NEWS
author wenzelm
Sun Jan 21 17:13:30 2007 +0100 (2007-01-21)
changeset 22151 511f7fb8469e
parent 22138 b9cbcd8be40f
child 22152 df787d582323
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 * ML within Isar: antiquotations allow to embed statically-checked
   754 formal entities in the source, referring to the context available at
   755 compile-time.  For example:
   756 
   757 ML {* @{typ "'a => 'b"} *}
   758 ML {* @{term "%x. x"} *}
   759 ML {* @{prop "x == y"} *}
   760 ML {* @{ctyp "'a => 'b"} *}
   761 ML {* @{cterm "%x. x"} *}
   762 ML {* @{cprop "x == y"} *}
   763 ML {* @{thm asm_rl} *}
   764 ML {* @{thms asm_rl} *}
   765 ML {* @{context} *}
   766 ML {* @{theory} *}
   767 ML {* @{theory Pure} *}
   768 ML {* @{simpset} *}
   769 ML {* @{claset} *}
   770 ML {* @{clasimpset} *}
   771 
   772 The same works for sources being ``used'' within an Isar context.
   773 
   774 * Pure/library:
   775 
   776   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   777   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   778 
   779 The semantics of "burrow" is: "take a function with *simulatanously*
   780 transforms a list of value, and apply it *simulatanously* to a list of
   781 list of values of the appropriate type". Compare this with "map" which
   782 would *not* apply its argument function simulatanously but in
   783 sequence; "fold_burrow" has an additional context.
   784 
   785 * Pure/library: functions map2 and fold2 with curried syntax for
   786 simultanous mapping and folding:
   787 
   788     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   789     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   790 
   791 * Pure/library: indexed lists - some functions in the Isabelle library
   792 treating lists over 'a as finite mappings from [0...n] to 'a have been
   793 given more convenient names and signatures reminiscent of similar
   794 functions for alists, tables, etc:
   795 
   796   val nth: 'a list -> int -> 'a 
   797   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   798   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   799 
   800 Note that fold_index starts counting at index 0, not 1 like foldln
   801 used to.
   802 
   803 * Pure/library: added general ``divide_and_conquer'' combinator on
   804 lists.
   805 
   806 * Pure/General/table.ML: the join operations now works via exceptions
   807 DUP/SAME instead of type option.  This is simpler in simple cases, and
   808 admits slightly more efficient complex applications.
   809 
   810 * Pure: datatype Context.generic joins theory/Proof.context and
   811 provides some facilities for code that works in either kind of
   812 context, notably GenericDataFun for uniform theory and proof data.
   813 
   814 * Pure: 'advanced' translation functions (parse_translation etc.) now
   815 use Context.generic instead of just theory.
   816 
   817 * Pure: simplified internal attribute type, which is now always
   818 Context.generic * thm -> Context.generic * thm.  Global (theory)
   819 vs. local (Proof.context) attributes have been discontinued, while
   820 minimizing code duplication.  Thm.rule_attribute and
   821 Thm.declaration_attribute build canonical attributes; see also
   822 structure Context for further operations on Context.generic, notably
   823 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
   824 declarations and definitions.
   825 
   826 * Pure/kernel: consts certification ignores sort constraints given in
   827 signature declarations.  (This information is not relevant to the
   828 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
   829 potential INCOMPATIBILITY.
   830 
   831 * Pure: axiomatic type classes are now purely definitional, with
   832 explicit proofs of class axioms and super class relations performed
   833 internally.  See Pure/axclass.ML for the main internal interfaces --
   834 notably AxClass.define_class supercedes AxClass.add_axclass, and
   835 AxClass.axiomatize_class/classrel/arity supercede
   836 Sign.add_classes/classrel/arities.
   837 
   838 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
   839 global/local versions on theory vs. Proof.context have been
   840 discontinued; Attrib.syntax and Method.syntax have been adapted
   841 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
   842 attributes, methods, etc.
   843 
   844 * Pure: several functions of signature "... -> theory -> theory * ..."
   845 have been reoriented to "... -> theory -> ... * theory" in order to
   846 allow natural usage in combination with the ||>, ||>>, |-> and
   847 fold_map combinators.
   848 
   849 * Pure: official theorem names (closed derivations) and additional
   850 comments (tags) are now strictly separate.  Name hints -- which are
   851 maintained as tags -- may be attached any time without affecting the
   852 derivation.
   853 
   854 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   855 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   856 achieve the old behaviour.
   857 
   858 * Pure: the "Goal" constant is now called "prop", supporting a
   859 slightly more general idea of ``protecting'' meta-level rule
   860 statements.
   861 
   862 * Pure: Logic.(un)varify only works in a global context, which is now
   863 enforced instead of silently assumed.  INCOMPATIBILITY, may use
   864 Logic.legacy_(un)varify as temporary workaround.
   865 
   866 * Pure: structure Name provides scalable operations for generating
   867 internal variable names, notably Name.variants etc.  This replaces
   868 some popular functions from term.ML:
   869 
   870   Term.variant		->  Name.variant
   871   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
   872   Term.invent_names	->  Name.invent_list
   873 
   874 Note that low-level renaming rarely occurs in new code -- operations
   875 from structure Variable are used instead (see below).
   876 
   877 * Pure: structure Variable provides fundamental operations for proper
   878 treatment of fixed/schematic variables in a context.  For example,
   879 Variable.import introduces fixes for schematics of given facts and
   880 Variable.export reverses the effect (up to renaming) -- this replaces
   881 various freeze_thaw operations.
   882 
   883 * Pure: structure Goal provides simple interfaces for
   884 init/conclude/finish and tactical prove operations (replacing former
   885 Tactic.prove).  Goal.prove is the canonical way to prove results
   886 within a given context; Goal.prove_global is a degraded version for
   887 theory level goals, including a global Drule.standard.  Note that
   888 OldGoals.prove_goalw_cterm has long been obsolete, since it is
   889 ill-behaved in a local proof context (e.g. with local fixes/assumes or
   890 in a locale context).
   891 
   892 * Isar: simplified treatment of user-level errors, using exception
   893 ERROR of string uniformly.  Function error now merely raises ERROR,
   894 without any side effect on output channels.  The Isar toplevel takes
   895 care of proper display of ERROR exceptions.  ML code may use plain
   896 handle/can/try; cat_error may be used to concatenate errors like this:
   897 
   898   ... handle ERROR msg => cat_error msg "..."
   899 
   900 Toplevel ML code (run directly or through the Isar toplevel) may be
   901 embedded into the Isar toplevel with exception display/debug like
   902 this:
   903 
   904   Isar.toplevel (fn () => ...)
   905 
   906 INCOMPATIBILITY, removed special transform_error facilities, removed
   907 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   908 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   909 -- use plain ERROR instead.
   910 
   911 * Isar: theory setup now has type (theory -> theory), instead of a
   912 list.  INCOMPATIBILITY, may use #> to compose setup functions.
   913 
   914 * Isar: installed ML toplevel pretty printer for type Proof.context,
   915 subject to ProofContext.debug/verbose flags.
   916 
   917 * Isar: Toplevel.theory_to_proof admits transactions that modify the
   918 theory before entering a proof state.  Transactions now always see a
   919 quasi-functional intermediate checkpoint, both in interactive and
   920 batch mode.
   921 
   922 * Simplifier: the simpset of a running simplification process now
   923 contains a proof context (cf. Simplifier.the_context), which is the
   924 very context that the initial simpset has been retrieved from (by
   925 simpset_of/local_simpset_of).  Consequently, all plug-in components
   926 (solver, looper etc.) may depend on arbitrary proof data.
   927 
   928 * Simplifier.inherit_context inherits the proof context (plus the
   929 local bounds) of the current simplification process; any simproc
   930 etc. that calls the Simplifier recursively should do this!  Removed
   931 former Simplifier.inherit_bounds, which is already included here --
   932 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   933 specify an explicit context using Simplifier.context/theory_context.
   934 
   935 * Simplifier/Classical Reasoner: more abstract interfaces
   936 change_simpset/claset for modifying the simpset/claset reference of a
   937 theory; raw versions simpset/claset_ref etc. have been discontinued --
   938 INCOMPATIBILITY.
   939 
   940 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   941 "Trueprop" etc.
   942 
   943 
   944 *** System ***
   945 
   946 * settings: ML_IDENTIFIER -- which is appended to user specific heap
   947 locations -- now includes the Isabelle version identifier as well.
   948 This simplifies use of multiple Isabelle installations.
   949 
   950 * isabelle-process: option -S (secure mode) disables some critical
   951 operations, notably runtime compilation and evaluation of ML source
   952 code.
   953 
   954 
   955 New in Isabelle2005 (October 2005)
   956 ----------------------------------
   957 
   958 *** General ***
   959 
   960 * Theory headers: the new header syntax for Isar theories is
   961 
   962   theory <name>
   963   imports <theory1> ... <theoryN>
   964   uses <file1> ... <fileM>
   965   begin
   966 
   967 where the 'uses' part is optional.  The previous syntax
   968 
   969   theory <name> = <theory1> + ... + <theoryN>:
   970 
   971 will disappear in the next release.  Use isatool fixheaders to convert
   972 existing theory files.  Note that there is no change in ancient
   973 non-Isar theories now, but these will disappear soon.
   974 
   975 * Theory loader: parent theories can now also be referred to via
   976 relative and absolute paths.
   977 
   978 * Command 'find_theorems' searches for a list of criteria instead of a
   979 list of constants. Known criteria are: intro, elim, dest, name:string,
   980 simp:term, and any term. Criteria can be preceded by '-' to select
   981 theorems that do not match. Intro, elim, dest select theorems that
   982 match the current goal, name:s selects theorems whose fully qualified
   983 name contain s, and simp:term selects all simplification rules whose
   984 lhs match term.  Any other term is interpreted as pattern and selects
   985 all theorems matching the pattern. Available in ProofGeneral under
   986 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   987 
   988   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   989 
   990 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   991 matching the current goal as introduction rule and not having "HOL."
   992 in their name (i.e. not being defined in theory HOL).
   993 
   994 * Command 'thms_containing' has been discontinued in favour of
   995 'find_theorems'; INCOMPATIBILITY.
   996 
   997 * Communication with Proof General is now 8bit clean, which means that
   998 Unicode text in UTF-8 encoding may be used within theory texts (both
   999 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1000 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1001 
  1002   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1003   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1004 
  1005 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1006 Classical Reasoner.  Typical big applications run around 2 times
  1007 faster.
  1008 
  1009 
  1010 *** Document preparation ***
  1011 
  1012 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1013 of raw sources.  Only those symbols that do not require additional
  1014 LaTeX packages (depending on comments in isabellesym.sty) are
  1015 displayed properly, everything else is left verbatim.  isatool display
  1016 and isatool print are used as front ends (these are subject to the
  1017 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1018 
  1019 * Command tags control specific markup of certain regions of text,
  1020 notably folding and hiding.  Predefined tags include "theory" (for
  1021 theory begin and end), "proof" for proof commands, and "ML" for
  1022 commands involving ML code; the additional tags "visible" and
  1023 "invisible" are unused by default.  Users may give explicit tag
  1024 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1025 interpretation of tags is determined by the LaTeX job during document
  1026 preparation: see option -V of isatool usedir, or options -n and -t of
  1027 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1028 \isadroptag.
  1029 
  1030 Several document versions may be produced at the same time via isatool
  1031 usedir (the generated index.html will link all of them).  Typical
  1032 specifications include ''-V document=theory,proof,ML'' to present
  1033 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1034 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1035 these parts without any formal replacement text.  The Isabelle site
  1036 default settings produce ''document'' and ''outline'' versions as
  1037 specified above.
  1038 
  1039 * Several new antiquotations:
  1040 
  1041   @{term_type term} prints a term with its type annotated;
  1042 
  1043   @{typeof term} prints the type of a term;
  1044 
  1045   @{const const} is the same as @{term const}, but checks that the
  1046   argument is a known logical constant;
  1047 
  1048   @{term_style style term} and @{thm_style style thm} print a term or
  1049   theorem applying a "style" to it
  1050 
  1051   @{ML text}
  1052 
  1053 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1054 definitions, equations, inequations etc., 'concl' printing only the
  1055 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1056 to print the specified premise.  TermStyle.add_style provides an ML
  1057 interface for introducing further styles.  See also the "LaTeX Sugar"
  1058 document practical applications.  The ML antiquotation prints
  1059 type-checked ML expressions verbatim.
  1060 
  1061 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1062 and 'text' support optional locale specification '(in loc)', which
  1063 specifies the default context for interpreting antiquotations.  For
  1064 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1065 
  1066 * Option 'locale=NAME' of antiquotations specifies an alternative
  1067 context interpreting the subsequent argument.  For example: @{thm
  1068 [locale=lattice] inf_assoc}.
  1069 
  1070 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1071 a proof context.
  1072 
  1073 * Proper output of antiquotations for theory commands involving a
  1074 proof context (such as 'locale' or 'theorem (in loc) ...').
  1075 
  1076 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1077 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1078 
  1079 * isatool usedir: new option -C (default true) controls whether option
  1080 -D should include a copy of the original document directory; -C false
  1081 prevents unwanted effects such as copying of administrative CVS data.
  1082 
  1083 
  1084 *** Pure ***
  1085 
  1086 * Considerably improved version of 'constdefs' command.  Now performs
  1087 automatic type-inference of declared constants; additional support for
  1088 local structure declarations (cf. locales and HOL records), see also
  1089 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1090 sequential dependencies of definitions within a single 'constdefs'
  1091 section; moreover, the declared name needs to be an identifier.  If
  1092 all fails, consider to fall back on 'consts' and 'defs' separately.
  1093 
  1094 * Improved indexed syntax and implicit structures.  First of all,
  1095 indexed syntax provides a notational device for subscripted
  1096 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1097 expressions.  Secondly, in a local context with structure
  1098 declarations, number indexes \<^sub>n or the empty index (default
  1099 number 1) refer to a certain fixed variable implicitly; option
  1100 show_structs controls printing of implicit structures.  Typical
  1101 applications of these concepts involve record types and locales.
  1102 
  1103 * New command 'no_syntax' removes grammar declarations (and
  1104 translations) resulting from the given syntax specification, which is
  1105 interpreted in the same manner as for the 'syntax' command.
  1106 
  1107 * 'Advanced' translation functions (parse_translation etc.) may depend
  1108 on the signature of the theory context being presently used for
  1109 parsing/printing, see also isar-ref manual.
  1110 
  1111 * Improved 'oracle' command provides a type-safe interface to turn an
  1112 ML expression of type theory -> T -> term into a primitive rule of
  1113 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1114 is already included here); see also FOL/ex/IffExample.thy;
  1115 INCOMPATIBILITY.
  1116 
  1117 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1118 before); "cI" is no longer bound, use "c.intro" instead.
  1119 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1120 axclasses vs. locales.
  1121 
  1122 * Improved internal renaming of symbolic identifiers -- attach primes
  1123 instead of base 26 numbers.
  1124 
  1125 * New flag show_question_marks controls printing of leading question
  1126 marks in schematic variable names.
  1127 
  1128 * In schematic variable names, *any* symbol following \<^isub> or
  1129 \<^isup> is now treated as part of the base name.  For example, the
  1130 following works without printing of awkward ".0" indexes:
  1131 
  1132   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1133     by simp
  1134 
  1135 * Inner syntax includes (*(*nested*) comments*).
  1136 
  1137 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1138 annotations as "(00...)".
  1139 
  1140 * Clear separation of logical types and nonterminals, where the latter
  1141 may only occur in 'syntax' specifications or type abbreviations.
  1142 Before that distinction was only partially implemented via type class
  1143 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1144 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1145 exotic syntax specifications may require further adaption
  1146 (e.g. Cube/Cube.thy).
  1147 
  1148 * Removed obsolete type class "logic", use the top sort {} instead.
  1149 Note that non-logical types should be declared as 'nonterminals'
  1150 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1151 specifications.
  1152 
  1153 * Attributes 'induct' and 'cases': type or set names may now be
  1154 locally fixed variables as well.
  1155 
  1156 * Simplifier: can now control the depth to which conditional rewriting
  1157 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1158 Limit.
  1159 
  1160 * Simplifier: simplification procedures may now take the current
  1161 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1162 interface), which is very useful for calling the Simplifier
  1163 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1164 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1165 low-level mk_simproc no longer applies Logic.varify internally, to
  1166 allow for use in a context of fixed variables.
