NEWS
author wenzelm
Wed Jun 13 11:54:03 2007 +0200 (2007-06-13)
changeset 23369 227c51012cdb
parent 23367 05f399115ba5
child 23377 197b6a39592c
permissions -rw-r--r--
* Isar: method "assumption" (implicit closing of subproofs) takes non-atomic goal assumptions into account;
* Isar: implicit use of prems from the Isar proof context is considered a legacy feature;
     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). FUTURE INCOMPATIBILITY:
    12 legacy features will disappear eventually.
    13 
    14 * Theory syntax: the header format ``theory A = B + C:'' has been
    15 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    16 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: the old non-Isar theory file format has been
    19 discontinued altogether.  Note that ML proof scripts may still be used
    20 with Isar theories; migration is usually quite simple with the ML
    21 function use_legacy_bindings.  INCOMPATIBILITY.
    22 
    23 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    24 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    25 quotes.
    26 
    27 * Legacy goal package: reduced interface to the bare minimum required
    28 to keep existing proof scripts running.  Most other user-level
    29 functions are now part of the OldGoals structure, which is *not* open
    30 by default (consider isatool expandshort before open OldGoals).
    31 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    32 these tend to cause confusion about the actual goal (!) context being
    33 used here, which is not necessarily the same as the_context().
    34 
    35 * Command 'find_theorems': supports "*" wildcard in "name:" criterion.
    36 
    37 * Proof General interface: A search form for the "Find Theorems" command is
    38 now available via C-c C-a C-f.  The old minibuffer interface is available
    39 via C-c C-a C-m.  Variable proof-find-theorems-command (customizable via
    40 'Proof-General -> Advanced -> Internals -> Prover Config') controls the
    41 default behavior of 'ProofGeneral -> Find Theorems' (C-c C-f): set to
    42 isar-find-theorems-form or isar-find-theorems-minibuffer.
    43 
    44 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    45 by default, which means that "prems" (and also "fixed variables") are
    46 suppressed from proof state output.  Note that the ProofGeneral
    47 settings mechanism allows to change and save options persistently, but
    48 older versions of Isabelle will fail to start up if a negative prems
    49 limit is imposed.
    50 
    51 * Local theory targets may be specified by non-nested blocks of
    52 ``context/locale/class ... begin'' followed by ``end''.  The body may
    53 contain definitions, theorems etc., including any derived mechanism
    54 that has been implemented on top of these primitives.  This concept
    55 generalizes the existing ``theorem (in ...)'' towards more versatility
    56 and scalability.
    57 
    58 * Proof General interface: proper undo of final 'end' command;
    59 discontinued Isabelle/classic mode (ML proof scripts).
    60 
    61 
    62 *** Document preparation ***
    63 
    64 * Added antiquotation @{theory name} which prints the given name,
    65 after checking that it refers to a valid ancestor theory in the
    66 current context.
    67 
    68 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    69 check the given source text as ML type/structure, printing verbatim.
    70 
    71 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    72 "c args == rhs" given in the current context.  (Any number of
    73 arguments may be given on the LHS.)
    74 
    75 
    76 
    77 *** Pure ***
    78 
    79 * code generator: consts in 'consts_code' Isar commands are now referred
    80   to by usual term syntax (including optional type annotations).
    81 
    82 * code generator: 
    83   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    84     explicitly to the table of defining equations
    85   - primitive definitions are not used as defining equations by default any longer
    86   - defining equations are now definitly restricted to meta "==" and object
    87         equality "="
    88   - HOL theories have been adopted accordingly
    89 
    90 * class_package.ML offers a combination of axclasses and locales to
    91 achieve Haskell-like type classes in Isabelle.  See
    92 HOL/ex/Classpackage.thy for examples.
    93 
    94 * Yet another code generator framework allows to generate executable
    95 code for ML and Haskell (including "class"es).  A short usage sketch:
    96 
    97     internal compilation:
    98         code_gen <list of constants (term syntax)> (SML #)
    99     writing SML code to a file:
   100         code_gen <list of constants (term syntax)> (SML <filename>)
   101     writing OCaml code to a file:
   102         code_gen <list of constants (term syntax)> (OCaml <filename>)
   103     writing Haskell code to a bunch of files:
   104         code_gen <list of constants (term syntax)> (Haskell <filename>)
   105 
   106 Reasonable default setup of framework in HOL/Main.
   107 
   108 Theorem attributs for selecting and transforming function equations theorems:
   109 
   110     [code fun]:        select a theorem as function equation for a specific constant
   111     [code fun del]:    deselect a theorem as function equation for a specific constant
   112     [code inline]:     select an equation theorem for unfolding (inlining) in place
   113     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   114 
   115 User-defined serializations (target in {SML, OCaml, Haskell}):
   116 
   117     code_const <and-list of constants (term syntax)>
   118       {(target) <and-list of const target syntax>}+
   119 
   120     code_type <and-list of type constructors>
   121       {(target) <and-list of type target syntax>}+
   122 
   123     code_instance <and-list of instances>
   124       {(target)}+
   125         where instance ::= <type constructor> :: <class>
   126 
   127     code_class <and_list of classes>
   128       {(target) <and-list of class target syntax>}+
   129         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   130 
   131 code_instance and code_class only apply to target Haskell.
   132 
   133 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   134 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   135 
   136 * Command 'no_translations' removes translation rules from theory
   137 syntax.
   138 
   139 * Overloaded definitions are now actually checked for acyclic
   140 dependencies.  The overloading scheme is slightly more general than
   141 that of Haskell98, although Isabelle does not demand an exact
   142 correspondence to type class and instance declarations.
   143 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   144 exotic versions of overloading -- at the discretion of the user!
   145 
   146 Polymorphic constants are represented via type arguments, i.e. the
   147 instantiation that matches an instance against the most general
   148 declaration given in the signature.  For example, with the declaration
   149 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   150 as c(nat).  Overloading is essentially simultaneous structural
   151 recursion over such type arguments.  Incomplete specification patterns
   152 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   153 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   154 Command 'print_theory' outputs the normalized system of recursive
   155 equations, see section "definitions".
   156 
   157 * Isar: method "assumption" (and implicit closing of subproofs) now
   158 takes simple non-atomic goal assumptions into account: after applying
   159 an assumption as a rule the resulting subgoals are solved by atomic
   160 assumption steps.  This is particularly useful to finish 'obtain'
   161 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   162 without referring to the original premise "!!x. P x ==> thesis" in the
   163 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   164 more permissive.
   165 
   166 * Isar: implicit use of prems from the Isar proof context is
   167 considered a legacy feature.  Common applications like ``have A .''
   168 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   169 referencing facts explicitly here improves readability and
   170 maintainability of proof texts.
   171 
   172 * Isar: improper proof element 'guess' is like 'obtain', but derives
   173 the obtained context from the course of reasoning!  For example:
   174 
   175   assume "EX x y. A x & B y"   -- "any previous fact"
   176   then guess x and y by clarify
   177 
   178 This technique is potentially adventurous, depending on the facts and
   179 proof tools being involved here.
   180 
   181 * Isar: known facts from the proof context may be specified as literal
   182 propositions, using ASCII back-quote syntax.  This works wherever
   183 named facts used to be allowed so far, in proof commands, proof
   184 methods, attributes etc.  Literal facts are retrieved from the context
   185 according to unification of type and term parameters.  For example,
   186 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   187 theorems in the current context, then these are valid literal facts:
   188 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   189 
   190 There is also a proof method "fact" which does the same composition
   191 for explicit goal states, e.g. the following proof texts coincide with
   192 certain special cases of literal facts:
   193 
   194   have "A" by fact                 ==  note `A`
   195   have "A ==> B" by fact           ==  note `A ==> B`
   196   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   197   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   198 
   199 * Isar: ":" (colon) is no longer a symbolic identifier character in
   200 outer syntax.  Thus symbolic identifiers may be used without
   201 additional white space in declarations like this: ``assume *: A''.
   202 
   203 * Isar: 'print_facts' prints all local facts of the current context,
   204 both named and unnamed ones.
   205 
   206 * Isar: 'def' now admits simultaneous definitions, e.g.:
   207 
   208   def x == "t" and y == "u"
   209 
   210 * Isar: added command 'unfolding', which is structurally similar to
   211 'using', but affects both the goal state and facts by unfolding given
   212 rewrite rules.  Thus many occurrences of the 'unfold' method or
   213 'unfolded' attribute may be replaced by first-class proof text.
   214 
   215 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   216 and command 'unfolding' now all support object-level equalities
   217 (potentially conditional).  The underlying notion of rewrite rule is
   218 analogous to the 'rule_format' attribute, but *not* that of the
   219 Simplifier (which is usually more generous).
   220 
   221 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   222 method expression within a sandbox consisting of the first N
   223 sub-goals, which need to exist.  For example, ``simp_all [3]''
   224 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   225 simplifies all new goals that emerge from applying rule foo to the
   226 originally first one.
   227 
   228 * Isar: schematic goals are no longer restricted to higher-order
   229 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   230 expected.
   231 
   232 * Isar: the conclusion of a long theorem statement is now either
   233 'shows' (a simultaneous conjunction, as before), or 'obtains'
   234 (essentially a disjunction of cases with local parameters and
   235 assumptions).  The latter allows to express general elimination rules
   236 adequately; in this notation common elimination rules look like this:
   237 
   238   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   239     assumes "EX x. P x"
   240     obtains x where "P x"
   241 
   242   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   243     assumes "A & B"
   244     obtains A and B
   245 
   246   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   247     assumes "A | B"
   248     obtains
   249       A
   250     | B
   251 
   252 The subsequent classical rules even refer to the formal "thesis"
   253 explicitly:
   254 
   255   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   256     obtains "~ thesis"
   257 
   258   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   259     obtains "thesis ==> something"
   260 
   261 The actual proof of an 'obtains' statement is analogous to that of the
   262 Isar proof element 'obtain', only that there may be several cases.
   263 Optional case names may be specified in parentheses; these will be
   264 available both in the present proof and as annotations in the
   265 resulting rule, for later use with the 'cases' method (cf. attribute
   266 case_names).
   267 
   268 * Isar: the assumptions of a long theorem statement are available as
   269 "assms" fact in the proof context.  This is more appropriate than the
   270 (historical) "prems", which refers to all assumptions of the current
   271 context, including those from the target locale, proof body etc.
   272 
   273 * Isar: 'print_statement' prints theorems from the current theory or
   274 proof context in long statement form, according to the syntax of a
   275 top-level lemma.
   276 
   277 * Isar: 'obtain' takes an optional case name for the local context
   278 introduction rule (default "that").
   279 
   280 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   281 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   282 to occur.
   283 
   284 * Pure: syntax "CONST name" produces a fully internalized constant
   285 according to the current context.  This is particularly useful for
   286 syntax translations that should refer to internal constant
   287 representations independently of name spaces.
   288 
   289 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   290 instead of "FOO ". This allows multiple binder declarations to coexist
   291 in the same context.  INCOMPATIBILITY.
   292 
   293 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   294 primitive that also works in a locale context (both for constants and
   295 fixed variables).  Type declaration and internal syntactic
   296 representation of given constants retrieved from the context.
   297 
   298 * Isar/locales: new derived specification elements 'axiomatization',
   299 'definition', 'abbreviation', which support type-inference, admit
   300 object-level specifications (equality, equivalence).  See also the
   301 isar-ref manual.  Examples:
   302 
   303   axiomatization
   304     eq  (infix "===" 50) where
   305     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   306 
   307   definition "f x y = x + y + 1"
   308   definition g where "g x = f x x"
   309 
   310   abbreviation
   311     neq  (infix "=!=" 50) where
   312     "x =!= y == ~ (x === y)"
   313 
   314 These specifications may be also used in a locale context.  Then the
   315 constants being introduced depend on certain fixed parameters, and the
   316 constant name is qualified by the locale base name.  An internal
   317 abbreviation takes care for convenient input and output, making the
   318 parameters implicit and using the original short name.  See also
   319 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   320 entities from a monomorphic theory.
   321 
   322 Presently, abbreviations are only available 'in' a target locale, but
   323 not inherited by general import expressions.  Also note that
   324 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   325 'translations' in common applications.
   326 
   327 Concrete syntax is attached to specified constants in internal form,
   328 independently of name spaces.  The parse tree representation is
   329 slightly different -- use 'notation' instead of raw 'syntax', and
   330 'translations' with explicit "CONST" markup to accommodate this.
   331 
   332 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   333 the current context.  Print mode "no_abbrevs" prevents inversion of
   334 abbreviations on output.
   335 
   336 * Isar/locales: improved parameter handling:
   337 - use of locales "var" and "struct" no longer necessary;
   338 - parameter renamings are no longer required to be injective.
   339   This enables, for example, to define a locale for endomorphisms thus:
   340   locale endom = homom mult mult h.
   341 
   342 * Isar/locales: changed the way locales with predicates are defined.
   343 Instead of accumulating the specification, the imported expression is
   344 now an interpretation.  INCOMPATIBILITY: different normal form of
   345 locale expressions.  In particular, in interpretations of locales with
   346 predicates, goals repesenting already interpreted fragments are not
   347 removed automatically.  Use methods `intro_locales' and
   348 `unfold_locales'; see below.
   349 
   350 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   351 provide backward reasoning on locales predicates.  The methods are
   352 aware of interpretations and discharge corresponding goals.
   353 `intro_locales' is less aggressive then `unfold_locales' and does not
   354 unfold predicates to assumptions.
   355 
   356 * Isar/locales: the order in which locale fragments are accumulated
   357 has changed.  This enables to override declarations from fragments due
   358 to interpretations -- for example, unwanted simp rules.
   359 
   360 * Provers/induct: improved internal context management to support
   361 local fixes and defines on-the-fly.  Thus explicit meta-level
   362 connectives !! and ==> are rarely required anymore in inductive goals
   363 (using object-logic connectives for this purpose has been long
   364 obsolete anyway).  The subsequent proof patterns illustrate advanced
   365 techniques of natural induction; general datatypes and inductive sets
   366 work analogously (see also src/HOL/Lambda for realistic examples).
   367 
   368 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   369 parameters:
   370 
   371   lemma
   372     fixes n :: nat and x :: 'a
   373     assumes a: "A n x"
   374     shows "P n x"
   375     using a                     -- {* make induct insert fact a *}
   376   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   377     case 0
   378     show ?case sorry
   379   next
   380     case (Suc n)
   381     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   382     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   383     show ?case sorry
   384   qed
   385 
   386 (2) This is how to perform induction over ``expressions of a certain
   387 form'', using a locally defined inductive parameter n == "a x"
   388 together with strengthening (the latter is usually required to get
   389 sufficiently flexible induction hypotheses):
   390 
   391   lemma
   392     fixes a :: "'a => nat"
   393     assumes a: "A (a x)"
   394     shows "P (a x)"
   395     using a
   396   proof (induct n == "a x" arbitrary: x)
   397     ...
   398 
   399 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   400 particular technique.
   401 
   402 (3) This is how to perform existential reasoning ('obtains' or
   403 'obtain') by induction, while avoiding explicit object-logic
   404 encodings:
   405 
   406   lemma
   407     fixes n :: nat
   408     obtains x :: 'a where "P n x" and "Q n x"
   409   proof (induct n arbitrary: thesis)
   410     case 0
   411     obtain x where "P 0 x" and "Q 0 x" sorry
   412     then show thesis by (rule 0)
   413   next
   414     case (Suc n)
   415     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   416     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   417     then show thesis by (rule Suc.prems)
   418   qed
   419 
   420 Here the 'arbitrary: thesis' specification essentially modifies the
   421 scope of the formal thesis parameter, in order to the get the whole
   422 existence statement through the induction as expected.
   423 
   424 * Provers/induct: mutual induction rules are now specified as a list
   425 of rule sharing the same induction cases.  HOL packages usually
   426 provide foo_bar.inducts for mutually defined items foo and bar
   427 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   428 specify mutual induction rules differently, i.e. like this:
   429 
   430   (induct rule: foo_bar.inducts)
   431   (induct set: foo bar)
   432   (induct type: foo bar)
   433 
   434 The ML function ProjectRule.projections turns old-style rules into the
   435 new format.
   436 
   437 * Provers/induct: improved handling of simultaneous goals.  Instead of
   438 introducing object-level conjunction, the statement is now split into
   439 several conclusions, while the corresponding symbolic cases are
   440 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   441 explicitly.  For example:
   442 
   443   lemma
   444     fixes n :: nat
   445     shows "P n" and "Q n"
   446   proof (induct n)
   447     case 0 case 1
   448     show "P 0" sorry
   449   next
   450     case 0 case 2
   451     show "Q 0" sorry
   452   next
   453     case (Suc n) case 1
   454     note `P n` and `Q n`
   455     show "P (Suc n)" sorry
   456   next
   457     case (Suc n) case 2
   458     note `P n` and `Q n`
   459     show "Q (Suc n)" sorry
   460   qed
   461 
   462 The split into subcases may be deferred as follows -- this is
   463 particularly relevant for goal statements with local premises.
   464 
   465   lemma
   466     fixes n :: nat
   467     shows "A n ==> P n" and "B n ==> Q n"
   468   proof (induct n)
   469     case 0
   470     {
   471       case 1
   472       note `A 0`
   473       show "P 0" sorry
   474     next
   475       case 2
   476       note `B 0`
   477       show "Q 0" sorry
   478     }
   479   next
   480     case (Suc n)
   481     note `A n ==> P n` and `B n ==> Q n`
   482     {
   483       case 1
   484       note `A (Suc n)`
   485       show "P (Suc n)" sorry
   486     next
   487       case 2
   488       note `B (Suc n)`
   489       show "Q (Suc n)" sorry
   490     }
   491   qed
   492 
   493 If simultaneous goals are to be used with mutual rules, the statement
   494 needs to be structured carefully as a two-level conjunction, using
   495 lists of propositions separated by 'and':
   496 
   497   lemma
   498     shows "a : A ==> P1 a"
   499           "a : A ==> P2 a"
   500       and "b : B ==> Q1 b"
   501           "b : B ==> Q2 b"
   502           "b : B ==> Q3 b"
   503   proof (induct set: A B)
   504 
   505 * Provers/induct: support coinduction as well.  See
   506 src/HOL/Library/Coinductive_List.thy for various examples.
   507 
   508 * Attribute "symmetric" produces result with standardized schematic
   509 variables (index 0).  Potential INCOMPATIBILITY.
   510 
   511 * Simplifier: by default the simplifier trace only shows top level
   512 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   513 default. Thus there is less danger of being flooded by the trace. The
   514 trace indicates where parts have been suppressed.
   515   
   516 * Provers/classical: removed obsolete classical version of elim_format
   517 attribute; classical elim/dest rules are now treated uniformly when
   518 manipulating the claset.
   519 
   520 * Provers/classical: stricter checks to ensure that supplied intro,
   521 dest and elim rules are well-formed; dest and elim rules must have at
   522 least one premise.
   523 
   524 * Provers/classical: attributes dest/elim/intro take an optional
   525 weight argument for the rule (just as the Pure versions).  Weights are
   526 ignored by automated tools, but determine the search order of single
   527 rule steps.
   528 
   529 * Syntax: input syntax now supports dummy variable binding "%_. b",
   530 where the body does not mention the bound variable.  Note that dummy
   531 patterns implicitly depend on their context of bounds, which makes
   532 "{_. _}" match any set comprehension as expected.  Potential
   533 INCOMPATIBILITY -- parse translations need to cope with syntactic
   534 constant "_idtdummy" in the binding position.
   535 
   536 * Syntax: removed obsolete syntactic constant "_K" and its associated
   537 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   538 for example "A -> B" => "Pi A (%_. B)".
   539 
   540 * Pure: 'class_deps' command visualizes the subclass relation, using
   541 the graph browser tool.
   542 
   543 * Pure: 'print_theory' now suppresses entities with internal name
   544 (trailing "_") by default; use '!' option for full details.
   545 
   546 
   547 *** HOL ***
   548 
   549 * Method "algebra" solves polynomial equations over (semi)rings using
   550   Groebner bases. The (semi)ring structure is defined by locales and
   551   the tool setup depends on that generic context. Installing the
   552   method for a specific type involves instantiating the locale and
   553   possibly adding declarations for computation on the coefficients.
   554   The method is already instantiated for natural numbers and for the
   555   axiomatic class of idoms with numerals.  See also the paper by
   556   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   557   underlying this architecture of context-aware proof-tools.
   558 
   559 * constant "List.op @" now named "List.append".  Use ML antiquotations
   560 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   561 possible incompatibilities when working on ML level.
