1315   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1316 
  1317 The latter form "\<Sum>x < k. e" used to be based on a separate
  1318 function "Summation", which has been discontinued.
  1319 
  1320 * theory Finite_Set: in structured induction proofs, the insert case
  1321 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1322 (insert F x)'.
  1323 
  1324 * The 'refute' command has been extended to support a much larger
  1325 fragment of HOL, including axiomatic type classes, constdefs and
  1326 typedefs, inductive datatypes and recursion.
  1327 
  1328 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1329 Requires zChaff with proof generation to be installed.  See
  1330 HOL/ex/SAT_Examples.thy for examples.
  1331 
  1332 * Datatype induction via method 'induct' now preserves the name of the
  1333 induction variable. For example, when proving P(xs::'a list) by
  1334 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1335 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1336 in unstructured proof scripts.
  1337 
  1338 * Reworked implementation of records.  Improved scalability for
  1339 records with many fields, avoiding performance problems for type
  1340 inference. Records are no longer composed of nested field types, but
  1341 of nested extension types. Therefore the record type only grows linear
  1342 in the number of extensions and not in the number of fields.  The
  1343 top-level (users) view on records is preserved.  Potential
  1344 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1345 old record representation. The type generated for a record is called
  1346 <record_name>_ext_type.
  1347 
  1348 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1349 proofs triggered by a record definition or a simproc (if
  1350 quick_and_dirty is enabled).  Definitions of large records can take
  1351 quite long.
  1352 
  1353 New simproc record_upd_simproc for simplification of multiple record
  1354 updates enabled by default.  Moreover, trivial updates are also
  1355 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1356 occasionally, since simplification is more powerful by default.
  1357 
  1358 * typedef: proper support for polymorphic sets, which contain extra
  1359 type-variables in the term.
  1360 
  1361 * Simplifier: automatically reasons about transitivity chains
  1362 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1363 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1364 old proofs break occasionally as simplification may now solve more
  1365 goals than previously.
  1366 
  1367 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1368 present.  Works for all partial orders (class "order"), in particular
  1369 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1370 just like y <= x.
  1371 
  1372 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1373 bound variable or a constant then the let is unfolded.  Otherwise
  1374 first a is simplified to b, and then f b is simplified to g. If
  1375 possible we abstract b from g arriving at "let x = b in h x",
  1376 otherwise we unfold the let and arrive at g.  The simproc can be
  1377 enabled/disabled by the reference use_let_simproc.  Potential
  1378 INCOMPATIBILITY since simplification is more powerful by default.
  1379 
  1380 * Classical reasoning: the meson method now accepts theorems as arguments.
  1381 
  1382 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1383 jobs to provide advice on the provability of subgoals.
  1384 
  1385 * Theory OrderedGroup and Ring_and_Field: various additions and
  1386 improvements to faciliate calculations involving equalities and
  1387 inequalities.
  1388 
  1389 The following theorems have been eliminated or modified
  1390 (INCOMPATIBILITY):
  1391 
  1392   abs_eq             now named abs_of_nonneg
  1393   abs_of_ge_0        now named abs_of_nonneg
  1394   abs_minus_eq       now named abs_of_nonpos
  1395   imp_abs_id         now named abs_of_nonneg
  1396   imp_abs_neg_id     now named abs_of_nonpos
  1397   mult_pos           now named mult_pos_pos
  1398   mult_pos_le        now named mult_nonneg_nonneg
  1399   mult_pos_neg_le    now named mult_nonneg_nonpos
  1400   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1401   mult_neg           now named mult_neg_neg
  1402   mult_neg_le        now named mult_nonpos_nonpos
  1403 
  1404 * Theory Parity: added rules for simplifying exponents.
  1405 
  1406 * Theory List:
  1407 
  1408 The following theorems have been eliminated or modified
  1409 (INCOMPATIBILITY):
  1410 
  1411   list_all_Nil       now named list_all.simps(1)
  1412   list_all_Cons      now named list_all.simps(2)
  1413   list_all_conv      now named list_all_iff
  1414   set_mem_eq         now named mem_iff
  1415 
  1416 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1417 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1418 
  1419 
  1420 *** HOL-Complex ***
  1421 
  1422 * Theory RealDef: better support for embedding natural numbers and
  1423 integers in the reals.
  1424 
  1425 The following theorems have been eliminated or modified
  1426 (INCOMPATIBILITY):
  1427 
  1428   exp_ge_add_one_self  now requires no hypotheses
  1429   real_of_int_add      reversed direction of equality (use [symmetric])
  1430   real_of_int_minus    reversed direction of equality (use [symmetric])
  1431   real_of_int_diff     reversed direction of equality (use [symmetric])
  1432   real_of_int_mult     reversed direction of equality (use [symmetric])
  1433 
  1434 * Theory RComplete: expanded support for floor and ceiling functions.
  1435 
  1436 * Theory Ln is new, with properties of the natural logarithm
  1437 
  1438 * Hyperreal: There is a new type constructor "star" for making
  1439 nonstandard types.  The old type names are now type synonyms:
  1440 
  1441   hypreal = real star
  1442   hypnat = nat star
  1443   hcomplex = complex star
  1444 
  1445 * Hyperreal: Many groups of similarly-defined constants have been
  1446 replaced by polymorphic versions (INCOMPATIBILITY):
  1447 
  1448   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1449 
  1450   starset      <-- starsetNat, starsetC
  1451   *s*          <-- *sNat*, *sc*
  1452   starset_n    <-- starsetNat_n, starsetC_n
  1453   *sn*         <-- *sNatn*, *scn*
  1454   InternalSets <-- InternalNatSets, InternalCSets
  1455 
  1456   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1457   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1458   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1459   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1460   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1461 
  1462 * Hyperreal: Many type-specific theorems have been removed in favor of
  1463 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1464 
  1465   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1466   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1467   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1468   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1469   right_minus <-- hypreal_add_minus
  1470   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1471   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1472   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1473   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1474   mult_1_right <-- hcomplex_mult_one_right
  1475   mult_zero_left <-- hcomplex_mult_zero_left
  1476   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1477   right_distrib <-- hypnat_add_mult_distrib2
  1478   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1479   right_inverse <-- hypreal_mult_inverse
  1480   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1481   order_refl <-- {hypreal,hypnat}_le_refl
  1482   order_trans <-- {hypreal,hypnat}_le_trans
  1483   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1484   order_less_le <-- {hypreal,hypnat}_less_le
  1485   linorder_linear <-- {hypreal,hypnat}_le_linear
  1486   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1487   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1488   add_nonneg_nonneg <-- hypreal_le_add_order
  1489 
  1490 * Hyperreal: Separate theorems having to do with type-specific
  1491 versions of constants have been merged into theorems that apply to the
  1492 new polymorphic constants (INCOMPATIBILITY):
  1493 
  1494   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1495   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1496   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1497   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1498   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1499   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1500   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1501   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1502   STAR_diff <-- {STAR,STARC}_diff
  1503   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1504     STARC_hcomplex_of_complex}_image_subset
  1505   starset_n_Un <-- starset{Nat,C}_n_Un
  1506   starset_n_Int <-- starset{Nat,C}_n_Int
  1507   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1508   starset_n_diff <-- starset{Nat,C}_n_diff
  1509   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1510   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1511   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1512   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1513   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1514   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1515   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1516   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1517   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1518   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1519   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1520   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1521   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1522   starfun_diff <-- starfun{C,RC,CR}_diff
  1523   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1524   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1525   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1526   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1527   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1528   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1529   starfun_Id <-- starfunC_Id
  1530   starfun_approx <-- starfun{Nat,CR}_approx
  1531   starfun_capprox <-- starfun{C,RC}_capprox
  1532   starfun_abs <-- starfunNat_rabs
  1533   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1534   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1535   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1536   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1537   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1538   starfun_add_approx <-- starfunCR_add_approx
  1539   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1540   starfun_divide <-- starfun{C,CR,RC}_divide
  1541   starfun_n <-- starfun{Nat,C}_n
  1542   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1543   starfun_n_add <-- starfun{Nat,C}_n_add
  1544   starfun_n_add_minus <-- starfunNat_n_add_minus
  1545   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1546   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1547   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1548 
  1549   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1550   star_n_minus <-- {hypreal,hcomplex}_minus
  1551   star_n_diff <-- {hypreal,hcomplex}_diff
  1552   star_n_mult <-- {hypreal,hcomplex}_mult
  1553   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1554   star_n_le <-- {hypreal,hypnat}_le
  1555   star_n_less <-- {hypreal,hypnat}_less
  1556   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1557   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1558   star_n_abs <-- hypreal_hrabs
  1559   star_n_divide <-- hcomplex_divide
  1560 
  1561   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1562   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1563   star_of_diff <-- hypreal_of_real_diff
  1564   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1565   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1566   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1567   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1568   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1569   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1570   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1571   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1572   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1573   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1574   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1575   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1576   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1577   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1578   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1579   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1580   star_of_power <-- hypreal_of_real_power
  1581   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1582 
  1583 * Hyperreal: new method "transfer" that implements the transfer
  1584 principle of nonstandard analysis. With a subgoal that mentions
  1585 nonstandard types like "'a star", the command "apply transfer"
  1586 replaces it with an equivalent one that mentions only standard types.
  1587 To be successful, all free variables must have standard types; non-
  1588 standard variables must have explicit universal quantifiers.
  1589 
  1590 * Hyperreal: A theory of Taylor series.
  1591 
  1592 
  1593 *** HOLCF ***
  1594 
  1595 * Discontinued special version of 'constdefs' (which used to support
  1596 continuous functions) in favor of the general Pure one with full
  1597 type-inference.
  1598 
  1599 * New simplification procedure for solving continuity conditions; it
  1600 is much faster on terms with many nested lambda abstractions (cubic
  1601 instead of exponential time).
  1602 
  1603 * New syntax for domain package: selector names are now optional.
  1604 Parentheses should be omitted unless argument is lazy, for example:
  1605 
  1606   domain 'a stream = cons "'a" (lazy "'a stream")
  1607 
  1608 * New command 'fixrec' for defining recursive functions with pattern
  1609 matching; defining multiple functions with mutual recursion is also
  1610 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1611 sinr, or any data constructor defined by the domain package. The given
  1612 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1613 syntax and examples.
  1614 
  1615 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1616 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1617 but the proof obligation additionally includes an admissibility
  1618 requirement. The packages generate instances of class cpo or pcpo,
  1619 with continuity and strictness theorems for Rep and Abs.
  1620 
  1621 * HOLCF: Many theorems have been renamed according to a more standard naming
  1622 scheme (INCOMPATIBILITY):
  1623 
  1624   foo_inject:  "foo$x = foo$y ==> x = y"
  1625   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1626   foo_less:    "(foo$x << foo$y) = (x << y)"
  1627   foo_strict:  "foo$UU = UU"
  1628   foo_defined: "... ==> foo$x ~= UU"
  1629   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1630 
  1631 
  1632 *** ZF ***
  1633 
  1634 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1635 including the First Isomorphism Theorem (on quotienting by the kernel
  1636 of a homomorphism).
  1637 
  1638 * ZF/Simplifier: install second copy of type solver that actually
  1639 makes use of TC rules declared to Isar proof contexts (or locales);
  1640 the old version is still required for ML proof scripts.
  1641 
  1642 
  1643 *** Cube ***
  1644 
  1645 * Converted to Isar theory format; use locales instead of axiomatic
  1646 theories.
  1647 
  1648 
  1649 *** ML ***
  1650 
  1651 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1652 for ||>, ||>>, |>>,
  1653 
  1654 * Pure/library.ML no longer defines its own option datatype, but uses
  1655 that of the SML basis, which has constructors NONE and SOME instead of
  1656 None and Some, as well as exception Option.Option instead of OPTION.
  1657 The functions the, if_none, is_some, is_none have been adapted
  1658 accordingly, while Option.map replaces apsome.
  1659 
  1660 * Pure/library.ML: the exception LIST has been given up in favour of
  1661 the standard exceptions Empty and Subscript, as well as
  1662 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1663 superceded by the standard hd and tl functions etc.
  1664 
  1665 A number of basic list functions are no longer exported to the ML
  1666 toplevel, as they are variants of predefined functions.  The following
  1667 suggests how one can translate existing code:
  1668 
  1669     rev_append xs ys = List.revAppend (xs, ys)
  1670     nth_elem (i, xs) = List.nth (xs, i)
  1671     last_elem xs = List.last xs
  1672     flat xss = List.concat xss
  1673     seq fs = List.app fs
  1674     partition P xs = List.partition P xs
  1675     mapfilter f xs = List.mapPartial f xs
  1676 
  1677 * Pure/library.ML: several combinators for linear functional
  1678 transformations, notably reverse application and composition:
  1679 
  1680   x |> f                f #> g
  1681   (x, y) |-> f          f #-> g
  1682 
  1683 * Pure/library.ML: introduced/changed precedence of infix operators:
  1684 
  1685   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1686   infix 2 ?;
  1687   infix 3 o oo ooo oooo;
  1688   infix 4 ~~ upto downto;
  1689 
  1690 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1691 infix operators.
  1692 
  1693 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1694 fold_map support linear functional transformations and nesting.  For
  1695 example:
  1696 
  1697   fold f [x1, ..., xN] y =
  1698     y |> f x1 |> ... |> f xN
  1699 
  1700   (fold o fold) f [xs1, ..., xsN] y =
  1701     y |> fold f xs1 |> ... |> fold f xsN
  1702 
  1703   fold f [x1, ..., xN] =
  1704     f x1 #> ... #> f xN
  1705 
  1706   (fold o fold) f [xs1, ..., xsN] =
  1707     fold f xs1 #> ... #> fold f xsN
  1708 
  1709 * Pure/library.ML: the following selectors on type 'a option are
  1710 available:
  1711 
  1712   the:               'a option -> 'a  (*partial*)
  1713   these:             'a option -> 'a  where 'a = 'b list
  1714   the_default: 'a -> 'a option -> 'a
  1715   the_list:          'a option -> 'a list
  1716 
  1717 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1718 basic operations for association lists, following natural argument
  1719 order; moreover the explicit equality predicate passed here avoids
  1720 potentially expensive polymorphic runtime equality checks.
