NEWS
author nipkow
Sun Jun 24 20:47:05 2007 +0200 (2007-06-24)
changeset 23481 93dca7620d0d
parent 23480 8d01ccdc3652
child 23495 e4dd6beeafab
permissions -rw-r--r--
*** empty log message ***
     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 * New lemma collection field_simps (an extension of ring_simps)
   607   for manipulating (in)equations involving division. Multiplies
   608   with all denominators that can be proved to be non-zero (in equations)
   609   or positive/negative (in inequations).
   610 
   611 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
   612   have been improved and renamed to ring_simps, group_simps and ring_distribs.
   613 
   614 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   615   when generating code.
   616 
   617 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   618   when generating code.
   619 
   620 * Library/Commutative_Ring.thy: switched from recdef to function package;
   621   constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   622 
   623 * Some steps towards more uniform lattice theory development in HOL.
   624 
   625     constants "meet" and "join" now named "inf" and "sup"
   626     constant "Meet" now named "Inf"
   627 
   628     classes "meet_semilorder" and "join_semilorder" now named
   629       "lower_semilattice" and "upper_semilattice"
   630     class "lorder" now named "lattice"
   631     class "comp_lat" now named "complete_lattice"
   632 
   633     Instantiation of lattice classes allows explicit definitions
   634     for "inf" and "sup" operations.
   635 
   636   INCOMPATIBILITY.  Theorem renames:
   637 
   638     meet_left_le            ~> inf_le1
   639     meet_right_le           ~> inf_le2
   640     join_left_le            ~> sup_ge1
   641     join_right_le           ~> sup_ge2
   642     meet_join_le            ~> inf_sup_ord
   643     le_meetI                ~> le_infI
   644     join_leI                ~> le_supI
   645     le_meet                 ~> le_inf_iff
   646     le_join                 ~> ge_sup_conv
   647     meet_idempotent         ~> inf_idem
   648     join_idempotent         ~> sup_idem
   649     meet_comm               ~> inf_commute
   650     join_comm               ~> sup_commute
   651     meet_leI1               ~> le_infI1
   652     meet_leI2               ~> le_infI2
   653     le_joinI1               ~> le_supI1
   654     le_joinI2               ~> le_supI2
   655     meet_assoc              ~> inf_assoc
   656     join_assoc              ~> sup_assoc
   657     meet_left_comm          ~> inf_left_commute
   658     meet_left_idempotent    ~> inf_left_idem
   659     join_left_comm          ~> sup_left_commute
   660     join_left_idempotent    ~> sup_left_idem
   661     meet_aci                ~> inf_aci
   662     join_aci                ~> sup_aci
   663     le_def_meet             ~> le_iff_inf
   664     le_def_join             ~> le_iff_sup
   665     join_absorp2            ~> sup_absorb2
   666     join_absorp1            ~> sup_absorb1
   667     meet_absorp1            ~> inf_absorb1
   668     meet_absorp2            ~> inf_absorb2
   669     meet_join_absorp        ~> inf_sup_absorb
   670     join_meet_absorp        ~> sup_inf_absorb
   671     distrib_join_le         ~> distrib_sup_le
   672     distrib_meet_le         ~> distrib_inf_le
   673 
   674     add_meet_distrib_left   ~> add_inf_distrib_left
   675     add_join_distrib_left   ~> add_sup_distrib_left
   676     is_join_neg_meet        ~> is_join_neg_inf
   677     is_meet_neg_join        ~> is_meet_neg_sup
   678     add_meet_distrib_right  ~> add_inf_distrib_right
   679     add_join_distrib_right  ~> add_sup_distrib_right
   680     add_meet_join_distribs  ~> add_sup_inf_distribs
   681     join_eq_neg_meet        ~> sup_eq_neg_inf
   682     meet_eq_neg_join        ~> inf_eq_neg_sup
   683     add_eq_meet_join        ~> add_eq_inf_sup
   684     meet_0_imp_0            ~> inf_0_imp_0
   685     join_0_imp_0            ~> sup_0_imp_0
   686     meet_0_eq_0             ~> inf_0_eq_0
   687     join_0_eq_0             ~> sup_0_eq_0
   688     neg_meet_eq_join        ~> neg_inf_eq_sup
   689     neg_join_eq_meet        ~> neg_sup_eq_inf
   690     join_eq_if              ~> sup_eq_if
   691 
   692     mono_meet               ~> mono_inf
   693     mono_join               ~> mono_sup
   694     meet_bool_eq            ~> inf_bool_eq
   695     join_bool_eq            ~> sup_bool_eq
   696     meet_fun_eq             ~> inf_fun_eq
   697     join_fun_eq             ~> sup_fun_eq
   698     meet_set_eq             ~> inf_set_eq
   699     join_set_eq             ~> sup_set_eq
   700     meet1_iff               ~> inf1_iff
   701     meet2_iff               ~> inf2_iff
   702     meet1I                  ~> inf1I
   703     meet2I                  ~> inf2I
   704     meet1D1                 ~> inf1D1
   705     meet2D1                 ~> inf2D1
   706     meet1D2                 ~> inf1D2
   707     meet2D2                 ~> inf2D2
   708     meet1E                  ~> inf1E
   709     meet2E                  ~> inf2E
   710     join1_iff               ~> sup1_iff
   711     join2_iff               ~> sup2_iff
   712     join1I1                 ~> sup1I1
   713     join2I1                 ~> sup2I1
   714     join1I1                 ~> sup1I1
   715     join2I2                 ~> sup1I2
   716     join1CI                 ~> sup1CI
   717     join2CI                 ~> sup2CI
   718     join1E                  ~> sup1E
   719     join2E                  ~> sup2E
   720 
   721     is_meet_Meet            ~> is_meet_Inf
   722     Meet_bool_def           ~> Inf_bool_def
   723     Meet_fun_def            ~> Inf_fun_def
   724     Meet_greatest           ~> Inf_greatest
   725     Meet_lower              ~> Inf_lower
   726     Meet_set_def            ~> Inf_set_def
   727 
   728     listsp_meetI            ~> listsp_infI
   729     listsp_meet_eq          ~> listsp_inf_eq
   730 
   731     meet_min                ~> inf_min
   732     join_max                ~> sup_max
   733 
   734 * Classes "order" and "linorder": facts "refl", "trans" and
   735 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   736 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   737 
   738 * Classes "order" and "linorder": 
   739 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   740 proofs changed.
   741 
   742 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   743 INCOMPATIBILITY.
   744 
   745 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   746 INCOMPATIBILITY.
   747 
   748 * Added syntactic class "size"; overloaded constant "size" now has
   749 type "'a::size ==> bool"
   750 
   751 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   752 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   753 
   754 * Added method "lexicographic_order" automatically synthesizes
   755 termination relations as lexicographic combinations of size measures
   756 -- 'function' package.
   757 
   758 * HOL/records: generalised field-update to take a function on the
   759 field rather than the new value: r(|A := x|) is translated to A_update
   760 (K x) r The K-combinator that is internally used is called K_record.
   761 INCOMPATIBILITY: Usage of the plain update functions has to be
   762 adapted.
   763  
   764 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   765 0 * x = 0, which are required for a semiring.  Richer structures do
   766 not inherit from semiring_0 anymore, because this property is a
   767 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   768 semiring_0, there is more to prove, but this is mostly trivial.
   769 
   770 * axclass "recpower" was generalized to arbitrary monoids, not just
   771 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   772 commutativity or a semiring property, add the corresponding classes.
   773 
   774 * Unified locale partial_order with class definition (cf. theory
   775 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   776 
   777 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   778 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   779 Isar level, use abbreviations instead.
   780 
   781 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   782 rarely occuring name references (e.g. ``List.op mem.simps'') require
   783 renaming (e.g. ``List.memberl.simps'').
   784 
   785 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   786 INCOMPATIBILITY.
   787 
   788 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   789 
   790 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   791 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   792 significant changes for setting up numeral syntax for types:
   793 
   794   - new constants Numeral.pred and Numeral.succ instead
   795       of former Numeral.bin_pred and Numeral.bin_succ.
   796   - Use integer operations instead of bin_add, bin_mult and so on.
   797   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   798   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   799 
   800 See HOL/Integ/IntArith.thy for an example setup.
   801 
   802 * New top level command 'normal_form' computes the normal form of a
   803 term that may contain free variables. For example ``normal_form
   804 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   805 suitable for heavy-duty computations because the functions are
   806 compiled to ML first.
   807 
   808 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   809 25 like -->); output depends on the "iff" print_mode, the default is
   810 "A = B" (with priority 50).
   811 
   812 * Renamed constants in HOL.thy and Orderings.thy:
   813     op +   ~> HOL.plus_class.plus
   814     op -   ~> HOL.minus_class.minus
   815     uminus ~> HOL.minus_class.uminus
   816     op *   ~> HOL.times_class.times
   817     op <   ~> Orderings.ord_class.less
   818     op <=  ~> Orderings.ord_class.less_eq
   819 
   820 Adaptions may be required in the following cases:
   821 
   822 a) User-defined constants using any of the names "plus", "minus", "times",
   823 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   824 may go wrong.
   825 INCOMPATIBILITY: use more specific names.
   826 
   827 b) Variables named "plus", "minus", "times", "less", "less_eq"
   828 INCOMPATIBILITY: use more specific names.
   829 
   830 c) Permutative equations (e.g. "a + b = b + a")
   831 Since the change of names also changes the order of terms, permutative
   832 rewrite rules may get applied in a different order. Experience shows that
   833 this is rarely the case (only two adaptions in the whole Isabelle
   834 distribution).
   835 INCOMPATIBILITY: rewrite proofs
   836 
   837 d) ML code directly refering to constant names
   838 This in general only affects hand-written proof tactics, simprocs and so on.
   839 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   840 of const_name ML antiquotations.
   841 
   842 * Relations less (<) and less_eq (<=) are also available on type bool.
   843 Modified syntax to disallow nesting without explicit parentheses,
   844 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   845 
   846 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   847 
   848 * Relation composition operator "op O" now has precedence 75 and binds
   849 stronger than union and intersection. INCOMPATIBILITY.
   850 
   851 * The old set interval syntax "{m..n(}" (and relatives) has been
   852 removed.  Use "{m..<n}" (and relatives) instead.
   853 
   854 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   855 "t = s" to False (by simproc "neq_simproc").  For backward
   856 compatibility this can be disabled by ML "reset use_neq_simproc".
   857 
   858 * "m dvd n" where m and n are numbers is evaluated to True/False by
   859 simp.
   860 
   861 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   862 
   863 * Theorem setsum_mult renamed to setsum_right_distrib.
   864 
   865 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   866 ``rule'' method.
   867 
   868 * Reimplemented methods ``sat'' and ``satx'', with several
   869 improvements: goals no longer need to be stated as "<prems> ==>
   870 False", equivalences (i.e. "=" on type bool) are handled, variable
   871 names of the form "lit_<n>" are no longer reserved, significant
   872 speedup.
   873 
   874 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   875 zChaff is still supported as well.
   876 
   877 * 'inductive' and 'datatype': provide projections of mutual rules,
   878 bundled as foo_bar.inducts;
   879 
   880 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   881 Library.
   882 
   883 * Library: moved theory Accessible_Part to main HOL.
   884 
   885 * Library: added theory Coinductive_List of potentially infinite lists
   886 as greatest fixed-point.
   887 
   888 * Library: added theory AssocList which implements (finite) maps as
   889 association lists.
   890 
   891 * Added proof method ``evaluation'' for efficiently solving a goal
   892 (i.e. a boolean expression) by compiling it to ML. The goal is
   893 "proved" (via an oracle) if it evaluates to True.
   894 
   895 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   896 also when invoked by the simplifier.  This results in the simplifier
   897 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   898 fast_arith_split_limit to 0 to obtain the old behavior.
   899 
   900 * Support for hex (0x20) and binary (0b1001) numerals.
   901 
   902 * New method: reify eqs (t), where eqs are equations for an
   903 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   904 parameter, computes a term s::'b and a list xs::'a list and proves the
   905 theorem I xs s = t. This is also known as reification or quoting. The
   906 resulting theorem is applied to the subgoal to substitute t with I xs
   907 s.  If t is omitted, the subgoal itself is reified.
   908 
   909 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   910 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   911 where f is supposed to be a computable function (in the sense of code
   912 generattion). The method uses reify to compute s and xs as above then
   913 applies corr_thm and uses normalization by evaluation to "prove" f s =
   914 r and finally gets the theorem t = r, which is again applied to the
   915 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   916 
   917 * Reflection: Automatic refification now handels binding, an example
   918 is available in HOL/ex/ReflectionEx.thy
   919 
   920 
   921 *** HOL-Algebra ***
   922 
   923 * Formalisation of ideals and the quotient construction over rings.
   924 
   925 * Order and lattice theory no longer based on records.
   926 INCOMPATIBILITY.
   927 
   928 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   929 greatest_closed.  INCOMPATIBILITY.
   930 
   931 * Method algebra is now set up via an attribute.  For examples see
   932 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   933 of algebraic structures.
   934 
   935 * Renamed theory CRing to Ring.
   936 
   937 
   938 *** HOL-Complex ***
   939 
   940 * Theory Real: new method ferrack implements quantifier elimination
   941 for linear arithmetic over the reals. The quantifier elimination
   942 feature is used only for decision, for compatibility with arith. This
   943 means a goal is either solved or left unchanged, no simplification.
   944 
   945 * Hyperreal: Functions root and sqrt are now defined on negative real
   946 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   947 Nonnegativity side conditions have been removed from many lemmas, so
   948 that more subgoals may now be solved by simplification; potential
   949 INCOMPATIBILITY.
   950 
   951 * Real: New axiomatic classes formalize real normed vector spaces and
   952 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   953 and norm :: 'a => real.
   954 
   955 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   956 from reals into other types. The overloaded constant Reals :: 'a set
   957 is now defined as range of_real; potential INCOMPATIBILITY.
   958 
   959 * Real: ML code generation is supported now and hence also quickcheck.
   960 Reals are implemented as arbitrary precision rationals.
   961 
   962 * Hyperreal: Several constants that previously worked only for the
   963 reals have been generalized, so they now work over arbitrary vector
   964 spaces. Type annotations may need to be added in some cases; potential
   965 INCOMPATIBILITY.
   966 
   967   Infinitesimal  :: ('a::real_normed_vector) star set
   968   HFinite        :: ('a::real_normed_vector) star set
   969   HInfinite      :: ('a::real_normed_vector) star set
   970   approx         :: ('a::real_normed_vector) star => 'a star => bool
   971   monad          :: ('a::real_normed_vector) star => 'a star set
   972   galaxy         :: ('a::real_normed_vector) star => 'a star set
   973   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   974   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   975   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   976   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   977   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   978   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   979   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   980   sgn            :: 'a::real_normed_vector => 'a
   981   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   982 
   983 * Complex: Some complex-specific constants are now abbreviations for
   984 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   985 hnorm.  Other constants have been entirely removed in favor of the
   986 polymorphic versions (INCOMPATIBILITY):
   987 
   988   approx        <-- capprox
   989   HFinite       <-- CFinite
   990   HInfinite     <-- CInfinite
   991   Infinitesimal <-- CInfinitesimal
   992   monad         <-- cmonad
   993   galaxy        <-- cgalaxy
   994   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   995   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   996   (ns)deriv     <-- (ns)cderiv
   997 
   998 
   999 *** ML ***
  1000 
  1001 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
  1002 
  1003 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1004 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1005 init only required for impure data.  INCOMPATIBILITY: empty really
  1006 need to be empty (no dependencies on theory content!)
  1007 
  1008 * ML within Isar: antiquotations allow to embed statically-checked
  1009 formal entities in the source, referring to the context available at
  1010 compile-time.  For example:
  1011 
  1012 ML {* @{typ "'a => 'b"} *}
  1013 ML {* @{term "%x. x"} *}
  1014 ML {* @{prop "x == y"} *}
  1015 ML {* @{ctyp "'a => 'b"} *}
  1016 ML {* @{cterm "%x. x"} *}
  1017 ML {* @{cprop "x == y"} *}
  1018 ML {* @{thm asm_rl} *}
  1019 ML {* @{thms asm_rl} *}
  1020 ML {* @{const_name c} *}
  1021 ML {* @{const_syntax c} *}
  1022 ML {* @{context} *}
  1023 ML {* @{theory} *}
  1024 ML {* @{theory Pure} *}
  1025 ML {* @{simpset} *}
  1026 ML {* @{claset} *}
  1027 ML {* @{clasimpset} *}
  1028 
  1029 The same works for sources being ``used'' within an Isar context.
  1030 
  1031 * ML in Isar: improved error reporting; extra verbosity with
  1032 Toplevel.debug enabled.
  1033 
  1034 * Pure/library:
  1035 
  1036   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1037   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1038 
  1039 The semantics of "burrow" is: "take a function with *simulatanously*
  1040 transforms a list of value, and apply it *simulatanously* to a list of
  1041 list of values of the appropriate type". Compare this with "map" which
  1042 would *not* apply its argument function simulatanously but in
  1043 sequence; "fold_burrow" has an additional context.
  1044 
  1045 * Pure/library: functions map2 and fold2 with curried syntax for
  1046 simultanous mapping and folding:
  1047 
  1048     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1049     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1050 
  1051 * Pure/library: indexed lists - some functions in the Isabelle library
  1052 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1053 given more convenient names and signatures reminiscent of similar
  1054 functions for alists, tables, etc:
  1055 
  1056   val nth: 'a list -> int -> 'a 
  1057   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1058   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1059 
  1060 Note that fold_index starts counting at index 0, not 1 like foldln
  1061 used to.
  1062 
  1063 * Pure/library: added general ``divide_and_conquer'' combinator on
  1064 lists.
  1065 
  1066 * Pure/General/table.ML: the join operations now works via exceptions
  1067 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1068 admits slightly more efficient complex applications.
  1069 
  1070 * Pure: datatype Context.generic joins theory/Proof.context and
  1071 provides some facilities for code that works in either kind of
  1072 context, notably GenericDataFun for uniform theory and proof data.
  1073 
  1074 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1075 use Context.generic instead of just theory.
