NEWS
author wenzelm
Fri Jan 19 22:14:23 2007 +0100 (2007-01-19)
changeset 22125 cc35c948f6c5
parent 21960 0574f192b78a
child 22126 420b7b102acc
permissions -rw-r--r--
tuned;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: some popular names (e.g. "class", "fun", "help",
    19 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    20 
    21 * Legacy goal package: reduced interface to the bare minimum required
    22 to keep existing proof scripts running.  Most other user-level
    23 functions are now part of the OldGoals structure, which is *not* open
    24 by default (consider isatool expandshort before open OldGoals).
    25 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    26 these tend to cause confusion about the actual goal (!) context being
    27 used here, which is not necessarily the same as the_context().
    28 
    29 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    30 
    31 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    32 by default, which means that "prems" (and also "fixed variables") are
    33 suppressed from proof state output.  Note that the ProofGeneral
    34 settings mechanism allows to change and save options persistently, but
    35 older versions of Isabelle will fail to start up if a negative prems
    36 limit is imposed.
    37 
    38 * Local theory targets may be specified by non-nested blocks of
    39 ``context/locale/class ... begin'' followed by ``end''.  The body may
    40 contain definitions, theorems etc., including any derived mechanism
    41 that has been implemented on top of these primitives.  This concept
    42 generalizes the existing ``theorem (in ...)'' towards more versatility
    43 and scalability.
    44 
    45 * Proof General interface: proper undo of final 'end' command;
    46 discontinued Isabelle/classic mode (ML proof scripts).
    47 
    48 
    49 *** Document preparation ***
    50 
    51 * Added antiquotation @{theory name} which prints the given name,
    52 after checking that it refers to a valid ancestor theory in the
    53 current context.
    54 
    55 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    56 check the given source text as ML type/structure, printing verbatim.
    57 
    58 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    59 "c args == rhs" given in the current context.  (Any number of
    60 arguments may be given on the LHS.)
    61 
    62 
    63 
    64 *** Pure ***
    65 
    66 * class_package.ML offers a combination of axclasses and locales to
    67 achieve Haskell-like type classes in Isabelle. See
    68 HOL/ex/Classpackage.thy for examples.
    69 
    70 * Yet another code generator framework allows to generate executable
    71 code for ML and Haskell (including "class"es). A short usage sketch:
    72 
    73     internal compilation:
    74         code_gen <list of constants (term syntax)> (SML #)
    75     writing SML code to a file:
    76         code_gen <list of constants (term syntax)> (SML <filename>)
    77     writing Haskell code to a bunch of files:
    78         code_gen <list of constants (term syntax)> (Haskell <filename>)
    79 
    80 Reasonable default setup of framework in HOL/Main.
    81 
    82 See HOL/ex/Code*.thy for examples.
    83 
    84 Theorem attributs for selecting and transforming function equations theorems:
    85 
    86     [code fun]:       select a theorem as function equation for a specific constant
    87     [code nofun]:     deselect a theorem as function equation for a specific constant
    88     [code inline]:    select an equation theorem for unfolding (inlining) in place
    89     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    90 
    91 User-defined serializations (target in {SML, Haskell}):
    92 
    93     code_const <and-list of constants (term syntax)>
    94       {(target) <and-list of const target syntax>}+
    95 
    96     code_type <and-list of type constructors>
    97       {(target) <and-list of type target syntax>}+
    98 
    99     code_instance <and-list of instances>
   100       {(target)}+
   101         where instance ::= <type constructor> :: <class>
   102 
   103     code_class <and_list of classes>
   104       {(target) <and-list of class target syntax>}+
   105         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   106 
   107 For code_instance and code_class, target SML is silently ignored.
   108 
   109 See HOL theories and HOL/ex/Code*.thy for usage examples.  Doc/Isar/Advanced/Codegen/
   110 provides a tutorial.
   111 
   112 * Command 'no_translations' removes translation rules from theory
   113 syntax.
   114 
   115 * Overloaded definitions are now actually checked for acyclic
   116 dependencies.  The overloading scheme is slightly more general than
   117 that of Haskell98, although Isabelle does not demand an exact
   118 correspondence to type class and instance declarations.
   119 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   120 exotic versions of overloading -- at the discretion of the user!
   121 
   122 Polymorphic constants are represented via type arguments, i.e. the
   123 instantiation that matches an instance against the most general
   124 declaration given in the signature.  For example, with the declaration
   125 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   126 as c(nat).  Overloading is essentially simultaneous structural
   127 recursion over such type arguments.  Incomplete specification patterns
   128 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   129 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   130 Command 'print_theory' outputs the normalized system of recursive
   131 equations, see section "definitions".
   132 
   133 * Isar: improper proof element 'guess' is like 'obtain', but derives
   134 the obtained context from the course of reasoning!  For example:
   135 
   136   assume "EX x y. A x & B y"   -- "any previous fact"
   137   then guess x and y by clarify
   138 
   139 This technique is potentially adventurous, depending on the facts and
   140 proof tools being involved here.
   141 
   142 * Isar: known facts from the proof context may be specified as literal
   143 propositions, using ASCII back-quote syntax.  This works wherever
   144 named facts used to be allowed so far, in proof commands, proof
   145 methods, attributes etc.  Literal facts are retrieved from the context
   146 according to unification of type and term parameters.  For example,
   147 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   148 theorems in the current context, then these are valid literal facts:
   149 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   150 
   151 There is also a proof method "fact" which does the same composition
   152 for explicit goal states, e.g. the following proof texts coincide with
   153 certain special cases of literal facts:
   154 
   155   have "A" by fact                 ==  note `A`
   156   have "A ==> B" by fact           ==  note `A ==> B`
   157   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   158   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   159 
   160 * Isar: ":" (colon) is no longer a symbolic identifier character in
   161 outer syntax.  Thus symbolic identifiers may be used without
   162 additional white space in declarations like this: ``assume *: A''.
   163 
   164 * Isar: 'print_facts' prints all local facts of the current context,
   165 both named and unnamed ones.
   166 
   167 * Isar: 'def' now admits simultaneous definitions, e.g.:
   168 
   169   def x == "t" and y == "u"
   170 
   171 * Isar: added command 'unfolding', which is structurally similar to
   172 'using', but affects both the goal state and facts by unfolding given
   173 rewrite rules.  Thus many occurrences of the 'unfold' method or
   174 'unfolded' attribute may be replaced by first-class proof text.
   175 
   176 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   177 and command 'unfolding' now all support object-level equalities
   178 (potentially conditional).  The underlying notion of rewrite rule is
   179 analogous to the 'rule_format' attribute, but *not* that of the
   180 Simplifier (which is usually more generous).
   181 
   182 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   183 method expression within a sandbox consisting of the first N
   184 sub-goals, which need to exist.  For example, ``simp_all [3]''
   185 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   186 simplifies all new goals that emerge from applying rule foo to the
   187 originally first one.
   188 
   189 * Isar: schematic goals are no longer restricted to higher-order
   190 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   191 expected.
   192 
   193 * Isar: the conclusion of a long theorem statement is now either
   194 'shows' (a simultaneous conjunction, as before), or 'obtains'
   195 (essentially a disjunction of cases with local parameters and
   196 assumptions).  The latter allows to express general elimination rules
   197 adequately; in this notation common elimination rules look like this:
   198 
   199   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   200     assumes "EX x. P x"
   201     obtains x where "P x"
   202 
   203   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   204     assumes "A & B"
   205     obtains A and B
   206 
   207   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   208     assumes "A | B"
   209     obtains
   210       A
   211     | B
   212 
   213 The subsequent classical rules even refer to the formal "thesis"
   214 explicitly:
   215 
   216   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   217     obtains "~ thesis"
   218 
   219   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   220     obtains "thesis ==> something"
   221 
   222 The actual proof of an 'obtains' statement is analogous to that of the
   223 Isar proof element 'obtain', only that there may be several cases.
   224 Optional case names may be specified in parentheses; these will be
   225 available both in the present proof and as annotations in the
   226 resulting rule, for later use with the 'cases' method (cf. attribute
   227 case_names).
   228 
   229 * Isar: the assumptions of a long theorem statement are available as
   230 "assms" fact in the proof context.  This is more appropriate than the
   231 (historical) "prems", which refers to all assumptions of the current
   232 context, including those from the target locale, proof body etc.
   233 
   234 * Isar: 'print_statement' prints theorems from the current theory or
   235 proof context in long statement form, according to the syntax of a
   236 top-level lemma.
   237 
   238 * Isar: 'obtain' takes an optional case name for the local context
   239 introduction rule (default "that").
   240 
   241 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   242 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   243 to occur.
   244 
   245 * Pure: syntax "CONST name" produces a fully internalized constant
   246 according to the current context.  This is particularly useful for
   247 syntax translations that should refer to internal constant
   248 representations independently of name spaces.
   249 
   250 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   251 instead of "FOO ". This allows multiple binder declarations to coexist
   252 in the same context.  INCOMPATIBILITY.
   253 
   254 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   255 primitive that also works in a locale context (both for constants and
   256 fixed variables).  Type declaration and internal syntactic
   257 representation of given constants retrieved from the context.
   258 
   259 * Isar/locales: new derived specification elements 'axiomatization',
   260 'definition', 'abbreviation', which support type-inference, admit
   261 object-level specifications (equality, equivalence).  See also the
   262 isar-ref manual.  Examples:
   263 
   264   axiomatization
   265     eq  (infix "===" 50) where
   266     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   267 
   268   definition "f x y = x + y + 1"
   269   definition g where "g x = f x x"
   270 
   271   abbreviation
   272     neq  (infix "=!=" 50) where
   273     "x =!= y == ~ (x === y)"
   274 
   275 These specifications may be also used in a locale context.  Then the
   276 constants being introduced depend on certain fixed parameters, and the
   277 constant name is qualified by the locale base name.  An internal
   278 abbreviation takes care for convenient input and output, making the
   279 parameters implicit and using the original short name.  See also
   280 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   281 entities from a monomorphic theory.
   282 
   283 Presently, abbreviations are only available 'in' a target locale, but
   284 not inherited by general import expressions.  Also note that
   285 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   286 'translations' in common applications.
   287 
   288 Concrete syntax is attached to specified constants in internal form,
   289 independently of name spaces.  The parse tree representation is
   290 slightly different -- use 'notation' instead of raw 'syntax', and
   291 'translations' with explicit "CONST" markup to accommodate this.
   292 
   293 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   294 the current context.  Print mode "no_abbrevs" prevents inversion of
   295 abbreviations on output.
   296 
   297 * Isar/locales: improved parameter handling:
   298 - use of locales "var" and "struct" no longer necessary;
   299 - parameter renamings are no longer required to be injective.
   300   This enables, for example, to define a locale for endomorphisms thus:
   301   locale endom = homom mult mult h.
   302 
   303 * Isar/locales: changed the way locales with predicates are defined.
   304 Instead of accumulating the specification, the imported expression is
   305 now an interpretation.
   306 INCOMPATIBILITY: different normal form of locale expressions.
   307 In particular, in interpretations of locales with predicates,
   308 goals repesenting already interpreted fragments are not removed
   309 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   310 
   311 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   312 backward reasoning on locales predicates.  The methods are aware of
   313 interpretations and discharge corresponding goals.  `intro_locales' is
   314 less aggressive then `unfold_locales' and does not unfold predicates to
   315 assumptions.
   316 
   317 * Isar/locales: the order in which locale fragments are accumulated
   318 has changed.  This enables to override declarations from fragments
   319 due to interpretations -- for example, unwanted simp rules.
   320 
   321 * Provers/induct: improved internal context management to support
   322 local fixes and defines on-the-fly.  Thus explicit meta-level
   323 connectives !! and ==> are rarely required anymore in inductive goals
   324 (using object-logic connectives for this purpose has been long
   325 obsolete anyway).  The subsequent proof patterns illustrate advanced
   326 techniques of natural induction; general datatypes and inductive sets
   327 work analogously (see also src/HOL/Lambda for realistic examples).
   328 
   329 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   330 parameters:
   331 
   332   lemma
   333     fixes n :: nat and x :: 'a
   334     assumes a: "A n x"
   335     shows "P n x"
   336     using a                     -- {* make induct insert fact a *}
   337   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   338     case 0
   339     show ?case sorry
   340   next
   341     case (Suc n)
   342     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   343     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   344     show ?case sorry
   345   qed
   346 
   347 (2) This is how to perform induction over ``expressions of a certain
   348 form'', using a locally defined inductive parameter n == "a x"
   349 together with strengthening (the latter is usually required to get
   350 sufficiently flexible induction hypotheses):
   351 
   352   lemma
   353     fixes a :: "'a => nat"
   354     assumes a: "A (a x)"
   355     shows "P (a x)"
   356     using a
   357   proof (induct n == "a x" arbitrary: x)
   358     ...
   359 
   360 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   361 particular technique.
   362 
   363 (3) This is how to perform existential reasoning ('obtains' or
   364 'obtain') by induction, while avoiding explicit object-logic
   365 encodings:
   366 
   367   lemma
   368     fixes n :: nat
   369     obtains x :: 'a where "P n x" and "Q n x"
   370   proof (induct n arbitrary: thesis)
   371     case 0
   372     obtain x where "P 0 x" and "Q 0 x" sorry
   373     then show thesis by (rule 0)
   374   next
   375     case (Suc n)
   376     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   377     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   378     then show thesis by (rule Suc.prems)
   379   qed
   380 
   381 Here the 'arbitrary: thesis' specification essentially modifies the
   382 scope of the formal thesis parameter, in order to the get the whole
   383 existence statement through the induction as expected.
   384 
   385 * Provers/induct: mutual induction rules are now specified as a list
   386 of rule sharing the same induction cases.  HOL packages usually
   387 provide foo_bar.inducts for mutually defined items foo and bar
   388 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   389 specify mutual induction rules differently, i.e. like this:
   390 
   391   (induct rule: foo_bar.inducts)
   392   (induct set: foo bar)
   393   (induct type: foo bar)
   394 
   395 The ML function ProjectRule.projections turns old-style rules into the
   396 new format.
   397 
   398 * Provers/induct: improved handling of simultaneous goals.  Instead of
   399 introducing object-level conjunction, the statement is now split into
   400 several conclusions, while the corresponding symbolic cases are
   401 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   402 explicitly.  For example:
   403 
   404   lemma
   405     fixes n :: nat
   406     shows "P n" and "Q n"
   407   proof (induct n)
   408     case 0 case 1
   409     show "P 0" sorry
   410   next
   411     case 0 case 2
   412     show "Q 0" sorry
   413   next
   414     case (Suc n) case 1
   415     note `P n` and `Q n`
   416     show "P (Suc n)" sorry
   417   next
   418     case (Suc n) case 2
   419     note `P n` and `Q n`
   420     show "Q (Suc n)" sorry
   421   qed
   422 
   423 The split into subcases may be deferred as follows -- this is
   424 particularly relevant for goal statements with local premises.
   425 
   426   lemma
   427     fixes n :: nat
   428     shows "A n ==> P n" and "B n ==> Q n"
   429   proof (induct n)
   430     case 0
   431     {
   432       case 1
   433       note `A 0`
   434       show "P 0" sorry
   435     next
   436       case 2
   437       note `B 0`
   438       show "Q 0" sorry
   439     }
   440   next
   441     case (Suc n)
   442     note `A n ==> P n` and `B n ==> Q n`
   443     {
   444       case 1
   445       note `A (Suc n)`
   446       show "P (Suc n)" sorry
   447     next
   448       case 2
   449       note `B (Suc n)`
   450       show "Q (Suc n)" sorry
   451     }
   452   qed
   453 
   454 If simultaneous goals are to be used with mutual rules, the statement
   455 needs to be structured carefully as a two-level conjunction, using
   456 lists of propositions separated by 'and':
   457 
   458   lemma
   459     shows "a : A ==> P1 a"
   460           "a : A ==> P2 a"
   461       and "b : B ==> Q1 b"
   462           "b : B ==> Q2 b"
   463           "b : B ==> Q3 b"
   464   proof (induct set: A B)
   465 
   466 * Provers/induct: support coinduction as well.  See
   467 src/HOL/Library/Coinductive_List.thy for various examples.
   468 
   469 * Attribute "symmetric" produces result with standardized schematic
   470 variables (index 0).  Potential INCOMPATIBILITY.
   471 
   472 * Simplifier: by default the simplifier trace only shows top level rewrites
   473 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   474 less danger of being flooded by the trace. The trace indicates where parts
   475 have been suppressed.
   476   
   477 * Provers/classical: removed obsolete classical version of elim_format
   478 attribute; classical elim/dest rules are now treated uniformly when
   479 manipulating the claset.
   480 
   481 * Provers/classical: stricter checks to ensure that supplied intro,
   482 dest and elim rules are well-formed; dest and elim rules must have at
   483 least one premise.
   484 
   485 * Provers/classical: attributes dest/elim/intro take an optional
   486 weight argument for the rule (just as the Pure versions).  Weights are
   487 ignored by automated tools, but determine the search order of single
   488 rule steps.
   489 
   490 * Syntax: input syntax now supports dummy variable binding "%_. b",
   491 where the body does not mention the bound variable.  Note that dummy
   492 patterns implicitly depend on their context of bounds, which makes
   493 "{_. _}" match any set comprehension as expected.  Potential
   494 INCOMPATIBILITY -- parse translations need to cope with syntactic
   495 constant "_idtdummy" in the binding position.
   496 
   497 * Syntax: removed obsolete syntactic constant "_K" and its associated
   498 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   499 for example "A -> B" => "Pi A (%_. B)".
   500 
   501 * Pure: 'class_deps' command visualizes the subclass relation, using
   502 the graph browser tool.
   503 
   504 * Pure: 'print_theory' now suppresses entities with internal name
   505 (trailing "_") by default; use '!' option for full details.
   506 
   507 
   508 *** HOL ***
   509 
   510 * New syntactic class "size"; overloaded constant "size" now
   511 has type "'a::size ==> bool"
   512 
   513 * Constants "Divides.op div", "Divides.op mod" and "Divides.op dvd" no named
   514   "Divides.div", "Divides.mod" and "Divides.dvd"
   515   INCOMPATIBILITY for ML code directly refering to constant names.
   516 
   517 * Replaced "auto_term" by the conceptually simpler method "relation",
   518 which just applies the instantiated termination rule with no further
   519 simplifications.
   520 INCOMPATIBILITY: 
   521 Replace 
   522         termination by (auto_term "MYREL")
   523 with 
   524         termination by (relation "MYREL") auto
   525 
   526 * Automated termination proofs "by lexicographic_order" are now
   527 included in the abbreviated function command "fun". No explicit
   528 "termination" command is necessary anymore.
   529 INCOMPATIBILITY: If a "fun"-definition cannot be proved terminating by
   530 a lexicographic size order, then the command fails. Use the expanded
   531 version "function" for these cases.
   532 
   533 * New method "lexicographic_order" automatically synthesizes
   534 termination relations as lexicographic combinations of size measures. 
   535 Usage for (function package) termination proofs:
   536 
   537 termination 
   538 by lexicographic_order
   539 
   540 * Records: generalised field-update to take a function on the field 
   541 rather than the new value: r(|A := x|) is translated to A_update (K x) r
   542 The K-combinator that is internally used is called K_record.
   543 INCOMPATIBILITY: Usage of the plain update functions has to be
   544 adapted.
   545  
   546 * axclass "semiring_0" now contains annihilation axioms 
   547 ("x * 0 = 0","0 * x = 0"), which are required for a semiring. Richer 
   548 structures do not inherit from semiring_0 anymore, because this property 
   549 is a theorem there, not an axiom.
   550 INCOMPATIBILITY: In instances of semiring_0, there is more to prove, but 
   551 this is mostly trivial.