  1167 
  1168 * thin_tac now works even if the assumption being deleted contains !!
  1169 or ==>.  More generally, erule now works even if the major premise of
  1170 the elimination rule contains !! or ==>.
  1171 
  1172 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1173 
  1174 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1175 from Pure, which contains all common declarations already.  Both
  1176 theories are defined via plain Isabelle/Isar .thy files.
  1177 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1178 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1179 use isatool fixcpure to adapt your theory and ML sources.
  1180 
  1181 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1182 selections of theorems in named facts via index ranges.
  1183 
  1184 * 'print_theorems': in theory mode, really print the difference
  1185 wrt. the last state (works for interactive theory development only),
  1186 in proof mode print all local facts (cf. 'print_facts');
  1187 
  1188 * 'hide': option '(open)' hides only base names.
  1189 
  1190 * More efficient treatment of intermediate checkpoints in interactive
  1191 theory development.
  1192 
  1193 * Code generator is now invoked via code_module (incremental code
  1194 generation) and code_library (modular code generation, ML structures
  1195 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1196 must be quoted when used as identifiers.
  1197 
  1198 * New 'value' command for reading, evaluating and printing terms using
  1199 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1200 quoted when used as identifier.
  1201 
  1202 
  1203 *** Locales ***
  1204 
  1205 * New commands for the interpretation of locale expressions in
  1206 theories (1), locales (2) and proof contexts (3).  These generate
  1207 proof obligations from the expression specification.  After the
  1208 obligations have been discharged, theorems of the expression are added
  1209 to the theory, target locale or proof context.  The synopsis of the
  1210 commands is a follows:
  1211 
  1212   (1) interpretation expr inst
  1213   (2) interpretation target < expr
  1214   (3) interpret expr inst
  1215 
  1216 Interpretation in theories and proof contexts require a parameter
  1217 instantiation of terms from the current context.  This is applied to
  1218 specifications and theorems of the interpreted expression.
  1219 Interpretation in locales only permits parameter renaming through the
  1220 locale expression.  Interpretation is smart in that interpretations
  1221 that are active already do not occur in proof obligations, neither are
  1222 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1223 inspect active interpretations of a particular locale.  For details,
  1224 see the Isar Reference manual.  Examples can be found in
  1225 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1226 
  1227 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1228 'interpret' instead.
  1229 
  1230 * New context element 'constrains' for adding type constraints to
  1231 parameters.
  1232 
  1233 * Context expressions: renaming of parameters with syntax
  1234 redeclaration.
  1235 
  1236 * Locale declaration: 'includes' disallowed.
  1237 
  1238 * Proper static binding of attribute syntax -- i.e. types / terms /
  1239 facts mentioned as arguments are always those of the locale definition
  1240 context, independently of the context of later invocations.  Moreover,
  1241 locale operations (renaming and type / term instantiation) are applied
  1242 to attribute arguments as expected.
  1243 
  1244 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1245 actual attributes; rare situations may require Attrib.attribute to
  1246 embed those attributes into Attrib.src that lack concrete syntax.
  1247 Attribute implementations need to cooperate properly with the static
  1248 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1249 Attrib.XXX_thm etc. already do the right thing without further
  1250 intervention.  Only unusual applications -- such as "where" or "of"
  1251 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1252 on the context and the facts involved -- may have to assign parsed
  1253 values to argument tokens explicitly.
  1254 
  1255 * Changed parameter management in theorem generation for long goal
  1256 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1257 theorem statement in rare situations.
  1258 
  1259 * Locale inspection command 'print_locale' omits notes elements.  Use
  1260 'print_locale!' to have them included in the output.
  1261 
  1262 
  1263 *** Provers ***
  1264 
  1265 * Provers/hypsubst.ML: improved version of the subst method, for
  1266 single-step rewriting: it now works in bound variable contexts. New is
  1267 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1268 rewrite a different subterm than the original subst method, which is
  1269 still available as 'simplesubst'.
  1270 
  1271 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1272 and quasi orders.
  1273 
  1274 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1275 reflexive-transitive closure of relations.
  1276 
  1277 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1278 limit (previously hard-coded with a value of 20) user-definable.
  1279 
  1280 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1281 is peformed already.  Object-logics merely need to finish their
  1282 initial simpset configuration as before.  INCOMPATIBILITY.
  1283 
  1284 
  1285 *** HOL ***
  1286 
  1287 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1288 
  1289   syntax (epsilon)
  1290     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1291 
  1292 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1293 and x-symbol; use option '-m epsilon' to get it actually printed.
  1294 Moreover, the mathematically important symbolic identifier \<epsilon>
  1295 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1296 
  1297 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1298 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1299 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1300 support corresponding Isar calculations.
  1301 
  1302 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1303 instead of ":".
  1304 
  1305 * theory SetInterval: changed the syntax for open intervals:
  1306 
  1307   Old       New
  1308   {..n(}    {..<n}
  1309   {)n..}    {n<..}
  1310   {m..n(}   {m..<n}
  1311   {)m..n}   {m<..n}
  1312   {)m..n(}  {m<..<n}
  1313 
  1314 The old syntax is still supported but will disappear in the next
  1315 release.  For conversion use the following Emacs search and replace
  1316 patterns (these are not perfect but work quite well):
  1317 
  1318   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1319   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1320 
  1321 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1322 equalities in commutative rings; method 'algebra' provides a generic
  1323 interface.
  1324 
  1325 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1326 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1327 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1328 be a tuple pattern.
  1329 
  1330 Some new syntax forms are available:
  1331 
  1332   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1333   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1334   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1335   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1336 
  1337 The latter form "\<Sum>x < k. e" used to be based on a separate
  1338 function "Summation", which has been discontinued.
  1339 
  1340 * theory Finite_Set: in structured induction proofs, the insert case
  1341 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1342 (insert F x)'.
  1343 
  1344 * The 'refute' command has been extended to support a much larger
  1345 fragment of HOL, including axiomatic type classes, constdefs and
  1346 typedefs, inductive datatypes and recursion.
  1347 
  1348 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1349 Requires zChaff with proof generation to be installed.  See
  1350 HOL/ex/SAT_Examples.thy for examples.
  1351 
  1352 * Datatype induction via method 'induct' now preserves the name of the
  1353 induction variable. For example, when proving P(xs::'a list) by
  1354 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1355 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1356 in unstructured proof scripts.
  1357 
  1358 * Reworked implementation of records.  Improved scalability for
  1359 records with many fields, avoiding performance problems for type
  1360 inference. Records are no longer composed of nested field types, but
  1361 of nested extension types. Therefore the record type only grows linear
  1362 in the number of extensions and not in the number of fields.  The
  1363 top-level (users) view on records is preserved.  Potential
  1364 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1365 old record representation. The type generated for a record is called
  1366 <record_name>_ext_type.
  1367 
  1368 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1369 proofs triggered by a record definition or a simproc (if
  1370 quick_and_dirty is enabled).  Definitions of large records can take
  1371 quite long.
  1372 
  1373 New simproc record_upd_simproc for simplification of multiple record
  1374 updates enabled by default.  Moreover, trivial updates are also
  1375 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1376 occasionally, since simplification is more powerful by default.
  1377 
  1378 * typedef: proper support for polymorphic sets, which contain extra
  1379 type-variables in the term.
  1380 
  1381 * Simplifier: automatically reasons about transitivity chains
  1382 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1383 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1384 old proofs break occasionally as simplification may now solve more
  1385 goals than previously.
  1386 
  1387 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1388 present.  Works for all partial orders (class "order"), in particular
  1389 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1390 just like y <= x.
  1391 
  1392 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1393 bound variable or a constant then the let is unfolded.  Otherwise
  1394 first a is simplified to b, and then f b is simplified to g. If
  1395 possible we abstract b from g arriving at "let x = b in h x",
  1396 otherwise we unfold the let and arrive at g.  The simproc can be
  1397 enabled/disabled by the reference use_let_simproc.  Potential
  1398 INCOMPATIBILITY since simplification is more powerful by default.
  1399 
  1400 * Classical reasoning: the meson method now accepts theorems as arguments.
  1401 
  1402 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1403 jobs to provide advice on the provability of subgoals.
  1404 
  1405 * Theory OrderedGroup and Ring_and_Field: various additions and
  1406 improvements to faciliate calculations involving equalities and
  1407 inequalities.
  1408 
  1409 The following theorems have been eliminated or modified
  1410 (INCOMPATIBILITY):
  1411 
  1412   abs_eq             now named abs_of_nonneg
  1413   abs_of_ge_0        now named abs_of_nonneg
  1414   abs_minus_eq       now named abs_of_nonpos
  1415   imp_abs_id         now named abs_of_nonneg
  1416   imp_abs_neg_id     now named abs_of_nonpos
  1417   mult_pos           now named mult_pos_pos
  1418   mult_pos_le        now named mult_nonneg_nonneg
  1419   mult_pos_neg_le    now named mult_nonneg_nonpos
  1420   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1421   mult_neg           now named mult_neg_neg
  1422   mult_neg_le        now named mult_nonpos_nonpos
  1423 
  1424 * Theory Parity: added rules for simplifying exponents.
  1425 
  1426 * Theory List:
  1427 
  1428 The following theorems have been eliminated or modified
  1429 (INCOMPATIBILITY):
  1430 
  1431   list_all_Nil       now named list_all.simps(1)
  1432   list_all_Cons      now named list_all.simps(2)
  1433   list_all_conv      now named list_all_iff
  1434   set_mem_eq         now named mem_iff
  1435 
  1436 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1437 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1438 
  1439 
  1440 *** HOL-Complex ***
  1441 
  1442 * Theory RealDef: better support for embedding natural numbers and
  1443 integers in the reals.
  1444 
  1445 The following theorems have been eliminated or modified
  1446 (INCOMPATIBILITY):
  1447 
  1448   exp_ge_add_one_self  now requires no hypotheses
  1449   real_of_int_add      reversed direction of equality (use [symmetric])
  1450   real_of_int_minus    reversed direction of equality (use [symmetric])
  1451   real_of_int_diff     reversed direction of equality (use [symmetric])
  1452   real_of_int_mult     reversed direction of equality (use [symmetric])
  1453 
  1454 * Theory RComplete: expanded support for floor and ceiling functions.
  1455 
  1456 * Theory Ln is new, with properties of the natural logarithm
  1457 
  1458 * Hyperreal: There is a new type constructor "star" for making
  1459 nonstandard types.  The old type names are now type synonyms:
  1460 
  1461   hypreal = real star
  1462   hypnat = nat star
  1463   hcomplex = complex star
  1464 
  1465 * Hyperreal: Many groups of similarly-defined constants have been
  1466 replaced by polymorphic versions (INCOMPATIBILITY):
  1467 
  1468   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1469 
  1470   starset      <-- starsetNat, starsetC
  1471   *s*          <-- *sNat*, *sc*
  1472   starset_n    <-- starsetNat_n, starsetC_n
  1473   *sn*         <-- *sNatn*, *scn*
  1474   InternalSets <-- InternalNatSets, InternalCSets
  1475 
  1476   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1477   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1478   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1479   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1480   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1481 
  1482 * Hyperreal: Many type-specific theorems have been removed in favor of
  1483 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1484 
  1485   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1486   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1487   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1488   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1489   right_minus <-- hypreal_add_minus
  1490   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1491   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1492   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1493   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1494   mult_1_right <-- hcomplex_mult_one_right
  1495   mult_zero_left <-- hcomplex_mult_zero_left
  1496   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1497   right_distrib <-- hypnat_add_mult_distrib2
  1498   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1499   right_inverse <-- hypreal_mult_inverse
  1500   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1501   order_refl <-- {hypreal,hypnat}_le_refl
  1502   order_trans <-- {hypreal,hypnat}_le_trans
  1503   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1504   order_less_le <-- {hypreal,hypnat}_less_le
  1505   linorder_linear <-- {hypreal,hypnat}_le_linear
  1506   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1507   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1508   add_nonneg_nonneg <-- hypreal_le_add_order
  1509 
  1510 * Hyperreal: Separate theorems having to do with type-specific
  1511 versions of constants have been merged into theorems that apply to the
  1512 new polymorphic constants (INCOMPATIBILITY):
  1513 
  1514   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1515   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1516   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1517   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1518   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1519   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1520   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1521   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1522   STAR_diff <-- {STAR,STARC}_diff
  1523   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1524     STARC_hcomplex_of_complex}_image_subset
  1525   starset_n_Un <-- starset{Nat,C}_n_Un
  1526   starset_n_Int <-- starset{Nat,C}_n_Int
  1527   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1528   starset_n_diff <-- starset{Nat,C}_n_diff
  1529   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1530   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1531   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1532   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1533   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1534   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1535   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1536   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1537   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1538   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1539   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1540   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1541   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1542   starfun_diff <-- starfun{C,RC,CR}_diff
  1543   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1544   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1545   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1546   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1547   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1548   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1549   starfun_Id <-- starfunC_Id
  1550   starfun_approx <-- starfun{Nat,CR}_approx
  1551   starfun_capprox <-- starfun{C,RC}_capprox
  1552   starfun_abs <-- starfunNat_rabs
  1553   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1554   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1555   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1556   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1557   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1558   starfun_add_approx <-- starfunCR_add_approx
  1559   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1560   starfun_divide <-- starfun{C,CR,RC}_divide
  1561   starfun_n <-- starfun{Nat,C}_n
  1562   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1563   starfun_n_add <-- starfun{Nat,C}_n_add
  1564   starfun_n_add_minus <-- starfunNat_n_add_minus
  1565   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1566   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1567   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1568 
  1569   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1570   star_n_minus <-- {hypreal,hcomplex}_minus
  1571   star_n_diff <-- {hypreal,hcomplex}_diff
  1572   star_n_mult <-- {hypreal,hcomplex}_mult
  1573   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1574   star_n_le <-- {hypreal,hypnat}_le
  1575   star_n_less <-- {hypreal,hypnat}_less
  1576   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1577   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1578   star_n_abs <-- hypreal_hrabs
  1579   star_n_divide <-- hcomplex_divide
  1580 
  1581   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1582   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1583   star_of_diff <-- hypreal_of_real_diff
  1584   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1585   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1586   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1587   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1588   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1589   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1590   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1591   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1592   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1593   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1594   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1595   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1596   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1597   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1598   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1599   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1600   star_of_power <-- hypreal_of_real_power
  1601   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1602 
  1603 * Hyperreal: new method "transfer" that implements the transfer
  1604 principle of nonstandard analysis. With a subgoal that mentions
  1605 nonstandard types like "'a star", the command "apply transfer"
  1606 replaces it with an equivalent one that mentions only standard types.
  1607 To be successful, all free variables must have standard types; non-
  1608 standard variables must have explicit universal quantifiers.
  1609 
  1610 * Hyperreal: A theory of Taylor series.
  1611 
  1612 
  1613 *** HOLCF ***
  1614 
  1615 * Discontinued special version of 'constdefs' (which used to support
  1616 continuous functions) in favor of the general Pure one with full
  1617 type-inference.
  1618 
  1619 * New simplification procedure for solving continuity conditions; it
  1620 is much faster on terms with many nested lambda abstractions (cubic
  1621 instead of exponential time).
  1622 
  1623 * New syntax for domain package: selector names are now optional.
  1624 Parentheses should be omitted unless argument is lazy, for example:
  1625 
  1626   domain 'a stream = cons "'a" (lazy "'a stream")
  1627 
  1628 * New command 'fixrec' for defining recursive functions with pattern
  1629 matching; defining multiple functions with mutual recursion is also
  1630 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1631 sinr, or any data constructor defined by the domain package. The given
  1632 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1633 syntax and examples.
  1634 
  1635 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1636 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1637 but the proof obligation additionally includes an admissibility
  1638 requirement. The packages generate instances of class cpo or pcpo,
  1639 with continuity and strictness theorems for Rep and Abs.
  1640 
  1641 * HOLCF: Many theorems have been renamed according to a more standard naming
  1642 scheme (INCOMPATIBILITY):
  1643 
  1644   foo_inject:  "foo$x = foo$y ==> x = y"
  1645   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1646   foo_less:    "(foo$x << foo$y) = (x << y)"
  1647   foo_strict:  "foo$UU = UU"
  1648   foo_defined: "... ==> foo$x ~= UU"
  1649   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1650 
  1651 
  1652 *** ZF ***
  1653 
  1654 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1655 including the First Isomorphism Theorem (on quotienting by the kernel
  1656 of a homomorphism).
