NEWS
author haftmann
Wed Jan 31 16:05:10 2007 +0100 (2007-01-31)
changeset 22218 30a8890d2967
parent 22152 df787d582323
child 22316 f662831459de
permissions -rw-r--r--
dropped lemma duplicates in HOL.thy
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: some popular names (e.g. "class", "fun", "help",
    19 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    20 
    21 * Legacy goal package: reduced interface to the bare minimum required
    22 to keep existing proof scripts running.  Most other user-level
    23 functions are now part of the OldGoals structure, which is *not* open
    24 by default (consider isatool expandshort before open OldGoals).
    25 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    26 these tend to cause confusion about the actual goal (!) context being
    27 used here, which is not necessarily the same as the_context().
    28 
    29 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    30 
    31 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    32 by default, which means that "prems" (and also "fixed variables") are
    33 suppressed from proof state output.  Note that the ProofGeneral
    34 settings mechanism allows to change and save options persistently, but
    35 older versions of Isabelle will fail to start up if a negative prems
    36 limit is imposed.
    37 
    38 * Local theory targets may be specified by non-nested blocks of
    39 ``context/locale/class ... begin'' followed by ``end''.  The body may
    40 contain definitions, theorems etc., including any derived mechanism
    41 that has been implemented on top of these primitives.  This concept
    42 generalizes the existing ``theorem (in ...)'' towards more versatility
    43 and scalability.
    44 
    45 * Proof General interface: proper undo of final 'end' command;
    46 discontinued Isabelle/classic mode (ML proof scripts).
    47 
    48 
    49 *** Document preparation ***
    50 
    51 * Added antiquotation @{theory name} which prints the given name,
    52 after checking that it refers to a valid ancestor theory in the
    53 current context.
    54 
    55 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    56 check the given source text as ML type/structure, printing verbatim.
    57 
    58 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    59 "c args == rhs" given in the current context.  (Any number of
    60 arguments may be given on the LHS.)
    61 
    62 
    63 
    64 *** Pure ***
    65 
    66 * class_package.ML offers a combination of axclasses and locales to
    67 achieve Haskell-like type classes in Isabelle. See
    68 HOL/ex/Classpackage.thy for examples.
    69 
    70 * Yet another code generator framework allows to generate executable
    71 code for ML and Haskell (including "class"es). A short usage sketch:
    72 
    73     internal compilation:
    74         code_gen <list of constants (term syntax)> (SML #)
    75     writing SML code to a file:
    76         code_gen <list of constants (term syntax)> (SML <filename>)
    77     writing Haskell code to a bunch of files:
    78         code_gen <list of constants (term syntax)> (Haskell <filename>)
    79 
    80 Reasonable default setup of framework in HOL/Main.
    81 
    82 See HOL/ex/Code*.thy for examples.
    83 
    84 Theorem attributs for selecting and transforming function equations theorems:
    85 
    86     [code fun]:       select a theorem as function equation for a specific constant
    87     [code nofun]:     deselect a theorem as function equation for a specific constant
    88     [code inline]:    select an equation theorem for unfolding (inlining) in place
    89     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    90 
    91 User-defined serializations (target in {SML, Haskell}):
    92 
    93     code_const <and-list of constants (term syntax)>
    94       {(target) <and-list of const target syntax>}+
    95 
    96     code_type <and-list of type constructors>
    97       {(target) <and-list of type target syntax>}+
    98 
    99     code_instance <and-list of instances>
   100       {(target)}+
   101         where instance ::= <type constructor> :: <class>
   102 
   103     code_class <and_list of classes>
   104       {(target) <and-list of class target syntax>}+
   105         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   106 
   107 For code_instance and code_class, target SML is silently ignored.
   108 
   109 See HOL theories and HOL/ex/Code*.thy for usage examples.  Doc/Isar/Advanced/Codegen/
   110 provides a tutorial.
   111 
   112 * Command 'no_translations' removes translation rules from theory
   113 syntax.
   114 
   115 * Overloaded definitions are now actually checked for acyclic
   116 dependencies.  The overloading scheme is slightly more general than
   117 that of Haskell98, although Isabelle does not demand an exact
   118 correspondence to type class and instance declarations.
   119 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   120 exotic versions of overloading -- at the discretion of the user!
   121 
   122 Polymorphic constants are represented via type arguments, i.e. the
   123 instantiation that matches an instance against the most general
   124 declaration given in the signature.  For example, with the declaration
   125 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   126 as c(nat).  Overloading is essentially simultaneous structural
   127 recursion over such type arguments.  Incomplete specification patterns
   128 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   129 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   130 Command 'print_theory' outputs the normalized system of recursive
   131 equations, see section "definitions".
   132 
   133 * Isar: improper proof element 'guess' is like 'obtain', but derives
   134 the obtained context from the course of reasoning!  For example:
   135 
   136   assume "EX x y. A x & B y"   -- "any previous fact"
   137   then guess x and y by clarify
   138 
   139 This technique is potentially adventurous, depending on the facts and
   140 proof tools being involved here.
   141 
   142 * Isar: known facts from the proof context may be specified as literal
   143 propositions, using ASCII back-quote syntax.  This works wherever
   144 named facts used to be allowed so far, in proof commands, proof
   145 methods, attributes etc.  Literal facts are retrieved from the context
   146 according to unification of type and term parameters.  For example,
   147 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   148 theorems in the current context, then these are valid literal facts:
   149 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   150 
   151 There is also a proof method "fact" which does the same composition
   152 for explicit goal states, e.g. the following proof texts coincide with
   153 certain special cases of literal facts:
   154 
   155   have "A" by fact                 ==  note `A`
   156   have "A ==> B" by fact           ==  note `A ==> B`
   157   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   158   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   159 
   160 * Isar: ":" (colon) is no longer a symbolic identifier character in
   161 outer syntax.  Thus symbolic identifiers may be used without
   162 additional white space in declarations like this: ``assume *: A''.
   163 
   164 * Isar: 'print_facts' prints all local facts of the current context,
   165 both named and unnamed ones.
   166 
   167 * Isar: 'def' now admits simultaneous definitions, e.g.:
   168 
   169   def x == "t" and y == "u"
   170 
   171 * Isar: added command 'unfolding', which is structurally similar to
   172 'using', but affects both the goal state and facts by unfolding given
   173 rewrite rules.  Thus many occurrences of the 'unfold' method or
   174 'unfolded' attribute may be replaced by first-class proof text.
   175 
   176 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   177 and command 'unfolding' now all support object-level equalities
   178 (potentially conditional).  The underlying notion of rewrite rule is
   179 analogous to the 'rule_format' attribute, but *not* that of the
   180 Simplifier (which is usually more generous).
   181 
   182 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   183 method expression within a sandbox consisting of the first N
   184 sub-goals, which need to exist.  For example, ``simp_all [3]''
   185 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   186 simplifies all new goals that emerge from applying rule foo to the
   187 originally first one.
   188 
   189 * Isar: schematic goals are no longer restricted to higher-order
   190 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   191 expected.
   192 
   193 * Isar: the conclusion of a long theorem statement is now either
   194 'shows' (a simultaneous conjunction, as before), or 'obtains'
   195 (essentially a disjunction of cases with local parameters and
   196 assumptions).  The latter allows to express general elimination rules
   197 adequately; in this notation common elimination rules look like this:
   198 
   199   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   200     assumes "EX x. P x"
   201     obtains x where "P x"
   202 
   203   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   204     assumes "A & B"
   205     obtains A and B
   206 
   207   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   208     assumes "A | B"
   209     obtains
   210       A
   211     | B
   212 
   213 The subsequent classical rules even refer to the formal "thesis"
   214 explicitly:
   215 
   216   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   217     obtains "~ thesis"
   218 
   219   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   220     obtains "thesis ==> something"
   221 
   222 The actual proof of an 'obtains' statement is analogous to that of the
   223 Isar proof element 'obtain', only that there may be several cases.
   224 Optional case names may be specified in parentheses; these will be
   225 available both in the present proof and as annotations in the
   226 resulting rule, for later use with the 'cases' method (cf. attribute
   227 case_names).
   228 
   229 * Isar: the assumptions of a long theorem statement are available as
   230 "assms" fact in the proof context.  This is more appropriate than the
   231 (historical) "prems", which refers to all assumptions of the current
   232 context, including those from the target locale, proof body etc.
   233 
   234 * Isar: 'print_statement' prints theorems from the current theory or
   235 proof context in long statement form, according to the syntax of a
   236 top-level lemma.
   237 
   238 * Isar: 'obtain' takes an optional case name for the local context
   239 introduction rule (default "that").
   240 
   241 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   242 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   243 to occur.
   244 
   245 * Pure: syntax "CONST name" produces a fully internalized constant
   246 according to the current context.  This is particularly useful for
   247 syntax translations that should refer to internal constant
   248 representations independently of name spaces.
   249 
   250 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   251 instead of "FOO ". This allows multiple binder declarations to coexist
   252 in the same context.  INCOMPATIBILITY.
   253 
   254 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   255 primitive that also works in a locale context (both for constants and
   256 fixed variables).  Type declaration and internal syntactic
   257 representation of given constants retrieved from the context.
   258 
   259 * Isar/locales: new derived specification elements 'axiomatization',
   260 'definition', 'abbreviation', which support type-inference, admit
   261 object-level specifications (equality, equivalence).  See also the
   262 isar-ref manual.  Examples:
   263 
   264   axiomatization
   265     eq  (infix "===" 50) where
   266     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   267 
   268   definition "f x y = x + y + 1"
   269   definition g where "g x = f x x"
   270 
   271   abbreviation
   272     neq  (infix "=!=" 50) where
   273     "x =!= y == ~ (x === y)"
   274 
   275 These specifications may be also used in a locale context.  Then the
   276 constants being introduced depend on certain fixed parameters, and the
   277 constant name is qualified by the locale base name.  An internal
   278 abbreviation takes care for convenient input and output, making the
   279 parameters implicit and using the original short name.  See also
   280 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   281 entities from a monomorphic theory.
   282 
   283 Presently, abbreviations are only available 'in' a target locale, but
   284 not inherited by general import expressions.  Also note that
   285 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   286 'translations' in common applications.
   287 
   288 Concrete syntax is attached to specified constants in internal form,
   289 independently of name spaces.  The parse tree representation is
   290 slightly different -- use 'notation' instead of raw 'syntax', and
   291 'translations' with explicit "CONST" markup to accommodate this.
   292 
   293 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   294 the current context.  Print mode "no_abbrevs" prevents inversion of
   295 abbreviations on output.
   296 
   297 * Isar/locales: improved parameter handling:
   298 - use of locales "var" and "struct" no longer necessary;
   299 - parameter renamings are no longer required to be injective.
   300   This enables, for example, to define a locale for endomorphisms thus:
   301   locale endom = homom mult mult h.
   302 
   303 * Isar/locales: changed the way locales with predicates are defined.
   304 Instead of accumulating the specification, the imported expression is
   305 now an interpretation.  INCOMPATIBILITY: different normal form of
   306 locale expressions.  In particular, in interpretations of locales with
   307 predicates, goals repesenting already interpreted fragments are not
   308 removed automatically.  Use methods `intro_locales' and
   309 `unfold_locales'; see below.
   310 
   311 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   312 provide backward reasoning on locales predicates.  The methods are
   313 aware of interpretations and discharge corresponding goals.
   314 `intro_locales' is less aggressive then `unfold_locales' and does not
   315 unfold predicates to assumptions.
   316 
   317 * Isar/locales: the order in which locale fragments are accumulated
   318 has changed.  This enables to override declarations from fragments due
   319 to interpretations -- for example, unwanted simp rules.
   320 
   321 * Provers/induct: improved internal context management to support
   322 local fixes and defines on-the-fly.  Thus explicit meta-level
   323 connectives !! and ==> are rarely required anymore in inductive goals
   324 (using object-logic connectives for this purpose has been long
   325 obsolete anyway).  The subsequent proof patterns illustrate advanced
   326 techniques of natural induction; general datatypes and inductive sets
   327 work analogously (see also src/HOL/Lambda for realistic examples).
   328 
   329 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   330 parameters:
   331 
   332   lemma
   333     fixes n :: nat and x :: 'a
   334     assumes a: "A n x"
   335     shows "P n x"
   336     using a                     -- {* make induct insert fact a *}
   337   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   338     case 0
   339     show ?case sorry
   340   next
   341     case (Suc n)
   342     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   343     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   344     show ?case sorry
   345   qed
   346 
   347 (2) This is how to perform induction over ``expressions of a certain
   348 form'', using a locally defined inductive parameter n == "a x"
   349 together with strengthening (the latter is usually required to get
   350 sufficiently flexible induction hypotheses):
   351 
   352   lemma
   353     fixes a :: "'a => nat"
   354     assumes a: "A (a x)"
   355     shows "P (a x)"
   356     using a
   357   proof (induct n == "a x" arbitrary: x)
   358     ...
   359 
   360 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   361 particular technique.
   362 
   363 (3) This is how to perform existential reasoning ('obtains' or
   364 'obtain') by induction, while avoiding explicit object-logic
   365 encodings:
   366 
   367   lemma
   368     fixes n :: nat
   369     obtains x :: 'a where "P n x" and "Q n x"
   370   proof (induct n arbitrary: thesis)
   371     case 0
   372     obtain x where "P 0 x" and "Q 0 x" sorry
   373     then show thesis by (rule 0)
   374   next
   375     case (Suc n)
   376     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   377     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   378     then show thesis by (rule Suc.prems)
   379   qed
   380 
   381 Here the 'arbitrary: thesis' specification essentially modifies the
   382 scope of the formal thesis parameter, in order to the get the whole
   383 existence statement through the induction as expected.
   384 
   385 * Provers/induct: mutual induction rules are now specified as a list
   386 of rule sharing the same induction cases.  HOL packages usually
   387 provide foo_bar.inducts for mutually defined items foo and bar
   388 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   389 specify mutual induction rules differently, i.e. like this:
   390 
   391   (induct rule: foo_bar.inducts)
   392   (induct set: foo bar)
   393   (induct type: foo bar)
   394 
   395 The ML function ProjectRule.projections turns old-style rules into the
   396 new format.
   397 
   398 * Provers/induct: improved handling of simultaneous goals.  Instead of
   399 introducing object-level conjunction, the statement is now split into
   400 several conclusions, while the corresponding symbolic cases are
   401 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   402 explicitly.  For example:
   403 
   404   lemma
   405     fixes n :: nat
   406     shows "P n" and "Q n"
   407   proof (induct n)
   408     case 0 case 1
   409     show "P 0" sorry
   410   next
   411     case 0 case 2
   412     show "Q 0" sorry
   413   next
   414     case (Suc n) case 1
   415     note `P n` and `Q n`
   416     show "P (Suc n)" sorry
   417   next
   418     case (Suc n) case 2
   419     note `P n` and `Q n`
   420     show "Q (Suc n)" sorry
   421   qed
   422 
   423 The split into subcases may be deferred as follows -- this is
   424 particularly relevant for goal statements with local premises.
   425 
   426   lemma
   427     fixes n :: nat
   428     shows "A n ==> P n" and "B n ==> Q n"
   429   proof (induct n)
   430     case 0
   431     {
   432       case 1
   433       note `A 0`
   434       show "P 0" sorry
   435     next
   436       case 2
   437       note `B 0`
   438       show "Q 0" sorry
   439     }
   440   next
   441     case (Suc n)
   442     note `A n ==> P n` and `B n ==> Q n`
   443     {
   444       case 1
   445       note `A (Suc n)`
   446       show "P (Suc n)" sorry
   447     next
   448       case 2
   449       note `B (Suc n)`
   450       show "Q (Suc n)" sorry
   451     }
   452   qed
   453 
   454 If simultaneous goals are to be used with mutual rules, the statement
   455 needs to be structured carefully as a two-level conjunction, using
   456 lists of propositions separated by 'and':
   457 
   458   lemma
   459     shows "a : A ==> P1 a"
   460           "a : A ==> P2 a"
   461       and "b : B ==> Q1 b"
   462           "b : B ==> Q2 b"
   463           "b : B ==> Q3 b"
   464   proof (induct set: A B)
   465 
   466 * Provers/induct: support coinduction as well.  See
   467 src/HOL/Library/Coinductive_List.thy for various examples.
   468 
   469 * Attribute "symmetric" produces result with standardized schematic
   470 variables (index 0).  Potential INCOMPATIBILITY.
   471 
   472 * Simplifier: by default the simplifier trace only shows top level
   473 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   474 default. Thus there is less danger of being flooded by the trace. The
   475 trace indicates where parts have been suppressed.
   476   
   477 * Provers/classical: removed obsolete classical version of elim_format
   478 attribute; classical elim/dest rules are now treated uniformly when
   479 manipulating the claset.
   480 
   481 * Provers/classical: stricter checks to ensure that supplied intro,
   482 dest and elim rules are well-formed; dest and elim rules must have at
   483 least one premise.
   484 
   485 * Provers/classical: attributes dest/elim/intro take an optional
   486 weight argument for the rule (just as the Pure versions).  Weights are
   487 ignored by automated tools, but determine the search order of single
   488 rule steps.
   489 
   490 * Syntax: input syntax now supports dummy variable binding "%_. b",
   491 where the body does not mention the bound variable.  Note that dummy
   492 patterns implicitly depend on their context of bounds, which makes
   493 "{_. _}" match any set comprehension as expected.  Potential
   494 INCOMPATIBILITY -- parse translations need to cope with syntactic
   495 constant "_idtdummy" in the binding position.
   496 
   497 * Syntax: removed obsolete syntactic constant "_K" and its associated
   498 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   499 for example "A -> B" => "Pi A (%_. B)".
   500 
   501 * Pure: 'class_deps' command visualizes the subclass relation, using
   502 the graph browser tool.
   503 
   504 * Pure: 'print_theory' now suppresses entities with internal name
   505 (trailing "_") by default; use '!' option for full details.
   506 
   507 
   508 *** HOL ***
   509 
   510 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   511 INCOMPATIBILITY.
   512 
   513 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   514 INCOMPATIBILITY.
   515 
   516 * Added syntactic class "size"; overloaded constant "size" now has
   517 type "'a::size ==> bool"
   518 
   519 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   520 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd"
   521 "Divides.dvd". INCOMPATIBILITY.
   522 
   523 * Added method "lexicographic_order" automatically synthesizes
   524 termination relations as lexicographic combinations of size measures
   525 -- 'function' package.
   526 
   527 * HOL/records: generalised field-update to take a function on the
   528 field rather than the new value: r(|A := x|) is translated to A_update
   529 (K x) r The K-combinator that is internally used is called K_record.
   530 INCOMPATIBILITY: Usage of the plain update functions has to be
   531 adapted.
   532  
   533 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   534 0 * x = 0, which are required for a semiring.  Richer structures do
   535 not inherit from semiring_0 anymore, because this property is a
   536 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   537 semiring_0, there is more to prove, but this is mostly trivial.
   538 
   539 * axclass "recpower" was generalized to arbitrary monoids, not just
   540 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   541 commutativity or a semiring property, add the corresponding classes.
   542 
   543 * Unified locale partial_order with class definition (cf. theory
   544 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   545 
   546 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   547 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   548 Isar level, use abbreviations instead.
   549 
   550 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   551 rarely occuring name references (e.g. ``List.op mem.simps'') require
   552 renaming (e.g. ``List.memberl.simps'').
   553 
   554 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   555 INCOMPATIBILITY.
   556 
   557 * Added theory Code_Generator providing class 'eq', allowing for code
   558 generation with polymorphic equality.
