NEWS
author huffman
Thu Jun 21 22:30:58 2007 +0200 (2007-06-21)
changeset 23468 d27d79a47592
parent 23449 dd874e6a3282
child 23478 26a5ef187e8b
permissions -rw-r--r--
changed simp rules for of_nat
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * More uniform information about legacy features, notably a
    10 warning/error of "Legacy feature: ...", depending on the state of the
    11 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
    12 legacy features will disappear eventually.
    13 
    14 * Theory syntax: the header format ``theory A = B + C:'' has been
    15 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    16 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    17 
    18 * Theory syntax: the old non-Isar theory file format has been
    19 discontinued altogether.  Note that ML proof scripts may still be used
    20 with Isar theories; migration is usually quite simple with the ML
    21 function use_legacy_bindings.  INCOMPATIBILITY.
    22 
    23 * Theory syntax: some popular names (e.g. 'class', 'declaration',
    24 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
    25 quotes.
    26 
    27 * Legacy goal package: reduced interface to the bare minimum required
    28 to keep existing proof scripts running.  Most other user-level
    29 functions are now part of the OldGoals structure, which is *not* open
    30 by default (consider isatool expandshort before open OldGoals).
    31 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    32 these tend to cause confusion about the actual goal (!) context being
    33 used here, which is not necessarily the same as the_context().
    34 
    35 * Command 'find_theorems': supports "*" wild-card in "name:"
    36 criterion; "with_dups" option.  Certain ProofGeneral versions might
    37 support a specific search form (see ProofGeneral/CHANGES).
    38 
    39 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
    40 by default, which means that "prems" (and also "fixed variables") are
    41 suppressed from proof state output.  Note that the ProofGeneral
    42 settings mechanism allows to change and save options persistently, but
    43 older versions of Isabelle will fail to start up if a negative prems
    44 limit is imposed.
    45 
    46 * Local theory targets may be specified by non-nested blocks of
    47 ``context/locale/class ... begin'' followed by ``end''.  The body may
    48 contain definitions, theorems etc., including any derived mechanism
    49 that has been implemented on top of these primitives.  This concept
    50 generalizes the existing ``theorem (in ...)'' towards more versatility
    51 and scalability.
    52 
    53 * Proof General interface: proper undo of final 'end' command;
    54 discontinued Isabelle/classic mode (ML proof scripts).
    55 
    56 
    57 *** Document preparation ***
    58 
    59 * Added antiquotation @{theory name} which prints the given name,
    60 after checking that it refers to a valid ancestor theory in the
    61 current context.
    62 
    63 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    64 check the given source text as ML type/structure, printing verbatim.
    65 
    66 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
    67 "c args == rhs" given in the current context.  (Any number of
    68 arguments may be given on the LHS.)
    69 
    70 
    71 
    72 *** Pure ***
    73 
    74 * code generator: consts in 'consts_code' Isar commands are now referred
    75   to by usual term syntax (including optional type annotations).
    76 
    77 * code generator: 
    78   - Isar 'definition's, 'constdef's and primitive instance definitions are added
    79     explicitly to the table of defining equations
    80   - primitive definitions are not used as defining equations by default any longer
    81   - defining equations are now definitly restricted to meta "==" and object
    82         equality "="
    83   - HOL theories have been adopted accordingly
    84 
    85 * class_package.ML offers a combination of axclasses and locales to
    86 achieve Haskell-like type classes in Isabelle.  See
    87 HOL/ex/Classpackage.thy for examples.
    88 
    89 * Yet another code generator framework allows to generate executable
    90 code for ML and Haskell (including "class"es).  A short usage sketch:
    91 
    92     internal compilation:
    93         code_gen <list of constants (term syntax)> (SML #)
    94     writing SML code to a file:
    95         code_gen <list of constants (term syntax)> (SML <filename>)
    96     writing OCaml code to a file:
    97         code_gen <list of constants (term syntax)> (OCaml <filename>)
    98     writing Haskell code to a bunch of files:
    99         code_gen <list of constants (term syntax)> (Haskell <filename>)
   100 
   101 Reasonable default setup of framework in HOL/Main.
   102 
   103 Theorem attributs for selecting and transforming function equations theorems:
   104 
   105     [code fun]:        select a theorem as function equation for a specific constant
   106     [code fun del]:    deselect a theorem as function equation for a specific constant
   107     [code inline]:     select an equation theorem for unfolding (inlining) in place
   108     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   109 
   110 User-defined serializations (target in {SML, OCaml, Haskell}):
   111 
   112     code_const <and-list of constants (term syntax)>
   113       {(target) <and-list of const target syntax>}+
   114 
   115     code_type <and-list of type constructors>
   116       {(target) <and-list of type target syntax>}+
   117 
   118     code_instance <and-list of instances>
   119       {(target)}+
   120         where instance ::= <type constructor> :: <class>
   121 
   122     code_class <and_list of classes>
   123       {(target) <and-list of class target syntax>}+
   124         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   125 
   126 code_instance and code_class only apply to target Haskell.
   127 
   128 See HOL theories and HOL/ex/Codegenerator*.thy for usage examples.
   129 Doc/Isar/Advanced/Codegen/ provides a tutorial.
   130 
   131 * Command 'no_translations' removes translation rules from theory
   132 syntax.
   133 
   134 * Overloaded definitions are now actually checked for acyclic
   135 dependencies.  The overloading scheme is slightly more general than
   136 that of Haskell98, although Isabelle does not demand an exact
   137 correspondence to type class and instance declarations.
   138 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   139 exotic versions of overloading -- at the discretion of the user!
   140 
   141 Polymorphic constants are represented via type arguments, i.e. the
   142 instantiation that matches an instance against the most general
   143 declaration given in the signature.  For example, with the declaration
   144 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   145 as c(nat).  Overloading is essentially simultaneous structural
   146 recursion over such type arguments.  Incomplete specification patterns
   147 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   148 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   149 Command 'print_theory' outputs the normalized system of recursive
   150 equations, see section "definitions".
   151 
   152 * Isar: method "assumption" (and implicit closing of subproofs) now
   153 takes simple non-atomic goal assumptions into account: after applying
   154 an assumption as a rule the resulting subgoals are solved by atomic
   155 assumption steps.  This is particularly useful to finish 'obtain'
   156 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   157 without referring to the original premise "!!x. P x ==> thesis" in the
   158 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   159 more permissive.
   160 
   161 * Isar: implicit use of prems from the Isar proof context is
   162 considered a legacy feature.  Common applications like ``have A .''
   163 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   164 referencing facts explicitly here improves readability and
   165 maintainability of proof texts.
   166 
   167 * Isar: improper proof element 'guess' is like 'obtain', but derives
   168 the obtained context from the course of reasoning!  For example:
   169 
   170   assume "EX x y. A x & B y"   -- "any previous fact"
   171   then guess x and y by clarify
   172 
   173 This technique is potentially adventurous, depending on the facts and
   174 proof tools being involved here.
   175 
   176 * Isar: known facts from the proof context may be specified as literal
   177 propositions, using ASCII back-quote syntax.  This works wherever
   178 named facts used to be allowed so far, in proof commands, proof
   179 methods, attributes etc.  Literal facts are retrieved from the context
   180 according to unification of type and term parameters.  For example,
   181 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   182 theorems in the current context, then these are valid literal facts:
   183 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   184 
   185 There is also a proof method "fact" which does the same composition
   186 for explicit goal states, e.g. the following proof texts coincide with
   187 certain special cases of literal facts:
   188 
   189   have "A" by fact                 ==  note `A`
   190   have "A ==> B" by fact           ==  note `A ==> B`
   191   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   192   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   193 
   194 * Isar: ":" (colon) is no longer a symbolic identifier character in
   195 outer syntax.  Thus symbolic identifiers may be used without
   196 additional white space in declarations like this: ``assume *: A''.
   197 
   198 * Isar: 'print_facts' prints all local facts of the current context,
   199 both named and unnamed ones.
   200 
   201 * Isar: 'def' now admits simultaneous definitions, e.g.:
   202 
   203   def x == "t" and y == "u"
   204 
   205 * Isar: added command 'unfolding', which is structurally similar to
   206 'using', but affects both the goal state and facts by unfolding given
   207 rewrite rules.  Thus many occurrences of the 'unfold' method or
   208 'unfolded' attribute may be replaced by first-class proof text.
   209 
   210 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   211 and command 'unfolding' now all support object-level equalities
   212 (potentially conditional).  The underlying notion of rewrite rule is
   213 analogous to the 'rule_format' attribute, but *not* that of the
   214 Simplifier (which is usually more generous).
   215 
   216 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   217 method expression within a sandbox consisting of the first N
   218 sub-goals, which need to exist.  For example, ``simp_all [3]''
   219 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   220 simplifies all new goals that emerge from applying rule foo to the
   221 originally first one.
   222 
   223 * Isar: schematic goals are no longer restricted to higher-order
   224 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   225 expected.
   226 
   227 * Isar: the conclusion of a long theorem statement is now either
   228 'shows' (a simultaneous conjunction, as before), or 'obtains'
   229 (essentially a disjunction of cases with local parameters and
   230 assumptions).  The latter allows to express general elimination rules
   231 adequately; in this notation common elimination rules look like this:
   232 
   233   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   234     assumes "EX x. P x"
   235     obtains x where "P x"
   236 
   237   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   238     assumes "A & B"
   239     obtains A and B
   240 
   241   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   242     assumes "A | B"
   243     obtains
   244       A
   245     | B
   246 
   247 The subsequent classical rules even refer to the formal "thesis"
   248 explicitly:
   249 
   250   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   251     obtains "~ thesis"
   252 
   253   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   254     obtains "thesis ==> something"
   255 
   256 The actual proof of an 'obtains' statement is analogous to that of the
   257 Isar proof element 'obtain', only that there may be several cases.
   258 Optional case names may be specified in parentheses; these will be
   259 available both in the present proof and as annotations in the
   260 resulting rule, for later use with the 'cases' method (cf. attribute
   261 case_names).
   262 
   263 * Isar: the assumptions of a long theorem statement are available as
   264 "assms" fact in the proof context.  This is more appropriate than the
   265 (historical) "prems", which refers to all assumptions of the current
   266 context, including those from the target locale, proof body etc.
   267 
   268 * Isar: 'print_statement' prints theorems from the current theory or
   269 proof context in long statement form, according to the syntax of a
   270 top-level lemma.
   271 
   272 * Isar: 'obtain' takes an optional case name for the local context
   273 introduction rule (default "that").
   274 
   275 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   276 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   277 to occur.
   278 
   279 * Pure: syntax "CONST name" produces a fully internalized constant
   280 according to the current context.  This is particularly useful for
   281 syntax translations that should refer to internal constant
   282 representations independently of name spaces.
   283 
   284 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   285 instead of "FOO ". This allows multiple binder declarations to coexist
   286 in the same context.  INCOMPATIBILITY.
   287 
   288 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   289 primitive that also works in a locale context (both for constants and
   290 fixed variables).  Type declaration and internal syntactic
   291 representation of given constants retrieved from the context.
   292 
   293 * Isar/locales: new derived specification elements 'axiomatization',
   294 'definition', 'abbreviation', which support type-inference, admit
   295 object-level specifications (equality, equivalence).  See also the
   296 isar-ref manual.  Examples:
   297 
   298   axiomatization
   299     eq  (infix "===" 50) where
   300     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   301 
   302   definition "f x y = x + y + 1"
   303   definition g where "g x = f x x"
   304 
   305   abbreviation
   306     neq  (infix "=!=" 50) where
   307     "x =!= y == ~ (x === y)"
   308 
   309 These specifications may be also used in a locale context.  Then the
   310 constants being introduced depend on certain fixed parameters, and the
   311 constant name is qualified by the locale base name.  An internal
   312 abbreviation takes care for convenient input and output, making the
   313 parameters implicit and using the original short name.  See also
   314 HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   315 entities from a monomorphic theory.
   316 
   317 Presently, abbreviations are only available 'in' a target locale, but
   318 not inherited by general import expressions.  Also note that
   319 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   320 'translations' in common applications.
   321 
   322 Concrete syntax is attached to specified constants in internal form,
   323 independently of name spaces.  The parse tree representation is
   324 slightly different -- use 'notation' instead of raw 'syntax', and
   325 'translations' with explicit "CONST" markup to accommodate this.
   326 
   327 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   328 the current context.  Print mode "no_abbrevs" prevents inversion of
   329 abbreviations on output.
   330 
   331 * Isar/locales: improved parameter handling:
   332 - use of locales "var" and "struct" no longer necessary;
   333 - parameter renamings are no longer required to be injective.
   334   This enables, for example, to define a locale for endomorphisms thus:
   335   locale endom = homom mult mult h.
   336 
   337 * Isar/locales: changed the way locales with predicates are defined.
   338 Instead of accumulating the specification, the imported expression is
   339 now an interpretation.  INCOMPATIBILITY: different normal form of
   340 locale expressions.  In particular, in interpretations of locales with
   341 predicates, goals repesenting already interpreted fragments are not
   342 removed automatically.  Use methods `intro_locales' and
   343 `unfold_locales'; see below.
   344 
   345 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   346 provide backward reasoning on locales predicates.  The methods are
   347 aware of interpretations and discharge corresponding goals.
   348 `intro_locales' is less aggressive then `unfold_locales' and does not
   349 unfold predicates to assumptions.
   350 
   351 * Isar/locales: the order in which locale fragments are accumulated
   352 has changed.  This enables to override declarations from fragments due
   353 to interpretations -- for example, unwanted simp rules.
   354 
   355 * Provers/induct: improved internal context management to support
   356 local fixes and defines on-the-fly.  Thus explicit meta-level
   357 connectives !! and ==> are rarely required anymore in inductive goals
   358 (using object-logic connectives for this purpose has been long
   359 obsolete anyway).  The subsequent proof patterns illustrate advanced
   360 techniques of natural induction; general datatypes and inductive sets
   361 work analogously (see also src/HOL/Lambda for realistic examples).
   362 
   363 (1) This is how to ``strengthen'' an inductive goal wrt. certain
   364 parameters:
   365 
   366   lemma
   367     fixes n :: nat and x :: 'a
   368     assumes a: "A n x"
   369     shows "P n x"
   370     using a                     -- {* make induct insert fact a *}
   371   proof (induct n arbitrary: x) -- {* generalize goal to "!!x. A n x ==> P n x" *}
   372     case 0
   373     show ?case sorry
   374   next
   375     case (Suc n)
   376     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
   377     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
   378     show ?case sorry
   379   qed
   380 
   381 (2) This is how to perform induction over ``expressions of a certain
   382 form'', using a locally defined inductive parameter n == "a x"
   383 together with strengthening (the latter is usually required to get
   384 sufficiently flexible induction hypotheses):
   385 
   386   lemma
   387     fixes a :: "'a => nat"
   388     assumes a: "A (a x)"
   389     shows "P (a x)"
   390     using a
   391   proof (induct n == "a x" arbitrary: x)
   392     ...
   393 
   394 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   395 particular technique.
   396 
   397 (3) This is how to perform existential reasoning ('obtains' or
   398 'obtain') by induction, while avoiding explicit object-logic
   399 encodings:
   400 
   401   lemma
   402     fixes n :: nat
   403     obtains x :: 'a where "P n x" and "Q n x"
   404   proof (induct n arbitrary: thesis)
   405     case 0
   406     obtain x where "P 0 x" and "Q 0 x" sorry
   407     then show thesis by (rule 0)
   408   next
   409     case (Suc n)
   410     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   411     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   412     then show thesis by (rule Suc.prems)
   413   qed
   414 
   415 Here the 'arbitrary: thesis' specification essentially modifies the
   416 scope of the formal thesis parameter, in order to the get the whole
   417 existence statement through the induction as expected.
   418 
   419 * Provers/induct: mutual induction rules are now specified as a list
   420 of rule sharing the same induction cases.  HOL packages usually
   421 provide foo_bar.inducts for mutually defined items foo and bar
   422 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   423 specify mutual induction rules differently, i.e. like this:
   424 
   425   (induct rule: foo_bar.inducts)
   426   (induct set: foo bar)
   427   (induct type: foo bar)
   428 
   429 The ML function ProjectRule.projections turns old-style rules into the
   430 new format.
   431 
   432 * Provers/induct: improved handling of simultaneous goals.  Instead of
   433 introducing object-level conjunction, the statement is now split into
   434 several conclusions, while the corresponding symbolic cases are
   435 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   436 explicitly.  For example:
   437 
   438   lemma
   439     fixes n :: nat
   440     shows "P n" and "Q n"
   441   proof (induct n)
   442     case 0 case 1
   443     show "P 0" sorry
   444   next
   445     case 0 case 2
   446     show "Q 0" sorry
   447   next
   448     case (Suc n) case 1
   449     note `P n` and `Q n`
   450     show "P (Suc n)" sorry
   451   next
   452     case (Suc n) case 2
   453     note `P n` and `Q n`
   454     show "Q (Suc n)" sorry
   455   qed
   456 
   457 The split into subcases may be deferred as follows -- this is
   458 particularly relevant for goal statements with local premises.
   459 
   460   lemma
   461     fixes n :: nat
   462     shows "A n ==> P n" and "B n ==> Q n"
   463   proof (induct n)
   464     case 0
   465     {
   466       case 1
   467       note `A 0`
   468       show "P 0" sorry
   469     next
   470       case 2
   471       note `B 0`
   472       show "Q 0" sorry
   473     }
   474   next
   475     case (Suc n)
   476     note `A n ==> P n` and `B n ==> Q n`
   477     {
   478       case 1
   479       note `A (Suc n)`
   480       show "P (Suc n)" sorry
   481     next
   482       case 2
   483       note `B (Suc n)`
   484       show "Q (Suc n)" sorry
   485     }
   486   qed
   487 
   488 If simultaneous goals are to be used with mutual rules, the statement
   489 needs to be structured carefully as a two-level conjunction, using
   490 lists of propositions separated by 'and':
   491 
   492   lemma
   493     shows "a : A ==> P1 a"
   494           "a : A ==> P2 a"
   495       and "b : B ==> Q1 b"
   496           "b : B ==> Q2 b"
   497           "b : B ==> Q3 b"
   498   proof (induct set: A B)
   499 
   500 * Provers/induct: support coinduction as well.  See
   501 src/HOL/Library/Coinductive_List.thy for various examples.
   502 
   503 * Attribute "symmetric" produces result with standardized schematic
   504 variables (index 0).  Potential INCOMPATIBILITY.
   505 
   506 * Simplifier: by default the simplifier trace only shows top level
   507 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   508 default. Thus there is less danger of being flooded by the trace. The
   509 trace indicates where parts have been suppressed.
   510   
   511 * Provers/classical: removed obsolete classical version of elim_format
   512 attribute; classical elim/dest rules are now treated uniformly when
   513 manipulating the claset.
   514 
   515 * Provers/classical: stricter checks to ensure that supplied intro,
   516 dest and elim rules are well-formed; dest and elim rules must have at
   517 least one premise.
   518 
   519 * Provers/classical: attributes dest/elim/intro take an optional
   520 weight argument for the rule (just as the Pure versions).  Weights are
   521 ignored by automated tools, but determine the search order of single
   522 rule steps.
   523 
   524 * Syntax: input syntax now supports dummy variable binding "%_. b",
   525 where the body does not mention the bound variable.  Note that dummy
   526 patterns implicitly depend on their context of bounds, which makes
   527 "{_. _}" match any set comprehension as expected.  Potential
   528 INCOMPATIBILITY -- parse translations need to cope with syntactic
   529 constant "_idtdummy" in the binding position.
   530 
   531 * Syntax: removed obsolete syntactic constant "_K" and its associated
   532 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   533 for example "A -> B" => "Pi A (%_. B)".
   534 
   535 * Pure: 'class_deps' command visualizes the subclass relation, using
   536 the graph browser tool.
   537 
   538 * Pure: 'print_theory' now suppresses entities with internal name
   539 (trailing "_") by default; use '!' option for full details.
   540 
   541 
   542 *** HOL ***
   543 
   544 * Method "metis" proves goals by applying the Metis general-purpose resolution prover.
   545   Examples are in the directory MetisExamples.
   546   
   547 * Command "sledgehammer" invokes external automatic theorem provers as background processes.
   548   It generates calls to the "metis" method if successful. These can be pasted into the proof.
   549   Users do not have to wait for the automatic provers to return.
   550 
   551 * IntDef: The constant "int :: nat => int" has been removed; now "int"
   552   is an abbreviation for "of_nat :: nat => int". The simplification rules
   553   for "of_nat" have been changed to work like "int" did previously.
   554   (potential INCOMPATIBILITY)
   555   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
   556   - of_nat_diff and of_nat_mult are no longer default simp rules
   557 
   558 * Method "algebra" solves polynomial equations over (semi)rings using
   559   Groebner bases. The (semi)ring structure is defined by locales and
   560   the tool setup depends on that generic context. Installing the
   561   method for a specific type involves instantiating the locale and
   562   possibly adding declarations for computation on the coefficients.