  1657 
  1658 * ZF/Simplifier: install second copy of type solver that actually
  1659 makes use of TC rules declared to Isar proof contexts (or locales);
  1660 the old version is still required for ML proof scripts.
  1661 
  1662 
  1663 *** Cube ***
  1664 
  1665 * Converted to Isar theory format; use locales instead of axiomatic
  1666 theories.
  1667 
  1668 
  1669 *** ML ***
  1670 
  1671 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1672 for ||>, ||>>, |>>,
  1673 
  1674 * Pure/library.ML no longer defines its own option datatype, but uses
  1675 that of the SML basis, which has constructors NONE and SOME instead of
  1676 None and Some, as well as exception Option.Option instead of OPTION.
  1677 The functions the, if_none, is_some, is_none have been adapted
  1678 accordingly, while Option.map replaces apsome.
  1679 
  1680 * Pure/library.ML: the exception LIST has been given up in favour of
  1681 the standard exceptions Empty and Subscript, as well as
  1682 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1683 superceded by the standard hd and tl functions etc.
  1684 
  1685 A number of basic list functions are no longer exported to the ML
  1686 toplevel, as they are variants of predefined functions.  The following
  1687 suggests how one can translate existing code:
  1688 
  1689     rev_append xs ys = List.revAppend (xs, ys)
  1690     nth_elem (i, xs) = List.nth (xs, i)
  1691     last_elem xs = List.last xs
  1692     flat xss = List.concat xss
  1693     seq fs = List.app fs
  1694     partition P xs = List.partition P xs
  1695     mapfilter f xs = List.mapPartial f xs
  1696 
  1697 * Pure/library.ML: several combinators for linear functional
  1698 transformations, notably reverse application and composition:
  1699 
  1700   x |> f                f #> g
  1701   (x, y) |-> f          f #-> g
  1702 
  1703 * Pure/library.ML: introduced/changed precedence of infix operators:
  1704 
  1705   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1706   infix 2 ?;
  1707   infix 3 o oo ooo oooo;
  1708   infix 4 ~~ upto downto;
  1709 
  1710 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1711 infix operators.
  1712 
  1713 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1714 fold_map support linear functional transformations and nesting.  For
  1715 example:
  1716 
  1717   fold f [x1, ..., xN] y =
  1718     y |> f x1 |> ... |> f xN
  1719 
  1720   (fold o fold) f [xs1, ..., xsN] y =
  1721     y |> fold f xs1 |> ... |> fold f xsN
  1722 
  1723   fold f [x1, ..., xN] =
  1724     f x1 #> ... #> f xN
  1725 
  1726   (fold o fold) f [xs1, ..., xsN] =
  1727     fold f xs1 #> ... #> fold f xsN
  1728 
  1729 * Pure/library.ML: the following selectors on type 'a option are
  1730 available:
  1731 
  1732   the:               'a option -> 'a  (*partial*)
  1733   these:             'a option -> 'a  where 'a = 'b list
  1734   the_default: 'a -> 'a option -> 'a
  1735   the_list:          'a option -> 'a list
  1736 
  1737 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1738 basic operations for association lists, following natural argument
  1739 order; moreover the explicit equality predicate passed here avoids
  1740 potentially expensive polymorphic runtime equality checks.
  1741 The old functions may be expressed as follows:
  1742 
  1743   assoc = uncurry (AList.lookup (op =))
  1744   assocs = these oo AList.lookup (op =)
  1745   overwrite = uncurry (AList.update (op =)) o swap
  1746 
  1747 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1748 
  1749   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1750   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1751 
  1752 replacing make_keylist and keyfilter (occassionally used)
  1753 Naive rewrites:
  1754 
  1755   make_keylist = AList.make
  1756   keyfilter = AList.find (op =)
  1757 
  1758 * eq_fst and eq_snd now take explicit equality parameter, thus
  1759   avoiding eqtypes. Naive rewrites:
  1760 
  1761     eq_fst = eq_fst (op =)
  1762     eq_snd = eq_snd (op =)
  1763 
  1764 * Removed deprecated apl and apr (rarely used).
  1765   Naive rewrites:
  1766 
  1767     apl (n, op) =>>= curry op n
  1768     apr (op, m) =>>= fn n => op (n, m)
  1769 
  1770 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1771 provides a reasonably efficient light-weight implementation of sets as
  1772 lists.
  1773 
  1774 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1775 few new operations; existing lookup and update are now curried to
  1776 follow natural argument order (for use with fold etc.);
  1777 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1778 
  1779 * Pure/General: output via the Isabelle channels of
  1780 writeln/warning/error etc. is now passed through Output.output, with a
  1781 hook for arbitrary transformations depending on the print_mode
  1782 (cf. Output.add_mode -- the first active mode that provides a output
  1783 function wins).  Already formatted output may be embedded into further
  1784 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1785 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1786 accommodate easy composition of diagnostic messages etc.  Programmers
  1787 rarely need to care about Output.output or Output.raw at all, with
  1788 some notable exceptions: Output.output is required when bypassing the
  1789 standard channels (writeln etc.), or in token translations to produce
  1790 properly formatted results; Output.raw is required when capturing
  1791 already output material that will eventually be presented to the user
  1792 a second time.  For the default print mode, both Output.output and
  1793 Output.raw have no effect.
  1794 
  1795 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1796 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1797 cumulative results are displayed at the end of a batch session.
  1798 
  1799 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1800 replaced by File.platform_path and File.shell_path (with appropriate
  1801 hooks).  This provides a clean interface for unusual systems where the
  1802 internal and external process view of file names are different.
  1803 
  1804 * Pure: more efficient orders for basic syntactic entities: added
  1805 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1806 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1807 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1808 orders now -- potential INCOMPATIBILITY for code that depends on a
  1809 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1810 Library.sort_strings on result).
  1811 
  1812 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1813 fold_types traverse types/terms from left to right, observing natural
  1814 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1815 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1816 
  1817 * Pure: name spaces have been refined, with significant changes of the
  1818 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1819 to extern(_table).  The plain name entry path is superceded by a
  1820 general 'naming' context, which also includes the 'policy' to produce
  1821 a fully qualified name and external accesses of a fully qualified
  1822 name; NameSpace.extend is superceded by context dependent
  1823 Sign.declare_name.  Several theory and proof context operations modify
  1824 the naming context.  Especially note Theory.restore_naming and
  1825 ProofContext.restore_naming to get back to a sane state; note that
  1826 Theory.add_path is no longer sufficient to recover from
  1827 Theory.absolute_path in particular.
  1828 
  1829 * Pure: new flags short_names (default false) and unique_names
  1830 (default true) for controlling output of qualified names.  If
  1831 short_names is set, names are printed unqualified.  If unique_names is
  1832 reset, the name prefix is reduced to the minimum required to achieve
  1833 the original result when interning again, even if there is an overlap
  1834 with earlier declarations.
  1835 
  1836 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1837 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1838 (useful for printing error messages).  INCOMPATIBILITY.
  1839 
  1840 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1841 Theory.theory are now identified, referring to the universal
  1842 Context.theory (see Pure/context.ML).  Actual signature and theory
  1843 content is managed as theory data.  The old code and interfaces were
  1844 spread over many files and structures; the new arrangement introduces
  1845 considerable INCOMPATIBILITY to gain more clarity:
  1846 
  1847   Context -- theory management operations (name, identity, inclusion,
  1848     parents, ancestors, merge, etc.), plus generic theory data;
  1849 
  1850   Sign -- logical signature and syntax operations (declaring consts,
  1851     types, etc.), plus certify/read for common entities;
  1852 
  1853   Theory -- logical theory operations (stating axioms, definitions,
  1854     oracles), plus a copy of logical signature operations (consts,
  1855     types, etc.); also a few basic management operations (Theory.copy,
  1856     Theory.merge, etc.)
  1857 
  1858 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1859 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1860 for convenience -- they merely return the theory.
  1861 
  1862 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1863 
  1864 * Pure: the Isar proof context type is already defined early in Pure
  1865 as Context.proof (note that ProofContext.context and Proof.context are
  1866 aliases, where the latter is the preferred name).  This enables other
  1867 Isabelle components to refer to that type even before Isar is present.
  1868 
  1869 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1870 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1871 any of these kinds.  For example, Sign.intern typeK is now
  1872 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1873 Theory.hide_types.  Also note that former
  1874 Theory.hide_classes/types/consts are now
  1875 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1876 internalize their arguments!  INCOMPATIBILITY.
  1877 
  1878 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1879 datatype thmref (with constructors Name and NameSelection) instead of
  1880 plain string -- INCOMPATIBILITY;
  1881 
  1882 * Pure: cases produced by proof methods specify options, where NONE
  1883 means to remove case bindings -- INCOMPATIBILITY in
  1884 (RAW_)METHOD_CASES.
  1885 
  1886 * Pure: the following operations retrieve axioms or theorems from a
  1887 theory node or theory hierarchy, respectively:
  1888 
  1889   Theory.axioms_of: theory -> (string * term) list
  1890   Theory.all_axioms_of: theory -> (string * term) list
  1891   PureThy.thms_of: theory -> (string * thm) list
  1892   PureThy.all_thms_of: theory -> (string * thm) list
  1893 
  1894 * Pure: print_tac now outputs the goal through the trace channel.
  1895 
  1896 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1897 Reference Toplevel.debug (default false) controls detailed printing
  1898 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1899 controls execution profiling -- set to 1 for time and 2 for space
  1900 (both increase the runtime).
  1901 
  1902 * Isar session: The initial use of ROOT.ML is now always timed,
  1903 i.e. the log will show the actual process times, in contrast to the
  1904 elapsed wall-clock time that the outer shell wrapper produces.
  1905 
  1906 * Simplifier: improved handling of bound variables (nameless
  1907 representation, avoid allocating new strings).  Simprocs that invoke
  1908 the Simplifier recursively should use Simplifier.inherit_bounds to
  1909 avoid local name clashes.  Failure to do so produces warnings
  1910 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1911 for further details.
  1912 
  1913 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1914 bindings for all theorems stored within a given theory; this may help
  1915 in porting non-Isar theories to Isar ones, while keeping ML proof
  1916 scripts for the time being.
  1917 
  1918 * ML operator HTML.with_charset specifies the charset begin used for
  1919 generated HTML files.  For example:
  1920 
  1921   HTML.with_charset "utf-8" use_thy "Hebrew";
  1922   HTML.with_charset "utf-8" use_thy "Chinese";
  1923 
  1924 
  1925 *** System ***
  1926 
  1927 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1928 isabelle, isatool etc.).
  1929 
  1930 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1931 isatool doc, isatool mkdir, display_drafts etc.).
  1932 
  1933 * isatool usedir: option -f allows specification of the ML file to be
  1934 used by Isabelle; default is ROOT.ML.
  1935 
  1936 * New isatool version outputs the version identifier of the Isabelle
  1937 distribution being used.
  1938 
  1939 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1940 (containing Boolean satisfiability problems) into Isabelle/HOL
  1941 theories.
  1942 
  1943 
  1944 
  1945 New in Isabelle2004 (April 2004)
  1946 --------------------------------
  1947 
  1948 *** General ***
  1949 
  1950 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1951   Replaces linorder.ML.
  1952 
  1953 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1954   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1955   (\<a>...\<z>), are now considered normal letters, and can therefore
  1956   be used anywhere where an ASCII letter (a...zA...Z) has until
  1957   now. COMPATIBILITY: This obviously changes the parsing of some
  1958   terms, especially where a symbol has been used as a binder, say
  1959   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1960   as an identifier.  Fix it by inserting a space around former
  1961   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1962   existing theory and ML files.
  1963 
  1964 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1965 
  1966 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1967   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1968   a normal (but invisible) letter. For multiple letter subscripts repeat
  1969   \<^isub> like this: x\<^isub>1\<^isub>2.
  1970 
  1971 * Pure: There are now sub-/superscripts that can span more than one
  1972   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1973   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1974   superscript. The new control characters are not identifier parts.
  1975 
  1976 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1977   content of "..." to the latex file instead of \isacntrl... . The "..."
  1978   may consist of any printable characters excluding the end bracket >.
  1979 
  1980 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1981   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1982   declare constants "final", which prevents their being given a definition
  1983   later.  It is useful for constants whose behaviour is fixed axiomatically
  1984   rather than definitionally, such as the meta-logic connectives.
  1985 
  1986 * Pure: 'instance' now handles general arities with general sorts
  1987   (i.e. intersections of classes),
  1988 
  1989 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1990   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1991   It can be changed to alter the colors/layout of generated pages.
  1992 
  1993 
  1994 *** Isar ***
  1995 
  1996 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1997   cut_tac, subgoal_tac and thin_tac:
  1998   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1999     locales are no longer forced to write Isar proof scripts.
  2000     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2001     emulations.
  2002   - INCOMPATIBILITY: names of variables to be instantiated may no
  2003     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2004     This is consistent with the instantiation attribute "where".
  2005 
  2006 * Attributes "where" and "of":
  2007   - Now take type variables of instantiated theorem into account when reading
  2008     the instantiation string.  This fixes a bug that caused instantiated
  2009     theorems to have too special types in some circumstances.
  2010   - "where" permits explicit instantiations of type variables.
  2011 
  2012 * Calculation commands "moreover" and "also" no longer interfere with
  2013   current facts ("this"), admitting arbitrary combinations with "then"
  2014   and derived forms.
  2015 
  2016 * Locales:
  2017   - Goal statements involving the context element "includes" no longer
  2018     generate theorems with internal delta predicates (those ending on
  2019     "_axioms") in the premise.
  2020     Resolve particular premise with <locale>.intro to obtain old form.
  2021   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2022     specification and "includes" elements in goal statement.
  2023   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2024     [intro?] and [elim?] (respectively) by default.
  2025   - Experimental command for instantiation of locales in proof contexts:
  2026         instantiate <label>[<attrs>]: <loc>
  2027     Instantiates locale <loc> and adds all its theorems to the current context
  2028     taking into account their attributes.  Label and attrs are optional
  2029     modifiers, like in theorem declarations.  If present, names of
  2030     instantiated theorems are qualified with <label>, and the attributes
  2031     <attrs> are applied after any attributes these theorems might have already.
  2032       If the locale has assumptions, a chained fact of the form
  2033     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2034     are derived.  The command does not support old-style locales declared
  2035     with "locale (open)".
  2036       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2037 
  2038 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2039   (Isar) contexts.
  2040 
  2041 
  2042 *** HOL ***
  2043 
  2044 * Proof import: new image HOL4 contains the imported library from
  2045   the HOL4 system with about 2500 theorems. It is imported by
  2046   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2047   can be used like any other Isabelle image.  See
  2048   HOL/Import/HOL/README for more information.
  2049 
  2050 * Simplifier:
  2051   - Much improved handling of linear and partial orders.
  2052     Reasoners for linear and partial orders are set up for type classes
  2053     "linorder" and "order" respectively, and are added to the default simpset
  2054     as solvers.  This means that the simplifier can build transitivity chains
  2055     to solve goals from the assumptions.
  2056   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2057     of blast or auto after simplification become unnecessary because the goal
  2058     is solved by simplification already.
  2059 
  2060 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2061     all proved in axiomatic type classes for semirings, rings and fields.
  2062 
  2063 * Numerics:
  2064   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2065     now formalized using the Ring_and_Field theory mentioned above.
  2066   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2067     than before, because now they are set up once in a generic manner.
  2068   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2069     Look for the general versions in Ring_and_Field (and Power if they concern
  2070     exponentiation).
  2071 
  2072 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2073 
  2074 * Records:
  2075   - Record types are now by default printed with their type abbreviation
  2076     instead of the list of all field types. This can be configured via
  2077     the reference "print_record_type_abbr".
  2078   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2079     (not enabled by default).
  2080   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2081     EX x. x = sel r to True (not enabled by default).
  2082   - Tactic "record_split_simp_tac" to split and simplify records added.
  2083 
  2084 * 'specification' command added, allowing for definition by
  2085   specification.  There is also an 'ax_specification' command that
  2086   introduces the new constants axiomatically.
  2087 
  2088 * arith(_tac) is now able to generate counterexamples for reals as well.
