NEWS
author huffman
Wed Jun 13 19:14:51 2007 +0200 (2007-06-13)
changeset 23377 197b6a39592c
parent 23369 227c51012cdb
child 23379 d0e3f790bd73
permissions -rw-r--r--
int abbreviates of_nat
     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 * IntDef: The constant "int :: nat => int" has been removed; now
   550   "int" is an abbreviation for "of_nat :: nat => int". Potential
   551   INCOMPATIBILITY due to differences in default simp rules:
   552   - "int (Suc m)" simplifies to "int m + 1" instead of "1 + int m"
   553   - "int (m * n)" simplifies to "int m * int n"
   554 
   555 * Method "algebra" solves polynomial equations over (semi)rings using
   556   Groebner bases. The (semi)ring structure is defined by locales and
   557   the tool setup depends on that generic context. Installing the
   558   method for a specific type involves instantiating the locale and
   559   possibly adding declarations for computation on the coefficients.
   560   The method is already instantiated for natural numbers and for the
   561   axiomatic class of idoms with numerals.  See also the paper by
   562   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   563   underlying this architecture of context-aware proof-tools.
   564 
   565 * constant "List.op @" now named "List.append".  Use ML antiquotations
   566 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   567 possible incompatibilities when working on ML level.
   568 
   569 * Constant renames due to introduction of canonical name prefixing for
   570   class package:
   571 
   572     HOL.abs ~> HOL.minus_class.abs
   573     HOL.divide ~> HOL.divide_class.divide
   574     Nat.power ~> Nat.power_class.power
   575     Nat.size ~> Nat.size_class.size
   576     Numeral.number_of ~> Numeral.number_class.number_of
   577     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   578 
   579 * Rudimentary class target mechanism involves constant renames:
   580 
   581     Orderings.min ~> Orderings.ord_class.min
   582     Orderings.max ~> Orderings.ord_class.max
   583     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   584 
   585 * case expressions and primrec: missing cases now mapped to "undefined"
   586 instead of "arbitrary"
   587 
   588 * new constant "undefined" with axiom "undefined x = undefined"
   589 
   590 * new class "default" with associated constant "default"
   591 
   592 * new function listsum :: 'a list => 'a for arbitrary monoids.
   593   Special syntax: "SUM x <- xs. f x" (and latex variants)
   594 
   595 * new (input only) syntax for Haskell-like list comprehension, eg
   596   [(x,y). x <- xs, y <- ys, x ~= y]
   597   For details see List.thy.
   598 
   599 * The special syntax for function "filter" has changed from [x : xs. P] to
   600   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   601   and for uniformity. INCOMPATIBILITY
   602 
   603 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   604     when generating code.
   605 
   606 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   607     when generating code.
   608 
   609 * Library/Commutative_Ring.thy: switched from recdef to function package;
   610     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   611 
   612 * Some steps towards more uniform lattice theory development in HOL.
   613 
   614     constants "meet" and "join" now named "inf" and "sup"
   615     constant "Meet" now named "Inf"
   616 
   617     classes "meet_semilorder" and "join_semilorder" now named
   618       "lower_semilattice" and "upper_semilattice"
   619     class "lorder" now named "lattice"
   620     class "comp_lat" now named "complete_lattice"
   621 
   622     Instantiation of lattice classes allows explicit definitions
   623     for "inf" and "sup" operations.
   624 
   625   INCOMPATIBILITY.  Theorem renames:
   626 
   627     meet_left_le            ~> inf_le1
   628     meet_right_le           ~> inf_le2
   629     join_left_le            ~> sup_ge1
   630     join_right_le           ~> sup_ge2
   631     meet_join_le            ~> inf_sup_ord
   632     le_meetI                ~> le_infI
   633     join_leI                ~> le_supI
   634     le_meet                 ~> le_inf_iff
   635     le_join                 ~> ge_sup_conv
   636     meet_idempotent         ~> inf_idem
   637     join_idempotent         ~> sup_idem
   638     meet_comm               ~> inf_commute
   639     join_comm               ~> sup_commute
   640     meet_leI1               ~> le_infI1
   641     meet_leI2               ~> le_infI2
   642     le_joinI1               ~> le_supI1
   643     le_joinI2               ~> le_supI2
   644     meet_assoc              ~> inf_assoc
   645     join_assoc              ~> sup_assoc
   646     meet_left_comm          ~> inf_left_commute
   647     meet_left_idempotent    ~> inf_left_idem
   648     join_left_comm          ~> sup_left_commute
   649     join_left_idempotent    ~> sup_left_idem
   650     meet_aci                ~> inf_aci
   651     join_aci                ~> sup_aci
   652     le_def_meet             ~> le_iff_inf
   653     le_def_join             ~> le_iff_sup
   654     join_absorp2            ~> sup_absorb2
   655     join_absorp1            ~> sup_absorb1
   656     meet_absorp1            ~> inf_absorb1
   657     meet_absorp2            ~> inf_absorb2
   658     meet_join_absorp        ~> inf_sup_absorb
   659     join_meet_absorp        ~> sup_inf_absorb
   660     distrib_join_le         ~> distrib_sup_le
   661     distrib_meet_le         ~> distrib_inf_le
   662 
   663     add_meet_distrib_left   ~> add_inf_distrib_left
   664     add_join_distrib_left   ~> add_sup_distrib_left
   665     is_join_neg_meet        ~> is_join_neg_inf
   666     is_meet_neg_join        ~> is_meet_neg_sup
   667     add_meet_distrib_right  ~> add_inf_distrib_right
   668     add_join_distrib_right  ~> add_sup_distrib_right
   669     add_meet_join_distribs  ~> add_sup_inf_distribs
   670     join_eq_neg_meet        ~> sup_eq_neg_inf
   671     meet_eq_neg_join        ~> inf_eq_neg_sup
   672     add_eq_meet_join        ~> add_eq_inf_sup
   673     meet_0_imp_0            ~> inf_0_imp_0
   674     join_0_imp_0            ~> sup_0_imp_0
   675     meet_0_eq_0             ~> inf_0_eq_0
   676     join_0_eq_0             ~> sup_0_eq_0
   677     neg_meet_eq_join        ~> neg_inf_eq_sup
   678     neg_join_eq_meet        ~> neg_sup_eq_inf
   679     join_eq_if              ~> sup_eq_if
   680 
   681     mono_meet               ~> mono_inf
   682     mono_join               ~> mono_sup
   683     meet_bool_eq            ~> inf_bool_eq
   684     join_bool_eq            ~> sup_bool_eq
   685     meet_fun_eq             ~> inf_fun_eq
   686     join_fun_eq             ~> sup_fun_eq
   687     meet_set_eq             ~> inf_set_eq
   688     join_set_eq             ~> sup_set_eq
   689     meet1_iff               ~> inf1_iff
   690     meet2_iff               ~> inf2_iff
   691     meet1I                  ~> inf1I
   692     meet2I                  ~> inf2I
   693     meet1D1                 ~> inf1D1
   694     meet2D1                 ~> inf2D1
   695     meet1D2                 ~> inf1D2
   696     meet2D2                 ~> inf2D2
   697     meet1E                  ~> inf1E
   698     meet2E                  ~> inf2E
   699     join1_iff               ~> sup1_iff
   700     join2_iff               ~> sup2_iff
   701     join1I1                 ~> sup1I1
   702     join2I1                 ~> sup2I1
   703     join1I1                 ~> sup1I1
   704     join2I2                 ~> sup1I2
   705     join1CI                 ~> sup1CI
   706     join2CI                 ~> sup2CI
   707     join1E                  ~> sup1E
   708     join2E                  ~> sup2E
   709 
   710     is_meet_Meet            ~> is_meet_Inf
   711     Meet_bool_def           ~> Inf_bool_def
   712     Meet_fun_def            ~> Inf_fun_def
   713     Meet_greatest           ~> Inf_greatest
   714     Meet_lower              ~> Inf_lower
   715     Meet_set_def            ~> Inf_set_def
   716 
   717     listsp_meetI            ~> listsp_infI
   718     listsp_meet_eq          ~> listsp_inf_eq
   719 
   720     meet_min                ~> inf_min
   721     join_max                ~> sup_max
   722 
   723 * Classes "order" and "linorder": facts "refl", "trans" and
   724 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   725 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   726 
   727 * Classes "order" and "linorder": 
   728 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   729 proofs changed.
   730 
   731 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   732 INCOMPATIBILITY.
   733 
   734 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   735 INCOMPATIBILITY.
   736 
   737 * Added syntactic class "size"; overloaded constant "size" now has
   738 type "'a::size ==> bool"
   739 
   740 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   741 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   742 
   743 * Added method "lexicographic_order" automatically synthesizes
   744 termination relations as lexicographic combinations of size measures
   745 -- 'function' package.
   746 
   747 * HOL/records: generalised field-update to take a function on the
   748 field rather than the new value: r(|A := x|) is translated to A_update
   749 (K x) r The K-combinator that is internally used is called K_record.
   750 INCOMPATIBILITY: Usage of the plain update functions has to be
   751 adapted.
   752  
   753 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   754 0 * x = 0, which are required for a semiring.  Richer structures do
   755 not inherit from semiring_0 anymore, because this property is a
   756 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   757 semiring_0, there is more to prove, but this is mostly trivial.
   758 
   759 * axclass "recpower" was generalized to arbitrary monoids, not just
   760 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   761 commutativity or a semiring property, add the corresponding classes.
   762 
   763 * Unified locale partial_order with class definition (cf. theory
   764 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   765 
   766 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   767 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   768 Isar level, use abbreviations instead.
   769 
   770 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   771 rarely occuring name references (e.g. ``List.op mem.simps'') require
   772 renaming (e.g. ``List.memberl.simps'').
   773 
   774 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   775 INCOMPATIBILITY.
   776 
   777 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   778 
   779 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   780 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   781 significant changes for setting up numeral syntax for types:
   782 
   783   - new constants Numeral.pred and Numeral.succ instead
   784       of former Numeral.bin_pred and Numeral.bin_succ.
   785   - Use integer operations instead of bin_add, bin_mult and so on.
   786   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   787   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   788 
   789 See HOL/Integ/IntArith.thy for an example setup.
   790 
   791 * New top level command 'normal_form' computes the normal form of a
   792 term that may contain free variables. For example ``normal_form
   793 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   794 suitable for heavy-duty computations because the functions are
   795 compiled to ML first.
   796 
   797 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   798 25 like -->); output depends on the "iff" print_mode, the default is
   799 "A = B" (with priority 50).
   800 
   801 * Renamed constants in HOL.thy and Orderings.thy:
   802     op +   ~> HOL.plus_class.plus
   803     op -   ~> HOL.minus_class.minus
   804     uminus ~> HOL.minus_class.uminus
   805     op *   ~> HOL.times_class.times
   806     op <   ~> Orderings.ord_class.less
   807     op <=  ~> Orderings.ord_class.less_eq
   808 
   809 Adaptions may be required in the following cases:
   810 
   811 a) User-defined constants using any of the names "plus", "minus", "times",
   812 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   813 may go wrong.
   814 INCOMPATIBILITY: use more specific names.
   815 
   816 b) Variables named "plus", "minus", "times", "less", "less_eq"
   817 INCOMPATIBILITY: use more specific names.
   818 
   819 c) Permutative equations (e.g. "a + b = b + a")
   820 Since the change of names also changes the order of terms, permutative
   821 rewrite rules may get applied in a different order. Experience shows that
   822 this is rarely the case (only two adaptions in the whole Isabelle
   823 distribution).
   824 INCOMPATIBILITY: rewrite proofs
   825 
   826 d) ML code directly refering to constant names
   827 This in general only affects hand-written proof tactics, simprocs and so on.
   828 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   829 of const_name ML antiquotations.
   830 
   831 * Relations less (<) and less_eq (<=) are also available on type bool.
   832 Modified syntax to disallow nesting without explicit parentheses,
   833 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   834 
   835 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   836 
   837 * Relation composition operator "op O" now has precedence 75 and binds
   838 stronger than union and intersection. INCOMPATIBILITY.
   839 
   840 * The old set interval syntax "{m..n(}" (and relatives) has been
   841 removed.  Use "{m..<n}" (and relatives) instead.
   842 
   843 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   844 "t = s" to False (by simproc "neq_simproc").  For backward
   845 compatibility this can be disabled by ML "reset use_neq_simproc".
   846 
   847 * "m dvd n" where m and n are numbers is evaluated to True/False by
   848 simp.
   849 
   850 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   851 
   852 * Theorem setsum_mult renamed to setsum_right_distrib.
   853 
   854 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   855 ``rule'' method.
   856 
   857 * Reimplemented methods ``sat'' and ``satx'', with several
   858 improvements: goals no longer need to be stated as "<prems> ==>
   859 False", equivalences (i.e. "=" on type bool) are handled, variable
   860 names of the form "lit_<n>" are no longer reserved, significant
   861 speedup.
   862 
   863 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   864 zChaff is still supported as well.
   865 
   866 * 'inductive' and 'datatype': provide projections of mutual rules,
   867 bundled as foo_bar.inducts;
   868 
   869 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   870 Library.
   871 
   872 * Library: moved theory Accessible_Part to main HOL.
   873 
   874 * Library: added theory Coinductive_List of potentially infinite lists
   875 as greatest fixed-point.
   876 
   877 * Library: added theory AssocList which implements (finite) maps as
   878 association lists.
   879 
   880 * Added proof method ``evaluation'' for efficiently solving a goal
   881 (i.e. a boolean expression) by compiling it to ML. The goal is
   882 "proved" (via an oracle) if it evaluates to True.
   883 
   884 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   885 also when invoked by the simplifier.  This results in the simplifier
   886 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   887 fast_arith_split_limit to 0 to obtain the old behavior.
   888 
   889 * Support for hex (0x20) and binary (0b1001) numerals.
   890 
   891 * New method: reify eqs (t), where eqs are equations for an
   892 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   893 parameter, computes a term s::'b and a list xs::'a list and proves the
   894 theorem I xs s = t. This is also known as reification or quoting. The
   895 resulting theorem is applied to the subgoal to substitute t with I xs
   896 s.  If t is omitted, the subgoal itself is reified.
   897 
   898 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   899 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   900 where f is supposed to be a computable function (in the sense of code
   901 generattion). The method uses reify to compute s and xs as above then
   902 applies corr_thm and uses normalization by evaluation to "prove" f s =
   903 r and finally gets the theorem t = r, which is again applied to the
   904 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   905 
   906 * Reflection: Automatic refification now handels binding, an example
   907 is available in HOL/ex/ReflectionEx.thy
   908 
   909 
   910 *** HOL-Algebra ***
   911 
   912 * Formalisation of ideals and the quotient construction over rings.
   913 
   914 * Order and lattice theory no longer based on records.
   915 INCOMPATIBILITY.
   916 
   917 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   918 greatest_closed.  INCOMPATIBILITY.
   919 
   920 * Method algebra is now set up via an attribute.  For examples see
   921 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   922 of algebraic structures.
   923 
   924 * Renamed theory CRing to Ring.
   925 
   926 
   927 *** HOL-Complex ***
   928 
   929 * Theory Real: new method ferrack implements quantifier elimination
   930 for linear arithmetic over the reals. The quantifier elimination
   931 feature is used only for decision, for compatibility with arith. This
   932 means a goal is either solved or left unchanged, no simplification.
   933 
   934 * Hyperreal: Functions root and sqrt are now defined on negative real
   935 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   936 Nonnegativity side conditions have been removed from many lemmas, so
   937 that more subgoals may now be solved by simplification; potential
   938 INCOMPATIBILITY.
   939 
   940 * Real: New axiomatic classes formalize real normed vector spaces and
   941 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   942 and norm :: 'a => real.
   943 
   944 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   945 from reals into other types. The overloaded constant Reals :: 'a set
   946 is now defined as range of_real; potential INCOMPATIBILITY.
   947 
   948 * Real: ML code generation is supported now and hence also quickcheck.
   949 Reals are implemented as arbitrary precision rationals.
   950 
   951 * Hyperreal: Several constants that previously worked only for the
   952 reals have been generalized, so they now work over arbitrary vector
   953 spaces. Type annotations may need to be added in some cases; potential
   954 INCOMPATIBILITY.
   955 
   956   Infinitesimal  :: ('a::real_normed_vector) star set
   957   HFinite        :: ('a::real_normed_vector) star set
   958   HInfinite      :: ('a::real_normed_vector) star set
   959   approx         :: ('a::real_normed_vector) star => 'a star => bool
   960   monad          :: ('a::real_normed_vector) star => 'a star set
   961   galaxy         :: ('a::real_normed_vector) star => 'a star set
   962   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   963   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   964   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   965   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   966   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   967   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   968   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   969   sgn            :: 'a::real_normed_vector => 'a
   970   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   971 
   972 * Complex: Some complex-specific constants are now abbreviations for
   973 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   974 hnorm.  Other constants have been entirely removed in favor of the
   975 polymorphic versions (INCOMPATIBILITY):
   976 
   977   approx        <-- capprox
   978   HFinite       <-- CFinite
   979   HInfinite     <-- CInfinite
   980   Infinitesimal <-- CInfinitesimal
   981   monad         <-- cmonad
   982   galaxy        <-- cgalaxy
   983   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   984   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   985   (ns)deriv     <-- (ns)cderiv
   986 
   987 
   988 *** ML ***
   989 
   990 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
   991 
   992 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   993 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   994 init only required for impure data.  INCOMPATIBILITY: empty really
   995 need to be empty (no dependencies on theory content!)
   996 
   997 * ML within Isar: antiquotations allow to embed statically-checked
   998 formal entities in the source, referring to the context available at
   999 compile-time.  For example:
  1000 
  1001 ML {* @{typ "'a => 'b"} *}
  1002 ML {* @{term "%x. x"} *}
  1003 ML {* @{prop "x == y"} *}
  1004 ML {* @{ctyp "'a => 'b"} *}
  1005 ML {* @{cterm "%x. x"} *}
  1006 ML {* @{cprop "x == y"} *}
  1007 ML {* @{thm asm_rl} *}
  1008 ML {* @{thms asm_rl} *}
  1009 ML {* @{const_name c} *}
  1010 ML {* @{const_syntax c} *}
  1011 ML {* @{context} *}
  1012 ML {* @{theory} *}
  1013 ML {* @{theory Pure} *}
  1014 ML {* @{simpset} *}
  1015 ML {* @{claset} *}
  1016 ML {* @{clasimpset} *}
  1017 
  1018 The same works for sources being ``used'' within an Isar context.
  1019 
  1020 * ML in Isar: improved error reporting; extra verbosity with
  1021 Toplevel.debug enabled.
  1022 
  1023 * Pure/library:
  1024 
  1025   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1026   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1027 
  1028 The semantics of "burrow" is: "take a function with *simulatanously*
  1029 transforms a list of value, and apply it *simulatanously* to a list of
  1030 list of values of the appropriate type". Compare this with "map" which
  1031 would *not* apply its argument function simulatanously but in
  1032 sequence; "fold_burrow" has an additional context.