   562 
   563 * Constant renames due to introduction of canonical name prefixing for
   564   class package:
   565 
   566     HOL.abs ~> HOL.minus_class.abs
   567     HOL.divide ~> HOL.divide_class.divide
   568     Nat.power ~> Nat.power_class.power
   569     Nat.size ~> Nat.size_class.size
   570     Numeral.number_of ~> Numeral.number_class.number_of
   571     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   572 
   573 * Rudimentary class target mechanism involves constant renames:
   574 
   575     Orderings.min ~> Orderings.ord_class.min
   576     Orderings.max ~> Orderings.ord_class.max
   577     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   578 
   579 * case expressions and primrec: missing cases now mapped to "undefined"
   580 instead of "arbitrary"
   581 
   582 * new constant "undefined" with axiom "undefined x = undefined"
   583 
   584 * new class "default" with associated constant "default"
   585 
   586 * new function listsum :: 'a list => 'a for arbitrary monoids.
   587   Special syntax: "SUM x <- xs. f x" (and latex variants)
   588 
   589 * new (input only) syntax for Haskell-like list comprehension, eg
   590   [(x,y). x <- xs, y <- ys, x ~= y]
   591   For details see List.thy.
   592 
   593 * The special syntax for function "filter" has changed from [x : xs. P] to
   594   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   595   and for uniformity. INCOMPATIBILITY
   596 
   597 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   598     when generating code.
   599 
   600 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   601     when generating code.
   602 
   603 * Library/Commutative_Ring.thy: switched from recdef to function package;
   604     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   605 
   606 * Some steps towards more uniform lattice theory development in HOL.
   607 
   608     constants "meet" and "join" now named "inf" and "sup"
   609     constant "Meet" now named "Inf"
   610 
   611     classes "meet_semilorder" and "join_semilorder" now named
   612       "lower_semilattice" and "upper_semilattice"
   613     class "lorder" now named "lattice"
   614     class "comp_lat" now named "complete_lattice"
   615 
   616     Instantiation of lattice classes allows explicit definitions
   617     for "inf" and "sup" operations.
   618 
   619   INCOMPATIBILITY.  Theorem renames:
   620 
   621     meet_left_le            ~> inf_le1
   622     meet_right_le           ~> inf_le2
   623     join_left_le            ~> sup_ge1
   624     join_right_le           ~> sup_ge2
   625     meet_join_le            ~> inf_sup_ord
   626     le_meetI                ~> le_infI
   627     join_leI                ~> le_supI
   628     le_meet                 ~> le_inf_iff
   629     le_join                 ~> ge_sup_conv
   630     meet_idempotent         ~> inf_idem
   631     join_idempotent         ~> sup_idem
   632     meet_comm               ~> inf_commute
   633     join_comm               ~> sup_commute
   634     meet_leI1               ~> le_infI1
   635     meet_leI2               ~> le_infI2
   636     le_joinI1               ~> le_supI1
   637     le_joinI2               ~> le_supI2
   638     meet_assoc              ~> inf_assoc
   639     join_assoc              ~> sup_assoc
   640     meet_left_comm          ~> inf_left_commute
   641     meet_left_idempotent    ~> inf_left_idem
   642     join_left_comm          ~> sup_left_commute
   643     join_left_idempotent    ~> sup_left_idem
   644     meet_aci                ~> inf_aci
   645     join_aci                ~> sup_aci
   646     le_def_meet             ~> le_iff_inf
   647     le_def_join             ~> le_iff_sup
   648     join_absorp2            ~> sup_absorb2
   649     join_absorp1            ~> sup_absorb1
   650     meet_absorp1            ~> inf_absorb1
   651     meet_absorp2            ~> inf_absorb2
   652     meet_join_absorp        ~> inf_sup_absorb
   653     join_meet_absorp        ~> sup_inf_absorb
   654     distrib_join_le         ~> distrib_sup_le
   655     distrib_meet_le         ~> distrib_inf_le
   656 
   657     add_meet_distrib_left   ~> add_inf_distrib_left
   658     add_join_distrib_left   ~> add_sup_distrib_left
   659     is_join_neg_meet        ~> is_join_neg_inf
   660     is_meet_neg_join        ~> is_meet_neg_sup
   661     add_meet_distrib_right  ~> add_inf_distrib_right
   662     add_join_distrib_right  ~> add_sup_distrib_right
   663     add_meet_join_distribs  ~> add_sup_inf_distribs
   664     join_eq_neg_meet        ~> sup_eq_neg_inf
   665     meet_eq_neg_join        ~> inf_eq_neg_sup
   666     add_eq_meet_join        ~> add_eq_inf_sup
   667     meet_0_imp_0            ~> inf_0_imp_0
   668     join_0_imp_0            ~> sup_0_imp_0
   669     meet_0_eq_0             ~> inf_0_eq_0
   670     join_0_eq_0             ~> sup_0_eq_0
   671     neg_meet_eq_join        ~> neg_inf_eq_sup
   672     neg_join_eq_meet        ~> neg_sup_eq_inf
   673     join_eq_if              ~> sup_eq_if
   674 
   675     mono_meet               ~> mono_inf
   676     mono_join               ~> mono_sup
   677     meet_bool_eq            ~> inf_bool_eq
   678     join_bool_eq            ~> sup_bool_eq
   679     meet_fun_eq             ~> inf_fun_eq
   680     join_fun_eq             ~> sup_fun_eq
   681     meet_set_eq             ~> inf_set_eq
   682     join_set_eq             ~> sup_set_eq
   683     meet1_iff               ~> inf1_iff
   684     meet2_iff               ~> inf2_iff
   685     meet1I                  ~> inf1I
   686     meet2I                  ~> inf2I
   687     meet1D1                 ~> inf1D1
   688     meet2D1                 ~> inf2D1
   689     meet1D2                 ~> inf1D2
   690     meet2D2                 ~> inf2D2
   691     meet1E                  ~> inf1E
   692     meet2E                  ~> inf2E
   693     join1_iff               ~> sup1_iff
   694     join2_iff               ~> sup2_iff
   695     join1I1                 ~> sup1I1
   696     join2I1                 ~> sup2I1
   697     join1I1                 ~> sup1I1
   698     join2I2                 ~> sup1I2
   699     join1CI                 ~> sup1CI
   700     join2CI                 ~> sup2CI
   701     join1E                  ~> sup1E
   702     join2E                  ~> sup2E
   703 
   704     is_meet_Meet            ~> is_meet_Inf
   705     Meet_bool_def           ~> Inf_bool_def
   706     Meet_fun_def            ~> Inf_fun_def
   707     Meet_greatest           ~> Inf_greatest
   708     Meet_lower              ~> Inf_lower
   709     Meet_set_def            ~> Inf_set_def
   710 
   711     listsp_meetI            ~> listsp_infI
   712     listsp_meet_eq          ~> listsp_inf_eq
   713 
   714     meet_min                ~> inf_min
   715     join_max                ~> sup_max
   716 
   717 * Classes "order" and "linorder": facts "refl", "trans" and
   718 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   719 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   720 
   721 * Classes "order" and "linorder": 
   722 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   723 proofs changed.
   724 
   725 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   726 INCOMPATIBILITY.
   727 
   728 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   729 INCOMPATIBILITY.
   730 
   731 * Added syntactic class "size"; overloaded constant "size" now has
   732 type "'a::size ==> bool"
   733 
   734 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   735 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   736 
   737 * Added method "lexicographic_order" automatically synthesizes
   738 termination relations as lexicographic combinations of size measures
   739 -- 'function' package.
   740 
   741 * HOL/records: generalised field-update to take a function on the
   742 field rather than the new value: r(|A := x|) is translated to A_update
   743 (K x) r The K-combinator that is internally used is called K_record.
   744 INCOMPATIBILITY: Usage of the plain update functions has to be
   745 adapted.
   746  
   747 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   748 0 * x = 0, which are required for a semiring.  Richer structures do
   749 not inherit from semiring_0 anymore, because this property is a
   750 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   751 semiring_0, there is more to prove, but this is mostly trivial.
   752 
   753 * axclass "recpower" was generalized to arbitrary monoids, not just
   754 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   755 commutativity or a semiring property, add the corresponding classes.
   756 
   757 * Unified locale partial_order with class definition (cf. theory
   758 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   759 
   760 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   761 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   762 Isar level, use abbreviations instead.
   763 
   764 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   765 rarely occuring name references (e.g. ``List.op mem.simps'') require
   766 renaming (e.g. ``List.memberl.simps'').
   767 
   768 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   769 INCOMPATIBILITY.
   770 
   771 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   772 
   773 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   774 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   775 significant changes for setting up numeral syntax for types:
   776 
   777   - new constants Numeral.pred and Numeral.succ instead
   778       of former Numeral.bin_pred and Numeral.bin_succ.
   779   - Use integer operations instead of bin_add, bin_mult and so on.
   780   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   781   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   782 
   783 See HOL/Integ/IntArith.thy for an example setup.
   784 
   785 * New top level command 'normal_form' computes the normal form of a
   786 term that may contain free variables. For example ``normal_form
   787 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   788 suitable for heavy-duty computations because the functions are
   789 compiled to ML first.
   790 
   791 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   792 25 like -->); output depends on the "iff" print_mode, the default is
   793 "A = B" (with priority 50).
   794 
   795 * Renamed constants in HOL.thy and Orderings.thy:
   796     op +   ~> HOL.plus_class.plus
   797     op -   ~> HOL.minus_class.minus
   798     uminus ~> HOL.minus_class.uminus
   799     op *   ~> HOL.times_class.times
   800     op <   ~> Orderings.ord_class.less
   801     op <=  ~> Orderings.ord_class.less_eq
   802 
   803 Adaptions may be required in the following cases:
   804 
   805 a) User-defined constants using any of the names "plus", "minus", "times",
   806 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   807 may go wrong.
   808 INCOMPATIBILITY: use more specific names.
   809 
   810 b) Variables named "plus", "minus", "times", "less", "less_eq"
   811 INCOMPATIBILITY: use more specific names.
   812 
   813 c) Permutative equations (e.g. "a + b = b + a")
   814 Since the change of names also changes the order of terms, permutative
   815 rewrite rules may get applied in a different order. Experience shows that
   816 this is rarely the case (only two adaptions in the whole Isabelle
   817 distribution).
   818 INCOMPATIBILITY: rewrite proofs
   819 
   820 d) ML code directly refering to constant names
   821 This in general only affects hand-written proof tactics, simprocs and so on.
   822 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   823 of const_name ML antiquotations.
   824 
   825 * Relations less (<) and less_eq (<=) are also available on type bool.
   826 Modified syntax to disallow nesting without explicit parentheses,
   827 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   828 
   829 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   830 
   831 * Relation composition operator "op O" now has precedence 75 and binds
   832 stronger than union and intersection. INCOMPATIBILITY.
   833 
   834 * The old set interval syntax "{m..n(}" (and relatives) has been
   835 removed.  Use "{m..<n}" (and relatives) instead.
   836 
   837 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   838 "t = s" to False (by simproc "neq_simproc").  For backward
   839 compatibility this can be disabled by ML "reset use_neq_simproc".
   840 
   841 * "m dvd n" where m and n are numbers is evaluated to True/False by
   842 simp.
   843 
   844 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   845 
   846 * Theorem setsum_mult renamed to setsum_right_distrib.
   847 
   848 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   849 ``rule'' method.
   850 
   851 * Reimplemented methods ``sat'' and ``satx'', with several
   852 improvements: goals no longer need to be stated as "<prems> ==>
   853 False", equivalences (i.e. "=" on type bool) are handled, variable
   854 names of the form "lit_<n>" are no longer reserved, significant
   855 speedup.
   856 
   857 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   858 zChaff is still supported as well.
   859 
   860 * 'inductive' and 'datatype': provide projections of mutual rules,
   861 bundled as foo_bar.inducts;
   862 
   863 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   864 Library.
   865 
   866 * Library: moved theory Accessible_Part to main HOL.
   867 
   868 * Library: added theory Coinductive_List of potentially infinite lists
   869 as greatest fixed-point.
   870 
   871 * Library: added theory AssocList which implements (finite) maps as
   872 association lists.
   873 
   874 * Added proof method ``evaluation'' for efficiently solving a goal
   875 (i.e. a boolean expression) by compiling it to ML. The goal is
   876 "proved" (via an oracle) if it evaluates to True.
   877 
   878 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   879 also when invoked by the simplifier.  This results in the simplifier
   880 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   881 fast_arith_split_limit to 0 to obtain the old behavior.
   882 
   883 * Support for hex (0x20) and binary (0b1001) numerals.
   884 
   885 * New method: reify eqs (t), where eqs are equations for an
   886 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   887 parameter, computes a term s::'b and a list xs::'a list and proves the
   888 theorem I xs s = t. This is also known as reification or quoting. The
   889 resulting theorem is applied to the subgoal to substitute t with I xs
   890 s.  If t is omitted, the subgoal itself is reified.
   891 
   892 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   893 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   894 where f is supposed to be a computable function (in the sense of code
   895 generattion). The method uses reify to compute s and xs as above then
   896 applies corr_thm and uses normalization by evaluation to "prove" f s =
   897 r and finally gets the theorem t = r, which is again applied to the
   898 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   899 
   900 * Reflection: Automatic refification now handels binding, an example
   901 is available in HOL/ex/ReflectionEx.thy
   902 
   903 
   904 *** HOL-Algebra ***
   905 
   906 * Formalisation of ideals and the quotient construction over rings.
   907 
   908 * Order and lattice theory no longer based on records.
   909 INCOMPATIBILITY.
   910 
   911 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   912 greatest_closed.  INCOMPATIBILITY.
   913 
   914 * Method algebra is now set up via an attribute.  For examples see
   915 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   916 of algebraic structures.
   917 
   918 * Renamed theory CRing to Ring.
   919 
   920 
   921 *** HOL-Complex ***
   922 
   923 * Theory Real: new method ferrack implements quantifier elimination
   924 for linear arithmetic over the reals. The quantifier elimination
   925 feature is used only for decision, for compatibility with arith. This
   926 means a goal is either solved or left unchanged, no simplification.
   927 
   928 * Hyperreal: Functions root and sqrt are now defined on negative real
   929 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   930 Nonnegativity side conditions have been removed from many lemmas, so
   931 that more subgoals may now be solved by simplification; potential
   932 INCOMPATIBILITY.
   933 
   934 * Real: New axiomatic classes formalize real normed vector spaces and
   935 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   936 and norm :: 'a => real.
   937 
   938 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   939 from reals into other types. The overloaded constant Reals :: 'a set
   940 is now defined as range of_real; potential INCOMPATIBILITY.
   941 
   942 * Real: ML code generation is supported now and hence also quickcheck.
   943 Reals are implemented as arbitrary precision rationals.
   944 
   945 * Hyperreal: Several constants that previously worked only for the
   946 reals have been generalized, so they now work over arbitrary vector
   947 spaces. Type annotations may need to be added in some cases; potential
   948 INCOMPATIBILITY.
   949 
   950   Infinitesimal  :: ('a::real_normed_vector) star set
   951   HFinite        :: ('a::real_normed_vector) star set
   952   HInfinite      :: ('a::real_normed_vector) star set
   953   approx         :: ('a::real_normed_vector) star => 'a star => bool
   954   monad          :: ('a::real_normed_vector) star => 'a star set
   955   galaxy         :: ('a::real_normed_vector) star => 'a star set
   956   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   957   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   958   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   959   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   960   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   961   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   962   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   963   sgn            :: 'a::real_normed_vector => 'a
   964   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   965 
   966 * Complex: Some complex-specific constants are now abbreviations for
   967 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   968 hnorm.  Other constants have been entirely removed in favor of the
   969 polymorphic versions (INCOMPATIBILITY):
   970 
   971   approx        <-- capprox
   972   HFinite       <-- CFinite
   973   HInfinite     <-- CInfinite
   974   Infinitesimal <-- CInfinitesimal
   975   monad         <-- cmonad
   976   galaxy        <-- cgalaxy
   977   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   978   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   979   (ns)deriv     <-- (ns)cderiv
   980 
   981 
   982 *** ML ***
   983 
   984 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
   985 
   986 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   987 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   988 init only required for impure data.  INCOMPATIBILITY: empty really
   989 need to be empty (no dependencies on theory content!)
   990 
   991 * ML within Isar: antiquotations allow to embed statically-checked
   992 formal entities in the source, referring to the context available at
   993 compile-time.  For example:
   994 
   995 ML {* @{typ "'a => 'b"} *}
   996 ML {* @{term "%x. x"} *}
   997 ML {* @{prop "x == y"} *}
   998 ML {* @{ctyp "'a => 'b"} *}
   999 ML {* @{cterm "%x. x"} *}
  1000 ML {* @{cprop "x == y"} *}
  1001 ML {* @{thm asm_rl} *}
  1002 ML {* @{thms asm_rl} *}
  1003 ML {* @{const_name c} *}
  1004 ML {* @{const_syntax c} *}
  1005 ML {* @{context} *}
  1006 ML {* @{theory} *}
  1007 ML {* @{theory Pure} *}
  1008 ML {* @{simpset} *}
  1009 ML {* @{claset} *}
  1010 ML {* @{clasimpset} *}
  1011 
  1012 The same works for sources being ``used'' within an Isar context.
  1013 
  1014 * ML in Isar: improved error reporting; extra verbosity with
  1015 Toplevel.debug enabled.
  1016 
  1017 * Pure/library:
  1018 
  1019   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1020   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1021 
  1022 The semantics of "burrow" is: "take a function with *simulatanously*
  1023 transforms a list of value, and apply it *simulatanously* to a list of
  1024 list of values of the appropriate type". Compare this with "map" which
  1025 would *not* apply its argument function simulatanously but in
  1026 sequence; "fold_burrow" has an additional context.
  1027 
  1028 * Pure/library: functions map2 and fold2 with curried syntax for
  1029 simultanous mapping and folding:
  1030 
  1031     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1032     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1033 
  1034 * Pure/library: indexed lists - some functions in the Isabelle library
  1035 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1036 given more convenient names and signatures reminiscent of similar
  1037 functions for alists, tables, etc:
  1038 
  1039   val nth: 'a list -> int -> 'a 
  1040   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1041   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1042 
  1043 Note that fold_index starts counting at index 0, not 1 like foldln
  1044 used to.
  1045 
  1046 * Pure/library: added general ``divide_and_conquer'' combinator on
  1047 lists.
  1048 
  1049 * Pure/General/table.ML: the join operations now works via exceptions
  1050 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1051 admits slightly more efficient complex applications.
  1052 
  1053 * Pure: datatype Context.generic joins theory/Proof.context and
  1054 provides some facilities for code that works in either kind of
  1055 context, notably GenericDataFun for uniform theory and proof data.
  1056 
  1057 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1058 use Context.generic instead of just theory.
  1059 
  1060 * Pure: simplified internal attribute type, which is now always
  1061 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1062 vs. local (Proof.context) attributes have been discontinued, while
  1063 minimizing code duplication.  Thm.rule_attribute and
  1064 Thm.declaration_attribute build canonical attributes; see also
  1065 structure Context for further operations on Context.generic, notably
  1066 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1067 declarations and definitions.
  1068 
  1069 * Pure/kernel: consts certification ignores sort constraints given in
  1070 signature declarations.  (This information is not relevant to the
  1071 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1072 potential INCOMPATIBILITY.
  1073 
  1074 * Pure: axiomatic type classes are now purely definitional, with
  1075 explicit proofs of class axioms and super class relations performed
  1076 internally.  See Pure/axclass.ML for the main internal interfaces --
  1077 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1078 AxClass.axiomatize_class/classrel/arity supercede
  1079 Sign.add_classes/classrel/arities.
  1080 
  1081 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1082 global/local versions on theory vs. Proof.context have been
  1083 discontinued; Attrib.syntax and Method.syntax have been adapted
  1084 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1085 attributes, methods, etc.
  1086 
  1087 * Pure: several functions of signature "... -> theory -> theory * ..."
  1088 have been reoriented to "... -> theory -> ... * theory" in order to
  1089 allow natural usage in combination with the ||>, ||>>, |-> and
  1090 fold_map combinators.
  1091 
  1092 * Pure: official theorem names (closed derivations) and additional
  1093 comments (tags) are now strictly separate.  Name hints -- which are
  1094 maintained as tags -- may be attached any time without affecting the
  1095 derivation.
  1096 
  1097 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1098 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1099 achieve the old behaviour.
  1100 
  1101 * Pure: the "Goal" constant is now called "prop", supporting a
  1102 slightly more general idea of ``protecting'' meta-level rule
  1103 statements.
  1104 
  1105 * Pure: Logic.(un)varify only works in a global context, which is now
  1106 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1107 Logic.legacy_(un)varify as temporary workaround.
  1108 
  1109 * Pure: structure Name provides scalable operations for generating
  1110 internal variable names, notably Name.variants etc.  This replaces
  1111 some popular functions from term.ML:
  1112 
  1113   Term.variant		->  Name.variant
  1114   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1115   Term.invent_names	->  Name.invent_list
  1116 
  1117 Note that low-level renaming rarely occurs in new code -- operations
  1118 from structure Variable are used instead (see below).