   559 
   560 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   561 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   562 significant changes for setting up numeral syntax for types:
   563 
   564   - new constants Numeral.pred and Numeral.succ instead
   565       of former Numeral.bin_pred and Numeral.bin_succ.
   566   - Use integer operations instead of bin_add, bin_mult and so on.
   567   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   568   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   569 
   570 See HOL/Integ/IntArith.thy for an example setup.
   571 
   572 * New top level command 'normal_form' computes the normal form of a
   573 term that may contain free variables. For example ``normal_form
   574 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   575 suitable for heavy-duty computations because the functions are
   576 compiled to ML first.
   577 
   578 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   579 25 like -->); output depends on the "iff" print_mode, the default is
   580 "A = B" (with priority 50).
   581 
   582 * Renamed constants in HOL.thy and Orderings.thy:
   583     op +   ~> HOL.plus
   584     op -   ~> HOL.minus
   585     uminus ~> HOL.uminus
   586     op *   ~> HOL.times
   587     op <   ~> Orderings.less
   588     op <=  ~> Orderings.less_eq
   589 
   590 Adaptions may be required in the following cases:
   591 
   592 a) User-defined constants using any of the names "plus", "minus", "times",
   593 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   594 may go wrong.
   595 INCOMPATIBILITY: use more specific names.
   596 
   597 b) Variables named "plus", "minus", "times", "less", "less_eq"
   598 INCOMPATIBILITY: use more specific names.
   599 
   600 c) Permutative equations (e.g. "a + b = b + a")
   601 Since the change of names also changes the order of terms, permutative
   602 rewrite rules may get applied in a different order. Experience shows that
   603 this is rarely the case (only two adaptions in the whole Isabelle
   604 distribution).
   605 INCOMPATIBILITY: rewrite proofs
   606 
   607 d) ML code directly refering to constant names
   608 This in general only affects hand-written proof tactics, simprocs and so on.
   609 INCOMPATIBILITY: grep your sourcecode and replace names.
   610 
   611 * Relations less (<) and less_eq (<=) are also available on type bool.
   612 Modified syntax to disallow nesting without explicit parentheses,
   613 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   614 
   615 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   616 
   617 * Relation composition operator "op O" now has precedence 75 and binds
   618 stronger than union and intersection. INCOMPATIBILITY.
   619 
   620 * The old set interval syntax "{m..n(}" (and relatives) has been
   621 removed.  Use "{m..<n}" (and relatives) instead.
   622 
   623 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   624 "t = s" to False (by simproc "neq_simproc").  For backward
   625 compatibility this can be disabled by ML "reset use_neq_simproc".
   626 
   627 * "m dvd n" where m and n are numbers is evaluated to True/False by
   628 simp.
   629 
   630 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   631 
   632 * Theorem setsum_mult renamed to setsum_right_distrib.
   633 
   634 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   635 ``rule'' method.
   636 
   637 * Reimplemented methods ``sat'' and ``satx'', with several
   638 improvements: goals no longer need to be stated as "<prems> ==>
   639 False", equivalences (i.e. "=" on type bool) are handled, variable
   640 names of the form "lit_<n>" are no longer reserved, significant
   641 speedup.
   642 
   643 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   644 zChaff is still supported as well.
   645 
   646 * 'inductive' and 'datatype': provide projections of mutual rules,
   647 bundled as foo_bar.inducts;
   648 
   649 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   650 Library.
   651 
   652 * Library: moved theory Accessible_Part to main HOL.
   653 
   654 * Library: added theory Coinductive_List of potentially infinite lists
   655 as greatest fixed-point.
   656 
   657 * Library: added theory AssocList which implements (finite) maps as
   658 association lists.
   659 
   660 * Added proof method ``evaluation'' for efficiently solving a goal
   661 (i.e. a boolean expression) by compiling it to ML. The goal is
   662 "proved" (via an oracle) if it evaluates to True.
   663 
   664 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   665 also when invoked by the simplifier.  This results in the simplifier
   666 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   667 fast_arith_split_limit to 0 to obtain the old behavior.
   668 
   669 * Support for hex (0x20) and binary (0b1001) numerals.
   670 
   671 * New method: reify eqs (t), where eqs are equations for an
   672 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   673 parameter, computes a term s::'b and a list xs::'a list and proves the
   674 theorem I xs s = t. This is also known as reification or quoting. The
   675 resulting theorem is applied to the subgoal to substitute t with I xs
   676 s.  If t is omitted, the subgoal itself is reified.
   677 
   678 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   679 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   680 where f is supposed to be a computable function (in the sense of code
   681 generattion). The method uses reify to compute s and xs as above then
   682 applies corr_thm and uses normalization by evaluation to "prove" f s =
   683 r and finally gets the theorem t = r, which is again applied to the
   684 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   685 
   686 * Reflection: Automatic refification now handels binding, an example
   687 is available in HOL/ex/ReflectionEx.thy
   688 
   689 
   690 *** HOL-Algebra ***
   691 
   692 * Formalisation of ideals and the quotient construction over rings.
   693 
   694 * Order and lattice theory no longer based on records.
   695 INCOMPATIBILITY.
   696 
   697 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   698 greatest_closed.  INCOMPATIBILITY.
   699 
   700 * Method algebra is now set up via an attribute.  For examples see
   701 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   702 of algebraic structures.
   703 
   704 * Renamed theory CRing to Ring.
   705 
   706 
   707 *** HOL-Complex ***
   708 
   709 * Theory Real: new method ferrack implements quantifier elimination
   710 for linear arithmetic over the reals. The quantifier elimination
   711 feature is used only for decision, for compatibility with arith. This
   712 means a goal is either solved or left unchanged, no simplification.
   713 
   714 * Real: New axiomatic classes formalize real normed vector spaces and
   715 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   716 and norm :: 'a => real.
   717 
   718 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   719 from reals into other types. The overloaded constant Reals :: 'a set
   720 is now defined as range of_real; potential INCOMPATIBILITY.
   721 
   722 * Hyperreal: Several constants that previously worked only for the
   723 reals have been generalized, so they now work over arbitrary vector
   724 spaces. Type annotations may need to be added in some cases; potential
   725 INCOMPATIBILITY.
   726 
   727   Infinitesimal  :: ('a::real_normed_vector) star set"
   728   HFinite        :: ('a::real_normed_vector) star set"
   729   HInfinite      :: ('a::real_normed_vector) star set"
   730   approx         :: ('a::real_normed_vector) star => 'a star => bool
   731   monad          :: ('a::real_normed_vector) star => 'a star set
   732   galaxy         :: ('a::real_normed_vector) star => 'a star set
   733   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   734   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   735   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   736   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   737   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   738   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   739   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   740 
   741 * Complex: Some complex-specific constants are now abbreviations for
   742 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   743 hnorm.  Other constants have been entirely removed in favor of the
   744 polymorphic versions (INCOMPATIBILITY):
   745 
   746   approx        <-- capprox
   747   HFinite       <-- CFinite
   748   HInfinite     <-- CInfinite
   749   Infinitesimal <-- CInfinitesimal
   750   monad         <-- cmonad
   751   galaxy        <-- cgalaxy
   752   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   753   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   754   (ns)deriv     <-- (ns)cderiv
   755 
   756 
   757 *** ML ***
   758 
   759 * ML within Isar: antiquotations allow to embed statically-checked
   760 formal entities in the source, referring to the context available at
   761 compile-time.  For example:
   762 
   763 ML {* @{typ "'a => 'b"} *}
   764 ML {* @{term "%x. x"} *}
   765 ML {* @{prop "x == y"} *}
   766 ML {* @{ctyp "'a => 'b"} *}
   767 ML {* @{cterm "%x. x"} *}
   768 ML {* @{cprop "x == y"} *}
   769 ML {* @{thm asm_rl} *}
   770 ML {* @{thms asm_rl} *}
   771 ML {* @{context} *}
   772 ML {* @{theory} *}
   773 ML {* @{theory Pure} *}
   774 ML {* @{simpset} *}
   775 ML {* @{claset} *}
   776 ML {* @{clasimpset} *}
   777 
   778 The same works for sources being ``used'' within an Isar context.
   779 
   780 * ML in Isar: improved error reporting; extra verbosity with
   781 Toplevel.debug enabled.
   782 
   783 * Pure/library:
   784 
   785   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   786   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   787 
   788 The semantics of "burrow" is: "take a function with *simulatanously*
   789 transforms a list of value, and apply it *simulatanously* to a list of
   790 list of values of the appropriate type". Compare this with "map" which
   791 would *not* apply its argument function simulatanously but in
   792 sequence; "fold_burrow" has an additional context.
   793 
   794 * Pure/library: functions map2 and fold2 with curried syntax for
   795 simultanous mapping and folding:
   796 
   797     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   798     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   799 
   800 * Pure/library: indexed lists - some functions in the Isabelle library
   801 treating lists over 'a as finite mappings from [0...n] to 'a have been
   802 given more convenient names and signatures reminiscent of similar
   803 functions for alists, tables, etc:
   804 
   805   val nth: 'a list -> int -> 'a 
   806   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   807   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   808 
   809 Note that fold_index starts counting at index 0, not 1 like foldln
   810 used to.
   811 
   812 * Pure/library: added general ``divide_and_conquer'' combinator on
   813 lists.
   814 
   815 * Pure/General/table.ML: the join operations now works via exceptions
   816 DUP/SAME instead of type option.  This is simpler in simple cases, and
   817 admits slightly more efficient complex applications.
   818 
   819 * Pure: datatype Context.generic joins theory/Proof.context and
   820 provides some facilities for code that works in either kind of
   821 context, notably GenericDataFun for uniform theory and proof data.
   822 
   823 * Pure: 'advanced' translation functions (parse_translation etc.) now
   824 use Context.generic instead of just theory.
   825 
   826 * Pure: simplified internal attribute type, which is now always
   827 Context.generic * thm -> Context.generic * thm.  Global (theory)
   828 vs. local (Proof.context) attributes have been discontinued, while
   829 minimizing code duplication.  Thm.rule_attribute and
   830 Thm.declaration_attribute build canonical attributes; see also
   831 structure Context for further operations on Context.generic, notably
   832 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   833 declarations and definitions.
   834 
   835 * Pure/kernel: consts certification ignores sort constraints given in
   836 signature declarations.  (This information is not relevant to the
   837 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   838 potential INCOMPATIBILITY.
   839 
   840 * Pure: axiomatic type classes are now purely definitional, with
   841 explicit proofs of class axioms and super class relations performed
   842 internally.  See Pure/axclass.ML for the main internal interfaces --
   843 notably AxClass.define_class supercedes AxClass.add_axclass, and
   844 AxClass.axiomatize_class/classrel/arity supercede
   845 Sign.add_classes/classrel/arities.
   846 
   847 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   848 global/local versions on theory vs. Proof.context have been
   849 discontinued; Attrib.syntax and Method.syntax have been adapted
   850 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   851 attributes, methods, etc.
   852 
   853 * Pure: several functions of signature "... -> theory -> theory * ..."
   854 have been reoriented to "... -> theory -> ... * theory" in order to
   855 allow natural usage in combination with the ||>, ||>>, |-> and
   856 fold_map combinators.
   857 
   858 * Pure: official theorem names (closed derivations) and additional
   859 comments (tags) are now strictly separate.  Name hints -- which are
   860 maintained as tags -- may be attached any time without affecting the
   861 derivation.
   862 
   863 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   864 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   865 achieve the old behaviour.
   866 
   867 * Pure: the "Goal" constant is now called "prop", supporting a
   868 slightly more general idea of ``protecting'' meta-level rule
   869 statements.
   870 
   871 * Pure: Logic.(un)varify only works in a global context, which is now
   872 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   873 Logic.legacy_(un)varify as temporary workaround.
   874 
   875 * Pure: structure Name provides scalable operations for generating
   876 internal variable names, notably Name.variants etc.  This replaces
   877 some popular functions from term.ML:
   878 
   879   Term.variant		->  Name.variant
   880   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   881   Term.invent_names	->  Name.invent_list
   882 
   883 Note that low-level renaming rarely occurs in new code -- operations
   884 from structure Variable are used instead (see below).
   885 
   886 * Pure: structure Variable provides fundamental operations for proper
   887 treatment of fixed/schematic variables in a context.  For example,
   888 Variable.import introduces fixes for schematics of given facts and
   889 Variable.export reverses the effect (up to renaming) -- this replaces
   890 various freeze_thaw operations.
   891 
   892 * Pure: structure Goal provides simple interfaces for
   893 init/conclude/finish and tactical prove operations (replacing former
   894 Tactic.prove).  Goal.prove is the canonical way to prove results
   895 within a given context; Goal.prove_global is a degraded version for
   896 theory level goals, including a global Drule.standard.  Note that
   897 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   898 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   899 in a locale context).
   900 
   901 * Isar: simplified treatment of user-level errors, using exception
   902 ERROR of string uniformly.  Function error now merely raises ERROR,
   903 without any side effect on output channels.  The Isar toplevel takes
   904 care of proper display of ERROR exceptions.  ML code may use plain
   905 handle/can/try; cat_error may be used to concatenate errors like this:
   906 
   907   ... handle ERROR msg => cat_error msg "..."
   908 
   909 Toplevel ML code (run directly or through the Isar toplevel) may be
   910 embedded into the Isar toplevel with exception display/debug like
   911 this:
   912 
   913   Isar.toplevel (fn () => ...)
   914 
   915 INCOMPATIBILITY, removed special transform_error facilities, removed
   916 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   917 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   918 -- use plain ERROR instead.
   919 
   920 * Isar: theory setup now has type (theory -> theory), instead of a
   921 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   922 
   923 * Isar: installed ML toplevel pretty printer for type Proof.context,
   924 subject to ProofContext.debug/verbose flags.
   925 
   926 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   927 theory before entering a proof state.  Transactions now always see a
   928 quasi-functional intermediate checkpoint, both in interactive and
   929 batch mode.
   930 
   931 * Simplifier: the simpset of a running simplification process now
   932 contains a proof context (cf. Simplifier.the_context), which is the
   933 very context that the initial simpset has been retrieved from (by
   934 simpset_of/local_simpset_of).  Consequently, all plug-in components
   935 (solver, looper etc.) may depend on arbitrary proof data.
   936 
   937 * Simplifier.inherit_context inherits the proof context (plus the
   938 local bounds) of the current simplification process; any simproc
   939 etc. that calls the Simplifier recursively should do this!  Removed
   940 former Simplifier.inherit_bounds, which is already included here --
   941 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   942 specify an explicit context using Simplifier.context/theory_context.
   943 
   944 * Simplifier/Classical Reasoner: more abstract interfaces
   945 change_simpset/claset for modifying the simpset/claset reference of a
   946 theory; raw versions simpset/claset_ref etc. have been discontinued --
   947 INCOMPATIBILITY.
   948 
   949 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   950 "Trueprop" etc.
   951 
   952 
   953 *** System ***
   954 
   955 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   956 locations -- now includes the Isabelle version identifier as well.
   957 This simplifies use of multiple Isabelle installations.
   958 
   959 * isabelle-process: option -S (secure mode) disables some critical
   960 operations, notably runtime compilation and evaluation of ML source
   961 code.
   962 
   963 
   964 New in Isabelle2005 (October 2005)
   965 ----------------------------------
   966 
   967 *** General ***
   968 
   969 * Theory headers: the new header syntax for Isar theories is
   970 
   971   theory <name>
   972   imports <theory1> ... <theoryN>
   973   uses <file1> ... <fileM>
   974   begin
   975 
   976 where the 'uses' part is optional.  The previous syntax
   977 
   978   theory <name> = <theory1> + ... + <theoryN>:
   979 
   980 will disappear in the next release.  Use isatool fixheaders to convert
   981 existing theory files.  Note that there is no change in ancient
   982 non-Isar theories now, but these will disappear soon.
   983 
   984 * Theory loader: parent theories can now also be referred to via
   985 relative and absolute paths.
   986 
   987 * Command 'find_theorems' searches for a list of criteria instead of a
   988 list of constants. Known criteria are: intro, elim, dest, name:string,
   989 simp:term, and any term. Criteria can be preceded by '-' to select
   990 theorems that do not match. Intro, elim, dest select theorems that
   991 match the current goal, name:s selects theorems whose fully qualified
   992 name contain s, and simp:term selects all simplification rules whose
   993 lhs match term.  Any other term is interpreted as pattern and selects
   994 all theorems matching the pattern. Available in ProofGeneral under
   995 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   996 
   997   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   998 
   999 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1000 matching the current goal as introduction rule and not having "HOL."
  1001 in their name (i.e. not being defined in theory HOL).
  1002 
  1003 * Command 'thms_containing' has been discontinued in favour of
  1004 'find_theorems'; INCOMPATIBILITY.
  1005 
  1006 * Communication with Proof General is now 8bit clean, which means that
  1007 Unicode text in UTF-8 encoding may be used within theory texts (both
  1008 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1009 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1010 
  1011   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1012   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1013 
  1014 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1015 Classical Reasoner.  Typical big applications run around 2 times
  1016 faster.
  1017 
  1018 
  1019 *** Document preparation ***
  1020 
  1021 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1022 of raw sources.  Only those symbols that do not require additional
  1023 LaTeX packages (depending on comments in isabellesym.sty) are
  1024 displayed properly, everything else is left verbatim.  isatool display
  1025 and isatool print are used as front ends (these are subject to the
  1026 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1027 
  1028 * Command tags control specific markup of certain regions of text,
  1029 notably folding and hiding.  Predefined tags include "theory" (for
  1030 theory begin and end), "proof" for proof commands, and "ML" for
  1031 commands involving ML code; the additional tags "visible" and
  1032 "invisible" are unused by default.  Users may give explicit tag
  1033 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1034 interpretation of tags is determined by the LaTeX job during document
  1035 preparation: see option -V of isatool usedir, or options -n and -t of
  1036 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1037 \isadroptag.
  1038 
  1039 Several document versions may be produced at the same time via isatool
  1040 usedir (the generated index.html will link all of them).  Typical
  1041 specifications include ''-V document=theory,proof,ML'' to present
  1042 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1043 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1044 these parts without any formal replacement text.  The Isabelle site
  1045 default settings produce ''document'' and ''outline'' versions as
  1046 specified above.
  1047 
  1048 * Several new antiquotations:
  1049 
  1050   @{term_type term} prints a term with its type annotated;
  1051 
  1052   @{typeof term} prints the type of a term;
  1053 
  1054   @{const const} is the same as @{term const}, but checks that the
  1055   argument is a known logical constant;
  1056 
  1057   @{term_style style term} and @{thm_style style thm} print a term or
  1058   theorem applying a "style" to it
  1059 
  1060   @{ML text}
  1061 
  1062 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1063 definitions, equations, inequations etc., 'concl' printing only the
  1064 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1065 to print the specified premise.  TermStyle.add_style provides an ML
  1066 interface for introducing further styles.  See also the "LaTeX Sugar"
  1067 document practical applications.  The ML antiquotation prints
  1068 type-checked ML expressions verbatim.
  1069 
  1070 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1071 and 'text' support optional locale specification '(in loc)', which
  1072 specifies the default context for interpreting antiquotations.  For
  1073 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1074 
  1075 * Option 'locale=NAME' of antiquotations specifies an alternative
  1076 context interpreting the subsequent argument.  For example: @{thm
  1077 [locale=lattice] inf_assoc}.
  1078 
  1079 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1080 a proof context.
  1081 
  1082 * Proper output of antiquotations for theory commands involving a
  1083 proof context (such as 'locale' or 'theorem (in loc) ...').
