NEWS
author nipkow
Sun Jun 10 10:23:42 2007 +0200 (2007-06-10)
changeset 23300 b785068bd5dc
parent 23295 86e225406859
child 23367 05f399115ba5
permissions -rw-r--r--
*** empty log message ***
     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': supports "*" 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 * Method "algebra" solves polynomial equations over (semi)rings using
   534   Groebner bases. The (semi)ring structure is defined by locales and
   535   the tool setup depends on that generic context. Installing the
   536   method for a specific type involves instantiating the locale and
   537   possibly adding declarations for computation on the coefficients.
   538   The method is already instantiated for natural numbers and for the
   539   axiomatic class of idoms with numerals.  See also the paper by
   540   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   541   underlying this architecture of context-aware proof-tools.
   542 
   543 * constant "List.op @" now named "List.append".  Use ML antiquotations
   544 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   545 possible incompatibilities when working on ML level.
   546 
   547 * Constant renames due to introduction of canonical name prefixing for
   548   class package:
   549 
   550     HOL.abs ~> HOL.minus_class.abs
   551     HOL.divide ~> HOL.divide_class.divide
   552     Nat.power ~> Nat.power_class.power
   553     Nat.size ~> Nat.size_class.size
   554     Numeral.number_of ~> Numeral.number_class.number_of
   555     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   556 
   557 * Rudimentary class target mechanism involves constant renames:
   558 
   559     Orderings.min ~> Orderings.ord_class.min
   560     Orderings.max ~> Orderings.ord_class.max
   561     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   562 
   563 * case expressions and primrec: missing cases now mapped to "undefined"
   564 instead of "arbitrary"
   565 
   566 * new constant "undefined" with axiom "undefined x = undefined"
   567 
   568 * new class "default" with associated constant "default"
   569 
   570 * new function listsum :: 'a list => 'a for arbitrary monoids.
   571   Special syntax: "SUM x <- xs. f x" (and latex variants)
   572 
   573 * new (input only) syntax for Haskell-like list comprehension, eg
   574   [(x,y). x <- xs, y <- ys, x ~= y]
   575   For details see List.thy.
   576 
   577 * The special syntax for function "filter" has changed from [x : xs. P] to
   578   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   579   and for uniformity. INCOMPATIBILITY
   580 
   581 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   582     when generating code.
   583 
   584 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   585     when generating code.
   586 
   587 * Library/Commutative_Ring.thy: switched from recdef to function package;
   588     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   589 
   590 * Some steps towards more uniform lattice theory development in HOL.
   591 
   592     constants "meet" and "join" now named "inf" and "sup"
   593     constant "Meet" now named "Inf"
   594 
   595     classes "meet_semilorder" and "join_semilorder" now named
   596       "lower_semilattice" and "upper_semilattice"
   597     class "lorder" now named "lattice"
   598     class "comp_lat" now named "complete_lattice"
   599 
   600     Instantiation of lattice classes allows explicit definitions
   601     for "inf" and "sup" operations.
   602 
   603   INCOMPATIBILITY.  Theorem renames:
   604 
   605     meet_left_le            ~> inf_le1
   606     meet_right_le           ~> inf_le2
   607     join_left_le            ~> sup_ge1
   608     join_right_le           ~> sup_ge2
   609     meet_join_le            ~> inf_sup_ord
   610     le_meetI                ~> le_infI
   611     join_leI                ~> le_supI
   612     le_meet                 ~> le_inf_iff
   613     le_join                 ~> ge_sup_conv
   614     meet_idempotent         ~> inf_idem
   615     join_idempotent         ~> sup_idem
   616     meet_comm               ~> inf_commute
   617     join_comm               ~> sup_commute
   618     meet_leI1               ~> le_infI1
   619     meet_leI2               ~> le_infI2
   620     le_joinI1               ~> le_supI1
   621     le_joinI2               ~> le_supI2
   622     meet_assoc              ~> inf_assoc
   623     join_assoc              ~> sup_assoc
   624     meet_left_comm          ~> inf_left_commute
   625     meet_left_idempotent    ~> inf_left_idem
   626     join_left_comm          ~> sup_left_commute
   627     join_left_idempotent    ~> sup_left_idem
   628     meet_aci                ~> inf_aci
   629     join_aci                ~> sup_aci
   630     le_def_meet             ~> le_iff_inf
   631     le_def_join             ~> le_iff_sup
   632     join_absorp2            ~> sup_absorb2
   633     join_absorp1            ~> sup_absorb1
   634     meet_absorp1            ~> inf_absorb1
   635     meet_absorp2            ~> inf_absorb2
   636     meet_join_absorp        ~> inf_sup_absorb
   637     join_meet_absorp        ~> sup_inf_absorb
   638     distrib_join_le         ~> distrib_sup_le
   639     distrib_meet_le         ~> distrib_inf_le
   640 
   641     add_meet_distrib_left   ~> add_inf_distrib_left
   642     add_join_distrib_left   ~> add_sup_distrib_left
   643     is_join_neg_meet        ~> is_join_neg_inf
   644     is_meet_neg_join        ~> is_meet_neg_sup
   645     add_meet_distrib_right  ~> add_inf_distrib_right
   646     add_join_distrib_right  ~> add_sup_distrib_right
   647     add_meet_join_distribs  ~> add_sup_inf_distribs
   648     join_eq_neg_meet        ~> sup_eq_neg_inf
   649     meet_eq_neg_join        ~> inf_eq_neg_sup
   650     add_eq_meet_join        ~> add_eq_inf_sup
   651     meet_0_imp_0            ~> inf_0_imp_0
   652     join_0_imp_0            ~> sup_0_imp_0
   653     meet_0_eq_0             ~> inf_0_eq_0
   654     join_0_eq_0             ~> sup_0_eq_0
   655     neg_meet_eq_join        ~> neg_inf_eq_sup
   656     neg_join_eq_meet        ~> neg_sup_eq_inf
   657     join_eq_if              ~> sup_eq_if
   658 
   659     mono_meet               ~> mono_inf
   660     mono_join               ~> mono_sup
   661     meet_bool_eq            ~> inf_bool_eq
   662     join_bool_eq            ~> sup_bool_eq
   663     meet_fun_eq             ~> inf_fun_eq
   664     join_fun_eq             ~> sup_fun_eq
   665     meet_set_eq             ~> inf_set_eq
   666     join_set_eq             ~> sup_set_eq
   667     meet1_iff               ~> inf1_iff
   668     meet2_iff               ~> inf2_iff
   669     meet1I                  ~> inf1I
   670     meet2I                  ~> inf2I
   671     meet1D1                 ~> inf1D1
   672     meet2D1                 ~> inf2D1
   673     meet1D2                 ~> inf1D2
   674     meet2D2                 ~> inf2D2
   675     meet1E                  ~> inf1E
   676     meet2E                  ~> inf2E
   677     join1_iff               ~> sup1_iff
   678     join2_iff               ~> sup2_iff
   679     join1I1                 ~> sup1I1
   680     join2I1                 ~> sup2I1
   681     join1I1                 ~> sup1I1
   682     join2I2                 ~> sup1I2
   683     join1CI                 ~> sup1CI
   684     join2CI                 ~> sup2CI
   685     join1E                  ~> sup1E
   686     join2E                  ~> sup2E
   687 
   688     is_meet_Meet            ~> is_meet_Inf
   689     Meet_bool_def           ~> Inf_bool_def
   690     Meet_fun_def            ~> Inf_fun_def
   691     Meet_greatest           ~> Inf_greatest
   692     Meet_lower              ~> Inf_lower
   693     Meet_set_def            ~> Inf_set_def
   694 
   695     listsp_meetI            ~> listsp_infI
   696     listsp_meet_eq          ~> listsp_inf_eq
   697 
   698     meet_min                ~> inf_min
   699     join_max                ~> sup_max
   700 
   701 * Classes "order" and "linorder": facts "refl", "trans" and
   702 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   703 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   704 
   705 * Classes "order" and "linorder": 
   706 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   707 proofs changed.
   708 
   709 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   710 INCOMPATIBILITY.
   711 
   712 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   713 INCOMPATIBILITY.
   714 
   715 * Added syntactic class "size"; overloaded constant "size" now has
   716 type "'a::size ==> bool"
   717 
   718 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   719 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   720 
   721 * Added method "lexicographic_order" automatically synthesizes
   722 termination relations as lexicographic combinations of size measures
   723 -- 'function' package.
   724 
   725 * HOL/records: generalised field-update to take a function on the
   726 field rather than the new value: r(|A := x|) is translated to A_update
   727 (K x) r The K-combinator that is internally used is called K_record.
   728 INCOMPATIBILITY: Usage of the plain update functions has to be
   729 adapted.
   730  
   731 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   732 0 * x = 0, which are required for a semiring.  Richer structures do
   733 not inherit from semiring_0 anymore, because this property is a
   734 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   735 semiring_0, there is more to prove, but this is mostly trivial.
   736 
   737 * axclass "recpower" was generalized to arbitrary monoids, not just
   738 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   739 commutativity or a semiring property, add the corresponding classes.
   740 
   741 * Unified locale partial_order with class definition (cf. theory
   742 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   743 
   744 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   745 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   746 Isar level, use abbreviations instead.
   747 
   748 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   749 rarely occuring name references (e.g. ``List.op mem.simps'') require
   750 renaming (e.g. ``List.memberl.simps'').
   751 
   752 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   753 INCOMPATIBILITY.
   754 
   755 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   756 
   757 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   758 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   759 significant changes for setting up numeral syntax for types:
   760 
   761   - new constants Numeral.pred and Numeral.succ instead
   762       of former Numeral.bin_pred and Numeral.bin_succ.
   763   - Use integer operations instead of bin_add, bin_mult and so on.
   764   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   765   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   766 
   767 See HOL/Integ/IntArith.thy for an example setup.
   768 
   769 * New top level command 'normal_form' computes the normal form of a
   770 term that may contain free variables. For example ``normal_form
   771 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   772 suitable for heavy-duty computations because the functions are
   773 compiled to ML first.
   774 
   775 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   776 25 like -->); output depends on the "iff" print_mode, the default is
   777 "A = B" (with priority 50).
   778 
   779 * Renamed constants in HOL.thy and Orderings.thy:
   780     op +   ~> HOL.plus_class.plus
   781     op -   ~> HOL.minus_class.minus
   782     uminus ~> HOL.minus_class.uminus
   783     op *   ~> HOL.times_class.times
   784     op <   ~> Orderings.ord_class.less
   785     op <=  ~> Orderings.ord_class.less_eq
   786 
   787 Adaptions may be required in the following cases:
   788 
   789 a) User-defined constants using any of the names "plus", "minus", "times",
   790 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   791 may go wrong.
   792 INCOMPATIBILITY: use more specific names.
   793 
   794 b) Variables named "plus", "minus", "times", "less", "less_eq"
   795 INCOMPATIBILITY: use more specific names.
   796 
   797 c) Permutative equations (e.g. "a + b = b + a")
   798 Since the change of names also changes the order of terms, permutative
   799 rewrite rules may get applied in a different order. Experience shows that
   800 this is rarely the case (only two adaptions in the whole Isabelle
   801 distribution).
   802 INCOMPATIBILITY: rewrite proofs
   803 
   804 d) ML code directly refering to constant names
   805 This in general only affects hand-written proof tactics, simprocs and so on.
   806 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   807 of const_name ML antiquotations.
   808 
   809 * Relations less (<) and less_eq (<=) are also available on type bool.
   810 Modified syntax to disallow nesting without explicit parentheses,
   811 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   812 
   813 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   814 
   815 * Relation composition operator "op O" now has precedence 75 and binds
   816 stronger than union and intersection. INCOMPATIBILITY.
   817 
   818 * The old set interval syntax "{m..n(}" (and relatives) has been
   819 removed.  Use "{m..<n}" (and relatives) instead.
   820 
   821 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   822 "t = s" to False (by simproc "neq_simproc").  For backward
   823 compatibility this can be disabled by ML "reset use_neq_simproc".
   824 
   825 * "m dvd n" where m and n are numbers is evaluated to True/False by
   826 simp.
   827 
   828 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   829 
   830 * Theorem setsum_mult renamed to setsum_right_distrib.
   831 
   832 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   833 ``rule'' method.
   834 
   835 * Reimplemented methods ``sat'' and ``satx'', with several
   836 improvements: goals no longer need to be stated as "<prems> ==>
   837 False", equivalences (i.e. "=" on type bool) are handled, variable
   838 names of the form "lit_<n>" are no longer reserved, significant
   839 speedup.
   840 
   841 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   842 zChaff is still supported as well.
   843 
   844 * 'inductive' and 'datatype': provide projections of mutual rules,
   845 bundled as foo_bar.inducts;
   846 
   847 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   848 Library.
   849 
   850 * Library: moved theory Accessible_Part to main HOL.
   851 
   852 * Library: added theory Coinductive_List of potentially infinite lists
   853 as greatest fixed-point.
   854 
   855 * Library: added theory AssocList which implements (finite) maps as
   856 association lists.
   857 
   858 * Added proof method ``evaluation'' for efficiently solving a goal
   859 (i.e. a boolean expression) by compiling it to ML. The goal is
   860 "proved" (via an oracle) if it evaluates to True.
   861 
   862 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   863 also when invoked by the simplifier.  This results in the simplifier
   864 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   865 fast_arith_split_limit to 0 to obtain the old behavior.
   866 
   867 * Support for hex (0x20) and binary (0b1001) numerals.
   868 
   869 * New method: reify eqs (t), where eqs are equations for an
   870 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   871 parameter, computes a term s::'b and a list xs::'a list and proves the
   872 theorem I xs s = t. This is also known as reification or quoting. The
   873 resulting theorem is applied to the subgoal to substitute t with I xs
   874 s.  If t is omitted, the subgoal itself is reified.
   875 
   876 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   877 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   878 where f is supposed to be a computable function (in the sense of code
   879 generattion). The method uses reify to compute s and xs as above then
   880 applies corr_thm and uses normalization by evaluation to "prove" f s =
   881 r and finally gets the theorem t = r, which is again applied to the
   882 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   883 
   884 * Reflection: Automatic refification now handels binding, an example
   885 is available in HOL/ex/ReflectionEx.thy
   886 
   887 
   888 *** HOL-Algebra ***
   889 
   890 * Formalisation of ideals and the quotient construction over rings.
   891 
   892 * Order and lattice theory no longer based on records.
   893 INCOMPATIBILITY.
   894 
   895 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   896 greatest_closed.  INCOMPATIBILITY.
   897 
   898 * Method algebra is now set up via an attribute.  For examples see
   899 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   900 of algebraic structures.
   901 
   902 * Renamed theory CRing to Ring.
   903 
   904 
   905 *** HOL-Complex ***
   906 
   907 * Theory Real: new method ferrack implements quantifier elimination
   908 for linear arithmetic over the reals. The quantifier elimination
   909 feature is used only for decision, for compatibility with arith. This
   910 means a goal is either solved or left unchanged, no simplification.
   911 
   912 * Hyperreal: Functions root and sqrt are now defined on negative real
   913 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   914 Nonnegativity side conditions have been removed from many lemmas, so
   915 that more subgoals may now be solved by simplification; potential
   916 INCOMPATIBILITY.
   917 
   918 * Real: New axiomatic classes formalize real normed vector spaces and
   919 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   920 and norm :: 'a => real.
   921 
   922 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   923 from reals into other types. The overloaded constant Reals :: 'a set
   924 is now defined as range of_real; potential INCOMPATIBILITY.
   925 
   926 * Real: ML code generation is supported now and hence also quickcheck.
   927 Reals are implemented as arbitrary precision rationals.
   928 
   929 * Hyperreal: Several constants that previously worked only for the
   930 reals have been generalized, so they now work over arbitrary vector
   931 spaces. Type annotations may need to be added in some cases; potential
   932 INCOMPATIBILITY.
   933 
   934   Infinitesimal  :: ('a::real_normed_vector) star set
   935   HFinite        :: ('a::real_normed_vector) star set
   936   HInfinite      :: ('a::real_normed_vector) star set
   937   approx         :: ('a::real_normed_vector) star => 'a star => bool
   938   monad          :: ('a::real_normed_vector) star => 'a star set
   939   galaxy         :: ('a::real_normed_vector) star => 'a star set
   940   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   941   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   942   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   943   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   944   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   945   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   946   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   947   sgn            :: 'a::real_normed_vector => 'a
   948   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   949 
   950 * Complex: Some complex-specific constants are now abbreviations for
   951 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   952 hnorm.  Other constants have been entirely removed in favor of the
   953 polymorphic versions (INCOMPATIBILITY):
   954 
   955   approx        <-- capprox
   956   HFinite       <-- CFinite
   957   HInfinite     <-- CInfinite
   958   Infinitesimal <-- CInfinitesimal
   959   monad         <-- cmonad
   960   galaxy        <-- cgalaxy
   961   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   962   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   963   (ns)deriv     <-- (ns)cderiv
   964 
   965 
   966 *** ML ***
   967 
   968 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
   969 
   970 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   971 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   972 init only required for impure data.  INCOMPATIBILITY: empty really
   973 need to be empty (no dependencies on theory content!)
   974 
   975 * ML within Isar: antiquotations allow to embed statically-checked
   976 formal entities in the source, referring to the context available at
   977 compile-time.  For example:
   978 
   979 ML {* @{typ "'a => 'b"} *}
   980 ML {* @{term "%x. x"} *}
   981 ML {* @{prop "x == y"} *}
   982 ML {* @{ctyp "'a => 'b"} *}
   983 ML {* @{cterm "%x. x"} *}
   984 ML {* @{cprop "x == y"} *}
   985 ML {* @{thm asm_rl} *}
   986 ML {* @{thms asm_rl} *}
   987 ML {* @{const_name c} *}
   988 ML {* @{const_syntax c} *}
   989 ML {* @{context} *}
   990 ML {* @{theory} *}
   991 ML {* @{theory Pure} *}
   992 ML {* @{simpset} *}
   993 ML {* @{claset} *}
   994 ML {* @{clasimpset} *}
   995 
   996 The same works for sources being ``used'' within an Isar context.
   997 
   998 * ML in Isar: improved error reporting; extra verbosity with
   999 Toplevel.debug enabled.
  1000 
  1001 * Pure/library:
  1002 
  1003   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1004   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1005 
  1006 The semantics of "burrow" is: "take a function with *simulatanously*
  1007 transforms a list of value, and apply it *simulatanously* to a list of
  1008 list of values of the appropriate type". Compare this with "map" which
  1009 would *not* apply its argument function simulatanously but in
  1010 sequence; "fold_burrow" has an additional context.
