NEWS
author wenzelm
Thu Jun 14 00:48:42 2007 +0200 (2007-06-14)
changeset 23379 d0e3f790bd73
parent 23377 197b6a39592c
child 23449 dd874e6a3282
permissions -rw-r--r--
updated 'find_theorems' -- moved ProofGeneral specifics to ProofGeneral/CHANGES;
     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 * IntDef: The constant "int :: nat => int" has been removed; now
   545   "int" is an abbreviation for "of_nat :: nat => int". Potential
   546   INCOMPATIBILITY due to differences in default simp rules:
   547   - "int (Suc m)" simplifies to "int m + 1" instead of "1 + int m"
   548   - "int (m * n)" simplifies to "int m * int n"
   549 
   550 * Method "algebra" solves polynomial equations over (semi)rings using
   551   Groebner bases. The (semi)ring structure is defined by locales and
   552   the tool setup depends on that generic context. Installing the
   553   method for a specific type involves instantiating the locale and
   554   possibly adding declarations for computation on the coefficients.
   555   The method is already instantiated for natural numbers and for the
   556   axiomatic class of idoms with numerals.  See also the paper by
   557   Chaieb and Wenzel at CALCULEMUS 2007 for the general principles
   558   underlying this architecture of context-aware proof-tools.
   559 
   560 * constant "List.op @" now named "List.append".  Use ML antiquotations
   561 @{const_name List.append} or @{term " ... @ ... "} to circumvent
   562 possible incompatibilities when working on ML level.
   563 
   564 * Constant renames due to introduction of canonical name prefixing for
   565   class package:
   566 
   567     HOL.abs ~> HOL.minus_class.abs
   568     HOL.divide ~> HOL.divide_class.divide
   569     Nat.power ~> Nat.power_class.power
   570     Nat.size ~> Nat.size_class.size
   571     Numeral.number_of ~> Numeral.number_class.number_of
   572     FixedPoint.Inf ~> FixedPoint.complete_lattice_class.Inf
   573 
   574 * Rudimentary class target mechanism involves constant renames:
   575 
   576     Orderings.min ~> Orderings.ord_class.min
   577     Orderings.max ~> Orderings.ord_class.max
   578     FixedPoint.Sup ~> FixedPoint.complete_lattice_class.Sup
   579 
   580 * case expressions and primrec: missing cases now mapped to "undefined"
   581 instead of "arbitrary"
   582 
   583 * new constant "undefined" with axiom "undefined x = undefined"
   584 
   585 * new class "default" with associated constant "default"
   586 
   587 * new function listsum :: 'a list => 'a for arbitrary monoids.
   588   Special syntax: "SUM x <- xs. f x" (and latex variants)
   589 
   590 * new (input only) syntax for Haskell-like list comprehension, eg
   591   [(x,y). x <- xs, y <- ys, x ~= y]
   592   For details see List.thy.
   593 
   594 * The special syntax for function "filter" has changed from [x : xs. P] to
   595   [x <- xs. P] to avoid an ambiguity caused by list comprehension syntax,
   596   and for uniformity. INCOMPATIBILITY
   597 
   598 * Library/Pretty_Int.thy: maps HOL numerals on target language integer literals
   599     when generating code.
   600 
   601 * Library/Pretty_Char.thy: maps HOL characters on target language character literals
   602     when generating code.
   603 
   604 * Library/Commutative_Ring.thy: switched from recdef to function package;
   605     constants add, mul, pow now curried.  Infix syntax for algebraic operations.
   606 
   607 * Some steps towards more uniform lattice theory development in HOL.
   608 
   609     constants "meet" and "join" now named "inf" and "sup"
   610     constant "Meet" now named "Inf"
   611 
   612     classes "meet_semilorder" and "join_semilorder" now named
   613       "lower_semilattice" and "upper_semilattice"
   614     class "lorder" now named "lattice"
   615     class "comp_lat" now named "complete_lattice"
   616 
   617     Instantiation of lattice classes allows explicit definitions
   618     for "inf" and "sup" operations.
   619 
   620   INCOMPATIBILITY.  Theorem renames:
   621 
   622     meet_left_le            ~> inf_le1
   623     meet_right_le           ~> inf_le2
   624     join_left_le            ~> sup_ge1
   625     join_right_le           ~> sup_ge2
   626     meet_join_le            ~> inf_sup_ord
   627     le_meetI                ~> le_infI
   628     join_leI                ~> le_supI
   629     le_meet                 ~> le_inf_iff
   630     le_join                 ~> ge_sup_conv
   631     meet_idempotent         ~> inf_idem
   632     join_idempotent         ~> sup_idem
   633     meet_comm               ~> inf_commute
   634     join_comm               ~> sup_commute
   635     meet_leI1               ~> le_infI1
   636     meet_leI2               ~> le_infI2
   637     le_joinI1               ~> le_supI1
   638     le_joinI2               ~> le_supI2
   639     meet_assoc              ~> inf_assoc
   640     join_assoc              ~> sup_assoc
   641     meet_left_comm          ~> inf_left_commute
   642     meet_left_idempotent    ~> inf_left_idem
   643     join_left_comm          ~> sup_left_commute
   644     join_left_idempotent    ~> sup_left_idem
   645     meet_aci                ~> inf_aci
   646     join_aci                ~> sup_aci
   647     le_def_meet             ~> le_iff_inf
   648     le_def_join             ~> le_iff_sup
   649     join_absorp2            ~> sup_absorb2
   650     join_absorp1            ~> sup_absorb1
   651     meet_absorp1            ~> inf_absorb1
   652     meet_absorp2            ~> inf_absorb2
   653     meet_join_absorp        ~> inf_sup_absorb
   654     join_meet_absorp        ~> sup_inf_absorb
   655     distrib_join_le         ~> distrib_sup_le
   656     distrib_meet_le         ~> distrib_inf_le
   657 
   658     add_meet_distrib_left   ~> add_inf_distrib_left
   659     add_join_distrib_left   ~> add_sup_distrib_left
   660     is_join_neg_meet        ~> is_join_neg_inf
   661     is_meet_neg_join        ~> is_meet_neg_sup
   662     add_meet_distrib_right  ~> add_inf_distrib_right
   663     add_join_distrib_right  ~> add_sup_distrib_right
   664     add_meet_join_distribs  ~> add_sup_inf_distribs
   665     join_eq_neg_meet        ~> sup_eq_neg_inf
   666     meet_eq_neg_join        ~> inf_eq_neg_sup
   667     add_eq_meet_join        ~> add_eq_inf_sup
   668     meet_0_imp_0            ~> inf_0_imp_0
   669     join_0_imp_0            ~> sup_0_imp_0
   670     meet_0_eq_0             ~> inf_0_eq_0
   671     join_0_eq_0             ~> sup_0_eq_0
   672     neg_meet_eq_join        ~> neg_inf_eq_sup
   673     neg_join_eq_meet        ~> neg_sup_eq_inf
   674     join_eq_if              ~> sup_eq_if
   675 
   676     mono_meet               ~> mono_inf
   677     mono_join               ~> mono_sup
   678     meet_bool_eq            ~> inf_bool_eq
   679     join_bool_eq            ~> sup_bool_eq
   680     meet_fun_eq             ~> inf_fun_eq
   681     join_fun_eq             ~> sup_fun_eq
   682     meet_set_eq             ~> inf_set_eq
   683     join_set_eq             ~> sup_set_eq
   684     meet1_iff               ~> inf1_iff
   685     meet2_iff               ~> inf2_iff
   686     meet1I                  ~> inf1I
   687     meet2I                  ~> inf2I
   688     meet1D1                 ~> inf1D1
   689     meet2D1                 ~> inf2D1
   690     meet1D2                 ~> inf1D2
   691     meet2D2                 ~> inf2D2
   692     meet1E                  ~> inf1E
   693     meet2E                  ~> inf2E
   694     join1_iff               ~> sup1_iff
   695     join2_iff               ~> sup2_iff
   696     join1I1                 ~> sup1I1
   697     join2I1                 ~> sup2I1
   698     join1I1                 ~> sup1I1
   699     join2I2                 ~> sup1I2
   700     join1CI                 ~> sup1CI
   701     join2CI                 ~> sup2CI
   702     join1E                  ~> sup1E
   703     join2E                  ~> sup2E
   704 
   705     is_meet_Meet            ~> is_meet_Inf
   706     Meet_bool_def           ~> Inf_bool_def
   707     Meet_fun_def            ~> Inf_fun_def
   708     Meet_greatest           ~> Inf_greatest
   709     Meet_lower              ~> Inf_lower
   710     Meet_set_def            ~> Inf_set_def
   711 
   712     listsp_meetI            ~> listsp_infI
   713     listsp_meet_eq          ~> listsp_inf_eq
   714 
   715     meet_min                ~> inf_min
   716     join_max                ~> sup_max
   717 
   718 * Classes "order" and "linorder": facts "refl", "trans" and
   719 "cases" renamed ro "order_refl", "order_trans" and "linorder_cases", to
   720 avoid clashes with HOL "refl" and "trans". INCOMPATIBILITY.
   721 
   722 * Classes "order" and "linorder": 
   723 potential INCOMPATIBILITY: order of proof goals in order/linorder instance
   724 proofs changed.
   725 
   726 * Dropped lemma duplicate def_imp_eq in favor of meta_eq_to_obj_eq.
   727 INCOMPATIBILITY.
   728 
   729 * Dropped lemma duplicate if_def2 in favor of if_bool_eq_conj.
   730 INCOMPATIBILITY.
   731 
   732 * Added syntactic class "size"; overloaded constant "size" now has
   733 type "'a::size ==> bool"
   734 
   735 * Renamed constants "Divides.op div", "Divides.op mod" and "Divides.op
   736 dvd" to "Divides.div_class.div", "Divides.div_class.mod" and "Divides.dvd". INCOMPATIBILITY.
   737 
   738 * Added method "lexicographic_order" automatically synthesizes
   739 termination relations as lexicographic combinations of size measures
   740 -- 'function' package.
   741 
   742 * HOL/records: generalised field-update to take a function on the
   743 field rather than the new value: r(|A := x|) is translated to A_update
   744 (K x) r The K-combinator that is internally used is called K_record.
   745 INCOMPATIBILITY: Usage of the plain update functions has to be
   746 adapted.
   747  
   748 * axclass "semiring_0" now contains annihilation axioms x * 0 = 0 and
   749 0 * x = 0, which are required for a semiring.  Richer structures do
   750 not inherit from semiring_0 anymore, because this property is a
   751 theorem there, not an axiom.  INCOMPATIBILITY: In instances of
   752 semiring_0, there is more to prove, but this is mostly trivial.
   753 
   754 * axclass "recpower" was generalized to arbitrary monoids, not just
   755 commutative semirings.  INCOMPATIBILITY: If you use recpower and need
   756 commutativity or a semiring property, add the corresponding classes.
   757 
   758 * Unified locale partial_order with class definition (cf. theory
   759 Orderings), added parameter ``less''.  INCOMPATIBILITY.
   760 
   761 * Constant "List.list_all2" in List.thy now uses authentic syntax.
   762 INCOMPATIBILITY: translations containing list_all2 may go wrong.  On
   763 Isar level, use abbreviations instead.
   764 
   765 * Renamed constant "List.op mem" to "List.memberl" INCOMPATIBILITY:
   766 rarely occuring name references (e.g. ``List.op mem.simps'') require
   767 renaming (e.g. ``List.memberl.simps'').
   768 
   769 * Renamed constants "0" to "HOL.zero_class.zero" and "1" to "HOL.one_class.one".
   770 INCOMPATIBILITY.
   771 
   772 * Added class "HOL.eq", allowing for code generation with polymorphic equality.
   773 
   774 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
   775 been abandoned in favour of plain 'int'. INCOMPATIBILITY --
   776 significant changes for setting up numeral syntax for types:
   777 
   778   - new constants Numeral.pred and Numeral.succ instead
   779       of former Numeral.bin_pred and Numeral.bin_succ.
   780   - Use integer operations instead of bin_add, bin_mult and so on.
   781   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
   782   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
   783 
   784 See HOL/Integ/IntArith.thy for an example setup.
   785 
   786 * New top level command 'normal_form' computes the normal form of a
   787 term that may contain free variables. For example ``normal_form
   788 "rev[a,b,c]"'' produces ``[b,c,a]'' (without proof).  This command is
   789 suitable for heavy-duty computations because the functions are
   790 compiled to ML first.
   791 
   792 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   793 25 like -->); output depends on the "iff" print_mode, the default is
   794 "A = B" (with priority 50).
   795 
   796 * Renamed constants in HOL.thy and Orderings.thy:
   797     op +   ~> HOL.plus_class.plus
   798     op -   ~> HOL.minus_class.minus
   799     uminus ~> HOL.minus_class.uminus
   800     op *   ~> HOL.times_class.times
   801     op <   ~> Orderings.ord_class.less
   802     op <=  ~> Orderings.ord_class.less_eq
   803 
   804 Adaptions may be required in the following cases:
   805 
   806 a) User-defined constants using any of the names "plus", "minus", "times",
   807 "less" or "less_eq". The standard syntax translations for "+", "-" and "*"
   808 may go wrong.
   809 INCOMPATIBILITY: use more specific names.
   810 
   811 b) Variables named "plus", "minus", "times", "less", "less_eq"
   812 INCOMPATIBILITY: use more specific names.
   813 
   814 c) Permutative equations (e.g. "a + b = b + a")
   815 Since the change of names also changes the order of terms, permutative
   816 rewrite rules may get applied in a different order. Experience shows that
   817 this is rarely the case (only two adaptions in the whole Isabelle
   818 distribution).
   819 INCOMPATIBILITY: rewrite proofs
   820 
   821 d) ML code directly refering to constant names
   822 This in general only affects hand-written proof tactics, simprocs and so on.
   823 INCOMPATIBILITY: grep your sourcecode and replace names.  Consider use
   824 of const_name ML antiquotations.
   825 
   826 * Relations less (<) and less_eq (<=) are also available on type bool.
   827 Modified syntax to disallow nesting without explicit parentheses,
   828 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".
   829 
   830 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   831 
   832 * Relation composition operator "op O" now has precedence 75 and binds
   833 stronger than union and intersection. INCOMPATIBILITY.
   834 
   835 * The old set interval syntax "{m..n(}" (and relatives) has been
   836 removed.  Use "{m..<n}" (and relatives) instead.
   837 
   838 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   839 "t = s" to False (by simproc "neq_simproc").  For backward
   840 compatibility this can be disabled by ML "reset use_neq_simproc".
   841 
   842 * "m dvd n" where m and n are numbers is evaluated to True/False by
   843 simp.
   844 
   845 * Theorem Cons_eq_map_conv no longer declared as ``simp''.
   846 
   847 * Theorem setsum_mult renamed to setsum_right_distrib.
   848 
   849 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   850 ``rule'' method.
   851 
   852 * Reimplemented methods ``sat'' and ``satx'', with several
   853 improvements: goals no longer need to be stated as "<prems> ==>
   854 False", equivalences (i.e. "=" on type bool) are handled, variable
   855 names of the form "lit_<n>" are no longer reserved, significant
   856 speedup.
   857 
   858 * Methods ``sat'' and ``satx'' can now replay MiniSat proof traces.
   859 zChaff is still supported as well.
   860 
   861 * 'inductive' and 'datatype': provide projections of mutual rules,
   862 bundled as foo_bar.inducts;
   863 
   864 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
   865 Library.
   866 
   867 * Library: moved theory Accessible_Part to main HOL.
   868 
   869 * Library: added theory Coinductive_List of potentially infinite lists
   870 as greatest fixed-point.
   871 
   872 * Library: added theory AssocList which implements (finite) maps as
   873 association lists.
   874 
   875 * Added proof method ``evaluation'' for efficiently solving a goal
   876 (i.e. a boolean expression) by compiling it to ML. The goal is
   877 "proved" (via an oracle) if it evaluates to True.
   878 
   879 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
   880 also when invoked by the simplifier.  This results in the simplifier
   881 being more powerful on arithmetic goals.  INCOMPATIBILITY.  Set
   882 fast_arith_split_limit to 0 to obtain the old behavior.
   883 
   884 * Support for hex (0x20) and binary (0b1001) numerals.
   885 
   886 * New method: reify eqs (t), where eqs are equations for an
   887 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
   888 parameter, computes a term s::'b and a list xs::'a list and proves the
   889 theorem I xs s = t. This is also known as reification or quoting. The
   890 resulting theorem is applied to the subgoal to substitute t with I xs
   891 s.  If t is omitted, the subgoal itself is reified.
   892 
   893 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
   894 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
   895 where f is supposed to be a computable function (in the sense of code
   896 generattion). The method uses reify to compute s and xs as above then
   897 applies corr_thm and uses normalization by evaluation to "prove" f s =
   898 r and finally gets the theorem t = r, which is again applied to the
   899 subgoal. An Example is available in HOL/ex/ReflectionEx.thy.
   900 
   901 * Reflection: Automatic refification now handels binding, an example
   902 is available in HOL/ex/ReflectionEx.thy
   903 
   904 
   905 *** HOL-Algebra ***
   906 
   907 * Formalisation of ideals and the quotient construction over rings.
   908 
   909 * Order and lattice theory no longer based on records.
   910 INCOMPATIBILITY.
   911 
   912 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
   913 greatest_closed.  INCOMPATIBILITY.
   914 
   915 * Method algebra is now set up via an attribute.  For examples see
   916 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
   917 of algebraic structures.
   918 
   919 * Renamed theory CRing to Ring.
   920 
   921 
   922 *** HOL-Complex ***
   923 
   924 * Theory Real: new method ferrack implements quantifier elimination
   925 for linear arithmetic over the reals. The quantifier elimination
   926 feature is used only for decision, for compatibility with arith. This
   927 means a goal is either solved or left unchanged, no simplification.
   928 
   929 * Hyperreal: Functions root and sqrt are now defined on negative real
   930 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
   931 Nonnegativity side conditions have been removed from many lemmas, so
   932 that more subgoals may now be solved by simplification; potential
   933 INCOMPATIBILITY.
   934 
   935 * Real: New axiomatic classes formalize real normed vector spaces and
   936 algebras, using new overloaded constants scaleR :: real => 'a => 'a
   937 and norm :: 'a => real.
   938 
   939 * Real: New constant of_real :: real => 'a::real_algebra_1 injects
   940 from reals into other types. The overloaded constant Reals :: 'a set
   941 is now defined as range of_real; potential INCOMPATIBILITY.
   942 
   943 * Real: ML code generation is supported now and hence also quickcheck.