  1084 
  1085 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1086 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1087 
  1088 * isatool usedir: new option -C (default true) controls whether option
  1089 -D should include a copy of the original document directory; -C false
  1090 prevents unwanted effects such as copying of administrative CVS data.
  1091 
  1092 
  1093 *** Pure ***
  1094 
  1095 * Considerably improved version of 'constdefs' command.  Now performs
  1096 automatic type-inference of declared constants; additional support for
  1097 local structure declarations (cf. locales and HOL records), see also
  1098 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1099 sequential dependencies of definitions within a single 'constdefs'
  1100 section; moreover, the declared name needs to be an identifier.  If
  1101 all fails, consider to fall back on 'consts' and 'defs' separately.
  1102 
  1103 * Improved indexed syntax and implicit structures.  First of all,
  1104 indexed syntax provides a notational device for subscripted
  1105 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1106 expressions.  Secondly, in a local context with structure
  1107 declarations, number indexes \<^sub>n or the empty index (default
  1108 number 1) refer to a certain fixed variable implicitly; option
  1109 show_structs controls printing of implicit structures.  Typical
  1110 applications of these concepts involve record types and locales.
  1111 
  1112 * New command 'no_syntax' removes grammar declarations (and
  1113 translations) resulting from the given syntax specification, which is
  1114 interpreted in the same manner as for the 'syntax' command.
  1115 
  1116 * 'Advanced' translation functions (parse_translation etc.) may depend
  1117 on the signature of the theory context being presently used for
  1118 parsing/printing, see also isar-ref manual.
  1119 
  1120 * Improved 'oracle' command provides a type-safe interface to turn an
  1121 ML expression of type theory -> T -> term into a primitive rule of
  1122 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1123 is already included here); see also FOL/ex/IffExample.thy;
  1124 INCOMPATIBILITY.
  1125 
  1126 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1127 before); "cI" is no longer bound, use "c.intro" instead.
  1128 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1129 axclasses vs. locales.
  1130 
  1131 * Improved internal renaming of symbolic identifiers -- attach primes
  1132 instead of base 26 numbers.
  1133 
  1134 * New flag show_question_marks controls printing of leading question
  1135 marks in schematic variable names.
  1136 
  1137 * In schematic variable names, *any* symbol following \<^isub> or
  1138 \<^isup> is now treated as part of the base name.  For example, the
  1139 following works without printing of awkward ".0" indexes:
  1140 
  1141   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1142     by simp
  1143 
  1144 * Inner syntax includes (*(*nested*) comments*).
  1145 
  1146 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1147 annotations as "(00...)".
  1148 
  1149 * Clear separation of logical types and nonterminals, where the latter
  1150 may only occur in 'syntax' specifications or type abbreviations.
  1151 Before that distinction was only partially implemented via type class
  1152 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1153 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1154 exotic syntax specifications may require further adaption
  1155 (e.g. Cube/Cube.thy).
  1156 
  1157 * Removed obsolete type class "logic", use the top sort {} instead.
  1158 Note that non-logical types should be declared as 'nonterminals'
  1159 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1160 specifications.
  1161 
  1162 * Attributes 'induct' and 'cases': type or set names may now be
  1163 locally fixed variables as well.
  1164 
  1165 * Simplifier: can now control the depth to which conditional rewriting
  1166 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1167 Limit.
  1168 
  1169 * Simplifier: simplification procedures may now take the current
  1170 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1171 interface), which is very useful for calling the Simplifier
  1172 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1173 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1174 low-level mk_simproc no longer applies Logic.varify internally, to
  1175 allow for use in a context of fixed variables.
  1176 
  1177 * thin_tac now works even if the assumption being deleted contains !!
  1178 or ==>.  More generally, erule now works even if the major premise of
  1179 the elimination rule contains !! or ==>.
  1180 
  1181 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1182 
  1183 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1184 from Pure, which contains all common declarations already.  Both
  1185 theories are defined via plain Isabelle/Isar .thy files.
  1186 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1187 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1188 use isatool fixcpure to adapt your theory and ML sources.
  1189 
  1190 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1191 selections of theorems in named facts via index ranges.
  1192 
  1193 * 'print_theorems': in theory mode, really print the difference
  1194 wrt. the last state (works for interactive theory development only),
  1195 in proof mode print all local facts (cf. 'print_facts');
  1196 
  1197 * 'hide': option '(open)' hides only base names.
  1198 
  1199 * More efficient treatment of intermediate checkpoints in interactive
  1200 theory development.
  1201 
  1202 * Code generator is now invoked via code_module (incremental code
  1203 generation) and code_library (modular code generation, ML structures
  1204 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1205 must be quoted when used as identifiers.
  1206 
  1207 * New 'value' command for reading, evaluating and printing terms using
  1208 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1209 quoted when used as identifier.
  1210 
  1211 
  1212 *** Locales ***
  1213 
  1214 * New commands for the interpretation of locale expressions in
  1215 theories (1), locales (2) and proof contexts (3).  These generate
  1216 proof obligations from the expression specification.  After the
  1217 obligations have been discharged, theorems of the expression are added
  1218 to the theory, target locale or proof context.  The synopsis of the
  1219 commands is a follows:
  1220 
  1221   (1) interpretation expr inst
  1222   (2) interpretation target < expr
  1223   (3) interpret expr inst
  1224 
  1225 Interpretation in theories and proof contexts require a parameter
  1226 instantiation of terms from the current context.  This is applied to
  1227 specifications and theorems of the interpreted expression.
  1228 Interpretation in locales only permits parameter renaming through the
  1229 locale expression.  Interpretation is smart in that interpretations
  1230 that are active already do not occur in proof obligations, neither are
  1231 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1232 inspect active interpretations of a particular locale.  For details,
  1233 see the Isar Reference manual.  Examples can be found in
  1234 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1235 
  1236 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1237 'interpret' instead.
  1238 
  1239 * New context element 'constrains' for adding type constraints to
  1240 parameters.
  1241 
  1242 * Context expressions: renaming of parameters with syntax
  1243 redeclaration.
  1244 
  1245 * Locale declaration: 'includes' disallowed.
  1246 
  1247 * Proper static binding of attribute syntax -- i.e. types / terms /
  1248 facts mentioned as arguments are always those of the locale definition
  1249 context, independently of the context of later invocations.  Moreover,
  1250 locale operations (renaming and type / term instantiation) are applied
  1251 to attribute arguments as expected.
  1252 
  1253 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1254 actual attributes; rare situations may require Attrib.attribute to
  1255 embed those attributes into Attrib.src that lack concrete syntax.
  1256 Attribute implementations need to cooperate properly with the static
  1257 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1258 Attrib.XXX_thm etc. already do the right thing without further
  1259 intervention.  Only unusual applications -- such as "where" or "of"
  1260 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1261 on the context and the facts involved -- may have to assign parsed
  1262 values to argument tokens explicitly.
  1263 
  1264 * Changed parameter management in theorem generation for long goal
  1265 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1266 theorem statement in rare situations.
  1267 
  1268 * Locale inspection command 'print_locale' omits notes elements.  Use
  1269 'print_locale!' to have them included in the output.
  1270 
  1271 
  1272 *** Provers ***
  1273 
  1274 * Provers/hypsubst.ML: improved version of the subst method, for
  1275 single-step rewriting: it now works in bound variable contexts. New is
  1276 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1277 rewrite a different subterm than the original subst method, which is
  1278 still available as 'simplesubst'.
  1279 
  1280 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1281 and quasi orders.
  1282 
  1283 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1284 reflexive-transitive closure of relations.
  1285 
  1286 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1287 limit (previously hard-coded with a value of 20) user-definable.
  1288 
  1289 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1290 is peformed already.  Object-logics merely need to finish their
  1291 initial simpset configuration as before.  INCOMPATIBILITY.
  1292 
  1293 
  1294 *** HOL ***
  1295 
  1296 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1297 
  1298   syntax (epsilon)
  1299     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1300 
  1301 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1302 and x-symbol; use option '-m epsilon' to get it actually printed.
  1303 Moreover, the mathematically important symbolic identifier \<epsilon>
  1304 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1305 
  1306 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1307 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1308 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1309 support corresponding Isar calculations.
  1310 
  1311 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1312 instead of ":".
  1313 
  1314 * theory SetInterval: changed the syntax for open intervals:
  1315 
  1316   Old       New
  1317   {..n(}    {..<n}
  1318   {)n..}    {n<..}
  1319   {m..n(}   {m..<n}
  1320   {)m..n}   {m<..n}
  1321   {)m..n(}  {m<..<n}
  1322 
  1323 The old syntax is still supported but will disappear in the next
  1324 release.  For conversion use the following Emacs search and replace
  1325 patterns (these are not perfect but work quite well):
  1326 
  1327   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1328   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1329 
  1330 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1331 equalities in commutative rings; method 'algebra' provides a generic
  1332 interface.
  1333 
  1334 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1335 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1336 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1337 be a tuple pattern.
  1338 
  1339 Some new syntax forms are available:
  1340 
  1341   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1342   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1343   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1344   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1345 
  1346 The latter form "\<Sum>x < k. e" used to be based on a separate
  1347 function "Summation", which has been discontinued.
  1348 
  1349 * theory Finite_Set: in structured induction proofs, the insert case
  1350 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1351 (insert F x)'.
  1352 
  1353 * The 'refute' command has been extended to support a much larger
  1354 fragment of HOL, including axiomatic type classes, constdefs and
  1355 typedefs, inductive datatypes and recursion.
  1356 
  1357 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1358 Requires zChaff with proof generation to be installed.  See
  1359 HOL/ex/SAT_Examples.thy for examples.
  1360 
  1361 * Datatype induction via method 'induct' now preserves the name of the
  1362 induction variable. For example, when proving P(xs::'a list) by
  1363 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1364 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1365 in unstructured proof scripts.
  1366 
  1367 * Reworked implementation of records.  Improved scalability for
  1368 records with many fields, avoiding performance problems for type
  1369 inference. Records are no longer composed of nested field types, but
  1370 of nested extension types. Therefore the record type only grows linear
  1371 in the number of extensions and not in the number of fields.  The
  1372 top-level (users) view on records is preserved.  Potential
  1373 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1374 old record representation. The type generated for a record is called
  1375 <record_name>_ext_type.
  1376 
  1377 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1378 proofs triggered by a record definition or a simproc (if
  1379 quick_and_dirty is enabled).  Definitions of large records can take
  1380 quite long.
  1381 
  1382 New simproc record_upd_simproc for simplification of multiple record
  1383 updates enabled by default.  Moreover, trivial updates are also
  1384 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1385 occasionally, since simplification is more powerful by default.
  1386 
  1387 * typedef: proper support for polymorphic sets, which contain extra
  1388 type-variables in the term.
  1389 
  1390 * Simplifier: automatically reasons about transitivity chains
  1391 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1392 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1393 old proofs break occasionally as simplification may now solve more
  1394 goals than previously.
  1395 
  1396 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1397 present.  Works for all partial orders (class "order"), in particular
  1398 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1399 just like y <= x.
  1400 
  1401 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1402 bound variable or a constant then the let is unfolded.  Otherwise
  1403 first a is simplified to b, and then f b is simplified to g. If
  1404 possible we abstract b from g arriving at "let x = b in h x",
  1405 otherwise we unfold the let and arrive at g.  The simproc can be
  1406 enabled/disabled by the reference use_let_simproc.  Potential
  1407 INCOMPATIBILITY since simplification is more powerful by default.
  1408 
  1409 * Classical reasoning: the meson method now accepts theorems as arguments.
  1410 
  1411 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1412 jobs to provide advice on the provability of subgoals.
  1413 
  1414 * Theory OrderedGroup and Ring_and_Field: various additions and
  1415 improvements to faciliate calculations involving equalities and
  1416 inequalities.
  1417 
  1418 The following theorems have been eliminated or modified
  1419 (INCOMPATIBILITY):
  1420 
  1421   abs_eq             now named abs_of_nonneg
  1422   abs_of_ge_0        now named abs_of_nonneg
  1423   abs_minus_eq       now named abs_of_nonpos
  1424   imp_abs_id         now named abs_of_nonneg
  1425   imp_abs_neg_id     now named abs_of_nonpos
  1426   mult_pos           now named mult_pos_pos
  1427   mult_pos_le        now named mult_nonneg_nonneg
  1428   mult_pos_neg_le    now named mult_nonneg_nonpos
  1429   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1430   mult_neg           now named mult_neg_neg
  1431   mult_neg_le        now named mult_nonpos_nonpos
  1432 
  1433 * Theory Parity: added rules for simplifying exponents.
  1434 
  1435 * Theory List:
  1436 
  1437 The following theorems have been eliminated or modified
  1438 (INCOMPATIBILITY):
  1439 
  1440   list_all_Nil       now named list_all.simps(1)
  1441   list_all_Cons      now named list_all.simps(2)
  1442   list_all_conv      now named list_all_iff
  1443   set_mem_eq         now named mem_iff
  1444 
  1445 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1446 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1447 
  1448 
  1449 *** HOL-Complex ***
  1450 
  1451 * Theory RealDef: better support for embedding natural numbers and
  1452 integers in the reals.
  1453 
  1454 The following theorems have been eliminated or modified
  1455 (INCOMPATIBILITY):
  1456 
  1457   exp_ge_add_one_self  now requires no hypotheses
  1458   real_of_int_add      reversed direction of equality (use [symmetric])
  1459   real_of_int_minus    reversed direction of equality (use [symmetric])
  1460   real_of_int_diff     reversed direction of equality (use [symmetric])
  1461   real_of_int_mult     reversed direction of equality (use [symmetric])
  1462 
  1463 * Theory RComplete: expanded support for floor and ceiling functions.
  1464 
  1465 * Theory Ln is new, with properties of the natural logarithm
  1466 
  1467 * Hyperreal: There is a new type constructor "star" for making
  1468 nonstandard types.  The old type names are now type synonyms:
  1469 
  1470   hypreal = real star
  1471   hypnat = nat star
  1472   hcomplex = complex star
  1473 
  1474 * Hyperreal: Many groups of similarly-defined constants have been
  1475 replaced by polymorphic versions (INCOMPATIBILITY):
  1476 
  1477   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1478 
  1479   starset      <-- starsetNat, starsetC
  1480   *s*          <-- *sNat*, *sc*
  1481   starset_n    <-- starsetNat_n, starsetC_n
  1482   *sn*         <-- *sNatn*, *scn*
  1483   InternalSets <-- InternalNatSets, InternalCSets
  1484 
  1485   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1486   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1487   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1488   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1489   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1490 
  1491 * Hyperreal: Many type-specific theorems have been removed in favor of
  1492 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1493 
  1494   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1495   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1496   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1497   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1498   right_minus <-- hypreal_add_minus
  1499   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1500   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1501   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1502   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1503   mult_1_right <-- hcomplex_mult_one_right
  1504   mult_zero_left <-- hcomplex_mult_zero_left
  1505   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1506   right_distrib <-- hypnat_add_mult_distrib2
  1507   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1508   right_inverse <-- hypreal_mult_inverse
  1509   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1510   order_refl <-- {hypreal,hypnat}_le_refl
  1511   order_trans <-- {hypreal,hypnat}_le_trans
  1512   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1513   order_less_le <-- {hypreal,hypnat}_less_le
  1514   linorder_linear <-- {hypreal,hypnat}_le_linear
  1515   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1516   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1517   add_nonneg_nonneg <-- hypreal_le_add_order
  1518 
  1519 * Hyperreal: Separate theorems having to do with type-specific
  1520 versions of constants have been merged into theorems that apply to the
  1521 new polymorphic constants (INCOMPATIBILITY):
  1522 
  1523   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1524   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1525   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1526   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1527   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1528   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1529   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1530   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1531   STAR_diff <-- {STAR,STARC}_diff
  1532   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1533     STARC_hcomplex_of_complex}_image_subset
  1534   starset_n_Un <-- starset{Nat,C}_n_Un
  1535   starset_n_Int <-- starset{Nat,C}_n_Int
  1536   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1537   starset_n_diff <-- starset{Nat,C}_n_diff
  1538   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1539   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1540   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1541   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1542   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1543   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1544   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1545   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1546   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1547   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1548   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1549   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1550   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1551   starfun_diff <-- starfun{C,RC,CR}_diff
  1552   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1553   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1554   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1555   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1556   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1557   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1558   starfun_Id <-- starfunC_Id
  1559   starfun_approx <-- starfun{Nat,CR}_approx
  1560   starfun_capprox <-- starfun{C,RC}_capprox
  1561   starfun_abs <-- starfunNat_rabs
  1562   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1563   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1564   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1565   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1566   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1567   starfun_add_approx <-- starfunCR_add_approx
  1568   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1569   starfun_divide <-- starfun{C,CR,RC}_divide
  1570   starfun_n <-- starfun{Nat,C}_n
  1571   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1572   starfun_n_add <-- starfun{Nat,C}_n_add
  1573   starfun_n_add_minus <-- starfunNat_n_add_minus
  1574   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1575   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1576   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1577 
  1578   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1579   star_n_minus <-- {hypreal,hcomplex}_minus
  1580   star_n_diff <-- {hypreal,hcomplex}_diff
  1581   star_n_mult <-- {hypreal,hcomplex}_mult
  1582   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1583   star_n_le <-- {hypreal,hypnat}_le
  1584   star_n_less <-- {hypreal,hypnat}_less
  1585   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1586   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1587   star_n_abs <-- hypreal_hrabs
  1588   star_n_divide <-- hcomplex_divide
  1589 
  1590   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1591   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1592   star_of_diff <-- hypreal_of_real_diff
  1593   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1594   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1595   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1596   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1597   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1598   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1599   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1600   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1601   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1602   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1603   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1604   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1605   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1606   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1607   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1608   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1609   star_of_power <-- hypreal_of_real_power
  1610   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1611 
  1612 * Hyperreal: new method "transfer" that implements the transfer
  1613 principle of nonstandard analysis. With a subgoal that mentions
  1614 nonstandard types like "'a star", the command "apply transfer"
  1615 replaces it with an equivalent one that mentions only standard types.
  1616 To be successful, all free variables must have standard types; non-
  1617 standard variables must have explicit universal quantifiers.
  1618 
  1619 * Hyperreal: A theory of Taylor series.
  1620 
  1621 
  1622 *** HOLCF ***
  1623 
  1624 * Discontinued special version of 'constdefs' (which used to support
  1625 continuous functions) in favor of the general Pure one with full
  1626 type-inference.
  1627 
  1628 * New simplification procedure for solving continuity conditions; it
  1629 is much faster on terms with many nested lambda abstractions (cubic
  1630 instead of exponential time).
  1631 
  1632 * New syntax for domain package: selector names are now optional.
  1633 Parentheses should be omitted unless argument is lazy, for example:
  1634 
  1635   domain 'a stream = cons "'a" (lazy "'a stream")
  1636 
  1637 * New command 'fixrec' for defining recursive functions with pattern
  1638 matching; defining multiple functions with mutual recursion is also
  1639 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1640 sinr, or any data constructor defined by the domain package. The given
  1641 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1642 syntax and examples.
  1643 
  1644 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1645 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1646 but the proof obligation additionally includes an admissibility
  1647 requirement. The packages generate instances of class cpo or pcpo,
  1648 with continuity and strictness theorems for Rep and Abs.
  1649 
  1650 * HOLCF: Many theorems have been renamed according to a more standard naming
  1651 scheme (INCOMPATIBILITY):
  1652 
  1653   foo_inject:  "foo$x = foo$y ==> x = y"
  1654   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1655   foo_less:    "(foo$x << foo$y) = (x << y)"
  1656   foo_strict:  "foo$UU = UU"
  1657   foo_defined: "... ==> foo$x ~= UU"
  1658   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1659 
  1660 
  1661 *** ZF ***
  1662 
  1663 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1664 including the First Isomorphism Theorem (on quotienting by the kernel
  1665 of a homomorphism).
