NEWS
author haftmann
Thu Apr 26 13:32:59 2007 +0200 (2007-04-26)
changeset 22799 ed7d53db2170
parent 22754 9947ae4792a0
child 22826 0f4c501a691e
permissions -rw-r--r--
moved code generation pretty integers and characters to separate theories
     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 * code generator: 
    67   - Isar "definition"s and primitive instance definitions are added explicitly
    68     to the table of defining equations
    69   - primitive definitions are not used as defining equations by default any longer
    70   - defining equations are now definitly restricted to meta "==" and object
    71         equality "="
    72   - HOL theories have been adopted accordingly
    73 
    74 * class_package.ML offers a combination of axclasses and locales to
    75 achieve Haskell-like type classes in Isabelle. See
    76 HOL/ex/Classpackage.thy for examples.
    77 
    78 * Yet another code generator framework allows to generate executable
    79 code for ML and Haskell (including "class"es). A short usage sketch:
    80 
    81     internal compilation:
    82         code_gen <list of constants (term syntax)> (SML #)
    83     writing SML code to a file:
    84         code_gen <list of constants (term syntax)> (SML <filename>)
    85     writing OCaml code to a file:
    86         code_gen <list of constants (term syntax)> (OCaml <filename>)
    87     writing Haskell code to a bunch of files:
    88         code_gen <list of constants (term syntax)> (Haskell <filename>)
    89 
    90 Reasonable default setup of framework in HOL/Main.
    91 
    92 Theorem attributs for selecting and transforming function equations theorems:
    93 
    94     [code fun]:       select a theorem as function equation for a specific constant
    95     [code nofun]:     deselect a theorem as function equation for a specific constant
    96     [code inline]:    select an equation theorem for unfolding (inlining) in place
    97     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    98 
    99 User-defined serializations (target in {SML, OCaml, Haskell}):
   100 
   101     code_const <and-list of constants (term syntax)>
   102       {(target) <and-list of const target syntax>}+
   103 
   104     code_type <and-list of type constructors>
   105       {(target) <and-list of type target syntax>}+
   106 
   107     code_instance <and-list of instances>
   108       {(target)}+
   109         where instance ::= <type constructor> :: <class>
   110 
   111     code_class <and_list of classes>
   112       {(target) <and-list of class target syntax>}+
   113         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   114 
   115 code_instance and code_class only apply to target Haskell.
   116 
   117 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   118 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   119 
   120 * Command 'no_translations' removes translation rules from theory
   121 syntax.
   122 
   123 * Overloaded definitions are now actually checked for acyclic
   124 dependencies.  The overloading scheme is slightly more general than
   125 that of Haskell98, although Isabelle does not demand an exact
   126 correspondence to type class and instance declarations.
   127 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   128 exotic versions of overloading -- at the discretion of the user!
   129 
   130 Polymorphic constants are represented via type arguments, i.e. the
   131 instantiation that matches an instance against the most general
   132 declaration given in the signature.  For example, with the declaration
   133 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   134 as c(nat).  Overloading is essentially simultaneous structural
   135 recursion over such type arguments.  Incomplete specification patterns
   136 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   137 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   138 Command 'print_theory' outputs the normalized system of recursive
   139 equations, see section "definitions".
   140 
   141 * Isar: improper proof element 'guess' is like 'obtain', but derives
   142 the obtained context from the course of reasoning!  For example:
   143 
   144   assume "EX x y. A x & B y"   -- "any previous fact"
   145   then guess x and y by clarify
   146 
   147 This technique is potentially adventurous, depending on the facts and
   148 proof tools being involved here.
   149 
   150 * Isar: known facts from the proof context may be specified as literal
   151 propositions, using ASCII back-quote syntax.  This works wherever
   152 named facts used to be allowed so far, in proof commands, proof
   153 methods, attributes etc.  Literal facts are retrieved from the context
   154 according to unification of type and term parameters.  For example,
   155 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   156 theorems in the current context, then these are valid literal facts:
   157 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   158 
   159 There is also a proof method "fact" which does the same composition
   160 for explicit goal states, e.g. the following proof texts coincide with
   161 certain special cases of literal facts:
   162 
   163   have "A" by fact                 ==  note `A`
   164   have "A ==> B" by fact           ==  note `A ==> B`
   165   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   166   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   167 
   168 * Isar: ":" (colon) is no longer a symbolic identifier character in
   169 outer syntax.  Thus symbolic identifiers may be used without
   170 additional white space in declarations like this: ``assume *: A''.
   171 
   172 * Isar: 'print_facts' prints all local facts of the current context,
   173 both named and unnamed ones.
   174 
   175 * Isar: 'def' now admits simultaneous definitions, e.g.:
   176 
   177   def x == "t" and y == "u"
   178 
   179 * Isar: added command 'unfolding', which is structurally similar to
   180 'using', but affects both the goal state and facts by unfolding given
   181 rewrite rules.  Thus many occurrences of the 'unfold' method or
   182 'unfolded' attribute may be replaced by first-class proof text.
   183 
   184 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   185 and command 'unfolding' now all support object-level equalities
   186 (potentially conditional).  The underlying notion of rewrite rule is
   187 analogous to the 'rule_format' attribute, but *not* that of the
   188 Simplifier (which is usually more generous).
   189 
   190 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   191 method expression within a sandbox consisting of the first N
   192 sub-goals, which need to exist.  For example, ``simp_all [3]''
   193 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   194 simplifies all new goals that emerge from applying rule foo to the
   195 originally first one.
   196 
   197 * Isar: schematic goals are no longer restricted to higher-order
   198 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   199 expected.
   200 
   201 * Isar: the conclusion of a long theorem statement is now either
   202 'shows' (a simultaneous conjunction, as before), or 'obtains'
   203 (essentially a disjunction of cases with local parameters and
   204 assumptions).  The latter allows to express general elimination rules
   205 adequately; in this notation common elimination rules look like this:
   206 
   207   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   208     assumes "EX x. P x"
   209     obtains x where "P x"
   210 
   211   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   212     assumes "A & B"
   213     obtains A and B
   214 
   215   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   216     assumes "A | B"
   217     obtains
   218       A
   219     | B
   220 
   221 The subsequent classical rules even refer to the formal "thesis"
   222 explicitly:
   223 
   224   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   225     obtains "~ thesis"
   226 
   227   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   228     obtains "thesis ==> something"
   229 
   230 The actual proof of an 'obtains' statement is analogous to that of the
   231 Isar proof element 'obtain', only that there may be several cases.
   232 Optional case names may be specified in parentheses; these will be
   233 available both in the present proof and as annotations in the
   234 resulting rule, for later use with the 'cases' method (cf. attribute
   235 case_names).
   236 
   237 * Isar: the assumptions of a long theorem statement are available as
   238 "assms" fact in the proof context.  This is more appropriate than the
   239 (historical) "prems", which refers to all assumptions of the current
   240 context, including those from the target locale, proof body etc.
   241 
   242 * Isar: 'print_statement' prints theorems from the current theory or
   243 proof context in long statement form, according to the syntax of a
   244 top-level lemma.
   245 
   246 * Isar: 'obtain' takes an optional case name for the local context
   247 introduction rule (default "that").
   248 
   249 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   250 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   251 to occur.
   252 
   253 * Pure: syntax "CONST name" produces a fully internalized constant
   254 according to the current context.  This is particularly useful for
   255 syntax translations that should refer to internal constant
   256 representations independently of name spaces.
   257 
   258 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   259 instead of "FOO ". This allows multiple binder declarations to coexist
   260 in the same context.  INCOMPATIBILITY.
   261 
   262 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   263 primitive that also works in a locale context (both for constants and
   264 fixed variables).  Type declaration and internal syntactic
   265 representation of given constants retrieved from the context.
   266 
   267 * Isar/locales: new derived specification elements 'axiomatization',
   268 'definition', 'abbreviation', which support type-inference, admit
   269 object-level specifications (equality, equivalence).  See also the
   270 isar-ref manual.  Examples:
   271 
   272   axiomatization
   273     eq  (infix "===" 50) where
   274     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   275 
   276   definition "f x y = x + y + 1"
   277   definition g where "g x = f x x"
   278 
   279   abbreviation
   280     neq  (infix "=!=" 50) where
   281     "x =!= y == ~ (x === y)"
   282 
   283 These specifications may be also used in a locale context.  Then the
   284 constants being introduced depend on certain fixed parameters, and the
   285 constant name is qualified by the locale base name.  An internal
   286 abbreviation takes care for convenient input and output, making the
   287 parameters implicit and using the original short name.  See also
   288 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   289 entities from a monomorphic theory.
   290 
   291 Presently, abbreviations are only available 'in' a target locale, but
   292 not inherited by general import expressions.  Also note that
   293 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   294 'translations' in common applications.
   295 
   296 Concrete syntax is attached to specified constants in internal form,
   297 independently of name spaces.  The parse tree representation is
   298 slightly different -- use 'notation' instead of raw 'syntax', and
   299 'translations' with explicit "CONST" markup to accommodate this.
   300 
   301 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   302 the current context.  Print mode "no_abbrevs" prevents inversion of
   303 abbreviations on output.
   304 
   305 * Isar/locales: improved parameter handling:
   306 - use of locales "var" and "struct" no longer necessary;
   307 - parameter renamings are no longer required to be injective.
   308   This enables, for example, to define a locale for endomorphisms thus:
   309   locale endom = homom mult mult h.
   310 
   311 * Isar/locales: changed the way locales with predicates are defined.
   312 Instead of accumulating the specification, the imported expression is
   313 now an interpretation.  INCOMPATIBILITY: different normal form of
   314 locale expressions.  In particular, in interpretations of locales with
   315 predicates, goals repesenting already interpreted fragments are not
   316 removed automatically.  Use methods `intro_locales' and
   317 `unfold_locales'; see below.
   318 
   319 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   320 provide backward reasoning on locales predicates.  The methods are
   321 aware of interpretations and discharge corresponding goals.
   322 `intro_locales' is less aggressive then `unfold_locales' and does not
   323 unfold predicates to assumptions.
   324 
   325 * Isar/locales: the order in which locale fragments are accumulated
   326 has changed.  This enables to override declarations from fragments due
   327 to interpretations -- for example, unwanted simp rules.
   328 
   329 * Provers/induct: improved internal context management to support
   330 local fixes and defines on-the-fly.  Thus explicit meta-level
   331 connectives !! and ==> are rarely required anymore in inductive goals
   332 (using object-logic connectives for this purpose has been long
   333 obsolete anyway).  The subsequent proof patterns illustrate advanced
   334 techniques of natural induction; general datatypes and inductive sets
   335 work analogously (see also src/HOL/Lambda for realistic examples).
   336 
   337 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   338 parameters:
   339 
   340   lemma
   341     fixes n :: nat and x :: 'a
   342     assumes a: "A n x"
   343     shows "P n x"
   344     using a                     -- {* make induct insert fact a *}
   345   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   346     case 0
   347     show ?case sorry
   348   next
   349     case (Suc n)
   350     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   351     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   352     show ?case sorry
   353   qed
   354 
   355 (2) This is how to perform induction over ``expressions of a certain
   356 form'', using a locally defined inductive parameter n == "a x"
   357 together with strengthening (the latter is usually required to get
   358 sufficiently flexible induction hypotheses):
   359 
   360   lemma
   361     fixes a :: "'a => nat"
   362     assumes a: "A (a x)"
   363     shows "P (a x)"
   364     using a
   365   proof (induct n == "a x" arbitrary: x)
   366     ...
   367 
   368 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   369 particular technique.
   370 
   371 (3) This is how to perform existential reasoning ('obtains' or
   372 'obtain') by induction, while avoiding explicit object-logic
   373 encodings:
   374 
   375   lemma
   376     fixes n :: nat
   377     obtains x :: 'a where "P n x" and "Q n x"
   378   proof (induct n arbitrary: thesis)
   379     case 0
   380     obtain x where "P 0 x" and "Q 0 x" sorry
   381     then show thesis by (rule 0)
   382   next
   383     case (Suc n)
   384     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   385     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   386     then show thesis by (rule Suc.prems)
   387   qed
   388 
   389 Here the 'arbitrary: thesis' specification essentially modifies the
   390 scope of the formal thesis parameter, in order to the get the whole
   391 existence statement through the induction as expected.
   392 
   393 * Provers/induct: mutual induction rules are now specified as a list
   394 of rule sharing the same induction cases.  HOL packages usually
   395 provide foo_bar.inducts for mutually defined items foo and bar
   396 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   397 specify mutual induction rules differently, i.e. like this:
   398 
   399   (induct rule: foo_bar.inducts)
   400   (induct set: foo bar)
   401   (induct type: foo bar)
   402 
   403 The ML function ProjectRule.projections turns old-style rules into the
   404 new format.
   405 
   406 * Provers/induct: improved handling of simultaneous goals.  Instead of
   407 introducing object-level conjunction, the statement is now split into
   408 several conclusions, while the corresponding symbolic cases are
   409 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   410 explicitly.  For example:
   411 
   412   lemma
   413     fixes n :: nat
   414     shows "P n" and "Q n"
   415   proof (induct n)
   416     case 0 case 1
   417     show "P 0" sorry
   418   next
   419     case 0 case 2
   420     show "Q 0" sorry
   421   next
   422     case (Suc n) case 1
   423     note `P n` and `Q n`
   424     show "P (Suc n)" sorry
   425   next
   426     case (Suc n) case 2
   427     note `P n` and `Q n`
   428     show "Q (Suc n)" sorry
   429   qed
   430 
   431 The split into subcases may be deferred as follows -- this is
   432 particularly relevant for goal statements with local premises.
   433 
   434   lemma
   435     fixes n :: nat
   436     shows "A n ==> P n" and "B n ==> Q n"
   437   proof (induct n)
   438     case 0
   439     {
   440       case 1
   441       note `A 0`
   442       show "P 0" sorry
   443     next
   444       case 2
   445       note `B 0`
   446       show "Q 0" sorry
   447     }
   448   next
   449     case (Suc n)
   450     note `A n ==> P n` and `B n ==> Q n`
   451     {
   452       case 1
   453       note `A (Suc n)`
   454       show "P (Suc n)" sorry
   455     next
   456       case 2
   457       note `B (Suc n)`
   458       show "Q (Suc n)" sorry
   459     }
   460   qed
   461 
   462 If simultaneous goals are to be used with mutual rules, the statement
   463 needs to be structured carefully as a two-level conjunction, using
   464 lists of propositions separated by 'and':
   465 
   466   lemma
   467     shows "a : A ==> P1 a"
   468           "a : A ==> P2 a"
   469       and "b : B ==> Q1 b"
   470           "b : B ==> Q2 b"
   471           "b : B ==> Q3 b"
   472   proof (induct set: A B)
   473 
   474 * Provers/induct: support coinduction as well.  See
   475 src/HOL/Library/Coinductive_List.thy for various examples.
   476 
   477 * Attribute "symmetric" produces result with standardized schematic
   478 variables (index 0).  Potential INCOMPATIBILITY.
   479 
   480 * Simplifier: by default the simplifier trace only shows top level
   481 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   482 default. Thus there is less danger of being flooded by the trace. The
   483 trace indicates where parts have been suppressed.
   484   
   485 * Provers/classical: removed obsolete classical version of elim_format
   486 attribute; classical elim/dest rules are now treated uniformly when
   487 manipulating the claset.
   488 
   489 * Provers/classical: stricter checks to ensure that supplied intro,
   490 dest and elim rules are well-formed; dest and elim rules must have at
   491 least one premise.
   492 
   493 * Provers/classical: attributes dest/elim/intro take an optional
   494 weight argument for the rule (just as the Pure versions).  Weights are
   495 ignored by automated tools, but determine the search order of single
   496 rule steps.
   497 
   498 * Syntax: input syntax now supports dummy variable binding "%_. b",
   499 where the body does not mention the bound variable.  Note that dummy
   500 patterns implicitly depend on their context of bounds, which makes
   501 "{_. _}" match any set comprehension as expected.  Potential
   502 INCOMPATIBILITY -- parse translations need to cope with syntactic
   503 constant "_idtdummy" in the binding position.
   504 
   505 * Syntax: removed obsolete syntactic constant "_K" and its associated
   506 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   507 for example "A -> B" => "Pi A (%_. B)".
   508 
   509 * Pure: 'class_deps' command visualizes the subclass relation, using
   510 the graph browser tool.
   511 
   512 * Pure: 'print_theory' now suppresses entities with internal name
   513 (trailing "_") by default; use '!' option for full details.
   514 
   515 
   516 *** HOL ***
   517 
   518 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   519     when generating code.
   520 
   521 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   522     when generating code.
   523 
   524 * Library/Commutative_Ring.thy: switched from recdef to function package;
   525     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   526 
   527 * Some steps towards more uniform lattice theory development in HOL.
   528 
   529     constants "meet" and "join" now named "inf" and "sup"
   530     constant "Meet" now named "Inf"
   531 
   532     classes "meet_semilorder" and "join_semilorder" now named
   533       "lower_semilattice" and "upper_semilattice"
   534     class "lorder" now named "lattice"
   535     class "comp_lat" now named "complete_lattice"
   536 
   537     Instantiation of lattice classes allows explicit definitions
   538     for "inf" and "sup" operations.
   539 
   540   INCOMPATIBILITY. Theorem renames:
   541 
   542     meet_left_le            ~> inf_le1
   543     meet_right_le           ~> inf_le2
   544     join_left_le            ~> sup_ge1
   545     join_right_le           ~> sup_ge2
   546     meet_join_le            ~> inf_sup_ord
   547     le_meetI                ~> le_infI
   548     join_leI                ~> le_supI
   549     le_meet                 ~> le_inf_iff
   550     le_join                 ~> ge_sup_conv
   551     meet_idempotent         ~> inf_idem
   552     join_idempotent         ~> sup_idem
   553     meet_comm               ~> inf_commute
   554     join_comm               ~> sup_commute
   555     meet_leI1               ~> le_infI1
   556     meet_leI2               ~> le_infI2
   557     le_joinI1               ~> le_supI1
   558     le_joinI2               ~> le_supI2
   559     meet_assoc              ~> inf_assoc
   560     join_assoc              ~> sup_assoc
   561     meet_left_comm          ~> inf_left_commute
   562     meet_left_idempotent    ~> inf_left_idem
   563     join_left_comm          ~> sup_left_commute
   564     join_left_idempotent    ~> sup_left_idem
   565     meet_aci                ~> inf_aci
   566     join_aci                ~> sup_aci
   567     le_def_meet             ~> le_iff_inf
   568     le_def_join             ~> le_iff_sup
   569     join_absorp2            ~> sup_absorb2
   570     join_absorp1            ~> sup_absorb1
   571     meet_absorp1            ~> inf_absorb1
   572     meet_absorp2            ~> inf_absorb2
   573     meet_join_absorp        ~> inf_sup_absorb
   574     join_meet_absorp        ~> sup_inf_absorb
   575     distrib_join_le         ~> distrib_sup_le
   576     distrib_meet_le         ~> distrib_inf_le
   577 
   578     add_meet_distrib_left   ~> add_inf_distrib_left
   579     add_join_distrib_left   ~> add_sup_distrib_left
   580     is_join_neg_meet        ~> is_join_neg_inf
   581     is_meet_neg_join        ~> is_meet_neg_sup
   582     add_meet_distrib_right  ~> add_inf_distrib_right
   583     add_join_distrib_right  ~> add_sup_distrib_right
   584     add_meet_join_distribs  ~> add_sup_inf_distribs
   585     join_eq_neg_meet        ~> sup_eq_neg_inf
   586     meet_eq_neg_join        ~> inf_eq_neg_sup
   587     add_eq_meet_join        ~> add_eq_inf_sup
   588     meet_0_imp_0            ~> inf_0_imp_0
   589     join_0_imp_0            ~> sup_0_imp_0
   590     meet_0_eq_0             ~> inf_0_eq_0
   591     join_0_eq_0             ~> sup_0_eq_0
   592     neg_meet_eq_join        ~> neg_inf_eq_sup
   593     neg_join_eq_meet        ~> neg_sup_eq_inf
   594     join_eq_if              ~> sup_eq_if
   595 
   596     mono_meet               ~> mono_inf
   597     mono_join               ~> mono_sup
   598     meet_bool_eq            ~> inf_bool_eq
   599     join_bool_eq            ~> sup_bool_eq
   600     meet_fun_eq             ~> inf_fun_eq
   601     join_fun_eq             ~> sup_fun_eq
   602     meet_set_eq             ~> inf_set_eq
   603     join_set_eq             ~> sup_set_eq
   604     meet1_iff               ~> inf1_iff
   605     meet2_iff               ~> inf2_iff
   606     meet1I                  ~> inf1I
   607     meet2I                  ~> inf2I
   608     meet1D1                 ~> inf1D1
   609     meet2D1                 ~> inf2D1
   610     meet1D2                 ~> inf1D2
   611     meet2D2                 ~> inf2D2
   612     meet1E                  ~> inf1E
   613     meet2E                  ~> inf2E
   614     join1_iff               ~> sup1_iff
   615     join2_iff               ~> sup2_iff
   616     join1I1                 ~> sup1I1
   617     join2I1                 ~> sup2I1
   618     join1I1                 ~> sup1I1
   619     join2I2                 ~> sup1I2
   620     join1CI                 ~> sup1CI
   621     join2CI                 ~> sup2CI
   622     join1E                  ~> sup1E
   623     join2E                  ~> sup2E
   624 
   625     is_meet_Meet            ~> is_meet_Inf
   626     Meet_bool_def           ~> Inf_bool_def
   627     Meet_fun_def            ~> Inf_fun_def
   628     Meet_greatest           ~> Inf_greatest
   629     Meet_lower              ~> Inf_lower
   630     Meet_set_def            ~> Inf_set_def
   631 
   632     listsp_meetI            ~> listsp_infI
   633     listsp_meet_eq          ~> listsp_inf_eq
   634 
   635     meet_min                ~> inf_min
   636     join_max                ~> sup_max
   637 
   638 * Class (axclass + locale) "preorder" and "linear": facts "refl", "trans" and
   639 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   640 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   641 
   642 * Addes class (axclass + locale) "preorder" as superclass of "order";
   643 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   644 proofs changed.
