NEWS
author wenzelm
Fri Dec 29 17:24:46 2006 +0100 (2006-12-29)
changeset 21935 4e20a5397b57
parent 21896 9a7949815a84
child 21960 0574f192b78a
permissions -rw-r--r--
renamed project to subgraph, improved presentation, avoided unnecessary evaluation of predicate;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: some popular names (e.g. "class", "fun", "help",
    19 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    20 
    21 * Legacy goal package: reduced interface to the bare minimum required
    22 to keep existing proof scripts running.  Most other user-level
    23 functions are now part of the OldGoals structure, which is *not* open
    24 by default (consider isatool expandshort before open OldGoals).
    25 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    26 these tend to cause confusion about the actual goal (!) context being
    27 used here, which is not necessarily the same as the_context().
    28 
    29 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    30 
    31 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    32 by default, which means that "prems" (and also "fixed variables") are
    33 suppressed from proof state output.  Note that the ProofGeneral
    34 settings mechanism allows to change and save options persistently, but
    35 older versions of Isabelle will fail to start up if a negative prems
    36 limit is imposed.
    37 
    38 * Local theory targets may be specified by non-nested blocks of
    39 ``context/locale/class ... begin'' followed by ``end''.  The body may
    40 contain definitions, theorems etc., including any derived mechanism
    41 that has been implemented on top of these primitives.  This concept
    42 generalizes the existing ``theorem (in ...)'' towards more versatility
    43 and scalability.
    44 
    45 
    46 *** Document preparation ***
    47 
    48 * Added antiquotation @{theory name} which prints the given name,
    49 after checking that it refers to a valid ancestor theory in the
    50 current context.
    51 
    52 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    53 check the given source text as ML type/structure, printing verbatim.
    54 
    55 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    56 "c args == rhs" given in the current context.  (Any number of
    57 arguments may be given on the LHS.)
    58 
    59 
    60 
    61 *** Pure ***
    62 
    63 * class_package.ML offers a combination of axclasses and locales to
    64 achieve Haskell-like type classes in Isabelle. See
    65 HOL/ex/Classpackage.thy for examples.
    66 
    67 * Yet another code generator framework allows to generate executable
    68 code for ML and Haskell (including "class"es). A short usage sketch:
    69 
    70     internal compilation:
    71         code_gen <list of constants (term syntax)> (SML #)
    72     writing SML code to a file:
    73         code_gen <list of constants (term syntax)> (SML <filename>)
    74     writing Haskell code to a bunch of files:
    75         code_gen <list of constants (term syntax)> (Haskell <filename>)
    76 
    77 Reasonable default setup of framework in HOL/Main.
    78 
    79 See HOL/ex/Code*.thy for examples.
    80 
    81 Theorem attributs for selecting and transforming function equations theorems:
    82 
    83     [code fun]:       select a theorem as function equation for a specific constant
    84     [code nofun]:     deselect a theorem as function equation for a specific constant
    85     [code inline]:    select an equation theorem for unfolding (inlining) in place
    86     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    87 
    88 User-defined serializations (target in {SML, Haskell}):
    89 
    90     code_const <and-list of constants (term syntax)>
    91       {(target) <and-list of const target syntax>}+
    92 
    93     code_type <and-list of type constructors>
    94       {(target) <and-list of type target syntax>}+
    95 
    96     code_instance <and-list of instances>
    97       {(target)}+
    98         where instance ::= <type constructor> :: <class>
    99 
   100     code_class <and_list of classes>
   101       {(target) <and-list of class target syntax>}+
   102         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   103 
   104 For code_instance and code_class, target SML is silently ignored.
   105 
   106 See HOL theories and HOL/ex/Code*.thy for usage examples.  Doc/Isar/Advanced/Codegen/
   107 provides a tutorial.
   108 
   109 * Command 'no_translations' removes translation rules from theory
   110 syntax.
   111 
   112 * Overloaded definitions are now actually checked for acyclic
   113 dependencies.  The overloading scheme is slightly more general than
   114 that of Haskell98, although Isabelle does not demand an exact
   115 correspondence to type class and instance declarations.
   116 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   117 exotic versions of overloading -- at the discretion of the user!
   118 
   119 Polymorphic constants are represented via type arguments, i.e. the
   120 instantiation that matches an instance against the most general
   121 declaration given in the signature.  For example, with the declaration
   122 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   123 as c(nat).  Overloading is essentially simultaneous structural
   124 recursion over such type arguments.  Incomplete specification patterns
   125 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   126 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   127 Command 'print_theory' outputs the normalized system of recursive
   128 equations, see section "definitions".
   129 
   130 * Isar: improper proof element 'guess' is like 'obtain', but derives
   131 the obtained context from the course of reasoning!  For example:
   132 
   133   assume "EX x y. A x & B y"   -- "any previous fact"
   134   then guess x and y by clarify
   135 
   136 This technique is potentially adventurous, depending on the facts and
   137 proof tools being involved here.
   138 
   139 * Isar: known facts from the proof context may be specified as literal
   140 propositions, using ASCII back-quote syntax.  This works wherever
   141 named facts used to be allowed so far, in proof commands, proof
   142 methods, attributes etc.  Literal facts are retrieved from the context
   143 according to unification of type and term parameters.  For example,
   144 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   145 theorems in the current context, then these are valid literal facts:
   146 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   147 
   148 There is also a proof method "fact" which does the same composition
   149 for explicit goal states, e.g. the following proof texts coincide with
   150 certain special cases of literal facts:
   151 
   152   have "A" by fact                 ==  note `A`
   153   have "A ==> B" by fact           ==  note `A ==> B`
   154   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   155   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   156 
   157 * Isar: ":" (colon) is no longer a symbolic identifier character in
   158 outer syntax.  Thus symbolic identifiers may be used without
   159 additional white space in declarations like this: ``assume *: A''.
   160 
   161 * Isar: 'print_facts' prints all local facts of the current context,
   162 both named and unnamed ones.
   163 
   164 * Isar: 'def' now admits simultaneous definitions, e.g.:
   165 
   166   def x == "t" and y == "u"
   167 
   168 * Isar: added command 'unfolding', which is structurally similar to
   169 'using', but affects both the goal state and facts by unfolding given
   170 rewrite rules.  Thus many occurrences of the 'unfold' method or
   171 'unfolded' attribute may be replaced by first-class proof text.
   172 
   173 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   174 and command 'unfolding' now all support object-level equalities
   175 (potentially conditional).  The underlying notion of rewrite rule is
   176 analogous to the 'rule_format' attribute, but *not* that of the
   177 Simplifier (which is usually more generous).
   178 
   179 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   180 method expression within a sandbox consisting of the first N
   181 sub-goals, which need to exist.  For example, ``simp_all [3]''
   182 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   183 simplifies all new goals that emerge from applying rule foo to the
   184 originally first one.
   185 
   186 * Isar: schematic goals are no longer restricted to higher-order
   187 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   188 expected.
   189 
   190 * Isar: the conclusion of a long theorem statement is now either
   191 'shows' (a simultaneous conjunction, as before), or 'obtains'
   192 (essentially a disjunction of cases with local parameters and
   193 assumptions).  The latter allows to express general elimination rules
   194 adequately; in this notation common elimination rules look like this:
   195 
   196   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   197     assumes "EX x. P x"
   198     obtains x where "P x"
   199 
   200   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   201     assumes "A & B"
   202     obtains A and B
   203 
   204   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   205     assumes "A | B"
   206     obtains
   207       A
   208     | B
   209 
   210 The subsequent classical rules even refer to the formal "thesis"
   211 explicitly:
   212 
   213   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   214     obtains "~ thesis"
   215 
   216   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   217     obtains "thesis ==> something"
   218 
   219 The actual proof of an 'obtains' statement is analogous to that of the
   220 Isar proof element 'obtain', only that there may be several cases.
   221 Optional case names may be specified in parentheses; these will be
   222 available both in the present proof and as annotations in the
   223 resulting rule, for later use with the 'cases' method (cf. attribute
   224 case_names).
   225 
   226 * Isar: the assumptions of a long theorem statement are available as
   227 "assms" fact in the proof context.  This is more appropriate than the
   228 (historical) "prems", which refers to all assumptions of the current
   229 context, including those from the target locale, proof body etc.
   230 
   231 * Isar: 'print_statement' prints theorems from the current theory or
   232 proof context in long statement form, according to the syntax of a
   233 top-level lemma.
   234 
   235 * Isar: 'obtain' takes an optional case name for the local context
   236 introduction rule (default "that").
   237 
   238 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   239 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   240 to occur.
   241 
   242 * Pure: syntax "CONST name" produces a fully internalized constant
   243 according to the current context.  This is particularly useful for
   244 syntax translations that should refer to internal constant
   245 representations independently of name spaces.
   246 
   247 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   248 instead of "FOO ". This allows multiple binder declarations to coexist
   249 in the same context.  INCOMPATIBILITY.
   250 
   251 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   252 primitive that also works in a locale context (both for constants and
   253 fixed variables).  Type declaration and internal syntactic
   254 representation of given constants retrieved from the context.
   255 
   256 * Isar/locales: new derived specification elements 'axiomatization',
   257 'definition', 'abbreviation', which support type-inference, admit
   258 object-level specifications (equality, equivalence).  See also the
   259 isar-ref manual.  Examples:
   260 
   261   axiomatization
   262     eq  (infix "===" 50) where
   263     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   264 
   265   definition "f x y = x + y + 1"
   266   definition g where "g x = f x x"
   267 
   268   abbreviation
   269     neq  (infix "=!=" 50) where
   270     "x =!= y == ~ (x === y)"
   271 
   272 These specifications may be also used in a locale context.  Then the
   273 constants being introduced depend on certain fixed parameters, and the
   274 constant name is qualified by the locale base name.  An internal
   275 abbreviation takes care for convenient input and output, making the
   276 parameters implicit and using the original short name.  See also
   277 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   278 entities from a monomorphic theory.
   279 
   280 Presently, abbreviations are only available 'in' a target locale, but
   281 not inherited by general import expressions.  Also note that
   282 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   283 'translations' in common applications.
   284 
   285 Concrete syntax is attached to specified constants in internal form,
   286 independently of name spaces.  The parse tree representation is
   287 slightly different -- use 'notation' instead of raw 'syntax', and
   288 'translations' with explicit "CONST" markup to accommodate this.
   289 
   290 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   291 the current context.  Print mode "no_abbrevs" prevents inversion of
   292 abbreviations on output.
   293 
   294 * Isar/locales: improved parameter handling:
   295 - use of locales "var" and "struct" no longer necessary;
   296 - parameter renamings are no longer required to be injective.
   297   This enables, for example, to define a locale for endomorphisms thus:
   298   locale endom = homom mult mult h.
   299 
   300 * Isar/locales: changed the way locales with predicates are defined.
   301 Instead of accumulating the specification, the imported expression is
   302 now an interpretation.
   303 INCOMPATIBILITY: different normal form of locale expressions.
   304 In particular, in interpretations of locales with predicates,
   305 goals repesenting already interpreted fragments are not removed
   306 automatically.  Use methods `intro_locales' and `unfold_locales'; see below.
   307 
   308 * Isar/locales: new methods `intro_locales' and `unfold_locales' provide
   309 backward reasoning on locales predicates.  The methods are aware of
   310 interpretations and discharge corresponding goals.  `intro_locales' is
   311 less aggressive then `unfold_locales' and does not unfold predicates to
   312 assumptions.
   313 
   314 * Isar/locales: the order in which locale fragments are accumulated
   315 has changed.  This enables to override declarations from fragments
   316 due to interpretations -- for example, unwanted simp rules.
   317 
   318 * Provers/induct: improved internal context management to support
   319 local fixes and defines on-the-fly.  Thus explicit meta-level
   320 connectives !! and ==> are rarely required anymore in inductive goals
   321 (using object-logic connectives for this purpose has been long
   322 obsolete anyway).  The subsequent proof patterns illustrate advanced
   323 techniques of natural induction; general datatypes and inductive sets
   324 work analogously (see also src/HOL/Lambda for realistic examples).
   325 
   326 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   327 parameters:
   328 
   329   lemma
   330     fixes n :: nat and x :: 'a
   331     assumes a: "A n x"
   332     shows "P n x"
   333     using a                     -- {* make induct insert fact a *}
   334   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   335     case 0
   336     show ?case sorry
   337   next
   338     case (Suc n)
   339     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   340     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   341     show ?case sorry
   342   qed
   343 
   344 (2) This is how to perform induction over ``expressions of a certain
   345 form'', using a locally defined inductive parameter n == "a x"
   346 together with strengthening (the latter is usually required to get
   347 sufficiently flexible induction hypotheses):
   348 
   349   lemma
   350     fixes a :: "'a => nat"
   351     assumes a: "A (a x)"
   352     shows "P (a x)"
   353     using a
   354   proof (induct n == "a x" arbitrary: x)
   355     ...
   356 
   357 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   358 particular technique.
   359 
   360 (3) This is how to perform existential reasoning ('obtains' or
   361 'obtain') by induction, while avoiding explicit object-logic
   362 encodings:
   363 
   364   lemma
   365     fixes n :: nat
   366     obtains x :: 'a where "P n x" and "Q n x"
   367   proof (induct n arbitrary: thesis)
   368     case 0
   369     obtain x where "P 0 x" and "Q 0 x" sorry
   370     then show thesis by (rule 0)
   371   next
   372     case (Suc n)
   373     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   374     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   375     then show thesis by (rule Suc.prems)
   376   qed
   377 
   378 Here the 'arbitrary: thesis' specification essentially modifies the
   379 scope of the formal thesis parameter, in order to the get the whole
   380 existence statement through the induction as expected.
   381 
   382 * Provers/induct: mutual induction rules are now specified as a list
   383 of rule sharing the same induction cases.  HOL packages usually
   384 provide foo_bar.inducts for mutually defined items foo and bar
   385 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   386 specify mutual induction rules differently, i.e. like this:
   387 
   388   (induct rule: foo_bar.inducts)
   389   (induct set: foo bar)
   390   (induct type: foo bar)
   391 
   392 The ML function ProjectRule.projections turns old-style rules into the
   393 new format.
   394 
   395 * Provers/induct: improved handling of simultaneous goals.  Instead of
   396 introducing object-level conjunction, the statement is now split into
   397 several conclusions, while the corresponding symbolic cases are
   398 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   399 explicitly.  For example:
   400 
   401   lemma
   402     fixes n :: nat
   403     shows "P n" and "Q n"
   404   proof (induct n)
   405     case 0 case 1
   406     show "P 0" sorry
   407   next
   408     case 0 case 2
   409     show "Q 0" sorry
   410   next
   411     case (Suc n) case 1
   412     note `P n` and `Q n`
   413     show "P (Suc n)" sorry
   414   next
   415     case (Suc n) case 2
   416     note `P n` and `Q n`
   417     show "Q (Suc n)" sorry
   418   qed
   419 
   420 The split into subcases may be deferred as follows -- this is
   421 particularly relevant for goal statements with local premises.
   422 
   423   lemma
   424     fixes n :: nat
   425     shows "A n ==> P n" and "B n ==> Q n"
   426   proof (induct n)
   427     case 0
   428     {
   429       case 1
   430       note `A 0`
   431       show "P 0" sorry
   432     next
   433       case 2
   434       note `B 0`
   435       show "Q 0" sorry
   436     }
   437   next
   438     case (Suc n)
   439     note `A n ==> P n` and `B n ==> Q n`
   440     {
   441       case 1
   442       note `A (Suc n)`
   443       show "P (Suc n)" sorry
   444     next
   445       case 2
   446       note `B (Suc n)`
   447       show "Q (Suc n)" sorry
   448     }
   449   qed
   450 
   451 If simultaneous goals are to be used with mutual rules, the statement
   452 needs to be structured carefully as a two-level conjunction, using
   453 lists of propositions separated by 'and':
   454 
   455   lemma
   456     shows "a : A ==> P1 a"
   457           "a : A ==> P2 a"
   458       and "b : B ==> Q1 b"
   459           "b : B ==> Q2 b"
   460           "b : B ==> Q3 b"
   461   proof (induct set: A B)
   462 
   463 * Provers/induct: support coinduction as well.  See
   464 src/HOL/Library/Coinductive_List.thy for various examples.
   465 
   466 * Attribute "symmetric" produces result with standardized schematic
   467 variables (index 0).  Potential INCOMPATIBILITY.
   468 
   469 * Simplifier: by default the simplifier trace only shows top level rewrites
   470 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   471 less danger of being flooded by the trace. The trace indicates where parts
   472 have been suppressed.
   473   
   474 * Provers/classical: removed obsolete classical version of elim_format
   475 attribute; classical elim/dest rules are now treated uniformly when
   476 manipulating the claset.
   477 
   478 * Provers/classical: stricter checks to ensure that supplied intro,
   479 dest and elim rules are well-formed; dest and elim rules must have at
   480 least one premise.
   481 
   482 * Provers/classical: attributes dest/elim/intro take an optional
   483 weight argument for the rule (just as the Pure versions).  Weights are
   484 ignored by automated tools, but determine the search order of single
   485 rule steps.
   486 
   487 * Syntax: input syntax now supports dummy variable binding "%_. b",
   488 where the body does not mention the bound variable.  Note that dummy
   489 patterns implicitly depend on their context of bounds, which makes
   490 "{_. _}" match any set comprehension as expected.  Potential
   491 INCOMPATIBILITY -- parse translations need to cope with syntactic
   492 constant "_idtdummy" in the binding position.
   493 
   494 * Syntax: removed obsolete syntactic constant "_K" and its associated
   495 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   496 for example "A -> B" => "Pi A (%_. B)".
   497 
   498 * Pure: 'class_deps' command visualizes the subclass relation, using
   499 the graph browser tool.
   500 
   501 * Pure: 'print_theory' now suppresses entities with internal name
   502 (trailing "_") by default; use '!' option for full details.
   503 
   504 
   505 *** HOL ***
   506 
   507 * New syntactic class "size"; overloaded constant "size" now
   508 has type "'a::size ==> bool"
   509 
   510 * Constants "Divides.op div", "Divides.op mod" and "Divides.op dvd" no named
   511   "Divides.div", "Divides.mod" and "Divides.dvd"
   512   INCOMPATIBILITY for ML code directly refering to constant names.
   513 
   514 * Replaced "auto_term" by the conceptually simpler method "relation",
   515 which just applies the instantiated termination rule with no further
   516 simplifications.
   517 INCOMPATIBILITY: 
   518 Replace 
   519         termination by (auto_term "MYREL")
   520 with 
   521         termination by (relation "MYREL") auto
   522 
   523 * Automated termination proofs "by lexicographic_order" are now
   524 included in the abbreviated function command "fun". No explicit
   525 "termination" command is necessary anymore.
   526 INCOMPATIBILITY: If a "fun"-definition cannot be proved terminating by
   527 a lexicographic size order, then the command fails. Use the expanded
   528 version "function" for these cases.
   529 
   530 * New method "lexicographic_order" automatically synthesizes
   531 termination relations as lexicographic combinations of size measures. 
   532 Usage for (function package) termination proofs:
   533 
   534 termination 
   535 by lexicographic_order
   536 
   537 * Records: generalised field-update to take a function on the field 
   538 rather than the new value: r(|A := x|) is translated to A_update (K x) r
   539 The K-combinator that is internally used is called K_record.
   540 INCOMPATIBILITY: Usage of the plain update functions has to be
   541 adapted.
   542  
   543 * axclass "semiring_0" now contains annihilation axioms 
   544 ("x * 0 = 0","0 * x = 0"), which are required for a semiring. Richer 
   545 structures do not inherit from semiring_0 anymore, because this property 
   546 is a theorem there, not an axiom.
   547 INCOMPATIBILITY: In instances of semiring_0, there is more to prove, but 
   548 this is mostly trivial.
   549 
   550 * axclass "recpower" was generalized to arbitrary monoids, not just 
   551 commutative semirings.