  1666 
  1667 * ZF/Simplifier: install second copy of type solver that actually
  1668 makes use of TC rules declared to Isar proof contexts (or locales);
  1669 the old version is still required for ML proof scripts.
  1670 
  1671 
  1672 *** Cube ***
  1673 
  1674 * Converted to Isar theory format; use locales instead of axiomatic
  1675 theories.
  1676 
  1677 
  1678 *** ML ***
  1679 
  1680 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1681 for ||>, ||>>, |>>,
  1682 
  1683 * Pure/library.ML no longer defines its own option datatype, but uses
  1684 that of the SML basis, which has constructors NONE and SOME instead of
  1685 None and Some, as well as exception Option.Option instead of OPTION.
  1686 The functions the, if_none, is_some, is_none have been adapted
  1687 accordingly, while Option.map replaces apsome.
  1688 
  1689 * Pure/library.ML: the exception LIST has been given up in favour of
  1690 the standard exceptions Empty and Subscript, as well as
  1691 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1692 superceded by the standard hd and tl functions etc.
  1693 
  1694 A number of basic list functions are no longer exported to the ML
  1695 toplevel, as they are variants of predefined functions.  The following
  1696 suggests how one can translate existing code:
  1697 
  1698     rev_append xs ys = List.revAppend (xs, ys)
  1699     nth_elem (i, xs) = List.nth (xs, i)
  1700     last_elem xs = List.last xs
  1701     flat xss = List.concat xss
  1702     seq fs = List.app fs
  1703     partition P xs = List.partition P xs
  1704     mapfilter f xs = List.mapPartial f xs
  1705 
  1706 * Pure/library.ML: several combinators for linear functional
  1707 transformations, notably reverse application and composition:
  1708 
  1709   x |> f                f #> g
  1710   (x, y) |-> f          f #-> g
  1711 
  1712 * Pure/library.ML: introduced/changed precedence of infix operators:
  1713 
  1714   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1715   infix 2 ?;
  1716   infix 3 o oo ooo oooo;
  1717   infix 4 ~~ upto downto;
  1718 
  1719 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1720 infix operators.
  1721 
  1722 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1723 fold_map support linear functional transformations and nesting.  For
  1724 example:
  1725 
  1726   fold f [x1, ..., xN] y =
  1727     y |> f x1 |> ... |> f xN
  1728 
  1729   (fold o fold) f [xs1, ..., xsN] y =
  1730     y |> fold f xs1 |> ... |> fold f xsN
  1731 
  1732   fold f [x1, ..., xN] =
  1733     f x1 #> ... #> f xN
  1734 
  1735   (fold o fold) f [xs1, ..., xsN] =
  1736     fold f xs1 #> ... #> fold f xsN
  1737 
  1738 * Pure/library.ML: the following selectors on type 'a option are
  1739 available:
  1740 
  1741   the:               'a option -> 'a  (*partial*)
  1742   these:             'a option -> 'a  where 'a = 'b list
  1743   the_default: 'a -> 'a option -> 'a
  1744   the_list:          'a option -> 'a list
  1745 
  1746 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1747 basic operations for association lists, following natural argument
  1748 order; moreover the explicit equality predicate passed here avoids
  1749 potentially expensive polymorphic runtime equality checks.
  1750 The old functions may be expressed as follows:
  1751 
  1752   assoc = uncurry (AList.lookup (op =))
  1753   assocs = these oo AList.lookup (op =)
  1754   overwrite = uncurry (AList.update (op =)) o swap
  1755 
  1756 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1757 
  1758   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1759   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1760 
  1761 replacing make_keylist and keyfilter (occassionally used)
  1762 Naive rewrites:
  1763 
  1764   make_keylist = AList.make
  1765   keyfilter = AList.find (op =)
  1766 
  1767 * eq_fst and eq_snd now take explicit equality parameter, thus
  1768   avoiding eqtypes. Naive rewrites:
  1769 
  1770     eq_fst = eq_fst (op =)
  1771     eq_snd = eq_snd (op =)
  1772 
  1773 * Removed deprecated apl and apr (rarely used).
  1774   Naive rewrites:
  1775 
  1776     apl (n, op) =>>= curry op n
  1777     apr (op, m) =>>= fn n => op (n, m)
  1778 
  1779 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1780 provides a reasonably efficient light-weight implementation of sets as
  1781 lists.
  1782 
  1783 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1784 few new operations; existing lookup and update are now curried to
  1785 follow natural argument order (for use with fold etc.);
  1786 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1787 
  1788 * Pure/General: output via the Isabelle channels of
  1789 writeln/warning/error etc. is now passed through Output.output, with a
  1790 hook for arbitrary transformations depending on the print_mode
  1791 (cf. Output.add_mode -- the first active mode that provides a output
  1792 function wins).  Already formatted output may be embedded into further
  1793 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1794 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1795 accommodate easy composition of diagnostic messages etc.  Programmers
  1796 rarely need to care about Output.output or Output.raw at all, with
  1797 some notable exceptions: Output.output is required when bypassing the
  1798 standard channels (writeln etc.), or in token translations to produce
  1799 properly formatted results; Output.raw is required when capturing
  1800 already output material that will eventually be presented to the user
  1801 a second time.  For the default print mode, both Output.output and
  1802 Output.raw have no effect.
  1803 
  1804 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1805 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1806 cumulative results are displayed at the end of a batch session.
  1807 
  1808 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1809 replaced by File.platform_path and File.shell_path (with appropriate
  1810 hooks).  This provides a clean interface for unusual systems where the
  1811 internal and external process view of file names are different.
  1812 
  1813 * Pure: more efficient orders for basic syntactic entities: added
  1814 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1815 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1816 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1817 orders now -- potential INCOMPATIBILITY for code that depends on a
  1818 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1819 Library.sort_strings on result).
  1820 
  1821 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1822 fold_types traverse types/terms from left to right, observing natural
  1823 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1824 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1825 
  1826 * Pure: name spaces have been refined, with significant changes of the
  1827 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1828 to extern(_table).  The plain name entry path is superceded by a
  1829 general 'naming' context, which also includes the 'policy' to produce
  1830 a fully qualified name and external accesses of a fully qualified
  1831 name; NameSpace.extend is superceded by context dependent
  1832 Sign.declare_name.  Several theory and proof context operations modify
  1833 the naming context.  Especially note Theory.restore_naming and
  1834 ProofContext.restore_naming to get back to a sane state; note that
  1835 Theory.add_path is no longer sufficient to recover from
  1836 Theory.absolute_path in particular.
  1837 
  1838 * Pure: new flags short_names (default false) and unique_names
  1839 (default true) for controlling output of qualified names.  If
  1840 short_names is set, names are printed unqualified.  If unique_names is
  1841 reset, the name prefix is reduced to the minimum required to achieve
  1842 the original result when interning again, even if there is an overlap
  1843 with earlier declarations.
  1844 
  1845 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1846 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1847 (useful for printing error messages).  INCOMPATIBILITY.
  1848 
  1849 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1850 Theory.theory are now identified, referring to the universal
  1851 Context.theory (see Pure/context.ML).  Actual signature and theory
  1852 content is managed as theory data.  The old code and interfaces were
  1853 spread over many files and structures; the new arrangement introduces
  1854 considerable INCOMPATIBILITY to gain more clarity:
  1855 
  1856   Context -- theory management operations (name, identity, inclusion,
  1857     parents, ancestors, merge, etc.), plus generic theory data;
  1858 
  1859   Sign -- logical signature and syntax operations (declaring consts,
  1860     types, etc.), plus certify/read for common entities;
  1861 
  1862   Theory -- logical theory operations (stating axioms, definitions,
  1863     oracles), plus a copy of logical signature operations (consts,
  1864     types, etc.); also a few basic management operations (Theory.copy,
  1865     Theory.merge, etc.)
  1866 
  1867 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1868 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1869 for convenience -- they merely return the theory.
  1870 
  1871 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1872 
  1873 * Pure: the Isar proof context type is already defined early in Pure
  1874 as Context.proof (note that ProofContext.context and Proof.context are
  1875 aliases, where the latter is the preferred name).  This enables other
  1876 Isabelle components to refer to that type even before Isar is present.
  1877 
  1878 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1879 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1880 any of these kinds.  For example, Sign.intern typeK is now
  1881 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1882 Theory.hide_types.  Also note that former
  1883 Theory.hide_classes/types/consts are now
  1884 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1885 internalize their arguments!  INCOMPATIBILITY.
  1886 
  1887 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1888 datatype thmref (with constructors Name and NameSelection) instead of
  1889 plain string -- INCOMPATIBILITY;
  1890 
  1891 * Pure: cases produced by proof methods specify options, where NONE
  1892 means to remove case bindings -- INCOMPATIBILITY in
  1893 (RAW_)METHOD_CASES.
  1894 
  1895 * Pure: the following operations retrieve axioms or theorems from a
  1896 theory node or theory hierarchy, respectively:
  1897 
  1898   Theory.axioms_of: theory -> (string * term) list
  1899   Theory.all_axioms_of: theory -> (string * term) list
  1900   PureThy.thms_of: theory -> (string * thm) list
  1901   PureThy.all_thms_of: theory -> (string * thm) list
  1902 
  1903 * Pure: print_tac now outputs the goal through the trace channel.
  1904 
  1905 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1906 Reference Toplevel.debug (default false) controls detailed printing
  1907 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1908 controls execution profiling -- set to 1 for time and 2 for space
  1909 (both increase the runtime).
  1910 
  1911 * Isar session: The initial use of ROOT.ML is now always timed,
  1912 i.e. the log will show the actual process times, in contrast to the
  1913 elapsed wall-clock time that the outer shell wrapper produces.
  1914 
  1915 * Simplifier: improved handling of bound variables (nameless
  1916 representation, avoid allocating new strings).  Simprocs that invoke
  1917 the Simplifier recursively should use Simplifier.inherit_bounds to
  1918 avoid local name clashes.  Failure to do so produces warnings
  1919 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1920 for further details.
  1921 
  1922 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1923 bindings for all theorems stored within a given theory; this may help
  1924 in porting non-Isar theories to Isar ones, while keeping ML proof
  1925 scripts for the time being.
  1926 
  1927 * ML operator HTML.with_charset specifies the charset begin used for
  1928 generated HTML files.  For example:
  1929 
  1930   HTML.with_charset "utf-8" use_thy "Hebrew";
  1931   HTML.with_charset "utf-8" use_thy "Chinese";
  1932 
  1933 
  1934 *** System ***
  1935 
  1936 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1937 isabelle, isatool etc.).
  1938 
  1939 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1940 isatool doc, isatool mkdir, display_drafts etc.).
  1941 
  1942 * isatool usedir: option -f allows specification of the ML file to be
  1943 used by Isabelle; default is ROOT.ML.
  1944 
  1945 * New isatool version outputs the version identifier of the Isabelle
  1946 distribution being used.
  1947 
  1948 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1949 (containing Boolean satisfiability problems) into Isabelle/HOL
  1950 theories.
  1951 
  1952 
  1953 
  1954 New in Isabelle2004 (April 2004)
  1955 --------------------------------
  1956 
  1957 *** General ***
  1958 
  1959 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1960   Replaces linorder.ML.
  1961 
  1962 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1963   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1964   (\<a>...\<z>), are now considered normal letters, and can therefore
  1965   be used anywhere where an ASCII letter (a...zA...Z) has until
  1966   now. COMPATIBILITY: This obviously changes the parsing of some
  1967   terms, especially where a symbol has been used as a binder, say
  1968   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1969   as an identifier.  Fix it by inserting a space around former
  1970   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1971   existing theory and ML files.
  1972 
  1973 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1974 
  1975 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1976   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1977   a normal (but invisible) letter. For multiple letter subscripts repeat
  1978   \<^isub> like this: x\<^isub>1\<^isub>2.
  1979 
  1980 * Pure: There are now sub-/superscripts that can span more than one
  1981   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1982   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1983   superscript. The new control characters are not identifier parts.
  1984 
  1985 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1986   content of "..." to the latex file instead of \isacntrl... . The "..."
  1987   may consist of any printable characters excluding the end bracket >.
  1988 
  1989 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1990   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1991   declare constants "final", which prevents their being given a definition
  1992   later.  It is useful for constants whose behaviour is fixed axiomatically
  1993   rather than definitionally, such as the meta-logic connectives.
  1994 
  1995 * Pure: 'instance' now handles general arities with general sorts
  1996   (i.e. intersections of classes),
  1997 
  1998 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1999   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2000   It can be changed to alter the colors/layout of generated pages.
  2001 
  2002 
  2003 *** Isar ***
  2004 
  2005 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2006   cut_tac, subgoal_tac and thin_tac:
  2007   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2008     locales are no longer forced to write Isar proof scripts.
  2009     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2010     emulations.
  2011   - INCOMPATIBILITY: names of variables to be instantiated may no
  2012     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2013     This is consistent with the instantiation attribute "where".
  2014 
  2015 * Attributes "where" and "of":
  2016   - Now take type variables of instantiated theorem into account when reading
  2017     the instantiation string.  This fixes a bug that caused instantiated
  2018     theorems to have too special types in some circumstances.
  2019   - "where" permits explicit instantiations of type variables.
  2020 
  2021 * Calculation commands "moreover" and "also" no longer interfere with
  2022   current facts ("this"), admitting arbitrary combinations with "then"
  2023   and derived forms.
  2024 
  2025 * Locales:
  2026   - Goal statements involving the context element "includes" no longer
  2027     generate theorems with internal delta predicates (those ending on
  2028     "_axioms") in the premise.
  2029     Resolve particular premise with <locale>.intro to obtain old form.
  2030   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2031     specification and "includes" elements in goal statement.
  2032   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2033     [intro?] and [elim?] (respectively) by default.
  2034   - Experimental command for instantiation of locales in proof contexts:
  2035         instantiate <label>[<attrs>]: <loc>
  2036     Instantiates locale <loc> and adds all its theorems to the current context
  2037     taking into account their attributes.  Label and attrs are optional
  2038     modifiers, like in theorem declarations.  If present, names of
  2039     instantiated theorems are qualified with <label>, and the attributes
  2040     <attrs> are applied after any attributes these theorems might have already.
  2041       If the locale has assumptions, a chained fact of the form
  2042     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2043     are derived.  The command does not support old-style locales declared
  2044     with "locale (open)".
  2045       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2046 
  2047 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2048   (Isar) contexts.
  2049 
  2050 
  2051 *** HOL ***
  2052 
  2053 * Proof import: new image HOL4 contains the imported library from
  2054   the HOL4 system with about 2500 theorems. It is imported by
  2055   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2056   can be used like any other Isabelle image.  See
  2057   HOL/Import/HOL/README for more information.
  2058 
  2059 * Simplifier:
  2060   - Much improved handling of linear and partial orders.
  2061     Reasoners for linear and partial orders are set up for type classes
  2062     "linorder" and "order" respectively, and are added to the default simpset
  2063     as solvers.  This means that the simplifier can build transitivity chains
  2064     to solve goals from the assumptions.
  2065   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2066     of blast or auto after simplification become unnecessary because the goal
  2067     is solved by simplification already.
  2068 
  2069 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2070     all proved in axiomatic type classes for semirings, rings and fields.
  2071 
  2072 * Numerics:
  2073   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2074     now formalized using the Ring_and_Field theory mentioned above.
  2075   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2076     than before, because now they are set up once in a generic manner.
  2077   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2078     Look for the general versions in Ring_and_Field (and Power if they concern
  2079     exponentiation).
  2080 
  2081 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2082 
  2083 * Records:
  2084   - Record types are now by default printed with their type abbreviation
  2085     instead of the list of all field types. This can be configured via
  2086     the reference "print_record_type_abbr".
  2087   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2088     (not enabled by default).
  2089   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2090     EX x. x = sel r to True (not enabled by default).
  2091   - Tactic "record_split_simp_tac" to split and simplify records added.
  2092 
  2093 * 'specification' command added, allowing for definition by
  2094   specification.  There is also an 'ax_specification' command that
  2095   introduces the new constants axiomatically.
  2096 
  2097 * arith(_tac) is now able to generate counterexamples for reals as well.
  2098 
  2099 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2100 
  2101 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2102   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2103 
  2104 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2105   matrix theory to linear programming.
  2106 
  2107 * Unions and Intersections:
  2108   The latex output syntax of UN and INT has been changed
  2109   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2110   i.e. the index formulae has become a subscript.
  2111   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2112 
  2113 * Unions and Intersections over Intervals:
  2114   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2115   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2116   like in normal math, and corresponding versions for < and for intersection.
  2117 
  2118 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2119   lexicographic dictonary ordering has been added as "lexord".
  2120 
  2121 * ML: the legacy theory structures Int and List have been removed. They had
  2122   conflicted with ML Basis Library structures having the same names.
  2123 
  2124 * 'refute' command added to search for (finite) countermodels.  Only works
  2125   for a fragment of HOL.  The installation of an external SAT solver is
  2126   highly recommended.  See "HOL/Refute.thy" for details.
  2127 
  2128 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2129   formulae under an assignment of free variables to random values.
  2130   In contrast to 'refute', it can deal with inductive datatypes,
  2131   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2132   for examples.
  2133 
  2134 
  2135 *** HOLCF ***
  2136 
  2137 * Streams now come with concatenation and are part of the HOLCF image
  2138 
  2139 
  2140 
  2141 New in Isabelle2003 (May 2003)
  2142 ------------------------------
  2143 
  2144 *** General ***
  2145 
  2146 * Provers/simplifier:
  2147 
  2148   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2149     Assumptions are now subject to complete mutual simplification,
  2150     not just from left to right. The simplifier now preserves
  2151     the order of assumptions.
  2152 
  2153     Potential INCOMPATIBILITY:
  2154 
  2155     -- simp sometimes diverges where the old version did
  2156        not, e.g. invoking simp on the goal
  2157 
  2158         [| P (f x); y = x; f x = f y |] ==> Q
  2159 
  2160        now gives rise to the infinite reduction sequence
  2161 
  2162         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2163 
  2164        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2165        kind of problem.
  2166 
  2167     -- Tactics combining classical reasoner and simplification (such as auto)
  2168        are also affected by this change, because many of them rely on
  2169        simp. They may sometimes diverge as well or yield a different numbers
  2170        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2171        in case of problems. Sometimes subsequent calls to the classical
  2172        reasoner will fail because a preceeding call to the simplifier too
  2173        eagerly simplified the goal, e.g. deleted redundant premises.
  2174 
  2175   - The simplifier trace now shows the names of the applied rewrite rules
  2176 
  2177   - You can limit the number of recursive invocations of the simplifier
  2178     during conditional rewriting (where the simplifie tries to solve the
  2179     conditions before applying the rewrite rule):
  2180     ML "simp_depth_limit := n"
  2181     where n is an integer. Thus you can force termination where previously
  2182     the simplifier would diverge.
  2183 
  2184   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2185 
  2186   - No longer aborts on failed congruence proof.  Instead, the
  2187     congruence is ignored.
  2188 
  2189 * Pure: New generic framework for extracting programs from constructive
  2190   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2191   as HOL/Extraction for some case studies.
  2192 
  2193 * Pure: The main goal of the proof state is no longer shown by default, only
  2194 the subgoals. This behaviour is controlled by a new flag.
  2195    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2196 (ML: Proof.show_main_goal).