   552 
   553 * axclass "recpower" was generalized to arbitrary monoids, not just 
   554 commutative semirings.
   555 INCOMPATIBILITY: If you use recpower and need commutativity or a semiring
   556 property, add the corresponding classes.
   557 
   558 * Locale Lattic_Locales.partial_order changed (to achieve consistency with
   559 axclass order):
   560 - moved to Orderings.partial_order
   561 - additional parameter ``less''
   562 INCOMPATIBILITY.
   563 
   564 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   565 INCOMPATIBILITY: translations containing list_all2 may go wrong. On Isar
   566 level, use abbreviations instead.
   567 
   568 * Constant "List.op mem" in List.thy now has proper name: "List.memberl"
   569 INCOMPATIBILITY: rarely occuring name references (e.g. ``List.op mem.simps'')
   570 require renaming (e.g. ``List.memberl.simps'').
   571 
   572 * Renamed constants in HOL.thy:
   573     0      ~> HOL.zero
   574     1      ~> HOL.one
   575 INCOMPATIBILITY: ML code directly refering to constant names may need adaption
   576 This in general only affects hand-written proof tactics, simprocs and so on.
   577 
   578 * New theory Code_Generator providing class 'eq',
   579 allowing for code generation with polymorphic equality.
   580 
   581 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has been
   582 abandoned in favour of plain 'int'. INCOMPATIBILITY -- Significant changes
   583 for setting up numeral syntax for types:
   584 
   585   - new constants Numeral.pred and Numeral.succ instead
   586       of former Numeral.bin_pred and Numeral.bin_succ.
   587   - Use integer operations instead of bin_add, bin_mult and so on.
   588   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   589   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   590 
   591 See HOL/Integ/IntArith.thy for an example setup.
   592 
   593 * New top level command 'normal_form' computes the normal form of a term
   594 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   595 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   596 because the functions are compiled to ML first.
   597 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   598 an identifier.
   599 
   600 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   601 25 like -->); output depends on the "iff" print_mode, the default is
   602 "A = B" (with priority 50).
   603 
   604 * Renamed constants in HOL.thy and Orderings.thy:
   605     op +   ~> HOL.plus
   606     op -   ~> HOL.minus
   607     uminus ~> HOL.uminus
   608     op *   ~> HOL.times
   609     op <   ~> Orderings.less
   610     op <=  ~> Orderings.less_eq
   611 
   612 Adaptions may be required in the following cases:
   613 
   614 a) User-defined constants using any of the names "plus", "minus", "times",
   615 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   616 may go wrong.
   617 INCOMPATIBILITY: use more specific names.
   618 
   619 b) Variables named "plus", "minus", "times", "less", "less_eq"
   620 INCOMPATIBILITY: use more specific names.
   621 
   622 c) Permutative equations (e.g. "a + b = b + a")
   623 Since the change of names also changes the order of terms, permutative
   624 rewrite rules may get applied in a different order. Experience shows that
   625 this is rarely the case (only two adaptions in the whole Isabelle
   626 distribution).
   627 INCOMPATIBILITY: rewrite proofs
   628 
   629 d) ML code directly refering to constant names
   630 This in general only affects hand-written proof tactics, simprocs and so on.
   631 INCOMPATIBILITY: grep your sourcecode and replace names.
   632 
   633 * Relations less (<) and less_eq (<=) are also available on type bool.
   634 Modified syntax to disallow nesting without explicit parentheses,
   635 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   636 
   637 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   638 
   639 * Relation composition operator "op O" now has precedence 75 and binds
   640 stronger than union and intersection. INCOMPATIBILITY.
   641 
   642 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   643   Use "{m..<n}" (and relatives) instead.
   644 
   645 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   646 "t = s" to False (by simproc "neq_simproc").  For backward
   647 compatibility this can be disabled by ML "reset use_neq_simproc".
   648 
   649 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   650 
   651 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   652 
   653 * Theorem setsum_mult renamed to setsum_right_distrib.
   654 
   655 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   656 'rule' method.
   657 
   658 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   659 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   660 "=" on type bool) are handled, variable names of the form "lit_<n>"
   661 are no longer reserved, significant speedup.
   662 
   663 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   664 still supported as well.
   665 
   666 * inductive and datatype: provide projections of mutual rules, bundled
   667 as foo_bar.inducts;
   668 
   669 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to Library.
   670 
   671 * Library: moved theory Accessible_Part to main HOL.
   672 
   673 * Library: added theory Coinductive_List of potentially infinite lists
   674 as greatest fixed-point.
   675 
   676 * Library: added theory AssocList which implements (finite) maps as
   677 association lists.
   678 
   679 * New proof method "evaluation" for efficiently solving a goal (i.e. a
   680 boolean expression) by compiling it to ML. The goal is "proved" (via
   681 the oracle "Evaluation") if it evaluates to True.
   682 
   683 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   684 also when invoked by the simplifier.  This results in the simplifier
   685 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   686 fast_arith_split_limit to 0 to obtain the old behavior.
   687 
   688 * Support for hex (0x20) and binary (0b1001) numerals. 
   689 
   690 * New method: reify eqs (t), where eqs are equations for an
   691 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   692 parameter, computes a term s::'b and a list xs::'a list and proves the
   693 theorem I xs s = t. This is also known as reification or quoting. The
   694 resulting theorem is applied to the subgoal to substitute t with I xs
   695 s.  If t is omitted, the subgoal itself is reified.
   696 
   697 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   698 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   699 where f is supposed to be a computable function (in the sense of code
   700 generattion). The method uses reify to compute s and xs as above then
   701 applies corr_thm and uses normalization by evaluation to "prove" f s =
   702 r and finally gets the theorem t = r, which is again applied to the
   703 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   704 
   705 * Reflection: Automatic refification now handels binding, an example
   706 is available in HOL/ex/ReflectionEx.thy
   707 
   708 
   709 *** HOL-Algebra ***
   710 
   711 * Formalisation of ideals and the quotient construction over rings.
   712 
   713 * Order and lattice theory no longer based on records.
   714 INCOMPATIBILITY.
   715 
   716 * Renamed lemmas least_carrier -> least_closed and
   717 greatest_carrier -> greatest_closed.  INCOMPATIBILITY.
   718 
   719 * Method algebra is now set up via an attribute.  For examples see
   720 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   721 of algebraic structures.
   722 
   723 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.
   724 
   725 
   726 *** HOL-Complex ***
   727 
   728 * Theory Real: new method ferrack implements quantifier elimination
   729 for linear arithmetic over the reals. The quantifier elimination
   730 feature is used only for decision, for compatibility with arith. This
   731 means a goal is either solved or left unchanged, no simplification.
   732 
   733 * Real: New axiomatic classes formalize real normed vector spaces and
   734 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   735 and norm :: 'a => real.
   736 
   737 * Real: New constant of_real :: real => 'a::real_algebra_1 injects from
   738 reals into other types. The overloaded constant Reals :: 'a set is now
   739 defined as range of_real; potential INCOMPATIBILITY.
   740 
   741 * Hyperreal: Several constants that previously worked only for the reals
   742 have been generalized, so they now work over arbitrary vector spaces. Type
   743 annotations may need to be added in some cases; potential INCOMPATIBILITY.
   744 
   745   Infinitesimal  :: ('a::real_normed_vector) star set"
   746   HFinite        :: ('a::real_normed_vector) star set"
   747   HInfinite      :: ('a::real_normed_vector) star set"
   748   approx         :: ('a::real_normed_vector) star => 'a star => bool
   749   monad          :: ('a::real_normed_vector) star => 'a star set
   750   galaxy         :: ('a::real_normed_vector) star => 'a star set
   751   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   752   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   753   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   754   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   755   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   756   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   757   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   758 
   759 * Complex: Some complex-specific constants are now abbreviations for
   760 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod = hnorm.
   761 Other constants have been entirely removed in favor of the polymorphic
   762 versions (INCOMPATIBILITY):
   763 
   764   approx        <-- capprox
   765   HFinite       <-- CFinite
   766   HInfinite     <-- CInfinite
   767   Infinitesimal <-- CInfinitesimal
   768   monad         <-- cmonad
   769   galaxy        <-- cgalaxy
   770   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   771   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   772   (ns)deriv     <-- (ns)cderiv
   773 
   774 
   775 *** ML ***
   776 
   777 * Pure/table:
   778 
   779 Function `...tab.foldl` removed.
   780 INCOMPATIBILITY: use `...tabfold` instead
   781 
   782 * Pure/library:
   783 
   784 `gen_rem(s)` abandoned in favour of `remove` / `subtract`.
   785 INCOMPATIBILITY:
   786 rewrite "gen_rem eq (xs, x)" to "remove (eq o swap) x xs"
   787 rewrite "gen_rems eq (xs, ys)" to "subtract (eq o swap) ys xs"
   788 drop "swap" if "eq" is symmetric.
   789 
   790 * Pure/library:
   791 
   792 infixes `ins` `ins_string` `ins_int` have been abandoned in favour of `insert`.
   793 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"
   794 
   795 * Pure/General/susp.ML:
   796 
   797 New module for delayed evaluations.
   798 
   799 * Pure/library:
   800 
   801 Semantically identical functions "equal_list" and "eq_list" have been
   802 unified to "eq_list".
   803 
   804 * Pure/library:
   805 
   806   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   807   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   808 
   809 The semantics of "burrow" is: "take a function with *simulatanously*
   810 transforms a list of value, and apply it *simulatanously* to a list of
   811 list of values of the appropriate type". Confer this with "map" which
   812 would *not* apply its argument function simulatanously but in
   813 sequence. "fold_burrow" has an additional context.
   814 
   815 Both actually avoid the usage of "unflat" since they hide away
   816 "unflat" from the user.
   817 
   818 * Pure/library: functions map2 and fold2 with curried syntax for
   819 simultanous mapping and folding:
   820 
   821     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   822     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   823 
   824 * Pure/library: indexed lists - some functions in the Isabelle library
   825 treating lists over 'a as finite mappings from [0...n] to 'a have been
   826 given more convenient names and signatures reminiscent of similar
   827 functions for alists, tables, etc:
   828 
   829   val nth: 'a list -> int -> 'a 
   830   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   831   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   832 
   833 Note that fold_index starts counting at index 0, not 1 like foldln
   834 used to.
   835 
   836 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   837 
   838 * Pure/General/name_mangler.ML provides a functor for generic name
   839 mangling (bijective mapping from expression values to strings).
   840 
   841 * Pure/General/rat.ML implements rational numbers.
   842 
   843 * Pure/General/table.ML: the join operations now works via exceptions
   844 DUP/SAME instead of type option.  This is simpler in simple cases, and
   845 admits slightly more efficient complex applications.
   846 
   847 * Pure: datatype Context.generic joins theory/Proof.context and
   848 provides some facilities for code that works in either kind of
   849 context, notably GenericDataFun for uniform theory and proof data.
   850 
   851 * Pure: 'advanced' translation functions (parse_translation etc.) now
   852 use Context.generic instead of just theory.
   853 
   854 * Pure: simplified internal attribute type, which is now always
   855 Context.generic * thm -> Context.generic * thm.  Global (theory)
   856 vs. local (Proof.context) attributes have been discontinued, while
   857 minimizing code duplication.  Thm.rule_attribute and
   858 Thm.declaration_attribute build canonical attributes; see also
   859 structure Context for further operations on Context.generic, notably
   860 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   861 declarations and definitions.
   862 
   863 * Pure/kernel: consts certification ignores sort constraints given in
   864 signature declarations.  (This information is not relevant to the
   865 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   866 
   867 * Pure: axiomatic type classes are now purely definitional, with
   868 explicit proofs of class axioms and super class relations performed
   869 internally.  See Pure/axclass.ML for the main internal interfaces --
   870 notably AxClass.define_class supercedes AxClass.add_axclass, and
   871 AxClass.axiomatize_class/classrel/arity supercede
   872 Sign.add_classes/classrel/arities.
   873 
   874 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   875 global/local versions on theory vs. Proof.context have been
   876 discontinued; Attrib.syntax and Method.syntax have been adapted
   877 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   878 attributes, methods, etc.
   879 
   880 * Pure: several functions of signature "... -> theory -> theory * ..."
   881 have been reoriented to "... -> theory -> ... * theory" in order to
   882 allow natural usage in combination with the ||>, ||>>, |-> and
   883 fold_map combinators.
   884 
   885 * Pure: official theorem names (closed derivations) and additional
   886 comments (tags) are now strictly separate.  Name hints -- which are
   887 maintained as tags -- may be attached any time without affecting the
   888 derivation.
   889 
   890 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   891 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   892 achieve the old behaviour.
   893 
   894 * Pure: the "Goal" constant is now called "prop", supporting a
   895 slightly more general idea of ``protecting'' meta-level rule
   896 statements.
   897 
   898 * Pure: Logic.(un)varify only works in a global context, which is now
   899 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   900 Logic.legacy_(un)varify as temporary workaround.
   901 
   902 * Pure: structure Name provides scalable operations for generating
   903 internal variable names, notably Name.variants etc.  This replaces
   904 some popular functions from term.ML:
   905 
   906   Term.variant		->  Name.variant
   907   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   908   Term.invent_names	->  Name.invent_list
   909 
   910 Note that low-level renaming rarely occurs in new code -- operations
   911 from structure Variable are used instead (see below).
   912 
   913 * Pure: structure Variable provides fundamental operations for proper
   914 treatment of fixed/schematic variables in a context.  For example,
   915 Variable.import introduces fixes for schematics of given facts and
   916 Variable.export reverses the effect (up to renaming) -- this replaces
   917 various freeze_thaw operations.
   918 
   919 * Pure: structure Goal provides simple interfaces for
   920 init/conclude/finish and tactical prove operations (replacing former
   921 Tactic.prove).  Goal.prove is the canonical way to prove results
   922 within a given context; Goal.prove_global is a degraded version for
   923 theory level goals, including a global Drule.standard.  Note that
   924 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   925 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   926 in a locale context).
   927 
   928 * Isar: simplified treatment of user-level errors, using exception
   929 ERROR of string uniformly.  Function error now merely raises ERROR,
   930 without any side effect on output channels.  The Isar toplevel takes
   931 care of proper display of ERROR exceptions.  ML code may use plain
   932 handle/can/try; cat_error may be used to concatenate errors like this:
   933 
   934   ... handle ERROR msg => cat_error msg "..."
   935 
   936 Toplevel ML code (run directly or through the Isar toplevel) may be
   937 embedded into the Isar toplevel with exception display/debug like
   938 this:
   939 
   940   Isar.toplevel (fn () => ...)
   941 
   942 INCOMPATIBILITY, removed special transform_error facilities, removed
   943 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   944 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   945 -- use plain ERROR instead.
   946 
   947 * Isar: theory setup now has type (theory -> theory), instead of a
   948 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   949 
   950 * Isar: installed ML toplevel pretty printer for type Proof.context,
   951 subject to ProofContext.debug/verbose flags.
   952 
   953 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   954 theory before entering a proof state.  Transactions now always see a
   955 quasi-functional intermediate checkpoint, both in interactive and
   956 batch mode.
   957 
   958 * Simplifier: the simpset of a running simplification process now
   959 contains a proof context (cf. Simplifier.the_context), which is the
   960 very context that the initial simpset has been retrieved from (by
   961 simpset_of/local_simpset_of).  Consequently, all plug-in components
   962 (solver, looper etc.) may depend on arbitrary proof data.
   963 
   964 * Simplifier.inherit_context inherits the proof context (plus the
   965 local bounds) of the current simplification process; any simproc
   966 etc. that calls the Simplifier recursively should do this!  Removed
   967 former Simplifier.inherit_bounds, which is already included here --
   968 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   969 specify an explicit context using Simplifier.context/theory_context.
   970 
   971 * Simplifier/Classical Reasoner: more abstract interfaces
   972 change_simpset/claset for modifying the simpset/claset reference of a
   973 theory; raw versions simpset/claset_ref etc. have been discontinued --
   974 INCOMPATIBILITY.
   975 
   976 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   977 "Trueprop" etc.
   978 
   979 
   980 *** System ***
   981 
   982 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   983 locations -- now includes the Isabelle version identifier as well.
   984 This simplifies use of multiple Isabelle installations.
   985 
   986 * isabelle-process: option -S (secure mode) disables some critical
   987 operations, notably runtime compilation and evaluation of ML source
   988 code.
   989 
   990 
   991 New in Isabelle2005 (October 2005)
   992 ----------------------------------
   993 
   994 *** General ***
   995 
   996 * Theory headers: the new header syntax for Isar theories is
   997 
   998   theory <name>
   999   imports <theory1> ... <theoryN>
  1000   uses <file1> ... <fileM>
  1001   begin
  1002 
  1003 where the 'uses' part is optional.  The previous syntax
  1004 
  1005   theory <name> = <theory1> + ... + <theoryN>:
  1006 
  1007 will disappear in the next release.  Use isatool fixheaders to convert
  1008 existing theory files.  Note that there is no change in ancient
  1009 non-Isar theories now, but these will disappear soon.
  1010 
  1011 * Theory loader: parent theories can now also be referred to via
  1012 relative and absolute paths.
  1013 
  1014 * Command 'find_theorems' searches for a list of criteria instead of a
  1015 list of constants. Known criteria are: intro, elim, dest, name:string,
  1016 simp:term, and any term. Criteria can be preceded by '-' to select
  1017 theorems that do not match. Intro, elim, dest select theorems that
  1018 match the current goal, name:s selects theorems whose fully qualified
  1019 name contain s, and simp:term selects all simplification rules whose
  1020 lhs match term.  Any other term is interpreted as pattern and selects
  1021 all theorems matching the pattern. Available in ProofGeneral under
  1022 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1023 
  1024   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1025 
  1026 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1027 matching the current goal as introduction rule and not having "HOL."
  1028 in their name (i.e. not being defined in theory HOL).
  1029 
  1030 * Command 'thms_containing' has been discontinued in favour of
  1031 'find_theorems'; INCOMPATIBILITY.
  1032 
  1033 * Communication with Proof General is now 8bit clean, which means that
  1034 Unicode text in UTF-8 encoding may be used within theory texts (both
  1035 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1036 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1037 
  1038   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1039   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1040 
  1041 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1042 Classical Reasoner.  Typical big applications run around 2 times
  1043 faster.
  1044 
  1045 
  1046 *** Document preparation ***
  1047 
  1048 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1049 of raw sources.  Only those symbols that do not require additional
  1050 LaTeX packages (depending on comments in isabellesym.sty) are
  1051 displayed properly, everything else is left verbatim.  isatool display
  1052 and isatool print are used as front ends (these are subject to the
  1053 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1054 
  1055 * Command tags control specific markup of certain regions of text,
  1056 notably folding and hiding.  Predefined tags include "theory" (for
  1057 theory begin and end), "proof" for proof commands, and "ML" for
  1058 commands involving ML code; the additional tags "visible" and
  1059 "invisible" are unused by default.  Users may give explicit tag
  1060 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1061 interpretation of tags is determined by the LaTeX job during document
  1062 preparation: see option -V of isatool usedir, or options -n and -t of
  1063 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1064 \isadroptag.
  1065 
  1066 Several document versions may be produced at the same time via isatool
  1067 usedir (the generated index.html will link all of them).  Typical
  1068 specifications include ''-V document=theory,proof,ML'' to present
  1069 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1070 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1071 these parts without any formal replacement text.  The Isabelle site
  1072 default settings produce ''document'' and ''outline'' versions as
  1073 specified above.