  2089 
  2090 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2091 
  2092 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2093   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2094 
  2095 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2096   matrix theory to linear programming.
  2097 
  2098 * Unions and Intersections:
  2099   The latex output syntax of UN and INT has been changed
  2100   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2101   i.e. the index formulae has become a subscript.
  2102   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2103 
  2104 * Unions and Intersections over Intervals:
  2105   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2106   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2107   like in normal math, and corresponding versions for < and for intersection.
  2108 
  2109 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2110   lexicographic dictonary ordering has been added as "lexord".
  2111 
  2112 * ML: the legacy theory structures Int and List have been removed. They had
  2113   conflicted with ML Basis Library structures having the same names.
  2114 
  2115 * 'refute' command added to search for (finite) countermodels.  Only works
  2116   for a fragment of HOL.  The installation of an external SAT solver is
  2117   highly recommended.  See "HOL/Refute.thy" for details.
  2118 
  2119 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2120   formulae under an assignment of free variables to random values.
  2121   In contrast to 'refute', it can deal with inductive datatypes,
  2122   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2123   for examples.
  2124 
  2125 
  2126 *** HOLCF ***
  2127 
  2128 * Streams now come with concatenation and are part of the HOLCF image
  2129 
  2130 
  2131 
  2132 New in Isabelle2003 (May 2003)
  2133 ------------------------------
  2134 
  2135 *** General ***
  2136 
  2137 * Provers/simplifier:
  2138 
  2139   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2140     Assumptions are now subject to complete mutual simplification,
  2141     not just from left to right. The simplifier now preserves
  2142     the order of assumptions.
  2143 
  2144     Potential INCOMPATIBILITY:
  2145 
  2146     -- simp sometimes diverges where the old version did
  2147        not, e.g. invoking simp on the goal
  2148 
  2149         [| P (f x); y = x; f x = f y |] ==> Q
  2150 
  2151        now gives rise to the infinite reduction sequence
  2152 
  2153         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2154 
  2155        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2156        kind of problem.
  2157 
  2158     -- Tactics combining classical reasoner and simplification (such as auto)
  2159        are also affected by this change, because many of them rely on
  2160        simp. They may sometimes diverge as well or yield a different numbers
  2161        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2162        in case of problems. Sometimes subsequent calls to the classical
  2163        reasoner will fail because a preceeding call to the simplifier too
  2164        eagerly simplified the goal, e.g. deleted redundant premises.
  2165 
  2166   - The simplifier trace now shows the names of the applied rewrite rules
  2167 
  2168   - You can limit the number of recursive invocations of the simplifier
  2169     during conditional rewriting (where the simplifie tries to solve the
  2170     conditions before applying the rewrite rule):
  2171     ML "simp_depth_limit := n"
  2172     where n is an integer. Thus you can force termination where previously
  2173     the simplifier would diverge.
  2174 
  2175   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2176 
  2177   - No longer aborts on failed congruence proof.  Instead, the
  2178     congruence is ignored.
  2179 
  2180 * Pure: New generic framework for extracting programs from constructive
  2181   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2182   as HOL/Extraction for some case studies.
  2183 
  2184 * Pure: The main goal of the proof state is no longer shown by default, only
  2185 the subgoals. This behaviour is controlled by a new flag.
  2186    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2187 (ML: Proof.show_main_goal).
  2188 
  2189 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2190 rules whose conclusion matches subgoal 1:
  2191       PG menu: Isabelle/Isar -> Show me -> matching rules
  2192 The rules are ordered by how closely they match the subgoal.
  2193 In particular, rules that solve a subgoal outright are displayed first
  2194 (or rather last, the way they are printed).
  2195 (ML: ProofGeneral.print_intros())
  2196 
  2197 * Pure: New flag trace_unify_fail causes unification to print
  2198 diagnostic information (PG: in trace buffer) when it fails. This is
  2199 useful for figuring out why single step proofs like rule, erule or
  2200 assumption failed.
  2201 
  2202 * Pure: Locale specifications now produce predicate definitions
  2203 according to the body of text (covering assumptions modulo local
  2204 definitions); predicate "loc_axioms" covers newly introduced text,
  2205 while "loc" is cumulative wrt. all included locale expressions; the
  2206 latter view is presented only on export into the global theory
  2207 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2208 on the old view without predicates;
  2209 
  2210 * Pure: predefined locales "var" and "struct" are useful for sharing
  2211 parameters (as in CASL, for example); just specify something like
  2212 ``var x + var y + struct M'' as import;
  2213 
  2214 * Pure: improved thms_containing: proper indexing of facts instead of
  2215 raw theorems; check validity of results wrt. current name space;
  2216 include local facts of proof configuration (also covers active
  2217 locales), cover fixed variables in index; may use "_" in term
  2218 specification; an optional limit for the number of printed facts may
  2219 be given (the default is 40);
  2220 
  2221 * Pure: disallow duplicate fact bindings within new-style theory files
  2222 (batch-mode only);
  2223 
  2224 * Provers: improved induct method: assumptions introduced by case
  2225 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2226 the goal statement); "foo" still refers to all facts collectively;
  2227 
  2228 * Provers: the function blast.overloaded has been removed: all constants
  2229 are regarded as potentially overloaded, which improves robustness in exchange
  2230 for slight decrease in efficiency;
  2231 
  2232 * Provers/linorder: New generic prover for transitivity reasoning over
  2233 linear orders.  Note: this prover is not efficient!
  2234 
  2235 * Isar: preview of problems to finish 'show' now produce an error
  2236 rather than just a warning (in interactive mode);
  2237 
  2238 
  2239 *** HOL ***
  2240 
  2241 * arith(_tac)
  2242 
  2243  - Produces a counter example if it cannot prove a goal.
  2244    Note that the counter example may be spurious if the goal is not a formula
  2245    of quantifier-free linear arithmetic.
  2246    In ProofGeneral the counter example appears in the trace buffer.
  2247 
  2248  - Knows about div k and mod k where k is a numeral of type nat or int.
  2249 
  2250  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2251    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2252    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2253 
  2254 * simp's arithmetic capabilities have been enhanced a bit: it now
  2255 takes ~= in premises into account (by performing a case split);
  2256 
  2257 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2258 are distributed over a sum of terms;
  2259 
  2260 * New tactic "trans_tac" and method "trans" instantiate
  2261 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2262 "<=", "<" and "=").
  2263 
  2264 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2265 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2266 
  2267 * 'typedef' command has new option "open" to suppress the set
  2268 definition;
  2269 
  2270 * functions Min and Max on finite sets have been introduced (theory
  2271 Finite_Set);
  2272 
  2273 * attribute [symmetric] now works for relations as well; it turns
  2274 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2275 
  2276 * induct over a !!-quantified statement (say !!x1..xn):
  2277   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2278 
  2279 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2280 %x. None. Warning: empty_def now refers to the previously hidden definition
  2281 of the empty set.
  2282 
  2283 * Algebra: formalization of classical algebra.  Intended as base for
  2284 any algebraic development in Isabelle.  Currently covers group theory
  2285 (up to Sylow's theorem) and ring theory (Universal Property of
  2286 Univariate Polynomials).  Contributions welcome;
  2287 
  2288 * GroupTheory: deleted, since its material has been moved to Algebra;
  2289 
  2290 * Complex: new directory of the complex numbers with numeric constants,
  2291 nonstandard complex numbers, and some complex analysis, standard and
  2292 nonstandard (Jacques Fleuriot);
  2293 
  2294 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2295 
  2296 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2297 Fleuriot);
  2298 
  2299 * Real/HahnBanach: updated and adapted to locales;
  2300 
  2301 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2302 Gray and Kramer);
  2303 
  2304 * UNITY: added the Meier-Sanders theory of progress sets;
  2305 
  2306 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2307 as abstract algorithms, instantiated to the JVM;
  2308 
  2309 * Bali: Java source language formalization. Type system, operational
  2310 semantics, axiomatic semantics. Supported language features:
  2311 classes, interfaces, objects,virtual methods, static methods,
  2312 static/instance fields, arrays, access modifiers, definite
  2313 assignment, exceptions.
  2314 
  2315 
  2316 *** ZF ***
  2317 
  2318 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2319 universe, etc.);
  2320 
  2321 * Main ZF: virtually all theories converted to new-style format;
  2322 
  2323 
  2324 *** ML ***
  2325 
  2326 * Pure: Tactic.prove provides sane interface for internal proofs;
  2327 omits the infamous "standard" operation, so this is more appropriate
  2328 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2329 
  2330 * Pure: improved error reporting of simprocs;
  2331 
  2332 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2333 up simprocs;
  2334 
  2335 
  2336 *** Document preparation ***
  2337 
  2338 * uses \par instead of \\ for line breaks in theory text. This may
  2339 shift some page breaks in large documents. To get the old behaviour
  2340 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2341 
  2342 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2343 other packages
  2344 
  2345 * \<euro> now needs package babel/greek instead of marvosym (which
  2346 broke \Rightarrow)
  2347 
  2348 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2349 textcomp package)
  2350 
  2351 
  2352 
  2353 New in Isabelle2002 (March 2002)
  2354 --------------------------------
  2355 
  2356 *** Document preparation ***
  2357 
  2358 * greatly simplified document preparation setup, including more
  2359 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2360 instructive isatool mkdir; users should basically be able to get
  2361 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2362 users may run a separate document processing stage manually like this:
  2363 "isatool usedir -D output HOL Test && isatool document Test/output";
  2364 
  2365 * theory dependency graph may now be incorporated into documents;
  2366 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2367 with \includegraphics of LaTeX;
  2368 
  2369 * proper spacing of consecutive markup elements, especially text
  2370 blocks after section headings;
  2371 
  2372 * support bold style (for single symbols only), input syntax is like
  2373 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2374 
  2375 * \<bullet> is now output as bold \cdot by default, which looks much
  2376 better in printed text;
  2377 
  2378 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2379 note that these symbols are currently unavailable in Proof General /
  2380 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2381 
  2382 * isatool latex no longer depends on changed TEXINPUTS, instead
  2383 isatool document copies the Isabelle style files to the target
  2384 location;
  2385 
  2386 
  2387 *** Isar ***
  2388 
  2389 * Pure/Provers: improved proof by cases and induction;
  2390   - 'case' command admits impromptu naming of parameters (such as
  2391     "case (Suc n)");
  2392   - 'induct' method divinates rule instantiation from the inductive
  2393     claim; no longer requires excessive ?P bindings for proper
  2394     instantiation of cases;
  2395   - 'induct' method properly enumerates all possibilities of set/type
  2396     rules; as a consequence facts may be also passed through *type*
  2397     rules without further ado;
  2398   - 'induct' method now derives symbolic cases from the *rulified*
  2399     rule (before it used to rulify cases stemming from the internal
  2400     atomized version); this means that the context of a non-atomic
  2401     statement becomes is included in the hypothesis, avoiding the
  2402     slightly cumbersome show "PROP ?case" form;
  2403   - 'induct' may now use elim-style induction rules without chaining
  2404     facts, using ``missing'' premises from the goal state; this allows
  2405     rules stemming from inductive sets to be applied in unstructured
  2406     scripts, while still benefitting from proper handling of non-atomic
  2407     statements; NB: major inductive premises need to be put first, all
  2408     the rest of the goal is passed through the induction;
  2409   - 'induct' proper support for mutual induction involving non-atomic
  2410     rule statements (uses the new concept of simultaneous goals, see
  2411     below);
  2412   - append all possible rule selections, but only use the first
  2413     success (no backtracking);
  2414   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2415   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2416   - added 'print_induct_rules' (covered by help item in recent Proof
  2417     General versions);
  2418   - moved induct/cases attributes to Pure, methods to Provers;
  2419   - generic method setup instantiated for FOL and HOL;
  2420 
  2421 * Pure: support multiple simultaneous goal statements, for example
  2422 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2423 meta-level mechanism, this acts as if several individual goals had
  2424 been stated separately; in particular common proof methods need to be
  2425 repeated in order to cover all claims; note that a single elimination
  2426 step is *not* sufficient to establish the two conjunctions, so this
  2427 fails:
  2428 
  2429   assume "A & B" then have A and B ..   (*".." fails*)
  2430 
  2431 better use "obtain" in situations as above; alternative refer to
  2432 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2433 
  2434 * Pure: proper integration with ``locales''; unlike the original
  2435 version by Florian Kammller, Isar locales package high-level proof
  2436 contexts rather than raw logical ones (e.g. we admit to include
  2437 attributes everywhere); operations on locales include merge and
  2438 rename; support for implicit arguments (``structures''); simultaneous
  2439 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2440 some examples;
  2441 
  2442 * Pure: the following commands have been ``localized'', supporting a
  2443 target locale specification "(in name)": 'lemma', 'theorem',
  2444 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2445 stored both within the locale and at the theory level (exported and
  2446 qualified by the locale name);
  2447 
  2448 * Pure: theory goals may now be specified in ``long'' form, with
  2449 ad-hoc contexts consisting of arbitrary locale elements. for example
  2450 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2451 definitions may be given, too); the result is a meta-level rule with
  2452 the context elements being discharged in the obvious way;
  2453 
  2454 * Pure: new proof command 'using' allows to augment currently used
  2455 facts after a goal statement ('using' is syntactically analogous to
  2456 'apply', but acts on the goal's facts only); this allows chained facts
  2457 to be separated into parts given before and after a claim, as in
  2458 ``from a and b have C using d and e <proof>'';
  2459 
  2460 * Pure: renamed "antecedent" case to "rule_context";
  2461 
  2462 * Pure: new 'judgment' command records explicit information about the
  2463 object-logic embedding (used by several tools internally); no longer
  2464 use hard-wired "Trueprop";
  2465 
  2466 * Pure: added 'corollary' command;
  2467 
  2468 * Pure: fixed 'token_translation' command;
  2469 
  2470 * Pure: removed obsolete 'exported' attribute;
  2471 
  2472 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2473 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2474 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2475 
  2476 * Pure: method 'atomize' presents local goal premises as object-level
  2477 statements (atomic meta-level propositions); setup controlled via
  2478 rewrite rules declarations of 'atomize' attribute; example
  2479 application: 'induct' method with proper rule statements in improper
  2480 proof *scripts*;
  2481 
  2482 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2483 now consider the syntactic context of assumptions, giving a better
  2484 chance to get type-inference of the arguments right (this is
  2485 especially important for locales);
  2486 
  2487 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2488 mode;
  2489 
  2490 * Pure/obtain: the formal conclusion "thesis", being marked as
  2491 ``internal'', may no longer be reference directly in the text;
  2492 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2493 situations;
  2494 
  2495 * Pure: generic 'sym' attribute which declares a rule both as pure
  2496 'elim?' and for the 'symmetric' operation;
  2497 
  2498 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2499 text; the fixed correlation with particular command syntax has been
  2500 discontinued;
  2501 
  2502 * Pure: new method 'rules' is particularly well-suited for proof
  2503 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2504 but often produces more compact proof terms with less detours;
  2505 
  2506 * Pure/Provers/classical: simplified integration with pure rule
  2507 attributes and methods; the classical "intro?/elim?/dest?"