  1721 The old functions may be expressed as follows:
  1722 
  1723   assoc = uncurry (AList.lookup (op =))
  1724   assocs = these oo AList.lookup (op =)
  1725   overwrite = uncurry (AList.update (op =)) o swap
  1726 
  1727 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1728 
  1729   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1730   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1731 
  1732 replacing make_keylist and keyfilter (occassionally used)
  1733 Naive rewrites:
  1734 
  1735   make_keylist = AList.make
  1736   keyfilter = AList.find (op =)
  1737 
  1738 * eq_fst and eq_snd now take explicit equality parameter, thus
  1739   avoiding eqtypes. Naive rewrites:
  1740 
  1741     eq_fst = eq_fst (op =)
  1742     eq_snd = eq_snd (op =)
  1743 
  1744 * Removed deprecated apl and apr (rarely used).
  1745   Naive rewrites:
  1746 
  1747     apl (n, op) =>>= curry op n
  1748     apr (op, m) =>>= fn n => op (n, m)
  1749 
  1750 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1751 provides a reasonably efficient light-weight implementation of sets as
  1752 lists.
  1753 
  1754 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1755 few new operations; existing lookup and update are now curried to
  1756 follow natural argument order (for use with fold etc.);
  1757 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1758 
  1759 * Pure/General: output via the Isabelle channels of
  1760 writeln/warning/error etc. is now passed through Output.output, with a
  1761 hook for arbitrary transformations depending on the print_mode
  1762 (cf. Output.add_mode -- the first active mode that provides a output
  1763 function wins).  Already formatted output may be embedded into further
  1764 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1765 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1766 accommodate easy composition of diagnostic messages etc.  Programmers
  1767 rarely need to care about Output.output or Output.raw at all, with
  1768 some notable exceptions: Output.output is required when bypassing the
  1769 standard channels (writeln etc.), or in token translations to produce
  1770 properly formatted results; Output.raw is required when capturing
  1771 already output material that will eventually be presented to the user
  1772 a second time.  For the default print mode, both Output.output and
  1773 Output.raw have no effect.
  1774 
  1775 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1776 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1777 cumulative results are displayed at the end of a batch session.
  1778 
  1779 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1780 replaced by File.platform_path and File.shell_path (with appropriate
  1781 hooks).  This provides a clean interface for unusual systems where the
  1782 internal and external process view of file names are different.
  1783 
  1784 * Pure: more efficient orders for basic syntactic entities: added
  1785 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1786 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1787 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1788 orders now -- potential INCOMPATIBILITY for code that depends on a
  1789 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1790 Library.sort_strings on result).
  1791 
  1792 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1793 fold_types traverse types/terms from left to right, observing natural
  1794 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1795 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1796 
  1797 * Pure: name spaces have been refined, with significant changes of the
  1798 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1799 to extern(_table).  The plain name entry path is superceded by a
  1800 general 'naming' context, which also includes the 'policy' to produce
  1801 a fully qualified name and external accesses of a fully qualified
  1802 name; NameSpace.extend is superceded by context dependent
  1803 Sign.declare_name.  Several theory and proof context operations modify
  1804 the naming context.  Especially note Theory.restore_naming and
  1805 ProofContext.restore_naming to get back to a sane state; note that
  1806 Theory.add_path is no longer sufficient to recover from
  1807 Theory.absolute_path in particular.
  1808 
  1809 * Pure: new flags short_names (default false) and unique_names
  1810 (default true) for controlling output of qualified names.  If
  1811 short_names is set, names are printed unqualified.  If unique_names is
  1812 reset, the name prefix is reduced to the minimum required to achieve
  1813 the original result when interning again, even if there is an overlap
  1814 with earlier declarations.
  1815 
  1816 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1817 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1818 (useful for printing error messages).  INCOMPATIBILITY.
  1819 
  1820 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1821 Theory.theory are now identified, referring to the universal
  1822 Context.theory (see Pure/context.ML).  Actual signature and theory
  1823 content is managed as theory data.  The old code and interfaces were
  1824 spread over many files and structures; the new arrangement introduces
  1825 considerable INCOMPATIBILITY to gain more clarity:
  1826 
  1827   Context -- theory management operations (name, identity, inclusion,
  1828     parents, ancestors, merge, etc.), plus generic theory data;
  1829 
  1830   Sign -- logical signature and syntax operations (declaring consts,
  1831     types, etc.), plus certify/read for common entities;
  1832 
  1833   Theory -- logical theory operations (stating axioms, definitions,
  1834     oracles), plus a copy of logical signature operations (consts,
  1835     types, etc.); also a few basic management operations (Theory.copy,
  1836     Theory.merge, etc.)
  1837 
  1838 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1839 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1840 for convenience -- they merely return the theory.
  1841 
  1842 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1843 
  1844 * Pure: the Isar proof context type is already defined early in Pure
  1845 as Context.proof (note that ProofContext.context and Proof.context are
  1846 aliases, where the latter is the preferred name).  This enables other
  1847 Isabelle components to refer to that type even before Isar is present.
  1848 
  1849 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1850 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1851 any of these kinds.  For example, Sign.intern typeK is now
  1852 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1853 Theory.hide_types.  Also note that former
  1854 Theory.hide_classes/types/consts are now
  1855 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1856 internalize their arguments!  INCOMPATIBILITY.
  1857 
  1858 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1859 datatype thmref (with constructors Name and NameSelection) instead of
  1860 plain string -- INCOMPATIBILITY;
  1861 
  1862 * Pure: cases produced by proof methods specify options, where NONE
  1863 means to remove case bindings -- INCOMPATIBILITY in
  1864 (RAW_)METHOD_CASES.
  1865 
  1866 * Pure: the following operations retrieve axioms or theorems from a
  1867 theory node or theory hierarchy, respectively:
  1868 
  1869   Theory.axioms_of: theory -> (string * term) list
  1870   Theory.all_axioms_of: theory -> (string * term) list
  1871   PureThy.thms_of: theory -> (string * thm) list
  1872   PureThy.all_thms_of: theory -> (string * thm) list
  1873 
  1874 * Pure: print_tac now outputs the goal through the trace channel.
  1875 
  1876 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1877 Reference Toplevel.debug (default false) controls detailed printing
  1878 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1879 controls execution profiling -- set to 1 for time and 2 for space
  1880 (both increase the runtime).
  1881 
  1882 * Isar session: The initial use of ROOT.ML is now always timed,
  1883 i.e. the log will show the actual process times, in contrast to the
  1884 elapsed wall-clock time that the outer shell wrapper produces.
  1885 
  1886 * Simplifier: improved handling of bound variables (nameless
  1887 representation, avoid allocating new strings).  Simprocs that invoke
  1888 the Simplifier recursively should use Simplifier.inherit_bounds to
  1889 avoid local name clashes.  Failure to do so produces warnings
  1890 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1891 for further details.
  1892 
  1893 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1894 bindings for all theorems stored within a given theory; this may help
  1895 in porting non-Isar theories to Isar ones, while keeping ML proof
  1896 scripts for the time being.
  1897 
  1898 * ML operator HTML.with_charset specifies the charset begin used for
  1899 generated HTML files.  For example:
  1900 
  1901   HTML.with_charset "utf-8" use_thy "Hebrew";
  1902   HTML.with_charset "utf-8" use_thy "Chinese";
  1903 
  1904 
  1905 *** System ***
  1906 
  1907 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1908 isabelle, isatool etc.).
  1909 
  1910 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1911 isatool doc, isatool mkdir, display_drafts etc.).
  1912 
  1913 * isatool usedir: option -f allows specification of the ML file to be
  1914 used by Isabelle; default is ROOT.ML.
  1915 
  1916 * New isatool version outputs the version identifier of the Isabelle
  1917 distribution being used.
  1918 
  1919 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1920 (containing Boolean satisfiability problems) into Isabelle/HOL
  1921 theories.
  1922 
  1923 
  1924 
  1925 New in Isabelle2004 (April 2004)
  1926 --------------------------------
  1927 
  1928 *** General ***
  1929 
  1930 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1931   Replaces linorder.ML.
  1932 
  1933 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1934   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1935   (\<a>...\<z>), are now considered normal letters, and can therefore
  1936   be used anywhere where an ASCII letter (a...zA...Z) has until
  1937   now. COMPATIBILITY: This obviously changes the parsing of some
  1938   terms, especially where a symbol has been used as a binder, say
  1939   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1940   as an identifier.  Fix it by inserting a space around former
  1941   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1942   existing theory and ML files.
  1943 
  1944 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1945 
  1946 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1947   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1948   a normal (but invisible) letter. For multiple letter subscripts repeat
  1949   \<^isub> like this: x\<^isub>1\<^isub>2.
  1950 
  1951 * Pure: There are now sub-/superscripts that can span more than one
  1952   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1953   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1954   superscript. The new control characters are not identifier parts.
  1955 
  1956 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1957   content of "..." to the latex file instead of \isacntrl... . The "..."
  1958   may consist of any printable characters excluding the end bracket >.
  1959 
  1960 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1961   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1962   declare constants "final", which prevents their being given a definition
  1963   later.  It is useful for constants whose behaviour is fixed axiomatically
  1964   rather than definitionally, such as the meta-logic connectives.
  1965 
  1966 * Pure: 'instance' now handles general arities with general sorts
  1967   (i.e. intersections of classes),
  1968 
  1969 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1970   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1971   It can be changed to alter the colors/layout of generated pages.
  1972 
  1973 
  1974 *** Isar ***
  1975 
  1976 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1977   cut_tac, subgoal_tac and thin_tac:
  1978   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1979     locales are no longer forced to write Isar proof scripts.
  1980     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1981     emulations.
  1982   - INCOMPATIBILITY: names of variables to be instantiated may no
  1983     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1984     This is consistent with the instantiation attribute "where".
  1985 
  1986 * Attributes "where" and "of":
  1987   - Now take type variables of instantiated theorem into account when reading
  1988     the instantiation string.  This fixes a bug that caused instantiated
  1989     theorems to have too special types in some circumstances.
  1990   - "where" permits explicit instantiations of type variables.
  1991 
  1992 * Calculation commands "moreover" and "also" no longer interfere with
  1993   current facts ("this"), admitting arbitrary combinations with "then"
  1994   and derived forms.
  1995 
  1996 * Locales:
  1997   - Goal statements involving the context element "includes" no longer
  1998     generate theorems with internal delta predicates (those ending on
  1999     "_axioms") in the premise.
  2000     Resolve particular premise with <locale>.intro to obtain old form.
  2001   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2002     specification and "includes" elements in goal statement.
  2003   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2004     [intro?] and [elim?] (respectively) by default.
  2005   - Experimental command for instantiation of locales in proof contexts:
  2006         instantiate <label>[<attrs>]: <loc>
  2007     Instantiates locale <loc> and adds all its theorems to the current context
  2008     taking into account their attributes.  Label and attrs are optional
  2009     modifiers, like in theorem declarations.  If present, names of
  2010     instantiated theorems are qualified with <label>, and the attributes
  2011     <attrs> are applied after any attributes these theorems might have already.
  2012       If the locale has assumptions, a chained fact of the form
  2013     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2014     are derived.  The command does not support old-style locales declared
  2015     with "locale (open)".
  2016       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2017 
  2018 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2019   (Isar) contexts.
  2020 
  2021 
  2022 *** HOL ***
  2023 
  2024 * Proof import: new image HOL4 contains the imported library from
  2025   the HOL4 system with about 2500 theorems. It is imported by
  2026   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2027   can be used like any other Isabelle image.  See
  2028   HOL/Import/HOL/README for more information.
  2029 
  2030 * Simplifier:
  2031   - Much improved handling of linear and partial orders.
  2032     Reasoners for linear and partial orders are set up for type classes
  2033     "linorder" and "order" respectively, and are added to the default simpset
  2034     as solvers.  This means that the simplifier can build transitivity chains
  2035     to solve goals from the assumptions.
  2036   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2037     of blast or auto after simplification become unnecessary because the goal
  2038     is solved by simplification already.
  2039 
  2040 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2041     all proved in axiomatic type classes for semirings, rings and fields.
  2042 
  2043 * Numerics:
  2044   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2045     now formalized using the Ring_and_Field theory mentioned above.
  2046   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2047     than before, because now they are set up once in a generic manner.
  2048   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2049     Look for the general versions in Ring_and_Field (and Power if they concern
  2050     exponentiation).
  2051 
  2052 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2053 
  2054 * Records:
  2055   - Record types are now by default printed with their type abbreviation
  2056     instead of the list of all field types. This can be configured via
  2057     the reference "print_record_type_abbr".
  2058   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2059     (not enabled by default).
  2060   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2061     EX x. x = sel r to True (not enabled by default).
  2062   - Tactic "record_split_simp_tac" to split and simplify records added.
  2063 
  2064 * 'specification' command added, allowing for definition by
  2065   specification.  There is also an 'ax_specification' command that
  2066   introduces the new constants axiomatically.
  2067 
  2068 * arith(_tac) is now able to generate counterexamples for reals as well.
  2069 
  2070 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2071 
  2072 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2073   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2074 
  2075 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2076   matrix theory to linear programming.