   563   The method is already instantiated for natural numbers and for the
   564   axiomatic class of idoms with numerals.  See also the paper by
   565   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   566   underlying this architecture of context-aware proof-tools.
   567 
   568 * constant "List.op @" now named "List.append".  Use ML antiquotations
   569 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   570 possible incompatibilities when working on ML level.
   571 
   572 * Constant renames due to introduction of canonical name prefixing for
   573   class package:
   574 
   575     HOL.abs ~> HOL.minus_class.abs
   576     HOL.divide ~> HOL.divide_class.divide
   577     Nat.power ~> Nat.power_class.power
   578     Nat.size ~> Nat.size_class.size
   579     Numeral.number_of ~> Numeral.number_class.number_of
   580     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   581 
   582 * Rudimentary class target mechanism involves constant renames:
   583 
   584     Orderings.min ~> Orderings.ord_class.min
   585     Orderings.max ~> Orderings.ord_class.max
   586     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   587 
   588 * case expressions and primrec: missing cases now mapped to "undefined"
   589 instead of "arbitrary"
   590 
   591 * new constant "undefined" with axiom "undefined x = undefined"
   592 
   593 * new class "default" with associated constant "default"
   594 
   595 * new function listsum :: 'a list => 'a for arbitrary monoids.
   596   Special syntax: "SUM x <- xs. f x" (and latex variants)
   597 
   598 * new (input only) syntax for Haskell-like list comprehension, eg
   599   [(x,y). x <- xs, y <- ys, x ~= y]
   600   For details see List.thy.
   601 
   602 * The special syntax for function "filter" has changed from [x : xs. P] to
   603   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   604   and for uniformity. INCOMPATIBILITY
   605 
   606 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   607     when generating code.
   608 
   609 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   610     when generating code.
   611 
   612 * Library/Commutative_Ring.thy: switched from recdef to function package;
   613     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   614 
   615 * Some steps towards more uniform lattice theory development in HOL.
   616 
   617     constants "meet" and "join" now named "inf" and "sup"
   618     constant "Meet" now named "Inf"
   619 
   620     classes "meet_semilorder" and "join_semilorder" now named
   621       "lower_semilattice" and "upper_semilattice"
   622     class "lorder" now named "lattice"
   623     class "comp_lat" now named "complete_lattice"
   624 
   625     Instantiation of lattice classes allows explicit definitions
   626     for "inf" and "sup" operations.
   627 
   628   INCOMPATIBILITY.  Theorem renames:
   629 
   630     meet_left_le            ~> inf_le1
   631     meet_right_le           ~> inf_le2
   632     join_left_le            ~> sup_ge1
   633     join_right_le           ~> sup_ge2
   634     meet_join_le            ~> inf_sup_ord
   635     le_meetI                ~> le_infI
   636     join_leI                ~> le_supI
   637     le_meet                 ~> le_inf_iff
   638     le_join                 ~> ge_sup_conv
   639     meet_idempotent         ~> inf_idem
   640     join_idempotent         ~> sup_idem
   641     meet_comm               ~> inf_commute
   642     join_comm               ~> sup_commute
   643     meet_leI1               ~> le_infI1
   644     meet_leI2               ~> le_infI2
   645     le_joinI1               ~> le_supI1
   646     le_joinI2               ~> le_supI2
   647     meet_assoc              ~> inf_assoc
   648     join_assoc              ~> sup_assoc
   649     meet_left_comm          ~> inf_left_commute
   650     meet_left_idempotent    ~> inf_left_idem
   651     join_left_comm          ~> sup_left_commute
   652     join_left_idempotent    ~> sup_left_idem
   653     meet_aci                ~> inf_aci
   654     join_aci                ~> sup_aci
   655     le_def_meet             ~> le_iff_inf
   656     le_def_join             ~> le_iff_sup
   657     join_absorp2            ~> sup_absorb2
   658     join_absorp1            ~> sup_absorb1
   659     meet_absorp1            ~> inf_absorb1
   660     meet_absorp2            ~> inf_absorb2
   661     meet_join_absorp        ~> inf_sup_absorb
   662     join_meet_absorp        ~> sup_inf_absorb
   663     distrib_join_le         ~> distrib_sup_le
   664     distrib_meet_le         ~> distrib_inf_le
   665 
   666     add_meet_distrib_left   ~> add_inf_distrib_left
   667     add_join_distrib_left   ~> add_sup_distrib_left
   668     is_join_neg_meet        ~> is_join_neg_inf
   669     is_meet_neg_join        ~> is_meet_neg_sup
   670     add_meet_distrib_right  ~> add_inf_distrib_right
   671     add_join_distrib_right  ~> add_sup_distrib_right
   672     add_meet_join_distribs  ~> add_sup_inf_distribs
   673     join_eq_neg_meet        ~> sup_eq_neg_inf
   674     meet_eq_neg_join        ~> inf_eq_neg_sup
   675     add_eq_meet_join        ~> add_eq_inf_sup
   676     meet_0_imp_0            ~> inf_0_imp_0
   677     join_0_imp_0            ~> sup_0_imp_0
   678     meet_0_eq_0             ~> inf_0_eq_0
   679     join_0_eq_0             ~> sup_0_eq_0
   680     neg_meet_eq_join        ~> neg_inf_eq_sup
   681     neg_join_eq_meet        ~> neg_sup_eq_inf
   682     join_eq_if              ~> sup_eq_if
   683 
   684     mono_meet               ~> mono_inf
   685     mono_join               ~> mono_sup
   686     meet_bool_eq            ~> inf_bool_eq
   687     join_bool_eq            ~> sup_bool_eq
   688     meet_fun_eq             ~> inf_fun_eq
   689     join_fun_eq             ~> sup_fun_eq
   690     meet_set_eq             ~> inf_set_eq
   691     join_set_eq             ~> sup_set_eq
   692     meet1_iff               ~> inf1_iff
   693     meet2_iff               ~> inf2_iff
   694     meet1I                  ~> inf1I
   695     meet2I                  ~> inf2I
   696     meet1D1                 ~> inf1D1
   697     meet2D1                 ~> inf2D1
   698     meet1D2                 ~> inf1D2
   699     meet2D2                 ~> inf2D2
   700     meet1E                  ~> inf1E
   701     meet2E                  ~> inf2E
   702     join1_iff               ~> sup1_iff
   703     join2_iff               ~> sup2_iff
   704     join1I1                 ~> sup1I1
   705     join2I1                 ~> sup2I1
   706     join1I1                 ~> sup1I1
   707     join2I2                 ~> sup1I2
   708     join1CI                 ~> sup1CI
   709     join2CI                 ~> sup2CI
   710     join1E                  ~> sup1E
   711     join2E                  ~> sup2E
   712 
   713     is_meet_Meet            ~> is_meet_Inf
   714     Meet_bool_def           ~> Inf_bool_def
   715     Meet_fun_def            ~> Inf_fun_def
   716     Meet_greatest           ~> Inf_greatest
   717     Meet_lower              ~> Inf_lower
   718     Meet_set_def            ~> Inf_set_def
   719 
   720     listsp_meetI            ~> listsp_infI
   721     listsp_meet_eq          ~> listsp_inf_eq
   722 
   723     meet_min                ~> inf_min
   724     join_max                ~> sup_max
   725 
   726 * Classes "order" and "linorder": facts "refl", "trans" and
   727 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   728 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   729 
   730 * Classes "order" and "linorder": 
   731 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   732 proofs changed.
   733 
   734 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   735 INCOMPATIBILITY.
   736 
   737 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   738 INCOMPATIBILITY.
   739 
   740 * Added syntactic class "size"; overloaded constant "size" now has
   741 type "'a::size ==> bool"
   742 
   743 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   744 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   745 
   746 * Added method "lexicographic_order" automatically synthesizes
   747 termination relations as lexicographic combinations of size measures
   748 -- 'function' package.
   749 
   750 * HOL/records: generalised field-update to take a function on the
   751 field rather than the new value: r(|A := x|) is translated to A_update
   752 (K x) r The K-combinator that is internally used is called K_record.
   753 INCOMPATIBILITY: Usage of the plain update functions has to be
   754 adapted.
   755  
   756 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   757 0 * x = 0, which are required for a semiring.  Richer structures do
   758 not inherit from semiring_0 anymore, because this property is a
   759 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   760 semiring_0, there is more to prove, but this is mostly trivial.
   761 
   762 * axclass "recpower" was generalized to arbitrary monoids, not just
   763 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   764 commutativity or a semiring property, add the corresponding classes.
   765 
   766 * Unified locale partial_order with class definition (cf. theory
   767 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   768 
   769 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   770 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   771 Isar level, use abbreviations instead.
   772 
   773 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   774 rarely occuring name references (e.g. ``List.op mem.simps'') require
   775 renaming (e.g. ``List.memberl.simps'').
   776 
   777 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   778 INCOMPATIBILITY.
   779 
   780 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   781 
   782 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   783 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   784 significant changes for setting up numeral syntax for types:
   785 
   786   - new constants Numeral.pred and Numeral.succ instead
   787       of former Numeral.bin_pred and Numeral.bin_succ.
   788   - Use integer operations instead of bin_add, bin_mult and so on.
   789   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   790   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   791 
   792 See HOL/Integ/IntArith.thy for an example setup.
   793 
   794 * New top level command 'normal_form' computes the normal form of a
   795 term that may contain free variables. For example ``normal_form
   796 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   797 suitable for heavy-duty computations because the functions are
   798 compiled to ML first.
   799 
   800 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   801 25 like -->); output depends on the "iff" print_mode, the default is
   802 "A = B" (with priority 50).
   803 
   804 * Renamed constants in HOL.thy and Orderings.thy:
   805     op +   ~> HOL.plus_class.plus
   806     op -   ~> HOL.minus_class.minus
   807     uminus ~> HOL.minus_class.uminus
   808     op *   ~> HOL.times_class.times
   809     op <   ~> Orderings.ord_class.less
   810     op <=  ~> Orderings.ord_class.less_eq
   811 
   812 Adaptions may be required in the following cases:
   813 
   814 a) User-defined constants using any of the names "plus", "minus", "times",
   815 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   816 may go wrong.
   817 INCOMPATIBILITY: use more specific names.
   818 
   819 b) Variables named "plus", "minus", "times", "less", "less_eq"
   820 INCOMPATIBILITY: use more specific names.
   821 
   822 c) Permutative equations (e.g. "a + b = b + a")
   823 Since the change of names also changes the order of terms, permutative
   824 rewrite rules may get applied in a different order. Experience shows that
   825 this is rarely the case (only two adaptions in the whole Isabelle
   826 distribution).
   827 INCOMPATIBILITY: rewrite proofs
   828 
   829 d) ML code directly refering to constant names
   830 This in general only affects hand-written proof tactics, simprocs and so on.
   831 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   832 of const_name ML antiquotations.
   833 
   834 * Relations less (<) and less_eq (<=) are also available on type bool.
   835 Modified syntax to disallow nesting without explicit parentheses,
   836 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   837 
   838 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   839 
   840 * Relation composition operator "op O" now has precedence 75 and binds
   841 stronger than union and intersection. INCOMPATIBILITY.
   842 
   843 * The old set interval syntax "{m..n(}" (and relatives) has been
   844 removed.  Use "{m..<n}" (and relatives) instead.
   845 
   846 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   847 "t = s" to False (by simproc "neq_simproc").  For backward
   848 compatibility this can be disabled by ML "reset use_neq_simproc".
   849 
   850 * "m dvd n" where m and n are numbers is evaluated to True/False by
   851 simp.
   852 
   853 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   854 
   855 * Theorem setsum_mult renamed to setsum_right_distrib.
   856 
   857 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   858 ``rule'' method.
   859 
   860 * Reimplemented methods ``sat'' and ``satx'', with several
   861 improvements: goals no longer need to be stated as "<prems> ==>
   862 False", equivalences (i.e. "=" on type bool) are handled, variable
   863 names of the form "lit_<n>" are no longer reserved, significant
   864 speedup.
   865 
   866 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   867 zChaff is still supported as well.
   868 
   869 * 'inductive' and 'datatype': provide projections of mutual rules,
   870 bundled as foo_bar.inducts;
   871 
   872 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   873 Library.
   874 
   875 * Library: moved theory Accessible_Part to main HOL.
   876 
   877 * Library: added theory Coinductive_List of potentially infinite lists
   878 as greatest fixed-point.
   879 
   880 * Library: added theory AssocList which implements (finite) maps as
   881 association lists.
   882 
   883 * Added proof method ``evaluation'' for efficiently solving a goal
   884 (i.e. a boolean expression) by compiling it to ML. The goal is
   885 "proved" (via an oracle) if it evaluates to True.
   886 
   887 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   888 also when invoked by the simplifier.  This results in the simplifier
   889 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   890 fast_arith_split_limit to 0 to obtain the old behavior.
   891 
   892 * Support for hex (0x20) and binary (0b1001) numerals.
   893 
   894 * New method: reify eqs (t), where eqs are equations for an
   895 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   896 parameter, computes a term s::'b and a list xs::'a list and proves the
   897 theorem I xs s = t. This is also known as reification or quoting. The
   898 resulting theorem is applied to the subgoal to substitute t with I xs
   899 s.  If t is omitted, the subgoal itself is reified.
   900 
   901 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   902 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   903 where f is supposed to be a computable function (in the sense of code
   904 generattion). The method uses reify to compute s and xs as above then
   905 applies corr_thm and uses normalization by evaluation to "prove" f s =
   906 r and finally gets the theorem t = r, which is again applied to the
   907 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   908 
   909 * Reflection: Automatic refification now handels binding, an example
   910 is available in HOL/ex/ReflectionEx.thy
   911 
   912 
   913 *** HOL-Algebra ***
   914 
   915 * Formalisation of ideals and the quotient construction over rings.
   916 
   917 * Order and lattice theory no longer based on records.
   918 INCOMPATIBILITY.
   919 
   920 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   921 greatest_closed.  INCOMPATIBILITY.
   922 
   923 * Method algebra is now set up via an attribute.  For examples see
   924 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   925 of algebraic structures.
   926 
   927 * Renamed theory CRing to Ring.
   928 
   929 
   930 *** HOL-Complex ***
   931 
   932 * Theory Real: new method ferrack implements quantifier elimination
   933 for linear arithmetic over the reals. The quantifier elimination
   934 feature is used only for decision, for compatibility with arith. This
   935 means a goal is either solved or left unchanged, no simplification.
   936 
   937 * Hyperreal: Functions root and sqrt are now defined on negative real
   938 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   939 Nonnegativity side conditions have been removed from many lemmas, so
   940 that more subgoals may now be solved by simplification; potential
   941 INCOMPATIBILITY.
   942 
   943 * Real: New axiomatic classes formalize real normed vector spaces and
   944 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   945 and norm :: 'a => real.
   946 
   947 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   948 from reals into other types. The overloaded constant Reals :: 'a set
   949 is now defined as range of_real; potential INCOMPATIBILITY.
   950 
   951 * Real: ML code generation is supported now and hence also quickcheck.
   952 Reals are implemented as arbitrary precision rationals.
   953 
   954 * Hyperreal: Several constants that previously worked only for the
   955 reals have been generalized, so they now work over arbitrary vector
   956 spaces. Type annotations may need to be added in some cases; potential
   957 INCOMPATIBILITY.
   958 
   959   Infinitesimal  :: ('a::real_normed_vector) star set
   960   HFinite        :: ('a::real_normed_vector) star set
   961   HInfinite      :: ('a::real_normed_vector) star set
   962   approx         :: ('a::real_normed_vector) star => 'a star => bool
   963   monad          :: ('a::real_normed_vector) star => 'a star set
   964   galaxy         :: ('a::real_normed_vector) star => 'a star set
   965   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   966   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   967   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   968   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   969   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   970   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   971   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   972   sgn            :: 'a::real_normed_vector => 'a
   973   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   974 
   975 * Complex: Some complex-specific constants are now abbreviations for
   976 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   977 hnorm.  Other constants have been entirely removed in favor of the
   978 polymorphic versions (INCOMPATIBILITY):
   979 
   980   approx        <-- capprox
   981   HFinite       <-- CFinite
   982   HInfinite     <-- CInfinite
   983   Infinitesimal <-- CInfinitesimal
   984   monad         <-- cmonad
   985   galaxy        <-- cgalaxy
   986   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   987   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   988   (ns)deriv     <-- (ns)cderiv
   989 
   990 
   991 *** ML ***
   992 
   993 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
   994 
   995 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   996 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   997 init only required for impure data.  INCOMPATIBILITY: empty really
   998 need to be empty (no dependencies on theory content!)
   999 
  1000 * ML within Isar: antiquotations allow to embed statically-checked
  1001 formal entities in the source, referring to the context available at
  1002 compile-time.  For example:
  1003 
  1004 ML {* @{typ "'a => 'b"} *}
  1005 ML {* @{term "%x. x"} *}
  1006 ML {* @{prop "x == y"} *}
  1007 ML {* @{ctyp "'a => 'b"} *}
  1008 ML {* @{cterm "%x. x"} *}
  1009 ML {* @{cprop "x == y"} *}
  1010 ML {* @{thm asm_rl} *}
  1011 ML {* @{thms asm_rl} *}
  1012 ML {* @{const_name c} *}
  1013 ML {* @{const_syntax c} *}
  1014 ML {* @{context} *}
  1015 ML {* @{theory} *}
  1016 ML {* @{theory Pure} *}
  1017 ML {* @{simpset} *}
  1018 ML {* @{claset} *}
  1019 ML {* @{clasimpset} *}
  1020 
  1021 The same works for sources being ``used'' within an Isar context.
  1022 
  1023 * ML in Isar: improved error reporting; extra verbosity with
  1024 Toplevel.debug enabled.
  1025 
  1026 * Pure/library:
  1027 
  1028   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1029   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1030 
  1031 The semantics of "burrow" is: "take a function with *simulatanously*
  1032 transforms a list of value, and apply it *simulatanously* to a list of
  1033 list of values of the appropriate type". Compare this with "map" which
  1034 would *not* apply its argument function simulatanously but in
  1035 sequence; "fold_burrow" has an additional context.
  1036 
  1037 * Pure/library: functions map2 and fold2 with curried syntax for
  1038 simultanous mapping and folding:
  1039 
  1040     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1041     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1042 
  1043 * Pure/library: indexed lists - some functions in the Isabelle library
  1044 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1045 given more convenient names and signatures reminiscent of similar
  1046 functions for alists, tables, etc:
  1047 
  1048   val nth: 'a list -> int -> 'a 
  1049   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1050   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1051 
  1052 Note that fold_index starts counting at index 0, not 1 like foldln
  1053 used to.
  1054 
  1055 * Pure/library: added general ``divide_and_conquer'' combinator on
  1056 lists.
  1057 
  1058 * Pure/General/table.ML: the join operations now works via exceptions
  1059 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1060 admits slightly more efficient complex applications.
  1061 
  1062 * Pure: datatype Context.generic joins theory/Proof.context and
  1063 provides some facilities for code that works in either kind of
  1064 context, notably GenericDataFun for uniform theory and proof data.
  1065 
  1066 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1067 use Context.generic instead of just theory.
  1068 
  1069 * Pure: simplified internal attribute type, which is now always
  1070 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1071 vs. local (Proof.context) attributes have been discontinued, while
  1072 minimizing code duplication.  Thm.rule_attribute and
  1073 Thm.declaration_attribute build canonical attributes; see also
  1074 structure Context for further operations on Context.generic, notably
  1075 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1076 declarations and definitions.
  1077 
  1078 * Pure/kernel: consts certification ignores sort constraints given in
  1079 signature declarations.  (This information is not relevant to the
  1080 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1081 potential INCOMPATIBILITY.
  1082 
  1083 * Pure: axiomatic type classes are now purely definitional, with
  1084 explicit proofs of class axioms and super class relations performed
  1085 internally.  See Pure/axclass.ML for the main internal interfaces --
  1086 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1087 AxClass.axiomatize_class/classrel/arity supercede
  1088 Sign.add_classes/classrel/arities.
  1089 
  1090 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1091 global/local versions on theory vs. Proof.context have been
  1092 discontinued; Attrib.syntax and Method.syntax have been adapted
  1093 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1094 attributes, methods, etc.
  1095 
  1096 * Pure: several functions of signature "... -> theory -> theory * ..."
  1097 have been reoriented to "... -> theory -> ... * theory" in order to
  1098 allow natural usage in combination with the ||>, ||>>, |-> and
  1099 fold_map combinators.
  1100 
  1101 * Pure: official theorem names (closed derivations) and additional
  1102 comments (tags) are now strictly separate.  Name hints -- which are
  1103 maintained as tags -- may be attached any time without affecting the
  1104 derivation.
  1105 
  1106 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1107 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1108 achieve the old behaviour.
  1109 
  1110 * Pure: the "Goal" constant is now called "prop", supporting a
  1111 slightly more general idea of ``protecting'' meta-level rule
  1112 statements.