  2508 declarations coincide with the pure ones; the "rule" method no longer
  2509 includes classically swapped intros; "intro" and "elim" methods no
  2510 longer pick rules from the context; also got rid of ML declarations
  2511 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2512 INCOMPATIBILITY;
  2513 
  2514 * Provers/classical: attribute 'swapped' produces classical inversions
  2515 of introduction rules;
  2516 
  2517 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2518 rules instead of full simplifier context; 'iff' attribute handles
  2519 conditional rules;
  2520 
  2521 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2522 
  2523 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2524 "(permissive)" option to recover old behavior;
  2525 
  2526 * HOL: 'inductive' no longer features separate (collective) attributes
  2527 for 'intros' (was found too confusing);
  2528 
  2529 * HOL: properly declared induction rules less_induct and
  2530 wf_induct_rule;
  2531 
  2532 
  2533 *** HOL ***
  2534 
  2535 * HOL: moved over to sane numeral syntax; the new policy is as
  2536 follows:
  2537 
  2538   - 0 and 1 are polymorphic constants, which are defined on any
  2539   numeric type (nat, int, real etc.);
  2540 
  2541   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2542   binary representation internally;
  2543 
  2544   - type nat has special constructor Suc, and generally prefers Suc 0
  2545   over 1::nat and Suc (Suc 0) over 2::nat;
  2546 
  2547 This change may cause significant problems of INCOMPATIBILITY; here
  2548 are some hints on converting existing sources:
  2549 
  2550   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2551   entities, so expressions involving "-" (unary or binary minus) need
  2552   to be spaced properly;
  2553 
  2554   - existing occurrences of "1" may need to be constraint "1::nat" or
  2555   even replaced by Suc 0; similar for old "2";
  2556 
  2557   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2558 
  2559   - remove all special provisions on numerals in proofs;
  2560 
  2561 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2562 representation (depends on bin_arith_simps in the default context);
  2563 
  2564 * HOL: symbolic syntax for x^2 (numeral 2);
  2565 
  2566 * HOL: the class of all HOL types is now called "type" rather than
  2567 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2568 in axclass/classes, instance/arities, and (usually rare) occurrences
  2569 in typings (of consts etc.); internally the class is called
  2570 "HOL.type", ML programs should refer to HOLogic.typeS;
  2571 
  2572 * HOL/record package improvements:
  2573   - new derived operations "fields" to build a partial record section,
  2574     "extend" to promote a fixed record to a record scheme, and
  2575     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2576     declared as simp by default;
  2577   - shared operations ("more", "fields", etc.) now need to be always
  2578     qualified) --- potential INCOMPATIBILITY;
  2579   - removed "make_scheme" operations (use "make" with "extend") --
  2580     INCOMPATIBILITY;
  2581   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2582   - provides cases/induct rules for use with corresponding Isar
  2583     methods (for concrete records, record schemes, concrete more
  2584     parts, and schematic more parts -- in that order);
  2585   - internal definitions directly based on a light-weight abstract
  2586     theory of product types over typedef rather than datatype;
  2587 
  2588 * HOL: generic code generator for generating executable ML code from
  2589 specifications; specific support for HOL constructs such as inductive
  2590 datatypes and sets, as well as recursive functions; can be invoked
  2591 via 'generate_code' theory section;
  2592 
  2593 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2594 
  2595 * HOL: consolidated and renamed several theories.  In particular:
  2596         Ord.thy has been absorbed into HOL.thy
  2597         String.thy has been absorbed into List.thy
  2598 
  2599 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2600 (beware of argument permutation!);
  2601 
  2602 * HOL: linorder_less_split superseded by linorder_cases;
  2603 
  2604 * HOL/List: "nodups" renamed to "distinct";
  2605 
  2606 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2607 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2608   - Ex_def has changed, now need to use some_eq_ex
  2609 
  2610 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2611 in this (rare) case use:
  2612 
  2613   delSWrapper "split_all_tac"
  2614   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2615 
  2616 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2617 MAY FAIL;
  2618 
  2619 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2620 Isabelle's type classes, ^ on functions and relations has too general
  2621 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2622 necessary to attach explicit type constraints;
  2623 
  2624 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2625 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2626 renamed accordingly (eg "compI" -> "rel_compI").
  2627 
  2628 * HOL: syntax translations now work properly with numerals and records
  2629 expressions;
  2630 
  2631 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2632 of "lam" -- INCOMPATIBILITY;
  2633 
  2634 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2635 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2636 renamed "Product_Type.unit";
  2637 
  2638 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2639 
  2640 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2641 the "cases" method);
  2642 
  2643 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2644 Florian Kammller);
  2645 
  2646 * HOL/IMP: updated and converted to new-style theory format; several
  2647 parts turned into readable document, with proper Isar proof texts and
  2648 some explanations (by Gerwin Klein);
  2649 
  2650 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2651 
  2652 * HOL-Hyperreal is now a logic image;
  2653 
  2654 
  2655 *** HOLCF ***
  2656 
  2657 * Isar: consts/constdefs supports mixfix syntax for continuous
  2658 operations;
  2659 
  2660 * Isar: domain package adapted to new-style theory format, e.g. see
  2661 HOLCF/ex/Dnat.thy;
  2662 
  2663 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2664 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2665 lift.induct_tac, always use UU instead of Undef;
  2666 
  2667 * HOLCF/IMP: updated and converted to new-style theory;
  2668 
  2669 
  2670 *** ZF ***
  2671 
  2672 * Isar: proper integration of logic-specific tools and packages,
  2673 including theory commands '(co)inductive', '(co)datatype',
  2674 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2675 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2676 
  2677 * theory Main no longer includes AC; for the Axiom of Choice, base
  2678 your theory on Main_ZFC;
  2679 
  2680 * the integer library now covers quotients and remainders, with many
  2681 laws relating division to addition, multiplication, etc.;
  2682 
  2683 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2684 typeless version of the formalism;
  2685 
  2686 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2687 format;
  2688 
  2689 * ZF/Induct: new directory for examples of inductive definitions,
  2690 including theory Multiset for multiset orderings; converted to
  2691 new-style theory format;
  2692 
  2693 * ZF: many new theorems about lists, ordinals, etc.;
  2694 
  2695 
  2696 *** General ***
  2697 
  2698 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2699 variable proof controls level of detail: 0 = no proofs (only oracle
  2700 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2701 also ref manual for further ML interfaces;
  2702 
  2703 * Pure/axclass: removed obsolete ML interface
  2704 goal_subclass/goal_arity;
  2705 
  2706 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2707 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2708 separate tokens, so expressions involving minus need to be spaced
  2709 properly;
  2710 
  2711 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2712 rather than "infixl" or "infixr";
  2713 
  2714 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2715 sort constraint specifications in type inference; e.g. "x::_::foo"
  2716 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2717 type variable);
  2718 
  2719 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2720 control output of nested => (types); the default behavior is
  2721 "type_brackets";
  2722 
  2723 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2724 tokens into AST constants;
  2725 
  2726 * Pure/syntax: prefer later declarations of translations and print
  2727 translation functions; potential INCOMPATIBILITY: need to reverse
  2728 multiple declarations for same syntax element constant;
  2729 
  2730 * Pure/show_hyps reset by default (in accordance to existing Isar
  2731 practice);
  2732 
  2733 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2734 addSafter;
  2735 
  2736 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2737 as well;
  2738 
  2739 * system: tested support for MacOS X; should be able to get Isabelle +
  2740 Proof General to work in a plain Terminal after installing Poly/ML
  2741 (e.g. from the Isabelle distribution area) and GNU bash alone
  2742 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2743 support requires further installations, e.g. from
  2744 http://fink.sourceforge.net/);
  2745 
  2746 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2747 
  2748 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2749 of 40 MB), cf. ML_OPTIONS;
  2750 
  2751 * system: Proof General keywords specification is now part of the
  2752 Isabelle distribution (see etc/isar-keywords.el);
  2753 
  2754 * system: support for persistent Proof General sessions (refrain from
  2755 outdating all loaded theories on startup); user may create writable
  2756 logic images like this: ``isabelle -q HOL Test'';
  2757 
  2758 * system: smart selection of Isabelle process versus Isabelle
  2759 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2760 run both "isabelle" and "Isabelle" even if file names are badly
  2761 damaged (executable inspects the case of the first letter of its own
  2762 name); added separate "isabelle-process" and "isabelle-interface";
  2763 
  2764 * system: refrain from any attempt at filtering input streams; no
  2765 longer support ``8bit'' encoding of old isabelle font, instead proper
  2766 iso-latin characters may now be used; the related isatools
  2767 "symbolinput" and "nonascii" have disappeared as well;
  2768 
  2769 * system: removed old "xterm" interface (the print modes "xterm" and
  2770 "xterm_color" are still available for direct use in a suitable
  2771 terminal);
  2772 
  2773 
  2774 
  2775 New in Isabelle99-2 (February 2001)
  2776 -----------------------------------
  2777 
  2778 *** Overview of INCOMPATIBILITIES ***
  2779 
  2780 * HOL: please note that theories in the Library and elsewhere often use the
  2781 new-style (Isar) format; to refer to their theorems in an ML script you must
  2782 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2783 
  2784 * HOL: inductive package no longer splits induction rule aggressively,
  2785 but only as far as specified by the introductions given; the old
  2786 format may be recovered via ML function complete_split_rule or attribute
  2787 'split_rule (complete)';
  2788 
  2789 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2790 gfp_Tarski to gfp_unfold;
  2791 
  2792 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2793 
  2794 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2795 relation); infix "^^" has been renamed "``"; infix "``" has been
  2796 renamed "`"; "univalent" has been renamed "single_valued";
  2797 
  2798 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2799 operation;
  2800 
  2801 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2802 
  2803 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2804 
  2805 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2806 consequence, it is no longer monotonic wrt. the local goal context
  2807 (which is now passed through the inductive cases);
  2808 
  2809 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2810 \<gg> to \<ggreater>;
  2811 
  2812 
  2813 *** Document preparation ***
  2814 
  2815 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2816 available: are "it" for near math-mode best-style output, "sl" for
  2817 slanted text style, and "tt" for plain type-writer; if no
  2818 \isabellestyle command is given, output is according to slanted
  2819 type-writer);
  2820 
  2821 * support sub/super scripts (for single symbols only), input syntax is
  2822 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2823 
  2824 * some more standard symbols; see Appendix A of the system manual for
  2825 the complete list of symbols defined in isabellesym.sty;
  2826 
  2827 * improved isabelle style files; more abstract symbol implementation
  2828 (should now use \isamath{...} and \isatext{...} in custom symbol
  2829 definitions);
  2830 
  2831 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2832 state; Note that presentation of goal states does not conform to
  2833 actual human-readable proof documents.  Please do not include goal
  2834 states into document output unless you really know what you are doing!
  2835 
  2836 * proper indentation of antiquoted output with proportional LaTeX
  2837 fonts;
  2838 
  2839 * no_document ML operator temporarily disables LaTeX document
  2840 generation;
  2841 
  2842 * isatool unsymbolize tunes sources for plain ASCII communication;
  2843 
  2844 
  2845 *** Isar ***
  2846 
  2847 * Pure: Isar now suffers initial goal statements to contain unbound
  2848 schematic variables (this does not conform to actual readable proof
  2849 documents, due to unpredictable outcome and non-compositional proof
  2850 checking); users who know what they are doing may use schematic goals
  2851 for Prolog-style synthesis of proven results;
  2852 
  2853 * Pure: assumption method (an implicit finishing) now handles actual
  2854 rules as well;
  2855 
  2856 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2857 initial goal, declare "that" only as Pure intro (only for single
  2858 steps); the "that" rule assumption may now be involved in implicit
  2859 finishing, thus ".." becomes a feasible for trivial obtains;
  2860 
  2861 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2862 instance proofs may be performed by "..";
  2863 
  2864 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2865 statements as well;
  2866 
  2867 * Pure: more robust selection of calculational rules;
  2868 
  2869 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2870 rule (as well as the assumption rule);
  2871 
  2872 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2873 lemmas, using the graph browser tool;
  2874 
  2875 * Pure: predict failure of "show" in interactive mode;
  2876 
  2877 * Pure: 'thms_containing' now takes actual terms as arguments;
  2878 
  2879 * HOL: improved method 'induct' --- now handles non-atomic goals
  2880 (potential INCOMPATIBILITY); tuned error handling;
  2881 
  2882 * HOL: cases and induct rules now provide explicit hints about the
  2883 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2884 any remaining facts are inserted into the goal verbatim;
  2885 
  2886 * HOL: local contexts (aka cases) may now contain term bindings as
  2887 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2888 the result to be shown in each case;
  2889 
  2890 * HOL: added 'recdef_tc' command;
  2891 
  2892 * isatool convert assists in eliminating legacy ML scripts;
  2893 
  2894 
  2895 *** HOL ***
  2896 
  2897 * HOL/Library: a collection of generic theories to be used together
  2898 with main HOL; the theory loader path already includes this directory
  2899 by default; the following existing theories have been moved here:
  2900 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2901 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2902 
  2903 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2904 modelling and verification task performed in Isabelle/HOL +
  2905 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2906 
  2907 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2908 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2909 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2910 'domain', this makes the theory consistent with mathematical
  2911 literature;
  2912 
  2913 * HOL basics: added overloaded operations "inverse" and "divide"
  2914 (infix "/"), syntax for generic "abs" operation, generic summation
  2915 operator \<Sum>;
  2916 
  2917 * HOL/typedef: simplified package, provide more useful rules (see also
  2918 HOL/subset.thy);
  2919 
  2920 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2921 now expressed as a proper nested rule (old-style tactic scripts may
  2922 require atomize_strip_tac to cope with non-atomic premises);
  2923 
  2924 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2925 to "split_conv" (old name still available for compatibility);
  2926 
  2927 * HOL: improved concrete syntax for strings (e.g. allows translation
  2928 rules with string literals);
  2929 
  2930 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2931  and Fleuriot's mechanization of analysis, including the transcendental
  2932  functions for the reals;
  2933 
  2934 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2935 
  2936 
  2937 *** CTT ***
  2938 
  2939 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2940 "lam" is displayed as TWO lambda-symbols
  2941 
  2942 * CTT: theory Main now available, containing everything (that is, Bool
  2943 and Arith);
  2944 
  2945 
  2946 *** General ***
  2947 
  2948 * Pure: the Simplifier has been implemented properly as a derived rule
  2949 outside of the actual kernel (at last!); the overall performance
  2950 penalty in practical applications is about 50%, while reliability of
  2951 the Isabelle inference kernel has been greatly improved;
  2952 
  2953 * print modes "brackets" and "no_brackets" control output of nested =>
  2954 (types) and ==> (props); the default behaviour is "brackets";
  2955 
  2956 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2957 as assumptions as well;
  2958 
  2959 * system: support Poly/ML 4.0;
  2960 
  2961 * system: isatool install handles KDE version 1 or 2;
  2962 
  2963 
  2964 
  2965 New in Isabelle99-1 (October 2000)
  2966 ----------------------------------
  2967 
  2968 *** Overview of INCOMPATIBILITIES ***
  2969 
  2970 * HOL: simplification of natural numbers is much changed; to partly
  2971 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2972 issue the following ML commands:
  2973 
  2974   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2975   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2976 
  2977 * HOL: simplification no longer dives into case-expressions; this is
  2978 controlled by "t.weak_case_cong" for each datatype t;
  2979 
  2980 * HOL: nat_less_induct renamed to less_induct;
  2981 
  2982 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2983 fixsome to patch .thy and .ML sources automatically;
  2984 
  2985   select_equality  -> some_equality
  2986   select_eq_Ex     -> some_eq_ex
  2987   selectI2EX       -> someI2_ex
  2988   selectI2         -> someI2
  2989   selectI          -> someI
  2990   select1_equality -> some1_equality
  2991   Eps_sym_eq       -> some_sym_eq_trivial
  2992   Eps_eq           -> some_eq_trivial
  2993 
  2994 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2995 
  2996 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2997 instead);
  2998 
  2999 * HOL: the recursion equations generated by 'recdef' are now called
  3000 f.simps instead of f.rules;
  3001 
  3002 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3003 
  3004 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3005 sometimes be needed;
  3006 
  3007 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3008 
  3009 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3010 
  3011 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3012 product is now "<*>" instead of "Times"; the lexicographic product is
  3013 now "<*lex*>" instead of "**";
  3014 
  3015 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3016 of main HOL, but was unused); better use HOL's datatype package;
  3017 
  3018 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3019 the old syntax may be recovered as follows:
  3020 
  3021   syntax (symbols)
  3022     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3023       (infixl "\\<oplus>" 100)
  3024 
  3025 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3026 
  3027 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3028 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3029 internally;
  3030 
  3031 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3032 changed from A/r to A//r;
  3033 
  3034 * ZF: new treatment of arithmetic (nat & int) may break some old
  3035 proofs;
  3036 
  3037 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3038 rulify -> rule_format, elimify -> elim_format, ...);
  3039 
  3040 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3041 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3042 should have to change intro!! to intro? only); replaced "delrule" by
  3043 "rule del";
  3044 
  3045 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3046 
  3047 * Provers: strengthened force_tac by using new first_best_tac;
  3048 
  3049 * LaTeX document preparation: several changes of isabelle.sty (see
  3050 lib/texinputs);
  3051 
  3052 
  3053 *** Document preparation ***
  3054 
  3055 * formal comments (text blocks etc.) in new-style theories may now
  3056 contain antiquotations of thm/prop/term/typ/text to be presented
  3057 according to latex print mode; concrete syntax is like this:
  3058 @{term[show_types] "f(x) = a + x"};
  3059 
  3060 * isatool mkdir provides easy setup of Isabelle session directories,
  3061 including proper document sources;
  3062 
  3063 * generated LaTeX sources are now deleted after successful run
  3064 (isatool document -c); may retain a copy somewhere else via -D option
  3065 of isatool usedir;
  3066 
  3067 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3068 style files, achieving self-contained LaTeX sources and simplifying
  3069 LaTeX debugging;
  3070 
  3071 * old-style theories now produce (crude) LaTeX output as well;
  3072 
  3073 * browser info session directories are now self-contained (may be put
  3074 on WWW server seperately); improved graphs of nested sessions; removed
  3075 graph for 'all sessions';
  3076 
  3077 * several improvements in isabelle style files; \isabellestyle{it}
  3078 produces fake math mode output; \isamarkupheader is now \section by
  3079 default; see lib/texinputs/isabelle.sty etc.;
  3080 
  3081 
  3082 *** Isar ***
  3083 
  3084 * Isar/Pure: local results and corresponding term bindings are now
  3085 subject to Hindley-Milner polymorphism (similar to ML); this
  3086 accommodates incremental type-inference very nicely;
  3087 
  3088 * Isar/Pure: new derived language element 'obtain' supports
  3089 generalized existence reasoning;
  3090 
  3091 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3092 support accumulation of results, without applying any rules yet;
  3093 useful to collect intermediate results without explicit name
  3094 references, and for use with transitivity rules with more than 2
  3095 premises;
  3096 
  3097 * Isar/Pure: scalable support for case-analysis type proofs: new
  3098 'case' language element refers to local contexts symbolically, as
  3099 produced by certain proof methods; internally, case names are attached
  3100 to theorems as "tags";
  3101 
  3102 * Isar/Pure: theory command 'hide' removes declarations from
  3103 class/type/const name spaces;
  3104 
  3105 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3106 indicate potential overloading;
  3107 
  3108 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3109 
  3110 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3111 "{a,b,c}" instead of {a,b,c};
  3112 
  3113 * Isar/Pure now provides its own version of intro/elim/dest
  3114 attributes; useful for building new logics, but beware of confusion
  3115 with the version in Provers/classical;
  3116 
  3117 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3118 case name 'antecedent';
  3119 
  3120 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3121 to the current context is now done automatically);
  3122 
  3123 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3124 for definining proof methods in ML;
  3125 
  3126 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3127 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3128 most cases, one should have to change intro!! to intro? only);
  3129 replaced "delrule" by "rule del";
  3130 
  3131 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3132 'symmetric' attribute (the latter supercedes [RS sym]);
  3133 
  3134 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3135 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3136 well (including splits);
  3137 
  3138 * Isar/Provers: Simplifier and Classical methods now support all kind
  3139 of modifiers used in the past, including 'cong', 'iff', etc.
