NEWS
author haftmann
Thu May 17 19:49:40 2007 +0200 (2007-05-17)
changeset 22997 d4f3b015b50b
parent 22972 3e96b98d37c6
child 23013 c38c9039dc13
permissions -rw-r--r--
canonical prefixing of class constants
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true).
    12 
    13 * Theory syntax: the header format ``theory A = B + C:'' has been
    14 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    15 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    16 
    17 * Theory syntax: the old non-Isar theory file format has been
    18 discontinued altogether.  Note that ML proof scripts may still be used
    19 with Isar theories; migration is usually quite simple with the ML
    20 function use_legacy_bindings.  INCOMPATIBILITY.
    21 
    22 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    23 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    24 quotes.
    25 
    26 * Legacy goal package: reduced interface to the bare minimum required
    27 to keep existing proof scripts running.  Most other user-level
    28 functions are now part of the OldGoals structure, which is *not* open
    29 by default (consider isatool expandshort before open OldGoals).
    30 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    31 these tend to cause confusion about the actual goal (!) context being
    32 used here, which is not necessarily the same as the_context().
    33 
    34 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    35 
    36 * Proof General interface: A search form for the "Find Theorems" command is
    37 now available via C-c C-a C-f.  The old minibuffer interface is available
    38 via C-c C-a C-m.  Variable proof-find-theorems-command (customizable via
    39 'Proof-General -> Advanced -> Internals -> Prover Config') controls the
    40 default behavior of 'ProofGeneral -> Find Theorems' (C-c C-f): set to
    41 isar-find-theorems-form or isar-find-theorems-minibuffer.
    42 
    43 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    44 by default, which means that "prems" (and also "fixed variables") are
    45 suppressed from proof state output.  Note that the ProofGeneral
    46 settings mechanism allows to change and save options persistently, but
    47 older versions of Isabelle will fail to start up if a negative prems
    48 limit is imposed.
    49 
    50 * Local theory targets may be specified by non-nested blocks of
    51 ``context/locale/class ... begin'' followed by ``end''.  The body may
    52 contain definitions, theorems etc., including any derived mechanism
    53 that has been implemented on top of these primitives.  This concept
    54 generalizes the existing ``theorem (in ...)'' towards more versatility
    55 and scalability.
    56 
    57 * Proof General interface: proper undo of final 'end' command;
    58 discontinued Isabelle/classic mode (ML proof scripts).
    59 
    60 
    61 *** Document preparation ***
    62 
    63 * Added antiquotation @{theory name} which prints the given name,
    64 after checking that it refers to a valid ancestor theory in the
    65 current context.
    66 
    67 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    68 check the given source text as ML type/structure, printing verbatim.
    69 
    70 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    71 "c args == rhs" given in the current context.  (Any number of
    72 arguments may be given on the LHS.)
    73 
    74 
    75 
    76 *** Pure ***
    77 
    78 * code generator: consts in 'consts_code' Isar commands are now referred
    79   to by usual term syntax (including optional type annotations).
    80 
    81 * code generator: 
    82   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    83     explicitly to the table of defining equations
    84   - primitive definitions are not used as defining equations by default any longer
    85   - defining equations are now definitly restricted to meta "==" and object
    86         equality "="
    87   - HOL theories have been adopted accordingly
    88 
    89 * class_package.ML offers a combination of axclasses and locales to
    90 achieve Haskell-like type classes in Isabelle.  See
    91 HOL/ex/Classpackage.thy for examples.
    92 
    93 * Yet another code generator framework allows to generate executable
    94 code for ML and Haskell (including "class"es).  A short usage sketch:
    95 
    96     internal compilation:
    97         code_gen <list of constants (term syntax)> (SML #)
    98     writing SML code to a file:
    99         code_gen <list of constants (term syntax)> (SML <filename>)
   100     writing OCaml code to a file:
   101         code_gen <list of constants (term syntax)> (OCaml <filename>)
   102     writing Haskell code to a bunch of files:
   103         code_gen <list of constants (term syntax)> (Haskell <filename>)
   104 
   105 Reasonable default setup of framework in HOL/Main.
   106 
   107 Theorem attributs for selecting and transforming function equations theorems:
   108 
   109     [code fun]:        select a theorem as function equation for a specific constant
   110     [code fun del]:    deselect a theorem as function equation for a specific constant
   111     [code inline]:     select an equation theorem for unfolding (inlining) in place
   112     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   113 
   114 User-defined serializations (target in {SML, OCaml, Haskell}):
   115 
   116     code_const <and-list of constants (term syntax)>
   117       {(target) <and-list of const target syntax>}+
   118 
   119     code_type <and-list of type constructors>
   120       {(target) <and-list of type target syntax>}+
   121 
   122     code_instance <and-list of instances>
   123       {(target)}+
   124         where instance ::= <type constructor> :: <class>
   125 
   126     code_class <and_list of classes>
   127       {(target) <and-list of class target syntax>}+
   128         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   129 
   130 code_instance and code_class only apply to target Haskell.
   131 
   132 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   133 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   134 
   135 * Command 'no_translations' removes translation rules from theory
   136 syntax.
   137 
   138 * Overloaded definitions are now actually checked for acyclic
   139 dependencies.  The overloading scheme is slightly more general than
   140 that of Haskell98, although Isabelle does not demand an exact
   141 correspondence to type class and instance declarations.
   142 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   143 exotic versions of overloading -- at the discretion of the user!
   144 
   145 Polymorphic constants are represented via type arguments, i.e. the
   146 instantiation that matches an instance against the most general
   147 declaration given in the signature.  For example, with the declaration
   148 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   149 as c(nat).  Overloading is essentially simultaneous structural
   150 recursion over such type arguments.  Incomplete specification patterns
   151 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   152 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   153 Command 'print_theory' outputs the normalized system of recursive
   154 equations, see section "definitions".
   155 
   156 * Isar: improper proof element 'guess' is like 'obtain', but derives
   157 the obtained context from the course of reasoning!  For example:
   158 
   159   assume "EX x y. A x & B y"   -- "any previous fact"
   160   then guess x and y by clarify
   161 
   162 This technique is potentially adventurous, depending on the facts and
   163 proof tools being involved here.
   164 
   165 * Isar: known facts from the proof context may be specified as literal
   166 propositions, using ASCII back-quote syntax.  This works wherever
   167 named facts used to be allowed so far, in proof commands, proof
   168 methods, attributes etc.  Literal facts are retrieved from the context
   169 according to unification of type and term parameters.  For example,
   170 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   171 theorems in the current context, then these are valid literal facts:
   172 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   173 
   174 There is also a proof method "fact" which does the same composition
   175 for explicit goal states, e.g. the following proof texts coincide with
   176 certain special cases of literal facts:
   177 
   178   have "A" by fact                 ==  note `A`
   179   have "A ==> B" by fact           ==  note `A ==> B`
   180   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   181   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   182 
   183 * Isar: ":" (colon) is no longer a symbolic identifier character in
   184 outer syntax.  Thus symbolic identifiers may be used without
   185 additional white space in declarations like this: ``assume *: A''.
   186 
   187 * Isar: 'print_facts' prints all local facts of the current context,
   188 both named and unnamed ones.
   189 
   190 * Isar: 'def' now admits simultaneous definitions, e.g.:
   191 
   192   def x == "t" and y == "u"
   193 
   194 * Isar: added command 'unfolding', which is structurally similar to
   195 'using', but affects both the goal state and facts by unfolding given
   196 rewrite rules.  Thus many occurrences of the 'unfold' method or
   197 'unfolded' attribute may be replaced by first-class proof text.
   198 
   199 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   200 and command 'unfolding' now all support object-level equalities
   201 (potentially conditional).  The underlying notion of rewrite rule is
   202 analogous to the 'rule_format' attribute, but *not* that of the
   203 Simplifier (which is usually more generous).
   204 
   205 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   206 method expression within a sandbox consisting of the first N
   207 sub-goals, which need to exist.  For example, ``simp_all [3]''
   208 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   209 simplifies all new goals that emerge from applying rule foo to the
   210 originally first one.
   211 
   212 * Isar: schematic goals are no longer restricted to higher-order
   213 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   214 expected.
   215 
   216 * Isar: the conclusion of a long theorem statement is now either
   217 'shows' (a simultaneous conjunction, as before), or 'obtains'
   218 (essentially a disjunction of cases with local parameters and
   219 assumptions).  The latter allows to express general elimination rules
   220 adequately; in this notation common elimination rules look like this:
   221 
   222   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   223     assumes "EX x. P x"
   224     obtains x where "P x"
   225 
   226   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   227     assumes "A & B"
   228     obtains A and B
   229 
   230   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   231     assumes "A | B"
   232     obtains
   233       A
   234     | B
   235 
   236 The subsequent classical rules even refer to the formal "thesis"
   237 explicitly:
   238 
   239   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   240     obtains "~ thesis"
   241 
   242   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   243     obtains "thesis ==> something"
   244 
   245 The actual proof of an 'obtains' statement is analogous to that of the
   246 Isar proof element 'obtain', only that there may be several cases.
   247 Optional case names may be specified in parentheses; these will be
   248 available both in the present proof and as annotations in the
   249 resulting rule, for later use with the 'cases' method (cf. attribute
   250 case_names).
   251 
   252 * Isar: the assumptions of a long theorem statement are available as
   253 "assms" fact in the proof context.  This is more appropriate than the
   254 (historical) "prems", which refers to all assumptions of the current
   255 context, including those from the target locale, proof body etc.
   256 
   257 * Isar: 'print_statement' prints theorems from the current theory or
   258 proof context in long statement form, according to the syntax of a
   259 top-level lemma.
   260 
   261 * Isar: 'obtain' takes an optional case name for the local context
   262 introduction rule (default "that").
   263 
   264 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   265 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   266 to occur.
   267 
   268 * Pure: syntax "CONST name" produces a fully internalized constant
   269 according to the current context.  This is particularly useful for
   270 syntax translations that should refer to internal constant
   271 representations independently of name spaces.
   272 
   273 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   274 instead of "FOO ". This allows multiple binder declarations to coexist
   275 in the same context.  INCOMPATIBILITY.
   276 
   277 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   278 primitive that also works in a locale context (both for constants and
   279 fixed variables).  Type declaration and internal syntactic
   280 representation of given constants retrieved from the context.
   281 
   282 * Isar/locales: new derived specification elements 'axiomatization',
   283 'definition', 'abbreviation', which support type-inference, admit
   284 object-level specifications (equality, equivalence).  See also the
   285 isar-ref manual.  Examples:
   286 
   287   axiomatization
   288     eq  (infix "===" 50) where
   289     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   290 
   291   definition "f x y = x + y + 1"
   292   definition g where "g x = f x x"
   293 
   294   abbreviation
   295     neq  (infix "=!=" 50) where
   296     "x =!= y == ~ (x === y)"
   297 
   298 These specifications may be also used in a locale context.  Then the
   299 constants being introduced depend on certain fixed parameters, and the
   300 constant name is qualified by the locale base name.  An internal
   301 abbreviation takes care for convenient input and output, making the
   302 parameters implicit and using the original short name.  See also
   303 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   304 entities from a monomorphic theory.
   305 
   306 Presently, abbreviations are only available 'in' a target locale, but
   307 not inherited by general import expressions.  Also note that
   308 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   309 'translations' in common applications.
   310 
   311 Concrete syntax is attached to specified constants in internal form,
   312 independently of name spaces.  The parse tree representation is
   313 slightly different -- use 'notation' instead of raw 'syntax', and
   314 'translations' with explicit "CONST" markup to accommodate this.
   315 
   316 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   317 the current context.  Print mode "no_abbrevs" prevents inversion of
   318 abbreviations on output.
   319 
   320 * Isar/locales: improved parameter handling:
   321 - use of locales "var" and "struct" no longer necessary;
   322 - parameter renamings are no longer required to be injective.
   323   This enables, for example, to define a locale for endomorphisms thus:
   324   locale endom = homom mult mult h.
   325 
   326 * Isar/locales: changed the way locales with predicates are defined.
   327 Instead of accumulating the specification, the imported expression is
   328 now an interpretation.  INCOMPATIBILITY: different normal form of
   329 locale expressions.  In particular, in interpretations of locales with
   330 predicates, goals repesenting already interpreted fragments are not
   331 removed automatically.  Use methods `intro_locales' and
   332 `unfold_locales'; see below.
   333 
   334 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   335 provide backward reasoning on locales predicates.  The methods are
   336 aware of interpretations and discharge corresponding goals.
   337 `intro_locales' is less aggressive then `unfold_locales' and does not
   338 unfold predicates to assumptions.
   339 
   340 * Isar/locales: the order in which locale fragments are accumulated
   341 has changed.  This enables to override declarations from fragments due
   342 to interpretations -- for example, unwanted simp rules.
   343 
   344 * Provers/induct: improved internal context management to support
   345 local fixes and defines on-the-fly.  Thus explicit meta-level
   346 connectives !! and ==> are rarely required anymore in inductive goals
   347 (using object-logic connectives for this purpose has been long
   348 obsolete anyway).  The subsequent proof patterns illustrate advanced
   349 techniques of natural induction; general datatypes and inductive sets
   350 work analogously (see also src/HOL/Lambda for realistic examples).
   351 
   352 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   353 parameters:
   354 
   355   lemma
   356     fixes n :: nat and x :: 'a
   357     assumes a: "A n x"
   358     shows "P n x"
   359     using a                     -- {* make induct insert fact a *}
   360   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   361     case 0
   362     show ?case sorry
   363   next
   364     case (Suc n)
   365     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   366     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   367     show ?case sorry
   368   qed
   369 
   370 (2) This is how to perform induction over ``expressions of a certain
   371 form'', using a locally defined inductive parameter n == "a x"
   372 together with strengthening (the latter is usually required to get
   373 sufficiently flexible induction hypotheses):
   374 
   375   lemma
   376     fixes a :: "'a => nat"
   377     assumes a: "A (a x)"
   378     shows "P (a x)"
   379     using a
   380   proof (induct n == "a x" arbitrary: x)
   381     ...
   382 
   383 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   384 particular technique.
   385 
   386 (3) This is how to perform existential reasoning ('obtains' or
   387 'obtain') by induction, while avoiding explicit object-logic
   388 encodings:
   389 
   390   lemma
   391     fixes n :: nat
   392     obtains x :: 'a where "P n x" and "Q n x"
   393   proof (induct n arbitrary: thesis)
   394     case 0
   395     obtain x where "P 0 x" and "Q 0 x" sorry
   396     then show thesis by (rule 0)
   397   next
   398     case (Suc n)
   399     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   400     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   401     then show thesis by (rule Suc.prems)
   402   qed
   403 
   404 Here the 'arbitrary: thesis' specification essentially modifies the
   405 scope of the formal thesis parameter, in order to the get the whole
   406 existence statement through the induction as expected.
   407 
   408 * Provers/induct: mutual induction rules are now specified as a list
   409 of rule sharing the same induction cases.  HOL packages usually
   410 provide foo_bar.inducts for mutually defined items foo and bar
   411 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   412 specify mutual induction rules differently, i.e. like this:
   413 
   414   (induct rule: foo_bar.inducts)
   415   (induct set: foo bar)
   416   (induct type: foo bar)
   417 
   418 The ML function ProjectRule.projections turns old-style rules into the
   419 new format.
   420 
   421 * Provers/induct: improved handling of simultaneous goals.  Instead of
   422 introducing object-level conjunction, the statement is now split into
   423 several conclusions, while the corresponding symbolic cases are
   424 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   425 explicitly.  For example:
   426 
   427   lemma
   428     fixes n :: nat
   429     shows "P n" and "Q n"
   430   proof (induct n)
   431     case 0 case 1
   432     show "P 0" sorry
   433   next
   434     case 0 case 2
   435     show "Q 0" sorry
   436   next
   437     case (Suc n) case 1
   438     note `P n` and `Q n`
   439     show "P (Suc n)" sorry
   440   next
   441     case (Suc n) case 2
   442     note `P n` and `Q n`
   443     show "Q (Suc n)" sorry
   444   qed
   445 
   446 The split into subcases may be deferred as follows -- this is
   447 particularly relevant for goal statements with local premises.
   448 
   449   lemma
   450     fixes n :: nat
   451     shows "A n ==> P n" and "B n ==> Q n"
   452   proof (induct n)
   453     case 0
   454     {
   455       case 1
   456       note `A 0`
   457       show "P 0" sorry
   458     next
   459       case 2
   460       note `B 0`
   461       show "Q 0" sorry
   462     }
   463   next
   464     case (Suc n)
   465     note `A n ==> P n` and `B n ==> Q n`
   466     {
   467       case 1
   468       note `A (Suc n)`
   469       show "P (Suc n)" sorry
   470     next
   471       case 2
   472       note `B (Suc n)`
   473       show "Q (Suc n)" sorry
   474     }
   475   qed
   476 
   477 If simultaneous goals are to be used with mutual rules, the statement
   478 needs to be structured carefully as a two-level conjunction, using
   479 lists of propositions separated by 'and':
   480 
   481   lemma
   482     shows "a : A ==> P1 a"
   483           "a : A ==> P2 a"
   484       and "b : B ==> Q1 b"
   485           "b : B ==> Q2 b"
   486           "b : B ==> Q3 b"
   487   proof (induct set: A B)
   488 
   489 * Provers/induct: support coinduction as well.  See
   490 src/HOL/Library/Coinductive_List.thy for various examples.
   491 
   492 * Attribute "symmetric" produces result with standardized schematic
   493 variables (index 0).  Potential INCOMPATIBILITY.
   494 
   495 * Simplifier: by default the simplifier trace only shows top level
   496 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   497 default. Thus there is less danger of being flooded by the trace. The
   498 trace indicates where parts have been suppressed.
   499   
   500 * Provers/classical: removed obsolete classical version of elim_format
   501 attribute; classical elim/dest rules are now treated uniformly when
   502 manipulating the claset.
   503 
   504 * Provers/classical: stricter checks to ensure that supplied intro,
   505 dest and elim rules are well-formed; dest and elim rules must have at
   506 least one premise.
   507 
   508 * Provers/classical: attributes dest/elim/intro take an optional
   509 weight argument for the rule (just as the Pure versions).  Weights are
   510 ignored by automated tools, but determine the search order of single
   511 rule steps.
   512 
   513 * Syntax: input syntax now supports dummy variable binding "%_. b",
   514 where the body does not mention the bound variable.  Note that dummy
   515 patterns implicitly depend on their context of bounds, which makes
   516 "{_. _}" match any set comprehension as expected.  Potential
   517 INCOMPATIBILITY -- parse translations need to cope with syntactic
   518 constant "_idtdummy" in the binding position.
   519 
   520 * Syntax: removed obsolete syntactic constant "_K" and its associated
   521 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   522 for example "A -> B" => "Pi A (%_. B)".
   523 
   524 * Pure: 'class_deps' command visualizes the subclass relation, using
   525 the graph browser tool.
   526 
   527 * Pure: 'print_theory' now suppresses entities with internal name
   528 (trailing "_") by default; use '!' option for full details.
   529 
   530 
   531 *** HOL ***
   532 
   533 * Constant renames due to introduction of canonical name prefixing for
   534   class package:
   535 
   536     HOL.abs ~> HOL.minus_class.abs
   537     HOL.divide ~> HOL.divide_class.divide
   538     Nat.power ~> Nat.power_class.power
   539     Nat.size ~> Nat.size_class.size
   540     Numeral.number_of ~> Numeral.number_class.number_of
   541 
   542 * case expressions and primrec: missing cases now mapped to "undefined"
   543 instead of "arbitrary"
   544 
   545 * new constant "undefined" with axiom "undefined x = undefined"
   546 
   547 * new class "default" with associated constant "default"
   548 
   549 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   550     when generating code.
   551 
   552 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   553     when generating code.
   554 
   555 * Library/Commutative_Ring.thy: switched from recdef to function package;
   556     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   557 
   558 * Some steps towards more uniform lattice theory development in HOL.
   559 
   560     constants "meet" and "join" now named "inf" and "sup"
   561     constant "Meet" now named "Inf"
   562 
   563     classes "meet_semilorder" and "join_semilorder" now named
   564       "lower_semilattice" and "upper_semilattice"
   565     class "lorder" now named "lattice"
   566     class "comp_lat" now named "complete_lattice"
   567 
   568     Instantiation of lattice classes allows explicit definitions
   569     for "inf" and "sup" operations.