  1011 
  1012 * Pure/library: functions map2 and fold2 with curried syntax for
  1013 simultanous mapping and folding:
  1014 
  1015     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1016     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1017 
  1018 * Pure/library: indexed lists - some functions in the Isabelle library
  1019 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1020 given more convenient names and signatures reminiscent of similar
  1021 functions for alists, tables, etc:
  1022 
  1023   val nth: 'a list -> int -> 'a 
  1024   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1025   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1026 
  1027 Note that fold_index starts counting at index 0, not 1 like foldln
  1028 used to.
  1029 
  1030 * Pure/library: added general ``divide_and_conquer'' combinator on
  1031 lists.
  1032 
  1033 * Pure/General/table.ML: the join operations now works via exceptions
  1034 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1035 admits slightly more efficient complex applications.
  1036 
  1037 * Pure: datatype Context.generic joins theory/Proof.context and
  1038 provides some facilities for code that works in either kind of
  1039 context, notably GenericDataFun for uniform theory and proof data.
  1040 
  1041 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1042 use Context.generic instead of just theory.
  1043 
  1044 * Pure: simplified internal attribute type, which is now always
  1045 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1046 vs. local (Proof.context) attributes have been discontinued, while
  1047 minimizing code duplication.  Thm.rule_attribute and
  1048 Thm.declaration_attribute build canonical attributes; see also
  1049 structure Context for further operations on Context.generic, notably
  1050 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1051 declarations and definitions.
  1052 
  1053 * Pure/kernel: consts certification ignores sort constraints given in
  1054 signature declarations.  (This information is not relevant to the
  1055 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1056 potential INCOMPATIBILITY.
  1057 
  1058 * Pure: axiomatic type classes are now purely definitional, with
  1059 explicit proofs of class axioms and super class relations performed
  1060 internally.  See Pure/axclass.ML for the main internal interfaces --
  1061 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1062 AxClass.axiomatize_class/classrel/arity supercede
  1063 Sign.add_classes/classrel/arities.
  1064 
  1065 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1066 global/local versions on theory vs. Proof.context have been
  1067 discontinued; Attrib.syntax and Method.syntax have been adapted
  1068 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1069 attributes, methods, etc.
  1070 
  1071 * Pure: several functions of signature "... -> theory -> theory * ..."
  1072 have been reoriented to "... -> theory -> ... * theory" in order to
  1073 allow natural usage in combination with the ||>, ||>>, |-> and
  1074 fold_map combinators.
  1075 
  1076 * Pure: official theorem names (closed derivations) and additional
  1077 comments (tags) are now strictly separate.  Name hints -- which are
  1078 maintained as tags -- may be attached any time without affecting the
  1079 derivation.
  1080 
  1081 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1082 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1083 achieve the old behaviour.
  1084 
  1085 * Pure: the "Goal" constant is now called "prop", supporting a
  1086 slightly more general idea of ``protecting'' meta-level rule
  1087 statements.
  1088 
  1089 * Pure: Logic.(un)varify only works in a global context, which is now
  1090 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1091 Logic.legacy_(un)varify as temporary workaround.
  1092 
  1093 * Pure: structure Name provides scalable operations for generating
  1094 internal variable names, notably Name.variants etc.  This replaces
  1095 some popular functions from term.ML:
  1096 
  1097   Term.variant		->  Name.variant
  1098   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1099   Term.invent_names	->  Name.invent_list
  1100 
  1101 Note that low-level renaming rarely occurs in new code -- operations
  1102 from structure Variable are used instead (see below).
  1103 
  1104 * Pure: structure Variable provides fundamental operations for proper
  1105 treatment of fixed/schematic variables in a context.  For example,
  1106 Variable.import introduces fixes for schematics of given facts and
  1107 Variable.export reverses the effect (up to renaming) -- this replaces
  1108 various freeze_thaw operations.
  1109 
  1110 * Pure: structure Goal provides simple interfaces for
  1111 init/conclude/finish and tactical prove operations (replacing former
  1112 Tactic.prove).  Goal.prove is the canonical way to prove results
  1113 within a given context; Goal.prove_global is a degraded version for
  1114 theory level goals, including a global Drule.standard.  Note that
  1115 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1116 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1117 in a locale context).
  1118 
  1119 * Isar: simplified treatment of user-level errors, using exception
  1120 ERROR of string uniformly.  Function error now merely raises ERROR,
  1121 without any side effect on output channels.  The Isar toplevel takes
  1122 care of proper display of ERROR exceptions.  ML code may use plain
  1123 handle/can/try; cat_error may be used to concatenate errors like this:
  1124 
  1125   ... handle ERROR msg => cat_error msg "..."
  1126 
  1127 Toplevel ML code (run directly or through the Isar toplevel) may be
  1128 embedded into the Isar toplevel with exception display/debug like
  1129 this:
  1130 
  1131   Isar.toplevel (fn () => ...)
  1132 
  1133 INCOMPATIBILITY, removed special transform_error facilities, removed
  1134 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1135 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1136 -- use plain ERROR instead.
  1137 
  1138 * Isar: theory setup now has type (theory -> theory), instead of a
  1139 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1140 
  1141 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1142 subject to ProofContext.debug/verbose flags.
  1143 
  1144 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1145 theory before entering a proof state.  Transactions now always see a
  1146 quasi-functional intermediate checkpoint, both in interactive and
  1147 batch mode.
  1148 
  1149 * Simplifier: the simpset of a running simplification process now
  1150 contains a proof context (cf. Simplifier.the_context), which is the
  1151 very context that the initial simpset has been retrieved from (by
  1152 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1153 (solver, looper etc.) may depend on arbitrary proof data.
  1154 
  1155 * Simplifier.inherit_context inherits the proof context (plus the
  1156 local bounds) of the current simplification process; any simproc
  1157 etc. that calls the Simplifier recursively should do this!  Removed
  1158 former Simplifier.inherit_bounds, which is already included here --
  1159 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1160 specify an explicit context using Simplifier.context/theory_context.
  1161 
  1162 * Simplifier/Classical Reasoner: more abstract interfaces
  1163 change_simpset/claset for modifying the simpset/claset reference of a
  1164 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1165 INCOMPATIBILITY.
  1166 
  1167 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1168 "Trueprop" etc.
  1169 
  1170 
  1171 *** System ***
  1172 
  1173 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1174 locations -- now includes the Isabelle version identifier as well.
  1175 This simplifies use of multiple Isabelle installations.
  1176 
  1177 * isabelle-process: option -S (secure mode) disables some critical
  1178 operations, notably runtime compilation and evaluation of ML source
  1179 code.
  1180 
  1181 
  1182 New in Isabelle2005 (October 2005)
  1183 ----------------------------------
  1184 
  1185 *** General ***
  1186 
  1187 * Theory headers: the new header syntax for Isar theories is
  1188 
  1189   theory <name>
  1190   imports <theory1> ... <theoryN>
  1191   uses <file1> ... <fileM>
  1192   begin
  1193 
  1194 where the 'uses' part is optional.  The previous syntax
  1195 
  1196   theory <name> = <theory1> + ... + <theoryN>:
  1197 
  1198 will disappear in the next release.  Use isatool fixheaders to convert
  1199 existing theory files.  Note that there is no change in ancient
  1200 non-Isar theories now, but these will disappear soon.
  1201 
  1202 * Theory loader: parent theories can now also be referred to via
  1203 relative and absolute paths.
  1204 
  1205 * Command 'find_theorems' searches for a list of criteria instead of a
  1206 list of constants. Known criteria are: intro, elim, dest, name:string,
  1207 simp:term, and any term. Criteria can be preceded by '-' to select
  1208 theorems that do not match. Intro, elim, dest select theorems that
  1209 match the current goal, name:s selects theorems whose fully qualified
  1210 name contain s, and simp:term selects all simplification rules whose
  1211 lhs match term.  Any other term is interpreted as pattern and selects
  1212 all theorems matching the pattern. Available in ProofGeneral under
  1213 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1214 
  1215   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1216 
  1217 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1218 matching the current goal as introduction rule and not having "HOL."
  1219 in their name (i.e. not being defined in theory HOL).
  1220 
  1221 * Command 'thms_containing' has been discontinued in favour of
  1222 'find_theorems'; INCOMPATIBILITY.
  1223 
  1224 * Communication with Proof General is now 8bit clean, which means that
  1225 Unicode text in UTF-8 encoding may be used within theory texts (both
  1226 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1227 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1228 
  1229   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1230   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1231 
  1232 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1233 Classical Reasoner.  Typical big applications run around 2 times
  1234 faster.
  1235 
  1236 
  1237 *** Document preparation ***
  1238 
  1239 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1240 of raw sources.  Only those symbols that do not require additional
  1241 LaTeX packages (depending on comments in isabellesym.sty) are
  1242 displayed properly, everything else is left verbatim.  isatool display
  1243 and isatool print are used as front ends (these are subject to the
  1244 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1245 
  1246 * Command tags control specific markup of certain regions of text,
  1247 notably folding and hiding.  Predefined tags include "theory" (for
  1248 theory begin and end), "proof" for proof commands, and "ML" for
  1249 commands involving ML code; the additional tags "visible" and
  1250 "invisible" are unused by default.  Users may give explicit tag
  1251 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1252 interpretation of tags is determined by the LaTeX job during document
  1253 preparation: see option -V of isatool usedir, or options -n and -t of
  1254 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1255 \isadroptag.
  1256 
  1257 Several document versions may be produced at the same time via isatool
  1258 usedir (the generated index.html will link all of them).  Typical
  1259 specifications include ''-V document=theory,proof,ML'' to present
  1260 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1261 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1262 these parts without any formal replacement text.  The Isabelle site
  1263 default settings produce ''document'' and ''outline'' versions as
  1264 specified above.
  1265 
  1266 * Several new antiquotations:
  1267 
  1268   @{term_type term} prints a term with its type annotated;
  1269 
  1270   @{typeof term} prints the type of a term;
  1271 
  1272   @{const const} is the same as @{term const}, but checks that the
  1273   argument is a known logical constant;
  1274 
  1275   @{term_style style term} and @{thm_style style thm} print a term or
  1276   theorem applying a "style" to it
  1277 
  1278   @{ML text}
  1279 
  1280 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1281 definitions, equations, inequations etc., 'concl' printing only the
  1282 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1283 to print the specified premise.  TermStyle.add_style provides an ML
  1284 interface for introducing further styles.  See also the "LaTeX Sugar"
  1285 document practical applications.  The ML antiquotation prints
  1286 type-checked ML expressions verbatim.
  1287 
  1288 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1289 and 'text' support optional locale specification '(in loc)', which
  1290 specifies the default context for interpreting antiquotations.  For
  1291 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1292 
  1293 * Option 'locale=NAME' of antiquotations specifies an alternative
  1294 context interpreting the subsequent argument.  For example: @{thm
  1295 [locale=lattice] inf_assoc}.
  1296 
  1297 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1298 a proof context.
  1299 
  1300 * Proper output of antiquotations for theory commands involving a
  1301 proof context (such as 'locale' or 'theorem (in loc) ...').
  1302 
  1303 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1304 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1305 
  1306 * isatool usedir: new option -C (default true) controls whether option
  1307 -D should include a copy of the original document directory; -C false
  1308 prevents unwanted effects such as copying of administrative CVS data.
  1309 
  1310 
  1311 *** Pure ***
  1312 
  1313 * Considerably improved version of 'constdefs' command.  Now performs
  1314 automatic type-inference of declared constants; additional support for
  1315 local structure declarations (cf. locales and HOL records), see also
  1316 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1317 sequential dependencies of definitions within a single 'constdefs'
  1318 section; moreover, the declared name needs to be an identifier.  If
  1319 all fails, consider to fall back on 'consts' and 'defs' separately.
  1320 
  1321 * Improved indexed syntax and implicit structures.  First of all,
  1322 indexed syntax provides a notational device for subscripted
  1323 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1324 expressions.  Secondly, in a local context with structure
  1325 declarations, number indexes \<^sub>n or the empty index (default
  1326 number 1) refer to a certain fixed variable implicitly; option
  1327 show_structs controls printing of implicit structures.  Typical
  1328 applications of these concepts involve record types and locales.
  1329 
  1330 * New command 'no_syntax' removes grammar declarations (and
  1331 translations) resulting from the given syntax specification, which is
  1332 interpreted in the same manner as for the 'syntax' command.
  1333 
  1334 * 'Advanced' translation functions (parse_translation etc.) may depend
  1335 on the signature of the theory context being presently used for
  1336 parsing/printing, see also isar-ref manual.
  1337 
  1338 * Improved 'oracle' command provides a type-safe interface to turn an
  1339 ML expression of type theory -> T -> term into a primitive rule of
  1340 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1341 is already included here); see also FOL/ex/IffExample.thy;
  1342 INCOMPATIBILITY.
  1343 
  1344 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1345 before); "cI" is no longer bound, use "c.intro" instead.
  1346 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1347 axclasses vs. locales.
  1348 
  1349 * Improved internal renaming of symbolic identifiers -- attach primes
  1350 instead of base 26 numbers.
  1351 
  1352 * New flag show_question_marks controls printing of leading question
  1353 marks in schematic variable names.
  1354 
  1355 * In schematic variable names, *any* symbol following \<^isub> or
  1356 \<^isup> is now treated as part of the base name.  For example, the
  1357 following works without printing of awkward ".0" indexes:
  1358 
  1359   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1360     by simp
  1361 
  1362 * Inner syntax includes (*(*nested*) comments*).
  1363 
  1364 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1365 annotations as "(00...)".
  1366 
  1367 * Clear separation of logical types and nonterminals, where the latter
  1368 may only occur in 'syntax' specifications or type abbreviations.
  1369 Before that distinction was only partially implemented via type class
  1370 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1371 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1372 exotic syntax specifications may require further adaption
  1373 (e.g. Cube/Cube.thy).
  1374 
  1375 * Removed obsolete type class "logic", use the top sort {} instead.
  1376 Note that non-logical types should be declared as 'nonterminals'
  1377 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1378 specifications.
  1379 
  1380 * Attributes 'induct' and 'cases': type or set names may now be
  1381 locally fixed variables as well.
  1382 
  1383 * Simplifier: can now control the depth to which conditional rewriting
  1384 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1385 Limit.
  1386 
  1387 * Simplifier: simplification procedures may now take the current
  1388 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1389 interface), which is very useful for calling the Simplifier
  1390 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1391 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1392 low-level mk_simproc no longer applies Logic.varify internally, to
  1393 allow for use in a context of fixed variables.
  1394 
  1395 * thin_tac now works even if the assumption being deleted contains !!
  1396 or ==>.  More generally, erule now works even if the major premise of
  1397 the elimination rule contains !! or ==>.
  1398 
  1399 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1400 
  1401 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1402 from Pure, which contains all common declarations already.  Both
  1403 theories are defined via plain Isabelle/Isar .thy files.
  1404 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1405 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1406 use isatool fixcpure to adapt your theory and ML sources.
  1407 
  1408 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1409 selections of theorems in named facts via index ranges.
  1410 
  1411 * 'print_theorems': in theory mode, really print the difference
  1412 wrt. the last state (works for interactive theory development only),
  1413 in proof mode print all local facts (cf. 'print_facts');
  1414 
  1415 * 'hide': option '(open)' hides only base names.
  1416 
  1417 * More efficient treatment of intermediate checkpoints in interactive
  1418 theory development.
  1419 
  1420 * Code generator is now invoked via code_module (incremental code
  1421 generation) and code_library (modular code generation, ML structures
  1422 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1423 must be quoted when used as identifiers.
  1424 
  1425 * New 'value' command for reading, evaluating and printing terms using
  1426 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1427 quoted when used as identifier.
  1428 
  1429 
  1430 *** Locales ***
  1431 
  1432 * New commands for the interpretation of locale expressions in
  1433 theories (1), locales (2) and proof contexts (3).  These generate
  1434 proof obligations from the expression specification.  After the
  1435 obligations have been discharged, theorems of the expression are added
  1436 to the theory, target locale or proof context.  The synopsis of the
  1437 commands is a follows:
  1438 
  1439   (1) interpretation expr inst
  1440   (2) interpretation target < expr
  1441   (3) interpret expr inst
  1442 
  1443 Interpretation in theories and proof contexts require a parameter
  1444 instantiation of terms from the current context.  This is applied to
  1445 specifications and theorems of the interpreted expression.
  1446 Interpretation in locales only permits parameter renaming through the
  1447 locale expression.  Interpretation is smart in that interpretations
  1448 that are active already do not occur in proof obligations, neither are
  1449 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1450 inspect active interpretations of a particular locale.  For details,
  1451 see the Isar Reference manual.  Examples can be found in
  1452 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1453 
  1454 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1455 'interpret' instead.
  1456 
  1457 * New context element 'constrains' for adding type constraints to
  1458 parameters.
  1459 
  1460 * Context expressions: renaming of parameters with syntax
  1461 redeclaration.
  1462 
  1463 * Locale declaration: 'includes' disallowed.
  1464 
  1465 * Proper static binding of attribute syntax -- i.e. types / terms /
  1466 facts mentioned as arguments are always those of the locale definition
  1467 context, independently of the context of later invocations.  Moreover,
  1468 locale operations (renaming and type / term instantiation) are applied
  1469 to attribute arguments as expected.
  1470 
  1471 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1472 actual attributes; rare situations may require Attrib.attribute to
  1473 embed those attributes into Attrib.src that lack concrete syntax.
  1474 Attribute implementations need to cooperate properly with the static
  1475 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1476 Attrib.XXX_thm etc. already do the right thing without further
  1477 intervention.  Only unusual applications -- such as "where" or "of"
  1478 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1479 on the context and the facts involved -- may have to assign parsed
  1480 values to argument tokens explicitly.
  1481 
  1482 * Changed parameter management in theorem generation for long goal
  1483 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1484 theorem statement in rare situations.
  1485 
  1486 * Locale inspection command 'print_locale' omits notes elements.  Use
  1487 'print_locale!' to have them included in the output.
  1488 
  1489 
  1490 *** Provers ***
  1491 
  1492 * Provers/hypsubst.ML: improved version of the subst method, for
  1493 single-step rewriting: it now works in bound variable contexts. New is
  1494 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1495 rewrite a different subterm than the original subst method, which is
  1496 still available as 'simplesubst'.