  1074 
  1075 * Several new antiquotations:
  1076 
  1077   @{term_type term} prints a term with its type annotated;
  1078 
  1079   @{typeof term} prints the type of a term;
  1080 
  1081   @{const const} is the same as @{term const}, but checks that the
  1082   argument is a known logical constant;
  1083 
  1084   @{term_style style term} and @{thm_style style thm} print a term or
  1085   theorem applying a "style" to it
  1086 
  1087   @{ML text}
  1088 
  1089 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1090 definitions, equations, inequations etc., 'concl' printing only the
  1091 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1092 to print the specified premise.  TermStyle.add_style provides an ML
  1093 interface for introducing further styles.  See also the "LaTeX Sugar"
  1094 document practical applications.  The ML antiquotation prints
  1095 type-checked ML expressions verbatim.
  1096 
  1097 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1098 and 'text' support optional locale specification '(in loc)', which
  1099 specifies the default context for interpreting antiquotations.  For
  1100 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1101 
  1102 * Option 'locale=NAME' of antiquotations specifies an alternative
  1103 context interpreting the subsequent argument.  For example: @{thm
  1104 [locale=lattice] inf_assoc}.
  1105 
  1106 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1107 a proof context.
  1108 
  1109 * Proper output of antiquotations for theory commands involving a
  1110 proof context (such as 'locale' or 'theorem (in loc) ...').
  1111 
  1112 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1113 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1114 
  1115 * isatool usedir: new option -C (default true) controls whether option
  1116 -D should include a copy of the original document directory; -C false
  1117 prevents unwanted effects such as copying of administrative CVS data.
  1118 
  1119 
  1120 *** Pure ***
  1121 
  1122 * Considerably improved version of 'constdefs' command.  Now performs
  1123 automatic type-inference of declared constants; additional support for
  1124 local structure declarations (cf. locales and HOL records), see also
  1125 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1126 sequential dependencies of definitions within a single 'constdefs'
  1127 section; moreover, the declared name needs to be an identifier.  If
  1128 all fails, consider to fall back on 'consts' and 'defs' separately.
  1129 
  1130 * Improved indexed syntax and implicit structures.  First of all,
  1131 indexed syntax provides a notational device for subscripted
  1132 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1133 expressions.  Secondly, in a local context with structure
  1134 declarations, number indexes \<^sub>n or the empty index (default
  1135 number 1) refer to a certain fixed variable implicitly; option
  1136 show_structs controls printing of implicit structures.  Typical
  1137 applications of these concepts involve record types and locales.
  1138 
  1139 * New command 'no_syntax' removes grammar declarations (and
  1140 translations) resulting from the given syntax specification, which is
  1141 interpreted in the same manner as for the 'syntax' command.
  1142 
  1143 * 'Advanced' translation functions (parse_translation etc.) may depend
  1144 on the signature of the theory context being presently used for
  1145 parsing/printing, see also isar-ref manual.
  1146 
  1147 * Improved 'oracle' command provides a type-safe interface to turn an
  1148 ML expression of type theory -> T -> term into a primitive rule of
  1149 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1150 is already included here); see also FOL/ex/IffExample.thy;
  1151 INCOMPATIBILITY.
  1152 
  1153 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1154 before); "cI" is no longer bound, use "c.intro" instead.
  1155 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1156 axclasses vs. locales.
  1157 
  1158 * Improved internal renaming of symbolic identifiers -- attach primes
  1159 instead of base 26 numbers.
  1160 
  1161 * New flag show_question_marks controls printing of leading question
  1162 marks in schematic variable names.
  1163 
  1164 * In schematic variable names, *any* symbol following \<^isub> or
  1165 \<^isup> is now treated as part of the base name.  For example, the
  1166 following works without printing of awkward ".0" indexes:
  1167 
  1168   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1169     by simp
  1170 
  1171 * Inner syntax includes (*(*nested*) comments*).
  1172 
  1173 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1174 annotations as "(00...)".
  1175 
  1176 * Clear separation of logical types and nonterminals, where the latter
  1177 may only occur in 'syntax' specifications or type abbreviations.
  1178 Before that distinction was only partially implemented via type class
  1179 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1180 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1181 exotic syntax specifications may require further adaption
  1182 (e.g. Cube/Cube.thy).
  1183 
  1184 * Removed obsolete type class "logic", use the top sort {} instead.
  1185 Note that non-logical types should be declared as 'nonterminals'
  1186 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1187 specifications.
  1188 
  1189 * Attributes 'induct' and 'cases': type or set names may now be
  1190 locally fixed variables as well.
  1191 
  1192 * Simplifier: can now control the depth to which conditional rewriting
  1193 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1194 Limit.
  1195 
  1196 * Simplifier: simplification procedures may now take the current
  1197 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1198 interface), which is very useful for calling the Simplifier
  1199 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1200 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1201 low-level mk_simproc no longer applies Logic.varify internally, to
  1202 allow for use in a context of fixed variables.
  1203 
  1204 * thin_tac now works even if the assumption being deleted contains !!
  1205 or ==>.  More generally, erule now works even if the major premise of
  1206 the elimination rule contains !! or ==>.
  1207 
  1208 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1209 
  1210 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1211 from Pure, which contains all common declarations already.  Both
  1212 theories are defined via plain Isabelle/Isar .thy files.
  1213 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1214 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1215 use isatool fixcpure to adapt your theory and ML sources.
  1216 
  1217 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1218 selections of theorems in named facts via index ranges.
  1219 
  1220 * 'print_theorems': in theory mode, really print the difference
  1221 wrt. the last state (works for interactive theory development only),
  1222 in proof mode print all local facts (cf. 'print_facts');
  1223 
  1224 * 'hide': option '(open)' hides only base names.
  1225 
  1226 * More efficient treatment of intermediate checkpoints in interactive
  1227 theory development.
  1228 
  1229 * Code generator is now invoked via code_module (incremental code
  1230 generation) and code_library (modular code generation, ML structures
  1231 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1232 must be quoted when used as identifiers.
  1233 
  1234 * New 'value' command for reading, evaluating and printing terms using
  1235 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1236 quoted when used as identifier.
  1237 
  1238 
  1239 *** Locales ***
  1240 
  1241 * New commands for the interpretation of locale expressions in
  1242 theories (1), locales (2) and proof contexts (3).  These generate
  1243 proof obligations from the expression specification.  After the
  1244 obligations have been discharged, theorems of the expression are added
  1245 to the theory, target locale or proof context.  The synopsis of the
  1246 commands is a follows:
  1247 
  1248   (1) interpretation expr inst
  1249   (2) interpretation target < expr
  1250   (3) interpret expr inst
  1251 
  1252 Interpretation in theories and proof contexts require a parameter
  1253 instantiation of terms from the current context.  This is applied to
  1254 specifications and theorems of the interpreted expression.
  1255 Interpretation in locales only permits parameter renaming through the
  1256 locale expression.  Interpretation is smart in that interpretations
  1257 that are active already do not occur in proof obligations, neither are
  1258 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1259 inspect active interpretations of a particular locale.  For details,
  1260 see the Isar Reference manual.  Examples can be found in
  1261 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1262 
  1263 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1264 'interpret' instead.
  1265 
  1266 * New context element 'constrains' for adding type constraints to
  1267 parameters.
  1268 
  1269 * Context expressions: renaming of parameters with syntax
  1270 redeclaration.
  1271 
  1272 * Locale declaration: 'includes' disallowed.
  1273 
  1274 * Proper static binding of attribute syntax -- i.e. types / terms /
  1275 facts mentioned as arguments are always those of the locale definition
  1276 context, independently of the context of later invocations.  Moreover,
  1277 locale operations (renaming and type / term instantiation) are applied
  1278 to attribute arguments as expected.
  1279 
  1280 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1281 actual attributes; rare situations may require Attrib.attribute to
  1282 embed those attributes into Attrib.src that lack concrete syntax.
  1283 Attribute implementations need to cooperate properly with the static
  1284 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1285 Attrib.XXX_thm etc. already do the right thing without further
  1286 intervention.  Only unusual applications -- such as "where" or "of"
  1287 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1288 on the context and the facts involved -- may have to assign parsed
  1289 values to argument tokens explicitly.
  1290 
  1291 * Changed parameter management in theorem generation for long goal
  1292 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1293 theorem statement in rare situations.
  1294 
  1295 * Locale inspection command 'print_locale' omits notes elements.  Use
  1296 'print_locale!' to have them included in the output.
  1297 
  1298 
  1299 *** Provers ***
  1300 
  1301 * Provers/hypsubst.ML: improved version of the subst method, for
  1302 single-step rewriting: it now works in bound variable contexts. New is
  1303 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1304 rewrite a different subterm than the original subst method, which is
  1305 still available as 'simplesubst'.
  1306 
  1307 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1308 and quasi orders.
  1309 
  1310 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1311 reflexive-transitive closure of relations.
  1312 
  1313 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1314 limit (previously hard-coded with a value of 20) user-definable.
  1315 
  1316 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1317 is peformed already.  Object-logics merely need to finish their
  1318 initial simpset configuration as before.  INCOMPATIBILITY.
  1319 
  1320 
  1321 *** HOL ***
  1322 
  1323 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1324 
  1325   syntax (epsilon)
  1326     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1327 
  1328 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1329 and x-symbol; use option '-m epsilon' to get it actually printed.
  1330 Moreover, the mathematically important symbolic identifier \<epsilon>
  1331 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1332 
  1333 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1334 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1335 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1336 support corresponding Isar calculations.
  1337 
  1338 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1339 instead of ":".
  1340 
  1341 * theory SetInterval: changed the syntax for open intervals:
  1342 
  1343   Old       New
  1344   {..n(}    {..<n}
  1345   {)n..}    {n<..}
  1346   {m..n(}   {m..<n}
  1347   {)m..n}   {m<..n}
  1348   {)m..n(}  {m<..<n}
  1349 
  1350 The old syntax is still supported but will disappear in the next
  1351 release.  For conversion use the following Emacs search and replace
  1352 patterns (these are not perfect but work quite well):
  1353 
  1354   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1355   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1356 
  1357 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1358 equalities in commutative rings; method 'algebra' provides a generic
  1359 interface.
  1360 
  1361 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1362 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1363 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1364 be a tuple pattern.
  1365 
  1366 Some new syntax forms are available:
  1367 
  1368   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1369   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1370   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1371   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1372 
  1373 The latter form "\<Sum>x < k. e" used to be based on a separate
  1374 function "Summation", which has been discontinued.
  1375 
  1376 * theory Finite_Set: in structured induction proofs, the insert case
  1377 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1378 (insert F x)'.
  1379 
  1380 * The 'refute' command has been extended to support a much larger
  1381 fragment of HOL, including axiomatic type classes, constdefs and
  1382 typedefs, inductive datatypes and recursion.
  1383 
  1384 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1385 Requires zChaff with proof generation to be installed.  See
  1386 HOL/ex/SAT_Examples.thy for examples.
  1387 
  1388 * Datatype induction via method 'induct' now preserves the name of the
  1389 induction variable. For example, when proving P(xs::'a list) by
  1390 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1391 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1392 in unstructured proof scripts.
  1393 
  1394 * Reworked implementation of records.  Improved scalability for
  1395 records with many fields, avoiding performance problems for type
  1396 inference. Records are no longer composed of nested field types, but
  1397 of nested extension types. Therefore the record type only grows linear
  1398 in the number of extensions and not in the number of fields.  The
  1399 top-level (users) view on records is preserved.  Potential
  1400 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1401 old record representation. The type generated for a record is called
  1402 <record_name>_ext_type.
  1403 
  1404 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1405 proofs triggered by a record definition or a simproc (if
  1406 quick_and_dirty is enabled).  Definitions of large records can take
  1407 quite long.
  1408 
  1409 New simproc record_upd_simproc for simplification of multiple record
  1410 updates enabled by default.  Moreover, trivial updates are also
  1411 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1412 occasionally, since simplification is more powerful by default.
  1413 
  1414 * typedef: proper support for polymorphic sets, which contain extra
  1415 type-variables in the term.
  1416 
  1417 * Simplifier: automatically reasons about transitivity chains
  1418 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1419 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1420 old proofs break occasionally as simplification may now solve more
  1421 goals than previously.
  1422 
  1423 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1424 present.  Works for all partial orders (class "order"), in particular
  1425 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1426 just like y <= x.
  1427 
  1428 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1429 bound variable or a constant then the let is unfolded.  Otherwise
  1430 first a is simplified to b, and then f b is simplified to g. If
  1431 possible we abstract b from g arriving at "let x = b in h x",
  1432 otherwise we unfold the let and arrive at g.  The simproc can be
  1433 enabled/disabled by the reference use_let_simproc.  Potential
  1434 INCOMPATIBILITY since simplification is more powerful by default.
  1435 
  1436 * Classical reasoning: the meson method now accepts theorems as arguments.
  1437 
  1438 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1439 jobs to provide advice on the provability of subgoals.
  1440 
  1441 * Theory OrderedGroup and Ring_and_Field: various additions and
  1442 improvements to faciliate calculations involving equalities and
  1443 inequalities.
  1444 
  1445 The following theorems have been eliminated or modified
  1446 (INCOMPATIBILITY):
  1447 
  1448   abs_eq             now named abs_of_nonneg
  1449   abs_of_ge_0        now named abs_of_nonneg
  1450   abs_minus_eq       now named abs_of_nonpos
  1451   imp_abs_id         now named abs_of_nonneg
  1452   imp_abs_neg_id     now named abs_of_nonpos
  1453   mult_pos           now named mult_pos_pos
  1454   mult_pos_le        now named mult_nonneg_nonneg
  1455   mult_pos_neg_le    now named mult_nonneg_nonpos
  1456   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1457   mult_neg           now named mult_neg_neg
  1458   mult_neg_le        now named mult_nonpos_nonpos
  1459 
  1460 * Theory Parity: added rules for simplifying exponents.
  1461 
  1462 * Theory List:
  1463 
  1464 The following theorems have been eliminated or modified
  1465 (INCOMPATIBILITY):
  1466 
  1467   list_all_Nil       now named list_all.simps(1)
  1468   list_all_Cons      now named list_all.simps(2)
  1469   list_all_conv      now named list_all_iff
  1470   set_mem_eq         now named mem_iff
  1471 
  1472 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1473 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1474 
  1475 
  1476 *** HOL-Complex ***
  1477 
  1478 * Theory RealDef: better support for embedding natural numbers and
  1479 integers in the reals.
  1480 
  1481 The following theorems have been eliminated or modified
  1482 (INCOMPATIBILITY):
  1483 
  1484   exp_ge_add_one_self  now requires no hypotheses
  1485   real_of_int_add      reversed direction of equality (use [symmetric])
  1486   real_of_int_minus    reversed direction of equality (use [symmetric])
  1487   real_of_int_diff     reversed direction of equality (use [symmetric])
  1488   real_of_int_mult     reversed direction of equality (use [symmetric])
  1489 
  1490 * Theory RComplete: expanded support for floor and ceiling functions.
  1491 
  1492 * Theory Ln is new, with properties of the natural logarithm
  1493 
  1494 * Hyperreal: There is a new type constructor "star" for making
  1495 nonstandard types.  The old type names are now type synonyms:
  1496 
  1497   hypreal = real star
  1498   hypnat = nat star
  1499   hcomplex = complex star
  1500 
  1501 * Hyperreal: Many groups of similarly-defined constants have been
  1502 replaced by polymorphic versions (INCOMPATIBILITY):
  1503 
  1504   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1505 
  1506   starset      <-- starsetNat, starsetC
  1507   *s*          <-- *sNat*, *sc*
  1508   starset_n    <-- starsetNat_n, starsetC_n
  1509   *sn*         <-- *sNatn*, *scn*
  1510   InternalSets <-- InternalNatSets, InternalCSets
  1511 
  1512   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1513   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1514   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1515   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1516   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1517 
  1518 * Hyperreal: Many type-specific theorems have been removed in favor of
  1519 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1520 
  1521   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1522   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1523   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1524   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1525   right_minus <-- hypreal_add_minus
  1526   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1527   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1528   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1529   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1530   mult_1_right <-- hcomplex_mult_one_right
  1531   mult_zero_left <-- hcomplex_mult_zero_left
  1532   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1533   right_distrib <-- hypnat_add_mult_distrib2
  1534   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1535   right_inverse <-- hypreal_mult_inverse
  1536   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1537   order_refl <-- {hypreal,hypnat}_le_refl
  1538   order_trans <-- {hypreal,hypnat}_le_trans
  1539   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1540   order_less_le <-- {hypreal,hypnat}_less_le
  1541   linorder_linear <-- {hypreal,hypnat}_le_linear
  1542   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1543   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1544   add_nonneg_nonneg <-- hypreal_le_add_order
  1545 
  1546 * Hyperreal: Separate theorems having to do with type-specific
  1547 versions of constants have been merged into theorems that apply to the
  1548 new polymorphic constants (INCOMPATIBILITY):
  1549 
  1550   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1551   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1552   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1553   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1554   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1555   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1556   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1557   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1558   STAR_diff <-- {STAR,STARC}_diff
  1559   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1560     STARC_hcomplex_of_complex}_image_subset
  1561   starset_n_Un <-- starset{Nat,C}_n_Un
  1562   starset_n_Int <-- starset{Nat,C}_n_Int
  1563   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1564   starset_n_diff <-- starset{Nat,C}_n_diff
  1565   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1566   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1567   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1568   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1569   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1570   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1571   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1572   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1573   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1574   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1575   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1576   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1577   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1578   starfun_diff <-- starfun{C,RC,CR}_diff
  1579   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1580   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1581   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1582   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1583   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1584   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1585   starfun_Id <-- starfunC_Id
  1586   starfun_approx <-- starfun{Nat,CR}_approx
  1587   starfun_capprox <-- starfun{C,RC}_capprox
  1588   starfun_abs <-- starfunNat_rabs
  1589   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1590   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1591   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1592   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1593   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1594   starfun_add_approx <-- starfunCR_add_approx
  1595   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1596   starfun_divide <-- starfun{C,CR,RC}_divide
  1597   starfun_n <-- starfun{Nat,C}_n
  1598   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1599   starfun_n_add <-- starfun{Nat,C}_n_add
  1600   starfun_n_add_minus <-- starfunNat_n_add_minus
  1601   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1602   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1603   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1604 
  1605   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1606   star_n_minus <-- {hypreal,hcomplex}_minus
  1607   star_n_diff <-- {hypreal,hcomplex}_diff
  1608   star_n_mult <-- {hypreal,hcomplex}_mult
  1609   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1610   star_n_le <-- {hypreal,hypnat}_le
  1611   star_n_less <-- {hypreal,hypnat}_less
  1612   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1613   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1614   star_n_abs <-- hypreal_hrabs
  1615   star_n_divide <-- hcomplex_divide
  1616 
  1617   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1618   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1619   star_of_diff <-- hypreal_of_real_diff
  1620   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1621   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1622   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1623   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1624   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1625   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1626   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1627   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1628   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1629   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1630   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1631   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1632   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1633   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1634   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1635   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1636   star_of_power <-- hypreal_of_real_power
  1637   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1638 
  1639 * Hyperreal: new method "transfer" that implements the transfer
  1640 principle of nonstandard analysis. With a subgoal that mentions
  1641 nonstandard types like "'a star", the command "apply transfer"
  1642 replaces it with an equivalent one that mentions only standard types.
  1643 To be successful, all free variables must have standard types; non-
  1644 standard variables must have explicit universal quantifiers.
  1645 
  1646 * Hyperreal: A theory of Taylor series.
  1647 
  1648 
  1649 *** HOLCF ***
  1650 
  1651 * Discontinued special version of 'constdefs' (which used to support
  1652 continuous functions) in favor of the general Pure one with full
  1653 type-inference.
  1654 
  1655 * New simplification procedure for solving continuity conditions; it
  1656 is much faster on terms with many nested lambda abstractions (cubic
  1657 instead of exponential time).
  1658 
  1659 * New syntax for domain package: selector names are now optional.