  1033 
  1034 * Pure/library: functions map2 and fold2 with curried syntax for
  1035 simultanous mapping and folding:
  1036 
  1037     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1038     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1039 
  1040 * Pure/library: indexed lists - some functions in the Isabelle library
  1041 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1042 given more convenient names and signatures reminiscent of similar
  1043 functions for alists, tables, etc:
  1044 
  1045   val nth: 'a list -> int -> 'a 
  1046   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1047   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1048 
  1049 Note that fold_index starts counting at index 0, not 1 like foldln
  1050 used to.
  1051 
  1052 * Pure/library: added general ``divide_and_conquer'' combinator on
  1053 lists.
  1054 
  1055 * Pure/General/table.ML: the join operations now works via exceptions
  1056 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1057 admits slightly more efficient complex applications.
  1058 
  1059 * Pure: datatype Context.generic joins theory/Proof.context and
  1060 provides some facilities for code that works in either kind of
  1061 context, notably GenericDataFun for uniform theory and proof data.
  1062 
  1063 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1064 use Context.generic instead of just theory.
  1065 
  1066 * Pure: simplified internal attribute type, which is now always
  1067 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1068 vs. local (Proof.context) attributes have been discontinued, while
  1069 minimizing code duplication.  Thm.rule_attribute and
  1070 Thm.declaration_attribute build canonical attributes; see also
  1071 structure Context for further operations on Context.generic, notably
  1072 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1073 declarations and definitions.
  1074 
  1075 * Pure/kernel: consts certification ignores sort constraints given in
  1076 signature declarations.  (This information is not relevant to the
  1077 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1078 potential INCOMPATIBILITY.
  1079 
  1080 * Pure: axiomatic type classes are now purely definitional, with
  1081 explicit proofs of class axioms and super class relations performed
  1082 internally.  See Pure/axclass.ML for the main internal interfaces --
  1083 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1084 AxClass.axiomatize_class/classrel/arity supercede
  1085 Sign.add_classes/classrel/arities.
  1086 
  1087 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1088 global/local versions on theory vs. Proof.context have been
  1089 discontinued; Attrib.syntax and Method.syntax have been adapted
  1090 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1091 attributes, methods, etc.
  1092 
  1093 * Pure: several functions of signature "... -> theory -> theory * ..."
  1094 have been reoriented to "... -> theory -> ... * theory" in order to
  1095 allow natural usage in combination with the ||>, ||>>, |-> and
  1096 fold_map combinators.
  1097 
  1098 * Pure: official theorem names (closed derivations) and additional
  1099 comments (tags) are now strictly separate.  Name hints -- which are
  1100 maintained as tags -- may be attached any time without affecting the
  1101 derivation.
  1102 
  1103 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1104 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1105 achieve the old behaviour.
  1106 
  1107 * Pure: the "Goal" constant is now called "prop", supporting a
  1108 slightly more general idea of ``protecting'' meta-level rule
  1109 statements.
  1110 
  1111 * Pure: Logic.(un)varify only works in a global context, which is now
  1112 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1113 Logic.legacy_(un)varify as temporary workaround.
  1114 
  1115 * Pure: structure Name provides scalable operations for generating
  1116 internal variable names, notably Name.variants etc.  This replaces
  1117 some popular functions from term.ML:
  1118 
  1119   Term.variant		->  Name.variant
  1120   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1121   Term.invent_names	->  Name.invent_list
  1122 
  1123 Note that low-level renaming rarely occurs in new code -- operations
  1124 from structure Variable are used instead (see below).
  1125 
  1126 * Pure: structure Variable provides fundamental operations for proper
  1127 treatment of fixed/schematic variables in a context.  For example,
  1128 Variable.import introduces fixes for schematics of given facts and
  1129 Variable.export reverses the effect (up to renaming) -- this replaces
  1130 various freeze_thaw operations.
  1131 
  1132 * Pure: structure Goal provides simple interfaces for
  1133 init/conclude/finish and tactical prove operations (replacing former
  1134 Tactic.prove).  Goal.prove is the canonical way to prove results
  1135 within a given context; Goal.prove_global is a degraded version for
  1136 theory level goals, including a global Drule.standard.  Note that
  1137 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1138 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1139 in a locale context).
  1140 
  1141 * Isar: simplified treatment of user-level errors, using exception
  1142 ERROR of string uniformly.  Function error now merely raises ERROR,
  1143 without any side effect on output channels.  The Isar toplevel takes
  1144 care of proper display of ERROR exceptions.  ML code may use plain
  1145 handle/can/try; cat_error may be used to concatenate errors like this:
  1146 
  1147   ... handle ERROR msg => cat_error msg "..."
  1148 
  1149 Toplevel ML code (run directly or through the Isar toplevel) may be
  1150 embedded into the Isar toplevel with exception display/debug like
  1151 this:
  1152 
  1153   Isar.toplevel (fn () => ...)
  1154 
  1155 INCOMPATIBILITY, removed special transform_error facilities, removed
  1156 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1157 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1158 -- use plain ERROR instead.
  1159 
  1160 * Isar: theory setup now has type (theory -> theory), instead of a
  1161 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1162 
  1163 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1164 subject to ProofContext.debug/verbose flags.
  1165 
  1166 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1167 theory before entering a proof state.  Transactions now always see a
  1168 quasi-functional intermediate checkpoint, both in interactive and
  1169 batch mode.
  1170 
  1171 * Simplifier: the simpset of a running simplification process now
  1172 contains a proof context (cf. Simplifier.the_context), which is the
  1173 very context that the initial simpset has been retrieved from (by
  1174 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1175 (solver, looper etc.) may depend on arbitrary proof data.
  1176 
  1177 * Simplifier.inherit_context inherits the proof context (plus the
  1178 local bounds) of the current simplification process; any simproc
  1179 etc. that calls the Simplifier recursively should do this!  Removed
  1180 former Simplifier.inherit_bounds, which is already included here --
  1181 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1182 specify an explicit context using Simplifier.context/theory_context.
  1183 
  1184 * Simplifier/Classical Reasoner: more abstract interfaces
  1185 change_simpset/claset for modifying the simpset/claset reference of a
  1186 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1187 INCOMPATIBILITY.
  1188 
  1189 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1190 "Trueprop" etc.
  1191 
  1192 
  1193 *** System ***
  1194 
  1195 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1196 locations -- now includes the Isabelle version identifier as well.
  1197 This simplifies use of multiple Isabelle installations.
  1198 
  1199 * isabelle-process: option -S (secure mode) disables some critical
  1200 operations, notably runtime compilation and evaluation of ML source
  1201 code.
  1202 
  1203 
  1204 New in Isabelle2005 (October 2005)
  1205 ----------------------------------
  1206 
  1207 *** General ***
  1208 
  1209 * Theory headers: the new header syntax for Isar theories is
  1210 
  1211   theory <name>
  1212   imports <theory1> ... <theoryN>
  1213   uses <file1> ... <fileM>
  1214   begin
  1215 
  1216 where the 'uses' part is optional.  The previous syntax
  1217 
  1218   theory <name> = <theory1> + ... + <theoryN>:
  1219 
  1220 will disappear in the next release.  Use isatool fixheaders to convert
  1221 existing theory files.  Note that there is no change in ancient
  1222 non-Isar theories now, but these will disappear soon.
  1223 
  1224 * Theory loader: parent theories can now also be referred to via
  1225 relative and absolute paths.
  1226 
  1227 * Command 'find_theorems' searches for a list of criteria instead of a
  1228 list of constants. Known criteria are: intro, elim, dest, name:string,
  1229 simp:term, and any term. Criteria can be preceded by '-' to select
  1230 theorems that do not match. Intro, elim, dest select theorems that
  1231 match the current goal, name:s selects theorems whose fully qualified
  1232 name contain s, and simp:term selects all simplification rules whose
  1233 lhs match term.  Any other term is interpreted as pattern and selects
  1234 all theorems matching the pattern. Available in ProofGeneral under
  1235 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1236 
  1237   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1238 
  1239 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1240 matching the current goal as introduction rule and not having "HOL."
  1241 in their name (i.e. not being defined in theory HOL).
  1242 
  1243 * Command 'thms_containing' has been discontinued in favour of
  1244 'find_theorems'; INCOMPATIBILITY.
  1245 
  1246 * Communication with Proof General is now 8bit clean, which means that
  1247 Unicode text in UTF-8 encoding may be used within theory texts (both
  1248 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1249 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1250 
  1251   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1252   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1253 
  1254 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1255 Classical Reasoner.  Typical big applications run around 2 times
  1256 faster.
  1257 
  1258 
  1259 *** Document preparation ***
  1260 
  1261 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1262 of raw sources.  Only those symbols that do not require additional
  1263 LaTeX packages (depending on comments in isabellesym.sty) are
  1264 displayed properly, everything else is left verbatim.  isatool display
  1265 and isatool print are used as front ends (these are subject to the
  1266 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1267 
  1268 * Command tags control specific markup of certain regions of text,
  1269 notably folding and hiding.  Predefined tags include "theory" (for
  1270 theory begin and end), "proof" for proof commands, and "ML" for
  1271 commands involving ML code; the additional tags "visible" and
  1272 "invisible" are unused by default.  Users may give explicit tag
  1273 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1274 interpretation of tags is determined by the LaTeX job during document
  1275 preparation: see option -V of isatool usedir, or options -n and -t of
  1276 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1277 \isadroptag.
  1278 
  1279 Several document versions may be produced at the same time via isatool
  1280 usedir (the generated index.html will link all of them).  Typical
  1281 specifications include ''-V document=theory,proof,ML'' to present
  1282 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1283 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1284 these parts without any formal replacement text.  The Isabelle site
  1285 default settings produce ''document'' and ''outline'' versions as
  1286 specified above.
  1287 
  1288 * Several new antiquotations:
  1289 
  1290   @{term_type term} prints a term with its type annotated;
  1291 
  1292   @{typeof term} prints the type of a term;
  1293 
  1294   @{const const} is the same as @{term const}, but checks that the
  1295   argument is a known logical constant;
  1296 
  1297   @{term_style style term} and @{thm_style style thm} print a term or
  1298   theorem applying a "style" to it
  1299 
  1300   @{ML text}
  1301 
  1302 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1303 definitions, equations, inequations etc., 'concl' printing only the
  1304 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1305 to print the specified premise.  TermStyle.add_style provides an ML
  1306 interface for introducing further styles.  See also the "LaTeX Sugar"
  1307 document practical applications.  The ML antiquotation prints
  1308 type-checked ML expressions verbatim.
  1309 
  1310 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1311 and 'text' support optional locale specification '(in loc)', which
  1312 specifies the default context for interpreting antiquotations.  For
  1313 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1314 
  1315 * Option 'locale=NAME' of antiquotations specifies an alternative
  1316 context interpreting the subsequent argument.  For example: @{thm
  1317 [locale=lattice] inf_assoc}.
  1318 
  1319 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1320 a proof context.
  1321 
  1322 * Proper output of antiquotations for theory commands involving a
  1323 proof context (such as 'locale' or 'theorem (in loc) ...').
  1324 
  1325 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1326 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1327 
  1328 * isatool usedir: new option -C (default true) controls whether option
  1329 -D should include a copy of the original document directory; -C false
  1330 prevents unwanted effects such as copying of administrative CVS data.
  1331 
  1332 
  1333 *** Pure ***
  1334 
  1335 * Considerably improved version of 'constdefs' command.  Now performs
  1336 automatic type-inference of declared constants; additional support for
  1337 local structure declarations (cf. locales and HOL records), see also
  1338 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1339 sequential dependencies of definitions within a single 'constdefs'
  1340 section; moreover, the declared name needs to be an identifier.  If
  1341 all fails, consider to fall back on 'consts' and 'defs' separately.
  1342 
  1343 * Improved indexed syntax and implicit structures.  First of all,
  1344 indexed syntax provides a notational device for subscripted
  1345 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1346 expressions.  Secondly, in a local context with structure
  1347 declarations, number indexes \<^sub>n or the empty index (default
  1348 number 1) refer to a certain fixed variable implicitly; option
  1349 show_structs controls printing of implicit structures.  Typical
  1350 applications of these concepts involve record types and locales.
  1351 
  1352 * New command 'no_syntax' removes grammar declarations (and
  1353 translations) resulting from the given syntax specification, which is
  1354 interpreted in the same manner as for the 'syntax' command.
  1355 
  1356 * 'Advanced' translation functions (parse_translation etc.) may depend
  1357 on the signature of the theory context being presently used for
  1358 parsing/printing, see also isar-ref manual.
  1359 
  1360 * Improved 'oracle' command provides a type-safe interface to turn an
  1361 ML expression of type theory -> T -> term into a primitive rule of
  1362 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1363 is already included here); see also FOL/ex/IffExample.thy;
  1364 INCOMPATIBILITY.
  1365 
  1366 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1367 before); "cI" is no longer bound, use "c.intro" instead.
  1368 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1369 axclasses vs. locales.
  1370 
  1371 * Improved internal renaming of symbolic identifiers -- attach primes
  1372 instead of base 26 numbers.
  1373 
  1374 * New flag show_question_marks controls printing of leading question
  1375 marks in schematic variable names.
  1376 
  1377 * In schematic variable names, *any* symbol following \<^isub> or
  1378 \<^isup> is now treated as part of the base name.  For example, the
  1379 following works without printing of awkward ".0" indexes:
  1380 
  1381   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1382     by simp
  1383 
  1384 * Inner syntax includes (*(*nested*) comments*).
  1385 
  1386 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1387 annotations as "(00...)".
  1388 
  1389 * Clear separation of logical types and nonterminals, where the latter
  1390 may only occur in 'syntax' specifications or type abbreviations.
  1391 Before that distinction was only partially implemented via type class
  1392 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1393 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1394 exotic syntax specifications may require further adaption
  1395 (e.g. Cube/Cube.thy).
  1396 
  1397 * Removed obsolete type class "logic", use the top sort {} instead.
  1398 Note that non-logical types should be declared as 'nonterminals'
  1399 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1400 specifications.
  1401 
  1402 * Attributes 'induct' and 'cases': type or set names may now be
  1403 locally fixed variables as well.
  1404 
  1405 * Simplifier: can now control the depth to which conditional rewriting
  1406 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1407 Limit.
  1408 
  1409 * Simplifier: simplification procedures may now take the current
  1410 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1411 interface), which is very useful for calling the Simplifier
  1412 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1413 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1414 low-level mk_simproc no longer applies Logic.varify internally, to
  1415 allow for use in a context of fixed variables.
  1416 
  1417 * thin_tac now works even if the assumption being deleted contains !!
  1418 or ==>.  More generally, erule now works even if the major premise of
  1419 the elimination rule contains !! or ==>.
  1420 
  1421 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1422 
  1423 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1424 from Pure, which contains all common declarations already.  Both
  1425 theories are defined via plain Isabelle/Isar .thy files.
  1426 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1427 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1428 use isatool fixcpure to adapt your theory and ML sources.
  1429 
  1430 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1431 selections of theorems in named facts via index ranges.
  1432 
  1433 * 'print_theorems': in theory mode, really print the difference
  1434 wrt. the last state (works for interactive theory development only),
  1435 in proof mode print all local facts (cf. 'print_facts');
  1436 
  1437 * 'hide': option '(open)' hides only base names.
  1438 
  1439 * More efficient treatment of intermediate checkpoints in interactive
  1440 theory development.
  1441 
  1442 * Code generator is now invoked via code_module (incremental code
  1443 generation) and code_library (modular code generation, ML structures
  1444 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1445 must be quoted when used as identifiers.
  1446 
  1447 * New 'value' command for reading, evaluating and printing terms using
  1448 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1449 quoted when used as identifier.
  1450 
  1451 
  1452 *** Locales ***
  1453 
  1454 * New commands for the interpretation of locale expressions in
  1455 theories (1), locales (2) and proof contexts (3).  These generate
  1456 proof obligations from the expression specification.  After the
  1457 obligations have been discharged, theorems of the expression are added
  1458 to the theory, target locale or proof context.  The synopsis of the
  1459 commands is a follows:
  1460 
  1461   (1) interpretation expr inst
  1462   (2) interpretation target < expr
  1463   (3) interpret expr inst
  1464 
  1465 Interpretation in theories and proof contexts require a parameter
  1466 instantiation of terms from the current context.  This is applied to
  1467 specifications and theorems of the interpreted expression.
  1468 Interpretation in locales only permits parameter renaming through the
  1469 locale expression.  Interpretation is smart in that interpretations
  1470 that are active already do not occur in proof obligations, neither are
  1471 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1472 inspect active interpretations of a particular locale.  For details,
  1473 see the Isar Reference manual.  Examples can be found in
  1474 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1475 
  1476 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1477 'interpret' instead.
  1478 
  1479 * New context element 'constrains' for adding type constraints to
  1480 parameters.
  1481 
  1482 * Context expressions: renaming of parameters with syntax
  1483 redeclaration.
  1484 
  1485 * Locale declaration: 'includes' disallowed.
  1486 
  1487 * Proper static binding of attribute syntax -- i.e. types / terms /
  1488 facts mentioned as arguments are always those of the locale definition
  1489 context, independently of the context of later invocations.  Moreover,
  1490 locale operations (renaming and type / term instantiation) are applied
  1491 to attribute arguments as expected.
  1492 
  1493 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1494 actual attributes; rare situations may require Attrib.attribute to
  1495 embed those attributes into Attrib.src that lack concrete syntax.
  1496 Attribute implementations need to cooperate properly with the static
  1497 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1498 Attrib.XXX_thm etc. already do the right thing without further
  1499 intervention.  Only unusual applications -- such as "where" or "of"
  1500 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1501 on the context and the facts involved -- may have to assign parsed
  1502 values to argument tokens explicitly.
  1503 
  1504 * Changed parameter management in theorem generation for long goal
  1505 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1506 theorem statement in rare situations.
