NEWS
author haftmann
Fri Jan 25 14:54:44 2008 +0100 (2008-01-25)
changeset 25966 74f6817870f9
parent 25961 ec39d7e40554
child 25970 9053fd546501
permissions -rw-r--r--
dropped superfluous code theorems
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Syntax: symbol \<chi> is now considered a letter.  Potential
    10 INCOMPATIBILITY in identifier syntax etc.
    11 
    12 * Outer syntax: string tokens may contain arbitrary character codes
    13 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
    14 "foo_bar".
    15 
    16 
    17 *** Pure ***
    18 
    19 * Instantiation target allows for simultaneous specification of class instance
    20 operations together with an instantiation proof.  Type check phase allows to
    21 refer to class operations uniformly.  See HOL/Complex/Complex.thy for an Isar
    22 example and HOL/Library/Eval.thy for an ML example.
    23 Superseedes some immature attempts.
    24 
    25 
    26 *** HOL ***
    27 
    28 * Theorems "power.simps" renamed to "power_int.simps".
    29 
    30 * New class semiring_div provides basic abstract properties of semirings
    31 with division and modulo operations.  Subsumes former class dvd_mod.
    32 
    33 * Merged theories IntDef, Numeral and IntArith into unified theory Int.
    34 INCOMPATIBILITY.
    35 
    36 * Theory Library/Code_Index: type "index" now represents natural numbers rather
    37 than integers.  INCOMPATIBILITY.
    38 
    39 * New class "uminus" with operation "uminus" (split of from class "minus"
    40 which now only has operation "minus", binary).  INCOMPATIBILITY.
    41 
    42 * New primrec package.  Specification syntax conforms in style to
    43 definition/function/....  No separate induction rule is provided.
    44 The "primrec" command distinguishes old-style and new-style specifications
    45 by syntax.  The former primrec package is now named OldPrimrecPackage.
    46 When adjusting theories, beware: constants stemming for new-style
    47 primrec specifications have authentic syntax.
    48 
    49 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
    50 
    51 * Library/ListSpace: new theory of arithmetic vector operations.
    52 
    53 * Constants "card", "internal_split", "option_map" now with authentic
    54 syntax.  INCOMPATIBILITY.
    55 
    56 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
    57 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
    58 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
    59 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
    60 Sup_set_def, le_def, less_def, option_map_def now with object
    61 equality.  INCOMPATIBILITY.
    62 
    63 * New method "induction_scheme" derives user-specified induction rules
    64 from wellfounded induction and completeness of patterns. This factors
    65 out some operations that are done internally by the function package
    66 and makes them available separately. See "HOL/ex/Induction_Scheme.thy"
    67 for examples,
    68 
    69 * Records. Removed K_record, and replaced it by pure lambda term
    70 %x. c. The simplifier setup is now more robust against eta expansion.
    71 INCOMPATIBILITY: in cases explicitly referring to K_record.
    72 
    73 * Metis prover is now an order of magnitude faster, and also works
    74 with multithreading.
    75 
    76 
    77 *** ML ***
    78 
    79 * The ``print mode'' is now a thread-local value derived from a global
    80 template (the former print_mode reference), thus access becomes
    81 non-critical.  The global print_mode reference is for session
    82 management only; user-code should use print_mode_value,
    83 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
    84 
    85 
    86 *** System ***
    87 
    88 * Multithreading.max_threads := 0 refers to the number of actual CPU
    89 cores of the underlying machine, which is a good starting point for
    90 optimal performance tuning.  The corresponding usedir option -M allows
    91 "max" as an alias for "0".  WARNING: does not work on certain versions
    92 of Mac OS (with Poly/ML 5.1).
    93 
    94 * isatool tty runs Isabelle process with plain tty interaction;
    95 optional line editor may be specified via ISABELLE_LINE_EDITOR
    96 setting, the default settings attempt to locate "ledit" and "rlwrap".
    97 
    98 * isatool browser now works with Cygwin as well, using general
    99 "javapath" function defined in Isabelle process environment.
   100 
   101 * isabelle-process: non-ML sessions are run with "nice", to prevent
   102 Isabelle from flooding interactive front-ends (notably ProofGeneral /
   103 XEmacs).
   104 
   105 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   106 provides general wrapper for managing an Isabelle process in a robust
   107 fashion, with ``cooked'' output from stdin/stderr.
   108 
   109 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   110 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   111 
   112 
   113 
   114 New in Isabelle2007 (November 2007)
   115 -----------------------------------
   116 
   117 *** General ***
   118 
   119 * More uniform information about legacy features, notably a
   120 warning/error of "Legacy feature: ...", depending on the state of the
   121 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   122 legacy features will disappear eventually.
   123 
   124 * Theory syntax: the header format ``theory A = B + C:'' has been
   125 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   126 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   127 
   128 * Theory syntax: the old non-Isar theory file format has been
   129 discontinued altogether.  Note that ML proof scripts may still be used
   130 with Isar theories; migration is usually quite simple with the ML
   131 function use_legacy_bindings.  INCOMPATIBILITY.
   132 
   133 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   134 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   135 quotes.
   136 
   137 * Theory loader: be more serious about observing the static theory
   138 header specifications (including optional directories), but not the
   139 accidental file locations of previously successful loads.  The strict
   140 update policy of former update_thy is now already performed by
   141 use_thy, so the former has been removed; use_thys updates several
   142 theories simultaneously, just as 'imports' within a theory header
   143 specification, but without merging the results.  Potential
   144 INCOMPATIBILITY: may need to refine theory headers and commands
   145 ROOT.ML which depend on load order.
   146 
   147 * Theory loader: optional support for content-based file
   148 identification, instead of the traditional scheme of full physical
   149 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   150 (cf. the system manual).  The new scheme allows to work with
   151 non-finished theories in persistent session images, such that source
   152 files may be moved later on without requiring reloads.
   153 
   154 * Theory loader: old-style ML proof scripts being *attached* to a thy
   155 file (with the same base name as the theory) are considered a legacy
   156 feature, which will disappear eventually. Even now, the theory loader
   157 no longer maintains dependencies on such files.
   158 
   159 * Syntax: the scope for resolving ambiguities via type-inference is
   160 now limited to individual terms, instead of whole simultaneous
   161 specifications as before. This greatly reduces the complexity of the
   162 syntax module and improves flexibility by separating parsing and
   163 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   164 'fixes' etc.) are required in rare situations.
   165 
   166 * Syntax: constants introduced by new-style packages ('definition',
   167 'abbreviation' etc.) are passed through the syntax module in
   168 ``authentic mode''. This means that associated mixfix annotations
   169 really stick to such constants, independently of potential name space
   170 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   171 trees are represented slightly differently, may need to adapt syntax
   172 translations accordingly. Use CONST marker in 'translations' and
   173 @{const_syntax} antiquotation in 'parse_translation' etc.
   174 
   175 * Legacy goal package: reduced interface to the bare minimum required
   176 to keep existing proof scripts running.  Most other user-level
   177 functions are now part of the OldGoals structure, which is *not* open
   178 by default (consider isatool expandshort before open OldGoals).
   179 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   180 these tend to cause confusion about the actual goal (!) context being
   181 used here, which is not necessarily the same as the_context().
   182 
   183 * Command 'find_theorems': supports "*" wild-card in "name:"
   184 criterion; "with_dups" option.  Certain ProofGeneral versions might
   185 support a specific search form (see ProofGeneral/CHANGES).
   186 
   187 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   188 by default, which means that "prems" (and also "fixed variables") are
   189 suppressed from proof state output.  Note that the ProofGeneral
   190 settings mechanism allows to change and save options persistently, but
   191 older versions of Isabelle will fail to start up if a negative prems
   192 limit is imposed.
   193 
   194 * Local theory targets may be specified by non-nested blocks of
   195 ``context/locale/class ... begin'' followed by ``end''.  The body may
   196 contain definitions, theorems etc., including any derived mechanism
   197 that has been implemented on top of these primitives.  This concept
   198 generalizes the existing ``theorem (in ...)'' towards more versatility
   199 and scalability.
   200 
   201 * Proof General interface: proper undo of final 'end' command;
   202 discontinued Isabelle/classic mode (ML proof scripts).
   203 
   204 
   205 *** Document preparation ***
   206 
   207 * Added antiquotation @{theory name} which prints the given name,
   208 after checking that it refers to a valid ancestor theory in the
   209 current context.
   210 
   211 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   212 check the given source text as ML type/structure, printing verbatim.
   213 
   214 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   215 "c args == rhs" given in the current context.  (Any number of
   216 arguments may be given on the LHS.)
   217 
   218 
   219 *** Pure ***
   220 
   221 * The 'class' package offers a combination of axclass and locale to
   222 achieve Haskell-like type classes in Isabelle.  Definitions and
   223 theorems within a class context produce both relative results (with
   224 implicit parameters according to the locale context), and polymorphic
   225 constants with qualified polymorphism (according to the class
   226 context).  Within the body context of a 'class' target, a separate
   227 syntax layer ("user space type system") takes care of converting
   228 between global polymorphic consts and internal locale representation.
   229 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   230 "isatool doc classes" provides a tutorial.
   231 
   232 * Generic code generator framework allows to generate executable
   233 code for ML and Haskell (including Isabelle classes).  A short usage
   234 sketch:
   235 
   236     internal compilation:
   237         export_code <list of constants (term syntax)> in SML
   238     writing SML code to a file:
   239         export_code <list of constants (term syntax)> in SML <filename>
   240     writing OCaml code to a file:
   241         export_code <list of constants (term syntax)> in OCaml <filename>
   242     writing Haskell code to a bunch of files:
   243         export_code <list of constants (term syntax)> in Haskell <filename>
   244 
   245     evaluating closed propositions to True/False using code generation:
   246         method ``eval''
   247 
   248 Reasonable default setup of framework in HOL.
   249 
   250 Theorem attributs for selecting and transforming function equations theorems:
   251 
   252     [code fun]:        select a theorem as function equation for a specific constant
   253     [code fun del]:    deselect a theorem as function equation for a specific constant
   254     [code inline]:     select an equation theorem for unfolding (inlining) in place
   255     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   256 
   257 User-defined serializations (target in {SML, OCaml, Haskell}):
   258 
   259     code_const <and-list of constants (term syntax)>
   260       {(target) <and-list of const target syntax>}+
   261 
   262     code_type <and-list of type constructors>
   263       {(target) <and-list of type target syntax>}+
   264 
   265     code_instance <and-list of instances>
   266       {(target)}+
   267         where instance ::= <type constructor> :: <class>
   268 
   269     code_class <and_list of classes>
   270       {(target) <and-list of class target syntax>}+
   271         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   272 
   273 code_instance and code_class only are effective to target Haskell.