  1113 
  1114 * Pure: Logic.(un)varify only works in a global context, which is now
  1115 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1116 Logic.legacy_(un)varify as temporary workaround.
  1117 
  1118 * Pure: structure Name provides scalable operations for generating
  1119 internal variable names, notably Name.variants etc.  This replaces
  1120 some popular functions from term.ML:
  1121 
  1122   Term.variant		->  Name.variant
  1123   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1124   Term.invent_names	->  Name.invent_list
  1125 
  1126 Note that low-level renaming rarely occurs in new code -- operations
  1127 from structure Variable are used instead (see below).
  1128 
  1129 * Pure: structure Variable provides fundamental operations for proper
  1130 treatment of fixed/schematic variables in a context.  For example,
  1131 Variable.import introduces fixes for schematics of given facts and
  1132 Variable.export reverses the effect (up to renaming) -- this replaces
  1133 various freeze_thaw operations.
  1134 
  1135 * Pure: structure Goal provides simple interfaces for
  1136 init/conclude/finish and tactical prove operations (replacing former
  1137 Tactic.prove).  Goal.prove is the canonical way to prove results
  1138 within a given context; Goal.prove_global is a degraded version for
  1139 theory level goals, including a global Drule.standard.  Note that
  1140 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1141 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1142 in a locale context).
  1143 
  1144 * Isar: simplified treatment of user-level errors, using exception
  1145 ERROR of string uniformly.  Function error now merely raises ERROR,
  1146 without any side effect on output channels.  The Isar toplevel takes
  1147 care of proper display of ERROR exceptions.  ML code may use plain
  1148 handle/can/try; cat_error may be used to concatenate errors like this:
  1149 
  1150   ... handle ERROR msg => cat_error msg "..."
  1151 
  1152 Toplevel ML code (run directly or through the Isar toplevel) may be
  1153 embedded into the Isar toplevel with exception display/debug like
  1154 this:
  1155 
  1156   Isar.toplevel (fn () => ...)
  1157 
  1158 INCOMPATIBILITY, removed special transform_error facilities, removed
  1159 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1160 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1161 -- use plain ERROR instead.
  1162 
  1163 * Isar: theory setup now has type (theory -> theory), instead of a
  1164 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1165 
  1166 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1167 subject to ProofContext.debug/verbose flags.
  1168 
  1169 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1170 theory before entering a proof state.  Transactions now always see a
  1171 quasi-functional intermediate checkpoint, both in interactive and
  1172 batch mode.
  1173 
  1174 * Simplifier: the simpset of a running simplification process now
  1175 contains a proof context (cf. Simplifier.the_context), which is the
  1176 very context that the initial simpset has been retrieved from (by
  1177 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1178 (solver, looper etc.) may depend on arbitrary proof data.
  1179 
  1180 * Simplifier.inherit_context inherits the proof context (plus the
  1181 local bounds) of the current simplification process; any simproc
  1182 etc. that calls the Simplifier recursively should do this!  Removed
  1183 former Simplifier.inherit_bounds, which is already included here --
  1184 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1185 specify an explicit context using Simplifier.context/theory_context.
  1186 
  1187 * Simplifier/Classical Reasoner: more abstract interfaces
  1188 change_simpset/claset for modifying the simpset/claset reference of a
  1189 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1190 INCOMPATIBILITY.
  1191 
  1192 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1193 "Trueprop" etc.
  1194 
  1195 
  1196 *** System ***
  1197 
  1198 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1199 locations -- now includes the Isabelle version identifier as well.
  1200 This simplifies use of multiple Isabelle installations.
  1201 
  1202 * isabelle-process: option -S (secure mode) disables some critical
  1203 operations, notably runtime compilation and evaluation of ML source
  1204 code.
  1205 
  1206 
  1207 New in Isabelle2005 (October 2005)
  1208 ----------------------------------
  1209 
  1210 *** General ***
  1211 
  1212 * Theory headers: the new header syntax for Isar theories is
  1213 
  1214   theory <name>
  1215   imports <theory1> ... <theoryN>
  1216   uses <file1> ... <fileM>
  1217   begin
  1218 
  1219 where the 'uses' part is optional.  The previous syntax
  1220 
  1221   theory <name> = <theory1> + ... + <theoryN>:
  1222 
  1223 will disappear in the next release.  Use isatool fixheaders to convert
  1224 existing theory files.  Note that there is no change in ancient
  1225 non-Isar theories now, but these will disappear soon.
  1226 
  1227 * Theory loader: parent theories can now also be referred to via
  1228 relative and absolute paths.
  1229 
  1230 * Command 'find_theorems' searches for a list of criteria instead of a
  1231 list of constants. Known criteria are: intro, elim, dest, name:string,
  1232 simp:term, and any term. Criteria can be preceded by '-' to select
  1233 theorems that do not match. Intro, elim, dest select theorems that
  1234 match the current goal, name:s selects theorems whose fully qualified
  1235 name contain s, and simp:term selects all simplification rules whose
  1236 lhs match term.  Any other term is interpreted as pattern and selects
  1237 all theorems matching the pattern. Available in ProofGeneral under
  1238 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1239 
  1240   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1241 
  1242 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1243 matching the current goal as introduction rule and not having "HOL."
  1244 in their name (i.e. not being defined in theory HOL).
  1245 
  1246 * Command 'thms_containing' has been discontinued in favour of
  1247 'find_theorems'; INCOMPATIBILITY.
  1248 
  1249 * Communication with Proof General is now 8bit clean, which means that
  1250 Unicode text in UTF-8 encoding may be used within theory texts (both
  1251 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1252 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1253 
  1254   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1255   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1256 
  1257 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1258 Classical Reasoner.  Typical big applications run around 2 times
  1259 faster.
  1260 
  1261 
  1262 *** Document preparation ***
  1263 
  1264 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1265 of raw sources.  Only those symbols that do not require additional
  1266 LaTeX packages (depending on comments in isabellesym.sty) are
  1267 displayed properly, everything else is left verbatim.  isatool display
  1268 and isatool print are used as front ends (these are subject to the
  1269 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1270 
  1271 * Command tags control specific markup of certain regions of text,
  1272 notably folding and hiding.  Predefined tags include "theory" (for
  1273 theory begin and end), "proof" for proof commands, and "ML" for
  1274 commands involving ML code; the additional tags "visible" and
  1275 "invisible" are unused by default.  Users may give explicit tag
  1276 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1277 interpretation of tags is determined by the LaTeX job during document
  1278 preparation: see option -V of isatool usedir, or options -n and -t of
  1279 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1280 \isadroptag.
  1281 
  1282 Several document versions may be produced at the same time via isatool
  1283 usedir (the generated index.html will link all of them).  Typical
  1284 specifications include ''-V document=theory,proof,ML'' to present
  1285 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1286 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1287 these parts without any formal replacement text.  The Isabelle site
  1288 default settings produce ''document'' and ''outline'' versions as
  1289 specified above.
  1290 
  1291 * Several new antiquotations:
  1292 
  1293   @{term_type term} prints a term with its type annotated;
  1294 
  1295   @{typeof term} prints the type of a term;
  1296 
  1297   @{const const} is the same as @{term const}, but checks that the
  1298   argument is a known logical constant;
  1299 
  1300   @{term_style style term} and @{thm_style style thm} print a term or
  1301   theorem applying a "style" to it
  1302 
  1303   @{ML text}
  1304 
  1305 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1306 definitions, equations, inequations etc., 'concl' printing only the
  1307 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1308 to print the specified premise.  TermStyle.add_style provides an ML
  1309 interface for introducing further styles.  See also the "LaTeX Sugar"
  1310 document practical applications.  The ML antiquotation prints
  1311 type-checked ML expressions verbatim.
  1312 
  1313 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1314 and 'text' support optional locale specification '(in loc)', which
  1315 specifies the default context for interpreting antiquotations.  For
  1316 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1317 
  1318 * Option 'locale=NAME' of antiquotations specifies an alternative
  1319 context interpreting the subsequent argument.  For example: @{thm
  1320 [locale=lattice] inf_assoc}.
  1321 
  1322 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1323 a proof context.
  1324 
  1325 * Proper output of antiquotations for theory commands involving a
  1326 proof context (such as 'locale' or 'theorem (in loc) ...').
  1327 
  1328 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1329 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1330 
  1331 * isatool usedir: new option -C (default true) controls whether option
  1332 -D should include a copy of the original document directory; -C false
  1333 prevents unwanted effects such as copying of administrative CVS data.
  1334 
  1335 
  1336 *** Pure ***
  1337 
  1338 * Considerably improved version of 'constdefs' command.  Now performs
  1339 automatic type-inference of declared constants; additional support for
  1340 local structure declarations (cf. locales and HOL records), see also
  1341 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1342 sequential dependencies of definitions within a single 'constdefs'
  1343 section; moreover, the declared name needs to be an identifier.  If
  1344 all fails, consider to fall back on 'consts' and 'defs' separately.
  1345 
  1346 * Improved indexed syntax and implicit structures.  First of all,
  1347 indexed syntax provides a notational device for subscripted
  1348 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1349 expressions.  Secondly, in a local context with structure
  1350 declarations, number indexes \<^sub>n or the empty index (default
  1351 number 1) refer to a certain fixed variable implicitly; option
  1352 show_structs controls printing of implicit structures.  Typical
  1353 applications of these concepts involve record types and locales.
  1354 
  1355 * New command 'no_syntax' removes grammar declarations (and
  1356 translations) resulting from the given syntax specification, which is
  1357 interpreted in the same manner as for the 'syntax' command.
  1358 
  1359 * 'Advanced' translation functions (parse_translation etc.) may depend
  1360 on the signature of the theory context being presently used for
  1361 parsing/printing, see also isar-ref manual.
  1362 
  1363 * Improved 'oracle' command provides a type-safe interface to turn an
  1364 ML expression of type theory -> T -> term into a primitive rule of
  1365 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1366 is already included here); see also FOL/ex/IffExample.thy;
  1367 INCOMPATIBILITY.
  1368 
  1369 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1370 before); "cI" is no longer bound, use "c.intro" instead.
  1371 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1372 axclasses vs. locales.
  1373 
  1374 * Improved internal renaming of symbolic identifiers -- attach primes
  1375 instead of base 26 numbers.
  1376 
  1377 * New flag show_question_marks controls printing of leading question
  1378 marks in schematic variable names.
  1379 
  1380 * In schematic variable names, *any* symbol following \<^isub> or
  1381 \<^isup> is now treated as part of the base name.  For example, the
  1382 following works without printing of awkward ".0" indexes:
  1383 
  1384   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1385     by simp
  1386 
  1387 * Inner syntax includes (*(*nested*) comments*).
  1388 
  1389 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1390 annotations as "(00...)".
  1391 
  1392 * Clear separation of logical types and nonterminals, where the latter
  1393 may only occur in 'syntax' specifications or type abbreviations.
  1394 Before that distinction was only partially implemented via type class
  1395 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1396 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1397 exotic syntax specifications may require further adaption
  1398 (e.g. Cube/Cube.thy).
  1399 
  1400 * Removed obsolete type class "logic", use the top sort {} instead.
  1401 Note that non-logical types should be declared as 'nonterminals'
  1402 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1403 specifications.
  1404 
  1405 * Attributes 'induct' and 'cases': type or set names may now be
  1406 locally fixed variables as well.
  1407 
  1408 * Simplifier: can now control the depth to which conditional rewriting
  1409 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1410 Limit.
  1411 
  1412 * Simplifier: simplification procedures may now take the current
  1413 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1414 interface), which is very useful for calling the Simplifier
  1415 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1416 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1417 low-level mk_simproc no longer applies Logic.varify internally, to
  1418 allow for use in a context of fixed variables.
  1419 
  1420 * thin_tac now works even if the assumption being deleted contains !!
  1421 or ==>.  More generally, erule now works even if the major premise of
  1422 the elimination rule contains !! or ==>.
  1423 
  1424 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1425 
  1426 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1427 from Pure, which contains all common declarations already.  Both
  1428 theories are defined via plain Isabelle/Isar .thy files.
  1429 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1430 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1431 use isatool fixcpure to adapt your theory and ML sources.
  1432 
  1433 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1434 selections of theorems in named facts via index ranges.
  1435 
  1436 * 'print_theorems': in theory mode, really print the difference
  1437 wrt. the last state (works for interactive theory development only),
  1438 in proof mode print all local facts (cf. 'print_facts');
  1439 
  1440 * 'hide': option '(open)' hides only base names.
  1441 
  1442 * More efficient treatment of intermediate checkpoints in interactive
  1443 theory development.
  1444 
  1445 * Code generator is now invoked via code_module (incremental code
  1446 generation) and code_library (modular code generation, ML structures
  1447 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1448 must be quoted when used as identifiers.
  1449 
  1450 * New 'value' command for reading, evaluating and printing terms using
  1451 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1452 quoted when used as identifier.
  1453 
  1454 
  1455 *** Locales ***
  1456 
  1457 * New commands for the interpretation of locale expressions in
  1458 theories (1), locales (2) and proof contexts (3).  These generate
  1459 proof obligations from the expression specification.  After the
  1460 obligations have been discharged, theorems of the expression are added
  1461 to the theory, target locale or proof context.  The synopsis of the
  1462 commands is a follows:
  1463 
  1464   (1) interpretation expr inst
  1465   (2) interpretation target < expr
  1466   (3) interpret expr inst
  1467 
  1468 Interpretation in theories and proof contexts require a parameter
  1469 instantiation of terms from the current context.  This is applied to
  1470 specifications and theorems of the interpreted expression.
  1471 Interpretation in locales only permits parameter renaming through the
  1472 locale expression.  Interpretation is smart in that interpretations
  1473 that are active already do not occur in proof obligations, neither are
  1474 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1475 inspect active interpretations of a particular locale.  For details,
  1476 see the Isar Reference manual.  Examples can be found in
  1477 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1478 
  1479 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1480 'interpret' instead.
  1481 
  1482 * New context element 'constrains' for adding type constraints to
  1483 parameters.
  1484 
  1485 * Context expressions: renaming of parameters with syntax
  1486 redeclaration.
  1487 
  1488 * Locale declaration: 'includes' disallowed.
  1489 
  1490 * Proper static binding of attribute syntax -- i.e. types / terms /
  1491 facts mentioned as arguments are always those of the locale definition
  1492 context, independently of the context of later invocations.  Moreover,
  1493 locale operations (renaming and type / term instantiation) are applied
  1494 to attribute arguments as expected.
  1495 
  1496 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1497 actual attributes; rare situations may require Attrib.attribute to
  1498 embed those attributes into Attrib.src that lack concrete syntax.
  1499 Attribute implementations need to cooperate properly with the static
  1500 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1501 Attrib.XXX_thm etc. already do the right thing without further
  1502 intervention.  Only unusual applications -- such as "where" or "of"
  1503 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1504 on the context and the facts involved -- may have to assign parsed
  1505 values to argument tokens explicitly.
  1506 
  1507 * Changed parameter management in theorem generation for long goal
  1508 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1509 theorem statement in rare situations.
  1510 
  1511 * Locale inspection command 'print_locale' omits notes elements.  Use
  1512 'print_locale!' to have them included in the output.
  1513 
  1514 
  1515 *** Provers ***
  1516 
  1517 * Provers/hypsubst.ML: improved version of the subst method, for
  1518 single-step rewriting: it now works in bound variable contexts. New is
  1519 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1520 rewrite a different subterm than the original subst method, which is
  1521 still available as 'simplesubst'.
  1522 
  1523 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1524 and quasi orders.
  1525 
  1526 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1527 reflexive-transitive closure of relations.
  1528 
  1529 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1530 limit (previously hard-coded with a value of 20) user-definable.
  1531 
  1532 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1533 is peformed already.  Object-logics merely need to finish their
  1534 initial simpset configuration as before.  INCOMPATIBILITY.
  1535 
  1536 
  1537 *** HOL ***
  1538 
  1539 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1540 
  1541   syntax (epsilon)
  1542     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1543 
  1544 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1545 and x-symbol; use option '-m epsilon' to get it actually printed.
  1546 Moreover, the mathematically important symbolic identifier \<epsilon>
  1547 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1548 
  1549 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1550 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1551 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1552 support corresponding Isar calculations.
  1553 
  1554 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1555 instead of ":".
  1556 
  1557 * theory SetInterval: changed the syntax for open intervals:
  1558 
  1559   Old       New
  1560   {..n(}    {..<n}
  1561   {)n..}    {n<..}
  1562   {m..n(}   {m..<n}
  1563   {)m..n}   {m<..n}
  1564   {)m..n(}  {m<..<n}
  1565 
  1566 The old syntax is still supported but will disappear in the next
  1567 release.  For conversion use the following Emacs search and replace
  1568 patterns (these are not perfect but work quite well):
  1569 
  1570   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1571   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1572 
  1573 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1574 equalities in commutative rings; method 'algebra' provides a generic
  1575 interface.
  1576 
  1577 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1578 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1579 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1580 be a tuple pattern.
  1581 
  1582 Some new syntax forms are available:
  1583 
  1584   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1585   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1586   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1587   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1588 
  1589 The latter form "\<Sum>x < k. e" used to be based on a separate
  1590 function "Summation", which has been discontinued.
  1591 
  1592 * theory Finite_Set: in structured induction proofs, the insert case
  1593 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1594 (insert F x)'.
  1595 
  1596 * The 'refute' command has been extended to support a much larger
  1597 fragment of HOL, including axiomatic type classes, constdefs and
  1598 typedefs, inductive datatypes and recursion.
  1599 
  1600 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1601 Requires zChaff with proof generation to be installed.  See
  1602 HOL/ex/SAT_Examples.thy for examples.
  1603 
  1604 * Datatype induction via method 'induct' now preserves the name of the
  1605 induction variable. For example, when proving P(xs::'a list) by
  1606 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1607 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1608 in unstructured proof scripts.
  1609 
  1610 * Reworked implementation of records.  Improved scalability for
  1611 records with many fields, avoiding performance problems for type
  1612 inference. Records are no longer composed of nested field types, but
  1613 of nested extension types. Therefore the record type only grows linear
  1614 in the number of extensions and not in the number of fields.  The
  1615 top-level (users) view on records is preserved.  Potential
  1616 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1617 old record representation. The type generated for a record is called
  1618 <record_name>_ext_type.
  1619 
  1620 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1621 proofs triggered by a record definition or a simproc (if
  1622 quick_and_dirty is enabled).  Definitions of large records can take
  1623 quite long.
  1624 
  1625 New simproc record_upd_simproc for simplification of multiple record
  1626 updates enabled by default.  Moreover, trivial updates are also
  1627 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1628 occasionally, since simplification is more powerful by default.
  1629 
  1630 * typedef: proper support for polymorphic sets, which contain extra
  1631 type-variables in the term.
  1632 
  1633 * Simplifier: automatically reasons about transitivity chains
  1634 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1635 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1636 old proofs break occasionally as simplification may now solve more
  1637 goals than previously.
  1638 
  1639 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1640 present.  Works for all partial orders (class "order"), in particular
  1641 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1642 just like y <= x.
  1643 
  1644 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1645 bound variable or a constant then the let is unfolded.  Otherwise
  1646 first a is simplified to b, and then f b is simplified to g. If
  1647 possible we abstract b from g arriving at "let x = b in h x",
  1648 otherwise we unfold the let and arrive at g.  The simproc can be
  1649 enabled/disabled by the reference use_let_simproc.  Potential
  1650 INCOMPATIBILITY since simplification is more powerful by default.
  1651 
  1652 * Classical reasoning: the meson method now accepts theorems as arguments.
  1653 
  1654 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1655 jobs to provide advice on the provability of subgoals.
  1656 
  1657 * Theory OrderedGroup and Ring_and_Field: various additions and
  1658 improvements to faciliate calculations involving equalities and
  1659 inequalities.
  1660 
  1661 The following theorems have been eliminated or modified
  1662 (INCOMPATIBILITY):
  1663 
  1664   abs_eq             now named abs_of_nonneg
  1665   abs_of_ge_0        now named abs_of_nonneg
  1666   abs_minus_eq       now named abs_of_nonpos
  1667   imp_abs_id         now named abs_of_nonneg
  1668   imp_abs_neg_id     now named abs_of_nonpos
  1669   mult_pos           now named mult_pos_pos
  1670   mult_pos_le        now named mult_nonneg_nonneg
  1671   mult_pos_neg_le    now named mult_nonneg_nonpos
  1672   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1673   mult_neg           now named mult_neg_neg
  1674   mult_neg_le        now named mult_nonpos_nonpos
  1675 
  1676 * Theory Parity: added rules for simplifying exponents.