   552 INCOMPATIBILITY: If you use recpower and need commutativity or a semiring
   553 property, add the corresponding classes.
   554 
   555 * Locale Lattic_Locales.partial_order changed (to achieve consistency with
   556 axclass order):
   557 - moved to Orderings.partial_order
   558 - additional parameter ``less''
   559 INCOMPATIBILITY.
   560 
   561 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   562 INCOMPATIBILITY: translations containing list_all2 may go wrong. On Isar
   563 level, use abbreviations instead.
   564 
   565 * Constant "List.op mem" in List.thy now has proper name: "List.memberl"
   566 INCOMPATIBILITY: rarely occuring name references (e.g. ``List.op mem.simps'')
   567 require renaming (e.g. ``List.memberl.simps'').
   568 
   569 * Renamed constants in HOL.thy:
   570     0      ~> HOL.zero
   571     1      ~> HOL.one
   572 INCOMPATIBILITY: ML code directly refering to constant names may need adaption
   573 This in general only affects hand-written proof tactics, simprocs and so on.
   574 
   575 * New theory Code_Generator providing class 'eq',
   576 allowing for code generation with polymorphic equality.
   577 
   578 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has been
   579 abandoned in favour of plain 'int'. INCOMPATIBILITY -- Significant changes
   580 for setting up numeral syntax for types:
   581 
   582   - new constants Numeral.pred and Numeral.succ instead
   583       of former Numeral.bin_pred and Numeral.bin_succ.
   584   - Use integer operations instead of bin_add, bin_mult and so on.
   585   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   586   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   587 
   588 See HOL/Integ/IntArith.thy for an example setup.
   589 
   590 * New top level command 'normal_form' computes the normal form of a term
   591 that may contain free variables. For example 'normal_form "rev[a,b,c]"'
   592 prints '[b,c,a]'. This command is suitable for heavy-duty computations
   593 because the functions are compiled to ML first.
   594 INCOMPATIBILITY: new keywords 'normal_form' must quoted when used as
   595 an identifier.
   596 
   597 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   598 25 like -->); output depends on the "iff" print_mode, the default is
   599 "A = B" (with priority 50).
   600 
   601 * Renamed constants in HOL.thy and Orderings.thy:
   602     op +   ~> HOL.plus
   603     op -   ~> HOL.minus
   604     uminus ~> HOL.uminus
   605     op *   ~> HOL.times
   606     op <   ~> Orderings.less
   607     op <=  ~> Orderings.less_eq
   608 
   609 Adaptions may be required in the following cases:
   610 
   611 a) User-defined constants using any of the names "plus", "minus", "times",
   612 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   613 may go wrong.
   614 INCOMPATIBILITY: use more specific names.
   615 
   616 b) Variables named "plus", "minus", "times", "less", "less_eq"
   617 INCOMPATIBILITY: use more specific names.
   618 
   619 c) Permutative equations (e.g. "a + b = b + a")
   620 Since the change of names also changes the order of terms, permutative
   621 rewrite rules may get applied in a different order. Experience shows that
   622 this is rarely the case (only two adaptions in the whole Isabelle
   623 distribution).
   624 INCOMPATIBILITY: rewrite proofs
   625 
   626 d) ML code directly refering to constant names
   627 This in general only affects hand-written proof tactics, simprocs and so on.
   628 INCOMPATIBILITY: grep your sourcecode and replace names.
   629 
   630 * Relations less (<) and less_eq (<=) are also available on type bool.
   631 Modified syntax to disallow nesting without explicit parentheses,
   632 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   633 
   634 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   635 
   636 * Relation composition operator "op O" now has precedence 75 and binds
   637 stronger than union and intersection. INCOMPATIBILITY.
   638 
   639 * The old set interval syntax "{m..n(}" (and relatives) has been removed.
   640   Use "{m..<n}" (and relatives) instead.
   641 
   642 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   643 "t = s" to False (by simproc "neq_simproc").  For backward
   644 compatibility this can be disabled by ML "reset use_neq_simproc".
   645 
   646 * "m dvd n" where m and n are numbers is evaluated to True/False by simp.
   647 
   648 * Theorem Cons_eq_map_conv no longer has attribute `simp'.
   649 
   650 * Theorem setsum_mult renamed to setsum_right_distrib.
   651 
   652 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   653 'rule' method.
   654 
   655 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   656 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   657 "=" on type bool) are handled, variable names of the form "lit_<n>"
   658 are no longer reserved, significant speedup.
   659 
   660 * Tactics 'sat' and 'satx' can now replay MiniSat proof traces.  zChaff is
   661 still supported as well.
   662 
   663 * inductive and datatype: provide projections of mutual rules, bundled
   664 as foo_bar.inducts;
   665 
   666 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to Library.
   667 
   668 * Library: moved theory Accessible_Part to main HOL.
   669 
   670 * Library: added theory Coinductive_List of potentially infinite lists
   671 as greatest fixed-point.
   672 
   673 * Library: added theory AssocList which implements (finite) maps as
   674 association lists.
   675 
   676 * New proof method "evaluation" for efficiently solving a goal (i.e. a
   677 boolean expression) by compiling it to ML. The goal is "proved" (via
   678 the oracle "Evaluation") if it evaluates to True.
   679 
   680 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   681 also when invoked by the simplifier.  This results in the simplifier
   682 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   683 fast_arith_split_limit to 0 to obtain the old behavior.
   684 
   685 * Support for hex (0x20) and binary (0b1001) numerals. 
   686 
   687 * New method: reify eqs (t), where eqs are equations for an
   688 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   689 parameter, computes a term s::'b and a list xs::'a list and proves the
   690 theorem I xs s = t. This is also known as reification or quoting. The
   691 resulting theorem is applied to the subgoal to substitute t with I xs
   692 s.  If t is omitted, the subgoal itself is reified.
   693 
   694 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   695 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   696 where f is supposed to be a computable function (in the sense of code
   697 generattion). The method uses reify to compute s and xs as above then
   698 applies corr_thm and uses normalization by evaluation to "prove" f s =
   699 r and finally gets the theorem t = r, which is again applied to the
   700 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   701 
   702 * Reflection: Automatic refification now handels binding, an example
   703 is available in HOL/ex/ReflectionEx.thy
   704 
   705 
   706 *** HOL-Algebra ***
   707 
   708 * Formalisation of ideals and the quotient construction over rings.
   709 
   710 * Order and lattice theory no longer based on records.
   711 INCOMPATIBILITY.
   712 
   713 * Renamed lemmas least_carrier -> least_closed and
   714 greatest_carrier -> greatest_closed.  INCOMPATIBILITY.
   715 
   716 * Method algebra is now set up via an attribute.  For examples see
   717 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   718 of algebraic structures.
   719 
   720 * Renamed `CRing.thy' to `Ring.thy'.  INCOMPATIBILITY.
   721 
   722 
   723 *** HOL-Complex ***
   724 
   725 * Theory Real: new method ferrack implements quantifier elimination
   726 for linear arithmetic over the reals. The quantifier elimination
   727 feature is used only for decision, for compatibility with arith. This
   728 means a goal is either solved or left unchanged, no simplification.
   729 
   730 * Real: New axiomatic classes formalize real normed vector spaces and
   731 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   732 and norm :: 'a => real.
   733 
   734 * Real: New constant of_real :: real => 'a::real_algebra_1 injects from
   735 reals into other types. The overloaded constant Reals :: 'a set is now
   736 defined as range of_real; potential INCOMPATIBILITY.
   737 
   738 * Hyperreal: Several constants that previously worked only for the reals
   739 have been generalized, so they now work over arbitrary vector spaces. Type
   740 annotations may need to be added in some cases; potential INCOMPATIBILITY.
   741 
   742   Infinitesimal  :: ('a::real_normed_vector) star set"
   743   HFinite        :: ('a::real_normed_vector) star set"
   744   HInfinite      :: ('a::real_normed_vector) star set"
   745   approx         :: ('a::real_normed_vector) star => 'a star => bool
   746   monad          :: ('a::real_normed_vector) star => 'a star set
   747   galaxy         :: ('a::real_normed_vector) star => 'a star set
   748   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   749   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   750   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   751   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   752   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   753   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   754   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   755 
   756 * Complex: Some complex-specific constants are now abbreviations for
   757 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod = hnorm.
   758 Other constants have been entirely removed in favor of the polymorphic
   759 versions (INCOMPATIBILITY):
   760 
   761   approx        <-- capprox
   762   HFinite       <-- CFinite
   763   HInfinite     <-- CInfinite
   764   Infinitesimal <-- CInfinitesimal
   765   monad         <-- cmonad
   766   galaxy        <-- cgalaxy
   767   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   768   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   769   (ns)deriv     <-- (ns)cderiv
   770 
   771 
   772 *** ML ***
   773 
   774 * Pure/Isar/args.ML & Pure/Isar/method.ML
   775 
   776 switched argument order in *.syntax lifters.
   777 
   778 * Pure/table:
   779 
   780 Function `...tab.foldl` removed.
   781 INCOMPATIBILITY: use `...tabfold` instead
   782 
   783 * Pure/library:
   784 
   785 `gen_rem(s)` abandoned in favour of `remove` / `subtract`.
   786 INCOMPATIBILITY:
   787 rewrite "gen_rem eq (xs, x)" to "remove (eq o swap) x xs"
   788 rewrite "gen_rems eq (xs, ys)" to "subtract (eq o swap) ys xs"
   789 drop "swap" if "eq" is symmetric.
   790 
   791 * Pure/library:
   792 
   793 infixes `ins` `ins_string` `ins_int` have been abandoned in favour of `insert`.
   794 INCOMPATIBILITY: rewrite "x ins(_...) xs" to "insert (op =) x xs"
   795 
   796 * Pure/General/susp.ML:
   797 
   798 New module for delayed evaluations.
   799 
   800 * Pure/library:
   801 
   802 Semantically identical functions "equal_list" and "eq_list" have been
   803 unified to "eq_list".
   804 
   805 * Pure/library:
   806 
   807   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   808   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   809 
   810 The semantics of "burrow" is: "take a function with *simulatanously*
   811 transforms a list of value, and apply it *simulatanously* to a list of
   812 list of values of the appropriate type". Confer this with "map" which
   813 would *not* apply its argument function simulatanously but in
   814 sequence. "fold_burrow" has an additional context.
   815 
   816 Both actually avoid the usage of "unflat" since they hide away
   817 "unflat" from the user.
   818 
   819 * Pure/library: functions map2 and fold2 with curried syntax for
   820 simultanous mapping and folding:
   821 
   822     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   823     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   824 
   825 * Pure/library: indexed lists - some functions in the Isabelle library
   826 treating lists over 'a as finite mappings from [0...n] to 'a have been
   827 given more convenient names and signatures reminiscent of similar
   828 functions for alists, tables, etc:
   829 
   830   val nth: 'a list -> int -> 'a 
   831   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   832   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   833 
   834 Note that fold_index starts counting at index 0, not 1 like foldln
   835 used to.
   836 
   837 * Pure/library: general ``divide_and_conquer'' combinator on lists.
   838 
   839 * Pure/General/name_mangler.ML provides a functor for generic name
   840 mangling (bijective mapping from expression values to strings).
   841 
   842 * Pure/General/rat.ML implements rational numbers.
   843 
   844 * Pure/General/table.ML: the join operations now works via exceptions
   845 DUP/SAME instead of type option.  This is simpler in simple cases, and
   846 admits slightly more efficient complex applications.
   847 
   848 * Pure: datatype Context.generic joins theory/Proof.context and
   849 provides some facilities for code that works in either kind of
   850 context, notably GenericDataFun for uniform theory and proof data.
   851 
   852 * Pure: 'advanced' translation functions (parse_translation etc.) now
   853 use Context.generic instead of just theory.
   854 
   855 * Pure: simplified internal attribute type, which is now always
   856 Context.generic * thm -> Context.generic * thm.  Global (theory)
   857 vs. local (Proof.context) attributes have been discontinued, while
   858 minimizing code duplication.  Thm.rule_attribute and
   859 Thm.declaration_attribute build canonical attributes; see also
   860 structure Context for further operations on Context.generic, notably
   861 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   862 declarations and definitions.
   863 
   864 * Pure/kernel: consts certification ignores sort constraints given in
   865 signature declarations.  (This information is not relevant to the
   866 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE.
   867 
   868 * Pure: axiomatic type classes are now purely definitional, with
   869 explicit proofs of class axioms and super class relations performed
   870 internally.  See Pure/axclass.ML for the main internal interfaces --
   871 notably AxClass.define_class supercedes AxClass.add_axclass, and
   872 AxClass.axiomatize_class/classrel/arity supercede
   873 Sign.add_classes/classrel/arities.
   874 
   875 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   876 global/local versions on theory vs. Proof.context have been
   877 discontinued; Attrib.syntax and Method.syntax have been adapted
   878 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   879 attributes, methods, etc.
   880 
   881 * Pure: several functions of signature "... -> theory -> theory * ..."
   882 have been reoriented to "... -> theory -> ... * theory" in order to
   883 allow natural usage in combination with the ||>, ||>>, |-> and
   884 fold_map combinators.
   885 
   886 * Pure: official theorem names (closed derivations) and additional
   887 comments (tags) are now strictly separate.  Name hints -- which are
   888 maintained as tags -- may be attached any time without affecting the
   889 derivation.
   890 
   891 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   892 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   893 achieve the old behaviour.
   894 
   895 * Pure: the "Goal" constant is now called "prop", supporting a
   896 slightly more general idea of ``protecting'' meta-level rule
   897 statements.
   898 
   899 * Pure: Logic.(un)varify only works in a global context, which is now
   900 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   901 Logic.legacy_(un)varify as temporary workaround.
   902 
   903 * Pure: structure Name provides scalable operations for generating
   904 internal variable names, notably Name.variants etc.  This replaces
   905 some popular functions from term.ML:
   906 
   907   Term.variant		->  Name.variant
   908   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   909   Term.invent_names	->  Name.invent_list
   910 
   911 Note that low-level renaming rarely occurs in new code -- operations
   912 from structure Variable are used instead (see below).
   913 
   914 * Pure: structure Variable provides fundamental operations for proper
   915 treatment of fixed/schematic variables in a context.  For example,
   916 Variable.import introduces fixes for schematics of given facts and
   917 Variable.export reverses the effect (up to renaming) -- this replaces
   918 various freeze_thaw operations.
   919 
   920 * Pure: structure Goal provides simple interfaces for
   921 init/conclude/finish and tactical prove operations (replacing former
   922 Tactic.prove).  Goal.prove is the canonical way to prove results
   923 within a given context; Goal.prove_global is a degraded version for
   924 theory level goals, including a global Drule.standard.  Note that
   925 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   926 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   927 in a locale context).
   928 
   929 * Isar: simplified treatment of user-level errors, using exception
   930 ERROR of string uniformly.  Function error now merely raises ERROR,
   931 without any side effect on output channels.  The Isar toplevel takes
   932 care of proper display of ERROR exceptions.  ML code may use plain
   933 handle/can/try; cat_error may be used to concatenate errors like this:
   934 
   935   ... handle ERROR msg => cat_error msg "..."
   936 
   937 Toplevel ML code (run directly or through the Isar toplevel) may be
   938 embedded into the Isar toplevel with exception display/debug like
   939 this:
   940 
   941   Isar.toplevel (fn () => ...)
   942 
   943 INCOMPATIBILITY, removed special transform_error facilities, removed
   944 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   945 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   946 -- use plain ERROR instead.
   947 
   948 * Isar: theory setup now has type (theory -> theory), instead of a
   949 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   950 
   951 * Isar: installed ML toplevel pretty printer for type Proof.context,
   952 subject to ProofContext.debug/verbose flags.
   953 
   954 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   955 theory before entering a proof state.  Transactions now always see a
   956 quasi-functional intermediate checkpoint, both in interactive and
   957 batch mode.
   958 
   959 * Simplifier: the simpset of a running simplification process now
   960 contains a proof context (cf. Simplifier.the_context), which is the
   961 very context that the initial simpset has been retrieved from (by
   962 simpset_of/local_simpset_of).  Consequently, all plug-in components
   963 (solver, looper etc.) may depend on arbitrary proof data.
   964 
   965 * Simplifier.inherit_context inherits the proof context (plus the
   966 local bounds) of the current simplification process; any simproc
   967 etc. that calls the Simplifier recursively should do this!  Removed
   968 former Simplifier.inherit_bounds, which is already included here --
   969 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   970 specify an explicit context using Simplifier.context/theory_context.
   971 
   972 * Simplifier/Classical Reasoner: more abstract interfaces
   973 change_simpset/claset for modifying the simpset/claset reference of a
   974 theory; raw versions simpset/claset_ref etc. have been discontinued --
   975 INCOMPATIBILITY.
   976 
   977 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   978 "Trueprop" etc.
   979 
   980 
   981 *** System ***
   982 
   983 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   984 locations -- now includes the Isabelle version identifier as well.
   985 This simplifies use of multiple Isabelle installations.
   986 
   987 * isabelle-process: option -S (secure mode) disables some critical
   988 operations, notably runtime compilation and evaluation of ML source
   989 code.
   990 
   991 
   992 New in Isabelle2005 (October 2005)
   993 ----------------------------------
   994 
   995 *** General ***
   996 
   997 * Theory headers: the new header syntax for Isar theories is
   998 
   999   theory <name>
  1000   imports <theory1> ... <theoryN>
  1001   uses <file1> ... <fileM>
  1002   begin
  1003 
  1004 where the 'uses' part is optional.  The previous syntax
  1005 
  1006   theory <name> = <theory1> + ... + <theoryN>:
  1007 
  1008 will disappear in the next release.  Use isatool fixheaders to convert
  1009 existing theory files.  Note that there is no change in ancient
  1010 non-Isar theories now, but these will disappear soon.
  1011 
  1012 * Theory loader: parent theories can now also be referred to via
  1013 relative and absolute paths.
  1014 
  1015 * Command 'find_theorems' searches for a list of criteria instead of a
  1016 list of constants. Known criteria are: intro, elim, dest, name:string,
  1017 simp:term, and any term. Criteria can be preceded by '-' to select
  1018 theorems that do not match. Intro, elim, dest select theorems that
  1019 match the current goal, name:s selects theorems whose fully qualified
  1020 name contain s, and simp:term selects all simplification rules whose
  1021 lhs match term.  Any other term is interpreted as pattern and selects
  1022 all theorems matching the pattern. Available in ProofGeneral under
  1023 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1024 
  1025   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1026 
  1027 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1028 matching the current goal as introduction rule and not having "HOL."
  1029 in their name (i.e. not being defined in theory HOL).
  1030 
  1031 * Command 'thms_containing' has been discontinued in favour of
  1032 'find_theorems'; INCOMPATIBILITY.
  1033 
  1034 * Communication with Proof General is now 8bit clean, which means that
  1035 Unicode text in UTF-8 encoding may be used within theory texts (both
  1036 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1037 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1038 
  1039   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1040   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1041 
  1042 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1043 Classical Reasoner.  Typical big applications run around 2 times
  1044 faster.
  1045 
  1046 
  1047 *** Document preparation ***
  1048 
  1049 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1050 of raw sources.  Only those symbols that do not require additional
  1051 LaTeX packages (depending on comments in isabellesym.sty) are
  1052 displayed properly, everything else is left verbatim.  isatool display
  1053 and isatool print are used as front ends (these are subject to the
  1054 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1055 
  1056 * Command tags control specific markup of certain regions of text,
  1057 notably folding and hiding.  Predefined tags include "theory" (for
  1058 theory begin and end), "proof" for proof commands, and "ML" for
  1059 commands involving ML code; the additional tags "visible" and
  1060 "invisible" are unused by default.  Users may give explicit tag
  1061 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1062 interpretation of tags is determined by the LaTeX job during document
  1063 preparation: see option -V of isatool usedir, or options -n and -t of
  1064 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1065 \isadroptag.