   944 Reals are implemented as arbitrary precision rationals.
   945 
   946 * Hyperreal: Several constants that previously worked only for the
   947 reals have been generalized, so they now work over arbitrary vector
   948 spaces. Type annotations may need to be added in some cases; potential
   949 INCOMPATIBILITY.
   950 
   951   Infinitesimal  :: ('a::real_normed_vector) star set
   952   HFinite        :: ('a::real_normed_vector) star set
   953   HInfinite      :: ('a::real_normed_vector) star set
   954   approx         :: ('a::real_normed_vector) star => 'a star => bool
   955   monad          :: ('a::real_normed_vector) star => 'a star set
   956   galaxy         :: ('a::real_normed_vector) star => 'a star set
   957   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
   958   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
   959   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
   960   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
   961   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
   962   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
   963   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
   964   sgn            :: 'a::real_normed_vector => 'a
   965   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
   966 
   967 * Complex: Some complex-specific constants are now abbreviations for
   968 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
   969 hnorm.  Other constants have been entirely removed in favor of the
   970 polymorphic versions (INCOMPATIBILITY):
   971 
   972   approx        <-- capprox
   973   HFinite       <-- CFinite
   974   HInfinite     <-- CInfinite
   975   Infinitesimal <-- CInfinitesimal
   976   monad         <-- cmonad
   977   galaxy        <-- cgalaxy
   978   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
   979   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
   980   (ns)deriv     <-- (ns)cderiv
   981 
   982 
   983 *** ML ***
   984 
   985 * Generic arithmetic modules: Tools/integer.ML, Tools/rat.ML, Tools/float.ML
   986 
   987 * Context data interfaces (Theory/Proof/GenericDataFun): removed
   988 name/print, uninitialized data defaults to ad-hoc copy of empty value,
   989 init only required for impure data.  INCOMPATIBILITY: empty really
   990 need to be empty (no dependencies on theory content!)
   991 
   992 * ML within Isar: antiquotations allow to embed statically-checked
   993 formal entities in the source, referring to the context available at
   994 compile-time.  For example:
   995 
   996 ML {* @{typ "'a => 'b"} *}
   997 ML {* @{term "%x. x"} *}
   998 ML {* @{prop "x == y"} *}
   999 ML {* @{ctyp "'a => 'b"} *}
  1000 ML {* @{cterm "%x. x"} *}
  1001 ML {* @{cprop "x == y"} *}
  1002 ML {* @{thm asm_rl} *}
  1003 ML {* @{thms asm_rl} *}
  1004 ML {* @{const_name c} *}
  1005 ML {* @{const_syntax c} *}
  1006 ML {* @{context} *}
  1007 ML {* @{theory} *}
  1008 ML {* @{theory Pure} *}
  1009 ML {* @{simpset} *}
  1010 ML {* @{claset} *}
  1011 ML {* @{clasimpset} *}
  1012 
  1013 The same works for sources being ``used'' within an Isar context.
  1014 
  1015 * ML in Isar: improved error reporting; extra verbosity with
  1016 Toplevel.debug enabled.
  1017 
  1018 * Pure/library:
  1019 
  1020   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
  1021   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
  1022 
  1023 The semantics of "burrow" is: "take a function with *simulatanously*
  1024 transforms a list of value, and apply it *simulatanously* to a list of
  1025 list of values of the appropriate type". Compare this with "map" which
  1026 would *not* apply its argument function simulatanously but in
  1027 sequence; "fold_burrow" has an additional context.
  1028 
  1029 * Pure/library: functions map2 and fold2 with curried syntax for
  1030 simultanous mapping and folding:
  1031 
  1032     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
  1033     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
  1034 
  1035 * Pure/library: indexed lists - some functions in the Isabelle library
  1036 treating lists over 'a as finite mappings from [0...n] to 'a have been
  1037 given more convenient names and signatures reminiscent of similar
  1038 functions for alists, tables, etc:
  1039 
  1040   val nth: 'a list -> int -> 'a 
  1041   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
  1042   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
  1043 
  1044 Note that fold_index starts counting at index 0, not 1 like foldln
  1045 used to.
  1046 
  1047 * Pure/library: added general ``divide_and_conquer'' combinator on
  1048 lists.
  1049 
  1050 * Pure/General/table.ML: the join operations now works via exceptions
  1051 DUP/SAME instead of type option.  This is simpler in simple cases, and
  1052 admits slightly more efficient complex applications.
  1053 
  1054 * Pure: datatype Context.generic joins theory/Proof.context and
  1055 provides some facilities for code that works in either kind of
  1056 context, notably GenericDataFun for uniform theory and proof data.
  1057 
  1058 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1059 use Context.generic instead of just theory.
  1060 
  1061 * Pure: simplified internal attribute type, which is now always
  1062 Context.generic * thm -> Context.generic * thm.  Global (theory)
  1063 vs. local (Proof.context) attributes have been discontinued, while
  1064 minimizing code duplication.  Thm.rule_attribute and
  1065 Thm.declaration_attribute build canonical attributes; see also
  1066 structure Context for further operations on Context.generic, notably
  1067 GenericDataFun.  INCOMPATIBILITY, need to adapt attribute type
  1068 declarations and definitions.
  1069 
  1070 * Pure/kernel: consts certification ignores sort constraints given in
  1071 signature declarations.  (This information is not relevant to the
  1072 logic, but only for type inference.)  IMPORTANT INTERNAL CHANGE,
  1073 potential INCOMPATIBILITY.
  1074 
  1075 * Pure: axiomatic type classes are now purely definitional, with
  1076 explicit proofs of class axioms and super class relations performed
  1077 internally.  See Pure/axclass.ML for the main internal interfaces --
  1078 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1079 AxClass.axiomatize_class/classrel/arity supercede
  1080 Sign.add_classes/classrel/arities.
  1081 
  1082 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1083 global/local versions on theory vs. Proof.context have been
  1084 discontinued; Attrib.syntax and Method.syntax have been adapted
  1085 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1086 attributes, methods, etc.
  1087 
  1088 * Pure: several functions of signature "... -> theory -> theory * ..."
  1089 have been reoriented to "... -> theory -> ... * theory" in order to
  1090 allow natural usage in combination with the ||>, ||>>, |-> and
  1091 fold_map combinators.
  1092 
  1093 * Pure: official theorem names (closed derivations) and additional
  1094 comments (tags) are now strictly separate.  Name hints -- which are
  1095 maintained as tags -- may be attached any time without affecting the
  1096 derivation.
  1097 
  1098 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1099 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1100 achieve the old behaviour.
  1101 
  1102 * Pure: the "Goal" constant is now called "prop", supporting a
  1103 slightly more general idea of ``protecting'' meta-level rule
  1104 statements.
  1105 
  1106 * Pure: Logic.(un)varify only works in a global context, which is now
  1107 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1108 Logic.legacy_(un)varify as temporary workaround.
  1109 
  1110 * Pure: structure Name provides scalable operations for generating
  1111 internal variable names, notably Name.variants etc.  This replaces
  1112 some popular functions from term.ML:
  1113 
  1114   Term.variant		->  Name.variant
  1115   Term.variantlist	->  Name.variant_list  (*canonical argument order*)
  1116   Term.invent_names	->  Name.invent_list
  1117 
  1118 Note that low-level renaming rarely occurs in new code -- operations
  1119 from structure Variable are used instead (see below).
  1120 
  1121 * Pure: structure Variable provides fundamental operations for proper
  1122 treatment of fixed/schematic variables in a context.  For example,
  1123 Variable.import introduces fixes for schematics of given facts and
  1124 Variable.export reverses the effect (up to renaming) -- this replaces
  1125 various freeze_thaw operations.
  1126 
  1127 * Pure: structure Goal provides simple interfaces for
  1128 init/conclude/finish and tactical prove operations (replacing former
  1129 Tactic.prove).  Goal.prove is the canonical way to prove results
  1130 within a given context; Goal.prove_global is a degraded version for
  1131 theory level goals, including a global Drule.standard.  Note that
  1132 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1133 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1134 in a locale context).
  1135 
  1136 * Isar: simplified treatment of user-level errors, using exception
  1137 ERROR of string uniformly.  Function error now merely raises ERROR,
  1138 without any side effect on output channels.  The Isar toplevel takes
  1139 care of proper display of ERROR exceptions.  ML code may use plain
  1140 handle/can/try; cat_error may be used to concatenate errors like this:
  1141 
  1142   ... handle ERROR msg => cat_error msg "..."
  1143 
  1144 Toplevel ML code (run directly or through the Isar toplevel) may be
  1145 embedded into the Isar toplevel with exception display/debug like
  1146 this:
  1147 
  1148   Isar.toplevel (fn () => ...)
  1149 
  1150 INCOMPATIBILITY, removed special transform_error facilities, removed
  1151 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1152 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1153 -- use plain ERROR instead.
  1154 
  1155 * Isar: theory setup now has type (theory -> theory), instead of a
  1156 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1157 
  1158 * Isar: installed ML toplevel pretty printer for type Proof.context,
  1159 subject to ProofContext.debug/verbose flags.
  1160 
  1161 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1162 theory before entering a proof state.  Transactions now always see a
  1163 quasi-functional intermediate checkpoint, both in interactive and
  1164 batch mode.
  1165 
  1166 * Simplifier: the simpset of a running simplification process now
  1167 contains a proof context (cf. Simplifier.the_context), which is the
  1168 very context that the initial simpset has been retrieved from (by
  1169 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1170 (solver, looper etc.) may depend on arbitrary proof data.
  1171 
  1172 * Simplifier.inherit_context inherits the proof context (plus the
  1173 local bounds) of the current simplification process; any simproc
  1174 etc. that calls the Simplifier recursively should do this!  Removed
  1175 former Simplifier.inherit_bounds, which is already included here --
  1176 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1177 specify an explicit context using Simplifier.context/theory_context.
  1178 
  1179 * Simplifier/Classical Reasoner: more abstract interfaces
  1180 change_simpset/claset for modifying the simpset/claset reference of a
  1181 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1182 INCOMPATIBILITY.
  1183 
  1184 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1185 "Trueprop" etc.
  1186 
  1187 
  1188 *** System ***
  1189 
  1190 * settings: ML_IDENTIFIER -- which is appended to user specific heap
  1191 locations -- now includes the Isabelle version identifier as well.
  1192 This simplifies use of multiple Isabelle installations.
  1193 
  1194 * isabelle-process: option -S (secure mode) disables some critical
  1195 operations, notably runtime compilation and evaluation of ML source
  1196 code.
  1197 
  1198 
  1199 New in Isabelle2005 (October 2005)
  1200 ----------------------------------
  1201 
  1202 *** General ***
  1203 
  1204 * Theory headers: the new header syntax for Isar theories is
  1205 
  1206   theory <name>
  1207   imports <theory1> ... <theoryN>
  1208   uses <file1> ... <fileM>
  1209   begin
  1210 
  1211 where the 'uses' part is optional.  The previous syntax
  1212 
  1213   theory <name> = <theory1> + ... + <theoryN>:
  1214 
  1215 will disappear in the next release.  Use isatool fixheaders to convert
  1216 existing theory files.  Note that there is no change in ancient
  1217 non-Isar theories now, but these will disappear soon.
  1218 
  1219 * Theory loader: parent theories can now also be referred to via
  1220 relative and absolute paths.
  1221 
  1222 * Command 'find_theorems' searches for a list of criteria instead of a
  1223 list of constants. Known criteria are: intro, elim, dest, name:string,
  1224 simp:term, and any term. Criteria can be preceded by '-' to select
  1225 theorems that do not match. Intro, elim, dest select theorems that
  1226 match the current goal, name:s selects theorems whose fully qualified
  1227 name contain s, and simp:term selects all simplification rules whose
  1228 lhs match term.  Any other term is interpreted as pattern and selects
  1229 all theorems matching the pattern. Available in ProofGeneral under
  1230 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1231 
  1232   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1233 
  1234 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1235 matching the current goal as introduction rule and not having "HOL."
  1236 in their name (i.e. not being defined in theory HOL).
  1237 
  1238 * Command 'thms_containing' has been discontinued in favour of
  1239 'find_theorems'; INCOMPATIBILITY.
  1240 
  1241 * Communication with Proof General is now 8bit clean, which means that
  1242 Unicode text in UTF-8 encoding may be used within theory texts (both
  1243 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1244 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1245 
  1246   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1247   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1248 
  1249 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1250 Classical Reasoner.  Typical big applications run around 2 times
  1251 faster.
  1252 
  1253 
  1254 *** Document preparation ***
  1255 
  1256 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1257 of raw sources.  Only those symbols that do not require additional
  1258 LaTeX packages (depending on comments in isabellesym.sty) are
  1259 displayed properly, everything else is left verbatim.  isatool display
  1260 and isatool print are used as front ends (these are subject to the
  1261 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1262 
  1263 * Command tags control specific markup of certain regions of text,
  1264 notably folding and hiding.  Predefined tags include "theory" (for
  1265 theory begin and end), "proof" for proof commands, and "ML" for
  1266 commands involving ML code; the additional tags "visible" and
  1267 "invisible" are unused by default.  Users may give explicit tag
  1268 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1269 interpretation of tags is determined by the LaTeX job during document
  1270 preparation: see option -V of isatool usedir, or options -n and -t of
  1271 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1272 \isadroptag.
  1273 
  1274 Several document versions may be produced at the same time via isatool
  1275 usedir (the generated index.html will link all of them).  Typical
  1276 specifications include ''-V document=theory,proof,ML'' to present
  1277 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1278 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1279 these parts without any formal replacement text.  The Isabelle site
  1280 default settings produce ''document'' and ''outline'' versions as
  1281 specified above.
  1282 
  1283 * Several new antiquotations:
  1284 
  1285   @{term_type term} prints a term with its type annotated;
  1286 
  1287   @{typeof term} prints the type of a term;
  1288 
  1289   @{const const} is the same as @{term const}, but checks that the
  1290   argument is a known logical constant;
  1291 
  1292   @{term_style style term} and @{thm_style style thm} print a term or
  1293   theorem applying a "style" to it
  1294 
  1295   @{ML text}
  1296 
  1297 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1298 definitions, equations, inequations etc., 'concl' printing only the
  1299 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1300 to print the specified premise.  TermStyle.add_style provides an ML
  1301 interface for introducing further styles.  See also the "LaTeX Sugar"
  1302 document practical applications.  The ML antiquotation prints
  1303 type-checked ML expressions verbatim.
  1304 
  1305 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1306 and 'text' support optional locale specification '(in loc)', which
  1307 specifies the default context for interpreting antiquotations.  For
  1308 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1309 
  1310 * Option 'locale=NAME' of antiquotations specifies an alternative
  1311 context interpreting the subsequent argument.  For example: @{thm
  1312 [locale=lattice] inf_assoc}.
  1313 
  1314 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1315 a proof context.
  1316 
  1317 * Proper output of antiquotations for theory commands involving a
  1318 proof context (such as 'locale' or 'theorem (in loc) ...').
  1319 
  1320 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1321 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1322 
  1323 * isatool usedir: new option -C (default true) controls whether option
  1324 -D should include a copy of the original document directory; -C false
  1325 prevents unwanted effects such as copying of administrative CVS data.
  1326 
  1327 
  1328 *** Pure ***
  1329 
  1330 * Considerably improved version of 'constdefs' command.  Now performs
  1331 automatic type-inference of declared constants; additional support for
  1332 local structure declarations (cf. locales and HOL records), see also
  1333 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1334 sequential dependencies of definitions within a single 'constdefs'
  1335 section; moreover, the declared name needs to be an identifier.  If
  1336 all fails, consider to fall back on 'consts' and 'defs' separately.
  1337 
  1338 * Improved indexed syntax and implicit structures.  First of all,
  1339 indexed syntax provides a notational device for subscripted
  1340 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1341 expressions.  Secondly, in a local context with structure
  1342 declarations, number indexes \<^sub>n or the empty index (default
  1343 number 1) refer to a certain fixed variable implicitly; option
  1344 show_structs controls printing of implicit structures.  Typical
  1345 applications of these concepts involve record types and locales.
  1346 
  1347 * New command 'no_syntax' removes grammar declarations (and
  1348 translations) resulting from the given syntax specification, which is
  1349 interpreted in the same manner as for the 'syntax' command.
  1350 
  1351 * 'Advanced' translation functions (parse_translation etc.) may depend
  1352 on the signature of the theory context being presently used for
  1353 parsing/printing, see also isar-ref manual.
  1354 
  1355 * Improved 'oracle' command provides a type-safe interface to turn an
  1356 ML expression of type theory -> T -> term into a primitive rule of
  1357 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1358 is already included here); see also FOL/ex/IffExample.thy;
  1359 INCOMPATIBILITY.
  1360 
  1361 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1362 before); "cI" is no longer bound, use "c.intro" instead.
  1363 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1364 axclasses vs. locales.
  1365 
  1366 * Improved internal renaming of symbolic identifiers -- attach primes
  1367 instead of base 26 numbers.
  1368 
  1369 * New flag show_question_marks controls printing of leading question
  1370 marks in schematic variable names.
  1371 
  1372 * In schematic variable names, *any* symbol following \<^isub> or
  1373 \<^isup> is now treated as part of the base name.  For example, the
  1374 following works without printing of awkward ".0" indexes:
  1375 
  1376   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1377     by simp
  1378 
  1379 * Inner syntax includes (*(*nested*) comments*).
  1380 
  1381 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1382 annotations as "(00...)".
  1383 
  1384 * Clear separation of logical types and nonterminals, where the latter
  1385 may only occur in 'syntax' specifications or type abbreviations.
  1386 Before that distinction was only partially implemented via type class
  1387 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1388 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1389 exotic syntax specifications may require further adaption
  1390 (e.g. Cube/Cube.thy).
  1391 
  1392 * Removed obsolete type class "logic", use the top sort {} instead.
  1393 Note that non-logical types should be declared as 'nonterminals'
  1394 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1395 specifications.
  1396 
  1397 * Attributes 'induct' and 'cases': type or set names may now be
  1398 locally fixed variables as well.
  1399 
  1400 * Simplifier: can now control the depth to which conditional rewriting
  1401 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1402 Limit.
  1403 
  1404 * Simplifier: simplification procedures may now take the current
  1405 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1406 interface), which is very useful for calling the Simplifier
  1407 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1408 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1409 low-level mk_simproc no longer applies Logic.varify internally, to
  1410 allow for use in a context of fixed variables.
  1411 
  1412 * thin_tac now works even if the assumption being deleted contains !!
  1413 or ==>.  More generally, erule now works even if the major premise of
  1414 the elimination rule contains !! or ==>.
  1415 
  1416 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1417 
  1418 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1419 from Pure, which contains all common declarations already.  Both
  1420 theories are defined via plain Isabelle/Isar .thy files.
  1421 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1422 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1423 use isatool fixcpure to adapt your theory and ML sources.
  1424 
  1425 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1426 selections of theorems in named facts via index ranges.
  1427 
  1428 * 'print_theorems': in theory mode, really print the difference
  1429 wrt. the last state (works for interactive theory development only),
  1430 in proof mode print all local facts (cf. 'print_facts');
  1431 
  1432 * 'hide': option '(open)' hides only base names.
  1433 
  1434 * More efficient treatment of intermediate checkpoints in interactive
  1435 theory development.
  1436 
  1437 * Code generator is now invoked via code_module (incremental code
  1438 generation) and code_library (modular code generation, ML structures
  1439 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1440 must be quoted when used as identifiers.
  1441 
  1442 * New 'value' command for reading, evaluating and printing terms using
  1443 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1444 quoted when used as identifier.