   274 
   275 For example usage see src/HOL/ex/Codegenerator.thy and
   276 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   277 generation from Isabelle/HOL theories is available via "isatool doc
   278 codegen".
   279 
   280 * Code generator: consts in 'consts_code' Isar commands are now
   281 referred to by usual term syntax (including optional type
   282 annotations).
   283 
   284 * Command 'no_translations' removes translation rules from theory
   285 syntax.
   286 
   287 * Overloaded definitions are now actually checked for acyclic
   288 dependencies.  The overloading scheme is slightly more general than
   289 that of Haskell98, although Isabelle does not demand an exact
   290 correspondence to type class and instance declarations.
   291 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   292 exotic versions of overloading -- at the discretion of the user!
   293 
   294 Polymorphic constants are represented via type arguments, i.e. the
   295 instantiation that matches an instance against the most general
   296 declaration given in the signature.  For example, with the declaration
   297 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   298 as c(nat).  Overloading is essentially simultaneous structural
   299 recursion over such type arguments.  Incomplete specification patterns
   300 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   301 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   302 Command 'print_theory' outputs the normalized system of recursive
   303 equations, see section "definitions".
   304 
   305 * Configuration options are maintained within the theory or proof
   306 context (with name and type bool/int/string), providing a very simple
   307 interface to a poor-man's version of general context data.  Tools may
   308 declare options in ML (e.g. using Attrib.config_int) and then refer to
   309 these values using Config.get etc.  Users may change options via an
   310 associated attribute of the same name.  This form of context
   311 declaration works particularly well with commands 'declare' or
   312 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   313 very easy to avoid global references, which would not observe Isar
   314 toplevel undo/redo and fail to work with multithreading.
   315 
   316 Various global ML references of Pure and HOL have been turned into
   317 configuration options:
   318 
   319   Unify.search_bound		unify_search_bound
   320   Unify.trace_bound		unify_trace_bound
   321   Unify.trace_simp		unify_trace_simp
   322   Unify.trace_types		unify_trace_types
   323   Simplifier.simp_depth_limit	simp_depth_limit
   324   Blast.depth_limit		blast_depth_limit
   325   DatatypeProp.dtK		datatype_distinctness_limit
   326   fast_arith_neq_limit  	fast_arith_neq_limit
   327   fast_arith_split_limit	fast_arith_split_limit
   328 
   329 * Named collections of theorems may be easily installed as context
   330 data using the functor NamedThmsFun (see also
   331 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   332 attributes; there is also a toplevel print command.  This facility is
   333 just a common case of general context data, which is the preferred way
   334 for anything more complex than just a list of facts in canonical
   335 order.
   336 
   337 * Isar: command 'declaration' augments a local theory by generic
   338 declaration functions written in ML.  This enables arbitrary content
   339 being added to the context, depending on a morphism that tells the
   340 difference of the original declaration context wrt. the application
   341 context encountered later on.
   342 
   343 * Isar: proper interfaces for simplification procedures.  Command
   344 'simproc_setup' declares named simprocs (with match patterns, and body
   345 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   346 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   347 
   348 * Isar: an extra pair of brackets around attribute declarations
   349 abbreviates a theorem reference involving an internal dummy fact,
   350 which will be ignored later --- only the effect of the attribute on
   351 the background context will persist.  This form of in-place
   352 declarations is particularly useful with commands like 'declare' and
   353 'using', for example ``have A using [[simproc a]] by simp''.
   354 
   355 * Isar: method "assumption" (and implicit closing of subproofs) now
   356 takes simple non-atomic goal assumptions into account: after applying
   357 an assumption as a rule the resulting subgoals are solved by atomic
   358 assumption steps.  This is particularly useful to finish 'obtain'
   359 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   360 without referring to the original premise "!!x. P x ==> thesis" in the
   361 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   362 more permissive.
   363 
   364 * Isar: implicit use of prems from the Isar proof context is
   365 considered a legacy feature.  Common applications like ``have A .''
   366 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   367 referencing facts explicitly here improves readability and
   368 maintainability of proof texts.
   369 
   370 * Isar: improper proof element 'guess' is like 'obtain', but derives
   371 the obtained context from the course of reasoning!  For example:
   372 
   373   assume "EX x y. A x & B y"   -- "any previous fact"
   374   then guess x and y by clarify
   375 
   376 This technique is potentially adventurous, depending on the facts and
   377 proof tools being involved here.
   378 
   379 * Isar: known facts from the proof context may be specified as literal
   380 propositions, using ASCII back-quote syntax.  This works wherever
   381 named facts used to be allowed so far, in proof commands, proof
   382 methods, attributes etc.  Literal facts are retrieved from the context
   383 according to unification of type and term parameters.  For example,
   384 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   385 theorems in the current context, then these are valid literal facts:
   386 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   387 
   388 There is also a proof method "fact" which does the same composition
   389 for explicit goal states, e.g. the following proof texts coincide with
   390 certain special cases of literal facts:
   391 
   392   have "A" by fact                 ==  note `A`
   393   have "A ==> B" by fact           ==  note `A ==> B`
   394   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   395   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   396 
   397 * Isar: ":" (colon) is no longer a symbolic identifier character in
   398 outer syntax.  Thus symbolic identifiers may be used without
   399 additional white space in declarations like this: ``assume *: A''.
   400 
   401 * Isar: 'print_facts' prints all local facts of the current context,
   402 both named and unnamed ones.
   403 
   404 * Isar: 'def' now admits simultaneous definitions, e.g.:
   405 
   406   def x == "t" and y == "u"
   407 
   408 * Isar: added command 'unfolding', which is structurally similar to
   409 'using', but affects both the goal state and facts by unfolding given
   410 rewrite rules.  Thus many occurrences of the 'unfold' method or
   411 'unfolded' attribute may be replaced by first-class proof text.
   412 
   413 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   414 and command 'unfolding' now all support object-level equalities
   415 (potentially conditional).  The underlying notion of rewrite rule is
   416 analogous to the 'rule_format' attribute, but *not* that of the
   417 Simplifier (which is usually more generous).
   418 
   419 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   420 premises of a theorem by n. Useful in conjunction with drule.
   421 
   422 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   423 method expression within a sandbox consisting of the first N
   424 sub-goals, which need to exist.  For example, ``simp_all [3]''
   425 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   426 simplifies all new goals that emerge from applying rule foo to the
   427 originally first one.
   428 
   429 * Isar: schematic goals are no longer restricted to higher-order
   430 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   431 expected.
   432 
   433 * Isar: the conclusion of a long theorem statement is now either
   434 'shows' (a simultaneous conjunction, as before), or 'obtains'
   435 (essentially a disjunction of cases with local parameters and
   436 assumptions).  The latter allows to express general elimination rules
   437 adequately; in this notation common elimination rules look like this:
   438 
   439   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   440     assumes "EX x. P x"
   441     obtains x where "P x"
   442 
   443   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   444     assumes "A & B"
   445     obtains A and B
   446 
   447   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
   448     assumes "A | B"
   449     obtains
   450       A
   451     | B
   452 
   453 The subsequent classical rules even refer to the formal "thesis"
   454 explicitly:
   455 
   456   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
   457     obtains "~ thesis"
   458 
   459   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
   460     obtains "thesis ==> something"
   461 
   462 The actual proof of an 'obtains' statement is analogous to that of the
   463 Isar proof element 'obtain', only that there may be several cases.
   464 Optional case names may be specified in parentheses; these will be
   465 available both in the present proof and as annotations in the
   466 resulting rule, for later use with the 'cases' method (cf. attribute
   467 case_names).
   468 
   469 * Isar: the assumptions of a long theorem statement are available as
   470 "assms" fact in the proof context.  This is more appropriate than the
   471 (historical) "prems", which refers to all assumptions of the current
   472 context, including those from the target locale, proof body etc.
   473 
   474 * Isar: 'print_statement' prints theorems from the current theory or
   475 proof context in long statement form, according to the syntax of a
   476 top-level lemma.
   477 
   478 * Isar: 'obtain' takes an optional case name for the local context
   479 introduction rule (default "that").
   480 
   481 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
   482 explicit (is "_ ==> ?foo") in the rare cases where this still happens
   483 to occur.
   484 
   485 * Pure: syntax "CONST name" produces a fully internalized constant
   486 according to the current context.  This is particularly useful for
   487 syntax translations that should refer to internal constant
   488 representations independently of name spaces.
   489 
   490 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
   491 instead of "FOO ". This allows multiple binder declarations to coexist
   492 in the same context.  INCOMPATIBILITY.
   493 
   494 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
   495 primitive that also works in a locale context (both for constants and
   496 fixed variables). Type declaration and internal syntactic representation
   497 of given constants retrieved from the context. Likewise, the
   498 'no_notation' command allows to remove given syntax annotations from the
   499 current context.
   500 
   501 * Isar/locales: new derived specification elements 'axiomatization',
   502 'definition', 'abbreviation', which support type-inference, admit
   503 object-level specifications (equality, equivalence).  See also the
   504 isar-ref manual.  Examples:
   505 
   506   axiomatization
   507     eq  (infix "===" 50) where
   508     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
   509 
   510   definition "f x y = x + y + 1"
   511   definition g where "g x = f x x"
   512 
   513   abbreviation
   514     neq  (infix "=!=" 50) where
   515     "x =!= y == ~ (x === y)"
   516 
   517 These specifications may be also used in a locale context.  Then the
   518 constants being introduced depend on certain fixed parameters, and the
   519 constant name is qualified by the locale base name.  An internal
   520 abbreviation takes care for convenient input and output, making the
   521 parameters implicit and using the original short name.  See also
   522 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
   523 entities from a monomorphic theory.
   524 
   525 Presently, abbreviations are only available 'in' a target locale, but
   526 not inherited by general import expressions.  Also note that
   527 'abbreviation' may be used as a type-safe replacement for 'syntax' +
   528 'translations' in common applications.  The "no_abbrevs" print mode
   529 prevents folding of abbreviations in term output.
   530 
   531 Concrete syntax is attached to specified constants in internal form,
   532 independently of name spaces.  The parse tree representation is
   533 slightly different -- use 'notation' instead of raw 'syntax', and
   534 'translations' with explicit "CONST" markup to accommodate this.