  2077 
  2078 * Unions and Intersections:
  2079   The latex output syntax of UN and INT has been changed
  2080   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2081   i.e. the index formulae has become a subscript.
  2082   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2083 
  2084 * Unions and Intersections over Intervals:
  2085   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2086   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2087   like in normal math, and corresponding versions for < and for intersection.
  2088 
  2089 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2090   lexicographic dictonary ordering has been added as "lexord".
  2091 
  2092 * ML: the legacy theory structures Int and List have been removed. They had
  2093   conflicted with ML Basis Library structures having the same names.
  2094 
  2095 * 'refute' command added to search for (finite) countermodels.  Only works
  2096   for a fragment of HOL.  The installation of an external SAT solver is
  2097   highly recommended.  See "HOL/Refute.thy" for details.
  2098 
  2099 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2100   formulae under an assignment of free variables to random values.
  2101   In contrast to 'refute', it can deal with inductive datatypes,
  2102   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2103   for examples.
  2104 
  2105 
  2106 *** HOLCF ***
  2107 
  2108 * Streams now come with concatenation and are part of the HOLCF image
  2109 
  2110 
  2111 
  2112 New in Isabelle2003 (May 2003)
  2113 ------------------------------
  2114 
  2115 *** General ***
  2116 
  2117 * Provers/simplifier:
  2118 
  2119   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2120     Assumptions are now subject to complete mutual simplification,
  2121     not just from left to right. The simplifier now preserves
  2122     the order of assumptions.
  2123 
  2124     Potential INCOMPATIBILITY:
  2125 
  2126     -- simp sometimes diverges where the old version did
  2127        not, e.g. invoking simp on the goal
  2128 
  2129         [| P (f x); y = x; f x = f y |] ==> Q
  2130 
  2131        now gives rise to the infinite reduction sequence
  2132 
  2133         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2134 
  2135        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2136        kind of problem.
  2137 
  2138     -- Tactics combining classical reasoner and simplification (such as auto)
  2139        are also affected by this change, because many of them rely on
  2140        simp. They may sometimes diverge as well or yield a different numbers
  2141        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2142        in case of problems. Sometimes subsequent calls to the classical
  2143        reasoner will fail because a preceeding call to the simplifier too
  2144        eagerly simplified the goal, e.g. deleted redundant premises.
  2145 
  2146   - The simplifier trace now shows the names of the applied rewrite rules
  2147 
  2148   - You can limit the number of recursive invocations of the simplifier
  2149     during conditional rewriting (where the simplifie tries to solve the
  2150     conditions before applying the rewrite rule):
  2151     ML "simp_depth_limit := n"
  2152     where n is an integer. Thus you can force termination where previously
  2153     the simplifier would diverge.
  2154 
  2155   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2156 
  2157   - No longer aborts on failed congruence proof.  Instead, the
  2158     congruence is ignored.
  2159 
  2160 * Pure: New generic framework for extracting programs from constructive
  2161   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2162   as HOL/Extraction for some case studies.
  2163 
  2164 * Pure: The main goal of the proof state is no longer shown by default, only
  2165 the subgoals. This behaviour is controlled by a new flag.
  2166    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2167 (ML: Proof.show_main_goal).
  2168 
  2169 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2170 rules whose conclusion matches subgoal 1:
  2171       PG menu: Isabelle/Isar -> Show me -> matching rules
  2172 The rules are ordered by how closely they match the subgoal.
  2173 In particular, rules that solve a subgoal outright are displayed first
  2174 (or rather last, the way they are printed).
  2175 (ML: ProofGeneral.print_intros())
  2176 
  2177 * Pure: New flag trace_unify_fail causes unification to print
  2178 diagnostic information (PG: in trace buffer) when it fails. This is
  2179 useful for figuring out why single step proofs like rule, erule or
  2180 assumption failed.
  2181 
  2182 * Pure: Locale specifications now produce predicate definitions
  2183 according to the body of text (covering assumptions modulo local
  2184 definitions); predicate "loc_axioms" covers newly introduced text,
  2185 while "loc" is cumulative wrt. all included locale expressions; the
  2186 latter view is presented only on export into the global theory
  2187 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2188 on the old view without predicates;
  2189 
  2190 * Pure: predefined locales "var" and "struct" are useful for sharing
  2191 parameters (as in CASL, for example); just specify something like
  2192 ``var x + var y + struct M'' as import;
  2193 
  2194 * Pure: improved thms_containing: proper indexing of facts instead of
  2195 raw theorems; check validity of results wrt. current name space;
  2196 include local facts of proof configuration (also covers active
  2197 locales), cover fixed variables in index; may use "_" in term
  2198 specification; an optional limit for the number of printed facts may
  2199 be given (the default is 40);
  2200 
  2201 * Pure: disallow duplicate fact bindings within new-style theory files
  2202 (batch-mode only);
  2203 
  2204 * Provers: improved induct method: assumptions introduced by case
  2205 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2206 the goal statement); "foo" still refers to all facts collectively;
  2207 
  2208 * Provers: the function blast.overloaded has been removed: all constants
  2209 are regarded as potentially overloaded, which improves robustness in exchange
  2210 for slight decrease in efficiency;
  2211 
  2212 * Provers/linorder: New generic prover for transitivity reasoning over
  2213 linear orders.  Note: this prover is not efficient!
  2214 
  2215 * Isar: preview of problems to finish 'show' now produce an error
  2216 rather than just a warning (in interactive mode);
  2217 
  2218 
  2219 *** HOL ***
  2220 
  2221 * arith(_tac)
  2222 
  2223  - Produces a counter example if it cannot prove a goal.
  2224    Note that the counter example may be spurious if the goal is not a formula
  2225    of quantifier-free linear arithmetic.
  2226    In ProofGeneral the counter example appears in the trace buffer.
  2227 
  2228  - Knows about div k and mod k where k is a numeral of type nat or int.
  2229 
  2230  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2231    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2232    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2233 
  2234 * simp's arithmetic capabilities have been enhanced a bit: it now
  2235 takes ~= in premises into account (by performing a case split);
  2236 
  2237 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2238 are distributed over a sum of terms;
  2239 
  2240 * New tactic "trans_tac" and method "trans" instantiate
  2241 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2242 "<=", "<" and "=").
  2243 
  2244 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2245 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2246 
  2247 * 'typedef' command has new option "open" to suppress the set
  2248 definition;
  2249 
  2250 * functions Min and Max on finite sets have been introduced (theory
  2251 Finite_Set);
  2252 
  2253 * attribute [symmetric] now works for relations as well; it turns
  2254 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2255 
  2256 * induct over a !!-quantified statement (say !!x1..xn):
  2257   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2258 
  2259 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2260 %x. None. Warning: empty_def now refers to the previously hidden definition
  2261 of the empty set.
  2262 
  2263 * Algebra: formalization of classical algebra.  Intended as base for
  2264 any algebraic development in Isabelle.  Currently covers group theory
  2265 (up to Sylow's theorem) and ring theory (Universal Property of
  2266 Univariate Polynomials).  Contributions welcome;
  2267 
  2268 * GroupTheory: deleted, since its material has been moved to Algebra;
  2269 
  2270 * Complex: new directory of the complex numbers with numeric constants,
  2271 nonstandard complex numbers, and some complex analysis, standard and
  2272 nonstandard (Jacques Fleuriot);
  2273 
  2274 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2275 
  2276 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2277 Fleuriot);
  2278 
  2279 * Real/HahnBanach: updated and adapted to locales;
  2280 
  2281 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2282 Gray and Kramer);
  2283 
  2284 * UNITY: added the Meier-Sanders theory of progress sets;
  2285 
  2286 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2287 as abstract algorithms, instantiated to the JVM;
  2288 
  2289 * Bali: Java source language formalization. Type system, operational
  2290 semantics, axiomatic semantics. Supported language features:
  2291 classes, interfaces, objects,virtual methods, static methods,
  2292 static/instance fields, arrays, access modifiers, definite
  2293 assignment, exceptions.
  2294 
  2295 
  2296 *** ZF ***
  2297 
  2298 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2299 universe, etc.);
  2300 
  2301 * Main ZF: virtually all theories converted to new-style format;
  2302 
  2303 
  2304 *** ML ***
  2305 
  2306 * Pure: Tactic.prove provides sane interface for internal proofs;
  2307 omits the infamous "standard" operation, so this is more appropriate
  2308 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2309 
  2310 * Pure: improved error reporting of simprocs;
  2311 
  2312 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2313 up simprocs;
  2314 
  2315 
  2316 *** Document preparation ***
  2317 
  2318 * uses \par instead of \\ for line breaks in theory text. This may
  2319 shift some page breaks in large documents. To get the old behaviour
  2320 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2321 
  2322 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2323 other packages
  2324 
  2325 * \<euro> now needs package babel/greek instead of marvosym (which
  2326 broke \Rightarrow)
  2327 
  2328 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2329 textcomp package)
  2330 
  2331 
  2332 
  2333 New in Isabelle2002 (March 2002)
  2334 --------------------------------
  2335 
  2336 *** Document preparation ***
  2337 
  2338 * greatly simplified document preparation setup, including more
  2339 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2340 instructive isatool mkdir; users should basically be able to get
  2341 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2342 users may run a separate document processing stage manually like this:
  2343 "isatool usedir -D output HOL Test && isatool document Test/output";
  2344 
  2345 * theory dependency graph may now be incorporated into documents;
  2346 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2347 with \includegraphics of LaTeX;
  2348 
  2349 * proper spacing of consecutive markup elements, especially text
  2350 blocks after section headings;
  2351 
  2352 * support bold style (for single symbols only), input syntax is like
  2353 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2354 
  2355 * \<bullet> is now output as bold \cdot by default, which looks much
  2356 better in printed text;
  2357 
  2358 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2359 note that these symbols are currently unavailable in Proof General /
  2360 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2361 
  2362 * isatool latex no longer depends on changed TEXINPUTS, instead
  2363 isatool document copies the Isabelle style files to the target
  2364 location;
  2365 
  2366 
  2367 *** Isar ***
  2368 
  2369 * Pure/Provers: improved proof by cases and induction;
  2370   - 'case' command admits impromptu naming of parameters (such as
  2371     "case (Suc n)");
  2372   - 'induct' method divinates rule instantiation from the inductive
  2373     claim; no longer requires excessive ?P bindings for proper
  2374     instantiation of cases;
  2375   - 'induct' method properly enumerates all possibilities of set/type
  2376     rules; as a consequence facts may be also passed through *type*
  2377     rules without further ado;
  2378   - 'induct' method now derives symbolic cases from the *rulified*
  2379     rule (before it used to rulify cases stemming from the internal
  2380     atomized version); this means that the context of a non-atomic
  2381     statement becomes is included in the hypothesis, avoiding the
  2382     slightly cumbersome show "PROP ?case" form;
  2383   - 'induct' may now use elim-style induction rules without chaining
  2384     facts, using ``missing'' premises from the goal state; this allows
  2385     rules stemming from inductive sets to be applied in unstructured
  2386     scripts, while still benefitting from proper handling of non-atomic
  2387     statements; NB: major inductive premises need to be put first, all
  2388     the rest of the goal is passed through the induction;
  2389   - 'induct' proper support for mutual induction involving non-atomic
  2390     rule statements (uses the new concept of simultaneous goals, see
  2391     below);
  2392   - append all possible rule selections, but only use the first
  2393     success (no backtracking);
  2394   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2395   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2396   - added 'print_induct_rules' (covered by help item in recent Proof
  2397     General versions);
  2398   - moved induct/cases attributes to Pure, methods to Provers;
  2399   - generic method setup instantiated for FOL and HOL;
  2400 
  2401 * Pure: support multiple simultaneous goal statements, for example
  2402 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2403 meta-level mechanism, this acts as if several individual goals had
  2404 been stated separately; in particular common proof methods need to be
  2405 repeated in order to cover all claims; note that a single elimination
  2406 step is *not* sufficient to establish the two conjunctions, so this
  2407 fails:
  2408 
  2409   assume "A & B" then have A and B ..   (*".." fails*)
  2410 
  2411 better use "obtain" in situations as above; alternative refer to
  2412 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2413 
  2414 * Pure: proper integration with ``locales''; unlike the original
  2415 version by Florian Kammller, Isar locales package high-level proof
  2416 contexts rather than raw logical ones (e.g. we admit to include
  2417 attributes everywhere); operations on locales include merge and
  2418 rename; support for implicit arguments (``structures''); simultaneous
  2419 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2420 some examples;
  2421 
  2422 * Pure: the following commands have been ``localized'', supporting a
  2423 target locale specification "(in name)": 'lemma', 'theorem',
  2424 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2425 stored both within the locale and at the theory level (exported and
  2426 qualified by the locale name);
  2427 
  2428 * Pure: theory goals may now be specified in ``long'' form, with
  2429 ad-hoc contexts consisting of arbitrary locale elements. for example
  2430 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2431 definitions may be given, too); the result is a meta-level rule with
  2432 the context elements being discharged in the obvious way;
  2433 
  2434 * Pure: new proof command 'using' allows to augment currently used
  2435 facts after a goal statement ('using' is syntactically analogous to
  2436 'apply', but acts on the goal's facts only); this allows chained facts
  2437 to be separated into parts given before and after a claim, as in
  2438 ``from a and b have C using d and e <proof>'';
  2439 
  2440 * Pure: renamed "antecedent" case to "rule_context";
  2441 
  2442 * Pure: new 'judgment' command records explicit information about the
  2443 object-logic embedding (used by several tools internally); no longer
  2444 use hard-wired "Trueprop";
  2445 
  2446 * Pure: added 'corollary' command;
  2447 
  2448 * Pure: fixed 'token_translation' command;
  2449 
  2450 * Pure: removed obsolete 'exported' attribute;
  2451 
  2452 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2453 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2454 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2455 
  2456 * Pure: method 'atomize' presents local goal premises as object-level
  2457 statements (atomic meta-level propositions); setup controlled via
  2458 rewrite rules declarations of 'atomize' attribute; example
  2459 application: 'induct' method with proper rule statements in improper
  2460 proof *scripts*;
  2461 
  2462 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2463 now consider the syntactic context of assumptions, giving a better
  2464 chance to get type-inference of the arguments right (this is
  2465 especially important for locales);
  2466 
  2467 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2468 mode;
  2469 
  2470 * Pure/obtain: the formal conclusion "thesis", being marked as
  2471 ``internal'', may no longer be reference directly in the text;
  2472 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2473 situations;
  2474 
  2475 * Pure: generic 'sym' attribute which declares a rule both as pure
  2476 'elim?' and for the 'symmetric' operation;
  2477 
  2478 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2479 text; the fixed correlation with particular command syntax has been
  2480 discontinued;
  2481 
  2482 * Pure: new method 'rules' is particularly well-suited for proof
  2483 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2484 but often produces more compact proof terms with less detours;
  2485 
  2486 * Pure/Provers/classical: simplified integration with pure rule
  2487 attributes and methods; the classical "intro?/elim?/dest?"