  1445 
  1446 
  1447 *** Locales ***
  1448 
  1449 * New commands for the interpretation of locale expressions in
  1450 theories (1), locales (2) and proof contexts (3).  These generate
  1451 proof obligations from the expression specification.  After the
  1452 obligations have been discharged, theorems of the expression are added
  1453 to the theory, target locale or proof context.  The synopsis of the
  1454 commands is a follows:
  1455 
  1456   (1) interpretation expr inst
  1457   (2) interpretation target < expr
  1458   (3) interpret expr inst
  1459 
  1460 Interpretation in theories and proof contexts require a parameter
  1461 instantiation of terms from the current context.  This is applied to
  1462 specifications and theorems of the interpreted expression.
  1463 Interpretation in locales only permits parameter renaming through the
  1464 locale expression.  Interpretation is smart in that interpretations
  1465 that are active already do not occur in proof obligations, neither are
  1466 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1467 inspect active interpretations of a particular locale.  For details,
  1468 see the Isar Reference manual.  Examples can be found in
  1469 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1470 
  1471 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1472 'interpret' instead.
  1473 
  1474 * New context element 'constrains' for adding type constraints to
  1475 parameters.
  1476 
  1477 * Context expressions: renaming of parameters with syntax
  1478 redeclaration.
  1479 
  1480 * Locale declaration: 'includes' disallowed.
  1481 
  1482 * Proper static binding of attribute syntax -- i.e. types / terms /
  1483 facts mentioned as arguments are always those of the locale definition
  1484 context, independently of the context of later invocations.  Moreover,
  1485 locale operations (renaming and type / term instantiation) are applied
  1486 to attribute arguments as expected.
  1487 
  1488 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1489 actual attributes; rare situations may require Attrib.attribute to
  1490 embed those attributes into Attrib.src that lack concrete syntax.
  1491 Attribute implementations need to cooperate properly with the static
  1492 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1493 Attrib.XXX_thm etc. already do the right thing without further
  1494 intervention.  Only unusual applications -- such as "where" or "of"
  1495 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1496 on the context and the facts involved -- may have to assign parsed
  1497 values to argument tokens explicitly.
  1498 
  1499 * Changed parameter management in theorem generation for long goal
  1500 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1501 theorem statement in rare situations.
  1502 
  1503 * Locale inspection command 'print_locale' omits notes elements.  Use
  1504 'print_locale!' to have them included in the output.
  1505 
  1506 
  1507 *** Provers ***
  1508 
  1509 * Provers/hypsubst.ML: improved version of the subst method, for
  1510 single-step rewriting: it now works in bound variable contexts. New is
  1511 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1512 rewrite a different subterm than the original subst method, which is
  1513 still available as 'simplesubst'.
  1514 
  1515 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1516 and quasi orders.
  1517 
  1518 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1519 reflexive-transitive closure of relations.
  1520 
  1521 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1522 limit (previously hard-coded with a value of 20) user-definable.
  1523 
  1524 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1525 is peformed already.  Object-logics merely need to finish their
  1526 initial simpset configuration as before.  INCOMPATIBILITY.
  1527 
  1528 
  1529 *** HOL ***
  1530 
  1531 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1532 
  1533   syntax (epsilon)
  1534     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1535 
  1536 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1537 and x-symbol; use option '-m epsilon' to get it actually printed.
  1538 Moreover, the mathematically important symbolic identifier \<epsilon>
  1539 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1540 
  1541 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1542 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1543 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1544 support corresponding Isar calculations.
  1545 
  1546 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1547 instead of ":".
  1548 
  1549 * theory SetInterval: changed the syntax for open intervals:
  1550 
  1551   Old       New
  1552   {..n(}    {..<n}
  1553   {)n..}    {n<..}
  1554   {m..n(}   {m..<n}
  1555   {)m..n}   {m<..n}
  1556   {)m..n(}  {m<..<n}
  1557 
  1558 The old syntax is still supported but will disappear in the next
  1559 release.  For conversion use the following Emacs search and replace
  1560 patterns (these are not perfect but work quite well):
  1561 
  1562   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1563   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1564 
  1565 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1566 equalities in commutative rings; method 'algebra' provides a generic
  1567 interface.
  1568 
  1569 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1570 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1571 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1572 be a tuple pattern.
  1573 
  1574 Some new syntax forms are available:
  1575 
  1576   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1577   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1578   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1579   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1580 
  1581 The latter form "\<Sum>x < k. e" used to be based on a separate
  1582 function "Summation", which has been discontinued.
  1583 
  1584 * theory Finite_Set: in structured induction proofs, the insert case
  1585 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1586 (insert F x)'.
  1587 
  1588 * The 'refute' command has been extended to support a much larger
  1589 fragment of HOL, including axiomatic type classes, constdefs and
  1590 typedefs, inductive datatypes and recursion.
  1591 
  1592 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1593 Requires zChaff with proof generation to be installed.  See
  1594 HOL/ex/SAT_Examples.thy for examples.
  1595 
  1596 * Datatype induction via method 'induct' now preserves the name of the
  1597 induction variable. For example, when proving P(xs::'a list) by
  1598 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1599 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1600 in unstructured proof scripts.
  1601 
  1602 * Reworked implementation of records.  Improved scalability for
  1603 records with many fields, avoiding performance problems for type
  1604 inference. Records are no longer composed of nested field types, but
  1605 of nested extension types. Therefore the record type only grows linear
  1606 in the number of extensions and not in the number of fields.  The
  1607 top-level (users) view on records is preserved.  Potential
  1608 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1609 old record representation. The type generated for a record is called
  1610 <record_name>_ext_type.
  1611 
  1612 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1613 proofs triggered by a record definition or a simproc (if
  1614 quick_and_dirty is enabled).  Definitions of large records can take
  1615 quite long.
  1616 
  1617 New simproc record_upd_simproc for simplification of multiple record
  1618 updates enabled by default.  Moreover, trivial updates are also
  1619 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1620 occasionally, since simplification is more powerful by default.
  1621 
  1622 * typedef: proper support for polymorphic sets, which contain extra
  1623 type-variables in the term.
  1624 
  1625 * Simplifier: automatically reasons about transitivity chains
  1626 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1627 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1628 old proofs break occasionally as simplification may now solve more
  1629 goals than previously.
  1630 
  1631 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1632 present.  Works for all partial orders (class "order"), in particular
  1633 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1634 just like y <= x.
  1635 
  1636 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1637 bound variable or a constant then the let is unfolded.  Otherwise
  1638 first a is simplified to b, and then f b is simplified to g. If
  1639 possible we abstract b from g arriving at "let x = b in h x",
  1640 otherwise we unfold the let and arrive at g.  The simproc can be
  1641 enabled/disabled by the reference use_let_simproc.  Potential
  1642 INCOMPATIBILITY since simplification is more powerful by default.
  1643 
  1644 * Classical reasoning: the meson method now accepts theorems as arguments.
  1645 
  1646 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1647 jobs to provide advice on the provability of subgoals.
  1648 
  1649 * Theory OrderedGroup and Ring_and_Field: various additions and
  1650 improvements to faciliate calculations involving equalities and
  1651 inequalities.
  1652 
  1653 The following theorems have been eliminated or modified
  1654 (INCOMPATIBILITY):
  1655 
  1656   abs_eq             now named abs_of_nonneg
  1657   abs_of_ge_0        now named abs_of_nonneg
  1658   abs_minus_eq       now named abs_of_nonpos
  1659   imp_abs_id         now named abs_of_nonneg
  1660   imp_abs_neg_id     now named abs_of_nonpos
  1661   mult_pos           now named mult_pos_pos
  1662   mult_pos_le        now named mult_nonneg_nonneg
  1663   mult_pos_neg_le    now named mult_nonneg_nonpos
  1664   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  1665   mult_neg           now named mult_neg_neg
  1666   mult_neg_le        now named mult_nonpos_nonpos
  1667 
  1668 * Theory Parity: added rules for simplifying exponents.
  1669 
  1670 * Theory List:
  1671 
  1672 The following theorems have been eliminated or modified
  1673 (INCOMPATIBILITY):
  1674 
  1675   list_all_Nil       now named list_all.simps(1)
  1676   list_all_Cons      now named list_all.simps(2)
  1677   list_all_conv      now named list_all_iff
  1678   set_mem_eq         now named mem_iff
  1679 
  1680 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  1681 asymptotic "big O" calculations.  See the notes in BigO.thy.
  1682 
  1683 
  1684 *** HOL-Complex ***
  1685 
  1686 * Theory RealDef: better support for embedding natural numbers and
  1687 integers in the reals.
  1688 
  1689 The following theorems have been eliminated or modified
  1690 (INCOMPATIBILITY):
  1691 
  1692   exp_ge_add_one_self  now requires no hypotheses
  1693   real_of_int_add      reversed direction of equality (use [symmetric])
  1694   real_of_int_minus    reversed direction of equality (use [symmetric])
  1695   real_of_int_diff     reversed direction of equality (use [symmetric])
  1696   real_of_int_mult     reversed direction of equality (use [symmetric])
  1697 
  1698 * Theory RComplete: expanded support for floor and ceiling functions.
  1699 
  1700 * Theory Ln is new, with properties of the natural logarithm
  1701 
  1702 * Hyperreal: There is a new type constructor "star" for making
  1703 nonstandard types.  The old type names are now type synonyms:
  1704 
  1705   hypreal = real star
  1706   hypnat = nat star
  1707   hcomplex = complex star
  1708 
  1709 * Hyperreal: Many groups of similarly-defined constants have been
  1710 replaced by polymorphic versions (INCOMPATIBILITY):
  1711 
  1712   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  1713 
  1714   starset      <-- starsetNat, starsetC
  1715   *s*          <-- *sNat*, *sc*
  1716   starset_n    <-- starsetNat_n, starsetC_n
  1717   *sn*         <-- *sNatn*, *scn*
  1718   InternalSets <-- InternalNatSets, InternalCSets
  1719 
  1720   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  1721   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  1722   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  1723   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  1724   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  1725 
  1726 * Hyperreal: Many type-specific theorems have been removed in favor of
  1727 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  1728 
  1729   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  1730   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  1731   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  1732   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  1733   right_minus <-- hypreal_add_minus
  1734   left_minus <-- {hypreal,hcomplex}_add_minus_left
  1735   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  1736   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  1737   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  1738   mult_1_right <-- hcomplex_mult_one_right
  1739   mult_zero_left <-- hcomplex_mult_zero_left
  1740   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  1741   right_distrib <-- hypnat_add_mult_distrib2
  1742   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  1743   right_inverse <-- hypreal_mult_inverse
  1744   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  1745   order_refl <-- {hypreal,hypnat}_le_refl
  1746   order_trans <-- {hypreal,hypnat}_le_trans
  1747   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  1748   order_less_le <-- {hypreal,hypnat}_less_le
  1749   linorder_linear <-- {hypreal,hypnat}_le_linear
  1750   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  1751   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  1752   add_nonneg_nonneg <-- hypreal_le_add_order
  1753 
  1754 * Hyperreal: Separate theorems having to do with type-specific
  1755 versions of constants have been merged into theorems that apply to the
  1756 new polymorphic constants (INCOMPATIBILITY):
  1757 
  1758   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  1759   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  1760   STAR_Un <-- {STAR,NatStar,STARC}_Un
  1761   STAR_Int <-- {STAR,NatStar,STARC}_Int
  1762   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  1763   STAR_subset <-- {STAR,NatStar,STARC}_subset
  1764   STAR_mem <-- {STAR,NatStar,STARC}_mem
  1765   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  1766   STAR_diff <-- {STAR,STARC}_diff
  1767   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  1768     STARC_hcomplex_of_complex}_image_subset
  1769   starset_n_Un <-- starset{Nat,C}_n_Un
  1770   starset_n_Int <-- starset{Nat,C}_n_Int
  1771   starset_n_Compl <-- starset{Nat,C}_n_Compl
  1772   starset_n_diff <-- starset{Nat,C}_n_diff
  1773   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  1774   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  1775   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  1776   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  1777   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  1778   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  1779   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  1780   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  1781   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  1782   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  1783   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  1784   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  1785   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  1786   starfun_diff <-- starfun{C,RC,CR}_diff
  1787   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  1788   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  1789   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  1790   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  1791   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  1792   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  1793   starfun_Id <-- starfunC_Id
  1794   starfun_approx <-- starfun{Nat,CR}_approx
  1795   starfun_capprox <-- starfun{C,RC}_capprox
  1796   starfun_abs <-- starfunNat_rabs
  1797   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  1798   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  1799   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  1800   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  1801   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  1802   starfun_add_approx <-- starfunCR_add_approx
  1803   starfun_inverse_inverse <-- starfunC_inverse_inverse
  1804   starfun_divide <-- starfun{C,CR,RC}_divide
  1805   starfun_n <-- starfun{Nat,C}_n
  1806   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1807   starfun_n_add <-- starfun{Nat,C}_n_add
  1808   starfun_n_add_minus <-- starfunNat_n_add_minus
  1809   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1810   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1811   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1812 
  1813   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1814   star_n_minus <-- {hypreal,hcomplex}_minus
  1815   star_n_diff <-- {hypreal,hcomplex}_diff
  1816   star_n_mult <-- {hypreal,hcomplex}_mult
  1817   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1818   star_n_le <-- {hypreal,hypnat}_le
  1819   star_n_less <-- {hypreal,hypnat}_less
  1820   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1821   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1822   star_n_abs <-- hypreal_hrabs
  1823   star_n_divide <-- hcomplex_divide
  1824 
  1825   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1826   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1827   star_of_diff <-- hypreal_of_real_diff
  1828   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1829   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1830   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1831   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1832   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1833   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1834   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1835   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1836   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1837   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1838   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1839   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1840   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1841   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1842   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1843   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1844   star_of_power <-- hypreal_of_real_power
  1845   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1846 
  1847 * Hyperreal: new method "transfer" that implements the transfer
  1848 principle of nonstandard analysis. With a subgoal that mentions
  1849 nonstandard types like "'a star", the command "apply transfer"
  1850 replaces it with an equivalent one that mentions only standard types.
  1851 To be successful, all free variables must have standard types; non-
  1852 standard variables must have explicit universal quantifiers.
  1853 
  1854 * Hyperreal: A theory of Taylor series.
  1855 
  1856 
  1857 *** HOLCF ***
  1858 
  1859 * Discontinued special version of 'constdefs' (which used to support
  1860 continuous functions) in favor of the general Pure one with full
  1861 type-inference.
  1862 
  1863 * New simplification procedure for solving continuity conditions; it
  1864 is much faster on terms with many nested lambda abstractions (cubic
  1865 instead of exponential time).
  1866 
  1867 * New syntax for domain package: selector names are now optional.
  1868 Parentheses should be omitted unless argument is lazy, for example:
  1869 
  1870   domain 'a stream = cons "'a" (lazy "'a stream")
  1871 
  1872 * New command 'fixrec' for defining recursive functions with pattern
  1873 matching; defining multiple functions with mutual recursion is also
  1874 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1875 sinr, or any data constructor defined by the domain package. The given
  1876 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1877 syntax and examples.
  1878 
  1879 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1880 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1881 but the proof obligation additionally includes an admissibility
  1882 requirement. The packages generate instances of class cpo or pcpo,
  1883 with continuity and strictness theorems for Rep and Abs.
  1884 
  1885 * HOLCF: Many theorems have been renamed according to a more standard naming
  1886 scheme (INCOMPATIBILITY):
  1887 
  1888   foo_inject:  "foo$x = foo$y ==> x = y"
  1889   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1890   foo_less:    "(foo$x << foo$y) = (x << y)"
  1891   foo_strict:  "foo$UU = UU"
  1892   foo_defined: "... ==> foo$x ~= UU"
  1893   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1894 
  1895 
  1896 *** ZF ***
  1897 
  1898 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1899 including the First Isomorphism Theorem (on quotienting by the kernel
  1900 of a homomorphism).
  1901 
  1902 * ZF/Simplifier: install second copy of type solver that actually
  1903 makes use of TC rules declared to Isar proof contexts (or locales);
  1904 the old version is still required for ML proof scripts.
  1905 
  1906 
  1907 *** Cube ***
  1908 
  1909 * Converted to Isar theory format; use locales instead of axiomatic
  1910 theories.
  1911 
  1912 
  1913 *** ML ***
  1914 
  1915 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  1916 for ||>, ||>>, |>>,
  1917 
  1918 * Pure/library.ML no longer defines its own option datatype, but uses
  1919 that of the SML basis, which has constructors NONE and SOME instead of
  1920 None and Some, as well as exception Option.Option instead of OPTION.
  1921 The functions the, if_none, is_some, is_none have been adapted
  1922 accordingly, while Option.map replaces apsome.
  1923 
  1924 * Pure/library.ML: the exception LIST has been given up in favour of
  1925 the standard exceptions Empty and Subscript, as well as
  1926 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1927 superceded by the standard hd and tl functions etc.
  1928 
  1929 A number of basic list functions are no longer exported to the ML
  1930 toplevel, as they are variants of predefined functions.  The following
  1931 suggests how one can translate existing code:
  1932 
  1933     rev_append xs ys = List.revAppend (xs, ys)
  1934     nth_elem (i, xs) = List.nth (xs, i)
  1935     last_elem xs = List.last xs
  1936     flat xss = List.concat xss
  1937     seq fs = List.app fs
  1938     partition P xs = List.partition P xs
  1939     mapfilter f xs = List.mapPartial f xs
  1940 
  1941 * Pure/library.ML: several combinators for linear functional
  1942 transformations, notably reverse application and composition:
  1943 
  1944   x |> f                f #> g
  1945   (x, y) |-> f          f #-> g
  1946 
  1947 * Pure/library.ML: introduced/changed precedence of infix operators:
  1948 
  1949   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1950   infix 2 ?;
  1951   infix 3 o oo ooo oooo;
  1952   infix 4 ~~ upto downto;
  1953 
  1954 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1955 infix operators.
  1956 
  1957 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1958 fold_map support linear functional transformations and nesting.  For
  1959 example:
  1960 
  1961   fold f [x1, ..., xN] y =
  1962     y |> f x1 |> ... |> f xN
  1963 
  1964   (fold o fold) f [xs1, ..., xsN] y =
  1965     y |> fold f xs1 |> ... |> fold f xsN
  1966 
  1967   fold f [x1, ..., xN] =
  1968     f x1 #> ... #> f xN
  1969 
  1970   (fold o fold) f [xs1, ..., xsN] =
  1971     fold f xs1 #> ... #> fold f xsN
  1972 
  1973 * Pure/library.ML: the following selectors on type 'a option are
  1974 available:
  1975 
  1976   the:               'a option -> 'a  (*partial*)
  1977   these:             'a option -> 'a  where 'a = 'b list
  1978   the_default: 'a -> 'a option -> 'a
  1979   the_list:          'a option -> 'a list
  1980 
  1981 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1982 basic operations for association lists, following natural argument
  1983 order; moreover the explicit equality predicate passed here avoids
  1984 potentially expensive polymorphic runtime equality checks.