   535 
   536 * Pure/Isar: unified syntax for new-style specification mechanisms
   537 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
   538 full type inference and dummy patterns ("_").  For example:
   539 
   540   definition "K x _ = x"
   541 
   542   inductive conj for A B
   543   where "A ==> B ==> conj A B"
   544 
   545 * Pure: command 'print_abbrevs' prints all constant abbreviations of
   546 the current context.  Print mode "no_abbrevs" prevents inversion of
   547 abbreviations on output.
   548 
   549 * Isar/locales: improved parameter handling: use of locales "var" and
   550 "struct" no longer necessary; - parameter renamings are no longer
   551 required to be injective.  For example, this allows to define
   552 endomorphisms as locale endom = homom mult mult h.
   553 
   554 * Isar/locales: changed the way locales with predicates are defined.
   555 Instead of accumulating the specification, the imported expression is
   556 now an interpretation.  INCOMPATIBILITY: different normal form of
   557 locale expressions.  In particular, in interpretations of locales with
   558 predicates, goals repesenting already interpreted fragments are not
   559 removed automatically.  Use methods `intro_locales' and
   560 `unfold_locales'; see below.
   561 
   562 * Isar/locales: new methods `intro_locales' and `unfold_locales'
   563 provide backward reasoning on locales predicates.  The methods are
   564 aware of interpretations and discharge corresponding goals.
   565 `intro_locales' is less aggressive then `unfold_locales' and does not
   566 unfold predicates to assumptions.
   567 
   568 * Isar/locales: the order in which locale fragments are accumulated
   569 has changed.  This enables to override declarations from fragments due
   570 to interpretations -- for example, unwanted simp rules.
   571 
   572 * Isar/locales: interpretation in theories and proof contexts has been
   573 extended.  One may now specify (and prove) equations, which are
   574 unfolded in interpreted theorems.  This is useful for replacing
   575 defined concepts (constants depending on locale parameters) by
   576 concepts already existing in the target context.  Example:
   577 
   578   interpretation partial_order ["op <= :: [int, int] => bool"]
   579     where "partial_order.less (op <=) (x::int) y = (x < y)"
   580 
   581 Typically, the constant `partial_order.less' is created by a
   582 definition specification element in the context of locale
   583 partial_order.
   584 
   585 * Method "induct": improved internal context management to support
   586 local fixes and defines on-the-fly. Thus explicit meta-level
   587 connectives !!  and ==> are rarely required anymore in inductive goals
   588 (using object-logic connectives for this purpose has been long
   589 obsolete anyway). Common proof patterns are explained in
   590 src/HOL/Induct/Common_Patterns.thy, see also
   591 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
   592 examples.
   593 
   594 * Method "induct": improved handling of simultaneous goals. Instead of
   595 introducing object-level conjunction, the statement is now split into
   596 several conclusions, while the corresponding symbolic cases are nested
   597 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
   598 see src/HOL/Induct/Common_Patterns.thy, for example.
   599 
   600 * Method "induct": mutual induction rules are now specified as a list
   601 of rule sharing the same induction cases. HOL packages usually provide
   602 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
   603 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
   604 mutual induction rules differently, i.e. like this:
   605 
   606   (induct rule: foo_bar.inducts)
   607   (induct set: foo bar)
   608   (induct pred: foo bar)
   609   (induct type: foo bar)
   610 
   611 The ML function ProjectRule.projections turns old-style rules into the
   612 new format.
   613 
   614 * Method "coinduct": dual of induction, see
   615 src/HOL/Library/Coinductive_List.thy for various examples.
   616 
   617 * Method "cases", "induct", "coinduct": the ``(open)'' option is
   618 considered a legacy feature.
   619 
   620 * Attribute "symmetric" produces result with standardized schematic
   621 variables (index 0).  Potential INCOMPATIBILITY.
   622 
   623 * Simplifier: by default the simplifier trace only shows top level
   624 rewrites now. That is, trace_simp_depth_limit is set to 1 by
   625 default. Thus there is less danger of being flooded by the trace. The
   626 trace indicates where parts have been suppressed.
   627   
   628 * Provers/classical: removed obsolete classical version of elim_format
   629 attribute; classical elim/dest rules are now treated uniformly when
   630 manipulating the claset.
   631 
   632 * Provers/classical: stricter checks to ensure that supplied intro,
   633 dest and elim rules are well-formed; dest and elim rules must have at
   634 least one premise.
   635 
   636 * Provers/classical: attributes dest/elim/intro take an optional
   637 weight argument for the rule (just as the Pure versions).  Weights are
   638 ignored by automated tools, but determine the search order of single
   639 rule steps.
   640 
   641 * Syntax: input syntax now supports dummy variable binding "%_. b",
   642 where the body does not mention the bound variable.  Note that dummy
   643 patterns implicitly depend on their context of bounds, which makes
   644 "{_. _}" match any set comprehension as expected.  Potential
   645 INCOMPATIBILITY -- parse translations need to cope with syntactic
   646 constant "_idtdummy" in the binding position.
   647 
   648 * Syntax: removed obsolete syntactic constant "_K" and its associated
   649 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   650 for example "A -> B" => "Pi A (%_. B)".
   651 
   652 * Pure: 'class_deps' command visualizes the subclass relation, using
   653 the graph browser tool.
   654 
   655 * Pure: 'print_theory' now suppresses certain internal declarations by
   656 default; use '!' option for full details.
   657 
   658 
   659 *** HOL ***
   660 
   661 * Method "metis" proves goals by applying the Metis general-purpose
   662 resolution prover (see also http://gilith.com/software/metis/).
   663 Examples are in the directory MetisExamples.  WARNING: the
   664 Isabelle/HOL-Metis integration does not yet work properly with
   665 multi-threading.
   666   
   667 * Command 'sledgehammer' invokes external automatic theorem provers as
   668 background processes.  It generates calls to the "metis" method if
   669 successful. These can be pasted into the proof.  Users do not have to
   670 wait for the automatic provers to return.  WARNING: does not really
   671 work with multi-threading.
   672 
   673 * New "auto_quickcheck" feature tests outermost goal statements for
   674 potential counter-examples.  Controlled by ML references
   675 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
   676 5000 milliseconds).  Fails silently if statements is outside of
   677 executable fragment, or any other codgenerator problem occurs.
   678 
   679 * New constant "undefined" with axiom "undefined x = undefined".
   680 
   681 * Added class "HOL.eq", allowing for code generation with polymorphic
   682 equality.
   683 
   684 * Some renaming of class constants due to canonical name prefixing in
   685 the new 'class' package:
   686 
   687     HOL.abs ~> HOL.abs_class.abs
   688     HOL.divide ~> HOL.divide_class.divide
   689     0 ~> HOL.zero_class.zero
   690     1 ~> HOL.one_class.one
   691     op + ~> HOL.plus_class.plus
   692     op - ~> HOL.minus_class.minus
   693     uminus ~> HOL.minus_class.uminus
   694     op * ~> HOL.times_class.times
   695     op < ~> HOL.ord_class.less
   696     op <= > HOL.ord_class.less_eq
   697     Nat.power ~> Power.power_class.power
   698     Nat.size ~> Nat.size_class.size
   699     Numeral.number_of ~> Numeral.number_class.number_of
   700     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
   701     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
   702     Orderings.min ~> Orderings.ord_class.min
   703     Orderings.max ~> Orderings.ord_class.max
   704     Divides.op div ~> Divides.div_class.div
   705     Divides.op mod ~> Divides.div_class.mod
   706     Divides.op dvd ~> Divides.div_class.dvd
   707 
   708 INCOMPATIBILITY.  Adaptions may be required in the following cases:
   709 
   710 a) User-defined constants using any of the names "plus", "minus",
   711 "times", "less" or "less_eq". The standard syntax translations for
   712 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
   713 names.
   714 
   715 b) Variables named "plus", "minus", "times", "less", "less_eq"
   716 INCOMPATIBILITY: use more specific names.
   717 
   718 c) Permutative equations (e.g. "a + b = b + a")
   719 Since the change of names also changes the order of terms, permutative
   720 rewrite rules may get applied in a different order. Experience shows
   721 that this is rarely the case (only two adaptions in the whole Isabelle
   722 distribution).  INCOMPATIBILITY: rewrite proofs
   723 
   724 d) ML code directly refering to constant names
   725 This in general only affects hand-written proof tactics, simprocs and
   726 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
   727 Consider using @{const_name} antiquotation.
   728 
   729 * New class "default" with associated constant "default".
   730 
   731 * Function "sgn" is now overloaded and available on int, real, complex
   732 (and other numeric types), using class "sgn".  Two possible defs of
   733 sgn are given as equational assumptions in the classes sgn_if and
   734 sgn_div_norm; ordered_idom now also inherits from sgn_if.
   735 INCOMPATIBILITY.
   736 
   737 * Locale "partial_order" now unified with class "order" (cf. theory
   738 Orderings), added parameter "less".  INCOMPATIBILITY.
   739 
   740 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
   741 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
   742 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
   743 
   744 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
   745 changed order of proof goals in instance proofs.
   746 
   747 * The transitivity reasoner for partial and linear orders is set up
   748 for classes "order" and "linorder".  Instances of the reasoner are available
   749 in all contexts importing or interpreting the corresponding locales.
   750 Method "order" invokes the reasoner separately; the reasoner
   751 is also integrated with the Simplifier as a solver.  Diagnostic
   752 command 'print_orders' shows the available instances of the reasoner
   753 in the current context.
   754 
   755 * Localized monotonicity predicate in theory "Orderings"; integrated
   756 lemmas max_of_mono and min_of_mono with this predicate.
   757 INCOMPATIBILITY.
   758 
   759 * Formulation of theorem "dense" changed slightly due to integration
   760 with new class dense_linear_order.
   761 
   762 * Uniform lattice theory development in HOL.