   645 
   646 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   647 INCOMPATIBILITY.
   648 
   649 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   650 INCOMPATIBILITY.
   651 
   652 * Added syntactic class "size"; overloaded constant "size" now has
   653 type "'a::size ==> bool"
   654 
   655 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   656 dvd" to "Divides.div", "Divides.mod" and "Divides.dvd". INCOMPATIBILITY.
   657 
   658 * Added method "lexicographic_order" automatically synthesizes
   659 termination relations as lexicographic combinations of size measures
   660 -- 'function' package.
   661 
   662 * HOL/records: generalised field-update to take a function on the
   663 field rather than the new value: r(|A := x|) is translated to A_update
   664 (K x) r The K-combinator that is internally used is called K_record.
   665 INCOMPATIBILITY: Usage of the plain update functions has to be
   666 adapted.
   667  
   668 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   669 0 * x = 0, which are required for a semiring.  Richer structures do
   670 not inherit from semiring_0 anymore, because this property is a
   671 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   672 semiring_0, there is more to prove, but this is mostly trivial.
   673 
   674 * axclass "recpower" was generalized to arbitrary monoids, not just
   675 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   676 commutativity or a semiring property, add the corresponding classes.
   677 
   678 * Unified locale partial_order with class definition (cf. theory
   679 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   680 
   681 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   682 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   683 Isar level, use abbreviations instead.
   684 
   685 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   686 rarely occuring name references (e.g. ``List.op mem.simps'') require
   687 renaming (e.g. ``List.memberl.simps'').
   688 
   689 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   690 INCOMPATIBILITY.
   691 
   692 * Added theory Code_Generator providing class 'eq', allowing for code
   693 generation with polymorphic equality.
   694 
   695 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   696 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   697 significant changes for setting up numeral syntax for types:
   698 
   699   - new constants Numeral.pred and Numeral.succ instead
   700       of former Numeral.bin_pred and Numeral.bin_succ.
   701   - Use integer operations instead of bin_add, bin_mult and so on.
   702   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   703   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   704 
   705 See HOL/Integ/IntArith.thy for an example setup.
   706 
   707 * New top level command 'normal_form' computes the normal form of a
   708 term that may contain free variables. For example ``normal_form
   709 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   710 suitable for heavy-duty computations because the functions are
   711 compiled to ML first.
   712 
   713 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   714 25 like -->); output depends on the "iff" print_mode, the default is
   715 "A = B" (with priority 50).
   716 
   717 * Renamed constants in HOL.thy and Orderings.thy:
   718     op +   ~> HOL.plus
   719     op -   ~> HOL.minus
   720     uminus ~> HOL.uminus
   721     op *   ~> HOL.times
   722     op <   ~> Orderings.less
   723     op <=  ~> Orderings.less_eq
   724 
   725 Adaptions may be required in the following cases:
   726 
   727 a) User-defined constants using any of the names "plus", "minus", "times",
   728 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   729 may go wrong.
   730 INCOMPATIBILITY: use more specific names.
   731 
   732 b) Variables named "plus", "minus", "times", "less", "less_eq"
   733 INCOMPATIBILITY: use more specific names.
   734 
   735 c) Permutative equations (e.g. "a + b = b + a")
   736 Since the change of names also changes the order of terms, permutative
   737 rewrite rules may get applied in a different order. Experience shows that
   738 this is rarely the case (only two adaptions in the whole Isabelle
   739 distribution).
   740 INCOMPATIBILITY: rewrite proofs
   741 
   742 d) ML code directly refering to constant names
   743 This in general only affects hand-written proof tactics, simprocs and so on.
   744 INCOMPATIBILITY: grep your sourcecode and replace names.
   745 
   746 * Relations less (<) and less_eq (<=) are also available on type bool.
   747 Modified syntax to disallow nesting without explicit parentheses,
   748 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   749 
   750 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   751 
   752 * Relation composition operator "op O" now has precedence 75 and binds
   753 stronger than union and intersection. INCOMPATIBILITY.
   754 
   755 * The old set interval syntax "{m..n(}" (and relatives) has been
   756 removed.  Use "{m..<n}" (and relatives) instead.
   757 
   758 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   759 "t = s" to False (by simproc "neq_simproc").  For backward
   760 compatibility this can be disabled by ML "reset use_neq_simproc".
   761 
   762 * "m dvd n" where m and n are numbers is evaluated to True/False by
   763 simp.
   764 
   765 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   766 
   767 * Theorem setsum_mult renamed to setsum_right_distrib.
   768 
   769 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   770 ``rule'' method.
   771 
   772 * Reimplemented methods ``sat'' and ``satx'', with several
   773 improvements: goals no longer need to be stated as "<prems> ==>
   774 False", equivalences (i.e. "=" on type bool) are handled, variable
   775 names of the form "lit_<n>" are no longer reserved, significant
   776 speedup.
   777 
   778 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   779 zChaff is still supported as well.
   780 
   781 * 'inductive' and 'datatype': provide projections of mutual rules,
   782 bundled as foo_bar.inducts;
   783 
   784 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   785 Library.
   786 
   787 * Library: moved theory Accessible_Part to main HOL.
   788 
   789 * Library: added theory Coinductive_List of potentially infinite lists
   790 as greatest fixed-point.
   791 
   792 * Library: added theory AssocList which implements (finite) maps as
   793 association lists.
   794 
   795 * Added proof method ``evaluation'' for efficiently solving a goal
   796 (i.e. a boolean expression) by compiling it to ML. The goal is
   797 "proved" (via an oracle) if it evaluates to True.
   798 
   799 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   800 also when invoked by the simplifier.  This results in the simplifier
   801 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   802 fast_arith_split_limit to 0 to obtain the old behavior.
   803 
   804 * Support for hex (0x20) and binary (0b1001) numerals.
   805 
   806 * New method: reify eqs (t), where eqs are equations for an
   807 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   808 parameter, computes a term s::'b and a list xs::'a list and proves the
   809 theorem I xs s = t. This is also known as reification or quoting. The
   810 resulting theorem is applied to the subgoal to substitute t with I xs
   811 s.  If t is omitted, the subgoal itself is reified.
   812 
   813 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   814 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   815 where f is supposed to be a computable function (in the sense of code
   816 generattion). The method uses reify to compute s and xs as above then
   817 applies corr_thm and uses normalization by evaluation to "prove" f s =
   818 r and finally gets the theorem t = r, which is again applied to the
   819 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   820 
   821 * Reflection: Automatic refification now handels binding, an example
   822 is available in HOL/ex/ReflectionEx.thy
   823 
   824 
   825 *** HOL-Algebra ***
   826 
   827 * Formalisation of ideals and the quotient construction over rings.
   828 
   829 * Order and lattice theory no longer based on records.
   830 INCOMPATIBILITY.
   831 
   832 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   833 greatest_closed.  INCOMPATIBILITY.
   834 
   835 * Method algebra is now set up via an attribute.  For examples see
   836 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   837 of algebraic structures.
   838 
   839 * Renamed theory CRing to Ring.
   840 
   841 
   842 *** HOL-Complex ***
   843 
   844 * Theory Real: new method ferrack implements quantifier elimination
   845 for linear arithmetic over the reals. The quantifier elimination
   846 feature is used only for decision, for compatibility with arith. This
   847 means a goal is either solved or left unchanged, no simplification.
   848 
   849 * Real: New axiomatic classes formalize real normed vector spaces and
   850 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   851 and norm :: 'a => real.
   852 
   853 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   854 from reals into other types. The overloaded constant Reals :: 'a set
   855 is now defined as range of_real; potential INCOMPATIBILITY.
   856 
   857 * Hyperreal: Several constants that previously worked only for the
   858 reals have been generalized, so they now work over arbitrary vector
   859 spaces. Type annotations may need to be added in some cases; potential
   860 INCOMPATIBILITY.
   861 
   862   Infinitesimal  :: ('a::real_normed_vector) star set"
   863   HFinite        :: ('a::real_normed_vector) star set"
   864   HInfinite      :: ('a::real_normed_vector) star set"
   865   approx         :: ('a::real_normed_vector) star => 'a star => bool
   866   monad          :: ('a::real_normed_vector) star => 'a star set
   867   galaxy         :: ('a::real_normed_vector) star => 'a star set
   868   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   869   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   870   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   871   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   872   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   873   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   874   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   875 
   876 * Complex: Some complex-specific constants are now abbreviations for
   877 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   878 hnorm.  Other constants have been entirely removed in favor of the
   879 polymorphic versions (INCOMPATIBILITY):
   880 
   881   approx        <-- capprox
   882   HFinite       <-- CFinite
   883   HInfinite     <-- CInfinite
   884   Infinitesimal <-- CInfinitesimal
   885   monad         <-- cmonad
   886   galaxy        <-- cgalaxy
   887   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   888   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   889   (ns)deriv     <-- (ns)cderiv
   890 
   891 
   892 *** ML ***
   893 
   894 * ML within Isar: antiquotations allow to embed statically-checked
   895 formal entities in the source, referring to the context available at
   896 compile-time.  For example:
   897 
   898 ML {* @{typ "'a => 'b"} *}
   899 ML {* @{term "%x. x"} *}
   900 ML {* @{prop "x == y"} *}
   901 ML {* @{ctyp "'a => 'b"} *}
   902 ML {* @{cterm "%x. x"} *}
   903 ML {* @{cprop "x == y"} *}
   904 ML {* @{thm asm_rl} *}
   905 ML {* @{thms asm_rl} *}
   906 ML {* @{const_name c} *}
   907 ML {* @{const_syntax c} *}
   908 ML {* @{context} *}
   909 ML {* @{theory} *}
   910 ML {* @{theory Pure} *}
   911 ML {* @{simpset} *}
   912 ML {* @{claset} *}
   913 ML {* @{clasimpset} *}
   914 
   915 The same works for sources being ``used'' within an Isar context.
   916 
   917 * ML in Isar: improved error reporting; extra verbosity with
   918 Toplevel.debug enabled.
   919 
   920 * Pure/library:
   921 
   922   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   923   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   924 
   925 The semantics of "burrow" is: "take a function with *simulatanously*
   926 transforms a list of value, and apply it *simulatanously* to a list of
   927 list of values of the appropriate type". Compare this with "map" which
   928 would *not* apply its argument function simulatanously but in
   929 sequence; "fold_burrow" has an additional context.
   930 
   931 * Pure/library: functions map2 and fold2 with curried syntax for
   932 simultanous mapping and folding:
   933 
   934     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   935     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   936 
   937 * Pure/library: indexed lists - some functions in the Isabelle library
   938 treating lists over 'a as finite mappings from [0...n] to 'a have been
   939 given more convenient names and signatures reminiscent of similar
   940 functions for alists, tables, etc:
   941 
   942   val nth: 'a list -> int -> 'a 
   943   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   944   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   945 
   946 Note that fold_index starts counting at index 0, not 1 like foldln
   947 used to.
   948 
   949 * Pure/library: added general ``divide_and_conquer'' combinator on
   950 lists.
   951 
   952 * Pure/General/table.ML: the join operations now works via exceptions
   953 DUP/SAME instead of type option.  This is simpler in simple cases, and
   954 admits slightly more efficient complex applications.
   955 
   956 * Pure: datatype Context.generic joins theory/Proof.context and
   957 provides some facilities for code that works in either kind of
   958 context, notably GenericDataFun for uniform theory and proof data.
   959 
   960 * Pure: 'advanced' translation functions (parse_translation etc.) now
   961 use Context.generic instead of just theory.
   962 
   963 * Pure: simplified internal attribute type, which is now always
   964 Context.generic * thm -> Context.generic * thm.  Global (theory)
   965 vs. local (Proof.context) attributes have been discontinued, while
   966 minimizing code duplication.  Thm.rule_attribute and
   967 Thm.declaration_attribute build canonical attributes; see also
   968 structure Context for further operations on Context.generic, notably
   969 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   970 declarations and definitions.
   971 
   972 * Pure/kernel: consts certification ignores sort constraints given in
   973 signature declarations.  (This information is not relevant to the
   974 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   975 potential INCOMPATIBILITY.
   976 
   977 * Pure: axiomatic type classes are now purely definitional, with
   978 explicit proofs of class axioms and super class relations performed
   979 internally.  See Pure/axclass.ML for the main internal interfaces --
   980 notably AxClass.define_class supercedes AxClass.add_axclass, and
   981 AxClass.axiomatize_class/classrel/arity supercede
   982 Sign.add_classes/classrel/arities.
   983 
   984 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   985 global/local versions on theory vs. Proof.context have been
   986 discontinued; Attrib.syntax and Method.syntax have been adapted
   987 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   988 attributes, methods, etc.
   989 
   990 * Pure: several functions of signature "... -> theory -> theory * ..."
   991 have been reoriented to "... -> theory -> ... * theory" in order to
   992 allow natural usage in combination with the ||>, ||>>, |-> and
   993 fold_map combinators.
   994 
   995 * Pure: official theorem names (closed derivations) and additional
   996 comments (tags) are now strictly separate.  Name hints -- which are
   997 maintained as tags -- may be attached any time without affecting the
   998 derivation.
   999 
  1000 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1001 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1002 achieve the old behaviour.
  1003 
  1004 * Pure: the "Goal" constant is now called "prop", supporting a
  1005 slightly more general idea of ``protecting'' meta-level rule
  1006 statements.
  1007 
  1008 * Pure: Logic.(un)varify only works in a global context, which is now
  1009 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1010 Logic.legacy_(un)varify as temporary workaround.
  1011 
  1012 * Pure: structure Name provides scalable operations for generating
  1013 internal variable names, notably Name.variants etc.  This replaces
  1014 some popular functions from term.ML:
  1015 
  1016   Term.variant		->  Name.variant
  1017   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1018   Term.invent_names	->  Name.invent_list
  1019 
  1020 Note that low-level renaming rarely occurs in new code -- operations
  1021 from structure Variable are used instead (see below).
  1022 
  1023 * Pure: structure Variable provides fundamental operations for proper
  1024 treatment of fixed/schematic variables in a context.  For example,
  1025 Variable.import introduces fixes for schematics of given facts and
  1026 Variable.export reverses the effect (up to renaming) -- this replaces
  1027 various freeze_thaw operations.
  1028 
  1029 * Pure: structure Goal provides simple interfaces for
  1030 init/conclude/finish and tactical prove operations (replacing former
  1031 Tactic.prove).  Goal.prove is the canonical way to prove results
  1032 within a given context; Goal.prove_global is a degraded version for
  1033 theory level goals, including a global Drule.standard.  Note that
  1034 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1035 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1036 in a locale context).
  1037 
  1038 * Isar: simplified treatment of user-level errors, using exception
  1039 ERROR of string uniformly.  Function error now merely raises ERROR,
  1040 without any side effect on output channels.  The Isar toplevel takes
  1041 care of proper display of ERROR exceptions.  ML code may use plain
  1042 handle/can/try; cat_error may be used to concatenate errors like this:
  1043 
  1044   ... handle ERROR msg => cat_error msg "..."
  1045 
  1046 Toplevel ML code (run directly or through the Isar toplevel) may be
  1047 embedded into the Isar toplevel with exception display/debug like
  1048 this:
  1049 
  1050   Isar.toplevel (fn () => ...)
  1051 
  1052 INCOMPATIBILITY, removed special transform_error facilities, removed
  1053 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1054 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1055 -- use plain ERROR instead.
  1056 
  1057 * Isar: theory setup now has type (theory -> theory), instead of a
  1058 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1059 
  1060 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1061 subject to ProofContext.debug/verbose flags.
  1062 
  1063 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1064 theory before entering a proof state.  Transactions now always see a
  1065 quasi-functional intermediate checkpoint, both in interactive and
  1066 batch mode.
  1067 
  1068 * Simplifier: the simpset of a running simplification process now
  1069 contains a proof context (cf. Simplifier.the_context), which is the
  1070 very context that the initial simpset has been retrieved from (by
  1071 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1072 (solver, looper etc.) may depend on arbitrary proof data.
  1073 
  1074 * Simplifier.inherit_context inherits the proof context (plus the
  1075 local bounds) of the current simplification process; any simproc
  1076 etc. that calls the Simplifier recursively should do this!  Removed
  1077 former Simplifier.inherit_bounds, which is already included here --
  1078 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1079 specify an explicit context using Simplifier.context/theory_context.
  1080 
  1081 * Simplifier/Classical Reasoner: more abstract interfaces
  1082 change_simpset/claset for modifying the simpset/claset reference of a
  1083 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1084 INCOMPATIBILITY.
  1085 
  1086 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1087 "Trueprop" etc.
  1088 
  1089 
  1090 *** System ***
  1091 
  1092 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1093 locations -- now includes the Isabelle version identifier as well.
  1094 This simplifies use of multiple Isabelle installations.
  1095 
  1096 * isabelle-process: option -S (secure mode) disables some critical
  1097 operations, notably runtime compilation and evaluation of ML source
  1098 code.
  1099 
  1100 
  1101 New in Isabelle2005 (October 2005)
  1102 ----------------------------------
  1103 
  1104 *** General ***
  1105 
  1106 * Theory headers: the new header syntax for Isar theories is
  1107 
  1108   theory <name>
  1109   imports <theory1> ... <theoryN>
  1110   uses <file1> ... <fileM>
  1111   begin
  1112 
  1113 where the 'uses' part is optional.  The previous syntax
  1114 
  1115   theory <name> = <theory1> + ... + <theoryN>:
  1116 
  1117 will disappear in the next release.  Use isatool fixheaders to convert
  1118 existing theory files.  Note that there is no change in ancient
  1119 non-Isar theories now, but these will disappear soon.
  1120 
  1121 * Theory loader: parent theories can now also be referred to via
  1122 relative and absolute paths.
  1123 
  1124 * Command 'find_theorems' searches for a list of criteria instead of a
  1125 list of constants. Known criteria are: intro, elim, dest, name:string,
  1126 simp:term, and any term. Criteria can be preceded by '-' to select
  1127 theorems that do not match. Intro, elim, dest select theorems that
  1128 match the current goal, name:s selects theorems whose fully qualified
  1129 name contain s, and simp:term selects all simplification rules whose
  1130 lhs match term.  Any other term is interpreted as pattern and selects
  1131 all theorems matching the pattern. Available in ProofGeneral under
  1132 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1133 
  1134   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1135 
  1136 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1137 matching the current goal as introduction rule and not having "HOL."