  1066 
  1067 Several document versions may be produced at the same time via isatool
  1068 usedir (the generated index.html will link all of them).  Typical
  1069 specifications include ''-V document=theory,proof,ML'' to present
  1070 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1071 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1072 these parts without any formal replacement text.  The Isabelle site
  1073 default settings produce ''document'' and ''outline'' versions as
  1074 specified above.
  1075 
  1076 * Several new antiquotations:
  1077 
  1078   @{term_type term} prints a term with its type annotated;
  1079 
  1080   @{typeof term} prints the type of a term;
  1081 
  1082   @{const const} is the same as @{term const}, but checks that the
  1083   argument is a known logical constant;
  1084 
  1085   @{term_style style term} and @{thm_style style thm} print a term or
  1086   theorem applying a "style" to it
  1087 
  1088   @{ML text}
  1089 
  1090 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1091 definitions, equations, inequations etc., 'concl' printing only the
  1092 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1093 to print the specified premise.  TermStyle.add_style provides an ML
  1094 interface for introducing further styles.  See also the "LaTeX Sugar"
  1095 document practical applications.  The ML antiquotation prints
  1096 type-checked ML expressions verbatim.
  1097 
  1098 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1099 and 'text' support optional locale specification '(in loc)', which
  1100 specifies the default context for interpreting antiquotations.  For
  1101 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1102 
  1103 * Option 'locale=NAME' of antiquotations specifies an alternative
  1104 context interpreting the subsequent argument.  For example: @{thm
  1105 [locale=lattice] inf_assoc}.
  1106 
  1107 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1108 a proof context.
  1109 
  1110 * Proper output of antiquotations for theory commands involving a
  1111 proof context (such as 'locale' or 'theorem (in loc) ...').
  1112 
  1113 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1114 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1115 
  1116 * isatool usedir: new option -C (default true) controls whether option
  1117 -D should include a copy of the original document directory; -C false
  1118 prevents unwanted effects such as copying of administrative CVS data.
  1119 
  1120 
  1121 *** Pure ***
  1122 
  1123 * Considerably improved version of 'constdefs' command.  Now performs
  1124 automatic type-inference of declared constants; additional support for
  1125 local structure declarations (cf. locales and HOL records), see also
  1126 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1127 sequential dependencies of definitions within a single 'constdefs'
  1128 section; moreover, the declared name needs to be an identifier.  If
  1129 all fails, consider to fall back on 'consts' and 'defs' separately.
  1130 
  1131 * Improved indexed syntax and implicit structures.  First of all,
  1132 indexed syntax provides a notational device for subscripted
  1133 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1134 expressions.  Secondly, in a local context with structure
  1135 declarations, number indexes \<^sub>n or the empty index (default
  1136 number 1) refer to a certain fixed variable implicitly; option
  1137 show_structs controls printing of implicit structures.  Typical
  1138 applications of these concepts involve record types and locales.
  1139 
  1140 * New command 'no_syntax' removes grammar declarations (and
  1141 translations) resulting from the given syntax specification, which is
  1142 interpreted in the same manner as for the 'syntax' command.
  1143 
  1144 * 'Advanced' translation functions (parse_translation etc.) may depend
  1145 on the signature of the theory context being presently used for
  1146 parsing/printing, see also isar-ref manual.
  1147 
  1148 * Improved 'oracle' command provides a type-safe interface to turn an
  1149 ML expression of type theory -> T -> term into a primitive rule of
  1150 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1151 is already included here); see also FOL/ex/IffExample.thy;
  1152 INCOMPATIBILITY.
  1153 
  1154 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1155 before); "cI" is no longer bound, use "c.intro" instead.
  1156 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1157 axclasses vs. locales.
  1158 
  1159 * Improved internal renaming of symbolic identifiers -- attach primes
  1160 instead of base 26 numbers.
  1161 
  1162 * New flag show_question_marks controls printing of leading question
  1163 marks in schematic variable names.
  1164 
  1165 * In schematic variable names, *any* symbol following \<^isub> or
  1166 \<^isup> is now treated as part of the base name.  For example, the
  1167 following works without printing of awkward ".0" indexes:
  1168 
  1169   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1170     by simp
  1171 
  1172 * Inner syntax includes (*(*nested*) comments*).
  1173 
  1174 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1175 annotations as "(00...)".
  1176 
  1177 * Clear separation of logical types and nonterminals, where the latter
  1178 may only occur in 'syntax' specifications or type abbreviations.
  1179 Before that distinction was only partially implemented via type class
  1180 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1181 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1182 exotic syntax specifications may require further adaption
  1183 (e.g. Cube/Cube.thy).
  1184 
  1185 * Removed obsolete type class "logic", use the top sort {} instead.
  1186 Note that non-logical types should be declared as 'nonterminals'
  1187 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1188 specifications.
  1189 
  1190 * Attributes 'induct' and 'cases': type or set names may now be
  1191 locally fixed variables as well.
  1192 
  1193 * Simplifier: can now control the depth to which conditional rewriting
  1194 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1195 Limit.
  1196 
  1197 * Simplifier: simplification procedures may now take the current
  1198 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1199 interface), which is very useful for calling the Simplifier
  1200 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1201 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1202 low-level mk_simproc no longer applies Logic.varify internally, to
  1203 allow for use in a context of fixed variables.
  1204 
  1205 * thin_tac now works even if the assumption being deleted contains !!
  1206 or ==>.  More generally, erule now works even if the major premise of
  1207 the elimination rule contains !! or ==>.
  1208 
  1209 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1210 
  1211 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1212 from Pure, which contains all common declarations already.  Both
  1213 theories are defined via plain Isabelle/Isar .thy files.
  1214 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1215 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1216 use isatool fixcpure to adapt your theory and ML sources.
  1217 
  1218 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1219 selections of theorems in named facts via index ranges.
  1220 
  1221 * 'print_theorems': in theory mode, really print the difference
  1222 wrt. the last state (works for interactive theory development only),
  1223 in proof mode print all local facts (cf. 'print_facts');
  1224 
  1225 * 'hide': option '(open)' hides only base names.
  1226 
  1227 * More efficient treatment of intermediate checkpoints in interactive
  1228 theory development.
  1229 
  1230 * Code generator is now invoked via code_module (incremental code
  1231 generation) and code_library (modular code generation, ML structures
  1232 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1233 must be quoted when used as identifiers.
  1234 
  1235 * New 'value' command for reading, evaluating and printing terms using
  1236 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1237 quoted when used as identifier.
  1238 
  1239 
  1240 *** Locales ***
  1241 
  1242 * New commands for the interpretation of locale expressions in
  1243 theories (1), locales (2) and proof contexts (3).  These generate
  1244 proof obligations from the expression specification.  After the
  1245 obligations have been discharged, theorems of the expression are added
  1246 to the theory, target locale or proof context.  The synopsis of the
  1247 commands is a follows:
  1248 
  1249   (1) interpretation expr inst
  1250   (2) interpretation target < expr
  1251   (3) interpret expr inst
  1252 
  1253 Interpretation in theories and proof contexts require a parameter
  1254 instantiation of terms from the current context.  This is applied to
  1255 specifications and theorems of the interpreted expression.
  1256 Interpretation in locales only permits parameter renaming through the
  1257 locale expression.  Interpretation is smart in that interpretations
  1258 that are active already do not occur in proof obligations, neither are
  1259 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1260 inspect active interpretations of a particular locale.  For details,
  1261 see the Isar Reference manual.  Examples can be found in
  1262 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1263 
  1264 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1265 'interpret' instead.
  1266 
  1267 * New context element 'constrains' for adding type constraints to
  1268 parameters.
  1269 
  1270 * Context expressions: renaming of parameters with syntax
  1271 redeclaration.
  1272 
  1273 * Locale declaration: 'includes' disallowed.
  1274 
  1275 * Proper static binding of attribute syntax -- i.e. types / terms /
  1276 facts mentioned as arguments are always those of the locale definition
  1277 context, independently of the context of later invocations.  Moreover,
  1278 locale operations (renaming and type / term instantiation) are applied
  1279 to attribute arguments as expected.
  1280 
  1281 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1282 actual attributes; rare situations may require Attrib.attribute to
  1283 embed those attributes into Attrib.src that lack concrete syntax.
  1284 Attribute implementations need to cooperate properly with the static
  1285 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1286 Attrib.XXX_thm etc. already do the right thing without further
  1287 intervention.  Only unusual applications -- such as "where" or "of"
  1288 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1289 on the context and the facts involved -- may have to assign parsed
  1290 values to argument tokens explicitly.
  1291 
  1292 * Changed parameter management in theorem generation for long goal
  1293 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1294 theorem statement in rare situations.
  1295 
  1296 * Locale inspection command 'print_locale' omits notes elements.  Use
  1297 'print_locale!' to have them included in the output.
  1298 
  1299 
  1300 *** Provers ***
  1301 
  1302 * Provers/hypsubst.ML: improved version of the subst method, for
  1303 single-step rewriting: it now works in bound variable contexts. New is
  1304 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1305 rewrite a different subterm than the original subst method, which is
  1306 still available as 'simplesubst'.
  1307 
  1308 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1309 and quasi orders.
  1310 
  1311 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1312 reflexive-transitive closure of relations.
  1313 
  1314 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1315 limit (previously hard-coded with a value of 20) user-definable.
  1316 
  1317 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1318 is peformed already.  Object-logics merely need to finish their
  1319 initial simpset configuration as before.  INCOMPATIBILITY.
  1320 
  1321 
  1322 *** HOL ***
  1323 
  1324 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1325 
  1326   syntax (epsilon)
  1327     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1328 
  1329 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1330 and x-symbol; use option '-m epsilon' to get it actually printed.
  1331 Moreover, the mathematically important symbolic identifier \<epsilon>
  1332 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1333 
  1334 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1335 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1336 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1337 support corresponding Isar calculations.
  1338 
  1339 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1340 instead of ":".
  1341 
  1342 * theory SetInterval: changed the syntax for open intervals:
  1343 
  1344   Old       New
  1345   {..n(}    {..<n}
  1346   {)n..}    {n<..}
  1347   {m..n(}   {m..<n}
  1348   {)m..n}   {m<..n}
  1349   {)m..n(}  {m<..<n}
  1350 
  1351 The old syntax is still supported but will disappear in the next
  1352 release.  For conversion use the following Emacs search and replace
  1353 patterns (these are not perfect but work quite well):
  1354 
  1355   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1356   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1357 
  1358 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1359 equalities in commutative rings; method 'algebra' provides a generic
  1360 interface.
  1361 
  1362 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1363 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1364 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1365 be a tuple pattern.
  1366 
  1367 Some new syntax forms are available:
  1368 
  1369   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1370   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1371   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1372   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1373 
  1374 The latter form "\<Sum>x < k. e" used to be based on a separate
  1375 function "Summation", which has been discontinued.
  1376 
  1377 * theory Finite_Set: in structured induction proofs, the insert case
  1378 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1379 (insert F x)'.
  1380 
  1381 * The 'refute' command has been extended to support a much larger
  1382 fragment of HOL, including axiomatic type classes, constdefs and
  1383 typedefs, inductive datatypes and recursion.
  1384 
  1385 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1386 Requires zChaff with proof generation to be installed.  See
  1387 HOL/ex/SAT_Examples.thy for examples.
  1388 
  1389 * Datatype induction via method 'induct' now preserves the name of the
  1390 induction variable. For example, when proving P(xs::'a list) by
  1391 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1392 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1393 in unstructured proof scripts.
  1394 
  1395 * Reworked implementation of records.  Improved scalability for
  1396 records with many fields, avoiding performance problems for type
  1397 inference. Records are no longer composed of nested field types, but
  1398 of nested extension types. Therefore the record type only grows linear
  1399 in the number of extensions and not in the number of fields.  The
  1400 top-level (users) view on records is preserved.  Potential
  1401 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1402 old record representation. The type generated for a record is called
  1403 <record_name>_ext_type.
  1404 
  1405 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1406 proofs triggered by a record definition or a simproc (if
  1407 quick_and_dirty is enabled).  Definitions of large records can take
  1408 quite long.
  1409 
  1410 New simproc record_upd_simproc for simplification of multiple record
  1411 updates enabled by default.  Moreover, trivial updates are also
  1412 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1413 occasionally, since simplification is more powerful by default.
  1414 
  1415 * typedef: proper support for polymorphic sets, which contain extra
  1416 type-variables in the term.
  1417 
  1418 * Simplifier: automatically reasons about transitivity chains
  1419 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1420 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1421 old proofs break occasionally as simplification may now solve more
  1422 goals than previously.
  1423 
  1424 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1425 present.  Works for all partial orders (class "order"), in particular
  1426 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1427 just like y <= x.
  1428 
  1429 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1430 bound variable or a constant then the let is unfolded.  Otherwise
  1431 first a is simplified to b, and then f b is simplified to g. If
  1432 possible we abstract b from g arriving at "let x = b in h x",
  1433 otherwise we unfold the let and arrive at g.  The simproc can be
  1434 enabled/disabled by the reference use_let_simproc.  Potential
  1435 INCOMPATIBILITY since simplification is more powerful by default.
  1436 
  1437 * Classical reasoning: the meson method now accepts theorems as arguments.
  1438 
  1439 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1440 jobs to provide advice on the provability of subgoals.
  1441 
  1442 * Theory OrderedGroup and Ring_and_Field: various additions and
  1443 improvements to faciliate calculations involving equalities and
  1444 inequalities.
  1445 
  1446 The following theorems have been eliminated or modified
  1447 (INCOMPATIBILITY):
  1448 
  1449   abs_eq             now named abs_of_nonneg
  1450   abs_of_ge_0        now named abs_of_nonneg
  1451   abs_minus_eq       now named abs_of_nonpos
  1452   imp_abs_id         now named abs_of_nonneg
  1453   imp_abs_neg_id     now named abs_of_nonpos
  1454   mult_pos           now named mult_pos_pos
  1455   mult_pos_le        now named mult_nonneg_nonneg
  1456   mult_pos_neg_le    now named mult_nonneg_nonpos
  1457   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1458   mult_neg           now named mult_neg_neg
  1459   mult_neg_le        now named mult_nonpos_nonpos
  1460 
  1461 * Theory Parity: added rules for simplifying exponents.
  1462 
  1463 * Theory List:
  1464 
  1465 The following theorems have been eliminated or modified
  1466 (INCOMPATIBILITY):
  1467 
  1468   list_all_Nil       now named list_all.simps(1)
  1469   list_all_Cons      now named list_all.simps(2)
  1470   list_all_conv      now named list_all_iff
  1471   set_mem_eq         now named mem_iff
  1472 
  1473 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1474 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1475 
  1476 
  1477 *** HOL-Complex ***
  1478 
  1479 * Theory RealDef: better support for embedding natural numbers and
  1480 integers in the reals.
  1481 
  1482 The following theorems have been eliminated or modified
  1483 (INCOMPATIBILITY):
  1484 
  1485   exp_ge_add_one_self  now requires no hypotheses
  1486   real_of_int_add      reversed direction of equality (use [symmetric])
  1487   real_of_int_minus    reversed direction of equality (use [symmetric])
  1488   real_of_int_diff     reversed direction of equality (use [symmetric])
  1489   real_of_int_mult     reversed direction of equality (use [symmetric])
  1490 
  1491 * Theory RComplete: expanded support for floor and ceiling functions.
  1492 
  1493 * Theory Ln is new, with properties of the natural logarithm
  1494 
  1495 * Hyperreal: There is a new type constructor "star" for making
  1496 nonstandard types.  The old type names are now type synonyms:
  1497 
  1498   hypreal = real star
  1499   hypnat = nat star
  1500   hcomplex = complex star
  1501 
  1502 * Hyperreal: Many groups of similarly-defined constants have been
  1503 replaced by polymorphic versions (INCOMPATIBILITY):
  1504 
  1505   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1506 
  1507   starset      <-- starsetNat, starsetC
  1508   *s*          <-- *sNat*, *sc*
  1509   starset_n    <-- starsetNat_n, starsetC_n
  1510   *sn*         <-- *sNatn*, *scn*
  1511   InternalSets <-- InternalNatSets, InternalCSets
  1512 
  1513   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1514   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1515   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1516   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1517   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1518 
  1519 * Hyperreal: Many type-specific theorems have been removed in favor of
  1520 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1521 
  1522   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1523   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1524   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1525   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1526   right_minus <-- hypreal_add_minus
  1527   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1528   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1529   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1530   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1531   mult_1_right <-- hcomplex_mult_one_right
  1532   mult_zero_left <-- hcomplex_mult_zero_left
  1533   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1534   right_distrib <-- hypnat_add_mult_distrib2
  1535   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1536   right_inverse <-- hypreal_mult_inverse
  1537   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1538   order_refl <-- {hypreal,hypnat}_le_refl
  1539   order_trans <-- {hypreal,hypnat}_le_trans
  1540   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1541   order_less_le <-- {hypreal,hypnat}_less_le
  1542   linorder_linear <-- {hypreal,hypnat}_le_linear
  1543   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1544   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1545   add_nonneg_nonneg <-- hypreal_le_add_order
  1546 
  1547 * Hyperreal: Separate theorems having to do with type-specific
  1548 versions of constants have been merged into theorems that apply to the
  1549 new polymorphic constants (INCOMPATIBILITY):
  1550 
  1551   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1552   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1553   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1554   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1555   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1556   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1557   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1558   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1559   STAR_diff <-- {STAR,STARC}_diff
  1560   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1561     STARC_hcomplex_of_complex}_image_subset
  1562   starset_n_Un <-- starset{Nat,C}_n_Un
  1563   starset_n_Int <-- starset{Nat,C}_n_Int
  1564   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1565   starset_n_diff <-- starset{Nat,C}_n_diff
  1566   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1567   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1568   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1569   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1570   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1571   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1572   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1573   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1574   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1575   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1576   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1577   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1578   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1579   starfun_diff <-- starfun{C,RC,CR}_diff
  1580   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1581   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1582   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1583   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1584   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1585   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1586   starfun_Id <-- starfunC_Id
  1587   starfun_approx <-- starfun{Nat,CR}_approx
  1588   starfun_capprox <-- starfun{C,RC}_capprox
  1589   starfun_abs <-- starfunNat_rabs
  1590   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1591   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1592   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1593   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1594   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1595   starfun_add_approx <-- starfunCR_add_approx
  1596   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1597   starfun_divide <-- starfun{C,CR,RC}_divide
  1598   starfun_n <-- starfun{Nat,C}_n
  1599   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1600   starfun_n_add <-- starfun{Nat,C}_n_add
  1601   starfun_n_add_minus <-- starfunNat_n_add_minus
  1602   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1603   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1604   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1605 
  1606   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1607   star_n_minus <-- {hypreal,hcomplex}_minus
  1608   star_n_diff <-- {hypreal,hcomplex}_diff
  1609   star_n_mult <-- {hypreal,hcomplex}_mult
  1610   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1611   star_n_le <-- {hypreal,hypnat}_le
  1612   star_n_less <-- {hypreal,hypnat}_less
  1613   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1614   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1615   star_n_abs <-- hypreal_hrabs
  1616   star_n_divide <-- hcomplex_divide
  1617 
  1618   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1619   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1620   star_of_diff <-- hypreal_of_real_diff
  1621   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1622   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1623   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1624   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1625   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1626   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1627   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1628   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1629   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1630   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1631   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1632   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1633   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1634   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1635   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1636   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1637   star_of_power <-- hypreal_of_real_power
  1638   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1639 
  1640 * Hyperreal: new method "transfer" that implements the transfer
  1641 principle of nonstandard analysis. With a subgoal that mentions
  1642 nonstandard types like "'a star", the command "apply transfer"
  1643 replaces it with an equivalent one that mentions only standard types.
  1644 To be successful, all free variables must have standard types; non-
  1645 standard variables must have explicit universal quantifiers.