  1119 
  1120 * Pure: structure Variable provides fundamental operations for proper
  1121 treatment of fixed/schematic variables in a context.  For example,
  1122 Variable.import introduces fixes for schematics of given facts and
  1123 Variable.export reverses the effect (up to renaming) -- this replaces
  1124 various freeze_thaw operations.
  1125 
  1126 * Pure: structure Goal provides simple interfaces for
  1127 init/conclude/finish and tactical prove operations (replacing former
  1128 Tactic.prove).  Goal.prove is the canonical way to prove results
  1129 within a given context; Goal.prove_global is a degraded version for
  1130 theory level goals, including a global Drule.standard.  Note that
  1131 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1132 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1133 in a locale context).
  1134 
  1135 * Isar: simplified treatment of user-level errors, using exception
  1136 ERROR of string uniformly.  Function error now merely raises ERROR,
  1137 without any side effect on output channels.  The Isar toplevel takes
  1138 care of proper display of ERROR exceptions.  ML code may use plain
  1139 handle/can/try; cat_error may be used to concatenate errors like this:
  1140 
  1141   ... handle ERROR msg => cat_error msg "..."
  1142 
  1143 Toplevel ML code (run directly or through the Isar toplevel) may be
  1144 embedded into the Isar toplevel with exception display/debug like
  1145 this:
  1146 
  1147   Isar.toplevel (fn () => ...)
  1148 
  1149 INCOMPATIBILITY, removed special transform_error facilities, removed
  1150 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1151 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1152 -- use plain ERROR instead.
  1153 
  1154 * Isar: theory setup now has type (theory -> theory), instead of a
  1155 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1156 
  1157 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1158 subject to ProofContext.debug/verbose flags.
  1159 
  1160 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1161 theory before entering a proof state.  Transactions now always see a
  1162 quasi-functional intermediate checkpoint, both in interactive and
  1163 batch mode.
  1164 
  1165 * Simplifier: the simpset of a running simplification process now
  1166 contains a proof context (cf. Simplifier.the_context), which is the
  1167 very context that the initial simpset has been retrieved from (by
  1168 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1169 (solver, looper etc.) may depend on arbitrary proof data.
  1170 
  1171 * Simplifier.inherit_context inherits the proof context (plus the
  1172 local bounds) of the current simplification process; any simproc
  1173 etc. that calls the Simplifier recursively should do this!  Removed
  1174 former Simplifier.inherit_bounds, which is already included here --
  1175 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1176 specify an explicit context using Simplifier.context/theory_context.
  1177 
  1178 * Simplifier/Classical Reasoner: more abstract interfaces
  1179 change_simpset/claset for modifying the simpset/claset reference of a
  1180 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1181 INCOMPATIBILITY.
  1182 
  1183 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1184 "Trueprop" etc.
  1185 
  1186 
  1187 *** System ***
  1188 
  1189 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1190 locations -- now includes the Isabelle version identifier as well.
  1191 This simplifies use of multiple Isabelle installations.
  1192 
  1193 * isabelle-process: option -S (secure mode) disables some critical
  1194 operations, notably runtime compilation and evaluation of ML source
  1195 code.
  1196 
  1197 
  1198 New in Isabelle2005 (October 2005)
  1199 ----------------------------------
  1200 
  1201 *** General ***
  1202 
  1203 * Theory headers: the new header syntax for Isar theories is
  1204 
  1205   theory <name>
  1206   imports <theory1> ... <theoryN>
  1207   uses <file1> ... <fileM>
  1208   begin
  1209 
  1210 where the 'uses' part is optional.  The previous syntax
  1211 
  1212   theory <name> = <theory1> + ... + <theoryN>:
  1213 
  1214 will disappear in the next release.  Use isatool fixheaders to convert
  1215 existing theory files.  Note that there is no change in ancient
  1216 non-Isar theories now, but these will disappear soon.
  1217 
  1218 * Theory loader: parent theories can now also be referred to via
  1219 relative and absolute paths.
  1220 
  1221 * Command 'find_theorems' searches for a list of criteria instead of a
  1222 list of constants. Known criteria are: intro, elim, dest, name:string,
  1223 simp:term, and any term. Criteria can be preceded by '-' to select
  1224 theorems that do not match. Intro, elim, dest select theorems that
  1225 match the current goal, name:s selects theorems whose fully qualified
  1226 name contain s, and simp:term selects all simplification rules whose
  1227 lhs match term.  Any other term is interpreted as pattern and selects
  1228 all theorems matching the pattern. Available in ProofGeneral under
  1229 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1230 
  1231   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1232 
  1233 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1234 matching the current goal as introduction rule and not having "HOL."
  1235 in their name (i.e. not being defined in theory HOL).
  1236 
  1237 * Command 'thms_containing' has been discontinued in favour of
  1238 'find_theorems'; INCOMPATIBILITY.
  1239 
  1240 * Communication with Proof General is now 8bit clean, which means that
  1241 Unicode text in UTF-8 encoding may be used within theory texts (both
  1242 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1243 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1244 
  1245   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1246   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1247 
  1248 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1249 Classical Reasoner.  Typical big applications run around 2 times
  1250 faster.
  1251 
  1252 
  1253 *** Document preparation ***
  1254 
  1255 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1256 of raw sources.  Only those symbols that do not require additional
  1257 LaTeX packages (depending on comments in isabellesym.sty) are
  1258 displayed properly, everything else is left verbatim.  isatool display
  1259 and isatool print are used as front ends (these are subject to the
  1260 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1261 
  1262 * Command tags control specific markup of certain regions of text,
  1263 notably folding and hiding.  Predefined tags include "theory" (for
  1264 theory begin and end), "proof" for proof commands, and "ML" for
  1265 commands involving ML code; the additional tags "visible" and
  1266 "invisible" are unused by default.  Users may give explicit tag
  1267 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1268 interpretation of tags is determined by the LaTeX job during document
  1269 preparation: see option -V of isatool usedir, or options -n and -t of
  1270 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1271 \isadroptag.
  1272 
  1273 Several document versions may be produced at the same time via isatool
  1274 usedir (the generated index.html will link all of them).  Typical
  1275 specifications include ''-V document=theory,proof,ML'' to present
  1276 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1277 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1278 these parts without any formal replacement text.  The Isabelle site
  1279 default settings produce ''document'' and ''outline'' versions as
  1280 specified above.
  1281 
  1282 * Several new antiquotations:
  1283 
  1284   @{term_type term} prints a term with its type annotated;
  1285 
  1286   @{typeof term} prints the type of a term;
  1287 
  1288   @{const const} is the same as @{term const}, but checks that the
  1289   argument is a known logical constant;
  1290 
  1291   @{term_style style term} and @{thm_style style thm} print a term or
  1292   theorem applying a "style" to it
  1293 
  1294   @{ML text}
  1295 
  1296 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1297 definitions, equations, inequations etc., 'concl' printing only the
  1298 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1299 to print the specified premise.  TermStyle.add_style provides an ML
  1300 interface for introducing further styles.  See also the "LaTeX Sugar"
  1301 document practical applications.  The ML antiquotation prints
  1302 type-checked ML expressions verbatim.
  1303 
  1304 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1305 and 'text' support optional locale specification '(in loc)', which
  1306 specifies the default context for interpreting antiquotations.  For
  1307 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1308 
  1309 * Option 'locale=NAME' of antiquotations specifies an alternative
  1310 context interpreting the subsequent argument.  For example: @{thm
  1311 [locale=lattice] inf_assoc}.
  1312 
  1313 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1314 a proof context.
  1315 
  1316 * Proper output of antiquotations for theory commands involving a
  1317 proof context (such as 'locale' or 'theorem (in loc) ...').
  1318 
  1319 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1320 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1321 
  1322 * isatool usedir: new option -C (default true) controls whether option
  1323 -D should include a copy of the original document directory; -C false
  1324 prevents unwanted effects such as copying of administrative CVS data.
  1325 
  1326 
  1327 *** Pure ***
  1328 
  1329 * Considerably improved version of 'constdefs' command.  Now performs
  1330 automatic type-inference of declared constants; additional support for
  1331 local structure declarations (cf. locales and HOL records), see also
  1332 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1333 sequential dependencies of definitions within a single 'constdefs'
  1334 section; moreover, the declared name needs to be an identifier.  If
  1335 all fails, consider to fall back on 'consts' and 'defs' separately.
  1336 
  1337 * Improved indexed syntax and implicit structures.  First of all,
  1338 indexed syntax provides a notational device for subscripted
  1339 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1340 expressions.  Secondly, in a local context with structure
  1341 declarations, number indexes \<^sub>n or the empty index (default
  1342 number 1) refer to a certain fixed variable implicitly; option
  1343 show_structs controls printing of implicit structures.  Typical
  1344 applications of these concepts involve record types and locales.
  1345 
  1346 * New command 'no_syntax' removes grammar declarations (and
  1347 translations) resulting from the given syntax specification, which is
  1348 interpreted in the same manner as for the 'syntax' command.
  1349 
  1350 * 'Advanced' translation functions (parse_translation etc.) may depend
  1351 on the signature of the theory context being presently used for
  1352 parsing/printing, see also isar-ref manual.
  1353 
  1354 * Improved 'oracle' command provides a type-safe interface to turn an
  1355 ML expression of type theory -> T -> term into a primitive rule of
  1356 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1357 is already included here); see also FOL/ex/IffExample.thy;
  1358 INCOMPATIBILITY.
  1359 
  1360 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1361 before); "cI" is no longer bound, use "c.intro" instead.
  1362 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1363 axclasses vs. locales.
  1364 
  1365 * Improved internal renaming of symbolic identifiers -- attach primes
  1366 instead of base 26 numbers.
  1367 
  1368 * New flag show_question_marks controls printing of leading question
  1369 marks in schematic variable names.
  1370 
  1371 * In schematic variable names, *any* symbol following \<^isub> or
  1372 \<^isup> is now treated as part of the base name.  For example, the
  1373 following works without printing of awkward ".0" indexes:
  1374 
  1375   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1376     by simp
  1377 
  1378 * Inner syntax includes (*(*nested*) comments*).
  1379 
  1380 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1381 annotations as "(00...)".
  1382 
  1383 * Clear separation of logical types and nonterminals, where the latter
  1384 may only occur in 'syntax' specifications or type abbreviations.
  1385 Before that distinction was only partially implemented via type class
  1386 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1387 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1388 exotic syntax specifications may require further adaption
  1389 (e.g. Cube/Cube.thy).
  1390 
  1391 * Removed obsolete type class "logic", use the top sort {} instead.
  1392 Note that non-logical types should be declared as 'nonterminals'
  1393 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1394 specifications.
  1395 
  1396 * Attributes 'induct' and 'cases': type or set names may now be
  1397 locally fixed variables as well.
  1398 
  1399 * Simplifier: can now control the depth to which conditional rewriting
  1400 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1401 Limit.
  1402 
  1403 * Simplifier: simplification procedures may now take the current
  1404 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1405 interface), which is very useful for calling the Simplifier
  1406 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1407 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1408 low-level mk_simproc no longer applies Logic.varify internally, to
  1409 allow for use in a context of fixed variables.
  1410 
  1411 * thin_tac now works even if the assumption being deleted contains !!
  1412 or ==>.  More generally, erule now works even if the major premise of
  1413 the elimination rule contains !! or ==>.
  1414 
  1415 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1416 
  1417 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1418 from Pure, which contains all common declarations already.  Both
  1419 theories are defined via plain Isabelle/Isar .thy files.
  1420 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1421 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1422 use isatool fixcpure to adapt your theory and ML sources.
  1423 
  1424 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1425 selections of theorems in named facts via index ranges.
  1426 
  1427 * 'print_theorems': in theory mode, really print the difference
  1428 wrt. the last state (works for interactive theory development only),
  1429 in proof mode print all local facts (cf. 'print_facts');
  1430 
  1431 * 'hide': option '(open)' hides only base names.
  1432 
  1433 * More efficient treatment of intermediate checkpoints in interactive
  1434 theory development.
  1435 
  1436 * Code generator is now invoked via code_module (incremental code
  1437 generation) and code_library (modular code generation, ML structures
  1438 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1439 must be quoted when used as identifiers.
  1440 
  1441 * New 'value' command for reading, evaluating and printing terms using
  1442 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1443 quoted when used as identifier.
  1444 
  1445 
  1446 *** Locales ***
  1447 
  1448 * New commands for the interpretation of locale expressions in
  1449 theories (1), locales (2) and proof contexts (3).  These generate
  1450 proof obligations from the expression specification.  After the
  1451 obligations have been discharged, theorems of the expression are added
  1452 to the theory, target locale or proof context.  The synopsis of the
  1453 commands is a follows:
  1454 
  1455   (1) interpretation expr inst
  1456   (2) interpretation target < expr
  1457   (3) interpret expr inst
  1458 
  1459 Interpretation in theories and proof contexts require a parameter
  1460 instantiation of terms from the current context.  This is applied to
  1461 specifications and theorems of the interpreted expression.
  1462 Interpretation in locales only permits parameter renaming through the
  1463 locale expression.  Interpretation is smart in that interpretations
  1464 that are active already do not occur in proof obligations, neither are
  1465 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1466 inspect active interpretations of a particular locale.  For details,
  1467 see the Isar Reference manual.  Examples can be found in
  1468 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1469 
  1470 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1471 'interpret' instead.
  1472 
  1473 * New context element 'constrains' for adding type constraints to
  1474 parameters.
  1475 
  1476 * Context expressions: renaming of parameters with syntax
  1477 redeclaration.
  1478 
  1479 * Locale declaration: 'includes' disallowed.
  1480 
  1481 * Proper static binding of attribute syntax -- i.e. types / terms /
  1482 facts mentioned as arguments are always those of the locale definition
  1483 context, independently of the context of later invocations.  Moreover,
  1484 locale operations (renaming and type / term instantiation) are applied
  1485 to attribute arguments as expected.
  1486 
  1487 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1488 actual attributes; rare situations may require Attrib.attribute to
  1489 embed those attributes into Attrib.src that lack concrete syntax.
  1490 Attribute implementations need to cooperate properly with the static
  1491 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1492 Attrib.XXX_thm etc. already do the right thing without further
  1493 intervention.  Only unusual applications -- such as "where" or "of"
  1494 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1495 on the context and the facts involved -- may have to assign parsed
  1496 values to argument tokens explicitly.
  1497 
  1498 * Changed parameter management in theorem generation for long goal
  1499 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1500 theorem statement in rare situations.
  1501 
  1502 * Locale inspection command 'print_locale' omits notes elements.  Use
  1503 'print_locale!' to have them included in the output.
  1504 
  1505 
  1506 *** Provers ***
  1507 
  1508 * Provers/hypsubst.ML: improved version of the subst method, for
  1509 single-step rewriting: it now works in bound variable contexts. New is
  1510 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1511 rewrite a different subterm than the original subst method, which is
  1512 still available as 'simplesubst'.
  1513 
  1514 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1515 and quasi orders.
  1516 
  1517 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1518 reflexive-transitive closure of relations.
  1519 
  1520 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1521 limit (previously hard-coded with a value of 20) user-definable.
  1522 
  1523 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1524 is peformed already.  Object-logics merely need to finish their
  1525 initial simpset configuration as before.  INCOMPATIBILITY.
  1526 
  1527 
  1528 *** HOL ***
  1529 
  1530 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1531 
  1532   syntax (epsilon)
  1533     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1534 
  1535 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1536 and x-symbol; use option '-m epsilon' to get it actually printed.
  1537 Moreover, the mathematically important symbolic identifier \<epsilon>
  1538 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1539 
  1540 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1541 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1542 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1543 support corresponding Isar calculations.
  1544 
  1545 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1546 instead of ":".
  1547 
  1548 * theory SetInterval: changed the syntax for open intervals:
  1549 
  1550   Old       New
  1551   {..n(}    {..<n}
  1552   {)n..}    {n<..}
  1553   {m..n(}   {m..<n}
  1554   {)m..n}   {m<..n}
  1555   {)m..n(}  {m<..<n}
  1556 
  1557 The old syntax is still supported but will disappear in the next
  1558 release.  For conversion use the following Emacs search and replace
  1559 patterns (these are not perfect but work quite well):
  1560 
  1561   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1562   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1563 
  1564 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1565 equalities in commutative rings; method 'algebra' provides a generic
  1566 interface.
  1567 
  1568 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1569 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1570 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1571 be a tuple pattern.
  1572 
  1573 Some new syntax forms are available:
  1574 
  1575   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1576   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1577   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1578   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1579 
  1580 The latter form "\<Sum>x < k. e" used to be based on a separate
  1581 function "Summation", which has been discontinued.
  1582 
  1583 * theory Finite_Set: in structured induction proofs, the insert case
  1584 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1585 (insert F x)'.
  1586 
  1587 * The 'refute' command has been extended to support a much larger
  1588 fragment of HOL, including axiomatic type classes, constdefs and
  1589 typedefs, inductive datatypes and recursion.
  1590 
  1591 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1592 Requires zChaff with proof generation to be installed.  See
  1593 HOL/ex/SAT_Examples.thy for examples.
  1594 
  1595 * Datatype induction via method 'induct' now preserves the name of the
  1596 induction variable. For example, when proving P(xs::'a list) by
  1597 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1598 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1599 in unstructured proof scripts.
  1600 
  1601 * Reworked implementation of records.  Improved scalability for
  1602 records with many fields, avoiding performance problems for type
  1603 inference. Records are no longer composed of nested field types, but
  1604 of nested extension types. Therefore the record type only grows linear
  1605 in the number of extensions and not in the number of fields.  The
  1606 top-level (users) view on records is preserved.  Potential
  1607 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1608 old record representation. The type generated for a record is called
  1609 <record_name>_ext_type.
  1610 
  1611 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1612 proofs triggered by a record definition or a simproc (if
  1613 quick_and_dirty is enabled).  Definitions of large records can take
  1614 quite long.
  1615 
  1616 New simproc record_upd_simproc for simplification of multiple record
  1617 updates enabled by default.  Moreover, trivial updates are also
  1618 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1619 occasionally, since simplification is more powerful by default.
  1620 
  1621 * typedef: proper support for polymorphic sets, which contain extra
  1622 type-variables in the term.
  1623 
  1624 * Simplifier: automatically reasons about transitivity chains
  1625 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1626 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1627 old proofs break occasionally as simplification may now solve more
  1628 goals than previously.
  1629 
  1630 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1631 present.  Works for all partial orders (class "order"), in particular
  1632 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1633 just like y <= x.
  1634 
  1635 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1636 bound variable or a constant then the let is unfolded.  Otherwise
  1637 first a is simplified to b, and then f b is simplified to g. If
  1638 possible we abstract b from g arriving at "let x = b in h x",
  1639 otherwise we unfold the let and arrive at g.  The simproc can be
  1640 enabled/disabled by the reference use_let_simproc.  Potential
  1641 INCOMPATIBILITY since simplification is more powerful by default.
  1642 
  1643 * Classical reasoning: the meson method now accepts theorems as arguments.
  1644 
  1645 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1646 jobs to provide advice on the provability of subgoals.
  1647 
  1648 * Theory OrderedGroup and Ring_and_Field: various additions and
  1649 improvements to faciliate calculations involving equalities and
  1650 inequalities.
  1651 
  1652 The following theorems have been eliminated or modified
  1653 (INCOMPATIBILITY):
  1654 
  1655   abs_eq             now named abs_of_nonneg
  1656   abs_of_ge_0        now named abs_of_nonneg
  1657   abs_minus_eq       now named abs_of_nonpos
  1658   imp_abs_id         now named abs_of_nonneg
  1659   imp_abs_neg_id     now named abs_of_nonpos
  1660   mult_pos           now named mult_pos_pos
  1661   mult_pos_le        now named mult_nonneg_nonneg
  1662   mult_pos_neg_le    now named mult_nonneg_nonpos
  1663   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1664   mult_neg           now named mult_neg_neg
  1665   mult_neg_le        now named mult_nonpos_nonpos
  1666 
  1667 * Theory Parity: added rules for simplifying exponents.
  1668 
  1669 * Theory List:
  1670 
  1671 The following theorems have been eliminated or modified
  1672 (INCOMPATIBILITY):
  1673 
  1674   list_all_Nil       now named list_all.simps(1)
  1675   list_all_Cons      now named list_all.simps(2)
  1676   list_all_conv      now named list_all_iff
  1677   set_mem_eq         now named mem_iff
  1678 
  1679 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1680 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1681 
  1682 
  1683 *** HOL-Complex ***
  1684 
  1685 * Theory RealDef: better support for embedding natural numbers and
  1686 integers in the reals.