  2488 declarations coincide with the pure ones; the "rule" method no longer
  2489 includes classically swapped intros; "intro" and "elim" methods no
  2490 longer pick rules from the context; also got rid of ML declarations
  2491 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2492 INCOMPATIBILITY;
  2493 
  2494 * Provers/classical: attribute 'swapped' produces classical inversions
  2495 of introduction rules;
  2496 
  2497 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2498 rules instead of full simplifier context; 'iff' attribute handles
  2499 conditional rules;
  2500 
  2501 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2502 
  2503 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2504 "(permissive)" option to recover old behavior;
  2505 
  2506 * HOL: 'inductive' no longer features separate (collective) attributes
  2507 for 'intros' (was found too confusing);
  2508 
  2509 * HOL: properly declared induction rules less_induct and
  2510 wf_induct_rule;
  2511 
  2512 
  2513 *** HOL ***
  2514 
  2515 * HOL: moved over to sane numeral syntax; the new policy is as
  2516 follows:
  2517 
  2518   - 0 and 1 are polymorphic constants, which are defined on any
  2519   numeric type (nat, int, real etc.);
  2520 
  2521   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2522   binary representation internally;
  2523 
  2524   - type nat has special constructor Suc, and generally prefers Suc 0
  2525   over 1::nat and Suc (Suc 0) over 2::nat;
  2526 
  2527 This change may cause significant problems of INCOMPATIBILITY; here
  2528 are some hints on converting existing sources:
  2529 
  2530   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2531   entities, so expressions involving "-" (unary or binary minus) need
  2532   to be spaced properly;
  2533 
  2534   - existing occurrences of "1" may need to be constraint "1::nat" or
  2535   even replaced by Suc 0; similar for old "2";
  2536 
  2537   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2538 
  2539   - remove all special provisions on numerals in proofs;
  2540 
  2541 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2542 representation (depends on bin_arith_simps in the default context);
  2543 
  2544 * HOL: symbolic syntax for x^2 (numeral 2);
  2545 
  2546 * HOL: the class of all HOL types is now called "type" rather than
  2547 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2548 in axclass/classes, instance/arities, and (usually rare) occurrences
  2549 in typings (of consts etc.); internally the class is called
  2550 "HOL.type", ML programs should refer to HOLogic.typeS;
  2551 
  2552 * HOL/record package improvements:
  2553   - new derived operations "fields" to build a partial record section,
  2554     "extend" to promote a fixed record to a record scheme, and
  2555     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2556     declared as simp by default;
  2557   - shared operations ("more", "fields", etc.) now need to be always
  2558     qualified) --- potential INCOMPATIBILITY;
  2559   - removed "make_scheme" operations (use "make" with "extend") --
  2560     INCOMPATIBILITY;
  2561   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2562   - provides cases/induct rules for use with corresponding Isar
  2563     methods (for concrete records, record schemes, concrete more
  2564     parts, and schematic more parts -- in that order);
  2565   - internal definitions directly based on a light-weight abstract
  2566     theory of product types over typedef rather than datatype;
  2567 
  2568 * HOL: generic code generator for generating executable ML code from
  2569 specifications; specific support for HOL constructs such as inductive
  2570 datatypes and sets, as well as recursive functions; can be invoked
  2571 via 'generate_code' theory section;
  2572 
  2573 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2574 
  2575 * HOL: consolidated and renamed several theories.  In particular:
  2576         Ord.thy has been absorbed into HOL.thy
  2577         String.thy has been absorbed into List.thy
  2578 
  2579 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2580 (beware of argument permutation!);
  2581 
  2582 * HOL: linorder_less_split superseded by linorder_cases;
  2583 
  2584 * HOL/List: "nodups" renamed to "distinct";
  2585 
  2586 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2587 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2588   - Ex_def has changed, now need to use some_eq_ex
  2589 
  2590 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2591 in this (rare) case use:
  2592 
  2593   delSWrapper "split_all_tac"
  2594   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2595 
  2596 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2597 MAY FAIL;
  2598 
  2599 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2600 Isabelle's type classes, ^ on functions and relations has too general
  2601 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2602 necessary to attach explicit type constraints;
  2603 
  2604 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2605 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2606 renamed accordingly (eg "compI" -> "rel_compI").
  2607 
  2608 * HOL: syntax translations now work properly with numerals and records
  2609 expressions;
  2610 
  2611 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2612 of "lam" -- INCOMPATIBILITY;
  2613 
  2614 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2615 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2616 renamed "Product_Type.unit";
  2617 
  2618 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2619 
  2620 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2621 the "cases" method);
  2622 
  2623 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2624 Florian Kammller);
  2625 
  2626 * HOL/IMP: updated and converted to new-style theory format; several
  2627 parts turned into readable document, with proper Isar proof texts and
  2628 some explanations (by Gerwin Klein);
  2629 
  2630 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2631 
  2632 * HOL-Hyperreal is now a logic image;
  2633 
  2634 
  2635 *** HOLCF ***
  2636 
  2637 * Isar: consts/constdefs supports mixfix syntax for continuous
  2638 operations;
  2639 
  2640 * Isar: domain package adapted to new-style theory format, e.g. see
  2641 HOLCF/ex/Dnat.thy;
  2642 
  2643 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2644 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2645 lift.induct_tac, always use UU instead of Undef;
  2646 
  2647 * HOLCF/IMP: updated and converted to new-style theory;
  2648 
  2649 
  2650 *** ZF ***
  2651 
  2652 * Isar: proper integration of logic-specific tools and packages,
  2653 including theory commands '(co)inductive', '(co)datatype',
  2654 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2655 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2656 
  2657 * theory Main no longer includes AC; for the Axiom of Choice, base
  2658 your theory on Main_ZFC;
  2659 
  2660 * the integer library now covers quotients and remainders, with many
  2661 laws relating division to addition, multiplication, etc.;
  2662 
  2663 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2664 typeless version of the formalism;
  2665 
  2666 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2667 format;
  2668 
  2669 * ZF/Induct: new directory for examples of inductive definitions,
  2670 including theory Multiset for multiset orderings; converted to
  2671 new-style theory format;
  2672 
  2673 * ZF: many new theorems about lists, ordinals, etc.;
  2674 
  2675 
  2676 *** General ***
  2677 
  2678 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2679 variable proof controls level of detail: 0 = no proofs (only oracle
  2680 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2681 also ref manual for further ML interfaces;
  2682 
  2683 * Pure/axclass: removed obsolete ML interface
  2684 goal_subclass/goal_arity;
  2685 
  2686 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2687 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2688 separate tokens, so expressions involving minus need to be spaced
  2689 properly;
  2690 
  2691 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2692 rather than "infixl" or "infixr";
  2693 
  2694 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2695 sort constraint specifications in type inference; e.g. "x::_::foo"
  2696 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2697 type variable);
  2698 
  2699 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2700 control output of nested => (types); the default behavior is
  2701 "type_brackets";
  2702 
  2703 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2704 tokens into AST constants;
  2705 
  2706 * Pure/syntax: prefer later declarations of translations and print
  2707 translation functions; potential INCOMPATIBILITY: need to reverse
  2708 multiple declarations for same syntax element constant;
  2709 
  2710 * Pure/show_hyps reset by default (in accordance to existing Isar
  2711 practice);
  2712 
  2713 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2714 addSafter;
  2715 
  2716 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2717 as well;
  2718 
  2719 * system: tested support for MacOS X; should be able to get Isabelle +
  2720 Proof General to work in a plain Terminal after installing Poly/ML
  2721 (e.g. from the Isabelle distribution area) and GNU bash alone
  2722 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2723 support requires further installations, e.g. from
  2724 http://fink.sourceforge.net/);
  2725 
  2726 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2727 
  2728 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2729 of 40 MB), cf. ML_OPTIONS;
  2730 
  2731 * system: Proof General keywords specification is now part of the
  2732 Isabelle distribution (see etc/isar-keywords.el);
  2733 
  2734 * system: support for persistent Proof General sessions (refrain from
  2735 outdating all loaded theories on startup); user may create writable
  2736 logic images like this: ``isabelle -q HOL Test'';
  2737 
  2738 * system: smart selection of Isabelle process versus Isabelle
  2739 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2740 run both "isabelle" and "Isabelle" even if file names are badly
  2741 damaged (executable inspects the case of the first letter of its own
  2742 name); added separate "isabelle-process" and "isabelle-interface";
  2743 
  2744 * system: refrain from any attempt at filtering input streams; no
  2745 longer support ``8bit'' encoding of old isabelle font, instead proper
  2746 iso-latin characters may now be used; the related isatools
  2747 "symbolinput" and "nonascii" have disappeared as well;
  2748 
  2749 * system: removed old "xterm" interface (the print modes "xterm" and
  2750 "xterm_color" are still available for direct use in a suitable
  2751 terminal);
  2752 
  2753 
  2754 
  2755 New in Isabelle99-2 (February 2001)
  2756 -----------------------------------
  2757 
  2758 *** Overview of INCOMPATIBILITIES ***
  2759 
  2760 * HOL: please note that theories in the Library and elsewhere often use the
  2761 new-style (Isar) format; to refer to their theorems in an ML script you must
  2762 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2763 
  2764 * HOL: inductive package no longer splits induction rule aggressively,
  2765 but only as far as specified by the introductions given; the old
  2766 format may be recovered via ML function complete_split_rule or attribute
  2767 'split_rule (complete)';
  2768 
  2769 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2770 gfp_Tarski to gfp_unfold;
  2771 
  2772 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2773 
  2774 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2775 relation); infix "^^" has been renamed "``"; infix "``" has been
  2776 renamed "`"; "univalent" has been renamed "single_valued";
  2777 
  2778 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2779 operation;
  2780 
  2781 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2782 
  2783 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2784 
  2785 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2786 consequence, it is no longer monotonic wrt. the local goal context
  2787 (which is now passed through the inductive cases);
  2788 
  2789 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2790 \<gg> to \<ggreater>;
  2791 
  2792 
  2793 *** Document preparation ***
  2794 
  2795 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2796 available: are "it" for near math-mode best-style output, "sl" for
  2797 slanted text style, and "tt" for plain type-writer; if no
  2798 \isabellestyle command is given, output is according to slanted
  2799 type-writer);
  2800 
  2801 * support sub/super scripts (for single symbols only), input syntax is
  2802 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2803 
  2804 * some more standard symbols; see Appendix A of the system manual for
  2805 the complete list of symbols defined in isabellesym.sty;
  2806 
  2807 * improved isabelle style files; more abstract symbol implementation
  2808 (should now use \isamath{...} and \isatext{...} in custom symbol
  2809 definitions);
  2810 
  2811 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2812 state; Note that presentation of goal states does not conform to
  2813 actual human-readable proof documents.  Please do not include goal
  2814 states into document output unless you really know what you are doing!