  1646 
  1647 * Hyperreal: A theory of Taylor series.
  1648 
  1649 
  1650 *** HOLCF ***
  1651 
  1652 * Discontinued special version of 'constdefs' (which used to support
  1653 continuous functions) in favor of the general Pure one with full
  1654 type-inference.
  1655 
  1656 * New simplification procedure for solving continuity conditions; it
  1657 is much faster on terms with many nested lambda abstractions (cubic
  1658 instead of exponential time).
  1659 
  1660 * New syntax for domain package: selector names are now optional.
  1661 Parentheses should be omitted unless argument is lazy, for example:
  1662 
  1663   domain 'a stream = cons "'a" (lazy "'a stream")
  1664 
  1665 * New command 'fixrec' for defining recursive functions with pattern
  1666 matching; defining multiple functions with mutual recursion is also
  1667 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1668 sinr, or any data constructor defined by the domain package. The given
  1669 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1670 syntax and examples.
  1671 
  1672 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1673 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1674 but the proof obligation additionally includes an admissibility
  1675 requirement. The packages generate instances of class cpo or pcpo,
  1676 with continuity and strictness theorems for Rep and Abs.
  1677 
  1678 * HOLCF: Many theorems have been renamed according to a more standard naming
  1679 scheme (INCOMPATIBILITY):
  1680 
  1681   foo_inject:  "foo$x = foo$y ==> x = y"
  1682   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1683   foo_less:    "(foo$x << foo$y) = (x << y)"
  1684   foo_strict:  "foo$UU = UU"
  1685   foo_defined: "... ==> foo$x ~= UU"
  1686   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1687 
  1688 
  1689 *** ZF ***
  1690 
  1691 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1692 including the First Isomorphism Theorem (on quotienting by the kernel
  1693 of a homomorphism).
  1694 
  1695 * ZF/Simplifier: install second copy of type solver that actually
  1696 makes use of TC rules declared to Isar proof contexts (or locales);
  1697 the old version is still required for ML proof scripts.
  1698 
  1699 
  1700 *** Cube ***
  1701 
  1702 * Converted to Isar theory format; use locales instead of axiomatic
  1703 theories.
  1704 
  1705 
  1706 *** ML ***
  1707 
  1708 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1709 for ||>, ||>>, |>>,
  1710 
  1711 * Pure/library.ML no longer defines its own option datatype, but uses
  1712 that of the SML basis, which has constructors NONE and SOME instead of
  1713 None and Some, as well as exception Option.Option instead of OPTION.
  1714 The functions the, if_none, is_some, is_none have been adapted
  1715 accordingly, while Option.map replaces apsome.
  1716 
  1717 * Pure/library.ML: the exception LIST has been given up in favour of
  1718 the standard exceptions Empty and Subscript, as well as
  1719 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1720 superceded by the standard hd and tl functions etc.
  1721 
  1722 A number of basic list functions are no longer exported to the ML
  1723 toplevel, as they are variants of predefined functions.  The following
  1724 suggests how one can translate existing code:
  1725 
  1726     rev_append xs ys = List.revAppend (xs, ys)
  1727     nth_elem (i, xs) = List.nth (xs, i)
  1728     last_elem xs = List.last xs
  1729     flat xss = List.concat xss
  1730     seq fs = List.app fs
  1731     partition P xs = List.partition P xs
  1732     mapfilter f xs = List.mapPartial f xs
  1733 
  1734 * Pure/library.ML: several combinators for linear functional
  1735 transformations, notably reverse application and composition:
  1736 
  1737   x |> f                f #> g
  1738   (x, y) |-> f          f #-> g
  1739 
  1740 * Pure/library.ML: introduced/changed precedence of infix operators:
  1741 
  1742   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1743   infix 2 ?;
  1744   infix 3 o oo ooo oooo;
  1745   infix 4 ~~ upto downto;
  1746 
  1747 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1748 infix operators.
  1749 
  1750 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1751 fold_map support linear functional transformations and nesting.  For
  1752 example:
  1753 
  1754   fold f [x1, ..., xN] y =
  1755     y |> f x1 |> ... |> f xN
  1756 
  1757   (fold o fold) f [xs1, ..., xsN] y =
  1758     y |> fold f xs1 |> ... |> fold f xsN
  1759 
  1760   fold f [x1, ..., xN] =
  1761     f x1 #> ... #> f xN
  1762 
  1763   (fold o fold) f [xs1, ..., xsN] =
  1764     fold f xs1 #> ... #> fold f xsN
  1765 
  1766 * Pure/library.ML: the following selectors on type 'a option are
  1767 available:
  1768 
  1769   the:               'a option -> 'a  (*partial*)
  1770   these:             'a option -> 'a  where 'a = 'b list
  1771   the_default: 'a -> 'a option -> 'a
  1772   the_list:          'a option -> 'a list
  1773 
  1774 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1775 basic operations for association lists, following natural argument
  1776 order; moreover the explicit equality predicate passed here avoids
  1777 potentially expensive polymorphic runtime equality checks.
  1778 The old functions may be expressed as follows:
  1779 
  1780   assoc = uncurry (AList.lookup (op =))
  1781   assocs = these oo AList.lookup (op =)
  1782   overwrite = uncurry (AList.update (op =)) o swap
  1783 
  1784 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1785 
  1786   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1787   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1788 
  1789 replacing make_keylist and keyfilter (occassionally used)
  1790 Naive rewrites:
  1791 
  1792   make_keylist = AList.make
  1793   keyfilter = AList.find (op =)
  1794 
  1795 * eq_fst and eq_snd now take explicit equality parameter, thus
  1796   avoiding eqtypes. Naive rewrites:
  1797 
  1798     eq_fst = eq_fst (op =)
  1799     eq_snd = eq_snd (op =)
  1800 
  1801 * Removed deprecated apl and apr (rarely used).
  1802   Naive rewrites:
  1803 
  1804     apl (n, op) =>>= curry op n
  1805     apr (op, m) =>>= fn n => op (n, m)
  1806 
  1807 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1808 provides a reasonably efficient light-weight implementation of sets as
  1809 lists.
  1810 
  1811 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1812 few new operations; existing lookup and update are now curried to
  1813 follow natural argument order (for use with fold etc.);
  1814 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1815 
  1816 * Pure/General: output via the Isabelle channels of
  1817 writeln/warning/error etc. is now passed through Output.output, with a
  1818 hook for arbitrary transformations depending on the print_mode
  1819 (cf. Output.add_mode -- the first active mode that provides a output
  1820 function wins).  Already formatted output may be embedded into further
  1821 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1822 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1823 accommodate easy composition of diagnostic messages etc.  Programmers
  1824 rarely need to care about Output.output or Output.raw at all, with
  1825 some notable exceptions: Output.output is required when bypassing the
  1826 standard channels (writeln etc.), or in token translations to produce
  1827 properly formatted results; Output.raw is required when capturing
  1828 already output material that will eventually be presented to the user
  1829 a second time.  For the default print mode, both Output.output and
  1830 Output.raw have no effect.
  1831 
  1832 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1833 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1834 cumulative results are displayed at the end of a batch session.
  1835 
  1836 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1837 replaced by File.platform_path and File.shell_path (with appropriate
  1838 hooks).  This provides a clean interface for unusual systems where the
  1839 internal and external process view of file names are different.
  1840 
  1841 * Pure: more efficient orders for basic syntactic entities: added
  1842 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1843 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1844 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1845 orders now -- potential INCOMPATIBILITY for code that depends on a
  1846 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1847 Library.sort_strings on result).
  1848 
  1849 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1850 fold_types traverse types/terms from left to right, observing natural
  1851 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1852 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1853 
  1854 * Pure: name spaces have been refined, with significant changes of the
  1855 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1856 to extern(_table).  The plain name entry path is superceded by a
  1857 general 'naming' context, which also includes the 'policy' to produce
  1858 a fully qualified name and external accesses of a fully qualified
  1859 name; NameSpace.extend is superceded by context dependent
  1860 Sign.declare_name.  Several theory and proof context operations modify
  1861 the naming context.  Especially note Theory.restore_naming and
  1862 ProofContext.restore_naming to get back to a sane state; note that
  1863 Theory.add_path is no longer sufficient to recover from
  1864 Theory.absolute_path in particular.
  1865 
  1866 * Pure: new flags short_names (default false) and unique_names
  1867 (default true) for controlling output of qualified names.  If
  1868 short_names is set, names are printed unqualified.  If unique_names is
  1869 reset, the name prefix is reduced to the minimum required to achieve
  1870 the original result when interning again, even if there is an overlap
  1871 with earlier declarations.
  1872 
  1873 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1874 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1875 (useful for printing error messages).  INCOMPATIBILITY.
  1876 
  1877 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1878 Theory.theory are now identified, referring to the universal
  1879 Context.theory (see Pure/context.ML).  Actual signature and theory
  1880 content is managed as theory data.  The old code and interfaces were
  1881 spread over many files and structures; the new arrangement introduces
  1882 considerable INCOMPATIBILITY to gain more clarity:
  1883 
  1884   Context -- theory management operations (name, identity, inclusion,
  1885     parents, ancestors, merge, etc.), plus generic theory data;
  1886 
  1887   Sign -- logical signature and syntax operations (declaring consts,
  1888     types, etc.), plus certify/read for common entities;
  1889 
  1890   Theory -- logical theory operations (stating axioms, definitions,
  1891     oracles), plus a copy of logical signature operations (consts,
  1892     types, etc.); also a few basic management operations (Theory.copy,
  1893     Theory.merge, etc.)
  1894 
  1895 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1896 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1897 for convenience -- they merely return the theory.
  1898 
  1899 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1900 
  1901 * Pure: the Isar proof context type is already defined early in Pure
  1902 as Context.proof (note that ProofContext.context and Proof.context are
  1903 aliases, where the latter is the preferred name).  This enables other
  1904 Isabelle components to refer to that type even before Isar is present.
  1905 
  1906 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1907 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1908 any of these kinds.  For example, Sign.intern typeK is now
  1909 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1910 Theory.hide_types.  Also note that former
  1911 Theory.hide_classes/types/consts are now
  1912 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1913 internalize their arguments!  INCOMPATIBILITY.
  1914 
  1915 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1916 datatype thmref (with constructors Name and NameSelection) instead of
  1917 plain string -- INCOMPATIBILITY;
  1918 
  1919 * Pure: cases produced by proof methods specify options, where NONE
  1920 means to remove case bindings -- INCOMPATIBILITY in
  1921 (RAW_)METHOD_CASES.
  1922 
  1923 * Pure: the following operations retrieve axioms or theorems from a
  1924 theory node or theory hierarchy, respectively:
  1925 
  1926   Theory.axioms_of: theory -> (string * term) list
  1927   Theory.all_axioms_of: theory -> (string * term) list
  1928   PureThy.thms_of: theory -> (string * thm) list
  1929   PureThy.all_thms_of: theory -> (string * thm) list
  1930 
  1931 * Pure: print_tac now outputs the goal through the trace channel.
  1932 
  1933 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1934 Reference Toplevel.debug (default false) controls detailed printing
  1935 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1936 controls execution profiling -- set to 1 for time and 2 for space
  1937 (both increase the runtime).
  1938 
  1939 * Isar session: The initial use of ROOT.ML is now always timed,
  1940 i.e. the log will show the actual process times, in contrast to the
  1941 elapsed wall-clock time that the outer shell wrapper produces.
  1942 
  1943 * Simplifier: improved handling of bound variables (nameless
  1944 representation, avoid allocating new strings).  Simprocs that invoke
  1945 the Simplifier recursively should use Simplifier.inherit_bounds to
  1946 avoid local name clashes.  Failure to do so produces warnings
  1947 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1948 for further details.
  1949 
  1950 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1951 bindings for all theorems stored within a given theory; this may help
  1952 in porting non-Isar theories to Isar ones, while keeping ML proof
  1953 scripts for the time being.
  1954 
  1955 * ML operator HTML.with_charset specifies the charset begin used for
  1956 generated HTML files.  For example:
  1957 
  1958   HTML.with_charset "utf-8" use_thy "Hebrew";
  1959   HTML.with_charset "utf-8" use_thy "Chinese";
  1960 
  1961 
  1962 *** System ***
  1963 
  1964 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1965 isabelle, isatool etc.).
  1966 
  1967 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1968 isatool doc, isatool mkdir, display_drafts etc.).
  1969 
  1970 * isatool usedir: option -f allows specification of the ML file to be
  1971 used by Isabelle; default is ROOT.ML.
  1972 
  1973 * New isatool version outputs the version identifier of the Isabelle
  1974 distribution being used.
  1975 
  1976 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1977 (containing Boolean satisfiability problems) into Isabelle/HOL
  1978 theories.
  1979 
  1980 
  1981 
  1982 New in Isabelle2004 (April 2004)
  1983 --------------------------------
  1984 
  1985 *** General ***
  1986 
  1987 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1988   Replaces linorder.ML.
  1989 
  1990 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1991   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1992   (\<a>...\<z>), are now considered normal letters, and can therefore
  1993   be used anywhere where an ASCII letter (a...zA...Z) has until
  1994   now. COMPATIBILITY: This obviously changes the parsing of some
  1995   terms, especially where a symbol has been used as a binder, say
  1996   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1997   as an identifier.  Fix it by inserting a space around former
  1998   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1999   existing theory and ML files.
  2000 
  2001 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2002 
  2003 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2004   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2005   a normal (but invisible) letter. For multiple letter subscripts repeat
  2006   \<^isub> like this: x\<^isub>1\<^isub>2.
  2007 
  2008 * Pure: There are now sub-/superscripts that can span more than one
  2009   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2010   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2011   superscript. The new control characters are not identifier parts.
  2012 
  2013 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2014   content of "..." to the latex file instead of \isacntrl... . The "..."
  2015   may consist of any printable characters excluding the end bracket >.
  2016 
  2017 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2018   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2019   declare constants "final", which prevents their being given a definition
  2020   later.  It is useful for constants whose behaviour is fixed axiomatically
  2021   rather than definitionally, such as the meta-logic connectives.
  2022 
  2023 * Pure: 'instance' now handles general arities with general sorts
  2024   (i.e. intersections of classes),
  2025 
  2026 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2027   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2028   It can be changed to alter the colors/layout of generated pages.
  2029 
  2030 
  2031 *** Isar ***
  2032 
  2033 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2034   cut_tac, subgoal_tac and thin_tac:
  2035   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2036     locales are no longer forced to write Isar proof scripts.
  2037     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2038     emulations.
  2039   - INCOMPATIBILITY: names of variables to be instantiated may no
  2040     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2041     This is consistent with the instantiation attribute "where".
  2042 
  2043 * Attributes "where" and "of":
  2044   - Now take type variables of instantiated theorem into account when reading
  2045     the instantiation string.  This fixes a bug that caused instantiated
  2046     theorems to have too special types in some circumstances.
  2047   - "where" permits explicit instantiations of type variables.
  2048 
  2049 * Calculation commands "moreover" and "also" no longer interfere with
  2050   current facts ("this"), admitting arbitrary combinations with "then"
  2051   and derived forms.
  2052 
  2053 * Locales:
  2054   - Goal statements involving the context element "includes" no longer
  2055     generate theorems with internal delta predicates (those ending on
  2056     "_axioms") in the premise.
  2057     Resolve particular premise with <locale>.intro to obtain old form.
  2058   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2059     specification and "includes" elements in goal statement.
  2060   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2061     [intro?] and [elim?] (respectively) by default.
  2062   - Experimental command for instantiation of locales in proof contexts:
  2063         instantiate <label>[<attrs>]: <loc>
  2064     Instantiates locale <loc> and adds all its theorems to the current context
  2065     taking into account their attributes.  Label and attrs are optional
  2066     modifiers, like in theorem declarations.  If present, names of
  2067     instantiated theorems are qualified with <label>, and the attributes
  2068     <attrs> are applied after any attributes these theorems might have already.
  2069       If the locale has assumptions, a chained fact of the form
  2070     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2071     are derived.  The command does not support old-style locales declared
  2072     with "locale (open)".
  2073       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2074 
  2075 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2076   (Isar) contexts.
  2077 
  2078 
  2079 *** HOL ***
  2080 
  2081 * Proof import: new image HOL4 contains the imported library from
  2082   the HOL4 system with about 2500 theorems. It is imported by
  2083   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2084   can be used like any other Isabelle image.  See
  2085   HOL/Import/HOL/README for more information.
  2086 
  2087 * Simplifier:
  2088   - Much improved handling of linear and partial orders.
  2089     Reasoners for linear and partial orders are set up for type classes
  2090     "linorder" and "order" respectively, and are added to the default simpset
  2091     as solvers.  This means that the simplifier can build transitivity chains
  2092     to solve goals from the assumptions.
  2093   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2094     of blast or auto after simplification become unnecessary because the goal
  2095     is solved by simplification already.
  2096 
  2097 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2098     all proved in axiomatic type classes for semirings, rings and fields.
  2099 
  2100 * Numerics:
  2101   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2102     now formalized using the Ring_and_Field theory mentioned above.
  2103   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2104     than before, because now they are set up once in a generic manner.
  2105   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2106     Look for the general versions in Ring_and_Field (and Power if they concern
  2107     exponentiation).
  2108 
  2109 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2110 
  2111 * Records:
  2112   - Record types are now by default printed with their type abbreviation
  2113     instead of the list of all field types. This can be configured via
  2114     the reference "print_record_type_abbr".
  2115   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2116     (not enabled by default).
  2117   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2118     EX x. x = sel r to True (not enabled by default).
  2119   - Tactic "record_split_simp_tac" to split and simplify records added.
  2120 
  2121 * 'specification' command added, allowing for definition by
  2122   specification.  There is also an 'ax_specification' command that
  2123   introduces the new constants axiomatically.
  2124 
  2125 * arith(_tac) is now able to generate counterexamples for reals as well.
  2126 
  2127 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2128 
  2129 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2130   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2131 
  2132 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2133   matrix theory to linear programming.
  2134 
  2135 * Unions and Intersections:
  2136   The latex output syntax of UN and INT has been changed
  2137   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2138   i.e. the index formulae has become a subscript.
  2139   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2140 
  2141 * Unions and Intersections over Intervals:
  2142   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2143   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2144   like in normal math, and corresponding versions for < and for intersection.
  2145 
  2146 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2147   lexicographic dictonary ordering has been added as "lexord".
  2148 
  2149 * ML: the legacy theory structures Int and List have been removed. They had
  2150   conflicted with ML Basis Library structures having the same names.
  2151 
  2152 * 'refute' command added to search for (finite) countermodels.  Only works
  2153   for a fragment of HOL.  The installation of an external SAT solver is
  2154   highly recommended.  See "HOL/Refute.thy" for details.
  2155 
  2156 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2157   formulae under an assignment of free variables to random values.
  2158   In contrast to 'refute', it can deal with inductive datatypes,
  2159   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2160   for examples.
  2161 
  2162 
  2163 *** HOLCF ***
  2164 
  2165 * Streams now come with concatenation and are part of the HOLCF image
  2166 
  2167 
  2168 
  2169 New in Isabelle2003 (May 2003)
  2170 ------------------------------
  2171 
  2172 *** General ***
  2173 
  2174 * Provers/simplifier:
  2175 
  2176   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2177     Assumptions are now subject to complete mutual simplification,
  2178     not just from left to right. The simplifier now preserves
  2179     the order of assumptions.
  2180 
  2181     Potential INCOMPATIBILITY:
  2182 
  2183     -- simp sometimes diverges where the old version did
  2184        not, e.g. invoking simp on the goal
  2185 
  2186         [| P (f x); y = x; f x = f y |] ==> Q
  2187 
  2188        now gives rise to the infinite reduction sequence
  2189 
  2190         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2191 
  2192        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2193        kind of problem.
