NEWS
author wenzelm
Fri Jan 19 22:31:17 2007 +0100 (2007-01-19)
changeset 22126 420b7b102acc
parent 22125 cc35c948f6c5
child 22138 b9cbcd8be40f
permissions -rw-r--r--
tuned;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: some popular names (e.g. "class", "fun", "help",
    19 "if") are now keywords.  INCOMPATIBILITY, use double quotes.
    20 
    21 * Legacy goal package: reduced interface to the bare minimum required
    22 to keep existing proof scripts running.  Most other user-level
    23 functions are now part of the OldGoals structure, which is *not* open
    24 by default (consider isatool expandshort before open OldGoals).
    25 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    26 these tend to cause confusion about the actual goal (!) context being
    27 used here, which is not necessarily the same as the_context().
    28 
    29 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    30 
    31 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    32 by default, which means that "prems" (and also "fixed variables") are
    33 suppressed from proof state output.  Note that the ProofGeneral
    34 settings mechanism allows to change and save options persistently, but
    35 older versions of Isabelle will fail to start up if a negative prems
    36 limit is imposed.
    37 
    38 * Local theory targets may be specified by non-nested blocks of
    39 ``context/locale/class ... begin'' followed by ``end''.  The body may
    40 contain definitions, theorems etc., including any derived mechanism
    41 that has been implemented on top of these primitives.  This concept
    42 generalizes the existing ``theorem (in ...)'' towards more versatility
    43 and scalability.
    44 
    45 * Proof General interface: proper undo of final 'end' command;
    46 discontinued Isabelle/classic mode (ML proof scripts).
    47 
    48 
    49 *** Document preparation ***
    50 
    51 * Added antiquotation @{theory name} which prints the given name,
    52 after checking that it refers to a valid ancestor theory in the
    53 current context.
    54 
    55 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    56 check the given source text as ML type/structure, printing verbatim.
    57 
    58 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    59 "c args == rhs" given in the current context.  (Any number of
    60 arguments may be given on the LHS.)
    61 
    62 
    63 
    64 *** Pure ***
    65 
    66 * class_package.ML offers a combination of axclasses and locales to
    67 achieve Haskell-like type classes in Isabelle. See
    68 HOL/ex/Classpackage.thy for examples.
    69 
    70 * Yet another code generator framework allows to generate executable
    71 code for ML and Haskell (including "class"es). A short usage sketch:
    72 
    73     internal compilation:
    74         code_gen <list of constants (term syntax)> (SML #)
    75     writing SML code to a file:
    76         code_gen <list of constants (term syntax)> (SML <filename>)
    77     writing Haskell code to a bunch of files:
    78         code_gen <list of constants (term syntax)> (Haskell <filename>)
    79 
    80 Reasonable default setup of framework in HOL/Main.
    81 
    82 See HOL/ex/Code*.thy for examples.
    83 
    84 Theorem attributs for selecting and transforming function equations theorems:
    85 
    86     [code fun]:       select a theorem as function equation for a specific constant
    87     [code nofun]:     deselect a theorem as function equation for a specific constant
    88     [code inline]:    select an equation theorem for unfolding (inlining) in place
    89     [code noinline]:  deselect an equation theorem for unfolding (inlining) in place
    90 
    91 User-defined serializations (target in {SML, Haskell}):
    92 
    93     code_const <and-list of constants (term syntax)>
    94       {(target) <and-list of const target syntax>}+
    95 
    96     code_type <and-list of type constructors>
    97       {(target) <and-list of type target syntax>}+
    98 
    99     code_instance <and-list of instances>
   100       {(target)}+
   101         where instance ::= <type constructor> :: <class>
   102 
   103     code_class <and_list of classes>
   104       {(target) <and-list of class target syntax>}+
   105         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   106 
   107 For code_instance and code_class, target SML is silently ignored.
   108 
   109 See HOL theories and HOL/ex/Code*.thy for usage examples.  Doc/Isar/Advanced/Codegen/
   110 provides a tutorial.
   111 
   112 * Command 'no_translations' removes translation rules from theory
   113 syntax.
   114 
   115 * Overloaded definitions are now actually checked for acyclic
   116 dependencies.  The overloading scheme is slightly more general than
   117 that of Haskell98, although Isabelle does not demand an exact
   118 correspondence to type class and instance declarations.
   119 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   120 exotic versions of overloading -- at the discretion of the user!
   121 
   122 Polymorphic constants are represented via type arguments, i.e. the
   123 instantiation that matches an instance against the most general
   124 declaration given in the signature.  For example, with the declaration
   125 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   126 as c(nat).  Overloading is essentially simultaneous structural
   127 recursion over such type arguments.  Incomplete specification patterns
   128 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   129 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   130 Command 'print_theory' outputs the normalized system of recursive
   131 equations, see section "definitions".
   132 
   133 * Isar: improper proof element 'guess' is like 'obtain', but derives
   134 the obtained context from the course of reasoning!  For example:
   135 
   136   assume "EX x y. A x & B y"   -- "any previous fact"
   137   then guess x and y by clarify
   138 
   139 This technique is potentially adventurous, depending on the facts and
   140 proof tools being involved here.
   141 
   142 * Isar: known facts from the proof context may be specified as literal
   143 propositions, using ASCII back-quote syntax.  This works wherever
   144 named facts used to be allowed so far, in proof commands, proof
   145 methods, attributes etc.  Literal facts are retrieved from the context
   146 according to unification of type and term parameters.  For example,
   147 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   148 theorems in the current context, then these are valid literal facts:
   149 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   150 
   151 There is also a proof method "fact" which does the same composition
   152 for explicit goal states, e.g. the following proof texts coincide with
   153 certain special cases of literal facts:
   154 
   155   have "A" by fact                 ==  note `A`
   156   have "A ==> B" by fact           ==  note `A ==> B`
   157   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   158   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   159 
   160 * Isar: ":" (colon) is no longer a symbolic identifier character in
   161 outer syntax.  Thus symbolic identifiers may be used without
   162 additional white space in declarations like this: ``assume *: A''.
   163 
   164 * Isar: 'print_facts' prints all local facts of the current context,
   165 both named and unnamed ones.
   166 
   167 * Isar: 'def' now admits simultaneous definitions, e.g.:
   168 
   169   def x == "t" and y == "u"
   170 
   171 * Isar: added command 'unfolding', which is structurally similar to
   172 'using', but affects both the goal state and facts by unfolding given
   173 rewrite rules.  Thus many occurrences of the 'unfold' method or
   174 'unfolded' attribute may be replaced by first-class proof text.
   175 
   176 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   177 and command 'unfolding' now all support object-level equalities
   178 (potentially conditional).  The underlying notion of rewrite rule is
   179 analogous to the 'rule_format' attribute, but *not* that of the
   180 Simplifier (which is usually more generous).
   181 
   182 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   183 method expression within a sandbox consisting of the first N
   184 sub-goals, which need to exist.  For example, ``simp_all [3]''
   185 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   186 simplifies all new goals that emerge from applying rule foo to the
   187 originally first one.
   188 
   189 * Isar: schematic goals are no longer restricted to higher-order
   190 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   191 expected.
   192 
   193 * Isar: the conclusion of a long theorem statement is now either
   194 'shows' (a simultaneous conjunction, as before), or 'obtains'
   195 (essentially a disjunction of cases with local parameters and
   196 assumptions).  The latter allows to express general elimination rules
   197 adequately; in this notation common elimination rules look like this:
   198 
   199   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   200     assumes "EX x. P x"
   201     obtains x where "P x"
   202 
   203   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   204     assumes "A & B"
   205     obtains A and B
   206 
   207   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   208     assumes "A | B"
   209     obtains
   210       A
   211     | B
   212 
   213 The subsequent classical rules even refer to the formal "thesis"
   214 explicitly:
   215 
   216   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   217     obtains "~ thesis"
   218 
   219   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   220     obtains "thesis ==> something"
   221 
   222 The actual proof of an 'obtains' statement is analogous to that of the
   223 Isar proof element 'obtain', only that there may be several cases.
   224 Optional case names may be specified in parentheses; these will be
   225 available both in the present proof and as annotations in the
   226 resulting rule, for later use with the 'cases' method (cf. attribute
   227 case_names).
   228 
   229 * Isar: the assumptions of a long theorem statement are available as
   230 "assms" fact in the proof context.  This is more appropriate than the
   231 (historical) "prems", which refers to all assumptions of the current
   232 context, including those from the target locale, proof body etc.
   233 
   234 * Isar: 'print_statement' prints theorems from the current theory or
   235 proof context in long statement form, according to the syntax of a
   236 top-level lemma.
   237 
   238 * Isar: 'obtain' takes an optional case name for the local context
   239 introduction rule (default "that").
   240 
   241 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   242 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   243 to occur.
   244 
   245 * Pure: syntax "CONST name" produces a fully internalized constant
   246 according to the current context.  This is particularly useful for
   247 syntax translations that should refer to internal constant
   248 representations independently of name spaces.
   249 
   250 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   251 instead of "FOO ". This allows multiple binder declarations to coexist
   252 in the same context.  INCOMPATIBILITY.
   253 
   254 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   255 primitive that also works in a locale context (both for constants and
   256 fixed variables).  Type declaration and internal syntactic
   257 representation of given constants retrieved from the context.
   258 
   259 * Isar/locales: new derived specification elements 'axiomatization',
   260 'definition', 'abbreviation', which support type-inference, admit
   261 object-level specifications (equality, equivalence).  See also the
   262 isar-ref manual.  Examples:
   263 
   264   axiomatization
   265     eq  (infix "===" 50) where
   266     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   267 
   268   definition "f x y = x + y + 1"
   269   definition g where "g x = f x x"
   270 
   271   abbreviation
   272     neq  (infix "=!=" 50) where
   273     "x =!= y == ~ (x === y)"
   274 
   275 These specifications may be also used in a locale context.  Then the
   276 constants being introduced depend on certain fixed parameters, and the
   277 constant name is qualified by the locale base name.  An internal
   278 abbreviation takes care for convenient input and output, making the
   279 parameters implicit and using the original short name.  See also
   280 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   281 entities from a monomorphic theory.
   282 
   283 Presently, abbreviations are only available 'in' a target locale, but
   284 not inherited by general import expressions.  Also note that
   285 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   286 'translations' in common applications.
   287 
   288 Concrete syntax is attached to specified constants in internal form,
   289 independently of name spaces.  The parse tree representation is
   290 slightly different -- use 'notation' instead of raw 'syntax', and
   291 'translations' with explicit "CONST" markup to accommodate this.
   292 
   293 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   294 the current context.  Print mode "no_abbrevs" prevents inversion of
   295 abbreviations on output.
   296 
   297 * Isar/locales: improved parameter handling:
   298 - use of locales "var" and "struct" no longer necessary;
   299 - parameter renamings are no longer required to be injective.
   300   This enables, for example, to define a locale for endomorphisms thus:
   301   locale endom = homom mult mult h.
   302 
   303 * Isar/locales: changed the way locales with predicates are defined.
   304 Instead of accumulating the specification, the imported expression is
   305 now an interpretation.  INCOMPATIBILITY: different normal form of
   306 locale expressions.  In particular, in interpretations of locales with
   307 predicates, goals repesenting already interpreted fragments are not
   308 removed automatically.  Use methods `intro_locales' and
   309 `unfold_locales'; see below.
   310 
   311 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   312 provide backward reasoning on locales predicates.  The methods are
   313 aware of interpretations and discharge corresponding goals.
   314 `intro_locales' is less aggressive then `unfold_locales' and does not
   315 unfold predicates to assumptions.
   316 
   317 * Isar/locales: the order in which locale fragments are accumulated
   318 has changed.  This enables to override declarations from fragments due
   319 to interpretations -- for example, unwanted simp rules.
   320 
   321 * Provers/induct: improved internal context management to support
   322 local fixes and defines on-the-fly.  Thus explicit meta-level
   323 connectives !! and ==> are rarely required anymore in inductive goals
   324 (using object-logic connectives for this purpose has been long
   325 obsolete anyway).  The subsequent proof patterns illustrate advanced
   326 techniques of natural induction; general datatypes and inductive sets
   327 work analogously (see also src/HOL/Lambda for realistic examples).
   328 
   329 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   330 parameters:
   331 
   332   lemma
   333     fixes n :: nat and x :: 'a
   334     assumes a: "A n x"
   335     shows "P n x"
   336     using a                     -- {* make induct insert fact a *}
   337   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   338     case 0
   339     show ?case sorry
   340   next
   341     case (Suc n)
   342     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   343     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   344     show ?case sorry
   345   qed
   346 
   347 (2) This is how to perform induction over ``expressions of a certain
   348 form'', using a locally defined inductive parameter n == "a x"
   349 together with strengthening (the latter is usually required to get
   350 sufficiently flexible induction hypotheses):
   351 
   352   lemma
   353     fixes a :: "'a => nat"
   354     assumes a: "A (a x)"
   355     shows "P (a x)"
   356     using a
   357   proof (induct n == "a x" arbitrary: x)
   358     ...
   359 
   360 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   361 particular technique.
   362 
   363 (3) This is how to perform existential reasoning ('obtains' or
   364 'obtain') by induction, while avoiding explicit object-logic
   365 encodings:
   366 
   367   lemma
   368     fixes n :: nat
   369     obtains x :: 'a where "P n x" and "Q n x"
   370   proof (induct n arbitrary: thesis)
   371     case 0
   372     obtain x where "P 0 x" and "Q 0 x" sorry
   373     then show thesis by (rule 0)
   374   next
   375     case (Suc n)
   376     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   377     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   378     then show thesis by (rule Suc.prems)
   379   qed
   380 
   381 Here the 'arbitrary: thesis' specification essentially modifies the
   382 scope of the formal thesis parameter, in order to the get the whole
   383 existence statement through the induction as expected.
   384 
   385 * Provers/induct: mutual induction rules are now specified as a list
   386 of rule sharing the same induction cases.  HOL packages usually
   387 provide foo_bar.inducts for mutually defined items foo and bar
   388 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   389 specify mutual induction rules differently, i.e. like this:
   390 
   391   (induct rule: foo_bar.inducts)
   392   (induct set: foo bar)
   393   (induct type: foo bar)
   394 
   395 The ML function ProjectRule.projections turns old-style rules into the
   396 new format.
   397 
   398 * Provers/induct: improved handling of simultaneous goals.  Instead of
   399 introducing object-level conjunction, the statement is now split into
   400 several conclusions, while the corresponding symbolic cases are
   401 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   402 explicitly.  For example:
   403 
   404   lemma
   405     fixes n :: nat
   406     shows "P n" and "Q n"
   407   proof (induct n)
   408     case 0 case 1
   409     show "P 0" sorry
   410   next
   411     case 0 case 2
   412     show "Q 0" sorry
   413   next
   414     case (Suc n) case 1
   415     note `P n` and `Q n`
   416     show "P (Suc n)" sorry
   417   next
   418     case (Suc n) case 2
   419     note `P n` and `Q n`
   420     show "Q (Suc n)" sorry
   421   qed
   422 
   423 The split into subcases may be deferred as follows -- this is
   424 particularly relevant for goal statements with local premises.
   425 
   426   lemma
   427     fixes n :: nat
   428     shows "A n ==> P n" and "B n ==> Q n"
   429   proof (induct n)
   430     case 0
   431     {
   432       case 1
   433       note `A 0`
   434       show "P 0" sorry
   435     next
   436       case 2
   437       note `B 0`
   438       show "Q 0" sorry
   439     }
   440   next
   441     case (Suc n)
   442     note `A n ==> P n` and `B n ==> Q n`
   443     {
   444       case 1
   445       note `A (Suc n)`
   446       show "P (Suc n)" sorry
   447     next
   448       case 2
   449       note `B (Suc n)`
   450       show "Q (Suc n)" sorry
   451     }
   452   qed
   453 
   454 If simultaneous goals are to be used with mutual rules, the statement
   455 needs to be structured carefully as a two-level conjunction, using
   456 lists of propositions separated by 'and':
   457 
   458   lemma
   459     shows "a : A ==> P1 a"
   460           "a : A ==> P2 a"
   461       and "b : B ==> Q1 b"
   462           "b : B ==> Q2 b"
   463           "b : B ==> Q3 b"
   464   proof (induct set: A B)
   465 
   466 * Provers/induct: support coinduction as well.  See
   467 src/HOL/Library/Coinductive_List.thy for various examples.
   468 
   469 * Attribute "symmetric" produces result with standardized schematic
   470 variables (index 0).  Potential INCOMPATIBILITY.
   471 
   472 * Simplifier: by default the simplifier trace only shows top level
   473 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   474 default. Thus there is less danger of being flooded by the trace. The
   475 trace indicates where parts have been suppressed.
   476   
   477 * Provers/classical: removed obsolete classical version of elim_format
   478 attribute; classical elim/dest rules are now treated uniformly when
   479 manipulating the claset.
   480 
   481 * Provers/classical: stricter checks to ensure that supplied intro,
   482 dest and elim rules are well-formed; dest and elim rules must have at
   483 least one premise.
   484 
   485 * Provers/classical: attributes dest/elim/intro take an optional
   486 weight argument for the rule (just as the Pure versions).  Weights are
   487 ignored by automated tools, but determine the search order of single
   488 rule steps.
   489 
   490 * Syntax: input syntax now supports dummy variable binding "%_. b",
   491 where the body does not mention the bound variable.  Note that dummy
   492 patterns implicitly depend on their context of bounds, which makes
   493 "{_. _}" match any set comprehension as expected.  Potential
   494 INCOMPATIBILITY -- parse translations need to cope with syntactic
   495 constant "_idtdummy" in the binding position.
   496 
   497 * Syntax: removed obsolete syntactic constant "_K" and its associated
   498 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   499 for example "A -> B" => "Pi A (%_. B)".
   500 
   501 * Pure: 'class_deps' command visualizes the subclass relation, using
   502 the graph browser tool.
   503 
   504 * Pure: 'print_theory' now suppresses entities with internal name
   505 (trailing "_") by default; use '!' option for full details.
   506 
   507 
   508 *** HOL ***
   509 
   510 * Added syntactic class "size"; overloaded constant "size" now has
   511 type "'a::size ==> bool"
   512 
   513 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   514 dvd" to "Divides.div", "Divides.mod" and
   515 "Divides.dvd". INCOMPATIBILITY.
   516 
   517 * Added method "lexicographic_order" automatically synthesizes
   518 termination relations as lexicographic combinations of size measures
   519 -- 'function' package.
   520 
   521 * HOL/records: generalised field-update to take a function on the
   522 field rather than the new value: r(|A := x|) is translated to A_update
   523 (K x) r The K-combinator that is internally used is called K_record.
   524 INCOMPATIBILITY: Usage of the plain update functions has to be
   525 adapted.
   526  
   527 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   528 0 * x = 0, which are required for a semiring.  Richer structures do
   529 not inherit from semiring_0 anymore, because this property is a
   530 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   531 semiring_0, there is more to prove, but this is mostly trivial.
   532 
   533 * axclass "recpower" was generalized to arbitrary monoids, not just
   534 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   535 commutativity or a semiring property, add the corresponding classes.
   536 
   537 * Unified locale partial_order with class definition (cf. theory
   538 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   539 
   540 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   541 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   542 Isar level, use abbreviations instead.
   543 
   544 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   545 rarely occuring name references (e.g. ``List.op mem.simps'') require
   546 renaming (e.g. ``List.memberl.simps'').
   547 
   548 * Renamed constants "0" to "HOL.zero" and "1" to "HOL.one".