  2815 
  2816 * proper indentation of antiquoted output with proportional LaTeX
  2817 fonts;
  2818 
  2819 * no_document ML operator temporarily disables LaTeX document
  2820 generation;
  2821 
  2822 * isatool unsymbolize tunes sources for plain ASCII communication;
  2823 
  2824 
  2825 *** Isar ***
  2826 
  2827 * Pure: Isar now suffers initial goal statements to contain unbound
  2828 schematic variables (this does not conform to actual readable proof
  2829 documents, due to unpredictable outcome and non-compositional proof
  2830 checking); users who know what they are doing may use schematic goals
  2831 for Prolog-style synthesis of proven results;
  2832 
  2833 * Pure: assumption method (an implicit finishing) now handles actual
  2834 rules as well;
  2835 
  2836 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2837 initial goal, declare "that" only as Pure intro (only for single
  2838 steps); the "that" rule assumption may now be involved in implicit
  2839 finishing, thus ".." becomes a feasible for trivial obtains;
  2840 
  2841 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2842 instance proofs may be performed by "..";
  2843 
  2844 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2845 statements as well;
  2846 
  2847 * Pure: more robust selection of calculational rules;
  2848 
  2849 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2850 rule (as well as the assumption rule);
  2851 
  2852 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2853 lemmas, using the graph browser tool;
  2854 
  2855 * Pure: predict failure of "show" in interactive mode;
  2856 
  2857 * Pure: 'thms_containing' now takes actual terms as arguments;
  2858 
  2859 * HOL: improved method 'induct' --- now handles non-atomic goals
  2860 (potential INCOMPATIBILITY); tuned error handling;
  2861 
  2862 * HOL: cases and induct rules now provide explicit hints about the
  2863 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2864 any remaining facts are inserted into the goal verbatim;
  2865 
  2866 * HOL: local contexts (aka cases) may now contain term bindings as
  2867 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2868 the result to be shown in each case;
  2869 
  2870 * HOL: added 'recdef_tc' command;
  2871 
  2872 * isatool convert assists in eliminating legacy ML scripts;
  2873 
  2874 
  2875 *** HOL ***
  2876 
  2877 * HOL/Library: a collection of generic theories to be used together
  2878 with main HOL; the theory loader path already includes this directory
  2879 by default; the following existing theories have been moved here:
  2880 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2881 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2882 
  2883 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2884 modelling and verification task performed in Isabelle/HOL +
  2885 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2886 
  2887 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2888 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2889 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2890 'domain', this makes the theory consistent with mathematical
  2891 literature;
  2892 
  2893 * HOL basics: added overloaded operations "inverse" and "divide"
  2894 (infix "/"), syntax for generic "abs" operation, generic summation
  2895 operator \<Sum>;
  2896 
  2897 * HOL/typedef: simplified package, provide more useful rules (see also
  2898 HOL/subset.thy);
  2899 
  2900 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2901 now expressed as a proper nested rule (old-style tactic scripts may
  2902 require atomize_strip_tac to cope with non-atomic premises);
  2903 
  2904 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2905 to "split_conv" (old name still available for compatibility);
  2906 
  2907 * HOL: improved concrete syntax for strings (e.g. allows translation
  2908 rules with string literals);
  2909 
  2910 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2911  and Fleuriot's mechanization of analysis, including the transcendental
  2912  functions for the reals;
  2913 
  2914 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2915 
  2916 
  2917 *** CTT ***
  2918 
  2919 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2920 "lam" is displayed as TWO lambda-symbols
  2921 
  2922 * CTT: theory Main now available, containing everything (that is, Bool
  2923 and Arith);
  2924 
  2925 
  2926 *** General ***
  2927 
  2928 * Pure: the Simplifier has been implemented properly as a derived rule
  2929 outside of the actual kernel (at last!); the overall performance
  2930 penalty in practical applications is about 50%, while reliability of
  2931 the Isabelle inference kernel has been greatly improved;
  2932 
  2933 * print modes "brackets" and "no_brackets" control output of nested =>
  2934 (types) and ==> (props); the default behaviour is "brackets";
  2935 
  2936 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2937 as assumptions as well;
  2938 
  2939 * system: support Poly/ML 4.0;
  2940 
  2941 * system: isatool install handles KDE version 1 or 2;
  2942 
  2943 
  2944 
  2945 New in Isabelle99-1 (October 2000)
  2946 ----------------------------------
  2947 
  2948 *** Overview of INCOMPATIBILITIES ***
  2949 
  2950 * HOL: simplification of natural numbers is much changed; to partly
  2951 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2952 issue the following ML commands:
  2953 
  2954   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2955   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2956 
  2957 * HOL: simplification no longer dives into case-expressions; this is
  2958 controlled by "t.weak_case_cong" for each datatype t;
  2959 
  2960 * HOL: nat_less_induct renamed to less_induct;
  2961 
  2962 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2963 fixsome to patch .thy and .ML sources automatically;
  2964 
  2965   select_equality  -> some_equality
  2966   select_eq_Ex     -> some_eq_ex
  2967   selectI2EX       -> someI2_ex
  2968   selectI2         -> someI2
  2969   selectI          -> someI
  2970   select1_equality -> some1_equality
  2971   Eps_sym_eq       -> some_sym_eq_trivial
  2972   Eps_eq           -> some_eq_trivial
  2973 
  2974 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2975 
  2976 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2977 instead);
  2978 
  2979 * HOL: the recursion equations generated by 'recdef' are now called
  2980 f.simps instead of f.rules;
  2981 
  2982 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2983 
  2984 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2985 sometimes be needed;
  2986 
  2987 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2988 
  2989 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2990 
  2991 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2992 product is now "<*>" instead of "Times"; the lexicographic product is
  2993 now "<*lex*>" instead of "**";
  2994 
  2995 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2996 of main HOL, but was unused); better use HOL's datatype package;
  2997 
  2998 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2999 the old syntax may be recovered as follows:
  3000 
  3001   syntax (symbols)
  3002     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3003       (infixl "\\<oplus>" 100)
  3004 
  3005 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3006 
  3007 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3008 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3009 internally;
  3010 
  3011 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3012 changed from A/r to A//r;
  3013 
  3014 * ZF: new treatment of arithmetic (nat & int) may break some old
  3015 proofs;
  3016 
  3017 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3018 rulify -> rule_format, elimify -> elim_format, ...);
  3019 
  3020 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3021 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3022 should have to change intro!! to intro? only); replaced "delrule" by
  3023 "rule del";
  3024 
  3025 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3026 
  3027 * Provers: strengthened force_tac by using new first_best_tac;
  3028 
  3029 * LaTeX document preparation: several changes of isabelle.sty (see
  3030 lib/texinputs);
  3031 
  3032 
  3033 *** Document preparation ***
  3034 
  3035 * formal comments (text blocks etc.) in new-style theories may now
  3036 contain antiquotations of thm/prop/term/typ/text to be presented
  3037 according to latex print mode; concrete syntax is like this:
  3038 @{term[show_types] "f(x) = a + x"};
  3039 
  3040 * isatool mkdir provides easy setup of Isabelle session directories,
  3041 including proper document sources;
  3042 
  3043 * generated LaTeX sources are now deleted after successful run
  3044 (isatool document -c); may retain a copy somewhere else via -D option
  3045 of isatool usedir;
  3046 
  3047 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3048 style files, achieving self-contained LaTeX sources and simplifying
  3049 LaTeX debugging;
  3050 
  3051 * old-style theories now produce (crude) LaTeX output as well;
  3052 
  3053 * browser info session directories are now self-contained (may be put
  3054 on WWW server seperately); improved graphs of nested sessions; removed
  3055 graph for 'all sessions';
  3056 
  3057 * several improvements in isabelle style files; \isabellestyle{it}
  3058 produces fake math mode output; \isamarkupheader is now \section by
  3059 default; see lib/texinputs/isabelle.sty etc.;
  3060 
  3061 
  3062 *** Isar ***
  3063 
  3064 * Isar/Pure: local results and corresponding term bindings are now
  3065 subject to Hindley-Milner polymorphism (similar to ML); this
  3066 accommodates incremental type-inference very nicely;
  3067 
  3068 * Isar/Pure: new derived language element 'obtain' supports
  3069 generalized existence reasoning;
  3070 
  3071 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3072 support accumulation of results, without applying any rules yet;
  3073 useful to collect intermediate results without explicit name
  3074 references, and for use with transitivity rules with more than 2
  3075 premises;
  3076 
  3077 * Isar/Pure: scalable support for case-analysis type proofs: new
  3078 'case' language element refers to local contexts symbolically, as
  3079 produced by certain proof methods; internally, case names are attached
  3080 to theorems as "tags";
  3081 
  3082 * Isar/Pure: theory command 'hide' removes declarations from
  3083 class/type/const name spaces;
  3084 
  3085 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3086 indicate potential overloading;
  3087 
  3088 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3089 
  3090 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3091 "{a,b,c}" instead of {a,b,c};
  3092 
  3093 * Isar/Pure now provides its own version of intro/elim/dest
  3094 attributes; useful for building new logics, but beware of confusion
  3095 with the version in Provers/classical;
  3096 
  3097 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3098 case name 'antecedent';
  3099 
  3100 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3101 to the current context is now done automatically);
  3102 
  3103 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3104 for definining proof methods in ML;
  3105 
  3106 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3107 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3108 most cases, one should have to change intro!! to intro? only);
  3109 replaced "delrule" by "rule del";
  3110 
  3111 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3112 'symmetric' attribute (the latter supercedes [RS sym]);
  3113 
  3114 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3115 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3116 well (including splits);
  3117 
  3118 * Isar/Provers: Simplifier and Classical methods now support all kind
  3119 of modifiers used in the past, including 'cong', 'iff', etc.
  3120 
  3121 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3122 of Simplifier and Classical reasoner);
  3123 
  3124 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3125 now support named cases; major packages (inductive, datatype, primrec,
  3126 recdef) support case names and properly name parameters;
  3127 
  3128 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3129 monotonicity conditions are extracted to be proven at end of
  3130 calculations;
  3131 
  3132 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3133 method anyway;
  3134 
  3135 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3136 split_if split_if_asm; datatype package provides theorems foo.splits =
  3137 foo.split foo.split_asm for each datatype;
  3138 
  3139 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3140 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3141 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3142 use "(cases (simplified))" method in proper proof texts);
  3143 
  3144 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3145 
  3146 * Isar: names of theorems etc. may be natural numbers as well;
  3147 
  3148 * Isar: 'pr' command: optional arguments for goals_limit and
  3149 ProofContext.prems_limit; no longer prints theory contexts, but only
  3150 proof states;
  3151 
  3152 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3153 additional print modes to be specified; e.g. "pr(latex)" will print
  3154 proof state according to the Isabelle LaTeX style;
  3155 
  3156 * Isar: improved support for emulating tactic scripts, including proof
  3157 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3158 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3159 (for HOL datatypes);
  3160 
  3161 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3162 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3163 'proof method scripts' have to be in depth-first order;
  3164 
  3165 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3166 
  3167 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3168 should instead use individual commands for printing items
  3169 (print_commands, print_methods etc.);
  3170 
  3171 * Isar: added 'nothing' --- the empty list of theorems;
  3172 
  3173 
  3174 *** HOL ***
  3175 
  3176 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3177 corresponding virtual machine and a specification of its bytecode
  3178 verifier and a lightweight bytecode verifier, including proofs of
  3179 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3180 Cornelia Pusch (see also the homepage of project Bali at
  3181 http://isabelle.in.tum.de/Bali/);
  3182 
  3183 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3184 Clemens Ballarin;
  3185 
  3186 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3187 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3188 Rasmussen;
  3189 
  3190 * HOL/Lattice: fundamental concepts of lattice theory and order
  3191 structures, including duals, properties of bounds versus algebraic
  3192 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3193 Theorem for complete lattices etc.; may also serve as a demonstration
  3194 for abstract algebraic reasoning using axiomatic type classes, and
  3195 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3196 
  3197 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3198 von Oheimb;
  3199 
  3200 * HOL/IMPP: extension of IMP with local variables and mutually
  3201 recursive procedures, by David von Oheimb;
  3202 
  3203 * HOL/Lambda: converted into new-style theory and document;
  3204 
  3205 * HOL/ex/Multiquote: example of multiple nested quotations and
  3206 anti-quotations -- basically a generalized version of de-Bruijn
  3207 representation; very useful in avoiding lifting of operations;
  3208 
  3209 * HOL/record: added general record equality rule to simpset; fixed
  3210 select-update simplification procedure to handle extended records as
  3211 well; admit "r" as field name;
  3212 
  3213 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3214 other numeric types and also as the identity of groups, rings, etc.;
  3215 
  3216 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3217 Types nat and int belong to this axclass;
  3218 
  3219 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3220    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3221    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3222   two terms #m*u and #n*u are replaced by #(m+n)*u
  3223     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3224   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3225     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3226 
  3227 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3228 powerful prover for predicate logic but knows nothing of clasets; see
  3229 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3230 
  3231 * HOL: new version of "case_tac" subsumes both boolean case split and
  3232 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3233 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3234 
  3235 * HOL: simplification no longer dives into case-expressions: only the
  3236 selector expression is simplified, but not the remaining arms; to
  3237 enable full simplification of case-expressions for datatype t, you may
  3238 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3239 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3240 
  3241 * HOL/recdef: the recursion equations generated by 'recdef' for
  3242 function 'f' are now called f.simps instead of f.rules; if all
  3243 termination conditions are proved automatically, these simplification
  3244 rules are added to the simpset, as in primrec; rules may be named
  3245 individually as well, resulting in a separate list of theorems for
  3246 each equation;
  3247 
  3248 * HOL/While is a new theory that provides a while-combinator. It
  3249 permits the definition of tail-recursive functions without the
  3250 provision of a termination measure. The latter is necessary once the
  3251 invariant proof rule for while is applied.