  3140 
  3141 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3142 of Simplifier and Classical reasoner);
  3143 
  3144 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3145 now support named cases; major packages (inductive, datatype, primrec,
  3146 recdef) support case names and properly name parameters;
  3147 
  3148 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3149 monotonicity conditions are extracted to be proven at end of
  3150 calculations;
  3151 
  3152 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3153 method anyway;
  3154 
  3155 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3156 split_if split_if_asm; datatype package provides theorems foo.splits =
  3157 foo.split foo.split_asm for each datatype;
  3158 
  3159 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3160 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3161 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3162 use "(cases (simplified))" method in proper proof texts);
  3163 
  3164 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3165 
  3166 * Isar: names of theorems etc. may be natural numbers as well;
  3167 
  3168 * Isar: 'pr' command: optional arguments for goals_limit and
  3169 ProofContext.prems_limit; no longer prints theory contexts, but only
  3170 proof states;
  3171 
  3172 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3173 additional print modes to be specified; e.g. "pr(latex)" will print
  3174 proof state according to the Isabelle LaTeX style;
  3175 
  3176 * Isar: improved support for emulating tactic scripts, including proof
  3177 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3178 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3179 (for HOL datatypes);
  3180 
  3181 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3182 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3183 'proof method scripts' have to be in depth-first order;
  3184 
  3185 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3186 
  3187 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3188 should instead use individual commands for printing items
  3189 (print_commands, print_methods etc.);
  3190 
  3191 * Isar: added 'nothing' --- the empty list of theorems;
  3192 
  3193 
  3194 *** HOL ***
  3195 
  3196 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3197 corresponding virtual machine and a specification of its bytecode
  3198 verifier and a lightweight bytecode verifier, including proofs of
  3199 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3200 Cornelia Pusch (see also the homepage of project Bali at
  3201 http://isabelle.in.tum.de/Bali/);
  3202 
  3203 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3204 Clemens Ballarin;
  3205 
  3206 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3207 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3208 Rasmussen;
  3209 
  3210 * HOL/Lattice: fundamental concepts of lattice theory and order
  3211 structures, including duals, properties of bounds versus algebraic
  3212 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3213 Theorem for complete lattices etc.; may also serve as a demonstration
  3214 for abstract algebraic reasoning using axiomatic type classes, and
  3215 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3216 
  3217 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3218 von Oheimb;
  3219 
  3220 * HOL/IMPP: extension of IMP with local variables and mutually
  3221 recursive procedures, by David von Oheimb;
  3222 
  3223 * HOL/Lambda: converted into new-style theory and document;
  3224 
  3225 * HOL/ex/Multiquote: example of multiple nested quotations and
  3226 anti-quotations -- basically a generalized version of de-Bruijn
  3227 representation; very useful in avoiding lifting of operations;
  3228 
  3229 * HOL/record: added general record equality rule to simpset; fixed
  3230 select-update simplification procedure to handle extended records as
  3231 well; admit "r" as field name;
  3232 
  3233 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3234 other numeric types and also as the identity of groups, rings, etc.;
  3235 
  3236 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3237 Types nat and int belong to this axclass;
  3238 
  3239 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3240    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3241    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3242   two terms #m*u and #n*u are replaced by #(m+n)*u
  3243     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3244   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3245     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3246 
  3247 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3248 powerful prover for predicate logic but knows nothing of clasets; see
  3249 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3250 
  3251 * HOL: new version of "case_tac" subsumes both boolean case split and
  3252 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3253 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3254 
  3255 * HOL: simplification no longer dives into case-expressions: only the
  3256 selector expression is simplified, but not the remaining arms; to
  3257 enable full simplification of case-expressions for datatype t, you may
  3258 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3259 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3260 
  3261 * HOL/recdef: the recursion equations generated by 'recdef' for
  3262 function 'f' are now called f.simps instead of f.rules; if all
  3263 termination conditions are proved automatically, these simplification
  3264 rules are added to the simpset, as in primrec; rules may be named
  3265 individually as well, resulting in a separate list of theorems for
  3266 each equation;
  3267 
  3268 * HOL/While is a new theory that provides a while-combinator. It
  3269 permits the definition of tail-recursive functions without the
  3270 provision of a termination measure. The latter is necessary once the
  3271 invariant proof rule for while is applied.
  3272 
  3273 * HOL: new (overloaded) notation for the set of elements below/above
  3274 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3275 
  3276 * HOL: theorems impI, allI, ballI bound as "strip";
  3277 
  3278 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3279 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3280 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3281 
  3282 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3283 
  3284 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3285 main HOL, but was unused);
  3286 
  3287 * HOL: fewer consts declared as global (e.g. have to refer to
  3288 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3289 
  3290 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3291 in case of overlap with user translations (e.g. judgements over
  3292 tuples); (note that the underlying logical represenation is still
  3293 bogus);
  3294 
  3295 
  3296 *** ZF ***
  3297 
  3298 * ZF: simplification automatically cancels common terms in arithmetic
  3299 expressions over nat and int;
  3300 
  3301 * ZF: new treatment of nat to minimize type-checking: all operators
  3302 coerce their operands to a natural number using the function natify,
  3303 making the algebraic laws unconditional;
  3304 
  3305 * ZF: as above, for int: operators coerce their operands to an integer
  3306 using the function intify;
  3307 
  3308 * ZF: the integer library now contains many of the usual laws for the
  3309 orderings, including $<=, and monotonicity laws for $+ and $*;
  3310 
  3311 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3312 simplification;
  3313 
  3314 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3315 to the simplifier and classical reasoner simultaneously;
  3316 
  3317 
  3318 *** General ***
  3319 
  3320 * Provers: blast_tac now handles actual object-logic rules as
  3321 assumptions; note that auto_tac uses blast_tac internally as well;
  3322 
  3323 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3324 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3325 
  3326 * Provers: delrules now handles destruct rules as well (no longer need
  3327 explicit make_elim);
  3328 
  3329 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3330   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3331 use instead the strong form,
  3332   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3333 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3334 from destruct-rules;
  3335 
  3336 * Provers: Simplifier.easy_setup provides a fast path to basic
  3337 Simplifier setup for new object-logics;
  3338 
  3339 * Pure: AST translation rules no longer require constant head on LHS;
  3340 
  3341 * Pure: improved name spaces: ambiguous output is qualified; support
  3342 for hiding of names;
  3343 
  3344 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3345 XSYMBOL_HOME; no longer need to do manual configuration in most
  3346 situations;
  3347 
  3348 * system: compression of ML heaps images may now be controlled via -c
  3349 option of isabelle and isatool usedir (currently only observed by
  3350 Poly/ML);
  3351 
  3352 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3353 useful for remote X11);
  3354 
  3355 * system: provide TAGS file for Isabelle sources;
  3356 
  3357 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3358 order;
  3359 
  3360 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3361 timing flag supersedes proof_timing and Toplevel.trace;
  3362 
  3363 * ML: new combinators |>> and |>>> for incremental transformations
  3364 with secondary results (e.g. certain theory extensions):
  3365 
  3366 * ML: PureThy.add_defs gets additional argument to indicate potential
  3367 overloading (usually false);
  3368 
  3369 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3370 results;
  3371 
  3372 
  3373 
  3374 New in Isabelle99 (October 1999)
  3375 --------------------------------
  3376 
  3377 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3378 
  3379 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3380 are no longer simplified.  (This allows the simplifier to unfold recursive
  3381 functional programs.)  To restore the old behaviour, declare
  3382 
  3383     Delcongs [if_weak_cong];
  3384 
  3385 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3386 complement;
  3387 
  3388 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3389 
  3390 * HOL/datatype: mutual_induct_tac no longer exists --
  3391   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3392 
  3393 * HOL/typedef: fixed type inference for representing set; type
  3394 arguments now have to occur explicitly on the rhs as type constraints;
  3395 
  3396 * ZF: The con_defs part of an inductive definition may no longer refer
  3397 to constants declared in the same theory;
  3398 
  3399 * HOL, ZF: the function mk_cases, generated by the inductive
  3400 definition package, has lost an argument.  To simplify its result, it
  3401 uses the default simpset instead of a supplied list of theorems.
  3402 
  3403 * HOL/List: the constructors of type list are now Nil and Cons;
  3404 
  3405 * Simplifier: the type of the infix ML functions
  3406         setSSolver addSSolver setSolver addSolver
  3407 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3408 for packaging solvers. A solver is created via
  3409         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3410 where the string argument is only a comment.
  3411 
  3412 
  3413 *** Proof tools ***
  3414 
  3415 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3416 decision procedure for linear arithmetic. Currently it is used for
  3417 types `nat', `int', and `real' in HOL (see below); it can, should and
  3418 will be instantiated for other types and logics as well.
  3419 
  3420 * The simplifier now accepts rewrite rules with flexible heads, eg
  3421      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3422   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3423   matching.
  3424 
  3425 
  3426 *** General ***
  3427 
  3428 * New Isabelle/Isar subsystem provides an alternative to traditional
  3429 tactical theorem proving; together with the ProofGeneral/isar user
  3430 interface it offers an interactive environment for developing human
  3431 readable proof documents (Isar == Intelligible semi-automated
  3432 reasoning); for further information see isatool doc isar-ref,
  3433 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3434 
  3435 * improved and simplified presentation of theories: better HTML markup
  3436 (including colors), graph views in several sizes; isatool usedir now
  3437 provides a proper interface for user theories (via -P option); actual
  3438 document preparation based on (PDF)LaTeX is available as well (for
  3439 new-style theories only); see isatool doc system for more information;
  3440 
  3441 * native support for Proof General, both for classic Isabelle and
  3442 Isabelle/Isar;
  3443 
  3444 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3445 using the graph browser tool;
  3446 
  3447 * Isabelle manuals now also available as PDF;
  3448 
  3449 * theory loader rewritten from scratch (may not be fully
  3450 bug-compatible); old loadpath variable has been replaced by show_path,
  3451 add_path, del_path, reset_path functions; new operations such as
  3452 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3453 isatool doc ref);
  3454 
  3455 * improved isatool install: option -k creates KDE application icon,
  3456 option -p DIR installs standalone binaries;
  3457 
  3458 * added ML_PLATFORM setting (useful for cross-platform installations);
  3459 more robust handling of platform specific ML images for SML/NJ;
  3460 
  3461 * the settings environment is now statically scoped, i.e. it is never
  3462 created again in sub-processes invoked from isabelle, isatool, or
  3463 Isabelle;
  3464 
  3465 * path element specification '~~' refers to '$ISABELLE_HOME';
  3466 
  3467 * in locales, the "assumes" and "defines" parts may be omitted if
  3468 empty;
  3469 
  3470 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3471 long arrows);
  3472 
  3473 * new print_mode "HTML";
  3474 
  3475 * new flag show_tags controls display of tags of theorems (which are
  3476 basically just comments that may be attached by some tools);
  3477 
  3478 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3479 mode and goal output format:
  3480 
  3481 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3482 244c244
  3483 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3484 ---
  3485 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3486 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3487 181c181
  3488 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3489 ---
  3490 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3491 
  3492 * function bind_thms stores lists of theorems (cf. bind_thm);
  3493 
  3494 * new shorthand tactics ftac, eatac, datac, fatac;
  3495 
  3496 * qed (and friends) now accept "" as result name; in that case the
  3497 theorem is not stored, but proper checks and presentation of the
  3498 result still apply;
  3499 
  3500 * theorem database now also indexes constants "Trueprop", "all",
  3501 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3502 
  3503 
  3504 *** HOL ***
  3505 
  3506 ** HOL arithmetic **
  3507 
  3508 * There are now decision procedures for linear arithmetic over nat and
  3509 int:
  3510 
  3511 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3512 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3513 are treated as atomic; subformulae not involving type `nat' or `int'
  3514 are ignored; quantified subformulae are ignored unless they are
  3515 positive universal or negative existential. The tactic has to be
  3516 invoked by hand and can be a little bit slow. In particular, the
  3517 running time is exponential in the number of occurrences of `min' and
  3518 `max', and `-' on `nat'.
  3519 
  3520 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3521 (negated) (in)equalities among the premises and the conclusion into
  3522 account (i.e. no compound formulae) and does not know about `min' and
  3523 `max', and `-' on `nat'. It is fast and is used automatically by the
  3524 simplifier.
  3525 
  3526 NB: At the moment, these decision procedures do not cope with mixed
  3527 nat/int formulae where the two parts interact, such as `m < n ==>
  3528 int(m) < int(n)'.
  3529 
  3530 * HOL/Numeral provides a generic theory of numerals (encoded
  3531 efficiently as bit strings); setup for types nat/int/real is in place;
  3532 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3533 int, existing theories and proof scripts may require a few additional
  3534 type constraints;
  3535 
  3536 * integer division and remainder can now be performed on constant
  3537 arguments;
  3538 
  3539 * many properties of integer multiplication, division and remainder
  3540 are now available;
  3541 
  3542 * An interface to the Stanford Validity Checker (SVC) is available through the
  3543 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3544 are proved automatically.  SVC must be installed separately, and its results
  3545 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3546 invocation of the underlying oracle).  For SVC see
  3547   http://verify.stanford.edu/SVC
  3548 
  3549 * IsaMakefile: the HOL-Real target now builds an actual image;
  3550 
  3551 
  3552 ** HOL misc **
  3553 
  3554 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3555 (in Isabelle/Isar) -- by Gertrud Bauer;
  3556 
  3557 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3558 analysis for assembly languages with subtypes;
  3559 
  3560 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3561 -- avoids syntactic ambiguities and treats state, transition, and
  3562 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3563 changed syntax and (many) tactics;
  3564 
  3565 * HOL/inductive: Now also handles more general introduction rules such
  3566   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3567   theorems are now maintained within the theory (maintained via the
  3568   "mono" attribute);
  3569 
  3570 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3571   (using function types) such as
  3572 
  3573   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3574 
  3575 * HOL/record: record_simproc (part of the default simpset) takes care
  3576 of selectors applied to updated records; record_split_tac is no longer
  3577 part of the default claset; update_defs may now be removed from the
  3578 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3579 
  3580   claset_ref () := claset() addSWrapper record_split_wrapper;
  3581   Delsimprocs [record_simproc]
  3582 
  3583 * HOL/typedef: fixed type inference for representing set; type
  3584 arguments now have to occur explicitly on the rhs as type constraints;
  3585 
  3586 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3587 names rather than an ML expression;
  3588 
  3589 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3590 supplied later.  Program schemes can be defined, such as
  3591     "While B C s = (if B s then While B C (C s) else s)"
  3592 where the well-founded relation can be chosen after B and C have been given.