  1660 Parentheses should be omitted unless argument is lazy, for example:
  1661 
  1662   domain 'a stream = cons "'a" (lazy "'a stream")
  1663 
  1664 * New command 'fixrec' for defining recursive functions with pattern
  1665 matching; defining multiple functions with mutual recursion is also
  1666 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1667 sinr, or any data constructor defined by the domain package. The given
  1668 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1669 syntax and examples.
  1670 
  1671 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1672 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1673 but the proof obligation additionally includes an admissibility
  1674 requirement. The packages generate instances of class cpo or pcpo,
  1675 with continuity and strictness theorems for Rep and Abs.
  1676 
  1677 * HOLCF: Many theorems have been renamed according to a more standard naming
  1678 scheme (INCOMPATIBILITY):
  1679 
  1680   foo_inject:  "foo$x = foo$y ==> x = y"
  1681   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1682   foo_less:    "(foo$x << foo$y) = (x << y)"
  1683   foo_strict:  "foo$UU = UU"
  1684   foo_defined: "... ==> foo$x ~= UU"
  1685   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1686 
  1687 
  1688 *** ZF ***
  1689 
  1690 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1691 including the First Isomorphism Theorem (on quotienting by the kernel
  1692 of a homomorphism).
  1693 
  1694 * ZF/Simplifier: install second copy of type solver that actually
  1695 makes use of TC rules declared to Isar proof contexts (or locales);
  1696 the old version is still required for ML proof scripts.
  1697 
  1698 
  1699 *** Cube ***
  1700 
  1701 * Converted to Isar theory format; use locales instead of axiomatic
  1702 theories.
  1703 
  1704 
  1705 *** ML ***
  1706 
  1707 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1708 for ||>, ||>>, |>>,
  1709 
  1710 * Pure/library.ML no longer defines its own option datatype, but uses
  1711 that of the SML basis, which has constructors NONE and SOME instead of
  1712 None and Some, as well as exception Option.Option instead of OPTION.
  1713 The functions the, if_none, is_some, is_none have been adapted
  1714 accordingly, while Option.map replaces apsome.
  1715 
  1716 * Pure/library.ML: the exception LIST has been given up in favour of
  1717 the standard exceptions Empty and Subscript, as well as
  1718 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1719 superceded by the standard hd and tl functions etc.
  1720 
  1721 A number of basic list functions are no longer exported to the ML
  1722 toplevel, as they are variants of predefined functions.  The following
  1723 suggests how one can translate existing code:
  1724 
  1725     rev_append xs ys = List.revAppend (xs, ys)
  1726     nth_elem (i, xs) = List.nth (xs, i)
  1727     last_elem xs = List.last xs
  1728     flat xss = List.concat xss
  1729     seq fs = List.app fs
  1730     partition P xs = List.partition P xs
  1731     mapfilter f xs = List.mapPartial f xs
  1732 
  1733 * Pure/library.ML: several combinators for linear functional
  1734 transformations, notably reverse application and composition:
  1735 
  1736   x |> f                f #> g
  1737   (x, y) |-> f          f #-> g
  1738 
  1739 * Pure/library.ML: introduced/changed precedence of infix operators:
  1740 
  1741   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1742   infix 2 ?;
  1743   infix 3 o oo ooo oooo;
  1744   infix 4 ~~ upto downto;
  1745 
  1746 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1747 infix operators.
  1748 
  1749 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1750 fold_map support linear functional transformations and nesting.  For
  1751 example:
  1752 
  1753   fold f [x1, ..., xN] y =
  1754     y |> f x1 |> ... |> f xN
  1755 
  1756   (fold o fold) f [xs1, ..., xsN] y =
  1757     y |> fold f xs1 |> ... |> fold f xsN
  1758 
  1759   fold f [x1, ..., xN] =
  1760     f x1 #> ... #> f xN
  1761 
  1762   (fold o fold) f [xs1, ..., xsN] =
  1763     fold f xs1 #> ... #> fold f xsN
  1764 
  1765 * Pure/library.ML: the following selectors on type 'a option are
  1766 available:
  1767 
  1768   the:               'a option -> 'a  (*partial*)
  1769   these:             'a option -> 'a  where 'a = 'b list
  1770   the_default: 'a -> 'a option -> 'a
  1771   the_list:          'a option -> 'a list
  1772 
  1773 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1774 basic operations for association lists, following natural argument
  1775 order; moreover the explicit equality predicate passed here avoids
  1776 potentially expensive polymorphic runtime equality checks.
  1777 The old functions may be expressed as follows:
  1778 
  1779   assoc = uncurry (AList.lookup (op =))
  1780   assocs = these oo AList.lookup (op =)
  1781   overwrite = uncurry (AList.update (op =)) o swap
  1782 
  1783 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1784 
  1785   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1786   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1787 
  1788 replacing make_keylist and keyfilter (occassionally used)
  1789 Naive rewrites:
  1790 
  1791   make_keylist = AList.make
  1792   keyfilter = AList.find (op =)
  1793 
  1794 * eq_fst and eq_snd now take explicit equality parameter, thus
  1795   avoiding eqtypes. Naive rewrites:
  1796 
  1797     eq_fst = eq_fst (op =)
  1798     eq_snd = eq_snd (op =)
  1799 
  1800 * Removed deprecated apl and apr (rarely used).
  1801   Naive rewrites:
  1802 
  1803     apl (n, op) =>>= curry op n
  1804     apr (op, m) =>>= fn n => op (n, m)
  1805 
  1806 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1807 provides a reasonably efficient light-weight implementation of sets as
  1808 lists.
  1809 
  1810 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1811 few new operations; existing lookup and update are now curried to
  1812 follow natural argument order (for use with fold etc.);
  1813 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1814 
  1815 * Pure/General: output via the Isabelle channels of
  1816 writeln/warning/error etc. is now passed through Output.output, with a
  1817 hook for arbitrary transformations depending on the print_mode
  1818 (cf. Output.add_mode -- the first active mode that provides a output
  1819 function wins).  Already formatted output may be embedded into further
  1820 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1821 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1822 accommodate easy composition of diagnostic messages etc.  Programmers
  1823 rarely need to care about Output.output or Output.raw at all, with
  1824 some notable exceptions: Output.output is required when bypassing the
  1825 standard channels (writeln etc.), or in token translations to produce
  1826 properly formatted results; Output.raw is required when capturing
  1827 already output material that will eventually be presented to the user
  1828 a second time.  For the default print mode, both Output.output and
  1829 Output.raw have no effect.
  1830 
  1831 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1832 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1833 cumulative results are displayed at the end of a batch session.
  1834 
  1835 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1836 replaced by File.platform_path and File.shell_path (with appropriate
  1837 hooks).  This provides a clean interface for unusual systems where the
  1838 internal and external process view of file names are different.
  1839 
  1840 * Pure: more efficient orders for basic syntactic entities: added
  1841 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1842 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1843 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1844 orders now -- potential INCOMPATIBILITY for code that depends on a
  1845 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1846 Library.sort_strings on result).
  1847 
  1848 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1849 fold_types traverse types/terms from left to right, observing natural
  1850 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1851 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1852 
  1853 * Pure: name spaces have been refined, with significant changes of the
  1854 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1855 to extern(_table).  The plain name entry path is superceded by a
  1856 general 'naming' context, which also includes the 'policy' to produce
  1857 a fully qualified name and external accesses of a fully qualified
  1858 name; NameSpace.extend is superceded by context dependent
  1859 Sign.declare_name.  Several theory and proof context operations modify
  1860 the naming context.  Especially note Theory.restore_naming and
  1861 ProofContext.restore_naming to get back to a sane state; note that
  1862 Theory.add_path is no longer sufficient to recover from
  1863 Theory.absolute_path in particular.
  1864 
  1865 * Pure: new flags short_names (default false) and unique_names
  1866 (default true) for controlling output of qualified names.  If
  1867 short_names is set, names are printed unqualified.  If unique_names is
  1868 reset, the name prefix is reduced to the minimum required to achieve
  1869 the original result when interning again, even if there is an overlap
  1870 with earlier declarations.
  1871 
  1872 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1873 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1874 (useful for printing error messages).  INCOMPATIBILITY.
  1875 
  1876 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1877 Theory.theory are now identified, referring to the universal
  1878 Context.theory (see Pure/context.ML).  Actual signature and theory
  1879 content is managed as theory data.  The old code and interfaces were
  1880 spread over many files and structures; the new arrangement introduces
  1881 considerable INCOMPATIBILITY to gain more clarity:
  1882 
  1883   Context -- theory management operations (name, identity, inclusion,
  1884     parents, ancestors, merge, etc.), plus generic theory data;
  1885 
  1886   Sign -- logical signature and syntax operations (declaring consts,
  1887     types, etc.), plus certify/read for common entities;
  1888 
  1889   Theory -- logical theory operations (stating axioms, definitions,
  1890     oracles), plus a copy of logical signature operations (consts,
  1891     types, etc.); also a few basic management operations (Theory.copy,
  1892     Theory.merge, etc.)
  1893 
  1894 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1895 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1896 for convenience -- they merely return the theory.
  1897 
  1898 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1899 
  1900 * Pure: the Isar proof context type is already defined early in Pure
  1901 as Context.proof (note that ProofContext.context and Proof.context are
  1902 aliases, where the latter is the preferred name).  This enables other
  1903 Isabelle components to refer to that type even before Isar is present.
  1904 
  1905 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1906 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1907 any of these kinds.  For example, Sign.intern typeK is now
  1908 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1909 Theory.hide_types.  Also note that former
  1910 Theory.hide_classes/types/consts are now
  1911 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1912 internalize their arguments!  INCOMPATIBILITY.
  1913 
  1914 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1915 datatype thmref (with constructors Name and NameSelection) instead of
  1916 plain string -- INCOMPATIBILITY;
  1917 
  1918 * Pure: cases produced by proof methods specify options, where NONE
  1919 means to remove case bindings -- INCOMPATIBILITY in
  1920 (RAW_)METHOD_CASES.
  1921 
  1922 * Pure: the following operations retrieve axioms or theorems from a
  1923 theory node or theory hierarchy, respectively:
  1924 
  1925   Theory.axioms_of: theory -> (string * term) list
  1926   Theory.all_axioms_of: theory -> (string * term) list
  1927   PureThy.thms_of: theory -> (string * thm) list
  1928   PureThy.all_thms_of: theory -> (string * thm) list
  1929 
  1930 * Pure: print_tac now outputs the goal through the trace channel.
  1931 
  1932 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1933 Reference Toplevel.debug (default false) controls detailed printing
  1934 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1935 controls execution profiling -- set to 1 for time and 2 for space
  1936 (both increase the runtime).
  1937 
  1938 * Isar session: The initial use of ROOT.ML is now always timed,
  1939 i.e. the log will show the actual process times, in contrast to the
  1940 elapsed wall-clock time that the outer shell wrapper produces.
  1941 
  1942 * Simplifier: improved handling of bound variables (nameless
  1943 representation, avoid allocating new strings).  Simprocs that invoke
  1944 the Simplifier recursively should use Simplifier.inherit_bounds to
  1945 avoid local name clashes.  Failure to do so produces warnings
  1946 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1947 for further details.
  1948 
  1949 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1950 bindings for all theorems stored within a given theory; this may help
  1951 in porting non-Isar theories to Isar ones, while keeping ML proof
  1952 scripts for the time being.
  1953 
  1954 * ML operator HTML.with_charset specifies the charset begin used for
  1955 generated HTML files.  For example:
  1956 
  1957   HTML.with_charset "utf-8" use_thy "Hebrew";
  1958   HTML.with_charset "utf-8" use_thy "Chinese";
  1959 
  1960 
  1961 *** System ***
  1962 
  1963 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1964 isabelle, isatool etc.).
  1965 
  1966 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1967 isatool doc, isatool mkdir, display_drafts etc.).
  1968 
  1969 * isatool usedir: option -f allows specification of the ML file to be
  1970 used by Isabelle; default is ROOT.ML.
  1971 
  1972 * New isatool version outputs the version identifier of the Isabelle
  1973 distribution being used.
  1974 
  1975 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1976 (containing Boolean satisfiability problems) into Isabelle/HOL
  1977 theories.
  1978 
  1979 
  1980 
  1981 New in Isabelle2004 (April 2004)
  1982 --------------------------------
  1983 
  1984 *** General ***
  1985 
  1986 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1987   Replaces linorder.ML.
  1988 
  1989 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1990   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1991   (\<a>...\<z>), are now considered normal letters, and can therefore
  1992   be used anywhere where an ASCII letter (a...zA...Z) has until
  1993   now. COMPATIBILITY: This obviously changes the parsing of some
  1994   terms, especially where a symbol has been used as a binder, say
  1995   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1996   as an identifier.  Fix it by inserting a space around former
  1997   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1998   existing theory and ML files.
  1999 
  2000 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2001 
  2002 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2003   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2004   a normal (but invisible) letter. For multiple letter subscripts repeat
  2005   \<^isub> like this: x\<^isub>1\<^isub>2.
  2006 
  2007 * Pure: There are now sub-/superscripts that can span more than one
  2008   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2009   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2010   superscript. The new control characters are not identifier parts.
  2011 
  2012 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2013   content of "..." to the latex file instead of \isacntrl... . The "..."
  2014   may consist of any printable characters excluding the end bracket >.
  2015 
  2016 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2017   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2018   declare constants "final", which prevents their being given a definition
  2019   later.  It is useful for constants whose behaviour is fixed axiomatically
  2020   rather than definitionally, such as the meta-logic connectives.
  2021 
  2022 * Pure: 'instance' now handles general arities with general sorts
  2023   (i.e. intersections of classes),
  2024 
  2025 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2026   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2027   It can be changed to alter the colors/layout of generated pages.
  2028 
  2029 
  2030 *** Isar ***
  2031 
  2032 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2033   cut_tac, subgoal_tac and thin_tac:
  2034   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2035     locales are no longer forced to write Isar proof scripts.
  2036     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2037     emulations.
  2038   - INCOMPATIBILITY: names of variables to be instantiated may no
  2039     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2040     This is consistent with the instantiation attribute "where".
  2041 
  2042 * Attributes "where" and "of":
  2043   - Now take type variables of instantiated theorem into account when reading
  2044     the instantiation string.  This fixes a bug that caused instantiated
  2045     theorems to have too special types in some circumstances.
  2046   - "where" permits explicit instantiations of type variables.
  2047 
  2048 * Calculation commands "moreover" and "also" no longer interfere with
  2049   current facts ("this"), admitting arbitrary combinations with "then"
  2050   and derived forms.
  2051 
  2052 * Locales:
  2053   - Goal statements involving the context element "includes" no longer
  2054     generate theorems with internal delta predicates (those ending on
  2055     "_axioms") in the premise.
  2056     Resolve particular premise with <locale>.intro to obtain old form.
  2057   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2058     specification and "includes" elements in goal statement.
  2059   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2060     [intro?] and [elim?] (respectively) by default.
  2061   - Experimental command for instantiation of locales in proof contexts:
  2062         instantiate <label>[<attrs>]: <loc>
  2063     Instantiates locale <loc> and adds all its theorems to the current context
  2064     taking into account their attributes.  Label and attrs are optional
  2065     modifiers, like in theorem declarations.  If present, names of
  2066     instantiated theorems are qualified with <label>, and the attributes
  2067     <attrs> are applied after any attributes these theorems might have already.
  2068       If the locale has assumptions, a chained fact of the form
  2069     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2070     are derived.  The command does not support old-style locales declared
  2071     with "locale (open)".
  2072       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2073 
  2074 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2075   (Isar) contexts.
  2076 
  2077 
  2078 *** HOL ***
  2079 
  2080 * Proof import: new image HOL4 contains the imported library from
  2081   the HOL4 system with about 2500 theorems. It is imported by
  2082   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2083   can be used like any other Isabelle image.  See
  2084   HOL/Import/HOL/README for more information.
  2085 
  2086 * Simplifier:
  2087   - Much improved handling of linear and partial orders.
  2088     Reasoners for linear and partial orders are set up for type classes
  2089     "linorder" and "order" respectively, and are added to the default simpset
  2090     as solvers.  This means that the simplifier can build transitivity chains
  2091     to solve goals from the assumptions.
  2092   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2093     of blast or auto after simplification become unnecessary because the goal
  2094     is solved by simplification already.
  2095 
  2096 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2097     all proved in axiomatic type classes for semirings, rings and fields.
  2098 
  2099 * Numerics:
  2100   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2101     now formalized using the Ring_and_Field theory mentioned above.
  2102   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2103     than before, because now they are set up once in a generic manner.
  2104   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2105     Look for the general versions in Ring_and_Field (and Power if they concern
  2106     exponentiation).
  2107 
  2108 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2109 
  2110 * Records:
  2111   - Record types are now by default printed with their type abbreviation
  2112     instead of the list of all field types. This can be configured via
  2113     the reference "print_record_type_abbr".
  2114   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2115     (not enabled by default).
  2116   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2117     EX x. x = sel r to True (not enabled by default).
  2118   - Tactic "record_split_simp_tac" to split and simplify records added.
  2119 
  2120 * 'specification' command added, allowing for definition by
  2121   specification.  There is also an 'ax_specification' command that
  2122   introduces the new constants axiomatically.
  2123 
  2124 * arith(_tac) is now able to generate counterexamples for reals as well.
  2125 
  2126 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2127 
  2128 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2129   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2130 
  2131 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2132   matrix theory to linear programming.
  2133 
  2134 * Unions and Intersections:
  2135   The latex output syntax of UN and INT has been changed
  2136   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2137   i.e. the index formulae has become a subscript.
  2138   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2139 
  2140 * Unions and Intersections over Intervals:
  2141   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2142   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2143   like in normal math, and corresponding versions for < and for intersection.
  2144 
  2145 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2146   lexicographic dictonary ordering has been added as "lexord".
  2147 
  2148 * ML: the legacy theory structures Int and List have been removed. They had
  2149   conflicted with ML Basis Library structures having the same names.
  2150 
  2151 * 'refute' command added to search for (finite) countermodels.  Only works
  2152   for a fragment of HOL.  The installation of an external SAT solver is
  2153   highly recommended.  See "HOL/Refute.thy" for details.
  2154 
  2155 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2156   formulae under an assignment of free variables to random values.
  2157   In contrast to 'refute', it can deal with inductive datatypes,
  2158   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2159   for examples.
  2160 
  2161 
  2162 *** HOLCF ***
  2163 
  2164 * Streams now come with concatenation and are part of the HOLCF image
  2165 
  2166 
  2167 
  2168 New in Isabelle2003 (May 2003)
  2169 ------------------------------
  2170 
  2171 *** General ***
  2172 
  2173 * Provers/simplifier:
  2174 
  2175   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2176     Assumptions are now subject to complete mutual simplification,
  2177     not just from left to right. The simplifier now preserves
  2178     the order of assumptions.
  2179 
  2180     Potential INCOMPATIBILITY:
  2181 
  2182     -- simp sometimes diverges where the old version did
  2183        not, e.g. invoking simp on the goal
  2184 
  2185         [| P (f x); y = x; f x = f y |] ==> Q
  2186 
  2187        now gives rise to the infinite reduction sequence
  2188 
  2189         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2190 
  2191        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2192        kind of problem.
  2193 
  2194     -- Tactics combining classical reasoner and simplification (such as auto)
  2195        are also affected by this change, because many of them rely on
  2196        simp. They may sometimes diverge as well or yield a different numbers
  2197        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2198        in case of problems. Sometimes subsequent calls to the classical
  2199        reasoner will fail because a preceeding call to the simplifier too
  2200        eagerly simplified the goal, e.g. deleted redundant premises.