  1507 
  1508 * Locale inspection command 'print_locale' omits notes elements.  Use
  1509 'print_locale!' to have them included in the output.
  1510 
  1511 
  1512 *** Provers ***
  1513 
  1514 * Provers/hypsubst.ML: improved version of the subst method, for
  1515 single-step rewriting: it now works in bound variable contexts. New is
  1516 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1517 rewrite a different subterm than the original subst method, which is
  1518 still available as 'simplesubst'.
  1519 
  1520 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1521 and quasi orders.
  1522 
  1523 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1524 reflexive-transitive closure of relations.
  1525 
  1526 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1527 limit (previously hard-coded with a value of 20) user-definable.
  1528 
  1529 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1530 is peformed already.  Object-logics merely need to finish their
  1531 initial simpset configuration as before.  INCOMPATIBILITY.
  1532 
  1533 
  1534 *** HOL ***
  1535 
  1536 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1537 
  1538   syntax (epsilon)
  1539     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1540 
  1541 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1542 and x-symbol; use option '-m epsilon' to get it actually printed.
  1543 Moreover, the mathematically important symbolic identifier \<epsilon>
  1544 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1545 
  1546 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1547 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1548 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1549 support corresponding Isar calculations.
  1550 
  1551 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1552 instead of ":".
  1553 
  1554 * theory SetInterval: changed the syntax for open intervals:
  1555 
  1556   Old       New
  1557   {..n(}    {..<n}
  1558   {)n..}    {n<..}
  1559   {m..n(}   {m..<n}
  1560   {)m..n}   {m<..n}
  1561   {)m..n(}  {m<..<n}
  1562 
  1563 The old syntax is still supported but will disappear in the next
  1564 release.  For conversion use the following Emacs search and replace
  1565 patterns (these are not perfect but work quite well):
  1566 
  1567   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1568   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1569 
  1570 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1571 equalities in commutative rings; method 'algebra' provides a generic
  1572 interface.
  1573 
  1574 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1575 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1576 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1577 be a tuple pattern.
  1578 
  1579 Some new syntax forms are available:
  1580 
  1581   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1582   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1583   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1584   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1585 
  1586 The latter form "\<Sum>x < k. e" used to be based on a separate
  1587 function "Summation", which has been discontinued.
  1588 
  1589 * theory Finite_Set: in structured induction proofs, the insert case
  1590 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1591 (insert F x)'.
  1592 
  1593 * The 'refute' command has been extended to support a much larger
  1594 fragment of HOL, including axiomatic type classes, constdefs and
  1595 typedefs, inductive datatypes and recursion.
  1596 
  1597 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1598 Requires zChaff with proof generation to be installed.  See
  1599 HOL/ex/SAT_Examples.thy for examples.
  1600 
  1601 * Datatype induction via method 'induct' now preserves the name of the
  1602 induction variable. For example, when proving P(xs::'a list) by
  1603 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1604 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1605 in unstructured proof scripts.
  1606 
  1607 * Reworked implementation of records.  Improved scalability for
  1608 records with many fields, avoiding performance problems for type
  1609 inference. Records are no longer composed of nested field types, but
  1610 of nested extension types. Therefore the record type only grows linear
  1611 in the number of extensions and not in the number of fields.  The
  1612 top-level (users) view on records is preserved.  Potential
  1613 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1614 old record representation. The type generated for a record is called
  1615 <record_name>_ext_type.
  1616 
  1617 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1618 proofs triggered by a record definition or a simproc (if
  1619 quick_and_dirty is enabled).  Definitions of large records can take
  1620 quite long.
  1621 
  1622 New simproc record_upd_simproc for simplification of multiple record
  1623 updates enabled by default.  Moreover, trivial updates are also
  1624 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1625 occasionally, since simplification is more powerful by default.
  1626 
  1627 * typedef: proper support for polymorphic sets, which contain extra
  1628 type-variables in the term.
  1629 
  1630 * Simplifier: automatically reasons about transitivity chains
  1631 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1632 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1633 old proofs break occasionally as simplification may now solve more
  1634 goals than previously.
  1635 
  1636 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1637 present.  Works for all partial orders (class "order"), in particular
  1638 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1639 just like y <= x.
  1640 
  1641 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1642 bound variable or a constant then the let is unfolded.  Otherwise
  1643 first a is simplified to b, and then f b is simplified to g. If
  1644 possible we abstract b from g arriving at "let x = b in h x",
  1645 otherwise we unfold the let and arrive at g.  The simproc can be
  1646 enabled/disabled by the reference use_let_simproc.  Potential
  1647 INCOMPATIBILITY since simplification is more powerful by default.
  1648 
  1649 * Classical reasoning: the meson method now accepts theorems as arguments.
  1650 
  1651 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1652 jobs to provide advice on the provability of subgoals.
  1653 
  1654 * Theory OrderedGroup and Ring_and_Field: various additions and
  1655 improvements to faciliate calculations involving equalities and
  1656 inequalities.
  1657 
  1658 The following theorems have been eliminated or modified
  1659 (INCOMPATIBILITY):
  1660 
  1661   abs_eq             now named abs_of_nonneg
  1662   abs_of_ge_0        now named abs_of_nonneg
  1663   abs_minus_eq       now named abs_of_nonpos
  1664   imp_abs_id         now named abs_of_nonneg
  1665   imp_abs_neg_id     now named abs_of_nonpos
  1666   mult_pos           now named mult_pos_pos
  1667   mult_pos_le        now named mult_nonneg_nonneg
  1668   mult_pos_neg_le    now named mult_nonneg_nonpos
  1669   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1670   mult_neg           now named mult_neg_neg
  1671   mult_neg_le        now named mult_nonpos_nonpos
  1672 
  1673 * Theory Parity: added rules for simplifying exponents.
  1674 
  1675 * Theory List:
  1676 
  1677 The following theorems have been eliminated or modified
  1678 (INCOMPATIBILITY):
  1679 
  1680   list_all_Nil       now named list_all.simps(1)
  1681   list_all_Cons      now named list_all.simps(2)
  1682   list_all_conv      now named list_all_iff
  1683   set_mem_eq         now named mem_iff
  1684 
  1685 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1686 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1687 
  1688 
  1689 *** HOL-Complex ***
  1690 
  1691 * Theory RealDef: better support for embedding natural numbers and
  1692 integers in the reals.
  1693 
  1694 The following theorems have been eliminated or modified
  1695 (INCOMPATIBILITY):
  1696 
  1697   exp_ge_add_one_self  now requires no hypotheses
  1698   real_of_int_add      reversed direction of equality (use [symmetric])
  1699   real_of_int_minus    reversed direction of equality (use [symmetric])
  1700   real_of_int_diff     reversed direction of equality (use [symmetric])
  1701   real_of_int_mult     reversed direction of equality (use [symmetric])
  1702 
  1703 * Theory RComplete: expanded support for floor and ceiling functions.
  1704 
  1705 * Theory Ln is new, with properties of the natural logarithm
  1706 
  1707 * Hyperreal: There is a new type constructor "star" for making
  1708 nonstandard types.  The old type names are now type synonyms:
  1709 
  1710   hypreal = real star
  1711   hypnat = nat star
  1712   hcomplex = complex star
  1713 
  1714 * Hyperreal: Many groups of similarly-defined constants have been
  1715 replaced by polymorphic versions (INCOMPATIBILITY):
  1716 
  1717   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1718 
  1719   starset      <-- starsetNat, starsetC
  1720   *s*          <-- *sNat*, *sc*
  1721   starset_n    <-- starsetNat_n, starsetC_n
  1722   *sn*         <-- *sNatn*, *scn*
  1723   InternalSets <-- InternalNatSets, InternalCSets
  1724 
  1725   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1726   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1727   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1728   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1729   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1730 
  1731 * Hyperreal: Many type-specific theorems have been removed in favor of
  1732 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1733 
  1734   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1735   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1736   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1737   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1738   right_minus <-- hypreal_add_minus
  1739   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1740   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1741   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1742   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1743   mult_1_right <-- hcomplex_mult_one_right
  1744   mult_zero_left <-- hcomplex_mult_zero_left
  1745   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1746   right_distrib <-- hypnat_add_mult_distrib2
  1747   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1748   right_inverse <-- hypreal_mult_inverse
  1749   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1750   order_refl <-- {hypreal,hypnat}_le_refl
  1751   order_trans <-- {hypreal,hypnat}_le_trans
  1752   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1753   order_less_le <-- {hypreal,hypnat}_less_le
  1754   linorder_linear <-- {hypreal,hypnat}_le_linear
  1755   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1756   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1757   add_nonneg_nonneg <-- hypreal_le_add_order
  1758 
  1759 * Hyperreal: Separate theorems having to do with type-specific
  1760 versions of constants have been merged into theorems that apply to the
  1761 new polymorphic constants (INCOMPATIBILITY):
  1762 
  1763   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1764   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1765   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1766   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1767   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1768   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1769   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1770   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1771   STAR_diff <-- {STAR,STARC}_diff
  1772   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1773     STARC_hcomplex_of_complex}_image_subset
  1774   starset_n_Un <-- starset{Nat,C}_n_Un
  1775   starset_n_Int <-- starset{Nat,C}_n_Int
  1776   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1777   starset_n_diff <-- starset{Nat,C}_n_diff
  1778   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1779   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1780   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1781   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1782   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1783   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1784   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1785   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1786   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1787   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1788   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1789   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1790   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1791   starfun_diff <-- starfun{C,RC,CR}_diff
  1792   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1793   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1794   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1795   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1796   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1797   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1798   starfun_Id <-- starfunC_Id
  1799   starfun_approx <-- starfun{Nat,CR}_approx
  1800   starfun_capprox <-- starfun{C,RC}_capprox
  1801   starfun_abs <-- starfunNat_rabs
  1802   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1803   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1804   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1805   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1806   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1807   starfun_add_approx <-- starfunCR_add_approx
  1808   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1809   starfun_divide <-- starfun{C,CR,RC}_divide
  1810   starfun_n <-- starfun{Nat,C}_n
  1811   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1812   starfun_n_add <-- starfun{Nat,C}_n_add
  1813   starfun_n_add_minus <-- starfunNat_n_add_minus
  1814   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1815   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1816   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1817 
  1818   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1819   star_n_minus <-- {hypreal,hcomplex}_minus
  1820   star_n_diff <-- {hypreal,hcomplex}_diff
  1821   star_n_mult <-- {hypreal,hcomplex}_mult
  1822   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1823   star_n_le <-- {hypreal,hypnat}_le
  1824   star_n_less <-- {hypreal,hypnat}_less
  1825   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1826   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1827   star_n_abs <-- hypreal_hrabs
  1828   star_n_divide <-- hcomplex_divide
  1829 
  1830   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1831   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1832   star_of_diff <-- hypreal_of_real_diff
  1833   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1834   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1835   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1836   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1837   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1838   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1839   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1840   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1841   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1842   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1843   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1844   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1845   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1846   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1847   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1848   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1849   star_of_power <-- hypreal_of_real_power
  1850   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1851 
  1852 * Hyperreal: new method "transfer" that implements the transfer
  1853 principle of nonstandard analysis. With a subgoal that mentions
  1854 nonstandard types like "'a star", the command "apply transfer"
  1855 replaces it with an equivalent one that mentions only standard types.
  1856 To be successful, all free variables must have standard types; non-
  1857 standard variables must have explicit universal quantifiers.
  1858 
  1859 * Hyperreal: A theory of Taylor series.
  1860 
  1861 
  1862 *** HOLCF ***
  1863 
  1864 * Discontinued special version of 'constdefs' (which used to support
  1865 continuous functions) in favor of the general Pure one with full
  1866 type-inference.
  1867 
  1868 * New simplification procedure for solving continuity conditions; it
  1869 is much faster on terms with many nested lambda abstractions (cubic
  1870 instead of exponential time).
  1871 
  1872 * New syntax for domain package: selector names are now optional.
  1873 Parentheses should be omitted unless argument is lazy, for example:
  1874 
  1875   domain 'a stream = cons "'a" (lazy "'a stream")
  1876 
  1877 * New command 'fixrec' for defining recursive functions with pattern
  1878 matching; defining multiple functions with mutual recursion is also
  1879 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1880 sinr, or any data constructor defined by the domain package. The given
  1881 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1882 syntax and examples.
  1883 
  1884 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1885 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1886 but the proof obligation additionally includes an admissibility
  1887 requirement. The packages generate instances of class cpo or pcpo,
  1888 with continuity and strictness theorems for Rep and Abs.
  1889 
  1890 * HOLCF: Many theorems have been renamed according to a more standard naming
  1891 scheme (INCOMPATIBILITY):
  1892 
  1893   foo_inject:  "foo$x = foo$y ==> x = y"
  1894   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1895   foo_less:    "(foo$x << foo$y) = (x << y)"
  1896   foo_strict:  "foo$UU = UU"
  1897   foo_defined: "... ==> foo$x ~= UU"
  1898   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1899 
  1900 
  1901 *** ZF ***
  1902 
  1903 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1904 including the First Isomorphism Theorem (on quotienting by the kernel
  1905 of a homomorphism).
  1906 
  1907 * ZF/Simplifier: install second copy of type solver that actually
  1908 makes use of TC rules declared to Isar proof contexts (or locales);
  1909 the old version is still required for ML proof scripts.
  1910 
  1911 
  1912 *** Cube ***
  1913 
  1914 * Converted to Isar theory format; use locales instead of axiomatic
  1915 theories.
  1916 
  1917 
  1918 *** ML ***
  1919 
  1920 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1921 for ||>, ||>>, |>>,
  1922 
  1923 * Pure/library.ML no longer defines its own option datatype, but uses
  1924 that of the SML basis, which has constructors NONE and SOME instead of
  1925 None and Some, as well as exception Option.Option instead of OPTION.
  1926 The functions the, if_none, is_some, is_none have been adapted
  1927 accordingly, while Option.map replaces apsome.
  1928 
  1929 * Pure/library.ML: the exception LIST has been given up in favour of
  1930 the standard exceptions Empty and Subscript, as well as
  1931 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1932 superceded by the standard hd and tl functions etc.
  1933 
  1934 A number of basic list functions are no longer exported to the ML
  1935 toplevel, as they are variants of predefined functions.  The following
  1936 suggests how one can translate existing code:
  1937 
  1938     rev_append xs ys = List.revAppend (xs, ys)
  1939     nth_elem (i, xs) = List.nth (xs, i)
  1940     last_elem xs = List.last xs
  1941     flat xss = List.concat xss
  1942     seq fs = List.app fs
  1943     partition P xs = List.partition P xs
  1944     mapfilter f xs = List.mapPartial f xs
  1945 
  1946 * Pure/library.ML: several combinators for linear functional
  1947 transformations, notably reverse application and composition:
  1948 
  1949   x |> f                f #> g
  1950   (x, y) |-> f          f #-> g
  1951 
  1952 * Pure/library.ML: introduced/changed precedence of infix operators:
  1953 
  1954   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1955   infix 2 ?;
  1956   infix 3 o oo ooo oooo;
  1957   infix 4 ~~ upto downto;
  1958 
  1959 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1960 infix operators.
  1961 
  1962 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1963 fold_map support linear functional transformations and nesting.  For
  1964 example:
  1965 
  1966   fold f [x1, ..., xN] y =
  1967     y |> f x1 |> ... |> f xN
  1968 
  1969   (fold o fold) f [xs1, ..., xsN] y =
  1970     y |> fold f xs1 |> ... |> fold f xsN
  1971 
  1972   fold f [x1, ..., xN] =
  1973     f x1 #> ... #> f xN
  1974 
  1975   (fold o fold) f [xs1, ..., xsN] =
  1976     fold f xs1 #> ... #> fold f xsN
  1977 
  1978 * Pure/library.ML: the following selectors on type 'a option are
  1979 available:
  1980 
  1981   the:               'a option -> 'a  (*partial*)
  1982   these:             'a option -> 'a  where 'a = 'b list
  1983   the_default: 'a -> 'a option -> 'a
  1984   the_list:          'a option -> 'a list
  1985 
  1986 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1987 basic operations for association lists, following natural argument
  1988 order; moreover the explicit equality predicate passed here avoids
  1989 potentially expensive polymorphic runtime equality checks.
  1990 The old functions may be expressed as follows:
  1991 
  1992   assoc = uncurry (AList.lookup (op =))
  1993   assocs = these oo AList.lookup (op =)
  1994   overwrite = uncurry (AList.update (op =)) o swap
  1995 
  1996 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1997 
  1998   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1999   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2000 
  2001 replacing make_keylist and keyfilter (occassionally used)
  2002 Naive rewrites:
  2003 
  2004   make_keylist = AList.make
  2005   keyfilter = AList.find (op =)
  2006 
  2007 * eq_fst and eq_snd now take explicit equality parameter, thus
  2008   avoiding eqtypes. Naive rewrites:
  2009 
  2010     eq_fst = eq_fst (op =)
  2011     eq_snd = eq_snd (op =)
  2012 
  2013 * Removed deprecated apl and apr (rarely used).
  2014   Naive rewrites:
  2015 
  2016     apl (n, op) =>>= curry op n
  2017     apr (op, m) =>>= fn n => op (n, m)
  2018 
  2019 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2020 provides a reasonably efficient light-weight implementation of sets as
  2021 lists.
  2022 
  2023 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2024 few new operations; existing lookup and update are now curried to
  2025 follow natural argument order (for use with fold etc.);
  2026 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2027 
  2028 * Pure/General: output via the Isabelle channels of
  2029 writeln/warning/error etc. is now passed through Output.output, with a
  2030 hook for arbitrary transformations depending on the print_mode
  2031 (cf. Output.add_mode -- the first active mode that provides a output
  2032 function wins).  Already formatted output may be embedded into further
  2033 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2034 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2035 accommodate easy composition of diagnostic messages etc.  Programmers
  2036 rarely need to care about Output.output or Output.raw at all, with
  2037 some notable exceptions: Output.output is required when bypassing the
  2038 standard channels (writeln etc.), or in token translations to produce
  2039 properly formatted results; Output.raw is required when capturing
  2040 already output material that will eventually be presented to the user
  2041 a second time.  For the default print mode, both Output.output and
  2042 Output.raw have no effect.
  2043 
  2044 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2045 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2046 cumulative results are displayed at the end of a batch session.
  2047 
  2048 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2049 replaced by File.platform_path and File.shell_path (with appropriate
  2050 hooks).  This provides a clean interface for unusual systems where the
  2051 internal and external process view of file names are different.