  3593 
  3594 * HOL/List: the constructors of type list are now Nil and Cons;
  3595 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3596 course, ML tools referring to List.list.op # etc. have to be adapted;
  3597 
  3598 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3599 disabled by default; run isabelle with option -m HOL to get back to
  3600 the original Gordon/HOL-style output;
  3601 
  3602 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3603 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3604 
  3605 * HOL basic syntax simplified (more orthogonal): all variants of
  3606 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3607 Eps operator is provided as well: "SOME x. P[x]";
  3608 
  3609 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3610 
  3611 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3612 thus available for user theories;
  3613 
  3614 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3615 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3616 time;
  3617 
  3618 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3619 several times and then mp;
  3620 
  3621 
  3622 *** LK ***
  3623 
  3624 * the notation <<...>> is now available as a notation for sequences of
  3625 formulas;
  3626 
  3627 * the simplifier is now installed
  3628 
  3629 * the axiom system has been generalized (thanks to Soren Heilmann)
  3630 
  3631 * the classical reasoner now has a default rule database
  3632 
  3633 
  3634 *** ZF ***
  3635 
  3636 * new primrec section allows primitive recursive functions to be given
  3637 directly (as in HOL) over datatypes and the natural numbers;
  3638 
  3639 * new tactics induct_tac and exhaust_tac for induction (or case
  3640 analysis) over datatypes and the natural numbers;
  3641 
  3642 * the datatype declaration of type T now defines the recursor T_rec;
  3643 
  3644 * simplification automatically does freeness reasoning for datatype
  3645 constructors;
  3646 
  3647 * automatic type-inference, with AddTCs command to insert new
  3648 type-checking rules;
  3649 
  3650 * datatype introduction rules are now added as Safe Introduction rules
  3651 to the claset;
  3652 
  3653 * the syntax "if P then x else y" is now available in addition to
  3654 if(P,x,y);
  3655 
  3656 
  3657 *** Internal programming interfaces ***
  3658 
  3659 * tuned simplifier trace output; new flag debug_simp;
  3660 
  3661 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3662 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3663 
  3664 * AxClass.axclass_tac lost the theory argument;
  3665 
  3666 * tuned current_goals_markers semantics: begin / end goal avoids
  3667 printing empty lines;
  3668 
  3669 * removed prs and prs_fn hook, which was broken because it did not
  3670 include \n in its semantics, forcing writeln to add one
  3671 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3672 string -> unit if you really want to output text without newline;
  3673 
  3674 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3675 plain output, interface builders may have to enable 'isabelle_font'
  3676 mode to get Isabelle font glyphs as before;
  3677 
  3678 * refined token_translation interface; INCOMPATIBILITY: output length
  3679 now of type real instead of int;
  3680 
  3681 * theory loader actions may be traced via new ThyInfo.add_hook
  3682 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3683 your own database of information attached to *whole* theories -- as
  3684 opposed to intra-theory data slots offered via TheoryDataFun;
  3685 
  3686 * proper handling of dangling sort hypotheses (at last!);
  3687 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3688 extra sort hypotheses that can be witnessed from the type signature;
  3689 the force_strip_shyps flag is gone, any remaining shyps are simply
  3690 left in the theorem (with a warning issued by strip_shyps_warning);
  3691 
  3692 
  3693 
  3694 New in Isabelle98-1 (October 1998)
  3695 ----------------------------------
  3696 
  3697 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3698 
  3699 * several changes of automated proof tools;
  3700 
  3701 * HOL: major changes to the inductive and datatype packages, including
  3702 some minor incompatibilities of theory syntax;
  3703 
  3704 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3705 called `inj_on';
  3706 
  3707 * HOL: removed duplicate thms in Arith:
  3708   less_imp_add_less  should be replaced by  trans_less_add1
  3709   le_imp_add_le      should be replaced by  trans_le_add1
  3710 
  3711 * HOL: unary minus is now overloaded (new type constraints may be
  3712 required);
  3713 
  3714 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3715 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3716 now taken as an integer constant.
  3717 
  3718 * Pure: ML function 'theory_of' renamed to 'theory';
  3719 
  3720 
  3721 *** Proof tools ***
  3722 
  3723 * Simplifier:
  3724   1. Asm_full_simp_tac is now more aggressive.
  3725      1. It will sometimes reorient premises if that increases their power to
  3726         simplify.
  3727      2. It does no longer proceed strictly from left to right but may also
  3728         rotate premises to achieve further simplification.
  3729      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3730      old Asm_full_simp_tac in that it does not rotate premises.
  3731   2. The simplifier now knows a little bit about nat-arithmetic.
  3732 
  3733 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3734 allows for selected deletion of wrappers, by introduction of names for
  3735 wrapper functionals.  This implies that addbefore, addSbefore,
  3736 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3737 and that adding two tactics with the same name overwrites the first
  3738 one (emitting a warning).
  3739   type wrapper = (int -> tactic) -> (int -> tactic)
  3740   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3741   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3742   delWrapper, delSWrapper: claset *  string            -> claset
  3743   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3744 
  3745 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3746 semantics; addbefore now affects only the unsafe part of step_tac
  3747 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3748 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3749 by Force_tac;
  3750 
  3751 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3752 compWrapper; added safe wrapper (and access functions for it);
  3753 
  3754 * HOL/split_all_tac is now much faster and fails if there is nothing
  3755 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3756 and the names of the automatically generated variables have changed.
  3757 split_all_tac has moved within claset() from unsafe wrappers to safe
  3758 wrappers, which means that !!-bound variables are split much more
  3759 aggressively, and safe_tac and clarify_tac now split such variables.
  3760 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3761 Note: the same holds for record_split_tac, which does the job of
  3762 split_all_tac for record fields.
  3763 
  3764 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3765 permanently to the default simpset using Addsplits just like
  3766 Addsimps. They can be removed via Delsplits just like
  3767 Delsimps. Lower-case versions are also available.
  3768 
  3769 * HOL/Simplifier: The rule split_if is now part of the default
  3770 simpset. This means that the simplifier will eliminate all occurrences
  3771 of if-then-else in the conclusion of a goal. To prevent this, you can
  3772 either remove split_if completely from the default simpset by
  3773 `Delsplits [split_if]' or remove it in a specific call of the
  3774 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3775 other case splitting rules to/from the default simpset: every datatype
  3776 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3777 t is the name of the datatype).
  3778 
  3779 * Classical reasoner / Simplifier combination: new force_tac (and
  3780 derivatives Force_tac, force) combines rewriting and classical
  3781 reasoning (and whatever other tools) similarly to auto_tac, but is
  3782 aimed to solve the given subgoal completely.
  3783 
  3784 
  3785 *** General ***
  3786 
  3787 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3788 and `goalw': the theory is no longer needed as an explicit argument -
  3789 the current theory context is used; assumptions are no longer returned
  3790 at the ML-level unless one of them starts with ==> or !!; it is
  3791 recommended to convert to these new commands using isatool fixgoal
  3792 (backup your sources first!);
  3793 
  3794 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3795 the current theory context, and 'theory' to lookup stored theories;
  3796 
  3797 * new theory section 'locale' for declaring constants, assumptions and
  3798 definitions that have local scope;
  3799 
  3800 * new theory section 'nonterminals' for purely syntactic types;
  3801 
  3802 * new theory section 'setup' for generic ML setup functions
  3803 (e.g. package initialization);
  3804 
  3805 * the distribution now includes Isabelle icons: see
  3806 lib/logo/isabelle-{small,tiny}.xpm;
  3807 
  3808 * isatool install - install binaries with absolute references to
  3809 ISABELLE_HOME/bin;
  3810 
  3811 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3812 
  3813 * print mode 'emacs' reserved for Isamode;
  3814 
  3815 * support multiple print (ast) translations per constant name;
  3816 
  3817 * theorems involving oracles are now printed with a suffixed [!];
  3818 
  3819 
  3820 *** HOL ***
  3821 
  3822 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3823 
  3824 * HOL/inductive package reorganized and improved: now supports mutual
  3825 definitions such as
  3826 
  3827   inductive EVEN ODD
  3828     intrs
  3829       null "0 : EVEN"
  3830       oddI "n : EVEN ==> Suc n : ODD"
  3831       evenI "n : ODD ==> Suc n : EVEN"
  3832 
  3833 new theorem list "elims" contains an elimination rule for each of the
  3834 recursive sets; inductive definitions now handle disjunctive premises
  3835 correctly (also ZF);
  3836 
  3837 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3838 "mutual_induct" no longer exists - the induction rule is always
  3839 contained in "induct";
  3840 
  3841 
  3842 * HOL/datatype package re-implemented and greatly improved: now
  3843 supports mutually recursive datatypes such as
  3844 
  3845   datatype
  3846     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3847             | SUM ('a aexp) ('a aexp)
  3848             | DIFF ('a aexp) ('a aexp)
  3849             | NUM 'a
  3850   and
  3851     'a bexp = LESS ('a aexp) ('a aexp)
  3852             | AND ('a bexp) ('a bexp)
  3853             | OR ('a bexp) ('a bexp)
  3854 
  3855 as well as indirectly recursive datatypes such as
  3856 
  3857   datatype
  3858     ('a, 'b) term = Var 'a
  3859                   | App 'b ((('a, 'b) term) list)
  3860 
  3861 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3862 induction on mutually / indirectly recursive datatypes.
  3863 
  3864 Primrec equations are now stored in theory and can be accessed via
  3865 <function_name>.simps.
  3866 
  3867 INCOMPATIBILITIES:
  3868 
  3869   - Theories using datatypes must now have theory Datatype as an
  3870     ancestor.
  3871   - The specific <typename>.induct_tac no longer exists - use the
  3872     generic induct_tac instead.
  3873   - natE has been renamed to nat.exhaust - use exhaust_tac
  3874     instead of res_inst_tac ... natE. Note that the variable
  3875     names in nat.exhaust differ from the names in natE, this
  3876     may cause some "fragile" proofs to fail.
  3877   - The theorems split_<typename>_case and split_<typename>_case_asm
  3878     have been renamed to <typename>.split and <typename>.split_asm.
  3879   - Since default sorts of type variables are now handled correctly,
  3880     some datatype definitions may have to be annotated with explicit
  3881     sort constraints.
  3882   - Primrec definitions no longer require function name and type
  3883     of recursive argument.
  3884 
  3885 Consider using isatool fixdatatype to adapt your theories and proof
  3886 scripts to the new package (backup your sources first!).
  3887 
  3888 
  3889 * HOL/record package: considerably improved implementation; now
  3890 includes concrete syntax for record types, terms, updates; theorems
  3891 for surjective pairing and splitting !!-bound record variables; proof
  3892 support is as follows:
  3893 
  3894   1) standard conversions (selectors or updates applied to record
  3895 constructor terms) are part of the standard simpset;
  3896 
  3897   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3898 made part of standard simpset and claset via addIffs;
  3899 
  3900   3) a tactic for record field splitting (record_split_tac) is part of
  3901 the standard claset (addSWrapper);
  3902 
  3903 To get a better idea about these rules you may retrieve them via
  3904 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3905 the name of your record type.
  3906 
  3907 The split tactic 3) conceptually simplifies by the following rule:
  3908 
  3909   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3910 
  3911 Thus any record variable that is bound by meta-all will automatically
  3912 blow up into some record constructor term, consequently the
  3913 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3914 solve record problems automatically.
  3915 
  3916 
  3917 * reorganized the main HOL image: HOL/Integ and String loaded by
  3918 default; theory Main includes everything;
  3919 
  3920 * automatic simplification of integer sums and comparisons, using cancellation;
  3921 
  3922 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3923 
  3924 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3925 
  3926 * many new identities for unions, intersections, set difference, etc.;
  3927 
  3928 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3929 called split_if, split_split, split_sum_case and split_nat_case (to go
  3930 with add/delsplits);
  3931 
  3932 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3933 (?x::unit) = (); this is made part of the default simpset, which COULD
  3934 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3935 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3936 unit_abs_eta_conv is added in order to counter the effect of
  3937 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3938 %u.f();
  3939 
  3940 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3941 makes more sense);
  3942 
  3943 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3944   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3945   disjointness reasoning but breaking a few old proofs.
  3946 
  3947 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3948 to 'converse' from 'inverse' (for compatibility with ZF and some
  3949 literature);
  3950 
  3951 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3952 the well-founded relation;
  3953 
  3954 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3955     Compl A.  The "Compl" syntax remains available as input syntax for this
  3956     release ONLY.
  3957 
  3958 * HOL/Update: new theory of function updates:
  3959     f(a:=b) == %x. if x=a then b else f x
  3960 may also be iterated as in f(a:=b,c:=d,...);
  3961 
  3962 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3963 
  3964 * HOL/List:
  3965   - new function list_update written xs[i:=v] that updates the i-th
  3966     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3967   - new function `upt' written [i..j(] which generates the list
  3968     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3969     bound write [i..j], which is a shorthand for [i..j+1(].
  3970   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3971 
  3972 * HOL/Arith:
  3973   - removed 'pred' (predecessor) function;
  3974   - generalized some theorems about n-1;
  3975   - many new laws about "div" and "mod";
  3976   - new laws about greatest common divisors (see theory ex/Primes);
  3977 
  3978 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3979 instead of "inverse";
  3980 
  3981 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3982   of the multiset ordering;
  3983 
  3984 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3985   (not included by default);
  3986 
  3987 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3988 
  3989 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3990   programs, i.e. different program variables may have different types.
  3991 
  3992 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3993   [previously, this check worked only if the rewrite rule was unconditional]
  3994   Now rew can involve either definitions or equalities (either == or =).
  3995 
  3996 
  3997 *** ZF ***
  3998 
  3999 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4000   only the theorems proved on ZF.ML;
  4001 
  4002 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4003   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4004   disjointness reasoning but breaking a few old proofs.