  1677 
  1678 * Theory List:
  1679 
  1680 The following theorems have been eliminated or modified
  1681 (INCOMPATIBILITY):
  1682 
  1683   list_all_Nil       now named list_all.simps(1)
  1684   list_all_Cons      now named list_all.simps(2)
  1685   list_all_conv      now named list_all_iff
  1686   set_mem_eq         now named mem_iff
  1687 
  1688 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1689 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1690 
  1691 
  1692 *** HOL-Complex ***
  1693 
  1694 * Theory RealDef: better support for embedding natural numbers and
  1695 integers in the reals.
  1696 
  1697 The following theorems have been eliminated or modified
  1698 (INCOMPATIBILITY):
  1699 
  1700   exp_ge_add_one_self  now requires no hypotheses
  1701   real_of_int_add      reversed direction of equality (use [symmetric])
  1702   real_of_int_minus    reversed direction of equality (use [symmetric])
  1703   real_of_int_diff     reversed direction of equality (use [symmetric])
  1704   real_of_int_mult     reversed direction of equality (use [symmetric])
  1705 
  1706 * Theory RComplete: expanded support for floor and ceiling functions.
  1707 
  1708 * Theory Ln is new, with properties of the natural logarithm
  1709 
  1710 * Hyperreal: There is a new type constructor "star" for making
  1711 nonstandard types.  The old type names are now type synonyms:
  1712 
  1713   hypreal = real star
  1714   hypnat = nat star
  1715   hcomplex = complex star
  1716 
  1717 * Hyperreal: Many groups of similarly-defined constants have been
  1718 replaced by polymorphic versions (INCOMPATIBILITY):
  1719 
  1720   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1721 
  1722   starset      <-- starsetNat, starsetC
  1723   *s*          <-- *sNat*, *sc*
  1724   starset_n    <-- starsetNat_n, starsetC_n
  1725   *sn*         <-- *sNatn*, *scn*
  1726   InternalSets <-- InternalNatSets, InternalCSets
  1727 
  1728   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1729   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1730   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1731   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1732   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1733 
  1734 * Hyperreal: Many type-specific theorems have been removed in favor of
  1735 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1736 
  1737   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1738   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1739   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1740   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1741   right_minus <-- hypreal_add_minus
  1742   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1743   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1744   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1745   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1746   mult_1_right <-- hcomplex_mult_one_right
  1747   mult_zero_left <-- hcomplex_mult_zero_left
  1748   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1749   right_distrib <-- hypnat_add_mult_distrib2
  1750   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1751   right_inverse <-- hypreal_mult_inverse
  1752   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1753   order_refl <-- {hypreal,hypnat}_le_refl
  1754   order_trans <-- {hypreal,hypnat}_le_trans
  1755   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1756   order_less_le <-- {hypreal,hypnat}_less_le
  1757   linorder_linear <-- {hypreal,hypnat}_le_linear
  1758   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1759   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1760   add_nonneg_nonneg <-- hypreal_le_add_order
  1761 
  1762 * Hyperreal: Separate theorems having to do with type-specific
  1763 versions of constants have been merged into theorems that apply to the
  1764 new polymorphic constants (INCOMPATIBILITY):
  1765 
  1766   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1767   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1768   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1769   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1770   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1771   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1772   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1773   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1774   STAR_diff <-- {STAR,STARC}_diff
  1775   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1776     STARC_hcomplex_of_complex}_image_subset
  1777   starset_n_Un <-- starset{Nat,C}_n_Un
  1778   starset_n_Int <-- starset{Nat,C}_n_Int
  1779   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1780   starset_n_diff <-- starset{Nat,C}_n_diff
  1781   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1782   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1783   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1784   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1785   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1786   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1787   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1788   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1789   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1790   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1791   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1792   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1793   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1794   starfun_diff <-- starfun{C,RC,CR}_diff
  1795   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1796   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1797   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1798   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1799   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1800   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1801   starfun_Id <-- starfunC_Id
  1802   starfun_approx <-- starfun{Nat,CR}_approx
  1803   starfun_capprox <-- starfun{C,RC}_capprox
  1804   starfun_abs <-- starfunNat_rabs
  1805   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1806   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1807   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1808   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1809   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1810   starfun_add_approx <-- starfunCR_add_approx
  1811   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1812   starfun_divide <-- starfun{C,CR,RC}_divide
  1813   starfun_n <-- starfun{Nat,C}_n
  1814   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1815   starfun_n_add <-- starfun{Nat,C}_n_add
  1816   starfun_n_add_minus <-- starfunNat_n_add_minus
  1817   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1818   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1819   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1820 
  1821   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1822   star_n_minus <-- {hypreal,hcomplex}_minus
  1823   star_n_diff <-- {hypreal,hcomplex}_diff
  1824   star_n_mult <-- {hypreal,hcomplex}_mult
  1825   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1826   star_n_le <-- {hypreal,hypnat}_le
  1827   star_n_less <-- {hypreal,hypnat}_less
  1828   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1829   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1830   star_n_abs <-- hypreal_hrabs
  1831   star_n_divide <-- hcomplex_divide
  1832 
  1833   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1834   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1835   star_of_diff <-- hypreal_of_real_diff
  1836   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1837   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1838   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1839   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1840   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1841   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1842   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1843   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1844   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1845   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1846   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1847   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1848   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1849   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1850   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1851   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1852   star_of_power <-- hypreal_of_real_power
  1853   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1854 
  1855 * Hyperreal: new method "transfer" that implements the transfer
  1856 principle of nonstandard analysis. With a subgoal that mentions
  1857 nonstandard types like "'a star", the command "apply transfer"
  1858 replaces it with an equivalent one that mentions only standard types.
  1859 To be successful, all free variables must have standard types; non-
  1860 standard variables must have explicit universal quantifiers.
  1861 
  1862 * Hyperreal: A theory of Taylor series.
  1863 
  1864 
  1865 *** HOLCF ***
  1866 
  1867 * Discontinued special version of 'constdefs' (which used to support
  1868 continuous functions) in favor of the general Pure one with full
  1869 type-inference.
  1870 
  1871 * New simplification procedure for solving continuity conditions; it
  1872 is much faster on terms with many nested lambda abstractions (cubic
  1873 instead of exponential time).
  1874 
  1875 * New syntax for domain package: selector names are now optional.
  1876 Parentheses should be omitted unless argument is lazy, for example:
  1877 
  1878   domain 'a stream = cons "'a" (lazy "'a stream")
  1879 
  1880 * New command 'fixrec' for defining recursive functions with pattern
  1881 matching; defining multiple functions with mutual recursion is also
  1882 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1883 sinr, or any data constructor defined by the domain package. The given
  1884 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1885 syntax and examples.
  1886 
  1887 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1888 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1889 but the proof obligation additionally includes an admissibility
  1890 requirement. The packages generate instances of class cpo or pcpo,
  1891 with continuity and strictness theorems for Rep and Abs.
  1892 
  1893 * HOLCF: Many theorems have been renamed according to a more standard naming
  1894 scheme (INCOMPATIBILITY):
  1895 
  1896   foo_inject:  "foo$x = foo$y ==> x = y"
  1897   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1898   foo_less:    "(foo$x << foo$y) = (x << y)"
  1899   foo_strict:  "foo$UU = UU"
  1900   foo_defined: "... ==> foo$x ~= UU"
  1901   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1902 
  1903 
  1904 *** ZF ***
  1905 
  1906 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1907 including the First Isomorphism Theorem (on quotienting by the kernel
  1908 of a homomorphism).
  1909 
  1910 * ZF/Simplifier: install second copy of type solver that actually
  1911 makes use of TC rules declared to Isar proof contexts (or locales);
  1912 the old version is still required for ML proof scripts.
  1913 
  1914 
  1915 *** Cube ***
  1916 
  1917 * Converted to Isar theory format; use locales instead of axiomatic
  1918 theories.
  1919 
  1920 
  1921 *** ML ***
  1922 
  1923 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1924 for ||>, ||>>, |>>,
  1925 
  1926 * Pure/library.ML no longer defines its own option datatype, but uses
  1927 that of the SML basis, which has constructors NONE and SOME instead of
  1928 None and Some, as well as exception Option.Option instead of OPTION.
  1929 The functions the, if_none, is_some, is_none have been adapted
  1930 accordingly, while Option.map replaces apsome.
  1931 
  1932 * Pure/library.ML: the exception LIST has been given up in favour of
  1933 the standard exceptions Empty and Subscript, as well as
  1934 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1935 superceded by the standard hd and tl functions etc.
  1936 
  1937 A number of basic list functions are no longer exported to the ML
  1938 toplevel, as they are variants of predefined functions.  The following
  1939 suggests how one can translate existing code:
  1940 
  1941     rev_append xs ys = List.revAppend (xs, ys)
  1942     nth_elem (i, xs) = List.nth (xs, i)
  1943     last_elem xs = List.last xs
  1944     flat xss = List.concat xss
  1945     seq fs = List.app fs
  1946     partition P xs = List.partition P xs
  1947     mapfilter f xs = List.mapPartial f xs
  1948 
  1949 * Pure/library.ML: several combinators for linear functional
  1950 transformations, notably reverse application and composition:
  1951 
  1952   x |> f                f #> g
  1953   (x, y) |-> f          f #-> g
  1954 
  1955 * Pure/library.ML: introduced/changed precedence of infix operators:
  1956 
  1957   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1958   infix 2 ?;
  1959   infix 3 o oo ooo oooo;
  1960   infix 4 ~~ upto downto;
  1961 
  1962 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1963 infix operators.
  1964 
  1965 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1966 fold_map support linear functional transformations and nesting.  For
  1967 example:
  1968 
  1969   fold f [x1, ..., xN] y =
  1970     y |> f x1 |> ... |> f xN
  1971 
  1972   (fold o fold) f [xs1, ..., xsN] y =
  1973     y |> fold f xs1 |> ... |> fold f xsN
  1974 
  1975   fold f [x1, ..., xN] =
  1976     f x1 #> ... #> f xN
  1977 
  1978   (fold o fold) f [xs1, ..., xsN] =
  1979     fold f xs1 #> ... #> fold f xsN
  1980 
  1981 * Pure/library.ML: the following selectors on type 'a option are
  1982 available:
  1983 
  1984   the:               'a option -> 'a  (*partial*)
  1985   these:             'a option -> 'a  where 'a = 'b list
  1986   the_default: 'a -> 'a option -> 'a
  1987   the_list:          'a option -> 'a list
  1988 
  1989 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1990 basic operations for association lists, following natural argument
  1991 order; moreover the explicit equality predicate passed here avoids
  1992 potentially expensive polymorphic runtime equality checks.
  1993 The old functions may be expressed as follows:
  1994 
  1995   assoc = uncurry (AList.lookup (op =))
  1996   assocs = these oo AList.lookup (op =)
  1997   overwrite = uncurry (AList.update (op =)) o swap
  1998 
  1999 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2000 
  2001   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2002   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2003 
  2004 replacing make_keylist and keyfilter (occassionally used)
  2005 Naive rewrites:
  2006 
  2007   make_keylist = AList.make
  2008   keyfilter = AList.find (op =)
  2009 
  2010 * eq_fst and eq_snd now take explicit equality parameter, thus
  2011   avoiding eqtypes. Naive rewrites:
  2012 
  2013     eq_fst = eq_fst (op =)
  2014     eq_snd = eq_snd (op =)
  2015 
  2016 * Removed deprecated apl and apr (rarely used).
  2017   Naive rewrites:
  2018 
  2019     apl (n, op) =>>= curry op n
  2020     apr (op, m) =>>= fn n => op (n, m)
  2021 
  2022 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2023 provides a reasonably efficient light-weight implementation of sets as
  2024 lists.
  2025 
  2026 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2027 few new operations; existing lookup and update are now curried to
  2028 follow natural argument order (for use with fold etc.);
  2029 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2030 
  2031 * Pure/General: output via the Isabelle channels of
  2032 writeln/warning/error etc. is now passed through Output.output, with a
  2033 hook for arbitrary transformations depending on the print_mode
  2034 (cf. Output.add_mode -- the first active mode that provides a output
  2035 function wins).  Already formatted output may be embedded into further
  2036 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2037 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2038 accommodate easy composition of diagnostic messages etc.  Programmers
  2039 rarely need to care about Output.output or Output.raw at all, with
  2040 some notable exceptions: Output.output is required when bypassing the
  2041 standard channels (writeln etc.), or in token translations to produce
  2042 properly formatted results; Output.raw is required when capturing
  2043 already output material that will eventually be presented to the user
  2044 a second time.  For the default print mode, both Output.output and
  2045 Output.raw have no effect.
  2046 
  2047 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2048 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2049 cumulative results are displayed at the end of a batch session.
  2050 
  2051 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2052 replaced by File.platform_path and File.shell_path (with appropriate
  2053 hooks).  This provides a clean interface for unusual systems where the
  2054 internal and external process view of file names are different.
  2055 
  2056 * Pure: more efficient orders for basic syntactic entities: added
  2057 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2058 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2059 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2060 orders now -- potential INCOMPATIBILITY for code that depends on a
  2061 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2062 Library.sort_strings on result).
  2063 
  2064 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2065 fold_types traverse types/terms from left to right, observing natural
  2066 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2067 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2068 
  2069 * Pure: name spaces have been refined, with significant changes of the
  2070 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2071 to extern(_table).  The plain name entry path is superceded by a
  2072 general 'naming' context, which also includes the 'policy' to produce
  2073 a fully qualified name and external accesses of a fully qualified
  2074 name; NameSpace.extend is superceded by context dependent
  2075 Sign.declare_name.  Several theory and proof context operations modify
  2076 the naming context.  Especially note Theory.restore_naming and
  2077 ProofContext.restore_naming to get back to a sane state; note that
  2078 Theory.add_path is no longer sufficient to recover from
  2079 Theory.absolute_path in particular.
  2080 
  2081 * Pure: new flags short_names (default false) and unique_names
  2082 (default true) for controlling output of qualified names.  If
  2083 short_names is set, names are printed unqualified.  If unique_names is
  2084 reset, the name prefix is reduced to the minimum required to achieve
  2085 the original result when interning again, even if there is an overlap
  2086 with earlier declarations.
  2087 
  2088 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2089 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2090 (useful for printing error messages).  INCOMPATIBILITY.
  2091 
  2092 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2093 Theory.theory are now identified, referring to the universal
  2094 Context.theory (see Pure/context.ML).  Actual signature and theory
  2095 content is managed as theory data.  The old code and interfaces were
  2096 spread over many files and structures; the new arrangement introduces
  2097 considerable INCOMPATIBILITY to gain more clarity:
  2098 
  2099   Context -- theory management operations (name, identity, inclusion,
  2100     parents, ancestors, merge, etc.), plus generic theory data;
  2101 
  2102   Sign -- logical signature and syntax operations (declaring consts,
  2103     types, etc.), plus certify/read for common entities;
  2104 
  2105   Theory -- logical theory operations (stating axioms, definitions,
  2106     oracles), plus a copy of logical signature operations (consts,
  2107     types, etc.); also a few basic management operations (Theory.copy,
  2108     Theory.merge, etc.)
  2109 
  2110 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2111 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2112 for convenience -- they merely return the theory.
  2113 
  2114 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2115 
  2116 * Pure: the Isar proof context type is already defined early in Pure
  2117 as Context.proof (note that ProofContext.context and Proof.context are
  2118 aliases, where the latter is the preferred name).  This enables other
  2119 Isabelle components to refer to that type even before Isar is present.
  2120 
  2121 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2122 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2123 any of these kinds.  For example, Sign.intern typeK is now
  2124 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2125 Theory.hide_types.  Also note that former
  2126 Theory.hide_classes/types/consts are now
  2127 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2128 internalize their arguments!  INCOMPATIBILITY.
  2129 
  2130 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2131 datatype thmref (with constructors Name and NameSelection) instead of
  2132 plain string -- INCOMPATIBILITY;
  2133 
  2134 * Pure: cases produced by proof methods specify options, where NONE
  2135 means to remove case bindings -- INCOMPATIBILITY in
  2136 (RAW_)METHOD_CASES.
  2137 
  2138 * Pure: the following operations retrieve axioms or theorems from a
  2139 theory node or theory hierarchy, respectively:
  2140 
  2141   Theory.axioms_of: theory -> (string * term) list
  2142   Theory.all_axioms_of: theory -> (string * term) list
  2143   PureThy.thms_of: theory -> (string * thm) list
  2144   PureThy.all_thms_of: theory -> (string * thm) list
  2145 
  2146 * Pure: print_tac now outputs the goal through the trace channel.
  2147 
  2148 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2149 Reference Toplevel.debug (default false) controls detailed printing
  2150 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2151 controls execution profiling -- set to 1 for time and 2 for space
  2152 (both increase the runtime).
  2153 
  2154 * Isar session: The initial use of ROOT.ML is now always timed,
  2155 i.e. the log will show the actual process times, in contrast to the
  2156 elapsed wall-clock time that the outer shell wrapper produces.
  2157 
  2158 * Simplifier: improved handling of bound variables (nameless
  2159 representation, avoid allocating new strings).  Simprocs that invoke
  2160 the Simplifier recursively should use Simplifier.inherit_bounds to
  2161 avoid local name clashes.  Failure to do so produces warnings
  2162 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2163 for further details.
  2164 
  2165 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2166 bindings for all theorems stored within a given theory; this may help
  2167 in porting non-Isar theories to Isar ones, while keeping ML proof
  2168 scripts for the time being.
  2169 
  2170 * ML operator HTML.with_charset specifies the charset begin used for
  2171 generated HTML files.  For example:
  2172 
  2173   HTML.with_charset "utf-8" use_thy "Hebrew";
  2174   HTML.with_charset "utf-8" use_thy "Chinese";
  2175 
  2176 
  2177 *** System ***
  2178 
  2179 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2180 isabelle, isatool etc.).
  2181 
  2182 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2183 isatool doc, isatool mkdir, display_drafts etc.).
  2184 
  2185 * isatool usedir: option -f allows specification of the ML file to be
  2186 used by Isabelle; default is ROOT.ML.
  2187 
  2188 * New isatool version outputs the version identifier of the Isabelle
  2189 distribution being used.
  2190 
  2191 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2192 (containing Boolean satisfiability problems) into Isabelle/HOL
  2193 theories.
  2194 
  2195 
  2196 
  2197 New in Isabelle2004 (April 2004)
  2198 --------------------------------
  2199 
  2200 *** General ***
  2201 
  2202 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2203   Replaces linorder.ML.
  2204 
  2205 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2206   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2207   (\<a>...\<z>), are now considered normal letters, and can therefore
  2208   be used anywhere where an ASCII letter (a...zA...Z) has until
  2209   now. COMPATIBILITY: This obviously changes the parsing of some
  2210   terms, especially where a symbol has been used as a binder, say
  2211   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2212   as an identifier.  Fix it by inserting a space around former
  2213   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2214   existing theory and ML files.
  2215 
  2216 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2217 
  2218 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2219   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2220   a normal (but invisible) letter. For multiple letter subscripts repeat
  2221   \<^isub> like this: x\<^isub>1\<^isub>2.
  2222 
  2223 * Pure: There are now sub-/superscripts that can span more than one
  2224   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2225   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2226   superscript. The new control characters are not identifier parts.
  2227 
  2228 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2229   content of "..." to the latex file instead of \isacntrl... . The "..."
  2230   may consist of any printable characters excluding the end bracket >.
  2231 
  2232 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2233   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2234   declare constants "final", which prevents their being given a definition
  2235   later.  It is useful for constants whose behaviour is fixed axiomatically
  2236   rather than definitionally, such as the meta-logic connectives.
  2237 
  2238 * Pure: 'instance' now handles general arities with general sorts
  2239   (i.e. intersections of classes),
  2240 
  2241 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2242   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2243   It can be changed to alter the colors/layout of generated pages.
  2244 
  2245 
  2246 *** Isar ***
  2247 
  2248 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2249   cut_tac, subgoal_tac and thin_tac:
  2250   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2251     locales are no longer forced to write Isar proof scripts.
  2252     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2253     emulations.
  2254   - INCOMPATIBILITY: names of variables to be instantiated may no
  2255     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2256     This is consistent with the instantiation attribute "where".
  2257 
  2258 * Attributes "where" and "of":
  2259   - Now take type variables of instantiated theorem into account when reading
  2260     the instantiation string.  This fixes a bug that caused instantiated
  2261     theorems to have too special types in some circumstances.
  2262   - "where" permits explicit instantiations of type variables.
  2263 
  2264 * Calculation commands "moreover" and "also" no longer interfere with
  2265   current facts ("this"), admitting arbitrary combinations with "then"
  2266   and derived forms.
  2267 
  2268 * Locales:
  2269   - Goal statements involving the context element "includes" no longer
  2270     generate theorems with internal delta predicates (those ending on
  2271     "_axioms") in the premise.
  2272     Resolve particular premise with <locale>.intro to obtain old form.
  2273   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2274     specification and "includes" elements in goal statement.
  2275   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2276     [intro?] and [elim?] (respectively) by default.