  2052 
  2053 * Pure: more efficient orders for basic syntactic entities: added
  2054 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2055 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2056 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2057 orders now -- potential INCOMPATIBILITY for code that depends on a
  2058 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2059 Library.sort_strings on result).
  2060 
  2061 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2062 fold_types traverse types/terms from left to right, observing natural
  2063 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2064 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2065 
  2066 * Pure: name spaces have been refined, with significant changes of the
  2067 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2068 to extern(_table).  The plain name entry path is superceded by a
  2069 general 'naming' context, which also includes the 'policy' to produce
  2070 a fully qualified name and external accesses of a fully qualified
  2071 name; NameSpace.extend is superceded by context dependent
  2072 Sign.declare_name.  Several theory and proof context operations modify
  2073 the naming context.  Especially note Theory.restore_naming and
  2074 ProofContext.restore_naming to get back to a sane state; note that
  2075 Theory.add_path is no longer sufficient to recover from
  2076 Theory.absolute_path in particular.
  2077 
  2078 * Pure: new flags short_names (default false) and unique_names
  2079 (default true) for controlling output of qualified names.  If
  2080 short_names is set, names are printed unqualified.  If unique_names is
  2081 reset, the name prefix is reduced to the minimum required to achieve
  2082 the original result when interning again, even if there is an overlap
  2083 with earlier declarations.
  2084 
  2085 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2086 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2087 (useful for printing error messages).  INCOMPATIBILITY.
  2088 
  2089 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2090 Theory.theory are now identified, referring to the universal
  2091 Context.theory (see Pure/context.ML).  Actual signature and theory
  2092 content is managed as theory data.  The old code and interfaces were
  2093 spread over many files and structures; the new arrangement introduces
  2094 considerable INCOMPATIBILITY to gain more clarity:
  2095 
  2096   Context -- theory management operations (name, identity, inclusion,
  2097     parents, ancestors, merge, etc.), plus generic theory data;
  2098 
  2099   Sign -- logical signature and syntax operations (declaring consts,
  2100     types, etc.), plus certify/read for common entities;
  2101 
  2102   Theory -- logical theory operations (stating axioms, definitions,
  2103     oracles), plus a copy of logical signature operations (consts,
  2104     types, etc.); also a few basic management operations (Theory.copy,
  2105     Theory.merge, etc.)
  2106 
  2107 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2108 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2109 for convenience -- they merely return the theory.
  2110 
  2111 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2112 
  2113 * Pure: the Isar proof context type is already defined early in Pure
  2114 as Context.proof (note that ProofContext.context and Proof.context are
  2115 aliases, where the latter is the preferred name).  This enables other
  2116 Isabelle components to refer to that type even before Isar is present.
  2117 
  2118 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2119 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2120 any of these kinds.  For example, Sign.intern typeK is now
  2121 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2122 Theory.hide_types.  Also note that former
  2123 Theory.hide_classes/types/consts are now
  2124 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2125 internalize their arguments!  INCOMPATIBILITY.
  2126 
  2127 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2128 datatype thmref (with constructors Name and NameSelection) instead of
  2129 plain string -- INCOMPATIBILITY;
  2130 
  2131 * Pure: cases produced by proof methods specify options, where NONE
  2132 means to remove case bindings -- INCOMPATIBILITY in
  2133 (RAW_)METHOD_CASES.
  2134 
  2135 * Pure: the following operations retrieve axioms or theorems from a
  2136 theory node or theory hierarchy, respectively:
  2137 
  2138   Theory.axioms_of: theory -> (string * term) list
  2139   Theory.all_axioms_of: theory -> (string * term) list
  2140   PureThy.thms_of: theory -> (string * thm) list
  2141   PureThy.all_thms_of: theory -> (string * thm) list
  2142 
  2143 * Pure: print_tac now outputs the goal through the trace channel.
  2144 
  2145 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2146 Reference Toplevel.debug (default false) controls detailed printing
  2147 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2148 controls execution profiling -- set to 1 for time and 2 for space
  2149 (both increase the runtime).
  2150 
  2151 * Isar session: The initial use of ROOT.ML is now always timed,
  2152 i.e. the log will show the actual process times, in contrast to the
  2153 elapsed wall-clock time that the outer shell wrapper produces.
  2154 
  2155 * Simplifier: improved handling of bound variables (nameless
  2156 representation, avoid allocating new strings).  Simprocs that invoke
  2157 the Simplifier recursively should use Simplifier.inherit_bounds to
  2158 avoid local name clashes.  Failure to do so produces warnings
  2159 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2160 for further details.
  2161 
  2162 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2163 bindings for all theorems stored within a given theory; this may help
  2164 in porting non-Isar theories to Isar ones, while keeping ML proof
  2165 scripts for the time being.
  2166 
  2167 * ML operator HTML.with_charset specifies the charset begin used for
  2168 generated HTML files.  For example:
  2169 
  2170   HTML.with_charset "utf-8" use_thy "Hebrew";
  2171   HTML.with_charset "utf-8" use_thy "Chinese";
  2172 
  2173 
  2174 *** System ***
  2175 
  2176 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2177 isabelle, isatool etc.).
  2178 
  2179 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2180 isatool doc, isatool mkdir, display_drafts etc.).
  2181 
  2182 * isatool usedir: option -f allows specification of the ML file to be
  2183 used by Isabelle; default is ROOT.ML.
  2184 
  2185 * New isatool version outputs the version identifier of the Isabelle
  2186 distribution being used.
  2187 
  2188 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2189 (containing Boolean satisfiability problems) into Isabelle/HOL
  2190 theories.
  2191 
  2192 
  2193 
  2194 New in Isabelle2004 (April 2004)
  2195 --------------------------------
  2196 
  2197 *** General ***
  2198 
  2199 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2200   Replaces linorder.ML.
  2201 
  2202 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2203   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2204   (\<a>...\<z>), are now considered normal letters, and can therefore
  2205   be used anywhere where an ASCII letter (a...zA...Z) has until
  2206   now. COMPATIBILITY: This obviously changes the parsing of some
  2207   terms, especially where a symbol has been used as a binder, say
  2208   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2209   as an identifier.  Fix it by inserting a space around former
  2210   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2211   existing theory and ML files.
  2212 
  2213 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2214 
  2215 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2216   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2217   a normal (but invisible) letter. For multiple letter subscripts repeat
  2218   \<^isub> like this: x\<^isub>1\<^isub>2.
  2219 
  2220 * Pure: There are now sub-/superscripts that can span more than one
  2221   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2222   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2223   superscript. The new control characters are not identifier parts.
  2224 
  2225 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2226   content of "..." to the latex file instead of \isacntrl... . The "..."
  2227   may consist of any printable characters excluding the end bracket >.
  2228 
  2229 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2230   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2231   declare constants "final", which prevents their being given a definition
  2232   later.  It is useful for constants whose behaviour is fixed axiomatically
  2233   rather than definitionally, such as the meta-logic connectives.
  2234 
  2235 * Pure: 'instance' now handles general arities with general sorts
  2236   (i.e. intersections of classes),
  2237 
  2238 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2239   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2240   It can be changed to alter the colors/layout of generated pages.
  2241 
  2242 
  2243 *** Isar ***
  2244 
  2245 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2246   cut_tac, subgoal_tac and thin_tac:
  2247   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2248     locales are no longer forced to write Isar proof scripts.
  2249     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2250     emulations.
  2251   - INCOMPATIBILITY: names of variables to be instantiated may no
  2252     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2253     This is consistent with the instantiation attribute "where".
  2254 
  2255 * Attributes "where" and "of":
  2256   - Now take type variables of instantiated theorem into account when reading
  2257     the instantiation string.  This fixes a bug that caused instantiated
  2258     theorems to have too special types in some circumstances.
  2259   - "where" permits explicit instantiations of type variables.
  2260 
  2261 * Calculation commands "moreover" and "also" no longer interfere with
  2262   current facts ("this"), admitting arbitrary combinations with "then"
  2263   and derived forms.
  2264 
  2265 * Locales:
  2266   - Goal statements involving the context element "includes" no longer
  2267     generate theorems with internal delta predicates (those ending on
  2268     "_axioms") in the premise.
  2269     Resolve particular premise with <locale>.intro to obtain old form.
  2270   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2271     specification and "includes" elements in goal statement.
  2272   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2273     [intro?] and [elim?] (respectively) by default.
  2274   - Experimental command for instantiation of locales in proof contexts:
  2275         instantiate <label>[<attrs>]: <loc>
  2276     Instantiates locale <loc> and adds all its theorems to the current context
  2277     taking into account their attributes.  Label and attrs are optional
  2278     modifiers, like in theorem declarations.  If present, names of
  2279     instantiated theorems are qualified with <label>, and the attributes
  2280     <attrs> are applied after any attributes these theorems might have already.
  2281       If the locale has assumptions, a chained fact of the form
  2282     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2283     are derived.  The command does not support old-style locales declared
  2284     with "locale (open)".
  2285       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2286 
  2287 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2288   (Isar) contexts.
  2289 
  2290 
  2291 *** HOL ***
  2292 
  2293 * Proof import: new image HOL4 contains the imported library from
  2294   the HOL4 system with about 2500 theorems. It is imported by
  2295   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2296   can be used like any other Isabelle image.  See
  2297   HOL/Import/HOL/README for more information.
  2298 
  2299 * Simplifier:
  2300   - Much improved handling of linear and partial orders.
  2301     Reasoners for linear and partial orders are set up for type classes
  2302     "linorder" and "order" respectively, and are added to the default simpset
  2303     as solvers.  This means that the simplifier can build transitivity chains
  2304     to solve goals from the assumptions.
  2305   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2306     of blast or auto after simplification become unnecessary because the goal
  2307     is solved by simplification already.
  2308 
  2309 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2310     all proved in axiomatic type classes for semirings, rings and fields.
  2311 
  2312 * Numerics:
  2313   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2314     now formalized using the Ring_and_Field theory mentioned above.
  2315   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2316     than before, because now they are set up once in a generic manner.
  2317   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2318     Look for the general versions in Ring_and_Field (and Power if they concern
  2319     exponentiation).
  2320 
  2321 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2322 
  2323 * Records:
  2324   - Record types are now by default printed with their type abbreviation
  2325     instead of the list of all field types. This can be configured via
  2326     the reference "print_record_type_abbr".
  2327   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2328     (not enabled by default).
  2329   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2330     EX x. x = sel r to True (not enabled by default).
  2331   - Tactic "record_split_simp_tac" to split and simplify records added.
  2332 
  2333 * 'specification' command added, allowing for definition by
  2334   specification.  There is also an 'ax_specification' command that
  2335   introduces the new constants axiomatically.
  2336 
  2337 * arith(_tac) is now able to generate counterexamples for reals as well.
  2338 
  2339 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2340 
  2341 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2342   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2343 
  2344 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2345   matrix theory to linear programming.
  2346 
  2347 * Unions and Intersections:
  2348   The latex output syntax of UN and INT has been changed
  2349   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2350   i.e. the index formulae has become a subscript.
  2351   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2352 
  2353 * Unions and Intersections over Intervals:
  2354   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2355   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2356   like in normal math, and corresponding versions for < and for intersection.
  2357 
  2358 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2359   lexicographic dictonary ordering has been added as "lexord".
  2360 
  2361 * ML: the legacy theory structures Int and List have been removed. They had
  2362   conflicted with ML Basis Library structures having the same names.
  2363 
  2364 * 'refute' command added to search for (finite) countermodels.  Only works
  2365   for a fragment of HOL.  The installation of an external SAT solver is
  2366   highly recommended.  See "HOL/Refute.thy" for details.
  2367 
  2368 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2369   formulae under an assignment of free variables to random values.
  2370   In contrast to 'refute', it can deal with inductive datatypes,
  2371   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2372   for examples.
  2373 
  2374 
  2375 *** HOLCF ***
  2376 
  2377 * Streams now come with concatenation and are part of the HOLCF image
  2378 
  2379 
  2380 
  2381 New in Isabelle2003 (May 2003)
  2382 ------------------------------
  2383 
  2384 *** General ***
  2385 
  2386 * Provers/simplifier:
  2387 
  2388   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2389     Assumptions are now subject to complete mutual simplification,
  2390     not just from left to right. The simplifier now preserves
  2391     the order of assumptions.
  2392 
  2393     Potential INCOMPATIBILITY:
  2394 
  2395     -- simp sometimes diverges where the old version did
  2396        not, e.g. invoking simp on the goal
  2397 
  2398         [| P (f x); y = x; f x = f y |] ==> Q
  2399 
  2400        now gives rise to the infinite reduction sequence
  2401 
  2402         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2403 
  2404        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2405        kind of problem.
  2406 
  2407     -- Tactics combining classical reasoner and simplification (such as auto)
  2408        are also affected by this change, because many of them rely on
  2409        simp. They may sometimes diverge as well or yield a different numbers
  2410        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2411        in case of problems. Sometimes subsequent calls to the classical
  2412        reasoner will fail because a preceeding call to the simplifier too
  2413        eagerly simplified the goal, e.g. deleted redundant premises.
  2414 
  2415   - The simplifier trace now shows the names of the applied rewrite rules
  2416 
  2417   - You can limit the number of recursive invocations of the simplifier
  2418     during conditional rewriting (where the simplifie tries to solve the
  2419     conditions before applying the rewrite rule):
  2420     ML "simp_depth_limit := n"
  2421     where n is an integer. Thus you can force termination where previously
  2422     the simplifier would diverge.
  2423 
  2424   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2425 
  2426   - No longer aborts on failed congruence proof.  Instead, the
  2427     congruence is ignored.
  2428 
  2429 * Pure: New generic framework for extracting programs from constructive
  2430   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2431   as HOL/Extraction for some case studies.
  2432 
  2433 * Pure: The main goal of the proof state is no longer shown by default, only
  2434 the subgoals. This behaviour is controlled by a new flag.
  2435    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2436 (ML: Proof.show_main_goal).
  2437 
  2438 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2439 rules whose conclusion matches subgoal 1:
  2440       PG menu: Isabelle/Isar -> Show me -> matching rules
  2441 The rules are ordered by how closely they match the subgoal.
  2442 In particular, rules that solve a subgoal outright are displayed first
  2443 (or rather last, the way they are printed).
  2444 (ML: ProofGeneral.print_intros())
  2445 
  2446 * Pure: New flag trace_unify_fail causes unification to print
  2447 diagnostic information (PG: in trace buffer) when it fails. This is
  2448 useful for figuring out why single step proofs like rule, erule or
  2449 assumption failed.
  2450 
  2451 * Pure: Locale specifications now produce predicate definitions
  2452 according to the body of text (covering assumptions modulo local
  2453 definitions); predicate "loc_axioms" covers newly introduced text,
  2454 while "loc" is cumulative wrt. all included locale expressions; the
  2455 latter view is presented only on export into the global theory
  2456 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2457 on the old view without predicates;
  2458 
  2459 * Pure: predefined locales "var" and "struct" are useful for sharing
  2460 parameters (as in CASL, for example); just specify something like
  2461 ``var x + var y + struct M'' as import;
  2462 
  2463 * Pure: improved thms_containing: proper indexing of facts instead of
  2464 raw theorems; check validity of results wrt. current name space;
  2465 include local facts of proof configuration (also covers active
  2466 locales), cover fixed variables in index; may use "_" in term
  2467 specification; an optional limit for the number of printed facts may
  2468 be given (the default is 40);
  2469 
  2470 * Pure: disallow duplicate fact bindings within new-style theory files
  2471 (batch-mode only);
  2472 
  2473 * Provers: improved induct method: assumptions introduced by case
  2474 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2475 the goal statement); "foo" still refers to all facts collectively;
  2476 
  2477 * Provers: the function blast.overloaded has been removed: all constants
  2478 are regarded as potentially overloaded, which improves robustness in exchange
  2479 for slight decrease in efficiency;
  2480 
  2481 * Provers/linorder: New generic prover for transitivity reasoning over
  2482 linear orders.  Note: this prover is not efficient!
  2483 
  2484 * Isar: preview of problems to finish 'show' now produce an error
  2485 rather than just a warning (in interactive mode);
  2486 
  2487 
  2488 *** HOL ***
  2489 
  2490 * arith(_tac)
  2491 
  2492  - Produces a counter example if it cannot prove a goal.
  2493    Note that the counter example may be spurious if the goal is not a formula
  2494    of quantifier-free linear arithmetic.
  2495    In ProofGeneral the counter example appears in the trace buffer.
  2496 
  2497  - Knows about div k and mod k where k is a numeral of type nat or int.
  2498 
  2499  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2500    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2501    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2502 
  2503 * simp's arithmetic capabilities have been enhanced a bit: it now
  2504 takes ~= in premises into account (by performing a case split);
  2505 
  2506 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2507 are distributed over a sum of terms;
  2508 
  2509 * New tactic "trans_tac" and method "trans" instantiate
  2510 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2511 "<=", "<" and "=").
  2512 
  2513 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2514 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2515 
  2516 * 'typedef' command has new option "open" to suppress the set
  2517 definition;
  2518 
  2519 * functions Min and Max on finite sets have been introduced (theory
  2520 Finite_Set);
  2521 
  2522 * attribute [symmetric] now works for relations as well; it turns
  2523 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2524 
  2525 * induct over a !!-quantified statement (say !!x1..xn):
  2526   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2527 
  2528 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2529 %x. None. Warning: empty_def now refers to the previously hidden definition
  2530 of the empty set.
  2531 
  2532 * Algebra: formalization of classical algebra.  Intended as base for
  2533 any algebraic development in Isabelle.  Currently covers group theory
  2534 (up to Sylow's theorem) and ring theory (Universal Property of
  2535 Univariate Polynomials).  Contributions welcome;
  2536 
  2537 * GroupTheory: deleted, since its material has been moved to Algebra;
  2538 
  2539 * Complex: new directory of the complex numbers with numeric constants,
  2540 nonstandard complex numbers, and some complex analysis, standard and
  2541 nonstandard (Jacques Fleuriot);
  2542 
  2543 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2544 
  2545 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2546 Fleuriot);
  2547 
  2548 * Real/HahnBanach: updated and adapted to locales;
  2549 
  2550 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2551 Gray and Kramer);
  2552 
  2553 * UNITY: added the Meier-Sanders theory of progress sets;
  2554 
  2555 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2556 as abstract algorithms, instantiated to the JVM;
  2557 
  2558 * Bali: Java source language formalization. Type system, operational
  2559 semantics, axiomatic semantics. Supported language features:
  2560 classes, interfaces, objects,virtual methods, static methods,
  2561 static/instance fields, arrays, access modifiers, definite
  2562 assignment, exceptions.