  1076 
  1077 * Pure: simplified internal attribute type, which is now always
  1078 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1079 vs. local (Proof.context) attributes have been discontinued, while
  1080 minimizing code duplication.  Thm.rule_attribute and
  1081 Thm.declaration_attribute build canonical attributes; see also
  1082 structure Context for further operations on Context.generic, notably
  1083 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1084 declarations and definitions.
  1085 
  1086 * Pure/kernel: consts certification ignores sort constraints given in
  1087 signature declarations.  (This information is not relevant to the
  1088 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1089 potential INCOMPATIBILITY.
  1090 
  1091 * Pure: axiomatic type classes are now purely definitional, with
  1092 explicit proofs of class axioms and super class relations performed
  1093 internally.  See Pure/axclass.ML for the main internal interfaces --
  1094 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1095 AxClass.axiomatize_class/classrel/arity supercede
  1096 Sign.add_classes/classrel/arities.
  1097 
  1098 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1099 global/local versions on theory vs. Proof.context have been
  1100 discontinued; Attrib.syntax and Method.syntax have been adapted
  1101 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1102 attributes, methods, etc.
  1103 
  1104 * Pure: several functions of signature "... -> theory -> theory * ..."
  1105 have been reoriented to "... -> theory -> ... * theory" in order to
  1106 allow natural usage in combination with the ||>, ||>>, |-> and
  1107 fold_map combinators.
  1108 
  1109 * Pure: official theorem names (closed derivations) and additional
  1110 comments (tags) are now strictly separate.  Name hints -- which are
  1111 maintained as tags -- may be attached any time without affecting the
  1112 derivation.
  1113 
  1114 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1115 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1116 achieve the old behaviour.
  1117 
  1118 * Pure: the "Goal" constant is now called "prop", supporting a
  1119 slightly more general idea of ``protecting'' meta-level rule
  1120 statements.
  1121 
  1122 * Pure: Logic.(un)varify only works in a global context, which is now
  1123 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1124 Logic.legacy_(un)varify as temporary workaround.
  1125 
  1126 * Pure: structure Name provides scalable operations for generating
  1127 internal variable names, notably Name.variants etc.  This replaces
  1128 some popular functions from term.ML:
  1129 
  1130   Term.variant		->  Name.variant
  1131   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1132   Term.invent_names	->  Name.invent_list
  1133 
  1134 Note that low-level renaming rarely occurs in new code -- operations
  1135 from structure Variable are used instead (see below).
  1136 
  1137 * Pure: structure Variable provides fundamental operations for proper
  1138 treatment of fixed/schematic variables in a context.  For example,
  1139 Variable.import introduces fixes for schematics of given facts and
  1140 Variable.export reverses the effect (up to renaming) -- this replaces
  1141 various freeze_thaw operations.
  1142 
  1143 * Pure: structure Goal provides simple interfaces for
  1144 init/conclude/finish and tactical prove operations (replacing former
  1145 Tactic.prove).  Goal.prove is the canonical way to prove results
  1146 within a given context; Goal.prove_global is a degraded version for
  1147 theory level goals, including a global Drule.standard.  Note that
  1148 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1149 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1150 in a locale context).
  1151 
  1152 * Isar: simplified treatment of user-level errors, using exception
  1153 ERROR of string uniformly.  Function error now merely raises ERROR,
  1154 without any side effect on output channels.  The Isar toplevel takes
  1155 care of proper display of ERROR exceptions.  ML code may use plain
  1156 handle/can/try; cat_error may be used to concatenate errors like this:
  1157 
  1158   ... handle ERROR msg => cat_error msg "..."
  1159 
  1160 Toplevel ML code (run directly or through the Isar toplevel) may be
  1161 embedded into the Isar toplevel with exception display/debug like
  1162 this:
  1163 
  1164   Isar.toplevel (fn () => ...)
  1165 
  1166 INCOMPATIBILITY, removed special transform_error facilities, removed
  1167 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1168 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1169 -- use plain ERROR instead.
  1170 
  1171 * Isar: theory setup now has type (theory -> theory), instead of a
  1172 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1173 
  1174 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1175 subject to ProofContext.debug/verbose flags.
  1176 
  1177 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1178 theory before entering a proof state.  Transactions now always see a
  1179 quasi-functional intermediate checkpoint, both in interactive and
  1180 batch mode.
  1181 
  1182 * Simplifier: the simpset of a running simplification process now
  1183 contains a proof context (cf. Simplifier.the_context), which is the
  1184 very context that the initial simpset has been retrieved from (by
  1185 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1186 (solver, looper etc.) may depend on arbitrary proof data.
  1187 
  1188 * Simplifier.inherit_context inherits the proof context (plus the
  1189 local bounds) of the current simplification process; any simproc
  1190 etc. that calls the Simplifier recursively should do this!  Removed
  1191 former Simplifier.inherit_bounds, which is already included here --
  1192 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1193 specify an explicit context using Simplifier.context/theory_context.
  1194 
  1195 * Simplifier/Classical Reasoner: more abstract interfaces
  1196 change_simpset/claset for modifying the simpset/claset reference of a
  1197 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1198 INCOMPATIBILITY.
  1199 
  1200 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1201 "Trueprop" etc.
  1202 
  1203 
  1204 *** System ***
  1205 
  1206 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1207 locations -- now includes the Isabelle version identifier as well.
  1208 This simplifies use of multiple Isabelle installations.
  1209 
  1210 * isabelle-process: option -S (secure mode) disables some critical
  1211 operations, notably runtime compilation and evaluation of ML source
  1212 code.
  1213 
  1214 
  1215 New in Isabelle2005 (October 2005)
  1216 ----------------------------------
  1217 
  1218 *** General ***
  1219 
  1220 * Theory headers: the new header syntax for Isar theories is
  1221 
  1222   theory <name>
  1223   imports <theory1> ... <theoryN>
  1224   uses <file1> ... <fileM>
  1225   begin
  1226 
  1227 where the 'uses' part is optional.  The previous syntax
  1228 
  1229   theory <name> = <theory1> + ... + <theoryN>:
  1230 
  1231 will disappear in the next release.  Use isatool fixheaders to convert
  1232 existing theory files.  Note that there is no change in ancient
  1233 non-Isar theories now, but these will disappear soon.
  1234 
  1235 * Theory loader: parent theories can now also be referred to via
  1236 relative and absolute paths.
  1237 
  1238 * Command 'find_theorems' searches for a list of criteria instead of a
  1239 list of constants. Known criteria are: intro, elim, dest, name:string,
  1240 simp:term, and any term. Criteria can be preceded by '-' to select
  1241 theorems that do not match. Intro, elim, dest select theorems that
  1242 match the current goal, name:s selects theorems whose fully qualified
  1243 name contain s, and simp:term selects all simplification rules whose
  1244 lhs match term.  Any other term is interpreted as pattern and selects
  1245 all theorems matching the pattern. Available in ProofGeneral under
  1246 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1247 
  1248   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1249 
  1250 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1251 matching the current goal as introduction rule and not having "HOL."
  1252 in their name (i.e. not being defined in theory HOL).
  1253 
  1254 * Command 'thms_containing' has been discontinued in favour of
  1255 'find_theorems'; INCOMPATIBILITY.
  1256 
  1257 * Communication with Proof General is now 8bit clean, which means that
  1258 Unicode text in UTF-8 encoding may be used within theory texts (both
  1259 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1260 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1261 
  1262   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1263   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1264 
  1265 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1266 Classical Reasoner.  Typical big applications run around 2 times
  1267 faster.
  1268 
  1269 
  1270 *** Document preparation ***
  1271 
  1272 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1273 of raw sources.  Only those symbols that do not require additional
  1274 LaTeX packages (depending on comments in isabellesym.sty) are
  1275 displayed properly, everything else is left verbatim.  isatool display
  1276 and isatool print are used as front ends (these are subject to the
  1277 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1278 
  1279 * Command tags control specific markup of certain regions of text,
  1280 notably folding and hiding.  Predefined tags include "theory" (for
  1281 theory begin and end), "proof" for proof commands, and "ML" for
  1282 commands involving ML code; the additional tags "visible" and
  1283 "invisible" are unused by default.  Users may give explicit tag
  1284 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1285 interpretation of tags is determined by the LaTeX job during document
  1286 preparation: see option -V of isatool usedir, or options -n and -t of
  1287 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1288 \isadroptag.
  1289 
  1290 Several document versions may be produced at the same time via isatool
  1291 usedir (the generated index.html will link all of them).  Typical
  1292 specifications include ''-V document=theory,proof,ML'' to present
  1293 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1294 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1295 these parts without any formal replacement text.  The Isabelle site
  1296 default settings produce ''document'' and ''outline'' versions as
  1297 specified above.
  1298 
  1299 * Several new antiquotations:
  1300 
  1301   @{term_type term} prints a term with its type annotated;
  1302 
  1303   @{typeof term} prints the type of a term;
  1304 
  1305   @{const const} is the same as @{term const}, but checks that the
  1306   argument is a known logical constant;
  1307 
  1308   @{term_style style term} and @{thm_style style thm} print a term or
  1309   theorem applying a "style" to it
  1310 
  1311   @{ML text}
  1312 
  1313 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1314 definitions, equations, inequations etc., 'concl' printing only the
  1315 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1316 to print the specified premise.  TermStyle.add_style provides an ML
  1317 interface for introducing further styles.  See also the "LaTeX Sugar"
  1318 document practical applications.  The ML antiquotation prints
  1319 type-checked ML expressions verbatim.
  1320 
  1321 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1322 and 'text' support optional locale specification '(in loc)', which
  1323 specifies the default context for interpreting antiquotations.  For
  1324 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1325 
  1326 * Option 'locale=NAME' of antiquotations specifies an alternative
  1327 context interpreting the subsequent argument.  For example: @{thm
  1328 [locale=lattice] inf_assoc}.
  1329 
  1330 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1331 a proof context.
  1332 
  1333 * Proper output of antiquotations for theory commands involving a
  1334 proof context (such as 'locale' or 'theorem (in loc) ...').
  1335 
  1336 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1337 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1338 
  1339 * isatool usedir: new option -C (default true) controls whether option
  1340 -D should include a copy of the original document directory; -C false
  1341 prevents unwanted effects such as copying of administrative CVS data.
  1342 
  1343 
  1344 *** Pure ***
  1345 
  1346 * Considerably improved version of 'constdefs' command.  Now performs
  1347 automatic type-inference of declared constants; additional support for
  1348 local structure declarations (cf. locales and HOL records), see also
  1349 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1350 sequential dependencies of definitions within a single 'constdefs'
  1351 section; moreover, the declared name needs to be an identifier.  If
  1352 all fails, consider to fall back on 'consts' and 'defs' separately.
  1353 
  1354 * Improved indexed syntax and implicit structures.  First of all,
  1355 indexed syntax provides a notational device for subscripted
  1356 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1357 expressions.  Secondly, in a local context with structure
  1358 declarations, number indexes \<^sub>n or the empty index (default
  1359 number 1) refer to a certain fixed variable implicitly; option
  1360 show_structs controls printing of implicit structures.  Typical
  1361 applications of these concepts involve record types and locales.
  1362 
  1363 * New command 'no_syntax' removes grammar declarations (and
  1364 translations) resulting from the given syntax specification, which is
  1365 interpreted in the same manner as for the 'syntax' command.
  1366 
  1367 * 'Advanced' translation functions (parse_translation etc.) may depend
  1368 on the signature of the theory context being presently used for
  1369 parsing/printing, see also isar-ref manual.
  1370 
  1371 * Improved 'oracle' command provides a type-safe interface to turn an
  1372 ML expression of type theory -> T -> term into a primitive rule of
  1373 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1374 is already included here); see also FOL/ex/IffExample.thy;
  1375 INCOMPATIBILITY.
  1376 
  1377 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1378 before); "cI" is no longer bound, use "c.intro" instead.
  1379 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1380 axclasses vs. locales.
  1381 
  1382 * Improved internal renaming of symbolic identifiers -- attach primes
  1383 instead of base 26 numbers.
  1384 
  1385 * New flag show_question_marks controls printing of leading question
  1386 marks in schematic variable names.
  1387 
  1388 * In schematic variable names, *any* symbol following \<^isub> or
  1389 \<^isup> is now treated as part of the base name.  For example, the
  1390 following works without printing of awkward ".0" indexes:
  1391 
  1392   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1393     by simp
  1394 
  1395 * Inner syntax includes (*(*nested*) comments*).
  1396 
  1397 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1398 annotations as "(00...)".
  1399 
  1400 * Clear separation of logical types and nonterminals, where the latter
  1401 may only occur in 'syntax' specifications or type abbreviations.
  1402 Before that distinction was only partially implemented via type class
  1403 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1404 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1405 exotic syntax specifications may require further adaption
  1406 (e.g. Cube/Cube.thy).
  1407 
  1408 * Removed obsolete type class "logic", use the top sort {} instead.
  1409 Note that non-logical types should be declared as 'nonterminals'
  1410 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1411 specifications.
  1412 
  1413 * Attributes 'induct' and 'cases': type or set names may now be
  1414 locally fixed variables as well.
  1415 
  1416 * Simplifier: can now control the depth to which conditional rewriting
  1417 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1418 Limit.
  1419 
  1420 * Simplifier: simplification procedures may now take the current
  1421 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1422 interface), which is very useful for calling the Simplifier
  1423 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1424 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1425 low-level mk_simproc no longer applies Logic.varify internally, to
  1426 allow for use in a context of fixed variables.
  1427 
  1428 * thin_tac now works even if the assumption being deleted contains !!
  1429 or ==>.  More generally, erule now works even if the major premise of
  1430 the elimination rule contains !! or ==>.
  1431 
  1432 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1433 
  1434 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1435 from Pure, which contains all common declarations already.  Both
  1436 theories are defined via plain Isabelle/Isar .thy files.
  1437 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1438 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1439 use isatool fixcpure to adapt your theory and ML sources.
  1440 
  1441 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1442 selections of theorems in named facts via index ranges.
  1443 
  1444 * 'print_theorems': in theory mode, really print the difference
  1445 wrt. the last state (works for interactive theory development only),
  1446 in proof mode print all local facts (cf. 'print_facts');
  1447 
  1448 * 'hide': option '(open)' hides only base names.
  1449 
  1450 * More efficient treatment of intermediate checkpoints in interactive
  1451 theory development.
  1452 
  1453 * Code generator is now invoked via code_module (incremental code
  1454 generation) and code_library (modular code generation, ML structures
  1455 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1456 must be quoted when used as identifiers.
  1457 
  1458 * New 'value' command for reading, evaluating and printing terms using
  1459 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1460 quoted when used as identifier.
  1461 
  1462 
  1463 *** Locales ***
  1464 
  1465 * New commands for the interpretation of locale expressions in
  1466 theories (1), locales (2) and proof contexts (3).  These generate
  1467 proof obligations from the expression specification.  After the
  1468 obligations have been discharged, theorems of the expression are added
  1469 to the theory, target locale or proof context.  The synopsis of the
  1470 commands is a follows:
  1471 
  1472   (1) interpretation expr inst
  1473   (2) interpretation target < expr
  1474   (3) interpret expr inst
  1475 
  1476 Interpretation in theories and proof contexts require a parameter
  1477 instantiation of terms from the current context.  This is applied to
  1478 specifications and theorems of the interpreted expression.
  1479 Interpretation in locales only permits parameter renaming through the
  1480 locale expression.  Interpretation is smart in that interpretations
  1481 that are active already do not occur in proof obligations, neither are
  1482 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1483 inspect active interpretations of a particular locale.  For details,
  1484 see the Isar Reference manual.  Examples can be found in
  1485 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1486 
  1487 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1488 'interpret' instead.
  1489 
  1490 * New context element 'constrains' for adding type constraints to
  1491 parameters.
  1492 
  1493 * Context expressions: renaming of parameters with syntax
  1494 redeclaration.
  1495 
  1496 * Locale declaration: 'includes' disallowed.
  1497 
  1498 * Proper static binding of attribute syntax -- i.e. types / terms /
  1499 facts mentioned as arguments are always those of the locale definition
  1500 context, independently of the context of later invocations.  Moreover,
  1501 locale operations (renaming and type / term instantiation) are applied
  1502 to attribute arguments as expected.
  1503 
  1504 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1505 actual attributes; rare situations may require Attrib.attribute to
  1506 embed those attributes into Attrib.src that lack concrete syntax.
  1507 Attribute implementations need to cooperate properly with the static
  1508 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1509 Attrib.XXX_thm etc. already do the right thing without further
  1510 intervention.  Only unusual applications -- such as "where" or "of"
  1511 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1512 on the context and the facts involved -- may have to assign parsed
  1513 values to argument tokens explicitly.
  1514 
  1515 * Changed parameter management in theorem generation for long goal
  1516 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1517 theorem statement in rare situations.
  1518 
  1519 * Locale inspection command 'print_locale' omits notes elements.  Use
  1520 'print_locale!' to have them included in the output.
  1521 
  1522 
  1523 *** Provers ***
  1524 
  1525 * Provers/hypsubst.ML: improved version of the subst method, for
  1526 single-step rewriting: it now works in bound variable contexts. New is
  1527 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1528 rewrite a different subterm than the original subst method, which is
  1529 still available as 'simplesubst'.
  1530 
  1531 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1532 and quasi orders.
  1533 
  1534 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1535 reflexive-transitive closure of relations.
  1536 
  1537 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1538 limit (previously hard-coded with a value of 20) user-definable.
  1539 
  1540 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1541 is peformed already.  Object-logics merely need to finish their
  1542 initial simpset configuration as before.  INCOMPATIBILITY.
  1543 
  1544 
  1545 *** HOL ***
  1546 
  1547 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1548 
  1549   syntax (epsilon)
  1550     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1551 
  1552 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1553 and x-symbol; use option '-m epsilon' to get it actually printed.
  1554 Moreover, the mathematically important symbolic identifier \<epsilon>
  1555 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1556 
  1557 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1558 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1559 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1560 support corresponding Isar calculations.
  1561 
  1562 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1563 instead of ":".