   570 
   571   INCOMPATIBILITY. Theorem renames:
   572 
   573     meet_left_le            ~> inf_le1
   574     meet_right_le           ~> inf_le2
   575     join_left_le            ~> sup_ge1
   576     join_right_le           ~> sup_ge2
   577     meet_join_le            ~> inf_sup_ord
   578     le_meetI                ~> le_infI
   579     join_leI                ~> le_supI
   580     le_meet                 ~> le_inf_iff
   581     le_join                 ~> ge_sup_conv
   582     meet_idempotent         ~> inf_idem
   583     join_idempotent         ~> sup_idem
   584     meet_comm               ~> inf_commute
   585     join_comm               ~> sup_commute
   586     meet_leI1               ~> le_infI1
   587     meet_leI2               ~> le_infI2
   588     le_joinI1               ~> le_supI1
   589     le_joinI2               ~> le_supI2
   590     meet_assoc              ~> inf_assoc
   591     join_assoc              ~> sup_assoc
   592     meet_left_comm          ~> inf_left_commute
   593     meet_left_idempotent    ~> inf_left_idem
   594     join_left_comm          ~> sup_left_commute
   595     join_left_idempotent    ~> sup_left_idem
   596     meet_aci                ~> inf_aci
   597     join_aci                ~> sup_aci
   598     le_def_meet             ~> le_iff_inf
   599     le_def_join             ~> le_iff_sup
   600     join_absorp2            ~> sup_absorb2
   601     join_absorp1            ~> sup_absorb1
   602     meet_absorp1            ~> inf_absorb1
   603     meet_absorp2            ~> inf_absorb2
   604     meet_join_absorp        ~> inf_sup_absorb
   605     join_meet_absorp        ~> sup_inf_absorb
   606     distrib_join_le         ~> distrib_sup_le
   607     distrib_meet_le         ~> distrib_inf_le
   608 
   609     add_meet_distrib_left   ~> add_inf_distrib_left
   610     add_join_distrib_left   ~> add_sup_distrib_left
   611     is_join_neg_meet        ~> is_join_neg_inf
   612     is_meet_neg_join        ~> is_meet_neg_sup
   613     add_meet_distrib_right  ~> add_inf_distrib_right
   614     add_join_distrib_right  ~> add_sup_distrib_right
   615     add_meet_join_distribs  ~> add_sup_inf_distribs
   616     join_eq_neg_meet        ~> sup_eq_neg_inf
   617     meet_eq_neg_join        ~> inf_eq_neg_sup
   618     add_eq_meet_join        ~> add_eq_inf_sup
   619     meet_0_imp_0            ~> inf_0_imp_0
   620     join_0_imp_0            ~> sup_0_imp_0
   621     meet_0_eq_0             ~> inf_0_eq_0
   622     join_0_eq_0             ~> sup_0_eq_0
   623     neg_meet_eq_join        ~> neg_inf_eq_sup
   624     neg_join_eq_meet        ~> neg_sup_eq_inf
   625     join_eq_if              ~> sup_eq_if
   626 
   627     mono_meet               ~> mono_inf
   628     mono_join               ~> mono_sup
   629     meet_bool_eq            ~> inf_bool_eq
   630     join_bool_eq            ~> sup_bool_eq
   631     meet_fun_eq             ~> inf_fun_eq
   632     join_fun_eq             ~> sup_fun_eq
   633     meet_set_eq             ~> inf_set_eq
   634     join_set_eq             ~> sup_set_eq
   635     meet1_iff               ~> inf1_iff
   636     meet2_iff               ~> inf2_iff
   637     meet1I                  ~> inf1I
   638     meet2I                  ~> inf2I
   639     meet1D1                 ~> inf1D1
   640     meet2D1                 ~> inf2D1
   641     meet1D2                 ~> inf1D2
   642     meet2D2                 ~> inf2D2
   643     meet1E                  ~> inf1E
   644     meet2E                  ~> inf2E
   645     join1_iff               ~> sup1_iff
   646     join2_iff               ~> sup2_iff
   647     join1I1                 ~> sup1I1
   648     join2I1                 ~> sup2I1
   649     join1I1                 ~> sup1I1
   650     join2I2                 ~> sup1I2
   651     join1CI                 ~> sup1CI
   652     join2CI                 ~> sup2CI
   653     join1E                  ~> sup1E
   654     join2E                  ~> sup2E
   655 
   656     is_meet_Meet            ~> is_meet_Inf
   657     Meet_bool_def           ~> Inf_bool_def
   658     Meet_fun_def            ~> Inf_fun_def
   659     Meet_greatest           ~> Inf_greatest
   660     Meet_lower              ~> Inf_lower
   661     Meet_set_def            ~> Inf_set_def
   662 
   663     listsp_meetI            ~> listsp_infI
   664     listsp_meet_eq          ~> listsp_inf_eq
   665 
   666     meet_min                ~> inf_min
   667     join_max                ~> sup_max
   668 
   669 * Classes "order" and "linorder": facts "refl", "trans" and
   670 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   671 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   672 
   673 * Classes "order" and "linorder": 
   674 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   675 proofs changed.
   676 
   677 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   678 INCOMPATIBILITY.
   679 
   680 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   681 INCOMPATIBILITY.
   682 
   683 * Added syntactic class "size"; overloaded constant "size" now has
   684 type "'a::size ==> bool"
   685 
   686 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   687 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   688 
   689 * Added method "lexicographic_order" automatically synthesizes
   690 termination relations as lexicographic combinations of size measures
   691 -- 'function' package.
   692 
   693 * HOL/records: generalised field-update to take a function on the
   694 field rather than the new value: r(|A := x|) is translated to A_update
   695 (K x) r The K-combinator that is internally used is called K_record.
   696 INCOMPATIBILITY: Usage of the plain update functions has to be
   697 adapted.
   698  
   699 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   700 0 * x = 0, which are required for a semiring.  Richer structures do
   701 not inherit from semiring_0 anymore, because this property is a
   702 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   703 semiring_0, there is more to prove, but this is mostly trivial.
   704 
   705 * axclass "recpower" was generalized to arbitrary monoids, not just
   706 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   707 commutativity or a semiring property, add the corresponding classes.
   708 
   709 * Unified locale partial_order with class definition (cf. theory
   710 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   711 
   712 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   713 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   714 Isar level, use abbreviations instead.
   715 
   716 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   717 rarely occuring name references (e.g. ``List.op mem.simps'') require
   718 renaming (e.g. ``List.memberl.simps'').
   719 
   720 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   721 INCOMPATIBILITY.
   722 
   723 * Added theory Code_Generator providing class 'eq', allowing for code
   724 generation with polymorphic equality.
   725 
   726 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   727 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   728 significant changes for setting up numeral syntax for types:
   729 
   730   - new constants Numeral.pred and Numeral.succ instead
   731       of former Numeral.bin_pred and Numeral.bin_succ.
   732   - Use integer operations instead of bin_add, bin_mult and so on.
   733   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   734   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   735 
   736 See HOL/Integ/IntArith.thy for an example setup.
   737 
   738 * New top level command 'normal_form' computes the normal form of a
   739 term that may contain free variables. For example ``normal_form
   740 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   741 suitable for heavy-duty computations because the functions are
   742 compiled to ML first.
   743 
   744 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   745 25 like -->); output depends on the "iff" print_mode, the default is
   746 "A = B" (with priority 50).
   747 
   748 * Renamed constants in HOL.thy and Orderings.thy:
   749     op +   ~> HOL.plus_class.plus
   750     op -   ~> HOL.minus_class.minus
   751     uminus ~> HOL.minus_class.uminus
   752     op *   ~> HOL.times_class.times
   753     op <   ~> Orderings.ord_class.less
   754     op <=  ~> Orderings.ord_class.less_eq
   755 
   756 Adaptions may be required in the following cases:
   757 
   758 a) User-defined constants using any of the names "plus", "minus", "times",
   759 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   760 may go wrong.
   761 INCOMPATIBILITY: use more specific names.
   762 
   763 b) Variables named "plus", "minus", "times", "less", "less_eq"
   764 INCOMPATIBILITY: use more specific names.
   765 
   766 c) Permutative equations (e.g. "a + b = b + a")
   767 Since the change of names also changes the order of terms, permutative
   768 rewrite rules may get applied in a different order. Experience shows that
   769 this is rarely the case (only two adaptions in the whole Isabelle
   770 distribution).
   771 INCOMPATIBILITY: rewrite proofs
   772 
   773 d) ML code directly refering to constant names
   774 This in general only affects hand-written proof tactics, simprocs and so on.
   775 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   776 of const_name ML antiquotations.
   777 
   778 * Relations less (<) and less_eq (<=) are also available on type bool.
   779 Modified syntax to disallow nesting without explicit parentheses,
   780 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   781 
   782 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   783 
   784 * Relation composition operator "op O" now has precedence 75 and binds
   785 stronger than union and intersection. INCOMPATIBILITY.
   786 
   787 * The old set interval syntax "{m..n(}" (and relatives) has been
   788 removed.  Use "{m..<n}" (and relatives) instead.
   789 
   790 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   791 "t = s" to False (by simproc "neq_simproc").  For backward
   792 compatibility this can be disabled by ML "reset use_neq_simproc".
   793 
   794 * "m dvd n" where m and n are numbers is evaluated to True/False by
   795 simp.
   796 
   797 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   798 
   799 * Theorem setsum_mult renamed to setsum_right_distrib.
   800 
   801 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   802 ``rule'' method.
   803 
   804 * Reimplemented methods ``sat'' and ``satx'', with several
   805 improvements: goals no longer need to be stated as "<prems> ==>
   806 False", equivalences (i.e. "=" on type bool) are handled, variable
   807 names of the form "lit_<n>" are no longer reserved, significant
   808 speedup.
   809 
   810 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   811 zChaff is still supported as well.
   812 
   813 * 'inductive' and 'datatype': provide projections of mutual rules,
   814 bundled as foo_bar.inducts;
   815 
   816 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   817 Library.
   818 
   819 * Library: moved theory Accessible_Part to main HOL.
   820 
   821 * Library: added theory Coinductive_List of potentially infinite lists
   822 as greatest fixed-point.
   823 
   824 * Library: added theory AssocList which implements (finite) maps as
   825 association lists.
   826 
   827 * Added proof method ``evaluation'' for efficiently solving a goal
   828 (i.e. a boolean expression) by compiling it to ML. The goal is
   829 "proved" (via an oracle) if it evaluates to True.
   830 
   831 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   832 also when invoked by the simplifier.  This results in the simplifier
   833 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   834 fast_arith_split_limit to 0 to obtain the old behavior.
   835 
   836 * Support for hex (0x20) and binary (0b1001) numerals.
   837 
   838 * New method: reify eqs (t), where eqs are equations for an
   839 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   840 parameter, computes a term s::'b and a list xs::'a list and proves the
   841 theorem I xs s = t. This is also known as reification or quoting. The
   842 resulting theorem is applied to the subgoal to substitute t with I xs
   843 s.  If t is omitted, the subgoal itself is reified.
   844 
   845 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   846 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   847 where f is supposed to be a computable function (in the sense of code
   848 generattion). The method uses reify to compute s and xs as above then
   849 applies corr_thm and uses normalization by evaluation to "prove" f s =
   850 r and finally gets the theorem t = r, which is again applied to the
   851 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   852 
   853 * Reflection: Automatic refification now handels binding, an example
   854 is available in HOL/ex/ReflectionEx.thy
   855 
   856 
   857 *** HOL-Algebra ***
   858 
   859 * Formalisation of ideals and the quotient construction over rings.
   860 
   861 * Order and lattice theory no longer based on records.
   862 INCOMPATIBILITY.
   863 
   864 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   865 greatest_closed.  INCOMPATIBILITY.
   866 
   867 * Method algebra is now set up via an attribute.  For examples see
   868 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   869 of algebraic structures.
   870 
   871 * Renamed theory CRing to Ring.
   872 
   873 
   874 *** HOL-Complex ***
   875 
   876 * Theory Real: new method ferrack implements quantifier elimination
   877 for linear arithmetic over the reals. The quantifier elimination
   878 feature is used only for decision, for compatibility with arith. This
   879 means a goal is either solved or left unchanged, no simplification.
   880 
   881 * Hyperreal: Functions root and sqrt are now defined on negative real
   882 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   883 Nonnegativity side conditions have been removed from many lemmas, so
   884 that more subgoals may now be solved by simplification; potential
   885 INCOMPATIBILITY.
   886 
   887 * Real: New axiomatic classes formalize real normed vector spaces and
   888 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   889 and norm :: 'a => real.
   890 
   891 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   892 from reals into other types. The overloaded constant Reals :: 'a set
   893 is now defined as range of_real; potential INCOMPATIBILITY.
   894 
   895 * Hyperreal: Several constants that previously worked only for the
   896 reals have been generalized, so they now work over arbitrary vector
   897 spaces. Type annotations may need to be added in some cases; potential
   898 INCOMPATIBILITY.
   899 
   900   Infinitesimal  :: ('a::real_normed_vector) star set
   901   HFinite        :: ('a::real_normed_vector) star set
   902   HInfinite      :: ('a::real_normed_vector) star set
   903   approx         :: ('a::real_normed_vector) star => 'a star => bool
   904   monad          :: ('a::real_normed_vector) star => 'a star set
   905   galaxy         :: ('a::real_normed_vector) star => 'a star set
   906   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   907   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   908   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   909   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   910   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   911   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   912   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   913   sgn            :: 'a::real_normed_vector => 'a
   914 
   915 * Complex: Some complex-specific constants are now abbreviations for
   916 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   917 hnorm.  Other constants have been entirely removed in favor of the
   918 polymorphic versions (INCOMPATIBILITY):
   919 
   920   approx        <-- capprox
   921   HFinite       <-- CFinite
   922   HInfinite     <-- CInfinite
   923   Infinitesimal <-- CInfinitesimal
   924   monad         <-- cmonad
   925   galaxy        <-- cgalaxy
   926   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   927   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   928   (ns)deriv     <-- (ns)cderiv
   929 
   930 
   931 *** ML ***
   932 
   933 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   934 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   935 init only required for impure data.  INCOMPATIBILITY: empty really
   936 need to be empty (no dependencies on theory content!)
   937 
   938 * ML within Isar: antiquotations allow to embed statically-checked
   939 formal entities in the source, referring to the context available at
   940 compile-time.  For example:
   941 
   942 ML {* @{typ "'a => 'b"} *}
   943 ML {* @{term "%x. x"} *}
   944 ML {* @{prop "x == y"} *}
   945 ML {* @{ctyp "'a => 'b"} *}
   946 ML {* @{cterm "%x. x"} *}
   947 ML {* @{cprop "x == y"} *}
   948 ML {* @{thm asm_rl} *}
   949 ML {* @{thms asm_rl} *}
   950 ML {* @{const_name c} *}
   951 ML {* @{const_syntax c} *}
   952 ML {* @{context} *}
   953 ML {* @{theory} *}
   954 ML {* @{theory Pure} *}
   955 ML {* @{simpset} *}
   956 ML {* @{claset} *}
   957 ML {* @{clasimpset} *}
   958 
   959 The same works for sources being ``used'' within an Isar context.
   960 
   961 * ML in Isar: improved error reporting; extra verbosity with
   962 Toplevel.debug enabled.
   963 
   964 * Pure/library:
   965 
   966   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   967   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   968 
   969 The semantics of "burrow" is: "take a function with *simulatanously*
   970 transforms a list of value, and apply it *simulatanously* to a list of
   971 list of values of the appropriate type". Compare this with "map" which
   972 would *not* apply its argument function simulatanously but in
   973 sequence; "fold_burrow" has an additional context.
   974 
   975 * Pure/library: functions map2 and fold2 with curried syntax for
   976 simultanous mapping and folding:
   977 
   978     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   979     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   980 
   981 * Pure/library: indexed lists - some functions in the Isabelle library
   982 treating lists over 'a as finite mappings from [0...n] to 'a have been
   983 given more convenient names and signatures reminiscent of similar
   984 functions for alists, tables, etc:
   985 
   986   val nth: 'a list -> int -> 'a 
   987   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   988   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   989 
   990 Note that fold_index starts counting at index 0, not 1 like foldln
   991 used to.
   992 
   993 * Pure/library: added general ``divide_and_conquer'' combinator on
   994 lists.
   995 
   996 * Pure/General/table.ML: the join operations now works via exceptions
   997 DUP/SAME instead of type option.  This is simpler in simple cases, and
   998 admits slightly more efficient complex applications.
   999 
  1000 * Pure: datatype Context.generic joins theory/Proof.context and
  1001 provides some facilities for code that works in either kind of
  1002 context, notably GenericDataFun for uniform theory and proof data.
  1003 
  1004 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1005 use Context.generic instead of just theory.
  1006 
  1007 * Pure: simplified internal attribute type, which is now always
  1008 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1009 vs. local (Proof.context) attributes have been discontinued, while
  1010 minimizing code duplication.  Thm.rule_attribute and
  1011 Thm.declaration_attribute build canonical attributes; see also
  1012 structure Context for further operations on Context.generic, notably
  1013 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1014 declarations and definitions.
  1015 
  1016 * Pure/kernel: consts certification ignores sort constraints given in
  1017 signature declarations.  (This information is not relevant to the
  1018 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1019 potential INCOMPATIBILITY.
  1020 
  1021 * Pure: axiomatic type classes are now purely definitional, with
  1022 explicit proofs of class axioms and super class relations performed
  1023 internally.  See Pure/axclass.ML for the main internal interfaces --
  1024 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1025 AxClass.axiomatize_class/classrel/arity supercede
  1026 Sign.add_classes/classrel/arities.
  1027 
  1028 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1029 global/local versions on theory vs. Proof.context have been
  1030 discontinued; Attrib.syntax and Method.syntax have been adapted
  1031 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1032 attributes, methods, etc.
  1033 
  1034 * Pure: several functions of signature "... -> theory -> theory * ..."
  1035 have been reoriented to "... -> theory -> ... * theory" in order to
  1036 allow natural usage in combination with the ||>, ||>>, |-> and
  1037 fold_map combinators.
  1038 
  1039 * Pure: official theorem names (closed derivations) and additional
  1040 comments (tags) are now strictly separate.  Name hints -- which are
  1041 maintained as tags -- may be attached any time without affecting the
  1042 derivation.
  1043 
  1044 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1045 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1046 achieve the old behaviour.
  1047 
  1048 * Pure: the "Goal" constant is now called "prop", supporting a
  1049 slightly more general idea of ``protecting'' meta-level rule
  1050 statements.
  1051 
  1052 * Pure: Logic.(un)varify only works in a global context, which is now
  1053 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1054 Logic.legacy_(un)varify as temporary workaround.
  1055 
  1056 * Pure: structure Name provides scalable operations for generating
  1057 internal variable names, notably Name.variants etc.  This replaces
  1058 some popular functions from term.ML:
  1059 
  1060   Term.variant		->  Name.variant
  1061   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1062   Term.invent_names	->  Name.invent_list
  1063 
  1064 Note that low-level renaming rarely occurs in new code -- operations
  1065 from structure Variable are used instead (see below).
  1066 
  1067 * Pure: structure Variable provides fundamental operations for proper
  1068 treatment of fixed/schematic variables in a context.  For example,
  1069 Variable.import introduces fixes for schematics of given facts and
  1070 Variable.export reverses the effect (up to renaming) -- this replaces
  1071 various freeze_thaw operations.
  1072 
  1073 * Pure: structure Goal provides simple interfaces for
  1074 init/conclude/finish and tactical prove operations (replacing former
  1075 Tactic.prove).  Goal.prove is the canonical way to prove results
  1076 within a given context; Goal.prove_global is a degraded version for
  1077 theory level goals, including a global Drule.standard.  Note that
  1078 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1079 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1080 in a locale context).
  1081 
  1082 * Isar: simplified treatment of user-level errors, using exception
  1083 ERROR of string uniformly.  Function error now merely raises ERROR,
  1084 without any side effect on output channels.  The Isar toplevel takes
  1085 care of proper display of ERROR exceptions.  ML code may use plain
  1086 handle/can/try; cat_error may be used to concatenate errors like this:
  1087 
  1088   ... handle ERROR msg => cat_error msg "..."
  1089 
  1090 Toplevel ML code (run directly or through the Isar toplevel) may be
  1091 embedded into the Isar toplevel with exception display/debug like
  1092 this:
  1093 
  1094   Isar.toplevel (fn () => ...)
  1095 
  1096 INCOMPATIBILITY, removed special transform_error facilities, removed
  1097 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1098 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1099 -- use plain ERROR instead.
  1100 
  1101 * Isar: theory setup now has type (theory -> theory), instead of a
  1102 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1103 
  1104 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1105 subject to ProofContext.debug/verbose flags.