  4005 
  4006 * ZF/Update: new theory of function updates
  4007     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4008   may also be iterated as in f(a:=b,c:=d,...);
  4009 
  4010 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4011 
  4012 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4013   [previously, this check worked only if the rewrite rule was unconditional]
  4014   Now rew can involve either definitions or equalities (either == or =).
  4015 
  4016 * case_tac provided for compatibility with HOL
  4017     (like the old excluded_middle_tac, but with subgoals swapped)
  4018 
  4019 
  4020 *** Internal programming interfaces ***
  4021 
  4022 * Pure: several new basic modules made available for general use, see
  4023 also src/Pure/README;
  4024 
  4025 * improved the theory data mechanism to support encapsulation (data
  4026 kind name replaced by private Object.kind, acting as authorization
  4027 key); new type-safe user interface via functor TheoryDataFun; generic
  4028 print_data function becomes basically useless;
  4029 
  4030 * removed global_names compatibility flag -- all theory declarations
  4031 are qualified by default;
  4032 
  4033 * module Pure/Syntax now offers quote / antiquote translation
  4034 functions (useful for Hoare logic etc. with implicit dependencies);
  4035 see HOL/ex/Antiquote for an example use;
  4036 
  4037 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4038 cterm -> thm;
  4039 
  4040 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4041 subgoal;
  4042 
  4043 * Display.print_goals function moved to Locale.print_goals;
  4044 
  4045 * standard print function for goals supports current_goals_markers
  4046 variable for marking begin of proof, end of proof, start of goal; the
  4047 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4048 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4049 for example;
  4050 
  4051 
  4052 
  4053 New in Isabelle98 (January 1998)
  4054 --------------------------------
  4055 
  4056 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4057 
  4058 * changed lexical syntax of terms / types: dots made part of long
  4059 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4060 
  4061 * simpset (and claset) reference variable replaced by functions
  4062 simpset / simpset_ref;
  4063 
  4064 * no longer supports theory aliases (via merge) and non-trivial
  4065 implicit merge of thms' signatures;
  4066 
  4067 * most internal names of constants changed due to qualified names;
  4068 
  4069 * changed Pure/Sequence interface (see Pure/seq.ML);
  4070 
  4071 
  4072 *** General Changes ***
  4073 
  4074 * hierachically structured name spaces (for consts, types, axms, thms
  4075 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4076 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4077 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4078 long_names for fully qualified output names; NOTE: ML programs
  4079 (special tactics, packages etc.) referring to internal names may have
  4080 to be adapted to cope with fully qualified names; in case of severe
  4081 backward campatibility problems try setting 'global_names' at compile
  4082 time to have enrything declared within a flat name space; one may also
  4083 fine tune name declarations in theories via the 'global' and 'local'
  4084 section;
  4085 
  4086 * reimplemented the implicit simpset and claset using the new anytype
  4087 data filed in signatures; references simpset:simpset ref etc. are
  4088 replaced by functions simpset:unit->simpset and
  4089 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4090 to patch your ML files accordingly;
  4091 
  4092 * HTML output now includes theory graph data for display with Java
  4093 applet or isatool browser; data generated automatically via isatool
  4094 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4095 
  4096 * defs may now be conditional; improved rewrite_goals_tac to handle
  4097 conditional equations;
  4098 
  4099 * defs now admits additional type arguments, using TYPE('a) syntax;
  4100 
  4101 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4102 creates a new theory node; implicit merge of thms' signatures is
  4103 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4104 transfer:theory->thm->thm in (rare) cases;
  4105 
  4106 * improved handling of draft signatures / theories; draft thms (and
  4107 ctyps, cterms) are automatically promoted to real ones;
  4108 
  4109 * slightly changed interfaces for oracles: admit many per theory, named
  4110 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4111 
  4112 * print_goals: optional output of const types (set show_consts and
  4113 show_types);
  4114 
  4115 * improved output of warnings (###) and errors (***);
  4116 
  4117 * subgoal_tac displays a warning if the new subgoal has type variables;
  4118 
  4119 * removed old README and Makefiles;
  4120 
  4121 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4122 
  4123 * removed obsolete init_pps and init_database;
  4124 
  4125 * deleted the obsolete tactical STATE, which was declared by
  4126     fun STATE tacfun st = tacfun st st;
  4127 
  4128 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4129 (which abbreviates $HOME);
  4130 
  4131 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4132 use isatool fixseq to adapt your ML programs (this works for fully
  4133 qualified references to the Sequence structure only!);
  4134 
  4135 * use_thy no longer requires writable current directory; it always
  4136 reloads .ML *and* .thy file, if either one is out of date;
  4137 
  4138 
  4139 *** Classical Reasoner ***
  4140 
  4141 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4142 tactics that use classical reasoning to simplify a subgoal without
  4143 splitting it into several subgoals;
  4144 
  4145 * Safe_tac: like safe_tac but uses the default claset;
  4146 
  4147 
  4148 *** Simplifier ***
  4149 
  4150 * added simplification meta rules:
  4151     (asm_)(full_)simplify: simpset -> thm -> thm;
  4152 
  4153 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4154 logics (again);
  4155 
  4156 * added prems argument to simplification procedures;
  4157 
  4158 * HOL, FOL, ZF: added infix function `addsplits':
  4159   instead of `<simpset> setloop (split_tac <thms>)'
  4160   you can simply write `<simpset> addsplits <thms>'
  4161 
  4162 
  4163 *** Syntax ***
  4164 
  4165 * TYPE('a) syntax for type reflection terms;
  4166 
  4167 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4168 
  4169 * pretty printer: changed order of mixfix annotation preference (again!);
  4170 
  4171 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4172 
  4173 
  4174 *** HOL ***
  4175 
  4176 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4177   with `addloop' of the simplifier to faciliate case splitting in premises.
  4178 
  4179 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4180 
  4181 * HOL/Auth: new protocol proofs including some for the Internet
  4182   protocol TLS;
  4183 
  4184 * HOL/Map: new theory of `maps' a la VDM;
  4185 
  4186 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4187 cancelling out common nat summands from =, <, <= (in)equalities, or
  4188 differences; simplification procedures nat_cancel_factor for
  4189 cancelling common factor from =, <, <= (in)equalities over natural
  4190 sums; nat_cancel contains both kinds of procedures, it is installed by
  4191 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4192 
  4193 * HOL/simplifier: terms of the form
  4194   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4195   are rewritten to
  4196   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4197   and those of the form
  4198   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4199   are rewritten to
  4200   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4201 
  4202 * HOL/datatype
  4203   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4204 
  4205   P(t_case f1 ... fn x) =
  4206      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4207         ...
  4208        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4209      )
  4210 
  4211   and a theorem `split_t_case_asm' of the form
  4212 
  4213   P(t_case f1 ... fn x) =
  4214     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4215         ...
  4216        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4217      )
  4218   which can be added to a simpset via `addsplits'. The existing theorems
  4219   expand_list_case and expand_option_case have been renamed to
  4220   split_list_case and split_option_case.
  4221 
  4222 * HOL/Arithmetic:
  4223   - `pred n' is automatically converted to `n-1'.
  4224     Users are strongly encouraged not to use `pred' any longer,
  4225     because it will disappear altogether at some point.
  4226   - Users are strongly encouraged to write "0 < n" rather than
  4227     "n ~= 0". Theorems and proof tools have been modified towards this
  4228     `standard'.
  4229 
  4230 * HOL/Lists:
  4231   the function "set_of_list" has been renamed "set" (and its theorems too);
  4232   the function "nth" now takes its arguments in the reverse order and
  4233   has acquired the infix notation "!" as in "xs!n".
  4234 
  4235 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4236 
  4237 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4238   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4239 
  4240 * HOL/record: extensible records with schematic structural subtyping
  4241 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4242 still lacks various theorems and concrete record syntax;
  4243 
  4244 
  4245 *** HOLCF ***
  4246 
  4247 * removed "axioms" and "generated by" sections;
  4248 
  4249 * replaced "ops" section by extended "consts" section, which is capable of
  4250   handling the continuous function space "->" directly;
  4251 
  4252 * domain package:
  4253   . proves theorems immediately and stores them in the theory,
  4254   . creates hierachical name space,
  4255   . now uses normal mixfix annotations (instead of cinfix...),
  4256   . minor changes to some names and values (for consistency),
  4257   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4258   . separator between mutual domain defs: changed "," to "and",
  4259   . improved handling of sort constraints;  now they have to
  4260     appear on the left-hand side of the equations only;
  4261 
  4262 * fixed LAM <x,y,zs>.b syntax;
  4263 
  4264 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4265 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4266 
  4267 
  4268 *** FOL and ZF ***
  4269 
  4270 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4271   with `addloop' of the simplifier to faciliate case splitting in premises.
  4272 
  4273 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4274 in HOL, they strip ALL and --> from proved theorems;
  4275 
  4276 
  4277 
  4278 New in Isabelle94-8 (May 1997)
  4279 ------------------------------
  4280 
  4281 *** General Changes ***
  4282 
  4283 * new utilities to build / run / maintain Isabelle etc. (in parts
  4284 still somewhat experimental); old Makefiles etc. still functional;
  4285 
  4286 * new 'Isabelle System Manual';
  4287 
  4288 * INSTALL text, together with ./configure and ./build scripts;
  4289 
  4290 * reimplemented type inference for greater efficiency, better error
  4291 messages and clean internal interface;
  4292 
  4293 * prlim command for dealing with lots of subgoals (an easier way of
  4294 setting goals_limit);
  4295 
  4296 
  4297 *** Syntax ***
  4298 
  4299 * supports alternative (named) syntax tables (parser and pretty
  4300 printer); internal interface is provided by add_modesyntax(_i);
  4301 
  4302 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4303 be used in conjunction with the Isabelle symbol font; uses the
  4304 "symbols" syntax table;
  4305 
  4306 * added token_translation interface (may translate name tokens in
  4307 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4308 the current print_mode); IMPORTANT: user print translation functions
  4309 are responsible for marking newly introduced bounds
  4310 (Syntax.mark_boundT);
  4311 
  4312 * token translations for modes "xterm" and "xterm_color" that display
  4313 names in bold, underline etc. or colors (which requires a color
  4314 version of xterm);
  4315 
  4316 * infixes may now be declared with names independent of their syntax;
  4317 
  4318 * added typed_print_translation (like print_translation, but may
  4319 access type of constant);
  4320 
  4321 
  4322 *** Classical Reasoner ***
  4323 
  4324 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4325 some limitations.  Blast_tac...
  4326   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4327   + ignores elimination rules that don't have the correct format
  4328         (the conclusion MUST be a formula variable)
  4329   + ignores types, which can make HOL proofs fail
  4330   + rules must not require higher-order unification, e.g. apply_type in ZF
  4331     [message "Function Var's argument not a bound variable" relates to this]
  4332   + its proof strategy is more general but can actually be slower
  4333 
  4334 * substitution with equality assumptions no longer permutes other
  4335 assumptions;
  4336 
  4337 * minor changes in semantics of addafter (now called addaltern); renamed
  4338 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4339 (and access functions for it);
  4340 
  4341 * improved combination of classical reasoner and simplifier:
  4342   + functions for handling clasimpsets
  4343   + improvement of addss: now the simplifier is called _after_ the
  4344     safe steps.
  4345   + safe variant of addss called addSss: uses safe simplifications
  4346     _during_ the safe steps. It is more complete as it allows multiple
  4347     instantiations of unknowns (e.g. with slow_tac).
  4348 
  4349 *** Simplifier ***
  4350 
  4351 * added interface for simplification procedures (functions that
  4352 produce *proven* rewrite rules on the fly, depending on current
  4353 redex);
  4354 
  4355 * ordering on terms as parameter (used for ordered rewriting);
  4356 
  4357 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4358 
  4359 * the solver is now split into a safe and an unsafe part.
  4360 This should be invisible for the normal user, except that the
  4361 functions setsolver and addsolver have been renamed to setSolver and
  4362 addSolver; added safe_asm_full_simp_tac;
  4363 
  4364 
  4365 *** HOL ***
  4366 
  4367 * a generic induction tactic `induct_tac' which works for all datatypes and
  4368 also for type `nat';
  4369 
  4370 * a generic case distinction tactic `exhaust_tac' which works for all
  4371 datatypes and also for type `nat';
  4372 
  4373 * each datatype comes with a function `size';
  4374 
  4375 * patterns in case expressions allow tuple patterns as arguments to
  4376 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4377 
  4378 * primrec now also works with type nat;
  4379 
  4380 * recdef: a new declaration form, allows general recursive functions to be
  4381 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4382 
  4383 * the constant for negation has been renamed from "not" to "Not" to
  4384 harmonize with FOL, ZF, LK, etc.;
  4385 
  4386 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4387 infinite lists;
  4388 
  4389 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4390 
  4391 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4392 problems in commutative rings, using axiomatic type classes for + and *;
  4393 
  4394 * more examples in HOL/MiniML and HOL/Auth;
  4395 
  4396 * more default rewrite rules for quantifiers, union/intersection;
  4397 
  4398 * a new constant `arbitrary == @x.False';
  4399 
  4400 * HOLCF/IOA replaces old HOL/IOA;
  4401 
  4402 * HOLCF changes: derived all rules and arities
  4403   + axiomatic type classes instead of classes
  4404   + typedef instead of faking type definitions
  4405   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4406   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4407   + eliminated the types void, one, tr
  4408   + use unit lift and bool lift (with translations) instead of one and tr
  4409   + eliminated blift from Lift3.thy (use Def instead of blift)
  4410   all eliminated rules are derived as theorems --> no visible changes ;
  4411 
  4412 
  4413 *** ZF ***
  4414 
  4415 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4416 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4417 as ZF_cs addSIs [equalityI];
  4418 
  4419 
  4420 
  4421 New in Isabelle94-7 (November 96)
  4422 ---------------------------------
  4423 
  4424 * allowing negative levels (as offsets) in prlev and choplev;
  4425 
  4426 * super-linear speedup for large simplifications;
  4427 
  4428 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4429 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4430 FAIL); can suppress it using the command Delsimps (ex_simps @
  4431 all_simps); De Morgan laws are also now included, by default;
  4432 
  4433 * improved printing of ==>  :  ~:
  4434 
  4435 * new object-logic "Sequents" adds linear logic, while replacing LK
  4436 and Modal (thanks to Sara Kalvala);
  4437 
  4438 * HOL/Auth: correctness proofs for authentication protocols;
  4439 
  4440 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4441 examples on HOL/Auth);
  4442 
  4443 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4444 the rewriter and classical reasoner simultaneously;
  4445 
  4446 * function uresult no longer returns theorems in "standard" format;
  4447 regain previous version by: val uresult = standard o uresult;
  4448 
  4449 
  4450 
  4451 New in Isabelle94-6
  4452 -------------------
  4453 
  4454 * oracles -- these establish an interface between Isabelle and trusted
  4455 external reasoners, which may deliver results as theorems;
  4456 
  4457 * proof objects (in particular record all uses of oracles);
  4458 
  4459 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4460 
  4461 * "constdefs" section in theory files;
  4462 
  4463 * "primrec" section (HOL) no longer requires names;
  4464 
  4465 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4466 
  4467 
  4468 
  4469 New in Isabelle94-5
  4470 -------------------
  4471 
  4472 * reduced space requirements;
  4473 
  4474 * automatic HTML generation from theories;
  4475 
  4476 * theory files no longer require "..." (quotes) around most types;
  4477 
  4478 * new examples, including two proofs of the Church-Rosser theorem;
  4479 
  4480 * non-curried (1994) version of HOL is no longer distributed;
  4481 
  4482 
  4483 
  4484 New in Isabelle94-4
  4485 -------------------
  4486 
  4487 * greatly reduced space requirements;
  4488 
  4489 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4490 
  4491 * searchable theorem database (see the section "Retrieving theorems" on
  4492 page 8 of the Reference Manual);
  4493 
  4494 * new examples, including Grabczewski's monumental case study of the
  4495 Axiom of Choice;
  4496 
  4497 * The previous version of HOL renamed to Old_HOL;
  4498 
  4499 * The new version of HOL (previously called CHOL) uses a curried syntax
  4500 for functions.  Application looks like f a b instead of f(a,b);
  4501 
  4502 * Mutually recursive inductive definitions finally work in HOL;
  4503 
  4504 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4505 translates to the operator "split";
  4506 
  4507 
  4508 
  4509 New in Isabelle94-3
  4510 -------------------
  4511 
  4512 * new infix operator, addss, allowing the classical reasoner to
  4513 perform simplification at each step of its search.  Example:
  4514         fast_tac (cs addss ss)
  4515 
  4516 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4517 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4518 look like (a,b) instead of <a,b>;
  4519 
  4520 * PLEASE NOTE: CHOL will eventually replace HOL!
  4521 
  4522 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4523 It translates to the operator "split".  A new theory of integers is available;
  4524 
  4525 * In ZF, integer numerals now denote two's-complement binary integers.
  4526 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4527 
  4528 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4529 of the Axiom of Choice;
  4530 
  4531 
  4532 
  4533 New in Isabelle94-2
  4534 -------------------
  4535 
  4536 * Significantly faster resolution;
  4537 
  4538 * the different sections in a .thy file can now be mixed and repeated
  4539 freely;
  4540 
  4541 * Database of theorems for FOL, HOL and ZF.  New
  4542 commands including qed, qed_goal and bind_thm store theorems in the database.
  4543 
  4544 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4545 a given theory (thms_of), or find out what theory a theorem was proved in
  4546 (theory_of_thm);
  4547 
  4548 * Bugs fixed in the inductive definition and datatype packages;
  4549 
  4550 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4551 and HOL_dup_cs obsolete;
  4552 
  4553 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4554 have been removed;
  4555 
  4556 * Simpler definition of function space in ZF;
  4557 
  4558 * new results about cardinal and ordinal arithmetic in ZF;
  4559 
  4560 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4561 types;
  4562 
  4563 
  4564 $Id$