  1564 
  1565 * theory SetInterval: changed the syntax for open intervals:
  1566 
  1567   Old       New
  1568   {..n(}    {..<n}
  1569   {)n..}    {n<..}
  1570   {m..n(}   {m..<n}
  1571   {)m..n}   {m<..n}
  1572   {)m..n(}  {m<..<n}
  1573 
  1574 The old syntax is still supported but will disappear in the next
  1575 release.  For conversion use the following Emacs search and replace
  1576 patterns (these are not perfect but work quite well):
  1577 
  1578   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1579   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1580 
  1581 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1582 equalities in commutative rings; method 'algebra' provides a generic
  1583 interface.
  1584 
  1585 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1586 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1587 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1588 be a tuple pattern.
  1589 
  1590 Some new syntax forms are available:
  1591 
  1592   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1593   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1594   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1595   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1596 
  1597 The latter form "\<Sum>x < k. e" used to be based on a separate
  1598 function "Summation", which has been discontinued.
  1599 
  1600 * theory Finite_Set: in structured induction proofs, the insert case
  1601 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1602 (insert F x)'.
  1603 
  1604 * The 'refute' command has been extended to support a much larger
  1605 fragment of HOL, including axiomatic type classes, constdefs and
  1606 typedefs, inductive datatypes and recursion.
  1607 
  1608 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1609 Requires zChaff with proof generation to be installed.  See
  1610 HOL/ex/SAT_Examples.thy for examples.
  1611 
  1612 * Datatype induction via method 'induct' now preserves the name of the
  1613 induction variable. For example, when proving P(xs::'a list) by
  1614 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1615 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1616 in unstructured proof scripts.
  1617 
  1618 * Reworked implementation of records.  Improved scalability for
  1619 records with many fields, avoiding performance problems for type
  1620 inference. Records are no longer composed of nested field types, but
  1621 of nested extension types. Therefore the record type only grows linear
  1622 in the number of extensions and not in the number of fields.  The
  1623 top-level (users) view on records is preserved.  Potential
  1624 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1625 old record representation. The type generated for a record is called
  1626 <record_name>_ext_type.
  1627 
  1628 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1629 proofs triggered by a record definition or a simproc (if
  1630 quick_and_dirty is enabled).  Definitions of large records can take
  1631 quite long.
  1632 
  1633 New simproc record_upd_simproc for simplification of multiple record
  1634 updates enabled by default.  Moreover, trivial updates are also
  1635 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1636 occasionally, since simplification is more powerful by default.
  1637 
  1638 * typedef: proper support for polymorphic sets, which contain extra
  1639 type-variables in the term.
  1640 
  1641 * Simplifier: automatically reasons about transitivity chains
  1642 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1643 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1644 old proofs break occasionally as simplification may now solve more
  1645 goals than previously.
  1646 
  1647 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1648 present.  Works for all partial orders (class "order"), in particular
  1649 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1650 just like y <= x.
  1651 
  1652 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1653 bound variable or a constant then the let is unfolded.  Otherwise
  1654 first a is simplified to b, and then f b is simplified to g. If
  1655 possible we abstract b from g arriving at "let x = b in h x",
  1656 otherwise we unfold the let and arrive at g.  The simproc can be
  1657 enabled/disabled by the reference use_let_simproc.  Potential
  1658 INCOMPATIBILITY since simplification is more powerful by default.
  1659 
  1660 * Classical reasoning: the meson method now accepts theorems as arguments.
  1661 
  1662 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1663 jobs to provide advice on the provability of subgoals.
  1664 
  1665 * Theory OrderedGroup and Ring_and_Field: various additions and
  1666 improvements to faciliate calculations involving equalities and
  1667 inequalities.
  1668 
  1669 The following theorems have been eliminated or modified
  1670 (INCOMPATIBILITY):
  1671 
  1672   abs_eq             now named abs_of_nonneg
  1673   abs_of_ge_0        now named abs_of_nonneg
  1674   abs_minus_eq       now named abs_of_nonpos
  1675   imp_abs_id         now named abs_of_nonneg
  1676   imp_abs_neg_id     now named abs_of_nonpos
  1677   mult_pos           now named mult_pos_pos
  1678   mult_pos_le        now named mult_nonneg_nonneg
  1679   mult_pos_neg_le    now named mult_nonneg_nonpos
  1680   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1681   mult_neg           now named mult_neg_neg
  1682   mult_neg_le        now named mult_nonpos_nonpos
  1683 
  1684 * Theory Parity: added rules for simplifying exponents.
  1685 
  1686 * Theory List:
  1687 
  1688 The following theorems have been eliminated or modified
  1689 (INCOMPATIBILITY):
  1690 
  1691   list_all_Nil       now named list_all.simps(1)
  1692   list_all_Cons      now named list_all.simps(2)
  1693   list_all_conv      now named list_all_iff
  1694   set_mem_eq         now named mem_iff
  1695 
  1696 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1697 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1698 
  1699 
  1700 *** HOL-Complex ***
  1701 
  1702 * Theory RealDef: better support for embedding natural numbers and
  1703 integers in the reals.
  1704 
  1705 The following theorems have been eliminated or modified
  1706 (INCOMPATIBILITY):
  1707 
  1708   exp_ge_add_one_self  now requires no hypotheses
  1709   real_of_int_add      reversed direction of equality (use [symmetric])
  1710   real_of_int_minus    reversed direction of equality (use [symmetric])
  1711   real_of_int_diff     reversed direction of equality (use [symmetric])
  1712   real_of_int_mult     reversed direction of equality (use [symmetric])
  1713 
  1714 * Theory RComplete: expanded support for floor and ceiling functions.
  1715 
  1716 * Theory Ln is new, with properties of the natural logarithm
  1717 
  1718 * Hyperreal: There is a new type constructor "star" for making
  1719 nonstandard types.  The old type names are now type synonyms:
  1720 
  1721   hypreal = real star
  1722   hypnat = nat star
  1723   hcomplex = complex star
  1724 
  1725 * Hyperreal: Many groups of similarly-defined constants have been
  1726 replaced by polymorphic versions (INCOMPATIBILITY):
  1727 
  1728   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1729 
  1730   starset      <-- starsetNat, starsetC
  1731   *s*          <-- *sNat*, *sc*
  1732   starset_n    <-- starsetNat_n, starsetC_n
  1733   *sn*         <-- *sNatn*, *scn*
  1734   InternalSets <-- InternalNatSets, InternalCSets
  1735 
  1736   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1737   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1738   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1739   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1740   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1741 
  1742 * Hyperreal: Many type-specific theorems have been removed in favor of
  1743 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1744 
  1745   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1746   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1747   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1748   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1749   right_minus <-- hypreal_add_minus
  1750   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1751   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1752   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1753   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1754   mult_1_right <-- hcomplex_mult_one_right
  1755   mult_zero_left <-- hcomplex_mult_zero_left
  1756   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1757   right_distrib <-- hypnat_add_mult_distrib2
  1758   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1759   right_inverse <-- hypreal_mult_inverse
  1760   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1761   order_refl <-- {hypreal,hypnat}_le_refl
  1762   order_trans <-- {hypreal,hypnat}_le_trans
  1763   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1764   order_less_le <-- {hypreal,hypnat}_less_le
  1765   linorder_linear <-- {hypreal,hypnat}_le_linear
  1766   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1767   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1768   add_nonneg_nonneg <-- hypreal_le_add_order
  1769 
  1770 * Hyperreal: Separate theorems having to do with type-specific
  1771 versions of constants have been merged into theorems that apply to the
  1772 new polymorphic constants (INCOMPATIBILITY):
  1773 
  1774   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1775   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1776   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1777   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1778   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1779   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1780   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1781   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1782   STAR_diff <-- {STAR,STARC}_diff
  1783   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1784     STARC_hcomplex_of_complex}_image_subset
  1785   starset_n_Un <-- starset{Nat,C}_n_Un
  1786   starset_n_Int <-- starset{Nat,C}_n_Int
  1787   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1788   starset_n_diff <-- starset{Nat,C}_n_diff
  1789   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1790   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1791   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1792   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1793   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1794   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1795   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1796   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1797   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1798   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1799   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1800   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1801   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1802   starfun_diff <-- starfun{C,RC,CR}_diff
  1803   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1804   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1805   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1806   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1807   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1808   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1809   starfun_Id <-- starfunC_Id
  1810   starfun_approx <-- starfun{Nat,CR}_approx
  1811   starfun_capprox <-- starfun{C,RC}_capprox
  1812   starfun_abs <-- starfunNat_rabs
  1813   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1814   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1815   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1816   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1817   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1818   starfun_add_approx <-- starfunCR_add_approx
  1819   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1820   starfun_divide <-- starfun{C,CR,RC}_divide
  1821   starfun_n <-- starfun{Nat,C}_n
  1822   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1823   starfun_n_add <-- starfun{Nat,C}_n_add
  1824   starfun_n_add_minus <-- starfunNat_n_add_minus
  1825   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1826   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1827   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1828 
  1829   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1830   star_n_minus <-- {hypreal,hcomplex}_minus
  1831   star_n_diff <-- {hypreal,hcomplex}_diff
  1832   star_n_mult <-- {hypreal,hcomplex}_mult
  1833   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1834   star_n_le <-- {hypreal,hypnat}_le
  1835   star_n_less <-- {hypreal,hypnat}_less
  1836   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1837   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1838   star_n_abs <-- hypreal_hrabs
  1839   star_n_divide <-- hcomplex_divide
  1840 
  1841   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1842   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1843   star_of_diff <-- hypreal_of_real_diff
  1844   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1845   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1846   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1847   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1848   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1849   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1850   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1851   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1852   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1853   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1854   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1855   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1856   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1857   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1858   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1859   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1860   star_of_power <-- hypreal_of_real_power
  1861   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1862 
  1863 * Hyperreal: new method "transfer" that implements the transfer
  1864 principle of nonstandard analysis. With a subgoal that mentions
  1865 nonstandard types like "'a star", the command "apply transfer"
  1866 replaces it with an equivalent one that mentions only standard types.
  1867 To be successful, all free variables must have standard types; non-
  1868 standard variables must have explicit universal quantifiers.
  1869 
  1870 * Hyperreal: A theory of Taylor series.
  1871 
  1872 
  1873 *** HOLCF ***
  1874 
  1875 * Discontinued special version of 'constdefs' (which used to support
  1876 continuous functions) in favor of the general Pure one with full
  1877 type-inference.
  1878 
  1879 * New simplification procedure for solving continuity conditions; it
  1880 is much faster on terms with many nested lambda abstractions (cubic
  1881 instead of exponential time).
  1882 
  1883 * New syntax for domain package: selector names are now optional.
  1884 Parentheses should be omitted unless argument is lazy, for example:
  1885 
  1886   domain 'a stream = cons "'a" (lazy "'a stream")
  1887 
  1888 * New command 'fixrec' for defining recursive functions with pattern
  1889 matching; defining multiple functions with mutual recursion is also
  1890 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1891 sinr, or any data constructor defined by the domain package. The given
  1892 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1893 syntax and examples.
  1894 
  1895 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1896 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1897 but the proof obligation additionally includes an admissibility
  1898 requirement. The packages generate instances of class cpo or pcpo,
  1899 with continuity and strictness theorems for Rep and Abs.
  1900 
  1901 * HOLCF: Many theorems have been renamed according to a more standard naming
  1902 scheme (INCOMPATIBILITY):
  1903 
  1904   foo_inject:  "foo$x = foo$y ==> x = y"
  1905   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1906   foo_less:    "(foo$x << foo$y) = (x << y)"
  1907   foo_strict:  "foo$UU = UU"
  1908   foo_defined: "... ==> foo$x ~= UU"
  1909   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1910 
  1911 
  1912 *** ZF ***
  1913 
  1914 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1915 including the First Isomorphism Theorem (on quotienting by the kernel
  1916 of a homomorphism).
  1917 
  1918 * ZF/Simplifier: install second copy of type solver that actually
  1919 makes use of TC rules declared to Isar proof contexts (or locales);
  1920 the old version is still required for ML proof scripts.
  1921 
  1922 
  1923 *** Cube ***
  1924 
  1925 * Converted to Isar theory format; use locales instead of axiomatic
  1926 theories.
  1927 
  1928 
  1929 *** ML ***
  1930 
  1931 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1932 for ||>, ||>>, |>>,
  1933 
  1934 * Pure/library.ML no longer defines its own option datatype, but uses
  1935 that of the SML basis, which has constructors NONE and SOME instead of
  1936 None and Some, as well as exception Option.Option instead of OPTION.
  1937 The functions the, if_none, is_some, is_none have been adapted
  1938 accordingly, while Option.map replaces apsome.
  1939 
  1940 * Pure/library.ML: the exception LIST has been given up in favour of
  1941 the standard exceptions Empty and Subscript, as well as
  1942 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1943 superceded by the standard hd and tl functions etc.
  1944 
  1945 A number of basic list functions are no longer exported to the ML
  1946 toplevel, as they are variants of predefined functions.  The following
  1947 suggests how one can translate existing code:
  1948 
  1949     rev_append xs ys = List.revAppend (xs, ys)
  1950     nth_elem (i, xs) = List.nth (xs, i)
  1951     last_elem xs = List.last xs
  1952     flat xss = List.concat xss
  1953     seq fs = List.app fs
  1954     partition P xs = List.partition P xs
  1955     mapfilter f xs = List.mapPartial f xs
  1956 
  1957 * Pure/library.ML: several combinators for linear functional
  1958 transformations, notably reverse application and composition:
  1959 
  1960   x |> f                f #> g
  1961   (x, y) |-> f          f #-> g
  1962 
  1963 * Pure/library.ML: introduced/changed precedence of infix operators:
  1964 
  1965   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1966   infix 2 ?;
  1967   infix 3 o oo ooo oooo;
  1968   infix 4 ~~ upto downto;
  1969 
  1970 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1971 infix operators.
  1972 
  1973 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1974 fold_map support linear functional transformations and nesting.  For
  1975 example:
  1976 
  1977   fold f [x1, ..., xN] y =
  1978     y |> f x1 |> ... |> f xN
  1979 
  1980   (fold o fold) f [xs1, ..., xsN] y =
  1981     y |> fold f xs1 |> ... |> fold f xsN
  1982 
  1983   fold f [x1, ..., xN] =
  1984     f x1 #> ... #> f xN
  1985 
  1986   (fold o fold) f [xs1, ..., xsN] =
  1987     fold f xs1 #> ... #> fold f xsN
  1988 
  1989 * Pure/library.ML: the following selectors on type 'a option are
  1990 available:
  1991 
  1992   the:               'a option -> 'a  (*partial*)
  1993   these:             'a option -> 'a  where 'a = 'b list
  1994   the_default: 'a -> 'a option -> 'a
  1995   the_list:          'a option -> 'a list
  1996 
  1997 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1998 basic operations for association lists, following natural argument
  1999 order; moreover the explicit equality predicate passed here avoids
  2000 potentially expensive polymorphic runtime equality checks.
  2001 The old functions may be expressed as follows:
  2002 
  2003   assoc = uncurry (AList.lookup (op =))
  2004   assocs = these oo AList.lookup (op =)
  2005   overwrite = uncurry (AList.update (op =)) o swap
  2006 
  2007 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2008 
  2009   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2010   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2011 
  2012 replacing make_keylist and keyfilter (occassionally used)
  2013 Naive rewrites:
  2014 
  2015   make_keylist = AList.make
  2016   keyfilter = AList.find (op =)
  2017 
  2018 * eq_fst and eq_snd now take explicit equality parameter, thus
  2019   avoiding eqtypes. Naive rewrites:
  2020 
  2021     eq_fst = eq_fst (op =)
  2022     eq_snd = eq_snd (op =)
  2023 
  2024 * Removed deprecated apl and apr (rarely used).
  2025   Naive rewrites:
  2026 
  2027     apl (n, op) =>>= curry op n
  2028     apr (op, m) =>>= fn n => op (n, m)
  2029 
  2030 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2031 provides a reasonably efficient light-weight implementation of sets as
  2032 lists.
  2033 
  2034 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2035 few new operations; existing lookup and update are now curried to
  2036 follow natural argument order (for use with fold etc.);
  2037 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2038 
  2039 * Pure/General: output via the Isabelle channels of
  2040 writeln/warning/error etc. is now passed through Output.output, with a
  2041 hook for arbitrary transformations depending on the print_mode
  2042 (cf. Output.add_mode -- the first active mode that provides a output
  2043 function wins).  Already formatted output may be embedded into further
  2044 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2045 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2046 accommodate easy composition of diagnostic messages etc.  Programmers
  2047 rarely need to care about Output.output or Output.raw at all, with
  2048 some notable exceptions: Output.output is required when bypassing the
  2049 standard channels (writeln etc.), or in token translations to produce
  2050 properly formatted results; Output.raw is required when capturing
  2051 already output material that will eventually be presented to the user
  2052 a second time.  For the default print mode, both Output.output and
  2053 Output.raw have no effect.
  2054 
  2055 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2056 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2057 cumulative results are displayed at the end of a batch session.
  2058 
  2059 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2060 replaced by File.platform_path and File.shell_path (with appropriate
  2061 hooks).  This provides a clean interface for unusual systems where the
  2062 internal and external process view of file names are different.
  2063 
  2064 * Pure: more efficient orders for basic syntactic entities: added
  2065 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2066 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2067 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2068 orders now -- potential INCOMPATIBILITY for code that depends on a
  2069 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2070 Library.sort_strings on result).
  2071 
  2072 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2073 fold_types traverse types/terms from left to right, observing natural
  2074 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2075 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2076 
  2077 * Pure: name spaces have been refined, with significant changes of the
  2078 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2079 to extern(_table).  The plain name entry path is superceded by a
  2080 general 'naming' context, which also includes the 'policy' to produce
  2081 a fully qualified name and external accesses of a fully qualified
  2082 name; NameSpace.extend is superceded by context dependent
  2083 Sign.declare_name.  Several theory and proof context operations modify
  2084 the naming context.  Especially note Theory.restore_naming and
  2085 ProofContext.restore_naming to get back to a sane state; note that
  2086 Theory.add_path is no longer sufficient to recover from
  2087 Theory.absolute_path in particular.
  2088 
  2089 * Pure: new flags short_names (default false) and unique_names
  2090 (default true) for controlling output of qualified names.  If
  2091 short_names is set, names are printed unqualified.  If unique_names is
  2092 reset, the name prefix is reduced to the minimum required to achieve
  2093 the original result when interning again, even if there is an overlap
  2094 with earlier declarations.