  1985 The old functions may be expressed as follows:
  1986 
  1987   assoc = uncurry (AList.lookup (op =))
  1988   assocs = these oo AList.lookup (op =)
  1989   overwrite = uncurry (AList.update (op =)) o swap
  1990 
  1991 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1992 
  1993   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1994   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1995 
  1996 replacing make_keylist and keyfilter (occassionally used)
  1997 Naive rewrites:
  1998 
  1999   make_keylist = AList.make
  2000   keyfilter = AList.find (op =)
  2001 
  2002 * eq_fst and eq_snd now take explicit equality parameter, thus
  2003   avoiding eqtypes. Naive rewrites:
  2004 
  2005     eq_fst = eq_fst (op =)
  2006     eq_snd = eq_snd (op =)
  2007 
  2008 * Removed deprecated apl and apr (rarely used).
  2009   Naive rewrites:
  2010 
  2011     apl (n, op) =>>= curry op n
  2012     apr (op, m) =>>= fn n => op (n, m)
  2013 
  2014 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2015 provides a reasonably efficient light-weight implementation of sets as
  2016 lists.
  2017 
  2018 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2019 few new operations; existing lookup and update are now curried to
  2020 follow natural argument order (for use with fold etc.);
  2021 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2022 
  2023 * Pure/General: output via the Isabelle channels of
  2024 writeln/warning/error etc. is now passed through Output.output, with a
  2025 hook for arbitrary transformations depending on the print_mode
  2026 (cf. Output.add_mode -- the first active mode that provides a output
  2027 function wins).  Already formatted output may be embedded into further
  2028 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2029 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2030 accommodate easy composition of diagnostic messages etc.  Programmers
  2031 rarely need to care about Output.output or Output.raw at all, with
  2032 some notable exceptions: Output.output is required when bypassing the
  2033 standard channels (writeln etc.), or in token translations to produce
  2034 properly formatted results; Output.raw is required when capturing
  2035 already output material that will eventually be presented to the user
  2036 a second time.  For the default print mode, both Output.output and
  2037 Output.raw have no effect.
  2038 
  2039 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2040 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2041 cumulative results are displayed at the end of a batch session.
  2042 
  2043 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2044 replaced by File.platform_path and File.shell_path (with appropriate
  2045 hooks).  This provides a clean interface for unusual systems where the
  2046 internal and external process view of file names are different.
  2047 
  2048 * Pure: more efficient orders for basic syntactic entities: added
  2049 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2050 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2051 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2052 orders now -- potential INCOMPATIBILITY for code that depends on a
  2053 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2054 Library.sort_strings on result).
  2055 
  2056 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2057 fold_types traverse types/terms from left to right, observing natural
  2058 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2059 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2060 
  2061 * Pure: name spaces have been refined, with significant changes of the
  2062 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2063 to extern(_table).  The plain name entry path is superceded by a
  2064 general 'naming' context, which also includes the 'policy' to produce
  2065 a fully qualified name and external accesses of a fully qualified
  2066 name; NameSpace.extend is superceded by context dependent
  2067 Sign.declare_name.  Several theory and proof context operations modify
  2068 the naming context.  Especially note Theory.restore_naming and
  2069 ProofContext.restore_naming to get back to a sane state; note that
  2070 Theory.add_path is no longer sufficient to recover from
  2071 Theory.absolute_path in particular.
  2072 
  2073 * Pure: new flags short_names (default false) and unique_names
  2074 (default true) for controlling output of qualified names.  If
  2075 short_names is set, names are printed unqualified.  If unique_names is
  2076 reset, the name prefix is reduced to the minimum required to achieve
  2077 the original result when interning again, even if there is an overlap
  2078 with earlier declarations.
  2079 
  2080 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2081 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2082 (useful for printing error messages).  INCOMPATIBILITY.
  2083 
  2084 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2085 Theory.theory are now identified, referring to the universal
  2086 Context.theory (see Pure/context.ML).  Actual signature and theory
  2087 content is managed as theory data.  The old code and interfaces were
  2088 spread over many files and structures; the new arrangement introduces
  2089 considerable INCOMPATIBILITY to gain more clarity:
  2090 
  2091   Context -- theory management operations (name, identity, inclusion,
  2092     parents, ancestors, merge, etc.), plus generic theory data;
  2093 
  2094   Sign -- logical signature and syntax operations (declaring consts,
  2095     types, etc.), plus certify/read for common entities;
  2096 
  2097   Theory -- logical theory operations (stating axioms, definitions,
  2098     oracles), plus a copy of logical signature operations (consts,
  2099     types, etc.); also a few basic management operations (Theory.copy,
  2100     Theory.merge, etc.)
  2101 
  2102 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2103 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2104 for convenience -- they merely return the theory.
  2105 
  2106 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2107 
  2108 * Pure: the Isar proof context type is already defined early in Pure
  2109 as Context.proof (note that ProofContext.context and Proof.context are
  2110 aliases, where the latter is the preferred name).  This enables other
  2111 Isabelle components to refer to that type even before Isar is present.
  2112 
  2113 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2114 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2115 any of these kinds.  For example, Sign.intern typeK is now
  2116 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2117 Theory.hide_types.  Also note that former
  2118 Theory.hide_classes/types/consts are now
  2119 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2120 internalize their arguments!  INCOMPATIBILITY.
  2121 
  2122 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2123 datatype thmref (with constructors Name and NameSelection) instead of
  2124 plain string -- INCOMPATIBILITY;
  2125 
  2126 * Pure: cases produced by proof methods specify options, where NONE
  2127 means to remove case bindings -- INCOMPATIBILITY in
  2128 (RAW_)METHOD_CASES.
  2129 
  2130 * Pure: the following operations retrieve axioms or theorems from a
  2131 theory node or theory hierarchy, respectively:
  2132 
  2133   Theory.axioms_of: theory -> (string * term) list
  2134   Theory.all_axioms_of: theory -> (string * term) list
  2135   PureThy.thms_of: theory -> (string * thm) list
  2136   PureThy.all_thms_of: theory -> (string * thm) list
  2137 
  2138 * Pure: print_tac now outputs the goal through the trace channel.
  2139 
  2140 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2141 Reference Toplevel.debug (default false) controls detailed printing
  2142 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2143 controls execution profiling -- set to 1 for time and 2 for space
  2144 (both increase the runtime).
  2145 
  2146 * Isar session: The initial use of ROOT.ML is now always timed,
  2147 i.e. the log will show the actual process times, in contrast to the
  2148 elapsed wall-clock time that the outer shell wrapper produces.
  2149 
  2150 * Simplifier: improved handling of bound variables (nameless
  2151 representation, avoid allocating new strings).  Simprocs that invoke
  2152 the Simplifier recursively should use Simplifier.inherit_bounds to
  2153 avoid local name clashes.  Failure to do so produces warnings
  2154 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2155 for further details.
  2156 
  2157 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2158 bindings for all theorems stored within a given theory; this may help
  2159 in porting non-Isar theories to Isar ones, while keeping ML proof
  2160 scripts for the time being.
  2161 
  2162 * ML operator HTML.with_charset specifies the charset begin used for
  2163 generated HTML files.  For example:
  2164 
  2165   HTML.with_charset "utf-8" use_thy "Hebrew";
  2166   HTML.with_charset "utf-8" use_thy "Chinese";
  2167 
  2168 
  2169 *** System ***
  2170 
  2171 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2172 isabelle, isatool etc.).
  2173 
  2174 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2175 isatool doc, isatool mkdir, display_drafts etc.).
  2176 
  2177 * isatool usedir: option -f allows specification of the ML file to be
  2178 used by Isabelle; default is ROOT.ML.
  2179 
  2180 * New isatool version outputs the version identifier of the Isabelle
  2181 distribution being used.
  2182 
  2183 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2184 (containing Boolean satisfiability problems) into Isabelle/HOL
  2185 theories.
  2186 
  2187 
  2188 
  2189 New in Isabelle2004 (April 2004)
  2190 --------------------------------
  2191 
  2192 *** General ***
  2193 
  2194 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2195   Replaces linorder.ML.
  2196 
  2197 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2198   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2199   (\<a>...\<z>), are now considered normal letters, and can therefore
  2200   be used anywhere where an ASCII letter (a...zA...Z) has until
  2201   now. COMPATIBILITY: This obviously changes the parsing of some
  2202   terms, especially where a symbol has been used as a binder, say
  2203   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2204   as an identifier.  Fix it by inserting a space around former
  2205   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2206   existing theory and ML files.
  2207 
  2208 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2209 
  2210 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2211   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2212   a normal (but invisible) letter. For multiple letter subscripts repeat
  2213   \<^isub> like this: x\<^isub>1\<^isub>2.
  2214 
  2215 * Pure: There are now sub-/superscripts that can span more than one
  2216   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2217   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2218   superscript. The new control characters are not identifier parts.
  2219 
  2220 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2221   content of "..." to the latex file instead of \isacntrl... . The "..."
  2222   may consist of any printable characters excluding the end bracket >.
  2223 
  2224 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2225   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2226   declare constants "final", which prevents their being given a definition
  2227   later.  It is useful for constants whose behaviour is fixed axiomatically
  2228   rather than definitionally, such as the meta-logic connectives.
  2229 
  2230 * Pure: 'instance' now handles general arities with general sorts
  2231   (i.e. intersections of classes),
  2232 
  2233 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2234   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2235   It can be changed to alter the colors/layout of generated pages.
  2236 
  2237 
  2238 *** Isar ***
  2239 
  2240 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2241   cut_tac, subgoal_tac and thin_tac:
  2242   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2243     locales are no longer forced to write Isar proof scripts.
  2244     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2245     emulations.
  2246   - INCOMPATIBILITY: names of variables to be instantiated may no
  2247     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2248     This is consistent with the instantiation attribute "where".
  2249 
  2250 * Attributes "where" and "of":
  2251   - Now take type variables of instantiated theorem into account when reading
  2252     the instantiation string.  This fixes a bug that caused instantiated
  2253     theorems to have too special types in some circumstances.
  2254   - "where" permits explicit instantiations of type variables.
  2255 
  2256 * Calculation commands "moreover" and "also" no longer interfere with
  2257   current facts ("this"), admitting arbitrary combinations with "then"
  2258   and derived forms.
  2259 
  2260 * Locales:
  2261   - Goal statements involving the context element "includes" no longer
  2262     generate theorems with internal delta predicates (those ending on
  2263     "_axioms") in the premise.
  2264     Resolve particular premise with <locale>.intro to obtain old form.
  2265   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2266     specification and "includes" elements in goal statement.
  2267   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2268     [intro?] and [elim?] (respectively) by default.
  2269   - Experimental command for instantiation of locales in proof contexts:
  2270         instantiate <label>[<attrs>]: <loc>
  2271     Instantiates locale <loc> and adds all its theorems to the current context
  2272     taking into account their attributes.  Label and attrs are optional
  2273     modifiers, like in theorem declarations.  If present, names of
  2274     instantiated theorems are qualified with <label>, and the attributes
  2275     <attrs> are applied after any attributes these theorems might have already.
  2276       If the locale has assumptions, a chained fact of the form
  2277     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2278     are derived.  The command does not support old-style locales declared
  2279     with "locale (open)".
  2280       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2281 
  2282 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2283   (Isar) contexts.
  2284 
  2285 
  2286 *** HOL ***
  2287 
  2288 * Proof import: new image HOL4 contains the imported library from
  2289   the HOL4 system with about 2500 theorems. It is imported by
  2290   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2291   can be used like any other Isabelle image.  See
  2292   HOL/Import/HOL/README for more information.
  2293 
  2294 * Simplifier:
  2295   - Much improved handling of linear and partial orders.
  2296     Reasoners for linear and partial orders are set up for type classes
  2297     "linorder" and "order" respectively, and are added to the default simpset
  2298     as solvers.  This means that the simplifier can build transitivity chains
  2299     to solve goals from the assumptions.
  2300   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2301     of blast or auto after simplification become unnecessary because the goal
  2302     is solved by simplification already.
  2303 
  2304 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2305     all proved in axiomatic type classes for semirings, rings and fields.
  2306 
  2307 * Numerics:
  2308   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2309     now formalized using the Ring_and_Field theory mentioned above.
  2310   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2311     than before, because now they are set up once in a generic manner.
  2312   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2313     Look for the general versions in Ring_and_Field (and Power if they concern
  2314     exponentiation).
  2315 
  2316 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2317 
  2318 * Records:
  2319   - Record types are now by default printed with their type abbreviation
  2320     instead of the list of all field types. This can be configured via
  2321     the reference "print_record_type_abbr".
  2322   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2323     (not enabled by default).
  2324   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2325     EX x. x = sel r to True (not enabled by default).
  2326   - Tactic "record_split_simp_tac" to split and simplify records added.
  2327 
  2328 * 'specification' command added, allowing for definition by
  2329   specification.  There is also an 'ax_specification' command that
  2330   introduces the new constants axiomatically.
  2331 
  2332 * arith(_tac) is now able to generate counterexamples for reals as well.
  2333 
  2334 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2335 
  2336 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2337   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2338 
  2339 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2340   matrix theory to linear programming.
  2341 
  2342 * Unions and Intersections:
  2343   The latex output syntax of UN and INT has been changed
  2344   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2345   i.e. the index formulae has become a subscript.
  2346   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2347 
  2348 * Unions and Intersections over Intervals:
  2349   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2350   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2351   like in normal math, and corresponding versions for < and for intersection.
  2352 
  2353 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2354   lexicographic dictonary ordering has been added as "lexord".
  2355 
  2356 * ML: the legacy theory structures Int and List have been removed. They had
  2357   conflicted with ML Basis Library structures having the same names.
  2358 
  2359 * 'refute' command added to search for (finite) countermodels.  Only works
  2360   for a fragment of HOL.  The installation of an external SAT solver is
  2361   highly recommended.  See "HOL/Refute.thy" for details.
  2362 
  2363 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2364   formulae under an assignment of free variables to random values.
  2365   In contrast to 'refute', it can deal with inductive datatypes,
  2366   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2367   for examples.
  2368 
  2369 
  2370 *** HOLCF ***
  2371 
  2372 * Streams now come with concatenation and are part of the HOLCF image
  2373 
  2374 
  2375 
  2376 New in Isabelle2003 (May 2003)
  2377 ------------------------------
  2378 
  2379 *** General ***
  2380 
  2381 * Provers/simplifier:
  2382 
  2383   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2384     Assumptions are now subject to complete mutual simplification,
  2385     not just from left to right. The simplifier now preserves
  2386     the order of assumptions.
  2387 
  2388     Potential INCOMPATIBILITY:
  2389 
  2390     -- simp sometimes diverges where the old version did
  2391        not, e.g. invoking simp on the goal
  2392 
  2393         [| P (f x); y = x; f x = f y |] ==> Q
  2394 
  2395        now gives rise to the infinite reduction sequence
  2396 
  2397         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2398 
  2399        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2400        kind of problem.
  2401 
  2402     -- Tactics combining classical reasoner and simplification (such as auto)
  2403        are also affected by this change, because many of them rely on
  2404        simp. They may sometimes diverge as well or yield a different numbers
  2405        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2406        in case of problems. Sometimes subsequent calls to the classical
  2407        reasoner will fail because a preceeding call to the simplifier too
  2408        eagerly simplified the goal, e.g. deleted redundant premises.
  2409 
  2410   - The simplifier trace now shows the names of the applied rewrite rules
  2411 
  2412   - You can limit the number of recursive invocations of the simplifier
  2413     during conditional rewriting (where the simplifie tries to solve the
  2414     conditions before applying the rewrite rule):
  2415     ML "simp_depth_limit := n"
  2416     where n is an integer. Thus you can force termination where previously
  2417     the simplifier would diverge.
  2418 
  2419   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2420 
  2421   - No longer aborts on failed congruence proof.  Instead, the
  2422     congruence is ignored.
  2423 
  2424 * Pure: New generic framework for extracting programs from constructive
  2425   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2426   as HOL/Extraction for some case studies.
  2427 
  2428 * Pure: The main goal of the proof state is no longer shown by default, only
  2429 the subgoals. This behaviour is controlled by a new flag.
  2430    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2431 (ML: Proof.show_main_goal).
  2432 
  2433 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2434 rules whose conclusion matches subgoal 1:
  2435       PG menu: Isabelle/Isar -> Show me -> matching rules
  2436 The rules are ordered by how closely they match the subgoal.
  2437 In particular, rules that solve a subgoal outright are displayed first
  2438 (or rather last, the way they are printed).
  2439 (ML: ProofGeneral.print_intros())
  2440 
  2441 * Pure: New flag trace_unify_fail causes unification to print
  2442 diagnostic information (PG: in trace buffer) when it fails. This is
  2443 useful for figuring out why single step proofs like rule, erule or
  2444 assumption failed.
  2445 
  2446 * Pure: Locale specifications now produce predicate definitions
  2447 according to the body of text (covering assumptions modulo local
  2448 definitions); predicate "loc_axioms" covers newly introduced text,
  2449 while "loc" is cumulative wrt. all included locale expressions; the
  2450 latter view is presented only on export into the global theory
  2451 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2452 on the old view without predicates;
  2453 
  2454 * Pure: predefined locales "var" and "struct" are useful for sharing
  2455 parameters (as in CASL, for example); just specify something like
  2456 ``var x + var y + struct M'' as import;
  2457 
  2458 * Pure: improved thms_containing: proper indexing of facts instead of
  2459 raw theorems; check validity of results wrt. current name space;
  2460 include local facts of proof configuration (also covers active
  2461 locales), cover fixed variables in index; may use "_" in term
  2462 specification; an optional limit for the number of printed facts may
  2463 be given (the default is 40);
  2464 
  2465 * Pure: disallow duplicate fact bindings within new-style theory files
  2466 (batch-mode only);
  2467 
  2468 * Provers: improved induct method: assumptions introduced by case
  2469 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2470 the goal statement); "foo" still refers to all facts collectively;
  2471 
  2472 * Provers: the function blast.overloaded has been removed: all constants
  2473 are regarded as potentially overloaded, which improves robustness in exchange
  2474 for slight decrease in efficiency;
  2475 
  2476 * Provers/linorder: New generic prover for transitivity reasoning over
  2477 linear orders.  Note: this prover is not efficient!
  2478 
  2479 * Isar: preview of problems to finish 'show' now produce an error
  2480 rather than just a warning (in interactive mode);
  2481 
  2482 
  2483 *** HOL ***
  2484 
  2485 * arith(_tac)
  2486 
  2487  - Produces a counter example if it cannot prove a goal.
  2488    Note that the counter example may be spurious if the goal is not a formula
  2489    of quantifier-free linear arithmetic.
  2490    In ProofGeneral the counter example appears in the trace buffer.
  2491 
  2492  - Knows about div k and mod k where k is a numeral of type nat or int.
  2493 
  2494  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2495    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2496    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2497 
  2498 * simp's arithmetic capabilities have been enhanced a bit: it now
  2499 takes ~= in premises into account (by performing a case split);
  2500 
  2501 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2502 are distributed over a sum of terms;
  2503 
  2504 * New tactic "trans_tac" and method "trans" instantiate
  2505 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2506 "<=", "<" and "=").