  1497 
  1498 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1499 and quasi orders.
  1500 
  1501 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1502 reflexive-transitive closure of relations.
  1503 
  1504 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1505 limit (previously hard-coded with a value of 20) user-definable.
  1506 
  1507 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1508 is peformed already.  Object-logics merely need to finish their
  1509 initial simpset configuration as before.  INCOMPATIBILITY.
  1510 
  1511 
  1512 *** HOL ***
  1513 
  1514 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1515 
  1516   syntax (epsilon)
  1517     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1518 
  1519 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1520 and x-symbol; use option '-m epsilon' to get it actually printed.
  1521 Moreover, the mathematically important symbolic identifier \<epsilon>
  1522 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1523 
  1524 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1525 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1526 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1527 support corresponding Isar calculations.
  1528 
  1529 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1530 instead of ":".
  1531 
  1532 * theory SetInterval: changed the syntax for open intervals:
  1533 
  1534   Old       New
  1535   {..n(}    {..<n}
  1536   {)n..}    {n<..}
  1537   {m..n(}   {m..<n}
  1538   {)m..n}   {m<..n}
  1539   {)m..n(}  {m<..<n}
  1540 
  1541 The old syntax is still supported but will disappear in the next
  1542 release.  For conversion use the following Emacs search and replace
  1543 patterns (these are not perfect but work quite well):
  1544 
  1545   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1546   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1547 
  1548 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1549 equalities in commutative rings; method 'algebra' provides a generic
  1550 interface.
  1551 
  1552 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1553 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1554 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1555 be a tuple pattern.
  1556 
  1557 Some new syntax forms are available:
  1558 
  1559   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1560   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1561   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1562   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1563 
  1564 The latter form "\<Sum>x < k. e" used to be based on a separate
  1565 function "Summation", which has been discontinued.
  1566 
  1567 * theory Finite_Set: in structured induction proofs, the insert case
  1568 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1569 (insert F x)'.
  1570 
  1571 * The 'refute' command has been extended to support a much larger
  1572 fragment of HOL, including axiomatic type classes, constdefs and
  1573 typedefs, inductive datatypes and recursion.
  1574 
  1575 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1576 Requires zChaff with proof generation to be installed.  See
  1577 HOL/ex/SAT_Examples.thy for examples.
  1578 
  1579 * Datatype induction via method 'induct' now preserves the name of the
  1580 induction variable. For example, when proving P(xs::'a list) by
  1581 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1582 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1583 in unstructured proof scripts.
  1584 
  1585 * Reworked implementation of records.  Improved scalability for
  1586 records with many fields, avoiding performance problems for type
  1587 inference. Records are no longer composed of nested field types, but
  1588 of nested extension types. Therefore the record type only grows linear
  1589 in the number of extensions and not in the number of fields.  The
  1590 top-level (users) view on records is preserved.  Potential
  1591 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1592 old record representation. The type generated for a record is called
  1593 <record_name>_ext_type.
  1594 
  1595 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1596 proofs triggered by a record definition or a simproc (if
  1597 quick_and_dirty is enabled).  Definitions of large records can take
  1598 quite long.
  1599 
  1600 New simproc record_upd_simproc for simplification of multiple record
  1601 updates enabled by default.  Moreover, trivial updates are also
  1602 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1603 occasionally, since simplification is more powerful by default.
  1604 
  1605 * typedef: proper support for polymorphic sets, which contain extra
  1606 type-variables in the term.
  1607 
  1608 * Simplifier: automatically reasons about transitivity chains
  1609 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1610 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1611 old proofs break occasionally as simplification may now solve more
  1612 goals than previously.
  1613 
  1614 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1615 present.  Works for all partial orders (class "order"), in particular
  1616 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1617 just like y <= x.
  1618 
  1619 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1620 bound variable or a constant then the let is unfolded.  Otherwise
  1621 first a is simplified to b, and then f b is simplified to g. If
  1622 possible we abstract b from g arriving at "let x = b in h x",
  1623 otherwise we unfold the let and arrive at g.  The simproc can be
  1624 enabled/disabled by the reference use_let_simproc.  Potential
  1625 INCOMPATIBILITY since simplification is more powerful by default.
  1626 
  1627 * Classical reasoning: the meson method now accepts theorems as arguments.
  1628 
  1629 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1630 jobs to provide advice on the provability of subgoals.
  1631 
  1632 * Theory OrderedGroup and Ring_and_Field: various additions and
  1633 improvements to faciliate calculations involving equalities and
  1634 inequalities.
  1635 
  1636 The following theorems have been eliminated or modified
  1637 (INCOMPATIBILITY):
  1638 
  1639   abs_eq             now named abs_of_nonneg
  1640   abs_of_ge_0        now named abs_of_nonneg
  1641   abs_minus_eq       now named abs_of_nonpos
  1642   imp_abs_id         now named abs_of_nonneg
  1643   imp_abs_neg_id     now named abs_of_nonpos
  1644   mult_pos           now named mult_pos_pos
  1645   mult_pos_le        now named mult_nonneg_nonneg
  1646   mult_pos_neg_le    now named mult_nonneg_nonpos
  1647   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1648   mult_neg           now named mult_neg_neg
  1649   mult_neg_le        now named mult_nonpos_nonpos
  1650 
  1651 * Theory Parity: added rules for simplifying exponents.
  1652 
  1653 * Theory List:
  1654 
  1655 The following theorems have been eliminated or modified
  1656 (INCOMPATIBILITY):
  1657 
  1658   list_all_Nil       now named list_all.simps(1)
  1659   list_all_Cons      now named list_all.simps(2)
  1660   list_all_conv      now named list_all_iff
  1661   set_mem_eq         now named mem_iff
  1662 
  1663 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1664 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1665 
  1666 
  1667 *** HOL-Complex ***
  1668 
  1669 * Theory RealDef: better support for embedding natural numbers and
  1670 integers in the reals.
  1671 
  1672 The following theorems have been eliminated or modified
  1673 (INCOMPATIBILITY):
  1674 
  1675   exp_ge_add_one_self  now requires no hypotheses
  1676   real_of_int_add      reversed direction of equality (use [symmetric])
  1677   real_of_int_minus    reversed direction of equality (use [symmetric])
  1678   real_of_int_diff     reversed direction of equality (use [symmetric])
  1679   real_of_int_mult     reversed direction of equality (use [symmetric])
  1680 
  1681 * Theory RComplete: expanded support for floor and ceiling functions.
  1682 
  1683 * Theory Ln is new, with properties of the natural logarithm
  1684 
  1685 * Hyperreal: There is a new type constructor "star" for making
  1686 nonstandard types.  The old type names are now type synonyms:
  1687 
  1688   hypreal = real star
  1689   hypnat = nat star
  1690   hcomplex = complex star
  1691 
  1692 * Hyperreal: Many groups of similarly-defined constants have been
  1693 replaced by polymorphic versions (INCOMPATIBILITY):
  1694 
  1695   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1696 
  1697   starset      <-- starsetNat, starsetC
  1698   *s*          <-- *sNat*, *sc*
  1699   starset_n    <-- starsetNat_n, starsetC_n
  1700   *sn*         <-- *sNatn*, *scn*
  1701   InternalSets <-- InternalNatSets, InternalCSets
  1702 
  1703   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1704   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1705   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1706   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1707   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1708 
  1709 * Hyperreal: Many type-specific theorems have been removed in favor of
  1710 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1711 
  1712   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1713   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1714   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1715   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1716   right_minus <-- hypreal_add_minus
  1717   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1718   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1719   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1720   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1721   mult_1_right <-- hcomplex_mult_one_right
  1722   mult_zero_left <-- hcomplex_mult_zero_left
  1723   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1724   right_distrib <-- hypnat_add_mult_distrib2
  1725   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1726   right_inverse <-- hypreal_mult_inverse
  1727   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1728   order_refl <-- {hypreal,hypnat}_le_refl
  1729   order_trans <-- {hypreal,hypnat}_le_trans
  1730   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1731   order_less_le <-- {hypreal,hypnat}_less_le
  1732   linorder_linear <-- {hypreal,hypnat}_le_linear
  1733   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1734   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1735   add_nonneg_nonneg <-- hypreal_le_add_order
  1736 
  1737 * Hyperreal: Separate theorems having to do with type-specific
  1738 versions of constants have been merged into theorems that apply to the
  1739 new polymorphic constants (INCOMPATIBILITY):
  1740 
  1741   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1742   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1743   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1744   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1745   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1746   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1747   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1748   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1749   STAR_diff <-- {STAR,STARC}_diff
  1750   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1751     STARC_hcomplex_of_complex}_image_subset
  1752   starset_n_Un <-- starset{Nat,C}_n_Un
  1753   starset_n_Int <-- starset{Nat,C}_n_Int
  1754   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1755   starset_n_diff <-- starset{Nat,C}_n_diff
  1756   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1757   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1758   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1759   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1760   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1761   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1762   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1763   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1764   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1765   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1766   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1767   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1768   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1769   starfun_diff <-- starfun{C,RC,CR}_diff
  1770   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1771   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1772   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1773   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1774   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1775   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1776   starfun_Id <-- starfunC_Id
  1777   starfun_approx <-- starfun{Nat,CR}_approx
  1778   starfun_capprox <-- starfun{C,RC}_capprox
  1779   starfun_abs <-- starfunNat_rabs
  1780   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1781   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1782   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1783   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1784   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1785   starfun_add_approx <-- starfunCR_add_approx
  1786   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1787   starfun_divide <-- starfun{C,CR,RC}_divide
  1788   starfun_n <-- starfun{Nat,C}_n
  1789   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1790   starfun_n_add <-- starfun{Nat,C}_n_add
  1791   starfun_n_add_minus <-- starfunNat_n_add_minus
  1792   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1793   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1794   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1795 
  1796   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1797   star_n_minus <-- {hypreal,hcomplex}_minus
  1798   star_n_diff <-- {hypreal,hcomplex}_diff
  1799   star_n_mult <-- {hypreal,hcomplex}_mult
  1800   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1801   star_n_le <-- {hypreal,hypnat}_le
  1802   star_n_less <-- {hypreal,hypnat}_less
  1803   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1804   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1805   star_n_abs <-- hypreal_hrabs
  1806   star_n_divide <-- hcomplex_divide
  1807 
  1808   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1809   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1810   star_of_diff <-- hypreal_of_real_diff
  1811   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1812   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1813   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1814   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1815   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1816   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1817   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1818   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1819   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1820   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1821   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1822   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1823   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1824   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1825   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1826   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1827   star_of_power <-- hypreal_of_real_power
  1828   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1829 
  1830 * Hyperreal: new method "transfer" that implements the transfer
  1831 principle of nonstandard analysis. With a subgoal that mentions
  1832 nonstandard types like "'a star", the command "apply transfer"
  1833 replaces it with an equivalent one that mentions only standard types.
  1834 To be successful, all free variables must have standard types; non-
  1835 standard variables must have explicit universal quantifiers.
  1836 
  1837 * Hyperreal: A theory of Taylor series.
  1838 
  1839 
  1840 *** HOLCF ***
  1841 
  1842 * Discontinued special version of 'constdefs' (which used to support
  1843 continuous functions) in favor of the general Pure one with full
  1844 type-inference.
  1845 
  1846 * New simplification procedure for solving continuity conditions; it
  1847 is much faster on terms with many nested lambda abstractions (cubic
  1848 instead of exponential time).
  1849 
  1850 * New syntax for domain package: selector names are now optional.
  1851 Parentheses should be omitted unless argument is lazy, for example:
  1852 
  1853   domain 'a stream = cons "'a" (lazy "'a stream")
  1854 
  1855 * New command 'fixrec' for defining recursive functions with pattern
  1856 matching; defining multiple functions with mutual recursion is also
  1857 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1858 sinr, or any data constructor defined by the domain package. The given
  1859 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1860 syntax and examples.
  1861 
  1862 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1863 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1864 but the proof obligation additionally includes an admissibility
  1865 requirement. The packages generate instances of class cpo or pcpo,
  1866 with continuity and strictness theorems for Rep and Abs.
  1867 
  1868 * HOLCF: Many theorems have been renamed according to a more standard naming
  1869 scheme (INCOMPATIBILITY):
  1870 
  1871   foo_inject:  "foo$x = foo$y ==> x = y"
  1872   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1873   foo_less:    "(foo$x << foo$y) = (x << y)"
  1874   foo_strict:  "foo$UU = UU"
  1875   foo_defined: "... ==> foo$x ~= UU"
  1876   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1877 
  1878 
  1879 *** ZF ***
  1880 
  1881 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1882 including the First Isomorphism Theorem (on quotienting by the kernel
  1883 of a homomorphism).
  1884 
  1885 * ZF/Simplifier: install second copy of type solver that actually
  1886 makes use of TC rules declared to Isar proof contexts (or locales);
  1887 the old version is still required for ML proof scripts.
  1888 
  1889 
  1890 *** Cube ***
  1891 
  1892 * Converted to Isar theory format; use locales instead of axiomatic
  1893 theories.
  1894 
  1895 
  1896 *** ML ***
  1897 
  1898 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1899 for ||>, ||>>, |>>,
  1900 
  1901 * Pure/library.ML no longer defines its own option datatype, but uses
  1902 that of the SML basis, which has constructors NONE and SOME instead of
  1903 None and Some, as well as exception Option.Option instead of OPTION.
  1904 The functions the, if_none, is_some, is_none have been adapted
  1905 accordingly, while Option.map replaces apsome.
  1906 
  1907 * Pure/library.ML: the exception LIST has been given up in favour of
  1908 the standard exceptions Empty and Subscript, as well as
  1909 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1910 superceded by the standard hd and tl functions etc.
  1911 
  1912 A number of basic list functions are no longer exported to the ML
  1913 toplevel, as they are variants of predefined functions.  The following
  1914 suggests how one can translate existing code:
  1915 
  1916     rev_append xs ys = List.revAppend (xs, ys)
  1917     nth_elem (i, xs) = List.nth (xs, i)
  1918     last_elem xs = List.last xs
  1919     flat xss = List.concat xss
  1920     seq fs = List.app fs
  1921     partition P xs = List.partition P xs
  1922     mapfilter f xs = List.mapPartial f xs
  1923 
  1924 * Pure/library.ML: several combinators for linear functional
  1925 transformations, notably reverse application and composition:
  1926 
  1927   x |> f                f #> g
  1928   (x, y) |-> f          f #-> g
  1929 
  1930 * Pure/library.ML: introduced/changed precedence of infix operators:
  1931 
  1932   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1933   infix 2 ?;
  1934   infix 3 o oo ooo oooo;
  1935   infix 4 ~~ upto downto;
  1936 
  1937 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1938 infix operators.
  1939 
  1940 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1941 fold_map support linear functional transformations and nesting.  For
  1942 example:
  1943 
  1944   fold f [x1, ..., xN] y =
  1945     y |> f x1 |> ... |> f xN
  1946 
  1947   (fold o fold) f [xs1, ..., xsN] y =
  1948     y |> fold f xs1 |> ... |> fold f xsN
  1949 
  1950   fold f [x1, ..., xN] =
  1951     f x1 #> ... #> f xN
  1952 
  1953   (fold o fold) f [xs1, ..., xsN] =
  1954     fold f xs1 #> ... #> fold f xsN
  1955 
  1956 * Pure/library.ML: the following selectors on type 'a option are
  1957 available:
  1958 
  1959   the:               'a option -> 'a  (*partial*)
  1960   these:             'a option -> 'a  where 'a = 'b list
  1961   the_default: 'a -> 'a option -> 'a
  1962   the_list:          'a option -> 'a list
  1963 
  1964 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1965 basic operations for association lists, following natural argument
  1966 order; moreover the explicit equality predicate passed here avoids
  1967 potentially expensive polymorphic runtime equality checks.
  1968 The old functions may be expressed as follows:
  1969 
  1970   assoc = uncurry (AList.lookup (op =))
  1971   assocs = these oo AList.lookup (op =)
  1972   overwrite = uncurry (AList.update (op =)) o swap
  1973 
  1974 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1975 
  1976   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1977   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1978 
  1979 replacing make_keylist and keyfilter (occassionally used)
  1980 Naive rewrites:
  1981 
  1982   make_keylist = AList.make
  1983   keyfilter = AList.find (op =)
  1984 
  1985 * eq_fst and eq_snd now take explicit equality parameter, thus
  1986   avoiding eqtypes. Naive rewrites:
  1987 
  1988     eq_fst = eq_fst (op =)
  1989     eq_snd = eq_snd (op =)
  1990 
  1991 * Removed deprecated apl and apr (rarely used).
  1992   Naive rewrites:
  1993 
  1994     apl (n, op) =>>= curry op n
  1995     apr (op, m) =>>= fn n => op (n, m)
  1996 
  1997 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1998 provides a reasonably efficient light-weight implementation of sets as
  1999 lists.
  2000 
  2001 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2002 few new operations; existing lookup and update are now curried to
  2003 follow natural argument order (for use with fold etc.);
  2004 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2005 
  2006 * Pure/General: output via the Isabelle channels of
  2007 writeln/warning/error etc. is now passed through Output.output, with a
  2008 hook for arbitrary transformations depending on the print_mode
  2009 (cf. Output.add_mode -- the first active mode that provides a output
  2010 function wins).  Already formatted output may be embedded into further
  2011 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2012 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2013 accommodate easy composition of diagnostic messages etc.  Programmers
  2014 rarely need to care about Output.output or Output.raw at all, with
  2015 some notable exceptions: Output.output is required when bypassing the
  2016 standard channels (writeln etc.), or in token translations to produce
  2017 properly formatted results; Output.raw is required when capturing
  2018 already output material that will eventually be presented to the user
  2019 a second time.  For the default print mode, both Output.output and
  2020 Output.raw have no effect.
  2021 
  2022 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2023 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2024 cumulative results are displayed at the end of a batch session.
  2025 
  2026 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2027 replaced by File.platform_path and File.shell_path (with appropriate
  2028 hooks).  This provides a clean interface for unusual systems where the
  2029 internal and external process view of file names are different.
  2030 
  2031 * Pure: more efficient orders for basic syntactic entities: added
  2032 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2033 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2034 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2035 orders now -- potential INCOMPATIBILITY for code that depends on a
  2036 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2037 Library.sort_strings on result).