  2277   - Experimental command for instantiation of locales in proof contexts:
  2278         instantiate <label>[<attrs>]: <loc>
  2279     Instantiates locale <loc> and adds all its theorems to the current context
  2280     taking into account their attributes.  Label and attrs are optional
  2281     modifiers, like in theorem declarations.  If present, names of
  2282     instantiated theorems are qualified with <label>, and the attributes
  2283     <attrs> are applied after any attributes these theorems might have already.
  2284       If the locale has assumptions, a chained fact of the form
  2285     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2286     are derived.  The command does not support old-style locales declared
  2287     with "locale (open)".
  2288       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2289 
  2290 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2291   (Isar) contexts.
  2292 
  2293 
  2294 *** HOL ***
  2295 
  2296 * Proof import: new image HOL4 contains the imported library from
  2297   the HOL4 system with about 2500 theorems. It is imported by
  2298   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2299   can be used like any other Isabelle image.  See
  2300   HOL/Import/HOL/README for more information.
  2301 
  2302 * Simplifier:
  2303   - Much improved handling of linear and partial orders.
  2304     Reasoners for linear and partial orders are set up for type classes
  2305     "linorder" and "order" respectively, and are added to the default simpset
  2306     as solvers.  This means that the simplifier can build transitivity chains
  2307     to solve goals from the assumptions.
  2308   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2309     of blast or auto after simplification become unnecessary because the goal
  2310     is solved by simplification already.
  2311 
  2312 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2313     all proved in axiomatic type classes for semirings, rings and fields.
  2314 
  2315 * Numerics:
  2316   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2317     now formalized using the Ring_and_Field theory mentioned above.
  2318   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2319     than before, because now they are set up once in a generic manner.
  2320   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2321     Look for the general versions in Ring_and_Field (and Power if they concern
  2322     exponentiation).
  2323 
  2324 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2325 
  2326 * Records:
  2327   - Record types are now by default printed with their type abbreviation
  2328     instead of the list of all field types. This can be configured via
  2329     the reference "print_record_type_abbr".
  2330   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2331     (not enabled by default).
  2332   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2333     EX x. x = sel r to True (not enabled by default).
  2334   - Tactic "record_split_simp_tac" to split and simplify records added.
  2335 
  2336 * 'specification' command added, allowing for definition by
  2337   specification.  There is also an 'ax_specification' command that
  2338   introduces the new constants axiomatically.
  2339 
  2340 * arith(_tac) is now able to generate counterexamples for reals as well.
  2341 
  2342 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2343 
  2344 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2345   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2346 
  2347 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2348   matrix theory to linear programming.
  2349 
  2350 * Unions and Intersections:
  2351   The latex output syntax of UN and INT has been changed
  2352   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2353   i.e. the index formulae has become a subscript.
  2354   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2355 
  2356 * Unions and Intersections over Intervals:
  2357   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2358   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2359   like in normal math, and corresponding versions for < and for intersection.
  2360 
  2361 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2362   lexicographic dictonary ordering has been added as "lexord".
  2363 
  2364 * ML: the legacy theory structures Int and List have been removed. They had
  2365   conflicted with ML Basis Library structures having the same names.
  2366 
  2367 * 'refute' command added to search for (finite) countermodels.  Only works
  2368   for a fragment of HOL.  The installation of an external SAT solver is
  2369   highly recommended.  See "HOL/Refute.thy" for details.
  2370 
  2371 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2372   formulae under an assignment of free variables to random values.
  2373   In contrast to 'refute', it can deal with inductive datatypes,
  2374   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2375   for examples.
  2376 
  2377 
  2378 *** HOLCF ***
  2379 
  2380 * Streams now come with concatenation and are part of the HOLCF image
  2381 
  2382 
  2383 
  2384 New in Isabelle2003 (May 2003)
  2385 ------------------------------
  2386 
  2387 *** General ***
  2388 
  2389 * Provers/simplifier:
  2390 
  2391   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2392     Assumptions are now subject to complete mutual simplification,
  2393     not just from left to right. The simplifier now preserves
  2394     the order of assumptions.
  2395 
  2396     Potential INCOMPATIBILITY:
  2397 
  2398     -- simp sometimes diverges where the old version did
  2399        not, e.g. invoking simp on the goal
  2400 
  2401         [| P (f x); y = x; f x = f y |] ==> Q
  2402 
  2403        now gives rise to the infinite reduction sequence
  2404 
  2405         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2406 
  2407        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2408        kind of problem.
  2409 
  2410     -- Tactics combining classical reasoner and simplification (such as auto)
  2411        are also affected by this change, because many of them rely on
  2412        simp. They may sometimes diverge as well or yield a different numbers
  2413        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2414        in case of problems. Sometimes subsequent calls to the classical
  2415        reasoner will fail because a preceeding call to the simplifier too
  2416        eagerly simplified the goal, e.g. deleted redundant premises.
  2417 
  2418   - The simplifier trace now shows the names of the applied rewrite rules
  2419 
  2420   - You can limit the number of recursive invocations of the simplifier
  2421     during conditional rewriting (where the simplifie tries to solve the
  2422     conditions before applying the rewrite rule):
  2423     ML "simp_depth_limit := n"
  2424     where n is an integer. Thus you can force termination where previously
  2425     the simplifier would diverge.
  2426 
  2427   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2428 
  2429   - No longer aborts on failed congruence proof.  Instead, the
  2430     congruence is ignored.
  2431 
  2432 * Pure: New generic framework for extracting programs from constructive
  2433   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2434   as HOL/Extraction for some case studies.
  2435 
  2436 * Pure: The main goal of the proof state is no longer shown by default, only
  2437 the subgoals. This behaviour is controlled by a new flag.
  2438    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2439 (ML: Proof.show_main_goal).
  2440 
  2441 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2442 rules whose conclusion matches subgoal 1:
  2443       PG menu: Isabelle/Isar -> Show me -> matching rules
  2444 The rules are ordered by how closely they match the subgoal.
  2445 In particular, rules that solve a subgoal outright are displayed first
  2446 (or rather last, the way they are printed).
  2447 (ML: ProofGeneral.print_intros())
  2448 
  2449 * Pure: New flag trace_unify_fail causes unification to print
  2450 diagnostic information (PG: in trace buffer) when it fails. This is
  2451 useful for figuring out why single step proofs like rule, erule or
  2452 assumption failed.
  2453 
  2454 * Pure: Locale specifications now produce predicate definitions
  2455 according to the body of text (covering assumptions modulo local
  2456 definitions); predicate "loc_axioms" covers newly introduced text,
  2457 while "loc" is cumulative wrt. all included locale expressions; the
  2458 latter view is presented only on export into the global theory
  2459 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2460 on the old view without predicates;
  2461 
  2462 * Pure: predefined locales "var" and "struct" are useful for sharing
  2463 parameters (as in CASL, for example); just specify something like
  2464 ``var x + var y + struct M'' as import;
  2465 
  2466 * Pure: improved thms_containing: proper indexing of facts instead of
  2467 raw theorems; check validity of results wrt. current name space;
  2468 include local facts of proof configuration (also covers active
  2469 locales), cover fixed variables in index; may use "_" in term
  2470 specification; an optional limit for the number of printed facts may
  2471 be given (the default is 40);
  2472 
  2473 * Pure: disallow duplicate fact bindings within new-style theory files
  2474 (batch-mode only);
  2475 
  2476 * Provers: improved induct method: assumptions introduced by case
  2477 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2478 the goal statement); "foo" still refers to all facts collectively;
  2479 
  2480 * Provers: the function blast.overloaded has been removed: all constants
  2481 are regarded as potentially overloaded, which improves robustness in exchange
  2482 for slight decrease in efficiency;
  2483 
  2484 * Provers/linorder: New generic prover for transitivity reasoning over
  2485 linear orders.  Note: this prover is not efficient!
  2486 
  2487 * Isar: preview of problems to finish 'show' now produce an error
  2488 rather than just a warning (in interactive mode);
  2489 
  2490 
  2491 *** HOL ***
  2492 
  2493 * arith(_tac)
  2494 
  2495  - Produces a counter example if it cannot prove a goal.
  2496    Note that the counter example may be spurious if the goal is not a formula
  2497    of quantifier-free linear arithmetic.
  2498    In ProofGeneral the counter example appears in the trace buffer.
  2499 
  2500  - Knows about div k and mod k where k is a numeral of type nat or int.
  2501 
  2502  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2503    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2504    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2505 
  2506 * simp's arithmetic capabilities have been enhanced a bit: it now
  2507 takes ~= in premises into account (by performing a case split);
  2508 
  2509 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2510 are distributed over a sum of terms;
  2511 
  2512 * New tactic "trans_tac" and method "trans" instantiate
  2513 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2514 "<=", "<" and "=").
  2515 
  2516 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2517 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2518 
  2519 * 'typedef' command has new option "open" to suppress the set
  2520 definition;
  2521 
  2522 * functions Min and Max on finite sets have been introduced (theory
  2523 Finite_Set);
  2524 
  2525 * attribute [symmetric] now works for relations as well; it turns
  2526 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2527 
  2528 * induct over a !!-quantified statement (say !!x1..xn):
  2529   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2530 
  2531 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2532 %x. None. Warning: empty_def now refers to the previously hidden definition
  2533 of the empty set.
  2534 
  2535 * Algebra: formalization of classical algebra.  Intended as base for
  2536 any algebraic development in Isabelle.  Currently covers group theory
  2537 (up to Sylow's theorem) and ring theory (Universal Property of
  2538 Univariate Polynomials).  Contributions welcome;
  2539 
  2540 * GroupTheory: deleted, since its material has been moved to Algebra;
  2541 
  2542 * Complex: new directory of the complex numbers with numeric constants,
  2543 nonstandard complex numbers, and some complex analysis, standard and
  2544 nonstandard (Jacques Fleuriot);
  2545 
  2546 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2547 
  2548 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2549 Fleuriot);
  2550 
  2551 * Real/HahnBanach: updated and adapted to locales;
  2552 
  2553 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2554 Gray and Kramer);
  2555 
  2556 * UNITY: added the Meier-Sanders theory of progress sets;
  2557 
  2558 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2559 as abstract algorithms, instantiated to the JVM;
  2560 
  2561 * Bali: Java source language formalization. Type system, operational
  2562 semantics, axiomatic semantics. Supported language features:
  2563 classes, interfaces, objects,virtual methods, static methods,
  2564 static/instance fields, arrays, access modifiers, definite
  2565 assignment, exceptions.
  2566 
  2567 
  2568 *** ZF ***
  2569 
  2570 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2571 universe, etc.);
  2572 
  2573 * Main ZF: virtually all theories converted to new-style format;
  2574 
  2575 
  2576 *** ML ***
  2577 
  2578 * Pure: Tactic.prove provides sane interface for internal proofs;
  2579 omits the infamous "standard" operation, so this is more appropriate
  2580 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2581 
  2582 * Pure: improved error reporting of simprocs;
  2583 
  2584 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2585 up simprocs;
  2586 
  2587 
  2588 *** Document preparation ***
  2589 
  2590 * uses \par instead of \\ for line breaks in theory text. This may
  2591 shift some page breaks in large documents. To get the old behaviour
  2592 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2593 
  2594 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2595 other packages
  2596 
  2597 * \<euro> now needs package babel/greek instead of marvosym (which
  2598 broke \Rightarrow)
  2599 
  2600 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2601 textcomp package)
  2602 
  2603 
  2604 
  2605 New in Isabelle2002 (March 2002)
  2606 --------------------------------
  2607 
  2608 *** Document preparation ***
  2609 
  2610 * greatly simplified document preparation setup, including more
  2611 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2612 instructive isatool mkdir; users should basically be able to get
  2613 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2614 users may run a separate document processing stage manually like this:
  2615 "isatool usedir -D output HOL Test && isatool document Test/output";
  2616 
  2617 * theory dependency graph may now be incorporated into documents;
  2618 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2619 with \includegraphics of LaTeX;
  2620 
  2621 * proper spacing of consecutive markup elements, especially text
  2622 blocks after section headings;
  2623 
  2624 * support bold style (for single symbols only), input syntax is like
  2625 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2626 
  2627 * \<bullet> is now output as bold \cdot by default, which looks much
  2628 better in printed text;
  2629 
  2630 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2631 note that these symbols are currently unavailable in Proof General /
  2632 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2633 
  2634 * isatool latex no longer depends on changed TEXINPUTS, instead
  2635 isatool document copies the Isabelle style files to the target
  2636 location;
  2637 
  2638 
  2639 *** Isar ***
  2640 
  2641 * Pure/Provers: improved proof by cases and induction;
  2642   - 'case' command admits impromptu naming of parameters (such as
  2643     "case (Suc n)");
  2644   - 'induct' method divinates rule instantiation from the inductive
  2645     claim; no longer requires excessive ?P bindings for proper
  2646     instantiation of cases;
  2647   - 'induct' method properly enumerates all possibilities of set/type
  2648     rules; as a consequence facts may be also passed through *type*
  2649     rules without further ado;
  2650   - 'induct' method now derives symbolic cases from the *rulified*
  2651     rule (before it used to rulify cases stemming from the internal
  2652     atomized version); this means that the context of a non-atomic
  2653     statement becomes is included in the hypothesis, avoiding the
  2654     slightly cumbersome show "PROP ?case" form;
  2655   - 'induct' may now use elim-style induction rules without chaining
  2656     facts, using ``missing'' premises from the goal state; this allows
  2657     rules stemming from inductive sets to be applied in unstructured
  2658     scripts, while still benefitting from proper handling of non-atomic
  2659     statements; NB: major inductive premises need to be put first, all
  2660     the rest of the goal is passed through the induction;
  2661   - 'induct' proper support for mutual induction involving non-atomic
  2662     rule statements (uses the new concept of simultaneous goals, see
  2663     below);
  2664   - append all possible rule selections, but only use the first
  2665     success (no backtracking);
  2666   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2667   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2668   - added 'print_induct_rules' (covered by help item in recent Proof
  2669     General versions);
  2670   - moved induct/cases attributes to Pure, methods to Provers;
  2671   - generic method setup instantiated for FOL and HOL;
  2672 
  2673 * Pure: support multiple simultaneous goal statements, for example
  2674 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2675 meta-level mechanism, this acts as if several individual goals had
  2676 been stated separately; in particular common proof methods need to be
  2677 repeated in order to cover all claims; note that a single elimination
  2678 step is *not* sufficient to establish the two conjunctions, so this
  2679 fails:
  2680 
  2681   assume "A & B" then have A and B ..   (*".." fails*)
  2682 
  2683 better use "obtain" in situations as above; alternative refer to
  2684 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2685 
  2686 * Pure: proper integration with ``locales''; unlike the original
  2687 version by Florian Kammller, Isar locales package high-level proof
  2688 contexts rather than raw logical ones (e.g. we admit to include
  2689 attributes everywhere); operations on locales include merge and
  2690 rename; support for implicit arguments (``structures''); simultaneous
  2691 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2692 some examples;
  2693 
  2694 * Pure: the following commands have been ``localized'', supporting a
  2695 target locale specification "(in name)": 'lemma', 'theorem',
  2696 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2697 stored both within the locale and at the theory level (exported and
  2698 qualified by the locale name);
  2699 
  2700 * Pure: theory goals may now be specified in ``long'' form, with
  2701 ad-hoc contexts consisting of arbitrary locale elements. for example
  2702 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2703 definitions may be given, too); the result is a meta-level rule with
  2704 the context elements being discharged in the obvious way;
  2705 
  2706 * Pure: new proof command 'using' allows to augment currently used
  2707 facts after a goal statement ('using' is syntactically analogous to
  2708 'apply', but acts on the goal's facts only); this allows chained facts
  2709 to be separated into parts given before and after a claim, as in
  2710 ``from a and b have C using d and e <proof>'';
  2711 
  2712 * Pure: renamed "antecedent" case to "rule_context";
  2713 
  2714 * Pure: new 'judgment' command records explicit information about the
  2715 object-logic embedding (used by several tools internally); no longer
  2716 use hard-wired "Trueprop";
  2717 
  2718 * Pure: added 'corollary' command;
  2719 
  2720 * Pure: fixed 'token_translation' command;
  2721 
  2722 * Pure: removed obsolete 'exported' attribute;
  2723 
  2724 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2725 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2726 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2727 
  2728 * Pure: method 'atomize' presents local goal premises as object-level
  2729 statements (atomic meta-level propositions); setup controlled via
  2730 rewrite rules declarations of 'atomize' attribute; example
  2731 application: 'induct' method with proper rule statements in improper
  2732 proof *scripts*;
  2733 
  2734 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2735 now consider the syntactic context of assumptions, giving a better
  2736 chance to get type-inference of the arguments right (this is
  2737 especially important for locales);
  2738 
  2739 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2740 mode;
  2741 
  2742 * Pure/obtain: the formal conclusion "thesis", being marked as
  2743 ``internal'', may no longer be reference directly in the text;
  2744 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2745 situations;
  2746 
  2747 * Pure: generic 'sym' attribute which declares a rule both as pure
  2748 'elim?' and for the 'symmetric' operation;
  2749 
  2750 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2751 text; the fixed correlation with particular command syntax has been
  2752 discontinued;
  2753 
  2754 * Pure: new method 'rules' is particularly well-suited for proof
  2755 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2756 but often produces more compact proof terms with less detours;
  2757 
  2758 * Pure/Provers/classical: simplified integration with pure rule
  2759 attributes and methods; the classical "intro?/elim?/dest?"
  2760 declarations coincide with the pure ones; the "rule" method no longer
  2761 includes classically swapped intros; "intro" and "elim" methods no
  2762 longer pick rules from the context; also got rid of ML declarations
  2763 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2764 INCOMPATIBILITY;
  2765 
  2766 * Provers/classical: attribute 'swapped' produces classical inversions
  2767 of introduction rules;
  2768 
  2769 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2770 rules instead of full simplifier context; 'iff' attribute handles
  2771 conditional rules;
  2772 
  2773 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2774 
  2775 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2776 "(permissive)" option to recover old behavior;
  2777 
  2778 * HOL: 'inductive' no longer features separate (collective) attributes
  2779 for 'intros' (was found too confusing);
  2780 
  2781 * HOL: properly declared induction rules less_induct and
  2782 wf_induct_rule;
  2783 
  2784 
  2785 *** HOL ***
  2786 
  2787 * HOL: moved over to sane numeral syntax; the new policy is as
  2788 follows:
  2789 
  2790   - 0 and 1 are polymorphic constants, which are defined on any
  2791   numeric type (nat, int, real etc.);
  2792 
  2793   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2794   binary representation internally;
  2795 
  2796   - type nat has special constructor Suc, and generally prefers Suc 0
  2797   over 1::nat and Suc (Suc 0) over 2::nat;
  2798 
  2799 This change may cause significant problems of INCOMPATIBILITY; here
  2800 are some hints on converting existing sources:
  2801 
  2802   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2803   entities, so expressions involving "-" (unary or binary minus) need
  2804   to be spaced properly;
  2805 
  2806   - existing occurrences of "1" may need to be constraint "1::nat" or
  2807   even replaced by Suc 0; similar for old "2";
  2808 
  2809   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2810 
  2811   - remove all special provisions on numerals in proofs;
  2812 
  2813 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2814 representation (depends on bin_arith_simps in the default context);
  2815 
  2816 * HOL: symbolic syntax for x^2 (numeral 2);
  2817 
  2818 * HOL: the class of all HOL types is now called "type" rather than
  2819 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2820 in axclass/classes, instance/arities, and (usually rare) occurrences
  2821 in typings (of consts etc.); internally the class is called
  2822 "HOL.type", ML programs should refer to HOLogic.typeS;
  2823 
  2824 * HOL/record package improvements:
  2825   - new derived operations "fields" to build a partial record section,
  2826     "extend" to promote a fixed record to a record scheme, and
  2827     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2828     declared as simp by default;
  2829   - shared operations ("more", "fields", etc.) now need to be always
  2830     qualified) --- potential INCOMPATIBILITY;
  2831   - removed "make_scheme" operations (use "make" with "extend") --
  2832     INCOMPATIBILITY;
  2833   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2834   - provides cases/induct rules for use with corresponding Isar
  2835     methods (for concrete records, record schemes, concrete more
  2836     parts, and schematic more parts -- in that order);
  2837   - internal definitions directly based on a light-weight abstract
  2838     theory of product types over typedef rather than datatype;
  2839 
  2840 * HOL: generic code generator for generating executable ML code from
  2841 specifications; specific support for HOL constructs such as inductive
  2842 datatypes and sets, as well as recursive functions; can be invoked
  2843 via 'generate_code' theory section;
  2844 
  2845 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2846 
  2847 * HOL: consolidated and renamed several theories.  In particular:
  2848         Ord.thy has been absorbed into HOL.thy
  2849         String.thy has been absorbed into List.thy
  2850 
  2851 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2852 (beware of argument permutation!);
  2853 
  2854 * HOL: linorder_less_split superseded by linorder_cases;
  2855 
  2856 * HOL/List: "nodups" renamed to "distinct";
  2857 
  2858 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2859 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2860   - Ex_def has changed, now need to use some_eq_ex
  2861 
  2862 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2863 in this (rare) case use:
  2864 
  2865   delSWrapper "split_all_tac"
  2866   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2867 
  2868 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2869 MAY FAIL;
  2870 
  2871 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2872 Isabelle's type classes, ^ on functions and relations has too general
  2873 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2874 necessary to attach explicit type constraints;
  2875 
  2876 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2877 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2878 renamed accordingly (eg "compI" -> "rel_compI").