  2197 
  2198 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2199 rules whose conclusion matches subgoal 1:
  2200       PG menu: Isabelle/Isar -> Show me -> matching rules
  2201 The rules are ordered by how closely they match the subgoal.
  2202 In particular, rules that solve a subgoal outright are displayed first
  2203 (or rather last, the way they are printed).
  2204 (ML: ProofGeneral.print_intros())
  2205 
  2206 * Pure: New flag trace_unify_fail causes unification to print
  2207 diagnostic information (PG: in trace buffer) when it fails. This is
  2208 useful for figuring out why single step proofs like rule, erule or
  2209 assumption failed.
  2210 
  2211 * Pure: Locale specifications now produce predicate definitions
  2212 according to the body of text (covering assumptions modulo local
  2213 definitions); predicate "loc_axioms" covers newly introduced text,
  2214 while "loc" is cumulative wrt. all included locale expressions; the
  2215 latter view is presented only on export into the global theory
  2216 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2217 on the old view without predicates;
  2218 
  2219 * Pure: predefined locales "var" and "struct" are useful for sharing
  2220 parameters (as in CASL, for example); just specify something like
  2221 ``var x + var y + struct M'' as import;
  2222 
  2223 * Pure: improved thms_containing: proper indexing of facts instead of
  2224 raw theorems; check validity of results wrt. current name space;
  2225 include local facts of proof configuration (also covers active
  2226 locales), cover fixed variables in index; may use "_" in term
  2227 specification; an optional limit for the number of printed facts may
  2228 be given (the default is 40);
  2229 
  2230 * Pure: disallow duplicate fact bindings within new-style theory files
  2231 (batch-mode only);
  2232 
  2233 * Provers: improved induct method: assumptions introduced by case
  2234 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2235 the goal statement); "foo" still refers to all facts collectively;
  2236 
  2237 * Provers: the function blast.overloaded has been removed: all constants
  2238 are regarded as potentially overloaded, which improves robustness in exchange
  2239 for slight decrease in efficiency;
  2240 
  2241 * Provers/linorder: New generic prover for transitivity reasoning over
  2242 linear orders.  Note: this prover is not efficient!
  2243 
  2244 * Isar: preview of problems to finish 'show' now produce an error
  2245 rather than just a warning (in interactive mode);
  2246 
  2247 
  2248 *** HOL ***
  2249 
  2250 * arith(_tac)
  2251 
  2252  - Produces a counter example if it cannot prove a goal.
  2253    Note that the counter example may be spurious if the goal is not a formula
  2254    of quantifier-free linear arithmetic.
  2255    In ProofGeneral the counter example appears in the trace buffer.
  2256 
  2257  - Knows about div k and mod k where k is a numeral of type nat or int.
  2258 
  2259  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2260    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2261    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2262 
  2263 * simp's arithmetic capabilities have been enhanced a bit: it now
  2264 takes ~= in premises into account (by performing a case split);
  2265 
  2266 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2267 are distributed over a sum of terms;
  2268 
  2269 * New tactic "trans_tac" and method "trans" instantiate
  2270 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2271 "<=", "<" and "=").
  2272 
  2273 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2274 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2275 
  2276 * 'typedef' command has new option "open" to suppress the set
  2277 definition;
  2278 
  2279 * functions Min and Max on finite sets have been introduced (theory
  2280 Finite_Set);
  2281 
  2282 * attribute [symmetric] now works for relations as well; it turns
  2283 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2284 
  2285 * induct over a !!-quantified statement (say !!x1..xn):
  2286   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2287 
  2288 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2289 %x. None. Warning: empty_def now refers to the previously hidden definition
  2290 of the empty set.
  2291 
  2292 * Algebra: formalization of classical algebra.  Intended as base for
  2293 any algebraic development in Isabelle.  Currently covers group theory
  2294 (up to Sylow's theorem) and ring theory (Universal Property of
  2295 Univariate Polynomials).  Contributions welcome;
  2296 
  2297 * GroupTheory: deleted, since its material has been moved to Algebra;
  2298 
  2299 * Complex: new directory of the complex numbers with numeric constants,
  2300 nonstandard complex numbers, and some complex analysis, standard and
  2301 nonstandard (Jacques Fleuriot);
  2302 
  2303 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2304 
  2305 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2306 Fleuriot);
  2307 
  2308 * Real/HahnBanach: updated and adapted to locales;
  2309 
  2310 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2311 Gray and Kramer);
  2312 
  2313 * UNITY: added the Meier-Sanders theory of progress sets;
  2314 
  2315 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2316 as abstract algorithms, instantiated to the JVM;
  2317 
  2318 * Bali: Java source language formalization. Type system, operational
  2319 semantics, axiomatic semantics. Supported language features:
  2320 classes, interfaces, objects,virtual methods, static methods,
  2321 static/instance fields, arrays, access modifiers, definite
  2322 assignment, exceptions.
  2323 
  2324 
  2325 *** ZF ***
  2326 
  2327 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2328 universe, etc.);
  2329 
  2330 * Main ZF: virtually all theories converted to new-style format;
  2331 
  2332 
  2333 *** ML ***
  2334 
  2335 * Pure: Tactic.prove provides sane interface for internal proofs;
  2336 omits the infamous "standard" operation, so this is more appropriate
  2337 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2338 
  2339 * Pure: improved error reporting of simprocs;
  2340 
  2341 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2342 up simprocs;
  2343 
  2344 
  2345 *** Document preparation ***
  2346 
  2347 * uses \par instead of \\ for line breaks in theory text. This may
  2348 shift some page breaks in large documents. To get the old behaviour
  2349 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2350 
  2351 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2352 other packages
  2353 
  2354 * \<euro> now needs package babel/greek instead of marvosym (which
  2355 broke \Rightarrow)
  2356 
  2357 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2358 textcomp package)
  2359 
  2360 
  2361 
  2362 New in Isabelle2002 (March 2002)
  2363 --------------------------------
  2364 
  2365 *** Document preparation ***
  2366 
  2367 * greatly simplified document preparation setup, including more
  2368 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2369 instructive isatool mkdir; users should basically be able to get
  2370 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2371 users may run a separate document processing stage manually like this:
  2372 "isatool usedir -D output HOL Test && isatool document Test/output";
  2373 
  2374 * theory dependency graph may now be incorporated into documents;
  2375 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2376 with \includegraphics of LaTeX;
  2377 
  2378 * proper spacing of consecutive markup elements, especially text
  2379 blocks after section headings;
  2380 
  2381 * support bold style (for single symbols only), input syntax is like
  2382 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2383 
  2384 * \<bullet> is now output as bold \cdot by default, which looks much
  2385 better in printed text;
  2386 
  2387 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2388 note that these symbols are currently unavailable in Proof General /
  2389 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2390 
  2391 * isatool latex no longer depends on changed TEXINPUTS, instead
  2392 isatool document copies the Isabelle style files to the target
  2393 location;
  2394 
  2395 
  2396 *** Isar ***
  2397 
  2398 * Pure/Provers: improved proof by cases and induction;
  2399   - 'case' command admits impromptu naming of parameters (such as
  2400     "case (Suc n)");
  2401   - 'induct' method divinates rule instantiation from the inductive
  2402     claim; no longer requires excessive ?P bindings for proper
  2403     instantiation of cases;
  2404   - 'induct' method properly enumerates all possibilities of set/type
  2405     rules; as a consequence facts may be also passed through *type*
  2406     rules without further ado;
  2407   - 'induct' method now derives symbolic cases from the *rulified*
  2408     rule (before it used to rulify cases stemming from the internal
  2409     atomized version); this means that the context of a non-atomic
  2410     statement becomes is included in the hypothesis, avoiding the
  2411     slightly cumbersome show "PROP ?case" form;
  2412   - 'induct' may now use elim-style induction rules without chaining
  2413     facts, using ``missing'' premises from the goal state; this allows
  2414     rules stemming from inductive sets to be applied in unstructured
  2415     scripts, while still benefitting from proper handling of non-atomic
  2416     statements; NB: major inductive premises need to be put first, all
  2417     the rest of the goal is passed through the induction;
  2418   - 'induct' proper support for mutual induction involving non-atomic
  2419     rule statements (uses the new concept of simultaneous goals, see
  2420     below);
  2421   - append all possible rule selections, but only use the first
  2422     success (no backtracking);
  2423   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2424   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2425   - added 'print_induct_rules' (covered by help item in recent Proof
  2426     General versions);
  2427   - moved induct/cases attributes to Pure, methods to Provers;
  2428   - generic method setup instantiated for FOL and HOL;
  2429 
  2430 * Pure: support multiple simultaneous goal statements, for example
  2431 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2432 meta-level mechanism, this acts as if several individual goals had
  2433 been stated separately; in particular common proof methods need to be
  2434 repeated in order to cover all claims; note that a single elimination
  2435 step is *not* sufficient to establish the two conjunctions, so this
  2436 fails:
  2437 
  2438   assume "A & B" then have A and B ..   (*".." fails*)
  2439 
  2440 better use "obtain" in situations as above; alternative refer to
  2441 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2442 
  2443 * Pure: proper integration with ``locales''; unlike the original
  2444 version by Florian Kammller, Isar locales package high-level proof
  2445 contexts rather than raw logical ones (e.g. we admit to include
  2446 attributes everywhere); operations on locales include merge and
  2447 rename; support for implicit arguments (``structures''); simultaneous
  2448 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2449 some examples;
  2450 
  2451 * Pure: the following commands have been ``localized'', supporting a
  2452 target locale specification "(in name)": 'lemma', 'theorem',
  2453 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2454 stored both within the locale and at the theory level (exported and
  2455 qualified by the locale name);
  2456 
  2457 * Pure: theory goals may now be specified in ``long'' form, with
  2458 ad-hoc contexts consisting of arbitrary locale elements. for example
  2459 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2460 definitions may be given, too); the result is a meta-level rule with
  2461 the context elements being discharged in the obvious way;
  2462 
  2463 * Pure: new proof command 'using' allows to augment currently used
  2464 facts after a goal statement ('using' is syntactically analogous to
  2465 'apply', but acts on the goal's facts only); this allows chained facts
  2466 to be separated into parts given before and after a claim, as in
  2467 ``from a and b have C using d and e <proof>'';
  2468 
  2469 * Pure: renamed "antecedent" case to "rule_context";
  2470 
  2471 * Pure: new 'judgment' command records explicit information about the
  2472 object-logic embedding (used by several tools internally); no longer
  2473 use hard-wired "Trueprop";
  2474 
  2475 * Pure: added 'corollary' command;
  2476 
  2477 * Pure: fixed 'token_translation' command;
  2478 
  2479 * Pure: removed obsolete 'exported' attribute;
  2480 
  2481 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2482 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2483 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2484 
  2485 * Pure: method 'atomize' presents local goal premises as object-level
  2486 statements (atomic meta-level propositions); setup controlled via
  2487 rewrite rules declarations of 'atomize' attribute; example
  2488 application: 'induct' method with proper rule statements in improper
  2489 proof *scripts*;
  2490 
  2491 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2492 now consider the syntactic context of assumptions, giving a better
  2493 chance to get type-inference of the arguments right (this is
  2494 especially important for locales);
  2495 
  2496 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2497 mode;
  2498 
  2499 * Pure/obtain: the formal conclusion "thesis", being marked as
  2500 ``internal'', may no longer be reference directly in the text;
  2501 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2502 situations;
  2503 
  2504 * Pure: generic 'sym' attribute which declares a rule both as pure
  2505 'elim?' and for the 'symmetric' operation;
  2506 
  2507 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2508 text; the fixed correlation with particular command syntax has been
  2509 discontinued;
  2510 
  2511 * Pure: new method 'rules' is particularly well-suited for proof
  2512 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2513 but often produces more compact proof terms with less detours;
  2514 
  2515 * Pure/Provers/classical: simplified integration with pure rule
  2516 attributes and methods; the classical "intro?/elim?/dest?"
  2517 declarations coincide with the pure ones; the "rule" method no longer
  2518 includes classically swapped intros; "intro" and "elim" methods no
  2519 longer pick rules from the context; also got rid of ML declarations
  2520 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2521 INCOMPATIBILITY;
  2522 
  2523 * Provers/classical: attribute 'swapped' produces classical inversions
  2524 of introduction rules;
  2525 
  2526 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2527 rules instead of full simplifier context; 'iff' attribute handles
  2528 conditional rules;
  2529 
  2530 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2531 
  2532 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2533 "(permissive)" option to recover old behavior;
  2534 
  2535 * HOL: 'inductive' no longer features separate (collective) attributes
  2536 for 'intros' (was found too confusing);
  2537 
  2538 * HOL: properly declared induction rules less_induct and
  2539 wf_induct_rule;
  2540 
  2541 
  2542 *** HOL ***
  2543 
  2544 * HOL: moved over to sane numeral syntax; the new policy is as
  2545 follows:
  2546 
  2547   - 0 and 1 are polymorphic constants, which are defined on any
  2548   numeric type (nat, int, real etc.);
  2549 
  2550   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2551   binary representation internally;
  2552 
  2553   - type nat has special constructor Suc, and generally prefers Suc 0
  2554   over 1::nat and Suc (Suc 0) over 2::nat;
  2555 
  2556 This change may cause significant problems of INCOMPATIBILITY; here
  2557 are some hints on converting existing sources:
  2558 
  2559   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2560   entities, so expressions involving "-" (unary or binary minus) need
  2561   to be spaced properly;
  2562 
  2563   - existing occurrences of "1" may need to be constraint "1::nat" or
  2564   even replaced by Suc 0; similar for old "2";
  2565 
  2566   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2567 
  2568   - remove all special provisions on numerals in proofs;
  2569 
  2570 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2571 representation (depends on bin_arith_simps in the default context);
  2572 
  2573 * HOL: symbolic syntax for x^2 (numeral 2);
  2574 
  2575 * HOL: the class of all HOL types is now called "type" rather than
  2576 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2577 in axclass/classes, instance/arities, and (usually rare) occurrences
  2578 in typings (of consts etc.); internally the class is called
  2579 "HOL.type", ML programs should refer to HOLogic.typeS;
  2580 
  2581 * HOL/record package improvements:
  2582   - new derived operations "fields" to build a partial record section,
  2583     "extend" to promote a fixed record to a record scheme, and
  2584     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2585     declared as simp by default;
  2586   - shared operations ("more", "fields", etc.) now need to be always
  2587     qualified) --- potential INCOMPATIBILITY;
  2588   - removed "make_scheme" operations (use "make" with "extend") --
  2589     INCOMPATIBILITY;
  2590   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2591   - provides cases/induct rules for use with corresponding Isar
  2592     methods (for concrete records, record schemes, concrete more
  2593     parts, and schematic more parts -- in that order);
  2594   - internal definitions directly based on a light-weight abstract
  2595     theory of product types over typedef rather than datatype;
  2596 
  2597 * HOL: generic code generator for generating executable ML code from
  2598 specifications; specific support for HOL constructs such as inductive
  2599 datatypes and sets, as well as recursive functions; can be invoked
  2600 via 'generate_code' theory section;
  2601 
  2602 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2603 
  2604 * HOL: consolidated and renamed several theories.  In particular:
  2605         Ord.thy has been absorbed into HOL.thy
  2606         String.thy has been absorbed into List.thy
  2607 
  2608 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2609 (beware of argument permutation!);
  2610 
  2611 * HOL: linorder_less_split superseded by linorder_cases;
  2612 
  2613 * HOL/List: "nodups" renamed to "distinct";
  2614 
  2615 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2616 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2617   - Ex_def has changed, now need to use some_eq_ex
  2618 
  2619 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2620 in this (rare) case use:
  2621 
  2622   delSWrapper "split_all_tac"
  2623   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2624 
  2625 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2626 MAY FAIL;
  2627 
  2628 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2629 Isabelle's type classes, ^ on functions and relations has too general
  2630 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2631 necessary to attach explicit type constraints;
  2632 
  2633 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2634 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2635 renamed accordingly (eg "compI" -> "rel_compI").
  2636 
  2637 * HOL: syntax translations now work properly with numerals and records
  2638 expressions;
  2639 
  2640 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2641 of "lam" -- INCOMPATIBILITY;
  2642 
  2643 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2644 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2645 renamed "Product_Type.unit";
  2646 
  2647 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2648 
  2649 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2650 the "cases" method);
  2651 
  2652 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2653 Florian Kammller);
  2654 
  2655 * HOL/IMP: updated and converted to new-style theory format; several
  2656 parts turned into readable document, with proper Isar proof texts and
  2657 some explanations (by Gerwin Klein);
  2658 
  2659 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2660 
  2661 * HOL-Hyperreal is now a logic image;
  2662 
  2663 
  2664 *** HOLCF ***
  2665 
  2666 * Isar: consts/constdefs supports mixfix syntax for continuous
  2667 operations;
  2668 
  2669 * Isar: domain package adapted to new-style theory format, e.g. see
  2670 HOLCF/ex/Dnat.thy;
  2671 
  2672 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2673 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2674 lift.induct_tac, always use UU instead of Undef;
  2675 
  2676 * HOLCF/IMP: updated and converted to new-style theory;
  2677 
  2678 
  2679 *** ZF ***
  2680 
  2681 * Isar: proper integration of logic-specific tools and packages,
  2682 including theory commands '(co)inductive', '(co)datatype',
  2683 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2684 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2685 
  2686 * theory Main no longer includes AC; for the Axiom of Choice, base
  2687 your theory on Main_ZFC;
  2688 
  2689 * the integer library now covers quotients and remainders, with many
  2690 laws relating division to addition, multiplication, etc.;
  2691 
  2692 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2693 typeless version of the formalism;
  2694 
  2695 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2696 format;
  2697 
  2698 * ZF/Induct: new directory for examples of inductive definitions,
  2699 including theory Multiset for multiset orderings; converted to
  2700 new-style theory format;
  2701 
  2702 * ZF: many new theorems about lists, ordinals, etc.;
  2703 
  2704 
  2705 *** General ***
  2706 
  2707 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2708 variable proof controls level of detail: 0 = no proofs (only oracle
  2709 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2710 also ref manual for further ML interfaces;
  2711 
  2712 * Pure/axclass: removed obsolete ML interface
  2713 goal_subclass/goal_arity;
  2714 
  2715 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2716 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2717 separate tokens, so expressions involving minus need to be spaced
  2718 properly;
  2719 
  2720 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2721 rather than "infixl" or "infixr";
  2722 
  2723 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2724 sort constraint specifications in type inference; e.g. "x::_::foo"
  2725 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2726 type variable);
  2727 
  2728 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2729 control output of nested => (types); the default behavior is
  2730 "type_brackets";
  2731 
  2732 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2733 tokens into AST constants;
  2734 
  2735 * Pure/syntax: prefer later declarations of translations and print
  2736 translation functions; potential INCOMPATIBILITY: need to reverse
  2737 multiple declarations for same syntax element constant;
  2738 
  2739 * Pure/show_hyps reset by default (in accordance to existing Isar
  2740 practice);
  2741 
  2742 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2743 addSafter;
  2744 
  2745 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2746 as well;
  2747 
  2748 * system: tested support for MacOS X; should be able to get Isabelle +
  2749 Proof General to work in a plain Terminal after installing Poly/ML
  2750 (e.g. from the Isabelle distribution area) and GNU bash alone
  2751 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2752 support requires further installations, e.g. from
  2753 http://fink.sourceforge.net/);
  2754 
  2755 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2756 
  2757 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2758 of 40 MB), cf. ML_OPTIONS;
  2759 
  2760 * system: Proof General keywords specification is now part of the
  2761 Isabelle distribution (see etc/isar-keywords.el);
  2762 
  2763 * system: support for persistent Proof General sessions (refrain from
  2764 outdating all loaded theories on startup); user may create writable
  2765 logic images like this: ``isabelle -q HOL Test'';
  2766 
  2767 * system: smart selection of Isabelle process versus Isabelle
  2768 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2769 run both "isabelle" and "Isabelle" even if file names are badly
  2770 damaged (executable inspects the case of the first letter of its own
  2771 name); added separate "isabelle-process" and "isabelle-interface";
  2772 
  2773 * system: refrain from any attempt at filtering input streams; no
  2774 longer support ``8bit'' encoding of old isabelle font, instead proper
  2775 iso-latin characters may now be used; the related isatools
  2776 "symbolinput" and "nonascii" have disappeared as well;
  2777 
  2778 * system: removed old "xterm" interface (the print modes "xterm" and
  2779 "xterm_color" are still available for direct use in a suitable
  2780 terminal);
  2781 
  2782 
  2783 
  2784 New in Isabelle99-2 (February 2001)
  2785 -----------------------------------
  2786 
  2787 *** Overview of INCOMPATIBILITIES ***
  2788 
  2789 * HOL: please note that theories in the Library and elsewhere often use the
  2790 new-style (Isar) format; to refer to their theorems in an ML script you must
  2791 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2792 
  2793 * HOL: inductive package no longer splits induction rule aggressively,
  2794 but only as far as specified by the introductions given; the old
  2795 format may be recovered via ML function complete_split_rule or attribute
  2796 'split_rule (complete)';
  2797 
  2798 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2799 gfp_Tarski to gfp_unfold;
  2800 
  2801 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2802 
  2803 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2804 relation); infix "^^" has been renamed "``"; infix "``" has been
  2805 renamed "`"; "univalent" has been renamed "single_valued";
  2806 
  2807 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2808 operation;
  2809 
  2810 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2811 
  2812 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2813 
  2814 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2815 consequence, it is no longer monotonic wrt. the local goal context
  2816 (which is now passed through the inductive cases);
  2817 
  2818 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2819 \<gg> to \<ggreater>;
  2820 
  2821 
  2822 *** Document preparation ***
  2823 
  2824 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2825 available: are "it" for near math-mode best-style output, "sl" for
  2826 slanted text style, and "tt" for plain type-writer; if no
  2827 \isabellestyle command is given, output is according to slanted
  2828 type-writer);
  2829 
  2830 * support sub/super scripts (for single symbols only), input syntax is
  2831 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2832 
  2833 * some more standard symbols; see Appendix A of the system manual for
  2834 the complete list of symbols defined in isabellesym.sty;
  2835 
  2836 * improved isabelle style files; more abstract symbol implementation
  2837 (should now use \isamath{...} and \isatext{...} in custom symbol
  2838 definitions);
  2839 
  2840 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2841 state; Note that presentation of goal states does not conform to
  2842 actual human-readable proof documents.  Please do not include goal
  2843 states into document output unless you really know what you are doing!