  2201 
  2202   - The simplifier trace now shows the names of the applied rewrite rules
  2203 
  2204   - You can limit the number of recursive invocations of the simplifier
  2205     during conditional rewriting (where the simplifie tries to solve the
  2206     conditions before applying the rewrite rule):
  2207     ML "simp_depth_limit := n"
  2208     where n is an integer. Thus you can force termination where previously
  2209     the simplifier would diverge.
  2210 
  2211   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2212 
  2213   - No longer aborts on failed congruence proof.  Instead, the
  2214     congruence is ignored.
  2215 
  2216 * Pure: New generic framework for extracting programs from constructive
  2217   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2218   as HOL/Extraction for some case studies.
  2219 
  2220 * Pure: The main goal of the proof state is no longer shown by default, only
  2221 the subgoals. This behaviour is controlled by a new flag.
  2222    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2223 (ML: Proof.show_main_goal).
  2224 
  2225 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2226 rules whose conclusion matches subgoal 1:
  2227       PG menu: Isabelle/Isar -> Show me -> matching rules
  2228 The rules are ordered by how closely they match the subgoal.
  2229 In particular, rules that solve a subgoal outright are displayed first
  2230 (or rather last, the way they are printed).
  2231 (ML: ProofGeneral.print_intros())
  2232 
  2233 * Pure: New flag trace_unify_fail causes unification to print
  2234 diagnostic information (PG: in trace buffer) when it fails. This is
  2235 useful for figuring out why single step proofs like rule, erule or
  2236 assumption failed.
  2237 
  2238 * Pure: Locale specifications now produce predicate definitions
  2239 according to the body of text (covering assumptions modulo local
  2240 definitions); predicate "loc_axioms" covers newly introduced text,
  2241 while "loc" is cumulative wrt. all included locale expressions; the
  2242 latter view is presented only on export into the global theory
  2243 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2244 on the old view without predicates;
  2245 
  2246 * Pure: predefined locales "var" and "struct" are useful for sharing
  2247 parameters (as in CASL, for example); just specify something like
  2248 ``var x + var y + struct M'' as import;
  2249 
  2250 * Pure: improved thms_containing: proper indexing of facts instead of
  2251 raw theorems; check validity of results wrt. current name space;
  2252 include local facts of proof configuration (also covers active
  2253 locales), cover fixed variables in index; may use "_" in term
  2254 specification; an optional limit for the number of printed facts may
  2255 be given (the default is 40);
  2256 
  2257 * Pure: disallow duplicate fact bindings within new-style theory files
  2258 (batch-mode only);
  2259 
  2260 * Provers: improved induct method: assumptions introduced by case
  2261 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2262 the goal statement); "foo" still refers to all facts collectively;
  2263 
  2264 * Provers: the function blast.overloaded has been removed: all constants
  2265 are regarded as potentially overloaded, which improves robustness in exchange
  2266 for slight decrease in efficiency;
  2267 
  2268 * Provers/linorder: New generic prover for transitivity reasoning over
  2269 linear orders.  Note: this prover is not efficient!
  2270 
  2271 * Isar: preview of problems to finish 'show' now produce an error
  2272 rather than just a warning (in interactive mode);
  2273 
  2274 
  2275 *** HOL ***
  2276 
  2277 * arith(_tac)
  2278 
  2279  - Produces a counter example if it cannot prove a goal.
  2280    Note that the counter example may be spurious if the goal is not a formula
  2281    of quantifier-free linear arithmetic.
  2282    In ProofGeneral the counter example appears in the trace buffer.
  2283 
  2284  - Knows about div k and mod k where k is a numeral of type nat or int.
  2285 
  2286  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2287    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2288    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2289 
  2290 * simp's arithmetic capabilities have been enhanced a bit: it now
  2291 takes ~= in premises into account (by performing a case split);
  2292 
  2293 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2294 are distributed over a sum of terms;
  2295 
  2296 * New tactic "trans_tac" and method "trans" instantiate
  2297 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2298 "<=", "<" and "=").
  2299 
  2300 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2301 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2302 
  2303 * 'typedef' command has new option "open" to suppress the set
  2304 definition;
  2305 
  2306 * functions Min and Max on finite sets have been introduced (theory
  2307 Finite_Set);
  2308 
  2309 * attribute [symmetric] now works for relations as well; it turns
  2310 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2311 
  2312 * induct over a !!-quantified statement (say !!x1..xn):
  2313   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2314 
  2315 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2316 %x. None. Warning: empty_def now refers to the previously hidden definition
  2317 of the empty set.
  2318 
  2319 * Algebra: formalization of classical algebra.  Intended as base for
  2320 any algebraic development in Isabelle.  Currently covers group theory
  2321 (up to Sylow's theorem) and ring theory (Universal Property of
  2322 Univariate Polynomials).  Contributions welcome;
  2323 
  2324 * GroupTheory: deleted, since its material has been moved to Algebra;
  2325 
  2326 * Complex: new directory of the complex numbers with numeric constants,
  2327 nonstandard complex numbers, and some complex analysis, standard and
  2328 nonstandard (Jacques Fleuriot);
  2329 
  2330 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2331 
  2332 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2333 Fleuriot);
  2334 
  2335 * Real/HahnBanach: updated and adapted to locales;
  2336 
  2337 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2338 Gray and Kramer);
  2339 
  2340 * UNITY: added the Meier-Sanders theory of progress sets;
  2341 
  2342 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2343 as abstract algorithms, instantiated to the JVM;
  2344 
  2345 * Bali: Java source language formalization. Type system, operational
  2346 semantics, axiomatic semantics. Supported language features:
  2347 classes, interfaces, objects,virtual methods, static methods,
  2348 static/instance fields, arrays, access modifiers, definite
  2349 assignment, exceptions.
  2350 
  2351 
  2352 *** ZF ***
  2353 
  2354 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2355 universe, etc.);
  2356 
  2357 * Main ZF: virtually all theories converted to new-style format;
  2358 
  2359 
  2360 *** ML ***
  2361 
  2362 * Pure: Tactic.prove provides sane interface for internal proofs;
  2363 omits the infamous "standard" operation, so this is more appropriate
  2364 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2365 
  2366 * Pure: improved error reporting of simprocs;
  2367 
  2368 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2369 up simprocs;
  2370 
  2371 
  2372 *** Document preparation ***
  2373 
  2374 * uses \par instead of \\ for line breaks in theory text. This may
  2375 shift some page breaks in large documents. To get the old behaviour
  2376 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2377 
  2378 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2379 other packages
  2380 
  2381 * \<euro> now needs package babel/greek instead of marvosym (which
  2382 broke \Rightarrow)
  2383 
  2384 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2385 textcomp package)
  2386 
  2387 
  2388 
  2389 New in Isabelle2002 (March 2002)
  2390 --------------------------------
  2391 
  2392 *** Document preparation ***
  2393 
  2394 * greatly simplified document preparation setup, including more
  2395 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2396 instructive isatool mkdir; users should basically be able to get
  2397 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2398 users may run a separate document processing stage manually like this:
  2399 "isatool usedir -D output HOL Test && isatool document Test/output";
  2400 
  2401 * theory dependency graph may now be incorporated into documents;
  2402 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2403 with \includegraphics of LaTeX;
  2404 
  2405 * proper spacing of consecutive markup elements, especially text
  2406 blocks after section headings;
  2407 
  2408 * support bold style (for single symbols only), input syntax is like
  2409 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2410 
  2411 * \<bullet> is now output as bold \cdot by default, which looks much
  2412 better in printed text;
  2413 
  2414 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2415 note that these symbols are currently unavailable in Proof General /
  2416 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2417 
  2418 * isatool latex no longer depends on changed TEXINPUTS, instead
  2419 isatool document copies the Isabelle style files to the target
  2420 location;
  2421 
  2422 
  2423 *** Isar ***
  2424 
  2425 * Pure/Provers: improved proof by cases and induction;
  2426   - 'case' command admits impromptu naming of parameters (such as
  2427     "case (Suc n)");
  2428   - 'induct' method divinates rule instantiation from the inductive
  2429     claim; no longer requires excessive ?P bindings for proper
  2430     instantiation of cases;
  2431   - 'induct' method properly enumerates all possibilities of set/type
  2432     rules; as a consequence facts may be also passed through *type*
  2433     rules without further ado;
  2434   - 'induct' method now derives symbolic cases from the *rulified*
  2435     rule (before it used to rulify cases stemming from the internal
  2436     atomized version); this means that the context of a non-atomic
  2437     statement becomes is included in the hypothesis, avoiding the
  2438     slightly cumbersome show "PROP ?case" form;
  2439   - 'induct' may now use elim-style induction rules without chaining
  2440     facts, using ``missing'' premises from the goal state; this allows
  2441     rules stemming from inductive sets to be applied in unstructured
  2442     scripts, while still benefitting from proper handling of non-atomic
  2443     statements; NB: major inductive premises need to be put first, all
  2444     the rest of the goal is passed through the induction;
  2445   - 'induct' proper support for mutual induction involving non-atomic
  2446     rule statements (uses the new concept of simultaneous goals, see
  2447     below);
  2448   - append all possible rule selections, but only use the first
  2449     success (no backtracking);
  2450   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2451   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2452   - added 'print_induct_rules' (covered by help item in recent Proof
  2453     General versions);
  2454   - moved induct/cases attributes to Pure, methods to Provers;
  2455   - generic method setup instantiated for FOL and HOL;
  2456 
  2457 * Pure: support multiple simultaneous goal statements, for example
  2458 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2459 meta-level mechanism, this acts as if several individual goals had
  2460 been stated separately; in particular common proof methods need to be
  2461 repeated in order to cover all claims; note that a single elimination
  2462 step is *not* sufficient to establish the two conjunctions, so this
  2463 fails:
  2464 
  2465   assume "A & B" then have A and B ..   (*".." fails*)
  2466 
  2467 better use "obtain" in situations as above; alternative refer to
  2468 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2469 
  2470 * Pure: proper integration with ``locales''; unlike the original
  2471 version by Florian Kammller, Isar locales package high-level proof
  2472 contexts rather than raw logical ones (e.g. we admit to include
  2473 attributes everywhere); operations on locales include merge and
  2474 rename; support for implicit arguments (``structures''); simultaneous
  2475 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2476 some examples;
  2477 
  2478 * Pure: the following commands have been ``localized'', supporting a
  2479 target locale specification "(in name)": 'lemma', 'theorem',
  2480 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2481 stored both within the locale and at the theory level (exported and
  2482 qualified by the locale name);
  2483 
  2484 * Pure: theory goals may now be specified in ``long'' form, with
  2485 ad-hoc contexts consisting of arbitrary locale elements. for example
  2486 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2487 definitions may be given, too); the result is a meta-level rule with
  2488 the context elements being discharged in the obvious way;
  2489 
  2490 * Pure: new proof command 'using' allows to augment currently used
  2491 facts after a goal statement ('using' is syntactically analogous to
  2492 'apply', but acts on the goal's facts only); this allows chained facts
  2493 to be separated into parts given before and after a claim, as in
  2494 ``from a and b have C using d and e <proof>'';
  2495 
  2496 * Pure: renamed "antecedent" case to "rule_context";
  2497 
  2498 * Pure: new 'judgment' command records explicit information about the
  2499 object-logic embedding (used by several tools internally); no longer
  2500 use hard-wired "Trueprop";
  2501 
  2502 * Pure: added 'corollary' command;
  2503 
  2504 * Pure: fixed 'token_translation' command;
  2505 
  2506 * Pure: removed obsolete 'exported' attribute;
  2507 
  2508 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2509 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2510 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2511 
  2512 * Pure: method 'atomize' presents local goal premises as object-level
  2513 statements (atomic meta-level propositions); setup controlled via
  2514 rewrite rules declarations of 'atomize' attribute; example
  2515 application: 'induct' method with proper rule statements in improper
  2516 proof *scripts*;
  2517 
  2518 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2519 now consider the syntactic context of assumptions, giving a better
  2520 chance to get type-inference of the arguments right (this is
  2521 especially important for locales);
  2522 
  2523 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2524 mode;
  2525 
  2526 * Pure/obtain: the formal conclusion "thesis", being marked as
  2527 ``internal'', may no longer be reference directly in the text;
  2528 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2529 situations;
  2530 
  2531 * Pure: generic 'sym' attribute which declares a rule both as pure
  2532 'elim?' and for the 'symmetric' operation;
  2533 
  2534 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2535 text; the fixed correlation with particular command syntax has been
  2536 discontinued;
  2537 
  2538 * Pure: new method 'rules' is particularly well-suited for proof
  2539 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2540 but often produces more compact proof terms with less detours;
  2541 
  2542 * Pure/Provers/classical: simplified integration with pure rule
  2543 attributes and methods; the classical "intro?/elim?/dest?"
  2544 declarations coincide with the pure ones; the "rule" method no longer
  2545 includes classically swapped intros; "intro" and "elim" methods no
  2546 longer pick rules from the context; also got rid of ML declarations
  2547 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2548 INCOMPATIBILITY;
  2549 
  2550 * Provers/classical: attribute 'swapped' produces classical inversions
  2551 of introduction rules;
  2552 
  2553 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2554 rules instead of full simplifier context; 'iff' attribute handles
  2555 conditional rules;
  2556 
  2557 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2558 
  2559 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2560 "(permissive)" option to recover old behavior;
  2561 
  2562 * HOL: 'inductive' no longer features separate (collective) attributes
  2563 for 'intros' (was found too confusing);
  2564 
  2565 * HOL: properly declared induction rules less_induct and
  2566 wf_induct_rule;
  2567 
  2568 
  2569 *** HOL ***
  2570 
  2571 * HOL: moved over to sane numeral syntax; the new policy is as
  2572 follows:
  2573 
  2574   - 0 and 1 are polymorphic constants, which are defined on any
  2575   numeric type (nat, int, real etc.);
  2576 
  2577   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2578   binary representation internally;
  2579 
  2580   - type nat has special constructor Suc, and generally prefers Suc 0
  2581   over 1::nat and Suc (Suc 0) over 2::nat;
  2582 
  2583 This change may cause significant problems of INCOMPATIBILITY; here
  2584 are some hints on converting existing sources:
  2585 
  2586   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2587   entities, so expressions involving "-" (unary or binary minus) need
  2588   to be spaced properly;
  2589 
  2590   - existing occurrences of "1" may need to be constraint "1::nat" or
  2591   even replaced by Suc 0; similar for old "2";
  2592 
  2593   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2594 
  2595   - remove all special provisions on numerals in proofs;
  2596 
  2597 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2598 representation (depends on bin_arith_simps in the default context);
  2599 
  2600 * HOL: symbolic syntax for x^2 (numeral 2);
  2601 
  2602 * HOL: the class of all HOL types is now called "type" rather than
  2603 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2604 in axclass/classes, instance/arities, and (usually rare) occurrences
  2605 in typings (of consts etc.); internally the class is called
  2606 "HOL.type", ML programs should refer to HOLogic.typeS;
  2607 
  2608 * HOL/record package improvements:
  2609   - new derived operations "fields" to build a partial record section,
  2610     "extend" to promote a fixed record to a record scheme, and
  2611     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2612     declared as simp by default;
  2613   - shared operations ("more", "fields", etc.) now need to be always
  2614     qualified) --- potential INCOMPATIBILITY;
  2615   - removed "make_scheme" operations (use "make" with "extend") --
  2616     INCOMPATIBILITY;
  2617   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2618   - provides cases/induct rules for use with corresponding Isar
  2619     methods (for concrete records, record schemes, concrete more
  2620     parts, and schematic more parts -- in that order);
  2621   - internal definitions directly based on a light-weight abstract
  2622     theory of product types over typedef rather than datatype;
  2623 
  2624 * HOL: generic code generator for generating executable ML code from
  2625 specifications; specific support for HOL constructs such as inductive
  2626 datatypes and sets, as well as recursive functions; can be invoked
  2627 via 'generate_code' theory section;
  2628 
  2629 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2630 
  2631 * HOL: consolidated and renamed several theories.  In particular:
  2632         Ord.thy has been absorbed into HOL.thy
  2633         String.thy has been absorbed into List.thy
  2634 
  2635 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2636 (beware of argument permutation!);
  2637 
  2638 * HOL: linorder_less_split superseded by linorder_cases;
  2639 
  2640 * HOL/List: "nodups" renamed to "distinct";
  2641 
  2642 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2643 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2644   - Ex_def has changed, now need to use some_eq_ex
  2645 
  2646 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2647 in this (rare) case use:
  2648 
  2649   delSWrapper "split_all_tac"
  2650   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2651 
  2652 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2653 MAY FAIL;
  2654 
  2655 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2656 Isabelle's type classes, ^ on functions and relations has too general
  2657 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2658 necessary to attach explicit type constraints;
  2659 
  2660 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2661 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2662 renamed accordingly (eg "compI" -> "rel_compI").