  2563 
  2564 
  2565 *** ZF ***
  2566 
  2567 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2568 universe, etc.);
  2569 
  2570 * Main ZF: virtually all theories converted to new-style format;
  2571 
  2572 
  2573 *** ML ***
  2574 
  2575 * Pure: Tactic.prove provides sane interface for internal proofs;
  2576 omits the infamous "standard" operation, so this is more appropriate
  2577 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2578 
  2579 * Pure: improved error reporting of simprocs;
  2580 
  2581 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2582 up simprocs;
  2583 
  2584 
  2585 *** Document preparation ***
  2586 
  2587 * uses \par instead of \\ for line breaks in theory text. This may
  2588 shift some page breaks in large documents. To get the old behaviour
  2589 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2590 
  2591 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2592 other packages
  2593 
  2594 * \<euro> now needs package babel/greek instead of marvosym (which
  2595 broke \Rightarrow)
  2596 
  2597 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2598 textcomp package)
  2599 
  2600 
  2601 
  2602 New in Isabelle2002 (March 2002)
  2603 --------------------------------
  2604 
  2605 *** Document preparation ***
  2606 
  2607 * greatly simplified document preparation setup, including more
  2608 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2609 instructive isatool mkdir; users should basically be able to get
  2610 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2611 users may run a separate document processing stage manually like this:
  2612 "isatool usedir -D output HOL Test && isatool document Test/output";
  2613 
  2614 * theory dependency graph may now be incorporated into documents;
  2615 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2616 with \includegraphics of LaTeX;
  2617 
  2618 * proper spacing of consecutive markup elements, especially text
  2619 blocks after section headings;
  2620 
  2621 * support bold style (for single symbols only), input syntax is like
  2622 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2623 
  2624 * \<bullet> is now output as bold \cdot by default, which looks much
  2625 better in printed text;
  2626 
  2627 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2628 note that these symbols are currently unavailable in Proof General /
  2629 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2630 
  2631 * isatool latex no longer depends on changed TEXINPUTS, instead
  2632 isatool document copies the Isabelle style files to the target
  2633 location;
  2634 
  2635 
  2636 *** Isar ***
  2637 
  2638 * Pure/Provers: improved proof by cases and induction;
  2639   - 'case' command admits impromptu naming of parameters (such as
  2640     "case (Suc n)");
  2641   - 'induct' method divinates rule instantiation from the inductive
  2642     claim; no longer requires excessive ?P bindings for proper
  2643     instantiation of cases;
  2644   - 'induct' method properly enumerates all possibilities of set/type
  2645     rules; as a consequence facts may be also passed through *type*
  2646     rules without further ado;
  2647   - 'induct' method now derives symbolic cases from the *rulified*
  2648     rule (before it used to rulify cases stemming from the internal
  2649     atomized version); this means that the context of a non-atomic
  2650     statement becomes is included in the hypothesis, avoiding the
  2651     slightly cumbersome show "PROP ?case" form;
  2652   - 'induct' may now use elim-style induction rules without chaining
  2653     facts, using ``missing'' premises from the goal state; this allows
  2654     rules stemming from inductive sets to be applied in unstructured
  2655     scripts, while still benefitting from proper handling of non-atomic
  2656     statements; NB: major inductive premises need to be put first, all
  2657     the rest of the goal is passed through the induction;
  2658   - 'induct' proper support for mutual induction involving non-atomic
  2659     rule statements (uses the new concept of simultaneous goals, see
  2660     below);
  2661   - append all possible rule selections, but only use the first
  2662     success (no backtracking);
  2663   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2664   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2665   - added 'print_induct_rules' (covered by help item in recent Proof
  2666     General versions);
  2667   - moved induct/cases attributes to Pure, methods to Provers;
  2668   - generic method setup instantiated for FOL and HOL;
  2669 
  2670 * Pure: support multiple simultaneous goal statements, for example
  2671 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2672 meta-level mechanism, this acts as if several individual goals had
  2673 been stated separately; in particular common proof methods need to be
  2674 repeated in order to cover all claims; note that a single elimination
  2675 step is *not* sufficient to establish the two conjunctions, so this
  2676 fails:
  2677 
  2678   assume "A & B" then have A and B ..   (*".." fails*)
  2679 
  2680 better use "obtain" in situations as above; alternative refer to
  2681 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2682 
  2683 * Pure: proper integration with ``locales''; unlike the original
  2684 version by Florian Kammller, Isar locales package high-level proof
  2685 contexts rather than raw logical ones (e.g. we admit to include
  2686 attributes everywhere); operations on locales include merge and
  2687 rename; support for implicit arguments (``structures''); simultaneous
  2688 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2689 some examples;
  2690 
  2691 * Pure: the following commands have been ``localized'', supporting a
  2692 target locale specification "(in name)": 'lemma', 'theorem',
  2693 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2694 stored both within the locale and at the theory level (exported and
  2695 qualified by the locale name);
  2696 
  2697 * Pure: theory goals may now be specified in ``long'' form, with
  2698 ad-hoc contexts consisting of arbitrary locale elements. for example
  2699 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2700 definitions may be given, too); the result is a meta-level rule with
  2701 the context elements being discharged in the obvious way;
  2702 
  2703 * Pure: new proof command 'using' allows to augment currently used
  2704 facts after a goal statement ('using' is syntactically analogous to
  2705 'apply', but acts on the goal's facts only); this allows chained facts
  2706 to be separated into parts given before and after a claim, as in
  2707 ``from a and b have C using d and e <proof>'';
  2708 
  2709 * Pure: renamed "antecedent" case to "rule_context";
  2710 
  2711 * Pure: new 'judgment' command records explicit information about the
  2712 object-logic embedding (used by several tools internally); no longer
  2713 use hard-wired "Trueprop";
  2714 
  2715 * Pure: added 'corollary' command;
  2716 
  2717 * Pure: fixed 'token_translation' command;
  2718 
  2719 * Pure: removed obsolete 'exported' attribute;
  2720 
  2721 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2722 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2723 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2724 
  2725 * Pure: method 'atomize' presents local goal premises as object-level
  2726 statements (atomic meta-level propositions); setup controlled via
  2727 rewrite rules declarations of 'atomize' attribute; example
  2728 application: 'induct' method with proper rule statements in improper
  2729 proof *scripts*;
  2730 
  2731 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2732 now consider the syntactic context of assumptions, giving a better
  2733 chance to get type-inference of the arguments right (this is
  2734 especially important for locales);
  2735 
  2736 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2737 mode;
  2738 
  2739 * Pure/obtain: the formal conclusion "thesis", being marked as
  2740 ``internal'', may no longer be reference directly in the text;
  2741 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2742 situations;
  2743 
  2744 * Pure: generic 'sym' attribute which declares a rule both as pure
  2745 'elim?' and for the 'symmetric' operation;
  2746 
  2747 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2748 text; the fixed correlation with particular command syntax has been
  2749 discontinued;
  2750 
  2751 * Pure: new method 'rules' is particularly well-suited for proof
  2752 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2753 but often produces more compact proof terms with less detours;
  2754 
  2755 * Pure/Provers/classical: simplified integration with pure rule
  2756 attributes and methods; the classical "intro?/elim?/dest?"
  2757 declarations coincide with the pure ones; the "rule" method no longer
  2758 includes classically swapped intros; "intro" and "elim" methods no
  2759 longer pick rules from the context; also got rid of ML declarations
  2760 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2761 INCOMPATIBILITY;
  2762 
  2763 * Provers/classical: attribute 'swapped' produces classical inversions
  2764 of introduction rules;
  2765 
  2766 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2767 rules instead of full simplifier context; 'iff' attribute handles
  2768 conditional rules;
  2769 
  2770 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2771 
  2772 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2773 "(permissive)" option to recover old behavior;
  2774 
  2775 * HOL: 'inductive' no longer features separate (collective) attributes
  2776 for 'intros' (was found too confusing);
  2777 
  2778 * HOL: properly declared induction rules less_induct and
  2779 wf_induct_rule;
  2780 
  2781 
  2782 *** HOL ***
  2783 
  2784 * HOL: moved over to sane numeral syntax; the new policy is as
  2785 follows:
  2786 
  2787   - 0 and 1 are polymorphic constants, which are defined on any
  2788   numeric type (nat, int, real etc.);
  2789 
  2790   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2791   binary representation internally;
  2792 
  2793   - type nat has special constructor Suc, and generally prefers Suc 0
  2794   over 1::nat and Suc (Suc 0) over 2::nat;
  2795 
  2796 This change may cause significant problems of INCOMPATIBILITY; here
  2797 are some hints on converting existing sources:
  2798 
  2799   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2800   entities, so expressions involving "-" (unary or binary minus) need
  2801   to be spaced properly;
  2802 
  2803   - existing occurrences of "1" may need to be constraint "1::nat" or
  2804   even replaced by Suc 0; similar for old "2";
  2805 
  2806   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2807 
  2808   - remove all special provisions on numerals in proofs;
  2809 
  2810 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2811 representation (depends on bin_arith_simps in the default context);
  2812 
  2813 * HOL: symbolic syntax for x^2 (numeral 2);
  2814 
  2815 * HOL: the class of all HOL types is now called "type" rather than
  2816 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2817 in axclass/classes, instance/arities, and (usually rare) occurrences
  2818 in typings (of consts etc.); internally the class is called
  2819 "HOL.type", ML programs should refer to HOLogic.typeS;
  2820 
  2821 * HOL/record package improvements:
  2822   - new derived operations "fields" to build a partial record section,
  2823     "extend" to promote a fixed record to a record scheme, and
  2824     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2825     declared as simp by default;
  2826   - shared operations ("more", "fields", etc.) now need to be always
  2827     qualified) --- potential INCOMPATIBILITY;
  2828   - removed "make_scheme" operations (use "make" with "extend") --
  2829     INCOMPATIBILITY;
  2830   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2831   - provides cases/induct rules for use with corresponding Isar
  2832     methods (for concrete records, record schemes, concrete more
  2833     parts, and schematic more parts -- in that order);
  2834   - internal definitions directly based on a light-weight abstract
  2835     theory of product types over typedef rather than datatype;
  2836 
  2837 * HOL: generic code generator for generating executable ML code from
  2838 specifications; specific support for HOL constructs such as inductive
  2839 datatypes and sets, as well as recursive functions; can be invoked
  2840 via 'generate_code' theory section;
  2841 
  2842 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2843 
  2844 * HOL: consolidated and renamed several theories.  In particular:
  2845         Ord.thy has been absorbed into HOL.thy
  2846         String.thy has been absorbed into List.thy
  2847 
  2848 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2849 (beware of argument permutation!);
  2850 
  2851 * HOL: linorder_less_split superseded by linorder_cases;
  2852 
  2853 * HOL/List: "nodups" renamed to "distinct";
  2854 
  2855 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2856 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2857   - Ex_def has changed, now need to use some_eq_ex
  2858 
  2859 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2860 in this (rare) case use:
  2861 
  2862   delSWrapper "split_all_tac"
  2863   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2864 
  2865 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2866 MAY FAIL;
  2867 
  2868 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2869 Isabelle's type classes, ^ on functions and relations has too general
  2870 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2871 necessary to attach explicit type constraints;
  2872 
  2873 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2874 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2875 renamed accordingly (eg "compI" -> "rel_compI").
  2876 
  2877 * HOL: syntax translations now work properly with numerals and records
  2878 expressions;
  2879 
  2880 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2881 of "lam" -- INCOMPATIBILITY;
  2882 
  2883 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2884 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2885 renamed "Product_Type.unit";
  2886 
  2887 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2888 
  2889 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2890 the "cases" method);
  2891 
  2892 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2893 Florian Kammller);
  2894 
  2895 * HOL/IMP: updated and converted to new-style theory format; several
  2896 parts turned into readable document, with proper Isar proof texts and
  2897 some explanations (by Gerwin Klein);
  2898 
  2899 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2900 
  2901 * HOL-Hyperreal is now a logic image;
  2902 
  2903 
  2904 *** HOLCF ***
  2905 
  2906 * Isar: consts/constdefs supports mixfix syntax for continuous
  2907 operations;
  2908 
  2909 * Isar: domain package adapted to new-style theory format, e.g. see
  2910 HOLCF/ex/Dnat.thy;
  2911 
  2912 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2913 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2914 lift.induct_tac, always use UU instead of Undef;
  2915 
  2916 * HOLCF/IMP: updated and converted to new-style theory;
  2917 
  2918 
  2919 *** ZF ***
  2920 
  2921 * Isar: proper integration of logic-specific tools and packages,
  2922 including theory commands '(co)inductive', '(co)datatype',
  2923 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2924 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2925 
  2926 * theory Main no longer includes AC; for the Axiom of Choice, base
  2927 your theory on Main_ZFC;
  2928 
  2929 * the integer library now covers quotients and remainders, with many
  2930 laws relating division to addition, multiplication, etc.;
  2931 
  2932 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2933 typeless version of the formalism;
  2934 
  2935 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2936 format;
  2937 
  2938 * ZF/Induct: new directory for examples of inductive definitions,
  2939 including theory Multiset for multiset orderings; converted to
  2940 new-style theory format;
  2941 
  2942 * ZF: many new theorems about lists, ordinals, etc.;
  2943 
  2944 
  2945 *** General ***
  2946 
  2947 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2948 variable proof controls level of detail: 0 = no proofs (only oracle
  2949 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2950 also ref manual for further ML interfaces;
  2951 
  2952 * Pure/axclass: removed obsolete ML interface
  2953 goal_subclass/goal_arity;
  2954 
  2955 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2956 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2957 separate tokens, so expressions involving minus need to be spaced
  2958 properly;
  2959 
  2960 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2961 rather than "infixl" or "infixr";
  2962 
  2963 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2964 sort constraint specifications in type inference; e.g. "x::_::foo"
  2965 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2966 type variable);
  2967 
  2968 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2969 control output of nested => (types); the default behavior is
  2970 "type_brackets";
  2971 
  2972 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2973 tokens into AST constants;
  2974 
  2975 * Pure/syntax: prefer later declarations of translations and print
  2976 translation functions; potential INCOMPATIBILITY: need to reverse
  2977 multiple declarations for same syntax element constant;
  2978 
  2979 * Pure/show_hyps reset by default (in accordance to existing Isar
  2980 practice);
  2981 
  2982 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2983 addSafter;
  2984 
  2985 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2986 as well;
  2987 
  2988 * system: tested support for MacOS X; should be able to get Isabelle +
  2989 Proof General to work in a plain Terminal after installing Poly/ML
  2990 (e.g. from the Isabelle distribution area) and GNU bash alone
  2991 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2992 support requires further installations, e.g. from
  2993 http://fink.sourceforge.net/);
  2994 
  2995 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2996 
  2997 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2998 of 40 MB), cf. ML_OPTIONS;
  2999 
  3000 * system: Proof General keywords specification is now part of the
  3001 Isabelle distribution (see etc/isar-keywords.el);
  3002 
  3003 * system: support for persistent Proof General sessions (refrain from
  3004 outdating all loaded theories on startup); user may create writable
  3005 logic images like this: ``isabelle -q HOL Test'';
  3006 
  3007 * system: smart selection of Isabelle process versus Isabelle
  3008 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3009 run both "isabelle" and "Isabelle" even if file names are badly
  3010 damaged (executable inspects the case of the first letter of its own
  3011 name); added separate "isabelle-process" and "isabelle-interface";
  3012 
  3013 * system: refrain from any attempt at filtering input streams; no
  3014 longer support ``8bit'' encoding of old isabelle font, instead proper
  3015 iso-latin characters may now be used; the related isatools
  3016 "symbolinput" and "nonascii" have disappeared as well;
  3017 
  3018 * system: removed old "xterm" interface (the print modes "xterm" and
  3019 "xterm_color" are still available for direct use in a suitable
  3020 terminal);
  3021 
  3022 
  3023 
  3024 New in Isabelle99-2 (February 2001)
  3025 -----------------------------------
  3026 
  3027 *** Overview of INCOMPATIBILITIES ***
  3028 
  3029 * HOL: please note that theories in the Library and elsewhere often use the
  3030 new-style (Isar) format; to refer to their theorems in an ML script you must
  3031 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3032 
  3033 * HOL: inductive package no longer splits induction rule aggressively,
  3034 but only as far as specified by the introductions given; the old
  3035 format may be recovered via ML function complete_split_rule or attribute
  3036 'split_rule (complete)';
  3037 
  3038 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3039 gfp_Tarski to gfp_unfold;
  3040 
  3041 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3042 
  3043 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3044 relation); infix "^^" has been renamed "``"; infix "``" has been
  3045 renamed "`"; "univalent" has been renamed "single_valued";
  3046 
  3047 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3048 operation;
  3049 
  3050 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3051 
  3052 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3053 
  3054 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3055 consequence, it is no longer monotonic wrt. the local goal context
  3056 (which is now passed through the inductive cases);
  3057 
  3058 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3059 \<gg> to \<ggreater>;
  3060 
  3061 
  3062 *** Document preparation ***
  3063 
  3064 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3065 available: are "it" for near math-mode best-style output, "sl" for
  3066 slanted text style, and "tt" for plain type-writer; if no
  3067 \isabellestyle command is given, output is according to slanted
  3068 type-writer);
  3069 
  3070 * support sub/super scripts (for single symbols only), input syntax is
  3071 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3072 
  3073 * some more standard symbols; see Appendix A of the system manual for
  3074 the complete list of symbols defined in isabellesym.sty;
  3075 
  3076 * improved isabelle style files; more abstract symbol implementation
  3077 (should now use \isamath{...} and \isatext{...} in custom symbol
  3078 definitions);
  3079 
  3080 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3081 state; Note that presentation of goal states does not conform to
  3082 actual human-readable proof documents.  Please do not include goal
  3083 states into document output unless you really know what you are doing!