   763 
   764     constants "meet" and "join" now named "inf" and "sup"
   765     constant "Meet" now named "Inf"
   766 
   767     classes "meet_semilorder" and "join_semilorder" now named
   768       "lower_semilattice" and "upper_semilattice"
   769     class "lorder" now named "lattice"
   770     class "comp_lat" now named "complete_lattice"
   771 
   772     Instantiation of lattice classes allows explicit definitions
   773     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
   774 
   775   INCOMPATIBILITY.  Theorem renames:
   776 
   777     meet_left_le            ~> inf_le1
   778     meet_right_le           ~> inf_le2
   779     join_left_le            ~> sup_ge1
   780     join_right_le           ~> sup_ge2
   781     meet_join_le            ~> inf_sup_ord
   782     le_meetI                ~> le_infI
   783     join_leI                ~> le_supI
   784     le_meet                 ~> le_inf_iff
   785     le_join                 ~> ge_sup_conv
   786     meet_idempotent         ~> inf_idem
   787     join_idempotent         ~> sup_idem
   788     meet_comm               ~> inf_commute
   789     join_comm               ~> sup_commute
   790     meet_leI1               ~> le_infI1
   791     meet_leI2               ~> le_infI2
   792     le_joinI1               ~> le_supI1
   793     le_joinI2               ~> le_supI2
   794     meet_assoc              ~> inf_assoc
   795     join_assoc              ~> sup_assoc
   796     meet_left_comm          ~> inf_left_commute
   797     meet_left_idempotent    ~> inf_left_idem
   798     join_left_comm          ~> sup_left_commute
   799     join_left_idempotent    ~> sup_left_idem
   800     meet_aci                ~> inf_aci
   801     join_aci                ~> sup_aci
   802     le_def_meet             ~> le_iff_inf
   803     le_def_join             ~> le_iff_sup
   804     join_absorp2            ~> sup_absorb2
   805     join_absorp1            ~> sup_absorb1
   806     meet_absorp1            ~> inf_absorb1
   807     meet_absorp2            ~> inf_absorb2
   808     meet_join_absorp        ~> inf_sup_absorb
   809     join_meet_absorp        ~> sup_inf_absorb
   810     distrib_join_le         ~> distrib_sup_le
   811     distrib_meet_le         ~> distrib_inf_le
   812 
   813     add_meet_distrib_left   ~> add_inf_distrib_left
   814     add_join_distrib_left   ~> add_sup_distrib_left
   815     is_join_neg_meet        ~> is_join_neg_inf
   816     is_meet_neg_join        ~> is_meet_neg_sup
   817     add_meet_distrib_right  ~> add_inf_distrib_right
   818     add_join_distrib_right  ~> add_sup_distrib_right
   819     add_meet_join_distribs  ~> add_sup_inf_distribs
   820     join_eq_neg_meet        ~> sup_eq_neg_inf
   821     meet_eq_neg_join        ~> inf_eq_neg_sup
   822     add_eq_meet_join        ~> add_eq_inf_sup
   823     meet_0_imp_0            ~> inf_0_imp_0
   824     join_0_imp_0            ~> sup_0_imp_0
   825     meet_0_eq_0             ~> inf_0_eq_0
   826     join_0_eq_0             ~> sup_0_eq_0
   827     neg_meet_eq_join        ~> neg_inf_eq_sup
   828     neg_join_eq_meet        ~> neg_sup_eq_inf
   829     join_eq_if              ~> sup_eq_if
   830 
   831     mono_meet               ~> mono_inf
   832     mono_join               ~> mono_sup
   833     meet_bool_eq            ~> inf_bool_eq
   834     join_bool_eq            ~> sup_bool_eq
   835     meet_fun_eq             ~> inf_fun_eq
   836     join_fun_eq             ~> sup_fun_eq
   837     meet_set_eq             ~> inf_set_eq
   838     join_set_eq             ~> sup_set_eq
   839     meet1_iff               ~> inf1_iff
   840     meet2_iff               ~> inf2_iff
   841     meet1I                  ~> inf1I
   842     meet2I                  ~> inf2I
   843     meet1D1                 ~> inf1D1
   844     meet2D1                 ~> inf2D1
   845     meet1D2                 ~> inf1D2
   846     meet2D2                 ~> inf2D2
   847     meet1E                  ~> inf1E
   848     meet2E                  ~> inf2E
   849     join1_iff               ~> sup1_iff
   850     join2_iff               ~> sup2_iff
   851     join1I1                 ~> sup1I1
   852     join2I1                 ~> sup2I1
   853     join1I1                 ~> sup1I1
   854     join2I2                 ~> sup1I2
   855     join1CI                 ~> sup1CI
   856     join2CI                 ~> sup2CI
   857     join1E                  ~> sup1E
   858     join2E                  ~> sup2E
   859 
   860     is_meet_Meet            ~> is_meet_Inf
   861     Meet_bool_def           ~> Inf_bool_def
   862     Meet_fun_def            ~> Inf_fun_def
   863     Meet_greatest           ~> Inf_greatest
   864     Meet_lower              ~> Inf_lower
   865     Meet_set_def            ~> Inf_set_def
   866 
   867     Sup_def                 ~> Sup_Inf
   868     Sup_bool_eq             ~> Sup_bool_def
   869     Sup_fun_eq              ~> Sup_fun_def
   870     Sup_set_eq              ~> Sup_set_def
   871 
   872     listsp_meetI            ~> listsp_infI
   873     listsp_meet_eq          ~> listsp_inf_eq
   874 
   875     meet_min                ~> inf_min
   876     join_max                ~> sup_max
   877 
   878 * Added syntactic class "size"; overloaded constant "size" now has
   879 type "'a::size ==> bool"
   880 
   881 * Internal reorganisation of `size' of datatypes: size theorems
   882 "foo.size" are no longer subsumed by "foo.simps" (but are still
   883 simplification rules by default!); theorems "prod.size" now named
   884 "*.size".
   885 
   886 * Class "div" now inherits from class "times" rather than "type".
   887 INCOMPATIBILITY.
   888 
   889 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
   890 Linorder etc.  have disappeared; operations defined in terms of
   891 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
   892 
   893 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
   894 
   895 * HOL-Word: New extensive library and type for generic, fixed size
   896 machine words, with arithemtic, bit-wise, shifting and rotating
   897 operations, reflection into int, nat, and bool lists, automation for
   898 linear arithmetic (by automatic reflection into nat or int), including
   899 lemmas on overflow and monotonicity.  Instantiated to all appropriate
   900 arithmetic type classes, supporting automatic simplification of
   901 numerals on all operations.
   902 
   903 * Library/Boolean_Algebra: locales for abstract boolean algebras.
   904 
   905 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
   906 
   907 * Code generator library theories:
   908   - Code_Integer represents HOL integers by big integer literals in target
   909     languages.
   910   - Code_Char represents HOL characters by character literals in target
   911     languages.
   912   - Code_Char_chr like Code_Char, but also offers treatment of character
   913     codes; includes Code_Integer.
   914   - Executable_Set allows to generate code for finite sets using lists.
   915   - Executable_Rat implements rational numbers as triples (sign, enumerator,
   916     denominator).
   917   - Executable_Real implements a subset of real numbers, namly those
   918     representable by rational numbers.
   919   - Efficient_Nat implements natural numbers by integers, which in general will
   920     result in higher efficency; pattern matching with 0/Suc is eliminated;
   921     includes Code_Integer.
   922   - Code_Index provides an additional datatype index which is mapped to
   923     target-language built-in integers.
   924   - Code_Message provides an additional datatype message_string} which is isomorphic to
   925     strings; messages are mapped to target-language strings.
   926 
   927 * New package for inductive predicates
   928 
   929   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
   930 
   931     inductive
   932       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   933       for z_1 :: U_1 and ... and z_n :: U_m
   934     where
   935       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   936     | ...
   937 
   938   with full support for type-inference, rather than
   939 
   940     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   941 
   942     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   943     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   944 
   945     inductive "s z_1 ... z_m"
   946     intros
   947       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   948       ...
   949 
   950   For backward compatibility, there is a wrapper allowing inductive
   951   sets to be defined with the new package via
   952 
   953     inductive_set
   954       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   955       for z_1 :: U_1 and ... and z_n :: U_m
   956     where
   957       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
   958     | ...
   959 
   960   or
   961 
   962     inductive_set
   963       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
   964       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
   965       for z_1 :: U_1 and ... and z_n :: U_m
   966     where
   967       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
   968     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
   969     | ...
   970 
   971   if the additional syntax "p ..." is required.
   972 
   973   Numerous examples can be found in the subdirectories src/HOL/Auth,
   974   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
   975 
   976   INCOMPATIBILITIES:
   977 
   978   - Since declaration and definition of inductive sets or predicates
   979     is no longer separated, abbreviations involving the newly
   980     introduced sets or predicates must be specified together with the
   981     introduction rules after the 'where' keyword (see above), rather
   982     than before the actual inductive definition.
   983 
   984   - The variables in induction and elimination rules are now
   985     quantified in the order of their occurrence in the introduction
   986     rules, rather than in alphabetical order. Since this may break
   987     some proofs, these proofs either have to be repaired, e.g. by
   988     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
   989     statements of the form
   990 
   991       case (rule_i a_i_1 ... a_i_{k_i})
   992 
   993     or the old order of quantification has to be restored by explicitly adding
   994     meta-level quantifiers in the introduction rules, i.e.
   995 
   996       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
   997 
   998   - The format of the elimination rules is now
   999 
  1000       p z_1 ... z_m x_1 ... x_n ==>
  1001         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1002         ==> ... ==> P
  1003 
  1004     for predicates and
  1005 
  1006       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1007         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1008         ==> ... ==> P
  1009 
  1010     for sets rather than
  1011 
  1012       x : s z_1 ... z_m ==>
  1013         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1014         ==> ... ==> P
  1015 
  1016     This may require terms in goals to be expanded to n-tuples
  1017     (e.g. using case_tac or simplification with the split_paired_all
  1018     rule) before the above elimination rule is applicable.
  1019 
  1020   - The elimination or case analysis rules for (mutually) inductive
  1021     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1022     list of rules "p_1_..._p_k.elims" is no longer available.
  1023 
  1024 * New package "function"/"fun" for general recursive functions,
  1025 supporting mutual and nested recursion, definitions in local contexts,
  1026 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1027 for small examples, and the separate tutorial on the function
  1028 package. The old recdef "package" is still available as before, but
  1029 users are encouraged to use the new package.
  1030 
  1031 * Method "lexicographic_order" automatically synthesizes termination
  1032 relations as lexicographic combinations of size measures. 
  1033 
  1034 * Case-expressions allow arbitrary constructor-patterns (including
  1035 "_") and take their order into account, like in functional
  1036 programming.  Internally, this is translated into nested
  1037 case-expressions; missing cases are added and mapped to the predefined
  1038 constant "undefined". In complicated cases printing may no longer show
  1039 the original input but the internal form. Lambda-abstractions allow
  1040 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1041 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1042 variable.
  1043 
  1044 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1045 is an abbreviation for "of_nat :: nat => int". The simplification
  1046 rules for "of_nat" have been changed to work like "int" did
  1047 previously.  Potential INCOMPATIBILITY:
  1048   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1049   - of_nat_diff and of_nat_mult are no longer default simp rules
  1050 
  1051 * Method "algebra" solves polynomial equations over (semi)rings using
  1052 Groebner bases. The (semi)ring structure is defined by locales and the
  1053 tool setup depends on that generic context. Installing the method for
  1054 a specific type involves instantiating the locale and possibly adding
  1055 declarations for computation on the coefficients.  The method is
  1056 already instantiated for natural numbers and for the axiomatic class
  1057 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1058 CALCULEMUS 2007 for the general principles underlying this
  1059 architecture of context-aware proof-tools.