  2038 
  2039 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2040 fold_types traverse types/terms from left to right, observing natural
  2041 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2042 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2043 
  2044 * Pure: name spaces have been refined, with significant changes of the
  2045 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2046 to extern(_table).  The plain name entry path is superceded by a
  2047 general 'naming' context, which also includes the 'policy' to produce
  2048 a fully qualified name and external accesses of a fully qualified
  2049 name; NameSpace.extend is superceded by context dependent
  2050 Sign.declare_name.  Several theory and proof context operations modify
  2051 the naming context.  Especially note Theory.restore_naming and
  2052 ProofContext.restore_naming to get back to a sane state; note that
  2053 Theory.add_path is no longer sufficient to recover from
  2054 Theory.absolute_path in particular.
  2055 
  2056 * Pure: new flags short_names (default false) and unique_names
  2057 (default true) for controlling output of qualified names.  If
  2058 short_names is set, names are printed unqualified.  If unique_names is
  2059 reset, the name prefix is reduced to the minimum required to achieve
  2060 the original result when interning again, even if there is an overlap
  2061 with earlier declarations.
  2062 
  2063 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2064 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2065 (useful for printing error messages).  INCOMPATIBILITY.
  2066 
  2067 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2068 Theory.theory are now identified, referring to the universal
  2069 Context.theory (see Pure/context.ML).  Actual signature and theory
  2070 content is managed as theory data.  The old code and interfaces were
  2071 spread over many files and structures; the new arrangement introduces
  2072 considerable INCOMPATIBILITY to gain more clarity:
  2073 
  2074   Context -- theory management operations (name, identity, inclusion,
  2075     parents, ancestors, merge, etc.), plus generic theory data;
  2076 
  2077   Sign -- logical signature and syntax operations (declaring consts,
  2078     types, etc.), plus certify/read for common entities;
  2079 
  2080   Theory -- logical theory operations (stating axioms, definitions,
  2081     oracles), plus a copy of logical signature operations (consts,
  2082     types, etc.); also a few basic management operations (Theory.copy,
  2083     Theory.merge, etc.)
  2084 
  2085 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2086 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2087 for convenience -- they merely return the theory.
  2088 
  2089 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2090 
  2091 * Pure: the Isar proof context type is already defined early in Pure
  2092 as Context.proof (note that ProofContext.context and Proof.context are
  2093 aliases, where the latter is the preferred name).  This enables other
  2094 Isabelle components to refer to that type even before Isar is present.
  2095 
  2096 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2097 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2098 any of these kinds.  For example, Sign.intern typeK is now
  2099 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2100 Theory.hide_types.  Also note that former
  2101 Theory.hide_classes/types/consts are now
  2102 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2103 internalize their arguments!  INCOMPATIBILITY.
  2104 
  2105 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2106 datatype thmref (with constructors Name and NameSelection) instead of
  2107 plain string -- INCOMPATIBILITY;
  2108 
  2109 * Pure: cases produced by proof methods specify options, where NONE
  2110 means to remove case bindings -- INCOMPATIBILITY in
  2111 (RAW_)METHOD_CASES.
  2112 
  2113 * Pure: the following operations retrieve axioms or theorems from a
  2114 theory node or theory hierarchy, respectively:
  2115 
  2116   Theory.axioms_of: theory -> (string * term) list
  2117   Theory.all_axioms_of: theory -> (string * term) list
  2118   PureThy.thms_of: theory -> (string * thm) list
  2119   PureThy.all_thms_of: theory -> (string * thm) list
  2120 
  2121 * Pure: print_tac now outputs the goal through the trace channel.
  2122 
  2123 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2124 Reference Toplevel.debug (default false) controls detailed printing
  2125 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2126 controls execution profiling -- set to 1 for time and 2 for space
  2127 (both increase the runtime).
  2128 
  2129 * Isar session: The initial use of ROOT.ML is now always timed,
  2130 i.e. the log will show the actual process times, in contrast to the
  2131 elapsed wall-clock time that the outer shell wrapper produces.
  2132 
  2133 * Simplifier: improved handling of bound variables (nameless
  2134 representation, avoid allocating new strings).  Simprocs that invoke
  2135 the Simplifier recursively should use Simplifier.inherit_bounds to
  2136 avoid local name clashes.  Failure to do so produces warnings
  2137 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2138 for further details.
  2139 
  2140 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2141 bindings for all theorems stored within a given theory; this may help
  2142 in porting non-Isar theories to Isar ones, while keeping ML proof
  2143 scripts for the time being.
  2144 
  2145 * ML operator HTML.with_charset specifies the charset begin used for
  2146 generated HTML files.  For example:
  2147 
  2148   HTML.with_charset "utf-8" use_thy "Hebrew";
  2149   HTML.with_charset "utf-8" use_thy "Chinese";
  2150 
  2151 
  2152 *** System ***
  2153 
  2154 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2155 isabelle, isatool etc.).
  2156 
  2157 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2158 isatool doc, isatool mkdir, display_drafts etc.).
  2159 
  2160 * isatool usedir: option -f allows specification of the ML file to be
  2161 used by Isabelle; default is ROOT.ML.
  2162 
  2163 * New isatool version outputs the version identifier of the Isabelle
  2164 distribution being used.
  2165 
  2166 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2167 (containing Boolean satisfiability problems) into Isabelle/HOL
  2168 theories.
  2169 
  2170 
  2171 
  2172 New in Isabelle2004 (April 2004)
  2173 --------------------------------
  2174 
  2175 *** General ***
  2176 
  2177 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2178   Replaces linorder.ML.
  2179 
  2180 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2181   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2182   (\<a>...\<z>), are now considered normal letters, and can therefore
  2183   be used anywhere where an ASCII letter (a...zA...Z) has until
  2184   now. COMPATIBILITY: This obviously changes the parsing of some
  2185   terms, especially where a symbol has been used as a binder, say
  2186   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2187   as an identifier.  Fix it by inserting a space around former
  2188   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2189   existing theory and ML files.
  2190 
  2191 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2192 
  2193 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2194   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2195   a normal (but invisible) letter. For multiple letter subscripts repeat
  2196   \<^isub> like this: x\<^isub>1\<^isub>2.
  2197 
  2198 * Pure: There are now sub-/superscripts that can span more than one
  2199   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2200   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2201   superscript. The new control characters are not identifier parts.
  2202 
  2203 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2204   content of "..." to the latex file instead of \isacntrl... . The "..."
  2205   may consist of any printable characters excluding the end bracket >.
  2206 
  2207 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2208   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2209   declare constants "final", which prevents their being given a definition
  2210   later.  It is useful for constants whose behaviour is fixed axiomatically
  2211   rather than definitionally, such as the meta-logic connectives.
  2212 
  2213 * Pure: 'instance' now handles general arities with general sorts
  2214   (i.e. intersections of classes),
  2215 
  2216 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2217   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2218   It can be changed to alter the colors/layout of generated pages.
  2219 
  2220 
  2221 *** Isar ***
  2222 
  2223 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2224   cut_tac, subgoal_tac and thin_tac:
  2225   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2226     locales are no longer forced to write Isar proof scripts.
  2227     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2228     emulations.
  2229   - INCOMPATIBILITY: names of variables to be instantiated may no
  2230     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2231     This is consistent with the instantiation attribute "where".
  2232 
  2233 * Attributes "where" and "of":
  2234   - Now take type variables of instantiated theorem into account when reading
  2235     the instantiation string.  This fixes a bug that caused instantiated
  2236     theorems to have too special types in some circumstances.
  2237   - "where" permits explicit instantiations of type variables.
  2238 
  2239 * Calculation commands "moreover" and "also" no longer interfere with
  2240   current facts ("this"), admitting arbitrary combinations with "then"
  2241   and derived forms.
  2242 
  2243 * Locales:
  2244   - Goal statements involving the context element "includes" no longer
  2245     generate theorems with internal delta predicates (those ending on
  2246     "_axioms") in the premise.
  2247     Resolve particular premise with <locale>.intro to obtain old form.
  2248   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2249     specification and "includes" elements in goal statement.
  2250   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2251     [intro?] and [elim?] (respectively) by default.
  2252   - Experimental command for instantiation of locales in proof contexts:
  2253         instantiate <label>[<attrs>]: <loc>
  2254     Instantiates locale <loc> and adds all its theorems to the current context
  2255     taking into account their attributes.  Label and attrs are optional
  2256     modifiers, like in theorem declarations.  If present, names of
  2257     instantiated theorems are qualified with <label>, and the attributes
  2258     <attrs> are applied after any attributes these theorems might have already.
  2259       If the locale has assumptions, a chained fact of the form
  2260     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2261     are derived.  The command does not support old-style locales declared
  2262     with "locale (open)".
  2263       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2264 
  2265 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2266   (Isar) contexts.
  2267 
  2268 
  2269 *** HOL ***
  2270 
  2271 * Proof import: new image HOL4 contains the imported library from
  2272   the HOL4 system with about 2500 theorems. It is imported by
  2273   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2274   can be used like any other Isabelle image.  See
  2275   HOL/Import/HOL/README for more information.
  2276 
  2277 * Simplifier:
  2278   - Much improved handling of linear and partial orders.
  2279     Reasoners for linear and partial orders are set up for type classes
  2280     "linorder" and "order" respectively, and are added to the default simpset
  2281     as solvers.  This means that the simplifier can build transitivity chains
  2282     to solve goals from the assumptions.
  2283   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2284     of blast or auto after simplification become unnecessary because the goal
  2285     is solved by simplification already.
  2286 
  2287 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2288     all proved in axiomatic type classes for semirings, rings and fields.
  2289 
  2290 * Numerics:
  2291   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2292     now formalized using the Ring_and_Field theory mentioned above.
  2293   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2294     than before, because now they are set up once in a generic manner.
  2295   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2296     Look for the general versions in Ring_and_Field (and Power if they concern
  2297     exponentiation).
  2298 
  2299 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2300 
  2301 * Records:
  2302   - Record types are now by default printed with their type abbreviation
  2303     instead of the list of all field types. This can be configured via
  2304     the reference "print_record_type_abbr".
  2305   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2306     (not enabled by default).
  2307   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2308     EX x. x = sel r to True (not enabled by default).
  2309   - Tactic "record_split_simp_tac" to split and simplify records added.
  2310 
  2311 * 'specification' command added, allowing for definition by
  2312   specification.  There is also an 'ax_specification' command that
  2313   introduces the new constants axiomatically.
  2314 
  2315 * arith(_tac) is now able to generate counterexamples for reals as well.
  2316 
  2317 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2318 
  2319 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2320   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2321 
  2322 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2323   matrix theory to linear programming.
  2324 
  2325 * Unions and Intersections:
  2326   The latex output syntax of UN and INT has been changed
  2327   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2328   i.e. the index formulae has become a subscript.
  2329   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2330 
  2331 * Unions and Intersections over Intervals:
  2332   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2333   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2334   like in normal math, and corresponding versions for < and for intersection.
  2335 
  2336 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2337   lexicographic dictonary ordering has been added as "lexord".
  2338 
  2339 * ML: the legacy theory structures Int and List have been removed. They had
  2340   conflicted with ML Basis Library structures having the same names.
  2341 
  2342 * 'refute' command added to search for (finite) countermodels.  Only works
  2343   for a fragment of HOL.  The installation of an external SAT solver is
  2344   highly recommended.  See "HOL/Refute.thy" for details.
  2345 
  2346 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2347   formulae under an assignment of free variables to random values.
  2348   In contrast to 'refute', it can deal with inductive datatypes,
  2349   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2350   for examples.
  2351 
  2352 
  2353 *** HOLCF ***
  2354 
  2355 * Streams now come with concatenation and are part of the HOLCF image
  2356 
  2357 
  2358 
  2359 New in Isabelle2003 (May 2003)
  2360 ------------------------------
  2361 
  2362 *** General ***
  2363 
  2364 * Provers/simplifier:
  2365 
  2366   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2367     Assumptions are now subject to complete mutual simplification,
  2368     not just from left to right. The simplifier now preserves
  2369     the order of assumptions.
  2370 
  2371     Potential INCOMPATIBILITY:
  2372 
  2373     -- simp sometimes diverges where the old version did
  2374        not, e.g. invoking simp on the goal
  2375 
  2376         [| P (f x); y = x; f x = f y |] ==> Q
  2377 
  2378        now gives rise to the infinite reduction sequence
  2379 
  2380         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2381 
  2382        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2383        kind of problem.
  2384 
  2385     -- Tactics combining classical reasoner and simplification (such as auto)
  2386        are also affected by this change, because many of them rely on
  2387        simp. They may sometimes diverge as well or yield a different numbers
  2388        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2389        in case of problems. Sometimes subsequent calls to the classical
  2390        reasoner will fail because a preceeding call to the simplifier too
  2391        eagerly simplified the goal, e.g. deleted redundant premises.
  2392 
  2393   - The simplifier trace now shows the names of the applied rewrite rules
  2394 
  2395   - You can limit the number of recursive invocations of the simplifier
  2396     during conditional rewriting (where the simplifie tries to solve the
  2397     conditions before applying the rewrite rule):
  2398     ML "simp_depth_limit := n"
  2399     where n is an integer. Thus you can force termination where previously
  2400     the simplifier would diverge.
  2401 
  2402   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2403 
  2404   - No longer aborts on failed congruence proof.  Instead, the
  2405     congruence is ignored.
  2406 
  2407 * Pure: New generic framework for extracting programs from constructive
  2408   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2409   as HOL/Extraction for some case studies.
  2410 
  2411 * Pure: The main goal of the proof state is no longer shown by default, only
  2412 the subgoals. This behaviour is controlled by a new flag.
  2413    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2414 (ML: Proof.show_main_goal).
  2415 
  2416 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2417 rules whose conclusion matches subgoal 1:
  2418       PG menu: Isabelle/Isar -> Show me -> matching rules
  2419 The rules are ordered by how closely they match the subgoal.
  2420 In particular, rules that solve a subgoal outright are displayed first
  2421 (or rather last, the way they are printed).
  2422 (ML: ProofGeneral.print_intros())
  2423 
  2424 * Pure: New flag trace_unify_fail causes unification to print
  2425 diagnostic information (PG: in trace buffer) when it fails. This is
  2426 useful for figuring out why single step proofs like rule, erule or
  2427 assumption failed.
  2428 
  2429 * Pure: Locale specifications now produce predicate definitions
  2430 according to the body of text (covering assumptions modulo local
  2431 definitions); predicate "loc_axioms" covers newly introduced text,
  2432 while "loc" is cumulative wrt. all included locale expressions; the
  2433 latter view is presented only on export into the global theory
  2434 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2435 on the old view without predicates;
  2436 
  2437 * Pure: predefined locales "var" and "struct" are useful for sharing
  2438 parameters (as in CASL, for example); just specify something like
  2439 ``var x + var y + struct M'' as import;
  2440 
  2441 * Pure: improved thms_containing: proper indexing of facts instead of
  2442 raw theorems; check validity of results wrt. current name space;
  2443 include local facts of proof configuration (also covers active
  2444 locales), cover fixed variables in index; may use "_" in term
  2445 specification; an optional limit for the number of printed facts may
  2446 be given (the default is 40);
  2447 
  2448 * Pure: disallow duplicate fact bindings within new-style theory files
  2449 (batch-mode only);
  2450 
  2451 * Provers: improved induct method: assumptions introduced by case
  2452 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2453 the goal statement); "foo" still refers to all facts collectively;
  2454 
  2455 * Provers: the function blast.overloaded has been removed: all constants
  2456 are regarded as potentially overloaded, which improves robustness in exchange
  2457 for slight decrease in efficiency;
  2458 
  2459 * Provers/linorder: New generic prover for transitivity reasoning over
  2460 linear orders.  Note: this prover is not efficient!
  2461 
  2462 * Isar: preview of problems to finish 'show' now produce an error
  2463 rather than just a warning (in interactive mode);
  2464 
  2465 
  2466 *** HOL ***
  2467 
  2468 * arith(_tac)
  2469 
  2470  - Produces a counter example if it cannot prove a goal.
  2471    Note that the counter example may be spurious if the goal is not a formula
  2472    of quantifier-free linear arithmetic.
  2473    In ProofGeneral the counter example appears in the trace buffer.
  2474 
  2475  - Knows about div k and mod k where k is a numeral of type nat or int.
  2476 
  2477  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2478    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2479    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2480 
  2481 * simp's arithmetic capabilities have been enhanced a bit: it now
  2482 takes ~= in premises into account (by performing a case split);
  2483 
  2484 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2485 are distributed over a sum of terms;
  2486 
  2487 * New tactic "trans_tac" and method "trans" instantiate
  2488 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2489 "<=", "<" and "=").
  2490 
  2491 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2492 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2493 
  2494 * 'typedef' command has new option "open" to suppress the set
  2495 definition;
  2496 
  2497 * functions Min and Max on finite sets have been introduced (theory
  2498 Finite_Set);
  2499 
  2500 * attribute [symmetric] now works for relations as well; it turns
  2501 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2502 
  2503 * induct over a !!-quantified statement (say !!x1..xn):
  2504   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2505 
  2506 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2507 %x. None. Warning: empty_def now refers to the previously hidden definition
  2508 of the empty set.
  2509 
  2510 * Algebra: formalization of classical algebra.  Intended as base for
  2511 any algebraic development in Isabelle.  Currently covers group theory
  2512 (up to Sylow's theorem) and ring theory (Universal Property of
  2513 Univariate Polynomials).  Contributions welcome;
  2514 
  2515 * GroupTheory: deleted, since its material has been moved to Algebra;
  2516 
  2517 * Complex: new directory of the complex numbers with numeric constants,
  2518 nonstandard complex numbers, and some complex analysis, standard and
  2519 nonstandard (Jacques Fleuriot);
  2520 
  2521 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2522 
  2523 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2524 Fleuriot);
  2525 
  2526 * Real/HahnBanach: updated and adapted to locales;
  2527 
  2528 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2529 Gray and Kramer);
  2530 
  2531 * UNITY: added the Meier-Sanders theory of progress sets;
  2532 
  2533 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2534 as abstract algorithms, instantiated to the JVM;
  2535 
  2536 * Bali: Java source language formalization. Type system, operational
  2537 semantics, axiomatic semantics. Supported language features:
  2538 classes, interfaces, objects,virtual methods, static methods,
  2539 static/instance fields, arrays, access modifiers, definite
  2540 assignment, exceptions.