  1106 
  1107 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1108 theory before entering a proof state.  Transactions now always see a
  1109 quasi-functional intermediate checkpoint, both in interactive and
  1110 batch mode.
  1111 
  1112 * Simplifier: the simpset of a running simplification process now
  1113 contains a proof context (cf. Simplifier.the_context), which is the
  1114 very context that the initial simpset has been retrieved from (by
  1115 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1116 (solver, looper etc.) may depend on arbitrary proof data.
  1117 
  1118 * Simplifier.inherit_context inherits the proof context (plus the
  1119 local bounds) of the current simplification process; any simproc
  1120 etc. that calls the Simplifier recursively should do this!  Removed
  1121 former Simplifier.inherit_bounds, which is already included here --
  1122 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1123 specify an explicit context using Simplifier.context/theory_context.
  1124 
  1125 * Simplifier/Classical Reasoner: more abstract interfaces
  1126 change_simpset/claset for modifying the simpset/claset reference of a
  1127 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1128 INCOMPATIBILITY.
  1129 
  1130 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1131 "Trueprop" etc.
  1132 
  1133 
  1134 *** System ***
  1135 
  1136 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1137 locations -- now includes the Isabelle version identifier as well.
  1138 This simplifies use of multiple Isabelle installations.
  1139 
  1140 * isabelle-process: option -S (secure mode) disables some critical
  1141 operations, notably runtime compilation and evaluation of ML source
  1142 code.
  1143 
  1144 
  1145 New in Isabelle2005 (October 2005)
  1146 ----------------------------------
  1147 
  1148 *** General ***
  1149 
  1150 * Theory headers: the new header syntax for Isar theories is
  1151 
  1152   theory <name>
  1153   imports <theory1> ... <theoryN>
  1154   uses <file1> ... <fileM>
  1155   begin
  1156 
  1157 where the 'uses' part is optional.  The previous syntax
  1158 
  1159   theory <name> = <theory1> + ... + <theoryN>:
  1160 
  1161 will disappear in the next release.  Use isatool fixheaders to convert
  1162 existing theory files.  Note that there is no change in ancient
  1163 non-Isar theories now, but these will disappear soon.
  1164 
  1165 * Theory loader: parent theories can now also be referred to via
  1166 relative and absolute paths.
  1167 
  1168 * Command 'find_theorems' searches for a list of criteria instead of a
  1169 list of constants. Known criteria are: intro, elim, dest, name:string,
  1170 simp:term, and any term. Criteria can be preceded by '-' to select
  1171 theorems that do not match. Intro, elim, dest select theorems that
  1172 match the current goal, name:s selects theorems whose fully qualified
  1173 name contain s, and simp:term selects all simplification rules whose
  1174 lhs match term.  Any other term is interpreted as pattern and selects
  1175 all theorems matching the pattern. Available in ProofGeneral under
  1176 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1177 
  1178   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1179 
  1180 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1181 matching the current goal as introduction rule and not having "HOL."
  1182 in their name (i.e. not being defined in theory HOL).
  1183 
  1184 * Command 'thms_containing' has been discontinued in favour of
  1185 'find_theorems'; INCOMPATIBILITY.
  1186 
  1187 * Communication with Proof General is now 8bit clean, which means that
  1188 Unicode text in UTF-8 encoding may be used within theory texts (both
  1189 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1190 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1191 
  1192   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1193   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1194 
  1195 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1196 Classical Reasoner.  Typical big applications run around 2 times
  1197 faster.
  1198 
  1199 
  1200 *** Document preparation ***
  1201 
  1202 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1203 of raw sources.  Only those symbols that do not require additional
  1204 LaTeX packages (depending on comments in isabellesym.sty) are
  1205 displayed properly, everything else is left verbatim.  isatool display
  1206 and isatool print are used as front ends (these are subject to the
  1207 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1208 
  1209 * Command tags control specific markup of certain regions of text,
  1210 notably folding and hiding.  Predefined tags include "theory" (for
  1211 theory begin and end), "proof" for proof commands, and "ML" for
  1212 commands involving ML code; the additional tags "visible" and
  1213 "invisible" are unused by default.  Users may give explicit tag
  1214 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1215 interpretation of tags is determined by the LaTeX job during document
  1216 preparation: see option -V of isatool usedir, or options -n and -t of
  1217 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1218 \isadroptag.
  1219 
  1220 Several document versions may be produced at the same time via isatool
  1221 usedir (the generated index.html will link all of them).  Typical
  1222 specifications include ''-V document=theory,proof,ML'' to present
  1223 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1224 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1225 these parts without any formal replacement text.  The Isabelle site
  1226 default settings produce ''document'' and ''outline'' versions as
  1227 specified above.
  1228 
  1229 * Several new antiquotations:
  1230 
  1231   @{term_type term} prints a term with its type annotated;
  1232 
  1233   @{typeof term} prints the type of a term;
  1234 
  1235   @{const const} is the same as @{term const}, but checks that the
  1236   argument is a known logical constant;
  1237 
  1238   @{term_style style term} and @{thm_style style thm} print a term or
  1239   theorem applying a "style" to it
  1240 
  1241   @{ML text}
  1242 
  1243 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1244 definitions, equations, inequations etc., 'concl' printing only the
  1245 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1246 to print the specified premise.  TermStyle.add_style provides an ML
  1247 interface for introducing further styles.  See also the "LaTeX Sugar"
  1248 document practical applications.  The ML antiquotation prints
  1249 type-checked ML expressions verbatim.
  1250 
  1251 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1252 and 'text' support optional locale specification '(in loc)', which
  1253 specifies the default context for interpreting antiquotations.  For
  1254 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1255 
  1256 * Option 'locale=NAME' of antiquotations specifies an alternative
  1257 context interpreting the subsequent argument.  For example: @{thm
  1258 [locale=lattice] inf_assoc}.
  1259 
  1260 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1261 a proof context.
  1262 
  1263 * Proper output of antiquotations for theory commands involving a
  1264 proof context (such as 'locale' or 'theorem (in loc) ...').
  1265 
  1266 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1267 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1268 
  1269 * isatool usedir: new option -C (default true) controls whether option
  1270 -D should include a copy of the original document directory; -C false
  1271 prevents unwanted effects such as copying of administrative CVS data.
  1272 
  1273 
  1274 *** Pure ***
  1275 
  1276 * Considerably improved version of 'constdefs' command.  Now performs
  1277 automatic type-inference of declared constants; additional support for
  1278 local structure declarations (cf. locales and HOL records), see also
  1279 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1280 sequential dependencies of definitions within a single 'constdefs'
  1281 section; moreover, the declared name needs to be an identifier.  If
  1282 all fails, consider to fall back on 'consts' and 'defs' separately.
  1283 
  1284 * Improved indexed syntax and implicit structures.  First of all,
  1285 indexed syntax provides a notational device for subscripted
  1286 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1287 expressions.  Secondly, in a local context with structure
  1288 declarations, number indexes \<^sub>n or the empty index (default
  1289 number 1) refer to a certain fixed variable implicitly; option
  1290 show_structs controls printing of implicit structures.  Typical
  1291 applications of these concepts involve record types and locales.
  1292 
  1293 * New command 'no_syntax' removes grammar declarations (and
  1294 translations) resulting from the given syntax specification, which is
  1295 interpreted in the same manner as for the 'syntax' command.
  1296 
  1297 * 'Advanced' translation functions (parse_translation etc.) may depend
  1298 on the signature of the theory context being presently used for
  1299 parsing/printing, see also isar-ref manual.
  1300 
  1301 * Improved 'oracle' command provides a type-safe interface to turn an
  1302 ML expression of type theory -> T -> term into a primitive rule of
  1303 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1304 is already included here); see also FOL/ex/IffExample.thy;
  1305 INCOMPATIBILITY.
  1306 
  1307 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1308 before); "cI" is no longer bound, use "c.intro" instead.
  1309 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1310 axclasses vs. locales.
  1311 
  1312 * Improved internal renaming of symbolic identifiers -- attach primes
  1313 instead of base 26 numbers.
  1314 
  1315 * New flag show_question_marks controls printing of leading question
  1316 marks in schematic variable names.
  1317 
  1318 * In schematic variable names, *any* symbol following \<^isub> or
  1319 \<^isup> is now treated as part of the base name.  For example, the
  1320 following works without printing of awkward ".0" indexes:
  1321 
  1322   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1323     by simp
  1324 
  1325 * Inner syntax includes (*(*nested*) comments*).
  1326 
  1327 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1328 annotations as "(00...)".
  1329 
  1330 * Clear separation of logical types and nonterminals, where the latter
  1331 may only occur in 'syntax' specifications or type abbreviations.
  1332 Before that distinction was only partially implemented via type class
  1333 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1334 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1335 exotic syntax specifications may require further adaption
  1336 (e.g. Cube/Cube.thy).
  1337 
  1338 * Removed obsolete type class "logic", use the top sort {} instead.
  1339 Note that non-logical types should be declared as 'nonterminals'
  1340 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1341 specifications.
  1342 
  1343 * Attributes 'induct' and 'cases': type or set names may now be
  1344 locally fixed variables as well.
  1345 
  1346 * Simplifier: can now control the depth to which conditional rewriting
  1347 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1348 Limit.
  1349 
  1350 * Simplifier: simplification procedures may now take the current
  1351 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1352 interface), which is very useful for calling the Simplifier
  1353 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1354 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1355 low-level mk_simproc no longer applies Logic.varify internally, to
  1356 allow for use in a context of fixed variables.
  1357 
  1358 * thin_tac now works even if the assumption being deleted contains !!
  1359 or ==>.  More generally, erule now works even if the major premise of
  1360 the elimination rule contains !! or ==>.
  1361 
  1362 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1363 
  1364 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1365 from Pure, which contains all common declarations already.  Both
  1366 theories are defined via plain Isabelle/Isar .thy files.
  1367 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1368 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1369 use isatool fixcpure to adapt your theory and ML sources.
  1370 
  1371 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1372 selections of theorems in named facts via index ranges.
  1373 
  1374 * 'print_theorems': in theory mode, really print the difference
  1375 wrt. the last state (works for interactive theory development only),
  1376 in proof mode print all local facts (cf. 'print_facts');
  1377 
  1378 * 'hide': option '(open)' hides only base names.
  1379 
  1380 * More efficient treatment of intermediate checkpoints in interactive
  1381 theory development.
  1382 
  1383 * Code generator is now invoked via code_module (incremental code
  1384 generation) and code_library (modular code generation, ML structures
  1385 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1386 must be quoted when used as identifiers.
  1387 
  1388 * New 'value' command for reading, evaluating and printing terms using
  1389 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1390 quoted when used as identifier.
  1391 
  1392 
  1393 *** Locales ***
  1394 
  1395 * New commands for the interpretation of locale expressions in
  1396 theories (1), locales (2) and proof contexts (3).  These generate
  1397 proof obligations from the expression specification.  After the
  1398 obligations have been discharged, theorems of the expression are added
  1399 to the theory, target locale or proof context.  The synopsis of the
  1400 commands is a follows:
  1401 
  1402   (1) interpretation expr inst
  1403   (2) interpretation target < expr
  1404   (3) interpret expr inst
  1405 
  1406 Interpretation in theories and proof contexts require a parameter
  1407 instantiation of terms from the current context.  This is applied to
  1408 specifications and theorems of the interpreted expression.
  1409 Interpretation in locales only permits parameter renaming through the
  1410 locale expression.  Interpretation is smart in that interpretations
  1411 that are active already do not occur in proof obligations, neither are
  1412 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1413 inspect active interpretations of a particular locale.  For details,
  1414 see the Isar Reference manual.  Examples can be found in
  1415 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1416 
  1417 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1418 'interpret' instead.
  1419 
  1420 * New context element 'constrains' for adding type constraints to
  1421 parameters.
  1422 
  1423 * Context expressions: renaming of parameters with syntax
  1424 redeclaration.
  1425 
  1426 * Locale declaration: 'includes' disallowed.
  1427 
  1428 * Proper static binding of attribute syntax -- i.e. types / terms /
  1429 facts mentioned as arguments are always those of the locale definition
  1430 context, independently of the context of later invocations.  Moreover,
  1431 locale operations (renaming and type / term instantiation) are applied
  1432 to attribute arguments as expected.
  1433 
  1434 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1435 actual attributes; rare situations may require Attrib.attribute to
  1436 embed those attributes into Attrib.src that lack concrete syntax.
  1437 Attribute implementations need to cooperate properly with the static
  1438 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1439 Attrib.XXX_thm etc. already do the right thing without further
  1440 intervention.  Only unusual applications -- such as "where" or "of"
  1441 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1442 on the context and the facts involved -- may have to assign parsed
  1443 values to argument tokens explicitly.
  1444 
  1445 * Changed parameter management in theorem generation for long goal
  1446 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1447 theorem statement in rare situations.
  1448 
  1449 * Locale inspection command 'print_locale' omits notes elements.  Use
  1450 'print_locale!' to have them included in the output.
  1451 
  1452 
  1453 *** Provers ***
  1454 
  1455 * Provers/hypsubst.ML: improved version of the subst method, for
  1456 single-step rewriting: it now works in bound variable contexts. New is
  1457 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1458 rewrite a different subterm than the original subst method, which is
  1459 still available as 'simplesubst'.
  1460 
  1461 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1462 and quasi orders.
  1463 
  1464 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1465 reflexive-transitive closure of relations.
  1466 
  1467 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1468 limit (previously hard-coded with a value of 20) user-definable.
  1469 
  1470 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1471 is peformed already.  Object-logics merely need to finish their
  1472 initial simpset configuration as before.  INCOMPATIBILITY.
  1473 
  1474 
  1475 *** HOL ***
  1476 
  1477 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1478 
  1479   syntax (epsilon)
  1480     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1481 
  1482 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1483 and x-symbol; use option '-m epsilon' to get it actually printed.
  1484 Moreover, the mathematically important symbolic identifier \<epsilon>
  1485 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1486 
  1487 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1488 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1489 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1490 support corresponding Isar calculations.
  1491 
  1492 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1493 instead of ":".
  1494 
  1495 * theory SetInterval: changed the syntax for open intervals:
  1496 
  1497   Old       New
  1498   {..n(}    {..<n}
  1499   {)n..}    {n<..}
  1500   {m..n(}   {m..<n}
  1501   {)m..n}   {m<..n}
  1502   {)m..n(}  {m<..<n}
  1503 
  1504 The old syntax is still supported but will disappear in the next
  1505 release.  For conversion use the following Emacs search and replace
  1506 patterns (these are not perfect but work quite well):
  1507 
  1508   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1509   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1510 
  1511 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1512 equalities in commutative rings; method 'algebra' provides a generic
  1513 interface.
  1514 
  1515 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1516 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1517 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1518 be a tuple pattern.
  1519 
  1520 Some new syntax forms are available:
  1521 
  1522   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1523   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1524   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1525   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1526 
  1527 The latter form "\<Sum>x < k. e" used to be based on a separate
  1528 function "Summation", which has been discontinued.
  1529 
  1530 * theory Finite_Set: in structured induction proofs, the insert case
  1531 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1532 (insert F x)'.
  1533 
  1534 * The 'refute' command has been extended to support a much larger
  1535 fragment of HOL, including axiomatic type classes, constdefs and
  1536 typedefs, inductive datatypes and recursion.
  1537 
  1538 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1539 Requires zChaff with proof generation to be installed.  See
  1540 HOL/ex/SAT_Examples.thy for examples.
  1541 
  1542 * Datatype induction via method 'induct' now preserves the name of the
  1543 induction variable. For example, when proving P(xs::'a list) by
  1544 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1545 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1546 in unstructured proof scripts.
  1547 
  1548 * Reworked implementation of records.  Improved scalability for
  1549 records with many fields, avoiding performance problems for type
  1550 inference. Records are no longer composed of nested field types, but
  1551 of nested extension types. Therefore the record type only grows linear
  1552 in the number of extensions and not in the number of fields.  The
  1553 top-level (users) view on records is preserved.  Potential
  1554 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1555 old record representation. The type generated for a record is called
  1556 <record_name>_ext_type.
  1557 
  1558 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1559 proofs triggered by a record definition or a simproc (if
  1560 quick_and_dirty is enabled).  Definitions of large records can take
  1561 quite long.
  1562 
  1563 New simproc record_upd_simproc for simplification of multiple record
  1564 updates enabled by default.  Moreover, trivial updates are also
  1565 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1566 occasionally, since simplification is more powerful by default.
  1567 
  1568 * typedef: proper support for polymorphic sets, which contain extra
  1569 type-variables in the term.
  1570 
  1571 * Simplifier: automatically reasons about transitivity chains
  1572 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1573 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1574 old proofs break occasionally as simplification may now solve more
  1575 goals than previously.
  1576 
  1577 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1578 present.  Works for all partial orders (class "order"), in particular
  1579 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1580 just like y <= x.
  1581 
  1582 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1583 bound variable or a constant then the let is unfolded.  Otherwise
  1584 first a is simplified to b, and then f b is simplified to g. If
  1585 possible we abstract b from g arriving at "let x = b in h x",
  1586 otherwise we unfold the let and arrive at g.  The simproc can be
  1587 enabled/disabled by the reference use_let_simproc.  Potential
  1588 INCOMPATIBILITY since simplification is more powerful by default.
  1589 
  1590 * Classical reasoning: the meson method now accepts theorems as arguments.
  1591 
  1592 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1593 jobs to provide advice on the provability of subgoals.
  1594 
  1595 * Theory OrderedGroup and Ring_and_Field: various additions and
  1596 improvements to faciliate calculations involving equalities and
  1597 inequalities.
  1598 
  1599 The following theorems have been eliminated or modified
  1600 (INCOMPATIBILITY):
  1601 
  1602   abs_eq             now named abs_of_nonneg
  1603   abs_of_ge_0        now named abs_of_nonneg
  1604   abs_minus_eq       now named abs_of_nonpos
  1605   imp_abs_id         now named abs_of_nonneg
  1606   imp_abs_neg_id     now named abs_of_nonpos
  1607   mult_pos           now named mult_pos_pos
  1608   mult_pos_le        now named mult_nonneg_nonneg
  1609   mult_pos_neg_le    now named mult_nonneg_nonpos
  1610   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1611   mult_neg           now named mult_neg_neg
  1612   mult_neg_le        now named mult_nonpos_nonpos
  1613 
  1614 * Theory Parity: added rules for simplifying exponents.
  1615 
  1616 * Theory List:
  1617 
  1618 The following theorems have been eliminated or modified
  1619 (INCOMPATIBILITY):
  1620 
  1621   list_all_Nil       now named list_all.simps(1)
  1622   list_all_Cons      now named list_all.simps(2)
  1623   list_all_conv      now named list_all_iff
  1624   set_mem_eq         now named mem_iff
  1625 
  1626 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1627 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1628 
  1629 
  1630 *** HOL-Complex ***
  1631 
  1632 * Theory RealDef: better support for embedding natural numbers and
  1633 integers in the reals.
  1634 
  1635 The following theorems have been eliminated or modified
  1636 (INCOMPATIBILITY):
  1637 
  1638   exp_ge_add_one_self  now requires no hypotheses
  1639   real_of_int_add      reversed direction of equality (use [symmetric])
  1640   real_of_int_minus    reversed direction of equality (use [symmetric])
  1641   real_of_int_diff     reversed direction of equality (use [symmetric])
  1642   real_of_int_mult     reversed direction of equality (use [symmetric])
  1643 
  1644 * Theory RComplete: expanded support for floor and ceiling functions.