  2844 
  2845 * proper indentation of antiquoted output with proportional LaTeX
  2846 fonts;
  2847 
  2848 * no_document ML operator temporarily disables LaTeX document
  2849 generation;
  2850 
  2851 * isatool unsymbolize tunes sources for plain ASCII communication;
  2852 
  2853 
  2854 *** Isar ***
  2855 
  2856 * Pure: Isar now suffers initial goal statements to contain unbound
  2857 schematic variables (this does not conform to actual readable proof
  2858 documents, due to unpredictable outcome and non-compositional proof
  2859 checking); users who know what they are doing may use schematic goals
  2860 for Prolog-style synthesis of proven results;
  2861 
  2862 * Pure: assumption method (an implicit finishing) now handles actual
  2863 rules as well;
  2864 
  2865 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2866 initial goal, declare "that" only as Pure intro (only for single
  2867 steps); the "that" rule assumption may now be involved in implicit
  2868 finishing, thus ".." becomes a feasible for trivial obtains;
  2869 
  2870 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2871 instance proofs may be performed by "..";
  2872 
  2873 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2874 statements as well;
  2875 
  2876 * Pure: more robust selection of calculational rules;
  2877 
  2878 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2879 rule (as well as the assumption rule);
  2880 
  2881 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2882 lemmas, using the graph browser tool;
  2883 
  2884 * Pure: predict failure of "show" in interactive mode;
  2885 
  2886 * Pure: 'thms_containing' now takes actual terms as arguments;
  2887 
  2888 * HOL: improved method 'induct' --- now handles non-atomic goals
  2889 (potential INCOMPATIBILITY); tuned error handling;
  2890 
  2891 * HOL: cases and induct rules now provide explicit hints about the
  2892 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2893 any remaining facts are inserted into the goal verbatim;
  2894 
  2895 * HOL: local contexts (aka cases) may now contain term bindings as
  2896 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2897 the result to be shown in each case;
  2898 
  2899 * HOL: added 'recdef_tc' command;
  2900 
  2901 * isatool convert assists in eliminating legacy ML scripts;
  2902 
  2903 
  2904 *** HOL ***
  2905 
  2906 * HOL/Library: a collection of generic theories to be used together
  2907 with main HOL; the theory loader path already includes this directory
  2908 by default; the following existing theories have been moved here:
  2909 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2910 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2911 
  2912 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2913 modelling and verification task performed in Isabelle/HOL +
  2914 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2915 
  2916 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2917 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2918 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2919 'domain', this makes the theory consistent with mathematical
  2920 literature;
  2921 
  2922 * HOL basics: added overloaded operations "inverse" and "divide"
  2923 (infix "/"), syntax for generic "abs" operation, generic summation
  2924 operator \<Sum>;
  2925 
  2926 * HOL/typedef: simplified package, provide more useful rules (see also
  2927 HOL/subset.thy);
  2928 
  2929 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2930 now expressed as a proper nested rule (old-style tactic scripts may
  2931 require atomize_strip_tac to cope with non-atomic premises);
  2932 
  2933 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2934 to "split_conv" (old name still available for compatibility);
  2935 
  2936 * HOL: improved concrete syntax for strings (e.g. allows translation
  2937 rules with string literals);
  2938 
  2939 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2940  and Fleuriot's mechanization of analysis, including the transcendental
  2941  functions for the reals;
  2942 
  2943 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2944 
  2945 
  2946 *** CTT ***
  2947 
  2948 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2949 "lam" is displayed as TWO lambda-symbols
  2950 
  2951 * CTT: theory Main now available, containing everything (that is, Bool
  2952 and Arith);
  2953 
  2954 
  2955 *** General ***
  2956 
  2957 * Pure: the Simplifier has been implemented properly as a derived rule
  2958 outside of the actual kernel (at last!); the overall performance
  2959 penalty in practical applications is about 50%, while reliability of
  2960 the Isabelle inference kernel has been greatly improved;
  2961 
  2962 * print modes "brackets" and "no_brackets" control output of nested =>
  2963 (types) and ==> (props); the default behaviour is "brackets";
  2964 
  2965 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2966 as assumptions as well;
  2967 
  2968 * system: support Poly/ML 4.0;
  2969 
  2970 * system: isatool install handles KDE version 1 or 2;
  2971 
  2972 
  2973 
  2974 New in Isabelle99-1 (October 2000)
  2975 ----------------------------------
  2976 
  2977 *** Overview of INCOMPATIBILITIES ***
  2978 
  2979 * HOL: simplification of natural numbers is much changed; to partly
  2980 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2981 issue the following ML commands:
  2982 
  2983   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2984   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2985 
  2986 * HOL: simplification no longer dives into case-expressions; this is
  2987 controlled by "t.weak_case_cong" for each datatype t;
  2988 
  2989 * HOL: nat_less_induct renamed to less_induct;
  2990 
  2991 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2992 fixsome to patch .thy and .ML sources automatically;
  2993 
  2994   select_equality  -> some_equality
  2995   select_eq_Ex     -> some_eq_ex
  2996   selectI2EX       -> someI2_ex
  2997   selectI2         -> someI2
  2998   selectI          -> someI
  2999   select1_equality -> some1_equality
  3000   Eps_sym_eq       -> some_sym_eq_trivial
  3001   Eps_eq           -> some_eq_trivial
  3002 
  3003 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3004 
  3005 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3006 instead);
  3007 
  3008 * HOL: the recursion equations generated by 'recdef' are now called
  3009 f.simps instead of f.rules;
  3010 
  3011 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3012 
  3013 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3014 sometimes be needed;
  3015 
  3016 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3017 
  3018 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3019 
  3020 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3021 product is now "<*>" instead of "Times"; the lexicographic product is
  3022 now "<*lex*>" instead of "**";
  3023 
  3024 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3025 of main HOL, but was unused); better use HOL's datatype package;
  3026 
  3027 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3028 the old syntax may be recovered as follows:
  3029 
  3030   syntax (symbols)
  3031     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3032       (infixl "\\<oplus>" 100)
  3033 
  3034 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3035 
  3036 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3037 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3038 internally;
  3039 
  3040 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3041 changed from A/r to A//r;
  3042 
  3043 * ZF: new treatment of arithmetic (nat & int) may break some old
  3044 proofs;
  3045 
  3046 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3047 rulify -> rule_format, elimify -> elim_format, ...);
  3048 
  3049 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3050 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3051 should have to change intro!! to intro? only); replaced "delrule" by
  3052 "rule del";
  3053 
  3054 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3055 
  3056 * Provers: strengthened force_tac by using new first_best_tac;
  3057 
  3058 * LaTeX document preparation: several changes of isabelle.sty (see
  3059 lib/texinputs);
  3060 
  3061 
  3062 *** Document preparation ***
  3063 
  3064 * formal comments (text blocks etc.) in new-style theories may now
  3065 contain antiquotations of thm/prop/term/typ/text to be presented
  3066 according to latex print mode; concrete syntax is like this:
  3067 @{term[show_types] "f(x) = a + x"};
  3068 
  3069 * isatool mkdir provides easy setup of Isabelle session directories,
  3070 including proper document sources;
  3071 
  3072 * generated LaTeX sources are now deleted after successful run
  3073 (isatool document -c); may retain a copy somewhere else via -D option
  3074 of isatool usedir;
  3075 
  3076 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3077 style files, achieving self-contained LaTeX sources and simplifying
  3078 LaTeX debugging;
  3079 
  3080 * old-style theories now produce (crude) LaTeX output as well;
  3081 
  3082 * browser info session directories are now self-contained (may be put
  3083 on WWW server seperately); improved graphs of nested sessions; removed
  3084 graph for 'all sessions';
  3085 
  3086 * several improvements in isabelle style files; \isabellestyle{it}
  3087 produces fake math mode output; \isamarkupheader is now \section by
  3088 default; see lib/texinputs/isabelle.sty etc.;
  3089 
  3090 
  3091 *** Isar ***
  3092 
  3093 * Isar/Pure: local results and corresponding term bindings are now
  3094 subject to Hindley-Milner polymorphism (similar to ML); this
  3095 accommodates incremental type-inference very nicely;
  3096 
  3097 * Isar/Pure: new derived language element 'obtain' supports
  3098 generalized existence reasoning;
  3099 
  3100 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3101 support accumulation of results, without applying any rules yet;
  3102 useful to collect intermediate results without explicit name
  3103 references, and for use with transitivity rules with more than 2
  3104 premises;
  3105 
  3106 * Isar/Pure: scalable support for case-analysis type proofs: new
  3107 'case' language element refers to local contexts symbolically, as
  3108 produced by certain proof methods; internally, case names are attached
  3109 to theorems as "tags";
  3110 
  3111 * Isar/Pure: theory command 'hide' removes declarations from
  3112 class/type/const name spaces;
  3113 
  3114 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3115 indicate potential overloading;
  3116 
  3117 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3118 
  3119 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3120 "{a,b,c}" instead of {a,b,c};
  3121 
  3122 * Isar/Pure now provides its own version of intro/elim/dest
  3123 attributes; useful for building new logics, but beware of confusion
  3124 with the version in Provers/classical;
  3125 
  3126 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3127 case name 'antecedent';
  3128 
  3129 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3130 to the current context is now done automatically);
  3131 
  3132 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3133 for definining proof methods in ML;
  3134 
  3135 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3136 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3137 most cases, one should have to change intro!! to intro? only);
  3138 replaced "delrule" by "rule del";
  3139 
  3140 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3141 'symmetric' attribute (the latter supercedes [RS sym]);
  3142 
  3143 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3144 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3145 well (including splits);
  3146 
  3147 * Isar/Provers: Simplifier and Classical methods now support all kind
  3148 of modifiers used in the past, including 'cong', 'iff', etc.
  3149 
  3150 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3151 of Simplifier and Classical reasoner);
  3152 
  3153 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3154 now support named cases; major packages (inductive, datatype, primrec,
  3155 recdef) support case names and properly name parameters;
  3156 
  3157 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3158 monotonicity conditions are extracted to be proven at end of
  3159 calculations;
  3160 
  3161 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3162 method anyway;
  3163 
  3164 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3165 split_if split_if_asm; datatype package provides theorems foo.splits =
  3166 foo.split foo.split_asm for each datatype;
  3167 
  3168 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3169 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3170 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3171 use "(cases (simplified))" method in proper proof texts);
  3172 
  3173 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3174 
  3175 * Isar: names of theorems etc. may be natural numbers as well;
  3176 
  3177 * Isar: 'pr' command: optional arguments for goals_limit and
  3178 ProofContext.prems_limit; no longer prints theory contexts, but only
  3179 proof states;
  3180 
  3181 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3182 additional print modes to be specified; e.g. "pr(latex)" will print
  3183 proof state according to the Isabelle LaTeX style;
  3184 
  3185 * Isar: improved support for emulating tactic scripts, including proof
  3186 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3187 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3188 (for HOL datatypes);
  3189 
  3190 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3191 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3192 'proof method scripts' have to be in depth-first order;
  3193 
  3194 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3195 
  3196 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3197 should instead use individual commands for printing items
  3198 (print_commands, print_methods etc.);
  3199 
  3200 * Isar: added 'nothing' --- the empty list of theorems;
  3201 
  3202 
  3203 *** HOL ***
  3204 
  3205 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3206 corresponding virtual machine and a specification of its bytecode
  3207 verifier and a lightweight bytecode verifier, including proofs of
  3208 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3209 Cornelia Pusch (see also the homepage of project Bali at
  3210 http://isabelle.in.tum.de/Bali/);
  3211 
  3212 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3213 Clemens Ballarin;
  3214 
  3215 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3216 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3217 Rasmussen;
  3218 
  3219 * HOL/Lattice: fundamental concepts of lattice theory and order
  3220 structures, including duals, properties of bounds versus algebraic
  3221 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3222 Theorem for complete lattices etc.; may also serve as a demonstration
  3223 for abstract algebraic reasoning using axiomatic type classes, and
  3224 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3225 
  3226 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3227 von Oheimb;
  3228 
  3229 * HOL/IMPP: extension of IMP with local variables and mutually
  3230 recursive procedures, by David von Oheimb;
  3231 
  3232 * HOL/Lambda: converted into new-style theory and document;
  3233 
  3234 * HOL/ex/Multiquote: example of multiple nested quotations and
  3235 anti-quotations -- basically a generalized version of de-Bruijn
  3236 representation; very useful in avoiding lifting of operations;
  3237 
  3238 * HOL/record: added general record equality rule to simpset; fixed
  3239 select-update simplification procedure to handle extended records as
  3240 well; admit "r" as field name;
  3241 
  3242 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3243 other numeric types and also as the identity of groups, rings, etc.;
  3244 
  3245 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3246 Types nat and int belong to this axclass;
  3247 
  3248 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3249    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3250    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3251   two terms #m*u and #n*u are replaced by #(m+n)*u
  3252     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3253   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3254     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3255 
  3256 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3257 powerful prover for predicate logic but knows nothing of clasets; see
  3258 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3259 
  3260 * HOL: new version of "case_tac" subsumes both boolean case split and
  3261 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3262 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3263 
  3264 * HOL: simplification no longer dives into case-expressions: only the
  3265 selector expression is simplified, but not the remaining arms; to
  3266 enable full simplification of case-expressions for datatype t, you may
  3267 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3268 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3269 
  3270 * HOL/recdef: the recursion equations generated by 'recdef' for
  3271 function 'f' are now called f.simps instead of f.rules; if all
  3272 termination conditions are proved automatically, these simplification
  3273 rules are added to the simpset, as in primrec; rules may be named
  3274 individually as well, resulting in a separate list of theorems for
  3275 each equation;
  3276 
  3277 * HOL/While is a new theory that provides a while-combinator. It
  3278 permits the definition of tail-recursive functions without the
  3279 provision of a termination measure. The latter is necessary once the
  3280 invariant proof rule for while is applied.
  3281 
  3282 * HOL: new (overloaded) notation for the set of elements below/above
  3283 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3284 
  3285 * HOL: theorems impI, allI, ballI bound as "strip";
  3286 
  3287 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3288 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3289 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3290 
  3291 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3292 
  3293 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3294 main HOL, but was unused);
  3295 
  3296 * HOL: fewer consts declared as global (e.g. have to refer to
  3297 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3298 
  3299 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3300 in case of overlap with user translations (e.g. judgements over
  3301 tuples); (note that the underlying logical represenation is still
  3302 bogus);
  3303 
  3304 
  3305 *** ZF ***
  3306 
  3307 * ZF: simplification automatically cancels common terms in arithmetic
  3308 expressions over nat and int;
  3309 
  3310 * ZF: new treatment of nat to minimize type-checking: all operators
  3311 coerce their operands to a natural number using the function natify,
  3312 making the algebraic laws unconditional;
  3313 
  3314 * ZF: as above, for int: operators coerce their operands to an integer
  3315 using the function intify;
  3316 
  3317 * ZF: the integer library now contains many of the usual laws for the
  3318 orderings, including $<=, and monotonicity laws for $+ and $*;
  3319 
  3320 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3321 simplification;
  3322 
  3323 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3324 to the simplifier and classical reasoner simultaneously;
  3325 
  3326 
  3327 *** General ***
  3328 
  3329 * Provers: blast_tac now handles actual object-logic rules as
  3330 assumptions; note that auto_tac uses blast_tac internally as well;
  3331 
  3332 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3333 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3334 
  3335 * Provers: delrules now handles destruct rules as well (no longer need
  3336 explicit make_elim);
  3337 
  3338 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3339   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3340 use instead the strong form,
  3341   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3342 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3343 from destruct-rules;
  3344 
  3345 * Provers: Simplifier.easy_setup provides a fast path to basic
  3346 Simplifier setup for new object-logics;
  3347 
  3348 * Pure: AST translation rules no longer require constant head on LHS;
  3349 
  3350 * Pure: improved name spaces: ambiguous output is qualified; support
  3351 for hiding of names;
  3352 
  3353 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3354 XSYMBOL_HOME; no longer need to do manual configuration in most
  3355 situations;
  3356 
  3357 * system: compression of ML heaps images may now be controlled via -c
  3358 option of isabelle and isatool usedir (currently only observed by
  3359 Poly/ML);
  3360 
  3361 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3362 useful for remote X11);
  3363 
  3364 * system: provide TAGS file for Isabelle sources;
  3365 
  3366 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3367 order;
  3368 
  3369 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3370 timing flag supersedes proof_timing and Toplevel.trace;
  3371 
  3372 * ML: new combinators |>> and |>>> for incremental transformations
  3373 with secondary results (e.g. certain theory extensions):
  3374 
  3375 * ML: PureThy.add_defs gets additional argument to indicate potential
  3376 overloading (usually false);
  3377 
  3378 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3379 results;
  3380 
  3381 
  3382 
  3383 New in Isabelle99 (October 1999)
  3384 --------------------------------
  3385 
  3386 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3387 
  3388 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3389 are no longer simplified.  (This allows the simplifier to unfold recursive
  3390 functional programs.)  To restore the old behaviour, declare
  3391 
  3392     Delcongs [if_weak_cong];
  3393 
  3394 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3395 complement;
  3396 
  3397 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3398 
  3399 * HOL/datatype: mutual_induct_tac no longer exists --
  3400   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3401 
  3402 * HOL/typedef: fixed type inference for representing set; type
  3403 arguments now have to occur explicitly on the rhs as type constraints;
  3404 
  3405 * ZF: The con_defs part of an inductive definition may no longer refer
  3406 to constants declared in the same theory;
  3407 
  3408 * HOL, ZF: the function mk_cases, generated by the inductive
  3409 definition package, has lost an argument.  To simplify its result, it
  3410 uses the default simpset instead of a supplied list of theorems.