  1687 
  1688 The following theorems have been eliminated or modified
  1689 (INCOMPATIBILITY):
  1690 
  1691   exp_ge_add_one_self  now requires no hypotheses
  1692   real_of_int_add      reversed direction of equality (use [symmetric])
  1693   real_of_int_minus    reversed direction of equality (use [symmetric])
  1694   real_of_int_diff     reversed direction of equality (use [symmetric])
  1695   real_of_int_mult     reversed direction of equality (use [symmetric])
  1696 
  1697 * Theory RComplete: expanded support for floor and ceiling functions.
  1698 
  1699 * Theory Ln is new, with properties of the natural logarithm
  1700 
  1701 * Hyperreal: There is a new type constructor "star" for making
  1702 nonstandard types.  The old type names are now type synonyms:
  1703 
  1704   hypreal = real star
  1705   hypnat = nat star
  1706   hcomplex = complex star
  1707 
  1708 * Hyperreal: Many groups of similarly-defined constants have been
  1709 replaced by polymorphic versions (INCOMPATIBILITY):
  1710 
  1711   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1712 
  1713   starset      <-- starsetNat, starsetC
  1714   *s*          <-- *sNat*, *sc*
  1715   starset_n    <-- starsetNat_n, starsetC_n
  1716   *sn*         <-- *sNatn*, *scn*
  1717   InternalSets <-- InternalNatSets, InternalCSets
  1718 
  1719   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1720   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1721   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1722   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1723   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1724 
  1725 * Hyperreal: Many type-specific theorems have been removed in favor of
  1726 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1727 
  1728   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1729   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1730   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1731   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1732   right_minus <-- hypreal_add_minus
  1733   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1734   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1735   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1736   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1737   mult_1_right <-- hcomplex_mult_one_right
  1738   mult_zero_left <-- hcomplex_mult_zero_left
  1739   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1740   right_distrib <-- hypnat_add_mult_distrib2
  1741   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1742   right_inverse <-- hypreal_mult_inverse
  1743   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1744   order_refl <-- {hypreal,hypnat}_le_refl
  1745   order_trans <-- {hypreal,hypnat}_le_trans
  1746   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1747   order_less_le <-- {hypreal,hypnat}_less_le
  1748   linorder_linear <-- {hypreal,hypnat}_le_linear
  1749   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1750   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1751   add_nonneg_nonneg <-- hypreal_le_add_order
  1752 
  1753 * Hyperreal: Separate theorems having to do with type-specific
  1754 versions of constants have been merged into theorems that apply to the
  1755 new polymorphic constants (INCOMPATIBILITY):
  1756 
  1757   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1758   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1759   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1760   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1761   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1762   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1763   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1764   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1765   STAR_diff <-- {STAR,STARC}_diff
  1766   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1767     STARC_hcomplex_of_complex}_image_subset
  1768   starset_n_Un <-- starset{Nat,C}_n_Un
  1769   starset_n_Int <-- starset{Nat,C}_n_Int
  1770   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1771   starset_n_diff <-- starset{Nat,C}_n_diff
  1772   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1773   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1774   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1775   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1776   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1777   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1778   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1779   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1780   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1781   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1782   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1783   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1784   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1785   starfun_diff <-- starfun{C,RC,CR}_diff
  1786   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1787   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1788   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1789   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1790   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1791   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1792   starfun_Id <-- starfunC_Id
  1793   starfun_approx <-- starfun{Nat,CR}_approx
  1794   starfun_capprox <-- starfun{C,RC}_capprox
  1795   starfun_abs <-- starfunNat_rabs
  1796   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1797   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1798   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1799   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1800   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1801   starfun_add_approx <-- starfunCR_add_approx
  1802   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1803   starfun_divide <-- starfun{C,CR,RC}_divide
  1804   starfun_n <-- starfun{Nat,C}_n
  1805   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1806   starfun_n_add <-- starfun{Nat,C}_n_add
  1807   starfun_n_add_minus <-- starfunNat_n_add_minus
  1808   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1809   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1810   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1811 
  1812   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1813   star_n_minus <-- {hypreal,hcomplex}_minus
  1814   star_n_diff <-- {hypreal,hcomplex}_diff
  1815   star_n_mult <-- {hypreal,hcomplex}_mult
  1816   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1817   star_n_le <-- {hypreal,hypnat}_le
  1818   star_n_less <-- {hypreal,hypnat}_less
  1819   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1820   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1821   star_n_abs <-- hypreal_hrabs
  1822   star_n_divide <-- hcomplex_divide
  1823 
  1824   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1825   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1826   star_of_diff <-- hypreal_of_real_diff
  1827   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1828   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1829   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1830   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1831   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1832   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1833   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1834   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1835   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1836   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1837   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1838   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1839   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1840   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1841   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1842   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1843   star_of_power <-- hypreal_of_real_power
  1844   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1845 
  1846 * Hyperreal: new method "transfer" that implements the transfer
  1847 principle of nonstandard analysis. With a subgoal that mentions
  1848 nonstandard types like "'a star", the command "apply transfer"
  1849 replaces it with an equivalent one that mentions only standard types.
  1850 To be successful, all free variables must have standard types; non-
  1851 standard variables must have explicit universal quantifiers.
  1852 
  1853 * Hyperreal: A theory of Taylor series.
  1854 
  1855 
  1856 *** HOLCF ***
  1857 
  1858 * Discontinued special version of 'constdefs' (which used to support
  1859 continuous functions) in favor of the general Pure one with full
  1860 type-inference.
  1861 
  1862 * New simplification procedure for solving continuity conditions; it
  1863 is much faster on terms with many nested lambda abstractions (cubic
  1864 instead of exponential time).
  1865 
  1866 * New syntax for domain package: selector names are now optional.
  1867 Parentheses should be omitted unless argument is lazy, for example:
  1868 
  1869   domain 'a stream = cons "'a" (lazy "'a stream")
  1870 
  1871 * New command 'fixrec' for defining recursive functions with pattern
  1872 matching; defining multiple functions with mutual recursion is also
  1873 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1874 sinr, or any data constructor defined by the domain package. The given
  1875 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1876 syntax and examples.
  1877 
  1878 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1879 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1880 but the proof obligation additionally includes an admissibility
  1881 requirement. The packages generate instances of class cpo or pcpo,
  1882 with continuity and strictness theorems for Rep and Abs.
  1883 
  1884 * HOLCF: Many theorems have been renamed according to a more standard naming
  1885 scheme (INCOMPATIBILITY):
  1886 
  1887   foo_inject:  "foo$x = foo$y ==> x = y"
  1888   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1889   foo_less:    "(foo$x << foo$y) = (x << y)"
  1890   foo_strict:  "foo$UU = UU"
  1891   foo_defined: "... ==> foo$x ~= UU"
  1892   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1893 
  1894 
  1895 *** ZF ***
  1896 
  1897 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1898 including the First Isomorphism Theorem (on quotienting by the kernel
  1899 of a homomorphism).
  1900 
  1901 * ZF/Simplifier: install second copy of type solver that actually
  1902 makes use of TC rules declared to Isar proof contexts (or locales);
  1903 the old version is still required for ML proof scripts.
  1904 
  1905 
  1906 *** Cube ***
  1907 
  1908 * Converted to Isar theory format; use locales instead of axiomatic
  1909 theories.
  1910 
  1911 
  1912 *** ML ***
  1913 
  1914 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1915 for ||>, ||>>, |>>,
  1916 
  1917 * Pure/library.ML no longer defines its own option datatype, but uses
  1918 that of the SML basis, which has constructors NONE and SOME instead of
  1919 None and Some, as well as exception Option.Option instead of OPTION.
  1920 The functions the, if_none, is_some, is_none have been adapted
  1921 accordingly, while Option.map replaces apsome.
  1922 
  1923 * Pure/library.ML: the exception LIST has been given up in favour of
  1924 the standard exceptions Empty and Subscript, as well as
  1925 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1926 superceded by the standard hd and tl functions etc.
  1927 
  1928 A number of basic list functions are no longer exported to the ML
  1929 toplevel, as they are variants of predefined functions.  The following
  1930 suggests how one can translate existing code:
  1931 
  1932     rev_append xs ys = List.revAppend (xs, ys)
  1933     nth_elem (i, xs) = List.nth (xs, i)
  1934     last_elem xs = List.last xs
  1935     flat xss = List.concat xss
  1936     seq fs = List.app fs
  1937     partition P xs = List.partition P xs
  1938     mapfilter f xs = List.mapPartial f xs
  1939 
  1940 * Pure/library.ML: several combinators for linear functional
  1941 transformations, notably reverse application and composition:
  1942 
  1943   x |> f                f #> g
  1944   (x, y) |-> f          f #-> g
  1945 
  1946 * Pure/library.ML: introduced/changed precedence of infix operators:
  1947 
  1948   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1949   infix 2 ?;
  1950   infix 3 o oo ooo oooo;
  1951   infix 4 ~~ upto downto;
  1952 
  1953 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1954 infix operators.
  1955 
  1956 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1957 fold_map support linear functional transformations and nesting.  For
  1958 example:
  1959 
  1960   fold f [x1, ..., xN] y =
  1961     y |> f x1 |> ... |> f xN
  1962 
  1963   (fold o fold) f [xs1, ..., xsN] y =
  1964     y |> fold f xs1 |> ... |> fold f xsN
  1965 
  1966   fold f [x1, ..., xN] =
  1967     f x1 #> ... #> f xN
  1968 
  1969   (fold o fold) f [xs1, ..., xsN] =
  1970     fold f xs1 #> ... #> fold f xsN
  1971 
  1972 * Pure/library.ML: the following selectors on type 'a option are
  1973 available:
  1974 
  1975   the:               'a option -> 'a  (*partial*)
  1976   these:             'a option -> 'a  where 'a = 'b list
  1977   the_default: 'a -> 'a option -> 'a
  1978   the_list:          'a option -> 'a list
  1979 
  1980 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1981 basic operations for association lists, following natural argument
  1982 order; moreover the explicit equality predicate passed here avoids
  1983 potentially expensive polymorphic runtime equality checks.
  1984 The old functions may be expressed as follows:
  1985 
  1986   assoc = uncurry (AList.lookup (op =))
  1987   assocs = these oo AList.lookup (op =)
  1988   overwrite = uncurry (AList.update (op =)) o swap
  1989 
  1990 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1991 
  1992   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1993   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1994 
  1995 replacing make_keylist and keyfilter (occassionally used)
  1996 Naive rewrites:
  1997 
  1998   make_keylist = AList.make
  1999   keyfilter = AList.find (op =)
  2000 
  2001 * eq_fst and eq_snd now take explicit equality parameter, thus
  2002   avoiding eqtypes. Naive rewrites:
  2003 
  2004     eq_fst = eq_fst (op =)
  2005     eq_snd = eq_snd (op =)
  2006 
  2007 * Removed deprecated apl and apr (rarely used).
  2008   Naive rewrites:
  2009 
  2010     apl (n, op) =>>= curry op n
  2011     apr (op, m) =>>= fn n => op (n, m)
  2012 
  2013 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2014 provides a reasonably efficient light-weight implementation of sets as
  2015 lists.
  2016 
  2017 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2018 few new operations; existing lookup and update are now curried to
  2019 follow natural argument order (for use with fold etc.);
  2020 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2021 
  2022 * Pure/General: output via the Isabelle channels of
  2023 writeln/warning/error etc. is now passed through Output.output, with a
  2024 hook for arbitrary transformations depending on the print_mode
  2025 (cf. Output.add_mode -- the first active mode that provides a output
  2026 function wins).  Already formatted output may be embedded into further
  2027 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2028 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2029 accommodate easy composition of diagnostic messages etc.  Programmers
  2030 rarely need to care about Output.output or Output.raw at all, with
  2031 some notable exceptions: Output.output is required when bypassing the
  2032 standard channels (writeln etc.), or in token translations to produce
  2033 properly formatted results; Output.raw is required when capturing
  2034 already output material that will eventually be presented to the user
  2035 a second time.  For the default print mode, both Output.output and
  2036 Output.raw have no effect.
  2037 
  2038 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2039 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2040 cumulative results are displayed at the end of a batch session.
  2041 
  2042 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2043 replaced by File.platform_path and File.shell_path (with appropriate
  2044 hooks).  This provides a clean interface for unusual systems where the
  2045 internal and external process view of file names are different.
  2046 
  2047 * Pure: more efficient orders for basic syntactic entities: added
  2048 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2049 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2050 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2051 orders now -- potential INCOMPATIBILITY for code that depends on a
  2052 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2053 Library.sort_strings on result).
  2054 
  2055 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2056 fold_types traverse types/terms from left to right, observing natural
  2057 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2058 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2059 
  2060 * Pure: name spaces have been refined, with significant changes of the
  2061 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2062 to extern(_table).  The plain name entry path is superceded by a
  2063 general 'naming' context, which also includes the 'policy' to produce
  2064 a fully qualified name and external accesses of a fully qualified
  2065 name; NameSpace.extend is superceded by context dependent
  2066 Sign.declare_name.  Several theory and proof context operations modify
  2067 the naming context.  Especially note Theory.restore_naming and
  2068 ProofContext.restore_naming to get back to a sane state; note that
  2069 Theory.add_path is no longer sufficient to recover from
  2070 Theory.absolute_path in particular.
  2071 
  2072 * Pure: new flags short_names (default false) and unique_names
  2073 (default true) for controlling output of qualified names.  If
  2074 short_names is set, names are printed unqualified.  If unique_names is
  2075 reset, the name prefix is reduced to the minimum required to achieve
  2076 the original result when interning again, even if there is an overlap
  2077 with earlier declarations.
  2078 
  2079 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2080 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2081 (useful for printing error messages).  INCOMPATIBILITY.
  2082 
  2083 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2084 Theory.theory are now identified, referring to the universal
  2085 Context.theory (see Pure/context.ML).  Actual signature and theory
  2086 content is managed as theory data.  The old code and interfaces were
  2087 spread over many files and structures; the new arrangement introduces
  2088 considerable INCOMPATIBILITY to gain more clarity:
  2089 
  2090   Context -- theory management operations (name, identity, inclusion,
  2091     parents, ancestors, merge, etc.), plus generic theory data;
  2092 
  2093   Sign -- logical signature and syntax operations (declaring consts,
  2094     types, etc.), plus certify/read for common entities;
  2095 
  2096   Theory -- logical theory operations (stating axioms, definitions,
  2097     oracles), plus a copy of logical signature operations (consts,
  2098     types, etc.); also a few basic management operations (Theory.copy,
  2099     Theory.merge, etc.)
  2100 
  2101 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2102 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2103 for convenience -- they merely return the theory.
  2104 
  2105 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2106 
  2107 * Pure: the Isar proof context type is already defined early in Pure
  2108 as Context.proof (note that ProofContext.context and Proof.context are
  2109 aliases, where the latter is the preferred name).  This enables other
  2110 Isabelle components to refer to that type even before Isar is present.
  2111 
  2112 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2113 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2114 any of these kinds.  For example, Sign.intern typeK is now
  2115 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2116 Theory.hide_types.  Also note that former
  2117 Theory.hide_classes/types/consts are now
  2118 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2119 internalize their arguments!  INCOMPATIBILITY.
  2120 
  2121 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2122 datatype thmref (with constructors Name and NameSelection) instead of
  2123 plain string -- INCOMPATIBILITY;
  2124 
  2125 * Pure: cases produced by proof methods specify options, where NONE
  2126 means to remove case bindings -- INCOMPATIBILITY in
  2127 (RAW_)METHOD_CASES.
  2128 
  2129 * Pure: the following operations retrieve axioms or theorems from a
  2130 theory node or theory hierarchy, respectively:
  2131 
  2132   Theory.axioms_of: theory -> (string * term) list
  2133   Theory.all_axioms_of: theory -> (string * term) list
  2134   PureThy.thms_of: theory -> (string * thm) list
  2135   PureThy.all_thms_of: theory -> (string * thm) list
  2136 
  2137 * Pure: print_tac now outputs the goal through the trace channel.
  2138 
  2139 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2140 Reference Toplevel.debug (default false) controls detailed printing
  2141 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2142 controls execution profiling -- set to 1 for time and 2 for space
  2143 (both increase the runtime).
  2144 
  2145 * Isar session: The initial use of ROOT.ML is now always timed,
  2146 i.e. the log will show the actual process times, in contrast to the
  2147 elapsed wall-clock time that the outer shell wrapper produces.
  2148 
  2149 * Simplifier: improved handling of bound variables (nameless
  2150 representation, avoid allocating new strings).  Simprocs that invoke
  2151 the Simplifier recursively should use Simplifier.inherit_bounds to
  2152 avoid local name clashes.  Failure to do so produces warnings
  2153 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2154 for further details.
  2155 
  2156 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2157 bindings for all theorems stored within a given theory; this may help
  2158 in porting non-Isar theories to Isar ones, while keeping ML proof
  2159 scripts for the time being.
  2160 
  2161 * ML operator HTML.with_charset specifies the charset begin used for
  2162 generated HTML files.  For example:
  2163 
  2164   HTML.with_charset "utf-8" use_thy "Hebrew";
  2165   HTML.with_charset "utf-8" use_thy "Chinese";
  2166 
  2167 
  2168 *** System ***
  2169 
  2170 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2171 isabelle, isatool etc.).
  2172 
  2173 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2174 isatool doc, isatool mkdir, display_drafts etc.).
  2175 
  2176 * isatool usedir: option -f allows specification of the ML file to be
  2177 used by Isabelle; default is ROOT.ML.
  2178 
  2179 * New isatool version outputs the version identifier of the Isabelle
  2180 distribution being used.
  2181 
  2182 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2183 (containing Boolean satisfiability problems) into Isabelle/HOL
  2184 theories.
  2185 
  2186 
  2187 
  2188 New in Isabelle2004 (April 2004)
  2189 --------------------------------
  2190 
  2191 *** General ***
  2192 
  2193 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2194   Replaces linorder.ML.
  2195 
  2196 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2197   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2198   (\<a>...\<z>), are now considered normal letters, and can therefore
  2199   be used anywhere where an ASCII letter (a...zA...Z) has until
  2200   now. COMPATIBILITY: This obviously changes the parsing of some
  2201   terms, especially where a symbol has been used as a binder, say
  2202   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2203   as an identifier.  Fix it by inserting a space around former
  2204   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2205   existing theory and ML files.
  2206 
  2207 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2208 
  2209 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2210   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2211   a normal (but invisible) letter. For multiple letter subscripts repeat
  2212   \<^isub> like this: x\<^isub>1\<^isub>2.
  2213 
  2214 * Pure: There are now sub-/superscripts that can span more than one
  2215   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2216   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2217   superscript. The new control characters are not identifier parts.
  2218 
  2219 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2220   content of "..." to the latex file instead of \isacntrl... . The "..."
  2221   may consist of any printable characters excluding the end bracket >.
  2222 
  2223 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2224   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2225   declare constants "final", which prevents their being given a definition
  2226   later.  It is useful for constants whose behaviour is fixed axiomatically
  2227   rather than definitionally, such as the meta-logic connectives.
  2228 
  2229 * Pure: 'instance' now handles general arities with general sorts
  2230   (i.e. intersections of classes),
  2231 
  2232 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2233   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2234   It can be changed to alter the colors/layout of generated pages.
  2235 
  2236 
  2237 *** Isar ***
  2238 
  2239 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2240   cut_tac, subgoal_tac and thin_tac:
  2241   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2242     locales are no longer forced to write Isar proof scripts.
  2243     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2244     emulations.
  2245   - INCOMPATIBILITY: names of variables to be instantiated may no
  2246     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2247     This is consistent with the instantiation attribute "where".
  2248 
  2249 * Attributes "where" and "of":
  2250   - Now take type variables of instantiated theorem into account when reading
  2251     the instantiation string.  This fixes a bug that caused instantiated
  2252     theorems to have too special types in some circumstances.
  2253   - "where" permits explicit instantiations of type variables.
  2254 
  2255 * Calculation commands "moreover" and "also" no longer interfere with
  2256   current facts ("this"), admitting arbitrary combinations with "then"
  2257   and derived forms.
  2258 
  2259 * Locales:
  2260   - Goal statements involving the context element "includes" no longer
  2261     generate theorems with internal delta predicates (those ending on
  2262     "_axioms") in the premise.
  2263     Resolve particular premise with <locale>.intro to obtain old form.
  2264   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2265     specification and "includes" elements in goal statement.
  2266   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2267     [intro?] and [elim?] (respectively) by default.
  2268   - Experimental command for instantiation of locales in proof contexts:
  2269         instantiate <label>[<attrs>]: <loc>
  2270     Instantiates locale <loc> and adds all its theorems to the current context
  2271     taking into account their attributes.  Label and attrs are optional
  2272     modifiers, like in theorem declarations.  If present, names of
  2273     instantiated theorems are qualified with <label>, and the attributes
  2274     <attrs> are applied after any attributes these theorems might have already.
  2275       If the locale has assumptions, a chained fact of the form
  2276     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2277     are derived.  The command does not support old-style locales declared
  2278     with "locale (open)".