  1060 
  1061 * Method "ferrack" implements quantifier elimination over
  1062 special-purpose dense linear orders using locales (analogous to
  1063 "algebra"). The method is already installed for class
  1064 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1065 rat, etc.
  1066 
  1067 * Former constant "List.op @" now named "List.append".  Use ML
  1068 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1069 circumvent possible incompatibilities when working on ML level.
  1070 
  1071 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1072 
  1073 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1074 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1075 
  1076 * New syntax for Haskell-like list comprehension (input only), eg.
  1077 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1078 
  1079 * The special syntax for function "filter" has changed from [x :
  1080 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1081 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1082 
  1083 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1084 defined on nat only, as an abbreviation for [a..<Suc b]
  1085 INCOMPATIBILITY.
  1086 
  1087 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1088 
  1089 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1090 
  1091 * New lemma collection field_simps (an extension of ring_simps) for
  1092 manipulating (in)equations involving division. Multiplies with all
  1093 denominators that can be proved to be non-zero (in equations) or
  1094 positive/negative (in inequations).
  1095 
  1096 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1097 have been improved and renamed to ring_simps, group_simps and
  1098 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1099 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1100 
  1101 * Theory Library/Commutative_Ring: switched from recdef to function
  1102 package; constants add, mul, pow now curried.  Infix syntax for
  1103 algebraic operations.
  1104 
  1105 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1106 INCOMPATIBILITY.
  1107 
  1108 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1109 INCOMPATIBILITY.
  1110 
  1111 * HOL/records: generalised field-update to take a function on the
  1112 field rather than the new value: r(|A := x|) is translated to A_update
  1113 (K x) r The K-combinator that is internally used is called K_record.
  1114 INCOMPATIBILITY: Usage of the plain update functions has to be
  1115 adapted.
  1116  
  1117 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1118 * x = 0, which are required for a semiring.  Richer structures do not
  1119 inherit from semiring_0 anymore, because this property is a theorem
  1120 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1121 there is more to prove, but this is mostly trivial.
  1122 
  1123 * Class "recpower" is generalized to arbitrary monoids, not just
  1124 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1125 commutativity or semiring properties additionally.
  1126 
  1127 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1128 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1129 better use 'abbreviation'.
  1130 
  1131 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1132 
  1133 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1134 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1135 significant changes for setting up numeral syntax for types:
  1136   - New constants Numeral.pred and Numeral.succ instead
  1137       of former Numeral.bin_pred and Numeral.bin_succ.
  1138   - Use integer operations instead of bin_add, bin_mult and so on.
  1139   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1140   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1141 
  1142 See src/HOL/Integ/IntArith.thy for an example setup.
  1143 
  1144 * Command 'normal_form' computes the normal form of a term that may
  1145 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1146 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1147 heavy-duty computations because the functions are compiled to ML
  1148 first.  Correspondingly, a method "normalization" is provided.  See
  1149 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1150 
  1151 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1152 25 like -->); output depends on the "iff" print_mode, the default is
  1153 "A = B" (with priority 50).
  1154 
  1155 * Relations less (<) and less_eq (<=) are also available on type bool.
  1156 Modified syntax to disallow nesting without explicit parentheses,
  1157 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1158 INCOMPATIBILITY.
  1159 
  1160 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1161 
  1162 * Relation composition operator "op O" now has precedence 75 and binds
  1163 stronger than union and intersection. INCOMPATIBILITY.
  1164 
  1165 * The old set interval syntax "{m..n(}" (and relatives) has been
  1166 removed.  Use "{m..<n}" (and relatives) instead.
  1167 
  1168 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1169 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1170 ``declare [[simproc del: neq]]''.
  1171 
  1172 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1173 True/False.
  1174 
  1175 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1176 
  1177 * Theorem setsum_mult renamed to setsum_right_distrib.
  1178 
  1179 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1180 ``rule'' method.
  1181 
  1182 * Reimplemented methods "sat" and "satx", with several improvements:
  1183 goals no longer need to be stated as "<prems> ==> False", equivalences
  1184 (i.e. "=" on type bool) are handled, variable names of the form
  1185 "lit_<n>" are no longer reserved, significant speedup.
  1186 
  1187 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1188 zChaff is still supported as well.
  1189 
  1190 * 'inductive' and 'datatype': provide projections of mutual rules,
  1191 bundled as foo_bar.inducts;
  1192 
  1193 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1194 Library.
  1195 
  1196 * Library: moved theory Accessible_Part to main HOL.
  1197 
  1198 * Library: added theory Coinductive_List of potentially infinite lists
  1199 as greatest fixed-point.
  1200 
  1201 * Library: added theory AssocList which implements (finite) maps as
  1202 association lists.
  1203 
  1204 * Method "evaluation" solves goals (i.e. a boolean expression)
  1205 efficiently by compiling it to ML.  The goal is "proved" (via an
  1206 oracle) if it evaluates to True.
  1207 
  1208 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1209 also when invoked by the simplifier.  This results in the Simplifier
  1210 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1211 Configuration option fast_arith_split_limit=0 recovers the old
  1212 behavior.
  1213 
  1214 * Support for hex (0x20) and binary (0b1001) numerals.
  1215 
  1216 * New method: reify eqs (t), where eqs are equations for an
  1217 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1218 parameter, computes a term s::'b and a list xs::'a list and proves the
  1219 theorem I xs s = t. This is also known as reification or quoting. The
  1220 resulting theorem is applied to the subgoal to substitute t with I xs
  1221 s.  If t is omitted, the subgoal itself is reified.
  1222 
  1223 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1224 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1225 where f is supposed to be a computable function (in the sense of code
  1226 generattion). The method uses reify to compute s and xs as above then
  1227 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1228 r and finally gets the theorem t = r, which is again applied to the
  1229 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1230 
  1231 * Reflection: Automatic reification now handels binding, an example is
  1232 available in src/HOL/ex/ReflectionEx.thy
  1233 
  1234 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1235 command 'statespace' that is similar to 'record', but introduces an
  1236 abstract specification based on the locale infrastructure instead of
  1237 HOL types.  This leads to extra flexibility in composing state spaces,
  1238 in particular multiple inheritance and renaming of components.
  1239 
  1240 
  1241 *** HOL-Complex ***
  1242 
  1243 * Hyperreal: Functions root and sqrt are now defined on negative real
  1244 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1245 Nonnegativity side conditions have been removed from many lemmas, so
  1246 that more subgoals may now be solved by simplification; potential
  1247 INCOMPATIBILITY.
  1248 
  1249 * Real: new type classes formalize real normed vector spaces and
  1250 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1251 and norm :: 'a => real.
  1252 
  1253 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1254 reals into other types. The overloaded constant Reals :: 'a set is now
  1255 defined as range of_real; potential INCOMPATIBILITY.
  1256 
  1257 * Real: proper support for ML code generation, including 'quickcheck'.
  1258 Reals are implemented as arbitrary precision rationals.
  1259 
  1260 * Hyperreal: Several constants that previously worked only for the
  1261 reals have been generalized, so they now work over arbitrary vector
  1262 spaces. Type annotations may need to be added in some cases; potential
  1263 INCOMPATIBILITY.
  1264 
  1265   Infinitesimal  :: ('a::real_normed_vector) star set
  1266   HFinite        :: ('a::real_normed_vector) star set
  1267   HInfinite      :: ('a::real_normed_vector) star set
  1268   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1269   monad          :: ('a::real_normed_vector) star => 'a star set
  1270   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1271   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1272   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1273   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1274   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1275   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1276   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1277   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1278   sgn            :: 'a::real_normed_vector => 'a
  1279   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1280 
  1281 * Complex: Some complex-specific constants are now abbreviations for
  1282 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1283 hnorm.  Other constants have been entirely removed in favor of the
  1284 polymorphic versions (INCOMPATIBILITY):
  1285 
  1286   approx        <-- capprox
  1287   HFinite       <-- CFinite
  1288   HInfinite     <-- CInfinite
  1289   Infinitesimal <-- CInfinitesimal
  1290   monad         <-- cmonad
  1291   galaxy        <-- cgalaxy
  1292   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1293   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1294   (ns)deriv     <-- (ns)cderiv
  1295 
  1296 
  1297 *** HOL-Algebra ***
  1298 
  1299 * Formalisation of ideals and the quotient construction over rings.
  1300 
  1301 * Order and lattice theory no longer based on records.
  1302 INCOMPATIBILITY.
  1303 
  1304 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1305 greatest_closed.  INCOMPATIBILITY.
  1306 
  1307 * Method algebra is now set up via an attribute.  For examples see
  1308 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1309 of algebraic structures.
  1310 
  1311 * Renamed theory CRing to Ring.
  1312 
  1313 
  1314 *** HOL-Nominal ***
  1315 
  1316 * Substantial, yet incomplete support for nominal datatypes (binding
  1317 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1318 src/HOL/Nominal/Examples.  Prospective users should consult
  1319 http://isabelle.in.tum.de/nominal/
  1320 
  1321 
  1322 *** ML ***
  1323 
  1324 * ML basics: just one true type int, which coincides with IntInf.int
  1325 (even on SML/NJ).
  1326 
  1327 * ML within Isar: antiquotations allow to embed statically-checked
  1328 formal entities in the source, referring to the context available at
  1329 compile-time.  For example:
  1330 
  1331 ML {* @{sort "{zero,one}"} *}
  1332 ML {* @{typ "'a => 'b"} *}
  1333 ML {* @{term "%x. x"} *}
  1334 ML {* @{prop "x == y"} *}
  1335 ML {* @{ctyp "'a => 'b"} *}
  1336 ML {* @{cterm "%x. x"} *}
  1337 ML {* @{cprop "x == y"} *}
  1338 ML {* @{thm asm_rl} *}
  1339 ML {* @{thms asm_rl} *}
  1340 ML {* @{type_name c} *}
  1341 ML {* @{type_syntax c} *}
  1342 ML {* @{const_name c} *}
  1343 ML {* @{const_syntax c} *}
  1344 ML {* @{context} *}
  1345 ML {* @{theory} *}
  1346 ML {* @{theory Pure} *}
  1347 ML {* @{theory_ref} *}
  1348 ML {* @{theory_ref Pure} *}
  1349 ML {* @{simpset} *}
  1350 ML {* @{claset} *}
  1351 ML {* @{clasimpset} *}
  1352 
  1353 The same works for sources being ``used'' within an Isar context.
  1354 
  1355 * ML in Isar: improved error reporting; extra verbosity with
  1356 ML_Context.trace enabled.
  1357 
  1358 * Pure/General/table.ML: the join operations now works via exceptions
  1359 DUP/SAME instead of type option. This is simpler in simple cases, and
  1360 admits slightly more efficient complex applications.