  3252 
  3253 * HOL: new (overloaded) notation for the set of elements below/above
  3254 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3255 
  3256 * HOL: theorems impI, allI, ballI bound as "strip";
  3257 
  3258 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3259 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3260 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3261 
  3262 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3263 
  3264 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3265 main HOL, but was unused);
  3266 
  3267 * HOL: fewer consts declared as global (e.g. have to refer to
  3268 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3269 
  3270 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3271 in case of overlap with user translations (e.g. judgements over
  3272 tuples); (note that the underlying logical represenation is still
  3273 bogus);
  3274 
  3275 
  3276 *** ZF ***
  3277 
  3278 * ZF: simplification automatically cancels common terms in arithmetic
  3279 expressions over nat and int;
  3280 
  3281 * ZF: new treatment of nat to minimize type-checking: all operators
  3282 coerce their operands to a natural number using the function natify,
  3283 making the algebraic laws unconditional;
  3284 
  3285 * ZF: as above, for int: operators coerce their operands to an integer
  3286 using the function intify;
  3287 
  3288 * ZF: the integer library now contains many of the usual laws for the
  3289 orderings, including $<=, and monotonicity laws for $+ and $*;
  3290 
  3291 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3292 simplification;
  3293 
  3294 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3295 to the simplifier and classical reasoner simultaneously;
  3296 
  3297 
  3298 *** General ***
  3299 
  3300 * Provers: blast_tac now handles actual object-logic rules as
  3301 assumptions; note that auto_tac uses blast_tac internally as well;
  3302 
  3303 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3304 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3305 
  3306 * Provers: delrules now handles destruct rules as well (no longer need
  3307 explicit make_elim);
  3308 
  3309 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3310   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3311 use instead the strong form,
  3312   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3313 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3314 from destruct-rules;
  3315 
  3316 * Provers: Simplifier.easy_setup provides a fast path to basic
  3317 Simplifier setup for new object-logics;
  3318 
  3319 * Pure: AST translation rules no longer require constant head on LHS;
  3320 
  3321 * Pure: improved name spaces: ambiguous output is qualified; support
  3322 for hiding of names;
  3323 
  3324 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3325 XSYMBOL_HOME; no longer need to do manual configuration in most
  3326 situations;
  3327 
  3328 * system: compression of ML heaps images may now be controlled via -c
  3329 option of isabelle and isatool usedir (currently only observed by
  3330 Poly/ML);
  3331 
  3332 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3333 useful for remote X11);
  3334 
  3335 * system: provide TAGS file for Isabelle sources;
  3336 
  3337 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3338 order;
  3339 
  3340 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3341 timing flag supersedes proof_timing and Toplevel.trace;
  3342 
  3343 * ML: new combinators |>> and |>>> for incremental transformations
  3344 with secondary results (e.g. certain theory extensions):
  3345 
  3346 * ML: PureThy.add_defs gets additional argument to indicate potential
  3347 overloading (usually false);
  3348 
  3349 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3350 results;
  3351 
  3352 
  3353 
  3354 New in Isabelle99 (October 1999)
  3355 --------------------------------
  3356 
  3357 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3358 
  3359 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3360 are no longer simplified.  (This allows the simplifier to unfold recursive
  3361 functional programs.)  To restore the old behaviour, declare
  3362 
  3363     Delcongs [if_weak_cong];
  3364 
  3365 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3366 complement;
  3367 
  3368 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3369 
  3370 * HOL/datatype: mutual_induct_tac no longer exists --
  3371   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3372 
  3373 * HOL/typedef: fixed type inference for representing set; type
  3374 arguments now have to occur explicitly on the rhs as type constraints;
  3375 
  3376 * ZF: The con_defs part of an inductive definition may no longer refer
  3377 to constants declared in the same theory;
  3378 
  3379 * HOL, ZF: the function mk_cases, generated by the inductive
  3380 definition package, has lost an argument.  To simplify its result, it
  3381 uses the default simpset instead of a supplied list of theorems.
  3382 
  3383 * HOL/List: the constructors of type list are now Nil and Cons;
  3384 
  3385 * Simplifier: the type of the infix ML functions
  3386         setSSolver addSSolver setSolver addSolver
  3387 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3388 for packaging solvers. A solver is created via
  3389         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3390 where the string argument is only a comment.
  3391 
  3392 
  3393 *** Proof tools ***
  3394 
  3395 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3396 decision procedure for linear arithmetic. Currently it is used for
  3397 types `nat', `int', and `real' in HOL (see below); it can, should and
  3398 will be instantiated for other types and logics as well.
  3399 
  3400 * The simplifier now accepts rewrite rules with flexible heads, eg
  3401      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3402   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3403   matching.
  3404 
  3405 
  3406 *** General ***
  3407 
  3408 * New Isabelle/Isar subsystem provides an alternative to traditional
  3409 tactical theorem proving; together with the ProofGeneral/isar user
  3410 interface it offers an interactive environment for developing human
  3411 readable proof documents (Isar == Intelligible semi-automated
  3412 reasoning); for further information see isatool doc isar-ref,
  3413 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3414 
  3415 * improved and simplified presentation of theories: better HTML markup
  3416 (including colors), graph views in several sizes; isatool usedir now
  3417 provides a proper interface for user theories (via -P option); actual
  3418 document preparation based on (PDF)LaTeX is available as well (for
  3419 new-style theories only); see isatool doc system for more information;
  3420 
  3421 * native support for Proof General, both for classic Isabelle and
  3422 Isabelle/Isar;
  3423 
  3424 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3425 using the graph browser tool;
  3426 
  3427 * Isabelle manuals now also available as PDF;
  3428 
  3429 * theory loader rewritten from scratch (may not be fully
  3430 bug-compatible); old loadpath variable has been replaced by show_path,
  3431 add_path, del_path, reset_path functions; new operations such as
  3432 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3433 isatool doc ref);
  3434 
  3435 * improved isatool install: option -k creates KDE application icon,
  3436 option -p DIR installs standalone binaries;
  3437 
  3438 * added ML_PLATFORM setting (useful for cross-platform installations);
  3439 more robust handling of platform specific ML images for SML/NJ;
  3440 
  3441 * the settings environment is now statically scoped, i.e. it is never
  3442 created again in sub-processes invoked from isabelle, isatool, or
  3443 Isabelle;
  3444 
  3445 * path element specification '~~' refers to '$ISABELLE_HOME';
  3446 
  3447 * in locales, the "assumes" and "defines" parts may be omitted if
  3448 empty;
  3449 
  3450 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3451 long arrows);
  3452 
  3453 * new print_mode "HTML";
  3454 
  3455 * new flag show_tags controls display of tags of theorems (which are
  3456 basically just comments that may be attached by some tools);
  3457 
  3458 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3459 mode and goal output format:
  3460 
  3461 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3462 244c244
  3463 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3464 ---
  3465 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3466 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3467 181c181
  3468 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3469 ---
  3470 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3471 
  3472 * function bind_thms stores lists of theorems (cf. bind_thm);
  3473 
  3474 * new shorthand tactics ftac, eatac, datac, fatac;
  3475 
  3476 * qed (and friends) now accept "" as result name; in that case the
  3477 theorem is not stored, but proper checks and presentation of the
  3478 result still apply;
  3479 
  3480 * theorem database now also indexes constants "Trueprop", "all",
  3481 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3482 
  3483 
  3484 *** HOL ***
  3485 
  3486 ** HOL arithmetic **
  3487 
  3488 * There are now decision procedures for linear arithmetic over nat and
  3489 int:
  3490 
  3491 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3492 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3493 are treated as atomic; subformulae not involving type `nat' or `int'
  3494 are ignored; quantified subformulae are ignored unless they are
  3495 positive universal or negative existential. The tactic has to be
  3496 invoked by hand and can be a little bit slow. In particular, the
  3497 running time is exponential in the number of occurrences of `min' and
  3498 `max', and `-' on `nat'.
  3499 
  3500 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3501 (negated) (in)equalities among the premises and the conclusion into
  3502 account (i.e. no compound formulae) and does not know about `min' and
  3503 `max', and `-' on `nat'. It is fast and is used automatically by the
  3504 simplifier.
  3505 
  3506 NB: At the moment, these decision procedures do not cope with mixed
  3507 nat/int formulae where the two parts interact, such as `m < n ==>
  3508 int(m) < int(n)'.
  3509 
  3510 * HOL/Numeral provides a generic theory of numerals (encoded
  3511 efficiently as bit strings); setup for types nat/int/real is in place;
  3512 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3513 int, existing theories and proof scripts may require a few additional
  3514 type constraints;
  3515 
  3516 * integer division and remainder can now be performed on constant
  3517 arguments;
  3518 
  3519 * many properties of integer multiplication, division and remainder
  3520 are now available;
  3521 
  3522 * An interface to the Stanford Validity Checker (SVC) is available through the
  3523 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3524 are proved automatically.  SVC must be installed separately, and its results
  3525 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3526 invocation of the underlying oracle).  For SVC see
  3527   http://verify.stanford.edu/SVC
  3528 
  3529 * IsaMakefile: the HOL-Real target now builds an actual image;
  3530 
  3531 
  3532 ** HOL misc **
  3533 
  3534 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3535 (in Isabelle/Isar) -- by Gertrud Bauer;
  3536 
  3537 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3538 analysis for assembly languages with subtypes;
  3539 
  3540 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3541 -- avoids syntactic ambiguities and treats state, transition, and
  3542 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3543 changed syntax and (many) tactics;
  3544 
  3545 * HOL/inductive: Now also handles more general introduction rules such
  3546   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3547   theorems are now maintained within the theory (maintained via the
  3548   "mono" attribute);
  3549 
  3550 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3551   (using function types) such as
  3552 
  3553   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3554 
  3555 * HOL/record: record_simproc (part of the default simpset) takes care
  3556 of selectors applied to updated records; record_split_tac is no longer
  3557 part of the default claset; update_defs may now be removed from the
  3558 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3559 
  3560   claset_ref () := claset() addSWrapper record_split_wrapper;
  3561   Delsimprocs [record_simproc]
  3562 
  3563 * HOL/typedef: fixed type inference for representing set; type
  3564 arguments now have to occur explicitly on the rhs as type constraints;
  3565 
  3566 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3567 names rather than an ML expression;
  3568 
  3569 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3570 supplied later.  Program schemes can be defined, such as
  3571     "While B C s = (if B s then While B C (C s) else s)"
  3572 where the well-founded relation can be chosen after B and C have been given.
  3573 
  3574 * HOL/List: the constructors of type list are now Nil and Cons;
  3575 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3576 course, ML tools referring to List.list.op # etc. have to be adapted;
  3577 
  3578 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3579 disabled by default; run isabelle with option -m HOL to get back to
  3580 the original Gordon/HOL-style output;
  3581 
  3582 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3583 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3584 
  3585 * HOL basic syntax simplified (more orthogonal): all variants of
  3586 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3587 Eps operator is provided as well: "SOME x. P[x]";
  3588 
  3589 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3590 
  3591 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3592 thus available for user theories;
  3593 
  3594 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3595 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3596 time;
  3597 
  3598 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3599 several times and then mp;
  3600 
  3601 
  3602 *** LK ***
  3603 
  3604 * the notation <<...>> is now available as a notation for sequences of
  3605 formulas;
  3606 
  3607 * the simplifier is now installed
  3608 
  3609 * the axiom system has been generalized (thanks to Soren Heilmann)
  3610 
  3611 * the classical reasoner now has a default rule database
  3612 
  3613 
  3614 *** ZF ***
  3615 
  3616 * new primrec section allows primitive recursive functions to be given
  3617 directly (as in HOL) over datatypes and the natural numbers;
  3618 
  3619 * new tactics induct_tac and exhaust_tac for induction (or case
  3620 analysis) over datatypes and the natural numbers;
  3621 
  3622 * the datatype declaration of type T now defines the recursor T_rec;
  3623 
  3624 * simplification automatically does freeness reasoning for datatype
  3625 constructors;
  3626 
  3627 * automatic type-inference, with AddTCs command to insert new
  3628 type-checking rules;
  3629 
  3630 * datatype introduction rules are now added as Safe Introduction rules
  3631 to the claset;
  3632 
  3633 * the syntax "if P then x else y" is now available in addition to
  3634 if(P,x,y);
  3635 
  3636 
  3637 *** Internal programming interfaces ***
  3638 
  3639 * tuned simplifier trace output; new flag debug_simp;
  3640 
  3641 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3642 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3643 
  3644 * AxClass.axclass_tac lost the theory argument;
  3645 
  3646 * tuned current_goals_markers semantics: begin / end goal avoids
  3647 printing empty lines;
  3648 
  3649 * removed prs and prs_fn hook, which was broken because it did not
  3650 include \n in its semantics, forcing writeln to add one
  3651 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3652 string -> unit if you really want to output text without newline;
  3653 
  3654 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3655 plain output, interface builders may have to enable 'isabelle_font'
  3656 mode to get Isabelle font glyphs as before;
  3657 
  3658 * refined token_translation interface; INCOMPATIBILITY: output length
  3659 now of type real instead of int;
  3660 
  3661 * theory loader actions may be traced via new ThyInfo.add_hook
  3662 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3663 your own database of information attached to *whole* theories -- as
  3664 opposed to intra-theory data slots offered via TheoryDataFun;
  3665 
  3666 * proper handling of dangling sort hypotheses (at last!);
  3667 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3668 extra sort hypotheses that can be witnessed from the type signature;
  3669 the force_strip_shyps flag is gone, any remaining shyps are simply
  3670 left in the theorem (with a warning issued by strip_shyps_warning);
  3671 
  3672 
  3673 
  3674 New in Isabelle98-1 (October 1998)
  3675 ----------------------------------
  3676 
  3677 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3678 
  3679 * several changes of automated proof tools;
  3680 
  3681 * HOL: major changes to the inductive and datatype packages, including
  3682 some minor incompatibilities of theory syntax;
  3683 
  3684 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3685 called `inj_on';
  3686 
  3687 * HOL: removed duplicate thms in Arith:
  3688   less_imp_add_less  should be replaced by  trans_less_add1
  3689   le_imp_add_le      should be replaced by  trans_le_add1
  3690 
  3691 * HOL: unary minus is now overloaded (new type constraints may be
  3692 required);
  3693 
  3694 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3695 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3696 now taken as an integer constant.
  3697 
  3698 * Pure: ML function 'theory_of' renamed to 'theory';
  3699 
  3700 
  3701 *** Proof tools ***
  3702 
  3703 * Simplifier:
  3704   1. Asm_full_simp_tac is now more aggressive.
  3705      1. It will sometimes reorient premises if that increases their power to
  3706         simplify.
  3707      2. It does no longer proceed strictly from left to right but may also
  3708         rotate premises to achieve further simplification.
  3709      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3710      old Asm_full_simp_tac in that it does not rotate premises.
  3711   2. The simplifier now knows a little bit about nat-arithmetic.