  1645 
  1646 * Theory Ln is new, with properties of the natural logarithm
  1647 
  1648 * Hyperreal: There is a new type constructor "star" for making
  1649 nonstandard types.  The old type names are now type synonyms:
  1650 
  1651   hypreal = real star
  1652   hypnat = nat star
  1653   hcomplex = complex star
  1654 
  1655 * Hyperreal: Many groups of similarly-defined constants have been
  1656 replaced by polymorphic versions (INCOMPATIBILITY):
  1657 
  1658   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1659 
  1660   starset      <-- starsetNat, starsetC
  1661   *s*          <-- *sNat*, *sc*
  1662   starset_n    <-- starsetNat_n, starsetC_n
  1663   *sn*         <-- *sNatn*, *scn*
  1664   InternalSets <-- InternalNatSets, InternalCSets
  1665 
  1666   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1667   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1668   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1669   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1670   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1671 
  1672 * Hyperreal: Many type-specific theorems have been removed in favor of
  1673 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1674 
  1675   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1676   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1677   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1678   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1679   right_minus <-- hypreal_add_minus
  1680   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1681   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1682   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1683   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1684   mult_1_right <-- hcomplex_mult_one_right
  1685   mult_zero_left <-- hcomplex_mult_zero_left
  1686   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1687   right_distrib <-- hypnat_add_mult_distrib2
  1688   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1689   right_inverse <-- hypreal_mult_inverse
  1690   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1691   order_refl <-- {hypreal,hypnat}_le_refl
  1692   order_trans <-- {hypreal,hypnat}_le_trans
  1693   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1694   order_less_le <-- {hypreal,hypnat}_less_le
  1695   linorder_linear <-- {hypreal,hypnat}_le_linear
  1696   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1697   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1698   add_nonneg_nonneg <-- hypreal_le_add_order
  1699 
  1700 * Hyperreal: Separate theorems having to do with type-specific
  1701 versions of constants have been merged into theorems that apply to the
  1702 new polymorphic constants (INCOMPATIBILITY):
  1703 
  1704   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1705   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1706   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1707   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1708   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1709   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1710   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1711   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1712   STAR_diff <-- {STAR,STARC}_diff
  1713   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1714     STARC_hcomplex_of_complex}_image_subset
  1715   starset_n_Un <-- starset{Nat,C}_n_Un
  1716   starset_n_Int <-- starset{Nat,C}_n_Int
  1717   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1718   starset_n_diff <-- starset{Nat,C}_n_diff
  1719   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1720   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1721   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1722   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1723   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1724   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1725   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1726   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1727   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1728   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1729   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1730   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1731   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1732   starfun_diff <-- starfun{C,RC,CR}_diff
  1733   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1734   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1735   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1736   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1737   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1738   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1739   starfun_Id <-- starfunC_Id
  1740   starfun_approx <-- starfun{Nat,CR}_approx
  1741   starfun_capprox <-- starfun{C,RC}_capprox
  1742   starfun_abs <-- starfunNat_rabs
  1743   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1744   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1745   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1746   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1747   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1748   starfun_add_approx <-- starfunCR_add_approx
  1749   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1750   starfun_divide <-- starfun{C,CR,RC}_divide
  1751   starfun_n <-- starfun{Nat,C}_n
  1752   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1753   starfun_n_add <-- starfun{Nat,C}_n_add
  1754   starfun_n_add_minus <-- starfunNat_n_add_minus
  1755   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1756   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1757   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1758 
  1759   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1760   star_n_minus <-- {hypreal,hcomplex}_minus
  1761   star_n_diff <-- {hypreal,hcomplex}_diff
  1762   star_n_mult <-- {hypreal,hcomplex}_mult
  1763   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1764   star_n_le <-- {hypreal,hypnat}_le
  1765   star_n_less <-- {hypreal,hypnat}_less
  1766   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1767   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1768   star_n_abs <-- hypreal_hrabs
  1769   star_n_divide <-- hcomplex_divide
  1770 
  1771   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1772   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1773   star_of_diff <-- hypreal_of_real_diff
  1774   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1775   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1776   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1777   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1778   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1779   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1780   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1781   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1782   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1783   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1784   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1785   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1786   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1787   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1788   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1789   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1790   star_of_power <-- hypreal_of_real_power
  1791   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1792 
  1793 * Hyperreal: new method "transfer" that implements the transfer
  1794 principle of nonstandard analysis. With a subgoal that mentions
  1795 nonstandard types like "'a star", the command "apply transfer"
  1796 replaces it with an equivalent one that mentions only standard types.
  1797 To be successful, all free variables must have standard types; non-
  1798 standard variables must have explicit universal quantifiers.
  1799 
  1800 * Hyperreal: A theory of Taylor series.
  1801 
  1802 
  1803 *** HOLCF ***
  1804 
  1805 * Discontinued special version of 'constdefs' (which used to support
  1806 continuous functions) in favor of the general Pure one with full
  1807 type-inference.
  1808 
  1809 * New simplification procedure for solving continuity conditions; it
  1810 is much faster on terms with many nested lambda abstractions (cubic
  1811 instead of exponential time).
  1812 
  1813 * New syntax for domain package: selector names are now optional.
  1814 Parentheses should be omitted unless argument is lazy, for example:
  1815 
  1816   domain 'a stream = cons "'a" (lazy "'a stream")
  1817 
  1818 * New command 'fixrec' for defining recursive functions with pattern
  1819 matching; defining multiple functions with mutual recursion is also
  1820 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1821 sinr, or any data constructor defined by the domain package. The given
  1822 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1823 syntax and examples.
  1824 
  1825 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1826 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1827 but the proof obligation additionally includes an admissibility
  1828 requirement. The packages generate instances of class cpo or pcpo,
  1829 with continuity and strictness theorems for Rep and Abs.
  1830 
  1831 * HOLCF: Many theorems have been renamed according to a more standard naming
  1832 scheme (INCOMPATIBILITY):
  1833 
  1834   foo_inject:  "foo$x = foo$y ==> x = y"
  1835   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1836   foo_less:    "(foo$x << foo$y) = (x << y)"
  1837   foo_strict:  "foo$UU = UU"
  1838   foo_defined: "... ==> foo$x ~= UU"
  1839   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1840 
  1841 
  1842 *** ZF ***
  1843 
  1844 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1845 including the First Isomorphism Theorem (on quotienting by the kernel
  1846 of a homomorphism).
  1847 
  1848 * ZF/Simplifier: install second copy of type solver that actually
  1849 makes use of TC rules declared to Isar proof contexts (or locales);
  1850 the old version is still required for ML proof scripts.
  1851 
  1852 
  1853 *** Cube ***
  1854 
  1855 * Converted to Isar theory format; use locales instead of axiomatic
  1856 theories.
  1857 
  1858 
  1859 *** ML ***
  1860 
  1861 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1862 for ||>, ||>>, |>>,
  1863 
  1864 * Pure/library.ML no longer defines its own option datatype, but uses
  1865 that of the SML basis, which has constructors NONE and SOME instead of
  1866 None and Some, as well as exception Option.Option instead of OPTION.
  1867 The functions the, if_none, is_some, is_none have been adapted
  1868 accordingly, while Option.map replaces apsome.
  1869 
  1870 * Pure/library.ML: the exception LIST has been given up in favour of
  1871 the standard exceptions Empty and Subscript, as well as
  1872 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1873 superceded by the standard hd and tl functions etc.
  1874 
  1875 A number of basic list functions are no longer exported to the ML
  1876 toplevel, as they are variants of predefined functions.  The following
  1877 suggests how one can translate existing code:
  1878 
  1879     rev_append xs ys = List.revAppend (xs, ys)
  1880     nth_elem (i, xs) = List.nth (xs, i)
  1881     last_elem xs = List.last xs
  1882     flat xss = List.concat xss
  1883     seq fs = List.app fs
  1884     partition P xs = List.partition P xs
  1885     mapfilter f xs = List.mapPartial f xs
  1886 
  1887 * Pure/library.ML: several combinators for linear functional
  1888 transformations, notably reverse application and composition:
  1889 
  1890   x |> f                f #> g
  1891   (x, y) |-> f          f #-> g
  1892 
  1893 * Pure/library.ML: introduced/changed precedence of infix operators:
  1894 
  1895   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1896   infix 2 ?;
  1897   infix 3 o oo ooo oooo;
  1898   infix 4 ~~ upto downto;
  1899 
  1900 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1901 infix operators.
  1902 
  1903 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1904 fold_map support linear functional transformations and nesting.  For
  1905 example:
  1906 
  1907   fold f [x1, ..., xN] y =
  1908     y |> f x1 |> ... |> f xN
  1909 
  1910   (fold o fold) f [xs1, ..., xsN] y =
  1911     y |> fold f xs1 |> ... |> fold f xsN
  1912 
  1913   fold f [x1, ..., xN] =
  1914     f x1 #> ... #> f xN
  1915 
  1916   (fold o fold) f [xs1, ..., xsN] =
  1917     fold f xs1 #> ... #> fold f xsN
  1918 
  1919 * Pure/library.ML: the following selectors on type 'a option are
  1920 available:
  1921 
  1922   the:               'a option -> 'a  (*partial*)
  1923   these:             'a option -> 'a  where 'a = 'b list
  1924   the_default: 'a -> 'a option -> 'a
  1925   the_list:          'a option -> 'a list
  1926 
  1927 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1928 basic operations for association lists, following natural argument
  1929 order; moreover the explicit equality predicate passed here avoids
  1930 potentially expensive polymorphic runtime equality checks.
  1931 The old functions may be expressed as follows:
  1932 
  1933   assoc = uncurry (AList.lookup (op =))
  1934   assocs = these oo AList.lookup (op =)
  1935   overwrite = uncurry (AList.update (op =)) o swap
  1936 
  1937 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1938 
  1939   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1940   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1941 
  1942 replacing make_keylist and keyfilter (occassionally used)
  1943 Naive rewrites:
  1944 
  1945   make_keylist = AList.make
  1946   keyfilter = AList.find (op =)
  1947 
  1948 * eq_fst and eq_snd now take explicit equality parameter, thus
  1949   avoiding eqtypes. Naive rewrites:
  1950 
  1951     eq_fst = eq_fst (op =)
  1952     eq_snd = eq_snd (op =)
  1953 
  1954 * Removed deprecated apl and apr (rarely used).
  1955   Naive rewrites:
  1956 
  1957     apl (n, op) =>>= curry op n
  1958     apr (op, m) =>>= fn n => op (n, m)
  1959 
  1960 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1961 provides a reasonably efficient light-weight implementation of sets as
  1962 lists.
  1963 
  1964 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1965 few new operations; existing lookup and update are now curried to
  1966 follow natural argument order (for use with fold etc.);
  1967 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1968 
  1969 * Pure/General: output via the Isabelle channels of
  1970 writeln/warning/error etc. is now passed through Output.output, with a
  1971 hook for arbitrary transformations depending on the print_mode
  1972 (cf. Output.add_mode -- the first active mode that provides a output
  1973 function wins).  Already formatted output may be embedded into further
  1974 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1975 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1976 accommodate easy composition of diagnostic messages etc.  Programmers
  1977 rarely need to care about Output.output or Output.raw at all, with
  1978 some notable exceptions: Output.output is required when bypassing the
  1979 standard channels (writeln etc.), or in token translations to produce
  1980 properly formatted results; Output.raw is required when capturing
  1981 already output material that will eventually be presented to the user
  1982 a second time.  For the default print mode, both Output.output and
  1983 Output.raw have no effect.
  1984 
  1985 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1986 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1987 cumulative results are displayed at the end of a batch session.
  1988 
  1989 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1990 replaced by File.platform_path and File.shell_path (with appropriate
  1991 hooks).  This provides a clean interface for unusual systems where the
  1992 internal and external process view of file names are different.
  1993 
  1994 * Pure: more efficient orders for basic syntactic entities: added
  1995 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1996 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1997 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1998 orders now -- potential INCOMPATIBILITY for code that depends on a
  1999 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2000 Library.sort_strings on result).
  2001 
  2002 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2003 fold_types traverse types/terms from left to right, observing natural
  2004 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2005 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2006 
  2007 * Pure: name spaces have been refined, with significant changes of the
  2008 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2009 to extern(_table).  The plain name entry path is superceded by a
  2010 general 'naming' context, which also includes the 'policy' to produce
  2011 a fully qualified name and external accesses of a fully qualified
  2012 name; NameSpace.extend is superceded by context dependent
  2013 Sign.declare_name.  Several theory and proof context operations modify
  2014 the naming context.  Especially note Theory.restore_naming and
  2015 ProofContext.restore_naming to get back to a sane state; note that
  2016 Theory.add_path is no longer sufficient to recover from
  2017 Theory.absolute_path in particular.
  2018 
  2019 * Pure: new flags short_names (default false) and unique_names
  2020 (default true) for controlling output of qualified names.  If
  2021 short_names is set, names are printed unqualified.  If unique_names is
  2022 reset, the name prefix is reduced to the minimum required to achieve
  2023 the original result when interning again, even if there is an overlap
  2024 with earlier declarations.
  2025 
  2026 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2027 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2028 (useful for printing error messages).  INCOMPATIBILITY.
  2029 
  2030 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2031 Theory.theory are now identified, referring to the universal
  2032 Context.theory (see Pure/context.ML).  Actual signature and theory
  2033 content is managed as theory data.  The old code and interfaces were
  2034 spread over many files and structures; the new arrangement introduces
  2035 considerable INCOMPATIBILITY to gain more clarity:
  2036 
  2037   Context -- theory management operations (name, identity, inclusion,
  2038     parents, ancestors, merge, etc.), plus generic theory data;
  2039 
  2040   Sign -- logical signature and syntax operations (declaring consts,
  2041     types, etc.), plus certify/read for common entities;
  2042 
  2043   Theory -- logical theory operations (stating axioms, definitions,
  2044     oracles), plus a copy of logical signature operations (consts,
  2045     types, etc.); also a few basic management operations (Theory.copy,
  2046     Theory.merge, etc.)
  2047 
  2048 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2049 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2050 for convenience -- they merely return the theory.
  2051 
  2052 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2053 
  2054 * Pure: the Isar proof context type is already defined early in Pure
  2055 as Context.proof (note that ProofContext.context and Proof.context are
  2056 aliases, where the latter is the preferred name).  This enables other
  2057 Isabelle components to refer to that type even before Isar is present.
  2058 
  2059 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2060 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2061 any of these kinds.  For example, Sign.intern typeK is now
  2062 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2063 Theory.hide_types.  Also note that former
  2064 Theory.hide_classes/types/consts are now
  2065 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2066 internalize their arguments!  INCOMPATIBILITY.
  2067 
  2068 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2069 datatype thmref (with constructors Name and NameSelection) instead of
  2070 plain string -- INCOMPATIBILITY;
  2071 
  2072 * Pure: cases produced by proof methods specify options, where NONE
  2073 means to remove case bindings -- INCOMPATIBILITY in
  2074 (RAW_)METHOD_CASES.
  2075 
  2076 * Pure: the following operations retrieve axioms or theorems from a
  2077 theory node or theory hierarchy, respectively:
  2078 
  2079   Theory.axioms_of: theory -> (string * term) list
  2080   Theory.all_axioms_of: theory -> (string * term) list
  2081   PureThy.thms_of: theory -> (string * thm) list
  2082   PureThy.all_thms_of: theory -> (string * thm) list
  2083 
  2084 * Pure: print_tac now outputs the goal through the trace channel.
  2085 
  2086 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2087 Reference Toplevel.debug (default false) controls detailed printing
  2088 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2089 controls execution profiling -- set to 1 for time and 2 for space
  2090 (both increase the runtime).
  2091 
  2092 * Isar session: The initial use of ROOT.ML is now always timed,
  2093 i.e. the log will show the actual process times, in contrast to the
  2094 elapsed wall-clock time that the outer shell wrapper produces.
  2095 
  2096 * Simplifier: improved handling of bound variables (nameless
  2097 representation, avoid allocating new strings).  Simprocs that invoke
  2098 the Simplifier recursively should use Simplifier.inherit_bounds to
  2099 avoid local name clashes.  Failure to do so produces warnings
  2100 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2101 for further details.
  2102 
  2103 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2104 bindings for all theorems stored within a given theory; this may help
  2105 in porting non-Isar theories to Isar ones, while keeping ML proof
  2106 scripts for the time being.
  2107 
  2108 * ML operator HTML.with_charset specifies the charset begin used for
  2109 generated HTML files.  For example:
  2110 
  2111   HTML.with_charset "utf-8" use_thy "Hebrew";
  2112   HTML.with_charset "utf-8" use_thy "Chinese";
  2113 
  2114 
  2115 *** System ***
  2116 
  2117 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2118 isabelle, isatool etc.).
  2119 
  2120 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2121 isatool doc, isatool mkdir, display_drafts etc.).
  2122 
  2123 * isatool usedir: option -f allows specification of the ML file to be
  2124 used by Isabelle; default is ROOT.ML.
  2125 
  2126 * New isatool version outputs the version identifier of the Isabelle
  2127 distribution being used.
  2128 
  2129 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2130 (containing Boolean satisfiability problems) into Isabelle/HOL
  2131 theories.
  2132 
  2133 
  2134 
  2135 New in Isabelle2004 (April 2004)
  2136 --------------------------------
  2137 
  2138 *** General ***
  2139 
  2140 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2141   Replaces linorder.ML.
  2142 
  2143 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2144   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2145   (\<a>...\<z>), are now considered normal letters, and can therefore
  2146   be used anywhere where an ASCII letter (a...zA...Z) has until
  2147   now. COMPATIBILITY: This obviously changes the parsing of some
  2148   terms, especially where a symbol has been used as a binder, say
  2149   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2150   as an identifier.  Fix it by inserting a space around former
  2151   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2152   existing theory and ML files.
  2153 
  2154 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2155 
  2156 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2157   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2158   a normal (but invisible) letter. For multiple letter subscripts repeat
  2159   \<^isub> like this: x\<^isub>1\<^isub>2.
  2160 
  2161 * Pure: There are now sub-/superscripts that can span more than one
  2162   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2163   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2164   superscript. The new control characters are not identifier parts.
  2165 
  2166 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2167   content of "..." to the latex file instead of \isacntrl... . The "..."
  2168   may consist of any printable characters excluding the end bracket >.
  2169 
  2170 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2171   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2172   declare constants "final", which prevents their being given a definition
  2173   later.  It is useful for constants whose behaviour is fixed axiomatically
  2174   rather than definitionally, such as the meta-logic connectives.
  2175 
  2176 * Pure: 'instance' now handles general arities with general sorts
  2177   (i.e. intersections of classes),
  2178 
  2179 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2180   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2181   It can be changed to alter the colors/layout of generated pages.
  2182 
  2183 
  2184 *** Isar ***
  2185 
  2186 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2187   cut_tac, subgoal_tac and thin_tac:
  2188   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2189     locales are no longer forced to write Isar proof scripts.
  2190     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2191     emulations.
  2192   - INCOMPATIBILITY: names of variables to be instantiated may no
  2193     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2194     This is consistent with the instantiation attribute "where".
  2195 
  2196 * Attributes "where" and "of":
  2197   - Now take type variables of instantiated theorem into account when reading
  2198     the instantiation string.  This fixes a bug that caused instantiated
  2199     theorems to have too special types in some circumstances.
  2200   - "where" permits explicit instantiations of type variables.
  2201 
  2202 * Calculation commands "moreover" and "also" no longer interfere with
  2203   current facts ("this"), admitting arbitrary combinations with "then"
  2204   and derived forms.
  2205 
  2206 * Locales:
  2207   - Goal statements involving the context element "includes" no longer
  2208     generate theorems with internal delta predicates (those ending on
  2209     "_axioms") in the premise.
  2210     Resolve particular premise with <locale>.intro to obtain old form.
  2211   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2212     specification and "includes" elements in goal statement.
  2213   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2214     [intro?] and [elim?] (respectively) by default.
  2215   - Experimental command for instantiation of locales in proof contexts:
  2216         instantiate <label>[<attrs>]: <loc>
  2217     Instantiates locale <loc> and adds all its theorems to the current context
  2218     taking into account their attributes.  Label and attrs are optional
  2219     modifiers, like in theorem declarations.  If present, names of
  2220     instantiated theorems are qualified with <label>, and the attributes
  2221     <attrs> are applied after any attributes these theorems might have already.
  2222       If the locale has assumptions, a chained fact of the form
  2223     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2224     are derived.  The command does not support old-style locales declared
  2225     with "locale (open)".
  2226       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2227 
  2228 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2229   (Isar) contexts.
  2230 
  2231 
  2232 *** HOL ***
  2233 
  2234 * Proof import: new image HOL4 contains the imported library from
  2235   the HOL4 system with about 2500 theorems. It is imported by
  2236   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2237   can be used like any other Isabelle image.  See
  2238   HOL/Import/HOL/README for more information.
  2239 
  2240 * Simplifier:
  2241   - Much improved handling of linear and partial orders.
  2242     Reasoners for linear and partial orders are set up for type classes
  2243     "linorder" and "order" respectively, and are added to the default simpset
  2244     as solvers.  This means that the simplifier can build transitivity chains
  2245     to solve goals from the assumptions.
  2246   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2247     of blast or auto after simplification become unnecessary because the goal
  2248     is solved by simplification already.
  2249 
  2250 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2251     all proved in axiomatic type classes for semirings, rings and fields.
  2252 
  2253 * Numerics:
  2254   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2255     now formalized using the Ring_and_Field theory mentioned above.
  2256   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2257     than before, because now they are set up once in a generic manner.