  2279       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2280 
  2281 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2282   (Isar) contexts.
  2283 
  2284 
  2285 *** HOL ***
  2286 
  2287 * Proof import: new image HOL4 contains the imported library from
  2288   the HOL4 system with about 2500 theorems. It is imported by
  2289   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2290   can be used like any other Isabelle image.  See
  2291   HOL/Import/HOL/README for more information.
  2292 
  2293 * Simplifier:
  2294   - Much improved handling of linear and partial orders.
  2295     Reasoners for linear and partial orders are set up for type classes
  2296     "linorder" and "order" respectively, and are added to the default simpset
  2297     as solvers.  This means that the simplifier can build transitivity chains
  2298     to solve goals from the assumptions.
  2299   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2300     of blast or auto after simplification become unnecessary because the goal
  2301     is solved by simplification already.
  2302 
  2303 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2304     all proved in axiomatic type classes for semirings, rings and fields.
  2305 
  2306 * Numerics:
  2307   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2308     now formalized using the Ring_and_Field theory mentioned above.
  2309   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2310     than before, because now they are set up once in a generic manner.
  2311   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2312     Look for the general versions in Ring_and_Field (and Power if they concern
  2313     exponentiation).
  2314 
  2315 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2316 
  2317 * Records:
  2318   - Record types are now by default printed with their type abbreviation
  2319     instead of the list of all field types. This can be configured via
  2320     the reference "print_record_type_abbr".
  2321   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2322     (not enabled by default).
  2323   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2324     EX x. x = sel r to True (not enabled by default).
  2325   - Tactic "record_split_simp_tac" to split and simplify records added.
  2326 
  2327 * 'specification' command added, allowing for definition by
  2328   specification.  There is also an 'ax_specification' command that
  2329   introduces the new constants axiomatically.
  2330 
  2331 * arith(_tac) is now able to generate counterexamples for reals as well.
  2332 
  2333 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2334 
  2335 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2336   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2337 
  2338 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2339   matrix theory to linear programming.
  2340 
  2341 * Unions and Intersections:
  2342   The latex output syntax of UN and INT has been changed
  2343   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2344   i.e. the index formulae has become a subscript.
  2345   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2346 
  2347 * Unions and Intersections over Intervals:
  2348   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2349   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2350   like in normal math, and corresponding versions for < and for intersection.
  2351 
  2352 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2353   lexicographic dictonary ordering has been added as "lexord".
  2354 
  2355 * ML: the legacy theory structures Int and List have been removed. They had
  2356   conflicted with ML Basis Library structures having the same names.
  2357 
  2358 * 'refute' command added to search for (finite) countermodels.  Only works
  2359   for a fragment of HOL.  The installation of an external SAT solver is
  2360   highly recommended.  See "HOL/Refute.thy" for details.
  2361 
  2362 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2363   formulae under an assignment of free variables to random values.
  2364   In contrast to 'refute', it can deal with inductive datatypes,
  2365   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2366   for examples.
  2367 
  2368 
  2369 *** HOLCF ***
  2370 
  2371 * Streams now come with concatenation and are part of the HOLCF image
  2372 
  2373 
  2374 
  2375 New in Isabelle2003 (May 2003)
  2376 ------------------------------
  2377 
  2378 *** General ***
  2379 
  2380 * Provers/simplifier:
  2381 
  2382   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2383     Assumptions are now subject to complete mutual simplification,
  2384     not just from left to right. The simplifier now preserves
  2385     the order of assumptions.
  2386 
  2387     Potential INCOMPATIBILITY:
  2388 
  2389     -- simp sometimes diverges where the old version did
  2390        not, e.g. invoking simp on the goal
  2391 
  2392         [| P (f x); y = x; f x = f y |] ==> Q
  2393 
  2394        now gives rise to the infinite reduction sequence
  2395 
  2396         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2397 
  2398        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2399        kind of problem.
  2400 
  2401     -- Tactics combining classical reasoner and simplification (such as auto)
  2402        are also affected by this change, because many of them rely on
  2403        simp. They may sometimes diverge as well or yield a different numbers
  2404        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2405        in case of problems. Sometimes subsequent calls to the classical
  2406        reasoner will fail because a preceeding call to the simplifier too
  2407        eagerly simplified the goal, e.g. deleted redundant premises.
  2408 
  2409   - The simplifier trace now shows the names of the applied rewrite rules
  2410 
  2411   - You can limit the number of recursive invocations of the simplifier
  2412     during conditional rewriting (where the simplifie tries to solve the
  2413     conditions before applying the rewrite rule):
  2414     ML "simp_depth_limit := n"
  2415     where n is an integer. Thus you can force termination where previously
  2416     the simplifier would diverge.
  2417 
  2418   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2419 
  2420   - No longer aborts on failed congruence proof.  Instead, the
  2421     congruence is ignored.
  2422 
  2423 * Pure: New generic framework for extracting programs from constructive
  2424   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2425   as HOL/Extraction for some case studies.
  2426 
  2427 * Pure: The main goal of the proof state is no longer shown by default, only
  2428 the subgoals. This behaviour is controlled by a new flag.
  2429    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2430 (ML: Proof.show_main_goal).
  2431 
  2432 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2433 rules whose conclusion matches subgoal 1:
  2434       PG menu: Isabelle/Isar -> Show me -> matching rules
  2435 The rules are ordered by how closely they match the subgoal.
  2436 In particular, rules that solve a subgoal outright are displayed first
  2437 (or rather last, the way they are printed).
  2438 (ML: ProofGeneral.print_intros())
  2439 
  2440 * Pure: New flag trace_unify_fail causes unification to print
  2441 diagnostic information (PG: in trace buffer) when it fails. This is
  2442 useful for figuring out why single step proofs like rule, erule or
  2443 assumption failed.
  2444 
  2445 * Pure: Locale specifications now produce predicate definitions
  2446 according to the body of text (covering assumptions modulo local
  2447 definitions); predicate "loc_axioms" covers newly introduced text,
  2448 while "loc" is cumulative wrt. all included locale expressions; the
  2449 latter view is presented only on export into the global theory
  2450 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2451 on the old view without predicates;
  2452 
  2453 * Pure: predefined locales "var" and "struct" are useful for sharing
  2454 parameters (as in CASL, for example); just specify something like
  2455 ``var x + var y + struct M'' as import;
  2456 
  2457 * Pure: improved thms_containing: proper indexing of facts instead of
  2458 raw theorems; check validity of results wrt. current name space;
  2459 include local facts of proof configuration (also covers active
  2460 locales), cover fixed variables in index; may use "_" in term
  2461 specification; an optional limit for the number of printed facts may
  2462 be given (the default is 40);
  2463 
  2464 * Pure: disallow duplicate fact bindings within new-style theory files
  2465 (batch-mode only);
  2466 
  2467 * Provers: improved induct method: assumptions introduced by case
  2468 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2469 the goal statement); "foo" still refers to all facts collectively;
  2470 
  2471 * Provers: the function blast.overloaded has been removed: all constants
  2472 are regarded as potentially overloaded, which improves robustness in exchange
  2473 for slight decrease in efficiency;
  2474 
  2475 * Provers/linorder: New generic prover for transitivity reasoning over
  2476 linear orders.  Note: this prover is not efficient!
  2477 
  2478 * Isar: preview of problems to finish 'show' now produce an error
  2479 rather than just a warning (in interactive mode);
  2480 
  2481 
  2482 *** HOL ***
  2483 
  2484 * arith(_tac)
  2485 
  2486  - Produces a counter example if it cannot prove a goal.
  2487    Note that the counter example may be spurious if the goal is not a formula
  2488    of quantifier-free linear arithmetic.
  2489    In ProofGeneral the counter example appears in the trace buffer.
  2490 
  2491  - Knows about div k and mod k where k is a numeral of type nat or int.
  2492 
  2493  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2494    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2495    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2496 
  2497 * simp's arithmetic capabilities have been enhanced a bit: it now
  2498 takes ~= in premises into account (by performing a case split);
  2499 
  2500 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2501 are distributed over a sum of terms;
  2502 
  2503 * New tactic "trans_tac" and method "trans" instantiate
  2504 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2505 "<=", "<" and "=").
  2506 
  2507 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2508 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2509 
  2510 * 'typedef' command has new option "open" to suppress the set
  2511 definition;
  2512 
  2513 * functions Min and Max on finite sets have been introduced (theory
  2514 Finite_Set);
  2515 
  2516 * attribute [symmetric] now works for relations as well; it turns
  2517 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2518 
  2519 * induct over a !!-quantified statement (say !!x1..xn):
  2520   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2521 
  2522 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2523 %x. None. Warning: empty_def now refers to the previously hidden definition
  2524 of the empty set.
  2525 
  2526 * Algebra: formalization of classical algebra.  Intended as base for
  2527 any algebraic development in Isabelle.  Currently covers group theory
  2528 (up to Sylow's theorem) and ring theory (Universal Property of
  2529 Univariate Polynomials).  Contributions welcome;
  2530 
  2531 * GroupTheory: deleted, since its material has been moved to Algebra;
  2532 
  2533 * Complex: new directory of the complex numbers with numeric constants,
  2534 nonstandard complex numbers, and some complex analysis, standard and
  2535 nonstandard (Jacques Fleuriot);
  2536 
  2537 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2538 
  2539 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2540 Fleuriot);
  2541 
  2542 * Real/HahnBanach: updated and adapted to locales;
  2543 
  2544 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2545 Gray and Kramer);
  2546 
  2547 * UNITY: added the Meier-Sanders theory of progress sets;
  2548 
  2549 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2550 as abstract algorithms, instantiated to the JVM;
  2551 
  2552 * Bali: Java source language formalization. Type system, operational
  2553 semantics, axiomatic semantics. Supported language features:
  2554 classes, interfaces, objects,virtual methods, static methods,
  2555 static/instance fields, arrays, access modifiers, definite
  2556 assignment, exceptions.
  2557 
  2558 
  2559 *** ZF ***
  2560 
  2561 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2562 universe, etc.);
  2563 
  2564 * Main ZF: virtually all theories converted to new-style format;
  2565 
  2566 
  2567 *** ML ***
  2568 
  2569 * Pure: Tactic.prove provides sane interface for internal proofs;
  2570 omits the infamous "standard" operation, so this is more appropriate
  2571 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2572 
  2573 * Pure: improved error reporting of simprocs;
  2574 
  2575 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2576 up simprocs;
  2577 
  2578 
  2579 *** Document preparation ***
  2580 
  2581 * uses \par instead of \\ for line breaks in theory text. This may
  2582 shift some page breaks in large documents. To get the old behaviour
  2583 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2584 
  2585 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2586 other packages
  2587 
  2588 * \<euro> now needs package babel/greek instead of marvosym (which
  2589 broke \Rightarrow)
  2590 
  2591 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2592 textcomp package)
  2593 
  2594 
  2595 
  2596 New in Isabelle2002 (March 2002)
  2597 --------------------------------
  2598 
  2599 *** Document preparation ***
  2600 
  2601 * greatly simplified document preparation setup, including more
  2602 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2603 instructive isatool mkdir; users should basically be able to get
  2604 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2605 users may run a separate document processing stage manually like this:
  2606 "isatool usedir -D output HOL Test && isatool document Test/output";
  2607 
  2608 * theory dependency graph may now be incorporated into documents;
  2609 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2610 with \includegraphics of LaTeX;
  2611 
  2612 * proper spacing of consecutive markup elements, especially text
  2613 blocks after section headings;
  2614 
  2615 * support bold style (for single symbols only), input syntax is like
  2616 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2617 
  2618 * \<bullet> is now output as bold \cdot by default, which looks much
  2619 better in printed text;
  2620 
  2621 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2622 note that these symbols are currently unavailable in Proof General /
  2623 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2624 
  2625 * isatool latex no longer depends on changed TEXINPUTS, instead
  2626 isatool document copies the Isabelle style files to the target
  2627 location;
  2628 
  2629 
  2630 *** Isar ***
  2631 
  2632 * Pure/Provers: improved proof by cases and induction;
  2633   - 'case' command admits impromptu naming of parameters (such as
  2634     "case (Suc n)");
  2635   - 'induct' method divinates rule instantiation from the inductive
  2636     claim; no longer requires excessive ?P bindings for proper
  2637     instantiation of cases;
  2638   - 'induct' method properly enumerates all possibilities of set/type
  2639     rules; as a consequence facts may be also passed through *type*
  2640     rules without further ado;
  2641   - 'induct' method now derives symbolic cases from the *rulified*
  2642     rule (before it used to rulify cases stemming from the internal
  2643     atomized version); this means that the context of a non-atomic
  2644     statement becomes is included in the hypothesis, avoiding the
  2645     slightly cumbersome show "PROP ?case" form;
  2646   - 'induct' may now use elim-style induction rules without chaining
  2647     facts, using ``missing'' premises from the goal state; this allows
  2648     rules stemming from inductive sets to be applied in unstructured
  2649     scripts, while still benefitting from proper handling of non-atomic
  2650     statements; NB: major inductive premises need to be put first, all
  2651     the rest of the goal is passed through the induction;
  2652   - 'induct' proper support for mutual induction involving non-atomic
  2653     rule statements (uses the new concept of simultaneous goals, see
  2654     below);
  2655   - append all possible rule selections, but only use the first
  2656     success (no backtracking);
  2657   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2658   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2659   - added 'print_induct_rules' (covered by help item in recent Proof
  2660     General versions);
  2661   - moved induct/cases attributes to Pure, methods to Provers;
  2662   - generic method setup instantiated for FOL and HOL;
  2663 
  2664 * Pure: support multiple simultaneous goal statements, for example
  2665 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2666 meta-level mechanism, this acts as if several individual goals had
  2667 been stated separately; in particular common proof methods need to be
  2668 repeated in order to cover all claims; note that a single elimination
  2669 step is *not* sufficient to establish the two conjunctions, so this
  2670 fails:
  2671 
  2672   assume "A & B" then have A and B ..   (*".." fails*)
  2673 
  2674 better use "obtain" in situations as above; alternative refer to
  2675 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2676 
  2677 * Pure: proper integration with ``locales''; unlike the original
  2678 version by Florian Kammller, Isar locales package high-level proof
  2679 contexts rather than raw logical ones (e.g. we admit to include
  2680 attributes everywhere); operations on locales include merge and
  2681 rename; support for implicit arguments (``structures''); simultaneous
  2682 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2683 some examples;
  2684 
  2685 * Pure: the following commands have been ``localized'', supporting a
  2686 target locale specification "(in name)": 'lemma', 'theorem',
  2687 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2688 stored both within the locale and at the theory level (exported and
  2689 qualified by the locale name);
  2690 
  2691 * Pure: theory goals may now be specified in ``long'' form, with
  2692 ad-hoc contexts consisting of arbitrary locale elements. for example
  2693 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2694 definitions may be given, too); the result is a meta-level rule with
  2695 the context elements being discharged in the obvious way;
  2696 
  2697 * Pure: new proof command 'using' allows to augment currently used
  2698 facts after a goal statement ('using' is syntactically analogous to
  2699 'apply', but acts on the goal's facts only); this allows chained facts
  2700 to be separated into parts given before and after a claim, as in
  2701 ``from a and b have C using d and e <proof>'';
  2702 
  2703 * Pure: renamed "antecedent" case to "rule_context";
  2704 
  2705 * Pure: new 'judgment' command records explicit information about the
  2706 object-logic embedding (used by several tools internally); no longer
  2707 use hard-wired "Trueprop";
  2708 
  2709 * Pure: added 'corollary' command;
  2710 
  2711 * Pure: fixed 'token_translation' command;
  2712 
  2713 * Pure: removed obsolete 'exported' attribute;
  2714 
  2715 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2716 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2717 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2718 
  2719 * Pure: method 'atomize' presents local goal premises as object-level
  2720 statements (atomic meta-level propositions); setup controlled via
  2721 rewrite rules declarations of 'atomize' attribute; example
  2722 application: 'induct' method with proper rule statements in improper
  2723 proof *scripts*;
  2724 
  2725 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2726 now consider the syntactic context of assumptions, giving a better
  2727 chance to get type-inference of the arguments right (this is
  2728 especially important for locales);
  2729 
  2730 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2731 mode;
  2732 
  2733 * Pure/obtain: the formal conclusion "thesis", being marked as
  2734 ``internal'', may no longer be reference directly in the text;
  2735 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2736 situations;
  2737 
  2738 * Pure: generic 'sym' attribute which declares a rule both as pure
  2739 'elim?' and for the 'symmetric' operation;
  2740 
  2741 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2742 text; the fixed correlation with particular command syntax has been
  2743 discontinued;
  2744 
  2745 * Pure: new method 'rules' is particularly well-suited for proof
  2746 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2747 but often produces more compact proof terms with less detours;
  2748 
  2749 * Pure/Provers/classical: simplified integration with pure rule
  2750 attributes and methods; the classical "intro?/elim?/dest?"
  2751 declarations coincide with the pure ones; the "rule" method no longer
  2752 includes classically swapped intros; "intro" and "elim" methods no
  2753 longer pick rules from the context; also got rid of ML declarations
  2754 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2755 INCOMPATIBILITY;
  2756 
  2757 * Provers/classical: attribute 'swapped' produces classical inversions
  2758 of introduction rules;
  2759 
  2760 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2761 rules instead of full simplifier context; 'iff' attribute handles
  2762 conditional rules;
  2763 
  2764 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2765 
  2766 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2767 "(permissive)" option to recover old behavior;
  2768 
  2769 * HOL: 'inductive' no longer features separate (collective) attributes
  2770 for 'intros' (was found too confusing);
  2771 
  2772 * HOL: properly declared induction rules less_induct and
  2773 wf_induct_rule;
  2774 
  2775 
  2776 *** HOL ***
  2777 
  2778 * HOL: moved over to sane numeral syntax; the new policy is as
  2779 follows:
  2780 
  2781   - 0 and 1 are polymorphic constants, which are defined on any
  2782   numeric type (nat, int, real etc.);
  2783 
  2784   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2785   binary representation internally;
  2786 
  2787   - type nat has special constructor Suc, and generally prefers Suc 0
  2788   over 1::nat and Suc (Suc 0) over 2::nat;
  2789 
  2790 This change may cause significant problems of INCOMPATIBILITY; here
  2791 are some hints on converting existing sources:
  2792 
  2793   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2794   entities, so expressions involving "-" (unary or binary minus) need
  2795   to be spaced properly;
  2796 
  2797   - existing occurrences of "1" may need to be constraint "1::nat" or
  2798   even replaced by Suc 0; similar for old "2";
  2799 
  2800   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2801 
  2802   - remove all special provisions on numerals in proofs;
  2803 
  2804 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2805 representation (depends on bin_arith_simps in the default context);
  2806 
  2807 * HOL: symbolic syntax for x^2 (numeral 2);
  2808 
  2809 * HOL: the class of all HOL types is now called "type" rather than
  2810 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2811 in axclass/classes, instance/arities, and (usually rare) occurrences
  2812 in typings (of consts etc.); internally the class is called
  2813 "HOL.type", ML programs should refer to HOLogic.typeS;
  2814 
  2815 * HOL/record package improvements:
  2816   - new derived operations "fields" to build a partial record section,
  2817     "extend" to promote a fixed record to a record scheme, and
  2818     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2819     declared as simp by default;
  2820   - shared operations ("more", "fields", etc.) now need to be always
  2821     qualified) --- potential INCOMPATIBILITY;
  2822   - removed "make_scheme" operations (use "make" with "extend") --
  2823     INCOMPATIBILITY;
  2824   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2825   - provides cases/induct rules for use with corresponding Isar
  2826     methods (for concrete records, record schemes, concrete more
  2827     parts, and schematic more parts -- in that order);
  2828   - internal definitions directly based on a light-weight abstract
  2829     theory of product types over typedef rather than datatype;
  2830 
  2831 * HOL: generic code generator for generating executable ML code from
  2832 specifications; specific support for HOL constructs such as inductive
  2833 datatypes and sets, as well as recursive functions; can be invoked
  2834 via 'generate_code' theory section;
  2835 
  2836 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2837 
  2838 * HOL: consolidated and renamed several theories.  In particular:
  2839         Ord.thy has been absorbed into HOL.thy
  2840         String.thy has been absorbed into List.thy
  2841 
  2842 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2843 (beware of argument permutation!);
  2844 
  2845 * HOL: linorder_less_split superseded by linorder_cases;
  2846 
  2847 * HOL/List: "nodups" renamed to "distinct";
  2848 
  2849 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2850 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2851   - Ex_def has changed, now need to use some_eq_ex
  2852 
  2853 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2854 in this (rare) case use:
  2855 
  2856   delSWrapper "split_all_tac"
  2857   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2858 
  2859 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2860 MAY FAIL;
  2861 
  2862 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2863 Isabelle's type classes, ^ on functions and relations has too general
  2864 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2865 necessary to attach explicit type constraints;
  2866 
  2867 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2868 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2869 renamed accordingly (eg "compI" -> "rel_compI").