  3712 
  3713 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3714 allows for selected deletion of wrappers, by introduction of names for
  3715 wrapper functionals.  This implies that addbefore, addSbefore,
  3716 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3717 and that adding two tactics with the same name overwrites the first
  3718 one (emitting a warning).
  3719   type wrapper = (int -> tactic) -> (int -> tactic)
  3720   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3721   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3722   delWrapper, delSWrapper: claset *  string            -> claset
  3723   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3724 
  3725 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3726 semantics; addbefore now affects only the unsafe part of step_tac
  3727 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3728 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3729 by Force_tac;
  3730 
  3731 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3732 compWrapper; added safe wrapper (and access functions for it);
  3733 
  3734 * HOL/split_all_tac is now much faster and fails if there is nothing
  3735 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3736 and the names of the automatically generated variables have changed.
  3737 split_all_tac has moved within claset() from unsafe wrappers to safe
  3738 wrappers, which means that !!-bound variables are split much more
  3739 aggressively, and safe_tac and clarify_tac now split such variables.
  3740 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3741 Note: the same holds for record_split_tac, which does the job of
  3742 split_all_tac for record fields.
  3743 
  3744 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3745 permanently to the default simpset using Addsplits just like
  3746 Addsimps. They can be removed via Delsplits just like
  3747 Delsimps. Lower-case versions are also available.
  3748 
  3749 * HOL/Simplifier: The rule split_if is now part of the default
  3750 simpset. This means that the simplifier will eliminate all occurrences
  3751 of if-then-else in the conclusion of a goal. To prevent this, you can
  3752 either remove split_if completely from the default simpset by
  3753 `Delsplits [split_if]' or remove it in a specific call of the
  3754 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3755 other case splitting rules to/from the default simpset: every datatype
  3756 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3757 t is the name of the datatype).
  3758 
  3759 * Classical reasoner / Simplifier combination: new force_tac (and
  3760 derivatives Force_tac, force) combines rewriting and classical
  3761 reasoning (and whatever other tools) similarly to auto_tac, but is
  3762 aimed to solve the given subgoal completely.
  3763 
  3764 
  3765 *** General ***
  3766 
  3767 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3768 and `goalw': the theory is no longer needed as an explicit argument -
  3769 the current theory context is used; assumptions are no longer returned
  3770 at the ML-level unless one of them starts with ==> or !!; it is
  3771 recommended to convert to these new commands using isatool fixgoal
  3772 (backup your sources first!);
  3773 
  3774 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3775 the current theory context, and 'theory' to lookup stored theories;
  3776 
  3777 * new theory section 'locale' for declaring constants, assumptions and
  3778 definitions that have local scope;
  3779 
  3780 * new theory section 'nonterminals' for purely syntactic types;
  3781 
  3782 * new theory section 'setup' for generic ML setup functions
  3783 (e.g. package initialization);
  3784 
  3785 * the distribution now includes Isabelle icons: see
  3786 lib/logo/isabelle-{small,tiny}.xpm;
  3787 
  3788 * isatool install - install binaries with absolute references to
  3789 ISABELLE_HOME/bin;
  3790 
  3791 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3792 
  3793 * print mode 'emacs' reserved for Isamode;
  3794 
  3795 * support multiple print (ast) translations per constant name;
  3796 
  3797 * theorems involving oracles are now printed with a suffixed [!];
  3798 
  3799 
  3800 *** HOL ***
  3801 
  3802 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3803 
  3804 * HOL/inductive package reorganized and improved: now supports mutual
  3805 definitions such as
  3806 
  3807   inductive EVEN ODD
  3808     intrs
  3809       null "0 : EVEN"
  3810       oddI "n : EVEN ==> Suc n : ODD"
  3811       evenI "n : ODD ==> Suc n : EVEN"
  3812 
  3813 new theorem list "elims" contains an elimination rule for each of the
  3814 recursive sets; inductive definitions now handle disjunctive premises
  3815 correctly (also ZF);
  3816 
  3817 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3818 "mutual_induct" no longer exists - the induction rule is always
  3819 contained in "induct";
  3820 
  3821 
  3822 * HOL/datatype package re-implemented and greatly improved: now
  3823 supports mutually recursive datatypes such as
  3824 
  3825   datatype
  3826     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3827             | SUM ('a aexp) ('a aexp)
  3828             | DIFF ('a aexp) ('a aexp)
  3829             | NUM 'a
  3830   and
  3831     'a bexp = LESS ('a aexp) ('a aexp)
  3832             | AND ('a bexp) ('a bexp)
  3833             | OR ('a bexp) ('a bexp)
  3834 
  3835 as well as indirectly recursive datatypes such as
  3836 
  3837   datatype
  3838     ('a, 'b) term = Var 'a
  3839                   | App 'b ((('a, 'b) term) list)
  3840 
  3841 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3842 induction on mutually / indirectly recursive datatypes.
  3843 
  3844 Primrec equations are now stored in theory and can be accessed via
  3845 <function_name>.simps.
  3846 
  3847 INCOMPATIBILITIES:
  3848 
  3849   - Theories using datatypes must now have theory Datatype as an
  3850     ancestor.
  3851   - The specific <typename>.induct_tac no longer exists - use the
  3852     generic induct_tac instead.
  3853   - natE has been renamed to nat.exhaust - use exhaust_tac
  3854     instead of res_inst_tac ... natE. Note that the variable
  3855     names in nat.exhaust differ from the names in natE, this
  3856     may cause some "fragile" proofs to fail.
  3857   - The theorems split_<typename>_case and split_<typename>_case_asm
  3858     have been renamed to <typename>.split and <typename>.split_asm.
  3859   - Since default sorts of type variables are now handled correctly,
  3860     some datatype definitions may have to be annotated with explicit
  3861     sort constraints.
  3862   - Primrec definitions no longer require function name and type
  3863     of recursive argument.
  3864 
  3865 Consider using isatool fixdatatype to adapt your theories and proof
  3866 scripts to the new package (backup your sources first!).
  3867 
  3868 
  3869 * HOL/record package: considerably improved implementation; now
  3870 includes concrete syntax for record types, terms, updates; theorems
  3871 for surjective pairing and splitting !!-bound record variables; proof
  3872 support is as follows:
  3873 
  3874   1) standard conversions (selectors or updates applied to record
  3875 constructor terms) are part of the standard simpset;
  3876 
  3877   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3878 made part of standard simpset and claset via addIffs;
  3879 
  3880   3) a tactic for record field splitting (record_split_tac) is part of
  3881 the standard claset (addSWrapper);
  3882 
  3883 To get a better idea about these rules you may retrieve them via
  3884 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3885 the name of your record type.
  3886 
  3887 The split tactic 3) conceptually simplifies by the following rule:
  3888 
  3889   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3890 
  3891 Thus any record variable that is bound by meta-all will automatically
  3892 blow up into some record constructor term, consequently the
  3893 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3894 solve record problems automatically.
  3895 
  3896 
  3897 * reorganized the main HOL image: HOL/Integ and String loaded by
  3898 default; theory Main includes everything;
  3899 
  3900 * automatic simplification of integer sums and comparisons, using cancellation;
  3901 
  3902 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3903 
  3904 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3905 
  3906 * many new identities for unions, intersections, set difference, etc.;
  3907 
  3908 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3909 called split_if, split_split, split_sum_case and split_nat_case (to go
  3910 with add/delsplits);
  3911 
  3912 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3913 (?x::unit) = (); this is made part of the default simpset, which COULD
  3914 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3915 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3916 unit_abs_eta_conv is added in order to counter the effect of
  3917 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3918 %u.f();
  3919 
  3920 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3921 makes more sense);
  3922 
  3923 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3924   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3925   disjointness reasoning but breaking a few old proofs.
  3926 
  3927 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3928 to 'converse' from 'inverse' (for compatibility with ZF and some
  3929 literature);
  3930 
  3931 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3932 the well-founded relation;
  3933 
  3934 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3935     Compl A.  The "Compl" syntax remains available as input syntax for this
  3936     release ONLY.
  3937 
  3938 * HOL/Update: new theory of function updates:
  3939     f(a:=b) == %x. if x=a then b else f x
  3940 may also be iterated as in f(a:=b,c:=d,...);
  3941 
  3942 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3943 
  3944 * HOL/List:
  3945   - new function list_update written xs[i:=v] that updates the i-th
  3946     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3947   - new function `upt' written [i..j(] which generates the list
  3948     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3949     bound write [i..j], which is a shorthand for [i..j+1(].
  3950   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3951 
  3952 * HOL/Arith:
  3953   - removed 'pred' (predecessor) function;
  3954   - generalized some theorems about n-1;
  3955   - many new laws about "div" and "mod";
  3956   - new laws about greatest common divisors (see theory ex/Primes);
  3957 
  3958 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3959 instead of "inverse";
  3960 
  3961 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3962   of the multiset ordering;
  3963 
  3964 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3965   (not included by default);
  3966 
  3967 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3968 
  3969 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3970   programs, i.e. different program variables may have different types.
  3971 
  3972 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3973   [previously, this check worked only if the rewrite rule was unconditional]
  3974   Now rew can involve either definitions or equalities (either == or =).
  3975 
  3976 
  3977 *** ZF ***
  3978 
  3979 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3980   only the theorems proved on ZF.ML;
  3981 
  3982 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3983   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3984   disjointness reasoning but breaking a few old proofs.
  3985 
  3986 * ZF/Update: new theory of function updates
  3987     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3988   may also be iterated as in f(a:=b,c:=d,...);
  3989 
  3990 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3991 
  3992 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3993   [previously, this check worked only if the rewrite rule was unconditional]
  3994   Now rew can involve either definitions or equalities (either == or =).
  3995 
  3996 * case_tac provided for compatibility with HOL
  3997     (like the old excluded_middle_tac, but with subgoals swapped)
  3998 
  3999 
  4000 *** Internal programming interfaces ***
  4001 
  4002 * Pure: several new basic modules made available for general use, see
  4003 also src/Pure/README;
  4004 
  4005 * improved the theory data mechanism to support encapsulation (data
  4006 kind name replaced by private Object.kind, acting as authorization
  4007 key); new type-safe user interface via functor TheoryDataFun; generic
  4008 print_data function becomes basically useless;
  4009 
  4010 * removed global_names compatibility flag -- all theory declarations
  4011 are qualified by default;
  4012 
  4013 * module Pure/Syntax now offers quote / antiquote translation
  4014 functions (useful for Hoare logic etc. with implicit dependencies);
  4015 see HOL/ex/Antiquote for an example use;
  4016 
  4017 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4018 cterm -> thm;
  4019 
  4020 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4021 subgoal;
  4022 
  4023 * Display.print_goals function moved to Locale.print_goals;
  4024 
  4025 * standard print function for goals supports current_goals_markers
  4026 variable for marking begin of proof, end of proof, start of goal; the
  4027 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4028 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4029 for example;
  4030 
  4031 
  4032 
  4033 New in Isabelle98 (January 1998)
  4034 --------------------------------
  4035 
  4036 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4037 
  4038 * changed lexical syntax of terms / types: dots made part of long
  4039 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4040 
  4041 * simpset (and claset) reference variable replaced by functions
  4042 simpset / simpset_ref;
  4043 
  4044 * no longer supports theory aliases (via merge) and non-trivial
  4045 implicit merge of thms' signatures;
  4046 
  4047 * most internal names of constants changed due to qualified names;
  4048 
  4049 * changed Pure/Sequence interface (see Pure/seq.ML);
  4050 
  4051 
  4052 *** General Changes ***
  4053 
  4054 * hierachically structured name spaces (for consts, types, axms, thms
  4055 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4056 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4057 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4058 long_names for fully qualified output names; NOTE: ML programs
  4059 (special tactics, packages etc.) referring to internal names may have
  4060 to be adapted to cope with fully qualified names; in case of severe
  4061 backward campatibility problems try setting 'global_names' at compile
  4062 time to have enrything declared within a flat name space; one may also
  4063 fine tune name declarations in theories via the 'global' and 'local'
  4064 section;
  4065 
  4066 * reimplemented the implicit simpset and claset using the new anytype
  4067 data filed in signatures; references simpset:simpset ref etc. are
  4068 replaced by functions simpset:unit->simpset and
  4069 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4070 to patch your ML files accordingly;
  4071 
  4072 * HTML output now includes theory graph data for display with Java
  4073 applet or isatool browser; data generated automatically via isatool
  4074 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4075 
  4076 * defs may now be conditional; improved rewrite_goals_tac to handle
  4077 conditional equations;
  4078 
  4079 * defs now admits additional type arguments, using TYPE('a) syntax;
  4080 
  4081 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4082 creates a new theory node; implicit merge of thms' signatures is
  4083 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4084 transfer:theory->thm->thm in (rare) cases;
  4085 
  4086 * improved handling of draft signatures / theories; draft thms (and
  4087 ctyps, cterms) are automatically promoted to real ones;
  4088 
  4089 * slightly changed interfaces for oracles: admit many per theory, named
  4090 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4091 
  4092 * print_goals: optional output of const types (set show_consts and
  4093 show_types);
  4094 
  4095 * improved output of warnings (###) and errors (***);
  4096 
  4097 * subgoal_tac displays a warning if the new subgoal has type variables;
  4098 
  4099 * removed old README and Makefiles;
  4100 
  4101 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4102 
  4103 * removed obsolete init_pps and init_database;
  4104 
  4105 * deleted the obsolete tactical STATE, which was declared by
  4106     fun STATE tacfun st = tacfun st st;
  4107 
  4108 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4109 (which abbreviates $HOME);
  4110 
  4111 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4112 use isatool fixseq to adapt your ML programs (this works for fully
  4113 qualified references to the Sequence structure only!);
  4114 
  4115 * use_thy no longer requires writable current directory; it always
  4116 reloads .ML *and* .thy file, if either one is out of date;
  4117 
  4118 
  4119 *** Classical Reasoner ***
  4120 
  4121 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4122 tactics that use classical reasoning to simplify a subgoal without
  4123 splitting it into several subgoals;
  4124 
  4125 * Safe_tac: like safe_tac but uses the default claset;
  4126 
  4127 
  4128 *** Simplifier ***
  4129 
  4130 * added simplification meta rules:
  4131     (asm_)(full_)simplify: simpset -> thm -> thm;
  4132 
  4133 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4134 logics (again);
  4135 
  4136 * added prems argument to simplification procedures;
  4137 
  4138 * HOL, FOL, ZF: added infix function `addsplits':
  4139   instead of `<simpset> setloop (split_tac <thms>)'
  4140   you can simply write `<simpset> addsplits <thms>'
  4141 
  4142 
  4143 *** Syntax ***
  4144 
  4145 * TYPE('a) syntax for type reflection terms;
  4146 
  4147 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4148 
  4149 * pretty printer: changed order of mixfix annotation preference (again!);
  4150 
  4151 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4152 
  4153 
  4154 *** HOL ***
  4155 
  4156 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4157   with `addloop' of the simplifier to faciliate case splitting in premises.