   549 INCOMPATIBILITY.
   550 
   551 * Added theory Code_Generator providing class 'eq', allowing for code
   552 generation with polymorphic equality.
   553 
   554 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   555 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   556 significant changes for setting up numeral syntax for types:
   557 
   558   - new constants Numeral.pred and Numeral.succ instead
   559       of former Numeral.bin_pred and Numeral.bin_succ.
   560   - Use integer operations instead of bin_add, bin_mult and so on.
   561   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   562   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   563 
   564 See HOL/Integ/IntArith.thy for an example setup.
   565 
   566 * New top level command 'normal_form' computes the normal form of a
   567 term that may contain free variables. For example ``normal_form
   568 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   569 suitable for heavy-duty computations because the functions are
   570 compiled to ML first.
   571 
   572 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   573 25 like -->); output depends on the "iff" print_mode, the default is
   574 "A = B" (with priority 50).
   575 
   576 * Renamed constants in HOL.thy and Orderings.thy:
   577     op +   ~> HOL.plus
   578     op -   ~> HOL.minus
   579     uminus ~> HOL.uminus
   580     op *   ~> HOL.times
   581     op <   ~> Orderings.less
   582     op <=  ~> Orderings.less_eq
   583 
   584 Adaptions may be required in the following cases:
   585 
   586 a) User-defined constants using any of the names "plus", "minus", "times",
   587 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   588 may go wrong.
   589 INCOMPATIBILITY: use more specific names.
   590 
   591 b) Variables named "plus", "minus", "times", "less", "less_eq"
   592 INCOMPATIBILITY: use more specific names.
   593 
   594 c) Permutative equations (e.g. "a + b = b + a")
   595 Since the change of names also changes the order of terms, permutative
   596 rewrite rules may get applied in a different order. Experience shows that
   597 this is rarely the case (only two adaptions in the whole Isabelle
   598 distribution).
   599 INCOMPATIBILITY: rewrite proofs
   600 
   601 d) ML code directly refering to constant names
   602 This in general only affects hand-written proof tactics, simprocs and so on.
   603 INCOMPATIBILITY: grep your sourcecode and replace names.
   604 
   605 * Relations less (<) and less_eq (<=) are also available on type bool.
   606 Modified syntax to disallow nesting without explicit parentheses,
   607 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   608 
   609 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   610 
   611 * Relation composition operator "op O" now has precedence 75 and binds
   612 stronger than union and intersection. INCOMPATIBILITY.
   613 
   614 * The old set interval syntax "{m..n(}" (and relatives) has been
   615 removed.  Use "{m..<n}" (and relatives) instead.
   616 
   617 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   618 "t = s" to False (by simproc "neq_simproc").  For backward
   619 compatibility this can be disabled by ML "reset use_neq_simproc".
   620 
   621 * "m dvd n" where m and n are numbers is evaluated to True/False by
   622 simp.
   623 
   624 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   625 
   626 * Theorem setsum_mult renamed to setsum_right_distrib.
   627 
   628 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   629 ``rule'' method.
   630 
   631 * Reimplemented methods ``sat'' and ``satx'', with several
   632 improvements: goals no longer need to be stated as "<prems> ==>
   633 False", equivalences (i.e. "=" on type bool) are handled, variable
   634 names of the form "lit_<n>" are no longer reserved, significant
   635 speedup.
   636 
   637 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   638 zChaff is still supported as well.
   639 
   640 * 'inductive' and 'datatype': provide projections of mutual rules,
   641 bundled as foo_bar.inducts;
   642 
   643 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   644 Library.
   645 
   646 * Library: moved theory Accessible_Part to main HOL.
   647 
   648 * Library: added theory Coinductive_List of potentially infinite lists
   649 as greatest fixed-point.
   650 
   651 * Library: added theory AssocList which implements (finite) maps as
   652 association lists.
   653 
   654 * Added proof method ``evaluation'' for efficiently solving a goal
   655 (i.e. a boolean expression) by compiling it to ML. The goal is
   656 "proved" (via an oracle) if it evaluates to True.
   657 
   658 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   659 also when invoked by the simplifier.  This results in the simplifier
   660 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   661 fast_arith_split_limit to 0 to obtain the old behavior.
   662 
   663 * Support for hex (0x20) and binary (0b1001) numerals.
   664 
   665 * New method: reify eqs (t), where eqs are equations for an
   666 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   667 parameter, computes a term s::'b and a list xs::'a list and proves the
   668 theorem I xs s = t. This is also known as reification or quoting. The
   669 resulting theorem is applied to the subgoal to substitute t with I xs
   670 s.  If t is omitted, the subgoal itself is reified.
   671 
   672 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   673 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   674 where f is supposed to be a computable function (in the sense of code
   675 generattion). The method uses reify to compute s and xs as above then
   676 applies corr_thm and uses normalization by evaluation to "prove" f s =
   677 r and finally gets the theorem t = r, which is again applied to the
   678 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   679 
   680 * Reflection: Automatic refification now handels binding, an example
   681 is available in HOL/ex/ReflectionEx.thy
   682 
   683 
   684 *** HOL-Algebra ***
   685 
   686 * Formalisation of ideals and the quotient construction over rings.
   687 
   688 * Order and lattice theory no longer based on records.
   689 INCOMPATIBILITY.
   690 
   691 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   692 greatest_closed.  INCOMPATIBILITY.
   693 
   694 * Method algebra is now set up via an attribute.  For examples see
   695 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   696 of algebraic structures.
   697 
   698 * Renamed theory CRing to Ring.
   699 
   700 
   701 *** HOL-Complex ***
   702 
   703 * Theory Real: new method ferrack implements quantifier elimination
   704 for linear arithmetic over the reals. The quantifier elimination
   705 feature is used only for decision, for compatibility with arith. This
   706 means a goal is either solved or left unchanged, no simplification.
   707 
   708 * Real: New axiomatic classes formalize real normed vector spaces and
   709 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   710 and norm :: 'a => real.
   711 
   712 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   713 from reals into other types. The overloaded constant Reals :: 'a set
   714 is now defined as range of_real; potential INCOMPATIBILITY.
   715 
   716 * Hyperreal: Several constants that previously worked only for the
   717 reals have been generalized, so they now work over arbitrary vector
   718 spaces. Type annotations may need to be added in some cases; potential
   719 INCOMPATIBILITY.
   720 
   721   Infinitesimal  :: ('a::real_normed_vector) star set"
   722   HFinite        :: ('a::real_normed_vector) star set"
   723   HInfinite      :: ('a::real_normed_vector) star set"
   724   approx         :: ('a::real_normed_vector) star => 'a star => bool
   725   monad          :: ('a::real_normed_vector) star => 'a star set
   726   galaxy         :: ('a::real_normed_vector) star => 'a star set
   727   (NS)LIMSEQ     :: [nat, 'a::real_normed_vector, 'a] => bool
   728   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   729   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   730   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   731   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   732   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   733   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   734 
   735 * Complex: Some complex-specific constants are now abbreviations for
   736 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   737 hnorm.  Other constants have been entirely removed in favor of the
   738 polymorphic versions (INCOMPATIBILITY):
   739 
   740   approx        <-- capprox
   741   HFinite       <-- CFinite
   742   HInfinite     <-- CInfinite
   743   Infinitesimal <-- CInfinitesimal
   744   monad         <-- cmonad
   745   galaxy        <-- cgalaxy
   746   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   747   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   748   (ns)deriv     <-- (ns)cderiv
   749 
   750 
   751 *** ML ***
   752 
   753 * Pure/library:
   754 
   755   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   756   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   757 
   758 The semantics of "burrow" is: "take a function with *simulatanously*
   759 transforms a list of value, and apply it *simulatanously* to a list of
   760 list of values of the appropriate type". Compare this with "map" which
   761 would *not* apply its argument function simulatanously but in
   762 sequence; "fold_burrow" has an additional context.
   763 
   764 * Pure/library: functions map2 and fold2 with curried syntax for
   765 simultanous mapping and folding:
   766 
   767     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   768     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   769 
   770 * Pure/library: indexed lists - some functions in the Isabelle library
   771 treating lists over 'a as finite mappings from [0...n] to 'a have been
   772 given more convenient names and signatures reminiscent of similar
   773 functions for alists, tables, etc:
   774 
   775   val nth: 'a list -> int -> 'a 
   776   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   777   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   778 
   779 Note that fold_index starts counting at index 0, not 1 like foldln
   780 used to.
   781 
   782 * Pure/library: added general ``divide_and_conquer'' combinator on
   783 lists.
   784 
   785 * Pure/General/table.ML: the join operations now works via exceptions
   786 DUP/SAME instead of type option.  This is simpler in simple cases, and
   787 admits slightly more efficient complex applications.
   788 
   789 * Pure: datatype Context.generic joins theory/Proof.context and
   790 provides some facilities for code that works in either kind of
   791 context, notably GenericDataFun for uniform theory and proof data.
   792 
   793 * Pure: 'advanced' translation functions (parse_translation etc.) now
   794 use Context.generic instead of just theory.
   795 
   796 * Pure: simplified internal attribute type, which is now always
   797 Context.generic * thm -> Context.generic * thm.  Global (theory)
   798 vs. local (Proof.context) attributes have been discontinued, while
   799 minimizing code duplication.  Thm.rule_attribute and
   800 Thm.declaration_attribute build canonical attributes; see also
   801 structure Context for further operations on Context.generic, notably
   802 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   803 declarations and definitions.
   804 
   805 * Pure/kernel: consts certification ignores sort constraints given in
   806 signature declarations.  (This information is not relevant to the
   807 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   808 potential INCOMPATIBILITY.
   809 
   810 * Pure: axiomatic type classes are now purely definitional, with
   811 explicit proofs of class axioms and super class relations performed
   812 internally.  See Pure/axclass.ML for the main internal interfaces --
   813 notably AxClass.define_class supercedes AxClass.add_axclass, and
   814 AxClass.axiomatize_class/classrel/arity supercede
   815 Sign.add_classes/classrel/arities.
   816 
   817 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   818 global/local versions on theory vs. Proof.context have been
   819 discontinued; Attrib.syntax and Method.syntax have been adapted
   820 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   821 attributes, methods, etc.
   822 
   823 * Pure: several functions of signature "... -> theory -> theory * ..."
   824 have been reoriented to "... -> theory -> ... * theory" in order to
   825 allow natural usage in combination with the ||>, ||>>, |-> and
   826 fold_map combinators.
   827 
   828 * Pure: official theorem names (closed derivations) and additional
   829 comments (tags) are now strictly separate.  Name hints -- which are
   830 maintained as tags -- may be attached any time without affecting the
   831 derivation.
   832 
   833 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   834 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   835 achieve the old behaviour.
   836 
   837 * Pure: the "Goal" constant is now called "prop", supporting a
   838 slightly more general idea of ``protecting'' meta-level rule
   839 statements.
   840 
   841 * Pure: Logic.(un)varify only works in a global context, which is now
   842 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   843 Logic.legacy_(un)varify as temporary workaround.
   844 
   845 * Pure: structure Name provides scalable operations for generating
   846 internal variable names, notably Name.variants etc.  This replaces
   847 some popular functions from term.ML:
   848 
   849   Term.variant		->  Name.variant
   850   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   851   Term.invent_names	->  Name.invent_list
   852 
   853 Note that low-level renaming rarely occurs in new code -- operations
   854 from structure Variable are used instead (see below).
   855 
   856 * Pure: structure Variable provides fundamental operations for proper
   857 treatment of fixed/schematic variables in a context.  For example,
   858 Variable.import introduces fixes for schematics of given facts and
   859 Variable.export reverses the effect (up to renaming) -- this replaces
   860 various freeze_thaw operations.
   861 
   862 * Pure: structure Goal provides simple interfaces for
   863 init/conclude/finish and tactical prove operations (replacing former
   864 Tactic.prove).  Goal.prove is the canonical way to prove results
   865 within a given context; Goal.prove_global is a degraded version for
   866 theory level goals, including a global Drule.standard.  Note that
   867 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   868 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   869 in a locale context).
   870 
   871 * Isar: simplified treatment of user-level errors, using exception
   872 ERROR of string uniformly.  Function error now merely raises ERROR,
   873 without any side effect on output channels.  The Isar toplevel takes
   874 care of proper display of ERROR exceptions.  ML code may use plain
   875 handle/can/try; cat_error may be used to concatenate errors like this:
   876 
   877   ... handle ERROR msg => cat_error msg "..."
   878 
   879 Toplevel ML code (run directly or through the Isar toplevel) may be
   880 embedded into the Isar toplevel with exception display/debug like
   881 this:
   882 
   883   Isar.toplevel (fn () => ...)
   884 
   885 INCOMPATIBILITY, removed special transform_error facilities, removed
   886 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   887 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   888 -- use plain ERROR instead.
   889 
   890 * Isar: theory setup now has type (theory -> theory), instead of a
   891 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   892 
   893 * Isar: installed ML toplevel pretty printer for type Proof.context,
   894 subject to ProofContext.debug/verbose flags.
   895 
   896 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   897 theory before entering a proof state.  Transactions now always see a
   898 quasi-functional intermediate checkpoint, both in interactive and
   899 batch mode.
   900 
   901 * Simplifier: the simpset of a running simplification process now
   902 contains a proof context (cf. Simplifier.the_context), which is the
   903 very context that the initial simpset has been retrieved from (by
   904 simpset_of/local_simpset_of).  Consequently, all plug-in components
   905 (solver, looper etc.) may depend on arbitrary proof data.
   906 
   907 * Simplifier.inherit_context inherits the proof context (plus the
   908 local bounds) of the current simplification process; any simproc
   909 etc. that calls the Simplifier recursively should do this!  Removed
   910 former Simplifier.inherit_bounds, which is already included here --
   911 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   912 specify an explicit context using Simplifier.context/theory_context.
   913 
   914 * Simplifier/Classical Reasoner: more abstract interfaces
   915 change_simpset/claset for modifying the simpset/claset reference of a
   916 theory; raw versions simpset/claset_ref etc. have been discontinued --
   917 INCOMPATIBILITY.
   918 
   919 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   920 "Trueprop" etc.
   921 
   922 
   923 *** System ***
   924 
   925 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   926 locations -- now includes the Isabelle version identifier as well.
   927 This simplifies use of multiple Isabelle installations.
   928 
   929 * isabelle-process: option -S (secure mode) disables some critical
   930 operations, notably runtime compilation and evaluation of ML source
   931 code.
   932 
   933 
   934 New in Isabelle2005 (October 2005)
   935 ----------------------------------
   936 
   937 *** General ***
   938 
   939 * Theory headers: the new header syntax for Isar theories is
   940 
   941   theory <name>
   942   imports <theory1> ... <theoryN>
   943   uses <file1> ... <fileM>
   944   begin
   945 
   946 where the 'uses' part is optional.  The previous syntax
   947 
   948   theory <name> = <theory1> + ... + <theoryN>:
   949 
   950 will disappear in the next release.  Use isatool fixheaders to convert
   951 existing theory files.  Note that there is no change in ancient
   952 non-Isar theories now, but these will disappear soon.
   953 
   954 * Theory loader: parent theories can now also be referred to via
   955 relative and absolute paths.
   956 
   957 * Command 'find_theorems' searches for a list of criteria instead of a
   958 list of constants. Known criteria are: intro, elim, dest, name:string,
   959 simp:term, and any term. Criteria can be preceded by '-' to select
   960 theorems that do not match. Intro, elim, dest select theorems that
   961 match the current goal, name:s selects theorems whose fully qualified
   962 name contain s, and simp:term selects all simplification rules whose
   963 lhs match term.  Any other term is interpreted as pattern and selects
   964 all theorems matching the pattern. Available in ProofGeneral under
   965 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   966 
   967   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   968 
   969 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   970 matching the current goal as introduction rule and not having "HOL."
   971 in their name (i.e. not being defined in theory HOL).
   972 
   973 * Command 'thms_containing' has been discontinued in favour of
   974 'find_theorems'; INCOMPATIBILITY.
   975 
   976 * Communication with Proof General is now 8bit clean, which means that
   977 Unicode text in UTF-8 encoding may be used within theory texts (both
   978 formal and informal parts).  Cf. option -U of the Isabelle Proof
   979 General interface.  Here are some simple examples (cf. src/HOL/ex):
   980 
   981   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   982   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   983 
   984 * Improved efficiency of the Simplifier and, to a lesser degree, the
   985 Classical Reasoner.  Typical big applications run around 2 times
   986 faster.
   987 
   988 
   989 *** Document preparation ***
   990 
   991 * Commands 'display_drafts' and 'print_drafts' perform simple output
   992 of raw sources.  Only those symbols that do not require additional
   993 LaTeX packages (depending on comments in isabellesym.sty) are
   994 displayed properly, everything else is left verbatim.  isatool display
   995 and isatool print are used as front ends (these are subject to the
   996 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   997 
   998 * Command tags control specific markup of certain regions of text,
   999 notably folding and hiding.  Predefined tags include "theory" (for
  1000 theory begin and end), "proof" for proof commands, and "ML" for
  1001 commands involving ML code; the additional tags "visible" and
  1002 "invisible" are unused by default.  Users may give explicit tag
  1003 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1004 interpretation of tags is determined by the LaTeX job during document
  1005 preparation: see option -V of isatool usedir, or options -n and -t of
  1006 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1007 \isadroptag.
  1008 
  1009 Several document versions may be produced at the same time via isatool
  1010 usedir (the generated index.html will link all of them).  Typical
  1011 specifications include ''-V document=theory,proof,ML'' to present
  1012 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1013 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1014 these parts without any formal replacement text.  The Isabelle site
  1015 default settings produce ''document'' and ''outline'' versions as
  1016 specified above.
  1017 
  1018 * Several new antiquotations:
  1019 
  1020   @{term_type term} prints a term with its type annotated;
  1021 
  1022   @{typeof term} prints the type of a term;
  1023 
  1024   @{const const} is the same as @{term const}, but checks that the
  1025   argument is a known logical constant;
  1026 
  1027   @{term_style style term} and @{thm_style style thm} print a term or
  1028   theorem applying a "style" to it
  1029 
  1030   @{ML text}
  1031 
  1032 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1033 definitions, equations, inequations etc., 'concl' printing only the
  1034 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1035 to print the specified premise.  TermStyle.add_style provides an ML
  1036 interface for introducing further styles.  See also the "LaTeX Sugar"
  1037 document practical applications.  The ML antiquotation prints
  1038 type-checked ML expressions verbatim.
  1039 
  1040 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1041 and 'text' support optional locale specification '(in loc)', which
  1042 specifies the default context for interpreting antiquotations.  For
  1043 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1044 
  1045 * Option 'locale=NAME' of antiquotations specifies an alternative
  1046 context interpreting the subsequent argument.  For example: @{thm
  1047 [locale=lattice] inf_assoc}.
  1048 
  1049 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1050 a proof context.
  1051 
  1052 * Proper output of antiquotations for theory commands involving a
  1053 proof context (such as 'locale' or 'theorem (in loc) ...').
  1054 
  1055 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1056 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1057 
  1058 * isatool usedir: new option -C (default true) controls whether option
  1059 -D should include a copy of the original document directory; -C false
  1060 prevents unwanted effects such as copying of administrative CVS data.
  1061 
  1062 
  1063 *** Pure ***
  1064 
  1065 * Considerably improved version of 'constdefs' command.  Now performs
  1066 automatic type-inference of declared constants; additional support for
  1067 local structure declarations (cf. locales and HOL records), see also
  1068 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1069 sequential dependencies of definitions within a single 'constdefs'
  1070 section; moreover, the declared name needs to be an identifier.  If
  1071 all fails, consider to fall back on 'consts' and 'defs' separately.