  1361 
  1362 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1363 use Context.generic instead of just theory.
  1364 
  1365 * Pure: datatype Context.generic joins theory/Proof.context and
  1366 provides some facilities for code that works in either kind of
  1367 context, notably GenericDataFun for uniform theory and proof data.
  1368 
  1369 * Pure: simplified internal attribute type, which is now always
  1370 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1371 local (Proof.context) attributes have been discontinued, while
  1372 minimizing code duplication. Thm.rule_attribute and
  1373 Thm.declaration_attribute build canonical attributes; see also structure
  1374 Context for further operations on Context.generic, notably
  1375 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1376 declarations and definitions.
  1377 
  1378 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1379 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1380 init only required for impure data. INCOMPATIBILITY: empty really need
  1381 to be empty (no dependencies on theory content!)
  1382 
  1383 * Pure/kernel: consts certification ignores sort constraints given in
  1384 signature declarations. (This information is not relevant to the
  1385 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1386 potential INCOMPATIBILITY.
  1387 
  1388 * Pure: axiomatic type classes are now purely definitional, with
  1389 explicit proofs of class axioms and super class relations performed
  1390 internally. See Pure/axclass.ML for the main internal interfaces --
  1391 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1392 AxClass.axiomatize_class/classrel/arity supersede
  1393 Sign.add_classes/classrel/arities.
  1394 
  1395 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1396 global/local versions on theory vs. Proof.context have been
  1397 discontinued; Attrib.syntax and Method.syntax have been adapted
  1398 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1399 attributes, methods, etc.
  1400 
  1401 * Pure: several functions of signature "... -> theory -> theory * ..."
  1402 have been reoriented to "... -> theory -> ... * theory" in order to
  1403 allow natural usage in combination with the ||>, ||>>, |-> and
  1404 fold_map combinators.
  1405 
  1406 * Pure: official theorem names (closed derivations) and additional
  1407 comments (tags) are now strictly separate.  Name hints -- which are
  1408 maintained as tags -- may be attached any time without affecting the
  1409 derivation.
  1410 
  1411 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1412 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1413 achieve the old behaviour.
  1414 
  1415 * Pure: the "Goal" constant is now called "prop", supporting a
  1416 slightly more general idea of ``protecting'' meta-level rule
  1417 statements.
  1418 
  1419 * Pure: Logic.(un)varify only works in a global context, which is now
  1420 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1421 Logic.legacy_(un)varify as temporary workaround.
  1422 
  1423 * Pure: structure Name provides scalable operations for generating
  1424 internal variable names, notably Name.variants etc.  This replaces
  1425 some popular functions from term.ML:
  1426 
  1427   Term.variant		->  Name.variant
  1428   Term.variantlist	->  Name.variant_list
  1429   Term.invent_names	->  Name.invent_list
  1430 
  1431 Note that low-level renaming rarely occurs in new code -- operations
  1432 from structure Variable are used instead (see below).
  1433 
  1434 * Pure: structure Variable provides fundamental operations for proper
  1435 treatment of fixed/schematic variables in a context.  For example,
  1436 Variable.import introduces fixes for schematics of given facts and
  1437 Variable.export reverses the effect (up to renaming) -- this replaces
  1438 various freeze_thaw operations.
  1439 
  1440 * Pure: structure Goal provides simple interfaces for
  1441 init/conclude/finish and tactical prove operations (replacing former
  1442 Tactic.prove).  Goal.prove is the canonical way to prove results
  1443 within a given context; Goal.prove_global is a degraded version for
  1444 theory level goals, including a global Drule.standard.  Note that
  1445 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  1446 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  1447 in a locale context).
  1448 
  1449 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  1450 and type checking (Syntax.check_term etc.), with common combinations
  1451 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  1452 which are considered legacy and await removal.
  1453 
  1454 * Pure/Syntax: generic interfaces for type unchecking
  1455 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  1456 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  1457 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  1458 available for convenience, but refer to the very same operations using
  1459 a mere theory instead of a full context.
  1460 
  1461 * Isar: simplified treatment of user-level errors, using exception
  1462 ERROR of string uniformly.  Function error now merely raises ERROR,
  1463 without any side effect on output channels.  The Isar toplevel takes
  1464 care of proper display of ERROR exceptions.  ML code may use plain
  1465 handle/can/try; cat_error may be used to concatenate errors like this:
  1466 
  1467   ... handle ERROR msg => cat_error msg "..."
  1468 
  1469 Toplevel ML code (run directly or through the Isar toplevel) may be
  1470 embedded into the Isar toplevel with exception display/debug like
  1471 this:
  1472 
  1473   Isar.toplevel (fn () => ...)
  1474 
  1475 INCOMPATIBILITY, removed special transform_error facilities, removed
  1476 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  1477 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  1478 -- use plain ERROR instead.
  1479 
  1480 * Isar: theory setup now has type (theory -> theory), instead of a
  1481 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  1482 
  1483 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  1484 ProofContext.debug/verbose flags.
  1485 
  1486 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  1487 theory before entering a proof state.  Transactions now always see a
  1488 quasi-functional intermediate checkpoint, both in interactive and
  1489 batch mode.
  1490 
  1491 * Isar: simplified interfaces for outer syntax.  Renamed
  1492 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  1493 OuterSyntax.add_parsers -- this functionality is now included in
  1494 OuterSyntax.command etc.  INCOMPATIBILITY.
  1495 
  1496 * Simplifier: the simpset of a running simplification process now
  1497 contains a proof context (cf. Simplifier.the_context), which is the
  1498 very context that the initial simpset has been retrieved from (by
  1499 simpset_of/local_simpset_of).  Consequently, all plug-in components
  1500 (solver, looper etc.) may depend on arbitrary proof data.
  1501 
  1502 * Simplifier.inherit_context inherits the proof context (plus the
  1503 local bounds) of the current simplification process; any simproc
  1504 etc. that calls the Simplifier recursively should do this!  Removed
  1505 former Simplifier.inherit_bounds, which is already included here --
  1506 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  1507 specify an explicit context using Simplifier.context/theory_context.
  1508 
  1509 * Simplifier/Classical Reasoner: more abstract interfaces
  1510 change_simpset/claset for modifying the simpset/claset reference of a
  1511 theory; raw versions simpset/claset_ref etc. have been discontinued --
  1512 INCOMPATIBILITY.
  1513 
  1514 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  1515 "Trueprop" etc.
  1516 
  1517 
  1518 *** System ***
  1519 
  1520 * settings: the default heap location within ISABELLE_HOME_USER now
  1521 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  1522 Isabelle installations.
  1523 
  1524 * isabelle-process: option -S (secure mode) disables some critical
  1525 operations, notably runtime compilation and evaluation of ML source
  1526 code.
  1527 
  1528 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  1529 
  1530 * Support for parallel execution, using native multicore support of
  1531 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  1532 independent theories, according to the given theory header
  1533 specifications. The maximum number of worker threads is specified via
  1534 usedir option -M or the "max-threads" setting in Proof General. A
  1535 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  1536 to 6 on a 8-core machine.  User-code needs to observe certain
  1537 guidelines for thread-safe programming, see appendix A in the Isar
  1538 Implementation manual.
  1539 
  1540 
  1541 
  1542 New in Isabelle2005 (October 2005)
  1543 ----------------------------------
  1544 
  1545 *** General ***
  1546 
  1547 * Theory headers: the new header syntax for Isar theories is
  1548 
  1549   theory <name>
  1550   imports <theory1> ... <theoryN>
  1551   uses <file1> ... <fileM>
  1552   begin
  1553 
  1554 where the 'uses' part is optional.  The previous syntax
  1555 
  1556   theory <name> = <theory1> + ... + <theoryN>:
  1557 
  1558 will disappear in the next release.  Use isatool fixheaders to convert
  1559 existing theory files.  Note that there is no change in ancient
  1560 non-Isar theories now, but these will disappear soon.
  1561 
  1562 * Theory loader: parent theories can now also be referred to via
  1563 relative and absolute paths.
  1564 
  1565 * Command 'find_theorems' searches for a list of criteria instead of a
  1566 list of constants. Known criteria are: intro, elim, dest, name:string,
  1567 simp:term, and any term. Criteria can be preceded by '-' to select
  1568 theorems that do not match. Intro, elim, dest select theorems that
  1569 match the current goal, name:s selects theorems whose fully qualified
  1570 name contain s, and simp:term selects all simplification rules whose
  1571 lhs match term.  Any other term is interpreted as pattern and selects
  1572 all theorems matching the pattern. Available in ProofGeneral under
  1573 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  1574 
  1575   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  1576 
  1577 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  1578 matching the current goal as introduction rule and not having "HOL."
  1579 in their name (i.e. not being defined in theory HOL).
  1580 
  1581 * Command 'thms_containing' has been discontinued in favour of
  1582 'find_theorems'; INCOMPATIBILITY.
  1583 
  1584 * Communication with Proof General is now 8bit clean, which means that
  1585 Unicode text in UTF-8 encoding may be used within theory texts (both
  1586 formal and informal parts).  Cf. option -U of the Isabelle Proof
  1587 General interface.  Here are some simple examples (cf. src/HOL/ex):
  1588 
  1589   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  1590   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  1591 
  1592 * Improved efficiency of the Simplifier and, to a lesser degree, the
  1593 Classical Reasoner.  Typical big applications run around 2 times
  1594 faster.
  1595 
  1596 
  1597 *** Document preparation ***
  1598 
  1599 * Commands 'display_drafts' and 'print_drafts' perform simple output
  1600 of raw sources.  Only those symbols that do not require additional
  1601 LaTeX packages (depending on comments in isabellesym.sty) are
  1602 displayed properly, everything else is left verbatim.  isatool display
  1603 and isatool print are used as front ends (these are subject to the
  1604 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  1605 
  1606 * Command tags control specific markup of certain regions of text,
  1607 notably folding and hiding.  Predefined tags include "theory" (for
  1608 theory begin and end), "proof" for proof commands, and "ML" for
  1609 commands involving ML code; the additional tags "visible" and
  1610 "invisible" are unused by default.  Users may give explicit tag
  1611 specifications in the text, e.g. ''by %invisible (auto)''.  The
  1612 interpretation of tags is determined by the LaTeX job during document
  1613 preparation: see option -V of isatool usedir, or options -n and -t of
  1614 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  1615 \isadroptag.