  2194 
  2195     -- Tactics combining classical reasoner and simplification (such as auto)
  2196        are also affected by this change, because many of them rely on
  2197        simp. They may sometimes diverge as well or yield a different numbers
  2198        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2199        in case of problems. Sometimes subsequent calls to the classical
  2200        reasoner will fail because a preceeding call to the simplifier too
  2201        eagerly simplified the goal, e.g. deleted redundant premises.
  2202 
  2203   - The simplifier trace now shows the names of the applied rewrite rules
  2204 
  2205   - You can limit the number of recursive invocations of the simplifier
  2206     during conditional rewriting (where the simplifie tries to solve the
  2207     conditions before applying the rewrite rule):
  2208     ML "simp_depth_limit := n"
  2209     where n is an integer. Thus you can force termination where previously
  2210     the simplifier would diverge.
  2211 
  2212   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2213 
  2214   - No longer aborts on failed congruence proof.  Instead, the
  2215     congruence is ignored.
  2216 
  2217 * Pure: New generic framework for extracting programs from constructive
  2218   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2219   as HOL/Extraction for some case studies.
  2220 
  2221 * Pure: The main goal of the proof state is no longer shown by default, only
  2222 the subgoals. This behaviour is controlled by a new flag.
  2223    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2224 (ML: Proof.show_main_goal).
  2225 
  2226 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2227 rules whose conclusion matches subgoal 1:
  2228       PG menu: Isabelle/Isar -> Show me -> matching rules
  2229 The rules are ordered by how closely they match the subgoal.
  2230 In particular, rules that solve a subgoal outright are displayed first
  2231 (or rather last, the way they are printed).
  2232 (ML: ProofGeneral.print_intros())
  2233 
  2234 * Pure: New flag trace_unify_fail causes unification to print
  2235 diagnostic information (PG: in trace buffer) when it fails. This is
  2236 useful for figuring out why single step proofs like rule, erule or
  2237 assumption failed.
  2238 
  2239 * Pure: Locale specifications now produce predicate definitions
  2240 according to the body of text (covering assumptions modulo local
  2241 definitions); predicate "loc_axioms" covers newly introduced text,
  2242 while "loc" is cumulative wrt. all included locale expressions; the
  2243 latter view is presented only on export into the global theory
  2244 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2245 on the old view without predicates;
  2246 
  2247 * Pure: predefined locales "var" and "struct" are useful for sharing
  2248 parameters (as in CASL, for example); just specify something like
  2249 ``var x + var y + struct M'' as import;
  2250 
  2251 * Pure: improved thms_containing: proper indexing of facts instead of
  2252 raw theorems; check validity of results wrt. current name space;
  2253 include local facts of proof configuration (also covers active
  2254 locales), cover fixed variables in index; may use "_" in term
  2255 specification; an optional limit for the number of printed facts may
  2256 be given (the default is 40);
  2257 
  2258 * Pure: disallow duplicate fact bindings within new-style theory files
  2259 (batch-mode only);
  2260 
  2261 * Provers: improved induct method: assumptions introduced by case
  2262 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2263 the goal statement); "foo" still refers to all facts collectively;
  2264 
  2265 * Provers: the function blast.overloaded has been removed: all constants
  2266 are regarded as potentially overloaded, which improves robustness in exchange
  2267 for slight decrease in efficiency;
  2268 
  2269 * Provers/linorder: New generic prover for transitivity reasoning over
  2270 linear orders.  Note: this prover is not efficient!
  2271 
  2272 * Isar: preview of problems to finish 'show' now produce an error
  2273 rather than just a warning (in interactive mode);
  2274 
  2275 
  2276 *** HOL ***
  2277 
  2278 * arith(_tac)
  2279 
  2280  - Produces a counter example if it cannot prove a goal.
  2281    Note that the counter example may be spurious if the goal is not a formula
  2282    of quantifier-free linear arithmetic.
  2283    In ProofGeneral the counter example appears in the trace buffer.
  2284 
  2285  - Knows about div k and mod k where k is a numeral of type nat or int.
  2286 
  2287  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2288    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2289    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2290 
  2291 * simp's arithmetic capabilities have been enhanced a bit: it now
  2292 takes ~= in premises into account (by performing a case split);
  2293 
  2294 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2295 are distributed over a sum of terms;
  2296 
  2297 * New tactic "trans_tac" and method "trans" instantiate
  2298 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2299 "<=", "<" and "=").
  2300 
  2301 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2302 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2303 
  2304 * 'typedef' command has new option "open" to suppress the set
  2305 definition;
  2306 
  2307 * functions Min and Max on finite sets have been introduced (theory
  2308 Finite_Set);
  2309 
  2310 * attribute [symmetric] now works for relations as well; it turns
  2311 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2312 
  2313 * induct over a !!-quantified statement (say !!x1..xn):
  2314   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2315 
  2316 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2317 %x. None. Warning: empty_def now refers to the previously hidden definition
  2318 of the empty set.
  2319 
  2320 * Algebra: formalization of classical algebra.  Intended as base for
  2321 any algebraic development in Isabelle.  Currently covers group theory
  2322 (up to Sylow's theorem) and ring theory (Universal Property of
  2323 Univariate Polynomials).  Contributions welcome;
  2324 
  2325 * GroupTheory: deleted, since its material has been moved to Algebra;
  2326 
  2327 * Complex: new directory of the complex numbers with numeric constants,
  2328 nonstandard complex numbers, and some complex analysis, standard and
  2329 nonstandard (Jacques Fleuriot);
  2330 
  2331 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2332 
  2333 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2334 Fleuriot);
  2335 
  2336 * Real/HahnBanach: updated and adapted to locales;
  2337 
  2338 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2339 Gray and Kramer);
  2340 
  2341 * UNITY: added the Meier-Sanders theory of progress sets;
  2342 
  2343 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2344 as abstract algorithms, instantiated to the JVM;
  2345 
  2346 * Bali: Java source language formalization. Type system, operational
  2347 semantics, axiomatic semantics. Supported language features:
  2348 classes, interfaces, objects,virtual methods, static methods,
  2349 static/instance fields, arrays, access modifiers, definite
  2350 assignment, exceptions.
  2351 
  2352 
  2353 *** ZF ***
  2354 
  2355 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2356 universe, etc.);
  2357 
  2358 * Main ZF: virtually all theories converted to new-style format;
  2359 
  2360 
  2361 *** ML ***
  2362 
  2363 * Pure: Tactic.prove provides sane interface for internal proofs;
  2364 omits the infamous "standard" operation, so this is more appropriate
  2365 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2366 
  2367 * Pure: improved error reporting of simprocs;
  2368 
  2369 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2370 up simprocs;
  2371 
  2372 
  2373 *** Document preparation ***
  2374 
  2375 * uses \par instead of \\ for line breaks in theory text. This may
  2376 shift some page breaks in large documents. To get the old behaviour
  2377 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2378 
  2379 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2380 other packages
  2381 
  2382 * \<euro> now needs package babel/greek instead of marvosym (which
  2383 broke \Rightarrow)
  2384 
  2385 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2386 textcomp package)
  2387 
  2388 
  2389 
  2390 New in Isabelle2002 (March 2002)
  2391 --------------------------------
  2392 
  2393 *** Document preparation ***
  2394 
  2395 * greatly simplified document preparation setup, including more
  2396 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2397 instructive isatool mkdir; users should basically be able to get
  2398 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2399 users may run a separate document processing stage manually like this:
  2400 "isatool usedir -D output HOL Test && isatool document Test/output";
  2401 
  2402 * theory dependency graph may now be incorporated into documents;
  2403 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2404 with \includegraphics of LaTeX;
  2405 
  2406 * proper spacing of consecutive markup elements, especially text
  2407 blocks after section headings;
  2408 
  2409 * support bold style (for single symbols only), input syntax is like
  2410 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2411 
  2412 * \<bullet> is now output as bold \cdot by default, which looks much
  2413 better in printed text;
  2414 
  2415 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2416 note that these symbols are currently unavailable in Proof General /
  2417 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2418 
  2419 * isatool latex no longer depends on changed TEXINPUTS, instead
  2420 isatool document copies the Isabelle style files to the target
  2421 location;
  2422 
  2423 
  2424 *** Isar ***
  2425 
  2426 * Pure/Provers: improved proof by cases and induction;
  2427   - 'case' command admits impromptu naming of parameters (such as
  2428     "case (Suc n)");
  2429   - 'induct' method divinates rule instantiation from the inductive
  2430     claim; no longer requires excessive ?P bindings for proper
  2431     instantiation of cases;
  2432   - 'induct' method properly enumerates all possibilities of set/type
  2433     rules; as a consequence facts may be also passed through *type*
  2434     rules without further ado;
  2435   - 'induct' method now derives symbolic cases from the *rulified*
  2436     rule (before it used to rulify cases stemming from the internal
  2437     atomized version); this means that the context of a non-atomic
  2438     statement becomes is included in the hypothesis, avoiding the
  2439     slightly cumbersome show "PROP ?case" form;
  2440   - 'induct' may now use elim-style induction rules without chaining
  2441     facts, using ``missing'' premises from the goal state; this allows
  2442     rules stemming from inductive sets to be applied in unstructured
  2443     scripts, while still benefitting from proper handling of non-atomic
  2444     statements; NB: major inductive premises need to be put first, all
  2445     the rest of the goal is passed through the induction;
  2446   - 'induct' proper support for mutual induction involving non-atomic
  2447     rule statements (uses the new concept of simultaneous goals, see
  2448     below);
  2449   - append all possible rule selections, but only use the first
  2450     success (no backtracking);
  2451   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2452   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2453   - added 'print_induct_rules' (covered by help item in recent Proof
  2454     General versions);
  2455   - moved induct/cases attributes to Pure, methods to Provers;
  2456   - generic method setup instantiated for FOL and HOL;
  2457 
  2458 * Pure: support multiple simultaneous goal statements, for example
  2459 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2460 meta-level mechanism, this acts as if several individual goals had
  2461 been stated separately; in particular common proof methods need to be
  2462 repeated in order to cover all claims; note that a single elimination
  2463 step is *not* sufficient to establish the two conjunctions, so this
  2464 fails:
  2465 
  2466   assume "A & B" then have A and B ..   (*".." fails*)
  2467 
  2468 better use "obtain" in situations as above; alternative refer to
  2469 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2470 
  2471 * Pure: proper integration with ``locales''; unlike the original
  2472 version by Florian Kammller, Isar locales package high-level proof
  2473 contexts rather than raw logical ones (e.g. we admit to include
  2474 attributes everywhere); operations on locales include merge and
  2475 rename; support for implicit arguments (``structures''); simultaneous
  2476 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2477 some examples;
  2478 
  2479 * Pure: the following commands have been ``localized'', supporting a
  2480 target locale specification "(in name)": 'lemma', 'theorem',
  2481 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2482 stored both within the locale and at the theory level (exported and
  2483 qualified by the locale name);
  2484 
  2485 * Pure: theory goals may now be specified in ``long'' form, with
  2486 ad-hoc contexts consisting of arbitrary locale elements. for example
  2487 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2488 definitions may be given, too); the result is a meta-level rule with
  2489 the context elements being discharged in the obvious way;
  2490 
  2491 * Pure: new proof command 'using' allows to augment currently used
  2492 facts after a goal statement ('using' is syntactically analogous to
  2493 'apply', but acts on the goal's facts only); this allows chained facts
  2494 to be separated into parts given before and after a claim, as in
  2495 ``from a and b have C using d and e <proof>'';
  2496 
  2497 * Pure: renamed "antecedent" case to "rule_context";
  2498 
  2499 * Pure: new 'judgment' command records explicit information about the
  2500 object-logic embedding (used by several tools internally); no longer
  2501 use hard-wired "Trueprop";
  2502 
  2503 * Pure: added 'corollary' command;
  2504 
  2505 * Pure: fixed 'token_translation' command;
  2506 
  2507 * Pure: removed obsolete 'exported' attribute;
  2508 
  2509 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2510 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2511 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2512 
  2513 * Pure: method 'atomize' presents local goal premises as object-level
  2514 statements (atomic meta-level propositions); setup controlled via
  2515 rewrite rules declarations of 'atomize' attribute; example
  2516 application: 'induct' method with proper rule statements in improper
  2517 proof *scripts*;
  2518 
  2519 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2520 now consider the syntactic context of assumptions, giving a better
  2521 chance to get type-inference of the arguments right (this is
  2522 especially important for locales);
  2523 
  2524 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2525 mode;
  2526 
  2527 * Pure/obtain: the formal conclusion "thesis", being marked as
  2528 ``internal'', may no longer be reference directly in the text;
  2529 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2530 situations;
  2531 
  2532 * Pure: generic 'sym' attribute which declares a rule both as pure
  2533 'elim?' and for the 'symmetric' operation;
  2534 
  2535 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2536 text; the fixed correlation with particular command syntax has been
  2537 discontinued;
  2538 
  2539 * Pure: new method 'rules' is particularly well-suited for proof
  2540 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2541 but often produces more compact proof terms with less detours;
  2542 
  2543 * Pure/Provers/classical: simplified integration with pure rule
  2544 attributes and methods; the classical "intro?/elim?/dest?"
  2545 declarations coincide with the pure ones; the "rule" method no longer
  2546 includes classically swapped intros; "intro" and "elim" methods no
  2547 longer pick rules from the context; also got rid of ML declarations
  2548 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2549 INCOMPATIBILITY;
  2550 
  2551 * Provers/classical: attribute 'swapped' produces classical inversions
  2552 of introduction rules;
  2553 
  2554 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2555 rules instead of full simplifier context; 'iff' attribute handles
  2556 conditional rules;
  2557 
  2558 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2559 
  2560 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2561 "(permissive)" option to recover old behavior;
  2562 
  2563 * HOL: 'inductive' no longer features separate (collective) attributes
  2564 for 'intros' (was found too confusing);
  2565 
  2566 * HOL: properly declared induction rules less_induct and
  2567 wf_induct_rule;
  2568 
  2569 
  2570 *** HOL ***
  2571 
  2572 * HOL: moved over to sane numeral syntax; the new policy is as
  2573 follows:
  2574 
  2575   - 0 and 1 are polymorphic constants, which are defined on any
  2576   numeric type (nat, int, real etc.);
  2577 
  2578   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2579   binary representation internally;
  2580 
  2581   - type nat has special constructor Suc, and generally prefers Suc 0
  2582   over 1::nat and Suc (Suc 0) over 2::nat;
  2583 
  2584 This change may cause significant problems of INCOMPATIBILITY; here
  2585 are some hints on converting existing sources:
  2586 
  2587   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2588   entities, so expressions involving "-" (unary or binary minus) need
  2589   to be spaced properly;
  2590 
  2591   - existing occurrences of "1" may need to be constraint "1::nat" or
  2592   even replaced by Suc 0; similar for old "2";
  2593 
  2594   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2595 
  2596   - remove all special provisions on numerals in proofs;
  2597 
  2598 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2599 representation (depends on bin_arith_simps in the default context);
  2600 
  2601 * HOL: symbolic syntax for x^2 (numeral 2);
  2602 
  2603 * HOL: the class of all HOL types is now called "type" rather than
  2604 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2605 in axclass/classes, instance/arities, and (usually rare) occurrences
  2606 in typings (of consts etc.); internally the class is called
  2607 "HOL.type", ML programs should refer to HOLogic.typeS;
  2608 
  2609 * HOL/record package improvements:
  2610   - new derived operations "fields" to build a partial record section,
  2611     "extend" to promote a fixed record to a record scheme, and
  2612     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2613     declared as simp by default;
  2614   - shared operations ("more", "fields", etc.) now need to be always
  2615     qualified) --- potential INCOMPATIBILITY;
  2616   - removed "make_scheme" operations (use "make" with "extend") --
  2617     INCOMPATIBILITY;
  2618   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2619   - provides cases/induct rules for use with corresponding Isar
  2620     methods (for concrete records, record schemes, concrete more
  2621     parts, and schematic more parts -- in that order);
  2622   - internal definitions directly based on a light-weight abstract
  2623     theory of product types over typedef rather than datatype;
  2624 
  2625 * HOL: generic code generator for generating executable ML code from
  2626 specifications; specific support for HOL constructs such as inductive
  2627 datatypes and sets, as well as recursive functions; can be invoked
  2628 via 'generate_code' theory section;
  2629 
  2630 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2631 
  2632 * HOL: consolidated and renamed several theories.  In particular:
  2633         Ord.thy has been absorbed into HOL.thy
  2634         String.thy has been absorbed into List.thy
  2635 
  2636 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2637 (beware of argument permutation!);
  2638 
  2639 * HOL: linorder_less_split superseded by linorder_cases;
  2640 
  2641 * HOL/List: "nodups" renamed to "distinct";
  2642 
  2643 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2644 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2645   - Ex_def has changed, now need to use some_eq_ex
  2646 
  2647 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2648 in this (rare) case use:
  2649 
  2650   delSWrapper "split_all_tac"
  2651   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2652 
  2653 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2654 MAY FAIL;
  2655 
  2656 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2657 Isabelle's type classes, ^ on functions and relations has too general
  2658 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2659 necessary to attach explicit type constraints;
  2660 
  2661 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2662 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2663 renamed accordingly (eg "compI" -> "rel_compI").