  2541 
  2542 
  2543 *** ZF ***
  2544 
  2545 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2546 universe, etc.);
  2547 
  2548 * Main ZF: virtually all theories converted to new-style format;
  2549 
  2550 
  2551 *** ML ***
  2552 
  2553 * Pure: Tactic.prove provides sane interface for internal proofs;
  2554 omits the infamous "standard" operation, so this is more appropriate
  2555 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2556 
  2557 * Pure: improved error reporting of simprocs;
  2558 
  2559 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2560 up simprocs;
  2561 
  2562 
  2563 *** Document preparation ***
  2564 
  2565 * uses \par instead of \\ for line breaks in theory text. This may
  2566 shift some page breaks in large documents. To get the old behaviour
  2567 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2568 
  2569 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2570 other packages
  2571 
  2572 * \<euro> now needs package babel/greek instead of marvosym (which
  2573 broke \Rightarrow)
  2574 
  2575 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2576 textcomp package)
  2577 
  2578 
  2579 
  2580 New in Isabelle2002 (March 2002)
  2581 --------------------------------
  2582 
  2583 *** Document preparation ***
  2584 
  2585 * greatly simplified document preparation setup, including more
  2586 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2587 instructive isatool mkdir; users should basically be able to get
  2588 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2589 users may run a separate document processing stage manually like this:
  2590 "isatool usedir -D output HOL Test && isatool document Test/output";
  2591 
  2592 * theory dependency graph may now be incorporated into documents;
  2593 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2594 with \includegraphics of LaTeX;
  2595 
  2596 * proper spacing of consecutive markup elements, especially text
  2597 blocks after section headings;
  2598 
  2599 * support bold style (for single symbols only), input syntax is like
  2600 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2601 
  2602 * \<bullet> is now output as bold \cdot by default, which looks much
  2603 better in printed text;
  2604 
  2605 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2606 note that these symbols are currently unavailable in Proof General /
  2607 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2608 
  2609 * isatool latex no longer depends on changed TEXINPUTS, instead
  2610 isatool document copies the Isabelle style files to the target
  2611 location;
  2612 
  2613 
  2614 *** Isar ***
  2615 
  2616 * Pure/Provers: improved proof by cases and induction;
  2617   - 'case' command admits impromptu naming of parameters (such as
  2618     "case (Suc n)");
  2619   - 'induct' method divinates rule instantiation from the inductive
  2620     claim; no longer requires excessive ?P bindings for proper
  2621     instantiation of cases;
  2622   - 'induct' method properly enumerates all possibilities of set/type
  2623     rules; as a consequence facts may be also passed through *type*
  2624     rules without further ado;
  2625   - 'induct' method now derives symbolic cases from the *rulified*
  2626     rule (before it used to rulify cases stemming from the internal
  2627     atomized version); this means that the context of a non-atomic
  2628     statement becomes is included in the hypothesis, avoiding the
  2629     slightly cumbersome show "PROP ?case" form;
  2630   - 'induct' may now use elim-style induction rules without chaining
  2631     facts, using ``missing'' premises from the goal state; this allows
  2632     rules stemming from inductive sets to be applied in unstructured
  2633     scripts, while still benefitting from proper handling of non-atomic
  2634     statements; NB: major inductive premises need to be put first, all
  2635     the rest of the goal is passed through the induction;
  2636   - 'induct' proper support for mutual induction involving non-atomic
  2637     rule statements (uses the new concept of simultaneous goals, see
  2638     below);
  2639   - append all possible rule selections, but only use the first
  2640     success (no backtracking);
  2641   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2642   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2643   - added 'print_induct_rules' (covered by help item in recent Proof
  2644     General versions);
  2645   - moved induct/cases attributes to Pure, methods to Provers;
  2646   - generic method setup instantiated for FOL and HOL;
  2647 
  2648 * Pure: support multiple simultaneous goal statements, for example
  2649 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2650 meta-level mechanism, this acts as if several individual goals had
  2651 been stated separately; in particular common proof methods need to be
  2652 repeated in order to cover all claims; note that a single elimination
  2653 step is *not* sufficient to establish the two conjunctions, so this
  2654 fails:
  2655 
  2656   assume "A & B" then have A and B ..   (*".." fails*)
  2657 
  2658 better use "obtain" in situations as above; alternative refer to
  2659 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2660 
  2661 * Pure: proper integration with ``locales''; unlike the original
  2662 version by Florian Kammller, Isar locales package high-level proof
  2663 contexts rather than raw logical ones (e.g. we admit to include
  2664 attributes everywhere); operations on locales include merge and
  2665 rename; support for implicit arguments (``structures''); simultaneous
  2666 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2667 some examples;
  2668 
  2669 * Pure: the following commands have been ``localized'', supporting a
  2670 target locale specification "(in name)": 'lemma', 'theorem',
  2671 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2672 stored both within the locale and at the theory level (exported and
  2673 qualified by the locale name);
  2674 
  2675 * Pure: theory goals may now be specified in ``long'' form, with
  2676 ad-hoc contexts consisting of arbitrary locale elements. for example
  2677 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2678 definitions may be given, too); the result is a meta-level rule with
  2679 the context elements being discharged in the obvious way;
  2680 
  2681 * Pure: new proof command 'using' allows to augment currently used
  2682 facts after a goal statement ('using' is syntactically analogous to
  2683 'apply', but acts on the goal's facts only); this allows chained facts
  2684 to be separated into parts given before and after a claim, as in
  2685 ``from a and b have C using d and e <proof>'';
  2686 
  2687 * Pure: renamed "antecedent" case to "rule_context";
  2688 
  2689 * Pure: new 'judgment' command records explicit information about the
  2690 object-logic embedding (used by several tools internally); no longer
  2691 use hard-wired "Trueprop";
  2692 
  2693 * Pure: added 'corollary' command;
  2694 
  2695 * Pure: fixed 'token_translation' command;
  2696 
  2697 * Pure: removed obsolete 'exported' attribute;
  2698 
  2699 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2700 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2701 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2702 
  2703 * Pure: method 'atomize' presents local goal premises as object-level
  2704 statements (atomic meta-level propositions); setup controlled via
  2705 rewrite rules declarations of 'atomize' attribute; example
  2706 application: 'induct' method with proper rule statements in improper
  2707 proof *scripts*;
  2708 
  2709 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2710 now consider the syntactic context of assumptions, giving a better
  2711 chance to get type-inference of the arguments right (this is
  2712 especially important for locales);
  2713 
  2714 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2715 mode;
  2716 
  2717 * Pure/obtain: the formal conclusion "thesis", being marked as
  2718 ``internal'', may no longer be reference directly in the text;
  2719 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2720 situations;
  2721 
  2722 * Pure: generic 'sym' attribute which declares a rule both as pure
  2723 'elim?' and for the 'symmetric' operation;
  2724 
  2725 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2726 text; the fixed correlation with particular command syntax has been
  2727 discontinued;
  2728 
  2729 * Pure: new method 'rules' is particularly well-suited for proof
  2730 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2731 but often produces more compact proof terms with less detours;
  2732 
  2733 * Pure/Provers/classical: simplified integration with pure rule
  2734 attributes and methods; the classical "intro?/elim?/dest?"
  2735 declarations coincide with the pure ones; the "rule" method no longer
  2736 includes classically swapped intros; "intro" and "elim" methods no
  2737 longer pick rules from the context; also got rid of ML declarations
  2738 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2739 INCOMPATIBILITY;
  2740 
  2741 * Provers/classical: attribute 'swapped' produces classical inversions
  2742 of introduction rules;
  2743 
  2744 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2745 rules instead of full simplifier context; 'iff' attribute handles
  2746 conditional rules;
  2747 
  2748 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2749 
  2750 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2751 "(permissive)" option to recover old behavior;
  2752 
  2753 * HOL: 'inductive' no longer features separate (collective) attributes
  2754 for 'intros' (was found too confusing);
  2755 
  2756 * HOL: properly declared induction rules less_induct and
  2757 wf_induct_rule;
  2758 
  2759 
  2760 *** HOL ***
  2761 
  2762 * HOL: moved over to sane numeral syntax; the new policy is as
  2763 follows:
  2764 
  2765   - 0 and 1 are polymorphic constants, which are defined on any
  2766   numeric type (nat, int, real etc.);
  2767 
  2768   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2769   binary representation internally;
  2770 
  2771   - type nat has special constructor Suc, and generally prefers Suc 0
  2772   over 1::nat and Suc (Suc 0) over 2::nat;
  2773 
  2774 This change may cause significant problems of INCOMPATIBILITY; here
  2775 are some hints on converting existing sources:
  2776 
  2777   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2778   entities, so expressions involving "-" (unary or binary minus) need
  2779   to be spaced properly;
  2780 
  2781   - existing occurrences of "1" may need to be constraint "1::nat" or
  2782   even replaced by Suc 0; similar for old "2";
  2783 
  2784   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2785 
  2786   - remove all special provisions on numerals in proofs;
  2787 
  2788 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2789 representation (depends on bin_arith_simps in the default context);
  2790 
  2791 * HOL: symbolic syntax for x^2 (numeral 2);
  2792 
  2793 * HOL: the class of all HOL types is now called "type" rather than
  2794 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2795 in axclass/classes, instance/arities, and (usually rare) occurrences
  2796 in typings (of consts etc.); internally the class is called
  2797 "HOL.type", ML programs should refer to HOLogic.typeS;
  2798 
  2799 * HOL/record package improvements:
  2800   - new derived operations "fields" to build a partial record section,
  2801     "extend" to promote a fixed record to a record scheme, and
  2802     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2803     declared as simp by default;
  2804   - shared operations ("more", "fields", etc.) now need to be always
  2805     qualified) --- potential INCOMPATIBILITY;
  2806   - removed "make_scheme" operations (use "make" with "extend") --
  2807     INCOMPATIBILITY;
  2808   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2809   - provides cases/induct rules for use with corresponding Isar
  2810     methods (for concrete records, record schemes, concrete more
  2811     parts, and schematic more parts -- in that order);
  2812   - internal definitions directly based on a light-weight abstract
  2813     theory of product types over typedef rather than datatype;
  2814 
  2815 * HOL: generic code generator for generating executable ML code from
  2816 specifications; specific support for HOL constructs such as inductive
  2817 datatypes and sets, as well as recursive functions; can be invoked
  2818 via 'generate_code' theory section;
  2819 
  2820 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2821 
  2822 * HOL: consolidated and renamed several theories.  In particular:
  2823         Ord.thy has been absorbed into HOL.thy
  2824         String.thy has been absorbed into List.thy
  2825 
  2826 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2827 (beware of argument permutation!);
  2828 
  2829 * HOL: linorder_less_split superseded by linorder_cases;
  2830 
  2831 * HOL/List: "nodups" renamed to "distinct";
  2832 
  2833 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2834 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2835   - Ex_def has changed, now need to use some_eq_ex
  2836 
  2837 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2838 in this (rare) case use:
  2839 
  2840   delSWrapper "split_all_tac"
  2841   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2842 
  2843 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2844 MAY FAIL;
  2845 
  2846 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2847 Isabelle's type classes, ^ on functions and relations has too general
  2848 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2849 necessary to attach explicit type constraints;
  2850 
  2851 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2852 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2853 renamed accordingly (eg "compI" -> "rel_compI").
  2854 
  2855 * HOL: syntax translations now work properly with numerals and records
  2856 expressions;
  2857 
  2858 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2859 of "lam" -- INCOMPATIBILITY;
  2860 
  2861 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2862 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2863 renamed "Product_Type.unit";
  2864 
  2865 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2866 
  2867 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2868 the "cases" method);
  2869 
  2870 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2871 Florian Kammller);
  2872 
  2873 * HOL/IMP: updated and converted to new-style theory format; several
  2874 parts turned into readable document, with proper Isar proof texts and
  2875 some explanations (by Gerwin Klein);
  2876 
  2877 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2878 
  2879 * HOL-Hyperreal is now a logic image;
  2880 
  2881 
  2882 *** HOLCF ***
  2883 
  2884 * Isar: consts/constdefs supports mixfix syntax for continuous
  2885 operations;
  2886 
  2887 * Isar: domain package adapted to new-style theory format, e.g. see
  2888 HOLCF/ex/Dnat.thy;
  2889 
  2890 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2891 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2892 lift.induct_tac, always use UU instead of Undef;
  2893 
  2894 * HOLCF/IMP: updated and converted to new-style theory;
  2895 
  2896 
  2897 *** ZF ***
  2898 
  2899 * Isar: proper integration of logic-specific tools and packages,
  2900 including theory commands '(co)inductive', '(co)datatype',
  2901 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2902 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2903 
  2904 * theory Main no longer includes AC; for the Axiom of Choice, base
  2905 your theory on Main_ZFC;
  2906 
  2907 * the integer library now covers quotients and remainders, with many
  2908 laws relating division to addition, multiplication, etc.;
  2909 
  2910 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2911 typeless version of the formalism;
  2912 
  2913 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2914 format;
  2915 
  2916 * ZF/Induct: new directory for examples of inductive definitions,
  2917 including theory Multiset for multiset orderings; converted to
  2918 new-style theory format;
  2919 
  2920 * ZF: many new theorems about lists, ordinals, etc.;
  2921 
  2922 
  2923 *** General ***
  2924 
  2925 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2926 variable proof controls level of detail: 0 = no proofs (only oracle
  2927 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2928 also ref manual for further ML interfaces;
  2929 
  2930 * Pure/axclass: removed obsolete ML interface
  2931 goal_subclass/goal_arity;
  2932 
  2933 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2934 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2935 separate tokens, so expressions involving minus need to be spaced
  2936 properly;
  2937 
  2938 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2939 rather than "infixl" or "infixr";
  2940 
  2941 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2942 sort constraint specifications in type inference; e.g. "x::_::foo"
  2943 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2944 type variable);
  2945 
  2946 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2947 control output of nested => (types); the default behavior is
  2948 "type_brackets";
  2949 
  2950 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2951 tokens into AST constants;
  2952 
  2953 * Pure/syntax: prefer later declarations of translations and print
  2954 translation functions; potential INCOMPATIBILITY: need to reverse
  2955 multiple declarations for same syntax element constant;
  2956 
  2957 * Pure/show_hyps reset by default (in accordance to existing Isar
  2958 practice);
  2959 
  2960 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2961 addSafter;
  2962 
  2963 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2964 as well;
  2965 
  2966 * system: tested support for MacOS X; should be able to get Isabelle +
  2967 Proof General to work in a plain Terminal after installing Poly/ML
  2968 (e.g. from the Isabelle distribution area) and GNU bash alone
  2969 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2970 support requires further installations, e.g. from
  2971 http://fink.sourceforge.net/);
  2972 
  2973 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2974 
  2975 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2976 of 40 MB), cf. ML_OPTIONS;
  2977 
  2978 * system: Proof General keywords specification is now part of the
  2979 Isabelle distribution (see etc/isar-keywords.el);
  2980 
  2981 * system: support for persistent Proof General sessions (refrain from
  2982 outdating all loaded theories on startup); user may create writable
  2983 logic images like this: ``isabelle -q HOL Test'';
  2984 
  2985 * system: smart selection of Isabelle process versus Isabelle
  2986 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2987 run both "isabelle" and "Isabelle" even if file names are badly
  2988 damaged (executable inspects the case of the first letter of its own
  2989 name); added separate "isabelle-process" and "isabelle-interface";
  2990 
  2991 * system: refrain from any attempt at filtering input streams; no
  2992 longer support ``8bit'' encoding of old isabelle font, instead proper
  2993 iso-latin characters may now be used; the related isatools
  2994 "symbolinput" and "nonascii" have disappeared as well;
  2995 
  2996 * system: removed old "xterm" interface (the print modes "xterm" and
  2997 "xterm_color" are still available for direct use in a suitable
  2998 terminal);
  2999 
  3000 
  3001 
  3002 New in Isabelle99-2 (February 2001)
  3003 -----------------------------------
  3004 
  3005 *** Overview of INCOMPATIBILITIES ***
  3006 
  3007 * HOL: please note that theories in the Library and elsewhere often use the
  3008 new-style (Isar) format; to refer to their theorems in an ML script you must
  3009 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3010 
  3011 * HOL: inductive package no longer splits induction rule aggressively,
  3012 but only as far as specified by the introductions given; the old
  3013 format may be recovered via ML function complete_split_rule or attribute
  3014 'split_rule (complete)';
  3015 
  3016 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3017 gfp_Tarski to gfp_unfold;
  3018 
  3019 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3020 
  3021 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3022 relation); infix "^^" has been renamed "``"; infix "``" has been
  3023 renamed "`"; "univalent" has been renamed "single_valued";
  3024 
  3025 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3026 operation;
  3027 
  3028 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3029 
  3030 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3031 
  3032 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3033 consequence, it is no longer monotonic wrt. the local goal context
  3034 (which is now passed through the inductive cases);
  3035 
  3036 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3037 \<gg> to \<ggreater>;
  3038 
  3039 
  3040 *** Document preparation ***
  3041 
  3042 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3043 available: are "it" for near math-mode best-style output, "sl" for
  3044 slanted text style, and "tt" for plain type-writer; if no
  3045 \isabellestyle command is given, output is according to slanted
  3046 type-writer);
  3047 
  3048 * support sub/super scripts (for single symbols only), input syntax is
  3049 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3050 
  3051 * some more standard symbols; see Appendix A of the system manual for
  3052 the complete list of symbols defined in isabellesym.sty;
  3053 
  3054 * improved isabelle style files; more abstract symbol implementation
  3055 (should now use \isamath{...} and \isatext{...} in custom symbol
  3056 definitions);
  3057 
  3058 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3059 state; Note that presentation of goal states does not conform to
  3060 actual human-readable proof documents.  Please do not include goal
  3061 states into document output unless you really know what you are doing!