  1616 
  1617 Several document versions may be produced at the same time via isatool
  1618 usedir (the generated index.html will link all of them).  Typical
  1619 specifications include ''-V document=theory,proof,ML'' to present
  1620 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  1621 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  1622 these parts without any formal replacement text.  The Isabelle site
  1623 default settings produce ''document'' and ''outline'' versions as
  1624 specified above.
  1625 
  1626 * Several new antiquotations:
  1627 
  1628   @{term_type term} prints a term with its type annotated;
  1629 
  1630   @{typeof term} prints the type of a term;
  1631 
  1632   @{const const} is the same as @{term const}, but checks that the
  1633   argument is a known logical constant;
  1634 
  1635   @{term_style style term} and @{thm_style style thm} print a term or
  1636   theorem applying a "style" to it
  1637 
  1638   @{ML text}
  1639 
  1640 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  1641 definitions, equations, inequations etc., 'concl' printing only the
  1642 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  1643 to print the specified premise.  TermStyle.add_style provides an ML
  1644 interface for introducing further styles.  See also the "LaTeX Sugar"
  1645 document practical applications.  The ML antiquotation prints
  1646 type-checked ML expressions verbatim.
  1647 
  1648 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  1649 and 'text' support optional locale specification '(in loc)', which
  1650 specifies the default context for interpreting antiquotations.  For
  1651 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  1652 
  1653 * Option 'locale=NAME' of antiquotations specifies an alternative
  1654 context interpreting the subsequent argument.  For example: @{thm
  1655 [locale=lattice] inf_assoc}.
  1656 
  1657 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  1658 a proof context.
  1659 
  1660 * Proper output of antiquotations for theory commands involving a
  1661 proof context (such as 'locale' or 'theorem (in loc) ...').
  1662 
  1663 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  1664 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  1665 
  1666 * isatool usedir: new option -C (default true) controls whether option
  1667 -D should include a copy of the original document directory; -C false
  1668 prevents unwanted effects such as copying of administrative CVS data.
  1669 
  1670 
  1671 *** Pure ***
  1672 
  1673 * Considerably improved version of 'constdefs' command.  Now performs
  1674 automatic type-inference of declared constants; additional support for
  1675 local structure declarations (cf. locales and HOL records), see also
  1676 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  1677 sequential dependencies of definitions within a single 'constdefs'
  1678 section; moreover, the declared name needs to be an identifier.  If
  1679 all fails, consider to fall back on 'consts' and 'defs' separately.
  1680 
  1681 * Improved indexed syntax and implicit structures.  First of all,
  1682 indexed syntax provides a notational device for subscripted
  1683 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  1684 expressions.  Secondly, in a local context with structure
  1685 declarations, number indexes \<^sub>n or the empty index (default
  1686 number 1) refer to a certain fixed variable implicitly; option
  1687 show_structs controls printing of implicit structures.  Typical
  1688 applications of these concepts involve record types and locales.
  1689 
  1690 * New command 'no_syntax' removes grammar declarations (and
  1691 translations) resulting from the given syntax specification, which is
  1692 interpreted in the same manner as for the 'syntax' command.
  1693 
  1694 * 'Advanced' translation functions (parse_translation etc.) may depend
  1695 on the signature of the theory context being presently used for
  1696 parsing/printing, see also isar-ref manual.
  1697 
  1698 * Improved 'oracle' command provides a type-safe interface to turn an
  1699 ML expression of type theory -> T -> term into a primitive rule of
  1700 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  1701 is already included here); see also FOL/ex/IffExample.thy;
  1702 INCOMPATIBILITY.
  1703 
  1704 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  1705 before); "cI" is no longer bound, use "c.intro" instead.
  1706 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  1707 axclasses vs. locales.
  1708 
  1709 * Improved internal renaming of symbolic identifiers -- attach primes
  1710 instead of base 26 numbers.
  1711 
  1712 * New flag show_question_marks controls printing of leading question
  1713 marks in schematic variable names.
  1714 
  1715 * In schematic variable names, *any* symbol following \<^isub> or
  1716 \<^isup> is now treated as part of the base name.  For example, the
  1717 following works without printing of awkward ".0" indexes:
  1718 
  1719   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  1720     by simp
  1721 
  1722 * Inner syntax includes (*(*nested*) comments*).
  1723 
  1724 * Pretty printer now supports unbreakable blocks, specified in mixfix
  1725 annotations as "(00...)".
  1726 
  1727 * Clear separation of logical types and nonterminals, where the latter
  1728 may only occur in 'syntax' specifications or type abbreviations.
  1729 Before that distinction was only partially implemented via type class
  1730 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  1731 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  1732 exotic syntax specifications may require further adaption
  1733 (e.g. Cube/Cube.thy).
  1734 
  1735 * Removed obsolete type class "logic", use the top sort {} instead.
  1736 Note that non-logical types should be declared as 'nonterminals'
  1737 rather than 'types'.  INCOMPATIBILITY for new object-logic
  1738 specifications.
  1739 
  1740 * Attributes 'induct' and 'cases': type or set names may now be
  1741 locally fixed variables as well.
  1742 
  1743 * Simplifier: can now control the depth to which conditional rewriting
  1744 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  1745 Limit.
  1746 
  1747 * Simplifier: simplification procedures may now take the current
  1748 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  1749 interface), which is very useful for calling the Simplifier
  1750 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  1751 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  1752 low-level mk_simproc no longer applies Logic.varify internally, to
  1753 allow for use in a context of fixed variables.
  1754 
  1755 * thin_tac now works even if the assumption being deleted contains !!
  1756 or ==>.  More generally, erule now works even if the major premise of
  1757 the elimination rule contains !! or ==>.
  1758 
  1759 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  1760 
  1761 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  1762 from Pure, which contains all common declarations already.  Both
  1763 theories are defined via plain Isabelle/Isar .thy files.
  1764 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  1765 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  1766 use isatool fixcpure to adapt your theory and ML sources.
  1767 
  1768 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  1769 selections of theorems in named facts via index ranges.
  1770 
  1771 * 'print_theorems': in theory mode, really print the difference
  1772 wrt. the last state (works for interactive theory development only),
  1773 in proof mode print all local facts (cf. 'print_facts');
  1774 
  1775 * 'hide': option '(open)' hides only base names.
  1776 
  1777 * More efficient treatment of intermediate checkpoints in interactive
  1778 theory development.
  1779 
  1780 * Code generator is now invoked via code_module (incremental code
  1781 generation) and code_library (modular code generation, ML structures
  1782 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  1783 must be quoted when used as identifiers.
  1784 
  1785 * New 'value' command for reading, evaluating and printing terms using
  1786 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  1787 quoted when used as identifier.
  1788 
  1789 
  1790 *** Locales ***
  1791 
  1792 * New commands for the interpretation of locale expressions in
  1793 theories (1), locales (2) and proof contexts (3).  These generate
  1794 proof obligations from the expression specification.  After the
  1795 obligations have been discharged, theorems of the expression are added
  1796 to the theory, target locale or proof context.  The synopsis of the
  1797 commands is a follows:
  1798 
  1799   (1) interpretation expr inst
  1800   (2) interpretation target < expr
  1801   (3) interpret expr inst
  1802 
  1803 Interpretation in theories and proof contexts require a parameter
  1804 instantiation of terms from the current context.  This is applied to
  1805 specifications and theorems of the interpreted expression.
  1806 Interpretation in locales only permits parameter renaming through the
  1807 locale expression.  Interpretation is smart in that interpretations
  1808 that are active already do not occur in proof obligations, neither are
  1809 instantiated theorems stored in duplicate.  Use 'print_interps' to
  1810 inspect active interpretations of a particular locale.  For details,
  1811 see the Isar Reference manual.  Examples can be found in
  1812 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  1813 
  1814 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  1815 'interpret' instead.
  1816 
  1817 * New context element 'constrains' for adding type constraints to
  1818 parameters.
  1819 
  1820 * Context expressions: renaming of parameters with syntax
  1821 redeclaration.
  1822 
  1823 * Locale declaration: 'includes' disallowed.
  1824 
  1825 * Proper static binding of attribute syntax -- i.e. types / terms /
  1826 facts mentioned as arguments are always those of the locale definition
  1827 context, independently of the context of later invocations.  Moreover,
  1828 locale operations (renaming and type / term instantiation) are applied
  1829 to attribute arguments as expected.
  1830 
  1831 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  1832 actual attributes; rare situations may require Attrib.attribute to
  1833 embed those attributes into Attrib.src that lack concrete syntax.
  1834 Attribute implementations need to cooperate properly with the static
  1835 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  1836 Attrib.XXX_thm etc. already do the right thing without further
  1837 intervention.  Only unusual applications -- such as "where" or "of"
  1838 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  1839 on the context and the facts involved -- may have to assign parsed
  1840 values to argument tokens explicitly.
  1841 
  1842 * Changed parameter management in theorem generation for long goal
  1843 statements with 'includes'.  INCOMPATIBILITY: produces a different
  1844 theorem statement in rare situations.
  1845 
  1846 * Locale inspection command 'print_locale' omits notes elements.  Use
  1847 'print_locale!' to have them included in the output.
  1848 
  1849 
  1850 *** Provers ***
  1851 
  1852 * Provers/hypsubst.ML: improved version of the subst method, for
  1853 single-step rewriting: it now works in bound variable contexts. New is
  1854 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  1855 rewrite a different subterm than the original subst method, which is
  1856 still available as 'simplesubst'.
  1857 
  1858 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  1859 and quasi orders.
  1860 
  1861 * Provers/trancl.ML: new transitivity reasoner for transitive and
  1862 reflexive-transitive closure of relations.
  1863 
  1864 * Provers/blast.ML: new reference depth_limit to make blast's depth
  1865 limit (previously hard-coded with a value of 20) user-definable.
  1866 
  1867 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  1868 is peformed already.  Object-logics merely need to finish their
  1869 initial simpset configuration as before.  INCOMPATIBILITY.
  1870 
  1871 
  1872 *** HOL ***
  1873 
  1874 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  1875 
  1876   syntax (epsilon)
  1877     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  1878 
  1879 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  1880 and x-symbol; use option '-m epsilon' to get it actually printed.
  1881 Moreover, the mathematically important symbolic identifier \<epsilon>
  1882 becomes available as variable, constant etc.  INCOMPATIBILITY,
  1883 
  1884 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  1885 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  1886 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  1887 support corresponding Isar calculations.