  1138 in their name (i.e. not being defined in theory HOL).
  1139 
  1140 * Command 'thms_containing' has been discontinued in favour of
  1141 'find_theorems'; INCOMPATIBILITY.
  1142 
  1143 * Communication with Proof General is now 8bit clean, which means that
  1144 Unicode text in UTF-8 encoding may be used within theory texts (both
  1145 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1146 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1147 
  1148   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1149   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1150 
  1151 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1152 Classical Reasoner.  Typical big applications run around 2 times
  1153 faster.
  1154 
  1155 
  1156 *** Document preparation ***
  1157 
  1158 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1159 of raw sources.  Only those symbols that do not require additional
  1160 LaTeX packages (depending on comments in isabellesym.sty) are
  1161 displayed properly, everything else is left verbatim.  isatool display
  1162 and isatool print are used as front ends (these are subject to the
  1163 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1164 
  1165 * Command tags control specific markup of certain regions of text,
  1166 notably folding and hiding.  Predefined tags include "theory" (for
  1167 theory begin and end), "proof" for proof commands, and "ML" for
  1168 commands involving ML code; the additional tags "visible" and
  1169 "invisible" are unused by default.  Users may give explicit tag
  1170 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1171 interpretation of tags is determined by the LaTeX job during document
  1172 preparation: see option -V of isatool usedir, or options -n and -t of
  1173 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1174 \isadroptag.
  1175 
  1176 Several document versions may be produced at the same time via isatool
  1177 usedir (the generated index.html will link all of them).  Typical
  1178 specifications include ''-V document=theory,proof,ML'' to present
  1179 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1180 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1181 these parts without any formal replacement text.  The Isabelle site
  1182 default settings produce ''document'' and ''outline'' versions as
  1183 specified above.
  1184 
  1185 * Several new antiquotations:
  1186 
  1187   @{term_type term} prints a term with its type annotated;
  1188 
  1189   @{typeof term} prints the type of a term;
  1190 
  1191   @{const const} is the same as @{term const}, but checks that the
  1192   argument is a known logical constant;
  1193 
  1194   @{term_style style term} and @{thm_style style thm} print a term or
  1195   theorem applying a "style" to it
  1196 
  1197   @{ML text}
  1198 
  1199 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1200 definitions, equations, inequations etc., 'concl' printing only the
  1201 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1202 to print the specified premise.  TermStyle.add_style provides an ML
  1203 interface for introducing further styles.  See also the "LaTeX Sugar"
  1204 document practical applications.  The ML antiquotation prints
  1205 type-checked ML expressions verbatim.
  1206 
  1207 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1208 and 'text' support optional locale specification '(in loc)', which
  1209 specifies the default context for interpreting antiquotations.  For
  1210 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1211 
  1212 * Option 'locale=NAME' of antiquotations specifies an alternative
  1213 context interpreting the subsequent argument.  For example: @{thm
  1214 [locale=lattice] inf_assoc}.
  1215 
  1216 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1217 a proof context.
  1218 
  1219 * Proper output of antiquotations for theory commands involving a
  1220 proof context (such as 'locale' or 'theorem (in loc) ...').
  1221 
  1222 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1223 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1224 
  1225 * isatool usedir: new option -C (default true) controls whether option
  1226 -D should include a copy of the original document directory; -C false
  1227 prevents unwanted effects such as copying of administrative CVS data.
  1228 
  1229 
  1230 *** Pure ***
  1231 
  1232 * Considerably improved version of 'constdefs' command.  Now performs
  1233 automatic type-inference of declared constants; additional support for
  1234 local structure declarations (cf. locales and HOL records), see also
  1235 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1236 sequential dependencies of definitions within a single 'constdefs'
  1237 section; moreover, the declared name needs to be an identifier.  If
  1238 all fails, consider to fall back on 'consts' and 'defs' separately.
  1239 
  1240 * Improved indexed syntax and implicit structures.  First of all,
  1241 indexed syntax provides a notational device for subscripted
  1242 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1243 expressions.  Secondly, in a local context with structure
  1244 declarations, number indexes \<^sub>n or the empty index (default
  1245 number 1) refer to a certain fixed variable implicitly; option
  1246 show_structs controls printing of implicit structures.  Typical
  1247 applications of these concepts involve record types and locales.
  1248 
  1249 * New command 'no_syntax' removes grammar declarations (and
  1250 translations) resulting from the given syntax specification, which is
  1251 interpreted in the same manner as for the 'syntax' command.
  1252 
  1253 * 'Advanced' translation functions (parse_translation etc.) may depend
  1254 on the signature of the theory context being presently used for
  1255 parsing/printing, see also isar-ref manual.
  1256 
  1257 * Improved 'oracle' command provides a type-safe interface to turn an
  1258 ML expression of type theory -> T -> term into a primitive rule of
  1259 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1260 is already included here); see also FOL/ex/IffExample.thy;
  1261 INCOMPATIBILITY.
  1262 
  1263 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1264 before); "cI" is no longer bound, use "c.intro" instead.
  1265 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1266 axclasses vs. locales.
  1267 
  1268 * Improved internal renaming of symbolic identifiers -- attach primes
  1269 instead of base 26 numbers.
  1270 
  1271 * New flag show_question_marks controls printing of leading question
  1272 marks in schematic variable names.
  1273 
  1274 * In schematic variable names, *any* symbol following \<^isub> or
  1275 \<^isup> is now treated as part of the base name.  For example, the
  1276 following works without printing of awkward ".0" indexes:
  1277 
  1278   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1279     by simp
  1280 
  1281 * Inner syntax includes (*(*nested*) comments*).
  1282 
  1283 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1284 annotations as "(00...)".
  1285 
  1286 * Clear separation of logical types and nonterminals, where the latter
  1287 may only occur in 'syntax' specifications or type abbreviations.
  1288 Before that distinction was only partially implemented via type class
  1289 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1290 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1291 exotic syntax specifications may require further adaption
  1292 (e.g. Cube/Cube.thy).
  1293 
  1294 * Removed obsolete type class "logic", use the top sort {} instead.
  1295 Note that non-logical types should be declared as 'nonterminals'
  1296 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1297 specifications.
  1298 
  1299 * Attributes 'induct' and 'cases': type or set names may now be
  1300 locally fixed variables as well.
  1301 
  1302 * Simplifier: can now control the depth to which conditional rewriting
  1303 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1304 Limit.
  1305 
  1306 * Simplifier: simplification procedures may now take the current
  1307 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1308 interface), which is very useful for calling the Simplifier
  1309 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1310 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1311 low-level mk_simproc no longer applies Logic.varify internally, to
  1312 allow for use in a context of fixed variables.
  1313 
  1314 * thin_tac now works even if the assumption being deleted contains !!
  1315 or ==>.  More generally, erule now works even if the major premise of
  1316 the elimination rule contains !! or ==>.
  1317 
  1318 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1319 
  1320 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1321 from Pure, which contains all common declarations already.  Both
  1322 theories are defined via plain Isabelle/Isar .thy files.
  1323 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1324 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1325 use isatool fixcpure to adapt your theory and ML sources.
  1326 
  1327 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1328 selections of theorems in named facts via index ranges.
  1329 
  1330 * 'print_theorems': in theory mode, really print the difference
  1331 wrt. the last state (works for interactive theory development only),
  1332 in proof mode print all local facts (cf. 'print_facts');
  1333 
  1334 * 'hide': option '(open)' hides only base names.
  1335 
  1336 * More efficient treatment of intermediate checkpoints in interactive
  1337 theory development.
  1338 
  1339 * Code generator is now invoked via code_module (incremental code
  1340 generation) and code_library (modular code generation, ML structures
  1341 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1342 must be quoted when used as identifiers.
  1343 
  1344 * New 'value' command for reading, evaluating and printing terms using
  1345 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1346 quoted when used as identifier.
  1347 
  1348 
  1349 *** Locales ***
  1350 
  1351 * New commands for the interpretation of locale expressions in
  1352 theories (1), locales (2) and proof contexts (3).  These generate
  1353 proof obligations from the expression specification.  After the
  1354 obligations have been discharged, theorems of the expression are added
  1355 to the theory, target locale or proof context.  The synopsis of the
  1356 commands is a follows:
  1357 
  1358   (1) interpretation expr inst
  1359   (2) interpretation target < expr
  1360   (3) interpret expr inst
  1361 
  1362 Interpretation in theories and proof contexts require a parameter
  1363 instantiation of terms from the current context.  This is applied to
  1364 specifications and theorems of the interpreted expression.
  1365 Interpretation in locales only permits parameter renaming through the
  1366 locale expression.  Interpretation is smart in that interpretations
  1367 that are active already do not occur in proof obligations, neither are
  1368 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1369 inspect active interpretations of a particular locale.  For details,
  1370 see the Isar Reference manual.  Examples can be found in
  1371 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1372 
  1373 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1374 'interpret' instead.
  1375 
  1376 * New context element 'constrains' for adding type constraints to
  1377 parameters.
  1378 
  1379 * Context expressions: renaming of parameters with syntax
  1380 redeclaration.
  1381 
  1382 * Locale declaration: 'includes' disallowed.
  1383 
  1384 * Proper static binding of attribute syntax -- i.e. types / terms /
  1385 facts mentioned as arguments are always those of the locale definition
  1386 context, independently of the context of later invocations.  Moreover,
  1387 locale operations (renaming and type / term instantiation) are applied
  1388 to attribute arguments as expected.
  1389 
  1390 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1391 actual attributes; rare situations may require Attrib.attribute to
  1392 embed those attributes into Attrib.src that lack concrete syntax.
  1393 Attribute implementations need to cooperate properly with the static
  1394 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1395 Attrib.XXX_thm etc. already do the right thing without further
  1396 intervention.  Only unusual applications -- such as "where" or "of"
  1397 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1398 on the context and the facts involved -- may have to assign parsed
  1399 values to argument tokens explicitly.
  1400 
  1401 * Changed parameter management in theorem generation for long goal
  1402 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1403 theorem statement in rare situations.
  1404 
  1405 * Locale inspection command 'print_locale' omits notes elements.  Use
  1406 'print_locale!' to have them included in the output.
  1407 
  1408 
  1409 *** Provers ***
  1410 
  1411 * Provers/hypsubst.ML: improved version of the subst method, for
  1412 single-step rewriting: it now works in bound variable contexts. New is
  1413 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1414 rewrite a different subterm than the original subst method, which is
  1415 still available as 'simplesubst'.
  1416 
  1417 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1418 and quasi orders.
  1419 
  1420 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1421 reflexive-transitive closure of relations.
  1422 
  1423 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1424 limit (previously hard-coded with a value of 20) user-definable.
  1425 
  1426 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1427 is peformed already.  Object-logics merely need to finish their
  1428 initial simpset configuration as before.  INCOMPATIBILITY.
  1429 
  1430 
  1431 *** HOL ***
  1432 
  1433 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1434 
  1435   syntax (epsilon)
  1436     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1437 
  1438 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1439 and x-symbol; use option '-m epsilon' to get it actually printed.
  1440 Moreover, the mathematically important symbolic identifier \<epsilon>
  1441 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1442 
  1443 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1444 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1445 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1446 support corresponding Isar calculations.
  1447 
  1448 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1449 instead of ":".
  1450 
  1451 * theory SetInterval: changed the syntax for open intervals:
  1452 
  1453   Old       New
  1454   {..n(}    {..<n}
  1455   {)n..}    {n<..}
  1456   {m..n(}   {m..<n}
  1457   {)m..n}   {m<..n}
  1458   {)m..n(}  {m<..<n}
  1459 
  1460 The old syntax is still supported but will disappear in the next
  1461 release.  For conversion use the following Emacs search and replace
  1462 patterns (these are not perfect but work quite well):
  1463 
  1464   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1465   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1466 
  1467 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1468 equalities in commutative rings; method 'algebra' provides a generic
  1469 interface.
  1470 
  1471 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1472 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1473 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1474 be a tuple pattern.
  1475 
  1476 Some new syntax forms are available:
  1477 
  1478   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1479   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1480   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1481   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1482 
  1483 The latter form "\<Sum>x < k. e" used to be based on a separate
  1484 function "Summation", which has been discontinued.
  1485 
  1486 * theory Finite_Set: in structured induction proofs, the insert case
  1487 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1488 (insert F x)'.
  1489 
  1490 * The 'refute' command has been extended to support a much larger
  1491 fragment of HOL, including axiomatic type classes, constdefs and
  1492 typedefs, inductive datatypes and recursion.
  1493 
  1494 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1495 Requires zChaff with proof generation to be installed.  See
  1496 HOL/ex/SAT_Examples.thy for examples.
  1497 
  1498 * Datatype induction via method 'induct' now preserves the name of the
  1499 induction variable. For example, when proving P(xs::'a list) by
  1500 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1501 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1502 in unstructured proof scripts.
  1503 
  1504 * Reworked implementation of records.  Improved scalability for
  1505 records with many fields, avoiding performance problems for type
  1506 inference. Records are no longer composed of nested field types, but
  1507 of nested extension types. Therefore the record type only grows linear
  1508 in the number of extensions and not in the number of fields.  The
  1509 top-level (users) view on records is preserved.  Potential
  1510 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1511 old record representation. The type generated for a record is called
  1512 <record_name>_ext_type.
  1513 
  1514 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1515 proofs triggered by a record definition or a simproc (if
  1516 quick_and_dirty is enabled).  Definitions of large records can take
  1517 quite long.
  1518 
  1519 New simproc record_upd_simproc for simplification of multiple record
  1520 updates enabled by default.  Moreover, trivial updates are also
  1521 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1522 occasionally, since simplification is more powerful by default.
  1523 
  1524 * typedef: proper support for polymorphic sets, which contain extra
  1525 type-variables in the term.
  1526 
  1527 * Simplifier: automatically reasons about transitivity chains
  1528 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1529 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1530 old proofs break occasionally as simplification may now solve more
  1531 goals than previously.
  1532 
  1533 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1534 present.  Works for all partial orders (class "order"), in particular
  1535 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1536 just like y <= x.
  1537 
  1538 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1539 bound variable or a constant then the let is unfolded.  Otherwise
  1540 first a is simplified to b, and then f b is simplified to g. If
  1541 possible we abstract b from g arriving at "let x = b in h x",
  1542 otherwise we unfold the let and arrive at g.  The simproc can be
  1543 enabled/disabled by the reference use_let_simproc.  Potential
  1544 INCOMPATIBILITY since simplification is more powerful by default.
  1545 
  1546 * Classical reasoning: the meson method now accepts theorems as arguments.
  1547 
  1548 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1549 jobs to provide advice on the provability of subgoals.
  1550 
  1551 * Theory OrderedGroup and Ring_and_Field: various additions and
  1552 improvements to faciliate calculations involving equalities and
  1553 inequalities.
  1554 
  1555 The following theorems have been eliminated or modified
  1556 (INCOMPATIBILITY):
  1557 
  1558   abs_eq             now named abs_of_nonneg
  1559   abs_of_ge_0        now named abs_of_nonneg
  1560   abs_minus_eq       now named abs_of_nonpos
  1561   imp_abs_id         now named abs_of_nonneg
  1562   imp_abs_neg_id     now named abs_of_nonpos
  1563   mult_pos           now named mult_pos_pos
  1564   mult_pos_le        now named mult_nonneg_nonneg
  1565   mult_pos_neg_le    now named mult_nonneg_nonpos
  1566   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1567   mult_neg           now named mult_neg_neg
  1568   mult_neg_le        now named mult_nonpos_nonpos
  1569 
  1570 * Theory Parity: added rules for simplifying exponents.
  1571 
  1572 * Theory List:
  1573 
  1574 The following theorems have been eliminated or modified
  1575 (INCOMPATIBILITY):
  1576 
  1577   list_all_Nil       now named list_all.simps(1)
  1578   list_all_Cons      now named list_all.simps(2)
  1579   list_all_conv      now named list_all_iff
  1580   set_mem_eq         now named mem_iff
  1581 
  1582 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1583 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1584 
  1585 
  1586 *** HOL-Complex ***
  1587 
  1588 * Theory RealDef: better support for embedding natural numbers and
  1589 integers in the reals.
  1590 
  1591 The following theorems have been eliminated or modified
  1592 (INCOMPATIBILITY):
  1593 
  1594   exp_ge_add_one_self  now requires no hypotheses
  1595   real_of_int_add      reversed direction of equality (use [symmetric])
  1596   real_of_int_minus    reversed direction of equality (use [symmetric])
  1597   real_of_int_diff     reversed direction of equality (use [symmetric])
  1598   real_of_int_mult     reversed direction of equality (use [symmetric])
  1599 
  1600 * Theory RComplete: expanded support for floor and ceiling functions.
  1601 
  1602 * Theory Ln is new, with properties of the natural logarithm
  1603 
  1604 * Hyperreal: There is a new type constructor "star" for making
  1605 nonstandard types.  The old type names are now type synonyms:
  1606 
  1607   hypreal = real star
  1608   hypnat = nat star
  1609   hcomplex = complex star
  1610 
  1611 * Hyperreal: Many groups of similarly-defined constants have been
  1612 replaced by polymorphic versions (INCOMPATIBILITY):
  1613 
  1614   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1615 
  1616   starset      <-- starsetNat, starsetC
  1617   *s*          <-- *sNat*, *sc*
  1618   starset_n    <-- starsetNat_n, starsetC_n
  1619   *sn*         <-- *sNatn*, *scn*
  1620   InternalSets <-- InternalNatSets, InternalCSets
  1621 
  1622   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1623   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1624   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1625   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1626   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1627 
  1628 * Hyperreal: Many type-specific theorems have been removed in favor of
  1629 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1630 
  1631   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1632   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1633   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1634   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1635   right_minus <-- hypreal_add_minus
  1636   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1637   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1638   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1639   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1640   mult_1_right <-- hcomplex_mult_one_right
  1641   mult_zero_left <-- hcomplex_mult_zero_left
  1642   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1643   right_distrib <-- hypnat_add_mult_distrib2
  1644   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1645   right_inverse <-- hypreal_mult_inverse
  1646   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1647   order_refl <-- {hypreal,hypnat}_le_refl
  1648   order_trans <-- {hypreal,hypnat}_le_trans
  1649   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1650   order_less_le <-- {hypreal,hypnat}_less_le
  1651   linorder_linear <-- {hypreal,hypnat}_le_linear
  1652   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1653   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1654   add_nonneg_nonneg <-- hypreal_le_add_order
  1655 
  1656 * Hyperreal: Separate theorems having to do with type-specific
  1657 versions of constants have been merged into theorems that apply to the
  1658 new polymorphic constants (INCOMPATIBILITY):
  1659 
  1660   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1661   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1662   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1663   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1664   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1665   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1666   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1667   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1668   STAR_diff <-- {STAR,STARC}_diff
  1669   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1670     STARC_hcomplex_of_complex}_image_subset
  1671   starset_n_Un <-- starset{Nat,C}_n_Un
  1672   starset_n_Int <-- starset{Nat,C}_n_Int
  1673   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1674   starset_n_diff <-- starset{Nat,C}_n_diff
  1675   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1676   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1677   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1678   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1679   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1680   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1681   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1682   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1683   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1684   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1685   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1686   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1687   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1688   starfun_diff <-- starfun{C,RC,CR}_diff
  1689   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1690   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1691   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1692   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1693   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1694   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1695   starfun_Id <-- starfunC_Id
  1696   starfun_approx <-- starfun{Nat,CR}_approx
  1697   starfun_capprox <-- starfun{C,RC}_capprox
  1698   starfun_abs <-- starfunNat_rabs
  1699   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1700   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1701   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1702   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1703   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1704   starfun_add_approx <-- starfunCR_add_approx
  1705   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1706   starfun_divide <-- starfun{C,CR,RC}_divide
  1707   starfun_n <-- starfun{Nat,C}_n
  1708   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1709   starfun_n_add <-- starfun{Nat,C}_n_add
  1710   starfun_n_add_minus <-- starfunNat_n_add_minus
  1711   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1712   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1713   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1714 
  1715   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1716   star_n_minus <-- {hypreal,hcomplex}_minus
  1717   star_n_diff <-- {hypreal,hcomplex}_diff
  1718   star_n_mult <-- {hypreal,hcomplex}_mult
  1719   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1720   star_n_le <-- {hypreal,hypnat}_le
  1721   star_n_less <-- {hypreal,hypnat}_less
  1722   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1723   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1724   star_n_abs <-- hypreal_hrabs
  1725   star_n_divide <-- hcomplex_divide
  1726 
  1727   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1728   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1729   star_of_diff <-- hypreal_of_real_diff
  1730   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1731   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1732   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1733   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1734   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1735   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1736   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1737   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1738   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1739   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1740   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1741   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1742   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1743   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1744   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1745   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1746   star_of_power <-- hypreal_of_real_power
  1747   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1748 
  1749 * Hyperreal: new method "transfer" that implements the transfer
  1750 principle of nonstandard analysis. With a subgoal that mentions
  1751 nonstandard types like "'a star", the command "apply transfer"
  1752 replaces it with an equivalent one that mentions only standard types.