  2258   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2259     Look for the general versions in Ring_and_Field (and Power if they concern
  2260     exponentiation).
  2261 
  2262 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2263 
  2264 * Records:
  2265   - Record types are now by default printed with their type abbreviation
  2266     instead of the list of all field types. This can be configured via
  2267     the reference "print_record_type_abbr".
  2268   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2269     (not enabled by default).
  2270   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2271     EX x. x = sel r to True (not enabled by default).
  2272   - Tactic "record_split_simp_tac" to split and simplify records added.
  2273 
  2274 * 'specification' command added, allowing for definition by
  2275   specification.  There is also an 'ax_specification' command that
  2276   introduces the new constants axiomatically.
  2277 
  2278 * arith(_tac) is now able to generate counterexamples for reals as well.
  2279 
  2280 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2281 
  2282 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2283   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2284 
  2285 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2286   matrix theory to linear programming.
  2287 
  2288 * Unions and Intersections:
  2289   The latex output syntax of UN and INT has been changed
  2290   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2291   i.e. the index formulae has become a subscript.
  2292   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2293 
  2294 * Unions and Intersections over Intervals:
  2295   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2296   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2297   like in normal math, and corresponding versions for < and for intersection.
  2298 
  2299 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2300   lexicographic dictonary ordering has been added as "lexord".
  2301 
  2302 * ML: the legacy theory structures Int and List have been removed. They had
  2303   conflicted with ML Basis Library structures having the same names.
  2304 
  2305 * 'refute' command added to search for (finite) countermodels.  Only works
  2306   for a fragment of HOL.  The installation of an external SAT solver is
  2307   highly recommended.  See "HOL/Refute.thy" for details.
  2308 
  2309 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2310   formulae under an assignment of free variables to random values.
  2311   In contrast to 'refute', it can deal with inductive datatypes,
  2312   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2313   for examples.
  2314 
  2315 
  2316 *** HOLCF ***
  2317 
  2318 * Streams now come with concatenation and are part of the HOLCF image
  2319 
  2320 
  2321 
  2322 New in Isabelle2003 (May 2003)
  2323 ------------------------------
  2324 
  2325 *** General ***
  2326 
  2327 * Provers/simplifier:
  2328 
  2329   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2330     Assumptions are now subject to complete mutual simplification,
  2331     not just from left to right. The simplifier now preserves
  2332     the order of assumptions.
  2333 
  2334     Potential INCOMPATIBILITY:
  2335 
  2336     -- simp sometimes diverges where the old version did
  2337        not, e.g. invoking simp on the goal
  2338 
  2339         [| P (f x); y = x; f x = f y |] ==> Q
  2340 
  2341        now gives rise to the infinite reduction sequence
  2342 
  2343         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2344 
  2345        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2346        kind of problem.
  2347 
  2348     -- Tactics combining classical reasoner and simplification (such as auto)
  2349        are also affected by this change, because many of them rely on
  2350        simp. They may sometimes diverge as well or yield a different numbers
  2351        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2352        in case of problems. Sometimes subsequent calls to the classical
  2353        reasoner will fail because a preceeding call to the simplifier too
  2354        eagerly simplified the goal, e.g. deleted redundant premises.
  2355 
  2356   - The simplifier trace now shows the names of the applied rewrite rules
  2357 
  2358   - You can limit the number of recursive invocations of the simplifier
  2359     during conditional rewriting (where the simplifie tries to solve the
  2360     conditions before applying the rewrite rule):
  2361     ML "simp_depth_limit := n"
  2362     where n is an integer. Thus you can force termination where previously
  2363     the simplifier would diverge.
  2364 
  2365   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2366 
  2367   - No longer aborts on failed congruence proof.  Instead, the
  2368     congruence is ignored.
  2369 
  2370 * Pure: New generic framework for extracting programs from constructive
  2371   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2372   as HOL/Extraction for some case studies.
  2373 
  2374 * Pure: The main goal of the proof state is no longer shown by default, only
  2375 the subgoals. This behaviour is controlled by a new flag.
  2376    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2377 (ML: Proof.show_main_goal).
  2378 
  2379 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2380 rules whose conclusion matches subgoal 1:
  2381       PG menu: Isabelle/Isar -> Show me -> matching rules
  2382 The rules are ordered by how closely they match the subgoal.
  2383 In particular, rules that solve a subgoal outright are displayed first
  2384 (or rather last, the way they are printed).
  2385 (ML: ProofGeneral.print_intros())
  2386 
  2387 * Pure: New flag trace_unify_fail causes unification to print
  2388 diagnostic information (PG: in trace buffer) when it fails. This is
  2389 useful for figuring out why single step proofs like rule, erule or
  2390 assumption failed.
  2391 
  2392 * Pure: Locale specifications now produce predicate definitions
  2393 according to the body of text (covering assumptions modulo local
  2394 definitions); predicate "loc_axioms" covers newly introduced text,
  2395 while "loc" is cumulative wrt. all included locale expressions; the
  2396 latter view is presented only on export into the global theory
  2397 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2398 on the old view without predicates;
  2399 
  2400 * Pure: predefined locales "var" and "struct" are useful for sharing
  2401 parameters (as in CASL, for example); just specify something like
  2402 ``var x + var y + struct M'' as import;
  2403 
  2404 * Pure: improved thms_containing: proper indexing of facts instead of
  2405 raw theorems; check validity of results wrt. current name space;
  2406 include local facts of proof configuration (also covers active
  2407 locales), cover fixed variables in index; may use "_" in term
  2408 specification; an optional limit for the number of printed facts may
  2409 be given (the default is 40);
  2410 
  2411 * Pure: disallow duplicate fact bindings within new-style theory files
  2412 (batch-mode only);
  2413 
  2414 * Provers: improved induct method: assumptions introduced by case
  2415 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2416 the goal statement); "foo" still refers to all facts collectively;
  2417 
  2418 * Provers: the function blast.overloaded has been removed: all constants
  2419 are regarded as potentially overloaded, which improves robustness in exchange
  2420 for slight decrease in efficiency;
  2421 
  2422 * Provers/linorder: New generic prover for transitivity reasoning over
  2423 linear orders.  Note: this prover is not efficient!
  2424 
  2425 * Isar: preview of problems to finish 'show' now produce an error
  2426 rather than just a warning (in interactive mode);
  2427 
  2428 
  2429 *** HOL ***
  2430 
  2431 * arith(_tac)
  2432 
  2433  - Produces a counter example if it cannot prove a goal.
  2434    Note that the counter example may be spurious if the goal is not a formula
  2435    of quantifier-free linear arithmetic.
  2436    In ProofGeneral the counter example appears in the trace buffer.
  2437 
  2438  - Knows about div k and mod k where k is a numeral of type nat or int.
  2439 
  2440  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2441    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2442    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2443 
  2444 * simp's arithmetic capabilities have been enhanced a bit: it now
  2445 takes ~= in premises into account (by performing a case split);
  2446 
  2447 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2448 are distributed over a sum of terms;
  2449 
  2450 * New tactic "trans_tac" and method "trans" instantiate
  2451 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2452 "<=", "<" and "=").
  2453 
  2454 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2455 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2456 
  2457 * 'typedef' command has new option "open" to suppress the set
  2458 definition;
  2459 
  2460 * functions Min and Max on finite sets have been introduced (theory
  2461 Finite_Set);
  2462 
  2463 * attribute [symmetric] now works for relations as well; it turns
  2464 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2465 
  2466 * induct over a !!-quantified statement (say !!x1..xn):
  2467   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2468 
  2469 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2470 %x. None. Warning: empty_def now refers to the previously hidden definition
  2471 of the empty set.
  2472 
  2473 * Algebra: formalization of classical algebra.  Intended as base for
  2474 any algebraic development in Isabelle.  Currently covers group theory
  2475 (up to Sylow's theorem) and ring theory (Universal Property of
  2476 Univariate Polynomials).  Contributions welcome;
  2477 
  2478 * GroupTheory: deleted, since its material has been moved to Algebra;
  2479 
  2480 * Complex: new directory of the complex numbers with numeric constants,
  2481 nonstandard complex numbers, and some complex analysis, standard and
  2482 nonstandard (Jacques Fleuriot);
  2483 
  2484 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2485 
  2486 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2487 Fleuriot);
  2488 
  2489 * Real/HahnBanach: updated and adapted to locales;
  2490 
  2491 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2492 Gray and Kramer);
  2493 
  2494 * UNITY: added the Meier-Sanders theory of progress sets;
  2495 
  2496 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2497 as abstract algorithms, instantiated to the JVM;
  2498 
  2499 * Bali: Java source language formalization. Type system, operational
  2500 semantics, axiomatic semantics. Supported language features:
  2501 classes, interfaces, objects,virtual methods, static methods,
  2502 static/instance fields, arrays, access modifiers, definite
  2503 assignment, exceptions.
  2504 
  2505 
  2506 *** ZF ***
  2507 
  2508 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2509 universe, etc.);
  2510 
  2511 * Main ZF: virtually all theories converted to new-style format;
  2512 
  2513 
  2514 *** ML ***
  2515 
  2516 * Pure: Tactic.prove provides sane interface for internal proofs;
  2517 omits the infamous "standard" operation, so this is more appropriate
  2518 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2519 
  2520 * Pure: improved error reporting of simprocs;
  2521 
  2522 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2523 up simprocs;
  2524 
  2525 
  2526 *** Document preparation ***
  2527 
  2528 * uses \par instead of \\ for line breaks in theory text. This may
  2529 shift some page breaks in large documents. To get the old behaviour
  2530 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2531 
  2532 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2533 other packages
  2534 
  2535 * \<euro> now needs package babel/greek instead of marvosym (which
  2536 broke \Rightarrow)
  2537 
  2538 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2539 textcomp package)
  2540 
  2541 
  2542 
  2543 New in Isabelle2002 (March 2002)
  2544 --------------------------------
  2545 
  2546 *** Document preparation ***
  2547 
  2548 * greatly simplified document preparation setup, including more
  2549 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2550 instructive isatool mkdir; users should basically be able to get
  2551 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2552 users may run a separate document processing stage manually like this:
  2553 "isatool usedir -D output HOL Test && isatool document Test/output";
  2554 
  2555 * theory dependency graph may now be incorporated into documents;
  2556 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2557 with \includegraphics of LaTeX;
  2558 
  2559 * proper spacing of consecutive markup elements, especially text
  2560 blocks after section headings;
  2561 
  2562 * support bold style (for single symbols only), input syntax is like
  2563 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2564 
  2565 * \<bullet> is now output as bold \cdot by default, which looks much
  2566 better in printed text;
  2567 
  2568 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2569 note that these symbols are currently unavailable in Proof General /
  2570 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2571 
  2572 * isatool latex no longer depends on changed TEXINPUTS, instead
  2573 isatool document copies the Isabelle style files to the target
  2574 location;
  2575 
  2576 
  2577 *** Isar ***
  2578 
  2579 * Pure/Provers: improved proof by cases and induction;
  2580   - 'case' command admits impromptu naming of parameters (such as
  2581     "case (Suc n)");
  2582   - 'induct' method divinates rule instantiation from the inductive
  2583     claim; no longer requires excessive ?P bindings for proper
  2584     instantiation of cases;
  2585   - 'induct' method properly enumerates all possibilities of set/type
  2586     rules; as a consequence facts may be also passed through *type*
  2587     rules without further ado;
  2588   - 'induct' method now derives symbolic cases from the *rulified*
  2589     rule (before it used to rulify cases stemming from the internal
  2590     atomized version); this means that the context of a non-atomic
  2591     statement becomes is included in the hypothesis, avoiding the
  2592     slightly cumbersome show "PROP ?case" form;
  2593   - 'induct' may now use elim-style induction rules without chaining
  2594     facts, using ``missing'' premises from the goal state; this allows
  2595     rules stemming from inductive sets to be applied in unstructured
  2596     scripts, while still benefitting from proper handling of non-atomic
  2597     statements; NB: major inductive premises need to be put first, all
  2598     the rest of the goal is passed through the induction;
  2599   - 'induct' proper support for mutual induction involving non-atomic
  2600     rule statements (uses the new concept of simultaneous goals, see
  2601     below);
  2602   - append all possible rule selections, but only use the first
  2603     success (no backtracking);
  2604   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2605   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2606   - added 'print_induct_rules' (covered by help item in recent Proof
  2607     General versions);
  2608   - moved induct/cases attributes to Pure, methods to Provers;
  2609   - generic method setup instantiated for FOL and HOL;
  2610 
  2611 * Pure: support multiple simultaneous goal statements, for example
  2612 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2613 meta-level mechanism, this acts as if several individual goals had
  2614 been stated separately; in particular common proof methods need to be
  2615 repeated in order to cover all claims; note that a single elimination
  2616 step is *not* sufficient to establish the two conjunctions, so this
  2617 fails:
  2618 
  2619   assume "A & B" then have A and B ..   (*".." fails*)
  2620 
  2621 better use "obtain" in situations as above; alternative refer to
  2622 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2623 
  2624 * Pure: proper integration with ``locales''; unlike the original
  2625 version by Florian Kammller, Isar locales package high-level proof
  2626 contexts rather than raw logical ones (e.g. we admit to include
  2627 attributes everywhere); operations on locales include merge and
  2628 rename; support for implicit arguments (``structures''); simultaneous
  2629 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2630 some examples;
  2631 
  2632 * Pure: the following commands have been ``localized'', supporting a
  2633 target locale specification "(in name)": 'lemma', 'theorem',
  2634 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2635 stored both within the locale and at the theory level (exported and
  2636 qualified by the locale name);
  2637 
  2638 * Pure: theory goals may now be specified in ``long'' form, with
  2639 ad-hoc contexts consisting of arbitrary locale elements. for example
  2640 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2641 definitions may be given, too); the result is a meta-level rule with
  2642 the context elements being discharged in the obvious way;
  2643 
  2644 * Pure: new proof command 'using' allows to augment currently used
  2645 facts after a goal statement ('using' is syntactically analogous to
  2646 'apply', but acts on the goal's facts only); this allows chained facts
  2647 to be separated into parts given before and after a claim, as in
  2648 ``from a and b have C using d and e <proof>'';
  2649 
  2650 * Pure: renamed "antecedent" case to "rule_context";
  2651 
  2652 * Pure: new 'judgment' command records explicit information about the
  2653 object-logic embedding (used by several tools internally); no longer
  2654 use hard-wired "Trueprop";
  2655 
  2656 * Pure: added 'corollary' command;
  2657 
  2658 * Pure: fixed 'token_translation' command;
  2659 
  2660 * Pure: removed obsolete 'exported' attribute;
  2661 
  2662 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2663 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2664 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2665 
  2666 * Pure: method 'atomize' presents local goal premises as object-level
  2667 statements (atomic meta-level propositions); setup controlled via
  2668 rewrite rules declarations of 'atomize' attribute; example
  2669 application: 'induct' method with proper rule statements in improper
  2670 proof *scripts*;
  2671 
  2672 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2673 now consider the syntactic context of assumptions, giving a better
  2674 chance to get type-inference of the arguments right (this is
  2675 especially important for locales);
  2676 
  2677 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2678 mode;
  2679 
  2680 * Pure/obtain: the formal conclusion "thesis", being marked as
  2681 ``internal'', may no longer be reference directly in the text;
  2682 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2683 situations;
  2684 
  2685 * Pure: generic 'sym' attribute which declares a rule both as pure
  2686 'elim?' and for the 'symmetric' operation;
  2687 
  2688 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2689 text; the fixed correlation with particular command syntax has been
  2690 discontinued;
  2691 
  2692 * Pure: new method 'rules' is particularly well-suited for proof
  2693 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2694 but often produces more compact proof terms with less detours;
  2695 
  2696 * Pure/Provers/classical: simplified integration with pure rule
  2697 attributes and methods; the classical "intro?/elim?/dest?"
  2698 declarations coincide with the pure ones; the "rule" method no longer
  2699 includes classically swapped intros; "intro" and "elim" methods no
  2700 longer pick rules from the context; also got rid of ML declarations
  2701 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2702 INCOMPATIBILITY;
  2703 
  2704 * Provers/classical: attribute 'swapped' produces classical inversions
  2705 of introduction rules;
  2706 
  2707 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2708 rules instead of full simplifier context; 'iff' attribute handles
  2709 conditional rules;
  2710 
  2711 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2712 
  2713 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2714 "(permissive)" option to recover old behavior;
  2715 
  2716 * HOL: 'inductive' no longer features separate (collective) attributes
  2717 for 'intros' (was found too confusing);
  2718 
  2719 * HOL: properly declared induction rules less_induct and
  2720 wf_induct_rule;
  2721 
  2722 
  2723 *** HOL ***
  2724 
  2725 * HOL: moved over to sane numeral syntax; the new policy is as
  2726 follows:
  2727 
  2728   - 0 and 1 are polymorphic constants, which are defined on any
  2729   numeric type (nat, int, real etc.);
  2730 
  2731   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2732   binary representation internally;
  2733 
  2734   - type nat has special constructor Suc, and generally prefers Suc 0
  2735   over 1::nat and Suc (Suc 0) over 2::nat;
  2736 
  2737 This change may cause significant problems of INCOMPATIBILITY; here
  2738 are some hints on converting existing sources:
  2739 
  2740   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2741   entities, so expressions involving "-" (unary or binary minus) need
  2742   to be spaced properly;
  2743 
  2744   - existing occurrences of "1" may need to be constraint "1::nat" or
  2745   even replaced by Suc 0; similar for old "2";
  2746 
  2747   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2748 
  2749   - remove all special provisions on numerals in proofs;
  2750 
  2751 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2752 representation (depends on bin_arith_simps in the default context);
  2753 
  2754 * HOL: symbolic syntax for x^2 (numeral 2);
  2755 
  2756 * HOL: the class of all HOL types is now called "type" rather than
  2757 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2758 in axclass/classes, instance/arities, and (usually rare) occurrences
  2759 in typings (of consts etc.); internally the class is called
  2760 "HOL.type", ML programs should refer to HOLogic.typeS;
  2761 
  2762 * HOL/record package improvements:
  2763   - new derived operations "fields" to build a partial record section,
  2764     "extend" to promote a fixed record to a record scheme, and
  2765     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2766     declared as simp by default;
  2767   - shared operations ("more", "fields", etc.) now need to be always
  2768     qualified) --- potential INCOMPATIBILITY;
  2769   - removed "make_scheme" operations (use "make" with "extend") --
  2770     INCOMPATIBILITY;
  2771   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2772   - provides cases/induct rules for use with corresponding Isar
  2773     methods (for concrete records, record schemes, concrete more
  2774     parts, and schematic more parts -- in that order);
  2775   - internal definitions directly based on a light-weight abstract
  2776     theory of product types over typedef rather than datatype;
  2777 
  2778 * HOL: generic code generator for generating executable ML code from
  2779 specifications; specific support for HOL constructs such as inductive
  2780 datatypes and sets, as well as recursive functions; can be invoked
  2781 via 'generate_code' theory section;
  2782 
  2783 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2784 
  2785 * HOL: consolidated and renamed several theories.  In particular:
  2786         Ord.thy has been absorbed into HOL.thy
  2787         String.thy has been absorbed into List.thy
  2788 
  2789 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2790 (beware of argument permutation!);
  2791 
  2792 * HOL: linorder_less_split superseded by linorder_cases;
  2793 
  2794 * HOL/List: "nodups" renamed to "distinct";
  2795 
  2796 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2797 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2798   - Ex_def has changed, now need to use some_eq_ex
  2799 
  2800 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2801 in this (rare) case use:
  2802 
  2803   delSWrapper "split_all_tac"
  2804   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2805 
  2806 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2807 MAY FAIL;
  2808 
  2809 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2810 Isabelle's type classes, ^ on functions and relations has too general
  2811 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2812 necessary to attach explicit type constraints;
  2813 
  2814 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2815 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2816 renamed accordingly (eg "compI" -> "rel_compI").