  2095 
  2096 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2097 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2098 (useful for printing error messages).  INCOMPATIBILITY.
  2099 
  2100 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2101 Theory.theory are now identified, referring to the universal
  2102 Context.theory (see Pure/context.ML).  Actual signature and theory
  2103 content is managed as theory data.  The old code and interfaces were
  2104 spread over many files and structures; the new arrangement introduces
  2105 considerable INCOMPATIBILITY to gain more clarity:
  2106 
  2107   Context -- theory management operations (name, identity, inclusion,
  2108     parents, ancestors, merge, etc.), plus generic theory data;
  2109 
  2110   Sign -- logical signature and syntax operations (declaring consts,
  2111     types, etc.), plus certify/read for common entities;
  2112 
  2113   Theory -- logical theory operations (stating axioms, definitions,
  2114     oracles), plus a copy of logical signature operations (consts,
  2115     types, etc.); also a few basic management operations (Theory.copy,
  2116     Theory.merge, etc.)
  2117 
  2118 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2119 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2120 for convenience -- they merely return the theory.
  2121 
  2122 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2123 
  2124 * Pure: the Isar proof context type is already defined early in Pure
  2125 as Context.proof (note that ProofContext.context and Proof.context are
  2126 aliases, where the latter is the preferred name).  This enables other
  2127 Isabelle components to refer to that type even before Isar is present.
  2128 
  2129 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2130 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2131 any of these kinds.  For example, Sign.intern typeK is now
  2132 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2133 Theory.hide_types.  Also note that former
  2134 Theory.hide_classes/types/consts are now
  2135 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2136 internalize their arguments!  INCOMPATIBILITY.
  2137 
  2138 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2139 datatype thmref (with constructors Name and NameSelection) instead of
  2140 plain string -- INCOMPATIBILITY;
  2141 
  2142 * Pure: cases produced by proof methods specify options, where NONE
  2143 means to remove case bindings -- INCOMPATIBILITY in
  2144 (RAW_)METHOD_CASES.
  2145 
  2146 * Pure: the following operations retrieve axioms or theorems from a
  2147 theory node or theory hierarchy, respectively:
  2148 
  2149   Theory.axioms_of: theory -> (string * term) list
  2150   Theory.all_axioms_of: theory -> (string * term) list
  2151   PureThy.thms_of: theory -> (string * thm) list
  2152   PureThy.all_thms_of: theory -> (string * thm) list
  2153 
  2154 * Pure: print_tac now outputs the goal through the trace channel.
  2155 
  2156 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2157 Reference Toplevel.debug (default false) controls detailed printing
  2158 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2159 controls execution profiling -- set to 1 for time and 2 for space
  2160 (both increase the runtime).
  2161 
  2162 * Isar session: The initial use of ROOT.ML is now always timed,
  2163 i.e. the log will show the actual process times, in contrast to the
  2164 elapsed wall-clock time that the outer shell wrapper produces.
  2165 
  2166 * Simplifier: improved handling of bound variables (nameless
  2167 representation, avoid allocating new strings).  Simprocs that invoke
  2168 the Simplifier recursively should use Simplifier.inherit_bounds to
  2169 avoid local name clashes.  Failure to do so produces warnings
  2170 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2171 for further details.
  2172 
  2173 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2174 bindings for all theorems stored within a given theory; this may help
  2175 in porting non-Isar theories to Isar ones, while keeping ML proof
  2176 scripts for the time being.
  2177 
  2178 * ML operator HTML.with_charset specifies the charset begin used for
  2179 generated HTML files.  For example:
  2180 
  2181   HTML.with_charset "utf-8" use_thy "Hebrew";
  2182   HTML.with_charset "utf-8" use_thy "Chinese";
  2183 
  2184 
  2185 *** System ***
  2186 
  2187 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2188 isabelle, isatool etc.).
  2189 
  2190 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2191 isatool doc, isatool mkdir, display_drafts etc.).
  2192 
  2193 * isatool usedir: option -f allows specification of the ML file to be
  2194 used by Isabelle; default is ROOT.ML.
  2195 
  2196 * New isatool version outputs the version identifier of the Isabelle
  2197 distribution being used.
  2198 
  2199 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2200 (containing Boolean satisfiability problems) into Isabelle/HOL
  2201 theories.
  2202 
  2203 
  2204 
  2205 New in Isabelle2004 (April 2004)
  2206 --------------------------------
  2207 
  2208 *** General ***
  2209 
  2210 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2211   Replaces linorder.ML.
  2212 
  2213 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2214   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2215   (\<a>...\<z>), are now considered normal letters, and can therefore
  2216   be used anywhere where an ASCII letter (a...zA...Z) has until
  2217   now. COMPATIBILITY: This obviously changes the parsing of some
  2218   terms, especially where a symbol has been used as a binder, say
  2219   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2220   as an identifier.  Fix it by inserting a space around former
  2221   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2222   existing theory and ML files.
  2223 
  2224 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2225 
  2226 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2227   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2228   a normal (but invisible) letter. For multiple letter subscripts repeat
  2229   \<^isub> like this: x\<^isub>1\<^isub>2.
  2230 
  2231 * Pure: There are now sub-/superscripts that can span more than one
  2232   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2233   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2234   superscript. The new control characters are not identifier parts.
  2235 
  2236 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2237   content of "..." to the latex file instead of \isacntrl... . The "..."
  2238   may consist of any printable characters excluding the end bracket >.
  2239 
  2240 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2241   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2242   declare constants "final", which prevents their being given a definition
  2243   later.  It is useful for constants whose behaviour is fixed axiomatically
  2244   rather than definitionally, such as the meta-logic connectives.
  2245 
  2246 * Pure: 'instance' now handles general arities with general sorts
  2247   (i.e. intersections of classes),
  2248 
  2249 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2250   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2251   It can be changed to alter the colors/layout of generated pages.
  2252 
  2253 
  2254 *** Isar ***
  2255 
  2256 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2257   cut_tac, subgoal_tac and thin_tac:
  2258   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2259     locales are no longer forced to write Isar proof scripts.
  2260     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2261     emulations.
  2262   - INCOMPATIBILITY: names of variables to be instantiated may no
  2263     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2264     This is consistent with the instantiation attribute "where".
  2265 
  2266 * Attributes "where" and "of":
  2267   - Now take type variables of instantiated theorem into account when reading
  2268     the instantiation string.  This fixes a bug that caused instantiated
  2269     theorems to have too special types in some circumstances.
  2270   - "where" permits explicit instantiations of type variables.
  2271 
  2272 * Calculation commands "moreover" and "also" no longer interfere with
  2273   current facts ("this"), admitting arbitrary combinations with "then"
  2274   and derived forms.
  2275 
  2276 * Locales:
  2277   - Goal statements involving the context element "includes" no longer
  2278     generate theorems with internal delta predicates (those ending on
  2279     "_axioms") in the premise.
  2280     Resolve particular premise with <locale>.intro to obtain old form.
  2281   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2282     specification and "includes" elements in goal statement.
  2283   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2284     [intro?] and [elim?] (respectively) by default.
  2285   - Experimental command for instantiation of locales in proof contexts:
  2286         instantiate <label>[<attrs>]: <loc>
  2287     Instantiates locale <loc> and adds all its theorems to the current context
  2288     taking into account their attributes.  Label and attrs are optional
  2289     modifiers, like in theorem declarations.  If present, names of
  2290     instantiated theorems are qualified with <label>, and the attributes
  2291     <attrs> are applied after any attributes these theorems might have already.
  2292       If the locale has assumptions, a chained fact of the form
  2293     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2294     are derived.  The command does not support old-style locales declared
  2295     with "locale (open)".
  2296       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2297 
  2298 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2299   (Isar) contexts.
  2300 
  2301 
  2302 *** HOL ***
  2303 
  2304 * Proof import: new image HOL4 contains the imported library from
  2305   the HOL4 system with about 2500 theorems. It is imported by
  2306   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2307   can be used like any other Isabelle image.  See
  2308   HOL/Import/HOL/README for more information.
  2309 
  2310 * Simplifier:
  2311   - Much improved handling of linear and partial orders.
  2312     Reasoners for linear and partial orders are set up for type classes
  2313     "linorder" and "order" respectively, and are added to the default simpset
  2314     as solvers.  This means that the simplifier can build transitivity chains
  2315     to solve goals from the assumptions.
  2316   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2317     of blast or auto after simplification become unnecessary because the goal
  2318     is solved by simplification already.
  2319 
  2320 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2321     all proved in axiomatic type classes for semirings, rings and fields.
  2322 
  2323 * Numerics:
  2324   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2325     now formalized using the Ring_and_Field theory mentioned above.
  2326   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2327     than before, because now they are set up once in a generic manner.
  2328   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2329     Look for the general versions in Ring_and_Field (and Power if they concern
  2330     exponentiation).
  2331 
  2332 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2333 
  2334 * Records:
  2335   - Record types are now by default printed with their type abbreviation
  2336     instead of the list of all field types. This can be configured via
  2337     the reference "print_record_type_abbr".
  2338   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2339     (not enabled by default).
  2340   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2341     EX x. x = sel r to True (not enabled by default).
  2342   - Tactic "record_split_simp_tac" to split and simplify records added.
  2343 
  2344 * 'specification' command added, allowing for definition by
  2345   specification.  There is also an 'ax_specification' command that
  2346   introduces the new constants axiomatically.
  2347 
  2348 * arith(_tac) is now able to generate counterexamples for reals as well.
  2349 
  2350 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2351 
  2352 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2353   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2354 
  2355 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2356   matrix theory to linear programming.
  2357 
  2358 * Unions and Intersections:
  2359   The latex output syntax of UN and INT has been changed
  2360   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2361   i.e. the index formulae has become a subscript.
  2362   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2363 
  2364 * Unions and Intersections over Intervals:
  2365   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2366   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2367   like in normal math, and corresponding versions for < and for intersection.
  2368 
  2369 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2370   lexicographic dictonary ordering has been added as "lexord".
  2371 
  2372 * ML: the legacy theory structures Int and List have been removed. They had
  2373   conflicted with ML Basis Library structures having the same names.
  2374 
  2375 * 'refute' command added to search for (finite) countermodels.  Only works
  2376   for a fragment of HOL.  The installation of an external SAT solver is
  2377   highly recommended.  See "HOL/Refute.thy" for details.
  2378 
  2379 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2380   formulae under an assignment of free variables to random values.
  2381   In contrast to 'refute', it can deal with inductive datatypes,
  2382   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2383   for examples.
  2384 
  2385 
  2386 *** HOLCF ***
  2387 
  2388 * Streams now come with concatenation and are part of the HOLCF image
  2389 
  2390 
  2391 
  2392 New in Isabelle2003 (May 2003)
  2393 ------------------------------
  2394 
  2395 *** General ***
  2396 
  2397 * Provers/simplifier:
  2398 
  2399   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2400     Assumptions are now subject to complete mutual simplification,
  2401     not just from left to right. The simplifier now preserves
  2402     the order of assumptions.
  2403 
  2404     Potential INCOMPATIBILITY:
  2405 
  2406     -- simp sometimes diverges where the old version did
  2407        not, e.g. invoking simp on the goal
  2408 
  2409         [| P (f x); y = x; f x = f y |] ==> Q
  2410 
  2411        now gives rise to the infinite reduction sequence
  2412 
  2413         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2414 
  2415        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2416        kind of problem.
  2417 
  2418     -- Tactics combining classical reasoner and simplification (such as auto)
  2419        are also affected by this change, because many of them rely on
  2420        simp. They may sometimes diverge as well or yield a different numbers
  2421        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2422        in case of problems. Sometimes subsequent calls to the classical
  2423        reasoner will fail because a preceeding call to the simplifier too
  2424        eagerly simplified the goal, e.g. deleted redundant premises.
  2425 
  2426   - The simplifier trace now shows the names of the applied rewrite rules
  2427 
  2428   - You can limit the number of recursive invocations of the simplifier
  2429     during conditional rewriting (where the simplifie tries to solve the
  2430     conditions before applying the rewrite rule):
  2431     ML "simp_depth_limit := n"
  2432     where n is an integer. Thus you can force termination where previously
  2433     the simplifier would diverge.
  2434 
  2435   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2436 
  2437   - No longer aborts on failed congruence proof.  Instead, the
  2438     congruence is ignored.
  2439 
  2440 * Pure: New generic framework for extracting programs from constructive
  2441   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2442   as HOL/Extraction for some case studies.
  2443 
  2444 * Pure: The main goal of the proof state is no longer shown by default, only
  2445 the subgoals. This behaviour is controlled by a new flag.
  2446    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2447 (ML: Proof.show_main_goal).
  2448 
  2449 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2450 rules whose conclusion matches subgoal 1:
  2451       PG menu: Isabelle/Isar -> Show me -> matching rules
  2452 The rules are ordered by how closely they match the subgoal.
  2453 In particular, rules that solve a subgoal outright are displayed first
  2454 (or rather last, the way they are printed).
  2455 (ML: ProofGeneral.print_intros())
  2456 
  2457 * Pure: New flag trace_unify_fail causes unification to print
  2458 diagnostic information (PG: in trace buffer) when it fails. This is
  2459 useful for figuring out why single step proofs like rule, erule or
  2460 assumption failed.
  2461 
  2462 * Pure: Locale specifications now produce predicate definitions
  2463 according to the body of text (covering assumptions modulo local
  2464 definitions); predicate "loc_axioms" covers newly introduced text,
  2465 while "loc" is cumulative wrt. all included locale expressions; the
  2466 latter view is presented only on export into the global theory
  2467 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2468 on the old view without predicates;
  2469 
  2470 * Pure: predefined locales "var" and "struct" are useful for sharing
  2471 parameters (as in CASL, for example); just specify something like
  2472 ``var x + var y + struct M'' as import;
  2473 
  2474 * Pure: improved thms_containing: proper indexing of facts instead of
  2475 raw theorems; check validity of results wrt. current name space;
  2476 include local facts of proof configuration (also covers active
  2477 locales), cover fixed variables in index; may use "_" in term
  2478 specification; an optional limit for the number of printed facts may
  2479 be given (the default is 40);
  2480 
  2481 * Pure: disallow duplicate fact bindings within new-style theory files
  2482 (batch-mode only);
  2483 
  2484 * Provers: improved induct method: assumptions introduced by case
  2485 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2486 the goal statement); "foo" still refers to all facts collectively;
  2487 
  2488 * Provers: the function blast.overloaded has been removed: all constants
  2489 are regarded as potentially overloaded, which improves robustness in exchange
  2490 for slight decrease in efficiency;
  2491 
  2492 * Provers/linorder: New generic prover for transitivity reasoning over
  2493 linear orders.  Note: this prover is not efficient!
  2494 
  2495 * Isar: preview of problems to finish 'show' now produce an error
  2496 rather than just a warning (in interactive mode);
  2497 
  2498 
  2499 *** HOL ***
  2500 
  2501 * arith(_tac)
  2502 
  2503  - Produces a counter example if it cannot prove a goal.
  2504    Note that the counter example may be spurious if the goal is not a formula
  2505    of quantifier-free linear arithmetic.
  2506    In ProofGeneral the counter example appears in the trace buffer.
  2507 
  2508  - Knows about div k and mod k where k is a numeral of type nat or int.
  2509 
  2510  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2511    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2512    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2513 
  2514 * simp's arithmetic capabilities have been enhanced a bit: it now
  2515 takes ~= in premises into account (by performing a case split);
  2516 
  2517 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2518 are distributed over a sum of terms;
  2519 
  2520 * New tactic "trans_tac" and method "trans" instantiate
  2521 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2522 "<=", "<" and "=").
  2523 
  2524 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2525 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2526 
  2527 * 'typedef' command has new option "open" to suppress the set
  2528 definition;
  2529 
  2530 * functions Min and Max on finite sets have been introduced (theory
  2531 Finite_Set);
  2532 
  2533 * attribute [symmetric] now works for relations as well; it turns
  2534 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2535 
  2536 * induct over a !!-quantified statement (say !!x1..xn):
  2537   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2538 
  2539 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2540 %x. None. Warning: empty_def now refers to the previously hidden definition
  2541 of the empty set.
  2542 
  2543 * Algebra: formalization of classical algebra.  Intended as base for
  2544 any algebraic development in Isabelle.  Currently covers group theory
  2545 (up to Sylow's theorem) and ring theory (Universal Property of
  2546 Univariate Polynomials).  Contributions welcome;
  2547 
  2548 * GroupTheory: deleted, since its material has been moved to Algebra;
  2549 
  2550 * Complex: new directory of the complex numbers with numeric constants,
  2551 nonstandard complex numbers, and some complex analysis, standard and
  2552 nonstandard (Jacques Fleuriot);
  2553 
  2554 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2555 
  2556 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2557 Fleuriot);
  2558 
  2559 * Real/HahnBanach: updated and adapted to locales;
  2560 
  2561 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2562 Gray and Kramer);
  2563 
  2564 * UNITY: added the Meier-Sanders theory of progress sets;
  2565 
  2566 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2567 as abstract algorithms, instantiated to the JVM;
  2568 
  2569 * Bali: Java source language formalization. Type system, operational
  2570 semantics, axiomatic semantics. Supported language features:
  2571 classes, interfaces, objects,virtual methods, static methods,
  2572 static/instance fields, arrays, access modifiers, definite
  2573 assignment, exceptions.