  3411 
  3412 * HOL/List: the constructors of type list are now Nil and Cons;
  3413 
  3414 * Simplifier: the type of the infix ML functions
  3415         setSSolver addSSolver setSolver addSolver
  3416 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3417 for packaging solvers. A solver is created via
  3418         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3419 where the string argument is only a comment.
  3420 
  3421 
  3422 *** Proof tools ***
  3423 
  3424 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3425 decision procedure for linear arithmetic. Currently it is used for
  3426 types `nat', `int', and `real' in HOL (see below); it can, should and
  3427 will be instantiated for other types and logics as well.
  3428 
  3429 * The simplifier now accepts rewrite rules with flexible heads, eg
  3430      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3431   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3432   matching.
  3433 
  3434 
  3435 *** General ***
  3436 
  3437 * New Isabelle/Isar subsystem provides an alternative to traditional
  3438 tactical theorem proving; together with the ProofGeneral/isar user
  3439 interface it offers an interactive environment for developing human
  3440 readable proof documents (Isar == Intelligible semi-automated
  3441 reasoning); for further information see isatool doc isar-ref,
  3442 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3443 
  3444 * improved and simplified presentation of theories: better HTML markup
  3445 (including colors), graph views in several sizes; isatool usedir now
  3446 provides a proper interface for user theories (via -P option); actual
  3447 document preparation based on (PDF)LaTeX is available as well (for
  3448 new-style theories only); see isatool doc system for more information;
  3449 
  3450 * native support for Proof General, both for classic Isabelle and
  3451 Isabelle/Isar;
  3452 
  3453 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3454 using the graph browser tool;
  3455 
  3456 * Isabelle manuals now also available as PDF;
  3457 
  3458 * theory loader rewritten from scratch (may not be fully
  3459 bug-compatible); old loadpath variable has been replaced by show_path,
  3460 add_path, del_path, reset_path functions; new operations such as
  3461 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3462 isatool doc ref);
  3463 
  3464 * improved isatool install: option -k creates KDE application icon,
  3465 option -p DIR installs standalone binaries;
  3466 
  3467 * added ML_PLATFORM setting (useful for cross-platform installations);
  3468 more robust handling of platform specific ML images for SML/NJ;
  3469 
  3470 * the settings environment is now statically scoped, i.e. it is never
  3471 created again in sub-processes invoked from isabelle, isatool, or
  3472 Isabelle;
  3473 
  3474 * path element specification '~~' refers to '$ISABELLE_HOME';
  3475 
  3476 * in locales, the "assumes" and "defines" parts may be omitted if
  3477 empty;
  3478 
  3479 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3480 long arrows);
  3481 
  3482 * new print_mode "HTML";
  3483 
  3484 * new flag show_tags controls display of tags of theorems (which are
  3485 basically just comments that may be attached by some tools);
  3486 
  3487 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3488 mode and goal output format:
  3489 
  3490 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3491 244c244
  3492 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3493 ---
  3494 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3495 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3496 181c181
  3497 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3498 ---
  3499 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3500 
  3501 * function bind_thms stores lists of theorems (cf. bind_thm);
  3502 
  3503 * new shorthand tactics ftac, eatac, datac, fatac;
  3504 
  3505 * qed (and friends) now accept "" as result name; in that case the
  3506 theorem is not stored, but proper checks and presentation of the
  3507 result still apply;
  3508 
  3509 * theorem database now also indexes constants "Trueprop", "all",
  3510 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3511 
  3512 
  3513 *** HOL ***
  3514 
  3515 ** HOL arithmetic **
  3516 
  3517 * There are now decision procedures for linear arithmetic over nat and
  3518 int:
  3519 
  3520 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3521 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3522 are treated as atomic; subformulae not involving type `nat' or `int'
  3523 are ignored; quantified subformulae are ignored unless they are
  3524 positive universal or negative existential. The tactic has to be
  3525 invoked by hand and can be a little bit slow. In particular, the
  3526 running time is exponential in the number of occurrences of `min' and
  3527 `max', and `-' on `nat'.
  3528 
  3529 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3530 (negated) (in)equalities among the premises and the conclusion into
  3531 account (i.e. no compound formulae) and does not know about `min' and
  3532 `max', and `-' on `nat'. It is fast and is used automatically by the
  3533 simplifier.
  3534 
  3535 NB: At the moment, these decision procedures do not cope with mixed
  3536 nat/int formulae where the two parts interact, such as `m < n ==>
  3537 int(m) < int(n)'.
  3538 
  3539 * HOL/Numeral provides a generic theory of numerals (encoded
  3540 efficiently as bit strings); setup for types nat/int/real is in place;
  3541 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3542 int, existing theories and proof scripts may require a few additional
  3543 type constraints;
  3544 
  3545 * integer division and remainder can now be performed on constant
  3546 arguments;
  3547 
  3548 * many properties of integer multiplication, division and remainder
  3549 are now available;
  3550 
  3551 * An interface to the Stanford Validity Checker (SVC) is available through the
  3552 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3553 are proved automatically.  SVC must be installed separately, and its results
  3554 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3555 invocation of the underlying oracle).  For SVC see
  3556   http://verify.stanford.edu/SVC
  3557 
  3558 * IsaMakefile: the HOL-Real target now builds an actual image;
  3559 
  3560 
  3561 ** HOL misc **
  3562 
  3563 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3564 (in Isabelle/Isar) -- by Gertrud Bauer;
  3565 
  3566 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3567 analysis for assembly languages with subtypes;
  3568 
  3569 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3570 -- avoids syntactic ambiguities and treats state, transition, and
  3571 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3572 changed syntax and (many) tactics;
  3573 
  3574 * HOL/inductive: Now also handles more general introduction rules such
  3575   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3576   theorems are now maintained within the theory (maintained via the
  3577   "mono" attribute);
  3578 
  3579 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3580   (using function types) such as
  3581 
  3582   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3583 
  3584 * HOL/record: record_simproc (part of the default simpset) takes care
  3585 of selectors applied to updated records; record_split_tac is no longer
  3586 part of the default claset; update_defs may now be removed from the
  3587 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3588 
  3589   claset_ref () := claset() addSWrapper record_split_wrapper;
  3590   Delsimprocs [record_simproc]
  3591 
  3592 * HOL/typedef: fixed type inference for representing set; type
  3593 arguments now have to occur explicitly on the rhs as type constraints;
  3594 
  3595 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3596 names rather than an ML expression;
  3597 
  3598 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3599 supplied later.  Program schemes can be defined, such as
  3600     "While B C s = (if B s then While B C (C s) else s)"
  3601 where the well-founded relation can be chosen after B and C have been given.
  3602 
  3603 * HOL/List: the constructors of type list are now Nil and Cons;
  3604 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3605 course, ML tools referring to List.list.op # etc. have to be adapted;
  3606 
  3607 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3608 disabled by default; run isabelle with option -m HOL to get back to
  3609 the original Gordon/HOL-style output;
  3610 
  3611 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3612 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3613 
  3614 * HOL basic syntax simplified (more orthogonal): all variants of
  3615 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3616 Eps operator is provided as well: "SOME x. P[x]";
  3617 
  3618 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3619 
  3620 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3621 thus available for user theories;
  3622 
  3623 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3624 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3625 time;
  3626 
  3627 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3628 several times and then mp;
  3629 
  3630 
  3631 *** LK ***
  3632 
  3633 * the notation <<...>> is now available as a notation for sequences of
  3634 formulas;
  3635 
  3636 * the simplifier is now installed
  3637 
  3638 * the axiom system has been generalized (thanks to Soren Heilmann)
  3639 
  3640 * the classical reasoner now has a default rule database
  3641 
  3642 
  3643 *** ZF ***
  3644 
  3645 * new primrec section allows primitive recursive functions to be given
  3646 directly (as in HOL) over datatypes and the natural numbers;
  3647 
  3648 * new tactics induct_tac and exhaust_tac for induction (or case
  3649 analysis) over datatypes and the natural numbers;
  3650 
  3651 * the datatype declaration of type T now defines the recursor T_rec;
  3652 
  3653 * simplification automatically does freeness reasoning for datatype
  3654 constructors;
  3655 
  3656 * automatic type-inference, with AddTCs command to insert new
  3657 type-checking rules;
  3658 
  3659 * datatype introduction rules are now added as Safe Introduction rules
  3660 to the claset;
  3661 
  3662 * the syntax "if P then x else y" is now available in addition to
  3663 if(P,x,y);
  3664 
  3665 
  3666 *** Internal programming interfaces ***
  3667 
  3668 * tuned simplifier trace output; new flag debug_simp;
  3669 
  3670 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3671 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3672 
  3673 * AxClass.axclass_tac lost the theory argument;
  3674 
  3675 * tuned current_goals_markers semantics: begin / end goal avoids
  3676 printing empty lines;
  3677 
  3678 * removed prs and prs_fn hook, which was broken because it did not
  3679 include \n in its semantics, forcing writeln to add one
  3680 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3681 string -> unit if you really want to output text without newline;
  3682 
  3683 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3684 plain output, interface builders may have to enable 'isabelle_font'
  3685 mode to get Isabelle font glyphs as before;
  3686 
  3687 * refined token_translation interface; INCOMPATIBILITY: output length
  3688 now of type real instead of int;
  3689 
  3690 * theory loader actions may be traced via new ThyInfo.add_hook
  3691 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3692 your own database of information attached to *whole* theories -- as
  3693 opposed to intra-theory data slots offered via TheoryDataFun;
  3694 
  3695 * proper handling of dangling sort hypotheses (at last!);
  3696 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3697 extra sort hypotheses that can be witnessed from the type signature;
  3698 the force_strip_shyps flag is gone, any remaining shyps are simply
  3699 left in the theorem (with a warning issued by strip_shyps_warning);
  3700 
  3701 
  3702 
  3703 New in Isabelle98-1 (October 1998)
  3704 ----------------------------------
  3705 
  3706 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3707 
  3708 * several changes of automated proof tools;
  3709 
  3710 * HOL: major changes to the inductive and datatype packages, including
  3711 some minor incompatibilities of theory syntax;
  3712 
  3713 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3714 called `inj_on';
  3715 
  3716 * HOL: removed duplicate thms in Arith:
  3717   less_imp_add_less  should be replaced by  trans_less_add1
  3718   le_imp_add_le      should be replaced by  trans_le_add1
  3719 
  3720 * HOL: unary minus is now overloaded (new type constraints may be
  3721 required);
  3722 
  3723 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3724 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3725 now taken as an integer constant.
  3726 
  3727 * Pure: ML function 'theory_of' renamed to 'theory';
  3728 
  3729 
  3730 *** Proof tools ***
  3731 
  3732 * Simplifier:
  3733   1. Asm_full_simp_tac is now more aggressive.
  3734      1. It will sometimes reorient premises if that increases their power to
  3735         simplify.
  3736      2. It does no longer proceed strictly from left to right but may also
  3737         rotate premises to achieve further simplification.
  3738      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3739      old Asm_full_simp_tac in that it does not rotate premises.
  3740   2. The simplifier now knows a little bit about nat-arithmetic.
  3741 
  3742 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3743 allows for selected deletion of wrappers, by introduction of names for
  3744 wrapper functionals.  This implies that addbefore, addSbefore,
  3745 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3746 and that adding two tactics with the same name overwrites the first
  3747 one (emitting a warning).
  3748   type wrapper = (int -> tactic) -> (int -> tactic)
  3749   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3750   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3751   delWrapper, delSWrapper: claset *  string            -> claset
  3752   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3753 
  3754 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3755 semantics; addbefore now affects only the unsafe part of step_tac
  3756 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3757 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3758 by Force_tac;
  3759 
  3760 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3761 compWrapper; added safe wrapper (and access functions for it);
  3762 
  3763 * HOL/split_all_tac is now much faster and fails if there is nothing
  3764 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3765 and the names of the automatically generated variables have changed.
  3766 split_all_tac has moved within claset() from unsafe wrappers to safe
  3767 wrappers, which means that !!-bound variables are split much more
  3768 aggressively, and safe_tac and clarify_tac now split such variables.
  3769 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3770 Note: the same holds for record_split_tac, which does the job of
  3771 split_all_tac for record fields.
  3772 
  3773 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3774 permanently to the default simpset using Addsplits just like
  3775 Addsimps. They can be removed via Delsplits just like
  3776 Delsimps. Lower-case versions are also available.
  3777 
  3778 * HOL/Simplifier: The rule split_if is now part of the default
  3779 simpset. This means that the simplifier will eliminate all occurrences
  3780 of if-then-else in the conclusion of a goal. To prevent this, you can
  3781 either remove split_if completely from the default simpset by
  3782 `Delsplits [split_if]' or remove it in a specific call of the
  3783 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3784 other case splitting rules to/from the default simpset: every datatype
  3785 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3786 t is the name of the datatype).
  3787 
  3788 * Classical reasoner / Simplifier combination: new force_tac (and
  3789 derivatives Force_tac, force) combines rewriting and classical
  3790 reasoning (and whatever other tools) similarly to auto_tac, but is
  3791 aimed to solve the given subgoal completely.
  3792 
  3793 
  3794 *** General ***
  3795 
  3796 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3797 and `goalw': the theory is no longer needed as an explicit argument -
  3798 the current theory context is used; assumptions are no longer returned
  3799 at the ML-level unless one of them starts with ==> or !!; it is
  3800 recommended to convert to these new commands using isatool fixgoal
  3801 (backup your sources first!);
  3802 
  3803 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3804 the current theory context, and 'theory' to lookup stored theories;
  3805 
  3806 * new theory section 'locale' for declaring constants, assumptions and
  3807 definitions that have local scope;
  3808 
  3809 * new theory section 'nonterminals' for purely syntactic types;
  3810 
  3811 * new theory section 'setup' for generic ML setup functions
  3812 (e.g. package initialization);
  3813 
  3814 * the distribution now includes Isabelle icons: see
  3815 lib/logo/isabelle-{small,tiny}.xpm;
  3816 
  3817 * isatool install - install binaries with absolute references to
  3818 ISABELLE_HOME/bin;
  3819 
  3820 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3821 
  3822 * print mode 'emacs' reserved for Isamode;
  3823 
  3824 * support multiple print (ast) translations per constant name;
  3825 
  3826 * theorems involving oracles are now printed with a suffixed [!];
  3827 
  3828 
  3829 *** HOL ***
  3830 
  3831 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3832 
  3833 * HOL/inductive package reorganized and improved: now supports mutual
  3834 definitions such as
  3835 
  3836   inductive EVEN ODD
  3837     intrs
  3838       null "0 : EVEN"
  3839       oddI "n : EVEN ==> Suc n : ODD"
  3840       evenI "n : ODD ==> Suc n : EVEN"
  3841 
  3842 new theorem list "elims" contains an elimination rule for each of the
  3843 recursive sets; inductive definitions now handle disjunctive premises
  3844 correctly (also ZF);
  3845 
  3846 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3847 "mutual_induct" no longer exists - the induction rule is always
  3848 contained in "induct";
  3849 
  3850 
  3851 * HOL/datatype package re-implemented and greatly improved: now
  3852 supports mutually recursive datatypes such as
  3853 
  3854   datatype
  3855     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3856             | SUM ('a aexp) ('a aexp)
  3857             | DIFF ('a aexp) ('a aexp)
  3858             | NUM 'a
  3859   and
  3860     'a bexp = LESS ('a aexp) ('a aexp)
  3861             | AND ('a bexp) ('a bexp)
  3862             | OR ('a bexp) ('a bexp)
  3863 
  3864 as well as indirectly recursive datatypes such as
  3865 
  3866   datatype
  3867     ('a, 'b) term = Var 'a
  3868                   | App 'b ((('a, 'b) term) list)
  3869 
  3870 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3871 induction on mutually / indirectly recursive datatypes.
  3872 
  3873 Primrec equations are now stored in theory and can be accessed via
  3874 <function_name>.simps.
  3875 
  3876 INCOMPATIBILITIES:
  3877 
  3878   - Theories using datatypes must now have theory Datatype as an
  3879     ancestor.
  3880   - The specific <typename>.induct_tac no longer exists - use the
  3881     generic induct_tac instead.
  3882   - natE has been renamed to nat.exhaust - use exhaust_tac
  3883     instead of res_inst_tac ... natE. Note that the variable
  3884     names in nat.exhaust differ from the names in natE, this
  3885     may cause some "fragile" proofs to fail.
  3886   - The theorems split_<typename>_case and split_<typename>_case_asm
  3887     have been renamed to <typename>.split and <typename>.split_asm.
  3888   - Since default sorts of type variables are now handled correctly,
  3889     some datatype definitions may have to be annotated with explicit
  3890     sort constraints.
  3891   - Primrec definitions no longer require function name and type
  3892     of recursive argument.
  3893 
  3894 Consider using isatool fixdatatype to adapt your theories and proof
  3895 scripts to the new package (backup your sources first!).
  3896 
  3897 
  3898 * HOL/record package: considerably improved implementation; now
  3899 includes concrete syntax for record types, terms, updates; theorems
  3900 for surjective pairing and splitting !!-bound record variables; proof
  3901 support is as follows:
  3902 
  3903   1) standard conversions (selectors or updates applied to record
  3904 constructor terms) are part of the standard simpset;
  3905 
  3906   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3907 made part of standard simpset and claset via addIffs;
  3908 
  3909   3) a tactic for record field splitting (record_split_tac) is part of
  3910 the standard claset (addSWrapper);
  3911 
  3912 To get a better idea about these rules you may retrieve them via
  3913 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3914 the name of your record type.
  3915 
  3916 The split tactic 3) conceptually simplifies by the following rule:
  3917 
  3918   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3919 
  3920 Thus any record variable that is bound by meta-all will automatically
  3921 blow up into some record constructor term, consequently the
  3922 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3923 solve record problems automatically.
  3924 
  3925 
  3926 * reorganized the main HOL image: HOL/Integ and String loaded by
  3927 default; theory Main includes everything;
  3928 
  3929 * automatic simplification of integer sums and comparisons, using cancellation;
  3930 
  3931 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3932 
  3933 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3934 
  3935 * many new identities for unions, intersections, set difference, etc.;
  3936 
  3937 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3938 called split_if, split_split, split_sum_case and split_nat_case (to go
  3939 with add/delsplits);
  3940 
  3941 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3942 (?x::unit) = (); this is made part of the default simpset, which COULD
  3943 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3944 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3945 unit_abs_eta_conv is added in order to counter the effect of
  3946 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3947 %u.f();
  3948 
  3949 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3950 makes more sense);
  3951 
  3952 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3953   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3954   disjointness reasoning but breaking a few old proofs.