  2879 
  2880 * HOL: syntax translations now work properly with numerals and records
  2881 expressions;
  2882 
  2883 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2884 of "lam" -- INCOMPATIBILITY;
  2885 
  2886 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2887 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2888 renamed "Product_Type.unit";
  2889 
  2890 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2891 
  2892 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2893 the "cases" method);
  2894 
  2895 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2896 Florian Kammller);
  2897 
  2898 * HOL/IMP: updated and converted to new-style theory format; several
  2899 parts turned into readable document, with proper Isar proof texts and
  2900 some explanations (by Gerwin Klein);
  2901 
  2902 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2903 
  2904 * HOL-Hyperreal is now a logic image;
  2905 
  2906 
  2907 *** HOLCF ***
  2908 
  2909 * Isar: consts/constdefs supports mixfix syntax for continuous
  2910 operations;
  2911 
  2912 * Isar: domain package adapted to new-style theory format, e.g. see
  2913 HOLCF/ex/Dnat.thy;
  2914 
  2915 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2916 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2917 lift.induct_tac, always use UU instead of Undef;
  2918 
  2919 * HOLCF/IMP: updated and converted to new-style theory;
  2920 
  2921 
  2922 *** ZF ***
  2923 
  2924 * Isar: proper integration of logic-specific tools and packages,
  2925 including theory commands '(co)inductive', '(co)datatype',
  2926 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2927 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2928 
  2929 * theory Main no longer includes AC; for the Axiom of Choice, base
  2930 your theory on Main_ZFC;
  2931 
  2932 * the integer library now covers quotients and remainders, with many
  2933 laws relating division to addition, multiplication, etc.;
  2934 
  2935 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2936 typeless version of the formalism;
  2937 
  2938 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2939 format;
  2940 
  2941 * ZF/Induct: new directory for examples of inductive definitions,
  2942 including theory Multiset for multiset orderings; converted to
  2943 new-style theory format;
  2944 
  2945 * ZF: many new theorems about lists, ordinals, etc.;
  2946 
  2947 
  2948 *** General ***
  2949 
  2950 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2951 variable proof controls level of detail: 0 = no proofs (only oracle
  2952 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2953 also ref manual for further ML interfaces;
  2954 
  2955 * Pure/axclass: removed obsolete ML interface
  2956 goal_subclass/goal_arity;
  2957 
  2958 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2959 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2960 separate tokens, so expressions involving minus need to be spaced
  2961 properly;
  2962 
  2963 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2964 rather than "infixl" or "infixr";
  2965 
  2966 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2967 sort constraint specifications in type inference; e.g. "x::_::foo"
  2968 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2969 type variable);
  2970 
  2971 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2972 control output of nested => (types); the default behavior is
  2973 "type_brackets";
  2974 
  2975 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2976 tokens into AST constants;
  2977 
  2978 * Pure/syntax: prefer later declarations of translations and print
  2979 translation functions; potential INCOMPATIBILITY: need to reverse
  2980 multiple declarations for same syntax element constant;
  2981 
  2982 * Pure/show_hyps reset by default (in accordance to existing Isar
  2983 practice);
  2984 
  2985 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2986 addSafter;
  2987 
  2988 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2989 as well;
  2990 
  2991 * system: tested support for MacOS X; should be able to get Isabelle +
  2992 Proof General to work in a plain Terminal after installing Poly/ML
  2993 (e.g. from the Isabelle distribution area) and GNU bash alone
  2994 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2995 support requires further installations, e.g. from
  2996 http://fink.sourceforge.net/);
  2997 
  2998 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2999 
  3000 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3001 of 40 MB), cf. ML_OPTIONS;
  3002 
  3003 * system: Proof General keywords specification is now part of the
  3004 Isabelle distribution (see etc/isar-keywords.el);
  3005 
  3006 * system: support for persistent Proof General sessions (refrain from
  3007 outdating all loaded theories on startup); user may create writable
  3008 logic images like this: ``isabelle -q HOL Test'';
  3009 
  3010 * system: smart selection of Isabelle process versus Isabelle
  3011 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3012 run both "isabelle" and "Isabelle" even if file names are badly
  3013 damaged (executable inspects the case of the first letter of its own
  3014 name); added separate "isabelle-process" and "isabelle-interface";
  3015 
  3016 * system: refrain from any attempt at filtering input streams; no
  3017 longer support ``8bit'' encoding of old isabelle font, instead proper
  3018 iso-latin characters may now be used; the related isatools
  3019 "symbolinput" and "nonascii" have disappeared as well;
  3020 
  3021 * system: removed old "xterm" interface (the print modes "xterm" and
  3022 "xterm_color" are still available for direct use in a suitable
  3023 terminal);
  3024 
  3025 
  3026 
  3027 New in Isabelle99-2 (February 2001)
  3028 -----------------------------------
  3029 
  3030 *** Overview of INCOMPATIBILITIES ***
  3031 
  3032 * HOL: please note that theories in the Library and elsewhere often use the
  3033 new-style (Isar) format; to refer to their theorems in an ML script you must
  3034 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3035 
  3036 * HOL: inductive package no longer splits induction rule aggressively,
  3037 but only as far as specified by the introductions given; the old
  3038 format may be recovered via ML function complete_split_rule or attribute
  3039 'split_rule (complete)';
  3040 
  3041 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3042 gfp_Tarski to gfp_unfold;
  3043 
  3044 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3045 
  3046 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3047 relation); infix "^^" has been renamed "``"; infix "``" has been
  3048 renamed "`"; "univalent" has been renamed "single_valued";
  3049 
  3050 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3051 operation;
  3052 
  3053 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3054 
  3055 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3056 
  3057 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3058 consequence, it is no longer monotonic wrt. the local goal context
  3059 (which is now passed through the inductive cases);
  3060 
  3061 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3062 \<gg> to \<ggreater>;
  3063 
  3064 
  3065 *** Document preparation ***
  3066 
  3067 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3068 available: are "it" for near math-mode best-style output, "sl" for
  3069 slanted text style, and "tt" for plain type-writer; if no
  3070 \isabellestyle command is given, output is according to slanted
  3071 type-writer);
  3072 
  3073 * support sub/super scripts (for single symbols only), input syntax is
  3074 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3075 
  3076 * some more standard symbols; see Appendix A of the system manual for
  3077 the complete list of symbols defined in isabellesym.sty;
  3078 
  3079 * improved isabelle style files; more abstract symbol implementation
  3080 (should now use \isamath{...} and \isatext{...} in custom symbol
  3081 definitions);
  3082 
  3083 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3084 state; Note that presentation of goal states does not conform to
  3085 actual human-readable proof documents.  Please do not include goal
  3086 states into document output unless you really know what you are doing!
  3087 
  3088 * proper indentation of antiquoted output with proportional LaTeX
  3089 fonts;
  3090 
  3091 * no_document ML operator temporarily disables LaTeX document
  3092 generation;
  3093 
  3094 * isatool unsymbolize tunes sources for plain ASCII communication;
  3095 
  3096 
  3097 *** Isar ***
  3098 
  3099 * Pure: Isar now suffers initial goal statements to contain unbound
  3100 schematic variables (this does not conform to actual readable proof
  3101 documents, due to unpredictable outcome and non-compositional proof
  3102 checking); users who know what they are doing may use schematic goals
  3103 for Prolog-style synthesis of proven results;
  3104 
  3105 * Pure: assumption method (an implicit finishing) now handles actual
  3106 rules as well;
  3107 
  3108 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3109 initial goal, declare "that" only as Pure intro (only for single
  3110 steps); the "that" rule assumption may now be involved in implicit
  3111 finishing, thus ".." becomes a feasible for trivial obtains;
  3112 
  3113 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3114 instance proofs may be performed by "..";
  3115 
  3116 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3117 statements as well;
  3118 
  3119 * Pure: more robust selection of calculational rules;
  3120 
  3121 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3122 rule (as well as the assumption rule);
  3123 
  3124 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3125 lemmas, using the graph browser tool;
  3126 
  3127 * Pure: predict failure of "show" in interactive mode;
  3128 
  3129 * Pure: 'thms_containing' now takes actual terms as arguments;
  3130 
  3131 * HOL: improved method 'induct' --- now handles non-atomic goals
  3132 (potential INCOMPATIBILITY); tuned error handling;
  3133 
  3134 * HOL: cases and induct rules now provide explicit hints about the
  3135 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3136 any remaining facts are inserted into the goal verbatim;
  3137 
  3138 * HOL: local contexts (aka cases) may now contain term bindings as
  3139 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3140 the result to be shown in each case;
  3141 
  3142 * HOL: added 'recdef_tc' command;
  3143 
  3144 * isatool convert assists in eliminating legacy ML scripts;
  3145 
  3146 
  3147 *** HOL ***
  3148 
  3149 * HOL/Library: a collection of generic theories to be used together
  3150 with main HOL; the theory loader path already includes this directory
  3151 by default; the following existing theories have been moved here:
  3152 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3153 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3154 
  3155 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3156 modelling and verification task performed in Isabelle/HOL +
  3157 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3158 
  3159 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3160 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3161 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3162 'domain', this makes the theory consistent with mathematical
  3163 literature;
  3164 
  3165 * HOL basics: added overloaded operations "inverse" and "divide"
  3166 (infix "/"), syntax for generic "abs" operation, generic summation
  3167 operator \<Sum>;
  3168 
  3169 * HOL/typedef: simplified package, provide more useful rules (see also
  3170 HOL/subset.thy);
  3171 
  3172 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3173 now expressed as a proper nested rule (old-style tactic scripts may
  3174 require atomize_strip_tac to cope with non-atomic premises);
  3175 
  3176 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3177 to "split_conv" (old name still available for compatibility);
  3178 
  3179 * HOL: improved concrete syntax for strings (e.g. allows translation
  3180 rules with string literals);
  3181 
  3182 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3183  and Fleuriot's mechanization of analysis, including the transcendental
  3184  functions for the reals;
  3185 
  3186 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3187 
  3188 
  3189 *** CTT ***
  3190 
  3191 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3192 "lam" is displayed as TWO lambda-symbols
  3193 
  3194 * CTT: theory Main now available, containing everything (that is, Bool
  3195 and Arith);
  3196 
  3197 
  3198 *** General ***
  3199 
  3200 * Pure: the Simplifier has been implemented properly as a derived rule
  3201 outside of the actual kernel (at last!); the overall performance
  3202 penalty in practical applications is about 50%, while reliability of
  3203 the Isabelle inference kernel has been greatly improved;
  3204 
  3205 * print modes "brackets" and "no_brackets" control output of nested =>
  3206 (types) and ==> (props); the default behaviour is "brackets";
  3207 
  3208 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3209 as assumptions as well;
  3210 
  3211 * system: support Poly/ML 4.0;
  3212 
  3213 * system: isatool install handles KDE version 1 or 2;
  3214 
  3215 
  3216 
  3217 New in Isabelle99-1 (October 2000)
  3218 ----------------------------------
  3219 
  3220 *** Overview of INCOMPATIBILITIES ***
  3221 
  3222 * HOL: simplification of natural numbers is much changed; to partly
  3223 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3224 issue the following ML commands:
  3225 
  3226   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3227   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3228 
  3229 * HOL: simplification no longer dives into case-expressions; this is
  3230 controlled by "t.weak_case_cong" for each datatype t;
  3231 
  3232 * HOL: nat_less_induct renamed to less_induct;
  3233 
  3234 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3235 fixsome to patch .thy and .ML sources automatically;
  3236 
  3237   select_equality  -> some_equality
  3238   select_eq_Ex     -> some_eq_ex
  3239   selectI2EX       -> someI2_ex
  3240   selectI2         -> someI2
  3241   selectI          -> someI
  3242   select1_equality -> some1_equality
  3243   Eps_sym_eq       -> some_sym_eq_trivial
  3244   Eps_eq           -> some_eq_trivial
  3245 
  3246 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3247 
  3248 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3249 instead);
  3250 
  3251 * HOL: the recursion equations generated by 'recdef' are now called
  3252 f.simps instead of f.rules;
  3253 
  3254 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3255 
  3256 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3257 sometimes be needed;
  3258 
  3259 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3260 
  3261 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3262 
  3263 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3264 product is now "<*>" instead of "Times"; the lexicographic product is
  3265 now "<*lex*>" instead of "**";
  3266 
  3267 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3268 of main HOL, but was unused); better use HOL's datatype package;
  3269 
  3270 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3271 the old syntax may be recovered as follows:
  3272 
  3273   syntax (symbols)
  3274     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3275       (infixl "\\<oplus>" 100)
  3276 
  3277 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3278 
  3279 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3280 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3281 internally;
  3282 
  3283 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3284 changed from A/r to A//r;
  3285 
  3286 * ZF: new treatment of arithmetic (nat & int) may break some old
  3287 proofs;
  3288 
  3289 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3290 rulify -> rule_format, elimify -> elim_format, ...);
  3291 
  3292 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3293 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3294 should have to change intro!! to intro? only); replaced "delrule" by
  3295 "rule del";
  3296 
  3297 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3298 
  3299 * Provers: strengthened force_tac by using new first_best_tac;
  3300 
  3301 * LaTeX document preparation: several changes of isabelle.sty (see
  3302 lib/texinputs);
  3303 
  3304 
  3305 *** Document preparation ***
  3306 
  3307 * formal comments (text blocks etc.) in new-style theories may now
  3308 contain antiquotations of thm/prop/term/typ/text to be presented
  3309 according to latex print mode; concrete syntax is like this:
  3310 @{term[show_types] "f(x) = a + x"};
  3311 
  3312 * isatool mkdir provides easy setup of Isabelle session directories,
  3313 including proper document sources;
  3314 
  3315 * generated LaTeX sources are now deleted after successful run
  3316 (isatool document -c); may retain a copy somewhere else via -D option
  3317 of isatool usedir;
  3318 
  3319 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3320 style files, achieving self-contained LaTeX sources and simplifying
  3321 LaTeX debugging;
  3322 
  3323 * old-style theories now produce (crude) LaTeX output as well;
  3324 
  3325 * browser info session directories are now self-contained (may be put
  3326 on WWW server seperately); improved graphs of nested sessions; removed
  3327 graph for 'all sessions';
  3328 
  3329 * several improvements in isabelle style files; \isabellestyle{it}
  3330 produces fake math mode output; \isamarkupheader is now \section by
  3331 default; see lib/texinputs/isabelle.sty etc.;
  3332 
  3333 
  3334 *** Isar ***
  3335 
  3336 * Isar/Pure: local results and corresponding term bindings are now
  3337 subject to Hindley-Milner polymorphism (similar to ML); this
  3338 accommodates incremental type-inference very nicely;
  3339 
  3340 * Isar/Pure: new derived language element 'obtain' supports
  3341 generalized existence reasoning;
  3342 
  3343 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3344 support accumulation of results, without applying any rules yet;
  3345 useful to collect intermediate results without explicit name
  3346 references, and for use with transitivity rules with more than 2
  3347 premises;
  3348 
  3349 * Isar/Pure: scalable support for case-analysis type proofs: new
  3350 'case' language element refers to local contexts symbolically, as
  3351 produced by certain proof methods; internally, case names are attached
  3352 to theorems as "tags";
  3353 
  3354 * Isar/Pure: theory command 'hide' removes declarations from
  3355 class/type/const name spaces;
  3356 
  3357 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3358 indicate potential overloading;
  3359 
  3360 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3361 
  3362 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3363 "{a,b,c}" instead of {a,b,c};
  3364 
  3365 * Isar/Pure now provides its own version of intro/elim/dest
  3366 attributes; useful for building new logics, but beware of confusion
  3367 with the version in Provers/classical;
  3368 
  3369 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3370 case name 'antecedent';
  3371 
  3372 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3373 to the current context is now done automatically);
  3374 
  3375 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3376 for definining proof methods in ML;
  3377 
  3378 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3379 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3380 most cases, one should have to change intro!! to intro? only);
  3381 replaced "delrule" by "rule del";
  3382 
  3383 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3384 'symmetric' attribute (the latter supercedes [RS sym]);
  3385 
  3386 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3387 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3388 well (including splits);
  3389 
  3390 * Isar/Provers: Simplifier and Classical methods now support all kind
  3391 of modifiers used in the past, including 'cong', 'iff', etc.
  3392 
  3393 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3394 of Simplifier and Classical reasoner);
  3395 
  3396 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3397 now support named cases; major packages (inductive, datatype, primrec,
  3398 recdef) support case names and properly name parameters;
  3399 
  3400 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3401 monotonicity conditions are extracted to be proven at end of
  3402 calculations;
  3403 
  3404 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3405 method anyway;
  3406 
  3407 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3408 split_if split_if_asm; datatype package provides theorems foo.splits =
  3409 foo.split foo.split_asm for each datatype;
  3410 
  3411 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3412 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3413 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3414 use "(cases (simplified))" method in proper proof texts);
  3415 
  3416 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3417 
  3418 * Isar: names of theorems etc. may be natural numbers as well;
  3419 
  3420 * Isar: 'pr' command: optional arguments for goals_limit and
  3421 ProofContext.prems_limit; no longer prints theory contexts, but only
  3422 proof states;
  3423 
  3424 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3425 additional print modes to be specified; e.g. "pr(latex)" will print
  3426 proof state according to the Isabelle LaTeX style;
  3427 
  3428 * Isar: improved support for emulating tactic scripts, including proof
  3429 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3430 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3431 (for HOL datatypes);
  3432 
  3433 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3434 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3435 'proof method scripts' have to be in depth-first order;
  3436 
  3437 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3438 
  3439 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3440 should instead use individual commands for printing items
  3441 (print_commands, print_methods etc.);
  3442 
  3443 * Isar: added 'nothing' --- the empty list of theorems;
  3444 
  3445 
  3446 *** HOL ***
  3447 
  3448 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3449 corresponding virtual machine and a specification of its bytecode
  3450 verifier and a lightweight bytecode verifier, including proofs of
  3451 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3452 Cornelia Pusch (see also the homepage of project Bali at
  3453 http://isabelle.in.tum.de/Bali/);
  3454 
  3455 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3456 Clemens Ballarin;
  3457 
  3458 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3459 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3460 Rasmussen;
  3461 
  3462 * HOL/Lattice: fundamental concepts of lattice theory and order
  3463 structures, including duals, properties of bounds versus algebraic
  3464 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3465 Theorem for complete lattices etc.; may also serve as a demonstration
  3466 for abstract algebraic reasoning using axiomatic type classes, and
  3467 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3468 
  3469 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3470 von Oheimb;
  3471 
  3472 * HOL/IMPP: extension of IMP with local variables and mutually
  3473 recursive procedures, by David von Oheimb;
  3474 
  3475 * HOL/Lambda: converted into new-style theory and document;
  3476 
  3477 * HOL/ex/Multiquote: example of multiple nested quotations and
  3478 anti-quotations -- basically a generalized version of de-Bruijn
  3479 representation; very useful in avoiding lifting of operations;
  3480 
  3481 * HOL/record: added general record equality rule to simpset; fixed
  3482 select-update simplification procedure to handle extended records as
  3483 well; admit "r" as field name;
  3484 
  3485 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3486 other numeric types and also as the identity of groups, rings, etc.;
  3487 
  3488 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3489 Types nat and int belong to this axclass;
  3490 
  3491 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3492    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3493    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3494   two terms #m*u and #n*u are replaced by #(m+n)*u
  3495     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3496   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3497     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3498 
  3499 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3500 powerful prover for predicate logic but knows nothing of clasets; see
  3501 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3502 
  3503 * HOL: new version of "case_tac" subsumes both boolean case split and
  3504 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3505 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3506 
  3507 * HOL: simplification no longer dives into case-expressions: only the
  3508 selector expression is simplified, but not the remaining arms; to
  3509 enable full simplification of case-expressions for datatype t, you may
  3510 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3511 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3512 
  3513 * HOL/recdef: the recursion equations generated by 'recdef' for
  3514 function 'f' are now called f.simps instead of f.rules; if all
  3515 termination conditions are proved automatically, these simplification
  3516 rules are added to the simpset, as in primrec; rules may be named
  3517 individually as well, resulting in a separate list of theorems for
  3518 each equation;
  3519 
  3520 * HOL/While is a new theory that provides a while-combinator. It
  3521 permits the definition of tail-recursive functions without the
  3522 provision of a termination measure. The latter is necessary once the
  3523 invariant proof rule for while is applied.