  2663 
  2664 * HOL: syntax translations now work properly with numerals and records
  2665 expressions;
  2666 
  2667 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2668 of "lam" -- INCOMPATIBILITY;
  2669 
  2670 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2671 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2672 renamed "Product_Type.unit";
  2673 
  2674 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2675 
  2676 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2677 the "cases" method);
  2678 
  2679 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2680 Florian Kammller);
  2681 
  2682 * HOL/IMP: updated and converted to new-style theory format; several
  2683 parts turned into readable document, with proper Isar proof texts and
  2684 some explanations (by Gerwin Klein);
  2685 
  2686 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2687 
  2688 * HOL-Hyperreal is now a logic image;
  2689 
  2690 
  2691 *** HOLCF ***
  2692 
  2693 * Isar: consts/constdefs supports mixfix syntax for continuous
  2694 operations;
  2695 
  2696 * Isar: domain package adapted to new-style theory format, e.g. see
  2697 HOLCF/ex/Dnat.thy;
  2698 
  2699 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2700 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2701 lift.induct_tac, always use UU instead of Undef;
  2702 
  2703 * HOLCF/IMP: updated and converted to new-style theory;
  2704 
  2705 
  2706 *** ZF ***
  2707 
  2708 * Isar: proper integration of logic-specific tools and packages,
  2709 including theory commands '(co)inductive', '(co)datatype',
  2710 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2711 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2712 
  2713 * theory Main no longer includes AC; for the Axiom of Choice, base
  2714 your theory on Main_ZFC;
  2715 
  2716 * the integer library now covers quotients and remainders, with many
  2717 laws relating division to addition, multiplication, etc.;
  2718 
  2719 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2720 typeless version of the formalism;
  2721 
  2722 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2723 format;
  2724 
  2725 * ZF/Induct: new directory for examples of inductive definitions,
  2726 including theory Multiset for multiset orderings; converted to
  2727 new-style theory format;
  2728 
  2729 * ZF: many new theorems about lists, ordinals, etc.;
  2730 
  2731 
  2732 *** General ***
  2733 
  2734 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2735 variable proof controls level of detail: 0 = no proofs (only oracle
  2736 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2737 also ref manual for further ML interfaces;
  2738 
  2739 * Pure/axclass: removed obsolete ML interface
  2740 goal_subclass/goal_arity;
  2741 
  2742 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2743 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2744 separate tokens, so expressions involving minus need to be spaced
  2745 properly;
  2746 
  2747 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2748 rather than "infixl" or "infixr";
  2749 
  2750 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2751 sort constraint specifications in type inference; e.g. "x::_::foo"
  2752 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2753 type variable);
  2754 
  2755 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2756 control output of nested => (types); the default behavior is
  2757 "type_brackets";
  2758 
  2759 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2760 tokens into AST constants;
  2761 
  2762 * Pure/syntax: prefer later declarations of translations and print
  2763 translation functions; potential INCOMPATIBILITY: need to reverse
  2764 multiple declarations for same syntax element constant;
  2765 
  2766 * Pure/show_hyps reset by default (in accordance to existing Isar
  2767 practice);
  2768 
  2769 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2770 addSafter;
  2771 
  2772 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2773 as well;
  2774 
  2775 * system: tested support for MacOS X; should be able to get Isabelle +
  2776 Proof General to work in a plain Terminal after installing Poly/ML
  2777 (e.g. from the Isabelle distribution area) and GNU bash alone
  2778 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2779 support requires further installations, e.g. from
  2780 http://fink.sourceforge.net/);
  2781 
  2782 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2783 
  2784 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2785 of 40 MB), cf. ML_OPTIONS;
  2786 
  2787 * system: Proof General keywords specification is now part of the
  2788 Isabelle distribution (see etc/isar-keywords.el);
  2789 
  2790 * system: support for persistent Proof General sessions (refrain from
  2791 outdating all loaded theories on startup); user may create writable
  2792 logic images like this: ``isabelle -q HOL Test'';
  2793 
  2794 * system: smart selection of Isabelle process versus Isabelle
  2795 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2796 run both "isabelle" and "Isabelle" even if file names are badly
  2797 damaged (executable inspects the case of the first letter of its own
  2798 name); added separate "isabelle-process" and "isabelle-interface";
  2799 
  2800 * system: refrain from any attempt at filtering input streams; no
  2801 longer support ``8bit'' encoding of old isabelle font, instead proper
  2802 iso-latin characters may now be used; the related isatools
  2803 "symbolinput" and "nonascii" have disappeared as well;
  2804 
  2805 * system: removed old "xterm" interface (the print modes "xterm" and
  2806 "xterm_color" are still available for direct use in a suitable
  2807 terminal);
  2808 
  2809 
  2810 
  2811 New in Isabelle99-2 (February 2001)
  2812 -----------------------------------
  2813 
  2814 *** Overview of INCOMPATIBILITIES ***
  2815 
  2816 * HOL: please note that theories in the Library and elsewhere often use the
  2817 new-style (Isar) format; to refer to their theorems in an ML script you must
  2818 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2819 
  2820 * HOL: inductive package no longer splits induction rule aggressively,
  2821 but only as far as specified by the introductions given; the old
  2822 format may be recovered via ML function complete_split_rule or attribute
  2823 'split_rule (complete)';
  2824 
  2825 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2826 gfp_Tarski to gfp_unfold;
  2827 
  2828 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2829 
  2830 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2831 relation); infix "^^" has been renamed "``"; infix "``" has been
  2832 renamed "`"; "univalent" has been renamed "single_valued";
  2833 
  2834 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2835 operation;
  2836 
  2837 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2838 
  2839 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2840 
  2841 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2842 consequence, it is no longer monotonic wrt. the local goal context
  2843 (which is now passed through the inductive cases);
  2844 
  2845 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2846 \<gg> to \<ggreater>;
  2847 
  2848 
  2849 *** Document preparation ***
  2850 
  2851 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2852 available: are "it" for near math-mode best-style output, "sl" for
  2853 slanted text style, and "tt" for plain type-writer; if no
  2854 \isabellestyle command is given, output is according to slanted
  2855 type-writer);
  2856 
  2857 * support sub/super scripts (for single symbols only), input syntax is
  2858 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2859 
  2860 * some more standard symbols; see Appendix A of the system manual for
  2861 the complete list of symbols defined in isabellesym.sty;
  2862 
  2863 * improved isabelle style files; more abstract symbol implementation
  2864 (should now use \isamath{...} and \isatext{...} in custom symbol
  2865 definitions);
  2866 
  2867 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2868 state; Note that presentation of goal states does not conform to
  2869 actual human-readable proof documents.  Please do not include goal
  2870 states into document output unless you really know what you are doing!
  2871 
  2872 * proper indentation of antiquoted output with proportional LaTeX
  2873 fonts;
  2874 
  2875 * no_document ML operator temporarily disables LaTeX document
  2876 generation;
  2877 
  2878 * isatool unsymbolize tunes sources for plain ASCII communication;
  2879 
  2880 
  2881 *** Isar ***
  2882 
  2883 * Pure: Isar now suffers initial goal statements to contain unbound
  2884 schematic variables (this does not conform to actual readable proof
  2885 documents, due to unpredictable outcome and non-compositional proof
  2886 checking); users who know what they are doing may use schematic goals
  2887 for Prolog-style synthesis of proven results;
  2888 
  2889 * Pure: assumption method (an implicit finishing) now handles actual
  2890 rules as well;
  2891 
  2892 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2893 initial goal, declare "that" only as Pure intro (only for single
  2894 steps); the "that" rule assumption may now be involved in implicit
  2895 finishing, thus ".." becomes a feasible for trivial obtains;
  2896 
  2897 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2898 instance proofs may be performed by "..";
  2899 
  2900 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2901 statements as well;
  2902 
  2903 * Pure: more robust selection of calculational rules;
  2904 
  2905 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2906 rule (as well as the assumption rule);
  2907 
  2908 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2909 lemmas, using the graph browser tool;
  2910 
  2911 * Pure: predict failure of "show" in interactive mode;
  2912 
  2913 * Pure: 'thms_containing' now takes actual terms as arguments;
  2914 
  2915 * HOL: improved method 'induct' --- now handles non-atomic goals
  2916 (potential INCOMPATIBILITY); tuned error handling;
  2917 
  2918 * HOL: cases and induct rules now provide explicit hints about the
  2919 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2920 any remaining facts are inserted into the goal verbatim;
  2921 
  2922 * HOL: local contexts (aka cases) may now contain term bindings as
  2923 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2924 the result to be shown in each case;
  2925 
  2926 * HOL: added 'recdef_tc' command;
  2927 
  2928 * isatool convert assists in eliminating legacy ML scripts;
  2929 
  2930 
  2931 *** HOL ***
  2932 
  2933 * HOL/Library: a collection of generic theories to be used together
  2934 with main HOL; the theory loader path already includes this directory
  2935 by default; the following existing theories have been moved here:
  2936 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2937 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2938 
  2939 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2940 modelling and verification task performed in Isabelle/HOL +
  2941 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2942 
  2943 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2944 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2945 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2946 'domain', this makes the theory consistent with mathematical
  2947 literature;
  2948 
  2949 * HOL basics: added overloaded operations "inverse" and "divide"
  2950 (infix "/"), syntax for generic "abs" operation, generic summation
  2951 operator \<Sum>;
  2952 
  2953 * HOL/typedef: simplified package, provide more useful rules (see also
  2954 HOL/subset.thy);
  2955 
  2956 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2957 now expressed as a proper nested rule (old-style tactic scripts may
  2958 require atomize_strip_tac to cope with non-atomic premises);
  2959 
  2960 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2961 to "split_conv" (old name still available for compatibility);
  2962 
  2963 * HOL: improved concrete syntax for strings (e.g. allows translation
  2964 rules with string literals);
  2965 
  2966 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2967  and Fleuriot's mechanization of analysis, including the transcendental
  2968  functions for the reals;
  2969 
  2970 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2971 
  2972 
  2973 *** CTT ***
  2974 
  2975 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2976 "lam" is displayed as TWO lambda-symbols
  2977 
  2978 * CTT: theory Main now available, containing everything (that is, Bool
  2979 and Arith);
  2980 
  2981 
  2982 *** General ***
  2983 
  2984 * Pure: the Simplifier has been implemented properly as a derived rule
  2985 outside of the actual kernel (at last!); the overall performance
  2986 penalty in practical applications is about 50%, while reliability of
  2987 the Isabelle inference kernel has been greatly improved;
  2988 
  2989 * print modes "brackets" and "no_brackets" control output of nested =>
  2990 (types) and ==> (props); the default behaviour is "brackets";
  2991 
  2992 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2993 as assumptions as well;
  2994 
  2995 * system: support Poly/ML 4.0;
  2996 
  2997 * system: isatool install handles KDE version 1 or 2;
  2998 
  2999 
  3000 
  3001 New in Isabelle99-1 (October 2000)
  3002 ----------------------------------
  3003 
  3004 *** Overview of INCOMPATIBILITIES ***
  3005 
  3006 * HOL: simplification of natural numbers is much changed; to partly
  3007 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3008 issue the following ML commands:
  3009 
  3010   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3011   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3012 
  3013 * HOL: simplification no longer dives into case-expressions; this is
  3014 controlled by "t.weak_case_cong" for each datatype t;
  3015 
  3016 * HOL: nat_less_induct renamed to less_induct;
  3017 
  3018 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3019 fixsome to patch .thy and .ML sources automatically;
  3020 
  3021   select_equality  -> some_equality
  3022   select_eq_Ex     -> some_eq_ex
  3023   selectI2EX       -> someI2_ex
  3024   selectI2         -> someI2
  3025   selectI          -> someI
  3026   select1_equality -> some1_equality
  3027   Eps_sym_eq       -> some_sym_eq_trivial
  3028   Eps_eq           -> some_eq_trivial
  3029 
  3030 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3031 
  3032 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3033 instead);
  3034 
  3035 * HOL: the recursion equations generated by 'recdef' are now called
  3036 f.simps instead of f.rules;
  3037 
  3038 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3039 
  3040 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3041 sometimes be needed;
  3042 
  3043 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3044 
  3045 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3046 
  3047 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3048 product is now "<*>" instead of "Times"; the lexicographic product is
  3049 now "<*lex*>" instead of "**";
  3050 
  3051 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3052 of main HOL, but was unused); better use HOL's datatype package;
  3053 
  3054 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3055 the old syntax may be recovered as follows:
  3056 
  3057   syntax (symbols)
  3058     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3059       (infixl "\\<oplus>" 100)
  3060 
  3061 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3062 
  3063 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3064 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3065 internally;
  3066 
  3067 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3068 changed from A/r to A//r;
  3069 
  3070 * ZF: new treatment of arithmetic (nat & int) may break some old
  3071 proofs;
  3072 
  3073 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3074 rulify -> rule_format, elimify -> elim_format, ...);
  3075 
  3076 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3077 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3078 should have to change intro!! to intro? only); replaced "delrule" by
  3079 "rule del";
  3080 
  3081 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3082 
  3083 * Provers: strengthened force_tac by using new first_best_tac;
  3084 
  3085 * LaTeX document preparation: several changes of isabelle.sty (see
  3086 lib/texinputs);
  3087 
  3088 
  3089 *** Document preparation ***
  3090 
  3091 * formal comments (text blocks etc.) in new-style theories may now
  3092 contain antiquotations of thm/prop/term/typ/text to be presented
  3093 according to latex print mode; concrete syntax is like this:
  3094 @{term[show_types] "f(x) = a + x"};
  3095 
  3096 * isatool mkdir provides easy setup of Isabelle session directories,
  3097 including proper document sources;
  3098 
  3099 * generated LaTeX sources are now deleted after successful run
  3100 (isatool document -c); may retain a copy somewhere else via -D option
  3101 of isatool usedir;
  3102 
  3103 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3104 style files, achieving self-contained LaTeX sources and simplifying
  3105 LaTeX debugging;
  3106 
  3107 * old-style theories now produce (crude) LaTeX output as well;
  3108 
  3109 * browser info session directories are now self-contained (may be put
  3110 on WWW server seperately); improved graphs of nested sessions; removed
  3111 graph for 'all sessions';
  3112 
  3113 * several improvements in isabelle style files; \isabellestyle{it}
  3114 produces fake math mode output; \isamarkupheader is now \section by
  3115 default; see lib/texinputs/isabelle.sty etc.;
  3116 
  3117 
  3118 *** Isar ***
  3119 
  3120 * Isar/Pure: local results and corresponding term bindings are now
  3121 subject to Hindley-Milner polymorphism (similar to ML); this
  3122 accommodates incremental type-inference very nicely;
  3123 
  3124 * Isar/Pure: new derived language element 'obtain' supports
  3125 generalized existence reasoning;
  3126 
  3127 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3128 support accumulation of results, without applying any rules yet;
  3129 useful to collect intermediate results without explicit name
  3130 references, and for use with transitivity rules with more than 2
  3131 premises;
  3132 
  3133 * Isar/Pure: scalable support for case-analysis type proofs: new
  3134 'case' language element refers to local contexts symbolically, as
  3135 produced by certain proof methods; internally, case names are attached
  3136 to theorems as "tags";
  3137 
  3138 * Isar/Pure: theory command 'hide' removes declarations from
  3139 class/type/const name spaces;
  3140 
  3141 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3142 indicate potential overloading;
  3143 
  3144 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3145 
  3146 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3147 "{a,b,c}" instead of {a,b,c};
  3148 
  3149 * Isar/Pure now provides its own version of intro/elim/dest
  3150 attributes; useful for building new logics, but beware of confusion
  3151 with the version in Provers/classical;
  3152 
  3153 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3154 case name 'antecedent';
  3155 
  3156 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3157 to the current context is now done automatically);
  3158 
  3159 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3160 for definining proof methods in ML;
  3161 
  3162 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3163 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3164 most cases, one should have to change intro!! to intro? only);
  3165 replaced "delrule" by "rule del";
  3166 
  3167 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3168 'symmetric' attribute (the latter supercedes [RS sym]);
  3169 
  3170 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3171 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3172 well (including splits);
  3173 
  3174 * Isar/Provers: Simplifier and Classical methods now support all kind
  3175 of modifiers used in the past, including 'cong', 'iff', etc.
  3176 
  3177 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3178 of Simplifier and Classical reasoner);
  3179 
  3180 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3181 now support named cases; major packages (inductive, datatype, primrec,
  3182 recdef) support case names and properly name parameters;
  3183 
  3184 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3185 monotonicity conditions are extracted to be proven at end of
  3186 calculations;
  3187 
  3188 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3189 method anyway;
  3190 
  3191 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3192 split_if split_if_asm; datatype package provides theorems foo.splits =
  3193 foo.split foo.split_asm for each datatype;
  3194 
  3195 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3196 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3197 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3198 use "(cases (simplified))" method in proper proof texts);
  3199 
  3200 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3201 
  3202 * Isar: names of theorems etc. may be natural numbers as well;
  3203 
  3204 * Isar: 'pr' command: optional arguments for goals_limit and
  3205 ProofContext.prems_limit; no longer prints theory contexts, but only
  3206 proof states;
  3207 
  3208 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3209 additional print modes to be specified; e.g. "pr(latex)" will print
  3210 proof state according to the Isabelle LaTeX style;
  3211 
  3212 * Isar: improved support for emulating tactic scripts, including proof
  3213 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3214 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3215 (for HOL datatypes);
  3216 
  3217 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3218 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3219 'proof method scripts' have to be in depth-first order;
  3220 
  3221 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3222 
  3223 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3224 should instead use individual commands for printing items
  3225 (print_commands, print_methods etc.);
  3226 
  3227 * Isar: added 'nothing' --- the empty list of theorems;
  3228 
  3229 
  3230 *** HOL ***
  3231 
  3232 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3233 corresponding virtual machine and a specification of its bytecode
  3234 verifier and a lightweight bytecode verifier, including proofs of
  3235 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3236 Cornelia Pusch (see also the homepage of project Bali at
  3237 http://isabelle.in.tum.de/Bali/);
  3238 
  3239 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3240 Clemens Ballarin;
  3241 
  3242 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3243 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3244 Rasmussen;
  3245 
  3246 * HOL/Lattice: fundamental concepts of lattice theory and order
  3247 structures, including duals, properties of bounds versus algebraic
  3248 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3249 Theorem for complete lattices etc.; may also serve as a demonstration
  3250 for abstract algebraic reasoning using axiomatic type classes, and
  3251 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3252 
  3253 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3254 von Oheimb;
  3255 
  3256 * HOL/IMPP: extension of IMP with local variables and mutually
  3257 recursive procedures, by David von Oheimb;
  3258 
  3259 * HOL/Lambda: converted into new-style theory and document;
  3260 
  3261 * HOL/ex/Multiquote: example of multiple nested quotations and
  3262 anti-quotations -- basically a generalized version of de-Bruijn
  3263 representation; very useful in avoiding lifting of operations;
  3264 
  3265 * HOL/record: added general record equality rule to simpset; fixed
  3266 select-update simplification procedure to handle extended records as
  3267 well; admit "r" as field name;
  3268 
  3269 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3270 other numeric types and also as the identity of groups, rings, etc.;
  3271 
  3272 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3273 Types nat and int belong to this axclass;
  3274 
  3275 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3276    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3277    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3278   two terms #m*u and #n*u are replaced by #(m+n)*u
  3279     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3280   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3281     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3282 
  3283 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3284 powerful prover for predicate logic but knows nothing of clasets; see
  3285 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3286 
  3287 * HOL: new version of "case_tac" subsumes both boolean case split and
  3288 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3289 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3290 
  3291 * HOL: simplification no longer dives into case-expressions: only the
  3292 selector expression is simplified, but not the remaining arms; to
  3293 enable full simplification of case-expressions for datatype t, you may
  3294 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3295 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3296 
  3297 * HOL/recdef: the recursion equations generated by 'recdef' for
  3298 function 'f' are now called f.simps instead of f.rules; if all
  3299 termination conditions are proved automatically, these simplification
  3300 rules are added to the simpset, as in primrec; rules may be named
  3301 individually as well, resulting in a separate list of theorems for
  3302 each equation;
  3303 
  3304 * HOL/While is a new theory that provides a while-combinator. It
  3305 permits the definition of tail-recursive functions without the
  3306 provision of a termination measure. The latter is necessary once the
  3307 invariant proof rule for while is applied.
  3308 
  3309 * HOL: new (overloaded) notation for the set of elements below/above
  3310 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3311 
  3312 * HOL: theorems impI, allI, ballI bound as "strip";
  3313 
  3314 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3315 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3316 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3317 
  3318 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3319 
  3320 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3321 main HOL, but was unused);
  3322 
  3323 * HOL: fewer consts declared as global (e.g. have to refer to
  3324 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3325 
  3326 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3327 in case of overlap with user translations (e.g. judgements over
  3328 tuples); (note that the underlying logical represenation is still
  3329 bogus);
  3330 
  3331 
  3332 *** ZF ***
  3333 
  3334 * ZF: simplification automatically cancels common terms in arithmetic
  3335 expressions over nat and int;
  3336 
  3337 * ZF: new treatment of nat to minimize type-checking: all operators
  3338 coerce their operands to a natural number using the function natify,
  3339 making the algebraic laws unconditional;
  3340 
  3341 * ZF: as above, for int: operators coerce their operands to an integer
  3342 using the function intify;
  3343 
  3344 * ZF: the integer library now contains many of the usual laws for the
  3345 orderings, including $<=, and monotonicity laws for $+ and $*;
  3346 
  3347 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3348 simplification;
  3349 
  3350 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3351 to the simplifier and classical reasoner simultaneously;
  3352 
  3353 
  3354 *** General ***
  3355 
  3356 * Provers: blast_tac now handles actual object-logic rules as
  3357 assumptions; note that auto_tac uses blast_tac internally as well;
  3358 
  3359 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3360 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3361 
  3362 * Provers: delrules now handles destruct rules as well (no longer need
  3363 explicit make_elim);
  3364 
  3365 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3366   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3367 use instead the strong form,
  3368   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3369 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3370 from destruct-rules;
  3371 
  3372 * Provers: Simplifier.easy_setup provides a fast path to basic
  3373 Simplifier setup for new object-logics;
  3374 
  3375 * Pure: AST translation rules no longer require constant head on LHS;
  3376 
  3377 * Pure: improved name spaces: ambiguous output is qualified; support
  3378 for hiding of names;
  3379 
  3380 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3381 XSYMBOL_HOME; no longer need to do manual configuration in most
  3382 situations;
  3383 
  3384 * system: compression of ML heaps images may now be controlled via -c
  3385 option of isabelle and isatool usedir (currently only observed by
  3386 Poly/ML);
  3387 
  3388 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3389 useful for remote X11);
  3390 
  3391 * system: provide TAGS file for Isabelle sources;
  3392 
  3393 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3394 order;
  3395 
  3396 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3397 timing flag supersedes proof_timing and Toplevel.trace;
  3398 
  3399 * ML: new combinators |>> and |>>> for incremental transformations
  3400 with secondary results (e.g. certain theory extensions):
  3401 
  3402 * ML: PureThy.add_defs gets additional argument to indicate potential
  3403 overloading (usually false);
  3404 
  3405 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3406 results;
  3407 
  3408 
  3409 
  3410 New in Isabelle99 (October 1999)
  3411 --------------------------------
  3412 
  3413 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3414 
  3415 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3416 are no longer simplified.  (This allows the simplifier to unfold recursive
  3417 functional programs.)  To restore the old behaviour, declare
  3418 
  3419     Delcongs [if_weak_cong];
  3420 
  3421 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3422 complement;
  3423 
  3424 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3425 
  3426 * HOL/datatype: mutual_induct_tac no longer exists --
  3427   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3428 
  3429 * HOL/typedef: fixed type inference for representing set; type
  3430 arguments now have to occur explicitly on the rhs as type constraints;
  3431 
  3432 * ZF: The con_defs part of an inductive definition may no longer refer
  3433 to constants declared in the same theory;
  3434 
  3435 * HOL, ZF: the function mk_cases, generated by the inductive
  3436 definition package, has lost an argument.  To simplify its result, it
  3437 uses the default simpset instead of a supplied list of theorems.