  3062 
  3063 * proper indentation of antiquoted output with proportional LaTeX
  3064 fonts;
  3065 
  3066 * no_document ML operator temporarily disables LaTeX document
  3067 generation;
  3068 
  3069 * isatool unsymbolize tunes sources for plain ASCII communication;
  3070 
  3071 
  3072 *** Isar ***
  3073 
  3074 * Pure: Isar now suffers initial goal statements to contain unbound
  3075 schematic variables (this does not conform to actual readable proof
  3076 documents, due to unpredictable outcome and non-compositional proof
  3077 checking); users who know what they are doing may use schematic goals
  3078 for Prolog-style synthesis of proven results;
  3079 
  3080 * Pure: assumption method (an implicit finishing) now handles actual
  3081 rules as well;
  3082 
  3083 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3084 initial goal, declare "that" only as Pure intro (only for single
  3085 steps); the "that" rule assumption may now be involved in implicit
  3086 finishing, thus ".." becomes a feasible for trivial obtains;
  3087 
  3088 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3089 instance proofs may be performed by "..";
  3090 
  3091 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3092 statements as well;
  3093 
  3094 * Pure: more robust selection of calculational rules;
  3095 
  3096 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3097 rule (as well as the assumption rule);
  3098 
  3099 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3100 lemmas, using the graph browser tool;
  3101 
  3102 * Pure: predict failure of "show" in interactive mode;
  3103 
  3104 * Pure: 'thms_containing' now takes actual terms as arguments;
  3105 
  3106 * HOL: improved method 'induct' --- now handles non-atomic goals
  3107 (potential INCOMPATIBILITY); tuned error handling;
  3108 
  3109 * HOL: cases and induct rules now provide explicit hints about the
  3110 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3111 any remaining facts are inserted into the goal verbatim;
  3112 
  3113 * HOL: local contexts (aka cases) may now contain term bindings as
  3114 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3115 the result to be shown in each case;
  3116 
  3117 * HOL: added 'recdef_tc' command;
  3118 
  3119 * isatool convert assists in eliminating legacy ML scripts;
  3120 
  3121 
  3122 *** HOL ***
  3123 
  3124 * HOL/Library: a collection of generic theories to be used together
  3125 with main HOL; the theory loader path already includes this directory
  3126 by default; the following existing theories have been moved here:
  3127 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3128 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3129 
  3130 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3131 modelling and verification task performed in Isabelle/HOL +
  3132 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3133 
  3134 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3135 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3136 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3137 'domain', this makes the theory consistent with mathematical
  3138 literature;
  3139 
  3140 * HOL basics: added overloaded operations "inverse" and "divide"
  3141 (infix "/"), syntax for generic "abs" operation, generic summation
  3142 operator \<Sum>;
  3143 
  3144 * HOL/typedef: simplified package, provide more useful rules (see also
  3145 HOL/subset.thy);
  3146 
  3147 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3148 now expressed as a proper nested rule (old-style tactic scripts may
  3149 require atomize_strip_tac to cope with non-atomic premises);
  3150 
  3151 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3152 to "split_conv" (old name still available for compatibility);
  3153 
  3154 * HOL: improved concrete syntax for strings (e.g. allows translation
  3155 rules with string literals);
  3156 
  3157 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3158  and Fleuriot's mechanization of analysis, including the transcendental
  3159  functions for the reals;
  3160 
  3161 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3162 
  3163 
  3164 *** CTT ***
  3165 
  3166 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3167 "lam" is displayed as TWO lambda-symbols
  3168 
  3169 * CTT: theory Main now available, containing everything (that is, Bool
  3170 and Arith);
  3171 
  3172 
  3173 *** General ***
  3174 
  3175 * Pure: the Simplifier has been implemented properly as a derived rule
  3176 outside of the actual kernel (at last!); the overall performance
  3177 penalty in practical applications is about 50%, while reliability of
  3178 the Isabelle inference kernel has been greatly improved;
  3179 
  3180 * print modes "brackets" and "no_brackets" control output of nested =>
  3181 (types) and ==> (props); the default behaviour is "brackets";
  3182 
  3183 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3184 as assumptions as well;
  3185 
  3186 * system: support Poly/ML 4.0;
  3187 
  3188 * system: isatool install handles KDE version 1 or 2;
  3189 
  3190 
  3191 
  3192 New in Isabelle99-1 (October 2000)
  3193 ----------------------------------
  3194 
  3195 *** Overview of INCOMPATIBILITIES ***
  3196 
  3197 * HOL: simplification of natural numbers is much changed; to partly
  3198 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3199 issue the following ML commands:
  3200 
  3201   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3202   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3203 
  3204 * HOL: simplification no longer dives into case-expressions; this is
  3205 controlled by "t.weak_case_cong" for each datatype t;
  3206 
  3207 * HOL: nat_less_induct renamed to less_induct;
  3208 
  3209 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3210 fixsome to patch .thy and .ML sources automatically;
  3211 
  3212   select_equality  -> some_equality
  3213   select_eq_Ex     -> some_eq_ex
  3214   selectI2EX       -> someI2_ex
  3215   selectI2         -> someI2
  3216   selectI          -> someI
  3217   select1_equality -> some1_equality
  3218   Eps_sym_eq       -> some_sym_eq_trivial
  3219   Eps_eq           -> some_eq_trivial
  3220 
  3221 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3222 
  3223 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3224 instead);
  3225 
  3226 * HOL: the recursion equations generated by 'recdef' are now called
  3227 f.simps instead of f.rules;
  3228 
  3229 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3230 
  3231 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3232 sometimes be needed;
  3233 
  3234 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3235 
  3236 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3237 
  3238 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3239 product is now "<*>" instead of "Times"; the lexicographic product is
  3240 now "<*lex*>" instead of "**";
  3241 
  3242 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3243 of main HOL, but was unused); better use HOL's datatype package;
  3244 
  3245 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3246 the old syntax may be recovered as follows:
  3247 
  3248   syntax (symbols)
  3249     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3250       (infixl "\\<oplus>" 100)
  3251 
  3252 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3253 
  3254 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3255 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3256 internally;
  3257 
  3258 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3259 changed from A/r to A//r;
  3260 
  3261 * ZF: new treatment of arithmetic (nat & int) may break some old
  3262 proofs;
  3263 
  3264 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3265 rulify -> rule_format, elimify -> elim_format, ...);
  3266 
  3267 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3268 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3269 should have to change intro!! to intro? only); replaced "delrule" by
  3270 "rule del";
  3271 
  3272 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3273 
  3274 * Provers: strengthened force_tac by using new first_best_tac;
  3275 
  3276 * LaTeX document preparation: several changes of isabelle.sty (see
  3277 lib/texinputs);
  3278 
  3279 
  3280 *** Document preparation ***
  3281 
  3282 * formal comments (text blocks etc.) in new-style theories may now
  3283 contain antiquotations of thm/prop/term/typ/text to be presented
  3284 according to latex print mode; concrete syntax is like this:
  3285 @{term[show_types] "f(x) = a + x"};
  3286 
  3287 * isatool mkdir provides easy setup of Isabelle session directories,
  3288 including proper document sources;
  3289 
  3290 * generated LaTeX sources are now deleted after successful run
  3291 (isatool document -c); may retain a copy somewhere else via -D option
  3292 of isatool usedir;
  3293 
  3294 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3295 style files, achieving self-contained LaTeX sources and simplifying
  3296 LaTeX debugging;
  3297 
  3298 * old-style theories now produce (crude) LaTeX output as well;
  3299 
  3300 * browser info session directories are now self-contained (may be put
  3301 on WWW server seperately); improved graphs of nested sessions; removed
  3302 graph for 'all sessions';
  3303 
  3304 * several improvements in isabelle style files; \isabellestyle{it}
  3305 produces fake math mode output; \isamarkupheader is now \section by
  3306 default; see lib/texinputs/isabelle.sty etc.;
  3307 
  3308 
  3309 *** Isar ***
  3310 
  3311 * Isar/Pure: local results and corresponding term bindings are now
  3312 subject to Hindley-Milner polymorphism (similar to ML); this
  3313 accommodates incremental type-inference very nicely;
  3314 
  3315 * Isar/Pure: new derived language element 'obtain' supports
  3316 generalized existence reasoning;
  3317 
  3318 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3319 support accumulation of results, without applying any rules yet;
  3320 useful to collect intermediate results without explicit name
  3321 references, and for use with transitivity rules with more than 2
  3322 premises;
  3323 
  3324 * Isar/Pure: scalable support for case-analysis type proofs: new
  3325 'case' language element refers to local contexts symbolically, as
  3326 produced by certain proof methods; internally, case names are attached
  3327 to theorems as "tags";
  3328 
  3329 * Isar/Pure: theory command 'hide' removes declarations from
  3330 class/type/const name spaces;
  3331 
  3332 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3333 indicate potential overloading;
  3334 
  3335 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3336 
  3337 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3338 "{a,b,c}" instead of {a,b,c};
  3339 
  3340 * Isar/Pure now provides its own version of intro/elim/dest
  3341 attributes; useful for building new logics, but beware of confusion
  3342 with the version in Provers/classical;
  3343 
  3344 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3345 case name 'antecedent';
  3346 
  3347 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3348 to the current context is now done automatically);
  3349 
  3350 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3351 for definining proof methods in ML;
  3352 
  3353 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3354 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3355 most cases, one should have to change intro!! to intro? only);
  3356 replaced "delrule" by "rule del";
  3357 
  3358 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3359 'symmetric' attribute (the latter supercedes [RS sym]);
  3360 
  3361 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3362 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3363 well (including splits);
  3364 
  3365 * Isar/Provers: Simplifier and Classical methods now support all kind
  3366 of modifiers used in the past, including 'cong', 'iff', etc.
  3367 
  3368 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3369 of Simplifier and Classical reasoner);
  3370 
  3371 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3372 now support named cases; major packages (inductive, datatype, primrec,
  3373 recdef) support case names and properly name parameters;
  3374 
  3375 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3376 monotonicity conditions are extracted to be proven at end of
  3377 calculations;
  3378 
  3379 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3380 method anyway;
  3381 
  3382 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3383 split_if split_if_asm; datatype package provides theorems foo.splits =
  3384 foo.split foo.split_asm for each datatype;
  3385 
  3386 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3387 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3388 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3389 use "(cases (simplified))" method in proper proof texts);
  3390 
  3391 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3392 
  3393 * Isar: names of theorems etc. may be natural numbers as well;
  3394 
  3395 * Isar: 'pr' command: optional arguments for goals_limit and
  3396 ProofContext.prems_limit; no longer prints theory contexts, but only
  3397 proof states;
  3398 
  3399 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3400 additional print modes to be specified; e.g. "pr(latex)" will print
  3401 proof state according to the Isabelle LaTeX style;
  3402 
  3403 * Isar: improved support for emulating tactic scripts, including proof
  3404 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3405 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3406 (for HOL datatypes);
  3407 
  3408 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3409 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3410 'proof method scripts' have to be in depth-first order;
  3411 
  3412 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3413 
  3414 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3415 should instead use individual commands for printing items
  3416 (print_commands, print_methods etc.);
  3417 
  3418 * Isar: added 'nothing' --- the empty list of theorems;
  3419 
  3420 
  3421 *** HOL ***
  3422 
  3423 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3424 corresponding virtual machine and a specification of its bytecode
  3425 verifier and a lightweight bytecode verifier, including proofs of
  3426 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3427 Cornelia Pusch (see also the homepage of project Bali at
  3428 http://isabelle.in.tum.de/Bali/);
  3429 
  3430 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3431 Clemens Ballarin;
  3432 
  3433 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3434 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3435 Rasmussen;
  3436 
  3437 * HOL/Lattice: fundamental concepts of lattice theory and order
  3438 structures, including duals, properties of bounds versus algebraic
  3439 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3440 Theorem for complete lattices etc.; may also serve as a demonstration
  3441 for abstract algebraic reasoning using axiomatic type classes, and
  3442 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3443 
  3444 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3445 von Oheimb;
  3446 
  3447 * HOL/IMPP: extension of IMP with local variables and mutually
  3448 recursive procedures, by David von Oheimb;
  3449 
  3450 * HOL/Lambda: converted into new-style theory and document;
  3451 
  3452 * HOL/ex/Multiquote: example of multiple nested quotations and
  3453 anti-quotations -- basically a generalized version of de-Bruijn
  3454 representation; very useful in avoiding lifting of operations;
  3455 
  3456 * HOL/record: added general record equality rule to simpset; fixed
  3457 select-update simplification procedure to handle extended records as
  3458 well; admit "r" as field name;
  3459 
  3460 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3461 other numeric types and also as the identity of groups, rings, etc.;
  3462 
  3463 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3464 Types nat and int belong to this axclass;
  3465 
  3466 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3467    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3468    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3469   two terms #m*u and #n*u are replaced by #(m+n)*u
  3470     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3471   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3472     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3473 
  3474 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3475 powerful prover for predicate logic but knows nothing of clasets; see
  3476 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3477 
  3478 * HOL: new version of "case_tac" subsumes both boolean case split and
  3479 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3480 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3481 
  3482 * HOL: simplification no longer dives into case-expressions: only the
  3483 selector expression is simplified, but not the remaining arms; to
  3484 enable full simplification of case-expressions for datatype t, you may
  3485 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3486 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3487 
  3488 * HOL/recdef: the recursion equations generated by 'recdef' for
  3489 function 'f' are now called f.simps instead of f.rules; if all
  3490 termination conditions are proved automatically, these simplification
  3491 rules are added to the simpset, as in primrec; rules may be named
  3492 individually as well, resulting in a separate list of theorems for
  3493 each equation;
  3494 
  3495 * HOL/While is a new theory that provides a while-combinator. It
  3496 permits the definition of tail-recursive functions without the
  3497 provision of a termination measure. The latter is necessary once the
  3498 invariant proof rule for while is applied.
  3499 
  3500 * HOL: new (overloaded) notation for the set of elements below/above
  3501 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3502 
  3503 * HOL: theorems impI, allI, ballI bound as "strip";
  3504 
  3505 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3506 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3507 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3508 
  3509 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3510 
  3511 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3512 main HOL, but was unused);
  3513 
  3514 * HOL: fewer consts declared as global (e.g. have to refer to
  3515 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3516 
  3517 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3518 in case of overlap with user translations (e.g. judgements over
  3519 tuples); (note that the underlying logical represenation is still
  3520 bogus);
  3521 
  3522 
  3523 *** ZF ***
  3524 
  3525 * ZF: simplification automatically cancels common terms in arithmetic
  3526 expressions over nat and int;
  3527 
  3528 * ZF: new treatment of nat to minimize type-checking: all operators
  3529 coerce their operands to a natural number using the function natify,
  3530 making the algebraic laws unconditional;
  3531 
  3532 * ZF: as above, for int: operators coerce their operands to an integer
  3533 using the function intify;
  3534 
  3535 * ZF: the integer library now contains many of the usual laws for the
  3536 orderings, including $<=, and monotonicity laws for $+ and $*;
  3537 
  3538 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3539 simplification;
  3540 
  3541 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3542 to the simplifier and classical reasoner simultaneously;
  3543 
  3544 
  3545 *** General ***
  3546 
  3547 * Provers: blast_tac now handles actual object-logic rules as
  3548 assumptions; note that auto_tac uses blast_tac internally as well;
  3549 
  3550 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3551 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3552 
  3553 * Provers: delrules now handles destruct rules as well (no longer need
  3554 explicit make_elim);
  3555 
  3556 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3557   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3558 use instead the strong form,
  3559   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3560 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3561 from destruct-rules;
  3562 
  3563 * Provers: Simplifier.easy_setup provides a fast path to basic
  3564 Simplifier setup for new object-logics;
  3565 
  3566 * Pure: AST translation rules no longer require constant head on LHS;
  3567 
  3568 * Pure: improved name spaces: ambiguous output is qualified; support
  3569 for hiding of names;
  3570 
  3571 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3572 XSYMBOL_HOME; no longer need to do manual configuration in most
  3573 situations;
  3574 
  3575 * system: compression of ML heaps images may now be controlled via -c
  3576 option of isabelle and isatool usedir (currently only observed by
  3577 Poly/ML);
  3578 
  3579 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3580 useful for remote X11);
  3581 
  3582 * system: provide TAGS file for Isabelle sources;
  3583 
  3584 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3585 order;
  3586 
  3587 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3588 timing flag supersedes proof_timing and Toplevel.trace;
  3589 
  3590 * ML: new combinators |>> and |>>> for incremental transformations
  3591 with secondary results (e.g. certain theory extensions):
  3592 
  3593 * ML: PureThy.add_defs gets additional argument to indicate potential
  3594 overloading (usually false);
  3595 
  3596 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3597 results;
  3598 
  3599 
  3600 
  3601 New in Isabelle99 (October 1999)
  3602 --------------------------------
  3603 
  3604 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3605 
  3606 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3607 are no longer simplified.  (This allows the simplifier to unfold recursive
  3608 functional programs.)  To restore the old behaviour, declare
  3609 
  3610     Delcongs [if_weak_cong];
  3611 
  3612 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3613 complement;
  3614 
  3615 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3616 
  3617 * HOL/datatype: mutual_induct_tac no longer exists --
  3618   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3619 
  3620 * HOL/typedef: fixed type inference for representing set; type
  3621 arguments now have to occur explicitly on the rhs as type constraints;
  3622 
  3623 * ZF: The con_defs part of an inductive definition may no longer refer
  3624 to constants declared in the same theory;
  3625 
  3626 * HOL, ZF: the function mk_cases, generated by the inductive
  3627 definition package, has lost an argument.  To simplify its result, it
  3628 uses the default simpset instead of a supplied list of theorems.
  3629 
  3630 * HOL/List: the constructors of type list are now Nil and Cons;
  3631 
  3632 * Simplifier: the type of the infix ML functions
  3633         setSSolver addSSolver setSolver addSolver
  3634 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3635 for packaging solvers. A solver is created via
  3636         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3637 where the string argument is only a comment.
  3638 
  3639 
  3640 *** Proof tools ***
  3641 
  3642 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3643 decision procedure for linear arithmetic. Currently it is used for
  3644 types `nat', `int', and `real' in HOL (see below); it can, should and
  3645 will be instantiated for other types and logics as well.
  3646 
  3647 * The simplifier now accepts rewrite rules with flexible heads, eg
  3648      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3649   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3650   matching.