  1072 
  1073 * Improved indexed syntax and implicit structures.  First of all,
  1074 indexed syntax provides a notational device for subscripted
  1075 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1076 expressions.  Secondly, in a local context with structure
  1077 declarations, number indexes \<^sub>n or the empty index (default
  1078 number 1) refer to a certain fixed variable implicitly; option
  1079 show_structs controls printing of implicit structures.  Typical
  1080 applications of these concepts involve record types and locales.
  1081 
  1082 * New command 'no_syntax' removes grammar declarations (and
  1083 translations) resulting from the given syntax specification, which is
  1084 interpreted in the same manner as for the 'syntax' command.
  1085 
  1086 * 'Advanced' translation functions (parse_translation etc.) may depend
  1087 on the signature of the theory context being presently used for
  1088 parsing/printing, see also isar-ref manual.
  1089 
  1090 * Improved 'oracle' command provides a type-safe interface to turn an
  1091 ML expression of type theory -> T -> term into a primitive rule of
  1092 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1093 is already included here); see also FOL/ex/IffExample.thy;
  1094 INCOMPATIBILITY.
  1095 
  1096 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1097 before); "cI" is no longer bound, use "c.intro" instead.
  1098 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1099 axclasses vs. locales.
  1100 
  1101 * Improved internal renaming of symbolic identifiers -- attach primes
  1102 instead of base 26 numbers.
  1103 
  1104 * New flag show_question_marks controls printing of leading question
  1105 marks in schematic variable names.
  1106 
  1107 * In schematic variable names, *any* symbol following \<^isub> or
  1108 \<^isup> is now treated as part of the base name.  For example, the
  1109 following works without printing of awkward ".0" indexes:
  1110 
  1111   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1112     by simp
  1113 
  1114 * Inner syntax includes (*(*nested*) comments*).
  1115 
  1116 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1117 annotations as "(00...)".
  1118 
  1119 * Clear separation of logical types and nonterminals, where the latter
  1120 may only occur in 'syntax' specifications or type abbreviations.
  1121 Before that distinction was only partially implemented via type class
  1122 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1123 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1124 exotic syntax specifications may require further adaption
  1125 (e.g. Cube/Cube.thy).
  1126 
  1127 * Removed obsolete type class "logic", use the top sort {} instead.
  1128 Note that non-logical types should be declared as 'nonterminals'
  1129 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1130 specifications.
  1131 
  1132 * Attributes 'induct' and 'cases': type or set names may now be
  1133 locally fixed variables as well.
  1134 
  1135 * Simplifier: can now control the depth to which conditional rewriting
  1136 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1137 Limit.
  1138 
  1139 * Simplifier: simplification procedures may now take the current
  1140 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1141 interface), which is very useful for calling the Simplifier
  1142 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1143 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1144 low-level mk_simproc no longer applies Logic.varify internally, to
  1145 allow for use in a context of fixed variables.
  1146 
  1147 * thin_tac now works even if the assumption being deleted contains !!
  1148 or ==>.  More generally, erule now works even if the major premise of
  1149 the elimination rule contains !! or ==>.
  1150 
  1151 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1152 
  1153 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1154 from Pure, which contains all common declarations already.  Both
  1155 theories are defined via plain Isabelle/Isar .thy files.
  1156 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1157 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1158 use isatool fixcpure to adapt your theory and ML sources.
  1159 
  1160 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1161 selections of theorems in named facts via index ranges.
  1162 
  1163 * 'print_theorems': in theory mode, really print the difference
  1164 wrt. the last state (works for interactive theory development only),
  1165 in proof mode print all local facts (cf. 'print_facts');
  1166 
  1167 * 'hide': option '(open)' hides only base names.
  1168 
  1169 * More efficient treatment of intermediate checkpoints in interactive
  1170 theory development.
  1171 
  1172 * Code generator is now invoked via code_module (incremental code
  1173 generation) and code_library (modular code generation, ML structures
  1174 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1175 must be quoted when used as identifiers.
  1176 
  1177 * New 'value' command for reading, evaluating and printing terms using
  1178 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1179 quoted when used as identifier.
  1180 
  1181 
  1182 *** Locales ***
  1183 
  1184 * New commands for the interpretation of locale expressions in
  1185 theories (1), locales (2) and proof contexts (3).  These generate
  1186 proof obligations from the expression specification.  After the
  1187 obligations have been discharged, theorems of the expression are added
  1188 to the theory, target locale or proof context.  The synopsis of the
  1189 commands is a follows:
  1190 
  1191   (1) interpretation expr inst
  1192   (2) interpretation target < expr
  1193   (3) interpret expr inst
  1194 
  1195 Interpretation in theories and proof contexts require a parameter
  1196 instantiation of terms from the current context.  This is applied to
  1197 specifications and theorems of the interpreted expression.
  1198 Interpretation in locales only permits parameter renaming through the
  1199 locale expression.  Interpretation is smart in that interpretations
  1200 that are active already do not occur in proof obligations, neither are
  1201 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1202 inspect active interpretations of a particular locale.  For details,
  1203 see the Isar Reference manual.  Examples can be found in
  1204 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1205 
  1206 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1207 'interpret' instead.
  1208 
  1209 * New context element 'constrains' for adding type constraints to
  1210 parameters.
  1211 
  1212 * Context expressions: renaming of parameters with syntax
  1213 redeclaration.
  1214 
  1215 * Locale declaration: 'includes' disallowed.
  1216 
  1217 * Proper static binding of attribute syntax -- i.e. types / terms /
  1218 facts mentioned as arguments are always those of the locale definition
  1219 context, independently of the context of later invocations.  Moreover,
  1220 locale operations (renaming and type / term instantiation) are applied
  1221 to attribute arguments as expected.
  1222 
  1223 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1224 actual attributes; rare situations may require Attrib.attribute to
  1225 embed those attributes into Attrib.src that lack concrete syntax.
  1226 Attribute implementations need to cooperate properly with the static
  1227 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1228 Attrib.XXX_thm etc. already do the right thing without further
  1229 intervention.  Only unusual applications -- such as "where" or "of"
  1230 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1231 on the context and the facts involved -- may have to assign parsed
  1232 values to argument tokens explicitly.
  1233 
  1234 * Changed parameter management in theorem generation for long goal
  1235 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1236 theorem statement in rare situations.
  1237 
  1238 * Locale inspection command 'print_locale' omits notes elements.  Use
  1239 'print_locale!' to have them included in the output.
  1240 
  1241 
  1242 *** Provers ***
  1243 
  1244 * Provers/hypsubst.ML: improved version of the subst method, for
  1245 single-step rewriting: it now works in bound variable contexts. New is
  1246 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1247 rewrite a different subterm than the original subst method, which is
  1248 still available as 'simplesubst'.
  1249 
  1250 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1251 and quasi orders.
  1252 
  1253 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1254 reflexive-transitive closure of relations.
  1255 
  1256 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1257 limit (previously hard-coded with a value of 20) user-definable.
  1258 
  1259 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1260 is peformed already.  Object-logics merely need to finish their
  1261 initial simpset configuration as before.  INCOMPATIBILITY.
  1262 
  1263 
  1264 *** HOL ***
  1265 
  1266 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1267 
  1268   syntax (epsilon)
  1269     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1270 
  1271 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1272 and x-symbol; use option '-m epsilon' to get it actually printed.
  1273 Moreover, the mathematically important symbolic identifier \<epsilon>
  1274 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1275 
  1276 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1277 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1278 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1279 support corresponding Isar calculations.
  1280 
  1281 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1282 instead of ":".
  1283 
  1284 * theory SetInterval: changed the syntax for open intervals:
  1285 
  1286   Old       New
  1287   {..n(}    {..<n}
  1288   {)n..}    {n<..}
  1289   {m..n(}   {m..<n}
  1290   {)m..n}   {m<..n}
  1291   {)m..n(}  {m<..<n}
  1292 
  1293 The old syntax is still supported but will disappear in the next
  1294 release.  For conversion use the following Emacs search and replace
  1295 patterns (these are not perfect but work quite well):
  1296 
  1297   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1298   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1299 
  1300 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1301 equalities in commutative rings; method 'algebra' provides a generic
  1302 interface.
  1303 
  1304 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1305 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1306 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1307 be a tuple pattern.
  1308 
  1309 Some new syntax forms are available:
  1310 
  1311   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1312   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1313   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1314   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1315 
  1316 The latter form "\<Sum>x < k. e" used to be based on a separate
  1317 function "Summation", which has been discontinued.
  1318 
  1319 * theory Finite_Set: in structured induction proofs, the insert case
  1320 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1321 (insert F x)'.
  1322 
  1323 * The 'refute' command has been extended to support a much larger
  1324 fragment of HOL, including axiomatic type classes, constdefs and
  1325 typedefs, inductive datatypes and recursion.
  1326 
  1327 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1328 Requires zChaff with proof generation to be installed.  See
  1329 HOL/ex/SAT_Examples.thy for examples.
  1330 
  1331 * Datatype induction via method 'induct' now preserves the name of the
  1332 induction variable. For example, when proving P(xs::'a list) by
  1333 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1334 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1335 in unstructured proof scripts.
  1336 
  1337 * Reworked implementation of records.  Improved scalability for
  1338 records with many fields, avoiding performance problems for type
  1339 inference. Records are no longer composed of nested field types, but
  1340 of nested extension types. Therefore the record type only grows linear
  1341 in the number of extensions and not in the number of fields.  The
  1342 top-level (users) view on records is preserved.  Potential
  1343 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1344 old record representation. The type generated for a record is called
  1345 <record_name>_ext_type.
  1346 
  1347 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1348 proofs triggered by a record definition or a simproc (if
  1349 quick_and_dirty is enabled).  Definitions of large records can take
  1350 quite long.
  1351 
  1352 New simproc record_upd_simproc for simplification of multiple record
  1353 updates enabled by default.  Moreover, trivial updates are also
  1354 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1355 occasionally, since simplification is more powerful by default.
  1356 
  1357 * typedef: proper support for polymorphic sets, which contain extra
  1358 type-variables in the term.
  1359 
  1360 * Simplifier: automatically reasons about transitivity chains
  1361 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1362 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1363 old proofs break occasionally as simplification may now solve more
  1364 goals than previously.
  1365 
  1366 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1367 present.  Works for all partial orders (class "order"), in particular
  1368 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1369 just like y <= x.
  1370 
  1371 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1372 bound variable or a constant then the let is unfolded.  Otherwise
  1373 first a is simplified to b, and then f b is simplified to g. If
  1374 possible we abstract b from g arriving at "let x = b in h x",
  1375 otherwise we unfold the let and arrive at g.  The simproc can be
  1376 enabled/disabled by the reference use_let_simproc.  Potential
  1377 INCOMPATIBILITY since simplification is more powerful by default.
  1378 
  1379 * Classical reasoning: the meson method now accepts theorems as arguments.
  1380 
  1381 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1382 jobs to provide advice on the provability of subgoals.
  1383 
  1384 * Theory OrderedGroup and Ring_and_Field: various additions and
  1385 improvements to faciliate calculations involving equalities and
  1386 inequalities.
  1387 
  1388 The following theorems have been eliminated or modified
  1389 (INCOMPATIBILITY):
  1390 
  1391   abs_eq             now named abs_of_nonneg
  1392   abs_of_ge_0        now named abs_of_nonneg
  1393   abs_minus_eq       now named abs_of_nonpos
  1394   imp_abs_id         now named abs_of_nonneg
  1395   imp_abs_neg_id     now named abs_of_nonpos
  1396   mult_pos           now named mult_pos_pos
  1397   mult_pos_le        now named mult_nonneg_nonneg
  1398   mult_pos_neg_le    now named mult_nonneg_nonpos
  1399   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1400   mult_neg           now named mult_neg_neg
  1401   mult_neg_le        now named mult_nonpos_nonpos
  1402 
  1403 * Theory Parity: added rules for simplifying exponents.
  1404 
  1405 * Theory List:
  1406 
  1407 The following theorems have been eliminated or modified
  1408 (INCOMPATIBILITY):
  1409 
  1410   list_all_Nil       now named list_all.simps(1)
  1411   list_all_Cons      now named list_all.simps(2)
  1412   list_all_conv      now named list_all_iff
  1413   set_mem_eq         now named mem_iff
  1414 
  1415 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1416 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1417 
  1418 
  1419 *** HOL-Complex ***
  1420 
  1421 * Theory RealDef: better support for embedding natural numbers and
  1422 integers in the reals.
  1423 
  1424 The following theorems have been eliminated or modified
  1425 (INCOMPATIBILITY):
  1426 
  1427   exp_ge_add_one_self  now requires no hypotheses
  1428   real_of_int_add      reversed direction of equality (use [symmetric])
  1429   real_of_int_minus    reversed direction of equality (use [symmetric])
  1430   real_of_int_diff     reversed direction of equality (use [symmetric])
  1431   real_of_int_mult     reversed direction of equality (use [symmetric])
  1432 
  1433 * Theory RComplete: expanded support for floor and ceiling functions.
  1434 
  1435 * Theory Ln is new, with properties of the natural logarithm
  1436 
  1437 * Hyperreal: There is a new type constructor "star" for making
  1438 nonstandard types.  The old type names are now type synonyms:
  1439 
  1440   hypreal = real star
  1441   hypnat = nat star
  1442   hcomplex = complex star
  1443 
  1444 * Hyperreal: Many groups of similarly-defined constants have been
  1445 replaced by polymorphic versions (INCOMPATIBILITY):
  1446 
  1447   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1448 
  1449   starset      <-- starsetNat, starsetC
  1450   *s*          <-- *sNat*, *sc*
  1451   starset_n    <-- starsetNat_n, starsetC_n
  1452   *sn*         <-- *sNatn*, *scn*
  1453   InternalSets <-- InternalNatSets, InternalCSets
  1454 
  1455   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1456   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1457   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1458   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1459   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1460 
  1461 * Hyperreal: Many type-specific theorems have been removed in favor of
  1462 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1463 
  1464   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1465   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1466   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1467   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1468   right_minus <-- hypreal_add_minus
  1469   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1470   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1471   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1472   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1473   mult_1_right <-- hcomplex_mult_one_right
  1474   mult_zero_left <-- hcomplex_mult_zero_left
  1475   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1476   right_distrib <-- hypnat_add_mult_distrib2
  1477   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1478   right_inverse <-- hypreal_mult_inverse
  1479   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1480   order_refl <-- {hypreal,hypnat}_le_refl
  1481   order_trans <-- {hypreal,hypnat}_le_trans
  1482   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1483   order_less_le <-- {hypreal,hypnat}_less_le
  1484   linorder_linear <-- {hypreal,hypnat}_le_linear
  1485   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1486   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1487   add_nonneg_nonneg <-- hypreal_le_add_order
  1488 
  1489 * Hyperreal: Separate theorems having to do with type-specific
  1490 versions of constants have been merged into theorems that apply to the
  1491 new polymorphic constants (INCOMPATIBILITY):
  1492 
  1493   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1494   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1495   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1496   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1497   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1498   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1499   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1500   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1501   STAR_diff <-- {STAR,STARC}_diff
  1502   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1503     STARC_hcomplex_of_complex}_image_subset
  1504   starset_n_Un <-- starset{Nat,C}_n_Un
  1505   starset_n_Int <-- starset{Nat,C}_n_Int
  1506   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1507   starset_n_diff <-- starset{Nat,C}_n_diff
  1508   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1509   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1510   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1511   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1512   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1513   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1514   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1515   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1516   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1517   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1518   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1519   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1520   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1521   starfun_diff <-- starfun{C,RC,CR}_diff
  1522   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1523   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1524   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1525   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1526   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1527   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1528   starfun_Id <-- starfunC_Id
  1529   starfun_approx <-- starfun{Nat,CR}_approx
  1530   starfun_capprox <-- starfun{C,RC}_capprox
  1531   starfun_abs <-- starfunNat_rabs
  1532   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1533   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1534   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1535   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1536   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1537   starfun_add_approx <-- starfunCR_add_approx
  1538   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1539   starfun_divide <-- starfun{C,CR,RC}_divide
  1540   starfun_n <-- starfun{Nat,C}_n
  1541   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1542   starfun_n_add <-- starfun{Nat,C}_n_add
  1543   starfun_n_add_minus <-- starfunNat_n_add_minus
  1544   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1545   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1546   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1547 
  1548   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1549   star_n_minus <-- {hypreal,hcomplex}_minus
  1550   star_n_diff <-- {hypreal,hcomplex}_diff
  1551   star_n_mult <-- {hypreal,hcomplex}_mult
  1552   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1553   star_n_le <-- {hypreal,hypnat}_le
  1554   star_n_less <-- {hypreal,hypnat}_less
  1555   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1556   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1557   star_n_abs <-- hypreal_hrabs
  1558   star_n_divide <-- hcomplex_divide
  1559 
  1560   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1561   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1562   star_of_diff <-- hypreal_of_real_diff
  1563   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1564   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1565   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1566   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1567   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1568   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1569   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1570   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1571   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1572   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1573   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1574   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1575   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1576   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1577   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1578   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1579   star_of_power <-- hypreal_of_real_power
  1580   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1581 
  1582 * Hyperreal: new method "transfer" that implements the transfer
  1583 principle of nonstandard analysis. With a subgoal that mentions
  1584 nonstandard types like "'a star", the command "apply transfer"
  1585 replaces it with an equivalent one that mentions only standard types.
  1586 To be successful, all free variables must have standard types; non-
  1587 standard variables must have explicit universal quantifiers.
  1588 
  1589 * Hyperreal: A theory of Taylor series.
  1590 
  1591 
  1592 *** HOLCF ***
  1593 
  1594 * Discontinued special version of 'constdefs' (which used to support
  1595 continuous functions) in favor of the general Pure one with full
  1596 type-inference.
  1597 
  1598 * New simplification procedure for solving continuity conditions; it
  1599 is much faster on terms with many nested lambda abstractions (cubic
  1600 instead of exponential time).
  1601 
  1602 * New syntax for domain package: selector names are now optional.
  1603 Parentheses should be omitted unless argument is lazy, for example:
  1604 
  1605   domain 'a stream = cons "'a" (lazy "'a stream")
  1606 
  1607 * New command 'fixrec' for defining recursive functions with pattern
  1608 matching; defining multiple functions with mutual recursion is also
  1609 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1610 sinr, or any data constructor defined by the domain package. The given
  1611 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1612 syntax and examples.
  1613 
  1614 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1615 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1616 but the proof obligation additionally includes an admissibility
  1617 requirement. The packages generate instances of class cpo or pcpo,
  1618 with continuity and strictness theorems for Rep and Abs.
  1619 
  1620 * HOLCF: Many theorems have been renamed according to a more standard naming
  1621 scheme (INCOMPATIBILITY):
  1622 
  1623   foo_inject:  "foo$x = foo$y ==> x = y"
  1624   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1625   foo_less:    "(foo$x << foo$y) = (x << y)"
  1626   foo_strict:  "foo$UU = UU"
  1627   foo_defined: "... ==> foo$x ~= UU"
  1628   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1629 
  1630 
  1631 *** ZF ***
  1632 
  1633 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1634 including the First Isomorphism Theorem (on quotienting by the kernel
  1635 of a homomorphism).
  1636 
  1637 * ZF/Simplifier: install second copy of type solver that actually
  1638 makes use of TC rules declared to Isar proof contexts (or locales);
  1639 the old version is still required for ML proof scripts.