  3438 
  3439 * HOL/List: the constructors of type list are now Nil and Cons;
  3440 
  3441 * Simplifier: the type of the infix ML functions
  3442         setSSolver addSSolver setSolver addSolver
  3443 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3444 for packaging solvers. A solver is created via
  3445         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3446 where the string argument is only a comment.
  3447 
  3448 
  3449 *** Proof tools ***
  3450 
  3451 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3452 decision procedure for linear arithmetic. Currently it is used for
  3453 types `nat', `int', and `real' in HOL (see below); it can, should and
  3454 will be instantiated for other types and logics as well.
  3455 
  3456 * The simplifier now accepts rewrite rules with flexible heads, eg
  3457      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3458   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3459   matching.
  3460 
  3461 
  3462 *** General ***
  3463 
  3464 * New Isabelle/Isar subsystem provides an alternative to traditional
  3465 tactical theorem proving; together with the ProofGeneral/isar user
  3466 interface it offers an interactive environment for developing human
  3467 readable proof documents (Isar == Intelligible semi-automated
  3468 reasoning); for further information see isatool doc isar-ref,
  3469 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3470 
  3471 * improved and simplified presentation of theories: better HTML markup
  3472 (including colors), graph views in several sizes; isatool usedir now
  3473 provides a proper interface for user theories (via -P option); actual
  3474 document preparation based on (PDF)LaTeX is available as well (for
  3475 new-style theories only); see isatool doc system for more information;
  3476 
  3477 * native support for Proof General, both for classic Isabelle and
  3478 Isabelle/Isar;
  3479 
  3480 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3481 using the graph browser tool;
  3482 
  3483 * Isabelle manuals now also available as PDF;
  3484 
  3485 * theory loader rewritten from scratch (may not be fully
  3486 bug-compatible); old loadpath variable has been replaced by show_path,
  3487 add_path, del_path, reset_path functions; new operations such as
  3488 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3489 isatool doc ref);
  3490 
  3491 * improved isatool install: option -k creates KDE application icon,
  3492 option -p DIR installs standalone binaries;
  3493 
  3494 * added ML_PLATFORM setting (useful for cross-platform installations);
  3495 more robust handling of platform specific ML images for SML/NJ;
  3496 
  3497 * the settings environment is now statically scoped, i.e. it is never
  3498 created again in sub-processes invoked from isabelle, isatool, or
  3499 Isabelle;
  3500 
  3501 * path element specification '~~' refers to '$ISABELLE_HOME';
  3502 
  3503 * in locales, the "assumes" and "defines" parts may be omitted if
  3504 empty;
  3505 
  3506 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3507 long arrows);
  3508 
  3509 * new print_mode "HTML";
  3510 
  3511 * new flag show_tags controls display of tags of theorems (which are
  3512 basically just comments that may be attached by some tools);
  3513 
  3514 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3515 mode and goal output format:
  3516 
  3517 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3518 244c244
  3519 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3520 ---
  3521 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3522 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3523 181c181
  3524 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3525 ---
  3526 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3527 
  3528 * function bind_thms stores lists of theorems (cf. bind_thm);
  3529 
  3530 * new shorthand tactics ftac, eatac, datac, fatac;
  3531 
  3532 * qed (and friends) now accept "" as result name; in that case the
  3533 theorem is not stored, but proper checks and presentation of the
  3534 result still apply;
  3535 
  3536 * theorem database now also indexes constants "Trueprop", "all",
  3537 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3538 
  3539 
  3540 *** HOL ***
  3541 
  3542 ** HOL arithmetic **
  3543 
  3544 * There are now decision procedures for linear arithmetic over nat and
  3545 int:
  3546 
  3547 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3548 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3549 are treated as atomic; subformulae not involving type `nat' or `int'
  3550 are ignored; quantified subformulae are ignored unless they are
  3551 positive universal or negative existential. The tactic has to be
  3552 invoked by hand and can be a little bit slow. In particular, the
  3553 running time is exponential in the number of occurrences of `min' and
  3554 `max', and `-' on `nat'.
  3555 
  3556 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3557 (negated) (in)equalities among the premises and the conclusion into
  3558 account (i.e. no compound formulae) and does not know about `min' and
  3559 `max', and `-' on `nat'. It is fast and is used automatically by the
  3560 simplifier.
  3561 
  3562 NB: At the moment, these decision procedures do not cope with mixed
  3563 nat/int formulae where the two parts interact, such as `m < n ==>
  3564 int(m) < int(n)'.
  3565 
  3566 * HOL/Numeral provides a generic theory of numerals (encoded
  3567 efficiently as bit strings); setup for types nat/int/real is in place;
  3568 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3569 int, existing theories and proof scripts may require a few additional
  3570 type constraints;
  3571 
  3572 * integer division and remainder can now be performed on constant
  3573 arguments;
  3574 
  3575 * many properties of integer multiplication, division and remainder
  3576 are now available;
  3577 
  3578 * An interface to the Stanford Validity Checker (SVC) is available through the
  3579 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3580 are proved automatically.  SVC must be installed separately, and its results
  3581 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3582 invocation of the underlying oracle).  For SVC see
  3583   http://verify.stanford.edu/SVC
  3584 
  3585 * IsaMakefile: the HOL-Real target now builds an actual image;
  3586 
  3587 
  3588 ** HOL misc **
  3589 
  3590 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3591 (in Isabelle/Isar) -- by Gertrud Bauer;
  3592 
  3593 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3594 analysis for assembly languages with subtypes;
  3595 
  3596 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3597 -- avoids syntactic ambiguities and treats state, transition, and
  3598 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3599 changed syntax and (many) tactics;
  3600 
  3601 * HOL/inductive: Now also handles more general introduction rules such
  3602   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3603   theorems are now maintained within the theory (maintained via the
  3604   "mono" attribute);
  3605 
  3606 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3607   (using function types) such as
  3608 
  3609   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3610 
  3611 * HOL/record: record_simproc (part of the default simpset) takes care
  3612 of selectors applied to updated records; record_split_tac is no longer
  3613 part of the default claset; update_defs may now be removed from the
  3614 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3615 
  3616   claset_ref () := claset() addSWrapper record_split_wrapper;
  3617   Delsimprocs [record_simproc]
  3618 
  3619 * HOL/typedef: fixed type inference for representing set; type
  3620 arguments now have to occur explicitly on the rhs as type constraints;
  3621 
  3622 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3623 names rather than an ML expression;
  3624 
  3625 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3626 supplied later.  Program schemes can be defined, such as
  3627     "While B C s = (if B s then While B C (C s) else s)"
  3628 where the well-founded relation can be chosen after B and C have been given.
  3629 
  3630 * HOL/List: the constructors of type list are now Nil and Cons;
  3631 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3632 course, ML tools referring to List.list.op # etc. have to be adapted;
  3633 
  3634 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3635 disabled by default; run isabelle with option -m HOL to get back to
  3636 the original Gordon/HOL-style output;
  3637 
  3638 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3639 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3640 
  3641 * HOL basic syntax simplified (more orthogonal): all variants of
  3642 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3643 Eps operator is provided as well: "SOME x. P[x]";
  3644 
  3645 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3646 
  3647 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3648 thus available for user theories;
  3649 
  3650 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3651 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3652 time;
  3653 
  3654 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3655 several times and then mp;
  3656 
  3657 
  3658 *** LK ***
  3659 
  3660 * the notation <<...>> is now available as a notation for sequences of
  3661 formulas;
  3662 
  3663 * the simplifier is now installed
  3664 
  3665 * the axiom system has been generalized (thanks to Soren Heilmann)
  3666 
  3667 * the classical reasoner now has a default rule database
  3668 
  3669 
  3670 *** ZF ***
  3671 
  3672 * new primrec section allows primitive recursive functions to be given
  3673 directly (as in HOL) over datatypes and the natural numbers;
  3674 
  3675 * new tactics induct_tac and exhaust_tac for induction (or case
  3676 analysis) over datatypes and the natural numbers;
  3677 
  3678 * the datatype declaration of type T now defines the recursor T_rec;
  3679 
  3680 * simplification automatically does freeness reasoning for datatype
  3681 constructors;
  3682 
  3683 * automatic type-inference, with AddTCs command to insert new
  3684 type-checking rules;
  3685 
  3686 * datatype introduction rules are now added as Safe Introduction rules
  3687 to the claset;
  3688 
  3689 * the syntax "if P then x else y" is now available in addition to
  3690 if(P,x,y);
  3691 
  3692 
  3693 *** Internal programming interfaces ***
  3694 
  3695 * tuned simplifier trace output; new flag debug_simp;
  3696 
  3697 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3698 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3699 
  3700 * AxClass.axclass_tac lost the theory argument;
  3701 
  3702 * tuned current_goals_markers semantics: begin / end goal avoids
  3703 printing empty lines;
  3704 
  3705 * removed prs and prs_fn hook, which was broken because it did not
  3706 include \n in its semantics, forcing writeln to add one
  3707 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3708 string -> unit if you really want to output text without newline;
  3709 
  3710 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3711 plain output, interface builders may have to enable 'isabelle_font'
  3712 mode to get Isabelle font glyphs as before;
  3713 
  3714 * refined token_translation interface; INCOMPATIBILITY: output length
  3715 now of type real instead of int;
  3716 
  3717 * theory loader actions may be traced via new ThyInfo.add_hook
  3718 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3719 your own database of information attached to *whole* theories -- as
  3720 opposed to intra-theory data slots offered via TheoryDataFun;
  3721 
  3722 * proper handling of dangling sort hypotheses (at last!);
  3723 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3724 extra sort hypotheses that can be witnessed from the type signature;
  3725 the force_strip_shyps flag is gone, any remaining shyps are simply
  3726 left in the theorem (with a warning issued by strip_shyps_warning);
  3727 
  3728 
  3729 
  3730 New in Isabelle98-1 (October 1998)
  3731 ----------------------------------
  3732 
  3733 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3734 
  3735 * several changes of automated proof tools;
  3736 
  3737 * HOL: major changes to the inductive and datatype packages, including
  3738 some minor incompatibilities of theory syntax;
  3739 
  3740 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3741 called `inj_on';
  3742 
  3743 * HOL: removed duplicate thms in Arith:
  3744   less_imp_add_less  should be replaced by  trans_less_add1
  3745   le_imp_add_le      should be replaced by  trans_le_add1
  3746 
  3747 * HOL: unary minus is now overloaded (new type constraints may be
  3748 required);
  3749 
  3750 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3751 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3752 now taken as an integer constant.
  3753 
  3754 * Pure: ML function 'theory_of' renamed to 'theory';
  3755 
  3756 
  3757 *** Proof tools ***
  3758 
  3759 * Simplifier:
  3760   1. Asm_full_simp_tac is now more aggressive.
  3761      1. It will sometimes reorient premises if that increases their power to
  3762         simplify.
  3763      2. It does no longer proceed strictly from left to right but may also
  3764         rotate premises to achieve further simplification.
  3765      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3766      old Asm_full_simp_tac in that it does not rotate premises.
  3767   2. The simplifier now knows a little bit about nat-arithmetic.
  3768 
  3769 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3770 allows for selected deletion of wrappers, by introduction of names for
  3771 wrapper functionals.  This implies that addbefore, addSbefore,
  3772 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3773 and that adding two tactics with the same name overwrites the first
  3774 one (emitting a warning).
  3775   type wrapper = (int -> tactic) -> (int -> tactic)
  3776   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3777   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3778   delWrapper, delSWrapper: claset *  string            -> claset
  3779   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3780 
  3781 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3782 semantics; addbefore now affects only the unsafe part of step_tac
  3783 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3784 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3785 by Force_tac;
  3786 
  3787 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3788 compWrapper; added safe wrapper (and access functions for it);
  3789 
  3790 * HOL/split_all_tac is now much faster and fails if there is nothing
  3791 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3792 and the names of the automatically generated variables have changed.
  3793 split_all_tac has moved within claset() from unsafe wrappers to safe
  3794 wrappers, which means that !!-bound variables are split much more
  3795 aggressively, and safe_tac and clarify_tac now split such variables.
  3796 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3797 Note: the same holds for record_split_tac, which does the job of
  3798 split_all_tac for record fields.
  3799 
  3800 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3801 permanently to the default simpset using Addsplits just like
  3802 Addsimps. They can be removed via Delsplits just like
  3803 Delsimps. Lower-case versions are also available.
  3804 
  3805 * HOL/Simplifier: The rule split_if is now part of the default
  3806 simpset. This means that the simplifier will eliminate all occurrences
  3807 of if-then-else in the conclusion of a goal. To prevent this, you can
  3808 either remove split_if completely from the default simpset by
  3809 `Delsplits [split_if]' or remove it in a specific call of the
  3810 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3811 other case splitting rules to/from the default simpset: every datatype
  3812 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3813 t is the name of the datatype).
  3814 
  3815 * Classical reasoner / Simplifier combination: new force_tac (and
  3816 derivatives Force_tac, force) combines rewriting and classical
  3817 reasoning (and whatever other tools) similarly to auto_tac, but is
  3818 aimed to solve the given subgoal completely.
  3819 
  3820 
  3821 *** General ***
  3822 
  3823 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3824 and `goalw': the theory is no longer needed as an explicit argument -
  3825 the current theory context is used; assumptions are no longer returned
  3826 at the ML-level unless one of them starts with ==> or !!; it is
  3827 recommended to convert to these new commands using isatool fixgoal
  3828 (backup your sources first!);
  3829 
  3830 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3831 the current theory context, and 'theory' to lookup stored theories;
  3832 
  3833 * new theory section 'locale' for declaring constants, assumptions and
  3834 definitions that have local scope;
  3835 
  3836 * new theory section 'nonterminals' for purely syntactic types;
  3837 
  3838 * new theory section 'setup' for generic ML setup functions
  3839 (e.g. package initialization);
  3840 
  3841 * the distribution now includes Isabelle icons: see
  3842 lib/logo/isabelle-{small,tiny}.xpm;
  3843 
  3844 * isatool install - install binaries with absolute references to
  3845 ISABELLE_HOME/bin;
  3846 
  3847 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3848 
  3849 * print mode 'emacs' reserved for Isamode;
  3850 
  3851 * support multiple print (ast) translations per constant name;
  3852 
  3853 * theorems involving oracles are now printed with a suffixed [!];
  3854 
  3855 
  3856 *** HOL ***
  3857 
  3858 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3859 
  3860 * HOL/inductive package reorganized and improved: now supports mutual
  3861 definitions such as
  3862 
  3863   inductive EVEN ODD
  3864     intrs
  3865       null "0 : EVEN"
  3866       oddI "n : EVEN ==> Suc n : ODD"
  3867       evenI "n : ODD ==> Suc n : EVEN"
  3868 
  3869 new theorem list "elims" contains an elimination rule for each of the
  3870 recursive sets; inductive definitions now handle disjunctive premises
  3871 correctly (also ZF);
  3872 
  3873 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3874 "mutual_induct" no longer exists - the induction rule is always
  3875 contained in "induct";
  3876 
  3877 
  3878 * HOL/datatype package re-implemented and greatly improved: now
  3879 supports mutually recursive datatypes such as
  3880 
  3881   datatype
  3882     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3883             | SUM ('a aexp) ('a aexp)
  3884             | DIFF ('a aexp) ('a aexp)
  3885             | NUM 'a
  3886   and
  3887     'a bexp = LESS ('a aexp) ('a aexp)
  3888             | AND ('a bexp) ('a bexp)
  3889             | OR ('a bexp) ('a bexp)
  3890 
  3891 as well as indirectly recursive datatypes such as
  3892 
  3893   datatype
  3894     ('a, 'b) term = Var 'a
  3895                   | App 'b ((('a, 'b) term) list)
  3896 
  3897 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3898 induction on mutually / indirectly recursive datatypes.
  3899 
  3900 Primrec equations are now stored in theory and can be accessed via
  3901 <function_name>.simps.
  3902 
  3903 INCOMPATIBILITIES:
  3904 
  3905   - Theories using datatypes must now have theory Datatype as an
  3906     ancestor.
  3907   - The specific <typename>.induct_tac no longer exists - use the
  3908     generic induct_tac instead.
  3909   - natE has been renamed to nat.exhaust - use exhaust_tac
  3910     instead of res_inst_tac ... natE. Note that the variable
  3911     names in nat.exhaust differ from the names in natE, this
  3912     may cause some "fragile" proofs to fail.
  3913   - The theorems split_<typename>_case and split_<typename>_case_asm
  3914     have been renamed to <typename>.split and <typename>.split_asm.
  3915   - Since default sorts of type variables are now handled correctly,
  3916     some datatype definitions may have to be annotated with explicit
  3917     sort constraints.
  3918   - Primrec definitions no longer require function name and type
  3919     of recursive argument.
  3920 
  3921 Consider using isatool fixdatatype to adapt your theories and proof
  3922 scripts to the new package (backup your sources first!).
  3923 
  3924 
  3925 * HOL/record package: considerably improved implementation; now
  3926 includes concrete syntax for record types, terms, updates; theorems
  3927 for surjective pairing and splitting !!-bound record variables; proof
  3928 support is as follows:
  3929 
  3930   1) standard conversions (selectors or updates applied to record
  3931 constructor terms) are part of the standard simpset;
  3932 
  3933   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3934 made part of standard simpset and claset via addIffs;
  3935 
  3936   3) a tactic for record field splitting (record_split_tac) is part of
  3937 the standard claset (addSWrapper);
  3938 
  3939 To get a better idea about these rules you may retrieve them via
  3940 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3941 the name of your record type.
  3942 
  3943 The split tactic 3) conceptually simplifies by the following rule:
  3944 
  3945   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3946 
  3947 Thus any record variable that is bound by meta-all will automatically
  3948 blow up into some record constructor term, consequently the
  3949 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3950 solve record problems automatically.
  3951 
  3952 
  3953 * reorganized the main HOL image: HOL/Integ and String loaded by
  3954 default; theory Main includes everything;
  3955 
  3956 * automatic simplification of integer sums and comparisons, using cancellation;
  3957 
  3958 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3959 
  3960 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3961 
  3962 * many new identities for unions, intersections, set difference, etc.;
  3963 
  3964 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3965 called split_if, split_split, split_sum_case and split_nat_case (to go
  3966 with add/delsplits);
  3967 
  3968 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3969 (?x::unit) = (); this is made part of the default simpset, which COULD
  3970 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3971 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3972 unit_abs_eta_conv is added in order to counter the effect of
  3973 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3974 %u.f();
  3975 
  3976 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3977 makes more sense);
  3978 
  3979 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3980   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3981   disjointness reasoning but breaking a few old proofs.