  2507 
  2508 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2509 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2510 
  2511 * 'typedef' command has new option "open" to suppress the set
  2512 definition;
  2513 
  2514 * functions Min and Max on finite sets have been introduced (theory
  2515 Finite_Set);
  2516 
  2517 * attribute [symmetric] now works for relations as well; it turns
  2518 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2519 
  2520 * induct over a !!-quantified statement (say !!x1..xn):
  2521   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2522 
  2523 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2524 %x. None. Warning: empty_def now refers to the previously hidden definition
  2525 of the empty set.
  2526 
  2527 * Algebra: formalization of classical algebra.  Intended as base for
  2528 any algebraic development in Isabelle.  Currently covers group theory
  2529 (up to Sylow's theorem) and ring theory (Universal Property of
  2530 Univariate Polynomials).  Contributions welcome;
  2531 
  2532 * GroupTheory: deleted, since its material has been moved to Algebra;
  2533 
  2534 * Complex: new directory of the complex numbers with numeric constants,
  2535 nonstandard complex numbers, and some complex analysis, standard and
  2536 nonstandard (Jacques Fleuriot);
  2537 
  2538 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2539 
  2540 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2541 Fleuriot);
  2542 
  2543 * Real/HahnBanach: updated and adapted to locales;
  2544 
  2545 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2546 Gray and Kramer);
  2547 
  2548 * UNITY: added the Meier-Sanders theory of progress sets;
  2549 
  2550 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2551 as abstract algorithms, instantiated to the JVM;
  2552 
  2553 * Bali: Java source language formalization. Type system, operational
  2554 semantics, axiomatic semantics. Supported language features:
  2555 classes, interfaces, objects,virtual methods, static methods,
  2556 static/instance fields, arrays, access modifiers, definite
  2557 assignment, exceptions.
  2558 
  2559 
  2560 *** ZF ***
  2561 
  2562 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2563 universe, etc.);
  2564 
  2565 * Main ZF: virtually all theories converted to new-style format;
  2566 
  2567 
  2568 *** ML ***
  2569 
  2570 * Pure: Tactic.prove provides sane interface for internal proofs;
  2571 omits the infamous "standard" operation, so this is more appropriate
  2572 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2573 
  2574 * Pure: improved error reporting of simprocs;
  2575 
  2576 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2577 up simprocs;
  2578 
  2579 
  2580 *** Document preparation ***
  2581 
  2582 * uses \par instead of \\ for line breaks in theory text. This may
  2583 shift some page breaks in large documents. To get the old behaviour
  2584 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2585 
  2586 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2587 other packages
  2588 
  2589 * \<euro> now needs package babel/greek instead of marvosym (which
  2590 broke \Rightarrow)
  2591 
  2592 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2593 textcomp package)
  2594 
  2595 
  2596 
  2597 New in Isabelle2002 (March 2002)
  2598 --------------------------------
  2599 
  2600 *** Document preparation ***
  2601 
  2602 * greatly simplified document preparation setup, including more
  2603 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2604 instructive isatool mkdir; users should basically be able to get
  2605 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2606 users may run a separate document processing stage manually like this:
  2607 "isatool usedir -D output HOL Test && isatool document Test/output";
  2608 
  2609 * theory dependency graph may now be incorporated into documents;
  2610 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2611 with \includegraphics of LaTeX;
  2612 
  2613 * proper spacing of consecutive markup elements, especially text
  2614 blocks after section headings;
  2615 
  2616 * support bold style (for single symbols only), input syntax is like
  2617 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2618 
  2619 * \<bullet> is now output as bold \cdot by default, which looks much
  2620 better in printed text;
  2621 
  2622 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2623 note that these symbols are currently unavailable in Proof General /
  2624 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2625 
  2626 * isatool latex no longer depends on changed TEXINPUTS, instead
  2627 isatool document copies the Isabelle style files to the target
  2628 location;
  2629 
  2630 
  2631 *** Isar ***
  2632 
  2633 * Pure/Provers: improved proof by cases and induction;
  2634   - 'case' command admits impromptu naming of parameters (such as
  2635     "case (Suc n)");
  2636   - 'induct' method divinates rule instantiation from the inductive
  2637     claim; no longer requires excessive ?P bindings for proper
  2638     instantiation of cases;
  2639   - 'induct' method properly enumerates all possibilities of set/type
  2640     rules; as a consequence facts may be also passed through *type*
  2641     rules without further ado;
  2642   - 'induct' method now derives symbolic cases from the *rulified*
  2643     rule (before it used to rulify cases stemming from the internal
  2644     atomized version); this means that the context of a non-atomic
  2645     statement becomes is included in the hypothesis, avoiding the
  2646     slightly cumbersome show "PROP ?case" form;
  2647   - 'induct' may now use elim-style induction rules without chaining
  2648     facts, using ``missing'' premises from the goal state; this allows
  2649     rules stemming from inductive sets to be applied in unstructured
  2650     scripts, while still benefitting from proper handling of non-atomic
  2651     statements; NB: major inductive premises need to be put first, all
  2652     the rest of the goal is passed through the induction;
  2653   - 'induct' proper support for mutual induction involving non-atomic
  2654     rule statements (uses the new concept of simultaneous goals, see
  2655     below);
  2656   - append all possible rule selections, but only use the first
  2657     success (no backtracking);
  2658   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  2659   - undeclared rule case names default to numbers 1, 2, 3, ...;
  2660   - added 'print_induct_rules' (covered by help item in recent Proof
  2661     General versions);
  2662   - moved induct/cases attributes to Pure, methods to Provers;
  2663   - generic method setup instantiated for FOL and HOL;
  2664 
  2665 * Pure: support multiple simultaneous goal statements, for example
  2666 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  2667 meta-level mechanism, this acts as if several individual goals had
  2668 been stated separately; in particular common proof methods need to be
  2669 repeated in order to cover all claims; note that a single elimination
  2670 step is *not* sufficient to establish the two conjunctions, so this
  2671 fails:
  2672 
  2673   assume "A & B" then have A and B ..   (*".." fails*)
  2674 
  2675 better use "obtain" in situations as above; alternative refer to
  2676 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  2677 
  2678 * Pure: proper integration with ``locales''; unlike the original
  2679 version by Florian Kammller, Isar locales package high-level proof
  2680 contexts rather than raw logical ones (e.g. we admit to include
  2681 attributes everywhere); operations on locales include merge and
  2682 rename; support for implicit arguments (``structures''); simultaneous
  2683 type-inference over imports and text; see also HOL/ex/Locales.thy for
  2684 some examples;
  2685 
  2686 * Pure: the following commands have been ``localized'', supporting a
  2687 target locale specification "(in name)": 'lemma', 'theorem',
  2688 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  2689 stored both within the locale and at the theory level (exported and
  2690 qualified by the locale name);
  2691 
  2692 * Pure: theory goals may now be specified in ``long'' form, with
  2693 ad-hoc contexts consisting of arbitrary locale elements. for example
  2694 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  2695 definitions may be given, too); the result is a meta-level rule with
  2696 the context elements being discharged in the obvious way;
  2697 
  2698 * Pure: new proof command 'using' allows to augment currently used
  2699 facts after a goal statement ('using' is syntactically analogous to
  2700 'apply', but acts on the goal's facts only); this allows chained facts
  2701 to be separated into parts given before and after a claim, as in
  2702 ``from a and b have C using d and e <proof>'';
  2703 
  2704 * Pure: renamed "antecedent" case to "rule_context";
  2705 
  2706 * Pure: new 'judgment' command records explicit information about the
  2707 object-logic embedding (used by several tools internally); no longer
  2708 use hard-wired "Trueprop";
  2709 
  2710 * Pure: added 'corollary' command;
  2711 
  2712 * Pure: fixed 'token_translation' command;
  2713 
  2714 * Pure: removed obsolete 'exported' attribute;
  2715 
  2716 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  2717 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  2718 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  2719 
  2720 * Pure: method 'atomize' presents local goal premises as object-level
  2721 statements (atomic meta-level propositions); setup controlled via
  2722 rewrite rules declarations of 'atomize' attribute; example
  2723 application: 'induct' method with proper rule statements in improper
  2724 proof *scripts*;
  2725 
  2726 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  2727 now consider the syntactic context of assumptions, giving a better
  2728 chance to get type-inference of the arguments right (this is
  2729 especially important for locales);
  2730 
  2731 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  2732 mode;
  2733 
  2734 * Pure/obtain: the formal conclusion "thesis", being marked as
  2735 ``internal'', may no longer be reference directly in the text;
  2736 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  2737 situations;
  2738 
  2739 * Pure: generic 'sym' attribute which declares a rule both as pure
  2740 'elim?' and for the 'symmetric' operation;
  2741 
  2742 * Pure: marginal comments ``--'' may now occur just anywhere in the
  2743 text; the fixed correlation with particular command syntax has been
  2744 discontinued;
  2745 
  2746 * Pure: new method 'rules' is particularly well-suited for proof
  2747 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  2748 but often produces more compact proof terms with less detours;
  2749 
  2750 * Pure/Provers/classical: simplified integration with pure rule
  2751 attributes and methods; the classical "intro?/elim?/dest?"
  2752 declarations coincide with the pure ones; the "rule" method no longer
  2753 includes classically swapped intros; "intro" and "elim" methods no
  2754 longer pick rules from the context; also got rid of ML declarations
  2755 AddXIs/AddXEs/AddXDs; all of this has some potential for
  2756 INCOMPATIBILITY;
  2757 
  2758 * Provers/classical: attribute 'swapped' produces classical inversions
  2759 of introduction rules;
  2760 
  2761 * Provers/simplifier: 'simplified' attribute may refer to explicit
  2762 rules instead of full simplifier context; 'iff' attribute handles
  2763 conditional rules;
  2764 
  2765 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  2766 
  2767 * HOL: 'recdef' now fails on unfinished automated proofs, use
  2768 "(permissive)" option to recover old behavior;
  2769 
  2770 * HOL: 'inductive' no longer features separate (collective) attributes
  2771 for 'intros' (was found too confusing);
  2772 
  2773 * HOL: properly declared induction rules less_induct and
  2774 wf_induct_rule;
  2775 
  2776 
  2777 *** HOL ***
  2778 
  2779 * HOL: moved over to sane numeral syntax; the new policy is as
  2780 follows:
  2781 
  2782   - 0 and 1 are polymorphic constants, which are defined on any
  2783   numeric type (nat, int, real etc.);
  2784 
  2785   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  2786   binary representation internally;
  2787 
  2788   - type nat has special constructor Suc, and generally prefers Suc 0
  2789   over 1::nat and Suc (Suc 0) over 2::nat;
  2790 
  2791 This change may cause significant problems of INCOMPATIBILITY; here
  2792 are some hints on converting existing sources:
  2793 
  2794   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  2795   entities, so expressions involving "-" (unary or binary minus) need
  2796   to be spaced properly;
  2797 
  2798   - existing occurrences of "1" may need to be constraint "1::nat" or
  2799   even replaced by Suc 0; similar for old "2";
  2800 
  2801   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  2802 
  2803   - remove all special provisions on numerals in proofs;
  2804 
  2805 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  2806 representation (depends on bin_arith_simps in the default context);
  2807 
  2808 * HOL: symbolic syntax for x^2 (numeral 2);
  2809 
  2810 * HOL: the class of all HOL types is now called "type" rather than
  2811 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2812 in axclass/classes, instance/arities, and (usually rare) occurrences
  2813 in typings (of consts etc.); internally the class is called
  2814 "HOL.type", ML programs should refer to HOLogic.typeS;
  2815 
  2816 * HOL/record package improvements:
  2817   - new derived operations "fields" to build a partial record section,
  2818     "extend" to promote a fixed record to a record scheme, and
  2819     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2820     declared as simp by default;
  2821   - shared operations ("more", "fields", etc.) now need to be always
  2822     qualified) --- potential INCOMPATIBILITY;
  2823   - removed "make_scheme" operations (use "make" with "extend") --
  2824     INCOMPATIBILITY;
  2825   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2826   - provides cases/induct rules for use with corresponding Isar
  2827     methods (for concrete records, record schemes, concrete more
  2828     parts, and schematic more parts -- in that order);
  2829   - internal definitions directly based on a light-weight abstract
  2830     theory of product types over typedef rather than datatype;
  2831 
  2832 * HOL: generic code generator for generating executable ML code from
  2833 specifications; specific support for HOL constructs such as inductive
  2834 datatypes and sets, as well as recursive functions; can be invoked
  2835 via 'generate_code' theory section;
  2836 
  2837 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2838 
  2839 * HOL: consolidated and renamed several theories.  In particular:
  2840         Ord.thy has been absorbed into HOL.thy
  2841         String.thy has been absorbed into List.thy
  2842 
  2843 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2844 (beware of argument permutation!);
  2845 
  2846 * HOL: linorder_less_split superseded by linorder_cases;
  2847 
  2848 * HOL/List: "nodups" renamed to "distinct";
  2849 
  2850 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2851 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2852   - Ex_def has changed, now need to use some_eq_ex
  2853 
  2854 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2855 in this (rare) case use:
  2856 
  2857   delSWrapper "split_all_tac"
  2858   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2859 
  2860 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2861 MAY FAIL;
  2862 
  2863 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2864 Isabelle's type classes, ^ on functions and relations has too general
  2865 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2866 necessary to attach explicit type constraints;
  2867 
  2868 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2869 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2870 renamed accordingly (eg "compI" -> "rel_compI").
  2871 
  2872 * HOL: syntax translations now work properly with numerals and records
  2873 expressions;
  2874 
  2875 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2876 of "lam" -- INCOMPATIBILITY;
  2877 
  2878 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2879 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2880 renamed "Product_Type.unit";
  2881 
  2882 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2883 
  2884 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2885 the "cases" method);
  2886 
  2887 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2888 Florian Kammller);
  2889 
  2890 * HOL/IMP: updated and converted to new-style theory format; several
  2891 parts turned into readable document, with proper Isar proof texts and
  2892 some explanations (by Gerwin Klein);
  2893 
  2894 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2895 
  2896 * HOL-Hyperreal is now a logic image;
  2897 
  2898 
  2899 *** HOLCF ***
  2900 
  2901 * Isar: consts/constdefs supports mixfix syntax for continuous
  2902 operations;
  2903 
  2904 * Isar: domain package adapted to new-style theory format, e.g. see
  2905 HOLCF/ex/Dnat.thy;
  2906 
  2907 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2908 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2909 lift.induct_tac, always use UU instead of Undef;
  2910 
  2911 * HOLCF/IMP: updated and converted to new-style theory;
  2912 
  2913 
  2914 *** ZF ***
  2915 
  2916 * Isar: proper integration of logic-specific tools and packages,
  2917 including theory commands '(co)inductive', '(co)datatype',
  2918 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2919 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2920 
  2921 * theory Main no longer includes AC; for the Axiom of Choice, base
  2922 your theory on Main_ZFC;
  2923 
  2924 * the integer library now covers quotients and remainders, with many
  2925 laws relating division to addition, multiplication, etc.;
  2926 
  2927 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2928 typeless version of the formalism;
  2929 
  2930 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2931 format;
  2932 
  2933 * ZF/Induct: new directory for examples of inductive definitions,
  2934 including theory Multiset for multiset orderings; converted to
  2935 new-style theory format;
  2936 
  2937 * ZF: many new theorems about lists, ordinals, etc.;
  2938 
  2939 
  2940 *** General ***
  2941 
  2942 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2943 variable proof controls level of detail: 0 = no proofs (only oracle
  2944 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2945 also ref manual for further ML interfaces;
  2946 
  2947 * Pure/axclass: removed obsolete ML interface
  2948 goal_subclass/goal_arity;
  2949 
  2950 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2951 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2952 separate tokens, so expressions involving minus need to be spaced
  2953 properly;
  2954 
  2955 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2956 rather than "infixl" or "infixr";
  2957 
  2958 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2959 sort constraint specifications in type inference; e.g. "x::_::foo"
  2960 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2961 type variable);
  2962 
  2963 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2964 control output of nested => (types); the default behavior is
  2965 "type_brackets";
  2966 
  2967 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2968 tokens into AST constants;
  2969 
  2970 * Pure/syntax: prefer later declarations of translations and print
  2971 translation functions; potential INCOMPATIBILITY: need to reverse
  2972 multiple declarations for same syntax element constant;
  2973 
  2974 * Pure/show_hyps reset by default (in accordance to existing Isar
  2975 practice);
  2976 
  2977 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2978 addSafter;
  2979 
  2980 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2981 as well;
  2982 
  2983 * system: tested support for MacOS X; should be able to get Isabelle +
  2984 Proof General to work in a plain Terminal after installing Poly/ML
  2985 (e.g. from the Isabelle distribution area) and GNU bash alone
  2986 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2987 support requires further installations, e.g. from
  2988 http://fink.sourceforge.net/);
  2989 
  2990 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2991 
  2992 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2993 of 40 MB), cf. ML_OPTIONS;
  2994 
  2995 * system: Proof General keywords specification is now part of the
  2996 Isabelle distribution (see etc/isar-keywords.el);
  2997 
  2998 * system: support for persistent Proof General sessions (refrain from
  2999 outdating all loaded theories on startup); user may create writable
  3000 logic images like this: ``isabelle -q HOL Test'';
  3001 
  3002 * system: smart selection of Isabelle process versus Isabelle
  3003 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3004 run both "isabelle" and "Isabelle" even if file names are badly
  3005 damaged (executable inspects the case of the first letter of its own
  3006 name); added separate "isabelle-process" and "isabelle-interface";
  3007 
  3008 * system: refrain from any attempt at filtering input streams; no
  3009 longer support ``8bit'' encoding of old isabelle font, instead proper
  3010 iso-latin characters may now be used; the related isatools
  3011 "symbolinput" and "nonascii" have disappeared as well;
  3012 
  3013 * system: removed old "xterm" interface (the print modes "xterm" and
  3014 "xterm_color" are still available for direct use in a suitable
  3015 terminal);
  3016 
  3017 
  3018 
  3019 New in Isabelle99-2 (February 2001)
  3020 -----------------------------------
  3021 
  3022 *** Overview of INCOMPATIBILITIES ***
  3023 
  3024 * HOL: please note that theories in the Library and elsewhere often use the
  3025 new-style (Isar) format; to refer to their theorems in an ML script you must
  3026 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3027 
  3028 * HOL: inductive package no longer splits induction rule aggressively,
  3029 but only as far as specified by the introductions given; the old
  3030 format may be recovered via ML function complete_split_rule or attribute
  3031 'split_rule (complete)';
  3032 
  3033 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3034 gfp_Tarski to gfp_unfold;
  3035 
  3036 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3037 
  3038 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3039 relation); infix "^^" has been renamed "``"; infix "``" has been
  3040 renamed "`"; "univalent" has been renamed "single_valued";
  3041 
  3042 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3043 operation;
  3044 
  3045 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3046 
  3047 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3048 
  3049 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3050 consequence, it is no longer monotonic wrt. the local goal context
  3051 (which is now passed through the inductive cases);
  3052 
  3053 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3054 \<gg> to \<ggreater>;
  3055 
  3056 
  3057 *** Document preparation ***
  3058 
  3059 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3060 available: are "it" for near math-mode best-style output, "sl" for
  3061 slanted text style, and "tt" for plain type-writer; if no
  3062 \isabellestyle command is given, output is according to slanted
  3063 type-writer);
  3064 
  3065 * support sub/super scripts (for single symbols only), input syntax is
  3066 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3067 
  3068 * some more standard symbols; see Appendix A of the system manual for
  3069 the complete list of symbols defined in isabellesym.sty;
  3070 
  3071 * improved isabelle style files; more abstract symbol implementation
  3072 (should now use \isamath{...} and \isatext{...} in custom symbol
  3073 definitions);
  3074 
  3075 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3076 state; Note that presentation of goal states does not conform to
  3077 actual human-readable proof documents.  Please do not include goal
  3078 states into document output unless you really know what you are doing!