  2574 
  2575 
  2576 *** ZF ***
  2577 
  2578 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2579 universe, etc.);
  2580 
  2581 * Main ZF: virtually all theories converted to new-style format;
  2582 
  2583 
  2584 *** ML ***
  2585 
  2586 * Pure: Tactic.prove provides sane interface for internal proofs;
  2587 omits the infamous "standard" operation, so this is more appropriate
  2588 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2589 
  2590 * Pure: improved error reporting of simprocs;
  2591 
  2592 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2593 up simprocs;
  2594 
  2595 
  2596 *** Document preparation ***
  2597 
  2598 * uses \par instead of \\ for line breaks in theory text. This may
  2599 shift some page breaks in large documents. To get the old behaviour
  2600 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2601 
  2602 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2603 other packages
  2604 
  2605 * \<euro> now needs package babel/greek instead of marvosym (which
  2606 broke \Rightarrow)
  2607 
  2608 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2609 textcomp package)
  2610 
  2611 
  2612 
  2613 New in Isabelle2002 (March 2002)
  2614 --------------------------------
  2615 
  2616 *** Document preparation ***
  2617 
  2618 * greatly simplified document preparation setup, including more
  2619 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2620 instructive isatool mkdir; users should basically be able to get
  2621 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2622 users may run a separate document processing stage manually like this:
  2623 "isatool usedir -D output HOL Test && isatool document Test/output";
  2624 
  2625 * theory dependency graph may now be incorporated into documents;
  2626 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2627 with \includegraphics of LaTeX;
  2628 
  2629 * proper spacing of consecutive markup elements, especially text
  2630 blocks after section headings;
  2631 
  2632 * support bold style (for single symbols only), input syntax is like
  2633 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2634 
  2635 * \<bullet> is now output as bold \cdot by default, which looks much
  2636 better in printed text;
  2637 
  2638 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2639 note that these symbols are currently unavailable in Proof General /
  2640 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2641 
  2642 * isatool latex no longer depends on changed TEXINPUTS, instead
  2643 isatool document copies the Isabelle style files to the target
  2644 location;
  2645 
  2646 
  2647 *** Isar ***
  2648 
  2649 * Pure/Provers: improved proof by cases and induction;
  2650   - 'case' command admits impromptu naming of parameters (such as
  2651     "case (Suc n)");
  2652   - 'induct' method divinates rule instantiation from the inductive
  2653     claim; no longer requires excessive ?P bindings for proper
  2654     instantiation of cases;
  2655   - 'induct' method properly enumerates all possibilities of set/type
  2656     rules; as a consequence facts may be also passed through *type*
  2657     rules without further ado;
  2658   - 'induct' method now derives symbolic cases from the *rulified*
  2659     rule (before it used to rulify cases stemming from the internal
  2660     atomized version); this means that the context of a non-atomic
  2661     statement becomes is included in the hypothesis, avoiding the
  2662     slightly cumbersome show "PROP ?case" form;
  2663   - 'induct' may now use elim-style induction rules without chaining
  2664     facts, using ``missing'' premises from the goal state; this allows
  2665     rules stemming from inductive sets to be applied in unstructured
  2666     scripts, while still benefitting from proper handling of non-atomic
  2667     statements; NB: major inductive premises need to be put first, all
  2668     the rest of the goal is passed through the induction;
  2669   - 'induct' proper support for mutual induction involving non-atomic
  2670     rule statements (uses the new concept of simultaneous goals, see
  2671     below);
  2672   - append all possible rule selections, but only use the first
  2673     success (no backtracking);
  2674   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2675   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2676   - added 'print_induct_rules' (covered by help item in recent Proof
  2677     General versions);
  2678   - moved induct/cases attributes to Pure, methods to Provers;
  2679   - generic method setup instantiated for FOL and HOL;
  2680 
  2681 * Pure: support multiple simultaneous goal statements, for example
  2682 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2683 meta-level mechanism, this acts as if several individual goals had
  2684 been stated separately; in particular common proof methods need to be
  2685 repeated in order to cover all claims; note that a single elimination
  2686 step is *not* sufficient to establish the two conjunctions, so this
  2687 fails:
  2688 
  2689   assume "A & B" then have A and B ..   (*".." fails*)
  2690 
  2691 better use "obtain" in situations as above; alternative refer to
  2692 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2693 
  2694 * Pure: proper integration with ``locales''; unlike the original
  2695 version by Florian Kammller, Isar locales package high-level proof
  2696 contexts rather than raw logical ones (e.g. we admit to include
  2697 attributes everywhere); operations on locales include merge and
  2698 rename; support for implicit arguments (``structures''); simultaneous
  2699 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2700 some examples;
  2701 
  2702 * Pure: the following commands have been ``localized'', supporting a
  2703 target locale specification "(in name)": 'lemma', 'theorem',
  2704 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2705 stored both within the locale and at the theory level (exported and
  2706 qualified by the locale name);
  2707 
  2708 * Pure: theory goals may now be specified in ``long'' form, with
  2709 ad-hoc contexts consisting of arbitrary locale elements. for example
  2710 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2711 definitions may be given, too); the result is a meta-level rule with
  2712 the context elements being discharged in the obvious way;
  2713 
  2714 * Pure: new proof command 'using' allows to augment currently used
  2715 facts after a goal statement ('using' is syntactically analogous to
  2716 'apply', but acts on the goal's facts only); this allows chained facts
  2717 to be separated into parts given before and after a claim, as in
  2718 ``from a and b have C using d and e <proof>'';
  2719 
  2720 * Pure: renamed "antecedent" case to "rule_context";
  2721 
  2722 * Pure: new 'judgment' command records explicit information about the
  2723 object-logic embedding (used by several tools internally); no longer
  2724 use hard-wired "Trueprop";
  2725 
  2726 * Pure: added 'corollary' command;
  2727 
  2728 * Pure: fixed 'token_translation' command;
  2729 
  2730 * Pure: removed obsolete 'exported' attribute;
  2731 
  2732 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2733 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2734 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2735 
  2736 * Pure: method 'atomize' presents local goal premises as object-level
  2737 statements (atomic meta-level propositions); setup controlled via
  2738 rewrite rules declarations of 'atomize' attribute; example
  2739 application: 'induct' method with proper rule statements in improper
  2740 proof *scripts*;
  2741 
  2742 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2743 now consider the syntactic context of assumptions, giving a better
  2744 chance to get type-inference of the arguments right (this is
  2745 especially important for locales);
  2746 
  2747 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2748 mode;
  2749 
  2750 * Pure/obtain: the formal conclusion "thesis", being marked as
  2751 ``internal'', may no longer be reference directly in the text;
  2752 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2753 situations;
  2754 
  2755 * Pure: generic 'sym' attribute which declares a rule both as pure
  2756 'elim?' and for the 'symmetric' operation;
  2757 
  2758 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2759 text; the fixed correlation with particular command syntax has been
  2760 discontinued;
  2761 
  2762 * Pure: new method 'rules' is particularly well-suited for proof
  2763 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2764 but often produces more compact proof terms with less detours;
  2765 
  2766 * Pure/Provers/classical: simplified integration with pure rule
  2767 attributes and methods; the classical "intro?/elim?/dest?"
  2768 declarations coincide with the pure ones; the "rule" method no longer
  2769 includes classically swapped intros; "intro" and "elim" methods no
  2770 longer pick rules from the context; also got rid of ML declarations
  2771 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2772 INCOMPATIBILITY;
  2773 
  2774 * Provers/classical: attribute 'swapped' produces classical inversions
  2775 of introduction rules;
  2776 
  2777 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2778 rules instead of full simplifier context; 'iff' attribute handles
  2779 conditional rules;
  2780 
  2781 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2782 
  2783 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2784 "(permissive)" option to recover old behavior;
  2785 
  2786 * HOL: 'inductive' no longer features separate (collective) attributes
  2787 for 'intros' (was found too confusing);
  2788 
  2789 * HOL: properly declared induction rules less_induct and
  2790 wf_induct_rule;
  2791 
  2792 
  2793 *** HOL ***
  2794 
  2795 * HOL: moved over to sane numeral syntax; the new policy is as
  2796 follows:
  2797 
  2798   - 0 and 1 are polymorphic constants, which are defined on any
  2799   numeric type (nat, int, real etc.);
  2800 
  2801   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2802   binary representation internally;
  2803 
  2804   - type nat has special constructor Suc, and generally prefers Suc 0
  2805   over 1::nat and Suc (Suc 0) over 2::nat;
  2806 
  2807 This change may cause significant problems of INCOMPATIBILITY; here
  2808 are some hints on converting existing sources:
  2809 
  2810   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2811   entities, so expressions involving "-" (unary or binary minus) need
  2812   to be spaced properly;
  2813 
  2814   - existing occurrences of "1" may need to be constraint "1::nat" or
  2815   even replaced by Suc 0; similar for old "2";
  2816 
  2817   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2818 
  2819   - remove all special provisions on numerals in proofs;
  2820 
  2821 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2822 representation (depends on bin_arith_simps in the default context);
  2823 
  2824 * HOL: symbolic syntax for x^2 (numeral 2);
  2825 
  2826 * HOL: the class of all HOL types is now called "type" rather than
  2827 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2828 in axclass/classes, instance/arities, and (usually rare) occurrences
  2829 in typings (of consts etc.); internally the class is called
  2830 "HOL.type", ML programs should refer to HOLogic.typeS;
  2831 
  2832 * HOL/record package improvements:
  2833   - new derived operations "fields" to build a partial record section,
  2834     "extend" to promote a fixed record to a record scheme, and
  2835     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2836     declared as simp by default;
  2837   - shared operations ("more", "fields", etc.) now need to be always
  2838     qualified) --- potential INCOMPATIBILITY;
  2839   - removed "make_scheme" operations (use "make" with "extend") --
  2840     INCOMPATIBILITY;
  2841   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2842   - provides cases/induct rules for use with corresponding Isar
  2843     methods (for concrete records, record schemes, concrete more
  2844     parts, and schematic more parts -- in that order);
  2845   - internal definitions directly based on a light-weight abstract
  2846     theory of product types over typedef rather than datatype;
  2847 
  2848 * HOL: generic code generator for generating executable ML code from
  2849 specifications; specific support for HOL constructs such as inductive
  2850 datatypes and sets, as well as recursive functions; can be invoked
  2851 via 'generate_code' theory section;
  2852 
  2853 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2854 
  2855 * HOL: consolidated and renamed several theories.  In particular:
  2856         Ord.thy has been absorbed into HOL.thy
  2857         String.thy has been absorbed into List.thy
  2858 
  2859 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2860 (beware of argument permutation!);
  2861 
  2862 * HOL: linorder_less_split superseded by linorder_cases;
  2863 
  2864 * HOL/List: "nodups" renamed to "distinct";
  2865 
  2866 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2867 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2868   - Ex_def has changed, now need to use some_eq_ex
  2869 
  2870 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2871 in this (rare) case use:
  2872 
  2873   delSWrapper "split_all_tac"
  2874   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2875 
  2876 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2877 MAY FAIL;
  2878 
  2879 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2880 Isabelle's type classes, ^ on functions and relations has too general
  2881 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2882 necessary to attach explicit type constraints;
  2883 
  2884 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2885 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2886 renamed accordingly (eg "compI" -> "rel_compI").
  2887 
  2888 * HOL: syntax translations now work properly with numerals and records
  2889 expressions;
  2890 
  2891 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2892 of "lam" -- INCOMPATIBILITY;
  2893 
  2894 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2895 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2896 renamed "Product_Type.unit";
  2897 
  2898 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2899 
  2900 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2901 the "cases" method);
  2902 
  2903 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2904 Florian Kammller);
  2905 
  2906 * HOL/IMP: updated and converted to new-style theory format; several
  2907 parts turned into readable document, with proper Isar proof texts and
  2908 some explanations (by Gerwin Klein);
  2909 
  2910 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2911 
  2912 * HOL-Hyperreal is now a logic image;
  2913 
  2914 
  2915 *** HOLCF ***
  2916 
  2917 * Isar: consts/constdefs supports mixfix syntax for continuous
  2918 operations;
  2919 
  2920 * Isar: domain package adapted to new-style theory format, e.g. see
  2921 HOLCF/ex/Dnat.thy;
  2922 
  2923 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2924 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2925 lift.induct_tac, always use UU instead of Undef;
  2926 
  2927 * HOLCF/IMP: updated and converted to new-style theory;
  2928 
  2929 
  2930 *** ZF ***
  2931 
  2932 * Isar: proper integration of logic-specific tools and packages,
  2933 including theory commands '(co)inductive', '(co)datatype',
  2934 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2935 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2936 
  2937 * theory Main no longer includes AC; for the Axiom of Choice, base
  2938 your theory on Main_ZFC;
  2939 
  2940 * the integer library now covers quotients and remainders, with many
  2941 laws relating division to addition, multiplication, etc.;
  2942 
  2943 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2944 typeless version of the formalism;
  2945 
  2946 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2947 format;
  2948 
  2949 * ZF/Induct: new directory for examples of inductive definitions,
  2950 including theory Multiset for multiset orderings; converted to
  2951 new-style theory format;
  2952 
  2953 * ZF: many new theorems about lists, ordinals, etc.;
  2954 
  2955 
  2956 *** General ***
  2957 
  2958 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2959 variable proof controls level of detail: 0 = no proofs (only oracle
  2960 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2961 also ref manual for further ML interfaces;
  2962 
  2963 * Pure/axclass: removed obsolete ML interface
  2964 goal_subclass/goal_arity;
  2965 
  2966 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2967 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2968 separate tokens, so expressions involving minus need to be spaced
  2969 properly;
  2970 
  2971 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2972 rather than "infixl" or "infixr";
  2973 
  2974 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2975 sort constraint specifications in type inference; e.g. "x::_::foo"
  2976 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2977 type variable);
  2978 
  2979 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2980 control output of nested => (types); the default behavior is
  2981 "type_brackets";
  2982 
  2983 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2984 tokens into AST constants;
  2985 
  2986 * Pure/syntax: prefer later declarations of translations and print
  2987 translation functions; potential INCOMPATIBILITY: need to reverse
  2988 multiple declarations for same syntax element constant;
  2989 
  2990 * Pure/show_hyps reset by default (in accordance to existing Isar
  2991 practice);
  2992 
  2993 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2994 addSafter;
  2995 
  2996 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2997 as well;
  2998 
  2999 * system: tested support for MacOS X; should be able to get Isabelle +
  3000 Proof General to work in a plain Terminal after installing Poly/ML
  3001 (e.g. from the Isabelle distribution area) and GNU bash alone
  3002 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3003 support requires further installations, e.g. from
  3004 http://fink.sourceforge.net/);
  3005 
  3006 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3007 
  3008 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3009 of 40 MB), cf. ML_OPTIONS;
  3010 
  3011 * system: Proof General keywords specification is now part of the
  3012 Isabelle distribution (see etc/isar-keywords.el);
  3013 
  3014 * system: support for persistent Proof General sessions (refrain from
  3015 outdating all loaded theories on startup); user may create writable
  3016 logic images like this: ``isabelle -q HOL Test'';
  3017 
  3018 * system: smart selection of Isabelle process versus Isabelle
  3019 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3020 run both "isabelle" and "Isabelle" even if file names are badly
  3021 damaged (executable inspects the case of the first letter of its own
  3022 name); added separate "isabelle-process" and "isabelle-interface";
  3023 
  3024 * system: refrain from any attempt at filtering input streams; no
  3025 longer support ``8bit'' encoding of old isabelle font, instead proper
  3026 iso-latin characters may now be used; the related isatools
  3027 "symbolinput" and "nonascii" have disappeared as well;
  3028 
  3029 * system: removed old "xterm" interface (the print modes "xterm" and
  3030 "xterm_color" are still available for direct use in a suitable
  3031 terminal);
  3032 
  3033 
  3034 
  3035 New in Isabelle99-2 (February 2001)
  3036 -----------------------------------
  3037 
  3038 *** Overview of INCOMPATIBILITIES ***
  3039 
  3040 * HOL: please note that theories in the Library and elsewhere often use the
  3041 new-style (Isar) format; to refer to their theorems in an ML script you must
  3042 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3043 
  3044 * HOL: inductive package no longer splits induction rule aggressively,
  3045 but only as far as specified by the introductions given; the old
  3046 format may be recovered via ML function complete_split_rule or attribute
  3047 'split_rule (complete)';
  3048 
  3049 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3050 gfp_Tarski to gfp_unfold;
  3051 
  3052 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3053 
  3054 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3055 relation); infix "^^" has been renamed "``"; infix "``" has been
  3056 renamed "`"; "univalent" has been renamed "single_valued";
  3057 
  3058 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3059 operation;
  3060 
  3061 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3062 
  3063 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3064 
  3065 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3066 consequence, it is no longer monotonic wrt. the local goal context
  3067 (which is now passed through the inductive cases);
  3068 
  3069 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3070 \<gg> to \<ggreater>;
  3071 
  3072 
  3073 *** Document preparation ***
  3074 
  3075 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3076 available: are "it" for near math-mode best-style output, "sl" for
  3077 slanted text style, and "tt" for plain type-writer; if no
  3078 \isabellestyle command is given, output is according to slanted
  3079 type-writer);
  3080 
  3081 * support sub/super scripts (for single symbols only), input syntax is
  3082 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3083 
  3084 * some more standard symbols; see Appendix A of the system manual for
  3085 the complete list of symbols defined in isabellesym.sty;
  3086 
  3087 * improved isabelle style files; more abstract symbol implementation
  3088 (should now use \isamath{...} and \isatext{...} in custom symbol
  3089 definitions);
  3090 
  3091 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3092 state; Note that presentation of goal states does not conform to
  3093 actual human-readable proof documents.  Please do not include goal
  3094 states into document output unless you really know what you are doing!