  1753 To be successful, all free variables must have standard types; non-
  1754 standard variables must have explicit universal quantifiers.
  1755 
  1756 * Hyperreal: A theory of Taylor series.
  1757 
  1758 
  1759 *** HOLCF ***
  1760 
  1761 * Discontinued special version of 'constdefs' (which used to support
  1762 continuous functions) in favor of the general Pure one with full
  1763 type-inference.
  1764 
  1765 * New simplification procedure for solving continuity conditions; it
  1766 is much faster on terms with many nested lambda abstractions (cubic
  1767 instead of exponential time).
  1768 
  1769 * New syntax for domain package: selector names are now optional.
  1770 Parentheses should be omitted unless argument is lazy, for example:
  1771 
  1772   domain 'a stream = cons "'a" (lazy "'a stream")
  1773 
  1774 * New command 'fixrec' for defining recursive functions with pattern
  1775 matching; defining multiple functions with mutual recursion is also
  1776 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1777 sinr, or any data constructor defined by the domain package. The given
  1778 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1779 syntax and examples.
  1780 
  1781 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1782 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1783 but the proof obligation additionally includes an admissibility
  1784 requirement. The packages generate instances of class cpo or pcpo,
  1785 with continuity and strictness theorems for Rep and Abs.
  1786 
  1787 * HOLCF: Many theorems have been renamed according to a more standard naming
  1788 scheme (INCOMPATIBILITY):
  1789 
  1790   foo_inject:  "foo$x = foo$y ==> x = y"
  1791   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1792   foo_less:    "(foo$x << foo$y) = (x << y)"
  1793   foo_strict:  "foo$UU = UU"
  1794   foo_defined: "... ==> foo$x ~= UU"
  1795   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1796 
  1797 
  1798 *** ZF ***
  1799 
  1800 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1801 including the First Isomorphism Theorem (on quotienting by the kernel
  1802 of a homomorphism).
  1803 
  1804 * ZF/Simplifier: install second copy of type solver that actually
  1805 makes use of TC rules declared to Isar proof contexts (or locales);
  1806 the old version is still required for ML proof scripts.
  1807 
  1808 
  1809 *** Cube ***
  1810 
  1811 * Converted to Isar theory format; use locales instead of axiomatic
  1812 theories.
  1813 
  1814 
  1815 *** ML ***
  1816 
  1817 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1818 for ||>, ||>>, |>>,
  1819 
  1820 * Pure/library.ML no longer defines its own option datatype, but uses
  1821 that of the SML basis, which has constructors NONE and SOME instead of
  1822 None and Some, as well as exception Option.Option instead of OPTION.
  1823 The functions the, if_none, is_some, is_none have been adapted
  1824 accordingly, while Option.map replaces apsome.
  1825 
  1826 * Pure/library.ML: the exception LIST has been given up in favour of
  1827 the standard exceptions Empty and Subscript, as well as
  1828 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1829 superceded by the standard hd and tl functions etc.
  1830 
  1831 A number of basic list functions are no longer exported to the ML
  1832 toplevel, as they are variants of predefined functions.  The following
  1833 suggests how one can translate existing code:
  1834 
  1835     rev_append xs ys = List.revAppend (xs, ys)
  1836     nth_elem (i, xs) = List.nth (xs, i)
  1837     last_elem xs = List.last xs
  1838     flat xss = List.concat xss
  1839     seq fs = List.app fs
  1840     partition P xs = List.partition P xs
  1841     mapfilter f xs = List.mapPartial f xs
  1842 
  1843 * Pure/library.ML: several combinators for linear functional
  1844 transformations, notably reverse application and composition:
  1845 
  1846   x |> f                f #> g
  1847   (x, y) |-> f          f #-> g
  1848 
  1849 * Pure/library.ML: introduced/changed precedence of infix operators:
  1850 
  1851   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1852   infix 2 ?;
  1853   infix 3 o oo ooo oooo;
  1854   infix 4 ~~ upto downto;
  1855 
  1856 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1857 infix operators.
  1858 
  1859 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1860 fold_map support linear functional transformations and nesting.  For
  1861 example:
  1862 
  1863   fold f [x1, ..., xN] y =
  1864     y |> f x1 |> ... |> f xN
  1865 
  1866   (fold o fold) f [xs1, ..., xsN] y =
  1867     y |> fold f xs1 |> ... |> fold f xsN
  1868 
  1869   fold f [x1, ..., xN] =
  1870     f x1 #> ... #> f xN
  1871 
  1872   (fold o fold) f [xs1, ..., xsN] =
  1873     fold f xs1 #> ... #> fold f xsN
  1874 
  1875 * Pure/library.ML: the following selectors on type 'a option are
  1876 available:
  1877 
  1878   the:               'a option -> 'a  (*partial*)
  1879   these:             'a option -> 'a  where 'a = 'b list
  1880   the_default: 'a -> 'a option -> 'a
  1881   the_list:          'a option -> 'a list
  1882 
  1883 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1884 basic operations for association lists, following natural argument
  1885 order; moreover the explicit equality predicate passed here avoids
  1886 potentially expensive polymorphic runtime equality checks.
  1887 The old functions may be expressed as follows:
  1888 
  1889   assoc = uncurry (AList.lookup (op =))
  1890   assocs = these oo AList.lookup (op =)
  1891   overwrite = uncurry (AList.update (op =)) o swap
  1892 
  1893 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1894 
  1895   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1896   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1897 
  1898 replacing make_keylist and keyfilter (occassionally used)
  1899 Naive rewrites:
  1900 
  1901   make_keylist = AList.make
  1902   keyfilter = AList.find (op =)
  1903 
  1904 * eq_fst and eq_snd now take explicit equality parameter, thus
  1905   avoiding eqtypes. Naive rewrites:
  1906 
  1907     eq_fst = eq_fst (op =)
  1908     eq_snd = eq_snd (op =)
  1909 
  1910 * Removed deprecated apl and apr (rarely used).
  1911   Naive rewrites:
  1912 
  1913     apl (n, op) =>>= curry op n
  1914     apr (op, m) =>>= fn n => op (n, m)
  1915 
  1916 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1917 provides a reasonably efficient light-weight implementation of sets as
  1918 lists.
  1919 
  1920 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1921 few new operations; existing lookup and update are now curried to
  1922 follow natural argument order (for use with fold etc.);
  1923 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1924 
  1925 * Pure/General: output via the Isabelle channels of
  1926 writeln/warning/error etc. is now passed through Output.output, with a
  1927 hook for arbitrary transformations depending on the print_mode
  1928 (cf. Output.add_mode -- the first active mode that provides a output
  1929 function wins).  Already formatted output may be embedded into further
  1930 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1931 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1932 accommodate easy composition of diagnostic messages etc.  Programmers
  1933 rarely need to care about Output.output or Output.raw at all, with
  1934 some notable exceptions: Output.output is required when bypassing the
  1935 standard channels (writeln etc.), or in token translations to produce
  1936 properly formatted results; Output.raw is required when capturing
  1937 already output material that will eventually be presented to the user
  1938 a second time.  For the default print mode, both Output.output and
  1939 Output.raw have no effect.
  1940 
  1941 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1942 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1943 cumulative results are displayed at the end of a batch session.
  1944 
  1945 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1946 replaced by File.platform_path and File.shell_path (with appropriate
  1947 hooks).  This provides a clean interface for unusual systems where the
  1948 internal and external process view of file names are different.
  1949 
  1950 * Pure: more efficient orders for basic syntactic entities: added
  1951 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1952 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1953 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1954 orders now -- potential INCOMPATIBILITY for code that depends on a
  1955 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1956 Library.sort_strings on result).
  1957 
  1958 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1959 fold_types traverse types/terms from left to right, observing natural
  1960 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1961 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1962 
  1963 * Pure: name spaces have been refined, with significant changes of the
  1964 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1965 to extern(_table).  The plain name entry path is superceded by a
  1966 general 'naming' context, which also includes the 'policy' to produce
  1967 a fully qualified name and external accesses of a fully qualified
  1968 name; NameSpace.extend is superceded by context dependent
  1969 Sign.declare_name.  Several theory and proof context operations modify
  1970 the naming context.  Especially note Theory.restore_naming and
  1971 ProofContext.restore_naming to get back to a sane state; note that
  1972 Theory.add_path is no longer sufficient to recover from
  1973 Theory.absolute_path in particular.
  1974 
  1975 * Pure: new flags short_names (default false) and unique_names
  1976 (default true) for controlling output of qualified names.  If
  1977 short_names is set, names are printed unqualified.  If unique_names is
  1978 reset, the name prefix is reduced to the minimum required to achieve
  1979 the original result when interning again, even if there is an overlap
  1980 with earlier declarations.
  1981 
  1982 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1983 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1984 (useful for printing error messages).  INCOMPATIBILITY.
  1985 
  1986 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1987 Theory.theory are now identified, referring to the universal
  1988 Context.theory (see Pure/context.ML).  Actual signature and theory
  1989 content is managed as theory data.  The old code and interfaces were
  1990 spread over many files and structures; the new arrangement introduces
  1991 considerable INCOMPATIBILITY to gain more clarity:
  1992 
  1993   Context -- theory management operations (name, identity, inclusion,
  1994     parents, ancestors, merge, etc.), plus generic theory data;
  1995 
  1996   Sign -- logical signature and syntax operations (declaring consts,
  1997     types, etc.), plus certify/read for common entities;
  1998 
  1999   Theory -- logical theory operations (stating axioms, definitions,
  2000     oracles), plus a copy of logical signature operations (consts,
  2001     types, etc.); also a few basic management operations (Theory.copy,
  2002     Theory.merge, etc.)
  2003 
  2004 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2005 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2006 for convenience -- they merely return the theory.
  2007 
  2008 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2009 
  2010 * Pure: the Isar proof context type is already defined early in Pure
  2011 as Context.proof (note that ProofContext.context and Proof.context are
  2012 aliases, where the latter is the preferred name).  This enables other
  2013 Isabelle components to refer to that type even before Isar is present.
  2014 
  2015 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2016 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2017 any of these kinds.  For example, Sign.intern typeK is now
  2018 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2019 Theory.hide_types.  Also note that former
  2020 Theory.hide_classes/types/consts are now
  2021 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2022 internalize their arguments!  INCOMPATIBILITY.
  2023 
  2024 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2025 datatype thmref (with constructors Name and NameSelection) instead of
  2026 plain string -- INCOMPATIBILITY;
  2027 
  2028 * Pure: cases produced by proof methods specify options, where NONE
  2029 means to remove case bindings -- INCOMPATIBILITY in
  2030 (RAW_)METHOD_CASES.
  2031 
  2032 * Pure: the following operations retrieve axioms or theorems from a
  2033 theory node or theory hierarchy, respectively:
  2034 
  2035   Theory.axioms_of: theory -> (string * term) list
  2036   Theory.all_axioms_of: theory -> (string * term) list
  2037   PureThy.thms_of: theory -> (string * thm) list
  2038   PureThy.all_thms_of: theory -> (string * thm) list
  2039 
  2040 * Pure: print_tac now outputs the goal through the trace channel.
  2041 
  2042 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2043 Reference Toplevel.debug (default false) controls detailed printing
  2044 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2045 controls execution profiling -- set to 1 for time and 2 for space
  2046 (both increase the runtime).
  2047 
  2048 * Isar session: The initial use of ROOT.ML is now always timed,
  2049 i.e. the log will show the actual process times, in contrast to the
  2050 elapsed wall-clock time that the outer shell wrapper produces.
  2051 
  2052 * Simplifier: improved handling of bound variables (nameless
  2053 representation, avoid allocating new strings).  Simprocs that invoke
  2054 the Simplifier recursively should use Simplifier.inherit_bounds to
  2055 avoid local name clashes.  Failure to do so produces warnings
  2056 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2057 for further details.
  2058 
  2059 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2060 bindings for all theorems stored within a given theory; this may help
  2061 in porting non-Isar theories to Isar ones, while keeping ML proof
  2062 scripts for the time being.
  2063 
  2064 * ML operator HTML.with_charset specifies the charset begin used for
  2065 generated HTML files.  For example:
  2066 
  2067   HTML.with_charset "utf-8" use_thy "Hebrew";
  2068   HTML.with_charset "utf-8" use_thy "Chinese";
  2069 
  2070 
  2071 *** System ***
  2072 
  2073 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2074 isabelle, isatool etc.).
  2075 
  2076 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2077 isatool doc, isatool mkdir, display_drafts etc.).
  2078 
  2079 * isatool usedir: option -f allows specification of the ML file to be
  2080 used by Isabelle; default is ROOT.ML.
  2081 
  2082 * New isatool version outputs the version identifier of the Isabelle
  2083 distribution being used.
  2084 
  2085 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2086 (containing Boolean satisfiability problems) into Isabelle/HOL
  2087 theories.
  2088 
  2089 
  2090 
  2091 New in Isabelle2004 (April 2004)
  2092 --------------------------------
  2093 
  2094 *** General ***
  2095 
  2096 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2097   Replaces linorder.ML.
  2098 
  2099 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2100   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2101   (\<a>...\<z>), are now considered normal letters, and can therefore
  2102   be used anywhere where an ASCII letter (a...zA...Z) has until
  2103   now. COMPATIBILITY: This obviously changes the parsing of some
  2104   terms, especially where a symbol has been used as a binder, say
  2105   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2106   as an identifier.  Fix it by inserting a space around former
  2107   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2108   existing theory and ML files.
  2109 
  2110 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2111 
  2112 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2113   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2114   a normal (but invisible) letter. For multiple letter subscripts repeat
  2115   \<^isub> like this: x\<^isub>1\<^isub>2.
  2116 
  2117 * Pure: There are now sub-/superscripts that can span more than one
  2118   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2119   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2120   superscript. The new control characters are not identifier parts.
  2121 
  2122 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2123   content of "..." to the latex file instead of \isacntrl... . The "..."
  2124   may consist of any printable characters excluding the end bracket >.
  2125 
  2126 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2127   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2128   declare constants "final", which prevents their being given a definition
  2129   later.  It is useful for constants whose behaviour is fixed axiomatically
  2130   rather than definitionally, such as the meta-logic connectives.
  2131 
  2132 * Pure: 'instance' now handles general arities with general sorts
  2133   (i.e. intersections of classes),
  2134 
  2135 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2136   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2137   It can be changed to alter the colors/layout of generated pages.
  2138 
  2139 
  2140 *** Isar ***
  2141 
  2142 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2143   cut_tac, subgoal_tac and thin_tac:
  2144   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2145     locales are no longer forced to write Isar proof scripts.
  2146     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2147     emulations.
  2148   - INCOMPATIBILITY: names of variables to be instantiated may no
  2149     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2150     This is consistent with the instantiation attribute "where".
  2151 
  2152 * Attributes "where" and "of":
  2153   - Now take type variables of instantiated theorem into account when reading
  2154     the instantiation string.  This fixes a bug that caused instantiated
  2155     theorems to have too special types in some circumstances.
  2156   - "where" permits explicit instantiations of type variables.
  2157 
  2158 * Calculation commands "moreover" and "also" no longer interfere with
  2159   current facts ("this"), admitting arbitrary combinations with "then"
  2160   and derived forms.
  2161 
  2162 * Locales:
  2163   - Goal statements involving the context element "includes" no longer
  2164     generate theorems with internal delta predicates (those ending on
  2165     "_axioms") in the premise.
  2166     Resolve particular premise with <locale>.intro to obtain old form.
  2167   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2168     specification and "includes" elements in goal statement.
  2169   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2170     [intro?] and [elim?] (respectively) by default.
  2171   - Experimental command for instantiation of locales in proof contexts:
  2172         instantiate <label>[<attrs>]: <loc>
  2173     Instantiates locale <loc> and adds all its theorems to the current context
  2174     taking into account their attributes.  Label and attrs are optional
  2175     modifiers, like in theorem declarations.  If present, names of
  2176     instantiated theorems are qualified with <label>, and the attributes
  2177     <attrs> are applied after any attributes these theorems might have already.
  2178       If the locale has assumptions, a chained fact of the form
  2179     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2180     are derived.  The command does not support old-style locales declared
  2181     with "locale (open)".
  2182       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2183 
  2184 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2185   (Isar) contexts.
  2186 
  2187 
  2188 *** HOL ***
  2189 
  2190 * Proof import: new image HOL4 contains the imported library from
  2191   the HOL4 system with about 2500 theorems. It is imported by
  2192   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2193   can be used like any other Isabelle image.  See
  2194   HOL/Import/HOL/README for more information.
  2195 
  2196 * Simplifier:
  2197   - Much improved handling of linear and partial orders.
  2198     Reasoners for linear and partial orders are set up for type classes
  2199     "linorder" and "order" respectively, and are added to the default simpset
  2200     as solvers.  This means that the simplifier can build transitivity chains
  2201     to solve goals from the assumptions.
  2202   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2203     of blast or auto after simplification become unnecessary because the goal
  2204     is solved by simplification already.
  2205 
  2206 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2207     all proved in axiomatic type classes for semirings, rings and fields.
  2208 
  2209 * Numerics:
  2210   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2211     now formalized using the Ring_and_Field theory mentioned above.
  2212   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2213     than before, because now they are set up once in a generic manner.
  2214   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2215     Look for the general versions in Ring_and_Field (and Power if they concern
  2216     exponentiation).
  2217 
  2218 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2219 
  2220 * Records:
  2221   - Record types are now by default printed with their type abbreviation
  2222     instead of the list of all field types. This can be configured via
  2223     the reference "print_record_type_abbr".
  2224   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2225     (not enabled by default).
  2226   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2227     EX x. x = sel r to True (not enabled by default).
  2228   - Tactic "record_split_simp_tac" to split and simplify records added.
  2229 
  2230 * 'specification' command added, allowing for definition by
  2231   specification.  There is also an 'ax_specification' command that
  2232   introduces the new constants axiomatically.
  2233 
  2234 * arith(_tac) is now able to generate counterexamples for reals as well.
  2235 
  2236 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2237 
  2238 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2239   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2240 
  2241 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2242   matrix theory to linear programming.
  2243 
  2244 * Unions and Intersections:
  2245   The latex output syntax of UN and INT has been changed
  2246   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2247   i.e. the index formulae has become a subscript.
  2248   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2249 
  2250 * Unions and Intersections over Intervals:
  2251   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2252   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2253   like in normal math, and corresponding versions for < and for intersection.
  2254 
  2255 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2256   lexicographic dictonary ordering has been added as "lexord".
  2257 
  2258 * ML: the legacy theory structures Int and List have been removed. They had
  2259   conflicted with ML Basis Library structures having the same names.
  2260 
  2261 * 'refute' command added to search for (finite) countermodels.  Only works
  2262   for a fragment of HOL.  The installation of an external SAT solver is
  2263   highly recommended.  See "HOL/Refute.thy" for details.
  2264 
  2265 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2266   formulae under an assignment of free variables to random values.