  1640 
  1641 
  1642 *** Cube ***
  1643 
  1644 * Converted to Isar theory format; use locales instead of axiomatic
  1645 theories.
  1646 
  1647 
  1648 *** ML ***
  1649 
  1650 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1651 for ||>, ||>>, |>>,
  1652 
  1653 * Pure/library.ML no longer defines its own option datatype, but uses
  1654 that of the SML basis, which has constructors NONE and SOME instead of
  1655 None and Some, as well as exception Option.Option instead of OPTION.
  1656 The functions the, if_none, is_some, is_none have been adapted
  1657 accordingly, while Option.map replaces apsome.
  1658 
  1659 * Pure/library.ML: the exception LIST has been given up in favour of
  1660 the standard exceptions Empty and Subscript, as well as
  1661 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1662 superceded by the standard hd and tl functions etc.
  1663 
  1664 A number of basic list functions are no longer exported to the ML
  1665 toplevel, as they are variants of predefined functions.  The following
  1666 suggests how one can translate existing code:
  1667 
  1668     rev_append xs ys = List.revAppend (xs, ys)
  1669     nth_elem (i, xs) = List.nth (xs, i)
  1670     last_elem xs = List.last xs
  1671     flat xss = List.concat xss
  1672     seq fs = List.app fs
  1673     partition P xs = List.partition P xs
  1674     mapfilter f xs = List.mapPartial f xs
  1675 
  1676 * Pure/library.ML: several combinators for linear functional
  1677 transformations, notably reverse application and composition:
  1678 
  1679   x |> f                f #> g
  1680   (x, y) |-> f          f #-> g
  1681 
  1682 * Pure/library.ML: introduced/changed precedence of infix operators:
  1683 
  1684   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1685   infix 2 ?;
  1686   infix 3 o oo ooo oooo;
  1687   infix 4 ~~ upto downto;
  1688 
  1689 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1690 infix operators.
  1691 
  1692 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1693 fold_map support linear functional transformations and nesting.  For
  1694 example:
  1695 
  1696   fold f [x1, ..., xN] y =
  1697     y |> f x1 |> ... |> f xN
  1698 
  1699   (fold o fold) f [xs1, ..., xsN] y =
  1700     y |> fold f xs1 |> ... |> fold f xsN
  1701 
  1702   fold f [x1, ..., xN] =
  1703     f x1 #> ... #> f xN
  1704 
  1705   (fold o fold) f [xs1, ..., xsN] =
  1706     fold f xs1 #> ... #> fold f xsN
  1707 
  1708 * Pure/library.ML: the following selectors on type 'a option are
  1709 available:
  1710 
  1711   the:               'a option -> 'a  (*partial*)
  1712   these:             'a option -> 'a  where 'a = 'b list
  1713   the_default: 'a -> 'a option -> 'a
  1714   the_list:          'a option -> 'a list
  1715 
  1716 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1717 basic operations for association lists, following natural argument
  1718 order; moreover the explicit equality predicate passed here avoids
  1719 potentially expensive polymorphic runtime equality checks.
  1720 The old functions may be expressed as follows:
  1721 
  1722   assoc = uncurry (AList.lookup (op =))
  1723   assocs = these oo AList.lookup (op =)
  1724   overwrite = uncurry (AList.update (op =)) o swap
  1725 
  1726 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1727 
  1728   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1729   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1730 
  1731 replacing make_keylist and keyfilter (occassionally used)
  1732 Naive rewrites:
  1733 
  1734   make_keylist = AList.make
  1735   keyfilter = AList.find (op =)
  1736 
  1737 * eq_fst and eq_snd now take explicit equality parameter, thus
  1738   avoiding eqtypes. Naive rewrites:
  1739 
  1740     eq_fst = eq_fst (op =)
  1741     eq_snd = eq_snd (op =)
  1742 
  1743 * Removed deprecated apl and apr (rarely used).
  1744   Naive rewrites:
  1745 
  1746     apl (n, op) =>>= curry op n
  1747     apr (op, m) =>>= fn n => op (n, m)
  1748 
  1749 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1750 provides a reasonably efficient light-weight implementation of sets as
  1751 lists.
  1752 
  1753 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1754 few new operations; existing lookup and update are now curried to
  1755 follow natural argument order (for use with fold etc.);
  1756 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1757 
  1758 * Pure/General: output via the Isabelle channels of
  1759 writeln/warning/error etc. is now passed through Output.output, with a
  1760 hook for arbitrary transformations depending on the print_mode
  1761 (cf. Output.add_mode -- the first active mode that provides a output
  1762 function wins).  Already formatted output may be embedded into further
  1763 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1764 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1765 accommodate easy composition of diagnostic messages etc.  Programmers
  1766 rarely need to care about Output.output or Output.raw at all, with
  1767 some notable exceptions: Output.output is required when bypassing the
  1768 standard channels (writeln etc.), or in token translations to produce
  1769 properly formatted results; Output.raw is required when capturing
  1770 already output material that will eventually be presented to the user
  1771 a second time.  For the default print mode, both Output.output and
  1772 Output.raw have no effect.
  1773 
  1774 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1775 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1776 cumulative results are displayed at the end of a batch session.
  1777 
  1778 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1779 replaced by File.platform_path and File.shell_path (with appropriate
  1780 hooks).  This provides a clean interface for unusual systems where the
  1781 internal and external process view of file names are different.
  1782 
  1783 * Pure: more efficient orders for basic syntactic entities: added
  1784 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1785 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1786 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1787 orders now -- potential INCOMPATIBILITY for code that depends on a
  1788 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1789 Library.sort_strings on result).
  1790 
  1791 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1792 fold_types traverse types/terms from left to right, observing natural
  1793 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1794 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1795 
  1796 * Pure: name spaces have been refined, with significant changes of the
  1797 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1798 to extern(_table).  The plain name entry path is superceded by a
  1799 general 'naming' context, which also includes the 'policy' to produce
  1800 a fully qualified name and external accesses of a fully qualified
  1801 name; NameSpace.extend is superceded by context dependent
  1802 Sign.declare_name.  Several theory and proof context operations modify
  1803 the naming context.  Especially note Theory.restore_naming and
  1804 ProofContext.restore_naming to get back to a sane state; note that
  1805 Theory.add_path is no longer sufficient to recover from
  1806 Theory.absolute_path in particular.
  1807 
  1808 * Pure: new flags short_names (default false) and unique_names
  1809 (default true) for controlling output of qualified names.  If
  1810 short_names is set, names are printed unqualified.  If unique_names is
  1811 reset, the name prefix is reduced to the minimum required to achieve
  1812 the original result when interning again, even if there is an overlap
  1813 with earlier declarations.
  1814 
  1815 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1816 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1817 (useful for printing error messages).  INCOMPATIBILITY.
  1818 
  1819 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1820 Theory.theory are now identified, referring to the universal
  1821 Context.theory (see Pure/context.ML).  Actual signature and theory
  1822 content is managed as theory data.  The old code and interfaces were
  1823 spread over many files and structures; the new arrangement introduces
  1824 considerable INCOMPATIBILITY to gain more clarity:
  1825 
  1826   Context -- theory management operations (name, identity, inclusion,
  1827     parents, ancestors, merge, etc.), plus generic theory data;
  1828 
  1829   Sign -- logical signature and syntax operations (declaring consts,
  1830     types, etc.), plus certify/read for common entities;
  1831 
  1832   Theory -- logical theory operations (stating axioms, definitions,
  1833     oracles), plus a copy of logical signature operations (consts,
  1834     types, etc.); also a few basic management operations (Theory.copy,
  1835     Theory.merge, etc.)
  1836 
  1837 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1838 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1839 for convenience -- they merely return the theory.
  1840 
  1841 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1842 
  1843 * Pure: the Isar proof context type is already defined early in Pure
  1844 as Context.proof (note that ProofContext.context and Proof.context are
  1845 aliases, where the latter is the preferred name).  This enables other
  1846 Isabelle components to refer to that type even before Isar is present.
  1847 
  1848 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1849 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1850 any of these kinds.  For example, Sign.intern typeK is now
  1851 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1852 Theory.hide_types.  Also note that former
  1853 Theory.hide_classes/types/consts are now
  1854 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1855 internalize their arguments!  INCOMPATIBILITY.
  1856 
  1857 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1858 datatype thmref (with constructors Name and NameSelection) instead of
  1859 plain string -- INCOMPATIBILITY;
  1860 
  1861 * Pure: cases produced by proof methods specify options, where NONE
  1862 means to remove case bindings -- INCOMPATIBILITY in
  1863 (RAW_)METHOD_CASES.
  1864 
  1865 * Pure: the following operations retrieve axioms or theorems from a
  1866 theory node or theory hierarchy, respectively:
  1867 
  1868   Theory.axioms_of: theory -> (string * term) list
  1869   Theory.all_axioms_of: theory -> (string * term) list
  1870   PureThy.thms_of: theory -> (string * thm) list
  1871   PureThy.all_thms_of: theory -> (string * thm) list
  1872 
  1873 * Pure: print_tac now outputs the goal through the trace channel.
  1874 
  1875 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1876 Reference Toplevel.debug (default false) controls detailed printing
  1877 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1878 controls execution profiling -- set to 1 for time and 2 for space
  1879 (both increase the runtime).
  1880 
  1881 * Isar session: The initial use of ROOT.ML is now always timed,
  1882 i.e. the log will show the actual process times, in contrast to the
  1883 elapsed wall-clock time that the outer shell wrapper produces.
  1884 
  1885 * Simplifier: improved handling of bound variables (nameless
  1886 representation, avoid allocating new strings).  Simprocs that invoke
  1887 the Simplifier recursively should use Simplifier.inherit_bounds to
  1888 avoid local name clashes.  Failure to do so produces warnings
  1889 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1890 for further details.
  1891 
  1892 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1893 bindings for all theorems stored within a given theory; this may help
  1894 in porting non-Isar theories to Isar ones, while keeping ML proof
  1895 scripts for the time being.
  1896 
  1897 * ML operator HTML.with_charset specifies the charset begin used for
  1898 generated HTML files.  For example:
  1899 
  1900   HTML.with_charset "utf-8" use_thy "Hebrew";
  1901   HTML.with_charset "utf-8" use_thy "Chinese";
  1902 
  1903 
  1904 *** System ***
  1905 
  1906 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1907 isabelle, isatool etc.).
  1908 
  1909 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1910 isatool doc, isatool mkdir, display_drafts etc.).
  1911 
  1912 * isatool usedir: option -f allows specification of the ML file to be
  1913 used by Isabelle; default is ROOT.ML.
  1914 
  1915 * New isatool version outputs the version identifier of the Isabelle
  1916 distribution being used.
  1917 
  1918 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1919 (containing Boolean satisfiability problems) into Isabelle/HOL
  1920 theories.
  1921 
  1922 
  1923 
  1924 New in Isabelle2004 (April 2004)
  1925 --------------------------------
  1926 
  1927 *** General ***
  1928 
  1929 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1930   Replaces linorder.ML.
  1931 
  1932 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1933   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1934   (\<a>...\<z>), are now considered normal letters, and can therefore
  1935   be used anywhere where an ASCII letter (a...zA...Z) has until
  1936   now. COMPATIBILITY: This obviously changes the parsing of some
  1937   terms, especially where a symbol has been used as a binder, say
  1938   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1939   as an identifier.  Fix it by inserting a space around former
  1940   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1941   existing theory and ML files.
  1942 
  1943 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1944 
  1945 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1946   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1947   a normal (but invisible) letter. For multiple letter subscripts repeat
  1948   \<^isub> like this: x\<^isub>1\<^isub>2.
  1949 
  1950 * Pure: There are now sub-/superscripts that can span more than one
  1951   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1952   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1953   superscript. The new control characters are not identifier parts.
  1954 
  1955 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1956   content of "..." to the latex file instead of \isacntrl... . The "..."
  1957   may consist of any printable characters excluding the end bracket >.
  1958 
  1959 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1960   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1961   declare constants "final", which prevents their being given a definition
  1962   later.  It is useful for constants whose behaviour is fixed axiomatically
  1963   rather than definitionally, such as the meta-logic connectives.
  1964 
  1965 * Pure: 'instance' now handles general arities with general sorts
  1966   (i.e. intersections of classes),
  1967 
  1968 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1969   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1970   It can be changed to alter the colors/layout of generated pages.
  1971 
  1972 
  1973 *** Isar ***
  1974 
  1975 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1976   cut_tac, subgoal_tac and thin_tac:
  1977   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1978     locales are no longer forced to write Isar proof scripts.
  1979     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1980     emulations.
  1981   - INCOMPATIBILITY: names of variables to be instantiated may no
  1982     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1983     This is consistent with the instantiation attribute "where".
  1984 
  1985 * Attributes "where" and "of":
  1986   - Now take type variables of instantiated theorem into account when reading
  1987     the instantiation string.  This fixes a bug that caused instantiated
  1988     theorems to have too special types in some circumstances.
  1989   - "where" permits explicit instantiations of type variables.
  1990 
  1991 * Calculation commands "moreover" and "also" no longer interfere with
  1992   current facts ("this"), admitting arbitrary combinations with "then"
  1993   and derived forms.
  1994 
  1995 * Locales:
  1996   - Goal statements involving the context element "includes" no longer
  1997     generate theorems with internal delta predicates (those ending on
  1998     "_axioms") in the premise.
  1999     Resolve particular premise with <locale>.intro to obtain old form.
  2000   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2001     specification and "includes" elements in goal statement.
  2002   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2003     [intro?] and [elim?] (respectively) by default.
  2004   - Experimental command for instantiation of locales in proof contexts:
  2005         instantiate <label>[<attrs>]: <loc>
  2006     Instantiates locale <loc> and adds all its theorems to the current context
  2007     taking into account their attributes.  Label and attrs are optional
  2008     modifiers, like in theorem declarations.  If present, names of
  2009     instantiated theorems are qualified with <label>, and the attributes
  2010     <attrs> are applied after any attributes these theorems might have already.
  2011       If the locale has assumptions, a chained fact of the form
  2012     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2013     are derived.  The command does not support old-style locales declared
  2014     with "locale (open)".
  2015       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2016 
  2017 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2018   (Isar) contexts.
  2019 
  2020 
  2021 *** HOL ***
  2022 
  2023 * Proof import: new image HOL4 contains the imported library from
  2024   the HOL4 system with about 2500 theorems. It is imported by
  2025   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2026   can be used like any other Isabelle image.  See
  2027   HOL/Import/HOL/README for more information.
  2028 
  2029 * Simplifier:
  2030   - Much improved handling of linear and partial orders.
  2031     Reasoners for linear and partial orders are set up for type classes
  2032     "linorder" and "order" respectively, and are added to the default simpset
  2033     as solvers.  This means that the simplifier can build transitivity chains
  2034     to solve goals from the assumptions.
  2035   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2036     of blast or auto after simplification become unnecessary because the goal
  2037     is solved by simplification already.
  2038 
  2039 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2040     all proved in axiomatic type classes for semirings, rings and fields.
  2041 
  2042 * Numerics:
  2043   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2044     now formalized using the Ring_and_Field theory mentioned above.
  2045   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2046     than before, because now they are set up once in a generic manner.
  2047   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2048     Look for the general versions in Ring_and_Field (and Power if they concern
  2049     exponentiation).
  2050 
  2051 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2052 
  2053 * Records:
  2054   - Record types are now by default printed with their type abbreviation
  2055     instead of the list of all field types. This can be configured via
  2056     the reference "print_record_type_abbr".
  2057   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2058     (not enabled by default).
  2059   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2060     EX x. x = sel r to True (not enabled by default).
  2061   - Tactic "record_split_simp_tac" to split and simplify records added.
  2062 
  2063 * 'specification' command added, allowing for definition by
  2064   specification.  There is also an 'ax_specification' command that
  2065   introduces the new constants axiomatically.
  2066 
  2067 * arith(_tac) is now able to generate counterexamples for reals as well.
  2068 
  2069 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2070 
  2071 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2072   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2073 
  2074 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2075   matrix theory to linear programming.
  2076 
  2077 * Unions and Intersections:
  2078   The latex output syntax of UN and INT has been changed
  2079   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2080   i.e. the index formulae has become a subscript.
  2081   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2082 
  2083 * Unions and Intersections over Intervals:
  2084   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2085   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2086   like in normal math, and corresponding versions for < and for intersection.
  2087 
  2088 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2089   lexicographic dictonary ordering has been added as "lexord".
  2090 
  2091 * ML: the legacy theory structures Int and List have been removed. They had
  2092   conflicted with ML Basis Library structures having the same names.
  2093 
  2094 * 'refute' command added to search for (finite) countermodels.  Only works
  2095   for a fragment of HOL.  The installation of an external SAT solver is
  2096   highly recommended.  See "HOL/Refute.thy" for details.
  2097 
  2098 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2099   formulae under an assignment of free variables to random values.
  2100   In contrast to 'refute', it can deal with inductive datatypes,
  2101   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2102   for examples.
  2103 
  2104 
  2105 *** HOLCF ***
  2106 
  2107 * Streams now come with concatenation and are part of the HOLCF image
  2108 
  2109 
  2110 
  2111 New in Isabelle2003 (May 2003)
  2112 ------------------------------
  2113 
  2114 *** General ***
  2115 
  2116 * Provers/simplifier:
  2117 
  2118   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2119     Assumptions are now subject to complete mutual simplification,
  2120     not just from left to right. The simplifier now preserves
  2121     the order of assumptions.
  2122 
  2123     Potential INCOMPATIBILITY:
  2124 
  2125     -- simp sometimes diverges where the old version did
  2126        not, e.g. invoking simp on the goal
  2127 
  2128         [| P (f x); y = x; f x = f y |] ==> Q
  2129 
  2130        now gives rise to the infinite reduction sequence
  2131 
  2132         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2133 
  2134        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2135        kind of problem.
  2136 
  2137     -- Tactics combining classical reasoner and simplification (such as auto)
  2138        are also affected by this change, because many of them rely on
  2139        simp. They may sometimes diverge as well or yield a different numbers
  2140        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2141        in case of problems. Sometimes subsequent calls to the classical
  2142        reasoner will fail because a preceeding call to the simplifier too
  2143        eagerly simplified the goal, e.g. deleted redundant premises.
  2144 
  2145   - The simplifier trace now shows the names of the applied rewrite rules
  2146 
  2147   - You can limit the number of recursive invocations of the simplifier
  2148     during conditional rewriting (where the simplifie tries to solve the
  2149     conditions before applying the rewrite rule):
  2150     ML "simp_depth_limit := n"
  2151     where n is an integer. Thus you can force termination where previously
  2152     the simplifier would diverge.
  2153 
  2154   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2155 
  2156   - No longer aborts on failed congruence proof.  Instead, the
  2157     congruence is ignored.
  2158 
  2159 * Pure: New generic framework for extracting programs from constructive
  2160   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2161   as HOL/Extraction for some case studies.
  2162 
  2163 * Pure: The main goal of the proof state is no longer shown by default, only
  2164 the subgoals. This behaviour is controlled by a new flag.
  2165    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2166 (ML: Proof.show_main_goal).
  2167 
  2168 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2169 rules whose conclusion matches subgoal 1:
  2170       PG menu: Isabelle/Isar -> Show me -> matching rules
  2171 The rules are ordered by how closely they match the subgoal.
  2172 In particular, rules that solve a subgoal outright are displayed first
  2173 (or rather last, the way they are printed).