  3955 
  3956 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3957 to 'converse' from 'inverse' (for compatibility with ZF and some
  3958 literature);
  3959 
  3960 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3961 the well-founded relation;
  3962 
  3963 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3964     Compl A.  The "Compl" syntax remains available as input syntax for this
  3965     release ONLY.
  3966 
  3967 * HOL/Update: new theory of function updates:
  3968     f(a:=b) == %x. if x=a then b else f x
  3969 may also be iterated as in f(a:=b,c:=d,...);
  3970 
  3971 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3972 
  3973 * HOL/List:
  3974   - new function list_update written xs[i:=v] that updates the i-th
  3975     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3976   - new function `upt' written [i..j(] which generates the list
  3977     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3978     bound write [i..j], which is a shorthand for [i..j+1(].
  3979   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3980 
  3981 * HOL/Arith:
  3982   - removed 'pred' (predecessor) function;
  3983   - generalized some theorems about n-1;
  3984   - many new laws about "div" and "mod";
  3985   - new laws about greatest common divisors (see theory ex/Primes);
  3986 
  3987 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3988 instead of "inverse";
  3989 
  3990 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3991   of the multiset ordering;
  3992 
  3993 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3994   (not included by default);
  3995 
  3996 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3997 
  3998 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3999   programs, i.e. different program variables may have different types.
  4000 
  4001 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4002   [previously, this check worked only if the rewrite rule was unconditional]
  4003   Now rew can involve either definitions or equalities (either == or =).
  4004 
  4005 
  4006 *** ZF ***
  4007 
  4008 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4009   only the theorems proved on ZF.ML;
  4010 
  4011 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4012   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4013   disjointness reasoning but breaking a few old proofs.
  4014 
  4015 * ZF/Update: new theory of function updates
  4016     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4017   may also be iterated as in f(a:=b,c:=d,...);
  4018 
  4019 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4020 
  4021 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4022   [previously, this check worked only if the rewrite rule was unconditional]
  4023   Now rew can involve either definitions or equalities (either == or =).
  4024 
  4025 * case_tac provided for compatibility with HOL
  4026     (like the old excluded_middle_tac, but with subgoals swapped)
  4027 
  4028 
  4029 *** Internal programming interfaces ***
  4030 
  4031 * Pure: several new basic modules made available for general use, see
  4032 also src/Pure/README;
  4033 
  4034 * improved the theory data mechanism to support encapsulation (data
  4035 kind name replaced by private Object.kind, acting as authorization
  4036 key); new type-safe user interface via functor TheoryDataFun; generic
  4037 print_data function becomes basically useless;
  4038 
  4039 * removed global_names compatibility flag -- all theory declarations
  4040 are qualified by default;
  4041 
  4042 * module Pure/Syntax now offers quote / antiquote translation
  4043 functions (useful for Hoare logic etc. with implicit dependencies);
  4044 see HOL/ex/Antiquote for an example use;
  4045 
  4046 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4047 cterm -> thm;
  4048 
  4049 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4050 subgoal;
  4051 
  4052 * Display.print_goals function moved to Locale.print_goals;
  4053 
  4054 * standard print function for goals supports current_goals_markers
  4055 variable for marking begin of proof, end of proof, start of goal; the
  4056 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4057 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4058 for example;
  4059 
  4060 
  4061 
  4062 New in Isabelle98 (January 1998)
  4063 --------------------------------
  4064 
  4065 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4066 
  4067 * changed lexical syntax of terms / types: dots made part of long
  4068 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4069 
  4070 * simpset (and claset) reference variable replaced by functions
  4071 simpset / simpset_ref;
  4072 
  4073 * no longer supports theory aliases (via merge) and non-trivial
  4074 implicit merge of thms' signatures;
  4075 
  4076 * most internal names of constants changed due to qualified names;
  4077 
  4078 * changed Pure/Sequence interface (see Pure/seq.ML);
  4079 
  4080 
  4081 *** General Changes ***
  4082 
  4083 * hierachically structured name spaces (for consts, types, axms, thms
  4084 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4085 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4086 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4087 long_names for fully qualified output names; NOTE: ML programs
  4088 (special tactics, packages etc.) referring to internal names may have
  4089 to be adapted to cope with fully qualified names; in case of severe
  4090 backward campatibility problems try setting 'global_names' at compile
  4091 time to have enrything declared within a flat name space; one may also
  4092 fine tune name declarations in theories via the 'global' and 'local'
  4093 section;
  4094 
  4095 * reimplemented the implicit simpset and claset using the new anytype
  4096 data filed in signatures; references simpset:simpset ref etc. are
  4097 replaced by functions simpset:unit->simpset and
  4098 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4099 to patch your ML files accordingly;
  4100 
  4101 * HTML output now includes theory graph data for display with Java
  4102 applet or isatool browser; data generated automatically via isatool
  4103 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4104 
  4105 * defs may now be conditional; improved rewrite_goals_tac to handle
  4106 conditional equations;
  4107 
  4108 * defs now admits additional type arguments, using TYPE('a) syntax;
  4109 
  4110 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4111 creates a new theory node; implicit merge of thms' signatures is
  4112 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4113 transfer:theory->thm->thm in (rare) cases;
  4114 
  4115 * improved handling of draft signatures / theories; draft thms (and
  4116 ctyps, cterms) are automatically promoted to real ones;
  4117 
  4118 * slightly changed interfaces for oracles: admit many per theory, named
  4119 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4120 
  4121 * print_goals: optional output of const types (set show_consts and
  4122 show_types);
  4123 
  4124 * improved output of warnings (###) and errors (***);
  4125 
  4126 * subgoal_tac displays a warning if the new subgoal has type variables;
  4127 
  4128 * removed old README and Makefiles;
  4129 
  4130 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4131 
  4132 * removed obsolete init_pps and init_database;
  4133 
  4134 * deleted the obsolete tactical STATE, which was declared by
  4135     fun STATE tacfun st = tacfun st st;
  4136 
  4137 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4138 (which abbreviates $HOME);
  4139 
  4140 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4141 use isatool fixseq to adapt your ML programs (this works for fully
  4142 qualified references to the Sequence structure only!);
  4143 
  4144 * use_thy no longer requires writable current directory; it always
  4145 reloads .ML *and* .thy file, if either one is out of date;
  4146 
  4147 
  4148 *** Classical Reasoner ***
  4149 
  4150 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4151 tactics that use classical reasoning to simplify a subgoal without
  4152 splitting it into several subgoals;
  4153 
  4154 * Safe_tac: like safe_tac but uses the default claset;
  4155 
  4156 
  4157 *** Simplifier ***
  4158 
  4159 * added simplification meta rules:
  4160     (asm_)(full_)simplify: simpset -> thm -> thm;
  4161 
  4162 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4163 logics (again);
  4164 
  4165 * added prems argument to simplification procedures;
  4166 
  4167 * HOL, FOL, ZF: added infix function `addsplits':
  4168   instead of `<simpset> setloop (split_tac <thms>)'
  4169   you can simply write `<simpset> addsplits <thms>'
  4170 
  4171 
  4172 *** Syntax ***
  4173 
  4174 * TYPE('a) syntax for type reflection terms;
  4175 
  4176 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4177 
  4178 * pretty printer: changed order of mixfix annotation preference (again!);
  4179 
  4180 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4181 
  4182 
  4183 *** HOL ***
  4184 
  4185 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4186   with `addloop' of the simplifier to faciliate case splitting in premises.
  4187 
  4188 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4189 
  4190 * HOL/Auth: new protocol proofs including some for the Internet
  4191   protocol TLS;
  4192 
  4193 * HOL/Map: new theory of `maps' a la VDM;
  4194 
  4195 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4196 cancelling out common nat summands from =, <, <= (in)equalities, or
  4197 differences; simplification procedures nat_cancel_factor for
  4198 cancelling common factor from =, <, <= (in)equalities over natural
  4199 sums; nat_cancel contains both kinds of procedures, it is installed by
  4200 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4201 
  4202 * HOL/simplifier: terms of the form
  4203   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4204   are rewritten to
  4205   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4206   and those of the form
  4207   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4208   are rewritten to
  4209   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4210 
  4211 * HOL/datatype
  4212   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4213 
  4214   P(t_case f1 ... fn x) =
  4215      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4216         ...
  4217        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4218      )
  4219 
  4220   and a theorem `split_t_case_asm' of the form
  4221 
  4222   P(t_case f1 ... fn x) =
  4223     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4224         ...
  4225        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4226      )
  4227   which can be added to a simpset via `addsplits'. The existing theorems
  4228   expand_list_case and expand_option_case have been renamed to
  4229   split_list_case and split_option_case.
  4230 
  4231 * HOL/Arithmetic:
  4232   - `pred n' is automatically converted to `n-1'.
  4233     Users are strongly encouraged not to use `pred' any longer,
  4234     because it will disappear altogether at some point.
  4235   - Users are strongly encouraged to write "0 < n" rather than
  4236     "n ~= 0". Theorems and proof tools have been modified towards this
  4237     `standard'.
  4238 
  4239 * HOL/Lists:
  4240   the function "set_of_list" has been renamed "set" (and its theorems too);
  4241   the function "nth" now takes its arguments in the reverse order and
  4242   has acquired the infix notation "!" as in "xs!n".
  4243 
  4244 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4245 
  4246 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4247   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4248 
  4249 * HOL/record: extensible records with schematic structural subtyping
  4250 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4251 still lacks various theorems and concrete record syntax;
  4252 
  4253 
  4254 *** HOLCF ***
  4255 
  4256 * removed "axioms" and "generated by" sections;
  4257 
  4258 * replaced "ops" section by extended "consts" section, which is capable of
  4259   handling the continuous function space "->" directly;
  4260 
  4261 * domain package:
  4262   . proves theorems immediately and stores them in the theory,
  4263   . creates hierachical name space,
  4264   . now uses normal mixfix annotations (instead of cinfix...),
  4265   . minor changes to some names and values (for consistency),
  4266   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4267   . separator between mutual domain defs: changed "," to "and",
  4268   . improved handling of sort constraints;  now they have to
  4269     appear on the left-hand side of the equations only;
  4270 
  4271 * fixed LAM <x,y,zs>.b syntax;
  4272 
  4273 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4274 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4275 
  4276 
  4277 *** FOL and ZF ***
  4278 
  4279 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4280   with `addloop' of the simplifier to faciliate case splitting in premises.
  4281 
  4282 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4283 in HOL, they strip ALL and --> from proved theorems;
  4284 
  4285 
  4286 
  4287 New in Isabelle94-8 (May 1997)
  4288 ------------------------------
  4289 
  4290 *** General Changes ***
  4291 
  4292 * new utilities to build / run / maintain Isabelle etc. (in parts
  4293 still somewhat experimental); old Makefiles etc. still functional;
  4294 
  4295 * new 'Isabelle System Manual';
  4296 
  4297 * INSTALL text, together with ./configure and ./build scripts;
  4298 
  4299 * reimplemented type inference for greater efficiency, better error
  4300 messages and clean internal interface;
  4301 
  4302 * prlim command for dealing with lots of subgoals (an easier way of
  4303 setting goals_limit);
  4304 
  4305 
  4306 *** Syntax ***
  4307 
  4308 * supports alternative (named) syntax tables (parser and pretty
  4309 printer); internal interface is provided by add_modesyntax(_i);
  4310 
  4311 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4312 be used in conjunction with the Isabelle symbol font; uses the
  4313 "symbols" syntax table;
  4314 
  4315 * added token_translation interface (may translate name tokens in
  4316 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4317 the current print_mode); IMPORTANT: user print translation functions
  4318 are responsible for marking newly introduced bounds
  4319 (Syntax.mark_boundT);
  4320 
  4321 * token translations for modes "xterm" and "xterm_color" that display
  4322 names in bold, underline etc. or colors (which requires a color
  4323 version of xterm);
  4324 
  4325 * infixes may now be declared with names independent of their syntax;
  4326 
  4327 * added typed_print_translation (like print_translation, but may
  4328 access type of constant);
  4329 
  4330 
  4331 *** Classical Reasoner ***
  4332 
  4333 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4334 some limitations.  Blast_tac...
  4335   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4336   + ignores elimination rules that don't have the correct format
  4337         (the conclusion MUST be a formula variable)
  4338   + ignores types, which can make HOL proofs fail
  4339   + rules must not require higher-order unification, e.g. apply_type in ZF
  4340     [message "Function Var's argument not a bound variable" relates to this]
  4341   + its proof strategy is more general but can actually be slower
  4342 
  4343 * substitution with equality assumptions no longer permutes other
  4344 assumptions;
  4345 
  4346 * minor changes in semantics of addafter (now called addaltern); renamed
  4347 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4348 (and access functions for it);
  4349 
  4350 * improved combination of classical reasoner and simplifier:
  4351   + functions for handling clasimpsets
  4352   + improvement of addss: now the simplifier is called _after_ the
  4353     safe steps.
  4354   + safe variant of addss called addSss: uses safe simplifications
  4355     _during_ the safe steps. It is more complete as it allows multiple
  4356     instantiations of unknowns (e.g. with slow_tac).
  4357 
  4358 *** Simplifier ***
  4359 
  4360 * added interface for simplification procedures (functions that
  4361 produce *proven* rewrite rules on the fly, depending on current
  4362 redex);
  4363 
  4364 * ordering on terms as parameter (used for ordered rewriting);
  4365 
  4366 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4367 
  4368 * the solver is now split into a safe and an unsafe part.
  4369 This should be invisible for the normal user, except that the
  4370 functions setsolver and addsolver have been renamed to setSolver and
  4371 addSolver; added safe_asm_full_simp_tac;
  4372 
  4373 
  4374 *** HOL ***
  4375 
  4376 * a generic induction tactic `induct_tac' which works for all datatypes and
  4377 also for type `nat';
  4378 
  4379 * a generic case distinction tactic `exhaust_tac' which works for all
  4380 datatypes and also for type `nat';
  4381 
  4382 * each datatype comes with a function `size';
  4383 
  4384 * patterns in case expressions allow tuple patterns as arguments to
  4385 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4386 
  4387 * primrec now also works with type nat;
  4388 
  4389 * recdef: a new declaration form, allows general recursive functions to be
  4390 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4391 
  4392 * the constant for negation has been renamed from "not" to "Not" to
  4393 harmonize with FOL, ZF, LK, etc.;
  4394 
  4395 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4396 infinite lists;
  4397 
  4398 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4399 
  4400 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4401 problems in commutative rings, using axiomatic type classes for + and *;
  4402 
  4403 * more examples in HOL/MiniML and HOL/Auth;
  4404 
  4405 * more default rewrite rules for quantifiers, union/intersection;
  4406 
  4407 * a new constant `arbitrary == @x.False';
  4408 
  4409 * HOLCF/IOA replaces old HOL/IOA;
  4410 
  4411 * HOLCF changes: derived all rules and arities
  4412   + axiomatic type classes instead of classes
  4413   + typedef instead of faking type definitions
  4414   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4415   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4416   + eliminated the types void, one, tr
  4417   + use unit lift and bool lift (with translations) instead of one and tr
  4418   + eliminated blift from Lift3.thy (use Def instead of blift)
  4419   all eliminated rules are derived as theorems --> no visible changes ;
  4420 
  4421 
  4422 *** ZF ***
  4423 
  4424 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4425 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4426 as ZF_cs addSIs [equalityI];
  4427 
  4428 
  4429 
  4430 New in Isabelle94-7 (November 96)
  4431 ---------------------------------
  4432 
  4433 * allowing negative levels (as offsets) in prlev and choplev;
  4434 
  4435 * super-linear speedup for large simplifications;
  4436 
  4437 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4438 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4439 FAIL); can suppress it using the command Delsimps (ex_simps @
  4440 all_simps); De Morgan laws are also now included, by default;
  4441 
  4442 * improved printing of ==>  :  ~:
  4443 
  4444 * new object-logic "Sequents" adds linear logic, while replacing LK
  4445 and Modal (thanks to Sara Kalvala);
  4446 
  4447 * HOL/Auth: correctness proofs for authentication protocols;
  4448 
  4449 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4450 examples on HOL/Auth);
  4451 
  4452 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4453 the rewriter and classical reasoner simultaneously;
  4454 
  4455 * function uresult no longer returns theorems in "standard" format;
  4456 regain previous version by: val uresult = standard o uresult;
  4457 
  4458 
  4459 
  4460 New in Isabelle94-6
  4461 -------------------
  4462 
  4463 * oracles -- these establish an interface between Isabelle and trusted
  4464 external reasoners, which may deliver results as theorems;
  4465 
  4466 * proof objects (in particular record all uses of oracles);
  4467 
  4468 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4469 
  4470 * "constdefs" section in theory files;
  4471 
  4472 * "primrec" section (HOL) no longer requires names;
  4473 
  4474 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4475 
  4476 
  4477 
  4478 New in Isabelle94-5
  4479 -------------------
  4480 
  4481 * reduced space requirements;
  4482 
  4483 * automatic HTML generation from theories;
  4484 
  4485 * theory files no longer require "..." (quotes) around most types;
  4486 
  4487 * new examples, including two proofs of the Church-Rosser theorem;
  4488 
  4489 * non-curried (1994) version of HOL is no longer distributed;
  4490 
  4491 
  4492 
  4493 New in Isabelle94-4
  4494 -------------------
  4495 
  4496 * greatly reduced space requirements;
  4497 
  4498 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4499 
  4500 * searchable theorem database (see the section "Retrieving theorems" on
  4501 page 8 of the Reference Manual);
  4502 
  4503 * new examples, including Grabczewski's monumental case study of the
  4504 Axiom of Choice;
  4505 
  4506 * The previous version of HOL renamed to Old_HOL;
  4507 
  4508 * The new version of HOL (previously called CHOL) uses a curried syntax
  4509 for functions.  Application looks like f a b instead of f(a,b);
  4510 
  4511 * Mutually recursive inductive definitions finally work in HOL;
  4512 
  4513 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4514 translates to the operator "split";
  4515 
  4516 
  4517 
  4518 New in Isabelle94-3
  4519 -------------------
  4520 
  4521 * new infix operator, addss, allowing the classical reasoner to
  4522 perform simplification at each step of its search.  Example:
  4523         fast_tac (cs addss ss)
  4524 
  4525 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4526 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4527 look like (a,b) instead of <a,b>;
  4528 
  4529 * PLEASE NOTE: CHOL will eventually replace HOL!
  4530 
  4531 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4532 It translates to the operator "split".  A new theory of integers is available;
  4533 
  4534 * In ZF, integer numerals now denote two's-complement binary integers.
  4535 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4536 
  4537 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4538 of the Axiom of Choice;
  4539 
  4540 
  4541 
  4542 New in Isabelle94-2
  4543 -------------------
  4544 
  4545 * Significantly faster resolution;
  4546 
  4547 * the different sections in a .thy file can now be mixed and repeated
  4548 freely;
  4549 
  4550 * Database of theorems for FOL, HOL and ZF.  New
  4551 commands including qed, qed_goal and bind_thm store theorems in the database.
  4552 
  4553 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4554 a given theory (thms_of), or find out what theory a theorem was proved in
  4555 (theory_of_thm);
  4556 
  4557 * Bugs fixed in the inductive definition and datatype packages;
  4558 
  4559 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4560 and HOL_dup_cs obsolete;
  4561 
  4562 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4563 have been removed;
  4564 
  4565 * Simpler definition of function space in ZF;
  4566 
  4567 * new results about cardinal and ordinal arithmetic in ZF;
  4568 
  4569 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4570 types;
  4571 
  4572 
  4573 $Id$