  3084 
  3085 * proper indentation of antiquoted output with proportional LaTeX
  3086 fonts;
  3087 
  3088 * no_document ML operator temporarily disables LaTeX document
  3089 generation;
  3090 
  3091 * isatool unsymbolize tunes sources for plain ASCII communication;
  3092 
  3093 
  3094 *** Isar ***
  3095 
  3096 * Pure: Isar now suffers initial goal statements to contain unbound
  3097 schematic variables (this does not conform to actual readable proof
  3098 documents, due to unpredictable outcome and non-compositional proof
  3099 checking); users who know what they are doing may use schematic goals
  3100 for Prolog-style synthesis of proven results;
  3101 
  3102 * Pure: assumption method (an implicit finishing) now handles actual
  3103 rules as well;
  3104 
  3105 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3106 initial goal, declare "that" only as Pure intro (only for single
  3107 steps); the "that" rule assumption may now be involved in implicit
  3108 finishing, thus ".." becomes a feasible for trivial obtains;
  3109 
  3110 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3111 instance proofs may be performed by "..";
  3112 
  3113 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3114 statements as well;
  3115 
  3116 * Pure: more robust selection of calculational rules;
  3117 
  3118 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3119 rule (as well as the assumption rule);
  3120 
  3121 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3122 lemmas, using the graph browser tool;
  3123 
  3124 * Pure: predict failure of "show" in interactive mode;
  3125 
  3126 * Pure: 'thms_containing' now takes actual terms as arguments;
  3127 
  3128 * HOL: improved method 'induct' --- now handles non-atomic goals
  3129 (potential INCOMPATIBILITY); tuned error handling;
  3130 
  3131 * HOL: cases and induct rules now provide explicit hints about the
  3132 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3133 any remaining facts are inserted into the goal verbatim;
  3134 
  3135 * HOL: local contexts (aka cases) may now contain term bindings as
  3136 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3137 the result to be shown in each case;
  3138 
  3139 * HOL: added 'recdef_tc' command;
  3140 
  3141 * isatool convert assists in eliminating legacy ML scripts;
  3142 
  3143 
  3144 *** HOL ***
  3145 
  3146 * HOL/Library: a collection of generic theories to be used together
  3147 with main HOL; the theory loader path already includes this directory
  3148 by default; the following existing theories have been moved here:
  3149 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3150 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3151 
  3152 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3153 modelling and verification task performed in Isabelle/HOL +
  3154 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3155 
  3156 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3157 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3158 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3159 'domain', this makes the theory consistent with mathematical
  3160 literature;
  3161 
  3162 * HOL basics: added overloaded operations "inverse" and "divide"
  3163 (infix "/"), syntax for generic "abs" operation, generic summation
  3164 operator \<Sum>;
  3165 
  3166 * HOL/typedef: simplified package, provide more useful rules (see also
  3167 HOL/subset.thy);
  3168 
  3169 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3170 now expressed as a proper nested rule (old-style tactic scripts may
  3171 require atomize_strip_tac to cope with non-atomic premises);
  3172 
  3173 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3174 to "split_conv" (old name still available for compatibility);
  3175 
  3176 * HOL: improved concrete syntax for strings (e.g. allows translation
  3177 rules with string literals);
  3178 
  3179 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3180  and Fleuriot's mechanization of analysis, including the transcendental
  3181  functions for the reals;
  3182 
  3183 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3184 
  3185 
  3186 *** CTT ***
  3187 
  3188 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3189 "lam" is displayed as TWO lambda-symbols
  3190 
  3191 * CTT: theory Main now available, containing everything (that is, Bool
  3192 and Arith);
  3193 
  3194 
  3195 *** General ***
  3196 
  3197 * Pure: the Simplifier has been implemented properly as a derived rule
  3198 outside of the actual kernel (at last!); the overall performance
  3199 penalty in practical applications is about 50%, while reliability of
  3200 the Isabelle inference kernel has been greatly improved;
  3201 
  3202 * print modes "brackets" and "no_brackets" control output of nested =>
  3203 (types) and ==> (props); the default behaviour is "brackets";
  3204 
  3205 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3206 as assumptions as well;
  3207 
  3208 * system: support Poly/ML 4.0;
  3209 
  3210 * system: isatool install handles KDE version 1 or 2;
  3211 
  3212 
  3213 
  3214 New in Isabelle99-1 (October 2000)
  3215 ----------------------------------
  3216 
  3217 *** Overview of INCOMPATIBILITIES ***
  3218 
  3219 * HOL: simplification of natural numbers is much changed; to partly
  3220 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3221 issue the following ML commands:
  3222 
  3223   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3224   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3225 
  3226 * HOL: simplification no longer dives into case-expressions; this is
  3227 controlled by "t.weak_case_cong" for each datatype t;
  3228 
  3229 * HOL: nat_less_induct renamed to less_induct;
  3230 
  3231 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3232 fixsome to patch .thy and .ML sources automatically;
  3233 
  3234   select_equality  -> some_equality
  3235   select_eq_Ex     -> some_eq_ex
  3236   selectI2EX       -> someI2_ex
  3237   selectI2         -> someI2
  3238   selectI          -> someI
  3239   select1_equality -> some1_equality
  3240   Eps_sym_eq       -> some_sym_eq_trivial
  3241   Eps_eq           -> some_eq_trivial
  3242 
  3243 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3244 
  3245 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3246 instead);
  3247 
  3248 * HOL: the recursion equations generated by 'recdef' are now called
  3249 f.simps instead of f.rules;
  3250 
  3251 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3252 
  3253 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3254 sometimes be needed;
  3255 
  3256 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3257 
  3258 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3259 
  3260 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3261 product is now "<*>" instead of "Times"; the lexicographic product is
  3262 now "<*lex*>" instead of "**";
  3263 
  3264 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3265 of main HOL, but was unused); better use HOL's datatype package;
  3266 
  3267 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3268 the old syntax may be recovered as follows:
  3269 
  3270   syntax (symbols)
  3271     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3272       (infixl "\\<oplus>" 100)
  3273 
  3274 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3275 
  3276 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3277 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3278 internally;
  3279 
  3280 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3281 changed from A/r to A//r;
  3282 
  3283 * ZF: new treatment of arithmetic (nat & int) may break some old
  3284 proofs;
  3285 
  3286 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3287 rulify -> rule_format, elimify -> elim_format, ...);
  3288 
  3289 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3290 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3291 should have to change intro!! to intro? only); replaced "delrule" by
  3292 "rule del";
  3293 
  3294 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3295 
  3296 * Provers: strengthened force_tac by using new first_best_tac;
  3297 
  3298 * LaTeX document preparation: several changes of isabelle.sty (see
  3299 lib/texinputs);
  3300 
  3301 
  3302 *** Document preparation ***
  3303 
  3304 * formal comments (text blocks etc.) in new-style theories may now
  3305 contain antiquotations of thm/prop/term/typ/text to be presented
  3306 according to latex print mode; concrete syntax is like this:
  3307 @{term[show_types] "f(x) = a + x"};
  3308 
  3309 * isatool mkdir provides easy setup of Isabelle session directories,
  3310 including proper document sources;
  3311 
  3312 * generated LaTeX sources are now deleted after successful run
  3313 (isatool document -c); may retain a copy somewhere else via -D option
  3314 of isatool usedir;
  3315 
  3316 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3317 style files, achieving self-contained LaTeX sources and simplifying
  3318 LaTeX debugging;
  3319 
  3320 * old-style theories now produce (crude) LaTeX output as well;
  3321 
  3322 * browser info session directories are now self-contained (may be put
  3323 on WWW server seperately); improved graphs of nested sessions; removed
  3324 graph for 'all sessions';
  3325 
  3326 * several improvements in isabelle style files; \isabellestyle{it}
  3327 produces fake math mode output; \isamarkupheader is now \section by
  3328 default; see lib/texinputs/isabelle.sty etc.;
  3329 
  3330 
  3331 *** Isar ***
  3332 
  3333 * Isar/Pure: local results and corresponding term bindings are now
  3334 subject to Hindley-Milner polymorphism (similar to ML); this
  3335 accommodates incremental type-inference very nicely;
  3336 
  3337 * Isar/Pure: new derived language element 'obtain' supports
  3338 generalized existence reasoning;
  3339 
  3340 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3341 support accumulation of results, without applying any rules yet;
  3342 useful to collect intermediate results without explicit name
  3343 references, and for use with transitivity rules with more than 2
  3344 premises;
  3345 
  3346 * Isar/Pure: scalable support for case-analysis type proofs: new
  3347 'case' language element refers to local contexts symbolically, as
  3348 produced by certain proof methods; internally, case names are attached
  3349 to theorems as "tags";
  3350 
  3351 * Isar/Pure: theory command 'hide' removes declarations from
  3352 class/type/const name spaces;
  3353 
  3354 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3355 indicate potential overloading;
  3356 
  3357 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3358 
  3359 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3360 "{a,b,c}" instead of {a,b,c};
  3361 
  3362 * Isar/Pure now provides its own version of intro/elim/dest
  3363 attributes; useful for building new logics, but beware of confusion
  3364 with the version in Provers/classical;
  3365 
  3366 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3367 case name 'antecedent';
  3368 
  3369 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3370 to the current context is now done automatically);
  3371 
  3372 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3373 for definining proof methods in ML;
  3374 
  3375 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3376 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3377 most cases, one should have to change intro!! to intro? only);
  3378 replaced "delrule" by "rule del";
  3379 
  3380 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3381 'symmetric' attribute (the latter supercedes [RS sym]);
  3382 
  3383 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3384 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3385 well (including splits);
  3386 
  3387 * Isar/Provers: Simplifier and Classical methods now support all kind
  3388 of modifiers used in the past, including 'cong', 'iff', etc.
  3389 
  3390 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3391 of Simplifier and Classical reasoner);
  3392 
  3393 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3394 now support named cases; major packages (inductive, datatype, primrec,
  3395 recdef) support case names and properly name parameters;
  3396 
  3397 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3398 monotonicity conditions are extracted to be proven at end of
  3399 calculations;
  3400 
  3401 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3402 method anyway;
  3403 
  3404 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3405 split_if split_if_asm; datatype package provides theorems foo.splits =
  3406 foo.split foo.split_asm for each datatype;
  3407 
  3408 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3409 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3410 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3411 use "(cases (simplified))" method in proper proof texts);
  3412 
  3413 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3414 
  3415 * Isar: names of theorems etc. may be natural numbers as well;
  3416 
  3417 * Isar: 'pr' command: optional arguments for goals_limit and
  3418 ProofContext.prems_limit; no longer prints theory contexts, but only
  3419 proof states;
  3420 
  3421 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3422 additional print modes to be specified; e.g. "pr(latex)" will print
  3423 proof state according to the Isabelle LaTeX style;
  3424 
  3425 * Isar: improved support for emulating tactic scripts, including proof
  3426 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3427 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3428 (for HOL datatypes);
  3429 
  3430 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3431 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3432 'proof method scripts' have to be in depth-first order;
  3433 
  3434 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3435 
  3436 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3437 should instead use individual commands for printing items
  3438 (print_commands, print_methods etc.);
  3439 
  3440 * Isar: added 'nothing' --- the empty list of theorems;
  3441 
  3442 
  3443 *** HOL ***
  3444 
  3445 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3446 corresponding virtual machine and a specification of its bytecode
  3447 verifier and a lightweight bytecode verifier, including proofs of
  3448 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3449 Cornelia Pusch (see also the homepage of project Bali at
  3450 http://isabelle.in.tum.de/Bali/);
  3451 
  3452 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3453 Clemens Ballarin;
  3454 
  3455 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3456 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3457 Rasmussen;
  3458 
  3459 * HOL/Lattice: fundamental concepts of lattice theory and order
  3460 structures, including duals, properties of bounds versus algebraic
  3461 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3462 Theorem for complete lattices etc.; may also serve as a demonstration
  3463 for abstract algebraic reasoning using axiomatic type classes, and
  3464 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3465 
  3466 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3467 von Oheimb;
  3468 
  3469 * HOL/IMPP: extension of IMP with local variables and mutually
  3470 recursive procedures, by David von Oheimb;
  3471 
  3472 * HOL/Lambda: converted into new-style theory and document;
  3473 
  3474 * HOL/ex/Multiquote: example of multiple nested quotations and
  3475 anti-quotations -- basically a generalized version of de-Bruijn
  3476 representation; very useful in avoiding lifting of operations;
  3477 
  3478 * HOL/record: added general record equality rule to simpset; fixed
  3479 select-update simplification procedure to handle extended records as
  3480 well; admit "r" as field name;
  3481 
  3482 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3483 other numeric types and also as the identity of groups, rings, etc.;
  3484 
  3485 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3486 Types nat and int belong to this axclass;
  3487 
  3488 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3489    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3490    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3491   two terms #m*u and #n*u are replaced by #(m+n)*u
  3492     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3493   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3494     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3495 
  3496 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3497 powerful prover for predicate logic but knows nothing of clasets; see
  3498 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3499 
  3500 * HOL: new version of "case_tac" subsumes both boolean case split and
  3501 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3502 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3503 
  3504 * HOL: simplification no longer dives into case-expressions: only the
  3505 selector expression is simplified, but not the remaining arms; to
  3506 enable full simplification of case-expressions for datatype t, you may
  3507 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3508 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3509 
  3510 * HOL/recdef: the recursion equations generated by 'recdef' for
  3511 function 'f' are now called f.simps instead of f.rules; if all
  3512 termination conditions are proved automatically, these simplification
  3513 rules are added to the simpset, as in primrec; rules may be named
  3514 individually as well, resulting in a separate list of theorems for
  3515 each equation;
  3516 
  3517 * HOL/While is a new theory that provides a while-combinator. It
  3518 permits the definition of tail-recursive functions without the
  3519 provision of a termination measure. The latter is necessary once the
  3520 invariant proof rule for while is applied.
  3521 
  3522 * HOL: new (overloaded) notation for the set of elements below/above
  3523 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3524 
  3525 * HOL: theorems impI, allI, ballI bound as "strip";
  3526 
  3527 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3528 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3529 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3530 
  3531 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3532 
  3533 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3534 main HOL, but was unused);
  3535 
  3536 * HOL: fewer consts declared as global (e.g. have to refer to
  3537 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3538 
  3539 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3540 in case of overlap with user translations (e.g. judgements over
  3541 tuples); (note that the underlying logical represenation is still
  3542 bogus);
  3543 
  3544 
  3545 *** ZF ***
  3546 
  3547 * ZF: simplification automatically cancels common terms in arithmetic
  3548 expressions over nat and int;
  3549 
  3550 * ZF: new treatment of nat to minimize type-checking: all operators
  3551 coerce their operands to a natural number using the function natify,
  3552 making the algebraic laws unconditional;
  3553 
  3554 * ZF: as above, for int: operators coerce their operands to an integer
  3555 using the function intify;
  3556 
  3557 * ZF: the integer library now contains many of the usual laws for the
  3558 orderings, including $<=, and monotonicity laws for $+ and $*;
  3559 
  3560 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3561 simplification;
  3562 
  3563 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3564 to the simplifier and classical reasoner simultaneously;
  3565 
  3566 
  3567 *** General ***
  3568 
  3569 * Provers: blast_tac now handles actual object-logic rules as
  3570 assumptions; note that auto_tac uses blast_tac internally as well;
  3571 
  3572 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3573 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3574 
  3575 * Provers: delrules now handles destruct rules as well (no longer need
  3576 explicit make_elim);
  3577 
  3578 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3579   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3580 use instead the strong form,
  3581   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3582 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3583 from destruct-rules;
  3584 
  3585 * Provers: Simplifier.easy_setup provides a fast path to basic
  3586 Simplifier setup for new object-logics;
  3587 
  3588 * Pure: AST translation rules no longer require constant head on LHS;
  3589 
  3590 * Pure: improved name spaces: ambiguous output is qualified; support
  3591 for hiding of names;
  3592 
  3593 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3594 XSYMBOL_HOME; no longer need to do manual configuration in most
  3595 situations;
  3596 
  3597 * system: compression of ML heaps images may now be controlled via -c
  3598 option of isabelle and isatool usedir (currently only observed by
  3599 Poly/ML);
  3600 
  3601 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3602 useful for remote X11);
  3603 
  3604 * system: provide TAGS file for Isabelle sources;
  3605 
  3606 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3607 order;
  3608 
  3609 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3610 timing flag supersedes proof_timing and Toplevel.trace;
  3611 
  3612 * ML: new combinators |>> and |>>> for incremental transformations
  3613 with secondary results (e.g. certain theory extensions):
  3614 
  3615 * ML: PureThy.add_defs gets additional argument to indicate potential
  3616 overloading (usually false);
  3617 
  3618 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3619 results;
  3620 
  3621 
  3622 
  3623 New in Isabelle99 (October 1999)
  3624 --------------------------------
  3625 
  3626 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3627 
  3628 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3629 are no longer simplified.  (This allows the simplifier to unfold recursive
  3630 functional programs.)  To restore the old behaviour, declare
  3631 
  3632     Delcongs [if_weak_cong];
  3633 
  3634 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3635 complement;
  3636 
  3637 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3638 
  3639 * HOL/datatype: mutual_induct_tac no longer exists --
  3640   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3641 
  3642 * HOL/typedef: fixed type inference for representing set; type
  3643 arguments now have to occur explicitly on the rhs as type constraints;
  3644 
  3645 * ZF: The con_defs part of an inductive definition may no longer refer
  3646 to constants declared in the same theory;
  3647 
  3648 * HOL, ZF: the function mk_cases, generated by the inductive
  3649 definition package, has lost an argument.  To simplify its result, it
  3650 uses the default simpset instead of a supplied list of theorems.
  3651 
  3652 * HOL/List: the constructors of type list are now Nil and Cons;
  3653 
  3654 * Simplifier: the type of the infix ML functions
  3655         setSSolver addSSolver setSolver addSolver
  3656 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3657 for packaging solvers. A solver is created via
  3658         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3659 where the string argument is only a comment.
  3660 
  3661 
  3662 *** Proof tools ***
  3663 
  3664 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3665 decision procedure for linear arithmetic. Currently it is used for
  3666 types `nat', `int', and `real' in HOL (see below); it can, should and
  3667 will be instantiated for other types and logics as well.
  3668 
  3669 * The simplifier now accepts rewrite rules with flexible heads, eg
  3670      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3671   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3672   matching.