  2174 (ML: ProofGeneral.print_intros())
  2175 
  2176 * Pure: New flag trace_unify_fail causes unification to print
  2177 diagnostic information (PG: in trace buffer) when it fails. This is
  2178 useful for figuring out why single step proofs like rule, erule or
  2179 assumption failed.
  2180 
  2181 * Pure: Locale specifications now produce predicate definitions
  2182 according to the body of text (covering assumptions modulo local
  2183 definitions); predicate "loc_axioms" covers newly introduced text,
  2184 while "loc" is cumulative wrt. all included locale expressions; the
  2185 latter view is presented only on export into the global theory
  2186 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2187 on the old view without predicates;
  2188 
  2189 * Pure: predefined locales "var" and "struct" are useful for sharing
  2190 parameters (as in CASL, for example); just specify something like
  2191 ``var x + var y + struct M'' as import;
  2192 
  2193 * Pure: improved thms_containing: proper indexing of facts instead of
  2194 raw theorems; check validity of results wrt. current name space;
  2195 include local facts of proof configuration (also covers active
  2196 locales), cover fixed variables in index; may use "_" in term
  2197 specification; an optional limit for the number of printed facts may
  2198 be given (the default is 40);
  2199 
  2200 * Pure: disallow duplicate fact bindings within new-style theory files
  2201 (batch-mode only);
  2202 
  2203 * Provers: improved induct method: assumptions introduced by case
  2204 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2205 the goal statement); "foo" still refers to all facts collectively;
  2206 
  2207 * Provers: the function blast.overloaded has been removed: all constants
  2208 are regarded as potentially overloaded, which improves robustness in exchange
  2209 for slight decrease in efficiency;
  2210 
  2211 * Provers/linorder: New generic prover for transitivity reasoning over
  2212 linear orders.  Note: this prover is not efficient!
  2213 
  2214 * Isar: preview of problems to finish 'show' now produce an error
  2215 rather than just a warning (in interactive mode);
  2216 
  2217 
  2218 *** HOL ***
  2219 
  2220 * arith(_tac)
  2221 
  2222  - Produces a counter example if it cannot prove a goal.
  2223    Note that the counter example may be spurious if the goal is not a formula
  2224    of quantifier-free linear arithmetic.
  2225    In ProofGeneral the counter example appears in the trace buffer.
  2226 
  2227  - Knows about div k and mod k where k is a numeral of type nat or int.
  2228 
  2229  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2230    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2231    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2232 
  2233 * simp's arithmetic capabilities have been enhanced a bit: it now
  2234 takes ~= in premises into account (by performing a case split);
  2235 
  2236 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2237 are distributed over a sum of terms;
  2238 
  2239 * New tactic "trans_tac" and method "trans" instantiate
  2240 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2241 "<=", "<" and "=").
  2242 
  2243 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2244 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2245 
  2246 * 'typedef' command has new option "open" to suppress the set
  2247 definition;
  2248 
  2249 * functions Min and Max on finite sets have been introduced (theory
  2250 Finite_Set);
  2251 
  2252 * attribute [symmetric] now works for relations as well; it turns
  2253 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2254 
  2255 * induct over a !!-quantified statement (say !!x1..xn):
  2256   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2257 
  2258 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2259 %x. None. Warning: empty_def now refers to the previously hidden definition
  2260 of the empty set.
  2261 
  2262 * Algebra: formalization of classical algebra.  Intended as base for
  2263 any algebraic development in Isabelle.  Currently covers group theory
  2264 (up to Sylow's theorem) and ring theory (Universal Property of
  2265 Univariate Polynomials).  Contributions welcome;
  2266 
  2267 * GroupTheory: deleted, since its material has been moved to Algebra;
  2268 
  2269 * Complex: new directory of the complex numbers with numeric constants,
  2270 nonstandard complex numbers, and some complex analysis, standard and
  2271 nonstandard (Jacques Fleuriot);
  2272 
  2273 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2274 
  2275 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2276 Fleuriot);
  2277 
  2278 * Real/HahnBanach: updated and adapted to locales;
  2279 
  2280 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2281 Gray and Kramer);
  2282 
  2283 * UNITY: added the Meier-Sanders theory of progress sets;
  2284 
  2285 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2286 as abstract algorithms, instantiated to the JVM;
  2287 
  2288 * Bali: Java source language formalization. Type system, operational
  2289 semantics, axiomatic semantics. Supported language features:
  2290 classes, interfaces, objects,virtual methods, static methods,
  2291 static/instance fields, arrays, access modifiers, definite
  2292 assignment, exceptions.
  2293 
  2294 
  2295 *** ZF ***
  2296 
  2297 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2298 universe, etc.);
  2299 
  2300 * Main ZF: virtually all theories converted to new-style format;
  2301 
  2302 
  2303 *** ML ***
  2304 
  2305 * Pure: Tactic.prove provides sane interface for internal proofs;
  2306 omits the infamous "standard" operation, so this is more appropriate
  2307 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2308 
  2309 * Pure: improved error reporting of simprocs;
  2310 
  2311 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2312 up simprocs;
  2313 
  2314 
  2315 *** Document preparation ***
  2316 
  2317 * uses \par instead of \\ for line breaks in theory text. This may
  2318 shift some page breaks in large documents. To get the old behaviour
  2319 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2320 
  2321 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2322 other packages
  2323 
  2324 * \<euro> now needs package babel/greek instead of marvosym (which
  2325 broke \Rightarrow)
  2326 
  2327 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2328 textcomp package)
  2329 
  2330 
  2331 
  2332 New in Isabelle2002 (March 2002)
  2333 --------------------------------
  2334 
  2335 *** Document preparation ***
  2336 
  2337 * greatly simplified document preparation setup, including more
  2338 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2339 instructive isatool mkdir; users should basically be able to get
  2340 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2341 users may run a separate document processing stage manually like this:
  2342 "isatool usedir -D output HOL Test && isatool document Test/output";
  2343 
  2344 * theory dependency graph may now be incorporated into documents;
  2345 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2346 with \includegraphics of LaTeX;
  2347 
  2348 * proper spacing of consecutive markup elements, especially text
  2349 blocks after section headings;
  2350 
  2351 * support bold style (for single symbols only), input syntax is like
  2352 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2353 
  2354 * \<bullet> is now output as bold \cdot by default, which looks much
  2355 better in printed text;
  2356 
  2357 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2358 note that these symbols are currently unavailable in Proof General /
  2359 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2360 
  2361 * isatool latex no longer depends on changed TEXINPUTS, instead
  2362 isatool document copies the Isabelle style files to the target
  2363 location;
  2364 
  2365 
  2366 *** Isar ***
  2367 
  2368 * Pure/Provers: improved proof by cases and induction;
  2369   - 'case' command admits impromptu naming of parameters (such as
  2370     "case (Suc n)");
  2371   - 'induct' method divinates rule instantiation from the inductive
  2372     claim; no longer requires excessive ?P bindings for proper
  2373     instantiation of cases;
  2374   - 'induct' method properly enumerates all possibilities of set/type
  2375     rules; as a consequence facts may be also passed through *type*
  2376     rules without further ado;
  2377   - 'induct' method now derives symbolic cases from the *rulified*
  2378     rule (before it used to rulify cases stemming from the internal
  2379     atomized version); this means that the context of a non-atomic
  2380     statement becomes is included in the hypothesis, avoiding the
  2381     slightly cumbersome show "PROP ?case" form;
  2382   - 'induct' may now use elim-style induction rules without chaining
  2383     facts, using ``missing'' premises from the goal state; this allows
  2384     rules stemming from inductive sets to be applied in unstructured
  2385     scripts, while still benefitting from proper handling of non-atomic
  2386     statements; NB: major inductive premises need to be put first, all
  2387     the rest of the goal is passed through the induction;
  2388   - 'induct' proper support for mutual induction involving non-atomic
  2389     rule statements (uses the new concept of simultaneous goals, see
  2390     below);
  2391   - append all possible rule selections, but only use the first
  2392     success (no backtracking);
  2393   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2394   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2395   - added 'print_induct_rules' (covered by help item in recent Proof
  2396     General versions);
  2397   - moved induct/cases attributes to Pure, methods to Provers;
  2398   - generic method setup instantiated for FOL and HOL;
  2399 
  2400 * Pure: support multiple simultaneous goal statements, for example
  2401 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2402 meta-level mechanism, this acts as if several individual goals had
  2403 been stated separately; in particular common proof methods need to be
  2404 repeated in order to cover all claims; note that a single elimination
  2405 step is *not* sufficient to establish the two conjunctions, so this
  2406 fails:
  2407 
  2408   assume "A & B" then have A and B ..   (*".." fails*)
  2409 
  2410 better use "obtain" in situations as above; alternative refer to
  2411 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2412 
  2413 * Pure: proper integration with ``locales''; unlike the original
  2414 version by Florian Kammller, Isar locales package high-level proof
  2415 contexts rather than raw logical ones (e.g. we admit to include
  2416 attributes everywhere); operations on locales include merge and
  2417 rename; support for implicit arguments (``structures''); simultaneous
  2418 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2419 some examples;
  2420 
  2421 * Pure: the following commands have been ``localized'', supporting a
  2422 target locale specification "(in name)": 'lemma', 'theorem',
  2423 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2424 stored both within the locale and at the theory level (exported and
  2425 qualified by the locale name);
  2426 
  2427 * Pure: theory goals may now be specified in ``long'' form, with
  2428 ad-hoc contexts consisting of arbitrary locale elements. for example
  2429 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2430 definitions may be given, too); the result is a meta-level rule with
  2431 the context elements being discharged in the obvious way;
  2432 
  2433 * Pure: new proof command 'using' allows to augment currently used
  2434 facts after a goal statement ('using' is syntactically analogous to
  2435 'apply', but acts on the goal's facts only); this allows chained facts
  2436 to be separated into parts given before and after a claim, as in
  2437 ``from a and b have C using d and e <proof>'';
  2438 
  2439 * Pure: renamed "antecedent" case to "rule_context";
  2440 
  2441 * Pure: new 'judgment' command records explicit information about the
  2442 object-logic embedding (used by several tools internally); no longer
  2443 use hard-wired "Trueprop";
  2444 
  2445 * Pure: added 'corollary' command;
  2446 
  2447 * Pure: fixed 'token_translation' command;
  2448 
  2449 * Pure: removed obsolete 'exported' attribute;
  2450 
  2451 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2452 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2453 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2454 
  2455 * Pure: method 'atomize' presents local goal premises as object-level
  2456 statements (atomic meta-level propositions); setup controlled via
  2457 rewrite rules declarations of 'atomize' attribute; example
  2458 application: 'induct' method with proper rule statements in improper
  2459 proof *scripts*;
  2460 
  2461 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2462 now consider the syntactic context of assumptions, giving a better
  2463 chance to get type-inference of the arguments right (this is
  2464 especially important for locales);
  2465 
  2466 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2467 mode;
  2468 
  2469 * Pure/obtain: the formal conclusion "thesis", being marked as
  2470 ``internal'', may no longer be reference directly in the text;
  2471 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2472 situations;
  2473 
  2474 * Pure: generic 'sym' attribute which declares a rule both as pure
  2475 'elim?' and for the 'symmetric' operation;
  2476 
  2477 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2478 text; the fixed correlation with particular command syntax has been
  2479 discontinued;
  2480 
  2481 * Pure: new method 'rules' is particularly well-suited for proof
  2482 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2483 but often produces more compact proof terms with less detours;
  2484 
  2485 * Pure/Provers/classical: simplified integration with pure rule
  2486 attributes and methods; the classical "intro?/elim?/dest?"
  2487 declarations coincide with the pure ones; the "rule" method no longer
  2488 includes classically swapped intros; "intro" and "elim" methods no
  2489 longer pick rules from the context; also got rid of ML declarations
  2490 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2491 INCOMPATIBILITY;
  2492 
  2493 * Provers/classical: attribute 'swapped' produces classical inversions
  2494 of introduction rules;
  2495 
  2496 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2497 rules instead of full simplifier context; 'iff' attribute handles
  2498 conditional rules;
  2499 
  2500 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2501 
  2502 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2503 "(permissive)" option to recover old behavior;
  2504 
  2505 * HOL: 'inductive' no longer features separate (collective) attributes
  2506 for 'intros' (was found too confusing);
  2507 
  2508 * HOL: properly declared induction rules less_induct and
  2509 wf_induct_rule;
  2510 
  2511 
  2512 *** HOL ***
  2513 
  2514 * HOL: moved over to sane numeral syntax; the new policy is as
  2515 follows:
  2516 
  2517   - 0 and 1 are polymorphic constants, which are defined on any
  2518   numeric type (nat, int, real etc.);
  2519 
  2520   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2521   binary representation internally;
  2522 
  2523   - type nat has special constructor Suc, and generally prefers Suc 0
  2524   over 1::nat and Suc (Suc 0) over 2::nat;
  2525 
  2526 This change may cause significant problems of INCOMPATIBILITY; here
  2527 are some hints on converting existing sources:
  2528 
  2529   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2530   entities, so expressions involving "-" (unary or binary minus) need
  2531   to be spaced properly;
  2532 
  2533   - existing occurrences of "1" may need to be constraint "1::nat" or
  2534   even replaced by Suc 0; similar for old "2";
  2535 
  2536   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2537 
  2538   - remove all special provisions on numerals in proofs;
  2539 
  2540 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2541 representation (depends on bin_arith_simps in the default context);
  2542 
  2543 * HOL: symbolic syntax for x^2 (numeral 2);
  2544 
  2545 * HOL: the class of all HOL types is now called "type" rather than
  2546 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2547 in axclass/classes, instance/arities, and (usually rare) occurrences
  2548 in typings (of consts etc.); internally the class is called
  2549 "HOL.type", ML programs should refer to HOLogic.typeS;
  2550 
  2551 * HOL/record package improvements:
  2552   - new derived operations "fields" to build a partial record section,
  2553     "extend" to promote a fixed record to a record scheme, and
  2554     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2555     declared as simp by default;
  2556   - shared operations ("more", "fields", etc.) now need to be always
  2557     qualified) --- potential INCOMPATIBILITY;
  2558   - removed "make_scheme" operations (use "make" with "extend") --
  2559     INCOMPATIBILITY;
  2560   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2561   - provides cases/induct rules for use with corresponding Isar
  2562     methods (for concrete records, record schemes, concrete more
  2563     parts, and schematic more parts -- in that order);
  2564   - internal definitions directly based on a light-weight abstract
  2565     theory of product types over typedef rather than datatype;
  2566 
  2567 * HOL: generic code generator for generating executable ML code from
  2568 specifications; specific support for HOL constructs such as inductive
  2569 datatypes and sets, as well as recursive functions; can be invoked
  2570 via 'generate_code' theory section;
  2571 
  2572 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2573 
  2574 * HOL: consolidated and renamed several theories.  In particular:
  2575         Ord.thy has been absorbed into HOL.thy
  2576         String.thy has been absorbed into List.thy
  2577 
  2578 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2579 (beware of argument permutation!);
  2580 
  2581 * HOL: linorder_less_split superseded by linorder_cases;
  2582 
  2583 * HOL/List: "nodups" renamed to "distinct";
  2584 
  2585 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2586 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2587   - Ex_def has changed, now need to use some_eq_ex
  2588 
  2589 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2590 in this (rare) case use:
  2591 
  2592   delSWrapper "split_all_tac"
  2593   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2594 
  2595 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2596 MAY FAIL;
  2597 
  2598 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2599 Isabelle's type classes, ^ on functions and relations has too general
  2600 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2601 necessary to attach explicit type constraints;
  2602 
  2603 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2604 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2605 renamed accordingly (eg "compI" -> "rel_compI").
  2606 
  2607 * HOL: syntax translations now work properly with numerals and records
  2608 expressions;
  2609 
  2610 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2611 of "lam" -- INCOMPATIBILITY;
  2612 
  2613 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2614 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2615 renamed "Product_Type.unit";
  2616 
  2617 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2618 
  2619 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2620 the "cases" method);
  2621 
  2622 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2623 Florian Kammller);
  2624 
  2625 * HOL/IMP: updated and converted to new-style theory format; several
  2626 parts turned into readable document, with proper Isar proof texts and
  2627 some explanations (by Gerwin Klein);
  2628 
  2629 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2630 
  2631 * HOL-Hyperreal is now a logic image;
  2632 
  2633 
  2634 *** HOLCF ***
  2635 
  2636 * Isar: consts/constdefs supports mixfix syntax for continuous
  2637 operations;
  2638 
  2639 * Isar: domain package adapted to new-style theory format, e.g. see
  2640 HOLCF/ex/Dnat.thy;
  2641 
  2642 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2643 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2644 lift.induct_tac, always use UU instead of Undef;
  2645 
  2646 * HOLCF/IMP: updated and converted to new-style theory;
  2647 
  2648 
  2649 *** ZF ***
  2650 
  2651 * Isar: proper integration of logic-specific tools and packages,
  2652 including theory commands '(co)inductive', '(co)datatype',
  2653 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2654 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2655 
  2656 * theory Main no longer includes AC; for the Axiom of Choice, base
  2657 your theory on Main_ZFC;
  2658 
  2659 * the integer library now covers quotients and remainders, with many
  2660 laws relating division to addition, multiplication, etc.;
  2661 
  2662 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2663 typeless version of the formalism;
  2664 
  2665 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2666 format;
  2667 
  2668 * ZF/Induct: new directory for examples of inductive definitions,
  2669 including theory Multiset for multiset orderings; converted to
  2670 new-style theory format;
  2671 
  2672 * ZF: many new theorems about lists, ordinals, etc.;
  2673 
  2674 
  2675 *** General ***
  2676 
  2677 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2678 variable proof controls level of detail: 0 = no proofs (only oracle
  2679 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2680 also ref manual for further ML interfaces;
  2681 
  2682 * Pure/axclass: removed obsolete ML interface
  2683 goal_subclass/goal_arity;
  2684 
  2685 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2686 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2687 separate tokens, so expressions involving minus need to be spaced
  2688 properly;
  2689 
  2690 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2691 rather than "infixl" or "infixr";
  2692 
  2693 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2694 sort constraint specifications in type inference; e.g. "x::_::foo"
  2695 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2696 type variable);
  2697 
  2698 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2699 control output of nested => (types); the default behavior is
  2700 "type_brackets";
  2701 
  2702 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2703 tokens into AST constants;
  2704 
  2705 * Pure/syntax: prefer later declarations of translations and print
  2706 translation functions; potential INCOMPATIBILITY: need to reverse
  2707 multiple declarations for same syntax element constant;
  2708 
  2709 * Pure/show_hyps reset by default (in accordance to existing Isar
  2710 practice);
  2711 
  2712 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2713 addSafter;
  2714 
  2715 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2716 as well;
  2717 
  2718 * system: tested support for MacOS X; should be able to get Isabelle +
  2719 Proof General to work in a plain Terminal after installing Poly/ML
  2720 (e.g. from the Isabelle distribution area) and GNU bash alone
  2721 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2722 support requires further installations, e.g. from
  2723 http://fink.sourceforge.net/);
  2724 
  2725 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2726 
  2727 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2728 of 40 MB), cf. ML_OPTIONS;
  2729 
  2730 * system: Proof General keywords specification is now part of the
  2731 Isabelle distribution (see etc/isar-keywords.el);
  2732 
  2733 * system: support for persistent Proof General sessions (refrain from
  2734 outdating all loaded theories on startup); user may create writable
  2735 logic images like this: ``isabelle -q HOL Test'';
  2736 
  2737 * system: smart selection of Isabelle process versus Isabelle
  2738 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2739 run both "isabelle" and "Isabelle" even if file names are badly
  2740 damaged (executable inspects the case of the first letter of its own
  2741 name); added separate "isabelle-process" and "isabelle-interface";
  2742 
  2743 * system: refrain from any attempt at filtering input streams; no
  2744 longer support ``8bit'' encoding of old isabelle font, instead proper
  2745 iso-latin characters may now be used; the related isatools
  2746 "symbolinput" and "nonascii" have disappeared as well;
  2747 
  2748 * system: removed old "xterm" interface (the print modes "xterm" and
  2749 "xterm_color" are still available for direct use in a suitable
  2750 terminal);
  2751 
  2752 
  2753 
  2754 New in Isabelle99-2 (February 2001)
  2755 -----------------------------------
  2756 
  2757 *** Overview of INCOMPATIBILITIES ***
  2758 
  2759 * HOL: please note that theories in the Library and elsewhere often use the
  2760 new-style (Isar) format; to refer to their theorems in an ML script you must
  2761 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2762 
  2763 * HOL: inductive package no longer splits induction rule aggressively,
  2764 but only as far as specified by the introductions given; the old
  2765 format may be recovered via ML function complete_split_rule or attribute
  2766 'split_rule (complete)';
  2767 
  2768 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2769 gfp_Tarski to gfp_unfold;
  2770 
  2771 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2772 
  2773 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2774 relation); infix "^^" has been renamed "``"; infix "``" has been
  2775 renamed "`"; "univalent" has been renamed "single_valued";
  2776 
  2777 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2778 operation;
  2779 
  2780 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2781 
  2782 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2783 
  2784 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2785 consequence, it is no longer monotonic wrt. the local goal context
  2786 (which is now passed through the inductive cases);
  2787 
  2788 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2789 \<gg> to \<ggreater>;
  2790 
  2791 
  2792 *** Document preparation ***
  2793 
  2794 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2795 available: are "it" for near math-mode best-style output, "sl" for
  2796 slanted text style, and "tt" for plain type-writer; if no
  2797 \isabellestyle command is given, output is according to slanted
  2798 type-writer);
  2799 
  2800 * support sub/super scripts (for single symbols only), input syntax is
  2801 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2802 
  2803 * some more standard symbols; see Appendix A of the system manual for
  2804 the complete list of symbols defined in isabellesym.sty;
  2805 
  2806 * improved isabelle style files; more abstract symbol implementation
  2807 (should now use \isamath{...} and \isatext{...} in custom symbol
  2808 definitions);
  2809 
  2810 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2811 state; Note that presentation of goal states does not conform to
  2812 actual human-readable proof documents.  Please do not include goal
  2813 states into document output unless you really know what you are doing!