  2267   In contrast to 'refute', it can deal with inductive datatypes,
  2268   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2269   for examples.
  2270 
  2271 
  2272 *** HOLCF ***
  2273 
  2274 * Streams now come with concatenation and are part of the HOLCF image
  2275 
  2276 
  2277 
  2278 New in Isabelle2003 (May 2003)
  2279 ------------------------------
  2280 
  2281 *** General ***
  2282 
  2283 * Provers/simplifier:
  2284 
  2285   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2286     Assumptions are now subject to complete mutual simplification,
  2287     not just from left to right. The simplifier now preserves
  2288     the order of assumptions.
  2289 
  2290     Potential INCOMPATIBILITY:
  2291 
  2292     -- simp sometimes diverges where the old version did
  2293        not, e.g. invoking simp on the goal
  2294 
  2295         [| P (f x); y = x; f x = f y |] ==> Q
  2296 
  2297        now gives rise to the infinite reduction sequence
  2298 
  2299         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2300 
  2301        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2302        kind of problem.
  2303 
  2304     -- Tactics combining classical reasoner and simplification (such as auto)
  2305        are also affected by this change, because many of them rely on
  2306        simp. They may sometimes diverge as well or yield a different numbers
  2307        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2308        in case of problems. Sometimes subsequent calls to the classical
  2309        reasoner will fail because a preceeding call to the simplifier too
  2310        eagerly simplified the goal, e.g. deleted redundant premises.
  2311 
  2312   - The simplifier trace now shows the names of the applied rewrite rules
  2313 
  2314   - You can limit the number of recursive invocations of the simplifier
  2315     during conditional rewriting (where the simplifie tries to solve the
  2316     conditions before applying the rewrite rule):
  2317     ML "simp_depth_limit := n"
  2318     where n is an integer. Thus you can force termination where previously
  2319     the simplifier would diverge.
  2320 
  2321   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2322 
  2323   - No longer aborts on failed congruence proof.  Instead, the
  2324     congruence is ignored.
  2325 
  2326 * Pure: New generic framework for extracting programs from constructive
  2327   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2328   as HOL/Extraction for some case studies.
  2329 
  2330 * Pure: The main goal of the proof state is no longer shown by default, only
  2331 the subgoals. This behaviour is controlled by a new flag.
  2332    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2333 (ML: Proof.show_main_goal).
  2334 
  2335 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2336 rules whose conclusion matches subgoal 1:
  2337       PG menu: Isabelle/Isar -> Show me -> matching rules
  2338 The rules are ordered by how closely they match the subgoal.
  2339 In particular, rules that solve a subgoal outright are displayed first
  2340 (or rather last, the way they are printed).
  2341 (ML: ProofGeneral.print_intros())
  2342 
  2343 * Pure: New flag trace_unify_fail causes unification to print
  2344 diagnostic information (PG: in trace buffer) when it fails. This is
  2345 useful for figuring out why single step proofs like rule, erule or
  2346 assumption failed.
  2347 
  2348 * Pure: Locale specifications now produce predicate definitions
  2349 according to the body of text (covering assumptions modulo local
  2350 definitions); predicate "loc_axioms" covers newly introduced text,
  2351 while "loc" is cumulative wrt. all included locale expressions; the
  2352 latter view is presented only on export into the global theory
  2353 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2354 on the old view without predicates;
  2355 
  2356 * Pure: predefined locales "var" and "struct" are useful for sharing
  2357 parameters (as in CASL, for example); just specify something like
  2358 ``var x + var y + struct M'' as import;
  2359 
  2360 * Pure: improved thms_containing: proper indexing of facts instead of
  2361 raw theorems; check validity of results wrt. current name space;
  2362 include local facts of proof configuration (also covers active
  2363 locales), cover fixed variables in index; may use "_" in term
  2364 specification; an optional limit for the number of printed facts may
  2365 be given (the default is 40);
  2366 
  2367 * Pure: disallow duplicate fact bindings within new-style theory files
  2368 (batch-mode only);
  2369 
  2370 * Provers: improved induct method: assumptions introduced by case
  2371 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2372 the goal statement); "foo" still refers to all facts collectively;
  2373 
  2374 * Provers: the function blast.overloaded has been removed: all constants
  2375 are regarded as potentially overloaded, which improves robustness in exchange
  2376 for slight decrease in efficiency;
  2377 
  2378 * Provers/linorder: New generic prover for transitivity reasoning over
  2379 linear orders.  Note: this prover is not efficient!
  2380 
  2381 * Isar: preview of problems to finish 'show' now produce an error
  2382 rather than just a warning (in interactive mode);
  2383 
  2384 
  2385 *** HOL ***
  2386 
  2387 * arith(_tac)
  2388 
  2389  - Produces a counter example if it cannot prove a goal.
  2390    Note that the counter example may be spurious if the goal is not a formula
  2391    of quantifier-free linear arithmetic.
  2392    In ProofGeneral the counter example appears in the trace buffer.
  2393 
  2394  - Knows about div k and mod k where k is a numeral of type nat or int.
  2395 
  2396  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2397    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2398    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2399 
  2400 * simp's arithmetic capabilities have been enhanced a bit: it now
  2401 takes ~= in premises into account (by performing a case split);
  2402 
  2403 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2404 are distributed over a sum of terms;
  2405 
  2406 * New tactic "trans_tac" and method "trans" instantiate
  2407 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2408 "<=", "<" and "=").
  2409 
  2410 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2411 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2412 
  2413 * 'typedef' command has new option "open" to suppress the set
  2414 definition;
  2415 
  2416 * functions Min and Max on finite sets have been introduced (theory
  2417 Finite_Set);
  2418 
  2419 * attribute [symmetric] now works for relations as well; it turns
  2420 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2421 
  2422 * induct over a !!-quantified statement (say !!x1..xn):
  2423   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2424 
  2425 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2426 %x. None. Warning: empty_def now refers to the previously hidden definition
  2427 of the empty set.
  2428 
  2429 * Algebra: formalization of classical algebra.  Intended as base for
  2430 any algebraic development in Isabelle.  Currently covers group theory
  2431 (up to Sylow's theorem) and ring theory (Universal Property of
  2432 Univariate Polynomials).  Contributions welcome;
  2433 
  2434 * GroupTheory: deleted, since its material has been moved to Algebra;
  2435 
  2436 * Complex: new directory of the complex numbers with numeric constants,
  2437 nonstandard complex numbers, and some complex analysis, standard and
  2438 nonstandard (Jacques Fleuriot);
  2439 
  2440 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2441 
  2442 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2443 Fleuriot);
  2444 
  2445 * Real/HahnBanach: updated and adapted to locales;
  2446 
  2447 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2448 Gray and Kramer);
  2449 
  2450 * UNITY: added the Meier-Sanders theory of progress sets;
  2451 
  2452 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2453 as abstract algorithms, instantiated to the JVM;
  2454 
  2455 * Bali: Java source language formalization. Type system, operational
  2456 semantics, axiomatic semantics. Supported language features:
  2457 classes, interfaces, objects,virtual methods, static methods,
  2458 static/instance fields, arrays, access modifiers, definite
  2459 assignment, exceptions.
  2460 
  2461 
  2462 *** ZF ***
  2463 
  2464 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2465 universe, etc.);
  2466 
  2467 * Main ZF: virtually all theories converted to new-style format;
  2468 
  2469 
  2470 *** ML ***
  2471 
  2472 * Pure: Tactic.prove provides sane interface for internal proofs;
  2473 omits the infamous "standard" operation, so this is more appropriate
  2474 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2475 
  2476 * Pure: improved error reporting of simprocs;
  2477 
  2478 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2479 up simprocs;
  2480 
  2481 
  2482 *** Document preparation ***
  2483 
  2484 * uses \par instead of \\ for line breaks in theory text. This may
  2485 shift some page breaks in large documents. To get the old behaviour
  2486 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2487 
  2488 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2489 other packages
  2490 
  2491 * \<euro> now needs package babel/greek instead of marvosym (which
  2492 broke \Rightarrow)
  2493 
  2494 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2495 textcomp package)
  2496 
  2497 
  2498 
  2499 New in Isabelle2002 (March 2002)
  2500 --------------------------------
  2501 
  2502 *** Document preparation ***
  2503 
  2504 * greatly simplified document preparation setup, including more
  2505 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2506 instructive isatool mkdir; users should basically be able to get
  2507 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2508 users may run a separate document processing stage manually like this:
  2509 "isatool usedir -D output HOL Test && isatool document Test/output";
  2510 
  2511 * theory dependency graph may now be incorporated into documents;
  2512 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2513 with \includegraphics of LaTeX;
  2514 
  2515 * proper spacing of consecutive markup elements, especially text
  2516 blocks after section headings;
  2517 
  2518 * support bold style (for single symbols only), input syntax is like
  2519 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2520 
  2521 * \<bullet> is now output as bold \cdot by default, which looks much
  2522 better in printed text;
  2523 
  2524 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2525 note that these symbols are currently unavailable in Proof General /
  2526 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2527 
  2528 * isatool latex no longer depends on changed TEXINPUTS, instead
  2529 isatool document copies the Isabelle style files to the target
  2530 location;
  2531 
  2532 
  2533 *** Isar ***
  2534 
  2535 * Pure/Provers: improved proof by cases and induction;
  2536   - 'case' command admits impromptu naming of parameters (such as
  2537     "case (Suc n)");
  2538   - 'induct' method divinates rule instantiation from the inductive
  2539     claim; no longer requires excessive ?P bindings for proper
  2540     instantiation of cases;
  2541   - 'induct' method properly enumerates all possibilities of set/type
  2542     rules; as a consequence facts may be also passed through *type*
  2543     rules without further ado;
  2544   - 'induct' method now derives symbolic cases from the *rulified*
  2545     rule (before it used to rulify cases stemming from the internal
  2546     atomized version); this means that the context of a non-atomic
  2547     statement becomes is included in the hypothesis, avoiding the
  2548     slightly cumbersome show "PROP ?case" form;
  2549   - 'induct' may now use elim-style induction rules without chaining
  2550     facts, using ``missing'' premises from the goal state; this allows
  2551     rules stemming from inductive sets to be applied in unstructured
  2552     scripts, while still benefitting from proper handling of non-atomic
  2553     statements; NB: major inductive premises need to be put first, all
  2554     the rest of the goal is passed through the induction;
  2555   - 'induct' proper support for mutual induction involving non-atomic
  2556     rule statements (uses the new concept of simultaneous goals, see
  2557     below);
  2558   - append all possible rule selections, but only use the first
  2559     success (no backtracking);
  2560   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2561   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2562   - added 'print_induct_rules' (covered by help item in recent Proof
  2563     General versions);
  2564   - moved induct/cases attributes to Pure, methods to Provers;
  2565   - generic method setup instantiated for FOL and HOL;
  2566 
  2567 * Pure: support multiple simultaneous goal statements, for example
  2568 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2569 meta-level mechanism, this acts as if several individual goals had
  2570 been stated separately; in particular common proof methods need to be
  2571 repeated in order to cover all claims; note that a single elimination
  2572 step is *not* sufficient to establish the two conjunctions, so this
  2573 fails:
  2574 
  2575   assume "A & B" then have A and B ..   (*".." fails*)
  2576 
  2577 better use "obtain" in situations as above; alternative refer to
  2578 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2579 
  2580 * Pure: proper integration with ``locales''; unlike the original
  2581 version by Florian Kammller, Isar locales package high-level proof
  2582 contexts rather than raw logical ones (e.g. we admit to include
  2583 attributes everywhere); operations on locales include merge and
  2584 rename; support for implicit arguments (``structures''); simultaneous
  2585 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2586 some examples;
  2587 
  2588 * Pure: the following commands have been ``localized'', supporting a
  2589 target locale specification "(in name)": 'lemma', 'theorem',
  2590 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2591 stored both within the locale and at the theory level (exported and
  2592 qualified by the locale name);
  2593 
  2594 * Pure: theory goals may now be specified in ``long'' form, with
  2595 ad-hoc contexts consisting of arbitrary locale elements. for example
  2596 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2597 definitions may be given, too); the result is a meta-level rule with
  2598 the context elements being discharged in the obvious way;
  2599 
  2600 * Pure: new proof command 'using' allows to augment currently used
  2601 facts after a goal statement ('using' is syntactically analogous to
  2602 'apply', but acts on the goal's facts only); this allows chained facts
  2603 to be separated into parts given before and after a claim, as in
  2604 ``from a and b have C using d and e <proof>'';
  2605 
  2606 * Pure: renamed "antecedent" case to "rule_context";
  2607 
  2608 * Pure: new 'judgment' command records explicit information about the
  2609 object-logic embedding (used by several tools internally); no longer
  2610 use hard-wired "Trueprop";
  2611 
  2612 * Pure: added 'corollary' command;
  2613 
  2614 * Pure: fixed 'token_translation' command;
  2615 
  2616 * Pure: removed obsolete 'exported' attribute;
  2617 
  2618 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2619 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2620 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2621 
  2622 * Pure: method 'atomize' presents local goal premises as object-level
  2623 statements (atomic meta-level propositions); setup controlled via
  2624 rewrite rules declarations of 'atomize' attribute; example
  2625 application: 'induct' method with proper rule statements in improper
  2626 proof *scripts*;
  2627 
  2628 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2629 now consider the syntactic context of assumptions, giving a better
  2630 chance to get type-inference of the arguments right (this is
  2631 especially important for locales);
  2632 
  2633 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2634 mode;
  2635 
  2636 * Pure/obtain: the formal conclusion "thesis", being marked as
  2637 ``internal'', may no longer be reference directly in the text;
  2638 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2639 situations;
  2640 
  2641 * Pure: generic 'sym' attribute which declares a rule both as pure
  2642 'elim?' and for the 'symmetric' operation;
  2643 
  2644 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2645 text; the fixed correlation with particular command syntax has been
  2646 discontinued;
  2647 
  2648 * Pure: new method 'rules' is particularly well-suited for proof
  2649 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2650 but often produces more compact proof terms with less detours;
  2651 
  2652 * Pure/Provers/classical: simplified integration with pure rule
  2653 attributes and methods; the classical "intro?/elim?/dest?"
  2654 declarations coincide with the pure ones; the "rule" method no longer
  2655 includes classically swapped intros; "intro" and "elim" methods no
  2656 longer pick rules from the context; also got rid of ML declarations
  2657 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2658 INCOMPATIBILITY;
  2659 
  2660 * Provers/classical: attribute 'swapped' produces classical inversions
  2661 of introduction rules;
  2662 
  2663 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2664 rules instead of full simplifier context; 'iff' attribute handles
  2665 conditional rules;
  2666 
  2667 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2668 
  2669 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2670 "(permissive)" option to recover old behavior;
  2671 
  2672 * HOL: 'inductive' no longer features separate (collective) attributes
  2673 for 'intros' (was found too confusing);
  2674 
  2675 * HOL: properly declared induction rules less_induct and
  2676 wf_induct_rule;
  2677 
  2678 
  2679 *** HOL ***
  2680 
  2681 * HOL: moved over to sane numeral syntax; the new policy is as
  2682 follows:
  2683 
  2684   - 0 and 1 are polymorphic constants, which are defined on any
  2685   numeric type (nat, int, real etc.);
  2686 
  2687   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2688   binary representation internally;
  2689 
  2690   - type nat has special constructor Suc, and generally prefers Suc 0
  2691   over 1::nat and Suc (Suc 0) over 2::nat;
  2692 
  2693 This change may cause significant problems of INCOMPATIBILITY; here
  2694 are some hints on converting existing sources:
  2695 
  2696   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2697   entities, so expressions involving "-" (unary or binary minus) need
  2698   to be spaced properly;
  2699 
  2700   - existing occurrences of "1" may need to be constraint "1::nat" or
  2701   even replaced by Suc 0; similar for old "2";
  2702 
  2703   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2704 
  2705   - remove all special provisions on numerals in proofs;
  2706 
  2707 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2708 representation (depends on bin_arith_simps in the default context);
  2709 
  2710 * HOL: symbolic syntax for x^2 (numeral 2);
  2711 
  2712 * HOL: the class of all HOL types is now called "type" rather than
  2713 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2714 in axclass/classes, instance/arities, and (usually rare) occurrences
  2715 in typings (of consts etc.); internally the class is called
  2716 "HOL.type", ML programs should refer to HOLogic.typeS;
  2717 
  2718 * HOL/record package improvements:
  2719   - new derived operations "fields" to build a partial record section,
  2720     "extend" to promote a fixed record to a record scheme, and
  2721     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2722     declared as simp by default;
  2723   - shared operations ("more", "fields", etc.) now need to be always
  2724     qualified) --- potential INCOMPATIBILITY;
  2725   - removed "make_scheme" operations (use "make" with "extend") --
  2726     INCOMPATIBILITY;
  2727   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2728   - provides cases/induct rules for use with corresponding Isar
  2729     methods (for concrete records, record schemes, concrete more
  2730     parts, and schematic more parts -- in that order);
  2731   - internal definitions directly based on a light-weight abstract
  2732     theory of product types over typedef rather than datatype;
  2733 
  2734 * HOL: generic code generator for generating executable ML code from
  2735 specifications; specific support for HOL constructs such as inductive
  2736 datatypes and sets, as well as recursive functions; can be invoked
  2737 via 'generate_code' theory section;
  2738 
  2739 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2740 
  2741 * HOL: consolidated and renamed several theories.  In particular:
  2742         Ord.thy has been absorbed into HOL.thy
  2743         String.thy has been absorbed into List.thy
  2744 
  2745 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2746 (beware of argument permutation!);
  2747 
  2748 * HOL: linorder_less_split superseded by linorder_cases;
  2749 
  2750 * HOL/List: "nodups" renamed to "distinct";
  2751 
  2752 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2753 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2754   - Ex_def has changed, now need to use some_eq_ex
  2755 
  2756 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2757 in this (rare) case use:
  2758 
  2759   delSWrapper "split_all_tac"
  2760   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2761 
  2762 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2763 MAY FAIL;
  2764 
  2765 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2766 Isabelle's type classes, ^ on functions and relations has too general
  2767 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2768 necessary to attach explicit type constraints;
  2769 
  2770 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2771 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2772 renamed accordingly (eg "compI" -> "rel_compI").