  3095 
  3096 * proper indentation of antiquoted output with proportional LaTeX
  3097 fonts;
  3098 
  3099 * no_document ML operator temporarily disables LaTeX document
  3100 generation;
  3101 
  3102 * isatool unsymbolize tunes sources for plain ASCII communication;
  3103 
  3104 
  3105 *** Isar ***
  3106 
  3107 * Pure: Isar now suffers initial goal statements to contain unbound
  3108 schematic variables (this does not conform to actual readable proof
  3109 documents, due to unpredictable outcome and non-compositional proof
  3110 checking); users who know what they are doing may use schematic goals
  3111 for Prolog-style synthesis of proven results;
  3112 
  3113 * Pure: assumption method (an implicit finishing) now handles actual
  3114 rules as well;
  3115 
  3116 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3117 initial goal, declare "that" only as Pure intro (only for single
  3118 steps); the "that" rule assumption may now be involved in implicit
  3119 finishing, thus ".." becomes a feasible for trivial obtains;
  3120 
  3121 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3122 instance proofs may be performed by "..";
  3123 
  3124 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3125 statements as well;
  3126 
  3127 * Pure: more robust selection of calculational rules;
  3128 
  3129 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3130 rule (as well as the assumption rule);
  3131 
  3132 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3133 lemmas, using the graph browser tool;
  3134 
  3135 * Pure: predict failure of "show" in interactive mode;
  3136 
  3137 * Pure: 'thms_containing' now takes actual terms as arguments;
  3138 
  3139 * HOL: improved method 'induct' --- now handles non-atomic goals
  3140 (potential INCOMPATIBILITY); tuned error handling;
  3141 
  3142 * HOL: cases and induct rules now provide explicit hints about the
  3143 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3144 any remaining facts are inserted into the goal verbatim;
  3145 
  3146 * HOL: local contexts (aka cases) may now contain term bindings as
  3147 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3148 the result to be shown in each case;
  3149 
  3150 * HOL: added 'recdef_tc' command;
  3151 
  3152 * isatool convert assists in eliminating legacy ML scripts;
  3153 
  3154 
  3155 *** HOL ***
  3156 
  3157 * HOL/Library: a collection of generic theories to be used together
  3158 with main HOL; the theory loader path already includes this directory
  3159 by default; the following existing theories have been moved here:
  3160 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3161 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3162 
  3163 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3164 modelling and verification task performed in Isabelle/HOL +
  3165 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3166 
  3167 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3168 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3169 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3170 'domain', this makes the theory consistent with mathematical
  3171 literature;
  3172 
  3173 * HOL basics: added overloaded operations "inverse" and "divide"
  3174 (infix "/"), syntax for generic "abs" operation, generic summation
  3175 operator \<Sum>;
  3176 
  3177 * HOL/typedef: simplified package, provide more useful rules (see also
  3178 HOL/subset.thy);
  3179 
  3180 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3181 now expressed as a proper nested rule (old-style tactic scripts may
  3182 require atomize_strip_tac to cope with non-atomic premises);
  3183 
  3184 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3185 to "split_conv" (old name still available for compatibility);
  3186 
  3187 * HOL: improved concrete syntax for strings (e.g. allows translation
  3188 rules with string literals);
  3189 
  3190 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3191  and Fleuriot's mechanization of analysis, including the transcendental
  3192  functions for the reals;
  3193 
  3194 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3195 
  3196 
  3197 *** CTT ***
  3198 
  3199 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3200 "lam" is displayed as TWO lambda-symbols
  3201 
  3202 * CTT: theory Main now available, containing everything (that is, Bool
  3203 and Arith);
  3204 
  3205 
  3206 *** General ***
  3207 
  3208 * Pure: the Simplifier has been implemented properly as a derived rule
  3209 outside of the actual kernel (at last!); the overall performance
  3210 penalty in practical applications is about 50%, while reliability of
  3211 the Isabelle inference kernel has been greatly improved;
  3212 
  3213 * print modes "brackets" and "no_brackets" control output of nested =>
  3214 (types) and ==> (props); the default behaviour is "brackets";
  3215 
  3216 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3217 as assumptions as well;
  3218 
  3219 * system: support Poly/ML 4.0;
  3220 
  3221 * system: isatool install handles KDE version 1 or 2;
  3222 
  3223 
  3224 
  3225 New in Isabelle99-1 (October 2000)
  3226 ----------------------------------
  3227 
  3228 *** Overview of INCOMPATIBILITIES ***
  3229 
  3230 * HOL: simplification of natural numbers is much changed; to partly
  3231 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3232 issue the following ML commands:
  3233 
  3234   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3235   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3236 
  3237 * HOL: simplification no longer dives into case-expressions; this is
  3238 controlled by "t.weak_case_cong" for each datatype t;
  3239 
  3240 * HOL: nat_less_induct renamed to less_induct;
  3241 
  3242 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3243 fixsome to patch .thy and .ML sources automatically;
  3244 
  3245   select_equality  -> some_equality
  3246   select_eq_Ex     -> some_eq_ex
  3247   selectI2EX       -> someI2_ex
  3248   selectI2         -> someI2
  3249   selectI          -> someI
  3250   select1_equality -> some1_equality
  3251   Eps_sym_eq       -> some_sym_eq_trivial
  3252   Eps_eq           -> some_eq_trivial
  3253 
  3254 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3255 
  3256 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3257 instead);
  3258 
  3259 * HOL: the recursion equations generated by 'recdef' are now called
  3260 f.simps instead of f.rules;
  3261 
  3262 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3263 
  3264 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3265 sometimes be needed;
  3266 
  3267 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3268 
  3269 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3270 
  3271 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3272 product is now "<*>" instead of "Times"; the lexicographic product is
  3273 now "<*lex*>" instead of "**";
  3274 
  3275 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3276 of main HOL, but was unused); better use HOL's datatype package;
  3277 
  3278 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3279 the old syntax may be recovered as follows:
  3280 
  3281   syntax (symbols)
  3282     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3283       (infixl "\\<oplus>" 100)
  3284 
  3285 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3286 
  3287 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3288 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3289 internally;
  3290 
  3291 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3292 changed from A/r to A//r;
  3293 
  3294 * ZF: new treatment of arithmetic (nat & int) may break some old
  3295 proofs;
  3296 
  3297 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3298 rulify -> rule_format, elimify -> elim_format, ...);
  3299 
  3300 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3301 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3302 should have to change intro!! to intro? only); replaced "delrule" by
  3303 "rule del";
  3304 
  3305 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3306 
  3307 * Provers: strengthened force_tac by using new first_best_tac;
  3308 
  3309 * LaTeX document preparation: several changes of isabelle.sty (see
  3310 lib/texinputs);
  3311 
  3312 
  3313 *** Document preparation ***
  3314 
  3315 * formal comments (text blocks etc.) in new-style theories may now
  3316 contain antiquotations of thm/prop/term/typ/text to be presented
  3317 according to latex print mode; concrete syntax is like this:
  3318 @{term[show_types] "f(x) = a + x"};
  3319 
  3320 * isatool mkdir provides easy setup of Isabelle session directories,
  3321 including proper document sources;
  3322 
  3323 * generated LaTeX sources are now deleted after successful run
  3324 (isatool document -c); may retain a copy somewhere else via -D option
  3325 of isatool usedir;
  3326 
  3327 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3328 style files, achieving self-contained LaTeX sources and simplifying
  3329 LaTeX debugging;
  3330 
  3331 * old-style theories now produce (crude) LaTeX output as well;
  3332 
  3333 * browser info session directories are now self-contained (may be put
  3334 on WWW server seperately); improved graphs of nested sessions; removed
  3335 graph for 'all sessions';
  3336 
  3337 * several improvements in isabelle style files; \isabellestyle{it}
  3338 produces fake math mode output; \isamarkupheader is now \section by
  3339 default; see lib/texinputs/isabelle.sty etc.;
  3340 
  3341 
  3342 *** Isar ***
  3343 
  3344 * Isar/Pure: local results and corresponding term bindings are now
  3345 subject to Hindley-Milner polymorphism (similar to ML); this
  3346 accommodates incremental type-inference very nicely;
  3347 
  3348 * Isar/Pure: new derived language element 'obtain' supports
  3349 generalized existence reasoning;
  3350 
  3351 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3352 support accumulation of results, without applying any rules yet;
  3353 useful to collect intermediate results without explicit name
  3354 references, and for use with transitivity rules with more than 2
  3355 premises;
  3356 
  3357 * Isar/Pure: scalable support for case-analysis type proofs: new
  3358 'case' language element refers to local contexts symbolically, as
  3359 produced by certain proof methods; internally, case names are attached
  3360 to theorems as "tags";
  3361 
  3362 * Isar/Pure: theory command 'hide' removes declarations from
  3363 class/type/const name spaces;
  3364 
  3365 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3366 indicate potential overloading;
  3367 
  3368 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3369 
  3370 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3371 "{a,b,c}" instead of {a,b,c};
  3372 
  3373 * Isar/Pure now provides its own version of intro/elim/dest
  3374 attributes; useful for building new logics, but beware of confusion
  3375 with the version in Provers/classical;
  3376 
  3377 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3378 case name 'antecedent';
  3379 
  3380 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3381 to the current context is now done automatically);
  3382 
  3383 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3384 for definining proof methods in ML;
  3385 
  3386 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3387 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3388 most cases, one should have to change intro!! to intro? only);
  3389 replaced "delrule" by "rule del";
  3390 
  3391 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3392 'symmetric' attribute (the latter supercedes [RS sym]);
  3393 
  3394 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3395 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3396 well (including splits);
  3397 
  3398 * Isar/Provers: Simplifier and Classical methods now support all kind
  3399 of modifiers used in the past, including 'cong', 'iff', etc.
  3400 
  3401 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3402 of Simplifier and Classical reasoner);
  3403 
  3404 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3405 now support named cases; major packages (inductive, datatype, primrec,
  3406 recdef) support case names and properly name parameters;
  3407 
  3408 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3409 monotonicity conditions are extracted to be proven at end of
  3410 calculations;
  3411 
  3412 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3413 method anyway;
  3414 
  3415 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3416 split_if split_if_asm; datatype package provides theorems foo.splits =
  3417 foo.split foo.split_asm for each datatype;
  3418 
  3419 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3420 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3421 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3422 use "(cases (simplified))" method in proper proof texts);
  3423 
  3424 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3425 
  3426 * Isar: names of theorems etc. may be natural numbers as well;
  3427 
  3428 * Isar: 'pr' command: optional arguments for goals_limit and
  3429 ProofContext.prems_limit; no longer prints theory contexts, but only
  3430 proof states;
  3431 
  3432 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3433 additional print modes to be specified; e.g. "pr(latex)" will print
  3434 proof state according to the Isabelle LaTeX style;
  3435 
  3436 * Isar: improved support for emulating tactic scripts, including proof
  3437 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3438 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3439 (for HOL datatypes);
  3440 
  3441 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3442 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3443 'proof method scripts' have to be in depth-first order;
  3444 
  3445 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3446 
  3447 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3448 should instead use individual commands for printing items
  3449 (print_commands, print_methods etc.);
  3450 
  3451 * Isar: added 'nothing' --- the empty list of theorems;
  3452 
  3453 
  3454 *** HOL ***
  3455 
  3456 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3457 corresponding virtual machine and a specification of its bytecode
  3458 verifier and a lightweight bytecode verifier, including proofs of
  3459 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3460 Cornelia Pusch (see also the homepage of project Bali at
  3461 http://isabelle.in.tum.de/Bali/);
  3462 
  3463 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3464 Clemens Ballarin;
  3465 
  3466 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3467 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3468 Rasmussen;
  3469 
  3470 * HOL/Lattice: fundamental concepts of lattice theory and order
  3471 structures, including duals, properties of bounds versus algebraic
  3472 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3473 Theorem for complete lattices etc.; may also serve as a demonstration
  3474 for abstract algebraic reasoning using axiomatic type classes, and
  3475 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3476 
  3477 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3478 von Oheimb;
  3479 
  3480 * HOL/IMPP: extension of IMP with local variables and mutually
  3481 recursive procedures, by David von Oheimb;
  3482 
  3483 * HOL/Lambda: converted into new-style theory and document;
  3484 
  3485 * HOL/ex/Multiquote: example of multiple nested quotations and
  3486 anti-quotations -- basically a generalized version of de-Bruijn
  3487 representation; very useful in avoiding lifting of operations;
  3488 
  3489 * HOL/record: added general record equality rule to simpset; fixed
  3490 select-update simplification procedure to handle extended records as
  3491 well; admit "r" as field name;
  3492 
  3493 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3494 other numeric types and also as the identity of groups, rings, etc.;
  3495 
  3496 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3497 Types nat and int belong to this axclass;
  3498 
  3499 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3500    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3501    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3502   two terms #m*u and #n*u are replaced by #(m+n)*u
  3503     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3504   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3505     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3506 
  3507 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3508 powerful prover for predicate logic but knows nothing of clasets; see
  3509 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3510 
  3511 * HOL: new version of "case_tac" subsumes both boolean case split and
  3512 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3513 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3514 
  3515 * HOL: simplification no longer dives into case-expressions: only the
  3516 selector expression is simplified, but not the remaining arms; to
  3517 enable full simplification of case-expressions for datatype t, you may
  3518 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3519 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3520 
  3521 * HOL/recdef: the recursion equations generated by 'recdef' for
  3522 function 'f' are now called f.simps instead of f.rules; if all
  3523 termination conditions are proved automatically, these simplification
  3524 rules are added to the simpset, as in primrec; rules may be named
  3525 individually as well, resulting in a separate list of theorems for
  3526 each equation;
  3527 
  3528 * HOL/While is a new theory that provides a while-combinator. It
  3529 permits the definition of tail-recursive functions without the
  3530 provision of a termination measure. The latter is necessary once the
  3531 invariant proof rule for while is applied.
  3532 
  3533 * HOL: new (overloaded) notation for the set of elements below/above
  3534 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3535 
  3536 * HOL: theorems impI, allI, ballI bound as "strip";
  3537 
  3538 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3539 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3540 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3541 
  3542 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3543 
  3544 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3545 main HOL, but was unused);
  3546 
  3547 * HOL: fewer consts declared as global (e.g. have to refer to
  3548 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3549 
  3550 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3551 in case of overlap with user translations (e.g. judgements over
  3552 tuples); (note that the underlying logical represenation is still
  3553 bogus);
  3554 
  3555 
  3556 *** ZF ***
  3557 
  3558 * ZF: simplification automatically cancels common terms in arithmetic
  3559 expressions over nat and int;
  3560 
  3561 * ZF: new treatment of nat to minimize type-checking: all operators
  3562 coerce their operands to a natural number using the function natify,
  3563 making the algebraic laws unconditional;
  3564 
  3565 * ZF: as above, for int: operators coerce their operands to an integer
  3566 using the function intify;
  3567 
  3568 * ZF: the integer library now contains many of the usual laws for the
  3569 orderings, including $<=, and monotonicity laws for $+ and $*;
  3570 
  3571 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3572 simplification;
  3573 
  3574 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3575 to the simplifier and classical reasoner simultaneously;
  3576 
  3577 
  3578 *** General ***
  3579 
  3580 * Provers: blast_tac now handles actual object-logic rules as
  3581 assumptions; note that auto_tac uses blast_tac internally as well;
  3582 
  3583 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3584 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3585 
  3586 * Provers: delrules now handles destruct rules as well (no longer need
  3587 explicit make_elim);
  3588 
  3589 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3590   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3591 use instead the strong form,
  3592   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3593 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3594 from destruct-rules;
  3595 
  3596 * Provers: Simplifier.easy_setup provides a fast path to basic
  3597 Simplifier setup for new object-logics;
  3598 
  3599 * Pure: AST translation rules no longer require constant head on LHS;
  3600 
  3601 * Pure: improved name spaces: ambiguous output is qualified; support
  3602 for hiding of names;
  3603 
  3604 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3605 XSYMBOL_HOME; no longer need to do manual configuration in most
  3606 situations;
  3607 
  3608 * system: compression of ML heaps images may now be controlled via -c
  3609 option of isabelle and isatool usedir (currently only observed by
  3610 Poly/ML);
  3611 
  3612 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3613 useful for remote X11);
  3614 
  3615 * system: provide TAGS file for Isabelle sources;
  3616 
  3617 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3618 order;
  3619 
  3620 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3621 timing flag supersedes proof_timing and Toplevel.trace;
  3622 
  3623 * ML: new combinators |>> and |>>> for incremental transformations
  3624 with secondary results (e.g. certain theory extensions):
  3625 
  3626 * ML: PureThy.add_defs gets additional argument to indicate potential
  3627 overloading (usually false);
  3628 
  3629 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3630 results;
  3631 
  3632 
  3633 
  3634 New in Isabelle99 (October 1999)
  3635 --------------------------------
  3636 
  3637 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3638 
  3639 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3640 are no longer simplified.  (This allows the simplifier to unfold recursive
  3641 functional programs.)  To restore the old behaviour, declare
  3642 
  3643     Delcongs [if_weak_cong];
  3644 
  3645 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3646 complement;
  3647 
  3648 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3649 
  3650 * HOL/datatype: mutual_induct_tac no longer exists --
  3651   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3652 
  3653 * HOL/typedef: fixed type inference for representing set; type
  3654 arguments now have to occur explicitly on the rhs as type constraints;
  3655 
  3656 * ZF: The con_defs part of an inductive definition may no longer refer
  3657 to constants declared in the same theory;
  3658 
  3659 * HOL, ZF: the function mk_cases, generated by the inductive
  3660 definition package, has lost an argument.  To simplify its result, it
  3661 uses the default simpset instead of a supplied list of theorems.
  3662 
  3663 * HOL/List: the constructors of type list are now Nil and Cons;
  3664 
  3665 * Simplifier: the type of the infix ML functions
  3666         setSSolver addSSolver setSolver addSolver
  3667 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3668 for packaging solvers. A solver is created via
  3669         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3670 where the string argument is only a comment.
  3671 
  3672 
  3673 *** Proof tools ***
  3674 
  3675 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3676 decision procedure for linear arithmetic. Currently it is used for
  3677 types `nat', `int', and `real' in HOL (see below); it can, should and
  3678 will be instantiated for other types and logics as well.
  3679 
  3680 * The simplifier now accepts rewrite rules with flexible heads, eg
  3681      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3682   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3683   matching.