  2870 
  2871 * HOL: syntax translations now work properly with numerals and records
  2872 expressions;
  2873 
  2874 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2875 of "lam" -- INCOMPATIBILITY;
  2876 
  2877 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2878 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2879 renamed "Product_Type.unit";
  2880 
  2881 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2882 
  2883 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2884 the "cases" method);
  2885 
  2886 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2887 Florian Kammller);
  2888 
  2889 * HOL/IMP: updated and converted to new-style theory format; several
  2890 parts turned into readable document, with proper Isar proof texts and
  2891 some explanations (by Gerwin Klein);
  2892 
  2893 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2894 
  2895 * HOL-Hyperreal is now a logic image;
  2896 
  2897 
  2898 *** HOLCF ***
  2899 
  2900 * Isar: consts/constdefs supports mixfix syntax for continuous
  2901 operations;
  2902 
  2903 * Isar: domain package adapted to new-style theory format, e.g. see
  2904 HOLCF/ex/Dnat.thy;
  2905 
  2906 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2907 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2908 lift.induct_tac, always use UU instead of Undef;
  2909 
  2910 * HOLCF/IMP: updated and converted to new-style theory;
  2911 
  2912 
  2913 *** ZF ***
  2914 
  2915 * Isar: proper integration of logic-specific tools and packages,
  2916 including theory commands '(co)inductive', '(co)datatype',
  2917 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2918 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2919 
  2920 * theory Main no longer includes AC; for the Axiom of Choice, base
  2921 your theory on Main_ZFC;
  2922 
  2923 * the integer library now covers quotients and remainders, with many
  2924 laws relating division to addition, multiplication, etc.;
  2925 
  2926 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2927 typeless version of the formalism;
  2928 
  2929 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2930 format;
  2931 
  2932 * ZF/Induct: new directory for examples of inductive definitions,
  2933 including theory Multiset for multiset orderings; converted to
  2934 new-style theory format;
  2935 
  2936 * ZF: many new theorems about lists, ordinals, etc.;
  2937 
  2938 
  2939 *** General ***
  2940 
  2941 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2942 variable proof controls level of detail: 0 = no proofs (only oracle
  2943 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2944 also ref manual for further ML interfaces;
  2945 
  2946 * Pure/axclass: removed obsolete ML interface
  2947 goal_subclass/goal_arity;
  2948 
  2949 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2950 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2951 separate tokens, so expressions involving minus need to be spaced
  2952 properly;
  2953 
  2954 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2955 rather than "infixl" or "infixr";
  2956 
  2957 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2958 sort constraint specifications in type inference; e.g. "x::_::foo"
  2959 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2960 type variable);
  2961 
  2962 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2963 control output of nested => (types); the default behavior is
  2964 "type_brackets";
  2965 
  2966 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2967 tokens into AST constants;
  2968 
  2969 * Pure/syntax: prefer later declarations of translations and print
  2970 translation functions; potential INCOMPATIBILITY: need to reverse
  2971 multiple declarations for same syntax element constant;
  2972 
  2973 * Pure/show_hyps reset by default (in accordance to existing Isar
  2974 practice);
  2975 
  2976 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2977 addSafter;
  2978 
  2979 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2980 as well;
  2981 
  2982 * system: tested support for MacOS X; should be able to get Isabelle +
  2983 Proof General to work in a plain Terminal after installing Poly/ML
  2984 (e.g. from the Isabelle distribution area) and GNU bash alone
  2985 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2986 support requires further installations, e.g. from
  2987 http://fink.sourceforge.net/);
  2988 
  2989 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2990 
  2991 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2992 of 40 MB), cf. ML_OPTIONS;
  2993 
  2994 * system: Proof General keywords specification is now part of the
  2995 Isabelle distribution (see etc/isar-keywords.el);
  2996 
  2997 * system: support for persistent Proof General sessions (refrain from
  2998 outdating all loaded theories on startup); user may create writable
  2999 logic images like this: ``isabelle -q HOL Test'';
  3000 
  3001 * system: smart selection of Isabelle process versus Isabelle
  3002 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3003 run both "isabelle" and "Isabelle" even if file names are badly
  3004 damaged (executable inspects the case of the first letter of its own
  3005 name); added separate "isabelle-process" and "isabelle-interface";
  3006 
  3007 * system: refrain from any attempt at filtering input streams; no
  3008 longer support ``8bit'' encoding of old isabelle font, instead proper
  3009 iso-latin characters may now be used; the related isatools
  3010 "symbolinput" and "nonascii" have disappeared as well;
  3011 
  3012 * system: removed old "xterm" interface (the print modes "xterm" and
  3013 "xterm_color" are still available for direct use in a suitable
  3014 terminal);
  3015 
  3016 
  3017 
  3018 New in Isabelle99-2 (February 2001)
  3019 -----------------------------------
  3020 
  3021 *** Overview of INCOMPATIBILITIES ***
  3022 
  3023 * HOL: please note that theories in the Library and elsewhere often use the
  3024 new-style (Isar) format; to refer to their theorems in an ML script you must
  3025 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3026 
  3027 * HOL: inductive package no longer splits induction rule aggressively,
  3028 but only as far as specified by the introductions given; the old
  3029 format may be recovered via ML function complete_split_rule or attribute
  3030 'split_rule (complete)';
  3031 
  3032 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3033 gfp_Tarski to gfp_unfold;
  3034 
  3035 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3036 
  3037 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3038 relation); infix "^^" has been renamed "``"; infix "``" has been
  3039 renamed "`"; "univalent" has been renamed "single_valued";
  3040 
  3041 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3042 operation;
  3043 
  3044 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3045 
  3046 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3047 
  3048 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3049 consequence, it is no longer monotonic wrt. the local goal context
  3050 (which is now passed through the inductive cases);
  3051 
  3052 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3053 \<gg> to \<ggreater>;
  3054 
  3055 
  3056 *** Document preparation ***
  3057 
  3058 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3059 available: are "it" for near math-mode best-style output, "sl" for
  3060 slanted text style, and "tt" for plain type-writer; if no
  3061 \isabellestyle command is given, output is according to slanted
  3062 type-writer);
  3063 
  3064 * support sub/super scripts (for single symbols only), input syntax is
  3065 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3066 
  3067 * some more standard symbols; see Appendix A of the system manual for
  3068 the complete list of symbols defined in isabellesym.sty;
  3069 
  3070 * improved isabelle style files; more abstract symbol implementation
  3071 (should now use \isamath{...} and \isatext{...} in custom symbol
  3072 definitions);
  3073 
  3074 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3075 state; Note that presentation of goal states does not conform to
  3076 actual human-readable proof documents.  Please do not include goal
  3077 states into document output unless you really know what you are doing!
  3078 
  3079 * proper indentation of antiquoted output with proportional LaTeX
  3080 fonts;
  3081 
  3082 * no_document ML operator temporarily disables LaTeX document
  3083 generation;
  3084 
  3085 * isatool unsymbolize tunes sources for plain ASCII communication;
  3086 
  3087 
  3088 *** Isar ***
  3089 
  3090 * Pure: Isar now suffers initial goal statements to contain unbound
  3091 schematic variables (this does not conform to actual readable proof
  3092 documents, due to unpredictable outcome and non-compositional proof
  3093 checking); users who know what they are doing may use schematic goals
  3094 for Prolog-style synthesis of proven results;
  3095 
  3096 * Pure: assumption method (an implicit finishing) now handles actual
  3097 rules as well;
  3098 
  3099 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3100 initial goal, declare "that" only as Pure intro (only for single
  3101 steps); the "that" rule assumption may now be involved in implicit
  3102 finishing, thus ".." becomes a feasible for trivial obtains;
  3103 
  3104 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3105 instance proofs may be performed by "..";
  3106 
  3107 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3108 statements as well;
  3109 
  3110 * Pure: more robust selection of calculational rules;
  3111 
  3112 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3113 rule (as well as the assumption rule);
  3114 
  3115 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3116 lemmas, using the graph browser tool;
  3117 
  3118 * Pure: predict failure of "show" in interactive mode;
  3119 
  3120 * Pure: 'thms_containing' now takes actual terms as arguments;
  3121 
  3122 * HOL: improved method 'induct' --- now handles non-atomic goals
  3123 (potential INCOMPATIBILITY); tuned error handling;
  3124 
  3125 * HOL: cases and induct rules now provide explicit hints about the
  3126 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3127 any remaining facts are inserted into the goal verbatim;
  3128 
  3129 * HOL: local contexts (aka cases) may now contain term bindings as
  3130 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3131 the result to be shown in each case;
  3132 
  3133 * HOL: added 'recdef_tc' command;
  3134 
  3135 * isatool convert assists in eliminating legacy ML scripts;
  3136 
  3137 
  3138 *** HOL ***
  3139 
  3140 * HOL/Library: a collection of generic theories to be used together
  3141 with main HOL; the theory loader path already includes this directory
  3142 by default; the following existing theories have been moved here:
  3143 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3144 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3145 
  3146 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3147 modelling and verification task performed in Isabelle/HOL +
  3148 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3149 
  3150 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3151 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3152 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3153 'domain', this makes the theory consistent with mathematical
  3154 literature;
  3155 
  3156 * HOL basics: added overloaded operations "inverse" and "divide"
  3157 (infix "/"), syntax for generic "abs" operation, generic summation
  3158 operator \<Sum>;
  3159 
  3160 * HOL/typedef: simplified package, provide more useful rules (see also
  3161 HOL/subset.thy);
  3162 
  3163 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3164 now expressed as a proper nested rule (old-style tactic scripts may
  3165 require atomize_strip_tac to cope with non-atomic premises);
  3166 
  3167 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3168 to "split_conv" (old name still available for compatibility);
  3169 
  3170 * HOL: improved concrete syntax for strings (e.g. allows translation
  3171 rules with string literals);
  3172 
  3173 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3174  and Fleuriot's mechanization of analysis, including the transcendental
  3175  functions for the reals;
  3176 
  3177 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3178 
  3179 
  3180 *** CTT ***
  3181 
  3182 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3183 "lam" is displayed as TWO lambda-symbols
  3184 
  3185 * CTT: theory Main now available, containing everything (that is, Bool
  3186 and Arith);
  3187 
  3188 
  3189 *** General ***
  3190 
  3191 * Pure: the Simplifier has been implemented properly as a derived rule
  3192 outside of the actual kernel (at last!); the overall performance
  3193 penalty in practical applications is about 50%, while reliability of
  3194 the Isabelle inference kernel has been greatly improved;
  3195 
  3196 * print modes "brackets" and "no_brackets" control output of nested =>
  3197 (types) and ==> (props); the default behaviour is "brackets";
  3198 
  3199 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3200 as assumptions as well;
  3201 
  3202 * system: support Poly/ML 4.0;
  3203 
  3204 * system: isatool install handles KDE version 1 or 2;
  3205 
  3206 
  3207 
  3208 New in Isabelle99-1 (October 2000)
  3209 ----------------------------------
  3210 
  3211 *** Overview of INCOMPATIBILITIES ***
  3212 
  3213 * HOL: simplification of natural numbers is much changed; to partly
  3214 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3215 issue the following ML commands:
  3216 
  3217   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3218   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3219 
  3220 * HOL: simplification no longer dives into case-expressions; this is
  3221 controlled by "t.weak_case_cong" for each datatype t;
  3222 
  3223 * HOL: nat_less_induct renamed to less_induct;
  3224 
  3225 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3226 fixsome to patch .thy and .ML sources automatically;
  3227 
  3228   select_equality  -> some_equality
  3229   select_eq_Ex     -> some_eq_ex
  3230   selectI2EX       -> someI2_ex
  3231   selectI2         -> someI2
  3232   selectI          -> someI
  3233   select1_equality -> some1_equality
  3234   Eps_sym_eq       -> some_sym_eq_trivial
  3235   Eps_eq           -> some_eq_trivial
  3236 
  3237 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3238 
  3239 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3240 instead);
  3241 
  3242 * HOL: the recursion equations generated by 'recdef' are now called
  3243 f.simps instead of f.rules;
  3244 
  3245 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3246 
  3247 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3248 sometimes be needed;
  3249 
  3250 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3251 
  3252 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3253 
  3254 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3255 product is now "<*>" instead of "Times"; the lexicographic product is
  3256 now "<*lex*>" instead of "**";
  3257 
  3258 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3259 of main HOL, but was unused); better use HOL's datatype package;
  3260 
  3261 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3262 the old syntax may be recovered as follows:
  3263 
  3264   syntax (symbols)
  3265     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3266       (infixl "\\<oplus>" 100)
  3267 
  3268 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3269 
  3270 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3271 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3272 internally;
  3273 
  3274 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3275 changed from A/r to A//r;
  3276 
  3277 * ZF: new treatment of arithmetic (nat & int) may break some old
  3278 proofs;
  3279 
  3280 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3281 rulify -> rule_format, elimify -> elim_format, ...);
  3282 
  3283 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3284 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3285 should have to change intro!! to intro? only); replaced "delrule" by
  3286 "rule del";
  3287 
  3288 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3289 
  3290 * Provers: strengthened force_tac by using new first_best_tac;
  3291 
  3292 * LaTeX document preparation: several changes of isabelle.sty (see
  3293 lib/texinputs);
  3294 
  3295 
  3296 *** Document preparation ***
  3297 
  3298 * formal comments (text blocks etc.) in new-style theories may now
  3299 contain antiquotations of thm/prop/term/typ/text to be presented
  3300 according to latex print mode; concrete syntax is like this:
  3301 @{term[show_types] "f(x) = a + x"};
  3302 
  3303 * isatool mkdir provides easy setup of Isabelle session directories,
  3304 including proper document sources;
  3305 
  3306 * generated LaTeX sources are now deleted after successful run
  3307 (isatool document -c); may retain a copy somewhere else via -D option
  3308 of isatool usedir;
  3309 
  3310 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3311 style files, achieving self-contained LaTeX sources and simplifying
  3312 LaTeX debugging;
  3313 
  3314 * old-style theories now produce (crude) LaTeX output as well;
  3315 
  3316 * browser info session directories are now self-contained (may be put
  3317 on WWW server seperately); improved graphs of nested sessions; removed
  3318 graph for 'all sessions';
  3319 
  3320 * several improvements in isabelle style files; \isabellestyle{it}
  3321 produces fake math mode output; \isamarkupheader is now \section by
  3322 default; see lib/texinputs/isabelle.sty etc.;
  3323 
  3324 
  3325 *** Isar ***
  3326 
  3327 * Isar/Pure: local results and corresponding term bindings are now
  3328 subject to Hindley-Milner polymorphism (similar to ML); this
  3329 accommodates incremental type-inference very nicely;
  3330 
  3331 * Isar/Pure: new derived language element 'obtain' supports
  3332 generalized existence reasoning;
  3333 
  3334 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3335 support accumulation of results, without applying any rules yet;
  3336 useful to collect intermediate results without explicit name
  3337 references, and for use with transitivity rules with more than 2
  3338 premises;
  3339 
  3340 * Isar/Pure: scalable support for case-analysis type proofs: new
  3341 'case' language element refers to local contexts symbolically, as
  3342 produced by certain proof methods; internally, case names are attached
  3343 to theorems as "tags";
  3344 
  3345 * Isar/Pure: theory command 'hide' removes declarations from
  3346 class/type/const name spaces;
  3347 
  3348 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3349 indicate potential overloading;
  3350 
  3351 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3352 
  3353 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3354 "{a,b,c}" instead of {a,b,c};
  3355 
  3356 * Isar/Pure now provides its own version of intro/elim/dest
  3357 attributes; useful for building new logics, but beware of confusion
  3358 with the version in Provers/classical;
  3359 
  3360 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3361 case name 'antecedent';
  3362 
  3363 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3364 to the current context is now done automatically);
  3365 
  3366 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3367 for definining proof methods in ML;
  3368 
  3369 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3370 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3371 most cases, one should have to change intro!! to intro? only);
  3372 replaced "delrule" by "rule del";
  3373 
  3374 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3375 'symmetric' attribute (the latter supercedes [RS sym]);
  3376 
  3377 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3378 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3379 well (including splits);
  3380 
  3381 * Isar/Provers: Simplifier and Classical methods now support all kind
  3382 of modifiers used in the past, including 'cong', 'iff', etc.
  3383 
  3384 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3385 of Simplifier and Classical reasoner);
  3386 
  3387 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3388 now support named cases; major packages (inductive, datatype, primrec,
  3389 recdef) support case names and properly name parameters;
  3390 
  3391 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3392 monotonicity conditions are extracted to be proven at end of
  3393 calculations;
  3394 
  3395 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3396 method anyway;
  3397 
  3398 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3399 split_if split_if_asm; datatype package provides theorems foo.splits =
  3400 foo.split foo.split_asm for each datatype;
  3401 
  3402 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3403 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3404 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3405 use "(cases (simplified))" method in proper proof texts);
  3406 
  3407 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3408 
  3409 * Isar: names of theorems etc. may be natural numbers as well;
  3410 
  3411 * Isar: 'pr' command: optional arguments for goals_limit and
  3412 ProofContext.prems_limit; no longer prints theory contexts, but only
  3413 proof states;
  3414 
  3415 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3416 additional print modes to be specified; e.g. "pr(latex)" will print
  3417 proof state according to the Isabelle LaTeX style;
  3418 
  3419 * Isar: improved support for emulating tactic scripts, including proof
  3420 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3421 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3422 (for HOL datatypes);
  3423 
  3424 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3425 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3426 'proof method scripts' have to be in depth-first order;
  3427 
  3428 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3429 
  3430 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3431 should instead use individual commands for printing items
  3432 (print_commands, print_methods etc.);
  3433 
  3434 * Isar: added 'nothing' --- the empty list of theorems;
  3435 
  3436 
  3437 *** HOL ***
  3438 
  3439 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3440 corresponding virtual machine and a specification of its bytecode
  3441 verifier and a lightweight bytecode verifier, including proofs of
  3442 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3443 Cornelia Pusch (see also the homepage of project Bali at
  3444 http://isabelle.in.tum.de/Bali/);
  3445 
  3446 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3447 Clemens Ballarin;
  3448 
  3449 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3450 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3451 Rasmussen;
  3452 
  3453 * HOL/Lattice: fundamental concepts of lattice theory and order
  3454 structures, including duals, properties of bounds versus algebraic
  3455 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3456 Theorem for complete lattices etc.; may also serve as a demonstration
  3457 for abstract algebraic reasoning using axiomatic type classes, and
  3458 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3459 
  3460 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3461 von Oheimb;
  3462 
  3463 * HOL/IMPP: extension of IMP with local variables and mutually
  3464 recursive procedures, by David von Oheimb;
  3465 
  3466 * HOL/Lambda: converted into new-style theory and document;
  3467 
  3468 * HOL/ex/Multiquote: example of multiple nested quotations and
  3469 anti-quotations -- basically a generalized version of de-Bruijn
  3470 representation; very useful in avoiding lifting of operations;
  3471 
  3472 * HOL/record: added general record equality rule to simpset; fixed
  3473 select-update simplification procedure to handle extended records as
  3474 well; admit "r" as field name;
  3475 
  3476 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3477 other numeric types and also as the identity of groups, rings, etc.;
  3478 
  3479 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3480 Types nat and int belong to this axclass;
  3481 
  3482 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3483    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3484    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3485   two terms #m*u and #n*u are replaced by #(m+n)*u
  3486     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3487   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3488     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3489 
  3490 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3491 powerful prover for predicate logic but knows nothing of clasets; see
  3492 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3493 
  3494 * HOL: new version of "case_tac" subsumes both boolean case split and
  3495 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3496 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3497 
  3498 * HOL: simplification no longer dives into case-expressions: only the
  3499 selector expression is simplified, but not the remaining arms; to
  3500 enable full simplification of case-expressions for datatype t, you may
  3501 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3502 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3503 
  3504 * HOL/recdef: the recursion equations generated by 'recdef' for
  3505 function 'f' are now called f.simps instead of f.rules; if all
  3506 termination conditions are proved automatically, these simplification
  3507 rules are added to the simpset, as in primrec; rules may be named
  3508 individually as well, resulting in a separate list of theorems for
  3509 each equation;
  3510 
  3511 * HOL/While is a new theory that provides a while-combinator. It
  3512 permits the definition of tail-recursive functions without the
  3513 provision of a termination measure. The latter is necessary once the
  3514 invariant proof rule for while is applied.