  2773 
  2774 * HOL: syntax translations now work properly with numerals and records
  2775 expressions;
  2776 
  2777 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2778 of "lam" -- INCOMPATIBILITY;
  2779 
  2780 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2781 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2782 renamed "Product_Type.unit";
  2783 
  2784 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2785 
  2786 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2787 the "cases" method);
  2788 
  2789 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2790 Florian Kammller);
  2791 
  2792 * HOL/IMP: updated and converted to new-style theory format; several
  2793 parts turned into readable document, with proper Isar proof texts and
  2794 some explanations (by Gerwin Klein);
  2795 
  2796 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2797 
  2798 * HOL-Hyperreal is now a logic image;
  2799 
  2800 
  2801 *** HOLCF ***
  2802 
  2803 * Isar: consts/constdefs supports mixfix syntax for continuous
  2804 operations;
  2805 
  2806 * Isar: domain package adapted to new-style theory format, e.g. see
  2807 HOLCF/ex/Dnat.thy;
  2808 
  2809 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2810 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2811 lift.induct_tac, always use UU instead of Undef;
  2812 
  2813 * HOLCF/IMP: updated and converted to new-style theory;
  2814 
  2815 
  2816 *** ZF ***
  2817 
  2818 * Isar: proper integration of logic-specific tools and packages,
  2819 including theory commands '(co)inductive', '(co)datatype',
  2820 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2821 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2822 
  2823 * theory Main no longer includes AC; for the Axiom of Choice, base
  2824 your theory on Main_ZFC;
  2825 
  2826 * the integer library now covers quotients and remainders, with many
  2827 laws relating division to addition, multiplication, etc.;
  2828 
  2829 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2830 typeless version of the formalism;
  2831 
  2832 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2833 format;
  2834 
  2835 * ZF/Induct: new directory for examples of inductive definitions,
  2836 including theory Multiset for multiset orderings; converted to
  2837 new-style theory format;
  2838 
  2839 * ZF: many new theorems about lists, ordinals, etc.;
  2840 
  2841 
  2842 *** General ***
  2843 
  2844 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2845 variable proof controls level of detail: 0 = no proofs (only oracle
  2846 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2847 also ref manual for further ML interfaces;
  2848 
  2849 * Pure/axclass: removed obsolete ML interface
  2850 goal_subclass/goal_arity;
  2851 
  2852 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2853 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2854 separate tokens, so expressions involving minus need to be spaced
  2855 properly;
  2856 
  2857 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2858 rather than "infixl" or "infixr";
  2859 
  2860 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2861 sort constraint specifications in type inference; e.g. "x::_::foo"
  2862 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2863 type variable);
  2864 
  2865 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2866 control output of nested => (types); the default behavior is
  2867 "type_brackets";
  2868 
  2869 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2870 tokens into AST constants;
  2871 
  2872 * Pure/syntax: prefer later declarations of translations and print
  2873 translation functions; potential INCOMPATIBILITY: need to reverse
  2874 multiple declarations for same syntax element constant;
  2875 
  2876 * Pure/show_hyps reset by default (in accordance to existing Isar
  2877 practice);
  2878 
  2879 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2880 addSafter;
  2881 
  2882 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2883 as well;
  2884 
  2885 * system: tested support for MacOS X; should be able to get Isabelle +
  2886 Proof General to work in a plain Terminal after installing Poly/ML
  2887 (e.g. from the Isabelle distribution area) and GNU bash alone
  2888 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2889 support requires further installations, e.g. from
  2890 http://fink.sourceforge.net/);
  2891 
  2892 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2893 
  2894 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2895 of 40 MB), cf. ML_OPTIONS;
  2896 
  2897 * system: Proof General keywords specification is now part of the
  2898 Isabelle distribution (see etc/isar-keywords.el);
  2899 
  2900 * system: support for persistent Proof General sessions (refrain from
  2901 outdating all loaded theories on startup); user may create writable
  2902 logic images like this: ``isabelle -q HOL Test'';
  2903 
  2904 * system: smart selection of Isabelle process versus Isabelle
  2905 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2906 run both "isabelle" and "Isabelle" even if file names are badly
  2907 damaged (executable inspects the case of the first letter of its own
  2908 name); added separate "isabelle-process" and "isabelle-interface";
  2909 
  2910 * system: refrain from any attempt at filtering input streams; no
  2911 longer support ``8bit'' encoding of old isabelle font, instead proper
  2912 iso-latin characters may now be used; the related isatools
  2913 "symbolinput" and "nonascii" have disappeared as well;
  2914 
  2915 * system: removed old "xterm" interface (the print modes "xterm" and
  2916 "xterm_color" are still available for direct use in a suitable
  2917 terminal);
  2918 
  2919 
  2920 
  2921 New in Isabelle99-2 (February 2001)
  2922 -----------------------------------
  2923 
  2924 *** Overview of INCOMPATIBILITIES ***
  2925 
  2926 * HOL: please note that theories in the Library and elsewhere often use the
  2927 new-style (Isar) format; to refer to their theorems in an ML script you must
  2928 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2929 
  2930 * HOL: inductive package no longer splits induction rule aggressively,
  2931 but only as far as specified by the introductions given; the old
  2932 format may be recovered via ML function complete_split_rule or attribute
  2933 'split_rule (complete)';
  2934 
  2935 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2936 gfp_Tarski to gfp_unfold;
  2937 
  2938 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2939 
  2940 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2941 relation); infix "^^" has been renamed "``"; infix "``" has been
  2942 renamed "`"; "univalent" has been renamed "single_valued";
  2943 
  2944 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2945 operation;
  2946 
  2947 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2948 
  2949 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2950 
  2951 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2952 consequence, it is no longer monotonic wrt. the local goal context
  2953 (which is now passed through the inductive cases);
  2954 
  2955 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2956 \<gg> to \<ggreater>;
  2957 
  2958 
  2959 *** Document preparation ***
  2960 
  2961 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2962 available: are "it" for near math-mode best-style output, "sl" for
  2963 slanted text style, and "tt" for plain type-writer; if no
  2964 \isabellestyle command is given, output is according to slanted
  2965 type-writer);
  2966 
  2967 * support sub/super scripts (for single symbols only), input syntax is
  2968 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2969 
  2970 * some more standard symbols; see Appendix A of the system manual for
  2971 the complete list of symbols defined in isabellesym.sty;
  2972 
  2973 * improved isabelle style files; more abstract symbol implementation
  2974 (should now use \isamath{...} and \isatext{...} in custom symbol
  2975 definitions);
  2976 
  2977 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2978 state; Note that presentation of goal states does not conform to
  2979 actual human-readable proof documents.  Please do not include goal
  2980 states into document output unless you really know what you are doing!
  2981 
  2982 * proper indentation of antiquoted output with proportional LaTeX
  2983 fonts;
  2984 
  2985 * no_document ML operator temporarily disables LaTeX document
  2986 generation;
  2987 
  2988 * isatool unsymbolize tunes sources for plain ASCII communication;
  2989 
  2990 
  2991 *** Isar ***
  2992 
  2993 * Pure: Isar now suffers initial goal statements to contain unbound
  2994 schematic variables (this does not conform to actual readable proof
  2995 documents, due to unpredictable outcome and non-compositional proof
  2996 checking); users who know what they are doing may use schematic goals
  2997 for Prolog-style synthesis of proven results;
  2998 
  2999 * Pure: assumption method (an implicit finishing) now handles actual
  3000 rules as well;
  3001 
  3002 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3003 initial goal, declare "that" only as Pure intro (only for single
  3004 steps); the "that" rule assumption may now be involved in implicit
  3005 finishing, thus ".." becomes a feasible for trivial obtains;
  3006 
  3007 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3008 instance proofs may be performed by "..";
  3009 
  3010 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3011 statements as well;
  3012 
  3013 * Pure: more robust selection of calculational rules;
  3014 
  3015 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3016 rule (as well as the assumption rule);
  3017 
  3018 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3019 lemmas, using the graph browser tool;
  3020 
  3021 * Pure: predict failure of "show" in interactive mode;
  3022 
  3023 * Pure: 'thms_containing' now takes actual terms as arguments;
  3024 
  3025 * HOL: improved method 'induct' --- now handles non-atomic goals
  3026 (potential INCOMPATIBILITY); tuned error handling;
  3027 
  3028 * HOL: cases and induct rules now provide explicit hints about the
  3029 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3030 any remaining facts are inserted into the goal verbatim;
  3031 
  3032 * HOL: local contexts (aka cases) may now contain term bindings as
  3033 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3034 the result to be shown in each case;
  3035 
  3036 * HOL: added 'recdef_tc' command;
  3037 
  3038 * isatool convert assists in eliminating legacy ML scripts;
  3039 
  3040 
  3041 *** HOL ***
  3042 
  3043 * HOL/Library: a collection of generic theories to be used together
  3044 with main HOL; the theory loader path already includes this directory
  3045 by default; the following existing theories have been moved here:
  3046 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3047 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3048 
  3049 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3050 modelling and verification task performed in Isabelle/HOL +
  3051 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3052 
  3053 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3054 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3055 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3056 'domain', this makes the theory consistent with mathematical
  3057 literature;
  3058 
  3059 * HOL basics: added overloaded operations "inverse" and "divide"
  3060 (infix "/"), syntax for generic "abs" operation, generic summation
  3061 operator \<Sum>;
  3062 
  3063 * HOL/typedef: simplified package, provide more useful rules (see also
  3064 HOL/subset.thy);
  3065 
  3066 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3067 now expressed as a proper nested rule (old-style tactic scripts may
  3068 require atomize_strip_tac to cope with non-atomic premises);
  3069 
  3070 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3071 to "split_conv" (old name still available for compatibility);
  3072 
  3073 * HOL: improved concrete syntax for strings (e.g. allows translation
  3074 rules with string literals);
  3075 
  3076 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3077  and Fleuriot's mechanization of analysis, including the transcendental
  3078  functions for the reals;
  3079 
  3080 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3081 
  3082 
  3083 *** CTT ***
  3084 
  3085 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3086 "lam" is displayed as TWO lambda-symbols
  3087 
  3088 * CTT: theory Main now available, containing everything (that is, Bool
  3089 and Arith);
  3090 
  3091 
  3092 *** General ***
  3093 
  3094 * Pure: the Simplifier has been implemented properly as a derived rule
  3095 outside of the actual kernel (at last!); the overall performance
  3096 penalty in practical applications is about 50%, while reliability of
  3097 the Isabelle inference kernel has been greatly improved;
  3098 
  3099 * print modes "brackets" and "no_brackets" control output of nested =>
  3100 (types) and ==> (props); the default behaviour is "brackets";
  3101 
  3102 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3103 as assumptions as well;
  3104 
  3105 * system: support Poly/ML 4.0;
  3106 
  3107 * system: isatool install handles KDE version 1 or 2;
  3108 
  3109 
  3110 
  3111 New in Isabelle99-1 (October 2000)
  3112 ----------------------------------
  3113 
  3114 *** Overview of INCOMPATIBILITIES ***
  3115 
  3116 * HOL: simplification of natural numbers is much changed; to partly
  3117 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3118 issue the following ML commands:
  3119 
  3120   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3121   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3122 
  3123 * HOL: simplification no longer dives into case-expressions; this is
  3124 controlled by "t.weak_case_cong" for each datatype t;
  3125 
  3126 * HOL: nat_less_induct renamed to less_induct;
  3127 
  3128 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3129 fixsome to patch .thy and .ML sources automatically;
  3130 
  3131   select_equality  -> some_equality
  3132   select_eq_Ex     -> some_eq_ex
  3133   selectI2EX       -> someI2_ex
  3134   selectI2         -> someI2
  3135   selectI          -> someI
  3136   select1_equality -> some1_equality
  3137   Eps_sym_eq       -> some_sym_eq_trivial
  3138   Eps_eq           -> some_eq_trivial
  3139 
  3140 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3141 
  3142 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3143 instead);
  3144 
  3145 * HOL: the recursion equations generated by 'recdef' are now called
  3146 f.simps instead of f.rules;
  3147 
  3148 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3149 
  3150 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3151 sometimes be needed;
  3152 
  3153 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3154 
  3155 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3156 
  3157 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3158 product is now "<*>" instead of "Times"; the lexicographic product is
  3159 now "<*lex*>" instead of "**";
  3160 
  3161 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3162 of main HOL, but was unused); better use HOL's datatype package;
  3163 
  3164 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3165 the old syntax may be recovered as follows:
  3166 
  3167   syntax (symbols)
  3168     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3169       (infixl "\\<oplus>" 100)
  3170 
  3171 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3172 
  3173 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3174 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3175 internally;
  3176 
  3177 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3178 changed from A/r to A//r;
  3179 
  3180 * ZF: new treatment of arithmetic (nat & int) may break some old
  3181 proofs;
  3182 
  3183 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3184 rulify -> rule_format, elimify -> elim_format, ...);
  3185 
  3186 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3187 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3188 should have to change intro!! to intro? only); replaced "delrule" by
  3189 "rule del";
  3190 
  3191 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3192 
  3193 * Provers: strengthened force_tac by using new first_best_tac;
  3194 
  3195 * LaTeX document preparation: several changes of isabelle.sty (see
  3196 lib/texinputs);
  3197 
  3198 
  3199 *** Document preparation ***
  3200 
  3201 * formal comments (text blocks etc.) in new-style theories may now
  3202 contain antiquotations of thm/prop/term/typ/text to be presented
  3203 according to latex print mode; concrete syntax is like this:
  3204 @{term[show_types] "f(x) = a + x"};
  3205 
  3206 * isatool mkdir provides easy setup of Isabelle session directories,
  3207 including proper document sources;
  3208 
  3209 * generated LaTeX sources are now deleted after successful run
  3210 (isatool document -c); may retain a copy somewhere else via -D option
  3211 of isatool usedir;
  3212 
  3213 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3214 style files, achieving self-contained LaTeX sources and simplifying
  3215 LaTeX debugging;
  3216 
  3217 * old-style theories now produce (crude) LaTeX output as well;
  3218 
  3219 * browser info session directories are now self-contained (may be put
  3220 on WWW server seperately); improved graphs of nested sessions; removed
  3221 graph for 'all sessions';
  3222 
  3223 * several improvements in isabelle style files; \isabellestyle{it}
  3224 produces fake math mode output; \isamarkupheader is now \section by
  3225 default; see lib/texinputs/isabelle.sty etc.;
  3226 
  3227 
  3228 *** Isar ***
  3229 
  3230 * Isar/Pure: local results and corresponding term bindings are now
  3231 subject to Hindley-Milner polymorphism (similar to ML); this
  3232 accommodates incremental type-inference very nicely;
  3233 
  3234 * Isar/Pure: new derived language element 'obtain' supports
  3235 generalized existence reasoning;
  3236 
  3237 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3238 support accumulation of results, without applying any rules yet;
  3239 useful to collect intermediate results without explicit name
  3240 references, and for use with transitivity rules with more than 2
  3241 premises;
  3242 
  3243 * Isar/Pure: scalable support for case-analysis type proofs: new
  3244 'case' language element refers to local contexts symbolically, as
  3245 produced by certain proof methods; internally, case names are attached
  3246 to theorems as "tags";
  3247 
  3248 * Isar/Pure: theory command 'hide' removes declarations from
  3249 class/type/const name spaces;
  3250 
  3251 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3252 indicate potential overloading;
  3253 
  3254 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3255 
  3256 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3257 "{a,b,c}" instead of {a,b,c};
  3258 
  3259 * Isar/Pure now provides its own version of intro/elim/dest
  3260 attributes; useful for building new logics, but beware of confusion
  3261 with the version in Provers/classical;
  3262 
  3263 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3264 case name 'antecedent';
  3265 
  3266 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3267 to the current context is now done automatically);
  3268 
  3269 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3270 for definining proof methods in ML;
  3271 
  3272 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3273 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3274 most cases, one should have to change intro!! to intro? only);
  3275 replaced "delrule" by "rule del";
  3276 
  3277 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3278 'symmetric' attribute (the latter supercedes [RS sym]);
  3279 
  3280 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3281 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3282 well (including splits);
  3283 
  3284 * Isar/Provers: Simplifier and Classical methods now support all kind
  3285 of modifiers used in the past, including 'cong', 'iff', etc.
  3286 
  3287 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3288 of Simplifier and Classical reasoner);
  3289 
  3290 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3291 now support named cases; major packages (inductive, datatype, primrec,
  3292 recdef) support case names and properly name parameters;
  3293 
  3294 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3295 monotonicity conditions are extracted to be proven at end of
  3296 calculations;
  3297 
  3298 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3299 method anyway;
  3300 
  3301 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3302 split_if split_if_asm; datatype package provides theorems foo.splits =
  3303 foo.split foo.split_asm for each datatype;
  3304 
  3305 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3306 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3307 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3308 use "(cases (simplified))" method in proper proof texts);
  3309 
  3310 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3311 
  3312 * Isar: names of theorems etc. may be natural numbers as well;
  3313 
  3314 * Isar: 'pr' command: optional arguments for goals_limit and
  3315 ProofContext.prems_limit; no longer prints theory contexts, but only
  3316 proof states;
  3317 
  3318 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3319 additional print modes to be specified; e.g. "pr(latex)" will print
  3320 proof state according to the Isabelle LaTeX style;
  3321 
  3322 * Isar: improved support for emulating tactic scripts, including proof
  3323 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3324 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3325 (for HOL datatypes);
  3326 
  3327 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3328 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3329 'proof method scripts' have to be in depth-first order;
  3330 
  3331 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3332 
  3333 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3334 should instead use individual commands for printing items
  3335 (print_commands, print_methods etc.);
  3336 
  3337 * Isar: added 'nothing' --- the empty list of theorems;
  3338 
  3339 
  3340 *** HOL ***
  3341 
  3342 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3343 corresponding virtual machine and a specification of its bytecode
  3344 verifier and a lightweight bytecode verifier, including proofs of
  3345 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3346 Cornelia Pusch (see also the homepage of project Bali at
  3347 http://isabelle.in.tum.de/Bali/);
  3348 
  3349 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3350 Clemens Ballarin;
  3351 
  3352 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3353 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3354 Rasmussen;
  3355 
  3356 * HOL/Lattice: fundamental concepts of lattice theory and order
  3357 structures, including duals, properties of bounds versus algebraic
  3358 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3359 Theorem for complete lattices etc.; may also serve as a demonstration
  3360 for abstract algebraic reasoning using axiomatic type classes, and
  3361 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3362 
  3363 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3364 von Oheimb;
  3365 
  3366 * HOL/IMPP: extension of IMP with local variables and mutually
  3367 recursive procedures, by David von Oheimb;
  3368 
  3369 * HOL/Lambda: converted into new-style theory and document;
  3370 
  3371 * HOL/ex/Multiquote: example of multiple nested quotations and
  3372 anti-quotations -- basically a generalized version of de-Bruijn
  3373 representation; very useful in avoiding lifting of operations;
  3374 
  3375 * HOL/record: added general record equality rule to simpset; fixed
  3376 select-update simplification procedure to handle extended records as
  3377 well; admit "r" as field name;
  3378 
  3379 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3380 other numeric types and also as the identity of groups, rings, etc.;
  3381 
  3382 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3383 Types nat and int belong to this axclass;
  3384 
  3385 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3386    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3387    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3388   two terms #m*u and #n*u are replaced by #(m+n)*u
  3389     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3390   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3391     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3392 
  3393 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3394 powerful prover for predicate logic but knows nothing of clasets; see
  3395 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3396 
  3397 * HOL: new version of "case_tac" subsumes both boolean case split and
  3398 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3399 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3400 
  3401 * HOL: simplification no longer dives into case-expressions: only the
  3402 selector expression is simplified, but not the remaining arms; to
  3403 enable full simplification of case-expressions for datatype t, you may
  3404 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3405 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3406 
  3407 * HOL/recdef: the recursion equations generated by 'recdef' for
  3408 function 'f' are now called f.simps instead of f.rules; if all
  3409 termination conditions are proved automatically, these simplification
  3410 rules are added to the simpset, as in primrec; rules may be named
  3411 individually as well, resulting in a separate list of theorems for
  3412 each equation;
  3413 
  3414 * HOL/While is a new theory that provides a while-combinator. It
  3415 permits the definition of tail-recursive functions without the
  3416 provision of a termination measure. The latter is necessary once the
  3417 invariant proof rule for while is applied.