  3524 
  3525 * HOL: new (overloaded) notation for the set of elements below/above
  3526 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3527 
  3528 * HOL: theorems impI, allI, ballI bound as "strip";
  3529 
  3530 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3531 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3532 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3533 
  3534 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3535 
  3536 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3537 main HOL, but was unused);
  3538 
  3539 * HOL: fewer consts declared as global (e.g. have to refer to
  3540 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3541 
  3542 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3543 in case of overlap with user translations (e.g. judgements over
  3544 tuples); (note that the underlying logical represenation is still
  3545 bogus);
  3546 
  3547 
  3548 *** ZF ***
  3549 
  3550 * ZF: simplification automatically cancels common terms in arithmetic
  3551 expressions over nat and int;
  3552 
  3553 * ZF: new treatment of nat to minimize type-checking: all operators
  3554 coerce their operands to a natural number using the function natify,
  3555 making the algebraic laws unconditional;
  3556 
  3557 * ZF: as above, for int: operators coerce their operands to an integer
  3558 using the function intify;
  3559 
  3560 * ZF: the integer library now contains many of the usual laws for the
  3561 orderings, including $<=, and monotonicity laws for $+ and $*;
  3562 
  3563 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3564 simplification;
  3565 
  3566 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3567 to the simplifier and classical reasoner simultaneously;
  3568 
  3569 
  3570 *** General ***
  3571 
  3572 * Provers: blast_tac now handles actual object-logic rules as
  3573 assumptions; note that auto_tac uses blast_tac internally as well;
  3574 
  3575 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3576 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3577 
  3578 * Provers: delrules now handles destruct rules as well (no longer need
  3579 explicit make_elim);
  3580 
  3581 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3582   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3583 use instead the strong form,
  3584   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3585 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3586 from destruct-rules;
  3587 
  3588 * Provers: Simplifier.easy_setup provides a fast path to basic
  3589 Simplifier setup for new object-logics;
  3590 
  3591 * Pure: AST translation rules no longer require constant head on LHS;
  3592 
  3593 * Pure: improved name spaces: ambiguous output is qualified; support
  3594 for hiding of names;
  3595 
  3596 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3597 XSYMBOL_HOME; no longer need to do manual configuration in most
  3598 situations;
  3599 
  3600 * system: compression of ML heaps images may now be controlled via -c
  3601 option of isabelle and isatool usedir (currently only observed by
  3602 Poly/ML);
  3603 
  3604 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3605 useful for remote X11);
  3606 
  3607 * system: provide TAGS file for Isabelle sources;
  3608 
  3609 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3610 order;
  3611 
  3612 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3613 timing flag supersedes proof_timing and Toplevel.trace;
  3614 
  3615 * ML: new combinators |>> and |>>> for incremental transformations
  3616 with secondary results (e.g. certain theory extensions):
  3617 
  3618 * ML: PureThy.add_defs gets additional argument to indicate potential
  3619 overloading (usually false);
  3620 
  3621 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3622 results;
  3623 
  3624 
  3625 
  3626 New in Isabelle99 (October 1999)
  3627 --------------------------------
  3628 
  3629 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3630 
  3631 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3632 are no longer simplified.  (This allows the simplifier to unfold recursive
  3633 functional programs.)  To restore the old behaviour, declare
  3634 
  3635     Delcongs [if_weak_cong];
  3636 
  3637 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3638 complement;
  3639 
  3640 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3641 
  3642 * HOL/datatype: mutual_induct_tac no longer exists --
  3643   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3644 
  3645 * HOL/typedef: fixed type inference for representing set; type
  3646 arguments now have to occur explicitly on the rhs as type constraints;
  3647 
  3648 * ZF: The con_defs part of an inductive definition may no longer refer
  3649 to constants declared in the same theory;
  3650 
  3651 * HOL, ZF: the function mk_cases, generated by the inductive
  3652 definition package, has lost an argument.  To simplify its result, it
  3653 uses the default simpset instead of a supplied list of theorems.
  3654 
  3655 * HOL/List: the constructors of type list are now Nil and Cons;
  3656 
  3657 * Simplifier: the type of the infix ML functions
  3658         setSSolver addSSolver setSolver addSolver
  3659 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3660 for packaging solvers. A solver is created via
  3661         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3662 where the string argument is only a comment.
  3663 
  3664 
  3665 *** Proof tools ***
  3666 
  3667 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3668 decision procedure for linear arithmetic. Currently it is used for
  3669 types `nat', `int', and `real' in HOL (see below); it can, should and
  3670 will be instantiated for other types and logics as well.
  3671 
  3672 * The simplifier now accepts rewrite rules with flexible heads, eg
  3673      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3674   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3675   matching.
  3676 
  3677 
  3678 *** General ***
  3679 
  3680 * New Isabelle/Isar subsystem provides an alternative to traditional
  3681 tactical theorem proving; together with the ProofGeneral/isar user
  3682 interface it offers an interactive environment for developing human
  3683 readable proof documents (Isar == Intelligible semi-automated
  3684 reasoning); for further information see isatool doc isar-ref,
  3685 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3686 
  3687 * improved and simplified presentation of theories: better HTML markup
  3688 (including colors), graph views in several sizes; isatool usedir now
  3689 provides a proper interface for user theories (via -P option); actual
  3690 document preparation based on (PDF)LaTeX is available as well (for
  3691 new-style theories only); see isatool doc system for more information;
  3692 
  3693 * native support for Proof General, both for classic Isabelle and
  3694 Isabelle/Isar;
  3695 
  3696 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3697 using the graph browser tool;
  3698 
  3699 * Isabelle manuals now also available as PDF;
  3700 
  3701 * theory loader rewritten from scratch (may not be fully
  3702 bug-compatible); old loadpath variable has been replaced by show_path,
  3703 add_path, del_path, reset_path functions; new operations such as
  3704 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3705 isatool doc ref);
  3706 
  3707 * improved isatool install: option -k creates KDE application icon,
  3708 option -p DIR installs standalone binaries;
  3709 
  3710 * added ML_PLATFORM setting (useful for cross-platform installations);
  3711 more robust handling of platform specific ML images for SML/NJ;
  3712 
  3713 * the settings environment is now statically scoped, i.e. it is never
  3714 created again in sub-processes invoked from isabelle, isatool, or
  3715 Isabelle;
  3716 
  3717 * path element specification '~~' refers to '$ISABELLE_HOME';
  3718 
  3719 * in locales, the "assumes" and "defines" parts may be omitted if
  3720 empty;
  3721 
  3722 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3723 long arrows);
  3724 
  3725 * new print_mode "HTML";
  3726 
  3727 * new flag show_tags controls display of tags of theorems (which are
  3728 basically just comments that may be attached by some tools);
  3729 
  3730 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3731 mode and goal output format:
  3732 
  3733 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3734 244c244
  3735 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3736 ---
  3737 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3738 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3739 181c181
  3740 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3741 ---
  3742 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3743 
  3744 * function bind_thms stores lists of theorems (cf. bind_thm);
  3745 
  3746 * new shorthand tactics ftac, eatac, datac, fatac;
  3747 
  3748 * qed (and friends) now accept "" as result name; in that case the
  3749 theorem is not stored, but proper checks and presentation of the
  3750 result still apply;
  3751 
  3752 * theorem database now also indexes constants "Trueprop", "all",
  3753 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3754 
  3755 
  3756 *** HOL ***
  3757 
  3758 ** HOL arithmetic **
  3759 
  3760 * There are now decision procedures for linear arithmetic over nat and
  3761 int:
  3762 
  3763 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3764 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3765 are treated as atomic; subformulae not involving type `nat' or `int'
  3766 are ignored; quantified subformulae are ignored unless they are
  3767 positive universal or negative existential. The tactic has to be
  3768 invoked by hand and can be a little bit slow. In particular, the
  3769 running time is exponential in the number of occurrences of `min' and
  3770 `max', and `-' on `nat'.
  3771 
  3772 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3773 (negated) (in)equalities among the premises and the conclusion into
  3774 account (i.e. no compound formulae) and does not know about `min' and
  3775 `max', and `-' on `nat'. It is fast and is used automatically by the
  3776 simplifier.
  3777 
  3778 NB: At the moment, these decision procedures do not cope with mixed
  3779 nat/int formulae where the two parts interact, such as `m < n ==>
  3780 int(m) < int(n)'.
  3781 
  3782 * HOL/Numeral provides a generic theory of numerals (encoded
  3783 efficiently as bit strings); setup for types nat/int/real is in place;
  3784 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3785 int, existing theories and proof scripts may require a few additional
  3786 type constraints;
  3787 
  3788 * integer division and remainder can now be performed on constant
  3789 arguments;
  3790 
  3791 * many properties of integer multiplication, division and remainder
  3792 are now available;
  3793 
  3794 * An interface to the Stanford Validity Checker (SVC) is available through the
  3795 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3796 are proved automatically.  SVC must be installed separately, and its results
  3797 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3798 invocation of the underlying oracle).  For SVC see
  3799   http://verify.stanford.edu/SVC
  3800 
  3801 * IsaMakefile: the HOL-Real target now builds an actual image;
  3802 
  3803 
  3804 ** HOL misc **
  3805 
  3806 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3807 (in Isabelle/Isar) -- by Gertrud Bauer;
  3808 
  3809 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3810 analysis for assembly languages with subtypes;
  3811 
  3812 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3813 -- avoids syntactic ambiguities and treats state, transition, and
  3814 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3815 changed syntax and (many) tactics;
  3816 
  3817 * HOL/inductive: Now also handles more general introduction rules such
  3818   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3819   theorems are now maintained within the theory (maintained via the
  3820   "mono" attribute);
  3821 
  3822 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3823   (using function types) such as
  3824 
  3825   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3826 
  3827 * HOL/record: record_simproc (part of the default simpset) takes care
  3828 of selectors applied to updated records; record_split_tac is no longer
  3829 part of the default claset; update_defs may now be removed from the
  3830 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3831 
  3832   claset_ref () := claset() addSWrapper record_split_wrapper;
  3833   Delsimprocs [record_simproc]
  3834 
  3835 * HOL/typedef: fixed type inference for representing set; type
  3836 arguments now have to occur explicitly on the rhs as type constraints;
  3837 
  3838 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3839 names rather than an ML expression;
  3840 
  3841 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3842 supplied later.  Program schemes can be defined, such as
  3843     "While B C s = (if B s then While B C (C s) else s)"
  3844 where the well-founded relation can be chosen after B and C have been given.
  3845 
  3846 * HOL/List: the constructors of type list are now Nil and Cons;
  3847 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3848 course, ML tools referring to List.list.op # etc. have to be adapted;
  3849 
  3850 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3851 disabled by default; run isabelle with option -m HOL to get back to
  3852 the original Gordon/HOL-style output;
  3853 
  3854 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3855 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3856 
  3857 * HOL basic syntax simplified (more orthogonal): all variants of
  3858 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3859 Eps operator is provided as well: "SOME x. P[x]";
  3860 
  3861 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3862 
  3863 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3864 thus available for user theories;
  3865 
  3866 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3867 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3868 time;
  3869 
  3870 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3871 several times and then mp;
  3872 
  3873 
  3874 *** LK ***
  3875 
  3876 * the notation <<...>> is now available as a notation for sequences of
  3877 formulas;
  3878 
  3879 * the simplifier is now installed
  3880 
  3881 * the axiom system has been generalized (thanks to Soren Heilmann)
  3882 
  3883 * the classical reasoner now has a default rule database
  3884 
  3885 
  3886 *** ZF ***
  3887 
  3888 * new primrec section allows primitive recursive functions to be given
  3889 directly (as in HOL) over datatypes and the natural numbers;
  3890 
  3891 * new tactics induct_tac and exhaust_tac for induction (or case
  3892 analysis) over datatypes and the natural numbers;
  3893 
  3894 * the datatype declaration of type T now defines the recursor T_rec;
  3895 
  3896 * simplification automatically does freeness reasoning for datatype
  3897 constructors;
  3898 
  3899 * automatic type-inference, with AddTCs command to insert new
  3900 type-checking rules;
  3901 
  3902 * datatype introduction rules are now added as Safe Introduction rules
  3903 to the claset;
  3904 
  3905 * the syntax "if P then x else y" is now available in addition to
  3906 if(P,x,y);
  3907 
  3908 
  3909 *** Internal programming interfaces ***
  3910 
  3911 * tuned simplifier trace output; new flag debug_simp;
  3912 
  3913 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3914 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3915 
  3916 * AxClass.axclass_tac lost the theory argument;
  3917 
  3918 * tuned current_goals_markers semantics: begin / end goal avoids
  3919 printing empty lines;
  3920 
  3921 * removed prs and prs_fn hook, which was broken because it did not
  3922 include \n in its semantics, forcing writeln to add one
  3923 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3924 string -> unit if you really want to output text without newline;
  3925 
  3926 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3927 plain output, interface builders may have to enable 'isabelle_font'
  3928 mode to get Isabelle font glyphs as before;
  3929 
  3930 * refined token_translation interface; INCOMPATIBILITY: output length
  3931 now of type real instead of int;
  3932 
  3933 * theory loader actions may be traced via new ThyInfo.add_hook
  3934 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3935 your own database of information attached to *whole* theories -- as
  3936 opposed to intra-theory data slots offered via TheoryDataFun;
  3937 
  3938 * proper handling of dangling sort hypotheses (at last!);
  3939 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3940 extra sort hypotheses that can be witnessed from the type signature;
  3941 the force_strip_shyps flag is gone, any remaining shyps are simply
  3942 left in the theorem (with a warning issued by strip_shyps_warning);
  3943 
  3944 
  3945 
  3946 New in Isabelle98-1 (October 1998)
  3947 ----------------------------------
  3948 
  3949 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3950 
  3951 * several changes of automated proof tools;
  3952 
  3953 * HOL: major changes to the inductive and datatype packages, including
  3954 some minor incompatibilities of theory syntax;
  3955 
  3956 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3957 called `inj_on';
  3958 
  3959 * HOL: removed duplicate thms in Arith:
  3960   less_imp_add_less  should be replaced by  trans_less_add1
  3961   le_imp_add_le      should be replaced by  trans_le_add1
  3962 
  3963 * HOL: unary minus is now overloaded (new type constraints may be
  3964 required);
  3965 
  3966 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3967 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3968 now taken as an integer constant.
  3969 
  3970 * Pure: ML function 'theory_of' renamed to 'theory';
  3971 
  3972 
  3973 *** Proof tools ***
  3974 
  3975 * Simplifier:
  3976   1. Asm_full_simp_tac is now more aggressive.
  3977      1. It will sometimes reorient premises if that increases their power to
  3978         simplify.
  3979      2. It does no longer proceed strictly from left to right but may also
  3980         rotate premises to achieve further simplification.
  3981      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3982      old Asm_full_simp_tac in that it does not rotate premises.
  3983   2. The simplifier now knows a little bit about nat-arithmetic.
  3984 
  3985 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3986 allows for selected deletion of wrappers, by introduction of names for
  3987 wrapper functionals.  This implies that addbefore, addSbefore,
  3988 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3989 and that adding two tactics with the same name overwrites the first
  3990 one (emitting a warning).
  3991   type wrapper = (int -> tactic) -> (int -> tactic)
  3992   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3993   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3994   delWrapper, delSWrapper: claset *  string            -> claset
  3995   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3996 
  3997 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3998 semantics; addbefore now affects only the unsafe part of step_tac
  3999 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4000 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4001 by Force_tac;
  4002 
  4003 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4004 compWrapper; added safe wrapper (and access functions for it);
  4005 
  4006 * HOL/split_all_tac is now much faster and fails if there is nothing
  4007 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4008 and the names of the automatically generated variables have changed.
  4009 split_all_tac has moved within claset() from unsafe wrappers to safe
  4010 wrappers, which means that !!-bound variables are split much more
  4011 aggressively, and safe_tac and clarify_tac now split such variables.
  4012 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4013 Note: the same holds for record_split_tac, which does the job of
  4014 split_all_tac for record fields.
  4015 
  4016 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4017 permanently to the default simpset using Addsplits just like
  4018 Addsimps. They can be removed via Delsplits just like
  4019 Delsimps. Lower-case versions are also available.
  4020 
  4021 * HOL/Simplifier: The rule split_if is now part of the default
  4022 simpset. This means that the simplifier will eliminate all occurrences
  4023 of if-then-else in the conclusion of a goal. To prevent this, you can
  4024 either remove split_if completely from the default simpset by
  4025 `Delsplits [split_if]' or remove it in a specific call of the
  4026 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4027 other case splitting rules to/from the default simpset: every datatype
  4028 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4029 t is the name of the datatype).
  4030 
  4031 * Classical reasoner / Simplifier combination: new force_tac (and
  4032 derivatives Force_tac, force) combines rewriting and classical
  4033 reasoning (and whatever other tools) similarly to auto_tac, but is
  4034 aimed to solve the given subgoal completely.
  4035 
  4036 
  4037 *** General ***
  4038 
  4039 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4040 and `goalw': the theory is no longer needed as an explicit argument -
  4041 the current theory context is used; assumptions are no longer returned
  4042 at the ML-level unless one of them starts with ==> or !!; it is
  4043 recommended to convert to these new commands using isatool fixgoal
  4044 (backup your sources first!);
  4045 
  4046 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4047 the current theory context, and 'theory' to lookup stored theories;
  4048 
  4049 * new theory section 'locale' for declaring constants, assumptions and
  4050 definitions that have local scope;
  4051 
  4052 * new theory section 'nonterminals' for purely syntactic types;
  4053 
  4054 * new theory section 'setup' for generic ML setup functions
  4055 (e.g. package initialization);
  4056 
  4057 * the distribution now includes Isabelle icons: see
  4058 lib/logo/isabelle-{small,tiny}.xpm;
  4059 
  4060 * isatool install - install binaries with absolute references to
  4061 ISABELLE_HOME/bin;
  4062 
  4063 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4064 
  4065 * print mode 'emacs' reserved for Isamode;
  4066 
  4067 * support multiple print (ast) translations per constant name;
  4068 
  4069 * theorems involving oracles are now printed with a suffixed [!];
  4070 
  4071 
  4072 *** HOL ***
  4073 
  4074 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4075 
  4076 * HOL/inductive package reorganized and improved: now supports mutual
  4077 definitions such as
  4078 
  4079   inductive EVEN ODD
  4080     intrs
  4081       null "0 : EVEN"
  4082       oddI "n : EVEN ==> Suc n : ODD"
  4083       evenI "n : ODD ==> Suc n : EVEN"
  4084 
  4085 new theorem list "elims" contains an elimination rule for each of the
  4086 recursive sets; inductive definitions now handle disjunctive premises
  4087 correctly (also ZF);
  4088 
  4089 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4090 "mutual_induct" no longer exists - the induction rule is always
  4091 contained in "induct";
  4092 
  4093 
  4094 * HOL/datatype package re-implemented and greatly improved: now
  4095 supports mutually recursive datatypes such as
  4096 
  4097   datatype
  4098     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4099             | SUM ('a aexp) ('a aexp)
  4100             | DIFF ('a aexp) ('a aexp)
  4101             | NUM 'a
  4102   and
  4103     'a bexp = LESS ('a aexp) ('a aexp)
  4104             | AND ('a bexp) ('a bexp)
  4105             | OR ('a bexp) ('a bexp)
  4106 
  4107 as well as indirectly recursive datatypes such as
  4108 
  4109   datatype
  4110     ('a, 'b) term = Var 'a
  4111                   | App 'b ((('a, 'b) term) list)
  4112 
  4113 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4114 induction on mutually / indirectly recursive datatypes.
  4115 
  4116 Primrec equations are now stored in theory and can be accessed via
  4117 <function_name>.simps.
  4118 
  4119 INCOMPATIBILITIES:
  4120 
  4121   - Theories using datatypes must now have theory Datatype as an
  4122     ancestor.
  4123   - The specific <typename>.induct_tac no longer exists - use the
  4124     generic induct_tac instead.
  4125   - natE has been renamed to nat.exhaust - use exhaust_tac
  4126     instead of res_inst_tac ... natE. Note that the variable
  4127     names in nat.exhaust differ from the names in natE, this
  4128     may cause some "fragile" proofs to fail.
  4129   - The theorems split_<typename>_case and split_<typename>_case_asm
  4130     have been renamed to <typename>.split and <typename>.split_asm.
  4131   - Since default sorts of type variables are now handled correctly,
  4132     some datatype definitions may have to be annotated with explicit
  4133     sort constraints.
  4134   - Primrec definitions no longer require function name and type
  4135     of recursive argument.
  4136 
  4137 Consider using isatool fixdatatype to adapt your theories and proof
  4138 scripts to the new package (backup your sources first!).
  4139 
  4140 
  4141 * HOL/record package: considerably improved implementation; now
  4142 includes concrete syntax for record types, terms, updates; theorems
  4143 for surjective pairing and splitting !!-bound record variables; proof
  4144 support is as follows:
  4145 
  4146   1) standard conversions (selectors or updates applied to record
  4147 constructor terms) are part of the standard simpset;
  4148 
  4149   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4150 made part of standard simpset and claset via addIffs;
  4151 
  4152   3) a tactic for record field splitting (record_split_tac) is part of
  4153 the standard claset (addSWrapper);
  4154 
  4155 To get a better idea about these rules you may retrieve them via
  4156 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4157 the name of your record type.