  3673 
  3674 
  3675 *** General ***
  3676 
  3677 * New Isabelle/Isar subsystem provides an alternative to traditional
  3678 tactical theorem proving; together with the ProofGeneral/isar user
  3679 interface it offers an interactive environment for developing human
  3680 readable proof documents (Isar == Intelligible semi-automated
  3681 reasoning); for further information see isatool doc isar-ref,
  3682 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3683 
  3684 * improved and simplified presentation of theories: better HTML markup
  3685 (including colors), graph views in several sizes; isatool usedir now
  3686 provides a proper interface for user theories (via -P option); actual
  3687 document preparation based on (PDF)LaTeX is available as well (for
  3688 new-style theories only); see isatool doc system for more information;
  3689 
  3690 * native support for Proof General, both for classic Isabelle and
  3691 Isabelle/Isar;
  3692 
  3693 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3694 using the graph browser tool;
  3695 
  3696 * Isabelle manuals now also available as PDF;
  3697 
  3698 * theory loader rewritten from scratch (may not be fully
  3699 bug-compatible); old loadpath variable has been replaced by show_path,
  3700 add_path, del_path, reset_path functions; new operations such as
  3701 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3702 isatool doc ref);
  3703 
  3704 * improved isatool install: option -k creates KDE application icon,
  3705 option -p DIR installs standalone binaries;
  3706 
  3707 * added ML_PLATFORM setting (useful for cross-platform installations);
  3708 more robust handling of platform specific ML images for SML/NJ;
  3709 
  3710 * the settings environment is now statically scoped, i.e. it is never
  3711 created again in sub-processes invoked from isabelle, isatool, or
  3712 Isabelle;
  3713 
  3714 * path element specification '~~' refers to '$ISABELLE_HOME';
  3715 
  3716 * in locales, the "assumes" and "defines" parts may be omitted if
  3717 empty;
  3718 
  3719 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3720 long arrows);
  3721 
  3722 * new print_mode "HTML";
  3723 
  3724 * new flag show_tags controls display of tags of theorems (which are
  3725 basically just comments that may be attached by some tools);
  3726 
  3727 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3728 mode and goal output format:
  3729 
  3730 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3731 244c244
  3732 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3733 ---
  3734 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3735 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3736 181c181
  3737 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3738 ---
  3739 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3740 
  3741 * function bind_thms stores lists of theorems (cf. bind_thm);
  3742 
  3743 * new shorthand tactics ftac, eatac, datac, fatac;
  3744 
  3745 * qed (and friends) now accept "" as result name; in that case the
  3746 theorem is not stored, but proper checks and presentation of the
  3747 result still apply;
  3748 
  3749 * theorem database now also indexes constants "Trueprop", "all",
  3750 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3751 
  3752 
  3753 *** HOL ***
  3754 
  3755 ** HOL arithmetic **
  3756 
  3757 * There are now decision procedures for linear arithmetic over nat and
  3758 int:
  3759 
  3760 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3761 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3762 are treated as atomic; subformulae not involving type `nat' or `int'
  3763 are ignored; quantified subformulae are ignored unless they are
  3764 positive universal or negative existential. The tactic has to be
  3765 invoked by hand and can be a little bit slow. In particular, the
  3766 running time is exponential in the number of occurrences of `min' and
  3767 `max', and `-' on `nat'.
  3768 
  3769 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3770 (negated) (in)equalities among the premises and the conclusion into
  3771 account (i.e. no compound formulae) and does not know about `min' and
  3772 `max', and `-' on `nat'. It is fast and is used automatically by the
  3773 simplifier.
  3774 
  3775 NB: At the moment, these decision procedures do not cope with mixed
  3776 nat/int formulae where the two parts interact, such as `m < n ==>
  3777 int(m) < int(n)'.
  3778 
  3779 * HOL/Numeral provides a generic theory of numerals (encoded
  3780 efficiently as bit strings); setup for types nat/int/real is in place;
  3781 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3782 int, existing theories and proof scripts may require a few additional
  3783 type constraints;
  3784 
  3785 * integer division and remainder can now be performed on constant
  3786 arguments;
  3787 
  3788 * many properties of integer multiplication, division and remainder
  3789 are now available;
  3790 
  3791 * An interface to the Stanford Validity Checker (SVC) is available through the
  3792 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3793 are proved automatically.  SVC must be installed separately, and its results
  3794 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3795 invocation of the underlying oracle).  For SVC see
  3796   http://verify.stanford.edu/SVC
  3797 
  3798 * IsaMakefile: the HOL-Real target now builds an actual image;
  3799 
  3800 
  3801 ** HOL misc **
  3802 
  3803 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3804 (in Isabelle/Isar) -- by Gertrud Bauer;
  3805 
  3806 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3807 analysis for assembly languages with subtypes;
  3808 
  3809 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3810 -- avoids syntactic ambiguities and treats state, transition, and
  3811 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3812 changed syntax and (many) tactics;
  3813 
  3814 * HOL/inductive: Now also handles more general introduction rules such
  3815   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3816   theorems are now maintained within the theory (maintained via the
  3817   "mono" attribute);
  3818 
  3819 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3820   (using function types) such as
  3821 
  3822   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3823 
  3824 * HOL/record: record_simproc (part of the default simpset) takes care
  3825 of selectors applied to updated records; record_split_tac is no longer
  3826 part of the default claset; update_defs may now be removed from the
  3827 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3828 
  3829   claset_ref () := claset() addSWrapper record_split_wrapper;
  3830   Delsimprocs [record_simproc]
  3831 
  3832 * HOL/typedef: fixed type inference for representing set; type
  3833 arguments now have to occur explicitly on the rhs as type constraints;
  3834 
  3835 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3836 names rather than an ML expression;
  3837 
  3838 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3839 supplied later.  Program schemes can be defined, such as
  3840     "While B C s = (if B s then While B C (C s) else s)"
  3841 where the well-founded relation can be chosen after B and C have been given.
  3842 
  3843 * HOL/List: the constructors of type list are now Nil and Cons;
  3844 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3845 course, ML tools referring to List.list.op # etc. have to be adapted;
  3846 
  3847 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3848 disabled by default; run isabelle with option -m HOL to get back to
  3849 the original Gordon/HOL-style output;
  3850 
  3851 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3852 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3853 
  3854 * HOL basic syntax simplified (more orthogonal): all variants of
  3855 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3856 Eps operator is provided as well: "SOME x. P[x]";
  3857 
  3858 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3859 
  3860 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3861 thus available for user theories;
  3862 
  3863 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3864 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3865 time;
  3866 
  3867 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3868 several times and then mp;
  3869 
  3870 
  3871 *** LK ***
  3872 
  3873 * the notation <<...>> is now available as a notation for sequences of
  3874 formulas;
  3875 
  3876 * the simplifier is now installed
  3877 
  3878 * the axiom system has been generalized (thanks to Soren Heilmann)
  3879 
  3880 * the classical reasoner now has a default rule database
  3881 
  3882 
  3883 *** ZF ***
  3884 
  3885 * new primrec section allows primitive recursive functions to be given
  3886 directly (as in HOL) over datatypes and the natural numbers;
  3887 
  3888 * new tactics induct_tac and exhaust_tac for induction (or case
  3889 analysis) over datatypes and the natural numbers;
  3890 
  3891 * the datatype declaration of type T now defines the recursor T_rec;
  3892 
  3893 * simplification automatically does freeness reasoning for datatype
  3894 constructors;
  3895 
  3896 * automatic type-inference, with AddTCs command to insert new
  3897 type-checking rules;
  3898 
  3899 * datatype introduction rules are now added as Safe Introduction rules
  3900 to the claset;
  3901 
  3902 * the syntax "if P then x else y" is now available in addition to
  3903 if(P,x,y);
  3904 
  3905 
  3906 *** Internal programming interfaces ***
  3907 
  3908 * tuned simplifier trace output; new flag debug_simp;
  3909 
  3910 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3911 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3912 
  3913 * AxClass.axclass_tac lost the theory argument;
  3914 
  3915 * tuned current_goals_markers semantics: begin / end goal avoids
  3916 printing empty lines;
  3917 
  3918 * removed prs and prs_fn hook, which was broken because it did not
  3919 include \n in its semantics, forcing writeln to add one
  3920 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3921 string -> unit if you really want to output text without newline;
  3922 
  3923 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3924 plain output, interface builders may have to enable 'isabelle_font'
  3925 mode to get Isabelle font glyphs as before;
  3926 
  3927 * refined token_translation interface; INCOMPATIBILITY: output length
  3928 now of type real instead of int;
  3929 
  3930 * theory loader actions may be traced via new ThyInfo.add_hook
  3931 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3932 your own database of information attached to *whole* theories -- as
  3933 opposed to intra-theory data slots offered via TheoryDataFun;
  3934 
  3935 * proper handling of dangling sort hypotheses (at last!);
  3936 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3937 extra sort hypotheses that can be witnessed from the type signature;
  3938 the force_strip_shyps flag is gone, any remaining shyps are simply
  3939 left in the theorem (with a warning issued by strip_shyps_warning);
  3940 
  3941 
  3942 
  3943 New in Isabelle98-1 (October 1998)
  3944 ----------------------------------
  3945 
  3946 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3947 
  3948 * several changes of automated proof tools;
  3949 
  3950 * HOL: major changes to the inductive and datatype packages, including
  3951 some minor incompatibilities of theory syntax;
  3952 
  3953 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3954 called `inj_on';
  3955 
  3956 * HOL: removed duplicate thms in Arith:
  3957   less_imp_add_less  should be replaced by  trans_less_add1
  3958   le_imp_add_le      should be replaced by  trans_le_add1
  3959 
  3960 * HOL: unary minus is now overloaded (new type constraints may be
  3961 required);
  3962 
  3963 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3964 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3965 now taken as an integer constant.
  3966 
  3967 * Pure: ML function 'theory_of' renamed to 'theory';
  3968 
  3969 
  3970 *** Proof tools ***
  3971 
  3972 * Simplifier:
  3973   1. Asm_full_simp_tac is now more aggressive.
  3974      1. It will sometimes reorient premises if that increases their power to
  3975         simplify.
  3976      2. It does no longer proceed strictly from left to right but may also
  3977         rotate premises to achieve further simplification.
  3978      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3979      old Asm_full_simp_tac in that it does not rotate premises.
  3980   2. The simplifier now knows a little bit about nat-arithmetic.
  3981 
  3982 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3983 allows for selected deletion of wrappers, by introduction of names for
  3984 wrapper functionals.  This implies that addbefore, addSbefore,
  3985 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3986 and that adding two tactics with the same name overwrites the first
  3987 one (emitting a warning).
  3988   type wrapper = (int -> tactic) -> (int -> tactic)
  3989   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3990   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3991   delWrapper, delSWrapper: claset *  string            -> claset
  3992   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3993 
  3994 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3995 semantics; addbefore now affects only the unsafe part of step_tac
  3996 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3997 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3998 by Force_tac;
  3999 
  4000 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4001 compWrapper; added safe wrapper (and access functions for it);
  4002 
  4003 * HOL/split_all_tac is now much faster and fails if there is nothing
  4004 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4005 and the names of the automatically generated variables have changed.
  4006 split_all_tac has moved within claset() from unsafe wrappers to safe
  4007 wrappers, which means that !!-bound variables are split much more
  4008 aggressively, and safe_tac and clarify_tac now split such variables.
  4009 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4010 Note: the same holds for record_split_tac, which does the job of
  4011 split_all_tac for record fields.
  4012 
  4013 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4014 permanently to the default simpset using Addsplits just like
  4015 Addsimps. They can be removed via Delsplits just like
  4016 Delsimps. Lower-case versions are also available.
  4017 
  4018 * HOL/Simplifier: The rule split_if is now part of the default
  4019 simpset. This means that the simplifier will eliminate all occurrences
  4020 of if-then-else in the conclusion of a goal. To prevent this, you can
  4021 either remove split_if completely from the default simpset by
  4022 `Delsplits [split_if]' or remove it in a specific call of the
  4023 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4024 other case splitting rules to/from the default simpset: every datatype
  4025 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4026 t is the name of the datatype).
  4027 
  4028 * Classical reasoner / Simplifier combination: new force_tac (and
  4029 derivatives Force_tac, force) combines rewriting and classical
  4030 reasoning (and whatever other tools) similarly to auto_tac, but is
  4031 aimed to solve the given subgoal completely.
  4032 
  4033 
  4034 *** General ***
  4035 
  4036 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4037 and `goalw': the theory is no longer needed as an explicit argument -
  4038 the current theory context is used; assumptions are no longer returned
  4039 at the ML-level unless one of them starts with ==> or !!; it is
  4040 recommended to convert to these new commands using isatool fixgoal
  4041 (backup your sources first!);
  4042 
  4043 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4044 the current theory context, and 'theory' to lookup stored theories;
  4045 
  4046 * new theory section 'locale' for declaring constants, assumptions and
  4047 definitions that have local scope;
  4048 
  4049 * new theory section 'nonterminals' for purely syntactic types;
  4050 
  4051 * new theory section 'setup' for generic ML setup functions
  4052 (e.g. package initialization);
  4053 
  4054 * the distribution now includes Isabelle icons: see
  4055 lib/logo/isabelle-{small,tiny}.xpm;
  4056 
  4057 * isatool install - install binaries with absolute references to
  4058 ISABELLE_HOME/bin;
  4059 
  4060 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4061 
  4062 * print mode 'emacs' reserved for Isamode;
  4063 
  4064 * support multiple print (ast) translations per constant name;
  4065 
  4066 * theorems involving oracles are now printed with a suffixed [!];
  4067 
  4068 
  4069 *** HOL ***
  4070 
  4071 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4072 
  4073 * HOL/inductive package reorganized and improved: now supports mutual
  4074 definitions such as
  4075 
  4076   inductive EVEN ODD
  4077     intrs
  4078       null "0 : EVEN"
  4079       oddI "n : EVEN ==> Suc n : ODD"
  4080       evenI "n : ODD ==> Suc n : EVEN"
  4081 
  4082 new theorem list "elims" contains an elimination rule for each of the
  4083 recursive sets; inductive definitions now handle disjunctive premises
  4084 correctly (also ZF);
  4085 
  4086 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4087 "mutual_induct" no longer exists - the induction rule is always
  4088 contained in "induct";
  4089 
  4090 
  4091 * HOL/datatype package re-implemented and greatly improved: now
  4092 supports mutually recursive datatypes such as
  4093 
  4094   datatype
  4095     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4096             | SUM ('a aexp) ('a aexp)
  4097             | DIFF ('a aexp) ('a aexp)
  4098             | NUM 'a
  4099   and
  4100     'a bexp = LESS ('a aexp) ('a aexp)
  4101             | AND ('a bexp) ('a bexp)
  4102             | OR ('a bexp) ('a bexp)
  4103 
  4104 as well as indirectly recursive datatypes such as
  4105 
  4106   datatype
  4107     ('a, 'b) term = Var 'a
  4108                   | App 'b ((('a, 'b) term) list)
  4109 
  4110 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4111 induction on mutually / indirectly recursive datatypes.
  4112 
  4113 Primrec equations are now stored in theory and can be accessed via
  4114 <function_name>.simps.
  4115 
  4116 INCOMPATIBILITIES:
  4117 
  4118   - Theories using datatypes must now have theory Datatype as an
  4119     ancestor.
  4120   - The specific <typename>.induct_tac no longer exists - use the
  4121     generic induct_tac instead.
  4122   - natE has been renamed to nat.exhaust - use exhaust_tac
  4123     instead of res_inst_tac ... natE. Note that the variable
  4124     names in nat.exhaust differ from the names in natE, this
  4125     may cause some "fragile" proofs to fail.
  4126   - The theorems split_<typename>_case and split_<typename>_case_asm
  4127     have been renamed to <typename>.split and <typename>.split_asm.
  4128   - Since default sorts of type variables are now handled correctly,
  4129     some datatype definitions may have to be annotated with explicit
  4130     sort constraints.
  4131   - Primrec definitions no longer require function name and type
  4132     of recursive argument.
  4133 
  4134 Consider using isatool fixdatatype to adapt your theories and proof
  4135 scripts to the new package (backup your sources first!).
  4136 
  4137 
  4138 * HOL/record package: considerably improved implementation; now
  4139 includes concrete syntax for record types, terms, updates; theorems
  4140 for surjective pairing and splitting !!-bound record variables; proof
  4141 support is as follows:
  4142 
  4143   1) standard conversions (selectors or updates applied to record
  4144 constructor terms) are part of the standard simpset;
  4145 
  4146   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4147 made part of standard simpset and claset via addIffs;
  4148 
  4149   3) a tactic for record field splitting (record_split_tac) is part of
  4150 the standard claset (addSWrapper);
  4151 
  4152 To get a better idea about these rules you may retrieve them via
  4153 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4154 the name of your record type.
  4155 
  4156 The split tactic 3) conceptually simplifies by the following rule:
  4157 
  4158   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4159 
  4160 Thus any record variable that is bound by meta-all will automatically
  4161 blow up into some record constructor term, consequently the
  4162 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4163 solve record problems automatically.
  4164 
  4165 
  4166 * reorganized the main HOL image: HOL/Integ and String loaded by
  4167 default; theory Main includes everything;
  4168 
  4169 * automatic simplification of integer sums and comparisons, using cancellation;
  4170 
  4171 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4172 
  4173 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4174 
  4175 * many new identities for unions, intersections, set difference, etc.;
  4176 
  4177 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4178 called split_if, split_split, split_sum_case and split_nat_case (to go
  4179 with add/delsplits);
  4180 
  4181 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4182 (?x::unit) = (); this is made part of the default simpset, which COULD
  4183 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4184 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4185 unit_abs_eta_conv is added in order to counter the effect of
  4186 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4187 %u.f();
  4188 
  4189 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4190 makes more sense);
  4191 
  4192 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4193   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4194   disjointness reasoning but breaking a few old proofs.
  4195 
  4196 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4197 to 'converse' from 'inverse' (for compatibility with ZF and some
  4198 literature);
  4199 
  4200 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4201 the well-founded relation;
  4202 
  4203 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4204     Compl A.  The "Compl" syntax remains available as input syntax for this
  4205     release ONLY.
  4206 
  4207 * HOL/Update: new theory of function updates:
  4208     f(a:=b) == %x. if x=a then b else f x
  4209 may also be iterated as in f(a:=b,c:=d,...);
  4210 
  4211 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4212 
  4213 * HOL/List:
  4214   - new function list_update written xs[i:=v] that updates the i-th
  4215     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4216   - new function `upt' written [i..j(] which generates the list
  4217     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4218     bound write [i..j], which is a shorthand for [i..j+1(].
  4219   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4220 
  4221 * HOL/Arith:
  4222   - removed 'pred' (predecessor) function;
  4223   - generalized some theorems about n-1;
  4224   - many new laws about "div" and "mod";
  4225   - new laws about greatest common divisors (see theory ex/Primes);
  4226 
  4227 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4228 instead of "inverse";
  4229 
  4230 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4231   of the multiset ordering;
  4232 
  4233 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4234   (not included by default);
  4235 
  4236 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4237 
  4238 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4239   programs, i.e. different program variables may have different types.