  3651 
  3652 
  3653 *** General ***
  3654 
  3655 * New Isabelle/Isar subsystem provides an alternative to traditional
  3656 tactical theorem proving; together with the ProofGeneral/isar user
  3657 interface it offers an interactive environment for developing human
  3658 readable proof documents (Isar == Intelligible semi-automated
  3659 reasoning); for further information see isatool doc isar-ref,
  3660 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3661 
  3662 * improved and simplified presentation of theories: better HTML markup
  3663 (including colors), graph views in several sizes; isatool usedir now
  3664 provides a proper interface for user theories (via -P option); actual
  3665 document preparation based on (PDF)LaTeX is available as well (for
  3666 new-style theories only); see isatool doc system for more information;
  3667 
  3668 * native support for Proof General, both for classic Isabelle and
  3669 Isabelle/Isar;
  3670 
  3671 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3672 using the graph browser tool;
  3673 
  3674 * Isabelle manuals now also available as PDF;
  3675 
  3676 * theory loader rewritten from scratch (may not be fully
  3677 bug-compatible); old loadpath variable has been replaced by show_path,
  3678 add_path, del_path, reset_path functions; new operations such as
  3679 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3680 isatool doc ref);
  3681 
  3682 * improved isatool install: option -k creates KDE application icon,
  3683 option -p DIR installs standalone binaries;
  3684 
  3685 * added ML_PLATFORM setting (useful for cross-platform installations);
  3686 more robust handling of platform specific ML images for SML/NJ;
  3687 
  3688 * the settings environment is now statically scoped, i.e. it is never
  3689 created again in sub-processes invoked from isabelle, isatool, or
  3690 Isabelle;
  3691 
  3692 * path element specification '~~' refers to '$ISABELLE_HOME';
  3693 
  3694 * in locales, the "assumes" and "defines" parts may be omitted if
  3695 empty;
  3696 
  3697 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3698 long arrows);
  3699 
  3700 * new print_mode "HTML";
  3701 
  3702 * new flag show_tags controls display of tags of theorems (which are
  3703 basically just comments that may be attached by some tools);
  3704 
  3705 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3706 mode and goal output format:
  3707 
  3708 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3709 244c244
  3710 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3711 ---
  3712 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3713 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3714 181c181
  3715 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3716 ---
  3717 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3718 
  3719 * function bind_thms stores lists of theorems (cf. bind_thm);
  3720 
  3721 * new shorthand tactics ftac, eatac, datac, fatac;
  3722 
  3723 * qed (and friends) now accept "" as result name; in that case the
  3724 theorem is not stored, but proper checks and presentation of the
  3725 result still apply;
  3726 
  3727 * theorem database now also indexes constants "Trueprop", "all",
  3728 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3729 
  3730 
  3731 *** HOL ***
  3732 
  3733 ** HOL arithmetic **
  3734 
  3735 * There are now decision procedures for linear arithmetic over nat and
  3736 int:
  3737 
  3738 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3739 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3740 are treated as atomic; subformulae not involving type `nat' or `int'
  3741 are ignored; quantified subformulae are ignored unless they are
  3742 positive universal or negative existential. The tactic has to be
  3743 invoked by hand and can be a little bit slow. In particular, the
  3744 running time is exponential in the number of occurrences of `min' and
  3745 `max', and `-' on `nat'.
  3746 
  3747 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3748 (negated) (in)equalities among the premises and the conclusion into
  3749 account (i.e. no compound formulae) and does not know about `min' and
  3750 `max', and `-' on `nat'. It is fast and is used automatically by the
  3751 simplifier.
  3752 
  3753 NB: At the moment, these decision procedures do not cope with mixed
  3754 nat/int formulae where the two parts interact, such as `m < n ==>
  3755 int(m) < int(n)'.
  3756 
  3757 * HOL/Numeral provides a generic theory of numerals (encoded
  3758 efficiently as bit strings); setup for types nat/int/real is in place;
  3759 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3760 int, existing theories and proof scripts may require a few additional
  3761 type constraints;
  3762 
  3763 * integer division and remainder can now be performed on constant
  3764 arguments;
  3765 
  3766 * many properties of integer multiplication, division and remainder
  3767 are now available;
  3768 
  3769 * An interface to the Stanford Validity Checker (SVC) is available through the
  3770 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3771 are proved automatically.  SVC must be installed separately, and its results
  3772 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3773 invocation of the underlying oracle).  For SVC see
  3774   http://verify.stanford.edu/SVC
  3775 
  3776 * IsaMakefile: the HOL-Real target now builds an actual image;
  3777 
  3778 
  3779 ** HOL misc **
  3780 
  3781 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3782 (in Isabelle/Isar) -- by Gertrud Bauer;
  3783 
  3784 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3785 analysis for assembly languages with subtypes;
  3786 
  3787 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3788 -- avoids syntactic ambiguities and treats state, transition, and
  3789 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3790 changed syntax and (many) tactics;
  3791 
  3792 * HOL/inductive: Now also handles more general introduction rules such
  3793   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3794   theorems are now maintained within the theory (maintained via the
  3795   "mono" attribute);
  3796 
  3797 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3798   (using function types) such as
  3799 
  3800   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3801 
  3802 * HOL/record: record_simproc (part of the default simpset) takes care
  3803 of selectors applied to updated records; record_split_tac is no longer
  3804 part of the default claset; update_defs may now be removed from the
  3805 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3806 
  3807   claset_ref () := claset() addSWrapper record_split_wrapper;
  3808   Delsimprocs [record_simproc]
  3809 
  3810 * HOL/typedef: fixed type inference for representing set; type
  3811 arguments now have to occur explicitly on the rhs as type constraints;
  3812 
  3813 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3814 names rather than an ML expression;
  3815 
  3816 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3817 supplied later.  Program schemes can be defined, such as
  3818     "While B C s = (if B s then While B C (C s) else s)"
  3819 where the well-founded relation can be chosen after B and C have been given.
  3820 
  3821 * HOL/List: the constructors of type list are now Nil and Cons;
  3822 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3823 course, ML tools referring to List.list.op # etc. have to be adapted;
  3824 
  3825 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3826 disabled by default; run isabelle with option -m HOL to get back to
  3827 the original Gordon/HOL-style output;
  3828 
  3829 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3830 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3831 
  3832 * HOL basic syntax simplified (more orthogonal): all variants of
  3833 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3834 Eps operator is provided as well: "SOME x. P[x]";
  3835 
  3836 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3837 
  3838 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3839 thus available for user theories;
  3840 
  3841 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3842 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3843 time;
  3844 
  3845 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3846 several times and then mp;
  3847 
  3848 
  3849 *** LK ***
  3850 
  3851 * the notation <<...>> is now available as a notation for sequences of
  3852 formulas;
  3853 
  3854 * the simplifier is now installed
  3855 
  3856 * the axiom system has been generalized (thanks to Soren Heilmann)
  3857 
  3858 * the classical reasoner now has a default rule database
  3859 
  3860 
  3861 *** ZF ***
  3862 
  3863 * new primrec section allows primitive recursive functions to be given
  3864 directly (as in HOL) over datatypes and the natural numbers;
  3865 
  3866 * new tactics induct_tac and exhaust_tac for induction (or case
  3867 analysis) over datatypes and the natural numbers;
  3868 
  3869 * the datatype declaration of type T now defines the recursor T_rec;
  3870 
  3871 * simplification automatically does freeness reasoning for datatype
  3872 constructors;
  3873 
  3874 * automatic type-inference, with AddTCs command to insert new
  3875 type-checking rules;
  3876 
  3877 * datatype introduction rules are now added as Safe Introduction rules
  3878 to the claset;
  3879 
  3880 * the syntax "if P then x else y" is now available in addition to
  3881 if(P,x,y);
  3882 
  3883 
  3884 *** Internal programming interfaces ***
  3885 
  3886 * tuned simplifier trace output; new flag debug_simp;
  3887 
  3888 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3889 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3890 
  3891 * AxClass.axclass_tac lost the theory argument;
  3892 
  3893 * tuned current_goals_markers semantics: begin / end goal avoids
  3894 printing empty lines;
  3895 
  3896 * removed prs and prs_fn hook, which was broken because it did not
  3897 include \n in its semantics, forcing writeln to add one
  3898 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3899 string -> unit if you really want to output text without newline;
  3900 
  3901 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3902 plain output, interface builders may have to enable 'isabelle_font'
  3903 mode to get Isabelle font glyphs as before;
  3904 
  3905 * refined token_translation interface; INCOMPATIBILITY: output length
  3906 now of type real instead of int;
  3907 
  3908 * theory loader actions may be traced via new ThyInfo.add_hook
  3909 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3910 your own database of information attached to *whole* theories -- as
  3911 opposed to intra-theory data slots offered via TheoryDataFun;
  3912 
  3913 * proper handling of dangling sort hypotheses (at last!);
  3914 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3915 extra sort hypotheses that can be witnessed from the type signature;
  3916 the force_strip_shyps flag is gone, any remaining shyps are simply
  3917 left in the theorem (with a warning issued by strip_shyps_warning);
  3918 
  3919 
  3920 
  3921 New in Isabelle98-1 (October 1998)
  3922 ----------------------------------
  3923 
  3924 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3925 
  3926 * several changes of automated proof tools;
  3927 
  3928 * HOL: major changes to the inductive and datatype packages, including
  3929 some minor incompatibilities of theory syntax;
  3930 
  3931 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3932 called `inj_on';
  3933 
  3934 * HOL: removed duplicate thms in Arith:
  3935   less_imp_add_less  should be replaced by  trans_less_add1
  3936   le_imp_add_le      should be replaced by  trans_le_add1
  3937 
  3938 * HOL: unary minus is now overloaded (new type constraints may be
  3939 required);
  3940 
  3941 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3942 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3943 now taken as an integer constant.
  3944 
  3945 * Pure: ML function 'theory_of' renamed to 'theory';
  3946 
  3947 
  3948 *** Proof tools ***
  3949 
  3950 * Simplifier:
  3951   1. Asm_full_simp_tac is now more aggressive.
  3952      1. It will sometimes reorient premises if that increases their power to
  3953         simplify.
  3954      2. It does no longer proceed strictly from left to right but may also
  3955         rotate premises to achieve further simplification.
  3956      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3957      old Asm_full_simp_tac in that it does not rotate premises.
  3958   2. The simplifier now knows a little bit about nat-arithmetic.
  3959 
  3960 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3961 allows for selected deletion of wrappers, by introduction of names for
  3962 wrapper functionals.  This implies that addbefore, addSbefore,
  3963 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3964 and that adding two tactics with the same name overwrites the first
  3965 one (emitting a warning).
  3966   type wrapper = (int -> tactic) -> (int -> tactic)
  3967   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3968   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3969   delWrapper, delSWrapper: claset *  string            -> claset
  3970   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3971 
  3972 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3973 semantics; addbefore now affects only the unsafe part of step_tac
  3974 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3975 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3976 by Force_tac;
  3977 
  3978 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3979 compWrapper; added safe wrapper (and access functions for it);
  3980 
  3981 * HOL/split_all_tac is now much faster and fails if there is nothing
  3982 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3983 and the names of the automatically generated variables have changed.
  3984 split_all_tac has moved within claset() from unsafe wrappers to safe
  3985 wrappers, which means that !!-bound variables are split much more
  3986 aggressively, and safe_tac and clarify_tac now split such variables.
  3987 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3988 Note: the same holds for record_split_tac, which does the job of
  3989 split_all_tac for record fields.
  3990 
  3991 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3992 permanently to the default simpset using Addsplits just like
  3993 Addsimps. They can be removed via Delsplits just like
  3994 Delsimps. Lower-case versions are also available.
  3995 
  3996 * HOL/Simplifier: The rule split_if is now part of the default
  3997 simpset. This means that the simplifier will eliminate all occurrences
  3998 of if-then-else in the conclusion of a goal. To prevent this, you can
  3999 either remove split_if completely from the default simpset by
  4000 `Delsplits [split_if]' or remove it in a specific call of the
  4001 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4002 other case splitting rules to/from the default simpset: every datatype
  4003 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4004 t is the name of the datatype).
  4005 
  4006 * Classical reasoner / Simplifier combination: new force_tac (and
  4007 derivatives Force_tac, force) combines rewriting and classical
  4008 reasoning (and whatever other tools) similarly to auto_tac, but is
  4009 aimed to solve the given subgoal completely.
  4010 
  4011 
  4012 *** General ***
  4013 
  4014 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4015 and `goalw': the theory is no longer needed as an explicit argument -
  4016 the current theory context is used; assumptions are no longer returned
  4017 at the ML-level unless one of them starts with ==> or !!; it is
  4018 recommended to convert to these new commands using isatool fixgoal
  4019 (backup your sources first!);
  4020 
  4021 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4022 the current theory context, and 'theory' to lookup stored theories;
  4023 
  4024 * new theory section 'locale' for declaring constants, assumptions and
  4025 definitions that have local scope;
  4026 
  4027 * new theory section 'nonterminals' for purely syntactic types;
  4028 
  4029 * new theory section 'setup' for generic ML setup functions
  4030 (e.g. package initialization);
  4031 
  4032 * the distribution now includes Isabelle icons: see
  4033 lib/logo/isabelle-{small,tiny}.xpm;
  4034 
  4035 * isatool install - install binaries with absolute references to
  4036 ISABELLE_HOME/bin;
  4037 
  4038 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4039 
  4040 * print mode 'emacs' reserved for Isamode;
  4041 
  4042 * support multiple print (ast) translations per constant name;
  4043 
  4044 * theorems involving oracles are now printed with a suffixed [!];
  4045 
  4046 
  4047 *** HOL ***
  4048 
  4049 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4050 
  4051 * HOL/inductive package reorganized and improved: now supports mutual
  4052 definitions such as
  4053 
  4054   inductive EVEN ODD
  4055     intrs
  4056       null "0 : EVEN"
  4057       oddI "n : EVEN ==> Suc n : ODD"
  4058       evenI "n : ODD ==> Suc n : EVEN"
  4059 
  4060 new theorem list "elims" contains an elimination rule for each of the
  4061 recursive sets; inductive definitions now handle disjunctive premises
  4062 correctly (also ZF);
  4063 
  4064 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4065 "mutual_induct" no longer exists - the induction rule is always
  4066 contained in "induct";
  4067 
  4068 
  4069 * HOL/datatype package re-implemented and greatly improved: now
  4070 supports mutually recursive datatypes such as
  4071 
  4072   datatype
  4073     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4074             | SUM ('a aexp) ('a aexp)
  4075             | DIFF ('a aexp) ('a aexp)
  4076             | NUM 'a
  4077   and
  4078     'a bexp = LESS ('a aexp) ('a aexp)
  4079             | AND ('a bexp) ('a bexp)
  4080             | OR ('a bexp) ('a bexp)
  4081 
  4082 as well as indirectly recursive datatypes such as
  4083 
  4084   datatype
  4085     ('a, 'b) term = Var 'a
  4086                   | App 'b ((('a, 'b) term) list)
  4087 
  4088 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4089 induction on mutually / indirectly recursive datatypes.
  4090 
  4091 Primrec equations are now stored in theory and can be accessed via
  4092 <function_name>.simps.
  4093 
  4094 INCOMPATIBILITIES:
  4095 
  4096   - Theories using datatypes must now have theory Datatype as an
  4097     ancestor.
  4098   - The specific <typename>.induct_tac no longer exists - use the
  4099     generic induct_tac instead.
  4100   - natE has been renamed to nat.exhaust - use exhaust_tac
  4101     instead of res_inst_tac ... natE. Note that the variable
  4102     names in nat.exhaust differ from the names in natE, this
  4103     may cause some "fragile" proofs to fail.
  4104   - The theorems split_<typename>_case and split_<typename>_case_asm
  4105     have been renamed to <typename>.split and <typename>.split_asm.
  4106   - Since default sorts of type variables are now handled correctly,
  4107     some datatype definitions may have to be annotated with explicit
  4108     sort constraints.
  4109   - Primrec definitions no longer require function name and type
  4110     of recursive argument.
  4111 
  4112 Consider using isatool fixdatatype to adapt your theories and proof
  4113 scripts to the new package (backup your sources first!).
  4114 
  4115 
  4116 * HOL/record package: considerably improved implementation; now
  4117 includes concrete syntax for record types, terms, updates; theorems
  4118 for surjective pairing and splitting !!-bound record variables; proof
  4119 support is as follows:
  4120 
  4121   1) standard conversions (selectors or updates applied to record
  4122 constructor terms) are part of the standard simpset;
  4123 
  4124   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4125 made part of standard simpset and claset via addIffs;
  4126 
  4127   3) a tactic for record field splitting (record_split_tac) is part of
  4128 the standard claset (addSWrapper);
  4129 
  4130 To get a better idea about these rules you may retrieve them via
  4131 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4132 the name of your record type.
  4133 
  4134 The split tactic 3) conceptually simplifies by the following rule:
  4135 
  4136   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4137 
  4138 Thus any record variable that is bound by meta-all will automatically
  4139 blow up into some record constructor term, consequently the
  4140 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4141 solve record problems automatically.
  4142 
  4143 
  4144 * reorganized the main HOL image: HOL/Integ and String loaded by
  4145 default; theory Main includes everything;
  4146 
  4147 * automatic simplification of integer sums and comparisons, using cancellation;
  4148 
  4149 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4150 
  4151 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4152 
  4153 * many new identities for unions, intersections, set difference, etc.;
  4154 
  4155 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4156 called split_if, split_split, split_sum_case and split_nat_case (to go
  4157 with add/delsplits);
  4158 
  4159 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4160 (?x::unit) = (); this is made part of the default simpset, which COULD
  4161 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4162 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4163 unit_abs_eta_conv is added in order to counter the effect of
  4164 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4165 %u.f();
  4166 
  4167 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4168 makes more sense);
  4169 
  4170 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4171   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4172   disjointness reasoning but breaking a few old proofs.
  4173 
  4174 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4175 to 'converse' from 'inverse' (for compatibility with ZF and some
  4176 literature);
  4177 
  4178 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4179 the well-founded relation;
  4180 
  4181 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4182     Compl A.  The "Compl" syntax remains available as input syntax for this
  4183     release ONLY.
  4184 
  4185 * HOL/Update: new theory of function updates:
  4186     f(a:=b) == %x. if x=a then b else f x
  4187 may also be iterated as in f(a:=b,c:=d,...);
  4188 
  4189 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4190 
  4191 * HOL/List:
  4192   - new function list_update written xs[i:=v] that updates the i-th
  4193     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4194   - new function `upt' written [i..j(] which generates the list
  4195     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4196     bound write [i..j], which is a shorthand for [i..j+1(].
  4197   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4198 
  4199 * HOL/Arith:
  4200   - removed 'pred' (predecessor) function;
  4201   - generalized some theorems about n-1;
  4202   - many new laws about "div" and "mod";
  4203   - new laws about greatest common divisors (see theory ex/Primes);
  4204 
  4205 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4206 instead of "inverse";
  4207 
  4208 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4209   of the multiset ordering;
  4210 
  4211 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4212   (not included by default);
  4213 
  4214 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4215 
  4216 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4217   programs, i.e. different program variables may have different types.