  2664 
  2665 * HOL: syntax translations now work properly with numerals and records
  2666 expressions;
  2667 
  2668 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2669 of "lam" -- INCOMPATIBILITY;
  2670 
  2671 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2672 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2673 renamed "Product_Type.unit";
  2674 
  2675 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2676 
  2677 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2678 the "cases" method);
  2679 
  2680 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2681 Florian Kammller);
  2682 
  2683 * HOL/IMP: updated and converted to new-style theory format; several
  2684 parts turned into readable document, with proper Isar proof texts and
  2685 some explanations (by Gerwin Klein);
  2686 
  2687 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2688 
  2689 * HOL-Hyperreal is now a logic image;
  2690 
  2691 
  2692 *** HOLCF ***
  2693 
  2694 * Isar: consts/constdefs supports mixfix syntax for continuous
  2695 operations;
  2696 
  2697 * Isar: domain package adapted to new-style theory format, e.g. see
  2698 HOLCF/ex/Dnat.thy;
  2699 
  2700 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2701 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2702 lift.induct_tac, always use UU instead of Undef;
  2703 
  2704 * HOLCF/IMP: updated and converted to new-style theory;
  2705 
  2706 
  2707 *** ZF ***
  2708 
  2709 * Isar: proper integration of logic-specific tools and packages,
  2710 including theory commands '(co)inductive', '(co)datatype',
  2711 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2712 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2713 
  2714 * theory Main no longer includes AC; for the Axiom of Choice, base
  2715 your theory on Main_ZFC;
  2716 
  2717 * the integer library now covers quotients and remainders, with many
  2718 laws relating division to addition, multiplication, etc.;
  2719 
  2720 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2721 typeless version of the formalism;
  2722 
  2723 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2724 format;
  2725 
  2726 * ZF/Induct: new directory for examples of inductive definitions,
  2727 including theory Multiset for multiset orderings; converted to
  2728 new-style theory format;
  2729 
  2730 * ZF: many new theorems about lists, ordinals, etc.;
  2731 
  2732 
  2733 *** General ***
  2734 
  2735 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2736 variable proof controls level of detail: 0 = no proofs (only oracle
  2737 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2738 also ref manual for further ML interfaces;
  2739 
  2740 * Pure/axclass: removed obsolete ML interface
  2741 goal_subclass/goal_arity;
  2742 
  2743 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2744 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2745 separate tokens, so expressions involving minus need to be spaced
  2746 properly;
  2747 
  2748 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2749 rather than "infixl" or "infixr";
  2750 
  2751 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2752 sort constraint specifications in type inference; e.g. "x::_::foo"
  2753 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2754 type variable);
  2755 
  2756 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2757 control output of nested => (types); the default behavior is
  2758 "type_brackets";
  2759 
  2760 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2761 tokens into AST constants;
  2762 
  2763 * Pure/syntax: prefer later declarations of translations and print
  2764 translation functions; potential INCOMPATIBILITY: need to reverse
  2765 multiple declarations for same syntax element constant;
  2766 
  2767 * Pure/show_hyps reset by default (in accordance to existing Isar
  2768 practice);
  2769 
  2770 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2771 addSafter;
  2772 
  2773 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2774 as well;
  2775 
  2776 * system: tested support for MacOS X; should be able to get Isabelle +
  2777 Proof General to work in a plain Terminal after installing Poly/ML
  2778 (e.g. from the Isabelle distribution area) and GNU bash alone
  2779 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2780 support requires further installations, e.g. from
  2781 http://fink.sourceforge.net/);
  2782 
  2783 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2784 
  2785 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2786 of 40 MB), cf. ML_OPTIONS;
  2787 
  2788 * system: Proof General keywords specification is now part of the
  2789 Isabelle distribution (see etc/isar-keywords.el);
  2790 
  2791 * system: support for persistent Proof General sessions (refrain from
  2792 outdating all loaded theories on startup); user may create writable
  2793 logic images like this: ``isabelle -q HOL Test'';
  2794 
  2795 * system: smart selection of Isabelle process versus Isabelle
  2796 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2797 run both "isabelle" and "Isabelle" even if file names are badly
  2798 damaged (executable inspects the case of the first letter of its own
  2799 name); added separate "isabelle-process" and "isabelle-interface";
  2800 
  2801 * system: refrain from any attempt at filtering input streams; no
  2802 longer support ``8bit'' encoding of old isabelle font, instead proper
  2803 iso-latin characters may now be used; the related isatools
  2804 "symbolinput" and "nonascii" have disappeared as well;
  2805 
  2806 * system: removed old "xterm" interface (the print modes "xterm" and
  2807 "xterm_color" are still available for direct use in a suitable
  2808 terminal);
  2809 
  2810 
  2811 
  2812 New in Isabelle99-2 (February 2001)
  2813 -----------------------------------
  2814 
  2815 *** Overview of INCOMPATIBILITIES ***
  2816 
  2817 * HOL: please note that theories in the Library and elsewhere often use the
  2818 new-style (Isar) format; to refer to their theorems in an ML script you must
  2819 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2820 
  2821 * HOL: inductive package no longer splits induction rule aggressively,
  2822 but only as far as specified by the introductions given; the old
  2823 format may be recovered via ML function complete_split_rule or attribute
  2824 'split_rule (complete)';
  2825 
  2826 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2827 gfp_Tarski to gfp_unfold;
  2828 
  2829 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2830 
  2831 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2832 relation); infix "^^" has been renamed "``"; infix "``" has been
  2833 renamed "`"; "univalent" has been renamed "single_valued";
  2834 
  2835 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2836 operation;
  2837 
  2838 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2839 
  2840 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2841 
  2842 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2843 consequence, it is no longer monotonic wrt. the local goal context
  2844 (which is now passed through the inductive cases);
  2845 
  2846 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2847 \<gg> to \<ggreater>;
  2848 
  2849 
  2850 *** Document preparation ***
  2851 
  2852 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2853 available: are "it" for near math-mode best-style output, "sl" for
  2854 slanted text style, and "tt" for plain type-writer; if no
  2855 \isabellestyle command is given, output is according to slanted
  2856 type-writer);
  2857 
  2858 * support sub/super scripts (for single symbols only), input syntax is
  2859 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2860 
  2861 * some more standard symbols; see Appendix A of the system manual for
  2862 the complete list of symbols defined in isabellesym.sty;
  2863 
  2864 * improved isabelle style files; more abstract symbol implementation
  2865 (should now use \isamath{...} and \isatext{...} in custom symbol
  2866 definitions);
  2867 
  2868 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2869 state; Note that presentation of goal states does not conform to
  2870 actual human-readable proof documents.  Please do not include goal
  2871 states into document output unless you really know what you are doing!
  2872 
  2873 * proper indentation of antiquoted output with proportional LaTeX
  2874 fonts;
  2875 
  2876 * no_document ML operator temporarily disables LaTeX document
  2877 generation;
  2878 
  2879 * isatool unsymbolize tunes sources for plain ASCII communication;
  2880 
  2881 
  2882 *** Isar ***
  2883 
  2884 * Pure: Isar now suffers initial goal statements to contain unbound
  2885 schematic variables (this does not conform to actual readable proof
  2886 documents, due to unpredictable outcome and non-compositional proof
  2887 checking); users who know what they are doing may use schematic goals
  2888 for Prolog-style synthesis of proven results;
  2889 
  2890 * Pure: assumption method (an implicit finishing) now handles actual
  2891 rules as well;
  2892 
  2893 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2894 initial goal, declare "that" only as Pure intro (only for single
  2895 steps); the "that" rule assumption may now be involved in implicit
  2896 finishing, thus ".." becomes a feasible for trivial obtains;
  2897 
  2898 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2899 instance proofs may be performed by "..";
  2900 
  2901 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2902 statements as well;
  2903 
  2904 * Pure: more robust selection of calculational rules;
  2905 
  2906 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2907 rule (as well as the assumption rule);
  2908 
  2909 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2910 lemmas, using the graph browser tool;
  2911 
  2912 * Pure: predict failure of "show" in interactive mode;
  2913 
  2914 * Pure: 'thms_containing' now takes actual terms as arguments;
  2915 
  2916 * HOL: improved method 'induct' --- now handles non-atomic goals
  2917 (potential INCOMPATIBILITY); tuned error handling;
  2918 
  2919 * HOL: cases and induct rules now provide explicit hints about the
  2920 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2921 any remaining facts are inserted into the goal verbatim;
  2922 
  2923 * HOL: local contexts (aka cases) may now contain term bindings as
  2924 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2925 the result to be shown in each case;
  2926 
  2927 * HOL: added 'recdef_tc' command;
  2928 
  2929 * isatool convert assists in eliminating legacy ML scripts;
  2930 
  2931 
  2932 *** HOL ***
  2933 
  2934 * HOL/Library: a collection of generic theories to be used together
  2935 with main HOL; the theory loader path already includes this directory
  2936 by default; the following existing theories have been moved here:
  2937 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2938 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2939 
  2940 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2941 modelling and verification task performed in Isabelle/HOL +
  2942 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2943 
  2944 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2945 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2946 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2947 'domain', this makes the theory consistent with mathematical
  2948 literature;
  2949 
  2950 * HOL basics: added overloaded operations "inverse" and "divide"
  2951 (infix "/"), syntax for generic "abs" operation, generic summation
  2952 operator \<Sum>;
  2953 
  2954 * HOL/typedef: simplified package, provide more useful rules (see also
  2955 HOL/subset.thy);
  2956 
  2957 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2958 now expressed as a proper nested rule (old-style tactic scripts may
  2959 require atomize_strip_tac to cope with non-atomic premises);
  2960 
  2961 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2962 to "split_conv" (old name still available for compatibility);
  2963 
  2964 * HOL: improved concrete syntax for strings (e.g. allows translation
  2965 rules with string literals);
  2966 
  2967 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2968  and Fleuriot's mechanization of analysis, including the transcendental
  2969  functions for the reals;
  2970 
  2971 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2972 
  2973 
  2974 *** CTT ***
  2975 
  2976 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2977 "lam" is displayed as TWO lambda-symbols
  2978 
  2979 * CTT: theory Main now available, containing everything (that is, Bool
  2980 and Arith);
  2981 
  2982 
  2983 *** General ***
  2984 
  2985 * Pure: the Simplifier has been implemented properly as a derived rule
  2986 outside of the actual kernel (at last!); the overall performance
  2987 penalty in practical applications is about 50%, while reliability of
  2988 the Isabelle inference kernel has been greatly improved;
  2989 
  2990 * print modes "brackets" and "no_brackets" control output of nested =>
  2991 (types) and ==> (props); the default behaviour is "brackets";
  2992 
  2993 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2994 as assumptions as well;
  2995 
  2996 * system: support Poly/ML 4.0;
  2997 
  2998 * system: isatool install handles KDE version 1 or 2;
  2999 
  3000 
  3001 
  3002 New in Isabelle99-1 (October 2000)
  3003 ----------------------------------
  3004 
  3005 *** Overview of INCOMPATIBILITIES ***
  3006 
  3007 * HOL: simplification of natural numbers is much changed; to partly
  3008 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3009 issue the following ML commands:
  3010 
  3011   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3012   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3013 
  3014 * HOL: simplification no longer dives into case-expressions; this is
  3015 controlled by "t.weak_case_cong" for each datatype t;
  3016 
  3017 * HOL: nat_less_induct renamed to less_induct;
  3018 
  3019 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3020 fixsome to patch .thy and .ML sources automatically;
  3021 
  3022   select_equality  -> some_equality
  3023   select_eq_Ex     -> some_eq_ex
  3024   selectI2EX       -> someI2_ex
  3025   selectI2         -> someI2
  3026   selectI          -> someI
  3027   select1_equality -> some1_equality
  3028   Eps_sym_eq       -> some_sym_eq_trivial
  3029   Eps_eq           -> some_eq_trivial
  3030 
  3031 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3032 
  3033 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3034 instead);
  3035 
  3036 * HOL: the recursion equations generated by 'recdef' are now called
  3037 f.simps instead of f.rules;
  3038 
  3039 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3040 
  3041 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3042 sometimes be needed;
  3043 
  3044 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3045 
  3046 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3047 
  3048 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3049 product is now "<*>" instead of "Times"; the lexicographic product is
  3050 now "<*lex*>" instead of "**";
  3051 
  3052 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3053 of main HOL, but was unused); better use HOL's datatype package;
  3054 
  3055 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3056 the old syntax may be recovered as follows:
  3057 
  3058   syntax (symbols)
  3059     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3060       (infixl "\\<oplus>" 100)
  3061 
  3062 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3063 
  3064 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3065 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3066 internally;
  3067 
  3068 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3069 changed from A/r to A//r;
  3070 
  3071 * ZF: new treatment of arithmetic (nat & int) may break some old
  3072 proofs;
  3073 
  3074 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3075 rulify -> rule_format, elimify -> elim_format, ...);
  3076 
  3077 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3078 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3079 should have to change intro!! to intro? only); replaced "delrule" by
  3080 "rule del";
  3081 
  3082 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3083 
  3084 * Provers: strengthened force_tac by using new first_best_tac;
  3085 
  3086 * LaTeX document preparation: several changes of isabelle.sty (see
  3087 lib/texinputs);
  3088 
  3089 
  3090 *** Document preparation ***
  3091 
  3092 * formal comments (text blocks etc.) in new-style theories may now
  3093 contain antiquotations of thm/prop/term/typ/text to be presented
  3094 according to latex print mode; concrete syntax is like this:
  3095 @{term[show_types] "f(x) = a + x"};
  3096 
  3097 * isatool mkdir provides easy setup of Isabelle session directories,
  3098 including proper document sources;
  3099 
  3100 * generated LaTeX sources are now deleted after successful run
  3101 (isatool document -c); may retain a copy somewhere else via -D option
  3102 of isatool usedir;
  3103 
  3104 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3105 style files, achieving self-contained LaTeX sources and simplifying
  3106 LaTeX debugging;
  3107 
  3108 * old-style theories now produce (crude) LaTeX output as well;
  3109 
  3110 * browser info session directories are now self-contained (may be put
  3111 on WWW server seperately); improved graphs of nested sessions; removed
  3112 graph for 'all sessions';
  3113 
  3114 * several improvements in isabelle style files; \isabellestyle{it}
  3115 produces fake math mode output; \isamarkupheader is now \section by
  3116 default; see lib/texinputs/isabelle.sty etc.;
  3117 
  3118 
  3119 *** Isar ***
  3120 
  3121 * Isar/Pure: local results and corresponding term bindings are now
  3122 subject to Hindley-Milner polymorphism (similar to ML); this
  3123 accommodates incremental type-inference very nicely;
  3124 
  3125 * Isar/Pure: new derived language element 'obtain' supports
  3126 generalized existence reasoning;
  3127 
  3128 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3129 support accumulation of results, without applying any rules yet;
  3130 useful to collect intermediate results without explicit name
  3131 references, and for use with transitivity rules with more than 2
  3132 premises;
  3133 
  3134 * Isar/Pure: scalable support for case-analysis type proofs: new
  3135 'case' language element refers to local contexts symbolically, as
  3136 produced by certain proof methods; internally, case names are attached
  3137 to theorems as "tags";
  3138 
  3139 * Isar/Pure: theory command 'hide' removes declarations from
  3140 class/type/const name spaces;
  3141 
  3142 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3143 indicate potential overloading;
  3144 
  3145 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3146 
  3147 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3148 "{a,b,c}" instead of {a,b,c};
  3149 
  3150 * Isar/Pure now provides its own version of intro/elim/dest
  3151 attributes; useful for building new logics, but beware of confusion
  3152 with the version in Provers/classical;
  3153 
  3154 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3155 case name 'antecedent';
  3156 
  3157 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3158 to the current context is now done automatically);
  3159 
  3160 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3161 for definining proof methods in ML;
  3162 
  3163 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3164 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3165 most cases, one should have to change intro!! to intro? only);
  3166 replaced "delrule" by "rule del";
  3167 
  3168 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3169 'symmetric' attribute (the latter supercedes [RS sym]);
  3170 
  3171 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3172 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3173 well (including splits);
  3174 
  3175 * Isar/Provers: Simplifier and Classical methods now support all kind
  3176 of modifiers used in the past, including 'cong', 'iff', etc.
  3177 
  3178 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3179 of Simplifier and Classical reasoner);
  3180 
  3181 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3182 now support named cases; major packages (inductive, datatype, primrec,
  3183 recdef) support case names and properly name parameters;
  3184 
  3185 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3186 monotonicity conditions are extracted to be proven at end of
  3187 calculations;
  3188 
  3189 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3190 method anyway;
  3191 
  3192 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3193 split_if split_if_asm; datatype package provides theorems foo.splits =
  3194 foo.split foo.split_asm for each datatype;
  3195 
  3196 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3197 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3198 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3199 use "(cases (simplified))" method in proper proof texts);
  3200 
  3201 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3202 
  3203 * Isar: names of theorems etc. may be natural numbers as well;
  3204 
  3205 * Isar: 'pr' command: optional arguments for goals_limit and
  3206 ProofContext.prems_limit; no longer prints theory contexts, but only
  3207 proof states;
  3208 
  3209 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3210 additional print modes to be specified; e.g. "pr(latex)" will print
  3211 proof state according to the Isabelle LaTeX style;
  3212 
  3213 * Isar: improved support for emulating tactic scripts, including proof
  3214 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3215 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3216 (for HOL datatypes);
  3217 
  3218 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3219 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3220 'proof method scripts' have to be in depth-first order;
  3221 
  3222 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3223 
  3224 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3225 should instead use individual commands for printing items
  3226 (print_commands, print_methods etc.);
  3227 
  3228 * Isar: added 'nothing' --- the empty list of theorems;
  3229 
  3230 
  3231 *** HOL ***
  3232 
  3233 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3234 corresponding virtual machine and a specification of its bytecode
  3235 verifier and a lightweight bytecode verifier, including proofs of
  3236 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3237 Cornelia Pusch (see also the homepage of project Bali at
  3238 http://isabelle.in.tum.de/Bali/);
  3239 
  3240 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3241 Clemens Ballarin;
  3242 
  3243 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3244 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3245 Rasmussen;
  3246 
  3247 * HOL/Lattice: fundamental concepts of lattice theory and order
  3248 structures, including duals, properties of bounds versus algebraic
  3249 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3250 Theorem for complete lattices etc.; may also serve as a demonstration
  3251 for abstract algebraic reasoning using axiomatic type classes, and
  3252 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3253 
  3254 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3255 von Oheimb;
  3256 
  3257 * HOL/IMPP: extension of IMP with local variables and mutually
  3258 recursive procedures, by David von Oheimb;
  3259 
  3260 * HOL/Lambda: converted into new-style theory and document;
  3261 
  3262 * HOL/ex/Multiquote: example of multiple nested quotations and
  3263 anti-quotations -- basically a generalized version of de-Bruijn
  3264 representation; very useful in avoiding lifting of operations;
  3265 
  3266 * HOL/record: added general record equality rule to simpset; fixed
  3267 select-update simplification procedure to handle extended records as
  3268 well; admit "r" as field name;
  3269 
  3270 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3271 other numeric types and also as the identity of groups, rings, etc.;
  3272 
  3273 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3274 Types nat and int belong to this axclass;
  3275 
  3276 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3277    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3278    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3279   two terms #m*u and #n*u are replaced by #(m+n)*u
  3280     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3281   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3282     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3283 
  3284 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3285 powerful prover for predicate logic but knows nothing of clasets; see
  3286 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3287 
  3288 * HOL: new version of "case_tac" subsumes both boolean case split and
  3289 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3290 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3291 
  3292 * HOL: simplification no longer dives into case-expressions: only the
  3293 selector expression is simplified, but not the remaining arms; to
  3294 enable full simplification of case-expressions for datatype t, you may
  3295 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3296 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3297 
  3298 * HOL/recdef: the recursion equations generated by 'recdef' for
  3299 function 'f' are now called f.simps instead of f.rules; if all
  3300 termination conditions are proved automatically, these simplification
  3301 rules are added to the simpset, as in primrec; rules may be named
  3302 individually as well, resulting in a separate list of theorems for
  3303 each equation;
  3304 
  3305 * HOL/While is a new theory that provides a while-combinator. It
  3306 permits the definition of tail-recursive functions without the
  3307 provision of a termination measure. The latter is necessary once the
  3308 invariant proof rule for while is applied.
  3309 
  3310 * HOL: new (overloaded) notation for the set of elements below/above
  3311 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3312 
  3313 * HOL: theorems impI, allI, ballI bound as "strip";
  3314 
  3315 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3316 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3317 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3318 
  3319 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3320 
  3321 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3322 main HOL, but was unused);
  3323 
  3324 * HOL: fewer consts declared as global (e.g. have to refer to
  3325 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3326 
  3327 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3328 in case of overlap with user translations (e.g. judgements over
  3329 tuples); (note that the underlying logical represenation is still
  3330 bogus);
  3331 
  3332 
  3333 *** ZF ***
  3334 
  3335 * ZF: simplification automatically cancels common terms in arithmetic
  3336 expressions over nat and int;
  3337 
  3338 * ZF: new treatment of nat to minimize type-checking: all operators
  3339 coerce their operands to a natural number using the function natify,
  3340 making the algebraic laws unconditional;
  3341 
  3342 * ZF: as above, for int: operators coerce their operands to an integer
  3343 using the function intify;
  3344 
  3345 * ZF: the integer library now contains many of the usual laws for the
  3346 orderings, including $<=, and monotonicity laws for $+ and $*;
  3347 
  3348 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3349 simplification;
  3350 
  3351 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3352 to the simplifier and classical reasoner simultaneously;
  3353 
  3354 
  3355 *** General ***
  3356 
  3357 * Provers: blast_tac now handles actual object-logic rules as
  3358 assumptions; note that auto_tac uses blast_tac internally as well;
  3359 
  3360 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3361 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3362 
  3363 * Provers: delrules now handles destruct rules as well (no longer need
  3364 explicit make_elim);
  3365 
  3366 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3367   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3368 use instead the strong form,
  3369   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3370 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3371 from destruct-rules;
  3372 
  3373 * Provers: Simplifier.easy_setup provides a fast path to basic
  3374 Simplifier setup for new object-logics;
  3375 
  3376 * Pure: AST translation rules no longer require constant head on LHS;
  3377 
  3378 * Pure: improved name spaces: ambiguous output is qualified; support
  3379 for hiding of names;
  3380 
  3381 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3382 XSYMBOL_HOME; no longer need to do manual configuration in most
  3383 situations;
  3384 
  3385 * system: compression of ML heaps images may now be controlled via -c
  3386 option of isabelle and isatool usedir (currently only observed by
  3387 Poly/ML);
  3388 
  3389 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3390 useful for remote X11);
  3391 
  3392 * system: provide TAGS file for Isabelle sources;
  3393 
  3394 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3395 order;
  3396 
  3397 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3398 timing flag supersedes proof_timing and Toplevel.trace;
  3399 
  3400 * ML: new combinators |>> and |>>> for incremental transformations
  3401 with secondary results (e.g. certain theory extensions):
  3402 
  3403 * ML: PureThy.add_defs gets additional argument to indicate potential
  3404 overloading (usually false);
  3405 
  3406 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3407 results;
  3408 
  3409 
  3410 
  3411 New in Isabelle99 (October 1999)
  3412 --------------------------------
  3413 
  3414 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3415 
  3416 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3417 are no longer simplified.  (This allows the simplifier to unfold recursive
  3418 functional programs.)  To restore the old behaviour, declare
  3419 
  3420     Delcongs [if_weak_cong];
  3421 
  3422 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3423 complement;
  3424 
  3425 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3426 
  3427 * HOL/datatype: mutual_induct_tac no longer exists --
  3428   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3429 
  3430 * HOL/typedef: fixed type inference for representing set; type
  3431 arguments now have to occur explicitly on the rhs as type constraints;
  3432 
  3433 * ZF: The con_defs part of an inductive definition may no longer refer
  3434 to constants declared in the same theory;
  3435 
  3436 * HOL, ZF: the function mk_cases, generated by the inductive
  3437 definition package, has lost an argument.  To simplify its result, it
  3438 uses the default simpset instead of a supplied list of theorems.