  2817 
  2818 * HOL: syntax translations now work properly with numerals and records
  2819 expressions;
  2820 
  2821 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2822 of "lam" -- INCOMPATIBILITY;
  2823 
  2824 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2825 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2826 renamed "Product_Type.unit";
  2827 
  2828 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2829 
  2830 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2831 the "cases" method);
  2832 
  2833 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2834 Florian Kammller);
  2835 
  2836 * HOL/IMP: updated and converted to new-style theory format; several
  2837 parts turned into readable document, with proper Isar proof texts and
  2838 some explanations (by Gerwin Klein);
  2839 
  2840 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2841 
  2842 * HOL-Hyperreal is now a logic image;
  2843 
  2844 
  2845 *** HOLCF ***
  2846 
  2847 * Isar: consts/constdefs supports mixfix syntax for continuous
  2848 operations;
  2849 
  2850 * Isar: domain package adapted to new-style theory format, e.g. see
  2851 HOLCF/ex/Dnat.thy;
  2852 
  2853 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2854 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2855 lift.induct_tac, always use UU instead of Undef;
  2856 
  2857 * HOLCF/IMP: updated and converted to new-style theory;
  2858 
  2859 
  2860 *** ZF ***
  2861 
  2862 * Isar: proper integration of logic-specific tools and packages,
  2863 including theory commands '(co)inductive', '(co)datatype',
  2864 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2865 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2866 
  2867 * theory Main no longer includes AC; for the Axiom of Choice, base
  2868 your theory on Main_ZFC;
  2869 
  2870 * the integer library now covers quotients and remainders, with many
  2871 laws relating division to addition, multiplication, etc.;
  2872 
  2873 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2874 typeless version of the formalism;
  2875 
  2876 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2877 format;
  2878 
  2879 * ZF/Induct: new directory for examples of inductive definitions,
  2880 including theory Multiset for multiset orderings; converted to
  2881 new-style theory format;
  2882 
  2883 * ZF: many new theorems about lists, ordinals, etc.;
  2884 
  2885 
  2886 *** General ***
  2887 
  2888 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2889 variable proof controls level of detail: 0 = no proofs (only oracle
  2890 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2891 also ref manual for further ML interfaces;
  2892 
  2893 * Pure/axclass: removed obsolete ML interface
  2894 goal_subclass/goal_arity;
  2895 
  2896 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2897 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2898 separate tokens, so expressions involving minus need to be spaced
  2899 properly;
  2900 
  2901 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2902 rather than "infixl" or "infixr";
  2903 
  2904 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2905 sort constraint specifications in type inference; e.g. "x::_::foo"
  2906 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2907 type variable);
  2908 
  2909 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2910 control output of nested => (types); the default behavior is
  2911 "type_brackets";
  2912 
  2913 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2914 tokens into AST constants;
  2915 
  2916 * Pure/syntax: prefer later declarations of translations and print
  2917 translation functions; potential INCOMPATIBILITY: need to reverse
  2918 multiple declarations for same syntax element constant;
  2919 
  2920 * Pure/show_hyps reset by default (in accordance to existing Isar
  2921 practice);
  2922 
  2923 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2924 addSafter;
  2925 
  2926 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2927 as well;
  2928 
  2929 * system: tested support for MacOS X; should be able to get Isabelle +
  2930 Proof General to work in a plain Terminal after installing Poly/ML
  2931 (e.g. from the Isabelle distribution area) and GNU bash alone
  2932 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2933 support requires further installations, e.g. from
  2934 http://fink.sourceforge.net/);
  2935 
  2936 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2937 
  2938 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2939 of 40 MB), cf. ML_OPTIONS;
  2940 
  2941 * system: Proof General keywords specification is now part of the
  2942 Isabelle distribution (see etc/isar-keywords.el);
  2943 
  2944 * system: support for persistent Proof General sessions (refrain from
  2945 outdating all loaded theories on startup); user may create writable
  2946 logic images like this: ``isabelle -q HOL Test'';
  2947 
  2948 * system: smart selection of Isabelle process versus Isabelle
  2949 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2950 run both "isabelle" and "Isabelle" even if file names are badly
  2951 damaged (executable inspects the case of the first letter of its own
  2952 name); added separate "isabelle-process" and "isabelle-interface";
  2953 
  2954 * system: refrain from any attempt at filtering input streams; no
  2955 longer support ``8bit'' encoding of old isabelle font, instead proper
  2956 iso-latin characters may now be used; the related isatools
  2957 "symbolinput" and "nonascii" have disappeared as well;
  2958 
  2959 * system: removed old "xterm" interface (the print modes "xterm" and
  2960 "xterm_color" are still available for direct use in a suitable
  2961 terminal);
  2962 
  2963 
  2964 
  2965 New in Isabelle99-2 (February 2001)
  2966 -----------------------------------
  2967 
  2968 *** Overview of INCOMPATIBILITIES ***
  2969 
  2970 * HOL: please note that theories in the Library and elsewhere often use the
  2971 new-style (Isar) format; to refer to their theorems in an ML script you must
  2972 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2973 
  2974 * HOL: inductive package no longer splits induction rule aggressively,
  2975 but only as far as specified by the introductions given; the old
  2976 format may be recovered via ML function complete_split_rule or attribute
  2977 'split_rule (complete)';
  2978 
  2979 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2980 gfp_Tarski to gfp_unfold;
  2981 
  2982 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2983 
  2984 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2985 relation); infix "^^" has been renamed "``"; infix "``" has been
  2986 renamed "`"; "univalent" has been renamed "single_valued";
  2987 
  2988 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2989 operation;
  2990 
  2991 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2992 
  2993 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2994 
  2995 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2996 consequence, it is no longer monotonic wrt. the local goal context
  2997 (which is now passed through the inductive cases);
  2998 
  2999 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3000 \<gg> to \<ggreater>;
  3001 
  3002 
  3003 *** Document preparation ***
  3004 
  3005 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3006 available: are "it" for near math-mode best-style output, "sl" for
  3007 slanted text style, and "tt" for plain type-writer; if no
  3008 \isabellestyle command is given, output is according to slanted
  3009 type-writer);
  3010 
  3011 * support sub/super scripts (for single symbols only), input syntax is
  3012 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3013 
  3014 * some more standard symbols; see Appendix A of the system manual for
  3015 the complete list of symbols defined in isabellesym.sty;
  3016 
  3017 * improved isabelle style files; more abstract symbol implementation
  3018 (should now use \isamath{...} and \isatext{...} in custom symbol
  3019 definitions);
  3020 
  3021 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3022 state; Note that presentation of goal states does not conform to
  3023 actual human-readable proof documents.  Please do not include goal
  3024 states into document output unless you really know what you are doing!
  3025 
  3026 * proper indentation of antiquoted output with proportional LaTeX
  3027 fonts;
  3028 
  3029 * no_document ML operator temporarily disables LaTeX document
  3030 generation;
  3031 
  3032 * isatool unsymbolize tunes sources for plain ASCII communication;
  3033 
  3034 
  3035 *** Isar ***
  3036 
  3037 * Pure: Isar now suffers initial goal statements to contain unbound
  3038 schematic variables (this does not conform to actual readable proof
  3039 documents, due to unpredictable outcome and non-compositional proof
  3040 checking); users who know what they are doing may use schematic goals
  3041 for Prolog-style synthesis of proven results;
  3042 
  3043 * Pure: assumption method (an implicit finishing) now handles actual
  3044 rules as well;
  3045 
  3046 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3047 initial goal, declare "that" only as Pure intro (only for single
  3048 steps); the "that" rule assumption may now be involved in implicit
  3049 finishing, thus ".." becomes a feasible for trivial obtains;
  3050 
  3051 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3052 instance proofs may be performed by "..";
  3053 
  3054 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3055 statements as well;
  3056 
  3057 * Pure: more robust selection of calculational rules;
  3058 
  3059 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3060 rule (as well as the assumption rule);
  3061 
  3062 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3063 lemmas, using the graph browser tool;
  3064 
  3065 * Pure: predict failure of "show" in interactive mode;
  3066 
  3067 * Pure: 'thms_containing' now takes actual terms as arguments;
  3068 
  3069 * HOL: improved method 'induct' --- now handles non-atomic goals
  3070 (potential INCOMPATIBILITY); tuned error handling;
  3071 
  3072 * HOL: cases and induct rules now provide explicit hints about the
  3073 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3074 any remaining facts are inserted into the goal verbatim;
  3075 
  3076 * HOL: local contexts (aka cases) may now contain term bindings as
  3077 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3078 the result to be shown in each case;
  3079 
  3080 * HOL: added 'recdef_tc' command;
  3081 
  3082 * isatool convert assists in eliminating legacy ML scripts;
  3083 
  3084 
  3085 *** HOL ***
  3086 
  3087 * HOL/Library: a collection of generic theories to be used together
  3088 with main HOL; the theory loader path already includes this directory
  3089 by default; the following existing theories have been moved here:
  3090 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3091 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3092 
  3093 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3094 modelling and verification task performed in Isabelle/HOL +
  3095 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3096 
  3097 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3098 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3099 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3100 'domain', this makes the theory consistent with mathematical
  3101 literature;
  3102 
  3103 * HOL basics: added overloaded operations "inverse" and "divide"
  3104 (infix "/"), syntax for generic "abs" operation, generic summation
  3105 operator \<Sum>;
  3106 
  3107 * HOL/typedef: simplified package, provide more useful rules (see also
  3108 HOL/subset.thy);
  3109 
  3110 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3111 now expressed as a proper nested rule (old-style tactic scripts may
  3112 require atomize_strip_tac to cope with non-atomic premises);
  3113 
  3114 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3115 to "split_conv" (old name still available for compatibility);
  3116 
  3117 * HOL: improved concrete syntax for strings (e.g. allows translation
  3118 rules with string literals);
  3119 
  3120 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3121  and Fleuriot's mechanization of analysis, including the transcendental
  3122  functions for the reals;
  3123 
  3124 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3125 
  3126 
  3127 *** CTT ***
  3128 
  3129 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3130 "lam" is displayed as TWO lambda-symbols
  3131 
  3132 * CTT: theory Main now available, containing everything (that is, Bool
  3133 and Arith);
  3134 
  3135 
  3136 *** General ***
  3137 
  3138 * Pure: the Simplifier has been implemented properly as a derived rule
  3139 outside of the actual kernel (at last!); the overall performance
  3140 penalty in practical applications is about 50%, while reliability of
  3141 the Isabelle inference kernel has been greatly improved;
  3142 
  3143 * print modes "brackets" and "no_brackets" control output of nested =>
  3144 (types) and ==> (props); the default behaviour is "brackets";
  3145 
  3146 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3147 as assumptions as well;
  3148 
  3149 * system: support Poly/ML 4.0;
  3150 
  3151 * system: isatool install handles KDE version 1 or 2;
  3152 
  3153 
  3154 
  3155 New in Isabelle99-1 (October 2000)
  3156 ----------------------------------
  3157 
  3158 *** Overview of INCOMPATIBILITIES ***
  3159 
  3160 * HOL: simplification of natural numbers is much changed; to partly
  3161 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3162 issue the following ML commands:
  3163 
  3164   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3165   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3166 
  3167 * HOL: simplification no longer dives into case-expressions; this is
  3168 controlled by "t.weak_case_cong" for each datatype t;
  3169 
  3170 * HOL: nat_less_induct renamed to less_induct;
  3171 
  3172 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3173 fixsome to patch .thy and .ML sources automatically;
  3174 
  3175   select_equality  -> some_equality
  3176   select_eq_Ex     -> some_eq_ex
  3177   selectI2EX       -> someI2_ex
  3178   selectI2         -> someI2
  3179   selectI          -> someI
  3180   select1_equality -> some1_equality
  3181   Eps_sym_eq       -> some_sym_eq_trivial
  3182   Eps_eq           -> some_eq_trivial
  3183 
  3184 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3185 
  3186 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3187 instead);
  3188 
  3189 * HOL: the recursion equations generated by 'recdef' are now called
  3190 f.simps instead of f.rules;
  3191 
  3192 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3193 
  3194 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3195 sometimes be needed;
  3196 
  3197 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3198 
  3199 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3200 
  3201 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3202 product is now "<*>" instead of "Times"; the lexicographic product is
  3203 now "<*lex*>" instead of "**";
  3204 
  3205 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3206 of main HOL, but was unused); better use HOL's datatype package;
  3207 
  3208 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3209 the old syntax may be recovered as follows:
  3210 
  3211   syntax (symbols)
  3212     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3213       (infixl "\\<oplus>" 100)
  3214 
  3215 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3216 
  3217 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3218 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3219 internally;
  3220 
  3221 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3222 changed from A/r to A//r;
  3223 
  3224 * ZF: new treatment of arithmetic (nat & int) may break some old
  3225 proofs;
  3226 
  3227 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3228 rulify -> rule_format, elimify -> elim_format, ...);
  3229 
  3230 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3231 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3232 should have to change intro!! to intro? only); replaced "delrule" by
  3233 "rule del";
  3234 
  3235 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3236 
  3237 * Provers: strengthened force_tac by using new first_best_tac;
  3238 
  3239 * LaTeX document preparation: several changes of isabelle.sty (see
  3240 lib/texinputs);
  3241 
  3242 
  3243 *** Document preparation ***
  3244 
  3245 * formal comments (text blocks etc.) in new-style theories may now
  3246 contain antiquotations of thm/prop/term/typ/text to be presented
  3247 according to latex print mode; concrete syntax is like this:
  3248 @{term[show_types] "f(x) = a + x"};
  3249 
  3250 * isatool mkdir provides easy setup of Isabelle session directories,
  3251 including proper document sources;
  3252 
  3253 * generated LaTeX sources are now deleted after successful run
  3254 (isatool document -c); may retain a copy somewhere else via -D option
  3255 of isatool usedir;
  3256 
  3257 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3258 style files, achieving self-contained LaTeX sources and simplifying
  3259 LaTeX debugging;
  3260 
  3261 * old-style theories now produce (crude) LaTeX output as well;
  3262 
  3263 * browser info session directories are now self-contained (may be put
  3264 on WWW server seperately); improved graphs of nested sessions; removed
  3265 graph for 'all sessions';
  3266 
  3267 * several improvements in isabelle style files; \isabellestyle{it}
  3268 produces fake math mode output; \isamarkupheader is now \section by
  3269 default; see lib/texinputs/isabelle.sty etc.;
  3270 
  3271 
  3272 *** Isar ***
  3273 
  3274 * Isar/Pure: local results and corresponding term bindings are now
  3275 subject to Hindley-Milner polymorphism (similar to ML); this
  3276 accommodates incremental type-inference very nicely;
  3277 
  3278 * Isar/Pure: new derived language element 'obtain' supports
  3279 generalized existence reasoning;
  3280 
  3281 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3282 support accumulation of results, without applying any rules yet;
  3283 useful to collect intermediate results without explicit name
  3284 references, and for use with transitivity rules with more than 2
  3285 premises;
  3286 
  3287 * Isar/Pure: scalable support for case-analysis type proofs: new
  3288 'case' language element refers to local contexts symbolically, as
  3289 produced by certain proof methods; internally, case names are attached
  3290 to theorems as "tags";
  3291 
  3292 * Isar/Pure: theory command 'hide' removes declarations from
  3293 class/type/const name spaces;
  3294 
  3295 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3296 indicate potential overloading;
  3297 
  3298 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3299 
  3300 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3301 "{a,b,c}" instead of {a,b,c};
  3302 
  3303 * Isar/Pure now provides its own version of intro/elim/dest
  3304 attributes; useful for building new logics, but beware of confusion
  3305 with the version in Provers/classical;
  3306 
  3307 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3308 case name 'antecedent';
  3309 
  3310 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3311 to the current context is now done automatically);
  3312 
  3313 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3314 for definining proof methods in ML;
  3315 
  3316 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3317 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3318 most cases, one should have to change intro!! to intro? only);
  3319 replaced "delrule" by "rule del";
  3320 
  3321 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3322 'symmetric' attribute (the latter supercedes [RS sym]);
  3323 
  3324 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3325 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3326 well (including splits);
  3327 
  3328 * Isar/Provers: Simplifier and Classical methods now support all kind
  3329 of modifiers used in the past, including 'cong', 'iff', etc.
  3330 
  3331 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3332 of Simplifier and Classical reasoner);
  3333 
  3334 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3335 now support named cases; major packages (inductive, datatype, primrec,
  3336 recdef) support case names and properly name parameters;
  3337 
  3338 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3339 monotonicity conditions are extracted to be proven at end of
  3340 calculations;
  3341 
  3342 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3343 method anyway;
  3344 
  3345 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3346 split_if split_if_asm; datatype package provides theorems foo.splits =
  3347 foo.split foo.split_asm for each datatype;
  3348 
  3349 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3350 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3351 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3352 use "(cases (simplified))" method in proper proof texts);
  3353 
  3354 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3355 
  3356 * Isar: names of theorems etc. may be natural numbers as well;
  3357 
  3358 * Isar: 'pr' command: optional arguments for goals_limit and
  3359 ProofContext.prems_limit; no longer prints theory contexts, but only
  3360 proof states;
  3361 
  3362 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3363 additional print modes to be specified; e.g. "pr(latex)" will print
  3364 proof state according to the Isabelle LaTeX style;
  3365 
  3366 * Isar: improved support for emulating tactic scripts, including proof
  3367 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3368 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3369 (for HOL datatypes);
  3370 
  3371 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3372 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3373 'proof method scripts' have to be in depth-first order;
  3374 
  3375 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3376 
  3377 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3378 should instead use individual commands for printing items
  3379 (print_commands, print_methods etc.);
  3380 
  3381 * Isar: added 'nothing' --- the empty list of theorems;
  3382 
  3383 
  3384 *** HOL ***
  3385 
  3386 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3387 corresponding virtual machine and a specification of its bytecode
  3388 verifier and a lightweight bytecode verifier, including proofs of
  3389 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3390 Cornelia Pusch (see also the homepage of project Bali at
  3391 http://isabelle.in.tum.de/Bali/);
  3392 
  3393 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3394 Clemens Ballarin;
  3395 
  3396 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3397 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3398 Rasmussen;
  3399 
  3400 * HOL/Lattice: fundamental concepts of lattice theory and order
  3401 structures, including duals, properties of bounds versus algebraic
  3402 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3403 Theorem for complete lattices etc.; may also serve as a demonstration
  3404 for abstract algebraic reasoning using axiomatic type classes, and
  3405 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3406 
  3407 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3408 von Oheimb;
  3409 
  3410 * HOL/IMPP: extension of IMP with local variables and mutually
  3411 recursive procedures, by David von Oheimb;
  3412 
  3413 * HOL/Lambda: converted into new-style theory and document;
  3414 
  3415 * HOL/ex/Multiquote: example of multiple nested quotations and
  3416 anti-quotations -- basically a generalized version of de-Bruijn
  3417 representation; very useful in avoiding lifting of operations;
  3418 
  3419 * HOL/record: added general record equality rule to simpset; fixed
  3420 select-update simplification procedure to handle extended records as
  3421 well; admit "r" as field name;
  3422 
  3423 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3424 other numeric types and also as the identity of groups, rings, etc.;
  3425 
  3426 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3427 Types nat and int belong to this axclass;
  3428 
  3429 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3430    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3431    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3432   two terms #m*u and #n*u are replaced by #(m+n)*u
  3433     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3434   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3435     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3436 
  3437 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3438 powerful prover for predicate logic but knows nothing of clasets; see
  3439 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3440 
  3441 * HOL: new version of "case_tac" subsumes both boolean case split and
  3442 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3443 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3444 
  3445 * HOL: simplification no longer dives into case-expressions: only the
  3446 selector expression is simplified, but not the remaining arms; to
  3447 enable full simplification of case-expressions for datatype t, you may
  3448 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3449 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3450 
  3451 * HOL/recdef: the recursion equations generated by 'recdef' for
  3452 function 'f' are now called f.simps instead of f.rules; if all
  3453 termination conditions are proved automatically, these simplification
  3454 rules are added to the simpset, as in primrec; rules may be named
  3455 individually as well, resulting in a separate list of theorems for
  3456 each equation;
  3457 
  3458 * HOL/While is a new theory that provides a while-combinator. It
  3459 permits the definition of tail-recursive functions without the
  3460 provision of a termination measure. The latter is necessary once the
  3461 invariant proof rule for while is applied.