  3079 
  3080 * proper indentation of antiquoted output with proportional LaTeX
  3081 fonts;
  3082 
  3083 * no_document ML operator temporarily disables LaTeX document
  3084 generation;
  3085 
  3086 * isatool unsymbolize tunes sources for plain ASCII communication;
  3087 
  3088 
  3089 *** Isar ***
  3090 
  3091 * Pure: Isar now suffers initial goal statements to contain unbound
  3092 schematic variables (this does not conform to actual readable proof
  3093 documents, due to unpredictable outcome and non-compositional proof
  3094 checking); users who know what they are doing may use schematic goals
  3095 for Prolog-style synthesis of proven results;
  3096 
  3097 * Pure: assumption method (an implicit finishing) now handles actual
  3098 rules as well;
  3099 
  3100 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3101 initial goal, declare "that" only as Pure intro (only for single
  3102 steps); the "that" rule assumption may now be involved in implicit
  3103 finishing, thus ".." becomes a feasible for trivial obtains;
  3104 
  3105 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3106 instance proofs may be performed by "..";
  3107 
  3108 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3109 statements as well;
  3110 
  3111 * Pure: more robust selection of calculational rules;
  3112 
  3113 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3114 rule (as well as the assumption rule);
  3115 
  3116 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3117 lemmas, using the graph browser tool;
  3118 
  3119 * Pure: predict failure of "show" in interactive mode;
  3120 
  3121 * Pure: 'thms_containing' now takes actual terms as arguments;
  3122 
  3123 * HOL: improved method 'induct' --- now handles non-atomic goals
  3124 (potential INCOMPATIBILITY); tuned error handling;
  3125 
  3126 * HOL: cases and induct rules now provide explicit hints about the
  3127 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3128 any remaining facts are inserted into the goal verbatim;
  3129 
  3130 * HOL: local contexts (aka cases) may now contain term bindings as
  3131 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3132 the result to be shown in each case;
  3133 
  3134 * HOL: added 'recdef_tc' command;
  3135 
  3136 * isatool convert assists in eliminating legacy ML scripts;
  3137 
  3138 
  3139 *** HOL ***
  3140 
  3141 * HOL/Library: a collection of generic theories to be used together
  3142 with main HOL; the theory loader path already includes this directory
  3143 by default; the following existing theories have been moved here:
  3144 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3145 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3146 
  3147 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3148 modelling and verification task performed in Isabelle/HOL +
  3149 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3150 
  3151 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3152 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3153 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3154 'domain', this makes the theory consistent with mathematical
  3155 literature;
  3156 
  3157 * HOL basics: added overloaded operations "inverse" and "divide"
  3158 (infix "/"), syntax for generic "abs" operation, generic summation
  3159 operator \<Sum>;
  3160 
  3161 * HOL/typedef: simplified package, provide more useful rules (see also
  3162 HOL/subset.thy);
  3163 
  3164 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3165 now expressed as a proper nested rule (old-style tactic scripts may
  3166 require atomize_strip_tac to cope with non-atomic premises);
  3167 
  3168 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3169 to "split_conv" (old name still available for compatibility);
  3170 
  3171 * HOL: improved concrete syntax for strings (e.g. allows translation
  3172 rules with string literals);
  3173 
  3174 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3175  and Fleuriot's mechanization of analysis, including the transcendental
  3176  functions for the reals;
  3177 
  3178 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3179 
  3180 
  3181 *** CTT ***
  3182 
  3183 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3184 "lam" is displayed as TWO lambda-symbols
  3185 
  3186 * CTT: theory Main now available, containing everything (that is, Bool
  3187 and Arith);
  3188 
  3189 
  3190 *** General ***
  3191 
  3192 * Pure: the Simplifier has been implemented properly as a derived rule
  3193 outside of the actual kernel (at last!); the overall performance
  3194 penalty in practical applications is about 50%, while reliability of
  3195 the Isabelle inference kernel has been greatly improved;
  3196 
  3197 * print modes "brackets" and "no_brackets" control output of nested =>
  3198 (types) and ==> (props); the default behaviour is "brackets";
  3199 
  3200 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3201 as assumptions as well;
  3202 
  3203 * system: support Poly/ML 4.0;
  3204 
  3205 * system: isatool install handles KDE version 1 or 2;
  3206 
  3207 
  3208 
  3209 New in Isabelle99-1 (October 2000)
  3210 ----------------------------------
  3211 
  3212 *** Overview of INCOMPATIBILITIES ***
  3213 
  3214 * HOL: simplification of natural numbers is much changed; to partly
  3215 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3216 issue the following ML commands:
  3217 
  3218   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3219   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3220 
  3221 * HOL: simplification no longer dives into case-expressions; this is
  3222 controlled by "t.weak_case_cong" for each datatype t;
  3223 
  3224 * HOL: nat_less_induct renamed to less_induct;
  3225 
  3226 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3227 fixsome to patch .thy and .ML sources automatically;
  3228 
  3229   select_equality  -> some_equality
  3230   select_eq_Ex     -> some_eq_ex
  3231   selectI2EX       -> someI2_ex
  3232   selectI2         -> someI2
  3233   selectI          -> someI
  3234   select1_equality -> some1_equality
  3235   Eps_sym_eq       -> some_sym_eq_trivial
  3236   Eps_eq           -> some_eq_trivial
  3237 
  3238 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3239 
  3240 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3241 instead);
  3242 
  3243 * HOL: the recursion equations generated by 'recdef' are now called
  3244 f.simps instead of f.rules;
  3245 
  3246 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3247 
  3248 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3249 sometimes be needed;
  3250 
  3251 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3252 
  3253 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3254 
  3255 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3256 product is now "<*>" instead of "Times"; the lexicographic product is
  3257 now "<*lex*>" instead of "**";
  3258 
  3259 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3260 of main HOL, but was unused); better use HOL's datatype package;
  3261 
  3262 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3263 the old syntax may be recovered as follows:
  3264 
  3265   syntax (symbols)
  3266     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3267       (infixl "\\<oplus>" 100)
  3268 
  3269 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3270 
  3271 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3272 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3273 internally;
  3274 
  3275 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3276 changed from A/r to A//r;
  3277 
  3278 * ZF: new treatment of arithmetic (nat & int) may break some old
  3279 proofs;
  3280 
  3281 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3282 rulify -> rule_format, elimify -> elim_format, ...);
  3283 
  3284 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3285 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3286 should have to change intro!! to intro? only); replaced "delrule" by
  3287 "rule del";
  3288 
  3289 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3290 
  3291 * Provers: strengthened force_tac by using new first_best_tac;
  3292 
  3293 * LaTeX document preparation: several changes of isabelle.sty (see
  3294 lib/texinputs);
  3295 
  3296 
  3297 *** Document preparation ***
  3298 
  3299 * formal comments (text blocks etc.) in new-style theories may now
  3300 contain antiquotations of thm/prop/term/typ/text to be presented
  3301 according to latex print mode; concrete syntax is like this:
  3302 @{term[show_types] "f(x) = a + x"};
  3303 
  3304 * isatool mkdir provides easy setup of Isabelle session directories,
  3305 including proper document sources;
  3306 
  3307 * generated LaTeX sources are now deleted after successful run
  3308 (isatool document -c); may retain a copy somewhere else via -D option
  3309 of isatool usedir;
  3310 
  3311 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3312 style files, achieving self-contained LaTeX sources and simplifying
  3313 LaTeX debugging;
  3314 
  3315 * old-style theories now produce (crude) LaTeX output as well;
  3316 
  3317 * browser info session directories are now self-contained (may be put
  3318 on WWW server seperately); improved graphs of nested sessions; removed
  3319 graph for 'all sessions';
  3320 
  3321 * several improvements in isabelle style files; \isabellestyle{it}
  3322 produces fake math mode output; \isamarkupheader is now \section by
  3323 default; see lib/texinputs/isabelle.sty etc.;
  3324 
  3325 
  3326 *** Isar ***
  3327 
  3328 * Isar/Pure: local results and corresponding term bindings are now
  3329 subject to Hindley-Milner polymorphism (similar to ML); this
  3330 accommodates incremental type-inference very nicely;
  3331 
  3332 * Isar/Pure: new derived language element 'obtain' supports
  3333 generalized existence reasoning;
  3334 
  3335 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3336 support accumulation of results, without applying any rules yet;
  3337 useful to collect intermediate results without explicit name
  3338 references, and for use with transitivity rules with more than 2
  3339 premises;
  3340 
  3341 * Isar/Pure: scalable support for case-analysis type proofs: new
  3342 'case' language element refers to local contexts symbolically, as
  3343 produced by certain proof methods; internally, case names are attached
  3344 to theorems as "tags";
  3345 
  3346 * Isar/Pure: theory command 'hide' removes declarations from
  3347 class/type/const name spaces;
  3348 
  3349 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3350 indicate potential overloading;
  3351 
  3352 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3353 
  3354 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3355 "{a,b,c}" instead of {a,b,c};
  3356 
  3357 * Isar/Pure now provides its own version of intro/elim/dest
  3358 attributes; useful for building new logics, but beware of confusion
  3359 with the version in Provers/classical;
  3360 
  3361 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3362 case name 'antecedent';
  3363 
  3364 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3365 to the current context is now done automatically);
  3366 
  3367 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3368 for definining proof methods in ML;
  3369 
  3370 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3371 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3372 most cases, one should have to change intro!! to intro? only);
  3373 replaced "delrule" by "rule del";
  3374 
  3375 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3376 'symmetric' attribute (the latter supercedes [RS sym]);
  3377 
  3378 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3379 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3380 well (including splits);
  3381 
  3382 * Isar/Provers: Simplifier and Classical methods now support all kind
  3383 of modifiers used in the past, including 'cong', 'iff', etc.
  3384 
  3385 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3386 of Simplifier and Classical reasoner);
  3387 
  3388 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3389 now support named cases; major packages (inductive, datatype, primrec,
  3390 recdef) support case names and properly name parameters;
  3391 
  3392 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3393 monotonicity conditions are extracted to be proven at end of
  3394 calculations;
  3395 
  3396 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3397 method anyway;
  3398 
  3399 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3400 split_if split_if_asm; datatype package provides theorems foo.splits =
  3401 foo.split foo.split_asm for each datatype;
  3402 
  3403 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3404 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3405 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3406 use "(cases (simplified))" method in proper proof texts);
  3407 
  3408 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3409 
  3410 * Isar: names of theorems etc. may be natural numbers as well;
  3411 
  3412 * Isar: 'pr' command: optional arguments for goals_limit and
  3413 ProofContext.prems_limit; no longer prints theory contexts, but only
  3414 proof states;
  3415 
  3416 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3417 additional print modes to be specified; e.g. "pr(latex)" will print
  3418 proof state according to the Isabelle LaTeX style;
  3419 
  3420 * Isar: improved support for emulating tactic scripts, including proof
  3421 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3422 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3423 (for HOL datatypes);
  3424 
  3425 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3426 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3427 'proof method scripts' have to be in depth-first order;
  3428 
  3429 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3430 
  3431 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3432 should instead use individual commands for printing items
  3433 (print_commands, print_methods etc.);
  3434 
  3435 * Isar: added 'nothing' --- the empty list of theorems;
  3436 
  3437 
  3438 *** HOL ***
  3439 
  3440 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3441 corresponding virtual machine and a specification of its bytecode
  3442 verifier and a lightweight bytecode verifier, including proofs of
  3443 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3444 Cornelia Pusch (see also the homepage of project Bali at
  3445 http://isabelle.in.tum.de/Bali/);
  3446 
  3447 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3448 Clemens Ballarin;
  3449 
  3450 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3451 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3452 Rasmussen;
  3453 
  3454 * HOL/Lattice: fundamental concepts of lattice theory and order
  3455 structures, including duals, properties of bounds versus algebraic
  3456 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3457 Theorem for complete lattices etc.; may also serve as a demonstration
  3458 for abstract algebraic reasoning using axiomatic type classes, and
  3459 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3460 
  3461 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3462 von Oheimb;
  3463 
  3464 * HOL/IMPP: extension of IMP with local variables and mutually
  3465 recursive procedures, by David von Oheimb;
  3466 
  3467 * HOL/Lambda: converted into new-style theory and document;
  3468 
  3469 * HOL/ex/Multiquote: example of multiple nested quotations and
  3470 anti-quotations -- basically a generalized version of de-Bruijn
  3471 representation; very useful in avoiding lifting of operations;
  3472 
  3473 * HOL/record: added general record equality rule to simpset; fixed
  3474 select-update simplification procedure to handle extended records as
  3475 well; admit "r" as field name;
  3476 
  3477 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3478 other numeric types and also as the identity of groups, rings, etc.;
  3479 
  3480 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3481 Types nat and int belong to this axclass;
  3482 
  3483 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3484    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3485    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3486   two terms #m*u and #n*u are replaced by #(m+n)*u
  3487     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3488   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3489     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3490 
  3491 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3492 powerful prover for predicate logic but knows nothing of clasets; see
  3493 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3494 
  3495 * HOL: new version of "case_tac" subsumes both boolean case split and
  3496 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3497 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3498 
  3499 * HOL: simplification no longer dives into case-expressions: only the
  3500 selector expression is simplified, but not the remaining arms; to
  3501 enable full simplification of case-expressions for datatype t, you may
  3502 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3503 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3504 
  3505 * HOL/recdef: the recursion equations generated by 'recdef' for
  3506 function 'f' are now called f.simps instead of f.rules; if all
  3507 termination conditions are proved automatically, these simplification
  3508 rules are added to the simpset, as in primrec; rules may be named
  3509 individually as well, resulting in a separate list of theorems for
  3510 each equation;
  3511 
  3512 * HOL/While is a new theory that provides a while-combinator. It
  3513 permits the definition of tail-recursive functions without the
  3514 provision of a termination measure. The latter is necessary once the
  3515 invariant proof rule for while is applied.
  3516 
  3517 * HOL: new (overloaded) notation for the set of elements below/above
  3518 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3519 
  3520 * HOL: theorems impI, allI, ballI bound as "strip";
  3521 
  3522 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3523 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3524 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3525 
  3526 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3527 
  3528 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3529 main HOL, but was unused);
  3530 
  3531 * HOL: fewer consts declared as global (e.g. have to refer to
  3532 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3533 
  3534 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3535 in case of overlap with user translations (e.g. judgements over
  3536 tuples); (note that the underlying logical represenation is still
  3537 bogus);
  3538 
  3539 
  3540 *** ZF ***
  3541 
  3542 * ZF: simplification automatically cancels common terms in arithmetic
  3543 expressions over nat and int;
  3544 
  3545 * ZF: new treatment of nat to minimize type-checking: all operators
  3546 coerce their operands to a natural number using the function natify,
  3547 making the algebraic laws unconditional;
  3548 
  3549 * ZF: as above, for int: operators coerce their operands to an integer
  3550 using the function intify;
  3551 
  3552 * ZF: the integer library now contains many of the usual laws for the
  3553 orderings, including $<=, and monotonicity laws for $+ and $*;
  3554 
  3555 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3556 simplification;
  3557 
  3558 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3559 to the simplifier and classical reasoner simultaneously;
  3560 
  3561 
  3562 *** General ***
  3563 
  3564 * Provers: blast_tac now handles actual object-logic rules as
  3565 assumptions; note that auto_tac uses blast_tac internally as well;
  3566 
  3567 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3568 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3569 
  3570 * Provers: delrules now handles destruct rules as well (no longer need
  3571 explicit make_elim);
  3572 
  3573 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3574   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3575 use instead the strong form,
  3576   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3577 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3578 from destruct-rules;
  3579 
  3580 * Provers: Simplifier.easy_setup provides a fast path to basic
  3581 Simplifier setup for new object-logics;
  3582 
  3583 * Pure: AST translation rules no longer require constant head on LHS;
  3584 
  3585 * Pure: improved name spaces: ambiguous output is qualified; support
  3586 for hiding of names;
  3587 
  3588 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3589 XSYMBOL_HOME; no longer need to do manual configuration in most
  3590 situations;
  3591 
  3592 * system: compression of ML heaps images may now be controlled via -c
  3593 option of isabelle and isatool usedir (currently only observed by
  3594 Poly/ML);
  3595 
  3596 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3597 useful for remote X11);
  3598 
  3599 * system: provide TAGS file for Isabelle sources;
  3600 
  3601 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3602 order;
  3603 
  3604 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3605 timing flag supersedes proof_timing and Toplevel.trace;
  3606 
  3607 * ML: new combinators |>> and |>>> for incremental transformations
  3608 with secondary results (e.g. certain theory extensions):
  3609 
  3610 * ML: PureThy.add_defs gets additional argument to indicate potential
  3611 overloading (usually false);
  3612 
  3613 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3614 results;
  3615 
  3616 
  3617 
  3618 New in Isabelle99 (October 1999)
  3619 --------------------------------
  3620 
  3621 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3622 
  3623 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3624 are no longer simplified.  (This allows the simplifier to unfold recursive
  3625 functional programs.)  To restore the old behaviour, declare
  3626 
  3627     Delcongs [if_weak_cong];
  3628 
  3629 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3630 complement;
  3631 
  3632 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3633 
  3634 * HOL/datatype: mutual_induct_tac no longer exists --
  3635   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3636 
  3637 * HOL/typedef: fixed type inference for representing set; type
  3638 arguments now have to occur explicitly on the rhs as type constraints;
  3639 
  3640 * ZF: The con_defs part of an inductive definition may no longer refer
  3641 to constants declared in the same theory;
  3642 
  3643 * HOL, ZF: the function mk_cases, generated by the inductive
  3644 definition package, has lost an argument.  To simplify its result, it
  3645 uses the default simpset instead of a supplied list of theorems.
  3646 
  3647 * HOL/List: the constructors of type list are now Nil and Cons;
  3648 
  3649 * Simplifier: the type of the infix ML functions
  3650         setSSolver addSSolver setSolver addSolver
  3651 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  3652 for packaging solvers. A solver is created via
  3653         mk_solver: string -> (thm list -> int -> tactic) -> solver
  3654 where the string argument is only a comment.
  3655 
  3656 
  3657 *** Proof tools ***
  3658 
  3659 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  3660 decision procedure for linear arithmetic. Currently it is used for
  3661 types `nat', `int', and `real' in HOL (see below); it can, should and
  3662 will be instantiated for other types and logics as well.