  3439 
  3440 * HOL/List: the constructors of type list are now Nil and Cons;
  3441 
  3442 * Simplifier: the type of the infix ML functions
  3443         setSSolver addSSolver setSolver addSolver
  3444 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3445 for packaging solvers. A solver is created via
  3446         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3447 where the string argument is only a comment.
  3448 
  3449 
  3450 *** Proof tools ***
  3451 
  3452 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3453 decision procedure for linear arithmetic. Currently it is used for
  3454 types `nat', `int', and `real' in HOL (see below); it can, should and
  3455 will be instantiated for other types and logics as well.
  3456 
  3457 * The simplifier now accepts rewrite rules with flexible heads, eg
  3458      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3459   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3460   matching.
  3461 
  3462 
  3463 *** General ***
  3464 
  3465 * New Isabelle/Isar subsystem provides an alternative to traditional
  3466 tactical theorem proving; together with the ProofGeneral/isar user
  3467 interface it offers an interactive environment for developing human
  3468 readable proof documents (Isar == Intelligible semi-automated
  3469 reasoning); for further information see isatool doc isar-ref,
  3470 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3471 
  3472 * improved and simplified presentation of theories: better HTML markup
  3473 (including colors), graph views in several sizes; isatool usedir now
  3474 provides a proper interface for user theories (via -P option); actual
  3475 document preparation based on (PDF)LaTeX is available as well (for
  3476 new-style theories only); see isatool doc system for more information;
  3477 
  3478 * native support for Proof General, both for classic Isabelle and
  3479 Isabelle/Isar;
  3480 
  3481 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3482 using the graph browser tool;
  3483 
  3484 * Isabelle manuals now also available as PDF;
  3485 
  3486 * theory loader rewritten from scratch (may not be fully
  3487 bug-compatible); old loadpath variable has been replaced by show_path,
  3488 add_path, del_path, reset_path functions; new operations such as
  3489 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3490 isatool doc ref);
  3491 
  3492 * improved isatool install: option -k creates KDE application icon,
  3493 option -p DIR installs standalone binaries;
  3494 
  3495 * added ML_PLATFORM setting (useful for cross-platform installations);
  3496 more robust handling of platform specific ML images for SML/NJ;
  3497 
  3498 * the settings environment is now statically scoped, i.e. it is never
  3499 created again in sub-processes invoked from isabelle, isatool, or
  3500 Isabelle;
  3501 
  3502 * path element specification '~~' refers to '$ISABELLE_HOME';
  3503 
  3504 * in locales, the "assumes" and "defines" parts may be omitted if
  3505 empty;
  3506 
  3507 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3508 long arrows);
  3509 
  3510 * new print_mode "HTML";
  3511 
  3512 * new flag show_tags controls display of tags of theorems (which are
  3513 basically just comments that may be attached by some tools);
  3514 
  3515 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3516 mode and goal output format:
  3517 
  3518 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3519 244c244
  3520 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3521 ---
  3522 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3523 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3524 181c181
  3525 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3526 ---
  3527 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3528 
  3529 * function bind_thms stores lists of theorems (cf. bind_thm);
  3530 
  3531 * new shorthand tactics ftac, eatac, datac, fatac;
  3532 
  3533 * qed (and friends) now accept "" as result name; in that case the
  3534 theorem is not stored, but proper checks and presentation of the
  3535 result still apply;
  3536 
  3537 * theorem database now also indexes constants "Trueprop", "all",
  3538 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3539 
  3540 
  3541 *** HOL ***
  3542 
  3543 ** HOL arithmetic **
  3544 
  3545 * There are now decision procedures for linear arithmetic over nat and
  3546 int:
  3547 
  3548 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3549 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3550 are treated as atomic; subformulae not involving type `nat' or `int'
  3551 are ignored; quantified subformulae are ignored unless they are
  3552 positive universal or negative existential. The tactic has to be
  3553 invoked by hand and can be a little bit slow. In particular, the
  3554 running time is exponential in the number of occurrences of `min' and
  3555 `max', and `-' on `nat'.
  3556 
  3557 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3558 (negated) (in)equalities among the premises and the conclusion into
  3559 account (i.e. no compound formulae) and does not know about `min' and
  3560 `max', and `-' on `nat'. It is fast and is used automatically by the
  3561 simplifier.
  3562 
  3563 NB: At the moment, these decision procedures do not cope with mixed
  3564 nat/int formulae where the two parts interact, such as `m < n ==>
  3565 int(m) < int(n)'.
  3566 
  3567 * HOL/Numeral provides a generic theory of numerals (encoded
  3568 efficiently as bit strings); setup for types nat/int/real is in place;
  3569 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3570 int, existing theories and proof scripts may require a few additional
  3571 type constraints;
  3572 
  3573 * integer division and remainder can now be performed on constant
  3574 arguments;
  3575 
  3576 * many properties of integer multiplication, division and remainder
  3577 are now available;
  3578 
  3579 * An interface to the Stanford Validity Checker (SVC) is available through the
  3580 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3581 are proved automatically.  SVC must be installed separately, and its results
  3582 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3583 invocation of the underlying oracle).  For SVC see
  3584   http://verify.stanford.edu/SVC
  3585 
  3586 * IsaMakefile: the HOL-Real target now builds an actual image;
  3587 
  3588 
  3589 ** HOL misc **
  3590 
  3591 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3592 (in Isabelle/Isar) -- by Gertrud Bauer;
  3593 
  3594 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3595 analysis for assembly languages with subtypes;
  3596 
  3597 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3598 -- avoids syntactic ambiguities and treats state, transition, and
  3599 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3600 changed syntax and (many) tactics;
  3601 
  3602 * HOL/inductive: Now also handles more general introduction rules such
  3603   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3604   theorems are now maintained within the theory (maintained via the
  3605   "mono" attribute);
  3606 
  3607 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3608   (using function types) such as
  3609 
  3610   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3611 
  3612 * HOL/record: record_simproc (part of the default simpset) takes care
  3613 of selectors applied to updated records; record_split_tac is no longer
  3614 part of the default claset; update_defs may now be removed from the
  3615 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3616 
  3617   claset_ref () := claset() addSWrapper record_split_wrapper;
  3618   Delsimprocs [record_simproc]
  3619 
  3620 * HOL/typedef: fixed type inference for representing set; type
  3621 arguments now have to occur explicitly on the rhs as type constraints;
  3622 
  3623 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3624 names rather than an ML expression;
  3625 
  3626 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3627 supplied later.  Program schemes can be defined, such as
  3628     "While B C s = (if B s then While B C (C s) else s)"
  3629 where the well-founded relation can be chosen after B and C have been given.
  3630 
  3631 * HOL/List: the constructors of type list are now Nil and Cons;
  3632 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3633 course, ML tools referring to List.list.op # etc. have to be adapted;
  3634 
  3635 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3636 disabled by default; run isabelle with option -m HOL to get back to
  3637 the original Gordon/HOL-style output;
  3638 
  3639 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3640 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3641 
  3642 * HOL basic syntax simplified (more orthogonal): all variants of
  3643 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3644 Eps operator is provided as well: "SOME x. P[x]";
  3645 
  3646 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3647 
  3648 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3649 thus available for user theories;
  3650 
  3651 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3652 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3653 time;
  3654 
  3655 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3656 several times and then mp;
  3657 
  3658 
  3659 *** LK ***
  3660 
  3661 * the notation <<...>> is now available as a notation for sequences of
  3662 formulas;
  3663 
  3664 * the simplifier is now installed
  3665 
  3666 * the axiom system has been generalized (thanks to Soren Heilmann)
  3667 
  3668 * the classical reasoner now has a default rule database
  3669 
  3670 
  3671 *** ZF ***
  3672 
  3673 * new primrec section allows primitive recursive functions to be given
  3674 directly (as in HOL) over datatypes and the natural numbers;
  3675 
  3676 * new tactics induct_tac and exhaust_tac for induction (or case
  3677 analysis) over datatypes and the natural numbers;
  3678 
  3679 * the datatype declaration of type T now defines the recursor T_rec;
  3680 
  3681 * simplification automatically does freeness reasoning for datatype
  3682 constructors;
  3683 
  3684 * automatic type-inference, with AddTCs command to insert new
  3685 type-checking rules;
  3686 
  3687 * datatype introduction rules are now added as Safe Introduction rules
  3688 to the claset;
  3689 
  3690 * the syntax "if P then x else y" is now available in addition to
  3691 if(P,x,y);
  3692 
  3693 
  3694 *** Internal programming interfaces ***
  3695 
  3696 * tuned simplifier trace output; new flag debug_simp;
  3697 
  3698 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3699 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3700 
  3701 * AxClass.axclass_tac lost the theory argument;
  3702 
  3703 * tuned current_goals_markers semantics: begin / end goal avoids
  3704 printing empty lines;
  3705 
  3706 * removed prs and prs_fn hook, which was broken because it did not
  3707 include \n in its semantics, forcing writeln to add one
  3708 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3709 string -> unit if you really want to output text without newline;
  3710 
  3711 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3712 plain output, interface builders may have to enable 'isabelle_font'
  3713 mode to get Isabelle font glyphs as before;
  3714 
  3715 * refined token_translation interface; INCOMPATIBILITY: output length
  3716 now of type real instead of int;
  3717 
  3718 * theory loader actions may be traced via new ThyInfo.add_hook
  3719 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3720 your own database of information attached to *whole* theories -- as
  3721 opposed to intra-theory data slots offered via TheoryDataFun;
  3722 
  3723 * proper handling of dangling sort hypotheses (at last!);
  3724 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3725 extra sort hypotheses that can be witnessed from the type signature;
  3726 the force_strip_shyps flag is gone, any remaining shyps are simply
  3727 left in the theorem (with a warning issued by strip_shyps_warning);
  3728 
  3729 
  3730 
  3731 New in Isabelle98-1 (October 1998)
  3732 ----------------------------------
  3733 
  3734 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3735 
  3736 * several changes of automated proof tools;
  3737 
  3738 * HOL: major changes to the inductive and datatype packages, including
  3739 some minor incompatibilities of theory syntax;
  3740 
  3741 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3742 called `inj_on';
  3743 
  3744 * HOL: removed duplicate thms in Arith:
  3745   less_imp_add_less  should be replaced by  trans_less_add1
  3746   le_imp_add_le      should be replaced by  trans_le_add1
  3747 
  3748 * HOL: unary minus is now overloaded (new type constraints may be
  3749 required);
  3750 
  3751 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3752 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3753 now taken as an integer constant.
  3754 
  3755 * Pure: ML function 'theory_of' renamed to 'theory';
  3756 
  3757 
  3758 *** Proof tools ***
  3759 
  3760 * Simplifier:
  3761   1. Asm_full_simp_tac is now more aggressive.
  3762      1. It will sometimes reorient premises if that increases their power to
  3763         simplify.
  3764      2. It does no longer proceed strictly from left to right but may also
  3765         rotate premises to achieve further simplification.
  3766      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3767      old Asm_full_simp_tac in that it does not rotate premises.
  3768   2. The simplifier now knows a little bit about nat-arithmetic.
  3769 
  3770 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3771 allows for selected deletion of wrappers, by introduction of names for
  3772 wrapper functionals.  This implies that addbefore, addSbefore,
  3773 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3774 and that adding two tactics with the same name overwrites the first
  3775 one (emitting a warning).
  3776   type wrapper = (int -> tactic) -> (int -> tactic)
  3777   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3778   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3779   delWrapper, delSWrapper: claset *  string            -> claset
  3780   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3781 
  3782 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3783 semantics; addbefore now affects only the unsafe part of step_tac
  3784 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3785 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3786 by Force_tac;
  3787 
  3788 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3789 compWrapper; added safe wrapper (and access functions for it);
  3790 
  3791 * HOL/split_all_tac is now much faster and fails if there is nothing
  3792 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3793 and the names of the automatically generated variables have changed.
  3794 split_all_tac has moved within claset() from unsafe wrappers to safe
  3795 wrappers, which means that !!-bound variables are split much more
  3796 aggressively, and safe_tac and clarify_tac now split such variables.
  3797 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3798 Note: the same holds for record_split_tac, which does the job of
  3799 split_all_tac for record fields.
  3800 
  3801 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3802 permanently to the default simpset using Addsplits just like
  3803 Addsimps. They can be removed via Delsplits just like
  3804 Delsimps. Lower-case versions are also available.
  3805 
  3806 * HOL/Simplifier: The rule split_if is now part of the default
  3807 simpset. This means that the simplifier will eliminate all occurrences
  3808 of if-then-else in the conclusion of a goal. To prevent this, you can
  3809 either remove split_if completely from the default simpset by
  3810 `Delsplits [split_if]' or remove it in a specific call of the
  3811 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3812 other case splitting rules to/from the default simpset: every datatype
  3813 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3814 t is the name of the datatype).
  3815 
  3816 * Classical reasoner / Simplifier combination: new force_tac (and
  3817 derivatives Force_tac, force) combines rewriting and classical
  3818 reasoning (and whatever other tools) similarly to auto_tac, but is
  3819 aimed to solve the given subgoal completely.
  3820 
  3821 
  3822 *** General ***
  3823 
  3824 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3825 and `goalw': the theory is no longer needed as an explicit argument -
  3826 the current theory context is used; assumptions are no longer returned
  3827 at the ML-level unless one of them starts with ==> or !!; it is
  3828 recommended to convert to these new commands using isatool fixgoal
  3829 (backup your sources first!);
  3830 
  3831 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3832 the current theory context, and 'theory' to lookup stored theories;
  3833 
  3834 * new theory section 'locale' for declaring constants, assumptions and
  3835 definitions that have local scope;
  3836 
  3837 * new theory section 'nonterminals' for purely syntactic types;
  3838 
  3839 * new theory section 'setup' for generic ML setup functions
  3840 (e.g. package initialization);
  3841 
  3842 * the distribution now includes Isabelle icons: see
  3843 lib/logo/isabelle-{small,tiny}.xpm;
  3844 
  3845 * isatool install - install binaries with absolute references to
  3846 ISABELLE_HOME/bin;
  3847 
  3848 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3849 
  3850 * print mode 'emacs' reserved for Isamode;
  3851 
  3852 * support multiple print (ast) translations per constant name;
  3853 
  3854 * theorems involving oracles are now printed with a suffixed [!];
  3855 
  3856 
  3857 *** HOL ***
  3858 
  3859 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3860 
  3861 * HOL/inductive package reorganized and improved: now supports mutual
  3862 definitions such as
  3863 
  3864   inductive EVEN ODD
  3865     intrs
  3866       null "0 : EVEN"
  3867       oddI "n : EVEN ==> Suc n : ODD"
  3868       evenI "n : ODD ==> Suc n : EVEN"
  3869 
  3870 new theorem list "elims" contains an elimination rule for each of the
  3871 recursive sets; inductive definitions now handle disjunctive premises
  3872 correctly (also ZF);
  3873 
  3874 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3875 "mutual_induct" no longer exists - the induction rule is always
  3876 contained in "induct";
  3877 
  3878 
  3879 * HOL/datatype package re-implemented and greatly improved: now
  3880 supports mutually recursive datatypes such as
  3881 
  3882   datatype
  3883     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3884             | SUM ('a aexp) ('a aexp)
  3885             | DIFF ('a aexp) ('a aexp)
  3886             | NUM 'a
  3887   and
  3888     'a bexp = LESS ('a aexp) ('a aexp)
  3889             | AND ('a bexp) ('a bexp)
  3890             | OR ('a bexp) ('a bexp)
  3891 
  3892 as well as indirectly recursive datatypes such as
  3893 
  3894   datatype
  3895     ('a, 'b) term = Var 'a
  3896                   | App 'b ((('a, 'b) term) list)
  3897 
  3898 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3899 induction on mutually / indirectly recursive datatypes.
  3900 
  3901 Primrec equations are now stored in theory and can be accessed via
  3902 <function_name>.simps.
  3903 
  3904 INCOMPATIBILITIES:
  3905 
  3906   - Theories using datatypes must now have theory Datatype as an
  3907     ancestor.
  3908   - The specific <typename>.induct_tac no longer exists - use the
  3909     generic induct_tac instead.
  3910   - natE has been renamed to nat.exhaust - use exhaust_tac
  3911     instead of res_inst_tac ... natE. Note that the variable
  3912     names in nat.exhaust differ from the names in natE, this
  3913     may cause some "fragile" proofs to fail.
  3914   - The theorems split_<typename>_case and split_<typename>_case_asm
  3915     have been renamed to <typename>.split and <typename>.split_asm.
  3916   - Since default sorts of type variables are now handled correctly,
  3917     some datatype definitions may have to be annotated with explicit
  3918     sort constraints.
  3919   - Primrec definitions no longer require function name and type
  3920     of recursive argument.
  3921 
  3922 Consider using isatool fixdatatype to adapt your theories and proof
  3923 scripts to the new package (backup your sources first!).
  3924 
  3925 
  3926 * HOL/record package: considerably improved implementation; now
  3927 includes concrete syntax for record types, terms, updates; theorems
  3928 for surjective pairing and splitting !!-bound record variables; proof
  3929 support is as follows:
  3930 
  3931   1) standard conversions (selectors or updates applied to record
  3932 constructor terms) are part of the standard simpset;
  3933 
  3934   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3935 made part of standard simpset and claset via addIffs;
  3936 
  3937   3) a tactic for record field splitting (record_split_tac) is part of
  3938 the standard claset (addSWrapper);
  3939 
  3940 To get a better idea about these rules you may retrieve them via
  3941 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3942 the name of your record type.
  3943 
  3944 The split tactic 3) conceptually simplifies by the following rule:
  3945 
  3946   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3947 
  3948 Thus any record variable that is bound by meta-all will automatically
  3949 blow up into some record constructor term, consequently the
  3950 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3951 solve record problems automatically.
  3952 
  3953 
  3954 * reorganized the main HOL image: HOL/Integ and String loaded by
  3955 default; theory Main includes everything;
  3956 
  3957 * automatic simplification of integer sums and comparisons, using cancellation;
  3958 
  3959 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3960 
  3961 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3962 
  3963 * many new identities for unions, intersections, set difference, etc.;
  3964 
  3965 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3966 called split_if, split_split, split_sum_case and split_nat_case (to go
  3967 with add/delsplits);
  3968 
  3969 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3970 (?x::unit) = (); this is made part of the default simpset, which COULD
  3971 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3972 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3973 unit_abs_eta_conv is added in order to counter the effect of
  3974 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3975 %u.f();
  3976 
  3977 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3978 makes more sense);
  3979 
  3980 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3981   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3982   disjointness reasoning but breaking a few old proofs.