  4158 
  4159 The split tactic 3) conceptually simplifies by the following rule:
  4160 
  4161   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4162 
  4163 Thus any record variable that is bound by meta-all will automatically
  4164 blow up into some record constructor term, consequently the
  4165 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4166 solve record problems automatically.
  4167 
  4168 
  4169 * reorganized the main HOL image: HOL/Integ and String loaded by
  4170 default; theory Main includes everything;
  4171 
  4172 * automatic simplification of integer sums and comparisons, using cancellation;
  4173 
  4174 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4175 
  4176 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4177 
  4178 * many new identities for unions, intersections, set difference, etc.;
  4179 
  4180 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4181 called split_if, split_split, split_sum_case and split_nat_case (to go
  4182 with add/delsplits);
  4183 
  4184 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4185 (?x::unit) = (); this is made part of the default simpset, which COULD
  4186 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4187 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4188 unit_abs_eta_conv is added in order to counter the effect of
  4189 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4190 %u.f();
  4191 
  4192 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4193 makes more sense);
  4194 
  4195 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4196   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4197   disjointness reasoning but breaking a few old proofs.
  4198 
  4199 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4200 to 'converse' from 'inverse' (for compatibility with ZF and some
  4201 literature);
  4202 
  4203 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4204 the well-founded relation;
  4205 
  4206 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4207     Compl A.  The "Compl" syntax remains available as input syntax for this
  4208     release ONLY.
  4209 
  4210 * HOL/Update: new theory of function updates:
  4211     f(a:=b) == %x. if x=a then b else f x
  4212 may also be iterated as in f(a:=b,c:=d,...);
  4213 
  4214 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4215 
  4216 * HOL/List:
  4217   - new function list_update written xs[i:=v] that updates the i-th
  4218     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4219   - new function `upt' written [i..j(] which generates the list
  4220     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4221     bound write [i..j], which is a shorthand for [i..j+1(].
  4222   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4223 
  4224 * HOL/Arith:
  4225   - removed 'pred' (predecessor) function;
  4226   - generalized some theorems about n-1;
  4227   - many new laws about "div" and "mod";
  4228   - new laws about greatest common divisors (see theory ex/Primes);
  4229 
  4230 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4231 instead of "inverse";
  4232 
  4233 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4234   of the multiset ordering;
  4235 
  4236 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4237   (not included by default);
  4238 
  4239 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4240 
  4241 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4242   programs, i.e. different program variables may have different types.
  4243 
  4244 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4245   [previously, this check worked only if the rewrite rule was unconditional]
  4246   Now rew can involve either definitions or equalities (either == or =).
  4247 
  4248 
  4249 *** ZF ***
  4250 
  4251 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4252   only the theorems proved on ZF.ML;
  4253 
  4254 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4255   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4256   disjointness reasoning but breaking a few old proofs.
  4257 
  4258 * ZF/Update: new theory of function updates
  4259     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4260   may also be iterated as in f(a:=b,c:=d,...);
  4261 
  4262 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4263 
  4264 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4265   [previously, this check worked only if the rewrite rule was unconditional]
  4266   Now rew can involve either definitions or equalities (either == or =).
  4267 
  4268 * case_tac provided for compatibility with HOL
  4269     (like the old excluded_middle_tac, but with subgoals swapped)
  4270 
  4271 
  4272 *** Internal programming interfaces ***
  4273 
  4274 * Pure: several new basic modules made available for general use, see
  4275 also src/Pure/README;
  4276 
  4277 * improved the theory data mechanism to support encapsulation (data
  4278 kind name replaced by private Object.kind, acting as authorization
  4279 key); new type-safe user interface via functor TheoryDataFun; generic
  4280 print_data function becomes basically useless;
  4281 
  4282 * removed global_names compatibility flag -- all theory declarations
  4283 are qualified by default;
  4284 
  4285 * module Pure/Syntax now offers quote / antiquote translation
  4286 functions (useful for Hoare logic etc. with implicit dependencies);
  4287 see HOL/ex/Antiquote for an example use;
  4288 
  4289 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4290 cterm -> thm;
  4291 
  4292 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4293 subgoal;
  4294 
  4295 * Display.print_goals function moved to Locale.print_goals;
  4296 
  4297 * standard print function for goals supports current_goals_markers
  4298 variable for marking begin of proof, end of proof, start of goal; the
  4299 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4300 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4301 for example;
  4302 
  4303 
  4304 
  4305 New in Isabelle98 (January 1998)
  4306 --------------------------------
  4307 
  4308 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4309 
  4310 * changed lexical syntax of terms / types: dots made part of long
  4311 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4312 
  4313 * simpset (and claset) reference variable replaced by functions
  4314 simpset / simpset_ref;
  4315 
  4316 * no longer supports theory aliases (via merge) and non-trivial
  4317 implicit merge of thms' signatures;
  4318 
  4319 * most internal names of constants changed due to qualified names;
  4320 
  4321 * changed Pure/Sequence interface (see Pure/seq.ML);
  4322 
  4323 
  4324 *** General Changes ***
  4325 
  4326 * hierachically structured name spaces (for consts, types, axms, thms
  4327 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4328 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4329 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4330 long_names for fully qualified output names; NOTE: ML programs
  4331 (special tactics, packages etc.) referring to internal names may have
  4332 to be adapted to cope with fully qualified names; in case of severe
  4333 backward campatibility problems try setting 'global_names' at compile
  4334 time to have enrything declared within a flat name space; one may also
  4335 fine tune name declarations in theories via the 'global' and 'local'
  4336 section;
  4337 
  4338 * reimplemented the implicit simpset and claset using the new anytype
  4339 data filed in signatures; references simpset:simpset ref etc. are
  4340 replaced by functions simpset:unit->simpset and
  4341 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4342 to patch your ML files accordingly;
  4343 
  4344 * HTML output now includes theory graph data for display with Java
  4345 applet or isatool browser; data generated automatically via isatool
  4346 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4347 
  4348 * defs may now be conditional; improved rewrite_goals_tac to handle
  4349 conditional equations;
  4350 
  4351 * defs now admits additional type arguments, using TYPE('a) syntax;
  4352 
  4353 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4354 creates a new theory node; implicit merge of thms' signatures is
  4355 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4356 transfer:theory->thm->thm in (rare) cases;
  4357 
  4358 * improved handling of draft signatures / theories; draft thms (and
  4359 ctyps, cterms) are automatically promoted to real ones;
  4360 
  4361 * slightly changed interfaces for oracles: admit many per theory, named
  4362 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4363 
  4364 * print_goals: optional output of const types (set show_consts and
  4365 show_types);
  4366 
  4367 * improved output of warnings (###) and errors (***);
  4368 
  4369 * subgoal_tac displays a warning if the new subgoal has type variables;
  4370 
  4371 * removed old README and Makefiles;
  4372 
  4373 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4374 
  4375 * removed obsolete init_pps and init_database;
  4376 
  4377 * deleted the obsolete tactical STATE, which was declared by
  4378     fun STATE tacfun st = tacfun st st;
  4379 
  4380 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4381 (which abbreviates $HOME);
  4382 
  4383 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4384 use isatool fixseq to adapt your ML programs (this works for fully
  4385 qualified references to the Sequence structure only!);
  4386 
  4387 * use_thy no longer requires writable current directory; it always
  4388 reloads .ML *and* .thy file, if either one is out of date;
  4389 
  4390 
  4391 *** Classical Reasoner ***
  4392 
  4393 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4394 tactics that use classical reasoning to simplify a subgoal without
  4395 splitting it into several subgoals;
  4396 
  4397 * Safe_tac: like safe_tac but uses the default claset;
  4398 
  4399 
  4400 *** Simplifier ***
  4401 
  4402 * added simplification meta rules:
  4403     (asm_)(full_)simplify: simpset -> thm -> thm;
  4404 
  4405 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4406 logics (again);
  4407 
  4408 * added prems argument to simplification procedures;
  4409 
  4410 * HOL, FOL, ZF: added infix function `addsplits':
  4411   instead of `<simpset> setloop (split_tac <thms>)'
  4412   you can simply write `<simpset> addsplits <thms>'
  4413 
  4414 
  4415 *** Syntax ***
  4416 
  4417 * TYPE('a) syntax for type reflection terms;
  4418 
  4419 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4420 
  4421 * pretty printer: changed order of mixfix annotation preference (again!);
  4422 
  4423 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4424 
  4425 
  4426 *** HOL ***
  4427 
  4428 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4429   with `addloop' of the simplifier to faciliate case splitting in premises.
  4430 
  4431 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4432 
  4433 * HOL/Auth: new protocol proofs including some for the Internet
  4434   protocol TLS;
  4435 
  4436 * HOL/Map: new theory of `maps' a la VDM;
  4437 
  4438 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4439 cancelling out common nat summands from =, <, <= (in)equalities, or
  4440 differences; simplification procedures nat_cancel_factor for
  4441 cancelling common factor from =, <, <= (in)equalities over natural
  4442 sums; nat_cancel contains both kinds of procedures, it is installed by
  4443 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4444 
  4445 * HOL/simplifier: terms of the form
  4446   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4447   are rewritten to
  4448   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4449   and those of the form
  4450   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4451   are rewritten to
  4452   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4453 
  4454 * HOL/datatype
  4455   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4456 
  4457   P(t_case f1 ... fn x) =
  4458      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4459         ...
  4460        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4461      )
  4462 
  4463   and a theorem `split_t_case_asm' of the form
  4464 
  4465   P(t_case f1 ... fn x) =
  4466     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4467         ...
  4468        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4469      )
  4470   which can be added to a simpset via `addsplits'. The existing theorems
  4471   expand_list_case and expand_option_case have been renamed to
  4472   split_list_case and split_option_case.
  4473 
  4474 * HOL/Arithmetic:
  4475   - `pred n' is automatically converted to `n-1'.
  4476     Users are strongly encouraged not to use `pred' any longer,
  4477     because it will disappear altogether at some point.
  4478   - Users are strongly encouraged to write "0 < n" rather than
  4479     "n ~= 0". Theorems and proof tools have been modified towards this
  4480     `standard'.
  4481 
  4482 * HOL/Lists:
  4483   the function "set_of_list" has been renamed "set" (and its theorems too);
  4484   the function "nth" now takes its arguments in the reverse order and
  4485   has acquired the infix notation "!" as in "xs!n".
  4486 
  4487 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4488 
  4489 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4490   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4491 
  4492 * HOL/record: extensible records with schematic structural subtyping
  4493 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4494 still lacks various theorems and concrete record syntax;
  4495 
  4496 
  4497 *** HOLCF ***
  4498 
  4499 * removed "axioms" and "generated by" sections;
  4500 
  4501 * replaced "ops" section by extended "consts" section, which is capable of
  4502   handling the continuous function space "->" directly;
  4503 
  4504 * domain package:
  4505   . proves theorems immediately and stores them in the theory,
  4506   . creates hierachical name space,
  4507   . now uses normal mixfix annotations (instead of cinfix...),
  4508   . minor changes to some names and values (for consistency),
  4509   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4510   . separator between mutual domain defs: changed "," to "and",
  4511   . improved handling of sort constraints;  now they have to
  4512     appear on the left-hand side of the equations only;
  4513 
  4514 * fixed LAM <x,y,zs>.b syntax;
  4515 
  4516 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4517 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4518 
  4519 
  4520 *** FOL and ZF ***
  4521 
  4522 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4523   with `addloop' of the simplifier to faciliate case splitting in premises.
  4524 
  4525 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4526 in HOL, they strip ALL and --> from proved theorems;
  4527 
  4528 
  4529 
  4530 New in Isabelle94-8 (May 1997)
  4531 ------------------------------
  4532 
  4533 *** General Changes ***
  4534 
  4535 * new utilities to build / run / maintain Isabelle etc. (in parts
  4536 still somewhat experimental); old Makefiles etc. still functional;
  4537 
  4538 * new 'Isabelle System Manual';
  4539 
  4540 * INSTALL text, together with ./configure and ./build scripts;
  4541 
  4542 * reimplemented type inference for greater efficiency, better error
  4543 messages and clean internal interface;
  4544 
  4545 * prlim command for dealing with lots of subgoals (an easier way of
  4546 setting goals_limit);
  4547 
  4548 
  4549 *** Syntax ***
  4550 
  4551 * supports alternative (named) syntax tables (parser and pretty
  4552 printer); internal interface is provided by add_modesyntax(_i);
  4553 
  4554 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4555 be used in conjunction with the Isabelle symbol font; uses the
  4556 "symbols" syntax table;
  4557 
  4558 * added token_translation interface (may translate name tokens in
  4559 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4560 the current print_mode); IMPORTANT: user print translation functions
  4561 are responsible for marking newly introduced bounds
  4562 (Syntax.mark_boundT);
  4563 
  4564 * token translations for modes "xterm" and "xterm_color" that display
  4565 names in bold, underline etc. or colors (which requires a color
  4566 version of xterm);
  4567 
  4568 * infixes may now be declared with names independent of their syntax;
  4569 
  4570 * added typed_print_translation (like print_translation, but may
  4571 access type of constant);
  4572 
  4573 
  4574 *** Classical Reasoner ***
  4575 
  4576 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4577 some limitations.  Blast_tac...
  4578   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4579   + ignores elimination rules that don't have the correct format
  4580         (the conclusion MUST be a formula variable)
  4581   + ignores types, which can make HOL proofs fail
  4582   + rules must not require higher-order unification, e.g. apply_type in ZF
  4583     [message "Function Var's argument not a bound variable" relates to this]
  4584   + its proof strategy is more general but can actually be slower
  4585 
  4586 * substitution with equality assumptions no longer permutes other
  4587 assumptions;
  4588 
  4589 * minor changes in semantics of addafter (now called addaltern); renamed
  4590 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4591 (and access functions for it);
  4592 
  4593 * improved combination of classical reasoner and simplifier:
  4594   + functions for handling clasimpsets
  4595   + improvement of addss: now the simplifier is called _after_ the
  4596     safe steps.
  4597   + safe variant of addss called addSss: uses safe simplifications
  4598     _during_ the safe steps. It is more complete as it allows multiple
  4599     instantiations of unknowns (e.g. with slow_tac).
  4600 
  4601 *** Simplifier ***
  4602 
  4603 * added interface for simplification procedures (functions that
  4604 produce *proven* rewrite rules on the fly, depending on current
  4605 redex);
  4606 
  4607 * ordering on terms as parameter (used for ordered rewriting);
  4608 
  4609 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4610 
  4611 * the solver is now split into a safe and an unsafe part.
  4612 This should be invisible for the normal user, except that the
  4613 functions setsolver and addsolver have been renamed to setSolver and
  4614 addSolver; added safe_asm_full_simp_tac;
  4615 
  4616 
  4617 *** HOL ***
  4618 
  4619 * a generic induction tactic `induct_tac' which works for all datatypes and
  4620 also for type `nat';
  4621 
  4622 * a generic case distinction tactic `exhaust_tac' which works for all
  4623 datatypes and also for type `nat';
  4624 
  4625 * each datatype comes with a function `size';
  4626 
  4627 * patterns in case expressions allow tuple patterns as arguments to
  4628 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4629 
  4630 * primrec now also works with type nat;
  4631 
  4632 * recdef: a new declaration form, allows general recursive functions to be
  4633 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4634 
  4635 * the constant for negation has been renamed from "not" to "Not" to
  4636 harmonize with FOL, ZF, LK, etc.;
  4637 
  4638 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4639 infinite lists;
  4640 
  4641 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4642 
  4643 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4644 problems in commutative rings, using axiomatic type classes for + and *;
  4645 
  4646 * more examples in HOL/MiniML and HOL/Auth;
  4647 
  4648 * more default rewrite rules for quantifiers, union/intersection;
  4649 
  4650 * a new constant `arbitrary == @x.False';
  4651 
  4652 * HOLCF/IOA replaces old HOL/IOA;
  4653 
  4654 * HOLCF changes: derived all rules and arities
  4655   + axiomatic type classes instead of classes
  4656   + typedef instead of faking type definitions
  4657   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4658   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4659   + eliminated the types void, one, tr
  4660   + use unit lift and bool lift (with translations) instead of one and tr
  4661   + eliminated blift from Lift3.thy (use Def instead of blift)
  4662   all eliminated rules are derived as theorems --> no visible changes ;
  4663 
  4664 
  4665 *** ZF ***
  4666 
  4667 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4668 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4669 as ZF_cs addSIs [equalityI];
  4670 
  4671 
  4672 
  4673 New in Isabelle94-7 (November 96)
  4674 ---------------------------------
  4675 
  4676 * allowing negative levels (as offsets) in prlev and choplev;
  4677 
  4678 * super-linear speedup for large simplifications;
  4679 
  4680 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4681 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4682 FAIL); can suppress it using the command Delsimps (ex_simps @
  4683 all_simps); De Morgan laws are also now included, by default;
  4684 
  4685 * improved printing of ==>  :  ~:
  4686 
  4687 * new object-logic "Sequents" adds linear logic, while replacing LK
  4688 and Modal (thanks to Sara Kalvala);
  4689 
  4690 * HOL/Auth: correctness proofs for authentication protocols;
  4691 
  4692 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4693 examples on HOL/Auth);
  4694 
  4695 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4696 the rewriter and classical reasoner simultaneously;
  4697 
  4698 * function uresult no longer returns theorems in "standard" format;
  4699 regain previous version by: val uresult = standard o uresult;
  4700 
  4701 
  4702 
  4703 New in Isabelle94-6
  4704 -------------------
  4705 
  4706 * oracles -- these establish an interface between Isabelle and trusted
  4707 external reasoners, which may deliver results as theorems;
  4708 
  4709 * proof objects (in particular record all uses of oracles);
  4710 
  4711 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4712 
  4713 * "constdefs" section in theory files;
  4714 
  4715 * "primrec" section (HOL) no longer requires names;
  4716 
  4717 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4718 
  4719 
  4720 
  4721 New in Isabelle94-5
  4722 -------------------
  4723 
  4724 * reduced space requirements;
  4725 
  4726 * automatic HTML generation from theories;
  4727 
  4728 * theory files no longer require "..." (quotes) around most types;
  4729 
  4730 * new examples, including two proofs of the Church-Rosser theorem;
  4731 
  4732 * non-curried (1994) version of HOL is no longer distributed;
  4733 
  4734 
  4735 
  4736 New in Isabelle94-4
  4737 -------------------
  4738 
  4739 * greatly reduced space requirements;
  4740 
  4741 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4742 
  4743 * searchable theorem database (see the section "Retrieving theorems" on
  4744 page 8 of the Reference Manual);
  4745 
  4746 * new examples, including Grabczewski's monumental case study of the
  4747 Axiom of Choice;
  4748 
  4749 * The previous version of HOL renamed to Old_HOL;
  4750 
  4751 * The new version of HOL (previously called CHOL) uses a curried syntax
  4752 for functions.  Application looks like f a b instead of f(a,b);
  4753 
  4754 * Mutually recursive inductive definitions finally work in HOL;
  4755 
  4756 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4757 translates to the operator "split";
  4758 
  4759 
  4760 
  4761 New in Isabelle94-3
  4762 -------------------
  4763 
  4764 * new infix operator, addss, allowing the classical reasoner to
  4765 perform simplification at each step of its search.  Example:
  4766         fast_tac (cs addss ss)
  4767 
  4768 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4769 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4770 look like (a,b) instead of <a,b>;
  4771 
  4772 * PLEASE NOTE: CHOL will eventually replace HOL!
  4773 
  4774 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4775 It translates to the operator "split".  A new theory of integers is available;
  4776 
  4777 * In ZF, integer numerals now denote two's-complement binary integers.
  4778 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4779 
  4780 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4781 of the Axiom of Choice;
  4782 
  4783 
  4784 
  4785 New in Isabelle94-2
  4786 -------------------
  4787 
  4788 * Significantly faster resolution;
  4789 
  4790 * the different sections in a .thy file can now be mixed and repeated
  4791 freely;
  4792 
  4793 * Database of theorems for FOL, HOL and ZF.  New
  4794 commands including qed, qed_goal and bind_thm store theorems in the database.
  4795 
  4796 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4797 a given theory (thms_of), or find out what theory a theorem was proved in
  4798 (theory_of_thm);
  4799 
  4800 * Bugs fixed in the inductive definition and datatype packages;
  4801 
  4802 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4803 and HOL_dup_cs obsolete;
  4804 
  4805 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4806 have been removed;
  4807 
  4808 * Simpler definition of function space in ZF;
  4809 
  4810 * new results about cardinal and ordinal arithmetic in ZF;
  4811 
  4812 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4813 types;
  4814 
  4815 
  4816 $Id$