  2814 
  2815 * proper indentation of antiquoted output with proportional LaTeX
  2816 fonts;
  2817 
  2818 * no_document ML operator temporarily disables LaTeX document
  2819 generation;
  2820 
  2821 * isatool unsymbolize tunes sources for plain ASCII communication;
  2822 
  2823 
  2824 *** Isar ***
  2825 
  2826 * Pure: Isar now suffers initial goal statements to contain unbound
  2827 schematic variables (this does not conform to actual readable proof
  2828 documents, due to unpredictable outcome and non-compositional proof
  2829 checking); users who know what they are doing may use schematic goals
  2830 for Prolog-style synthesis of proven results;
  2831 
  2832 * Pure: assumption method (an implicit finishing) now handles actual
  2833 rules as well;
  2834 
  2835 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2836 initial goal, declare "that" only as Pure intro (only for single
  2837 steps); the "that" rule assumption may now be involved in implicit
  2838 finishing, thus ".." becomes a feasible for trivial obtains;
  2839 
  2840 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2841 instance proofs may be performed by "..";
  2842 
  2843 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2844 statements as well;
  2845 
  2846 * Pure: more robust selection of calculational rules;
  2847 
  2848 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2849 rule (as well as the assumption rule);
  2850 
  2851 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2852 lemmas, using the graph browser tool;
  2853 
  2854 * Pure: predict failure of "show" in interactive mode;
  2855 
  2856 * Pure: 'thms_containing' now takes actual terms as arguments;
  2857 
  2858 * HOL: improved method 'induct' --- now handles non-atomic goals
  2859 (potential INCOMPATIBILITY); tuned error handling;
  2860 
  2861 * HOL: cases and induct rules now provide explicit hints about the
  2862 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2863 any remaining facts are inserted into the goal verbatim;
  2864 
  2865 * HOL: local contexts (aka cases) may now contain term bindings as
  2866 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2867 the result to be shown in each case;
  2868 
  2869 * HOL: added 'recdef_tc' command;
  2870 
  2871 * isatool convert assists in eliminating legacy ML scripts;
  2872 
  2873 
  2874 *** HOL ***
  2875 
  2876 * HOL/Library: a collection of generic theories to be used together
  2877 with main HOL; the theory loader path already includes this directory
  2878 by default; the following existing theories have been moved here:
  2879 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2880 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2881 
  2882 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2883 modelling and verification task performed in Isabelle/HOL +
  2884 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2885 
  2886 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2887 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2888 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2889 'domain', this makes the theory consistent with mathematical
  2890 literature;
  2891 
  2892 * HOL basics: added overloaded operations "inverse" and "divide"
  2893 (infix "/"), syntax for generic "abs" operation, generic summation
  2894 operator \<Sum>;
  2895 
  2896 * HOL/typedef: simplified package, provide more useful rules (see also
  2897 HOL/subset.thy);
  2898 
  2899 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2900 now expressed as a proper nested rule (old-style tactic scripts may
  2901 require atomize_strip_tac to cope with non-atomic premises);
  2902 
  2903 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2904 to "split_conv" (old name still available for compatibility);
  2905 
  2906 * HOL: improved concrete syntax for strings (e.g. allows translation
  2907 rules with string literals);
  2908 
  2909 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2910  and Fleuriot's mechanization of analysis, including the transcendental
  2911  functions for the reals;
  2912 
  2913 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2914 
  2915 
  2916 *** CTT ***
  2917 
  2918 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2919 "lam" is displayed as TWO lambda-symbols
  2920 
  2921 * CTT: theory Main now available, containing everything (that is, Bool
  2922 and Arith);
  2923 
  2924 
  2925 *** General ***
  2926 
  2927 * Pure: the Simplifier has been implemented properly as a derived rule
  2928 outside of the actual kernel (at last!); the overall performance
  2929 penalty in practical applications is about 50%, while reliability of
  2930 the Isabelle inference kernel has been greatly improved;
  2931 
  2932 * print modes "brackets" and "no_brackets" control output of nested =>
  2933 (types) and ==> (props); the default behaviour is "brackets";
  2934 
  2935 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2936 as assumptions as well;
  2937 
  2938 * system: support Poly/ML 4.0;
  2939 
  2940 * system: isatool install handles KDE version 1 or 2;
  2941 
  2942 
  2943 
  2944 New in Isabelle99-1 (October 2000)
  2945 ----------------------------------
  2946 
  2947 *** Overview of INCOMPATIBILITIES ***
  2948 
  2949 * HOL: simplification of natural numbers is much changed; to partly
  2950 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2951 issue the following ML commands:
  2952 
  2953   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2954   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2955 
  2956 * HOL: simplification no longer dives into case-expressions; this is
  2957 controlled by "t.weak_case_cong" for each datatype t;
  2958 
  2959 * HOL: nat_less_induct renamed to less_induct;
  2960 
  2961 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2962 fixsome to patch .thy and .ML sources automatically;
  2963 
  2964   select_equality  -> some_equality
  2965   select_eq_Ex     -> some_eq_ex
  2966   selectI2EX       -> someI2_ex
  2967   selectI2         -> someI2
  2968   selectI          -> someI
  2969   select1_equality -> some1_equality
  2970   Eps_sym_eq       -> some_sym_eq_trivial
  2971   Eps_eq           -> some_eq_trivial
  2972 
  2973 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2974 
  2975 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2976 instead);
  2977 
  2978 * HOL: the recursion equations generated by 'recdef' are now called
  2979 f.simps instead of f.rules;
  2980 
  2981 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2982 
  2983 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2984 sometimes be needed;
  2985 
  2986 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2987 
  2988 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2989 
  2990 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2991 product is now "<*>" instead of "Times"; the lexicographic product is
  2992 now "<*lex*>" instead of "**";
  2993 
  2994 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2995 of main HOL, but was unused); better use HOL's datatype package;
  2996 
  2997 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2998 the old syntax may be recovered as follows:
  2999 
  3000   syntax (symbols)
  3001     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3002       (infixl "\\<oplus>" 100)
  3003 
  3004 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3005 
  3006 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3007 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3008 internally;
  3009 
  3010 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3011 changed from A/r to A//r;
  3012 
  3013 * ZF: new treatment of arithmetic (nat & int) may break some old
  3014 proofs;
  3015 
  3016 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3017 rulify -> rule_format, elimify -> elim_format, ...);
  3018 
  3019 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3020 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3021 should have to change intro!! to intro? only); replaced "delrule" by
  3022 "rule del";
  3023 
  3024 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3025 
  3026 * Provers: strengthened force_tac by using new first_best_tac;
  3027 
  3028 * LaTeX document preparation: several changes of isabelle.sty (see
  3029 lib/texinputs);
  3030 
  3031 
  3032 *** Document preparation ***
  3033 
  3034 * formal comments (text blocks etc.) in new-style theories may now
  3035 contain antiquotations of thm/prop/term/typ/text to be presented
  3036 according to latex print mode; concrete syntax is like this:
  3037 @{term[show_types] "f(x) = a + x"};
  3038 
  3039 * isatool mkdir provides easy setup of Isabelle session directories,
  3040 including proper document sources;
  3041 
  3042 * generated LaTeX sources are now deleted after successful run
  3043 (isatool document -c); may retain a copy somewhere else via -D option
  3044 of isatool usedir;
  3045 
  3046 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3047 style files, achieving self-contained LaTeX sources and simplifying
  3048 LaTeX debugging;
  3049 
  3050 * old-style theories now produce (crude) LaTeX output as well;
  3051 
  3052 * browser info session directories are now self-contained (may be put
  3053 on WWW server seperately); improved graphs of nested sessions; removed
  3054 graph for 'all sessions';
  3055 
  3056 * several improvements in isabelle style files; \isabellestyle{it}
  3057 produces fake math mode output; \isamarkupheader is now \section by
  3058 default; see lib/texinputs/isabelle.sty etc.;
  3059 
  3060 
  3061 *** Isar ***
  3062 
  3063 * Isar/Pure: local results and corresponding term bindings are now
  3064 subject to Hindley-Milner polymorphism (similar to ML); this
  3065 accommodates incremental type-inference very nicely;
  3066 
  3067 * Isar/Pure: new derived language element 'obtain' supports
  3068 generalized existence reasoning;
  3069 
  3070 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3071 support accumulation of results, without applying any rules yet;
  3072 useful to collect intermediate results without explicit name
  3073 references, and for use with transitivity rules with more than 2
  3074 premises;
  3075 
  3076 * Isar/Pure: scalable support for case-analysis type proofs: new
  3077 'case' language element refers to local contexts symbolically, as
  3078 produced by certain proof methods; internally, case names are attached
  3079 to theorems as "tags";
  3080 
  3081 * Isar/Pure: theory command 'hide' removes declarations from
  3082 class/type/const name spaces;
  3083 
  3084 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3085 indicate potential overloading;
  3086 
  3087 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3088 
  3089 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3090 "{a,b,c}" instead of {a,b,c};
  3091 
  3092 * Isar/Pure now provides its own version of intro/elim/dest
  3093 attributes; useful for building new logics, but beware of confusion
  3094 with the version in Provers/classical;
  3095 
  3096 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3097 case name 'antecedent';
  3098 
  3099 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3100 to the current context is now done automatically);
  3101 
  3102 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3103 for definining proof methods in ML;
  3104 
  3105 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3106 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3107 most cases, one should have to change intro!! to intro? only);
  3108 replaced "delrule" by "rule del";
  3109 
  3110 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3111 'symmetric' attribute (the latter supercedes [RS sym]);
  3112 
  3113 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3114 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3115 well (including splits);
  3116 
  3117 * Isar/Provers: Simplifier and Classical methods now support all kind
  3118 of modifiers used in the past, including 'cong', 'iff', etc.
  3119 
  3120 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3121 of Simplifier and Classical reasoner);
  3122 
  3123 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3124 now support named cases; major packages (inductive, datatype, primrec,
  3125 recdef) support case names and properly name parameters;
  3126 
  3127 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3128 monotonicity conditions are extracted to be proven at end of
  3129 calculations;
  3130 
  3131 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3132 method anyway;
  3133 
  3134 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3135 split_if split_if_asm; datatype package provides theorems foo.splits =
  3136 foo.split foo.split_asm for each datatype;
  3137 
  3138 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3139 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3140 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3141 use "(cases (simplified))" method in proper proof texts);
  3142 
  3143 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3144 
  3145 * Isar: names of theorems etc. may be natural numbers as well;
  3146 
  3147 * Isar: 'pr' command: optional arguments for goals_limit and
  3148 ProofContext.prems_limit; no longer prints theory contexts, but only
  3149 proof states;
  3150 
  3151 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3152 additional print modes to be specified; e.g. "pr(latex)" will print
  3153 proof state according to the Isabelle LaTeX style;
  3154 
  3155 * Isar: improved support for emulating tactic scripts, including proof
  3156 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3157 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3158 (for HOL datatypes);
  3159 
  3160 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3161 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3162 'proof method scripts' have to be in depth-first order;
  3163 
  3164 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3165 
  3166 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3167 should instead use individual commands for printing items
  3168 (print_commands, print_methods etc.);
  3169 
  3170 * Isar: added 'nothing' --- the empty list of theorems;
  3171 
  3172 
  3173 *** HOL ***
  3174 
  3175 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3176 corresponding virtual machine and a specification of its bytecode
  3177 verifier and a lightweight bytecode verifier, including proofs of
  3178 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3179 Cornelia Pusch (see also the homepage of project Bali at
  3180 http://isabelle.in.tum.de/Bali/);
  3181 
  3182 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3183 Clemens Ballarin;
  3184 
  3185 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3186 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3187 Rasmussen;
  3188 
  3189 * HOL/Lattice: fundamental concepts of lattice theory and order
  3190 structures, including duals, properties of bounds versus algebraic
  3191 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3192 Theorem for complete lattices etc.; may also serve as a demonstration
  3193 for abstract algebraic reasoning using axiomatic type classes, and
  3194 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3195 
  3196 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3197 von Oheimb;
  3198 
  3199 * HOL/IMPP: extension of IMP with local variables and mutually
  3200 recursive procedures, by David von Oheimb;
  3201 
  3202 * HOL/Lambda: converted into new-style theory and document;
  3203 
  3204 * HOL/ex/Multiquote: example of multiple nested quotations and
  3205 anti-quotations -- basically a generalized version of de-Bruijn
  3206 representation; very useful in avoiding lifting of operations;
  3207 
  3208 * HOL/record: added general record equality rule to simpset; fixed
  3209 select-update simplification procedure to handle extended records as
  3210 well; admit "r" as field name;
  3211 
  3212 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3213 other numeric types and also as the identity of groups, rings, etc.;
  3214 
  3215 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3216 Types nat and int belong to this axclass;
  3217 
  3218 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3219    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3220    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3221   two terms #m*u and #n*u are replaced by #(m+n)*u
  3222     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3223   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3224     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3225 
  3226 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3227 powerful prover for predicate logic but knows nothing of clasets; see
  3228 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3229 
  3230 * HOL: new version of "case_tac" subsumes both boolean case split and
  3231 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3232 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3233 
  3234 * HOL: simplification no longer dives into case-expressions: only the
  3235 selector expression is simplified, but not the remaining arms; to
  3236 enable full simplification of case-expressions for datatype t, you may
  3237 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3238 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3239 
  3240 * HOL/recdef: the recursion equations generated by 'recdef' for
  3241 function 'f' are now called f.simps instead of f.rules; if all
  3242 termination conditions are proved automatically, these simplification
  3243 rules are added to the simpset, as in primrec; rules may be named
  3244 individually as well, resulting in a separate list of theorems for
  3245 each equation;
  3246 
  3247 * HOL/While is a new theory that provides a while-combinator. It
  3248 permits the definition of tail-recursive functions without the
  3249 provision of a termination measure. The latter is necessary once the
  3250 invariant proof rule for while is applied.
  3251 
  3252 * HOL: new (overloaded) notation for the set of elements below/above
  3253 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3254 
  3255 * HOL: theorems impI, allI, ballI bound as "strip";
  3256 
  3257 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3258 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3259 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3260 
  3261 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3262 
  3263 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3264 main HOL, but was unused);
  3265 
  3266 * HOL: fewer consts declared as global (e.g. have to refer to
  3267 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3268 
  3269 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3270 in case of overlap with user translations (e.g. judgements over
  3271 tuples); (note that the underlying logical represenation is still
  3272 bogus);
  3273 
  3274 
  3275 *** ZF ***
  3276 
  3277 * ZF: simplification automatically cancels common terms in arithmetic
  3278 expressions over nat and int;
  3279 
  3280 * ZF: new treatment of nat to minimize type-checking: all operators
  3281 coerce their operands to a natural number using the function natify,
  3282 making the algebraic laws unconditional;
  3283 
  3284 * ZF: as above, for int: operators coerce their operands to an integer
  3285 using the function intify;
  3286 
  3287 * ZF: the integer library now contains many of the usual laws for the
  3288 orderings, including $<=, and monotonicity laws for $+ and $*;
  3289 
  3290 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3291 simplification;
  3292 
  3293 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3294 to the simplifier and classical reasoner simultaneously;
  3295 
  3296 
  3297 *** General ***
  3298 
  3299 * Provers: blast_tac now handles actual object-logic rules as
  3300 assumptions; note that auto_tac uses blast_tac internally as well;
  3301 
  3302 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3303 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3304 
  3305 * Provers: delrules now handles destruct rules as well (no longer need
  3306 explicit make_elim);
  3307 
  3308 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3309   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3310 use instead the strong form,
  3311   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3312 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3313 from destruct-rules;
  3314 
  3315 * Provers: Simplifier.easy_setup provides a fast path to basic
  3316 Simplifier setup for new object-logics;
  3317 
  3318 * Pure: AST translation rules no longer require constant head on LHS;
  3319 
  3320 * Pure: improved name spaces: ambiguous output is qualified; support
  3321 for hiding of names;
  3322 
  3323 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3324 XSYMBOL_HOME; no longer need to do manual configuration in most
  3325 situations;
  3326 
  3327 * system: compression of ML heaps images may now be controlled via -c
  3328 option of isabelle and isatool usedir (currently only observed by
  3329 Poly/ML);
  3330 
  3331 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3332 useful for remote X11);
  3333 
  3334 * system: provide TAGS file for Isabelle sources;
  3335 
  3336 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3337 order;
  3338 
  3339 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3340 timing flag supersedes proof_timing and Toplevel.trace;
  3341 
  3342 * ML: new combinators |>> and |>>> for incremental transformations
  3343 with secondary results (e.g. certain theory extensions):
  3344 
  3345 * ML: PureThy.add_defs gets additional argument to indicate potential
  3346 overloading (usually false);
  3347 
  3348 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3349 results;
  3350 
  3351 
  3352 
  3353 New in Isabelle99 (October 1999)
  3354 --------------------------------
  3355 
  3356 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3357 
  3358 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3359 are no longer simplified.  (This allows the simplifier to unfold recursive
  3360 functional programs.)  To restore the old behaviour, declare
  3361 
  3362     Delcongs [if_weak_cong];
  3363 
  3364 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3365 complement;
  3366 
  3367 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3368 
  3369 * HOL/datatype: mutual_induct_tac no longer exists --
  3370   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3371 
  3372 * HOL/typedef: fixed type inference for representing set; type
  3373 arguments now have to occur explicitly on the rhs as type constraints;
  3374 
  3375 * ZF: The con_defs part of an inductive definition may no longer refer
  3376 to constants declared in the same theory;
  3377 
  3378 * HOL, ZF: the function mk_cases, generated by the inductive
  3379 definition package, has lost an argument.  To simplify its result, it
  3380 uses the default simpset instead of a supplied list of theorems.