  3663 
  3664 * The simplifier now accepts rewrite rules with flexible heads, eg
  3665      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  3666   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  3667   matching.
  3668 
  3669 
  3670 *** General ***
  3671 
  3672 * New Isabelle/Isar subsystem provides an alternative to traditional
  3673 tactical theorem proving; together with the ProofGeneral/isar user
  3674 interface it offers an interactive environment for developing human
  3675 readable proof documents (Isar == Intelligible semi-automated
  3676 reasoning); for further information see isatool doc isar-ref,
  3677 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  3678 
  3679 * improved and simplified presentation of theories: better HTML markup
  3680 (including colors), graph views in several sizes; isatool usedir now
  3681 provides a proper interface for user theories (via -P option); actual
  3682 document preparation based on (PDF)LaTeX is available as well (for
  3683 new-style theories only); see isatool doc system for more information;
  3684 
  3685 * native support for Proof General, both for classic Isabelle and
  3686 Isabelle/Isar;
  3687 
  3688 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  3689 using the graph browser tool;
  3690 
  3691 * Isabelle manuals now also available as PDF;
  3692 
  3693 * theory loader rewritten from scratch (may not be fully
  3694 bug-compatible); old loadpath variable has been replaced by show_path,
  3695 add_path, del_path, reset_path functions; new operations such as
  3696 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  3697 isatool doc ref);
  3698 
  3699 * improved isatool install: option -k creates KDE application icon,
  3700 option -p DIR installs standalone binaries;
  3701 
  3702 * added ML_PLATFORM setting (useful for cross-platform installations);
  3703 more robust handling of platform specific ML images for SML/NJ;
  3704 
  3705 * the settings environment is now statically scoped, i.e. it is never
  3706 created again in sub-processes invoked from isabelle, isatool, or
  3707 Isabelle;
  3708 
  3709 * path element specification '~~' refers to '$ISABELLE_HOME';
  3710 
  3711 * in locales, the "assumes" and "defines" parts may be omitted if
  3712 empty;
  3713 
  3714 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  3715 long arrows);
  3716 
  3717 * new print_mode "HTML";
  3718 
  3719 * new flag show_tags controls display of tags of theorems (which are
  3720 basically just comments that may be attached by some tools);
  3721 
  3722 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  3723 mode and goal output format:
  3724 
  3725 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  3726 244c244
  3727 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  3728 ---
  3729 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  3730 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  3731 181c181
  3732 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  3733 ---
  3734 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  3735 
  3736 * function bind_thms stores lists of theorems (cf. bind_thm);
  3737 
  3738 * new shorthand tactics ftac, eatac, datac, fatac;
  3739 
  3740 * qed (and friends) now accept "" as result name; in that case the
  3741 theorem is not stored, but proper checks and presentation of the
  3742 result still apply;
  3743 
  3744 * theorem database now also indexes constants "Trueprop", "all",
  3745 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  3746 
  3747 
  3748 *** HOL ***
  3749 
  3750 ** HOL arithmetic **
  3751 
  3752 * There are now decision procedures for linear arithmetic over nat and
  3753 int:
  3754 
  3755 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  3756 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  3757 are treated as atomic; subformulae not involving type `nat' or `int'
  3758 are ignored; quantified subformulae are ignored unless they are
  3759 positive universal or negative existential. The tactic has to be
  3760 invoked by hand and can be a little bit slow. In particular, the
  3761 running time is exponential in the number of occurrences of `min' and
  3762 `max', and `-' on `nat'.
  3763 
  3764 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  3765 (negated) (in)equalities among the premises and the conclusion into
  3766 account (i.e. no compound formulae) and does not know about `min' and
  3767 `max', and `-' on `nat'. It is fast and is used automatically by the
  3768 simplifier.
  3769 
  3770 NB: At the moment, these decision procedures do not cope with mixed
  3771 nat/int formulae where the two parts interact, such as `m < n ==>
  3772 int(m) < int(n)'.
  3773 
  3774 * HOL/Numeral provides a generic theory of numerals (encoded
  3775 efficiently as bit strings); setup for types nat/int/real is in place;
  3776 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  3777 int, existing theories and proof scripts may require a few additional
  3778 type constraints;
  3779 
  3780 * integer division and remainder can now be performed on constant
  3781 arguments;
  3782 
  3783 * many properties of integer multiplication, division and remainder
  3784 are now available;
  3785 
  3786 * An interface to the Stanford Validity Checker (SVC) is available through the
  3787 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  3788 are proved automatically.  SVC must be installed separately, and its results
  3789 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  3790 invocation of the underlying oracle).  For SVC see
  3791   http://verify.stanford.edu/SVC
  3792 
  3793 * IsaMakefile: the HOL-Real target now builds an actual image;
  3794 
  3795 
  3796 ** HOL misc **
  3797 
  3798 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  3799 (in Isabelle/Isar) -- by Gertrud Bauer;
  3800 
  3801 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  3802 analysis for assembly languages with subtypes;
  3803 
  3804 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  3805 -- avoids syntactic ambiguities and treats state, transition, and
  3806 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  3807 changed syntax and (many) tactics;
  3808 
  3809 * HOL/inductive: Now also handles more general introduction rules such
  3810   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3811   theorems are now maintained within the theory (maintained via the
  3812   "mono" attribute);
  3813 
  3814 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3815   (using function types) such as
  3816 
  3817   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3818 
  3819 * HOL/record: record_simproc (part of the default simpset) takes care
  3820 of selectors applied to updated records; record_split_tac is no longer
  3821 part of the default claset; update_defs may now be removed from the
  3822 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3823 
  3824   claset_ref () := claset() addSWrapper record_split_wrapper;
  3825   Delsimprocs [record_simproc]
  3826 
  3827 * HOL/typedef: fixed type inference for representing set; type
  3828 arguments now have to occur explicitly on the rhs as type constraints;
  3829 
  3830 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3831 names rather than an ML expression;
  3832 
  3833 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3834 supplied later.  Program schemes can be defined, such as
  3835     "While B C s = (if B s then While B C (C s) else s)"
  3836 where the well-founded relation can be chosen after B and C have been given.
  3837 
  3838 * HOL/List: the constructors of type list are now Nil and Cons;
  3839 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3840 course, ML tools referring to List.list.op # etc. have to be adapted;
  3841 
  3842 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3843 disabled by default; run isabelle with option -m HOL to get back to
  3844 the original Gordon/HOL-style output;
  3845 
  3846 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3847 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3848 
  3849 * HOL basic syntax simplified (more orthogonal): all variants of
  3850 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3851 Eps operator is provided as well: "SOME x. P[x]";
  3852 
  3853 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3854 
  3855 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3856 thus available for user theories;
  3857 
  3858 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3859 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3860 time;
  3861 
  3862 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3863 several times and then mp;
  3864 
  3865 
  3866 *** LK ***
  3867 
  3868 * the notation <<...>> is now available as a notation for sequences of
  3869 formulas;
  3870 
  3871 * the simplifier is now installed
  3872 
  3873 * the axiom system has been generalized (thanks to Soren Heilmann)
  3874 
  3875 * the classical reasoner now has a default rule database
  3876 
  3877 
  3878 *** ZF ***
  3879 
  3880 * new primrec section allows primitive recursive functions to be given
  3881 directly (as in HOL) over datatypes and the natural numbers;
  3882 
  3883 * new tactics induct_tac and exhaust_tac for induction (or case
  3884 analysis) over datatypes and the natural numbers;
  3885 
  3886 * the datatype declaration of type T now defines the recursor T_rec;
  3887 
  3888 * simplification automatically does freeness reasoning for datatype
  3889 constructors;
  3890 
  3891 * automatic type-inference, with AddTCs command to insert new
  3892 type-checking rules;
  3893 
  3894 * datatype introduction rules are now added as Safe Introduction rules
  3895 to the claset;
  3896 
  3897 * the syntax "if P then x else y" is now available in addition to
  3898 if(P,x,y);
  3899 
  3900 
  3901 *** Internal programming interfaces ***
  3902 
  3903 * tuned simplifier trace output; new flag debug_simp;
  3904 
  3905 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3906 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3907 
  3908 * AxClass.axclass_tac lost the theory argument;
  3909 
  3910 * tuned current_goals_markers semantics: begin / end goal avoids
  3911 printing empty lines;
  3912 
  3913 * removed prs and prs_fn hook, which was broken because it did not
  3914 include \n in its semantics, forcing writeln to add one
  3915 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3916 string -> unit if you really want to output text without newline;
  3917 
  3918 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3919 plain output, interface builders may have to enable 'isabelle_font'
  3920 mode to get Isabelle font glyphs as before;
  3921 
  3922 * refined token_translation interface; INCOMPATIBILITY: output length
  3923 now of type real instead of int;
  3924 
  3925 * theory loader actions may be traced via new ThyInfo.add_hook
  3926 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3927 your own database of information attached to *whole* theories -- as
  3928 opposed to intra-theory data slots offered via TheoryDataFun;
  3929 
  3930 * proper handling of dangling sort hypotheses (at last!);
  3931 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3932 extra sort hypotheses that can be witnessed from the type signature;
  3933 the force_strip_shyps flag is gone, any remaining shyps are simply
  3934 left in the theorem (with a warning issued by strip_shyps_warning);
  3935 
  3936 
  3937 
  3938 New in Isabelle98-1 (October 1998)
  3939 ----------------------------------
  3940 
  3941 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3942 
  3943 * several changes of automated proof tools;
  3944 
  3945 * HOL: major changes to the inductive and datatype packages, including
  3946 some minor incompatibilities of theory syntax;
  3947 
  3948 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3949 called `inj_on';
  3950 
  3951 * HOL: removed duplicate thms in Arith:
  3952   less_imp_add_less  should be replaced by  trans_less_add1
  3953   le_imp_add_le      should be replaced by  trans_le_add1
  3954 
  3955 * HOL: unary minus is now overloaded (new type constraints may be
  3956 required);
  3957 
  3958 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3959 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3960 now taken as an integer constant.
  3961 
  3962 * Pure: ML function 'theory_of' renamed to 'theory';
  3963 
  3964 
  3965 *** Proof tools ***
  3966 
  3967 * Simplifier:
  3968   1. Asm_full_simp_tac is now more aggressive.
  3969      1. It will sometimes reorient premises if that increases their power to
  3970         simplify.
  3971      2. It does no longer proceed strictly from left to right but may also
  3972         rotate premises to achieve further simplification.
  3973      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3974      old Asm_full_simp_tac in that it does not rotate premises.
  3975   2. The simplifier now knows a little bit about nat-arithmetic.
  3976 
  3977 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3978 allows for selected deletion of wrappers, by introduction of names for
  3979 wrapper functionals.  This implies that addbefore, addSbefore,
  3980 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3981 and that adding two tactics with the same name overwrites the first
  3982 one (emitting a warning).
  3983   type wrapper = (int -> tactic) -> (int -> tactic)
  3984   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3985   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3986   delWrapper, delSWrapper: claset *  string            -> claset
  3987   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3988 
  3989 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3990 semantics; addbefore now affects only the unsafe part of step_tac
  3991 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3992 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3993 by Force_tac;
  3994 
  3995 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3996 compWrapper; added safe wrapper (and access functions for it);
  3997 
  3998 * HOL/split_all_tac is now much faster and fails if there is nothing
  3999 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4000 and the names of the automatically generated variables have changed.
  4001 split_all_tac has moved within claset() from unsafe wrappers to safe
  4002 wrappers, which means that !!-bound variables are split much more
  4003 aggressively, and safe_tac and clarify_tac now split such variables.
  4004 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4005 Note: the same holds for record_split_tac, which does the job of
  4006 split_all_tac for record fields.
  4007 
  4008 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4009 permanently to the default simpset using Addsplits just like
  4010 Addsimps. They can be removed via Delsplits just like
  4011 Delsimps. Lower-case versions are also available.
  4012 
  4013 * HOL/Simplifier: The rule split_if is now part of the default
  4014 simpset. This means that the simplifier will eliminate all occurrences
  4015 of if-then-else in the conclusion of a goal. To prevent this, you can
  4016 either remove split_if completely from the default simpset by
  4017 `Delsplits [split_if]' or remove it in a specific call of the
  4018 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4019 other case splitting rules to/from the default simpset: every datatype
  4020 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4021 t is the name of the datatype).
  4022 
  4023 * Classical reasoner / Simplifier combination: new force_tac (and
  4024 derivatives Force_tac, force) combines rewriting and classical
  4025 reasoning (and whatever other tools) similarly to auto_tac, but is
  4026 aimed to solve the given subgoal completely.
  4027 
  4028 
  4029 *** General ***
  4030 
  4031 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4032 and `goalw': the theory is no longer needed as an explicit argument -
  4033 the current theory context is used; assumptions are no longer returned
  4034 at the ML-level unless one of them starts with ==> or !!; it is
  4035 recommended to convert to these new commands using isatool fixgoal
  4036 (backup your sources first!);
  4037 
  4038 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4039 the current theory context, and 'theory' to lookup stored theories;
  4040 
  4041 * new theory section 'locale' for declaring constants, assumptions and
  4042 definitions that have local scope;
  4043 
  4044 * new theory section 'nonterminals' for purely syntactic types;
  4045 
  4046 * new theory section 'setup' for generic ML setup functions
  4047 (e.g. package initialization);
  4048 
  4049 * the distribution now includes Isabelle icons: see
  4050 lib/logo/isabelle-{small,tiny}.xpm;
  4051 
  4052 * isatool install - install binaries with absolute references to
  4053 ISABELLE_HOME/bin;
  4054 
  4055 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4056 
  4057 * print mode 'emacs' reserved for Isamode;
  4058 
  4059 * support multiple print (ast) translations per constant name;
  4060 
  4061 * theorems involving oracles are now printed with a suffixed [!];
  4062 
  4063 
  4064 *** HOL ***
  4065 
  4066 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4067 
  4068 * HOL/inductive package reorganized and improved: now supports mutual
  4069 definitions such as
  4070 
  4071   inductive EVEN ODD
  4072     intrs
  4073       null "0 : EVEN"
  4074       oddI "n : EVEN ==> Suc n : ODD"
  4075       evenI "n : ODD ==> Suc n : EVEN"
  4076 
  4077 new theorem list "elims" contains an elimination rule for each of the
  4078 recursive sets; inductive definitions now handle disjunctive premises
  4079 correctly (also ZF);
  4080 
  4081 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4082 "mutual_induct" no longer exists - the induction rule is always
  4083 contained in "induct";
  4084 
  4085 
  4086 * HOL/datatype package re-implemented and greatly improved: now
  4087 supports mutually recursive datatypes such as
  4088 
  4089   datatype
  4090     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4091             | SUM ('a aexp) ('a aexp)
  4092             | DIFF ('a aexp) ('a aexp)
  4093             | NUM 'a
  4094   and
  4095     'a bexp = LESS ('a aexp) ('a aexp)
  4096             | AND ('a bexp) ('a bexp)
  4097             | OR ('a bexp) ('a bexp)
  4098 
  4099 as well as indirectly recursive datatypes such as
  4100 
  4101   datatype
  4102     ('a, 'b) term = Var 'a
  4103                   | App 'b ((('a, 'b) term) list)
  4104 
  4105 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4106 induction on mutually / indirectly recursive datatypes.
  4107 
  4108 Primrec equations are now stored in theory and can be accessed via
  4109 <function_name>.simps.
  4110 
  4111 INCOMPATIBILITIES:
  4112 
  4113   - Theories using datatypes must now have theory Datatype as an
  4114     ancestor.
  4115   - The specific <typename>.induct_tac no longer exists - use the
  4116     generic induct_tac instead.
  4117   - natE has been renamed to nat.exhaust - use exhaust_tac
  4118     instead of res_inst_tac ... natE. Note that the variable
  4119     names in nat.exhaust differ from the names in natE, this
  4120     may cause some "fragile" proofs to fail.
  4121   - The theorems split_<typename>_case and split_<typename>_case_asm
  4122     have been renamed to <typename>.split and <typename>.split_asm.
  4123   - Since default sorts of type variables are now handled correctly,
  4124     some datatype definitions may have to be annotated with explicit
  4125     sort constraints.
  4126   - Primrec definitions no longer require function name and type
  4127     of recursive argument.
  4128 
  4129 Consider using isatool fixdatatype to adapt your theories and proof
  4130 scripts to the new package (backup your sources first!).
  4131 
  4132 
  4133 * HOL/record package: considerably improved implementation; now
  4134 includes concrete syntax for record types, terms, updates; theorems
  4135 for surjective pairing and splitting !!-bound record variables; proof
  4136 support is as follows:
  4137 
  4138   1) standard conversions (selectors or updates applied to record
  4139 constructor terms) are part of the standard simpset;
  4140 
  4141   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4142 made part of standard simpset and claset via addIffs;
  4143 
  4144   3) a tactic for record field splitting (record_split_tac) is part of
  4145 the standard claset (addSWrapper);
  4146 
  4147 To get a better idea about these rules you may retrieve them via
  4148 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4149 the name of your record type.
  4150 
  4151 The split tactic 3) conceptually simplifies by the following rule:
  4152 
  4153   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4154 
  4155 Thus any record variable that is bound by meta-all will automatically
  4156 blow up into some record constructor term, consequently the
  4157 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4158 solve record problems automatically.
  4159 
  4160 
  4161 * reorganized the main HOL image: HOL/Integ and String loaded by
  4162 default; theory Main includes everything;
  4163 
  4164 * automatic simplification of integer sums and comparisons, using cancellation;
  4165 
  4166 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4167 
  4168 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4169 
  4170 * many new identities for unions, intersections, set difference, etc.;
  4171 
  4172 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4173 called split_if, split_split, split_sum_case and split_nat_case (to go
  4174 with add/delsplits);
  4175 
  4176 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4177 (?x::unit) = (); this is made part of the default simpset, which COULD
  4178 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4179 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4180 unit_abs_eta_conv is added in order to counter the effect of
  4181 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4182 %u.f();
  4183 
  4184 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4185 makes more sense);
  4186 
  4187 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4188   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4189   disjointness reasoning but breaking a few old proofs.
  4190 
  4191 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4192 to 'converse' from 'inverse' (for compatibility with ZF and some
  4193 literature);
  4194 
  4195 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4196 the well-founded relation;
  4197 
  4198 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4199     Compl A.  The "Compl" syntax remains available as input syntax for this
  4200     release ONLY.
  4201 
  4202 * HOL/Update: new theory of function updates:
  4203     f(a:=b) == %x. if x=a then b else f x
  4204 may also be iterated as in f(a:=b,c:=d,...);
  4205 
  4206 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4207 
  4208 * HOL/List:
  4209   - new function list_update written xs[i:=v] that updates the i-th
  4210     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4211   - new function `upt' written [i..j(] which generates the list
  4212     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4213     bound write [i..j], which is a shorthand for [i..j+1(].