  3983 
  3984 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3985 to 'converse' from 'inverse' (for compatibility with ZF and some
  3986 literature);
  3987 
  3988 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3989 the well-founded relation;
  3990 
  3991 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3992     Compl A.  The "Compl" syntax remains available as input syntax for this
  3993     release ONLY.
  3994 
  3995 * HOL/Update: new theory of function updates:
  3996     f(a:=b) == %x. if x=a then b else f x
  3997 may also be iterated as in f(a:=b,c:=d,...);
  3998 
  3999 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4000 
  4001 * HOL/List:
  4002   - new function list_update written xs[i:=v] that updates the i-th
  4003     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4004   - new function `upt' written [i..j(] which generates the list
  4005     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4006     bound write [i..j], which is a shorthand for [i..j+1(].
  4007   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4008 
  4009 * HOL/Arith:
  4010   - removed 'pred' (predecessor) function;
  4011   - generalized some theorems about n-1;
  4012   - many new laws about "div" and "mod";
  4013   - new laws about greatest common divisors (see theory ex/Primes);
  4014 
  4015 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4016 instead of "inverse";
  4017 
  4018 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4019   of the multiset ordering;
  4020 
  4021 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4022   (not included by default);
  4023 
  4024 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4025 
  4026 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4027   programs, i.e. different program variables may have different types.
  4028 
  4029 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4030   [previously, this check worked only if the rewrite rule was unconditional]
  4031   Now rew can involve either definitions or equalities (either == or =).
  4032 
  4033 
  4034 *** ZF ***
  4035 
  4036 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4037   only the theorems proved on ZF.ML;
  4038 
  4039 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4040   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4041   disjointness reasoning but breaking a few old proofs.
  4042 
  4043 * ZF/Update: new theory of function updates
  4044     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4045   may also be iterated as in f(a:=b,c:=d,...);
  4046 
  4047 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4048 
  4049 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4050   [previously, this check worked only if the rewrite rule was unconditional]
  4051   Now rew can involve either definitions or equalities (either == or =).
  4052 
  4053 * case_tac provided for compatibility with HOL
  4054     (like the old excluded_middle_tac, but with subgoals swapped)
  4055 
  4056 
  4057 *** Internal programming interfaces ***
  4058 
  4059 * Pure: several new basic modules made available for general use, see
  4060 also src/Pure/README;
  4061 
  4062 * improved the theory data mechanism to support encapsulation (data
  4063 kind name replaced by private Object.kind, acting as authorization
  4064 key); new type-safe user interface via functor TheoryDataFun; generic
  4065 print_data function becomes basically useless;
  4066 
  4067 * removed global_names compatibility flag -- all theory declarations
  4068 are qualified by default;
  4069 
  4070 * module Pure/Syntax now offers quote / antiquote translation
  4071 functions (useful for Hoare logic etc. with implicit dependencies);
  4072 see HOL/ex/Antiquote for an example use;
  4073 
  4074 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4075 cterm -> thm;
  4076 
  4077 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4078 subgoal;
  4079 
  4080 * Display.print_goals function moved to Locale.print_goals;
  4081 
  4082 * standard print function for goals supports current_goals_markers
  4083 variable for marking begin of proof, end of proof, start of goal; the
  4084 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4085 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4086 for example;
  4087 
  4088 
  4089 
  4090 New in Isabelle98 (January 1998)
  4091 --------------------------------
  4092 
  4093 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4094 
  4095 * changed lexical syntax of terms / types: dots made part of long
  4096 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4097 
  4098 * simpset (and claset) reference variable replaced by functions
  4099 simpset / simpset_ref;
  4100 
  4101 * no longer supports theory aliases (via merge) and non-trivial
  4102 implicit merge of thms' signatures;
  4103 
  4104 * most internal names of constants changed due to qualified names;
  4105 
  4106 * changed Pure/Sequence interface (see Pure/seq.ML);
  4107 
  4108 
  4109 *** General Changes ***
  4110 
  4111 * hierachically structured name spaces (for consts, types, axms, thms
  4112 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4113 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4114 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4115 long_names for fully qualified output names; NOTE: ML programs
  4116 (special tactics, packages etc.) referring to internal names may have
  4117 to be adapted to cope with fully qualified names; in case of severe
  4118 backward campatibility problems try setting 'global_names' at compile
  4119 time to have enrything declared within a flat name space; one may also
  4120 fine tune name declarations in theories via the 'global' and 'local'
  4121 section;
  4122 
  4123 * reimplemented the implicit simpset and claset using the new anytype
  4124 data filed in signatures; references simpset:simpset ref etc. are
  4125 replaced by functions simpset:unit->simpset and
  4126 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4127 to patch your ML files accordingly;
  4128 
  4129 * HTML output now includes theory graph data for display with Java
  4130 applet or isatool browser; data generated automatically via isatool
  4131 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4132 
  4133 * defs may now be conditional; improved rewrite_goals_tac to handle
  4134 conditional equations;
  4135 
  4136 * defs now admits additional type arguments, using TYPE('a) syntax;
  4137 
  4138 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4139 creates a new theory node; implicit merge of thms' signatures is
  4140 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4141 transfer:theory->thm->thm in (rare) cases;
  4142 
  4143 * improved handling of draft signatures / theories; draft thms (and
  4144 ctyps, cterms) are automatically promoted to real ones;
  4145 
  4146 * slightly changed interfaces for oracles: admit many per theory, named
  4147 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4148 
  4149 * print_goals: optional output of const types (set show_consts and
  4150 show_types);
  4151 
  4152 * improved output of warnings (###) and errors (***);
  4153 
  4154 * subgoal_tac displays a warning if the new subgoal has type variables;
  4155 
  4156 * removed old README and Makefiles;
  4157 
  4158 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4159 
  4160 * removed obsolete init_pps and init_database;
  4161 
  4162 * deleted the obsolete tactical STATE, which was declared by
  4163     fun STATE tacfun st = tacfun st st;
  4164 
  4165 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4166 (which abbreviates $HOME);
  4167 
  4168 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4169 use isatool fixseq to adapt your ML programs (this works for fully
  4170 qualified references to the Sequence structure only!);
  4171 
  4172 * use_thy no longer requires writable current directory; it always
  4173 reloads .ML *and* .thy file, if either one is out of date;
  4174 
  4175 
  4176 *** Classical Reasoner ***
  4177 
  4178 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4179 tactics that use classical reasoning to simplify a subgoal without
  4180 splitting it into several subgoals;
  4181 
  4182 * Safe_tac: like safe_tac but uses the default claset;
  4183 
  4184 
  4185 *** Simplifier ***
  4186 
  4187 * added simplification meta rules:
  4188     (asm_)(full_)simplify: simpset -> thm -> thm;
  4189 
  4190 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4191 logics (again);
  4192 
  4193 * added prems argument to simplification procedures;
  4194 
  4195 * HOL, FOL, ZF: added infix function `addsplits':
  4196   instead of `<simpset> setloop (split_tac <thms>)'
  4197   you can simply write `<simpset> addsplits <thms>'
  4198 
  4199 
  4200 *** Syntax ***
  4201 
  4202 * TYPE('a) syntax for type reflection terms;
  4203 
  4204 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4205 
  4206 * pretty printer: changed order of mixfix annotation preference (again!);
  4207 
  4208 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4209 
  4210 
  4211 *** HOL ***
  4212 
  4213 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4214   with `addloop' of the simplifier to faciliate case splitting in premises.
  4215 
  4216 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4217 
  4218 * HOL/Auth: new protocol proofs including some for the Internet
  4219   protocol TLS;
  4220 
  4221 * HOL/Map: new theory of `maps' a la VDM;
  4222 
  4223 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4224 cancelling out common nat summands from =, <, <= (in)equalities, or
  4225 differences; simplification procedures nat_cancel_factor for
  4226 cancelling common factor from =, <, <= (in)equalities over natural
  4227 sums; nat_cancel contains both kinds of procedures, it is installed by
  4228 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4229 
  4230 * HOL/simplifier: terms of the form
  4231   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4232   are rewritten to
  4233   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4234   and those of the form
  4235   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4236   are rewritten to
  4237   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4238 
  4239 * HOL/datatype
  4240   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4241 
  4242   P(t_case f1 ... fn x) =
  4243      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4244         ...
  4245        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4246      )
  4247 
  4248   and a theorem `split_t_case_asm' of the form
  4249 
  4250   P(t_case f1 ... fn x) =
  4251     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4252         ...
  4253        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4254      )
  4255   which can be added to a simpset via `addsplits'. The existing theorems
  4256   expand_list_case and expand_option_case have been renamed to
  4257   split_list_case and split_option_case.
  4258 
  4259 * HOL/Arithmetic:
  4260   - `pred n' is automatically converted to `n-1'.
  4261     Users are strongly encouraged not to use `pred' any longer,
  4262     because it will disappear altogether at some point.
  4263   - Users are strongly encouraged to write "0 < n" rather than
  4264     "n ~= 0". Theorems and proof tools have been modified towards this
  4265     `standard'.
  4266 
  4267 * HOL/Lists:
  4268   the function "set_of_list" has been renamed "set" (and its theorems too);
  4269   the function "nth" now takes its arguments in the reverse order and
  4270   has acquired the infix notation "!" as in "xs!n".
  4271 
  4272 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4273 
  4274 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4275   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4276 
  4277 * HOL/record: extensible records with schematic structural subtyping
  4278 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4279 still lacks various theorems and concrete record syntax;
  4280 
  4281 
  4282 *** HOLCF ***
  4283 
  4284 * removed "axioms" and "generated by" sections;
  4285 
  4286 * replaced "ops" section by extended "consts" section, which is capable of
  4287   handling the continuous function space "->" directly;
  4288 
  4289 * domain package:
  4290   . proves theorems immediately and stores them in the theory,
  4291   . creates hierachical name space,
  4292   . now uses normal mixfix annotations (instead of cinfix...),
  4293   . minor changes to some names and values (for consistency),
  4294   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4295   . separator between mutual domain defs: changed "," to "and",
  4296   . improved handling of sort constraints;  now they have to
  4297     appear on the left-hand side of the equations only;
  4298 
  4299 * fixed LAM <x,y,zs>.b syntax;
  4300 
  4301 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4302 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4303 
  4304 
  4305 *** FOL and ZF ***
  4306 
  4307 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4308   with `addloop' of the simplifier to faciliate case splitting in premises.
  4309 
  4310 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4311 in HOL, they strip ALL and --> from proved theorems;
  4312 
  4313 
  4314 
  4315 New in Isabelle94-8 (May 1997)
  4316 ------------------------------
  4317 
  4318 *** General Changes ***
  4319 
  4320 * new utilities to build / run / maintain Isabelle etc. (in parts
  4321 still somewhat experimental); old Makefiles etc. still functional;
  4322 
  4323 * new 'Isabelle System Manual';
  4324 
  4325 * INSTALL text, together with ./configure and ./build scripts;
  4326 
  4327 * reimplemented type inference for greater efficiency, better error
  4328 messages and clean internal interface;
  4329 
  4330 * prlim command for dealing with lots of subgoals (an easier way of
  4331 setting goals_limit);
  4332 
  4333 
  4334 *** Syntax ***
  4335 
  4336 * supports alternative (named) syntax tables (parser and pretty
  4337 printer); internal interface is provided by add_modesyntax(_i);
  4338 
  4339 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4340 be used in conjunction with the Isabelle symbol font; uses the
  4341 "symbols" syntax table;
  4342 
  4343 * added token_translation interface (may translate name tokens in
  4344 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4345 the current print_mode); IMPORTANT: user print translation functions
  4346 are responsible for marking newly introduced bounds
  4347 (Syntax.mark_boundT);
  4348 
  4349 * token translations for modes "xterm" and "xterm_color" that display
  4350 names in bold, underline etc. or colors (which requires a color
  4351 version of xterm);
  4352 
  4353 * infixes may now be declared with names independent of their syntax;
  4354 
  4355 * added typed_print_translation (like print_translation, but may
  4356 access type of constant);
  4357 
  4358 
  4359 *** Classical Reasoner ***
  4360 
  4361 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4362 some limitations.  Blast_tac...
  4363   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4364   + ignores elimination rules that don't have the correct format
  4365         (the conclusion MUST be a formula variable)
  4366   + ignores types, which can make HOL proofs fail
  4367   + rules must not require higher-order unification, e.g. apply_type in ZF
  4368     [message "Function Var's argument not a bound variable" relates to this]
  4369   + its proof strategy is more general but can actually be slower
  4370 
  4371 * substitution with equality assumptions no longer permutes other
  4372 assumptions;
  4373 
  4374 * minor changes in semantics of addafter (now called addaltern); renamed
  4375 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4376 (and access functions for it);
  4377 
  4378 * improved combination of classical reasoner and simplifier:
  4379   + functions for handling clasimpsets
  4380   + improvement of addss: now the simplifier is called _after_ the
  4381     safe steps.
  4382   + safe variant of addss called addSss: uses safe simplifications
  4383     _during_ the safe steps. It is more complete as it allows multiple
  4384     instantiations of unknowns (e.g. with slow_tac).
  4385 
  4386 *** Simplifier ***
  4387 
  4388 * added interface for simplification procedures (functions that
  4389 produce *proven* rewrite rules on the fly, depending on current
  4390 redex);
  4391 
  4392 * ordering on terms as parameter (used for ordered rewriting);
  4393 
  4394 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4395 
  4396 * the solver is now split into a safe and an unsafe part.
  4397 This should be invisible for the normal user, except that the
  4398 functions setsolver and addsolver have been renamed to setSolver and
  4399 addSolver; added safe_asm_full_simp_tac;
  4400 
  4401 
  4402 *** HOL ***
  4403 
  4404 * a generic induction tactic `induct_tac' which works for all datatypes and
  4405 also for type `nat';
  4406 
  4407 * a generic case distinction tactic `exhaust_tac' which works for all
  4408 datatypes and also for type `nat';
  4409 
  4410 * each datatype comes with a function `size';
  4411 
  4412 * patterns in case expressions allow tuple patterns as arguments to
  4413 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4414 
  4415 * primrec now also works with type nat;
  4416 
  4417 * recdef: a new declaration form, allows general recursive functions to be
  4418 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4419 
  4420 * the constant for negation has been renamed from "not" to "Not" to
  4421 harmonize with FOL, ZF, LK, etc.;
  4422 
  4423 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4424 infinite lists;
  4425 
  4426 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4427 
  4428 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4429 problems in commutative rings, using axiomatic type classes for + and *;
  4430 
  4431 * more examples in HOL/MiniML and HOL/Auth;
  4432 
  4433 * more default rewrite rules for quantifiers, union/intersection;
  4434 
  4435 * a new constant `arbitrary == @x.False';
  4436 
  4437 * HOLCF/IOA replaces old HOL/IOA;
  4438 
  4439 * HOLCF changes: derived all rules and arities
  4440   + axiomatic type classes instead of classes
  4441   + typedef instead of faking type definitions
  4442   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4443   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4444   + eliminated the types void, one, tr
  4445   + use unit lift and bool lift (with translations) instead of one and tr
  4446   + eliminated blift from Lift3.thy (use Def instead of blift)
  4447   all eliminated rules are derived as theorems --> no visible changes ;
  4448 
  4449 
  4450 *** ZF ***
  4451 
  4452 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4453 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4454 as ZF_cs addSIs [equalityI];
  4455 
  4456 
  4457 
  4458 New in Isabelle94-7 (November 96)
  4459 ---------------------------------
  4460 
  4461 * allowing negative levels (as offsets) in prlev and choplev;
  4462 
  4463 * super-linear speedup for large simplifications;
  4464 
  4465 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4466 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4467 FAIL); can suppress it using the command Delsimps (ex_simps @
  4468 all_simps); De Morgan laws are also now included, by default;
  4469 
  4470 * improved printing of ==>  :  ~:
  4471 
  4472 * new object-logic "Sequents" adds linear logic, while replacing LK
  4473 and Modal (thanks to Sara Kalvala);
  4474 
  4475 * HOL/Auth: correctness proofs for authentication protocols;
  4476 
  4477 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4478 examples on HOL/Auth);
  4479 
  4480 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4481 the rewriter and classical reasoner simultaneously;
  4482 
  4483 * function uresult no longer returns theorems in "standard" format;
  4484 regain previous version by: val uresult = standard o uresult;
  4485 
  4486 
  4487 
  4488 New in Isabelle94-6
  4489 -------------------
  4490 
  4491 * oracles -- these establish an interface between Isabelle and trusted
  4492 external reasoners, which may deliver results as theorems;
  4493 
  4494 * proof objects (in particular record all uses of oracles);
  4495 
  4496 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4497 
  4498 * "constdefs" section in theory files;
  4499 
  4500 * "primrec" section (HOL) no longer requires names;
  4501 
  4502 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4503 
  4504 
  4505 
  4506 New in Isabelle94-5
  4507 -------------------
  4508 
  4509 * reduced space requirements;
  4510 
  4511 * automatic HTML generation from theories;
  4512 
  4513 * theory files no longer require "..." (quotes) around most types;
  4514 
  4515 * new examples, including two proofs of the Church-Rosser theorem;
  4516 
  4517 * non-curried (1994) version of HOL is no longer distributed;
  4518 
  4519 
  4520 
  4521 New in Isabelle94-4
  4522 -------------------
  4523 
  4524 * greatly reduced space requirements;
  4525 
  4526 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4527 
  4528 * searchable theorem database (see the section "Retrieving theorems" on
  4529 page 8 of the Reference Manual);
  4530 
  4531 * new examples, including Grabczewski's monumental case study of the
  4532 Axiom of Choice;
  4533 
  4534 * The previous version of HOL renamed to Old_HOL;
  4535 
  4536 * The new version of HOL (previously called CHOL) uses a curried syntax
  4537 for functions.  Application looks like f a b instead of f(a,b);
  4538 
  4539 * Mutually recursive inductive definitions finally work in HOL;
  4540 
  4541 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4542 translates to the operator "split";
  4543 
  4544 
  4545 
  4546 New in Isabelle94-3
  4547 -------------------
  4548 
  4549 * new infix operator, addss, allowing the classical reasoner to
  4550 perform simplification at each step of its search.  Example:
  4551         fast_tac (cs addss ss)
  4552 
  4553 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4554 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4555 look like (a,b) instead of <a,b>;
  4556 
  4557 * PLEASE NOTE: CHOL will eventually replace HOL!
  4558 
  4559 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4560 It translates to the operator "split".  A new theory of integers is available;
  4561 
  4562 * In ZF, integer numerals now denote two's-complement binary integers.
  4563 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4564 
  4565 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4566 of the Axiom of Choice;
  4567 
  4568 
  4569 
  4570 New in Isabelle94-2
  4571 -------------------
  4572 
  4573 * Significantly faster resolution;
  4574 
  4575 * the different sections in a .thy file can now be mixed and repeated
  4576 freely;
  4577 
  4578 * Database of theorems for FOL, HOL and ZF.  New
  4579 commands including qed, qed_goal and bind_thm store theorems in the database.
  4580 
  4581 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4582 a given theory (thms_of), or find out what theory a theorem was proved in
  4583 (theory_of_thm);
  4584 
  4585 * Bugs fixed in the inductive definition and datatype packages;
  4586 
  4587 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4588 and HOL_dup_cs obsolete;
  4589 
  4590 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4591 have been removed;
  4592 
  4593 * Simpler definition of function space in ZF;
  4594 
  4595 * new results about cardinal and ordinal arithmetic in ZF;
  4596 
  4597 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4598 types;
  4599 
  4600 
  4601 $Id$