  3462 
  3463 * HOL: new (overloaded) notation for the set of elements below/above
  3464 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3465 
  3466 * HOL: theorems impI, allI, ballI bound as "strip";
  3467 
  3468 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3469 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3470 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3471 
  3472 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3473 
  3474 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3475 main HOL, but was unused);
  3476 
  3477 * HOL: fewer consts declared as global (e.g. have to refer to
  3478 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3479 
  3480 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3481 in case of overlap with user translations (e.g. judgements over
  3482 tuples); (note that the underlying logical represenation is still
  3483 bogus);
  3484 
  3485 
  3486 *** ZF ***
  3487 
  3488 * ZF: simplification automatically cancels common terms in arithmetic
  3489 expressions over nat and int;
  3490 
  3491 * ZF: new treatment of nat to minimize type-checking: all operators
  3492 coerce their operands to a natural number using the function natify,
  3493 making the algebraic laws unconditional;
  3494 
  3495 * ZF: as above, for int: operators coerce their operands to an integer
  3496 using the function intify;
  3497 
  3498 * ZF: the integer library now contains many of the usual laws for the
  3499 orderings, including $<=, and monotonicity laws for $+ and $*;
  3500 
  3501 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3502 simplification;
  3503 
  3504 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3505 to the simplifier and classical reasoner simultaneously;
  3506 
  3507 
  3508 *** General ***
  3509 
  3510 * Provers: blast_tac now handles actual object-logic rules as
  3511 assumptions; note that auto_tac uses blast_tac internally as well;
  3512 
  3513 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3514 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3515 
  3516 * Provers: delrules now handles destruct rules as well (no longer need
  3517 explicit make_elim);
  3518 
  3519 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3520   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3521 use instead the strong form,
  3522   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3523 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3524 from destruct-rules;
  3525 
  3526 * Provers: Simplifier.easy_setup provides a fast path to basic
  3527 Simplifier setup for new object-logics;
  3528 
  3529 * Pure: AST translation rules no longer require constant head on LHS;
  3530 
  3531 * Pure: improved name spaces: ambiguous output is qualified; support
  3532 for hiding of names;
  3533 
  3534 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3535 XSYMBOL_HOME; no longer need to do manual configuration in most
  3536 situations;
  3537 
  3538 * system: compression of ML heaps images may now be controlled via -c
  3539 option of isabelle and isatool usedir (currently only observed by
  3540 Poly/ML);
  3541 
  3542 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3543 useful for remote X11);
  3544 
  3545 * system: provide TAGS file for Isabelle sources;
  3546 
  3547 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3548 order;
  3549 
  3550 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3551 timing flag supersedes proof_timing and Toplevel.trace;
  3552 
  3553 * ML: new combinators |>> and |>>> for incremental transformations
  3554 with secondary results (e.g. certain theory extensions):
  3555 
  3556 * ML: PureThy.add_defs gets additional argument to indicate potential
  3557 overloading (usually false);
  3558 
  3559 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3560 results;
  3561 
  3562 
  3563 
  3564 New in Isabelle99 (October 1999)
  3565 --------------------------------
  3566 
  3567 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3568 
  3569 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3570 are no longer simplified.  (This allows the simplifier to unfold recursive
  3571 functional programs.)  To restore the old behaviour, declare
  3572 
  3573     Delcongs [if_weak_cong];
  3574 
  3575 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3576 complement;
  3577 
  3578 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3579 
  3580 * HOL/datatype: mutual_induct_tac no longer exists --
  3581   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3582 
  3583 * HOL/typedef: fixed type inference for representing set; type
  3584 arguments now have to occur explicitly on the rhs as type constraints;
  3585 
  3586 * ZF: The con_defs part of an inductive definition may no longer refer
  3587 to constants declared in the same theory;
  3588 
  3589 * HOL, ZF: the function mk_cases, generated by the inductive
  3590 definition package, has lost an argument.  To simplify its result, it
  3591 uses the default simpset instead of a supplied list of theorems.
  3592 
  3593 * HOL/List: the constructors of type list are now Nil and Cons;
  3594 
  3595 * Simplifier: the type of the infix ML functions
  3596         setSSolver addSSolver setSolver addSolver
  3597 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3598 for packaging solvers. A solver is created via
  3599         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3600 where the string argument is only a comment.
  3601 
  3602 
  3603 *** Proof tools ***
  3604 
  3605 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3606 decision procedure for linear arithmetic. Currently it is used for
  3607 types `nat', `int', and `real' in HOL (see below); it can, should and
  3608 will be instantiated for other types and logics as well.
  3609 
  3610 * The simplifier now accepts rewrite rules with flexible heads, eg
  3611      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3612   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3613   matching.
  3614 
  3615 
  3616 *** General ***
  3617 
  3618 * New Isabelle/Isar subsystem provides an alternative to traditional
  3619 tactical theorem proving; together with the ProofGeneral/isar user
  3620 interface it offers an interactive environment for developing human
  3621 readable proof documents (Isar == Intelligible semi-automated
  3622 reasoning); for further information see isatool doc isar-ref,
  3623 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3624 
  3625 * improved and simplified presentation of theories: better HTML markup
  3626 (including colors), graph views in several sizes; isatool usedir now
  3627 provides a proper interface for user theories (via -P option); actual
  3628 document preparation based on (PDF)LaTeX is available as well (for
  3629 new-style theories only); see isatool doc system for more information;
  3630 
  3631 * native support for Proof General, both for classic Isabelle and
  3632 Isabelle/Isar;
  3633 
  3634 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3635 using the graph browser tool;
  3636 
  3637 * Isabelle manuals now also available as PDF;
  3638 
  3639 * theory loader rewritten from scratch (may not be fully
  3640 bug-compatible); old loadpath variable has been replaced by show_path,
  3641 add_path, del_path, reset_path functions; new operations such as
  3642 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3643 isatool doc ref);
  3644 
  3645 * improved isatool install: option -k creates KDE application icon,
  3646 option -p DIR installs standalone binaries;
  3647 
  3648 * added ML_PLATFORM setting (useful for cross-platform installations);
  3649 more robust handling of platform specific ML images for SML/NJ;
  3650 
  3651 * the settings environment is now statically scoped, i.e. it is never
  3652 created again in sub-processes invoked from isabelle, isatool, or
  3653 Isabelle;
  3654 
  3655 * path element specification '~~' refers to '$ISABELLE_HOME';
  3656 
  3657 * in locales, the "assumes" and "defines" parts may be omitted if
  3658 empty;
  3659 
  3660 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3661 long arrows);
  3662 
  3663 * new print_mode "HTML";
  3664 
  3665 * new flag show_tags controls display of tags of theorems (which are
  3666 basically just comments that may be attached by some tools);
  3667 
  3668 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3669 mode and goal output format:
  3670 
  3671 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3672 244c244
  3673 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3674 ---
  3675 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3676 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3677 181c181
  3678 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3679 ---
  3680 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3681 
  3682 * function bind_thms stores lists of theorems (cf. bind_thm);
  3683 
  3684 * new shorthand tactics ftac, eatac, datac, fatac;
  3685 
  3686 * qed (and friends) now accept "" as result name; in that case the
  3687 theorem is not stored, but proper checks and presentation of the
  3688 result still apply;
  3689 
  3690 * theorem database now also indexes constants "Trueprop", "all",
  3691 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3692 
  3693 
  3694 *** HOL ***
  3695 
  3696 ** HOL arithmetic **
  3697 
  3698 * There are now decision procedures for linear arithmetic over nat and
  3699 int:
  3700 
  3701 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3702 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3703 are treated as atomic; subformulae not involving type `nat' or `int'
  3704 are ignored; quantified subformulae are ignored unless they are
  3705 positive universal or negative existential. The tactic has to be
  3706 invoked by hand and can be a little bit slow. In particular, the
  3707 running time is exponential in the number of occurrences of `min' and
  3708 `max', and `-' on `nat'.
  3709 
  3710 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3711 (negated) (in)equalities among the premises and the conclusion into
  3712 account (i.e. no compound formulae) and does not know about `min' and
  3713 `max', and `-' on `nat'. It is fast and is used automatically by the
  3714 simplifier.
  3715 
  3716 NB: At the moment, these decision procedures do not cope with mixed
  3717 nat/int formulae where the two parts interact, such as `m < n ==>
  3718 int(m) < int(n)'.
  3719 
  3720 * HOL/Numeral provides a generic theory of numerals (encoded
  3721 efficiently as bit strings); setup for types nat/int/real is in place;
  3722 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3723 int, existing theories and proof scripts may require a few additional
  3724 type constraints;
  3725 
  3726 * integer division and remainder can now be performed on constant
  3727 arguments;
  3728 
  3729 * many properties of integer multiplication, division and remainder
  3730 are now available;
  3731 
  3732 * An interface to the Stanford Validity Checker (SVC) is available through the
  3733 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3734 are proved automatically.  SVC must be installed separately, and its results
  3735 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3736 invocation of the underlying oracle).  For SVC see
  3737   http://verify.stanford.edu/SVC
  3738 
  3739 * IsaMakefile: the HOL-Real target now builds an actual image;
  3740 
  3741 
  3742 ** HOL misc **
  3743 
  3744 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3745 (in Isabelle/Isar) -- by Gertrud Bauer;
  3746 
  3747 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3748 analysis for assembly languages with subtypes;
  3749 
  3750 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3751 -- avoids syntactic ambiguities and treats state, transition, and
  3752 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3753 changed syntax and (many) tactics;
  3754 
  3755 * HOL/inductive: Now also handles more general introduction rules such
  3756   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3757   theorems are now maintained within the theory (maintained via the
  3758   "mono" attribute);
  3759 
  3760 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3761   (using function types) such as
  3762 
  3763   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3764 
  3765 * HOL/record: record_simproc (part of the default simpset) takes care
  3766 of selectors applied to updated records; record_split_tac is no longer
  3767 part of the default claset; update_defs may now be removed from the
  3768 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3769 
  3770   claset_ref () := claset() addSWrapper record_split_wrapper;
  3771   Delsimprocs [record_simproc]
  3772 
  3773 * HOL/typedef: fixed type inference for representing set; type
  3774 arguments now have to occur explicitly on the rhs as type constraints;
  3775 
  3776 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3777 names rather than an ML expression;
  3778 
  3779 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3780 supplied later.  Program schemes can be defined, such as
  3781     "While B C s = (if B s then While B C (C s) else s)"
  3782 where the well-founded relation can be chosen after B and C have been given.
  3783 
  3784 * HOL/List: the constructors of type list are now Nil and Cons;
  3785 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3786 course, ML tools referring to List.list.op # etc. have to be adapted;
  3787 
  3788 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3789 disabled by default; run isabelle with option -m HOL to get back to
  3790 the original Gordon/HOL-style output;
  3791 
  3792 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3793 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3794 
  3795 * HOL basic syntax simplified (more orthogonal): all variants of
  3796 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3797 Eps operator is provided as well: "SOME x. P[x]";
  3798 
  3799 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3800 
  3801 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3802 thus available for user theories;
  3803 
  3804 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3805 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3806 time;
  3807 
  3808 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3809 several times and then mp;
  3810 
  3811 
  3812 *** LK ***
  3813 
  3814 * the notation <<...>> is now available as a notation for sequences of
  3815 formulas;
  3816 
  3817 * the simplifier is now installed
  3818 
  3819 * the axiom system has been generalized (thanks to Soren Heilmann)
  3820 
  3821 * the classical reasoner now has a default rule database
  3822 
  3823 
  3824 *** ZF ***
  3825 
  3826 * new primrec section allows primitive recursive functions to be given
  3827 directly (as in HOL) over datatypes and the natural numbers;
  3828 
  3829 * new tactics induct_tac and exhaust_tac for induction (or case
  3830 analysis) over datatypes and the natural numbers;
  3831 
  3832 * the datatype declaration of type T now defines the recursor T_rec;
  3833 
  3834 * simplification automatically does freeness reasoning for datatype
  3835 constructors;
  3836 
  3837 * automatic type-inference, with AddTCs command to insert new
  3838 type-checking rules;
  3839 
  3840 * datatype introduction rules are now added as Safe Introduction rules
  3841 to the claset;
  3842 
  3843 * the syntax "if P then x else y" is now available in addition to
  3844 if(P,x,y);
  3845 
  3846 
  3847 *** Internal programming interfaces ***
  3848 
  3849 * tuned simplifier trace output; new flag debug_simp;
  3850 
  3851 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3852 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3853 
  3854 * AxClass.axclass_tac lost the theory argument;
  3855 
  3856 * tuned current_goals_markers semantics: begin / end goal avoids
  3857 printing empty lines;
  3858 
  3859 * removed prs and prs_fn hook, which was broken because it did not
  3860 include \n in its semantics, forcing writeln to add one
  3861 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3862 string -> unit if you really want to output text without newline;
  3863 
  3864 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3865 plain output, interface builders may have to enable 'isabelle_font'
  3866 mode to get Isabelle font glyphs as before;
  3867 
  3868 * refined token_translation interface; INCOMPATIBILITY: output length
  3869 now of type real instead of int;
  3870 
  3871 * theory loader actions may be traced via new ThyInfo.add_hook
  3872 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3873 your own database of information attached to *whole* theories -- as
  3874 opposed to intra-theory data slots offered via TheoryDataFun;
  3875 
  3876 * proper handling of dangling sort hypotheses (at last!);
  3877 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3878 extra sort hypotheses that can be witnessed from the type signature;
  3879 the force_strip_shyps flag is gone, any remaining shyps are simply
  3880 left in the theorem (with a warning issued by strip_shyps_warning);
  3881 
  3882 
  3883 
  3884 New in Isabelle98-1 (October 1998)
  3885 ----------------------------------
  3886 
  3887 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3888 
  3889 * several changes of automated proof tools;
  3890 
  3891 * HOL: major changes to the inductive and datatype packages, including
  3892 some minor incompatibilities of theory syntax;
  3893 
  3894 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3895 called `inj_on';
  3896 
  3897 * HOL: removed duplicate thms in Arith:
  3898   less_imp_add_less  should be replaced by  trans_less_add1
  3899   le_imp_add_le      should be replaced by  trans_le_add1
  3900 
  3901 * HOL: unary minus is now overloaded (new type constraints may be
  3902 required);
  3903 
  3904 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3905 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3906 now taken as an integer constant.
  3907 
  3908 * Pure: ML function 'theory_of' renamed to 'theory';
  3909 
  3910 
  3911 *** Proof tools ***
  3912 
  3913 * Simplifier:
  3914   1. Asm_full_simp_tac is now more aggressive.
  3915      1. It will sometimes reorient premises if that increases their power to
  3916         simplify.
  3917      2. It does no longer proceed strictly from left to right but may also
  3918         rotate premises to achieve further simplification.
  3919      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3920      old Asm_full_simp_tac in that it does not rotate premises.
  3921   2. The simplifier now knows a little bit about nat-arithmetic.
  3922 
  3923 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3924 allows for selected deletion of wrappers, by introduction of names for
  3925 wrapper functionals.  This implies that addbefore, addSbefore,
  3926 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3927 and that adding two tactics with the same name overwrites the first
  3928 one (emitting a warning).
  3929   type wrapper = (int -> tactic) -> (int -> tactic)
  3930   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3931   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3932   delWrapper, delSWrapper: claset *  string            -> claset
  3933   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3934 
  3935 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3936 semantics; addbefore now affects only the unsafe part of step_tac
  3937 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3938 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3939 by Force_tac;
  3940 
  3941 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3942 compWrapper; added safe wrapper (and access functions for it);
  3943 
  3944 * HOL/split_all_tac is now much faster and fails if there is nothing
  3945 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3946 and the names of the automatically generated variables have changed.
  3947 split_all_tac has moved within claset() from unsafe wrappers to safe
  3948 wrappers, which means that !!-bound variables are split much more
  3949 aggressively, and safe_tac and clarify_tac now split such variables.
  3950 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3951 Note: the same holds for record_split_tac, which does the job of
  3952 split_all_tac for record fields.
  3953 
  3954 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3955 permanently to the default simpset using Addsplits just like
  3956 Addsimps. They can be removed via Delsplits just like
  3957 Delsimps. Lower-case versions are also available.
  3958 
  3959 * HOL/Simplifier: The rule split_if is now part of the default
  3960 simpset. This means that the simplifier will eliminate all occurrences
  3961 of if-then-else in the conclusion of a goal. To prevent this, you can
  3962 either remove split_if completely from the default simpset by
  3963 `Delsplits [split_if]' or remove it in a specific call of the
  3964 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3965 other case splitting rules to/from the default simpset: every datatype
  3966 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3967 t is the name of the datatype).
  3968 
  3969 * Classical reasoner / Simplifier combination: new force_tac (and
  3970 derivatives Force_tac, force) combines rewriting and classical
  3971 reasoning (and whatever other tools) similarly to auto_tac, but is
  3972 aimed to solve the given subgoal completely.
  3973 
  3974 
  3975 *** General ***
  3976 
  3977 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3978 and `goalw': the theory is no longer needed as an explicit argument -
  3979 the current theory context is used; assumptions are no longer returned
  3980 at the ML-level unless one of them starts with ==> or !!; it is
  3981 recommended to convert to these new commands using isatool fixgoal
  3982 (backup your sources first!);
  3983 
  3984 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3985 the current theory context, and 'theory' to lookup stored theories;
  3986 
  3987 * new theory section 'locale' for declaring constants, assumptions and
  3988 definitions that have local scope;
  3989 
  3990 * new theory section 'nonterminals' for purely syntactic types;
  3991 
  3992 * new theory section 'setup' for generic ML setup functions
  3993 (e.g. package initialization);
  3994 
  3995 * the distribution now includes Isabelle icons: see
  3996 lib/logo/isabelle-{small,tiny}.xpm;
  3997 
  3998 * isatool install - install binaries with absolute references to
  3999 ISABELLE_HOME/bin;
  4000 
  4001 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4002 
  4003 * print mode 'emacs' reserved for Isamode;
  4004 
  4005 * support multiple print (ast) translations per constant name;
  4006 
  4007 * theorems involving oracles are now printed with a suffixed [!];
  4008 
  4009 
  4010 *** HOL ***
  4011 
  4012 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4013 
  4014 * HOL/inductive package reorganized and improved: now supports mutual
  4015 definitions such as
  4016 
  4017   inductive EVEN ODD
  4018     intrs
  4019       null "0 : EVEN"
  4020       oddI "n : EVEN ==> Suc n : ODD"
  4021       evenI "n : ODD ==> Suc n : EVEN"
  4022 
  4023 new theorem list "elims" contains an elimination rule for each of the
  4024 recursive sets; inductive definitions now handle disjunctive premises
  4025 correctly (also ZF);
  4026 
  4027 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4028 "mutual_induct" no longer exists - the induction rule is always
  4029 contained in "induct";
  4030 
  4031 
  4032 * HOL/datatype package re-implemented and greatly improved: now
  4033 supports mutually recursive datatypes such as
  4034 
  4035   datatype
  4036     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4037             | SUM ('a aexp) ('a aexp)
  4038             | DIFF ('a aexp) ('a aexp)
  4039             | NUM 'a
  4040   and
  4041     'a bexp = LESS ('a aexp) ('a aexp)
  4042             | AND ('a bexp) ('a bexp)
  4043             | OR ('a bexp) ('a bexp)
  4044 
  4045 as well as indirectly recursive datatypes such as
  4046 
  4047   datatype
  4048     ('a, 'b) term = Var 'a
  4049                   | App 'b ((('a, 'b) term) list)
  4050 
  4051 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4052 induction on mutually / indirectly recursive datatypes.
  4053 
  4054 Primrec equations are now stored in theory and can be accessed via
  4055 <function_name>.simps.
  4056 
  4057 INCOMPATIBILITIES:
  4058 
  4059   - Theories using datatypes must now have theory Datatype as an
  4060     ancestor.
  4061   - The specific <typename>.induct_tac no longer exists - use the
  4062     generic induct_tac instead.
  4063   - natE has been renamed to nat.exhaust - use exhaust_tac
  4064     instead of res_inst_tac ... natE. Note that the variable
  4065     names in nat.exhaust differ from the names in natE, this
  4066     may cause some "fragile" proofs to fail.
  4067   - The theorems split_<typename>_case and split_<typename>_case_asm
  4068     have been renamed to <typename>.split and <typename>.split_asm.
  4069   - Since default sorts of type variables are now handled correctly,
  4070     some datatype definitions may have to be annotated with explicit
  4071     sort constraints.
  4072   - Primrec definitions no longer require function name and type
  4073     of recursive argument.
  4074 
  4075 Consider using isatool fixdatatype to adapt your theories and proof
  4076 scripts to the new package (backup your sources first!).
  4077 
  4078 
  4079 * HOL/record package: considerably improved implementation; now
  4080 includes concrete syntax for record types, terms, updates; theorems
  4081 for surjective pairing and splitting !!-bound record variables; proof
  4082 support is as follows:
  4083 
  4084   1) standard conversions (selectors or updates applied to record
  4085 constructor terms) are part of the standard simpset;
  4086 
  4087   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4088 made part of standard simpset and claset via addIffs;
  4089 
  4090   3) a tactic for record field splitting (record_split_tac) is part of
  4091 the standard claset (addSWrapper);
  4092 
  4093 To get a better idea about these rules you may retrieve them via
  4094 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4095 the name of your record type.