  4214   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4215 
  4216 * HOL/Arith:
  4217   - removed 'pred' (predecessor) function;
  4218   - generalized some theorems about n-1;
  4219   - many new laws about "div" and "mod";
  4220   - new laws about greatest common divisors (see theory ex/Primes);
  4221 
  4222 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4223 instead of "inverse";
  4224 
  4225 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4226   of the multiset ordering;
  4227 
  4228 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4229   (not included by default);
  4230 
  4231 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4232 
  4233 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4234   programs, i.e. different program variables may have different types.
  4235 
  4236 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4237   [previously, this check worked only if the rewrite rule was unconditional]
  4238   Now rew can involve either definitions or equalities (either == or =).
  4239 
  4240 
  4241 *** ZF ***
  4242 
  4243 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4244   only the theorems proved on ZF.ML;
  4245 
  4246 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4247   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4248   disjointness reasoning but breaking a few old proofs.
  4249 
  4250 * ZF/Update: new theory of function updates
  4251     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4252   may also be iterated as in f(a:=b,c:=d,...);
  4253 
  4254 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4255 
  4256 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4257   [previously, this check worked only if the rewrite rule was unconditional]
  4258   Now rew can involve either definitions or equalities (either == or =).
  4259 
  4260 * case_tac provided for compatibility with HOL
  4261     (like the old excluded_middle_tac, but with subgoals swapped)
  4262 
  4263 
  4264 *** Internal programming interfaces ***
  4265 
  4266 * Pure: several new basic modules made available for general use, see
  4267 also src/Pure/README;
  4268 
  4269 * improved the theory data mechanism to support encapsulation (data
  4270 kind name replaced by private Object.kind, acting as authorization
  4271 key); new type-safe user interface via functor TheoryDataFun; generic
  4272 print_data function becomes basically useless;
  4273 
  4274 * removed global_names compatibility flag -- all theory declarations
  4275 are qualified by default;
  4276 
  4277 * module Pure/Syntax now offers quote / antiquote translation
  4278 functions (useful for Hoare logic etc. with implicit dependencies);
  4279 see HOL/ex/Antiquote for an example use;
  4280 
  4281 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4282 cterm -> thm;
  4283 
  4284 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4285 subgoal;
  4286 
  4287 * Display.print_goals function moved to Locale.print_goals;
  4288 
  4289 * standard print function for goals supports current_goals_markers
  4290 variable for marking begin of proof, end of proof, start of goal; the
  4291 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4292 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4293 for example;
  4294 
  4295 
  4296 
  4297 New in Isabelle98 (January 1998)
  4298 --------------------------------
  4299 
  4300 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4301 
  4302 * changed lexical syntax of terms / types: dots made part of long
  4303 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4304 
  4305 * simpset (and claset) reference variable replaced by functions
  4306 simpset / simpset_ref;
  4307 
  4308 * no longer supports theory aliases (via merge) and non-trivial
  4309 implicit merge of thms' signatures;
  4310 
  4311 * most internal names of constants changed due to qualified names;
  4312 
  4313 * changed Pure/Sequence interface (see Pure/seq.ML);
  4314 
  4315 
  4316 *** General Changes ***
  4317 
  4318 * hierachically structured name spaces (for consts, types, axms, thms
  4319 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4320 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4321 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4322 long_names for fully qualified output names; NOTE: ML programs
  4323 (special tactics, packages etc.) referring to internal names may have
  4324 to be adapted to cope with fully qualified names; in case of severe
  4325 backward campatibility problems try setting 'global_names' at compile
  4326 time to have enrything declared within a flat name space; one may also
  4327 fine tune name declarations in theories via the 'global' and 'local'
  4328 section;
  4329 
  4330 * reimplemented the implicit simpset and claset using the new anytype
  4331 data filed in signatures; references simpset:simpset ref etc. are
  4332 replaced by functions simpset:unit->simpset and
  4333 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4334 to patch your ML files accordingly;
  4335 
  4336 * HTML output now includes theory graph data for display with Java
  4337 applet or isatool browser; data generated automatically via isatool
  4338 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4339 
  4340 * defs may now be conditional; improved rewrite_goals_tac to handle
  4341 conditional equations;
  4342 
  4343 * defs now admits additional type arguments, using TYPE('a) syntax;
  4344 
  4345 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4346 creates a new theory node; implicit merge of thms' signatures is
  4347 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4348 transfer:theory->thm->thm in (rare) cases;
  4349 
  4350 * improved handling of draft signatures / theories; draft thms (and
  4351 ctyps, cterms) are automatically promoted to real ones;
  4352 
  4353 * slightly changed interfaces for oracles: admit many per theory, named
  4354 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4355 
  4356 * print_goals: optional output of const types (set show_consts and
  4357 show_types);
  4358 
  4359 * improved output of warnings (###) and errors (***);
  4360 
  4361 * subgoal_tac displays a warning if the new subgoal has type variables;
  4362 
  4363 * removed old README and Makefiles;
  4364 
  4365 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4366 
  4367 * removed obsolete init_pps and init_database;
  4368 
  4369 * deleted the obsolete tactical STATE, which was declared by
  4370     fun STATE tacfun st = tacfun st st;
  4371 
  4372 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4373 (which abbreviates $HOME);
  4374 
  4375 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4376 use isatool fixseq to adapt your ML programs (this works for fully
  4377 qualified references to the Sequence structure only!);
  4378 
  4379 * use_thy no longer requires writable current directory; it always
  4380 reloads .ML *and* .thy file, if either one is out of date;
  4381 
  4382 
  4383 *** Classical Reasoner ***
  4384 
  4385 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4386 tactics that use classical reasoning to simplify a subgoal without
  4387 splitting it into several subgoals;
  4388 
  4389 * Safe_tac: like safe_tac but uses the default claset;
  4390 
  4391 
  4392 *** Simplifier ***
  4393 
  4394 * added simplification meta rules:
  4395     (asm_)(full_)simplify: simpset -> thm -> thm;
  4396 
  4397 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4398 logics (again);
  4399 
  4400 * added prems argument to simplification procedures;
  4401 
  4402 * HOL, FOL, ZF: added infix function `addsplits':
  4403   instead of `<simpset> setloop (split_tac <thms>)'
  4404   you can simply write `<simpset> addsplits <thms>'
  4405 
  4406 
  4407 *** Syntax ***
  4408 
  4409 * TYPE('a) syntax for type reflection terms;
  4410 
  4411 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4412 
  4413 * pretty printer: changed order of mixfix annotation preference (again!);
  4414 
  4415 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4416 
  4417 
  4418 *** HOL ***
  4419 
  4420 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4421   with `addloop' of the simplifier to faciliate case splitting in premises.
  4422 
  4423 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4424 
  4425 * HOL/Auth: new protocol proofs including some for the Internet
  4426   protocol TLS;
  4427 
  4428 * HOL/Map: new theory of `maps' a la VDM;
  4429 
  4430 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4431 cancelling out common nat summands from =, <, <= (in)equalities, or
  4432 differences; simplification procedures nat_cancel_factor for
  4433 cancelling common factor from =, <, <= (in)equalities over natural
  4434 sums; nat_cancel contains both kinds of procedures, it is installed by
  4435 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4436 
  4437 * HOL/simplifier: terms of the form
  4438   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4439   are rewritten to
  4440   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4441   and those of the form
  4442   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4443   are rewritten to
  4444   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4445 
  4446 * HOL/datatype
  4447   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4448 
  4449   P(t_case f1 ... fn x) =
  4450      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4451         ...
  4452        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4453      )
  4454 
  4455   and a theorem `split_t_case_asm' of the form
  4456 
  4457   P(t_case f1 ... fn x) =
  4458     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4459         ...
  4460        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4461      )
  4462   which can be added to a simpset via `addsplits'. The existing theorems
  4463   expand_list_case and expand_option_case have been renamed to
  4464   split_list_case and split_option_case.
  4465 
  4466 * HOL/Arithmetic:
  4467   - `pred n' is automatically converted to `n-1'.
  4468     Users are strongly encouraged not to use `pred' any longer,
  4469     because it will disappear altogether at some point.
  4470   - Users are strongly encouraged to write "0 < n" rather than
  4471     "n ~= 0". Theorems and proof tools have been modified towards this
  4472     `standard'.
  4473 
  4474 * HOL/Lists:
  4475   the function "set_of_list" has been renamed "set" (and its theorems too);
  4476   the function "nth" now takes its arguments in the reverse order and
  4477   has acquired the infix notation "!" as in "xs!n".
  4478 
  4479 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4480 
  4481 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4482   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4483 
  4484 * HOL/record: extensible records with schematic structural subtyping
  4485 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4486 still lacks various theorems and concrete record syntax;
  4487 
  4488 
  4489 *** HOLCF ***
  4490 
  4491 * removed "axioms" and "generated by" sections;
  4492 
  4493 * replaced "ops" section by extended "consts" section, which is capable of
  4494   handling the continuous function space "->" directly;
  4495 
  4496 * domain package:
  4497   . proves theorems immediately and stores them in the theory,
  4498   . creates hierachical name space,
  4499   . now uses normal mixfix annotations (instead of cinfix...),
  4500   . minor changes to some names and values (for consistency),
  4501   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4502   . separator between mutual domain defs: changed "," to "and",
  4503   . improved handling of sort constraints;  now they have to
  4504     appear on the left-hand side of the equations only;
  4505 
  4506 * fixed LAM <x,y,zs>.b syntax;
  4507 
  4508 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4509 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4510 
  4511 
  4512 *** FOL and ZF ***
  4513 
  4514 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4515   with `addloop' of the simplifier to faciliate case splitting in premises.
  4516 
  4517 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4518 in HOL, they strip ALL and --> from proved theorems;
  4519 
  4520 
  4521 
  4522 New in Isabelle94-8 (May 1997)
  4523 ------------------------------
  4524 
  4525 *** General Changes ***
  4526 
  4527 * new utilities to build / run / maintain Isabelle etc. (in parts
  4528 still somewhat experimental); old Makefiles etc. still functional;
  4529 
  4530 * new 'Isabelle System Manual';
  4531 
  4532 * INSTALL text, together with ./configure and ./build scripts;
  4533 
  4534 * reimplemented type inference for greater efficiency, better error
  4535 messages and clean internal interface;
  4536 
  4537 * prlim command for dealing with lots of subgoals (an easier way of
  4538 setting goals_limit);
  4539 
  4540 
  4541 *** Syntax ***
  4542 
  4543 * supports alternative (named) syntax tables (parser and pretty
  4544 printer); internal interface is provided by add_modesyntax(_i);
  4545 
  4546 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4547 be used in conjunction with the Isabelle symbol font; uses the
  4548 "symbols" syntax table;
  4549 
  4550 * added token_translation interface (may translate name tokens in
  4551 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4552 the current print_mode); IMPORTANT: user print translation functions
  4553 are responsible for marking newly introduced bounds
  4554 (Syntax.mark_boundT);
  4555 
  4556 * token translations for modes "xterm" and "xterm_color" that display
  4557 names in bold, underline etc. or colors (which requires a color
  4558 version of xterm);
  4559 
  4560 * infixes may now be declared with names independent of their syntax;
  4561 
  4562 * added typed_print_translation (like print_translation, but may
  4563 access type of constant);
  4564 
  4565 
  4566 *** Classical Reasoner ***
  4567 
  4568 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4569 some limitations.  Blast_tac...
  4570   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4571   + ignores elimination rules that don't have the correct format
  4572         (the conclusion MUST be a formula variable)
  4573   + ignores types, which can make HOL proofs fail
  4574   + rules must not require higher-order unification, e.g. apply_type in ZF
  4575     [message "Function Var's argument not a bound variable" relates to this]
  4576   + its proof strategy is more general but can actually be slower
  4577 
  4578 * substitution with equality assumptions no longer permutes other
  4579 assumptions;
  4580 
  4581 * minor changes in semantics of addafter (now called addaltern); renamed
  4582 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4583 (and access functions for it);
  4584 
  4585 * improved combination of classical reasoner and simplifier:
  4586   + functions for handling clasimpsets
  4587   + improvement of addss: now the simplifier is called _after_ the
  4588     safe steps.
  4589   + safe variant of addss called addSss: uses safe simplifications
  4590     _during_ the safe steps. It is more complete as it allows multiple
  4591     instantiations of unknowns (e.g. with slow_tac).
  4592 
  4593 *** Simplifier ***
  4594 
  4595 * added interface for simplification procedures (functions that
  4596 produce *proven* rewrite rules on the fly, depending on current
  4597 redex);
  4598 
  4599 * ordering on terms as parameter (used for ordered rewriting);
  4600 
  4601 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4602 
  4603 * the solver is now split into a safe and an unsafe part.
  4604 This should be invisible for the normal user, except that the
  4605 functions setsolver and addsolver have been renamed to setSolver and
  4606 addSolver; added safe_asm_full_simp_tac;
  4607 
  4608 
  4609 *** HOL ***
  4610 
  4611 * a generic induction tactic `induct_tac' which works for all datatypes and
  4612 also for type `nat';
  4613 
  4614 * a generic case distinction tactic `exhaust_tac' which works for all
  4615 datatypes and also for type `nat';
  4616 
  4617 * each datatype comes with a function `size';
  4618 
  4619 * patterns in case expressions allow tuple patterns as arguments to
  4620 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4621 
  4622 * primrec now also works with type nat;
  4623 
  4624 * recdef: a new declaration form, allows general recursive functions to be
  4625 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4626 
  4627 * the constant for negation has been renamed from "not" to "Not" to
  4628 harmonize with FOL, ZF, LK, etc.;
  4629 
  4630 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4631 infinite lists;
  4632 
  4633 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4634 
  4635 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4636 problems in commutative rings, using axiomatic type classes for + and *;
  4637 
  4638 * more examples in HOL/MiniML and HOL/Auth;
  4639 
  4640 * more default rewrite rules for quantifiers, union/intersection;
  4641 
  4642 * a new constant `arbitrary == @x.False';
  4643 
  4644 * HOLCF/IOA replaces old HOL/IOA;
  4645 
  4646 * HOLCF changes: derived all rules and arities
  4647   + axiomatic type classes instead of classes
  4648   + typedef instead of faking type definitions
  4649   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  4650   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  4651   + eliminated the types void, one, tr
  4652   + use unit lift and bool lift (with translations) instead of one and tr
  4653   + eliminated blift from Lift3.thy (use Def instead of blift)
  4654   all eliminated rules are derived as theorems --> no visible changes ;
  4655 
  4656 
  4657 *** ZF ***
  4658 
  4659 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  4660 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  4661 as ZF_cs addSIs [equalityI];
  4662 
  4663 
  4664 
  4665 New in Isabelle94-7 (November 96)
  4666 ---------------------------------
  4667 
  4668 * allowing negative levels (as offsets) in prlev and choplev;
  4669 
  4670 * super-linear speedup for large simplifications;
  4671 
  4672 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  4673 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  4674 FAIL); can suppress it using the command Delsimps (ex_simps @
  4675 all_simps); De Morgan laws are also now included, by default;
  4676 
  4677 * improved printing of ==>  :  ~:
  4678 
  4679 * new object-logic "Sequents" adds linear logic, while replacing LK
  4680 and Modal (thanks to Sara Kalvala);
  4681 
  4682 * HOL/Auth: correctness proofs for authentication protocols;
  4683 
  4684 * HOL: new auto_tac combines rewriting and classical reasoning (many
  4685 examples on HOL/Auth);
  4686 
  4687 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  4688 the rewriter and classical reasoner simultaneously;
  4689 
  4690 * function uresult no longer returns theorems in "standard" format;
  4691 regain previous version by: val uresult = standard o uresult;
  4692 
  4693 
  4694 
  4695 New in Isabelle94-6
  4696 -------------------
  4697 
  4698 * oracles -- these establish an interface between Isabelle and trusted
  4699 external reasoners, which may deliver results as theorems;
  4700 
  4701 * proof objects (in particular record all uses of oracles);
  4702 
  4703 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  4704 
  4705 * "constdefs" section in theory files;
  4706 
  4707 * "primrec" section (HOL) no longer requires names;
  4708 
  4709 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  4710 
  4711 
  4712 
  4713 New in Isabelle94-5
  4714 -------------------
  4715 
  4716 * reduced space requirements;
  4717 
  4718 * automatic HTML generation from theories;
  4719 
  4720 * theory files no longer require "..." (quotes) around most types;
  4721 
  4722 * new examples, including two proofs of the Church-Rosser theorem;
  4723 
  4724 * non-curried (1994) version of HOL is no longer distributed;
  4725 
  4726 
  4727 
  4728 New in Isabelle94-4
  4729 -------------------
  4730 
  4731 * greatly reduced space requirements;
  4732 
  4733 * theory files (.thy) no longer require \...\ escapes at line breaks;
  4734 
  4735 * searchable theorem database (see the section "Retrieving theorems" on
  4736 page 8 of the Reference Manual);
  4737 
  4738 * new examples, including Grabczewski's monumental case study of the
  4739 Axiom of Choice;
  4740 
  4741 * The previous version of HOL renamed to Old_HOL;
  4742 
  4743 * The new version of HOL (previously called CHOL) uses a curried syntax
  4744 for functions.  Application looks like f a b instead of f(a,b);
  4745 
  4746 * Mutually recursive inductive definitions finally work in HOL;
  4747 
  4748 * In ZF, pattern-matching on tuples is now available in all abstractions and
  4749 translates to the operator "split";
  4750 
  4751 
  4752 
  4753 New in Isabelle94-3
  4754 -------------------
  4755 
  4756 * new infix operator, addss, allowing the classical reasoner to
  4757 perform simplification at each step of its search.  Example:
  4758         fast_tac (cs addss ss)
  4759 
  4760 * a new logic, CHOL, the same as HOL, but with a curried syntax
  4761 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  4762 look like (a,b) instead of <a,b>;
  4763 
  4764 * PLEASE NOTE: CHOL will eventually replace HOL!
  4765 
  4766 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  4767 It translates to the operator "split".  A new theory of integers is available;
  4768 
  4769 * In ZF, integer numerals now denote two's-complement binary integers.
  4770 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  4771 
  4772 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  4773 of the Axiom of Choice;
  4774 
  4775 
  4776 
  4777 New in Isabelle94-2
  4778 -------------------
  4779 
  4780 * Significantly faster resolution;
  4781 
  4782 * the different sections in a .thy file can now be mixed and repeated
  4783 freely;
  4784 
  4785 * Database of theorems for FOL, HOL and ZF.  New
  4786 commands including qed, qed_goal and bind_thm store theorems in the database.
  4787 
  4788 * Simple database queries: return a named theorem (get_thm) or all theorems of
  4789 a given theory (thms_of), or find out what theory a theorem was proved in
  4790 (theory_of_thm);
  4791 
  4792 * Bugs fixed in the inductive definition and datatype packages;
  4793 
  4794 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  4795 and HOL_dup_cs obsolete;
  4796 
  4797 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  4798 have been removed;
  4799 
  4800 * Simpler definition of function space in ZF;
  4801 
  4802 * new results about cardinal and ordinal arithmetic in ZF;
  4803 
  4804 * 'subtype' facility in HOL for introducing new types as subsets of existing
  4805 types;
  4806 
  4807 
  4808 $Id$