  3982 
  3983 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3984 to 'converse' from 'inverse' (for compatibility with ZF and some
  3985 literature);
  3986 
  3987 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3988 the well-founded relation;
  3989 
  3990 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3991     Compl A.  The "Compl" syntax remains available as input syntax for this
  3992     release ONLY.
  3993 
  3994 * HOL/Update: new theory of function updates:
  3995     f(a:=b) == %x. if x=a then b else f x
  3996 may also be iterated as in f(a:=b,c:=d,...);
  3997 
  3998 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3999 
  4000 * HOL/List:
  4001   - new function list_update written xs[i:=v] that updates the i-th
  4002     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4003   - new function `upt' written [i..j(] which generates the list
  4004     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4005     bound write [i..j], which is a shorthand for [i..j+1(].
  4006   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4007 
  4008 * HOL/Arith:
  4009   - removed 'pred' (predecessor) function;
  4010   - generalized some theorems about n-1;
  4011   - many new laws about "div" and "mod";
  4012   - new laws about greatest common divisors (see theory ex/Primes);
  4013 
  4014 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4015 instead of "inverse";
  4016 
  4017 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4018   of the multiset ordering;
  4019 
  4020 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4021   (not included by default);
  4022 
  4023 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4024 
  4025 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4026   programs, i.e. different program variables may have different types.
  4027 
  4028 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4029   [previously, this check worked only if the rewrite rule was unconditional]
  4030   Now rew can involve either definitions or equalities (either == or =).
  4031 
  4032 
  4033 *** ZF ***
  4034 
  4035 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4036   only the theorems proved on ZF.ML;
  4037 
  4038 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4039   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4040   disjointness reasoning but breaking a few old proofs.
  4041 
  4042 * ZF/Update: new theory of function updates
  4043     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4044   may also be iterated as in f(a:=b,c:=d,...);
  4045 
  4046 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4047 
  4048 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4049   [previously, this check worked only if the rewrite rule was unconditional]
  4050   Now rew can involve either definitions or equalities (either == or =).
  4051 
  4052 * case_tac provided for compatibility with HOL
  4053     (like the old excluded_middle_tac, but with subgoals swapped)
  4054 
  4055 
  4056 *** Internal programming interfaces ***
  4057 
  4058 * Pure: several new basic modules made available for general use, see
  4059 also src/Pure/README;
  4060 
  4061 * improved the theory data mechanism to support encapsulation (data
  4062 kind name replaced by private Object.kind, acting as authorization
  4063 key); new type-safe user interface via functor TheoryDataFun; generic
  4064 print_data function becomes basically useless;
  4065 
  4066 * removed global_names compatibility flag -- all theory declarations
  4067 are qualified by default;
  4068 
  4069 * module Pure/Syntax now offers quote / antiquote translation
  4070 functions (useful for Hoare logic etc. with implicit dependencies);
  4071 see HOL/ex/Antiquote for an example use;
  4072 
  4073 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4074 cterm -> thm;
  4075 
  4076 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4077 subgoal;
  4078 
  4079 * Display.print_goals function moved to Locale.print_goals;
  4080 
  4081 * standard print function for goals supports current_goals_markers
  4082 variable for marking begin of proof, end of proof, start of goal; the
  4083 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4084 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4085 for example;
  4086 
  4087 
  4088 
  4089 New in Isabelle98 (January 1998)
  4090 --------------------------------
  4091 
  4092 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4093 
  4094 * changed lexical syntax of terms / types: dots made part of long
  4095 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4096 
  4097 * simpset (and claset) reference variable replaced by functions
  4098 simpset / simpset_ref;
  4099 
  4100 * no longer supports theory aliases (via merge) and non-trivial
  4101 implicit merge of thms' signatures;
  4102 
  4103 * most internal names of constants changed due to qualified names;
  4104 
  4105 * changed Pure/Sequence interface (see Pure/seq.ML);
  4106 
  4107 
  4108 *** General Changes ***
  4109 
  4110 * hierachically structured name spaces (for consts, types, axms, thms
  4111 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4112 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4113 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4114 long_names for fully qualified output names; NOTE: ML programs
  4115 (special tactics, packages etc.) referring to internal names may have
  4116 to be adapted to cope with fully qualified names; in case of severe
  4117 backward campatibility problems try setting 'global_names' at compile
  4118 time to have enrything declared within a flat name space; one may also
  4119 fine tune name declarations in theories via the 'global' and 'local'
  4120 section;
  4121 
  4122 * reimplemented the implicit simpset and claset using the new anytype
  4123 data filed in signatures; references simpset:simpset ref etc. are
  4124 replaced by functions simpset:unit->simpset and
  4125 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4126 to patch your ML files accordingly;
  4127 
  4128 * HTML output now includes theory graph data for display with Java
  4129 applet or isatool browser; data generated automatically via isatool
  4130 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4131 
  4132 * defs may now be conditional; improved rewrite_goals_tac to handle
  4133 conditional equations;
  4134 
  4135 * defs now admits additional type arguments, using TYPE('a) syntax;
  4136 
  4137 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4138 creates a new theory node; implicit merge of thms' signatures is
  4139 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4140 transfer:theory->thm->thm in (rare) cases;
  4141 
  4142 * improved handling of draft signatures / theories; draft thms (and
  4143 ctyps, cterms) are automatically promoted to real ones;
  4144 
  4145 * slightly changed interfaces for oracles: admit many per theory, named
  4146 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4147 
  4148 * print_goals: optional output of const types (set show_consts and
  4149 show_types);
  4150 
  4151 * improved output of warnings (###) and errors (***);
  4152 
  4153 * subgoal_tac displays a warning if the new subgoal has type variables;
  4154 
  4155 * removed old README and Makefiles;
  4156 
  4157 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4158 
  4159 * removed obsolete init_pps and init_database;
  4160 
  4161 * deleted the obsolete tactical STATE, which was declared by
  4162     fun STATE tacfun st = tacfun st st;
  4163 
  4164 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4165 (which abbreviates $HOME);
  4166 
  4167 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4168 use isatool fixseq to adapt your ML programs (this works for fully
  4169 qualified references to the Sequence structure only!);
  4170 
  4171 * use_thy no longer requires writable current directory; it always
  4172 reloads .ML *and* .thy file, if either one is out of date;
  4173 
  4174 
  4175 *** Classical Reasoner ***
  4176 
  4177 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4178 tactics that use classical reasoning to simplify a subgoal without
  4179 splitting it into several subgoals;
  4180 
  4181 * Safe_tac: like safe_tac but uses the default claset;
  4182 
  4183 
  4184 *** Simplifier ***
  4185 
  4186 * added simplification meta rules:
  4187     (asm_)(full_)simplify: simpset -> thm -> thm;
  4188 
  4189 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4190 logics (again);
  4191 
  4192 * added prems argument to simplification procedures;
  4193 
  4194 * HOL, FOL, ZF: added infix function `addsplits':
  4195   instead of `<simpset> setloop (split_tac <thms>)'
  4196   you can simply write `<simpset> addsplits <thms>'
  4197 
  4198 
  4199 *** Syntax ***
  4200 
  4201 * TYPE('a) syntax for type reflection terms;
  4202 
  4203 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4204 
  4205 * pretty printer: changed order of mixfix annotation preference (again!);
  4206 
  4207 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4208 
  4209 
  4210 *** HOL ***
  4211 
  4212 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4213   with `addloop' of the simplifier to faciliate case splitting in premises.
  4214 
  4215 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4216 
  4217 * HOL/Auth: new protocol proofs including some for the Internet
  4218   protocol TLS;
  4219 
  4220 * HOL/Map: new theory of `maps' a la VDM;
  4221 
  4222 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4223 cancelling out common nat summands from =, <, <= (in)equalities, or
  4224 differences; simplification procedures nat_cancel_factor for
  4225 cancelling common factor from =, <, <= (in)equalities over natural
  4226 sums; nat_cancel contains both kinds of procedures, it is installed by
  4227 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4228 
  4229 * HOL/simplifier: terms of the form
  4230   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4231   are rewritten to
  4232   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4233   and those of the form
  4234   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4235   are rewritten to
  4236   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4237 
  4238 * HOL/datatype
  4239   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4240 
  4241   P(t_case f1 ... fn x) =
  4242      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4243         ...
  4244        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4245      )
  4246 
  4247   and a theorem `split_t_case_asm' of the form
  4248 
  4249   P(t_case f1 ... fn x) =
  4250     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4251         ...
  4252        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4253      )
  4254   which can be added to a simpset via `addsplits'. The existing theorems
  4255   expand_list_case and expand_option_case have been renamed to
  4256   split_list_case and split_option_case.
  4257 
  4258 * HOL/Arithmetic:
  4259   - `pred n' is automatically converted to `n-1'.
  4260     Users are strongly encouraged not to use `pred' any longer,
  4261     because it will disappear altogether at some point.
  4262   - Users are strongly encouraged to write "0 < n" rather than
  4263     "n ~= 0". Theorems and proof tools have been modified towards this
  4264     `standard'.
  4265 
  4266 * HOL/Lists:
  4267   the function "set_of_list" has been renamed "set" (and its theorems too);
  4268   the function "nth" now takes its arguments in the reverse order and
  4269   has acquired the infix notation "!" as in "xs!n".
  4270 
  4271 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4272 
  4273 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4274   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4275 
  4276 * HOL/record: extensible records with schematic structural subtyping
  4277 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4278 still lacks various theorems and concrete record syntax;
  4279 
  4280 
  4281 *** HOLCF ***
  4282 
  4283 * removed "axioms" and "generated by" sections;
  4284 
  4285 * replaced "ops" section by extended "consts" section, which is capable of
  4286   handling the continuous function space "->" directly;
  4287 
  4288 * domain package:
  4289   . proves theorems immediately and stores them in the theory,
  4290   . creates hierachical name space,
  4291   . now uses normal mixfix annotations (instead of cinfix...),
  4292   . minor changes to some names and values (for consistency),
  4293   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4294   . separator between mutual domain defs: changed "," to "and",
  4295   . improved handling of sort constraints;  now they have to
  4296     appear on the left-hand side of the equations only;
  4297 
  4298 * fixed LAM <x,y,zs>.b syntax;
  4299 
  4300 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4301 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4302 
  4303 
  4304 *** FOL and ZF ***
  4305 
  4306 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4307   with `addloop' of the simplifier to faciliate case splitting in premises.
  4308 
  4309 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4310 in HOL, they strip ALL and --> from proved theorems;
  4311 
  4312 
  4313 
  4314 New in Isabelle94-8 (May 1997)
  4315 ------------------------------
  4316 
  4317 *** General Changes ***
  4318 
  4319 * new utilities to build / run / maintain Isabelle etc. (in parts
  4320 still somewhat experimental); old Makefiles etc. still functional;
  4321 
  4322 * new 'Isabelle System Manual';
  4323 
  4324 * INSTALL text, together with ./configure and ./build scripts;
  4325 
  4326 * reimplemented type inference for greater efficiency, better error
  4327 messages and clean internal interface;
  4328 
  4329 * prlim command for dealing with lots of subgoals (an easier way of
  4330 setting goals_limit);
  4331 
  4332 
  4333 *** Syntax ***
  4334 
  4335 * supports alternative (named) syntax tables (parser and pretty
  4336 printer); internal interface is provided by add_modesyntax(_i);
  4337 
  4338 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4339 be used in conjunction with the Isabelle symbol font; uses the
  4340 "symbols" syntax table;
  4341 
  4342 * added token_translation interface (may translate name tokens in
  4343 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4344 the current print_mode); IMPORTANT: user print translation functions
  4345 are responsible for marking newly introduced bounds
  4346 (Syntax.mark_boundT);
  4347 
  4348 * token translations for modes "xterm" and "xterm_color" that display
  4349 names in bold, underline etc. or colors (which requires a color
  4350 version of xterm);
  4351 
  4352 * infixes may now be declared with names independent of their syntax;
  4353 
  4354 * added typed_print_translation (like print_translation, but may
  4355 access type of constant);
  4356 
  4357 
  4358 *** Classical Reasoner ***
  4359 
  4360 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4361 some limitations.  Blast_tac...
  4362   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4363   + ignores elimination rules that don't have the correct format
  4364         (the conclusion MUST be a formula variable)
  4365   + ignores types, which can make HOL proofs fail
  4366   + rules must not require higher-order unification, e.g. apply_type in ZF
  4367     [message "Function Var's argument not a bound variable" relates to this]
  4368   + its proof strategy is more general but can actually be slower
  4369 
  4370 * substitution with equality assumptions no longer permutes other
  4371 assumptions;
  4372 
  4373 * minor changes in semantics of addafter (now called addaltern); renamed
  4374 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4375 (and access functions for it);
  4376 
  4377 * improved combination of classical reasoner and simplifier:
  4378   + functions for handling clasimpsets
  4379   + improvement of addss: now the simplifier is called _after_ the
  4380     safe steps.
  4381   + safe variant of addss called addSss: uses safe simplifications
  4382     _during_ the safe steps. It is more complete as it allows multiple
  4383     instantiations of unknowns (e.g. with slow_tac).
  4384 
  4385 *** Simplifier ***
  4386 
  4387 * added interface for simplification procedures (functions that
  4388 produce *proven* rewrite rules on the fly, depending on current
  4389 redex);
  4390 
  4391 * ordering on terms as parameter (used for ordered rewriting);
  4392 
  4393 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4394 
  4395 * the solver is now split into a safe and an unsafe part.
  4396 This should be invisible for the normal user, except that the
  4397 functions setsolver and addsolver have been renamed to setSolver and
  4398 addSolver; added safe_asm_full_simp_tac;
  4399 
  4400 
  4401 *** HOL ***
  4402 
  4403 * a generic induction tactic `induct_tac' which works for all datatypes and
  4404 also for type `nat';
  4405 
  4406 * a generic case distinction tactic `exhaust_tac' which works for all
  4407 datatypes and also for type `nat';
  4408 
  4409 * each datatype comes with a function `size';
  4410 
  4411 * patterns in case expressions allow tuple patterns as arguments to
  4412 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4413 
  4414 * primrec now also works with type nat;
  4415 
  4416 * recdef: a new declaration form, allows general recursive functions to be
  4417 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4418 
  4419 * the constant for negation has been renamed from "not" to "Not" to
  4420 harmonize with FOL, ZF, LK, etc.;
  4421 
  4422 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4423 infinite lists;
  4424 
  4425 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4426 
  4427 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4428 problems in commutative rings, using axiomatic type classes for + and *;
  4429 
  4430 * more examples in HOL/MiniML and HOL/Auth;
  4431 
  4432 * more default rewrite rules for quantifiers, union/intersection;
  4433 
  4434 * a new constant `arbitrary == @x.False';
  4435 
  4436 * HOLCF/IOA replaces old HOL/IOA;
  4437 
  4438 * HOLCF changes: derived all rules and arities
  4439   + axiomatic type classes instead of classes
  4440   + typedef instead of faking type definitions
  4441   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4442   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4443   + eliminated the types void, one, tr
  4444   + use unit lift and bool lift (with translations) instead of one and tr
  4445   + eliminated blift from Lift3.thy (use Def instead of blift)
  4446   all eliminated rules are derived as theorems --> no visible changes ;
  4447 
  4448 
  4449 *** ZF ***
  4450 
  4451 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4452 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4453 as ZF_cs addSIs [equalityI];
  4454 
  4455 
  4456 
  4457 New in Isabelle94-7 (November 96)
  4458 ---------------------------------
  4459 
  4460 * allowing negative levels (as offsets) in prlev and choplev;
  4461 
  4462 * super-linear speedup for large simplifications;
  4463 
  4464 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4465 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4466 FAIL); can suppress it using the command Delsimps (ex_simps @
  4467 all_simps); De Morgan laws are also now included, by default;
  4468 
  4469 * improved printing of ==>  :  ~:
  4470 
  4471 * new object-logic "Sequents" adds linear logic, while replacing LK
  4472 and Modal (thanks to Sara Kalvala);
  4473 
  4474 * HOL/Auth: correctness proofs for authentication protocols;
  4475 
  4476 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4477 examples on HOL/Auth);
  4478 
  4479 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4480 the rewriter and classical reasoner simultaneously;
  4481 
  4482 * function uresult no longer returns theorems in "standard" format;
  4483 regain previous version by: val uresult = standard o uresult;
  4484 
  4485 
  4486 
  4487 New in Isabelle94-6
  4488 -------------------
  4489 
  4490 * oracles -- these establish an interface between Isabelle and trusted
  4491 external reasoners, which may deliver results as theorems;
  4492 
  4493 * proof objects (in particular record all uses of oracles);
  4494 
  4495 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4496 
  4497 * "constdefs" section in theory files;
  4498 
  4499 * "primrec" section (HOL) no longer requires names;
  4500 
  4501 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4502 
  4503 
  4504 
  4505 New in Isabelle94-5
  4506 -------------------
  4507 
  4508 * reduced space requirements;
  4509 
  4510 * automatic HTML generation from theories;
  4511 
  4512 * theory files no longer require "..." (quotes) around most types;
  4513 
  4514 * new examples, including two proofs of the Church-Rosser theorem;
  4515 
  4516 * non-curried (1994) version of HOL is no longer distributed;
  4517 
  4518 
  4519 
  4520 New in Isabelle94-4
  4521 -------------------
  4522 
  4523 * greatly reduced space requirements;
  4524 
  4525 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4526 
  4527 * searchable theorem database (see the section "Retrieving theorems" on
  4528 page 8 of the Reference Manual);
  4529 
  4530 * new examples, including Grabczewski's monumental case study of the
  4531 Axiom of Choice;
  4532 
  4533 * The previous version of HOL renamed to Old_HOL;
  4534 
  4535 * The new version of HOL (previously called CHOL) uses a curried syntax
  4536 for functions.  Application looks like f a b instead of f(a,b);
  4537 
  4538 * Mutually recursive inductive definitions finally work in HOL;
  4539 
  4540 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4541 translates to the operator "split";
  4542 
  4543 
  4544 
  4545 New in Isabelle94-3
  4546 -------------------
  4547 
  4548 * new infix operator, addss, allowing the classical reasoner to
  4549 perform simplification at each step of its search.  Example:
  4550         fast_tac (cs addss ss)
  4551 
  4552 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4553 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4554 look like (a,b) instead of <a,b>;
  4555 
  4556 * PLEASE NOTE: CHOL will eventually replace HOL!
  4557 
  4558 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4559 It translates to the operator "split".  A new theory of integers is available;
  4560 
  4561 * In ZF, integer numerals now denote two's-complement binary integers.
  4562 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4563 
  4564 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4565 of the Axiom of Choice;
  4566 
  4567 
  4568 
  4569 New in Isabelle94-2
  4570 -------------------
  4571 
  4572 * Significantly faster resolution;
  4573 
  4574 * the different sections in a .thy file can now be mixed and repeated
  4575 freely;
  4576 
  4577 * Database of theorems for FOL, HOL and ZF.  New
  4578 commands including qed, qed_goal and bind_thm store theorems in the database.
  4579 
  4580 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4581 a given theory (thms_of), or find out what theory a theorem was proved in
  4582 (theory_of_thm);
  4583 
  4584 * Bugs fixed in the inductive definition and datatype packages;
  4585 
  4586 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4587 and HOL_dup_cs obsolete;
  4588 
  4589 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4590 have been removed;
  4591 
  4592 * Simpler definition of function space in ZF;
  4593 
  4594 * new results about cardinal and ordinal arithmetic in ZF;
  4595 
  4596 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4597 types;
  4598 
  4599 
  4600 $Id$