  3418 
  3419 * HOL: new (overloaded) notation for the set of elements below/above
  3420 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3421 
  3422 * HOL: theorems impI, allI, ballI bound as "strip";
  3423 
  3424 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3425 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3426 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3427 
  3428 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3429 
  3430 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3431 main HOL, but was unused);
  3432 
  3433 * HOL: fewer consts declared as global (e.g. have to refer to
  3434 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3435 
  3436 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3437 in case of overlap with user translations (e.g. judgements over
  3438 tuples); (note that the underlying logical represenation is still
  3439 bogus);
  3440 
  3441 
  3442 *** ZF ***
  3443 
  3444 * ZF: simplification automatically cancels common terms in arithmetic
  3445 expressions over nat and int;
  3446 
  3447 * ZF: new treatment of nat to minimize type-checking: all operators
  3448 coerce their operands to a natural number using the function natify,
  3449 making the algebraic laws unconditional;
  3450 
  3451 * ZF: as above, for int: operators coerce their operands to an integer
  3452 using the function intify;
  3453 
  3454 * ZF: the integer library now contains many of the usual laws for the
  3455 orderings, including $<=, and monotonicity laws for $+ and $*;
  3456 
  3457 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3458 simplification;
  3459 
  3460 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3461 to the simplifier and classical reasoner simultaneously;
  3462 
  3463 
  3464 *** General ***
  3465 
  3466 * Provers: blast_tac now handles actual object-logic rules as
  3467 assumptions; note that auto_tac uses blast_tac internally as well;
  3468 
  3469 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3470 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3471 
  3472 * Provers: delrules now handles destruct rules as well (no longer need
  3473 explicit make_elim);
  3474 
  3475 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3476   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3477 use instead the strong form,
  3478   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3479 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3480 from destruct-rules;
  3481 
  3482 * Provers: Simplifier.easy_setup provides a fast path to basic
  3483 Simplifier setup for new object-logics;
  3484 
  3485 * Pure: AST translation rules no longer require constant head on LHS;
  3486 
  3487 * Pure: improved name spaces: ambiguous output is qualified; support
  3488 for hiding of names;
  3489 
  3490 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3491 XSYMBOL_HOME; no longer need to do manual configuration in most
  3492 situations;
  3493 
  3494 * system: compression of ML heaps images may now be controlled via -c
  3495 option of isabelle and isatool usedir (currently only observed by
  3496 Poly/ML);
  3497 
  3498 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3499 useful for remote X11);
  3500 
  3501 * system: provide TAGS file for Isabelle sources;
  3502 
  3503 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3504 order;
  3505 
  3506 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3507 timing flag supersedes proof_timing and Toplevel.trace;
  3508 
  3509 * ML: new combinators |>> and |>>> for incremental transformations
  3510 with secondary results (e.g. certain theory extensions):
  3511 
  3512 * ML: PureThy.add_defs gets additional argument to indicate potential
  3513 overloading (usually false);
  3514 
  3515 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3516 results;
  3517 
  3518 
  3519 
  3520 New in Isabelle99 (October 1999)
  3521 --------------------------------
  3522 
  3523 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3524 
  3525 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3526 are no longer simplified.  (This allows the simplifier to unfold recursive
  3527 functional programs.)  To restore the old behaviour, declare
  3528 
  3529     Delcongs [if_weak_cong];
  3530 
  3531 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3532 complement;
  3533 
  3534 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3535 
  3536 * HOL/datatype: mutual_induct_tac no longer exists --
  3537   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3538 
  3539 * HOL/typedef: fixed type inference for representing set; type
  3540 arguments now have to occur explicitly on the rhs as type constraints;
  3541 
  3542 * ZF: The con_defs part of an inductive definition may no longer refer
  3543 to constants declared in the same theory;
  3544 
  3545 * HOL, ZF: the function mk_cases, generated by the inductive
  3546 definition package, has lost an argument.  To simplify its result, it
  3547 uses the default simpset instead of a supplied list of theorems.
  3548 
  3549 * HOL/List: the constructors of type list are now Nil and Cons;
  3550 
  3551 * Simplifier: the type of the infix ML functions
  3552         setSSolver addSSolver setSolver addSolver
  3553 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3554 for packaging solvers. A solver is created via
  3555         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3556 where the string argument is only a comment.
  3557 
  3558 
  3559 *** Proof tools ***
  3560 
  3561 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3562 decision procedure for linear arithmetic. Currently it is used for
  3563 types `nat', `int', and `real' in HOL (see below); it can, should and
  3564 will be instantiated for other types and logics as well.
  3565 
  3566 * The simplifier now accepts rewrite rules with flexible heads, eg
  3567      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3568   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3569   matching.
  3570 
  3571 
  3572 *** General ***
  3573 
  3574 * New Isabelle/Isar subsystem provides an alternative to traditional
  3575 tactical theorem proving; together with the ProofGeneral/isar user
  3576 interface it offers an interactive environment for developing human
  3577 readable proof documents (Isar == Intelligible semi-automated
  3578 reasoning); for further information see isatool doc isar-ref,
  3579 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3580 
  3581 * improved and simplified presentation of theories: better HTML markup
  3582 (including colors), graph views in several sizes; isatool usedir now
  3583 provides a proper interface for user theories (via -P option); actual
  3584 document preparation based on (PDF)LaTeX is available as well (for
  3585 new-style theories only); see isatool doc system for more information;
  3586 
  3587 * native support for Proof General, both for classic Isabelle and
  3588 Isabelle/Isar;
  3589 
  3590 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3591 using the graph browser tool;
  3592 
  3593 * Isabelle manuals now also available as PDF;
  3594 
  3595 * theory loader rewritten from scratch (may not be fully
  3596 bug-compatible); old loadpath variable has been replaced by show_path,
  3597 add_path, del_path, reset_path functions; new operations such as
  3598 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3599 isatool doc ref);
  3600 
  3601 * improved isatool install: option -k creates KDE application icon,
  3602 option -p DIR installs standalone binaries;
  3603 
  3604 * added ML_PLATFORM setting (useful for cross-platform installations);
  3605 more robust handling of platform specific ML images for SML/NJ;
  3606 
  3607 * the settings environment is now statically scoped, i.e. it is never
  3608 created again in sub-processes invoked from isabelle, isatool, or
  3609 Isabelle;
  3610 
  3611 * path element specification '~~' refers to '$ISABELLE_HOME';
  3612 
  3613 * in locales, the "assumes" and "defines" parts may be omitted if
  3614 empty;
  3615 
  3616 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3617 long arrows);
  3618 
  3619 * new print_mode "HTML";
  3620 
  3621 * new flag show_tags controls display of tags of theorems (which are
  3622 basically just comments that may be attached by some tools);
  3623 
  3624 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3625 mode and goal output format:
  3626 
  3627 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3628 244c244
  3629 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3630 ---
  3631 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3632 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3633 181c181
  3634 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3635 ---
  3636 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3637 
  3638 * function bind_thms stores lists of theorems (cf. bind_thm);
  3639 
  3640 * new shorthand tactics ftac, eatac, datac, fatac;
  3641 
  3642 * qed (and friends) now accept "" as result name; in that case the
  3643 theorem is not stored, but proper checks and presentation of the
  3644 result still apply;
  3645 
  3646 * theorem database now also indexes constants "Trueprop", "all",
  3647 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3648 
  3649 
  3650 *** HOL ***
  3651 
  3652 ** HOL arithmetic **
  3653 
  3654 * There are now decision procedures for linear arithmetic over nat and
  3655 int:
  3656 
  3657 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3658 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3659 are treated as atomic; subformulae not involving type `nat' or `int'
  3660 are ignored; quantified subformulae are ignored unless they are
  3661 positive universal or negative existential. The tactic has to be
  3662 invoked by hand and can be a little bit slow. In particular, the
  3663 running time is exponential in the number of occurrences of `min' and
  3664 `max', and `-' on `nat'.
  3665 
  3666 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3667 (negated) (in)equalities among the premises and the conclusion into
  3668 account (i.e. no compound formulae) and does not know about `min' and
  3669 `max', and `-' on `nat'. It is fast and is used automatically by the
  3670 simplifier.
  3671 
  3672 NB: At the moment, these decision procedures do not cope with mixed
  3673 nat/int formulae where the two parts interact, such as `m < n ==>
  3674 int(m) < int(n)'.
  3675 
  3676 * HOL/Numeral provides a generic theory of numerals (encoded
  3677 efficiently as bit strings); setup for types nat/int/real is in place;
  3678 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3679 int, existing theories and proof scripts may require a few additional
  3680 type constraints;
  3681 
  3682 * integer division and remainder can now be performed on constant
  3683 arguments;
  3684 
  3685 * many properties of integer multiplication, division and remainder
  3686 are now available;
  3687 
  3688 * An interface to the Stanford Validity Checker (SVC) is available through the
  3689 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3690 are proved automatically.  SVC must be installed separately, and its results
  3691 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3692 invocation of the underlying oracle).  For SVC see
  3693   http://verify.stanford.edu/SVC
  3694 
  3695 * IsaMakefile: the HOL-Real target now builds an actual image;
  3696 
  3697 
  3698 ** HOL misc **
  3699 
  3700 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3701 (in Isabelle/Isar) -- by Gertrud Bauer;
  3702 
  3703 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3704 analysis for assembly languages with subtypes;
  3705 
  3706 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3707 -- avoids syntactic ambiguities and treats state, transition, and
  3708 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3709 changed syntax and (many) tactics;
  3710 
  3711 * HOL/inductive: Now also handles more general introduction rules such
  3712   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3713   theorems are now maintained within the theory (maintained via the
  3714   "mono" attribute);
  3715 
  3716 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3717   (using function types) such as
  3718 
  3719   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3720 
  3721 * HOL/record: record_simproc (part of the default simpset) takes care
  3722 of selectors applied to updated records; record_split_tac is no longer
  3723 part of the default claset; update_defs may now be removed from the
  3724 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3725 
  3726   claset_ref () := claset() addSWrapper record_split_wrapper;
  3727   Delsimprocs [record_simproc]
  3728 
  3729 * HOL/typedef: fixed type inference for representing set; type
  3730 arguments now have to occur explicitly on the rhs as type constraints;
  3731 
  3732 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3733 names rather than an ML expression;
  3734 
  3735 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3736 supplied later.  Program schemes can be defined, such as
  3737     "While B C s = (if B s then While B C (C s) else s)"
  3738 where the well-founded relation can be chosen after B and C have been given.
  3739 
  3740 * HOL/List: the constructors of type list are now Nil and Cons;
  3741 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3742 course, ML tools referring to List.list.op # etc. have to be adapted;
  3743 
  3744 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3745 disabled by default; run isabelle with option -m HOL to get back to
  3746 the original Gordon/HOL-style output;
  3747 
  3748 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3749 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3750 
  3751 * HOL basic syntax simplified (more orthogonal): all variants of
  3752 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3753 Eps operator is provided as well: "SOME x. P[x]";
  3754 
  3755 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3756 
  3757 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3758 thus available for user theories;
  3759 
  3760 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3761 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3762 time;
  3763 
  3764 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3765 several times and then mp;
  3766 
  3767 
  3768 *** LK ***
  3769 
  3770 * the notation <<...>> is now available as a notation for sequences of
  3771 formulas;
  3772 
  3773 * the simplifier is now installed
  3774 
  3775 * the axiom system has been generalized (thanks to Soren Heilmann)
  3776 
  3777 * the classical reasoner now has a default rule database
  3778 
  3779 
  3780 *** ZF ***
  3781 
  3782 * new primrec section allows primitive recursive functions to be given
  3783 directly (as in HOL) over datatypes and the natural numbers;
  3784 
  3785 * new tactics induct_tac and exhaust_tac for induction (or case
  3786 analysis) over datatypes and the natural numbers;
  3787 
  3788 * the datatype declaration of type T now defines the recursor T_rec;
  3789 
  3790 * simplification automatically does freeness reasoning for datatype
  3791 constructors;
  3792 
  3793 * automatic type-inference, with AddTCs command to insert new
  3794 type-checking rules;
  3795 
  3796 * datatype introduction rules are now added as Safe Introduction rules
  3797 to the claset;
  3798 
  3799 * the syntax "if P then x else y" is now available in addition to
  3800 if(P,x,y);
  3801 
  3802 
  3803 *** Internal programming interfaces ***
  3804 
  3805 * tuned simplifier trace output; new flag debug_simp;
  3806 
  3807 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3808 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3809 
  3810 * AxClass.axclass_tac lost the theory argument;
  3811 
  3812 * tuned current_goals_markers semantics: begin / end goal avoids
  3813 printing empty lines;
  3814 
  3815 * removed prs and prs_fn hook, which was broken because it did not
  3816 include \n in its semantics, forcing writeln to add one
  3817 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3818 string -> unit if you really want to output text without newline;
  3819 
  3820 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3821 plain output, interface builders may have to enable 'isabelle_font'
  3822 mode to get Isabelle font glyphs as before;
  3823 
  3824 * refined token_translation interface; INCOMPATIBILITY: output length
  3825 now of type real instead of int;
  3826 
  3827 * theory loader actions may be traced via new ThyInfo.add_hook
  3828 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3829 your own database of information attached to *whole* theories -- as
  3830 opposed to intra-theory data slots offered via TheoryDataFun;
  3831 
  3832 * proper handling of dangling sort hypotheses (at last!);
  3833 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3834 extra sort hypotheses that can be witnessed from the type signature;
  3835 the force_strip_shyps flag is gone, any remaining shyps are simply
  3836 left in the theorem (with a warning issued by strip_shyps_warning);
  3837 
  3838 
  3839 
  3840 New in Isabelle98-1 (October 1998)
  3841 ----------------------------------
  3842 
  3843 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3844 
  3845 * several changes of automated proof tools;
  3846 
  3847 * HOL: major changes to the inductive and datatype packages, including
  3848 some minor incompatibilities of theory syntax;
  3849 
  3850 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3851 called `inj_on';
  3852 
  3853 * HOL: removed duplicate thms in Arith:
  3854   less_imp_add_less  should be replaced by  trans_less_add1
  3855   le_imp_add_le      should be replaced by  trans_le_add1
  3856 
  3857 * HOL: unary minus is now overloaded (new type constraints may be
  3858 required);
  3859 
  3860 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3861 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3862 now taken as an integer constant.
  3863 
  3864 * Pure: ML function 'theory_of' renamed to 'theory';
  3865 
  3866 
  3867 *** Proof tools ***
  3868 
  3869 * Simplifier:
  3870   1. Asm_full_simp_tac is now more aggressive.
  3871      1. It will sometimes reorient premises if that increases their power to
  3872         simplify.
  3873      2. It does no longer proceed strictly from left to right but may also
  3874         rotate premises to achieve further simplification.
  3875      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3876      old Asm_full_simp_tac in that it does not rotate premises.
  3877   2. The simplifier now knows a little bit about nat-arithmetic.
  3878 
  3879 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3880 allows for selected deletion of wrappers, by introduction of names for
  3881 wrapper functionals.  This implies that addbefore, addSbefore,
  3882 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3883 and that adding two tactics with the same name overwrites the first
  3884 one (emitting a warning).
  3885   type wrapper = (int -> tactic) -> (int -> tactic)
  3886   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3887   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3888   delWrapper, delSWrapper: claset *  string            -> claset
  3889   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3890 
  3891 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3892 semantics; addbefore now affects only the unsafe part of step_tac
  3893 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3894 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3895 by Force_tac;
  3896 
  3897 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3898 compWrapper; added safe wrapper (and access functions for it);
  3899 
  3900 * HOL/split_all_tac is now much faster and fails if there is nothing
  3901 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3902 and the names of the automatically generated variables have changed.
  3903 split_all_tac has moved within claset() from unsafe wrappers to safe
  3904 wrappers, which means that !!-bound variables are split much more
  3905 aggressively, and safe_tac and clarify_tac now split such variables.
  3906 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3907 Note: the same holds for record_split_tac, which does the job of
  3908 split_all_tac for record fields.
  3909 
  3910 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3911 permanently to the default simpset using Addsplits just like
  3912 Addsimps. They can be removed via Delsplits just like
  3913 Delsimps. Lower-case versions are also available.
  3914 
  3915 * HOL/Simplifier: The rule split_if is now part of the default
  3916 simpset. This means that the simplifier will eliminate all occurrences
  3917 of if-then-else in the conclusion of a goal. To prevent this, you can
  3918 either remove split_if completely from the default simpset by
  3919 `Delsplits [split_if]' or remove it in a specific call of the
  3920 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3921 other case splitting rules to/from the default simpset: every datatype
  3922 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3923 t is the name of the datatype).
  3924 
  3925 * Classical reasoner / Simplifier combination: new force_tac (and
  3926 derivatives Force_tac, force) combines rewriting and classical
  3927 reasoning (and whatever other tools) similarly to auto_tac, but is
  3928 aimed to solve the given subgoal completely.
  3929 
  3930 
  3931 *** General ***
  3932 
  3933 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3934 and `goalw': the theory is no longer needed as an explicit argument -
  3935 the current theory context is used; assumptions are no longer returned
  3936 at the ML-level unless one of them starts with ==> or !!; it is
  3937 recommended to convert to these new commands using isatool fixgoal
  3938 (backup your sources first!);
  3939 
  3940 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3941 the current theory context, and 'theory' to lookup stored theories;
  3942 
  3943 * new theory section 'locale' for declaring constants, assumptions and
  3944 definitions that have local scope;
  3945 
  3946 * new theory section 'nonterminals' for purely syntactic types;
  3947 
  3948 * new theory section 'setup' for generic ML setup functions
  3949 (e.g. package initialization);
  3950 
  3951 * the distribution now includes Isabelle icons: see
  3952 lib/logo/isabelle-{small,tiny}.xpm;
  3953 
  3954 * isatool install - install binaries with absolute references to
  3955 ISABELLE_HOME/bin;
  3956 
  3957 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3958 
  3959 * print mode 'emacs' reserved for Isamode;
  3960 
  3961 * support multiple print (ast) translations per constant name;
  3962 
  3963 * theorems involving oracles are now printed with a suffixed [!];
  3964 
  3965 
  3966 *** HOL ***
  3967 
  3968 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3969 
  3970 * HOL/inductive package reorganized and improved: now supports mutual
  3971 definitions such as
  3972 
  3973   inductive EVEN ODD
  3974     intrs
  3975       null "0 : EVEN"
  3976       oddI "n : EVEN ==> Suc n : ODD"
  3977       evenI "n : ODD ==> Suc n : EVEN"
  3978 
  3979 new theorem list "elims" contains an elimination rule for each of the
  3980 recursive sets; inductive definitions now handle disjunctive premises
  3981 correctly (also ZF);
  3982 
  3983 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3984 "mutual_induct" no longer exists - the induction rule is always
  3985 contained in "induct";
  3986 
  3987 
  3988 * HOL/datatype package re-implemented and greatly improved: now
  3989 supports mutually recursive datatypes such as
  3990 
  3991   datatype
  3992     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3993             | SUM ('a aexp) ('a aexp)
  3994             | DIFF ('a aexp) ('a aexp)
  3995             | NUM 'a
  3996   and
  3997     'a bexp = LESS ('a aexp) ('a aexp)
  3998             | AND ('a bexp) ('a bexp)
  3999             | OR ('a bexp) ('a bexp)
  4000 
  4001 as well as indirectly recursive datatypes such as
  4002 
  4003   datatype
  4004     ('a, 'b) term = Var 'a
  4005                   | App 'b ((('a, 'b) term) list)
  4006 
  4007 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4008 induction on mutually / indirectly recursive datatypes.
  4009 
  4010 Primrec equations are now stored in theory and can be accessed via
  4011 <function_name>.simps.
  4012 
  4013 INCOMPATIBILITIES:
  4014 
  4015   - Theories using datatypes must now have theory Datatype as an
  4016     ancestor.
  4017   - The specific <typename>.induct_tac no longer exists - use the
  4018     generic induct_tac instead.
  4019   - natE has been renamed to nat.exhaust - use exhaust_tac
  4020     instead of res_inst_tac ... natE. Note that the variable
  4021     names in nat.exhaust differ from the names in natE, this
  4022     may cause some "fragile" proofs to fail.
  4023   - The theorems split_<typename>_case and split_<typename>_case_asm
  4024     have been renamed to <typename>.split and <typename>.split_asm.
  4025   - Since default sorts of type variables are now handled correctly,
  4026     some datatype definitions may have to be annotated with explicit
  4027     sort constraints.
  4028   - Primrec definitions no longer require function name and type
  4029     of recursive argument.
  4030 
  4031 Consider using isatool fixdatatype to adapt your theories and proof
  4032 scripts to the new package (backup your sources first!).
  4033 
  4034 
  4035 * HOL/record package: considerably improved implementation; now
  4036 includes concrete syntax for record types, terms, updates; theorems
  4037 for surjective pairing and splitting !!-bound record variables; proof
  4038 support is as follows:
  4039 
  4040   1) standard conversions (selectors or updates applied to record
  4041 constructor terms) are part of the standard simpset;
  4042 
  4043   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4044 made part of standard simpset and claset via addIffs;
  4045 
  4046   3) a tactic for record field splitting (record_split_tac) is part of
  4047 the standard claset (addSWrapper);
  4048 
  4049 To get a better idea about these rules you may retrieve them via
  4050 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4051 the name of your record type.
  4052 
  4053 The split tactic 3) conceptually simplifies by the following rule:
  4054 
  4055   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4056 
  4057 Thus any record variable that is bound by meta-all will automatically
  4058 blow up into some record constructor term, consequently the
  4059 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4060 solve record problems automatically.