  4158 
  4159 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4160 
  4161 * HOL/Auth: new protocol proofs including some for the Internet
  4162   protocol TLS;
  4163 
  4164 * HOL/Map: new theory of `maps' a la VDM;
  4165 
  4166 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4167 cancelling out common nat summands from =, <, <= (in)equalities, or
  4168 differences; simplification procedures nat_cancel_factor for
  4169 cancelling common factor from =, <, <= (in)equalities over natural
  4170 sums; nat_cancel contains both kinds of procedures, it is installed by
  4171 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4172 
  4173 * HOL/simplifier: terms of the form
  4174   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4175   are rewritten to
  4176   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4177   and those of the form
  4178   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4179   are rewritten to
  4180   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4181 
  4182 * HOL/datatype
  4183   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4184 
  4185   P(t_case f1 ... fn x) =
  4186      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4187         ...
  4188        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4189      )
  4190 
  4191   and a theorem `split_t_case_asm' of the form
  4192 
  4193   P(t_case f1 ... fn x) =
  4194     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4195         ...
  4196        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4197      )
  4198   which can be added to a simpset via `addsplits'. The existing theorems
  4199   expand_list_case and expand_option_case have been renamed to
  4200   split_list_case and split_option_case.
  4201 
  4202 * HOL/Arithmetic:
  4203   - `pred n' is automatically converted to `n-1'.
  4204     Users are strongly encouraged not to use `pred' any longer,
  4205     because it will disappear altogether at some point.
  4206   - Users are strongly encouraged to write "0 < n" rather than
  4207     "n ~= 0". Theorems and proof tools have been modified towards this
  4208     `standard'.
  4209 
  4210 * HOL/Lists:
  4211   the function "set_of_list" has been renamed "set" (and its theorems too);
  4212   the function "nth" now takes its arguments in the reverse order and
  4213   has acquired the infix notation "!" as in "xs!n".
  4214 
  4215 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4216 
  4217 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4218   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4219 
  4220 * HOL/record: extensible records with schematic structural subtyping
  4221 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4222 still lacks various theorems and concrete record syntax;
  4223 
  4224 
  4225 *** HOLCF ***
  4226 
  4227 * removed "axioms" and "generated by" sections;
  4228 
  4229 * replaced "ops" section by extended "consts" section, which is capable of
  4230   handling the continuous function space "->" directly;
  4231 
  4232 * domain package:
  4233   . proves theorems immediately and stores them in the theory,
  4234   . creates hierachical name space,
  4235   . now uses normal mixfix annotations (instead of cinfix...),
  4236   . minor changes to some names and values (for consistency),
  4237   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4238   . separator between mutual domain defs: changed "," to "and",
  4239   . improved handling of sort constraints;  now they have to
  4240     appear on the left-hand side of the equations only;
  4241 
  4242 * fixed LAM <x,y,zs>.b syntax;
  4243 
  4244 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4245 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4246 
  4247 
  4248 *** FOL and ZF ***
  4249 
  4250 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4251   with `addloop' of the simplifier to faciliate case splitting in premises.
  4252 
  4253 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4254 in HOL, they strip ALL and --> from proved theorems;
  4255 
  4256 
  4257 
  4258 New in Isabelle94-8 (May 1997)
  4259 ------------------------------
  4260 
  4261 *** General Changes ***
  4262 
  4263 * new utilities to build / run / maintain Isabelle etc. (in parts
  4264 still somewhat experimental); old Makefiles etc. still functional;
  4265 
  4266 * new 'Isabelle System Manual';
  4267 
  4268 * INSTALL text, together with ./configure and ./build scripts;
  4269 
  4270 * reimplemented type inference for greater efficiency, better error
  4271 messages and clean internal interface;
  4272 
  4273 * prlim command for dealing with lots of subgoals (an easier way of
  4274 setting goals_limit);
  4275 
  4276 
  4277 *** Syntax ***
  4278 
  4279 * supports alternative (named) syntax tables (parser and pretty
  4280 printer); internal interface is provided by add_modesyntax(_i);
  4281 
  4282 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4283 be used in conjunction with the Isabelle symbol font; uses the
  4284 "symbols" syntax table;
  4285 
  4286 * added token_translation interface (may translate name tokens in
  4287 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4288 the current print_mode); IMPORTANT: user print translation functions
  4289 are responsible for marking newly introduced bounds
  4290 (Syntax.mark_boundT);
  4291 
  4292 * token translations for modes "xterm" and "xterm_color" that display
  4293 names in bold, underline etc. or colors (which requires a color
  4294 version of xterm);
  4295 
  4296 * infixes may now be declared with names independent of their syntax;
  4297 
  4298 * added typed_print_translation (like print_translation, but may
  4299 access type of constant);
  4300 
  4301 
  4302 *** Classical Reasoner ***
  4303 
  4304 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4305 some limitations.  Blast_tac...
  4306   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4307   + ignores elimination rules that don't have the correct format
  4308         (the conclusion MUST be a formula variable)
  4309   + ignores types, which can make HOL proofs fail
  4310   + rules must not require higher-order unification, e.g. apply_type in ZF
  4311     [message "Function Var's argument not a bound variable" relates to this]
  4312   + its proof strategy is more general but can actually be slower
  4313 
  4314 * substitution with equality assumptions no longer permutes other
  4315 assumptions;
  4316 
  4317 * minor changes in semantics of addafter (now called addaltern); renamed
  4318 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4319 (and access functions for it);
  4320 
  4321 * improved combination of classical reasoner and simplifier:
  4322   + functions for handling clasimpsets
  4323   + improvement of addss: now the simplifier is called _after_ the
  4324     safe steps.
  4325   + safe variant of addss called addSss: uses safe simplifications
  4326     _during_ the safe steps. It is more complete as it allows multiple
  4327     instantiations of unknowns (e.g. with slow_tac).
  4328 
  4329 *** Simplifier ***
  4330 
  4331 * added interface for simplification procedures (functions that
  4332 produce *proven* rewrite rules on the fly, depending on current
  4333 redex);
  4334 
  4335 * ordering on terms as parameter (used for ordered rewriting);
  4336 
  4337 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4338 
  4339 * the solver is now split into a safe and an unsafe part.
  4340 This should be invisible for the normal user, except that the
  4341 functions setsolver and addsolver have been renamed to setSolver and
  4342 addSolver; added safe_asm_full_simp_tac;
  4343 
  4344 
  4345 *** HOL ***
  4346 
  4347 * a generic induction tactic `induct_tac' which works for all datatypes and
  4348 also for type `nat';
  4349 
  4350 * a generic case distinction tactic `exhaust_tac' which works for all
  4351 datatypes and also for type `nat';
  4352 
  4353 * each datatype comes with a function `size';
  4354 
  4355 * patterns in case expressions allow tuple patterns as arguments to
  4356 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4357 
  4358 * primrec now also works with type nat;
  4359 
  4360 * recdef: a new declaration form, allows general recursive functions to be
  4361 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4362 
  4363 * the constant for negation has been renamed from "not" to "Not" to
  4364 harmonize with FOL, ZF, LK, etc.;
  4365 
  4366 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4367 infinite lists;
  4368 
  4369 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4370 
  4371 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4372 problems in commutative rings, using axiomatic type classes for + and *;
  4373 
  4374 * more examples in HOL/MiniML and HOL/Auth;
  4375 
  4376 * more default rewrite rules for quantifiers, union/intersection;
  4377 
  4378 * a new constant `arbitrary == @x.False';
  4379 
  4380 * HOLCF/IOA replaces old HOL/IOA;
  4381 
  4382 * HOLCF changes: derived all rules and arities
  4383   + axiomatic type classes instead of classes
  4384   + typedef instead of faking type definitions
  4385   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4386   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4387   + eliminated the types void, one, tr
  4388   + use unit lift and bool lift (with translations) instead of one and tr
  4389   + eliminated blift from Lift3.thy (use Def instead of blift)
  4390   all eliminated rules are derived as theorems --> no visible changes ;
  4391 
  4392 
  4393 *** ZF ***
  4394 
  4395 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4396 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4397 as ZF_cs addSIs [equalityI];
  4398 
  4399 
  4400 
  4401 New in Isabelle94-7 (November 96)
  4402 ---------------------------------
  4403 
  4404 * allowing negative levels (as offsets) in prlev and choplev;
  4405 
  4406 * super-linear speedup for large simplifications;
  4407 
  4408 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4409 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4410 FAIL); can suppress it using the command Delsimps (ex_simps @
  4411 all_simps); De Morgan laws are also now included, by default;
  4412 
  4413 * improved printing of ==>  :  ~:
  4414 
  4415 * new object-logic "Sequents" adds linear logic, while replacing LK
  4416 and Modal (thanks to Sara Kalvala);
  4417 
  4418 * HOL/Auth: correctness proofs for authentication protocols;
  4419 
  4420 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4421 examples on HOL/Auth);
  4422 
  4423 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4424 the rewriter and classical reasoner simultaneously;
  4425 
  4426 * function uresult no longer returns theorems in "standard" format;
  4427 regain previous version by: val uresult = standard o uresult;
  4428 
  4429 
  4430 
  4431 New in Isabelle94-6
  4432 -------------------
  4433 
  4434 * oracles -- these establish an interface between Isabelle and trusted
  4435 external reasoners, which may deliver results as theorems;
  4436 
  4437 * proof objects (in particular record all uses of oracles);
  4438 
  4439 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4440 
  4441 * "constdefs" section in theory files;
  4442 
  4443 * "primrec" section (HOL) no longer requires names;
  4444 
  4445 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4446 
  4447 
  4448 
  4449 New in Isabelle94-5
  4450 -------------------
  4451 
  4452 * reduced space requirements;
  4453 
  4454 * automatic HTML generation from theories;
  4455 
  4456 * theory files no longer require "..." (quotes) around most types;
  4457 
  4458 * new examples, including two proofs of the Church-Rosser theorem;
  4459 
  4460 * non-curried (1994) version of HOL is no longer distributed;
  4461 
  4462 
  4463 
  4464 New in Isabelle94-4
  4465 -------------------
  4466 
  4467 * greatly reduced space requirements;
  4468 
  4469 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4470 
  4471 * searchable theorem database (see the section "Retrieving theorems" on
  4472 page 8 of the Reference Manual);
  4473 
  4474 * new examples, including Grabczewski's monumental case study of the
  4475 Axiom of Choice;
  4476 
  4477 * The previous version of HOL renamed to Old_HOL;
  4478 
  4479 * The new version of HOL (previously called CHOL) uses a curried syntax
  4480 for functions.  Application looks like f a b instead of f(a,b);
  4481 
  4482 * Mutually recursive inductive definitions finally work in HOL;
  4483 
  4484 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4485 translates to the operator "split";
  4486 
  4487 
  4488 
  4489 New in Isabelle94-3
  4490 -------------------
  4491 
  4492 * new infix operator, addss, allowing the classical reasoner to
  4493 perform simplification at each step of its search.  Example:
  4494         fast_tac (cs addss ss)
  4495 
  4496 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4497 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4498 look like (a,b) instead of <a,b>;
  4499 
  4500 * PLEASE NOTE: CHOL will eventually replace HOL!
  4501 
  4502 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4503 It translates to the operator "split".  A new theory of integers is available;
  4504 
  4505 * In ZF, integer numerals now denote two's-complement binary integers.
  4506 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4507 
  4508 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4509 of the Axiom of Choice;
  4510 
  4511 
  4512 
  4513 New in Isabelle94-2
  4514 -------------------
  4515 
  4516 * Significantly faster resolution;
  4517 
  4518 * the different sections in a .thy file can now be mixed and repeated
  4519 freely;
  4520 
  4521 * Database of theorems for FOL, HOL and ZF.  New
  4522 commands including qed, qed_goal and bind_thm store theorems in the database.
  4523 
  4524 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4525 a given theory (thms_of), or find out what theory a theorem was proved in
  4526 (theory_of_thm);
  4527 
  4528 * Bugs fixed in the inductive definition and datatype packages;
  4529 
  4530 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4531 and HOL_dup_cs obsolete;
  4532 
  4533 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4534 have been removed;
  4535 
  4536 * Simpler definition of function space in ZF;
  4537 
  4538 * new results about cardinal and ordinal arithmetic in ZF;
  4539 
  4540 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4541 types;
  4542 
  4543 
  4544 $Id$