  4240 
  4241 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4242   [previously, this check worked only if the rewrite rule was unconditional]
  4243   Now rew can involve either definitions or equalities (either == or =).
  4244 
  4245 
  4246 *** ZF ***
  4247 
  4248 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4249   only the theorems proved on ZF.ML;
  4250 
  4251 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4252   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4253   disjointness reasoning but breaking a few old proofs.
  4254 
  4255 * ZF/Update: new theory of function updates
  4256     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4257   may also be iterated as in f(a:=b,c:=d,...);
  4258 
  4259 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4260 
  4261 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4262   [previously, this check worked only if the rewrite rule was unconditional]
  4263   Now rew can involve either definitions or equalities (either == or =).
  4264 
  4265 * case_tac provided for compatibility with HOL
  4266     (like the old excluded_middle_tac, but with subgoals swapped)
  4267 
  4268 
  4269 *** Internal programming interfaces ***
  4270 
  4271 * Pure: several new basic modules made available for general use, see
  4272 also src/Pure/README;
  4273 
  4274 * improved the theory data mechanism to support encapsulation (data
  4275 kind name replaced by private Object.kind, acting as authorization
  4276 key); new type-safe user interface via functor TheoryDataFun; generic
  4277 print_data function becomes basically useless;
  4278 
  4279 * removed global_names compatibility flag -- all theory declarations
  4280 are qualified by default;
  4281 
  4282 * module Pure/Syntax now offers quote / antiquote translation
  4283 functions (useful for Hoare logic etc. with implicit dependencies);
  4284 see HOL/ex/Antiquote for an example use;
  4285 
  4286 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4287 cterm -> thm;
  4288 
  4289 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4290 subgoal;
  4291 
  4292 * Display.print_goals function moved to Locale.print_goals;
  4293 
  4294 * standard print function for goals supports current_goals_markers
  4295 variable for marking begin of proof, end of proof, start of goal; the
  4296 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4297 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4298 for example;
  4299 
  4300 
  4301 
  4302 New in Isabelle98 (January 1998)
  4303 --------------------------------
  4304 
  4305 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4306 
  4307 * changed lexical syntax of terms / types: dots made part of long
  4308 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4309 
  4310 * simpset (and claset) reference variable replaced by functions
  4311 simpset / simpset_ref;
  4312 
  4313 * no longer supports theory aliases (via merge) and non-trivial
  4314 implicit merge of thms' signatures;
  4315 
  4316 * most internal names of constants changed due to qualified names;
  4317 
  4318 * changed Pure/Sequence interface (see Pure/seq.ML);
  4319 
  4320 
  4321 *** General Changes ***
  4322 
  4323 * hierachically structured name spaces (for consts, types, axms, thms
  4324 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4325 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4326 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4327 long_names for fully qualified output names; NOTE: ML programs
  4328 (special tactics, packages etc.) referring to internal names may have
  4329 to be adapted to cope with fully qualified names; in case of severe
  4330 backward campatibility problems try setting 'global_names' at compile
  4331 time to have enrything declared within a flat name space; one may also
  4332 fine tune name declarations in theories via the 'global' and 'local'
  4333 section;
  4334 
  4335 * reimplemented the implicit simpset and claset using the new anytype
  4336 data filed in signatures; references simpset:simpset ref etc. are
  4337 replaced by functions simpset:unit->simpset and
  4338 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4339 to patch your ML files accordingly;
  4340 
  4341 * HTML output now includes theory graph data for display with Java
  4342 applet or isatool browser; data generated automatically via isatool
  4343 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4344 
  4345 * defs may now be conditional; improved rewrite_goals_tac to handle
  4346 conditional equations;
  4347 
  4348 * defs now admits additional type arguments, using TYPE('a) syntax;
  4349 
  4350 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4351 creates a new theory node; implicit merge of thms' signatures is
  4352 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4353 transfer:theory->thm->thm in (rare) cases;
  4354 
  4355 * improved handling of draft signatures / theories; draft thms (and
  4356 ctyps, cterms) are automatically promoted to real ones;
  4357 
  4358 * slightly changed interfaces for oracles: admit many per theory, named
  4359 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4360 
  4361 * print_goals: optional output of const types (set show_consts and
  4362 show_types);
  4363 
  4364 * improved output of warnings (###) and errors (***);
  4365 
  4366 * subgoal_tac displays a warning if the new subgoal has type variables;
  4367 
  4368 * removed old README and Makefiles;
  4369 
  4370 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4371 
  4372 * removed obsolete init_pps and init_database;
  4373 
  4374 * deleted the obsolete tactical STATE, which was declared by
  4375     fun STATE tacfun st = tacfun st st;
  4376 
  4377 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4378 (which abbreviates $HOME);
  4379 
  4380 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4381 use isatool fixseq to adapt your ML programs (this works for fully
  4382 qualified references to the Sequence structure only!);
  4383 
  4384 * use_thy no longer requires writable current directory; it always
  4385 reloads .ML *and* .thy file, if either one is out of date;
  4386 
  4387 
  4388 *** Classical Reasoner ***
  4389 
  4390 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4391 tactics that use classical reasoning to simplify a subgoal without
  4392 splitting it into several subgoals;
  4393 
  4394 * Safe_tac: like safe_tac but uses the default claset;
  4395 
  4396 
  4397 *** Simplifier ***
  4398 
  4399 * added simplification meta rules:
  4400     (asm_)(full_)simplify: simpset -> thm -> thm;
  4401 
  4402 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4403 logics (again);
  4404 
  4405 * added prems argument to simplification procedures;
  4406 
  4407 * HOL, FOL, ZF: added infix function `addsplits':
  4408   instead of `<simpset> setloop (split_tac <thms>)'
  4409   you can simply write `<simpset> addsplits <thms>'
  4410 
  4411 
  4412 *** Syntax ***
  4413 
  4414 * TYPE('a) syntax for type reflection terms;
  4415 
  4416 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4417 
  4418 * pretty printer: changed order of mixfix annotation preference (again!);
  4419 
  4420 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4421 
  4422 
  4423 *** HOL ***
  4424 
  4425 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4426   with `addloop' of the simplifier to faciliate case splitting in premises.
  4427 
  4428 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4429 
  4430 * HOL/Auth: new protocol proofs including some for the Internet
  4431   protocol TLS;
  4432 
  4433 * HOL/Map: new theory of `maps' a la VDM;
  4434 
  4435 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4436 cancelling out common nat summands from =, <, <= (in)equalities, or
  4437 differences; simplification procedures nat_cancel_factor for
  4438 cancelling common factor from =, <, <= (in)equalities over natural
  4439 sums; nat_cancel contains both kinds of procedures, it is installed by
  4440 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4441 
  4442 * HOL/simplifier: terms of the form
  4443   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4444   are rewritten to
  4445   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4446   and those of the form
  4447   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4448   are rewritten to
  4449   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4450 
  4451 * HOL/datatype
  4452   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4453 
  4454   P(t_case f1 ... fn x) =
  4455      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4456         ...
  4457        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4458      )
  4459 
  4460   and a theorem `split_t_case_asm' of the form
  4461 
  4462   P(t_case f1 ... fn x) =
  4463     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4464         ...
  4465        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4466      )
  4467   which can be added to a simpset via `addsplits'. The existing theorems
  4468   expand_list_case and expand_option_case have been renamed to
  4469   split_list_case and split_option_case.
  4470 
  4471 * HOL/Arithmetic:
  4472   - `pred n' is automatically converted to `n-1'.
  4473     Users are strongly encouraged not to use `pred' any longer,
  4474     because it will disappear altogether at some point.
  4475   - Users are strongly encouraged to write "0 < n" rather than
  4476     "n ~= 0". Theorems and proof tools have been modified towards this
  4477     `standard'.
  4478 
  4479 * HOL/Lists:
  4480   the function "set_of_list" has been renamed "set" (and its theorems too);
  4481   the function "nth" now takes its arguments in the reverse order and
  4482   has acquired the infix notation "!" as in "xs!n".
  4483 
  4484 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4485 
  4486 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4487   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4488 
  4489 * HOL/record: extensible records with schematic structural subtyping
  4490 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4491 still lacks various theorems and concrete record syntax;
  4492 
  4493 
  4494 *** HOLCF ***
  4495 
  4496 * removed "axioms" and "generated by" sections;
  4497 
  4498 * replaced "ops" section by extended "consts" section, which is capable of
  4499   handling the continuous function space "->" directly;
  4500 
  4501 * domain package:
  4502   . proves theorems immediately and stores them in the theory,
  4503   . creates hierachical name space,
  4504   . now uses normal mixfix annotations (instead of cinfix...),
  4505   . minor changes to some names and values (for consistency),
  4506   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4507   . separator between mutual domain defs: changed "," to "and",
  4508   . improved handling of sort constraints;  now they have to
  4509     appear on the left-hand side of the equations only;
  4510 
  4511 * fixed LAM <x,y,zs>.b syntax;
  4512 
  4513 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4514 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4515 
  4516 
  4517 *** FOL and ZF ***
  4518 
  4519 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4520   with `addloop' of the simplifier to faciliate case splitting in premises.
  4521 
  4522 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4523 in HOL, they strip ALL and --> from proved theorems;
  4524 
  4525 
  4526 
  4527 New in Isabelle94-8 (May 1997)
  4528 ------------------------------
  4529 
  4530 *** General Changes ***
  4531 
  4532 * new utilities to build / run / maintain Isabelle etc. (in parts
  4533 still somewhat experimental); old Makefiles etc. still functional;
  4534 
  4535 * new 'Isabelle System Manual';
  4536 
  4537 * INSTALL text, together with ./configure and ./build scripts;
  4538 
  4539 * reimplemented type inference for greater efficiency, better error
  4540 messages and clean internal interface;
  4541 
  4542 * prlim command for dealing with lots of subgoals (an easier way of
  4543 setting goals_limit);
  4544 
  4545 
  4546 *** Syntax ***
  4547 
  4548 * supports alternative (named) syntax tables (parser and pretty
  4549 printer); internal interface is provided by add_modesyntax(_i);
  4550 
  4551 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4552 be used in conjunction with the Isabelle symbol font; uses the
  4553 "symbols" syntax table;
  4554 
  4555 * added token_translation interface (may translate name tokens in
  4556 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4557 the current print_mode); IMPORTANT: user print translation functions
  4558 are responsible for marking newly introduced bounds
  4559 (Syntax.mark_boundT);
  4560 
  4561 * token translations for modes "xterm" and "xterm_color" that display
  4562 names in bold, underline etc. or colors (which requires a color
  4563 version of xterm);
  4564 
  4565 * infixes may now be declared with names independent of their syntax;
  4566 
  4567 * added typed_print_translation (like print_translation, but may
  4568 access type of constant);
  4569 
  4570 
  4571 *** Classical Reasoner ***
  4572 
  4573 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4574 some limitations.  Blast_tac...
  4575   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4576   + ignores elimination rules that don't have the correct format
  4577         (the conclusion MUST be a formula variable)
  4578   + ignores types, which can make HOL proofs fail
  4579   + rules must not require higher-order unification, e.g. apply_type in ZF
  4580     [message "Function Var's argument not a bound variable" relates to this]
  4581   + its proof strategy is more general but can actually be slower
  4582 
  4583 * substitution with equality assumptions no longer permutes other
  4584 assumptions;
  4585 
  4586 * minor changes in semantics of addafter (now called addaltern); renamed
  4587 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4588 (and access functions for it);
  4589 
  4590 * improved combination of classical reasoner and simplifier:
  4591   + functions for handling clasimpsets
  4592   + improvement of addss: now the simplifier is called _after_ the
  4593     safe steps.
  4594   + safe variant of addss called addSss: uses safe simplifications
  4595     _during_ the safe steps. It is more complete as it allows multiple
  4596     instantiations of unknowns (e.g. with slow_tac).
  4597 
  4598 *** Simplifier ***
  4599 
  4600 * added interface for simplification procedures (functions that
  4601 produce *proven* rewrite rules on the fly, depending on current
  4602 redex);
  4603 
  4604 * ordering on terms as parameter (used for ordered rewriting);
  4605 
  4606 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4607 
  4608 * the solver is now split into a safe and an unsafe part.
  4609 This should be invisible for the normal user, except that the
  4610 functions setsolver and addsolver have been renamed to setSolver and
  4611 addSolver; added safe_asm_full_simp_tac;
  4612 
  4613 
  4614 *** HOL ***
  4615 
  4616 * a generic induction tactic `induct_tac' which works for all datatypes and
  4617 also for type `nat';
  4618 
  4619 * a generic case distinction tactic `exhaust_tac' which works for all
  4620 datatypes and also for type `nat';
  4621 
  4622 * each datatype comes with a function `size';
  4623 
  4624 * patterns in case expressions allow tuple patterns as arguments to
  4625 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4626 
  4627 * primrec now also works with type nat;
  4628 
  4629 * recdef: a new declaration form, allows general recursive functions to be
  4630 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4631 
  4632 * the constant for negation has been renamed from "not" to "Not" to
  4633 harmonize with FOL, ZF, LK, etc.;
  4634 
  4635 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4636 infinite lists;
  4637 
  4638 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4639 
  4640 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4641 problems in commutative rings, using axiomatic type classes for + and *;
  4642 
  4643 * more examples in HOL/MiniML and HOL/Auth;
  4644 
  4645 * more default rewrite rules for quantifiers, union/intersection;
  4646 
  4647 * a new constant `arbitrary == @x.False';
  4648 
  4649 * HOLCF/IOA replaces old HOL/IOA;
  4650 
  4651 * HOLCF changes: derived all rules and arities
  4652   + axiomatic type classes instead of classes
  4653   + typedef instead of faking type definitions
  4654   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4655   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4656   + eliminated the types void, one, tr
  4657   + use unit lift and bool lift (with translations) instead of one and tr
  4658   + eliminated blift from Lift3.thy (use Def instead of blift)
  4659   all eliminated rules are derived as theorems --> no visible changes ;
  4660 
  4661 
  4662 *** ZF ***
  4663 
  4664 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4665 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4666 as ZF_cs addSIs [equalityI];
  4667 
  4668 
  4669 
  4670 New in Isabelle94-7 (November 96)
  4671 ---------------------------------
  4672 
  4673 * allowing negative levels (as offsets) in prlev and choplev;
  4674 
  4675 * super-linear speedup for large simplifications;
  4676 
  4677 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4678 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4679 FAIL); can suppress it using the command Delsimps (ex_simps @
  4680 all_simps); De Morgan laws are also now included, by default;
  4681 
  4682 * improved printing of ==>  :  ~:
  4683 
  4684 * new object-logic "Sequents" adds linear logic, while replacing LK
  4685 and Modal (thanks to Sara Kalvala);
  4686 
  4687 * HOL/Auth: correctness proofs for authentication protocols;
  4688 
  4689 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4690 examples on HOL/Auth);
  4691 
  4692 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4693 the rewriter and classical reasoner simultaneously;
  4694 
  4695 * function uresult no longer returns theorems in "standard" format;
  4696 regain previous version by: val uresult = standard o uresult;
  4697 
  4698 
  4699 
  4700 New in Isabelle94-6
  4701 -------------------
  4702 
  4703 * oracles -- these establish an interface between Isabelle and trusted
  4704 external reasoners, which may deliver results as theorems;
  4705 
  4706 * proof objects (in particular record all uses of oracles);
  4707 
  4708 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4709 
  4710 * "constdefs" section in theory files;
  4711 
  4712 * "primrec" section (HOL) no longer requires names;
  4713 
  4714 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4715 
  4716 
  4717 
  4718 New in Isabelle94-5
  4719 -------------------
  4720 
  4721 * reduced space requirements;
  4722 
  4723 * automatic HTML generation from theories;
  4724 
  4725 * theory files no longer require "..." (quotes) around most types;
  4726 
  4727 * new examples, including two proofs of the Church-Rosser theorem;
  4728 
  4729 * non-curried (1994) version of HOL is no longer distributed;
  4730 
  4731 
  4732 
  4733 New in Isabelle94-4
  4734 -------------------
  4735 
  4736 * greatly reduced space requirements;
  4737 
  4738 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4739 
  4740 * searchable theorem database (see the section "Retrieving theorems" on
  4741 page 8 of the Reference Manual);
  4742 
  4743 * new examples, including Grabczewski's monumental case study of the
  4744 Axiom of Choice;
  4745 
  4746 * The previous version of HOL renamed to Old_HOL;
  4747 
  4748 * The new version of HOL (previously called CHOL) uses a curried syntax
  4749 for functions.  Application looks like f a b instead of f(a,b);
  4750 
  4751 * Mutually recursive inductive definitions finally work in HOL;
  4752 
  4753 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4754 translates to the operator "split";
  4755 
  4756 
  4757 
  4758 New in Isabelle94-3
  4759 -------------------
  4760 
  4761 * new infix operator, addss, allowing the classical reasoner to
  4762 perform simplification at each step of its search.  Example:
  4763         fast_tac (cs addss ss)
  4764 
  4765 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4766 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4767 look like (a,b) instead of <a,b>;
  4768 
  4769 * PLEASE NOTE: CHOL will eventually replace HOL!
  4770 
  4771 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4772 It translates to the operator "split".  A new theory of integers is available;
  4773 
  4774 * In ZF, integer numerals now denote two's-complement binary integers.
  4775 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4776 
  4777 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4778 of the Axiom of Choice;
  4779 
  4780 
  4781 
  4782 New in Isabelle94-2
  4783 -------------------
  4784 
  4785 * Significantly faster resolution;
  4786 
  4787 * the different sections in a .thy file can now be mixed and repeated
  4788 freely;
  4789 
  4790 * Database of theorems for FOL, HOL and ZF.  New
  4791 commands including qed, qed_goal and bind_thm store theorems in the database.
  4792 
  4793 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4794 a given theory (thms_of), or find out what theory a theorem was proved in
  4795 (theory_of_thm);
  4796 
  4797 * Bugs fixed in the inductive definition and datatype packages;
  4798 
  4799 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4800 and HOL_dup_cs obsolete;
  4801 
  4802 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4803 have been removed;
  4804 
  4805 * Simpler definition of function space in ZF;
  4806 
  4807 * new results about cardinal and ordinal arithmetic in ZF;
  4808 
  4809 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4810 types;
  4811 
  4812 
  4813 $Id$