  3381 
  3382 * HOL/List: the constructors of type list are now Nil and Cons;
  3383 
  3384 * Simplifier: the type of the infix ML functions
  3385         setSSolver addSSolver setSolver addSolver
  3386 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3387 for packaging solvers. A solver is created via
  3388         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3389 where the string argument is only a comment.
  3390 
  3391 
  3392 *** Proof tools ***
  3393 
  3394 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3395 decision procedure for linear arithmetic. Currently it is used for
  3396 types `nat', `int', and `real' in HOL (see below); it can, should and
  3397 will be instantiated for other types and logics as well.
  3398 
  3399 * The simplifier now accepts rewrite rules with flexible heads, eg
  3400      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3401   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3402   matching.
  3403 
  3404 
  3405 *** General ***
  3406 
  3407 * New Isabelle/Isar subsystem provides an alternative to traditional
  3408 tactical theorem proving; together with the ProofGeneral/isar user
  3409 interface it offers an interactive environment for developing human
  3410 readable proof documents (Isar == Intelligible semi-automated
  3411 reasoning); for further information see isatool doc isar-ref,
  3412 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3413 
  3414 * improved and simplified presentation of theories: better HTML markup
  3415 (including colors), graph views in several sizes; isatool usedir now
  3416 provides a proper interface for user theories (via -P option); actual
  3417 document preparation based on (PDF)LaTeX is available as well (for
  3418 new-style theories only); see isatool doc system for more information;
  3419 
  3420 * native support for Proof General, both for classic Isabelle and
  3421 Isabelle/Isar;
  3422 
  3423 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3424 using the graph browser tool;
  3425 
  3426 * Isabelle manuals now also available as PDF;
  3427 
  3428 * theory loader rewritten from scratch (may not be fully
  3429 bug-compatible); old loadpath variable has been replaced by show_path,
  3430 add_path, del_path, reset_path functions; new operations such as
  3431 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3432 isatool doc ref);
  3433 
  3434 * improved isatool install: option -k creates KDE application icon,
  3435 option -p DIR installs standalone binaries;
  3436 
  3437 * added ML_PLATFORM setting (useful for cross-platform installations);
  3438 more robust handling of platform specific ML images for SML/NJ;
  3439 
  3440 * the settings environment is now statically scoped, i.e. it is never
  3441 created again in sub-processes invoked from isabelle, isatool, or
  3442 Isabelle;
  3443 
  3444 * path element specification '~~' refers to '$ISABELLE_HOME';
  3445 
  3446 * in locales, the "assumes" and "defines" parts may be omitted if
  3447 empty;
  3448 
  3449 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3450 long arrows);
  3451 
  3452 * new print_mode "HTML";
  3453 
  3454 * new flag show_tags controls display of tags of theorems (which are
  3455 basically just comments that may be attached by some tools);
  3456 
  3457 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3458 mode and goal output format:
  3459 
  3460 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3461 244c244
  3462 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3463 ---
  3464 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3465 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3466 181c181
  3467 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3468 ---
  3469 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3470 
  3471 * function bind_thms stores lists of theorems (cf. bind_thm);
  3472 
  3473 * new shorthand tactics ftac, eatac, datac, fatac;
  3474 
  3475 * qed (and friends) now accept "" as result name; in that case the
  3476 theorem is not stored, but proper checks and presentation of the
  3477 result still apply;
  3478 
  3479 * theorem database now also indexes constants "Trueprop", "all",
  3480 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3481 
  3482 
  3483 *** HOL ***
  3484 
  3485 ** HOL arithmetic **
  3486 
  3487 * There are now decision procedures for linear arithmetic over nat and
  3488 int:
  3489 
  3490 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3491 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3492 are treated as atomic; subformulae not involving type `nat' or `int'
  3493 are ignored; quantified subformulae are ignored unless they are
  3494 positive universal or negative existential. The tactic has to be
  3495 invoked by hand and can be a little bit slow. In particular, the
  3496 running time is exponential in the number of occurrences of `min' and
  3497 `max', and `-' on `nat'.
  3498 
  3499 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3500 (negated) (in)equalities among the premises and the conclusion into
  3501 account (i.e. no compound formulae) and does not know about `min' and
  3502 `max', and `-' on `nat'. It is fast and is used automatically by the
  3503 simplifier.
  3504 
  3505 NB: At the moment, these decision procedures do not cope with mixed
  3506 nat/int formulae where the two parts interact, such as `m < n ==>
  3507 int(m) < int(n)'.
  3508 
  3509 * HOL/Numeral provides a generic theory of numerals (encoded
  3510 efficiently as bit strings); setup for types nat/int/real is in place;
  3511 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3512 int, existing theories and proof scripts may require a few additional
  3513 type constraints;
  3514 
  3515 * integer division and remainder can now be performed on constant
  3516 arguments;
  3517 
  3518 * many properties of integer multiplication, division and remainder
  3519 are now available;
  3520 
  3521 * An interface to the Stanford Validity Checker (SVC) is available through the
  3522 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3523 are proved automatically.  SVC must be installed separately, and its results
  3524 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3525 invocation of the underlying oracle).  For SVC see
  3526   http://verify.stanford.edu/SVC
  3527 
  3528 * IsaMakefile: the HOL-Real target now builds an actual image;
  3529 
  3530 
  3531 ** HOL misc **
  3532 
  3533 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3534 (in Isabelle/Isar) -- by Gertrud Bauer;
  3535 
  3536 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3537 analysis for assembly languages with subtypes;
  3538 
  3539 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3540 -- avoids syntactic ambiguities and treats state, transition, and
  3541 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3542 changed syntax and (many) tactics;
  3543 
  3544 * HOL/inductive: Now also handles more general introduction rules such
  3545   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3546   theorems are now maintained within the theory (maintained via the
  3547   "mono" attribute);
  3548 
  3549 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3550   (using function types) such as
  3551 
  3552   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3553 
  3554 * HOL/record: record_simproc (part of the default simpset) takes care
  3555 of selectors applied to updated records; record_split_tac is no longer
  3556 part of the default claset; update_defs may now be removed from the
  3557 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3558 
  3559   claset_ref () := claset() addSWrapper record_split_wrapper;
  3560   Delsimprocs [record_simproc]
  3561 
  3562 * HOL/typedef: fixed type inference for representing set; type
  3563 arguments now have to occur explicitly on the rhs as type constraints;
  3564 
  3565 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3566 names rather than an ML expression;
  3567 
  3568 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3569 supplied later.  Program schemes can be defined, such as
  3570     "While B C s = (if B s then While B C (C s) else s)"
  3571 where the well-founded relation can be chosen after B and C have been given.
  3572 
  3573 * HOL/List: the constructors of type list are now Nil and Cons;
  3574 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3575 course, ML tools referring to List.list.op # etc. have to be adapted;
  3576 
  3577 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3578 disabled by default; run isabelle with option -m HOL to get back to
  3579 the original Gordon/HOL-style output;
  3580 
  3581 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3582 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3583 
  3584 * HOL basic syntax simplified (more orthogonal): all variants of
  3585 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3586 Eps operator is provided as well: "SOME x. P[x]";
  3587 
  3588 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3589 
  3590 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3591 thus available for user theories;
  3592 
  3593 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3594 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3595 time;
  3596 
  3597 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3598 several times and then mp;
  3599 
  3600 
  3601 *** LK ***
  3602 
  3603 * the notation <<...>> is now available as a notation for sequences of
  3604 formulas;
  3605 
  3606 * the simplifier is now installed
  3607 
  3608 * the axiom system has been generalized (thanks to Soren Heilmann)
  3609 
  3610 * the classical reasoner now has a default rule database
  3611 
  3612 
  3613 *** ZF ***
  3614 
  3615 * new primrec section allows primitive recursive functions to be given
  3616 directly (as in HOL) over datatypes and the natural numbers;
  3617 
  3618 * new tactics induct_tac and exhaust_tac for induction (or case
  3619 analysis) over datatypes and the natural numbers;
  3620 
  3621 * the datatype declaration of type T now defines the recursor T_rec;
  3622 
  3623 * simplification automatically does freeness reasoning for datatype
  3624 constructors;
  3625 
  3626 * automatic type-inference, with AddTCs command to insert new
  3627 type-checking rules;
  3628 
  3629 * datatype introduction rules are now added as Safe Introduction rules
  3630 to the claset;
  3631 
  3632 * the syntax "if P then x else y" is now available in addition to
  3633 if(P,x,y);
  3634 
  3635 
  3636 *** Internal programming interfaces ***
  3637 
  3638 * tuned simplifier trace output; new flag debug_simp;
  3639 
  3640 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3641 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3642 
  3643 * AxClass.axclass_tac lost the theory argument;
  3644 
  3645 * tuned current_goals_markers semantics: begin / end goal avoids
  3646 printing empty lines;
  3647 
  3648 * removed prs and prs_fn hook, which was broken because it did not
  3649 include \n in its semantics, forcing writeln to add one
  3650 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3651 string -> unit if you really want to output text without newline;
  3652 
  3653 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3654 plain output, interface builders may have to enable 'isabelle_font'
  3655 mode to get Isabelle font glyphs as before;
  3656 
  3657 * refined token_translation interface; INCOMPATIBILITY: output length
  3658 now of type real instead of int;
  3659 
  3660 * theory loader actions may be traced via new ThyInfo.add_hook
  3661 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3662 your own database of information attached to *whole* theories -- as
  3663 opposed to intra-theory data slots offered via TheoryDataFun;
  3664 
  3665 * proper handling of dangling sort hypotheses (at last!);
  3666 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3667 extra sort hypotheses that can be witnessed from the type signature;
  3668 the force_strip_shyps flag is gone, any remaining shyps are simply
  3669 left in the theorem (with a warning issued by strip_shyps_warning);
  3670 
  3671 
  3672 
  3673 New in Isabelle98-1 (October 1998)
  3674 ----------------------------------
  3675 
  3676 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3677 
  3678 * several changes of automated proof tools;
  3679 
  3680 * HOL: major changes to the inductive and datatype packages, including
  3681 some minor incompatibilities of theory syntax;
  3682 
  3683 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3684 called `inj_on';
  3685 
  3686 * HOL: removed duplicate thms in Arith:
  3687   less_imp_add_less  should be replaced by  trans_less_add1
  3688   le_imp_add_le      should be replaced by  trans_le_add1
  3689 
  3690 * HOL: unary minus is now overloaded (new type constraints may be
  3691 required);
  3692 
  3693 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3694 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3695 now taken as an integer constant.
  3696 
  3697 * Pure: ML function 'theory_of' renamed to 'theory';
  3698 
  3699 
  3700 *** Proof tools ***
  3701 
  3702 * Simplifier:
  3703   1. Asm_full_simp_tac is now more aggressive.
  3704      1. It will sometimes reorient premises if that increases their power to
  3705         simplify.
  3706      2. It does no longer proceed strictly from left to right but may also
  3707         rotate premises to achieve further simplification.
  3708      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3709      old Asm_full_simp_tac in that it does not rotate premises.
  3710   2. The simplifier now knows a little bit about nat-arithmetic.
  3711 
  3712 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3713 allows for selected deletion of wrappers, by introduction of names for
  3714 wrapper functionals.  This implies that addbefore, addSbefore,
  3715 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3716 and that adding two tactics with the same name overwrites the first
  3717 one (emitting a warning).
  3718   type wrapper = (int -> tactic) -> (int -> tactic)
  3719   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3720   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3721   delWrapper, delSWrapper: claset *  string            -> claset
  3722   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3723 
  3724 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3725 semantics; addbefore now affects only the unsafe part of step_tac
  3726 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3727 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3728 by Force_tac;
  3729 
  3730 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3731 compWrapper; added safe wrapper (and access functions for it);
  3732 
  3733 * HOL/split_all_tac is now much faster and fails if there is nothing
  3734 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3735 and the names of the automatically generated variables have changed.
  3736 split_all_tac has moved within claset() from unsafe wrappers to safe
  3737 wrappers, which means that !!-bound variables are split much more
  3738 aggressively, and safe_tac and clarify_tac now split such variables.
  3739 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3740 Note: the same holds for record_split_tac, which does the job of
  3741 split_all_tac for record fields.
  3742 
  3743 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3744 permanently to the default simpset using Addsplits just like
  3745 Addsimps. They can be removed via Delsplits just like
  3746 Delsimps. Lower-case versions are also available.
  3747 
  3748 * HOL/Simplifier: The rule split_if is now part of the default
  3749 simpset. This means that the simplifier will eliminate all occurrences
  3750 of if-then-else in the conclusion of a goal. To prevent this, you can
  3751 either remove split_if completely from the default simpset by
  3752 `Delsplits [split_if]' or remove it in a specific call of the
  3753 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3754 other case splitting rules to/from the default simpset: every datatype
  3755 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3756 t is the name of the datatype).
  3757 
  3758 * Classical reasoner / Simplifier combination: new force_tac (and
  3759 derivatives Force_tac, force) combines rewriting and classical
  3760 reasoning (and whatever other tools) similarly to auto_tac, but is
  3761 aimed to solve the given subgoal completely.
  3762 
  3763 
  3764 *** General ***
  3765 
  3766 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3767 and `goalw': the theory is no longer needed as an explicit argument -
  3768 the current theory context is used; assumptions are no longer returned
  3769 at the ML-level unless one of them starts with ==> or !!; it is
  3770 recommended to convert to these new commands using isatool fixgoal
  3771 (backup your sources first!);
  3772 
  3773 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3774 the current theory context, and 'theory' to lookup stored theories;
  3775 
  3776 * new theory section 'locale' for declaring constants, assumptions and
  3777 definitions that have local scope;
  3778 
  3779 * new theory section 'nonterminals' for purely syntactic types;
  3780 
  3781 * new theory section 'setup' for generic ML setup functions
  3782 (e.g. package initialization);
  3783 
  3784 * the distribution now includes Isabelle icons: see
  3785 lib/logo/isabelle-{small,tiny}.xpm;
  3786 
  3787 * isatool install - install binaries with absolute references to
  3788 ISABELLE_HOME/bin;
  3789 
  3790 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3791 
  3792 * print mode 'emacs' reserved for Isamode;
  3793 
  3794 * support multiple print (ast) translations per constant name;
  3795 
  3796 * theorems involving oracles are now printed with a suffixed [!];
  3797 
  3798 
  3799 *** HOL ***
  3800 
  3801 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3802 
  3803 * HOL/inductive package reorganized and improved: now supports mutual
  3804 definitions such as
  3805 
  3806   inductive EVEN ODD
  3807     intrs
  3808       null "0 : EVEN"
  3809       oddI "n : EVEN ==> Suc n : ODD"
  3810       evenI "n : ODD ==> Suc n : EVEN"
  3811 
  3812 new theorem list "elims" contains an elimination rule for each of the
  3813 recursive sets; inductive definitions now handle disjunctive premises
  3814 correctly (also ZF);
  3815 
  3816 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3817 "mutual_induct" no longer exists - the induction rule is always
  3818 contained in "induct";
  3819 
  3820 
  3821 * HOL/datatype package re-implemented and greatly improved: now
  3822 supports mutually recursive datatypes such as
  3823 
  3824   datatype
  3825     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3826             | SUM ('a aexp) ('a aexp)
  3827             | DIFF ('a aexp) ('a aexp)
  3828             | NUM 'a
  3829   and
  3830     'a bexp = LESS ('a aexp) ('a aexp)
  3831             | AND ('a bexp) ('a bexp)
  3832             | OR ('a bexp) ('a bexp)
  3833 
  3834 as well as indirectly recursive datatypes such as
  3835 
  3836   datatype
  3837     ('a, 'b) term = Var 'a
  3838                   | App 'b ((('a, 'b) term) list)
  3839 
  3840 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3841 induction on mutually / indirectly recursive datatypes.
  3842 
  3843 Primrec equations are now stored in theory and can be accessed via
  3844 <function_name>.simps.
  3845 
  3846 INCOMPATIBILITIES:
  3847 
  3848   - Theories using datatypes must now have theory Datatype as an
  3849     ancestor.
  3850   - The specific <typename>.induct_tac no longer exists - use the
  3851     generic induct_tac instead.
  3852   - natE has been renamed to nat.exhaust - use exhaust_tac
  3853     instead of res_inst_tac ... natE. Note that the variable
  3854     names in nat.exhaust differ from the names in natE, this
  3855     may cause some "fragile" proofs to fail.
  3856   - The theorems split_<typename>_case and split_<typename>_case_asm
  3857     have been renamed to <typename>.split and <typename>.split_asm.
  3858   - Since default sorts of type variables are now handled correctly,
  3859     some datatype definitions may have to be annotated with explicit
  3860     sort constraints.
  3861   - Primrec definitions no longer require function name and type
  3862     of recursive argument.
  3863 
  3864 Consider using isatool fixdatatype to adapt your theories and proof
  3865 scripts to the new package (backup your sources first!).
  3866 
  3867 
  3868 * HOL/record package: considerably improved implementation; now
  3869 includes concrete syntax for record types, terms, updates; theorems
  3870 for surjective pairing and splitting !!-bound record variables; proof
  3871 support is as follows:
  3872 
  3873   1) standard conversions (selectors or updates applied to record
  3874 constructor terms) are part of the standard simpset;
  3875 
  3876   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3877 made part of standard simpset and claset via addIffs;
  3878 
  3879   3) a tactic for record field splitting (record_split_tac) is part of
  3880 the standard claset (addSWrapper);
  3881 
  3882 To get a better idea about these rules you may retrieve them via
  3883 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3884 the name of your record type.
  3885 
  3886 The split tactic 3) conceptually simplifies by the following rule:
  3887 
  3888   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3889 
  3890 Thus any record variable that is bound by meta-all will automatically
  3891 blow up into some record constructor term, consequently the
  3892 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3893 solve record problems automatically.
  3894 
  3895 
  3896 * reorganized the main HOL image: HOL/Integ and String loaded by
  3897 default; theory Main includes everything;
  3898 
  3899 * automatic simplification of integer sums and comparisons, using cancellation;
  3900 
  3901 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3902 
  3903 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3904 
  3905 * many new identities for unions, intersections, set difference, etc.;
  3906 
  3907 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3908 called split_if, split_split, split_sum_case and split_nat_case (to go
  3909 with add/delsplits);
  3910 
  3911 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3912 (?x::unit) = (); this is made part of the default simpset, which COULD
  3913 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3914 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3915 unit_abs_eta_conv is added in order to counter the effect of
  3916 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3917 %u.f();
  3918 
  3919 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3920 makes more sense);
  3921 
  3922 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3923   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3924   disjointness reasoning but breaking a few old proofs.