  4096 
  4097 The split tactic 3) conceptually simplifies by the following rule:
  4098 
  4099   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4100 
  4101 Thus any record variable that is bound by meta-all will automatically
  4102 blow up into some record constructor term, consequently the
  4103 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4104 solve record problems automatically.
  4105 
  4106 
  4107 * reorganized the main HOL image: HOL/Integ and String loaded by
  4108 default; theory Main includes everything;
  4109 
  4110 * automatic simplification of integer sums and comparisons, using cancellation;
  4111 
  4112 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4113 
  4114 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4115 
  4116 * many new identities for unions, intersections, set difference, etc.;
  4117 
  4118 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4119 called split_if, split_split, split_sum_case and split_nat_case (to go
  4120 with add/delsplits);
  4121 
  4122 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4123 (?x::unit) = (); this is made part of the default simpset, which COULD
  4124 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4125 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4126 unit_abs_eta_conv is added in order to counter the effect of
  4127 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4128 %u.f();
  4129 
  4130 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4131 makes more sense);
  4132 
  4133 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4134   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4135   disjointness reasoning but breaking a few old proofs.
  4136 
  4137 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4138 to 'converse' from 'inverse' (for compatibility with ZF and some
  4139 literature);
  4140 
  4141 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4142 the well-founded relation;
  4143 
  4144 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4145     Compl A.  The "Compl" syntax remains available as input syntax for this
  4146     release ONLY.
  4147 
  4148 * HOL/Update: new theory of function updates:
  4149     f(a:=b) == %x. if x=a then b else f x
  4150 may also be iterated as in f(a:=b,c:=d,...);
  4151 
  4152 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4153 
  4154 * HOL/List:
  4155   - new function list_update written xs[i:=v] that updates the i-th
  4156     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4157   - new function `upt' written [i..j(] which generates the list
  4158     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4159     bound write [i..j], which is a shorthand for [i..j+1(].
  4160   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4161 
  4162 * HOL/Arith:
  4163   - removed 'pred' (predecessor) function;
  4164   - generalized some theorems about n-1;
  4165   - many new laws about "div" and "mod";
  4166   - new laws about greatest common divisors (see theory ex/Primes);
  4167 
  4168 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4169 instead of "inverse";
  4170 
  4171 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4172   of the multiset ordering;
  4173 
  4174 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4175   (not included by default);
  4176 
  4177 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4178 
  4179 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4180   programs, i.e. different program variables may have different types.
  4181 
  4182 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4183   [previously, this check worked only if the rewrite rule was unconditional]
  4184   Now rew can involve either definitions or equalities (either == or =).
  4185 
  4186 
  4187 *** ZF ***
  4188 
  4189 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4190   only the theorems proved on ZF.ML;
  4191 
  4192 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4193   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4194   disjointness reasoning but breaking a few old proofs.
  4195 
  4196 * ZF/Update: new theory of function updates
  4197     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4198   may also be iterated as in f(a:=b,c:=d,...);
  4199 
  4200 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4201 
  4202 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4203   [previously, this check worked only if the rewrite rule was unconditional]
  4204   Now rew can involve either definitions or equalities (either == or =).
  4205 
  4206 * case_tac provided for compatibility with HOL
  4207     (like the old excluded_middle_tac, but with subgoals swapped)
  4208 
  4209 
  4210 *** Internal programming interfaces ***
  4211 
  4212 * Pure: several new basic modules made available for general use, see
  4213 also src/Pure/README;
  4214 
  4215 * improved the theory data mechanism to support encapsulation (data
  4216 kind name replaced by private Object.kind, acting as authorization
  4217 key); new type-safe user interface via functor TheoryDataFun; generic
  4218 print_data function becomes basically useless;
  4219 
  4220 * removed global_names compatibility flag -- all theory declarations
  4221 are qualified by default;
  4222 
  4223 * module Pure/Syntax now offers quote / antiquote translation
  4224 functions (useful for Hoare logic etc. with implicit dependencies);
  4225 see HOL/ex/Antiquote for an example use;
  4226 
  4227 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4228 cterm -> thm;
  4229 
  4230 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4231 subgoal;
  4232 
  4233 * Display.print_goals function moved to Locale.print_goals;
  4234 
  4235 * standard print function for goals supports current_goals_markers
  4236 variable for marking begin of proof, end of proof, start of goal; the
  4237 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4238 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4239 for example;
  4240 
  4241 
  4242 
  4243 New in Isabelle98 (January 1998)
  4244 --------------------------------
  4245 
  4246 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4247 
  4248 * changed lexical syntax of terms / types: dots made part of long
  4249 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4250 
  4251 * simpset (and claset) reference variable replaced by functions
  4252 simpset / simpset_ref;
  4253 
  4254 * no longer supports theory aliases (via merge) and non-trivial
  4255 implicit merge of thms' signatures;
  4256 
  4257 * most internal names of constants changed due to qualified names;
  4258 
  4259 * changed Pure/Sequence interface (see Pure/seq.ML);
  4260 
  4261 
  4262 *** General Changes ***
  4263 
  4264 * hierachically structured name spaces (for consts, types, axms, thms
  4265 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4266 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4267 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4268 long_names for fully qualified output names; NOTE: ML programs
  4269 (special tactics, packages etc.) referring to internal names may have
  4270 to be adapted to cope with fully qualified names; in case of severe
  4271 backward campatibility problems try setting 'global_names' at compile
  4272 time to have enrything declared within a flat name space; one may also
  4273 fine tune name declarations in theories via the 'global' and 'local'
  4274 section;
  4275 
  4276 * reimplemented the implicit simpset and claset using the new anytype
  4277 data filed in signatures; references simpset:simpset ref etc. are
  4278 replaced by functions simpset:unit->simpset and
  4279 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4280 to patch your ML files accordingly;
  4281 
  4282 * HTML output now includes theory graph data for display with Java
  4283 applet or isatool browser; data generated automatically via isatool
  4284 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4285 
  4286 * defs may now be conditional; improved rewrite_goals_tac to handle
  4287 conditional equations;
  4288 
  4289 * defs now admits additional type arguments, using TYPE('a) syntax;
  4290 
  4291 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4292 creates a new theory node; implicit merge of thms' signatures is
  4293 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4294 transfer:theory->thm->thm in (rare) cases;
  4295 
  4296 * improved handling of draft signatures / theories; draft thms (and
  4297 ctyps, cterms) are automatically promoted to real ones;
  4298 
  4299 * slightly changed interfaces for oracles: admit many per theory, named
  4300 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4301 
  4302 * print_goals: optional output of const types (set show_consts and
  4303 show_types);
  4304 
  4305 * improved output of warnings (###) and errors (***);
  4306 
  4307 * subgoal_tac displays a warning if the new subgoal has type variables;
  4308 
  4309 * removed old README and Makefiles;
  4310 
  4311 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4312 
  4313 * removed obsolete init_pps and init_database;
  4314 
  4315 * deleted the obsolete tactical STATE, which was declared by
  4316     fun STATE tacfun st = tacfun st st;
  4317 
  4318 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4319 (which abbreviates $HOME);
  4320 
  4321 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4322 use isatool fixseq to adapt your ML programs (this works for fully
  4323 qualified references to the Sequence structure only!);
  4324 
  4325 * use_thy no longer requires writable current directory; it always
  4326 reloads .ML *and* .thy file, if either one is out of date;
  4327 
  4328 
  4329 *** Classical Reasoner ***
  4330 
  4331 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4332 tactics that use classical reasoning to simplify a subgoal without
  4333 splitting it into several subgoals;
  4334 
  4335 * Safe_tac: like safe_tac but uses the default claset;
  4336 
  4337 
  4338 *** Simplifier ***
  4339 
  4340 * added simplification meta rules:
  4341     (asm_)(full_)simplify: simpset -> thm -> thm;
  4342 
  4343 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4344 logics (again);
  4345 
  4346 * added prems argument to simplification procedures;
  4347 
  4348 * HOL, FOL, ZF: added infix function `addsplits':
  4349   instead of `<simpset> setloop (split_tac <thms>)'
  4350   you can simply write `<simpset> addsplits <thms>'
  4351 
  4352 
  4353 *** Syntax ***
  4354 
  4355 * TYPE('a) syntax for type reflection terms;
  4356 
  4357 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4358 
  4359 * pretty printer: changed order of mixfix annotation preference (again!);
  4360 
  4361 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4362 
  4363 
  4364 *** HOL ***
  4365 
  4366 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4367   with `addloop' of the simplifier to faciliate case splitting in premises.
  4368 
  4369 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4370 
  4371 * HOL/Auth: new protocol proofs including some for the Internet
  4372   protocol TLS;
  4373 
  4374 * HOL/Map: new theory of `maps' a la VDM;
  4375 
  4376 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4377 cancelling out common nat summands from =, <, <= (in)equalities, or
  4378 differences; simplification procedures nat_cancel_factor for
  4379 cancelling common factor from =, <, <= (in)equalities over natural
  4380 sums; nat_cancel contains both kinds of procedures, it is installed by
  4381 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4382 
  4383 * HOL/simplifier: terms of the form
  4384   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4385   are rewritten to
  4386   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4387   and those of the form
  4388   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4389   are rewritten to
  4390   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4391 
  4392 * HOL/datatype
  4393   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4394 
  4395   P(t_case f1 ... fn x) =
  4396      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4397         ...
  4398        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4399      )
  4400 
  4401   and a theorem `split_t_case_asm' of the form
  4402 
  4403   P(t_case f1 ... fn x) =
  4404     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4405         ...
  4406        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4407      )
  4408   which can be added to a simpset via `addsplits'. The existing theorems
  4409   expand_list_case and expand_option_case have been renamed to
  4410   split_list_case and split_option_case.
  4411 
  4412 * HOL/Arithmetic:
  4413   - `pred n' is automatically converted to `n-1'.
  4414     Users are strongly encouraged not to use `pred' any longer,
  4415     because it will disappear altogether at some point.
  4416   - Users are strongly encouraged to write "0 < n" rather than
  4417     "n ~= 0". Theorems and proof tools have been modified towards this
  4418     `standard'.
  4419 
  4420 * HOL/Lists:
  4421   the function "set_of_list" has been renamed "set" (and its theorems too);
  4422   the function "nth" now takes its arguments in the reverse order and
  4423   has acquired the infix notation "!" as in "xs!n".
  4424 
  4425 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4426 
  4427 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4428   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4429 
  4430 * HOL/record: extensible records with schematic structural subtyping
  4431 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4432 still lacks various theorems and concrete record syntax;
  4433 
  4434 
  4435 *** HOLCF ***
  4436 
  4437 * removed "axioms" and "generated by" sections;
  4438 
  4439 * replaced "ops" section by extended "consts" section, which is capable of
  4440   handling the continuous function space "->" directly;
  4441 
  4442 * domain package:
  4443   . proves theorems immediately and stores them in the theory,
  4444   . creates hierachical name space,
  4445   . now uses normal mixfix annotations (instead of cinfix...),
  4446   . minor changes to some names and values (for consistency),
  4447   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4448   . separator between mutual domain defs: changed "," to "and",
  4449   . improved handling of sort constraints;  now they have to
  4450     appear on the left-hand side of the equations only;
  4451 
  4452 * fixed LAM <x,y,zs>.b syntax;
  4453 
  4454 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4455 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4456 
  4457 
  4458 *** FOL and ZF ***
  4459 
  4460 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4461   with `addloop' of the simplifier to faciliate case splitting in premises.
  4462 
  4463 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4464 in HOL, they strip ALL and --> from proved theorems;
  4465 
  4466 
  4467 
  4468 New in Isabelle94-8 (May 1997)
  4469 ------------------------------
  4470 
  4471 *** General Changes ***
  4472 
  4473 * new utilities to build / run / maintain Isabelle etc. (in parts
  4474 still somewhat experimental); old Makefiles etc. still functional;
  4475 
  4476 * new 'Isabelle System Manual';
  4477 
  4478 * INSTALL text, together with ./configure and ./build scripts;
  4479 
  4480 * reimplemented type inference for greater efficiency, better error
  4481 messages and clean internal interface;
  4482 
  4483 * prlim command for dealing with lots of subgoals (an easier way of
  4484 setting goals_limit);
  4485 
  4486 
  4487 *** Syntax ***
  4488 
  4489 * supports alternative (named) syntax tables (parser and pretty
  4490 printer); internal interface is provided by add_modesyntax(_i);
  4491 
  4492 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4493 be used in conjunction with the Isabelle symbol font; uses the
  4494 "symbols" syntax table;
  4495 
  4496 * added token_translation interface (may translate name tokens in
  4497 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4498 the current print_mode); IMPORTANT: user print translation functions
  4499 are responsible for marking newly introduced bounds
  4500 (Syntax.mark_boundT);
  4501 
  4502 * token translations for modes "xterm" and "xterm_color" that display
  4503 names in bold, underline etc. or colors (which requires a color
  4504 version of xterm);
  4505 
  4506 * infixes may now be declared with names independent of their syntax;
  4507 
  4508 * added typed_print_translation (like print_translation, but may
  4509 access type of constant);
  4510 
  4511 
  4512 *** Classical Reasoner ***
  4513 
  4514 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4515 some limitations.  Blast_tac...
  4516   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4517   + ignores elimination rules that don't have the correct format
  4518         (the conclusion MUST be a formula variable)
  4519   + ignores types, which can make HOL proofs fail
  4520   + rules must not require higher-order unification, e.g. apply_type in ZF
  4521     [message "Function Var's argument not a bound variable" relates to this]
  4522   + its proof strategy is more general but can actually be slower
  4523 
  4524 * substitution with equality assumptions no longer permutes other
  4525 assumptions;
  4526 
  4527 * minor changes in semantics of addafter (now called addaltern); renamed
  4528 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4529 (and access functions for it);
  4530 
  4531 * improved combination of classical reasoner and simplifier:
  4532   + functions for handling clasimpsets
  4533   + improvement of addss: now the simplifier is called _after_ the
  4534     safe steps.
  4535   + safe variant of addss called addSss: uses safe simplifications
  4536     _during_ the safe steps. It is more complete as it allows multiple
  4537     instantiations of unknowns (e.g. with slow_tac).
  4538 
  4539 *** Simplifier ***
  4540 
  4541 * added interface for simplification procedures (functions that
  4542 produce *proven* rewrite rules on the fly, depending on current
  4543 redex);
  4544 
  4545 * ordering on terms as parameter (used for ordered rewriting);
  4546 
  4547 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4548 
  4549 * the solver is now split into a safe and an unsafe part.
  4550 This should be invisible for the normal user, except that the
  4551 functions setsolver and addsolver have been renamed to setSolver and
  4552 addSolver; added safe_asm_full_simp_tac;
  4553 
  4554 
  4555 *** HOL ***
  4556 
  4557 * a generic induction tactic `induct_tac' which works for all datatypes and
  4558 also for type `nat';
  4559 
  4560 * a generic case distinction tactic `exhaust_tac' which works for all
  4561 datatypes and also for type `nat';
  4562 
  4563 * each datatype comes with a function `size';
  4564 
  4565 * patterns in case expressions allow tuple patterns as arguments to
  4566 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4567 
  4568 * primrec now also works with type nat;
  4569 
  4570 * recdef: a new declaration form, allows general recursive functions to be
  4571 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4572 
  4573 * the constant for negation has been renamed from "not" to "Not" to
  4574 harmonize with FOL, ZF, LK, etc.;
  4575 
  4576 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4577 infinite lists;
  4578 
  4579 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4580 
  4581 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4582 problems in commutative rings, using axiomatic type classes for + and *;
  4583 
  4584 * more examples in HOL/MiniML and HOL/Auth;
  4585 
  4586 * more default rewrite rules for quantifiers, union/intersection;
  4587 
  4588 * a new constant `arbitrary == @x.False';
  4589 
  4590 * HOLCF/IOA replaces old HOL/IOA;
  4591 
  4592 * HOLCF changes: derived all rules and arities
  4593   + axiomatic type classes instead of classes
  4594   + typedef instead of faking type definitions
  4595   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4596   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4597   + eliminated the types void, one, tr
  4598   + use unit lift and bool lift (with translations) instead of one and tr
  4599   + eliminated blift from Lift3.thy (use Def instead of blift)
  4600   all eliminated rules are derived as theorems --> no visible changes ;
  4601 
  4602 
  4603 *** ZF ***
  4604 
  4605 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4606 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4607 as ZF_cs addSIs [equalityI];
  4608 
  4609 
  4610 
  4611 New in Isabelle94-7 (November 96)
  4612 ---------------------------------
  4613 
  4614 * allowing negative levels (as offsets) in prlev and choplev;
  4615 
  4616 * super-linear speedup for large simplifications;
  4617 
  4618 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4619 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4620 FAIL); can suppress it using the command Delsimps (ex_simps @
  4621 all_simps); De Morgan laws are also now included, by default;
  4622 
  4623 * improved printing of ==>  :  ~:
  4624 
  4625 * new object-logic "Sequents" adds linear logic, while replacing LK
  4626 and Modal (thanks to Sara Kalvala);
  4627 
  4628 * HOL/Auth: correctness proofs for authentication protocols;
  4629 
  4630 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4631 examples on HOL/Auth);
  4632 
  4633 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4634 the rewriter and classical reasoner simultaneously;
  4635 
  4636 * function uresult no longer returns theorems in "standard" format;
  4637 regain previous version by: val uresult = standard o uresult;
  4638 
  4639 
  4640 
  4641 New in Isabelle94-6
  4642 -------------------
  4643 
  4644 * oracles -- these establish an interface between Isabelle and trusted
  4645 external reasoners, which may deliver results as theorems;
  4646 
  4647 * proof objects (in particular record all uses of oracles);
  4648 
  4649 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4650 
  4651 * "constdefs" section in theory files;
  4652 
  4653 * "primrec" section (HOL) no longer requires names;
  4654 
  4655 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4656 
  4657 
  4658 
  4659 New in Isabelle94-5
  4660 -------------------
  4661 
  4662 * reduced space requirements;
  4663 
  4664 * automatic HTML generation from theories;
  4665 
  4666 * theory files no longer require "..." (quotes) around most types;
  4667 
  4668 * new examples, including two proofs of the Church-Rosser theorem;
  4669 
  4670 * non-curried (1994) version of HOL is no longer distributed;
  4671 
  4672 
  4673 
  4674 New in Isabelle94-4
  4675 -------------------
  4676 
  4677 * greatly reduced space requirements;
  4678 
  4679 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4680 
  4681 * searchable theorem database (see the section "Retrieving theorems" on
  4682 page 8 of the Reference Manual);
  4683 
  4684 * new examples, including Grabczewski's monumental case study of the
  4685 Axiom of Choice;
  4686 
  4687 * The previous version of HOL renamed to Old_HOL;
  4688 
  4689 * The new version of HOL (previously called CHOL) uses a curried syntax
  4690 for functions.  Application looks like f a b instead of f(a,b);
  4691 
  4692 * Mutually recursive inductive definitions finally work in HOL;
  4693 
  4694 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4695 translates to the operator "split";
  4696 
  4697 
  4698 
  4699 New in Isabelle94-3
  4700 -------------------
  4701 
  4702 * new infix operator, addss, allowing the classical reasoner to
  4703 perform simplification at each step of its search.  Example:
  4704         fast_tac (cs addss ss)
  4705 
  4706 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4707 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4708 look like (a,b) instead of <a,b>;
  4709 
  4710 * PLEASE NOTE: CHOL will eventually replace HOL!
  4711 
  4712 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4713 It translates to the operator "split".  A new theory of integers is available;
  4714 
  4715 * In ZF, integer numerals now denote two's-complement binary integers.
  4716 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4717 
  4718 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4719 of the Axiom of Choice;
  4720 
  4721 
  4722 
  4723 New in Isabelle94-2
  4724 -------------------
  4725 
  4726 * Significantly faster resolution;
  4727 
  4728 * the different sections in a .thy file can now be mixed and repeated
  4729 freely;
  4730 
  4731 * Database of theorems for FOL, HOL and ZF.  New
  4732 commands including qed, qed_goal and bind_thm store theorems in the database.
  4733 
  4734 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4735 a given theory (thms_of), or find out what theory a theorem was proved in
  4736 (theory_of_thm);
  4737 
  4738 * Bugs fixed in the inductive definition and datatype packages;
  4739 
  4740 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4741 and HOL_dup_cs obsolete;
  4742 
  4743 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4744 have been removed;
  4745 
  4746 * Simpler definition of function space in ZF;
  4747 
  4748 * new results about cardinal and ordinal arithmetic in ZF;
  4749 
  4750 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4751 types;
  4752 
  4753 
  4754 $Id$