  3684 
  3685 
  3686 *** General ***
  3687 
  3688 * New Isabelle/Isar subsystem provides an alternative to traditional
  3689 tactical theorem proving; together with the ProofGeneral/isar user
  3690 interface it offers an interactive environment for developing human
  3691 readable proof documents (Isar == Intelligible semi-automated
  3692 reasoning); for further information see isatool doc isar-ref,
  3693 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3694 
  3695 * improved and simplified presentation of theories: better HTML markup
  3696 (including colors), graph views in several sizes; isatool usedir now
  3697 provides a proper interface for user theories (via -P option); actual
  3698 document preparation based on (PDF)LaTeX is available as well (for
  3699 new-style theories only); see isatool doc system for more information;
  3700 
  3701 * native support for Proof General, both for classic Isabelle and
  3702 Isabelle/Isar;
  3703 
  3704 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3705 using the graph browser tool;
  3706 
  3707 * Isabelle manuals now also available as PDF;
  3708 
  3709 * theory loader rewritten from scratch (may not be fully
  3710 bug-compatible); old loadpath variable has been replaced by show_path,
  3711 add_path, del_path, reset_path functions; new operations such as
  3712 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3713 isatool doc ref);
  3714 
  3715 * improved isatool install: option -k creates KDE application icon,
  3716 option -p DIR installs standalone binaries;
  3717 
  3718 * added ML_PLATFORM setting (useful for cross-platform installations);
  3719 more robust handling of platform specific ML images for SML/NJ;
  3720 
  3721 * the settings environment is now statically scoped, i.e. it is never
  3722 created again in sub-processes invoked from isabelle, isatool, or
  3723 Isabelle;
  3724 
  3725 * path element specification '~~' refers to '$ISABELLE_HOME';
  3726 
  3727 * in locales, the "assumes" and "defines" parts may be omitted if
  3728 empty;
  3729 
  3730 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3731 long arrows);
  3732 
  3733 * new print_mode "HTML";
  3734 
  3735 * new flag show_tags controls display of tags of theorems (which are
  3736 basically just comments that may be attached by some tools);
  3737 
  3738 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3739 mode and goal output format:
  3740 
  3741 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3742 244c244
  3743 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3744 ---
  3745 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3746 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3747 181c181
  3748 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3749 ---
  3750 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3751 
  3752 * function bind_thms stores lists of theorems (cf. bind_thm);
  3753 
  3754 * new shorthand tactics ftac, eatac, datac, fatac;
  3755 
  3756 * qed (and friends) now accept "" as result name; in that case the
  3757 theorem is not stored, but proper checks and presentation of the
  3758 result still apply;
  3759 
  3760 * theorem database now also indexes constants "Trueprop", "all",
  3761 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3762 
  3763 
  3764 *** HOL ***
  3765 
  3766 ** HOL arithmetic **
  3767 
  3768 * There are now decision procedures for linear arithmetic over nat and
  3769 int:
  3770 
  3771 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3772 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3773 are treated as atomic; subformulae not involving type `nat' or `int'
  3774 are ignored; quantified subformulae are ignored unless they are
  3775 positive universal or negative existential. The tactic has to be
  3776 invoked by hand and can be a little bit slow. In particular, the
  3777 running time is exponential in the number of occurrences of `min' and
  3778 `max', and `-' on `nat'.
  3779 
  3780 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3781 (negated) (in)equalities among the premises and the conclusion into
  3782 account (i.e. no compound formulae) and does not know about `min' and
  3783 `max', and `-' on `nat'. It is fast and is used automatically by the
  3784 simplifier.
  3785 
  3786 NB: At the moment, these decision procedures do not cope with mixed
  3787 nat/int formulae where the two parts interact, such as `m < n ==>
  3788 int(m) < int(n)'.
  3789 
  3790 * HOL/Numeral provides a generic theory of numerals (encoded
  3791 efficiently as bit strings); setup for types nat/int/real is in place;
  3792 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3793 int, existing theories and proof scripts may require a few additional
  3794 type constraints;
  3795 
  3796 * integer division and remainder can now be performed on constant
  3797 arguments;
  3798 
  3799 * many properties of integer multiplication, division and remainder
  3800 are now available;
  3801 
  3802 * An interface to the Stanford Validity Checker (SVC) is available through the
  3803 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3804 are proved automatically.  SVC must be installed separately, and its results
  3805 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3806 invocation of the underlying oracle).  For SVC see
  3807   http://verify.stanford.edu/SVC
  3808 
  3809 * IsaMakefile: the HOL-Real target now builds an actual image;
  3810 
  3811 
  3812 ** HOL misc **
  3813 
  3814 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3815 (in Isabelle/Isar) -- by Gertrud Bauer;
  3816 
  3817 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3818 analysis for assembly languages with subtypes;
  3819 
  3820 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3821 -- avoids syntactic ambiguities and treats state, transition, and
  3822 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3823 changed syntax and (many) tactics;
  3824 
  3825 * HOL/inductive: Now also handles more general introduction rules such
  3826   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3827   theorems are now maintained within the theory (maintained via the
  3828   "mono" attribute);
  3829 
  3830 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3831   (using function types) such as
  3832 
  3833   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3834 
  3835 * HOL/record: record_simproc (part of the default simpset) takes care
  3836 of selectors applied to updated records; record_split_tac is no longer
  3837 part of the default claset; update_defs may now be removed from the
  3838 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3839 
  3840   claset_ref () := claset() addSWrapper record_split_wrapper;
  3841   Delsimprocs [record_simproc]
  3842 
  3843 * HOL/typedef: fixed type inference for representing set; type
  3844 arguments now have to occur explicitly on the rhs as type constraints;
  3845 
  3846 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3847 names rather than an ML expression;
  3848 
  3849 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3850 supplied later.  Program schemes can be defined, such as
  3851     "While B C s = (if B s then While B C (C s) else s)"
  3852 where the well-founded relation can be chosen after B and C have been given.
  3853 
  3854 * HOL/List: the constructors of type list are now Nil and Cons;
  3855 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3856 course, ML tools referring to List.list.op # etc. have to be adapted;
  3857 
  3858 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3859 disabled by default; run isabelle with option -m HOL to get back to
  3860 the original Gordon/HOL-style output;
  3861 
  3862 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3863 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3864 
  3865 * HOL basic syntax simplified (more orthogonal): all variants of
  3866 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3867 Eps operator is provided as well: "SOME x. P[x]";
  3868 
  3869 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3870 
  3871 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3872 thus available for user theories;
  3873 
  3874 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3875 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3876 time;
  3877 
  3878 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3879 several times and then mp;
  3880 
  3881 
  3882 *** LK ***
  3883 
  3884 * the notation <<...>> is now available as a notation for sequences of
  3885 formulas;
  3886 
  3887 * the simplifier is now installed
  3888 
  3889 * the axiom system has been generalized (thanks to Soren Heilmann)
  3890 
  3891 * the classical reasoner now has a default rule database
  3892 
  3893 
  3894 *** ZF ***
  3895 
  3896 * new primrec section allows primitive recursive functions to be given
  3897 directly (as in HOL) over datatypes and the natural numbers;
  3898 
  3899 * new tactics induct_tac and exhaust_tac for induction (or case
  3900 analysis) over datatypes and the natural numbers;
  3901 
  3902 * the datatype declaration of type T now defines the recursor T_rec;
  3903 
  3904 * simplification automatically does freeness reasoning for datatype
  3905 constructors;
  3906 
  3907 * automatic type-inference, with AddTCs command to insert new
  3908 type-checking rules;
  3909 
  3910 * datatype introduction rules are now added as Safe Introduction rules
  3911 to the claset;
  3912 
  3913 * the syntax "if P then x else y" is now available in addition to
  3914 if(P,x,y);
  3915 
  3916 
  3917 *** Internal programming interfaces ***
  3918 
  3919 * tuned simplifier trace output; new flag debug_simp;
  3920 
  3921 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3922 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3923 
  3924 * AxClass.axclass_tac lost the theory argument;
  3925 
  3926 * tuned current_goals_markers semantics: begin / end goal avoids
  3927 printing empty lines;
  3928 
  3929 * removed prs and prs_fn hook, which was broken because it did not
  3930 include \n in its semantics, forcing writeln to add one
  3931 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3932 string -> unit if you really want to output text without newline;
  3933 
  3934 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3935 plain output, interface builders may have to enable 'isabelle_font'
  3936 mode to get Isabelle font glyphs as before;
  3937 
  3938 * refined token_translation interface; INCOMPATIBILITY: output length
  3939 now of type real instead of int;
  3940 
  3941 * theory loader actions may be traced via new ThyInfo.add_hook
  3942 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3943 your own database of information attached to *whole* theories -- as
  3944 opposed to intra-theory data slots offered via TheoryDataFun;
  3945 
  3946 * proper handling of dangling sort hypotheses (at last!);
  3947 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3948 extra sort hypotheses that can be witnessed from the type signature;
  3949 the force_strip_shyps flag is gone, any remaining shyps are simply
  3950 left in the theorem (with a warning issued by strip_shyps_warning);
  3951 
  3952 
  3953 
  3954 New in Isabelle98-1 (October 1998)
  3955 ----------------------------------
  3956 
  3957 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3958 
  3959 * several changes of automated proof tools;
  3960 
  3961 * HOL: major changes to the inductive and datatype packages, including
  3962 some minor incompatibilities of theory syntax;
  3963 
  3964 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3965 called `inj_on';
  3966 
  3967 * HOL: removed duplicate thms in Arith:
  3968   less_imp_add_less  should be replaced by  trans_less_add1
  3969   le_imp_add_le      should be replaced by  trans_le_add1
  3970 
  3971 * HOL: unary minus is now overloaded (new type constraints may be
  3972 required);
  3973 
  3974 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3975 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3976 now taken as an integer constant.
  3977 
  3978 * Pure: ML function 'theory_of' renamed to 'theory';
  3979 
  3980 
  3981 *** Proof tools ***
  3982 
  3983 * Simplifier:
  3984   1. Asm_full_simp_tac is now more aggressive.
  3985      1. It will sometimes reorient premises if that increases their power to
  3986         simplify.
  3987      2. It does no longer proceed strictly from left to right but may also
  3988         rotate premises to achieve further simplification.
  3989      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3990      old Asm_full_simp_tac in that it does not rotate premises.
  3991   2. The simplifier now knows a little bit about nat-arithmetic.
  3992 
  3993 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3994 allows for selected deletion of wrappers, by introduction of names for
  3995 wrapper functionals.  This implies that addbefore, addSbefore,
  3996 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3997 and that adding two tactics with the same name overwrites the first
  3998 one (emitting a warning).
  3999   type wrapper = (int -> tactic) -> (int -> tactic)
  4000   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4001   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4002   delWrapper, delSWrapper: claset *  string            -> claset
  4003   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4004 
  4005 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4006 semantics; addbefore now affects only the unsafe part of step_tac
  4007 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4008 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4009 by Force_tac;
  4010 
  4011 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4012 compWrapper; added safe wrapper (and access functions for it);
  4013 
  4014 * HOL/split_all_tac is now much faster and fails if there is nothing
  4015 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4016 and the names of the automatically generated variables have changed.
  4017 split_all_tac has moved within claset() from unsafe wrappers to safe
  4018 wrappers, which means that !!-bound variables are split much more
  4019 aggressively, and safe_tac and clarify_tac now split such variables.
  4020 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4021 Note: the same holds for record_split_tac, which does the job of
  4022 split_all_tac for record fields.
  4023 
  4024 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4025 permanently to the default simpset using Addsplits just like
  4026 Addsimps. They can be removed via Delsplits just like
  4027 Delsimps. Lower-case versions are also available.
  4028 
  4029 * HOL/Simplifier: The rule split_if is now part of the default
  4030 simpset. This means that the simplifier will eliminate all occurrences
  4031 of if-then-else in the conclusion of a goal. To prevent this, you can
  4032 either remove split_if completely from the default simpset by
  4033 `Delsplits [split_if]' or remove it in a specific call of the
  4034 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4035 other case splitting rules to/from the default simpset: every datatype
  4036 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4037 t is the name of the datatype).
  4038 
  4039 * Classical reasoner / Simplifier combination: new force_tac (and
  4040 derivatives Force_tac, force) combines rewriting and classical
  4041 reasoning (and whatever other tools) similarly to auto_tac, but is
  4042 aimed to solve the given subgoal completely.
  4043 
  4044 
  4045 *** General ***
  4046 
  4047 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4048 and `goalw': the theory is no longer needed as an explicit argument -
  4049 the current theory context is used; assumptions are no longer returned
  4050 at the ML-level unless one of them starts with ==> or !!; it is
  4051 recommended to convert to these new commands using isatool fixgoal
  4052 (backup your sources first!);
  4053 
  4054 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4055 the current theory context, and 'theory' to lookup stored theories;
  4056 
  4057 * new theory section 'locale' for declaring constants, assumptions and
  4058 definitions that have local scope;
  4059 
  4060 * new theory section 'nonterminals' for purely syntactic types;
  4061 
  4062 * new theory section 'setup' for generic ML setup functions
  4063 (e.g. package initialization);
  4064 
  4065 * the distribution now includes Isabelle icons: see
  4066 lib/logo/isabelle-{small,tiny}.xpm;
  4067 
  4068 * isatool install - install binaries with absolute references to
  4069 ISABELLE_HOME/bin;
  4070 
  4071 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4072 
  4073 * print mode 'emacs' reserved for Isamode;
  4074 
  4075 * support multiple print (ast) translations per constant name;
  4076 
  4077 * theorems involving oracles are now printed with a suffixed [!];
  4078 
  4079 
  4080 *** HOL ***
  4081 
  4082 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4083 
  4084 * HOL/inductive package reorganized and improved: now supports mutual
  4085 definitions such as
  4086 
  4087   inductive EVEN ODD
  4088     intrs
  4089       null "0 : EVEN"
  4090       oddI "n : EVEN ==> Suc n : ODD"
  4091       evenI "n : ODD ==> Suc n : EVEN"
  4092 
  4093 new theorem list "elims" contains an elimination rule for each of the
  4094 recursive sets; inductive definitions now handle disjunctive premises
  4095 correctly (also ZF);
  4096 
  4097 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4098 "mutual_induct" no longer exists - the induction rule is always
  4099 contained in "induct";
  4100 
  4101 
  4102 * HOL/datatype package re-implemented and greatly improved: now
  4103 supports mutually recursive datatypes such as
  4104 
  4105   datatype
  4106     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4107             | SUM ('a aexp) ('a aexp)
  4108             | DIFF ('a aexp) ('a aexp)
  4109             | NUM 'a
  4110   and
  4111     'a bexp = LESS ('a aexp) ('a aexp)
  4112             | AND ('a bexp) ('a bexp)
  4113             | OR ('a bexp) ('a bexp)
  4114 
  4115 as well as indirectly recursive datatypes such as
  4116 
  4117   datatype
  4118     ('a, 'b) term = Var 'a
  4119                   | App 'b ((('a, 'b) term) list)
  4120 
  4121 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4122 induction on mutually / indirectly recursive datatypes.
  4123 
  4124 Primrec equations are now stored in theory and can be accessed via
  4125 <function_name>.simps.
  4126 
  4127 INCOMPATIBILITIES:
  4128 
  4129   - Theories using datatypes must now have theory Datatype as an
  4130     ancestor.
  4131   - The specific <typename>.induct_tac no longer exists - use the
  4132     generic induct_tac instead.
  4133   - natE has been renamed to nat.exhaust - use exhaust_tac
  4134     instead of res_inst_tac ... natE. Note that the variable
  4135     names in nat.exhaust differ from the names in natE, this
  4136     may cause some "fragile" proofs to fail.
  4137   - The theorems split_<typename>_case and split_<typename>_case_asm
  4138     have been renamed to <typename>.split and <typename>.split_asm.
  4139   - Since default sorts of type variables are now handled correctly,
  4140     some datatype definitions may have to be annotated with explicit
  4141     sort constraints.
  4142   - Primrec definitions no longer require function name and type
  4143     of recursive argument.
  4144 
  4145 Consider using isatool fixdatatype to adapt your theories and proof
  4146 scripts to the new package (backup your sources first!).
  4147 
  4148 
  4149 * HOL/record package: considerably improved implementation; now
  4150 includes concrete syntax for record types, terms, updates; theorems
  4151 for surjective pairing and splitting !!-bound record variables; proof
  4152 support is as follows:
  4153 
  4154   1) standard conversions (selectors or updates applied to record
  4155 constructor terms) are part of the standard simpset;
  4156 
  4157   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4158 made part of standard simpset and claset via addIffs;
  4159 
  4160   3) a tactic for record field splitting (record_split_tac) is part of
  4161 the standard claset (addSWrapper);
  4162 
  4163 To get a better idea about these rules you may retrieve them via
  4164 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4165 the name of your record type.
  4166 
  4167 The split tactic 3) conceptually simplifies by the following rule:
  4168 
  4169   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4170 
  4171 Thus any record variable that is bound by meta-all will automatically
  4172 blow up into some record constructor term, consequently the
  4173 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4174 solve record problems automatically.
  4175 
  4176 
  4177 * reorganized the main HOL image: HOL/Integ and String loaded by
  4178 default; theory Main includes everything;
  4179 
  4180 * automatic simplification of integer sums and comparisons, using cancellation;
  4181 
  4182 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4183 
  4184 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4185 
  4186 * many new identities for unions, intersections, set difference, etc.;
  4187 
  4188 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4189 called split_if, split_split, split_sum_case and split_nat_case (to go
  4190 with add/delsplits);
  4191 
  4192 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4193 (?x::unit) = (); this is made part of the default simpset, which COULD
  4194 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4195 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4196 unit_abs_eta_conv is added in order to counter the effect of
  4197 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4198 %u.f();
  4199 
  4200 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4201 makes more sense);
  4202 
  4203 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4204   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4205   disjointness reasoning but breaking a few old proofs.
  4206 
  4207 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4208 to 'converse' from 'inverse' (for compatibility with ZF and some
  4209 literature);
  4210 
  4211 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4212 the well-founded relation;
  4213 
  4214 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4215     Compl A.  The "Compl" syntax remains available as input syntax for this
  4216     release ONLY.
  4217 
  4218 * HOL/Update: new theory of function updates:
  4219     f(a:=b) == %x. if x=a then b else f x
  4220 may also be iterated as in f(a:=b,c:=d,...);
  4221 
  4222 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4223 
  4224 * HOL/List:
  4225   - new function list_update written xs[i:=v] that updates the i-th
  4226     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4227   - new function `upt' written [i..j(] which generates the list
  4228     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4229     bound write [i..j], which is a shorthand for [i..j+1(].
  4230   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4231 
  4232 * HOL/Arith:
  4233   - removed 'pred' (predecessor) function;
  4234   - generalized some theorems about n-1;
  4235   - many new laws about "div" and "mod";
  4236   - new laws about greatest common divisors (see theory ex/Primes);
  4237 
  4238 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4239 instead of "inverse";
  4240 
  4241 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4242   of the multiset ordering;
  4243 
  4244 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4245   (not included by default);
  4246 
  4247 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4248 
  4249 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4250   programs, i.e. different program variables may have different types.