  3515 
  3516 * HOL: new (overloaded) notation for the set of elements below/above
  3517 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3518 
  3519 * HOL: theorems impI, allI, ballI bound as "strip";
  3520 
  3521 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3522 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3523 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3524 
  3525 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3526 
  3527 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3528 main HOL, but was unused);
  3529 
  3530 * HOL: fewer consts declared as global (e.g. have to refer to
  3531 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3532 
  3533 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3534 in case of overlap with user translations (e.g. judgements over
  3535 tuples); (note that the underlying logical represenation is still
  3536 bogus);
  3537 
  3538 
  3539 *** ZF ***
  3540 
  3541 * ZF: simplification automatically cancels common terms in arithmetic
  3542 expressions over nat and int;
  3543 
  3544 * ZF: new treatment of nat to minimize type-checking: all operators
  3545 coerce their operands to a natural number using the function natify,
  3546 making the algebraic laws unconditional;
  3547 
  3548 * ZF: as above, for int: operators coerce their operands to an integer
  3549 using the function intify;
  3550 
  3551 * ZF: the integer library now contains many of the usual laws for the
  3552 orderings, including $<=, and monotonicity laws for $+ and $*;
  3553 
  3554 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3555 simplification;
  3556 
  3557 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3558 to the simplifier and classical reasoner simultaneously;
  3559 
  3560 
  3561 *** General ***
  3562 
  3563 * Provers: blast_tac now handles actual object-logic rules as
  3564 assumptions; note that auto_tac uses blast_tac internally as well;
  3565 
  3566 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3567 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3568 
  3569 * Provers: delrules now handles destruct rules as well (no longer need
  3570 explicit make_elim);
  3571 
  3572 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3573   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3574 use instead the strong form,
  3575   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3576 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3577 from destruct-rules;
  3578 
  3579 * Provers: Simplifier.easy_setup provides a fast path to basic
  3580 Simplifier setup for new object-logics;
  3581 
  3582 * Pure: AST translation rules no longer require constant head on LHS;
  3583 
  3584 * Pure: improved name spaces: ambiguous output is qualified; support
  3585 for hiding of names;
  3586 
  3587 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3588 XSYMBOL_HOME; no longer need to do manual configuration in most
  3589 situations;
  3590 
  3591 * system: compression of ML heaps images may now be controlled via -c
  3592 option of isabelle and isatool usedir (currently only observed by
  3593 Poly/ML);
  3594 
  3595 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3596 useful for remote X11);
  3597 
  3598 * system: provide TAGS file for Isabelle sources;
  3599 
  3600 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3601 order;
  3602 
  3603 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3604 timing flag supersedes proof_timing and Toplevel.trace;
  3605 
  3606 * ML: new combinators |>> and |>>> for incremental transformations
  3607 with secondary results (e.g. certain theory extensions):
  3608 
  3609 * ML: PureThy.add_defs gets additional argument to indicate potential
  3610 overloading (usually false);
  3611 
  3612 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3613 results;
  3614 
  3615 
  3616 
  3617 New in Isabelle99 (October 1999)
  3618 --------------------------------
  3619 
  3620 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3621 
  3622 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3623 are no longer simplified.  (This allows the simplifier to unfold recursive
  3624 functional programs.)  To restore the old behaviour, declare
  3625 
  3626     Delcongs [if_weak_cong];
  3627 
  3628 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3629 complement;
  3630 
  3631 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3632 
  3633 * HOL/datatype: mutual_induct_tac no longer exists --
  3634   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3635 
  3636 * HOL/typedef: fixed type inference for representing set; type
  3637 arguments now have to occur explicitly on the rhs as type constraints;
  3638 
  3639 * ZF: The con_defs part of an inductive definition may no longer refer
  3640 to constants declared in the same theory;
  3641 
  3642 * HOL, ZF: the function mk_cases, generated by the inductive
  3643 definition package, has lost an argument.  To simplify its result, it
  3644 uses the default simpset instead of a supplied list of theorems.
  3645 
  3646 * HOL/List: the constructors of type list are now Nil and Cons;
  3647 
  3648 * Simplifier: the type of the infix ML functions
  3649         setSSolver addSSolver setSolver addSolver
  3650 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3651 for packaging solvers. A solver is created via
  3652         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3653 where the string argument is only a comment.
  3654 
  3655 
  3656 *** Proof tools ***
  3657 
  3658 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3659 decision procedure for linear arithmetic. Currently it is used for
  3660 types `nat', `int', and `real' in HOL (see below); it can, should and
  3661 will be instantiated for other types and logics as well.
  3662 
  3663 * The simplifier now accepts rewrite rules with flexible heads, eg
  3664      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3665   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3666   matching.
  3667 
  3668 
  3669 *** General ***
  3670 
  3671 * New Isabelle/Isar subsystem provides an alternative to traditional
  3672 tactical theorem proving; together with the ProofGeneral/isar user
  3673 interface it offers an interactive environment for developing human
  3674 readable proof documents (Isar == Intelligible semi-automated
  3675 reasoning); for further information see isatool doc isar-ref,
  3676 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3677 
  3678 * improved and simplified presentation of theories: better HTML markup
  3679 (including colors), graph views in several sizes; isatool usedir now
  3680 provides a proper interface for user theories (via -P option); actual
  3681 document preparation based on (PDF)LaTeX is available as well (for
  3682 new-style theories only); see isatool doc system for more information;
  3683 
  3684 * native support for Proof General, both for classic Isabelle and
  3685 Isabelle/Isar;
  3686 
  3687 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3688 using the graph browser tool;
  3689 
  3690 * Isabelle manuals now also available as PDF;
  3691 
  3692 * theory loader rewritten from scratch (may not be fully
  3693 bug-compatible); old loadpath variable has been replaced by show_path,
  3694 add_path, del_path, reset_path functions; new operations such as
  3695 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3696 isatool doc ref);
  3697 
  3698 * improved isatool install: option -k creates KDE application icon,
  3699 option -p DIR installs standalone binaries;
  3700 
  3701 * added ML_PLATFORM setting (useful for cross-platform installations);
  3702 more robust handling of platform specific ML images for SML/NJ;
  3703 
  3704 * the settings environment is now statically scoped, i.e. it is never
  3705 created again in sub-processes invoked from isabelle, isatool, or
  3706 Isabelle;
  3707 
  3708 * path element specification '~~' refers to '$ISABELLE_HOME';
  3709 
  3710 * in locales, the "assumes" and "defines" parts may be omitted if
  3711 empty;
  3712 
  3713 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3714 long arrows);
  3715 
  3716 * new print_mode "HTML";
  3717 
  3718 * new flag show_tags controls display of tags of theorems (which are
  3719 basically just comments that may be attached by some tools);
  3720 
  3721 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3722 mode and goal output format:
  3723 
  3724 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3725 244c244
  3726 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3727 ---
  3728 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3729 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3730 181c181
  3731 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3732 ---
  3733 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3734 
  3735 * function bind_thms stores lists of theorems (cf. bind_thm);
  3736 
  3737 * new shorthand tactics ftac, eatac, datac, fatac;
  3738 
  3739 * qed (and friends) now accept "" as result name; in that case the
  3740 theorem is not stored, but proper checks and presentation of the
  3741 result still apply;
  3742 
  3743 * theorem database now also indexes constants "Trueprop", "all",
  3744 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3745 
  3746 
  3747 *** HOL ***
  3748 
  3749 ** HOL arithmetic **
  3750 
  3751 * There are now decision procedures for linear arithmetic over nat and
  3752 int:
  3753 
  3754 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3755 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3756 are treated as atomic; subformulae not involving type `nat' or `int'
  3757 are ignored; quantified subformulae are ignored unless they are
  3758 positive universal or negative existential. The tactic has to be
  3759 invoked by hand and can be a little bit slow. In particular, the
  3760 running time is exponential in the number of occurrences of `min' and
  3761 `max', and `-' on `nat'.
  3762 
  3763 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3764 (negated) (in)equalities among the premises and the conclusion into
  3765 account (i.e. no compound formulae) and does not know about `min' and
  3766 `max', and `-' on `nat'. It is fast and is used automatically by the
  3767 simplifier.
  3768 
  3769 NB: At the moment, these decision procedures do not cope with mixed
  3770 nat/int formulae where the two parts interact, such as `m < n ==>
  3771 int(m) < int(n)'.
  3772 
  3773 * HOL/Numeral provides a generic theory of numerals (encoded
  3774 efficiently as bit strings); setup for types nat/int/real is in place;
  3775 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3776 int, existing theories and proof scripts may require a few additional
  3777 type constraints;
  3778 
  3779 * integer division and remainder can now be performed on constant
  3780 arguments;
  3781 
  3782 * many properties of integer multiplication, division and remainder
  3783 are now available;
  3784 
  3785 * An interface to the Stanford Validity Checker (SVC) is available through the
  3786 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3787 are proved automatically.  SVC must be installed separately, and its results
  3788 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3789 invocation of the underlying oracle).  For SVC see
  3790   http://verify.stanford.edu/SVC
  3791 
  3792 * IsaMakefile: the HOL-Real target now builds an actual image;
  3793 
  3794 
  3795 ** HOL misc **
  3796 
  3797 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3798 (in Isabelle/Isar) -- by Gertrud Bauer;
  3799 
  3800 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3801 analysis for assembly languages with subtypes;
  3802 
  3803 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3804 -- avoids syntactic ambiguities and treats state, transition, and
  3805 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3806 changed syntax and (many) tactics;
  3807 
  3808 * HOL/inductive: Now also handles more general introduction rules such
  3809   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3810   theorems are now maintained within the theory (maintained via the
  3811   "mono" attribute);
  3812 
  3813 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3814   (using function types) such as
  3815 
  3816   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3817 
  3818 * HOL/record: record_simproc (part of the default simpset) takes care
  3819 of selectors applied to updated records; record_split_tac is no longer
  3820 part of the default claset; update_defs may now be removed from the
  3821 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3822 
  3823   claset_ref () := claset() addSWrapper record_split_wrapper;
  3824   Delsimprocs [record_simproc]
  3825 
  3826 * HOL/typedef: fixed type inference for representing set; type
  3827 arguments now have to occur explicitly on the rhs as type constraints;
  3828 
  3829 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3830 names rather than an ML expression;
  3831 
  3832 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3833 supplied later.  Program schemes can be defined, such as
  3834     "While B C s = (if B s then While B C (C s) else s)"
  3835 where the well-founded relation can be chosen after B and C have been given.
  3836 
  3837 * HOL/List: the constructors of type list are now Nil and Cons;
  3838 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3839 course, ML tools referring to List.list.op # etc. have to be adapted;
  3840 
  3841 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3842 disabled by default; run isabelle with option -m HOL to get back to
  3843 the original Gordon/HOL-style output;
  3844 
  3845 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3846 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3847 
  3848 * HOL basic syntax simplified (more orthogonal): all variants of
  3849 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3850 Eps operator is provided as well: "SOME x. P[x]";
  3851 
  3852 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3853 
  3854 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3855 thus available for user theories;
  3856 
  3857 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3858 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3859 time;
  3860 
  3861 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3862 several times and then mp;
  3863 
  3864 
  3865 *** LK ***
  3866 
  3867 * the notation <<...>> is now available as a notation for sequences of
  3868 formulas;
  3869 
  3870 * the simplifier is now installed
  3871 
  3872 * the axiom system has been generalized (thanks to Soren Heilmann)
  3873 
  3874 * the classical reasoner now has a default rule database
  3875 
  3876 
  3877 *** ZF ***
  3878 
  3879 * new primrec section allows primitive recursive functions to be given
  3880 directly (as in HOL) over datatypes and the natural numbers;
  3881 
  3882 * new tactics induct_tac and exhaust_tac for induction (or case
  3883 analysis) over datatypes and the natural numbers;
  3884 
  3885 * the datatype declaration of type T now defines the recursor T_rec;
  3886 
  3887 * simplification automatically does freeness reasoning for datatype
  3888 constructors;
  3889 
  3890 * automatic type-inference, with AddTCs command to insert new
  3891 type-checking rules;
  3892 
  3893 * datatype introduction rules are now added as Safe Introduction rules
  3894 to the claset;
  3895 
  3896 * the syntax "if P then x else y" is now available in addition to
  3897 if(P,x,y);
  3898 
  3899 
  3900 *** Internal programming interfaces ***
  3901 
  3902 * tuned simplifier trace output; new flag debug_simp;
  3903 
  3904 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3905 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3906 
  3907 * AxClass.axclass_tac lost the theory argument;
  3908 
  3909 * tuned current_goals_markers semantics: begin / end goal avoids
  3910 printing empty lines;
  3911 
  3912 * removed prs and prs_fn hook, which was broken because it did not
  3913 include \n in its semantics, forcing writeln to add one
  3914 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3915 string -> unit if you really want to output text without newline;
  3916 
  3917 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3918 plain output, interface builders may have to enable 'isabelle_font'
  3919 mode to get Isabelle font glyphs as before;
  3920 
  3921 * refined token_translation interface; INCOMPATIBILITY: output length
  3922 now of type real instead of int;
  3923 
  3924 * theory loader actions may be traced via new ThyInfo.add_hook
  3925 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3926 your own database of information attached to *whole* theories -- as
  3927 opposed to intra-theory data slots offered via TheoryDataFun;
  3928 
  3929 * proper handling of dangling sort hypotheses (at last!);
  3930 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3931 extra sort hypotheses that can be witnessed from the type signature;
  3932 the force_strip_shyps flag is gone, any remaining shyps are simply
  3933 left in the theorem (with a warning issued by strip_shyps_warning);
  3934 
  3935 
  3936 
  3937 New in Isabelle98-1 (October 1998)
  3938 ----------------------------------
  3939 
  3940 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3941 
  3942 * several changes of automated proof tools;
  3943 
  3944 * HOL: major changes to the inductive and datatype packages, including
  3945 some minor incompatibilities of theory syntax;
  3946 
  3947 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3948 called `inj_on';
  3949 
  3950 * HOL: removed duplicate thms in Arith:
  3951   less_imp_add_less  should be replaced by  trans_less_add1
  3952   le_imp_add_le      should be replaced by  trans_le_add1
  3953 
  3954 * HOL: unary minus is now overloaded (new type constraints may be
  3955 required);
  3956 
  3957 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3958 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3959 now taken as an integer constant.
  3960 
  3961 * Pure: ML function 'theory_of' renamed to 'theory';
  3962 
  3963 
  3964 *** Proof tools ***
  3965 
  3966 * Simplifier:
  3967   1. Asm_full_simp_tac is now more aggressive.
  3968      1. It will sometimes reorient premises if that increases their power to
  3969         simplify.
  3970      2. It does no longer proceed strictly from left to right but may also
  3971         rotate premises to achieve further simplification.
  3972      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3973      old Asm_full_simp_tac in that it does not rotate premises.
  3974   2. The simplifier now knows a little bit about nat-arithmetic.
  3975 
  3976 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3977 allows for selected deletion of wrappers, by introduction of names for
  3978 wrapper functionals.  This implies that addbefore, addSbefore,
  3979 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3980 and that adding two tactics with the same name overwrites the first
  3981 one (emitting a warning).
  3982   type wrapper = (int -> tactic) -> (int -> tactic)
  3983   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3984   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3985   delWrapper, delSWrapper: claset *  string            -> claset
  3986   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3987 
  3988 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3989 semantics; addbefore now affects only the unsafe part of step_tac
  3990 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3991 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3992 by Force_tac;
  3993 
  3994 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3995 compWrapper; added safe wrapper (and access functions for it);
  3996 
  3997 * HOL/split_all_tac is now much faster and fails if there is nothing
  3998 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3999 and the names of the automatically generated variables have changed.
  4000 split_all_tac has moved within claset() from unsafe wrappers to safe
  4001 wrappers, which means that !!-bound variables are split much more
  4002 aggressively, and safe_tac and clarify_tac now split such variables.
  4003 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4004 Note: the same holds for record_split_tac, which does the job of
  4005 split_all_tac for record fields.
  4006 
  4007 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4008 permanently to the default simpset using Addsplits just like
  4009 Addsimps. They can be removed via Delsplits just like
  4010 Delsimps. Lower-case versions are also available.
  4011 
  4012 * HOL/Simplifier: The rule split_if is now part of the default
  4013 simpset. This means that the simplifier will eliminate all occurrences
  4014 of if-then-else in the conclusion of a goal. To prevent this, you can
  4015 either remove split_if completely from the default simpset by
  4016 `Delsplits [split_if]' or remove it in a specific call of the
  4017 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4018 other case splitting rules to/from the default simpset: every datatype
  4019 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4020 t is the name of the datatype).
  4021 
  4022 * Classical reasoner / Simplifier combination: new force_tac (and
  4023 derivatives Force_tac, force) combines rewriting and classical
  4024 reasoning (and whatever other tools) similarly to auto_tac, but is
  4025 aimed to solve the given subgoal completely.
  4026 
  4027 
  4028 *** General ***
  4029 
  4030 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4031 and `goalw': the theory is no longer needed as an explicit argument -
  4032 the current theory context is used; assumptions are no longer returned
  4033 at the ML-level unless one of them starts with ==> or !!; it is
  4034 recommended to convert to these new commands using isatool fixgoal
  4035 (backup your sources first!);
  4036 
  4037 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4038 the current theory context, and 'theory' to lookup stored theories;
  4039 
  4040 * new theory section 'locale' for declaring constants, assumptions and
  4041 definitions that have local scope;
  4042 
  4043 * new theory section 'nonterminals' for purely syntactic types;
  4044 
  4045 * new theory section 'setup' for generic ML setup functions
  4046 (e.g. package initialization);
  4047 
  4048 * the distribution now includes Isabelle icons: see
  4049 lib/logo/isabelle-{small,tiny}.xpm;
  4050 
  4051 * isatool install - install binaries with absolute references to
  4052 ISABELLE_HOME/bin;
  4053 
  4054 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4055 
  4056 * print mode 'emacs' reserved for Isamode;
  4057 
  4058 * support multiple print (ast) translations per constant name;
  4059 
  4060 * theorems involving oracles are now printed with a suffixed [!];
  4061 
  4062 
  4063 *** HOL ***
  4064 
  4065 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4066 
  4067 * HOL/inductive package reorganized and improved: now supports mutual
  4068 definitions such as
  4069 
  4070   inductive EVEN ODD
  4071     intrs
  4072       null "0 : EVEN"
  4073       oddI "n : EVEN ==> Suc n : ODD"
  4074       evenI "n : ODD ==> Suc n : EVEN"
  4075 
  4076 new theorem list "elims" contains an elimination rule for each of the
  4077 recursive sets; inductive definitions now handle disjunctive premises
  4078 correctly (also ZF);
  4079 
  4080 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4081 "mutual_induct" no longer exists - the induction rule is always
  4082 contained in "induct";
  4083 
  4084 
  4085 * HOL/datatype package re-implemented and greatly improved: now
  4086 supports mutually recursive datatypes such as
  4087 
  4088   datatype
  4089     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4090             | SUM ('a aexp) ('a aexp)
  4091             | DIFF ('a aexp) ('a aexp)
  4092             | NUM 'a
  4093   and
  4094     'a bexp = LESS ('a aexp) ('a aexp)
  4095             | AND ('a bexp) ('a bexp)
  4096             | OR ('a bexp) ('a bexp)
  4097 
  4098 as well as indirectly recursive datatypes such as
  4099 
  4100   datatype
  4101     ('a, 'b) term = Var 'a
  4102                   | App 'b ((('a, 'b) term) list)
  4103 
  4104 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4105 induction on mutually / indirectly recursive datatypes.
  4106 
  4107 Primrec equations are now stored in theory and can be accessed via
  4108 <function_name>.simps.
  4109 
  4110 INCOMPATIBILITIES:
  4111 
  4112   - Theories using datatypes must now have theory Datatype as an
  4113     ancestor.
  4114   - The specific <typename>.induct_tac no longer exists - use the
  4115     generic induct_tac instead.
  4116   - natE has been renamed to nat.exhaust - use exhaust_tac
  4117     instead of res_inst_tac ... natE. Note that the variable
  4118     names in nat.exhaust differ from the names in natE, this
  4119     may cause some "fragile" proofs to fail.
  4120   - The theorems split_<typename>_case and split_<typename>_case_asm
  4121     have been renamed to <typename>.split and <typename>.split_asm.
  4122   - Since default sorts of type variables are now handled correctly,
  4123     some datatype definitions may have to be annotated with explicit
  4124     sort constraints.
  4125   - Primrec definitions no longer require function name and type
  4126     of recursive argument.
  4127 
  4128 Consider using isatool fixdatatype to adapt your theories and proof
  4129 scripts to the new package (backup your sources first!).
  4130 
  4131 
  4132 * HOL/record package: considerably improved implementation; now
  4133 includes concrete syntax for record types, terms, updates; theorems
  4134 for surjective pairing and splitting !!-bound record variables; proof
  4135 support is as follows:
  4136 
  4137   1) standard conversions (selectors or updates applied to record
  4138 constructor terms) are part of the standard simpset;
  4139 
  4140   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4141 made part of standard simpset and claset via addIffs;
  4142 
  4143   3) a tactic for record field splitting (record_split_tac) is part of
  4144 the standard claset (addSWrapper);
  4145 
  4146 To get a better idea about these rules you may retrieve them via
  4147 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4148 the name of your record type.