  4218 
  4219 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4220   [previously, this check worked only if the rewrite rule was unconditional]
  4221   Now rew can involve either definitions or equalities (either == or =).
  4222 
  4223 
  4224 *** ZF ***
  4225 
  4226 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4227   only the theorems proved on ZF.ML;
  4228 
  4229 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4230   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4231   disjointness reasoning but breaking a few old proofs.
  4232 
  4233 * ZF/Update: new theory of function updates
  4234     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4235   may also be iterated as in f(a:=b,c:=d,...);
  4236 
  4237 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4238 
  4239 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4240   [previously, this check worked only if the rewrite rule was unconditional]
  4241   Now rew can involve either definitions or equalities (either == or =).
  4242 
  4243 * case_tac provided for compatibility with HOL
  4244     (like the old excluded_middle_tac, but with subgoals swapped)
  4245 
  4246 
  4247 *** Internal programming interfaces ***
  4248 
  4249 * Pure: several new basic modules made available for general use, see
  4250 also src/Pure/README;
  4251 
  4252 * improved the theory data mechanism to support encapsulation (data
  4253 kind name replaced by private Object.kind, acting as authorization
  4254 key); new type-safe user interface via functor TheoryDataFun; generic
  4255 print_data function becomes basically useless;
  4256 
  4257 * removed global_names compatibility flag -- all theory declarations
  4258 are qualified by default;
  4259 
  4260 * module Pure/Syntax now offers quote / antiquote translation
  4261 functions (useful for Hoare logic etc. with implicit dependencies);
  4262 see HOL/ex/Antiquote for an example use;
  4263 
  4264 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4265 cterm -> thm;
  4266 
  4267 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4268 subgoal;
  4269 
  4270 * Display.print_goals function moved to Locale.print_goals;
  4271 
  4272 * standard print function for goals supports current_goals_markers
  4273 variable for marking begin of proof, end of proof, start of goal; the
  4274 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4275 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4276 for example;
  4277 
  4278 
  4279 
  4280 New in Isabelle98 (January 1998)
  4281 --------------------------------
  4282 
  4283 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4284 
  4285 * changed lexical syntax of terms / types: dots made part of long
  4286 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4287 
  4288 * simpset (and claset) reference variable replaced by functions
  4289 simpset / simpset_ref;
  4290 
  4291 * no longer supports theory aliases (via merge) and non-trivial
  4292 implicit merge of thms' signatures;
  4293 
  4294 * most internal names of constants changed due to qualified names;
  4295 
  4296 * changed Pure/Sequence interface (see Pure/seq.ML);
  4297 
  4298 
  4299 *** General Changes ***
  4300 
  4301 * hierachically structured name spaces (for consts, types, axms, thms
  4302 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4303 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4304 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4305 long_names for fully qualified output names; NOTE: ML programs
  4306 (special tactics, packages etc.) referring to internal names may have
  4307 to be adapted to cope with fully qualified names; in case of severe
  4308 backward campatibility problems try setting 'global_names' at compile
  4309 time to have enrything declared within a flat name space; one may also
  4310 fine tune name declarations in theories via the 'global' and 'local'
  4311 section;
  4312 
  4313 * reimplemented the implicit simpset and claset using the new anytype
  4314 data filed in signatures; references simpset:simpset ref etc. are
  4315 replaced by functions simpset:unit->simpset and
  4316 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4317 to patch your ML files accordingly;
  4318 
  4319 * HTML output now includes theory graph data for display with Java
  4320 applet or isatool browser; data generated automatically via isatool
  4321 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4322 
  4323 * defs may now be conditional; improved rewrite_goals_tac to handle
  4324 conditional equations;
  4325 
  4326 * defs now admits additional type arguments, using TYPE('a) syntax;
  4327 
  4328 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4329 creates a new theory node; implicit merge of thms' signatures is
  4330 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4331 transfer:theory->thm->thm in (rare) cases;
  4332 
  4333 * improved handling of draft signatures / theories; draft thms (and
  4334 ctyps, cterms) are automatically promoted to real ones;
  4335 
  4336 * slightly changed interfaces for oracles: admit many per theory, named
  4337 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4338 
  4339 * print_goals: optional output of const types (set show_consts and
  4340 show_types);
  4341 
  4342 * improved output of warnings (###) and errors (***);
  4343 
  4344 * subgoal_tac displays a warning if the new subgoal has type variables;
  4345 
  4346 * removed old README and Makefiles;
  4347 
  4348 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4349 
  4350 * removed obsolete init_pps and init_database;
  4351 
  4352 * deleted the obsolete tactical STATE, which was declared by
  4353     fun STATE tacfun st = tacfun st st;
  4354 
  4355 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4356 (which abbreviates $HOME);
  4357 
  4358 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4359 use isatool fixseq to adapt your ML programs (this works for fully
  4360 qualified references to the Sequence structure only!);
  4361 
  4362 * use_thy no longer requires writable current directory; it always
  4363 reloads .ML *and* .thy file, if either one is out of date;
  4364 
  4365 
  4366 *** Classical Reasoner ***
  4367 
  4368 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4369 tactics that use classical reasoning to simplify a subgoal without
  4370 splitting it into several subgoals;
  4371 
  4372 * Safe_tac: like safe_tac but uses the default claset;
  4373 
  4374 
  4375 *** Simplifier ***
  4376 
  4377 * added simplification meta rules:
  4378     (asm_)(full_)simplify: simpset -> thm -> thm;
  4379 
  4380 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4381 logics (again);
  4382 
  4383 * added prems argument to simplification procedures;
  4384 
  4385 * HOL, FOL, ZF: added infix function `addsplits':
  4386   instead of `<simpset> setloop (split_tac <thms>)'
  4387   you can simply write `<simpset> addsplits <thms>'
  4388 
  4389 
  4390 *** Syntax ***
  4391 
  4392 * TYPE('a) syntax for type reflection terms;
  4393 
  4394 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4395 
  4396 * pretty printer: changed order of mixfix annotation preference (again!);
  4397 
  4398 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4399 
  4400 
  4401 *** HOL ***
  4402 
  4403 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4404   with `addloop' of the simplifier to faciliate case splitting in premises.
  4405 
  4406 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4407 
  4408 * HOL/Auth: new protocol proofs including some for the Internet
  4409   protocol TLS;
  4410 
  4411 * HOL/Map: new theory of `maps' a la VDM;
  4412 
  4413 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4414 cancelling out common nat summands from =, <, <= (in)equalities, or
  4415 differences; simplification procedures nat_cancel_factor for
  4416 cancelling common factor from =, <, <= (in)equalities over natural
  4417 sums; nat_cancel contains both kinds of procedures, it is installed by
  4418 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4419 
  4420 * HOL/simplifier: terms of the form
  4421   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4422   are rewritten to
  4423   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4424   and those of the form
  4425   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4426   are rewritten to
  4427   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4428 
  4429 * HOL/datatype
  4430   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4431 
  4432   P(t_case f1 ... fn x) =
  4433      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4434         ...
  4435        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4436      )
  4437 
  4438   and a theorem `split_t_case_asm' of the form
  4439 
  4440   P(t_case f1 ... fn x) =
  4441     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4442         ...
  4443        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4444      )
  4445   which can be added to a simpset via `addsplits'. The existing theorems
  4446   expand_list_case and expand_option_case have been renamed to
  4447   split_list_case and split_option_case.
  4448 
  4449 * HOL/Arithmetic:
  4450   - `pred n' is automatically converted to `n-1'.
  4451     Users are strongly encouraged not to use `pred' any longer,
  4452     because it will disappear altogether at some point.
  4453   - Users are strongly encouraged to write "0 < n" rather than
  4454     "n ~= 0". Theorems and proof tools have been modified towards this
  4455     `standard'.
  4456 
  4457 * HOL/Lists:
  4458   the function "set_of_list" has been renamed "set" (and its theorems too);
  4459   the function "nth" now takes its arguments in the reverse order and
  4460   has acquired the infix notation "!" as in "xs!n".
  4461 
  4462 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4463 
  4464 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4465   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4466 
  4467 * HOL/record: extensible records with schematic structural subtyping
  4468 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4469 still lacks various theorems and concrete record syntax;
  4470 
  4471 
  4472 *** HOLCF ***
  4473 
  4474 * removed "axioms" and "generated by" sections;
  4475 
  4476 * replaced "ops" section by extended "consts" section, which is capable of
  4477   handling the continuous function space "->" directly;
  4478 
  4479 * domain package:
  4480   . proves theorems immediately and stores them in the theory,
  4481   . creates hierachical name space,
  4482   . now uses normal mixfix annotations (instead of cinfix...),
  4483   . minor changes to some names and values (for consistency),
  4484   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4485   . separator between mutual domain defs: changed "," to "and",
  4486   . improved handling of sort constraints;  now they have to
  4487     appear on the left-hand side of the equations only;
  4488 
  4489 * fixed LAM <x,y,zs>.b syntax;
  4490 
  4491 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4492 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4493 
  4494 
  4495 *** FOL and ZF ***
  4496 
  4497 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4498   with `addloop' of the simplifier to faciliate case splitting in premises.
  4499 
  4500 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4501 in HOL, they strip ALL and --> from proved theorems;
  4502 
  4503 
  4504 
  4505 New in Isabelle94-8 (May 1997)
  4506 ------------------------------
  4507 
  4508 *** General Changes ***
  4509 
  4510 * new utilities to build / run / maintain Isabelle etc. (in parts
  4511 still somewhat experimental); old Makefiles etc. still functional;
  4512 
  4513 * new 'Isabelle System Manual';
  4514 
  4515 * INSTALL text, together with ./configure and ./build scripts;
  4516 
  4517 * reimplemented type inference for greater efficiency, better error
  4518 messages and clean internal interface;
  4519 
  4520 * prlim command for dealing with lots of subgoals (an easier way of
  4521 setting goals_limit);
  4522 
  4523 
  4524 *** Syntax ***
  4525 
  4526 * supports alternative (named) syntax tables (parser and pretty
  4527 printer); internal interface is provided by add_modesyntax(_i);
  4528 
  4529 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4530 be used in conjunction with the Isabelle symbol font; uses the
  4531 "symbols" syntax table;
  4532 
  4533 * added token_translation interface (may translate name tokens in
  4534 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4535 the current print_mode); IMPORTANT: user print translation functions
  4536 are responsible for marking newly introduced bounds
  4537 (Syntax.mark_boundT);
  4538 
  4539 * token translations for modes "xterm" and "xterm_color" that display
  4540 names in bold, underline etc. or colors (which requires a color
  4541 version of xterm);
  4542 
  4543 * infixes may now be declared with names independent of their syntax;
  4544 
  4545 * added typed_print_translation (like print_translation, but may
  4546 access type of constant);
  4547 
  4548 
  4549 *** Classical Reasoner ***
  4550 
  4551 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4552 some limitations.  Blast_tac...
  4553   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4554   + ignores elimination rules that don't have the correct format
  4555         (the conclusion MUST be a formula variable)
  4556   + ignores types, which can make HOL proofs fail
  4557   + rules must not require higher-order unification, e.g. apply_type in ZF
  4558     [message "Function Var's argument not a bound variable" relates to this]
  4559   + its proof strategy is more general but can actually be slower
  4560 
  4561 * substitution with equality assumptions no longer permutes other
  4562 assumptions;
  4563 
  4564 * minor changes in semantics of addafter (now called addaltern); renamed
  4565 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4566 (and access functions for it);
  4567 
  4568 * improved combination of classical reasoner and simplifier:
  4569   + functions for handling clasimpsets
  4570   + improvement of addss: now the simplifier is called _after_ the
  4571     safe steps.
  4572   + safe variant of addss called addSss: uses safe simplifications
  4573     _during_ the safe steps. It is more complete as it allows multiple
  4574     instantiations of unknowns (e.g. with slow_tac).
  4575 
  4576 *** Simplifier ***
  4577 
  4578 * added interface for simplification procedures (functions that
  4579 produce *proven* rewrite rules on the fly, depending on current
  4580 redex);
  4581 
  4582 * ordering on terms as parameter (used for ordered rewriting);
  4583 
  4584 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4585 
  4586 * the solver is now split into a safe and an unsafe part.
  4587 This should be invisible for the normal user, except that the
  4588 functions setsolver and addsolver have been renamed to setSolver and
  4589 addSolver; added safe_asm_full_simp_tac;
  4590 
  4591 
  4592 *** HOL ***
  4593 
  4594 * a generic induction tactic `induct_tac' which works for all datatypes and
  4595 also for type `nat';
  4596 
  4597 * a generic case distinction tactic `exhaust_tac' which works for all
  4598 datatypes and also for type `nat';
  4599 
  4600 * each datatype comes with a function `size';
  4601 
  4602 * patterns in case expressions allow tuple patterns as arguments to
  4603 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4604 
  4605 * primrec now also works with type nat;
  4606 
  4607 * recdef: a new declaration form, allows general recursive functions to be
  4608 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4609 
  4610 * the constant for negation has been renamed from "not" to "Not" to
  4611 harmonize with FOL, ZF, LK, etc.;
  4612 
  4613 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4614 infinite lists;
  4615 
  4616 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4617 
  4618 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4619 problems in commutative rings, using axiomatic type classes for + and *;
  4620 
  4621 * more examples in HOL/MiniML and HOL/Auth;
  4622 
  4623 * more default rewrite rules for quantifiers, union/intersection;
  4624 
  4625 * a new constant `arbitrary == @x.False';
  4626 
  4627 * HOLCF/IOA replaces old HOL/IOA;
  4628 
  4629 * HOLCF changes: derived all rules and arities
  4630   + axiomatic type classes instead of classes
  4631   + typedef instead of faking type definitions
  4632   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4633   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4634   + eliminated the types void, one, tr
  4635   + use unit lift and bool lift (with translations) instead of one and tr
  4636   + eliminated blift from Lift3.thy (use Def instead of blift)
  4637   all eliminated rules are derived as theorems --> no visible changes ;
  4638 
  4639 
  4640 *** ZF ***
  4641 
  4642 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4643 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4644 as ZF_cs addSIs [equalityI];
  4645 
  4646 
  4647 
  4648 New in Isabelle94-7 (November 96)
  4649 ---------------------------------
  4650 
  4651 * allowing negative levels (as offsets) in prlev and choplev;
  4652 
  4653 * super-linear speedup for large simplifications;
  4654 
  4655 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4656 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4657 FAIL); can suppress it using the command Delsimps (ex_simps @
  4658 all_simps); De Morgan laws are also now included, by default;
  4659 
  4660 * improved printing of ==>  :  ~:
  4661 
  4662 * new object-logic "Sequents" adds linear logic, while replacing LK
  4663 and Modal (thanks to Sara Kalvala);
  4664 
  4665 * HOL/Auth: correctness proofs for authentication protocols;
  4666 
  4667 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4668 examples on HOL/Auth);
  4669 
  4670 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4671 the rewriter and classical reasoner simultaneously;
  4672 
  4673 * function uresult no longer returns theorems in "standard" format;
  4674 regain previous version by: val uresult = standard o uresult;
  4675 
  4676 
  4677 
  4678 New in Isabelle94-6
  4679 -------------------
  4680 
  4681 * oracles -- these establish an interface between Isabelle and trusted
  4682 external reasoners, which may deliver results as theorems;
  4683 
  4684 * proof objects (in particular record all uses of oracles);
  4685 
  4686 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4687 
  4688 * "constdefs" section in theory files;
  4689 
  4690 * "primrec" section (HOL) no longer requires names;
  4691 
  4692 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4693 
  4694 
  4695 
  4696 New in Isabelle94-5
  4697 -------------------
  4698 
  4699 * reduced space requirements;
  4700 
  4701 * automatic HTML generation from theories;
  4702 
  4703 * theory files no longer require "..." (quotes) around most types;
  4704 
  4705 * new examples, including two proofs of the Church-Rosser theorem;
  4706 
  4707 * non-curried (1994) version of HOL is no longer distributed;
  4708 
  4709 
  4710 
  4711 New in Isabelle94-4
  4712 -------------------
  4713 
  4714 * greatly reduced space requirements;
  4715 
  4716 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4717 
  4718 * searchable theorem database (see the section "Retrieving theorems" on
  4719 page 8 of the Reference Manual);
  4720 
  4721 * new examples, including Grabczewski's monumental case study of the
  4722 Axiom of Choice;
  4723 
  4724 * The previous version of HOL renamed to Old_HOL;
  4725 
  4726 * The new version of HOL (previously called CHOL) uses a curried syntax
  4727 for functions.  Application looks like f a b instead of f(a,b);
  4728 
  4729 * Mutually recursive inductive definitions finally work in HOL;
  4730 
  4731 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4732 translates to the operator "split";
  4733 
  4734 
  4735 
  4736 New in Isabelle94-3
  4737 -------------------
  4738 
  4739 * new infix operator, addss, allowing the classical reasoner to
  4740 perform simplification at each step of its search.  Example:
  4741         fast_tac (cs addss ss)
  4742 
  4743 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4744 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4745 look like (a,b) instead of <a,b>;
  4746 
  4747 * PLEASE NOTE: CHOL will eventually replace HOL!
  4748 
  4749 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4750 It translates to the operator "split".  A new theory of integers is available;
  4751 
  4752 * In ZF, integer numerals now denote two's-complement binary integers.
  4753 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4754 
  4755 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4756 of the Axiom of Choice;
  4757 
  4758 
  4759 
  4760 New in Isabelle94-2
  4761 -------------------
  4762 
  4763 * Significantly faster resolution;
  4764 
  4765 * the different sections in a .thy file can now be mixed and repeated
  4766 freely;
  4767 
  4768 * Database of theorems for FOL, HOL and ZF.  New
  4769 commands including qed, qed_goal and bind_thm store theorems in the database.
  4770 
  4771 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4772 a given theory (thms_of), or find out what theory a theorem was proved in
  4773 (theory_of_thm);
  4774 
  4775 * Bugs fixed in the inductive definition and datatype packages;
  4776 
  4777 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4778 and HOL_dup_cs obsolete;
  4779 
  4780 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4781 have been removed;
  4782 
  4783 * Simpler definition of function space in ZF;
  4784 
  4785 * new results about cardinal and ordinal arithmetic in ZF;
  4786 
  4787 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4788 types;
  4789 
  4790 
  4791 $Id$