  4251 
  4252 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4253   [previously, this check worked only if the rewrite rule was unconditional]
  4254   Now rew can involve either definitions or equalities (either == or =).
  4255 
  4256 
  4257 *** ZF ***
  4258 
  4259 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4260   only the theorems proved on ZF.ML;
  4261 
  4262 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4263   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4264   disjointness reasoning but breaking a few old proofs.
  4265 
  4266 * ZF/Update: new theory of function updates
  4267     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4268   may also be iterated as in f(a:=b,c:=d,...);
  4269 
  4270 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4271 
  4272 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4273   [previously, this check worked only if the rewrite rule was unconditional]
  4274   Now rew can involve either definitions or equalities (either == or =).
  4275 
  4276 * case_tac provided for compatibility with HOL
  4277     (like the old excluded_middle_tac, but with subgoals swapped)
  4278 
  4279 
  4280 *** Internal programming interfaces ***
  4281 
  4282 * Pure: several new basic modules made available for general use, see
  4283 also src/Pure/README;
  4284 
  4285 * improved the theory data mechanism to support encapsulation (data
  4286 kind name replaced by private Object.kind, acting as authorization
  4287 key); new type-safe user interface via functor TheoryDataFun; generic
  4288 print_data function becomes basically useless;
  4289 
  4290 * removed global_names compatibility flag -- all theory declarations
  4291 are qualified by default;
  4292 
  4293 * module Pure/Syntax now offers quote / antiquote translation
  4294 functions (useful for Hoare logic etc. with implicit dependencies);
  4295 see HOL/ex/Antiquote for an example use;
  4296 
  4297 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4298 cterm -> thm;
  4299 
  4300 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4301 subgoal;
  4302 
  4303 * Display.print_goals function moved to Locale.print_goals;
  4304 
  4305 * standard print function for goals supports current_goals_markers
  4306 variable for marking begin of proof, end of proof, start of goal; the
  4307 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4308 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4309 for example;
  4310 
  4311 
  4312 
  4313 New in Isabelle98 (January 1998)
  4314 --------------------------------
  4315 
  4316 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4317 
  4318 * changed lexical syntax of terms / types: dots made part of long
  4319 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4320 
  4321 * simpset (and claset) reference variable replaced by functions
  4322 simpset / simpset_ref;
  4323 
  4324 * no longer supports theory aliases (via merge) and non-trivial
  4325 implicit merge of thms' signatures;
  4326 
  4327 * most internal names of constants changed due to qualified names;
  4328 
  4329 * changed Pure/Sequence interface (see Pure/seq.ML);
  4330 
  4331 
  4332 *** General Changes ***
  4333 
  4334 * hierachically structured name spaces (for consts, types, axms, thms
  4335 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4336 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4337 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4338 long_names for fully qualified output names; NOTE: ML programs
  4339 (special tactics, packages etc.) referring to internal names may have
  4340 to be adapted to cope with fully qualified names; in case of severe
  4341 backward campatibility problems try setting 'global_names' at compile
  4342 time to have enrything declared within a flat name space; one may also
  4343 fine tune name declarations in theories via the 'global' and 'local'
  4344 section;
  4345 
  4346 * reimplemented the implicit simpset and claset using the new anytype
  4347 data filed in signatures; references simpset:simpset ref etc. are
  4348 replaced by functions simpset:unit->simpset and
  4349 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4350 to patch your ML files accordingly;
  4351 
  4352 * HTML output now includes theory graph data for display with Java
  4353 applet or isatool browser; data generated automatically via isatool
  4354 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4355 
  4356 * defs may now be conditional; improved rewrite_goals_tac to handle
  4357 conditional equations;
  4358 
  4359 * defs now admits additional type arguments, using TYPE('a) syntax;
  4360 
  4361 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4362 creates a new theory node; implicit merge of thms' signatures is
  4363 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4364 transfer:theory->thm->thm in (rare) cases;
  4365 
  4366 * improved handling of draft signatures / theories; draft thms (and
  4367 ctyps, cterms) are automatically promoted to real ones;
  4368 
  4369 * slightly changed interfaces for oracles: admit many per theory, named
  4370 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4371 
  4372 * print_goals: optional output of const types (set show_consts and
  4373 show_types);
  4374 
  4375 * improved output of warnings (###) and errors (***);
  4376 
  4377 * subgoal_tac displays a warning if the new subgoal has type variables;
  4378 
  4379 * removed old README and Makefiles;
  4380 
  4381 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4382 
  4383 * removed obsolete init_pps and init_database;
  4384 
  4385 * deleted the obsolete tactical STATE, which was declared by
  4386     fun STATE tacfun st = tacfun st st;
  4387 
  4388 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4389 (which abbreviates $HOME);
  4390 
  4391 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4392 use isatool fixseq to adapt your ML programs (this works for fully
  4393 qualified references to the Sequence structure only!);
  4394 
  4395 * use_thy no longer requires writable current directory; it always
  4396 reloads .ML *and* .thy file, if either one is out of date;
  4397 
  4398 
  4399 *** Classical Reasoner ***
  4400 
  4401 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4402 tactics that use classical reasoning to simplify a subgoal without
  4403 splitting it into several subgoals;
  4404 
  4405 * Safe_tac: like safe_tac but uses the default claset;
  4406 
  4407 
  4408 *** Simplifier ***
  4409 
  4410 * added simplification meta rules:
  4411     (asm_)(full_)simplify: simpset -> thm -> thm;
  4412 
  4413 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4414 logics (again);
  4415 
  4416 * added prems argument to simplification procedures;
  4417 
  4418 * HOL, FOL, ZF: added infix function `addsplits':
  4419   instead of `<simpset> setloop (split_tac <thms>)'
  4420   you can simply write `<simpset> addsplits <thms>'
  4421 
  4422 
  4423 *** Syntax ***
  4424 
  4425 * TYPE('a) syntax for type reflection terms;
  4426 
  4427 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4428 
  4429 * pretty printer: changed order of mixfix annotation preference (again!);
  4430 
  4431 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4432 
  4433 
  4434 *** HOL ***
  4435 
  4436 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4437   with `addloop' of the simplifier to faciliate case splitting in premises.
  4438 
  4439 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4440 
  4441 * HOL/Auth: new protocol proofs including some for the Internet
  4442   protocol TLS;
  4443 
  4444 * HOL/Map: new theory of `maps' a la VDM;
  4445 
  4446 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4447 cancelling out common nat summands from =, <, <= (in)equalities, or
  4448 differences; simplification procedures nat_cancel_factor for
  4449 cancelling common factor from =, <, <= (in)equalities over natural
  4450 sums; nat_cancel contains both kinds of procedures, it is installed by
  4451 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4452 
  4453 * HOL/simplifier: terms of the form
  4454   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4455   are rewritten to
  4456   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4457   and those of the form
  4458   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4459   are rewritten to
  4460   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4461 
  4462 * HOL/datatype
  4463   Each datatype `t' now comes with a theorem `split_t_case' 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 
  4471   and a theorem `split_t_case_asm' of the form
  4472 
  4473   P(t_case f1 ... fn x) =
  4474     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4475         ...
  4476        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4477      )
  4478   which can be added to a simpset via `addsplits'. The existing theorems
  4479   expand_list_case and expand_option_case have been renamed to
  4480   split_list_case and split_option_case.
  4481 
  4482 * HOL/Arithmetic:
  4483   - `pred n' is automatically converted to `n-1'.
  4484     Users are strongly encouraged not to use `pred' any longer,
  4485     because it will disappear altogether at some point.
  4486   - Users are strongly encouraged to write "0 < n" rather than
  4487     "n ~= 0". Theorems and proof tools have been modified towards this
  4488     `standard'.
  4489 
  4490 * HOL/Lists:
  4491   the function "set_of_list" has been renamed "set" (and its theorems too);
  4492   the function "nth" now takes its arguments in the reverse order and
  4493   has acquired the infix notation "!" as in "xs!n".
  4494 
  4495 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4496 
  4497 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4498   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4499 
  4500 * HOL/record: extensible records with schematic structural subtyping
  4501 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4502 still lacks various theorems and concrete record syntax;
  4503 
  4504 
  4505 *** HOLCF ***
  4506 
  4507 * removed "axioms" and "generated by" sections;
  4508 
  4509 * replaced "ops" section by extended "consts" section, which is capable of
  4510   handling the continuous function space "->" directly;
  4511 
  4512 * domain package:
  4513   . proves theorems immediately and stores them in the theory,
  4514   . creates hierachical name space,
  4515   . now uses normal mixfix annotations (instead of cinfix...),
  4516   . minor changes to some names and values (for consistency),
  4517   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4518   . separator between mutual domain defs: changed "," to "and",
  4519   . improved handling of sort constraints;  now they have to
  4520     appear on the left-hand side of the equations only;
  4521 
  4522 * fixed LAM <x,y,zs>.b syntax;
  4523 
  4524 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4525 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4526 
  4527 
  4528 *** FOL and ZF ***
  4529 
  4530 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4531   with `addloop' of the simplifier to faciliate case splitting in premises.
  4532 
  4533 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4534 in HOL, they strip ALL and --> from proved theorems;
  4535 
  4536 
  4537 
  4538 New in Isabelle94-8 (May 1997)
  4539 ------------------------------
  4540 
  4541 *** General Changes ***
  4542 
  4543 * new utilities to build / run / maintain Isabelle etc. (in parts
  4544 still somewhat experimental); old Makefiles etc. still functional;
  4545 
  4546 * new 'Isabelle System Manual';
  4547 
  4548 * INSTALL text, together with ./configure and ./build scripts;
  4549 
  4550 * reimplemented type inference for greater efficiency, better error
  4551 messages and clean internal interface;
  4552 
  4553 * prlim command for dealing with lots of subgoals (an easier way of
  4554 setting goals_limit);
  4555 
  4556 
  4557 *** Syntax ***
  4558 
  4559 * supports alternative (named) syntax tables (parser and pretty
  4560 printer); internal interface is provided by add_modesyntax(_i);
  4561 
  4562 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4563 be used in conjunction with the Isabelle symbol font; uses the
  4564 "symbols" syntax table;
  4565 
  4566 * added token_translation interface (may translate name tokens in
  4567 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4568 the current print_mode); IMPORTANT: user print translation functions
  4569 are responsible for marking newly introduced bounds
  4570 (Syntax.mark_boundT);
  4571 
  4572 * token translations for modes "xterm" and "xterm_color" that display
  4573 names in bold, underline etc. or colors (which requires a color
  4574 version of xterm);
  4575 
  4576 * infixes may now be declared with names independent of their syntax;
  4577 
  4578 * added typed_print_translation (like print_translation, but may
  4579 access type of constant);
  4580 
  4581 
  4582 *** Classical Reasoner ***
  4583 
  4584 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4585 some limitations.  Blast_tac...
  4586   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4587   + ignores elimination rules that don't have the correct format
  4588         (the conclusion MUST be a formula variable)
  4589   + ignores types, which can make HOL proofs fail
  4590   + rules must not require higher-order unification, e.g. apply_type in ZF
  4591     [message "Function Var's argument not a bound variable" relates to this]
  4592   + its proof strategy is more general but can actually be slower
  4593 
  4594 * substitution with equality assumptions no longer permutes other
  4595 assumptions;
  4596 
  4597 * minor changes in semantics of addafter (now called addaltern); renamed
  4598 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4599 (and access functions for it);
  4600 
  4601 * improved combination of classical reasoner and simplifier:
  4602   + functions for handling clasimpsets
  4603   + improvement of addss: now the simplifier is called _after_ the
  4604     safe steps.
  4605   + safe variant of addss called addSss: uses safe simplifications
  4606     _during_ the safe steps. It is more complete as it allows multiple
  4607     instantiations of unknowns (e.g. with slow_tac).
  4608 
  4609 *** Simplifier ***
  4610 
  4611 * added interface for simplification procedures (functions that
  4612 produce *proven* rewrite rules on the fly, depending on current
  4613 redex);
  4614 
  4615 * ordering on terms as parameter (used for ordered rewriting);
  4616 
  4617 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4618 
  4619 * the solver is now split into a safe and an unsafe part.
  4620 This should be invisible for the normal user, except that the
  4621 functions setsolver and addsolver have been renamed to setSolver and
  4622 addSolver; added safe_asm_full_simp_tac;
  4623 
  4624 
  4625 *** HOL ***
  4626 
  4627 * a generic induction tactic `induct_tac' which works for all datatypes and
  4628 also for type `nat';
  4629 
  4630 * a generic case distinction tactic `exhaust_tac' which works for all
  4631 datatypes and also for type `nat';
  4632 
  4633 * each datatype comes with a function `size';
  4634 
  4635 * patterns in case expressions allow tuple patterns as arguments to
  4636 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4637 
  4638 * primrec now also works with type nat;
  4639 
  4640 * recdef: a new declaration form, allows general recursive functions to be
  4641 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4642 
  4643 * the constant for negation has been renamed from "not" to "Not" to
  4644 harmonize with FOL, ZF, LK, etc.;
  4645 
  4646 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4647 infinite lists;
  4648 
  4649 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4650 
  4651 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4652 problems in commutative rings, using axiomatic type classes for + and *;
  4653 
  4654 * more examples in HOL/MiniML and HOL/Auth;
  4655 
  4656 * more default rewrite rules for quantifiers, union/intersection;
  4657 
  4658 * a new constant `arbitrary == @x.False';
  4659 
  4660 * HOLCF/IOA replaces old HOL/IOA;
  4661 
  4662 * HOLCF changes: derived all rules and arities
  4663   + axiomatic type classes instead of classes
  4664   + typedef instead of faking type definitions
  4665   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4666   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4667   + eliminated the types void, one, tr
  4668   + use unit lift and bool lift (with translations) instead of one and tr
  4669   + eliminated blift from Lift3.thy (use Def instead of blift)
  4670   all eliminated rules are derived as theorems --> no visible changes ;
  4671 
  4672 
  4673 *** ZF ***
  4674 
  4675 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4676 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4677 as ZF_cs addSIs [equalityI];
  4678 
  4679 
  4680 
  4681 New in Isabelle94-7 (November 96)
  4682 ---------------------------------
  4683 
  4684 * allowing negative levels (as offsets) in prlev and choplev;
  4685 
  4686 * super-linear speedup for large simplifications;
  4687 
  4688 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4689 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4690 FAIL); can suppress it using the command Delsimps (ex_simps @
  4691 all_simps); De Morgan laws are also now included, by default;
  4692 
  4693 * improved printing of ==>  :  ~:
  4694 
  4695 * new object-logic "Sequents" adds linear logic, while replacing LK
  4696 and Modal (thanks to Sara Kalvala);
  4697 
  4698 * HOL/Auth: correctness proofs for authentication protocols;
  4699 
  4700 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4701 examples on HOL/Auth);
  4702 
  4703 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4704 the rewriter and classical reasoner simultaneously;
  4705 
  4706 * function uresult no longer returns theorems in "standard" format;
  4707 regain previous version by: val uresult = standard o uresult;
  4708 
  4709 
  4710 
  4711 New in Isabelle94-6
  4712 -------------------
  4713 
  4714 * oracles -- these establish an interface between Isabelle and trusted
  4715 external reasoners, which may deliver results as theorems;
  4716 
  4717 * proof objects (in particular record all uses of oracles);
  4718 
  4719 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4720 
  4721 * "constdefs" section in theory files;
  4722 
  4723 * "primrec" section (HOL) no longer requires names;
  4724 
  4725 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4726 
  4727 
  4728 
  4729 New in Isabelle94-5
  4730 -------------------
  4731 
  4732 * reduced space requirements;
  4733 
  4734 * automatic HTML generation from theories;
  4735 
  4736 * theory files no longer require "..." (quotes) around most types;
  4737 
  4738 * new examples, including two proofs of the Church-Rosser theorem;
  4739 
  4740 * non-curried (1994) version of HOL is no longer distributed;
  4741 
  4742 
  4743 
  4744 New in Isabelle94-4
  4745 -------------------
  4746 
  4747 * greatly reduced space requirements;
  4748 
  4749 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4750 
  4751 * searchable theorem database (see the section "Retrieving theorems" on
  4752 page 8 of the Reference Manual);
  4753 
  4754 * new examples, including Grabczewski's monumental case study of the
  4755 Axiom of Choice;
  4756 
  4757 * The previous version of HOL renamed to Old_HOL;
  4758 
  4759 * The new version of HOL (previously called CHOL) uses a curried syntax
  4760 for functions.  Application looks like f a b instead of f(a,b);
  4761 
  4762 * Mutually recursive inductive definitions finally work in HOL;
  4763 
  4764 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4765 translates to the operator "split";
  4766 
  4767 
  4768 
  4769 New in Isabelle94-3
  4770 -------------------
  4771 
  4772 * new infix operator, addss, allowing the classical reasoner to
  4773 perform simplification at each step of its search.  Example:
  4774         fast_tac (cs addss ss)
  4775 
  4776 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4777 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4778 look like (a,b) instead of <a,b>;
  4779 
  4780 * PLEASE NOTE: CHOL will eventually replace HOL!
  4781 
  4782 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4783 It translates to the operator "split".  A new theory of integers is available;
  4784 
  4785 * In ZF, integer numerals now denote two's-complement binary integers.
  4786 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4787 
  4788 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4789 of the Axiom of Choice;
  4790 
  4791 
  4792 
  4793 New in Isabelle94-2
  4794 -------------------
  4795 
  4796 * Significantly faster resolution;
  4797 
  4798 * the different sections in a .thy file can now be mixed and repeated
  4799 freely;
  4800 
  4801 * Database of theorems for FOL, HOL and ZF.  New
  4802 commands including qed, qed_goal and bind_thm store theorems in the database.
  4803 
  4804 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4805 a given theory (thms_of), or find out what theory a theorem was proved in
  4806 (theory_of_thm);
  4807 
  4808 * Bugs fixed in the inductive definition and datatype packages;
  4809 
  4810 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4811 and HOL_dup_cs obsolete;
  4812 
  4813 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4814 have been removed;
  4815 
  4816 * Simpler definition of function space in ZF;
  4817 
  4818 * new results about cardinal and ordinal arithmetic in ZF;
  4819 
  4820 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4821 types;
  4822 
  4823 
  4824 $Id$