  4149 
  4150 The split tactic 3) conceptually simplifies by the following rule:
  4151 
  4152   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4153 
  4154 Thus any record variable that is bound by meta-all will automatically
  4155 blow up into some record constructor term, consequently the
  4156 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4157 solve record problems automatically.
  4158 
  4159 
  4160 * reorganized the main HOL image: HOL/Integ and String loaded by
  4161 default; theory Main includes everything;
  4162 
  4163 * automatic simplification of integer sums and comparisons, using cancellation;
  4164 
  4165 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4166 
  4167 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4168 
  4169 * many new identities for unions, intersections, set difference, etc.;
  4170 
  4171 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4172 called split_if, split_split, split_sum_case and split_nat_case (to go
  4173 with add/delsplits);
  4174 
  4175 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4176 (?x::unit) = (); this is made part of the default simpset, which COULD
  4177 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4178 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4179 unit_abs_eta_conv is added in order to counter the effect of
  4180 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4181 %u.f();
  4182 
  4183 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4184 makes more sense);
  4185 
  4186 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4187   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4188   disjointness reasoning but breaking a few old proofs.
  4189 
  4190 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4191 to 'converse' from 'inverse' (for compatibility with ZF and some
  4192 literature);
  4193 
  4194 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4195 the well-founded relation;
  4196 
  4197 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4198     Compl A.  The "Compl" syntax remains available as input syntax for this
  4199     release ONLY.
  4200 
  4201 * HOL/Update: new theory of function updates:
  4202     f(a:=b) == %x. if x=a then b else f x
  4203 may also be iterated as in f(a:=b,c:=d,...);
  4204 
  4205 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4206 
  4207 * HOL/List:
  4208   - new function list_update written xs[i:=v] that updates the i-th
  4209     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4210   - new function `upt' written [i..j(] which generates the list
  4211     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4212     bound write [i..j], which is a shorthand for [i..j+1(].
  4213   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4214 
  4215 * HOL/Arith:
  4216   - removed 'pred' (predecessor) function;
  4217   - generalized some theorems about n-1;
  4218   - many new laws about "div" and "mod";
  4219   - new laws about greatest common divisors (see theory ex/Primes);
  4220 
  4221 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4222 instead of "inverse";
  4223 
  4224 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4225   of the multiset ordering;
  4226 
  4227 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4228   (not included by default);
  4229 
  4230 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4231 
  4232 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4233   programs, i.e. different program variables may have different types.
  4234 
  4235 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4236   [previously, this check worked only if the rewrite rule was unconditional]
  4237   Now rew can involve either definitions or equalities (either == or =).
  4238 
  4239 
  4240 *** ZF ***
  4241 
  4242 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4243   only the theorems proved on ZF.ML;
  4244 
  4245 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4246   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4247   disjointness reasoning but breaking a few old proofs.
  4248 
  4249 * ZF/Update: new theory of function updates
  4250     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4251   may also be iterated as in f(a:=b,c:=d,...);
  4252 
  4253 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4254 
  4255 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4256   [previously, this check worked only if the rewrite rule was unconditional]
  4257   Now rew can involve either definitions or equalities (either == or =).
  4258 
  4259 * case_tac provided for compatibility with HOL
  4260     (like the old excluded_middle_tac, but with subgoals swapped)
  4261 
  4262 
  4263 *** Internal programming interfaces ***
  4264 
  4265 * Pure: several new basic modules made available for general use, see
  4266 also src/Pure/README;
  4267 
  4268 * improved the theory data mechanism to support encapsulation (data
  4269 kind name replaced by private Object.kind, acting as authorization
  4270 key); new type-safe user interface via functor TheoryDataFun; generic
  4271 print_data function becomes basically useless;
  4272 
  4273 * removed global_names compatibility flag -- all theory declarations
  4274 are qualified by default;
  4275 
  4276 * module Pure/Syntax now offers quote / antiquote translation
  4277 functions (useful for Hoare logic etc. with implicit dependencies);
  4278 see HOL/ex/Antiquote for an example use;
  4279 
  4280 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4281 cterm -> thm;
  4282 
  4283 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4284 subgoal;
  4285 
  4286 * Display.print_goals function moved to Locale.print_goals;
  4287 
  4288 * standard print function for goals supports current_goals_markers
  4289 variable for marking begin of proof, end of proof, start of goal; the
  4290 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4291 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4292 for example;
  4293 
  4294 
  4295 
  4296 New in Isabelle98 (January 1998)
  4297 --------------------------------
  4298 
  4299 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4300 
  4301 * changed lexical syntax of terms / types: dots made part of long
  4302 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4303 
  4304 * simpset (and claset) reference variable replaced by functions
  4305 simpset / simpset_ref;
  4306 
  4307 * no longer supports theory aliases (via merge) and non-trivial
  4308 implicit merge of thms' signatures;
  4309 
  4310 * most internal names of constants changed due to qualified names;
  4311 
  4312 * changed Pure/Sequence interface (see Pure/seq.ML);
  4313 
  4314 
  4315 *** General Changes ***
  4316 
  4317 * hierachically structured name spaces (for consts, types, axms, thms
  4318 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4319 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4320 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4321 long_names for fully qualified output names; NOTE: ML programs
  4322 (special tactics, packages etc.) referring to internal names may have
  4323 to be adapted to cope with fully qualified names; in case of severe
  4324 backward campatibility problems try setting 'global_names' at compile
  4325 time to have enrything declared within a flat name space; one may also
  4326 fine tune name declarations in theories via the 'global' and 'local'
  4327 section;
  4328 
  4329 * reimplemented the implicit simpset and claset using the new anytype
  4330 data filed in signatures; references simpset:simpset ref etc. are
  4331 replaced by functions simpset:unit->simpset and
  4332 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4333 to patch your ML files accordingly;
  4334 
  4335 * HTML output now includes theory graph data for display with Java
  4336 applet or isatool browser; data generated automatically via isatool
  4337 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4338 
  4339 * defs may now be conditional; improved rewrite_goals_tac to handle
  4340 conditional equations;
  4341 
  4342 * defs now admits additional type arguments, using TYPE('a) syntax;
  4343 
  4344 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4345 creates a new theory node; implicit merge of thms' signatures is
  4346 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4347 transfer:theory->thm->thm in (rare) cases;
  4348 
  4349 * improved handling of draft signatures / theories; draft thms (and
  4350 ctyps, cterms) are automatically promoted to real ones;
  4351 
  4352 * slightly changed interfaces for oracles: admit many per theory, named
  4353 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4354 
  4355 * print_goals: optional output of const types (set show_consts and
  4356 show_types);
  4357 
  4358 * improved output of warnings (###) and errors (***);
  4359 
  4360 * subgoal_tac displays a warning if the new subgoal has type variables;
  4361 
  4362 * removed old README and Makefiles;
  4363 
  4364 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4365 
  4366 * removed obsolete init_pps and init_database;
  4367 
  4368 * deleted the obsolete tactical STATE, which was declared by
  4369     fun STATE tacfun st = tacfun st st;
  4370 
  4371 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4372 (which abbreviates $HOME);
  4373 
  4374 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4375 use isatool fixseq to adapt your ML programs (this works for fully
  4376 qualified references to the Sequence structure only!);
  4377 
  4378 * use_thy no longer requires writable current directory; it always
  4379 reloads .ML *and* .thy file, if either one is out of date;
  4380 
  4381 
  4382 *** Classical Reasoner ***
  4383 
  4384 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4385 tactics that use classical reasoning to simplify a subgoal without
  4386 splitting it into several subgoals;
  4387 
  4388 * Safe_tac: like safe_tac but uses the default claset;
  4389 
  4390 
  4391 *** Simplifier ***
  4392 
  4393 * added simplification meta rules:
  4394     (asm_)(full_)simplify: simpset -> thm -> thm;
  4395 
  4396 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4397 logics (again);
  4398 
  4399 * added prems argument to simplification procedures;
  4400 
  4401 * HOL, FOL, ZF: added infix function `addsplits':
  4402   instead of `<simpset> setloop (split_tac <thms>)'
  4403   you can simply write `<simpset> addsplits <thms>'
  4404 
  4405 
  4406 *** Syntax ***
  4407 
  4408 * TYPE('a) syntax for type reflection terms;
  4409 
  4410 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4411 
  4412 * pretty printer: changed order of mixfix annotation preference (again!);
  4413 
  4414 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4415 
  4416 
  4417 *** HOL ***
  4418 
  4419 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4420   with `addloop' of the simplifier to faciliate case splitting in premises.
  4421 
  4422 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4423 
  4424 * HOL/Auth: new protocol proofs including some for the Internet
  4425   protocol TLS;
  4426 
  4427 * HOL/Map: new theory of `maps' a la VDM;
  4428 
  4429 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4430 cancelling out common nat summands from =, <, <= (in)equalities, or
  4431 differences; simplification procedures nat_cancel_factor for
  4432 cancelling common factor from =, <, <= (in)equalities over natural
  4433 sums; nat_cancel contains both kinds of procedures, it is installed by
  4434 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4435 
  4436 * HOL/simplifier: terms of the form
  4437   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4438   are rewritten to
  4439   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4440   and those of the form
  4441   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4442   are rewritten to
  4443   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4444 
  4445 * HOL/datatype
  4446   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4447 
  4448   P(t_case f1 ... fn x) =
  4449      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4450         ...
  4451        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4452      )
  4453 
  4454   and a theorem `split_t_case_asm' of the form
  4455 
  4456   P(t_case f1 ... fn x) =
  4457     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4458         ...
  4459        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4460      )
  4461   which can be added to a simpset via `addsplits'. The existing theorems
  4462   expand_list_case and expand_option_case have been renamed to
  4463   split_list_case and split_option_case.
  4464 
  4465 * HOL/Arithmetic:
  4466   - `pred n' is automatically converted to `n-1'.
  4467     Users are strongly encouraged not to use `pred' any longer,
  4468     because it will disappear altogether at some point.
  4469   - Users are strongly encouraged to write "0 < n" rather than
  4470     "n ~= 0". Theorems and proof tools have been modified towards this
  4471     `standard'.
  4472 
  4473 * HOL/Lists:
  4474   the function "set_of_list" has been renamed "set" (and its theorems too);
  4475   the function "nth" now takes its arguments in the reverse order and
  4476   has acquired the infix notation "!" as in "xs!n".
  4477 
  4478 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4479 
  4480 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4481   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4482 
  4483 * HOL/record: extensible records with schematic structural subtyping
  4484 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4485 still lacks various theorems and concrete record syntax;
  4486 
  4487 
  4488 *** HOLCF ***
  4489 
  4490 * removed "axioms" and "generated by" sections;
  4491 
  4492 * replaced "ops" section by extended "consts" section, which is capable of
  4493   handling the continuous function space "->" directly;
  4494 
  4495 * domain package:
  4496   . proves theorems immediately and stores them in the theory,
  4497   . creates hierachical name space,
  4498   . now uses normal mixfix annotations (instead of cinfix...),
  4499   . minor changes to some names and values (for consistency),
  4500   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4501   . separator between mutual domain defs: changed "," to "and",
  4502   . improved handling of sort constraints;  now they have to
  4503     appear on the left-hand side of the equations only;
  4504 
  4505 * fixed LAM <x,y,zs>.b syntax;
  4506 
  4507 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4508 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4509 
  4510 
  4511 *** FOL and ZF ***
  4512 
  4513 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4514   with `addloop' of the simplifier to faciliate case splitting in premises.
  4515 
  4516 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4517 in HOL, they strip ALL and --> from proved theorems;
  4518 
  4519 
  4520 
  4521 New in Isabelle94-8 (May 1997)
  4522 ------------------------------
  4523 
  4524 *** General Changes ***
  4525 
  4526 * new utilities to build / run / maintain Isabelle etc. (in parts
  4527 still somewhat experimental); old Makefiles etc. still functional;
  4528 
  4529 * new 'Isabelle System Manual';
  4530 
  4531 * INSTALL text, together with ./configure and ./build scripts;
  4532 
  4533 * reimplemented type inference for greater efficiency, better error
  4534 messages and clean internal interface;
  4535 
  4536 * prlim command for dealing with lots of subgoals (an easier way of
  4537 setting goals_limit);
  4538 
  4539 
  4540 *** Syntax ***
  4541 
  4542 * supports alternative (named) syntax tables (parser and pretty
  4543 printer); internal interface is provided by add_modesyntax(_i);
  4544 
  4545 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4546 be used in conjunction with the Isabelle symbol font; uses the
  4547 "symbols" syntax table;
  4548 
  4549 * added token_translation interface (may translate name tokens in
  4550 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4551 the current print_mode); IMPORTANT: user print translation functions
  4552 are responsible for marking newly introduced bounds
  4553 (Syntax.mark_boundT);
  4554 
  4555 * token translations for modes "xterm" and "xterm_color" that display
  4556 names in bold, underline etc. or colors (which requires a color
  4557 version of xterm);
  4558 
  4559 * infixes may now be declared with names independent of their syntax;
  4560 
  4561 * added typed_print_translation (like print_translation, but may
  4562 access type of constant);
  4563 
  4564 
  4565 *** Classical Reasoner ***
  4566 
  4567 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4568 some limitations.  Blast_tac...
  4569   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4570   + ignores elimination rules that don't have the correct format
  4571         (the conclusion MUST be a formula variable)
  4572   + ignores types, which can make HOL proofs fail
  4573   + rules must not require higher-order unification, e.g. apply_type in ZF
  4574     [message "Function Var's argument not a bound variable" relates to this]
  4575   + its proof strategy is more general but can actually be slower
  4576 
  4577 * substitution with equality assumptions no longer permutes other
  4578 assumptions;
  4579 
  4580 * minor changes in semantics of addafter (now called addaltern); renamed
  4581 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4582 (and access functions for it);
  4583 
  4584 * improved combination of classical reasoner and simplifier:
  4585   + functions for handling clasimpsets
  4586   + improvement of addss: now the simplifier is called _after_ the
  4587     safe steps.
  4588   + safe variant of addss called addSss: uses safe simplifications
  4589     _during_ the safe steps. It is more complete as it allows multiple
  4590     instantiations of unknowns (e.g. with slow_tac).
  4591 
  4592 *** Simplifier ***
  4593 
  4594 * added interface for simplification procedures (functions that
  4595 produce *proven* rewrite rules on the fly, depending on current
  4596 redex);
  4597 
  4598 * ordering on terms as parameter (used for ordered rewriting);
  4599 
  4600 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4601 
  4602 * the solver is now split into a safe and an unsafe part.
  4603 This should be invisible for the normal user, except that the
  4604 functions setsolver and addsolver have been renamed to setSolver and
  4605 addSolver; added safe_asm_full_simp_tac;
  4606 
  4607 
  4608 *** HOL ***
  4609 
  4610 * a generic induction tactic `induct_tac' which works for all datatypes and
  4611 also for type `nat';
  4612 
  4613 * a generic case distinction tactic `exhaust_tac' which works for all
  4614 datatypes and also for type `nat';
  4615 
  4616 * each datatype comes with a function `size';
  4617 
  4618 * patterns in case expressions allow tuple patterns as arguments to
  4619 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4620 
  4621 * primrec now also works with type nat;
  4622 
  4623 * recdef: a new declaration form, allows general recursive functions to be
  4624 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4625 
  4626 * the constant for negation has been renamed from "not" to "Not" to
  4627 harmonize with FOL, ZF, LK, etc.;
  4628 
  4629 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4630 infinite lists;
  4631 
  4632 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4633 
  4634 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4635 problems in commutative rings, using axiomatic type classes for + and *;
  4636 
  4637 * more examples in HOL/MiniML and HOL/Auth;
  4638 
  4639 * more default rewrite rules for quantifiers, union/intersection;
  4640 
  4641 * a new constant `arbitrary == @x.False';
  4642 
  4643 * HOLCF/IOA replaces old HOL/IOA;
  4644 
  4645 * HOLCF changes: derived all rules and arities
  4646   + axiomatic type classes instead of classes
  4647   + typedef instead of faking type definitions
  4648   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4649   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4650   + eliminated the types void, one, tr
  4651   + use unit lift and bool lift (with translations) instead of one and tr
  4652   + eliminated blift from Lift3.thy (use Def instead of blift)
  4653   all eliminated rules are derived as theorems --> no visible changes ;
  4654 
  4655 
  4656 *** ZF ***
  4657 
  4658 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4659 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4660 as ZF_cs addSIs [equalityI];
  4661 
  4662 
  4663 
  4664 New in Isabelle94-7 (November 96)
  4665 ---------------------------------
  4666 
  4667 * allowing negative levels (as offsets) in prlev and choplev;
  4668 
  4669 * super-linear speedup for large simplifications;
  4670 
  4671 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4672 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4673 FAIL); can suppress it using the command Delsimps (ex_simps @
  4674 all_simps); De Morgan laws are also now included, by default;
  4675 
  4676 * improved printing of ==>  :  ~:
  4677 
  4678 * new object-logic "Sequents" adds linear logic, while replacing LK
  4679 and Modal (thanks to Sara Kalvala);
  4680 
  4681 * HOL/Auth: correctness proofs for authentication protocols;
  4682 
  4683 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4684 examples on HOL/Auth);
  4685 
  4686 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4687 the rewriter and classical reasoner simultaneously;
  4688 
  4689 * function uresult no longer returns theorems in "standard" format;
  4690 regain previous version by: val uresult = standard o uresult;
  4691 
  4692 
  4693 
  4694 New in Isabelle94-6
  4695 -------------------
  4696 
  4697 * oracles -- these establish an interface between Isabelle and trusted
  4698 external reasoners, which may deliver results as theorems;
  4699 
  4700 * proof objects (in particular record all uses of oracles);
  4701 
  4702 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4703 
  4704 * "constdefs" section in theory files;
  4705 
  4706 * "primrec" section (HOL) no longer requires names;
  4707 
  4708 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4709 
  4710 
  4711 
  4712 New in Isabelle94-5
  4713 -------------------
  4714 
  4715 * reduced space requirements;
  4716 
  4717 * automatic HTML generation from theories;
  4718 
  4719 * theory files no longer require "..." (quotes) around most types;
  4720 
  4721 * new examples, including two proofs of the Church-Rosser theorem;
  4722 
  4723 * non-curried (1994) version of HOL is no longer distributed;
  4724 
  4725 
  4726 
  4727 New in Isabelle94-4
  4728 -------------------
  4729 
  4730 * greatly reduced space requirements;
  4731 
  4732 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4733 
  4734 * searchable theorem database (see the section "Retrieving theorems" on
  4735 page 8 of the Reference Manual);
  4736 
  4737 * new examples, including Grabczewski's monumental case study of the
  4738 Axiom of Choice;
  4739 
  4740 * The previous version of HOL renamed to Old_HOL;
  4741 
  4742 * The new version of HOL (previously called CHOL) uses a curried syntax
  4743 for functions.  Application looks like f a b instead of f(a,b);
  4744 
  4745 * Mutually recursive inductive definitions finally work in HOL;
  4746 
  4747 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4748 translates to the operator "split";
  4749 
  4750 
  4751 
  4752 New in Isabelle94-3
  4753 -------------------
  4754 
  4755 * new infix operator, addss, allowing the classical reasoner to
  4756 perform simplification at each step of its search.  Example:
  4757         fast_tac (cs addss ss)
  4758 
  4759 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4760 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4761 look like (a,b) instead of <a,b>;
  4762 
  4763 * PLEASE NOTE: CHOL will eventually replace HOL!
  4764 
  4765 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4766 It translates to the operator "split".  A new theory of integers is available;
  4767 
  4768 * In ZF, integer numerals now denote two's-complement binary integers.
  4769 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4770 
  4771 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4772 of the Axiom of Choice;
  4773 
  4774 
  4775 
  4776 New in Isabelle94-2
  4777 -------------------
  4778 
  4779 * Significantly faster resolution;
  4780 
  4781 * the different sections in a .thy file can now be mixed and repeated
  4782 freely;
  4783 
  4784 * Database of theorems for FOL, HOL and ZF.  New
  4785 commands including qed, qed_goal and bind_thm store theorems in the database.
  4786 
  4787 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4788 a given theory (thms_of), or find out what theory a theorem was proved in
  4789 (theory_of_thm);
  4790 
  4791 * Bugs fixed in the inductive definition and datatype packages;
  4792 
  4793 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4794 and HOL_dup_cs obsolete;
  4795 
  4796 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4797 have been removed;
  4798 
  4799 * Simpler definition of function space in ZF;
  4800 
  4801 * new results about cardinal and ordinal arithmetic in ZF;
  4802 
  4803 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4804 types;
  4805 
  4806 
  4807 $Id$