  3925 
  3926 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3927 to 'converse' from 'inverse' (for compatibility with ZF and some
  3928 literature);
  3929 
  3930 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3931 the well-founded relation;
  3932 
  3933 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3934     Compl A.  The "Compl" syntax remains available as input syntax for this
  3935     release ONLY.
  3936 
  3937 * HOL/Update: new theory of function updates:
  3938     f(a:=b) == %x. if x=a then b else f x
  3939 may also be iterated as in f(a:=b,c:=d,...);
  3940 
  3941 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3942 
  3943 * HOL/List:
  3944   - new function list_update written xs[i:=v] that updates the i-th
  3945     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3946   - new function `upt' written [i..j(] which generates the list
  3947     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3948     bound write [i..j], which is a shorthand for [i..j+1(].
  3949   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3950 
  3951 * HOL/Arith:
  3952   - removed 'pred' (predecessor) function;
  3953   - generalized some theorems about n-1;
  3954   - many new laws about "div" and "mod";
  3955   - new laws about greatest common divisors (see theory ex/Primes);
  3956 
  3957 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3958 instead of "inverse";
  3959 
  3960 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3961   of the multiset ordering;
  3962 
  3963 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3964   (not included by default);
  3965 
  3966 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3967 
  3968 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3969   programs, i.e. different program variables may have different types.
  3970 
  3971 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3972   [previously, this check worked only if the rewrite rule was unconditional]
  3973   Now rew can involve either definitions or equalities (either == or =).
  3974 
  3975 
  3976 *** ZF ***
  3977 
  3978 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3979   only the theorems proved on ZF.ML;
  3980 
  3981 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3982   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3983   disjointness reasoning but breaking a few old proofs.
  3984 
  3985 * ZF/Update: new theory of function updates
  3986     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3987   may also be iterated as in f(a:=b,c:=d,...);
  3988 
  3989 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3990 
  3991 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3992   [previously, this check worked only if the rewrite rule was unconditional]
  3993   Now rew can involve either definitions or equalities (either == or =).
  3994 
  3995 * case_tac provided for compatibility with HOL
  3996     (like the old excluded_middle_tac, but with subgoals swapped)
  3997 
  3998 
  3999 *** Internal programming interfaces ***
  4000 
  4001 * Pure: several new basic modules made available for general use, see
  4002 also src/Pure/README;
  4003 
  4004 * improved the theory data mechanism to support encapsulation (data
  4005 kind name replaced by private Object.kind, acting as authorization
  4006 key); new type-safe user interface via functor TheoryDataFun; generic
  4007 print_data function becomes basically useless;
  4008 
  4009 * removed global_names compatibility flag -- all theory declarations
  4010 are qualified by default;
  4011 
  4012 * module Pure/Syntax now offers quote / antiquote translation
  4013 functions (useful for Hoare logic etc. with implicit dependencies);
  4014 see HOL/ex/Antiquote for an example use;
  4015 
  4016 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4017 cterm -> thm;
  4018 
  4019 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4020 subgoal;
  4021 
  4022 * Display.print_goals function moved to Locale.print_goals;
  4023 
  4024 * standard print function for goals supports current_goals_markers
  4025 variable for marking begin of proof, end of proof, start of goal; the
  4026 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4027 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4028 for example;
  4029 
  4030 
  4031 
  4032 New in Isabelle98 (January 1998)
  4033 --------------------------------
  4034 
  4035 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4036 
  4037 * changed lexical syntax of terms / types: dots made part of long
  4038 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4039 
  4040 * simpset (and claset) reference variable replaced by functions
  4041 simpset / simpset_ref;
  4042 
  4043 * no longer supports theory aliases (via merge) and non-trivial
  4044 implicit merge of thms' signatures;
  4045 
  4046 * most internal names of constants changed due to qualified names;
  4047 
  4048 * changed Pure/Sequence interface (see Pure/seq.ML);
  4049 
  4050 
  4051 *** General Changes ***
  4052 
  4053 * hierachically structured name spaces (for consts, types, axms, thms
  4054 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4055 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4056 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4057 long_names for fully qualified output names; NOTE: ML programs
  4058 (special tactics, packages etc.) referring to internal names may have
  4059 to be adapted to cope with fully qualified names; in case of severe
  4060 backward campatibility problems try setting 'global_names' at compile
  4061 time to have enrything declared within a flat name space; one may also
  4062 fine tune name declarations in theories via the 'global' and 'local'
  4063 section;
  4064 
  4065 * reimplemented the implicit simpset and claset using the new anytype
  4066 data filed in signatures; references simpset:simpset ref etc. are
  4067 replaced by functions simpset:unit->simpset and
  4068 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4069 to patch your ML files accordingly;
  4070 
  4071 * HTML output now includes theory graph data for display with Java
  4072 applet or isatool browser; data generated automatically via isatool
  4073 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4074 
  4075 * defs may now be conditional; improved rewrite_goals_tac to handle
  4076 conditional equations;
  4077 
  4078 * defs now admits additional type arguments, using TYPE('a) syntax;
  4079 
  4080 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4081 creates a new theory node; implicit merge of thms' signatures is
  4082 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4083 transfer:theory->thm->thm in (rare) cases;
  4084 
  4085 * improved handling of draft signatures / theories; draft thms (and
  4086 ctyps, cterms) are automatically promoted to real ones;
  4087 
  4088 * slightly changed interfaces for oracles: admit many per theory, named
  4089 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4090 
  4091 * print_goals: optional output of const types (set show_consts and
  4092 show_types);
  4093 
  4094 * improved output of warnings (###) and errors (***);
  4095 
  4096 * subgoal_tac displays a warning if the new subgoal has type variables;
  4097 
  4098 * removed old README and Makefiles;
  4099 
  4100 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4101 
  4102 * removed obsolete init_pps and init_database;
  4103 
  4104 * deleted the obsolete tactical STATE, which was declared by
  4105     fun STATE tacfun st = tacfun st st;
  4106 
  4107 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4108 (which abbreviates $HOME);
  4109 
  4110 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4111 use isatool fixseq to adapt your ML programs (this works for fully
  4112 qualified references to the Sequence structure only!);
  4113 
  4114 * use_thy no longer requires writable current directory; it always
  4115 reloads .ML *and* .thy file, if either one is out of date;
  4116 
  4117 
  4118 *** Classical Reasoner ***
  4119 
  4120 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4121 tactics that use classical reasoning to simplify a subgoal without
  4122 splitting it into several subgoals;
  4123 
  4124 * Safe_tac: like safe_tac but uses the default claset;
  4125 
  4126 
  4127 *** Simplifier ***
  4128 
  4129 * added simplification meta rules:
  4130     (asm_)(full_)simplify: simpset -> thm -> thm;
  4131 
  4132 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4133 logics (again);
  4134 
  4135 * added prems argument to simplification procedures;
  4136 
  4137 * HOL, FOL, ZF: added infix function `addsplits':
  4138   instead of `<simpset> setloop (split_tac <thms>)'
  4139   you can simply write `<simpset> addsplits <thms>'
  4140 
  4141 
  4142 *** Syntax ***
  4143 
  4144 * TYPE('a) syntax for type reflection terms;
  4145 
  4146 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4147 
  4148 * pretty printer: changed order of mixfix annotation preference (again!);
  4149 
  4150 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4151 
  4152 
  4153 *** HOL ***
  4154 
  4155 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4156   with `addloop' of the simplifier to faciliate case splitting in premises.
  4157 
  4158 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4159 
  4160 * HOL/Auth: new protocol proofs including some for the Internet
  4161   protocol TLS;
  4162 
  4163 * HOL/Map: new theory of `maps' a la VDM;
  4164 
  4165 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4166 cancelling out common nat summands from =, <, <= (in)equalities, or
  4167 differences; simplification procedures nat_cancel_factor for
  4168 cancelling common factor from =, <, <= (in)equalities over natural
  4169 sums; nat_cancel contains both kinds of procedures, it is installed by
  4170 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4171 
  4172 * HOL/simplifier: terms of the form
  4173   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4174   are rewritten to
  4175   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4176   and those of the form
  4177   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4178   are rewritten to
  4179   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4180 
  4181 * HOL/datatype
  4182   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4183 
  4184   P(t_case f1 ... fn x) =
  4185      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4186         ...
  4187        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4188      )
  4189 
  4190   and a theorem `split_t_case_asm' of the form
  4191 
  4192   P(t_case f1 ... fn x) =
  4193     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4194         ...
  4195        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4196      )
  4197   which can be added to a simpset via `addsplits'. The existing theorems
  4198   expand_list_case and expand_option_case have been renamed to
  4199   split_list_case and split_option_case.
  4200 
  4201 * HOL/Arithmetic:
  4202   - `pred n' is automatically converted to `n-1'.
  4203     Users are strongly encouraged not to use `pred' any longer,
  4204     because it will disappear altogether at some point.
  4205   - Users are strongly encouraged to write "0 < n" rather than
  4206     "n ~= 0". Theorems and proof tools have been modified towards this
  4207     `standard'.
  4208 
  4209 * HOL/Lists:
  4210   the function "set_of_list" has been renamed "set" (and its theorems too);
  4211   the function "nth" now takes its arguments in the reverse order and
  4212   has acquired the infix notation "!" as in "xs!n".
  4213 
  4214 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4215 
  4216 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4217   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4218 
  4219 * HOL/record: extensible records with schematic structural subtyping
  4220 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4221 still lacks various theorems and concrete record syntax;
  4222 
  4223 
  4224 *** HOLCF ***
  4225 
  4226 * removed "axioms" and "generated by" sections;
  4227 
  4228 * replaced "ops" section by extended "consts" section, which is capable of
  4229   handling the continuous function space "->" directly;
  4230 
  4231 * domain package:
  4232   . proves theorems immediately and stores them in the theory,
  4233   . creates hierachical name space,
  4234   . now uses normal mixfix annotations (instead of cinfix...),
  4235   . minor changes to some names and values (for consistency),
  4236   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4237   . separator between mutual domain defs: changed "," to "and",
  4238   . improved handling of sort constraints;  now they have to
  4239     appear on the left-hand side of the equations only;
  4240 
  4241 * fixed LAM <x,y,zs>.b syntax;
  4242 
  4243 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4244 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4245 
  4246 
  4247 *** FOL and ZF ***
  4248 
  4249 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4250   with `addloop' of the simplifier to faciliate case splitting in premises.
  4251 
  4252 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4253 in HOL, they strip ALL and --> from proved theorems;
  4254 
  4255 
  4256 
  4257 New in Isabelle94-8 (May 1997)
  4258 ------------------------------
  4259 
  4260 *** General Changes ***
  4261 
  4262 * new utilities to build / run / maintain Isabelle etc. (in parts
  4263 still somewhat experimental); old Makefiles etc. still functional;
  4264 
  4265 * new 'Isabelle System Manual';
  4266 
  4267 * INSTALL text, together with ./configure and ./build scripts;
  4268 
  4269 * reimplemented type inference for greater efficiency, better error
  4270 messages and clean internal interface;
  4271 
  4272 * prlim command for dealing with lots of subgoals (an easier way of
  4273 setting goals_limit);
  4274 
  4275 
  4276 *** Syntax ***
  4277 
  4278 * supports alternative (named) syntax tables (parser and pretty
  4279 printer); internal interface is provided by add_modesyntax(_i);
  4280 
  4281 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4282 be used in conjunction with the Isabelle symbol font; uses the
  4283 "symbols" syntax table;
  4284 
  4285 * added token_translation interface (may translate name tokens in
  4286 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4287 the current print_mode); IMPORTANT: user print translation functions
  4288 are responsible for marking newly introduced bounds
  4289 (Syntax.mark_boundT);
  4290 
  4291 * token translations for modes "xterm" and "xterm_color" that display
  4292 names in bold, underline etc. or colors (which requires a color
  4293 version of xterm);
  4294 
  4295 * infixes may now be declared with names independent of their syntax;
  4296 
  4297 * added typed_print_translation (like print_translation, but may
  4298 access type of constant);
  4299 
  4300 
  4301 *** Classical Reasoner ***
  4302 
  4303 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4304 some limitations.  Blast_tac...
  4305   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4306   + ignores elimination rules that don't have the correct format
  4307         (the conclusion MUST be a formula variable)
  4308   + ignores types, which can make HOL proofs fail
  4309   + rules must not require higher-order unification, e.g. apply_type in ZF
  4310     [message "Function Var's argument not a bound variable" relates to this]
  4311   + its proof strategy is more general but can actually be slower
  4312 
  4313 * substitution with equality assumptions no longer permutes other
  4314 assumptions;
  4315 
  4316 * minor changes in semantics of addafter (now called addaltern); renamed
  4317 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4318 (and access functions for it);
  4319 
  4320 * improved combination of classical reasoner and simplifier:
  4321   + functions for handling clasimpsets
  4322   + improvement of addss: now the simplifier is called _after_ the
  4323     safe steps.
  4324   + safe variant of addss called addSss: uses safe simplifications
  4325     _during_ the safe steps. It is more complete as it allows multiple
  4326     instantiations of unknowns (e.g. with slow_tac).
  4327 
  4328 *** Simplifier ***
  4329 
  4330 * added interface for simplification procedures (functions that
  4331 produce *proven* rewrite rules on the fly, depending on current
  4332 redex);
  4333 
  4334 * ordering on terms as parameter (used for ordered rewriting);
  4335 
  4336 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4337 
  4338 * the solver is now split into a safe and an unsafe part.
  4339 This should be invisible for the normal user, except that the
  4340 functions setsolver and addsolver have been renamed to setSolver and
  4341 addSolver; added safe_asm_full_simp_tac;
  4342 
  4343 
  4344 *** HOL ***
  4345 
  4346 * a generic induction tactic `induct_tac' which works for all datatypes and
  4347 also for type `nat';
  4348 
  4349 * a generic case distinction tactic `exhaust_tac' which works for all
  4350 datatypes and also for type `nat';
  4351 
  4352 * each datatype comes with a function `size';
  4353 
  4354 * patterns in case expressions allow tuple patterns as arguments to
  4355 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4356 
  4357 * primrec now also works with type nat;
  4358 
  4359 * recdef: a new declaration form, allows general recursive functions to be
  4360 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4361 
  4362 * the constant for negation has been renamed from "not" to "Not" to
  4363 harmonize with FOL, ZF, LK, etc.;
  4364 
  4365 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4366 infinite lists;
  4367 
  4368 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4369 
  4370 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4371 problems in commutative rings, using axiomatic type classes for + and *;
  4372 
  4373 * more examples in HOL/MiniML and HOL/Auth;
  4374 
  4375 * more default rewrite rules for quantifiers, union/intersection;
  4376 
  4377 * a new constant `arbitrary == @x.False';
  4378 
  4379 * HOLCF/IOA replaces old HOL/IOA;
  4380 
  4381 * HOLCF changes: derived all rules and arities
  4382   + axiomatic type classes instead of classes
  4383   + typedef instead of faking type definitions
  4384   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4385   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4386   + eliminated the types void, one, tr
  4387   + use unit lift and bool lift (with translations) instead of one and tr
  4388   + eliminated blift from Lift3.thy (use Def instead of blift)
  4389   all eliminated rules are derived as theorems --> no visible changes ;
  4390 
  4391 
  4392 *** ZF ***
  4393 
  4394 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4395 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4396 as ZF_cs addSIs [equalityI];
  4397 
  4398 
  4399 
  4400 New in Isabelle94-7 (November 96)
  4401 ---------------------------------
  4402 
  4403 * allowing negative levels (as offsets) in prlev and choplev;
  4404 
  4405 * super-linear speedup for large simplifications;
  4406 
  4407 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4408 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4409 FAIL); can suppress it using the command Delsimps (ex_simps @
  4410 all_simps); De Morgan laws are also now included, by default;
  4411 
  4412 * improved printing of ==>  :  ~:
  4413 
  4414 * new object-logic "Sequents" adds linear logic, while replacing LK
  4415 and Modal (thanks to Sara Kalvala);
  4416 
  4417 * HOL/Auth: correctness proofs for authentication protocols;
  4418 
  4419 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4420 examples on HOL/Auth);
  4421 
  4422 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4423 the rewriter and classical reasoner simultaneously;
  4424 
  4425 * function uresult no longer returns theorems in "standard" format;
  4426 regain previous version by: val uresult = standard o uresult;
  4427 
  4428 
  4429 
  4430 New in Isabelle94-6
  4431 -------------------
  4432 
  4433 * oracles -- these establish an interface between Isabelle and trusted
  4434 external reasoners, which may deliver results as theorems;
  4435 
  4436 * proof objects (in particular record all uses of oracles);
  4437 
  4438 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4439 
  4440 * "constdefs" section in theory files;
  4441 
  4442 * "primrec" section (HOL) no longer requires names;
  4443 
  4444 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4445 
  4446 
  4447 
  4448 New in Isabelle94-5
  4449 -------------------
  4450 
  4451 * reduced space requirements;
  4452 
  4453 * automatic HTML generation from theories;
  4454 
  4455 * theory files no longer require "..." (quotes) around most types;
  4456 
  4457 * new examples, including two proofs of the Church-Rosser theorem;
  4458 
  4459 * non-curried (1994) version of HOL is no longer distributed;
  4460 
  4461 
  4462 
  4463 New in Isabelle94-4
  4464 -------------------
  4465 
  4466 * greatly reduced space requirements;
  4467 
  4468 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4469 
  4470 * searchable theorem database (see the section "Retrieving theorems" on
  4471 page 8 of the Reference Manual);
  4472 
  4473 * new examples, including Grabczewski's monumental case study of the
  4474 Axiom of Choice;
  4475 
  4476 * The previous version of HOL renamed to Old_HOL;
  4477 
  4478 * The new version of HOL (previously called CHOL) uses a curried syntax
  4479 for functions.  Application looks like f a b instead of f(a,b);
  4480 
  4481 * Mutually recursive inductive definitions finally work in HOL;
  4482 
  4483 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4484 translates to the operator "split";
  4485 
  4486 
  4487 
  4488 New in Isabelle94-3
  4489 -------------------
  4490 
  4491 * new infix operator, addss, allowing the classical reasoner to
  4492 perform simplification at each step of its search.  Example:
  4493         fast_tac (cs addss ss)
  4494 
  4495 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4496 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4497 look like (a,b) instead of <a,b>;
  4498 
  4499 * PLEASE NOTE: CHOL will eventually replace HOL!
  4500 
  4501 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4502 It translates to the operator "split".  A new theory of integers is available;
  4503 
  4504 * In ZF, integer numerals now denote two's-complement binary integers.
  4505 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4506 
  4507 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4508 of the Axiom of Choice;
  4509 
  4510 
  4511 
  4512 New in Isabelle94-2
  4513 -------------------
  4514 
  4515 * Significantly faster resolution;
  4516 
  4517 * the different sections in a .thy file can now be mixed and repeated
  4518 freely;
  4519 
  4520 * Database of theorems for FOL, HOL and ZF.  New
  4521 commands including qed, qed_goal and bind_thm store theorems in the database.
  4522 
  4523 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4524 a given theory (thms_of), or find out what theory a theorem was proved in
  4525 (theory_of_thm);
  4526 
  4527 * Bugs fixed in the inductive definition and datatype packages;
  4528 
  4529 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4530 and HOL_dup_cs obsolete;
  4531 
  4532 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4533 have been removed;
  4534 
  4535 * Simpler definition of function space in ZF;
  4536 
  4537 * new results about cardinal and ordinal arithmetic in ZF;
  4538 
  4539 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4540 types;
  4541 
  4542 
  4543 $Id$