  4061 
  4062 
  4063 * reorganized the main HOL image: HOL/Integ and String loaded by
  4064 default; theory Main includes everything;
  4065 
  4066 * automatic simplification of integer sums and comparisons, using cancellation;
  4067 
  4068 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4069 
  4070 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4071 
  4072 * many new identities for unions, intersections, set difference, etc.;
  4073 
  4074 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4075 called split_if, split_split, split_sum_case and split_nat_case (to go
  4076 with add/delsplits);
  4077 
  4078 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4079 (?x::unit) = (); this is made part of the default simpset, which COULD
  4080 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4081 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4082 unit_abs_eta_conv is added in order to counter the effect of
  4083 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4084 %u.f();
  4085 
  4086 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4087 makes more sense);
  4088 
  4089 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4090   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4091   disjointness reasoning but breaking a few old proofs.
  4092 
  4093 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4094 to 'converse' from 'inverse' (for compatibility with ZF and some
  4095 literature);
  4096 
  4097 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4098 the well-founded relation;
  4099 
  4100 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4101     Compl A.  The "Compl" syntax remains available as input syntax for this
  4102     release ONLY.
  4103 
  4104 * HOL/Update: new theory of function updates:
  4105     f(a:=b) == %x. if x=a then b else f x
  4106 may also be iterated as in f(a:=b,c:=d,...);
  4107 
  4108 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4109 
  4110 * HOL/List:
  4111   - new function list_update written xs[i:=v] that updates the i-th
  4112     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4113   - new function `upt' written [i..j(] which generates the list
  4114     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4115     bound write [i..j], which is a shorthand for [i..j+1(].
  4116   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4117 
  4118 * HOL/Arith:
  4119   - removed 'pred' (predecessor) function;
  4120   - generalized some theorems about n-1;
  4121   - many new laws about "div" and "mod";
  4122   - new laws about greatest common divisors (see theory ex/Primes);
  4123 
  4124 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4125 instead of "inverse";
  4126 
  4127 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4128   of the multiset ordering;
  4129 
  4130 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4131   (not included by default);
  4132 
  4133 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4134 
  4135 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4136   programs, i.e. different program variables may have different types.
  4137 
  4138 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4139   [previously, this check worked only if the rewrite rule was unconditional]
  4140   Now rew can involve either definitions or equalities (either == or =).
  4141 
  4142 
  4143 *** ZF ***
  4144 
  4145 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4146   only the theorems proved on ZF.ML;
  4147 
  4148 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4149   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4150   disjointness reasoning but breaking a few old proofs.
  4151 
  4152 * ZF/Update: new theory of function updates
  4153     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4154   may also be iterated as in f(a:=b,c:=d,...);
  4155 
  4156 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4157 
  4158 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4159   [previously, this check worked only if the rewrite rule was unconditional]
  4160   Now rew can involve either definitions or equalities (either == or =).
  4161 
  4162 * case_tac provided for compatibility with HOL
  4163     (like the old excluded_middle_tac, but with subgoals swapped)
  4164 
  4165 
  4166 *** Internal programming interfaces ***
  4167 
  4168 * Pure: several new basic modules made available for general use, see
  4169 also src/Pure/README;
  4170 
  4171 * improved the theory data mechanism to support encapsulation (data
  4172 kind name replaced by private Object.kind, acting as authorization
  4173 key); new type-safe user interface via functor TheoryDataFun; generic
  4174 print_data function becomes basically useless;
  4175 
  4176 * removed global_names compatibility flag -- all theory declarations
  4177 are qualified by default;
  4178 
  4179 * module Pure/Syntax now offers quote / antiquote translation
  4180 functions (useful for Hoare logic etc. with implicit dependencies);
  4181 see HOL/ex/Antiquote for an example use;
  4182 
  4183 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4184 cterm -> thm;
  4185 
  4186 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4187 subgoal;
  4188 
  4189 * Display.print_goals function moved to Locale.print_goals;
  4190 
  4191 * standard print function for goals supports current_goals_markers
  4192 variable for marking begin of proof, end of proof, start of goal; the
  4193 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4194 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4195 for example;
  4196 
  4197 
  4198 
  4199 New in Isabelle98 (January 1998)
  4200 --------------------------------
  4201 
  4202 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4203 
  4204 * changed lexical syntax of terms / types: dots made part of long
  4205 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4206 
  4207 * simpset (and claset) reference variable replaced by functions
  4208 simpset / simpset_ref;
  4209 
  4210 * no longer supports theory aliases (via merge) and non-trivial
  4211 implicit merge of thms' signatures;
  4212 
  4213 * most internal names of constants changed due to qualified names;
  4214 
  4215 * changed Pure/Sequence interface (see Pure/seq.ML);
  4216 
  4217 
  4218 *** General Changes ***
  4219 
  4220 * hierachically structured name spaces (for consts, types, axms, thms
  4221 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4222 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4223 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4224 long_names for fully qualified output names; NOTE: ML programs
  4225 (special tactics, packages etc.) referring to internal names may have
  4226 to be adapted to cope with fully qualified names; in case of severe
  4227 backward campatibility problems try setting 'global_names' at compile
  4228 time to have enrything declared within a flat name space; one may also
  4229 fine tune name declarations in theories via the 'global' and 'local'
  4230 section;
  4231 
  4232 * reimplemented the implicit simpset and claset using the new anytype
  4233 data filed in signatures; references simpset:simpset ref etc. are
  4234 replaced by functions simpset:unit->simpset and
  4235 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4236 to patch your ML files accordingly;
  4237 
  4238 * HTML output now includes theory graph data for display with Java
  4239 applet or isatool browser; data generated automatically via isatool
  4240 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4241 
  4242 * defs may now be conditional; improved rewrite_goals_tac to handle
  4243 conditional equations;
  4244 
  4245 * defs now admits additional type arguments, using TYPE('a) syntax;
  4246 
  4247 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4248 creates a new theory node; implicit merge of thms' signatures is
  4249 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4250 transfer:theory->thm->thm in (rare) cases;
  4251 
  4252 * improved handling of draft signatures / theories; draft thms (and
  4253 ctyps, cterms) are automatically promoted to real ones;
  4254 
  4255 * slightly changed interfaces for oracles: admit many per theory, named
  4256 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4257 
  4258 * print_goals: optional output of const types (set show_consts and
  4259 show_types);
  4260 
  4261 * improved output of warnings (###) and errors (***);
  4262 
  4263 * subgoal_tac displays a warning if the new subgoal has type variables;
  4264 
  4265 * removed old README and Makefiles;
  4266 
  4267 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4268 
  4269 * removed obsolete init_pps and init_database;
  4270 
  4271 * deleted the obsolete tactical STATE, which was declared by
  4272     fun STATE tacfun st = tacfun st st;
  4273 
  4274 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4275 (which abbreviates $HOME);
  4276 
  4277 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4278 use isatool fixseq to adapt your ML programs (this works for fully
  4279 qualified references to the Sequence structure only!);
  4280 
  4281 * use_thy no longer requires writable current directory; it always
  4282 reloads .ML *and* .thy file, if either one is out of date;
  4283 
  4284 
  4285 *** Classical Reasoner ***
  4286 
  4287 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4288 tactics that use classical reasoning to simplify a subgoal without
  4289 splitting it into several subgoals;
  4290 
  4291 * Safe_tac: like safe_tac but uses the default claset;
  4292 
  4293 
  4294 *** Simplifier ***
  4295 
  4296 * added simplification meta rules:
  4297     (asm_)(full_)simplify: simpset -> thm -> thm;
  4298 
  4299 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4300 logics (again);
  4301 
  4302 * added prems argument to simplification procedures;
  4303 
  4304 * HOL, FOL, ZF: added infix function `addsplits':
  4305   instead of `<simpset> setloop (split_tac <thms>)'
  4306   you can simply write `<simpset> addsplits <thms>'
  4307 
  4308 
  4309 *** Syntax ***
  4310 
  4311 * TYPE('a) syntax for type reflection terms;
  4312 
  4313 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4314 
  4315 * pretty printer: changed order of mixfix annotation preference (again!);
  4316 
  4317 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4318 
  4319 
  4320 *** HOL ***
  4321 
  4322 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4323   with `addloop' of the simplifier to faciliate case splitting in premises.
  4324 
  4325 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4326 
  4327 * HOL/Auth: new protocol proofs including some for the Internet
  4328   protocol TLS;
  4329 
  4330 * HOL/Map: new theory of `maps' a la VDM;
  4331 
  4332 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4333 cancelling out common nat summands from =, <, <= (in)equalities, or
  4334 differences; simplification procedures nat_cancel_factor for
  4335 cancelling common factor from =, <, <= (in)equalities over natural
  4336 sums; nat_cancel contains both kinds of procedures, it is installed by
  4337 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4338 
  4339 * HOL/simplifier: terms of the form
  4340   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4341   are rewritten to
  4342   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4343   and those of the form
  4344   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4345   are rewritten to
  4346   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4347 
  4348 * HOL/datatype
  4349   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4350 
  4351   P(t_case f1 ... fn x) =
  4352      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4353         ...
  4354        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4355      )
  4356 
  4357   and a theorem `split_t_case_asm' of the form
  4358 
  4359   P(t_case f1 ... fn x) =
  4360     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4361         ...
  4362        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4363      )
  4364   which can be added to a simpset via `addsplits'. The existing theorems
  4365   expand_list_case and expand_option_case have been renamed to
  4366   split_list_case and split_option_case.
  4367 
  4368 * HOL/Arithmetic:
  4369   - `pred n' is automatically converted to `n-1'.
  4370     Users are strongly encouraged not to use `pred' any longer,
  4371     because it will disappear altogether at some point.
  4372   - Users are strongly encouraged to write "0 < n" rather than
  4373     "n ~= 0". Theorems and proof tools have been modified towards this
  4374     `standard'.
  4375 
  4376 * HOL/Lists:
  4377   the function "set_of_list" has been renamed "set" (and its theorems too);
  4378   the function "nth" now takes its arguments in the reverse order and
  4379   has acquired the infix notation "!" as in "xs!n".
  4380 
  4381 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4382 
  4383 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4384   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4385 
  4386 * HOL/record: extensible records with schematic structural subtyping
  4387 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4388 still lacks various theorems and concrete record syntax;
  4389 
  4390 
  4391 *** HOLCF ***
  4392 
  4393 * removed "axioms" and "generated by" sections;
  4394 
  4395 * replaced "ops" section by extended "consts" section, which is capable of
  4396   handling the continuous function space "->" directly;
  4397 
  4398 * domain package:
  4399   . proves theorems immediately and stores them in the theory,
  4400   . creates hierachical name space,
  4401   . now uses normal mixfix annotations (instead of cinfix...),
  4402   . minor changes to some names and values (for consistency),
  4403   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4404   . separator between mutual domain defs: changed "," to "and",
  4405   . improved handling of sort constraints;  now they have to
  4406     appear on the left-hand side of the equations only;
  4407 
  4408 * fixed LAM <x,y,zs>.b syntax;
  4409 
  4410 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4411 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4412 
  4413 
  4414 *** FOL and ZF ***
  4415 
  4416 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4417   with `addloop' of the simplifier to faciliate case splitting in premises.
  4418 
  4419 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4420 in HOL, they strip ALL and --> from proved theorems;
  4421 
  4422 
  4423 
  4424 New in Isabelle94-8 (May 1997)
  4425 ------------------------------
  4426 
  4427 *** General Changes ***
  4428 
  4429 * new utilities to build / run / maintain Isabelle etc. (in parts
  4430 still somewhat experimental); old Makefiles etc. still functional;
  4431 
  4432 * new 'Isabelle System Manual';
  4433 
  4434 * INSTALL text, together with ./configure and ./build scripts;
  4435 
  4436 * reimplemented type inference for greater efficiency, better error
  4437 messages and clean internal interface;
  4438 
  4439 * prlim command for dealing with lots of subgoals (an easier way of
  4440 setting goals_limit);
  4441 
  4442 
  4443 *** Syntax ***
  4444 
  4445 * supports alternative (named) syntax tables (parser and pretty
  4446 printer); internal interface is provided by add_modesyntax(_i);
  4447 
  4448 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4449 be used in conjunction with the Isabelle symbol font; uses the
  4450 "symbols" syntax table;
  4451 
  4452 * added token_translation interface (may translate name tokens in
  4453 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4454 the current print_mode); IMPORTANT: user print translation functions
  4455 are responsible for marking newly introduced bounds
  4456 (Syntax.mark_boundT);
  4457 
  4458 * token translations for modes "xterm" and "xterm_color" that display
  4459 names in bold, underline etc. or colors (which requires a color
  4460 version of xterm);
  4461 
  4462 * infixes may now be declared with names independent of their syntax;
  4463 
  4464 * added typed_print_translation (like print_translation, but may
  4465 access type of constant);
  4466 
  4467 
  4468 *** Classical Reasoner ***
  4469 
  4470 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4471 some limitations.  Blast_tac...
  4472   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4473   + ignores elimination rules that don't have the correct format
  4474         (the conclusion MUST be a formula variable)
  4475   + ignores types, which can make HOL proofs fail
  4476   + rules must not require higher-order unification, e.g. apply_type in ZF
  4477     [message "Function Var's argument not a bound variable" relates to this]
  4478   + its proof strategy is more general but can actually be slower
  4479 
  4480 * substitution with equality assumptions no longer permutes other
  4481 assumptions;
  4482 
  4483 * minor changes in semantics of addafter (now called addaltern); renamed
  4484 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4485 (and access functions for it);
  4486 
  4487 * improved combination of classical reasoner and simplifier:
  4488   + functions for handling clasimpsets
  4489   + improvement of addss: now the simplifier is called _after_ the
  4490     safe steps.
  4491   + safe variant of addss called addSss: uses safe simplifications
  4492     _during_ the safe steps. It is more complete as it allows multiple
  4493     instantiations of unknowns (e.g. with slow_tac).
  4494 
  4495 *** Simplifier ***
  4496 
  4497 * added interface for simplification procedures (functions that
  4498 produce *proven* rewrite rules on the fly, depending on current
  4499 redex);
  4500 
  4501 * ordering on terms as parameter (used for ordered rewriting);
  4502 
  4503 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4504 
  4505 * the solver is now split into a safe and an unsafe part.
  4506 This should be invisible for the normal user, except that the
  4507 functions setsolver and addsolver have been renamed to setSolver and
  4508 addSolver; added safe_asm_full_simp_tac;
  4509 
  4510 
  4511 *** HOL ***
  4512 
  4513 * a generic induction tactic `induct_tac' which works for all datatypes and
  4514 also for type `nat';
  4515 
  4516 * a generic case distinction tactic `exhaust_tac' which works for all
  4517 datatypes and also for type `nat';
  4518 
  4519 * each datatype comes with a function `size';
  4520 
  4521 * patterns in case expressions allow tuple patterns as arguments to
  4522 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4523 
  4524 * primrec now also works with type nat;
  4525 
  4526 * recdef: a new declaration form, allows general recursive functions to be
  4527 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4528 
  4529 * the constant for negation has been renamed from "not" to "Not" to
  4530 harmonize with FOL, ZF, LK, etc.;
  4531 
  4532 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4533 infinite lists;
  4534 
  4535 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4536 
  4537 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4538 problems in commutative rings, using axiomatic type classes for + and *;
  4539 
  4540 * more examples in HOL/MiniML and HOL/Auth;
  4541 
  4542 * more default rewrite rules for quantifiers, union/intersection;
  4543 
  4544 * a new constant `arbitrary == @x.False';
  4545 
  4546 * HOLCF/IOA replaces old HOL/IOA;
  4547 
  4548 * HOLCF changes: derived all rules and arities
  4549   + axiomatic type classes instead of classes
  4550   + typedef instead of faking type definitions
  4551   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4552   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4553   + eliminated the types void, one, tr
  4554   + use unit lift and bool lift (with translations) instead of one and tr
  4555   + eliminated blift from Lift3.thy (use Def instead of blift)
  4556   all eliminated rules are derived as theorems --> no visible changes ;
  4557 
  4558 
  4559 *** ZF ***
  4560 
  4561 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4562 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4563 as ZF_cs addSIs [equalityI];
  4564 
  4565 
  4566 
  4567 New in Isabelle94-7 (November 96)
  4568 ---------------------------------
  4569 
  4570 * allowing negative levels (as offsets) in prlev and choplev;
  4571 
  4572 * super-linear speedup for large simplifications;
  4573 
  4574 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4575 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4576 FAIL); can suppress it using the command Delsimps (ex_simps @
  4577 all_simps); De Morgan laws are also now included, by default;
  4578 
  4579 * improved printing of ==>  :  ~:
  4580 
  4581 * new object-logic "Sequents" adds linear logic, while replacing LK
  4582 and Modal (thanks to Sara Kalvala);
  4583 
  4584 * HOL/Auth: correctness proofs for authentication protocols;
  4585 
  4586 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4587 examples on HOL/Auth);
  4588 
  4589 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4590 the rewriter and classical reasoner simultaneously;
  4591 
  4592 * function uresult no longer returns theorems in "standard" format;
  4593 regain previous version by: val uresult = standard o uresult;
  4594 
  4595 
  4596 
  4597 New in Isabelle94-6
  4598 -------------------
  4599 
  4600 * oracles -- these establish an interface between Isabelle and trusted
  4601 external reasoners, which may deliver results as theorems;
  4602 
  4603 * proof objects (in particular record all uses of oracles);
  4604 
  4605 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4606 
  4607 * "constdefs" section in theory files;
  4608 
  4609 * "primrec" section (HOL) no longer requires names;
  4610 
  4611 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4612 
  4613 
  4614 
  4615 New in Isabelle94-5
  4616 -------------------
  4617 
  4618 * reduced space requirements;
  4619 
  4620 * automatic HTML generation from theories;
  4621 
  4622 * theory files no longer require "..." (quotes) around most types;
  4623 
  4624 * new examples, including two proofs of the Church-Rosser theorem;
  4625 
  4626 * non-curried (1994) version of HOL is no longer distributed;
  4627 
  4628 
  4629 
  4630 New in Isabelle94-4
  4631 -------------------
  4632 
  4633 * greatly reduced space requirements;
  4634 
  4635 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4636 
  4637 * searchable theorem database (see the section "Retrieving theorems" on
  4638 page 8 of the Reference Manual);
  4639 
  4640 * new examples, including Grabczewski's monumental case study of the
  4641 Axiom of Choice;
  4642 
  4643 * The previous version of HOL renamed to Old_HOL;
  4644 
  4645 * The new version of HOL (previously called CHOL) uses a curried syntax
  4646 for functions.  Application looks like f a b instead of f(a,b);
  4647 
  4648 * Mutually recursive inductive definitions finally work in HOL;
  4649 
  4650 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4651 translates to the operator "split";
  4652 
  4653 
  4654 
  4655 New in Isabelle94-3
  4656 -------------------
  4657 
  4658 * new infix operator, addss, allowing the classical reasoner to
  4659 perform simplification at each step of its search.  Example:
  4660         fast_tac (cs addss ss)
  4661 
  4662 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4663 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4664 look like (a,b) instead of <a,b>;
  4665 
  4666 * PLEASE NOTE: CHOL will eventually replace HOL!
  4667 
  4668 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4669 It translates to the operator "split".  A new theory of integers is available;
  4670 
  4671 * In ZF, integer numerals now denote two's-complement binary integers.
  4672 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4673 
  4674 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4675 of the Axiom of Choice;
  4676 
  4677 
  4678 
  4679 New in Isabelle94-2
  4680 -------------------
  4681 
  4682 * Significantly faster resolution;
  4683 
  4684 * the different sections in a .thy file can now be mixed and repeated
  4685 freely;
  4686 
  4687 * Database of theorems for FOL, HOL and ZF.  New
  4688 commands including qed, qed_goal and bind_thm store theorems in the database.
  4689 
  4690 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4691 a given theory (thms_of), or find out what theory a theorem was proved in
  4692 (theory_of_thm);
  4693 
  4694 * Bugs fixed in the inductive definition and datatype packages;
  4695 
  4696 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4697 and HOL_dup_cs obsolete;
  4698 
  4699 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4700 have been removed;
  4701 
  4702 * Simpler definition of function space in ZF;
  4703 
  4704 * new results about cardinal and ordinal arithmetic in ZF;
  4705 
  4706 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4707 types;
  4708 
  4709 
  4710 $Id$