  1888 
  1889 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  1890 instead of ":".
  1891 
  1892 * theory SetInterval: changed the syntax for open intervals:
  1893 
  1894   Old       New
  1895   {..n(}    {..<n}
  1896   {)n..}    {n<..}
  1897   {m..n(}   {m..<n}
  1898   {)m..n}   {m<..n}
  1899   {)m..n(}  {m<..<n}
  1900 
  1901 The old syntax is still supported but will disappear in the next
  1902 release.  For conversion use the following Emacs search and replace
  1903 patterns (these are not perfect but work quite well):
  1904 
  1905   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  1906   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  1907 
  1908 * Theory Commutative_Ring (in Library): method comm_ring for proving
  1909 equalities in commutative rings; method 'algebra' provides a generic
  1910 interface.
  1911 
  1912 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  1913 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  1914 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  1915 be a tuple pattern.
  1916 
  1917 Some new syntax forms are available:
  1918 
  1919   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  1920   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  1921   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  1922   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  1923 
  1924 The latter form "\<Sum>x < k. e" used to be based on a separate
  1925 function "Summation", which has been discontinued.
  1926 
  1927 * theory Finite_Set: in structured induction proofs, the insert case
  1928 is now 'case (insert x F)' instead of the old counterintuitive 'case
  1929 (insert F x)'.
  1930 
  1931 * The 'refute' command has been extended to support a much larger
  1932 fragment of HOL, including axiomatic type classes, constdefs and
  1933 typedefs, inductive datatypes and recursion.
  1934 
  1935 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  1936 Requires zChaff with proof generation to be installed.  See
  1937 HOL/ex/SAT_Examples.thy for examples.
  1938 
  1939 * Datatype induction via method 'induct' now preserves the name of the
  1940 induction variable. For example, when proving P(xs::'a list) by
  1941 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  1942 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  1943 in unstructured proof scripts.
  1944 
  1945 * Reworked implementation of records.  Improved scalability for
  1946 records with many fields, avoiding performance problems for type
  1947 inference. Records are no longer composed of nested field types, but
  1948 of nested extension types. Therefore the record type only grows linear
  1949 in the number of extensions and not in the number of fields.  The
  1950 top-level (users) view on records is preserved.  Potential
  1951 INCOMPATIBILITY only in strange cases, where the theory depends on the
  1952 old record representation. The type generated for a record is called
  1953 <record_name>_ext_type.
  1954 
  1955 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  1956 proofs triggered by a record definition or a simproc (if
  1957 quick_and_dirty is enabled).  Definitions of large records can take
  1958 quite long.
  1959 
  1960 New simproc record_upd_simproc for simplification of multiple record
  1961 updates enabled by default.  Moreover, trivial updates are also
  1962 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  1963 occasionally, since simplification is more powerful by default.
  1964 
  1965 * typedef: proper support for polymorphic sets, which contain extra
  1966 type-variables in the term.
  1967 
  1968 * Simplifier: automatically reasons about transitivity chains
  1969 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  1970 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  1971 old proofs break occasionally as simplification may now solve more
  1972 goals than previously.
  1973 
  1974 * Simplifier: converts x <= y into x = y if assumption y <= x is
  1975 present.  Works for all partial orders (class "order"), in particular
  1976 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  1977 just like y <= x.
  1978 
  1979 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  1980 bound variable or a constant then the let is unfolded.  Otherwise
  1981 first a is simplified to b, and then f b is simplified to g. If
  1982 possible we abstract b from g arriving at "let x = b in h x",
  1983 otherwise we unfold the let and arrive at g.  The simproc can be
  1984 enabled/disabled by the reference use_let_simproc.  Potential
  1985 INCOMPATIBILITY since simplification is more powerful by default.
  1986 
  1987 * Classical reasoning: the meson method now accepts theorems as arguments.
  1988 
  1989 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  1990 jobs to provide advice on the provability of subgoals.
  1991 
  1992 * Theory OrderedGroup and Ring_and_Field: various additions and
  1993 improvements to faciliate calculations involving equalities and
  1994 inequalities.
  1995 
  1996 The following theorems have been eliminated or modified
  1997 (INCOMPATIBILITY):
  1998 
  1999   abs_eq             now named abs_of_nonneg
  2000   abs_of_ge_0        now named abs_of_nonneg
  2001   abs_minus_eq       now named abs_of_nonpos
  2002   imp_abs_id         now named abs_of_nonneg
  2003   imp_abs_neg_id     now named abs_of_nonpos
  2004   mult_pos           now named mult_pos_pos
  2005   mult_pos_le        now named mult_nonneg_nonneg
  2006   mult_pos_neg_le    now named mult_nonneg_nonpos
  2007   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2008   mult_neg           now named mult_neg_neg
  2009   mult_neg_le        now named mult_nonpos_nonpos
  2010 
  2011 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2012      
  2013      zero_le_square
  2014      not_square_less_zero 
  2015 
  2016   The following lemmas have been deleted from Real/RealPow:
  2017   
  2018      realpow_zero_zero
  2019      realpow_two
  2020      realpow_less
  2021      zero_le_power
  2022      realpow_two_le
  2023      abs_realpow_two
  2024      realpow_two_abs     
  2025 
  2026 * Theory Parity: added rules for simplifying exponents.
  2027 
  2028 * Theory List:
  2029 
  2030 The following theorems have been eliminated or modified
  2031 (INCOMPATIBILITY):
  2032 
  2033   list_all_Nil       now named list_all.simps(1)
  2034   list_all_Cons      now named list_all.simps(2)
  2035   list_all_conv      now named list_all_iff
  2036   set_mem_eq         now named mem_iff
  2037 
  2038 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2039 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2040 
  2041 
  2042 *** HOL-Complex ***
  2043 
  2044 * Theory RealDef: better support for embedding natural numbers and
  2045 integers in the reals.
  2046 
  2047 The following theorems have been eliminated or modified
  2048 (INCOMPATIBILITY):
  2049 
  2050   exp_ge_add_one_self  now requires no hypotheses
  2051   real_of_int_add      reversed direction of equality (use [symmetric])
  2052   real_of_int_minus    reversed direction of equality (use [symmetric])
  2053   real_of_int_diff     reversed direction of equality (use [symmetric])
  2054   real_of_int_mult     reversed direction of equality (use [symmetric])
  2055 
  2056 * Theory RComplete: expanded support for floor and ceiling functions.
  2057 
  2058 * Theory Ln is new, with properties of the natural logarithm
  2059 
  2060 * Hyperreal: There is a new type constructor "star" for making
  2061 nonstandard types.  The old type names are now type synonyms:
  2062 
  2063   hypreal = real star
  2064   hypnat = nat star
  2065   hcomplex = complex star
  2066 
  2067 * Hyperreal: Many groups of similarly-defined constants have been
  2068 replaced by polymorphic versions (INCOMPATIBILITY):
  2069 
  2070   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2071 
  2072   starset      <-- starsetNat, starsetC
  2073   *s*          <-- *sNat*, *sc*
  2074   starset_n    <-- starsetNat_n, starsetC_n
  2075   *sn*         <-- *sNatn*, *scn*
  2076   InternalSets <-- InternalNatSets, InternalCSets
  2077 
  2078   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2079   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2080   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2081   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2082   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2083 
  2084 * Hyperreal: Many type-specific theorems have been removed in favor of
  2085 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2086 
  2087   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2088   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2089   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2090   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2091   right_minus <-- hypreal_add_minus
  2092   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2093   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2094   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2095   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2096   mult_1_right <-- hcomplex_mult_one_right
  2097   mult_zero_left <-- hcomplex_mult_zero_left
  2098   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2099   right_distrib <-- hypnat_add_mult_distrib2
  2100   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2101   right_inverse <-- hypreal_mult_inverse
  2102   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2103   order_refl <-- {hypreal,hypnat}_le_refl
  2104   order_trans <-- {hypreal,hypnat}_le_trans
  2105   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2106   order_less_le <-- {hypreal,hypnat}_less_le
  2107   linorder_linear <-- {hypreal,hypnat}_le_linear
  2108   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2109   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2110   add_nonneg_nonneg <-- hypreal_le_add_order
  2111 
  2112 * Hyperreal: Separate theorems having to do with type-specific
  2113 versions of constants have been merged into theorems that apply to the
  2114 new polymorphic constants (INCOMPATIBILITY):
  2115 
  2116   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2117   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2118   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2119   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2120   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2121   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2122   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2123   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2124   STAR_diff <-- {STAR,STARC}_diff
  2125   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2126     STARC_hcomplex_of_complex}_image_subset
  2127   starset_n_Un <-- starset{Nat,C}_n_Un
  2128   starset_n_Int <-- starset{Nat,C}_n_Int
  2129   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2130   starset_n_diff <-- starset{Nat,C}_n_diff
  2131   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2132   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2133   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2134   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2135   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2136   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2137   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2138   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2139   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2140   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2141   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2142   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2143   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2144   starfun_diff <-- starfun{C,RC,CR}_diff
  2145   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2146   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2147   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2148   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2149   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2150   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2151   starfun_Id <-- starfunC_Id
  2152   starfun_approx <-- starfun{Nat,CR}_approx
  2153   starfun_capprox <-- starfun{C,RC}_capprox
  2154   starfun_abs <-- starfunNat_rabs
  2155   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2156   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2157   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2158   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2159   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2160   starfun_add_approx <-- starfunCR_add_approx
  2161   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2162   starfun_divide <-- starfun{C,CR,RC}_divide
  2163   starfun_n <-- starfun{Nat,C}_n
  2164   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2165   starfun_n_add <-- starfun{Nat,C}_n_add
  2166   starfun_n_add_minus <-- starfunNat_n_add_minus
  2167   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2168   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2169   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2170 
  2171   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2172   star_n_minus <-- {hypreal,hcomplex}_minus
  2173   star_n_diff <-- {hypreal,hcomplex}_diff
  2174   star_n_mult <-- {hypreal,hcomplex}_mult
  2175   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2176   star_n_le <-- {hypreal,hypnat}_le
  2177   star_n_less <-- {hypreal,hypnat}_less
  2178   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2179   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2180   star_n_abs <-- hypreal_hrabs
  2181   star_n_divide <-- hcomplex_divide
  2182 
  2183   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2184   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2185   star_of_diff <-- hypreal_of_real_diff
  2186   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2187   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2188   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2189   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2190   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2191   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2192   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2193   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2194   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2195   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2196   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2197   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2198   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2199   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2200   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2201   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2202   star_of_power <-- hypreal_of_real_power
  2203   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2204 
  2205 * Hyperreal: new method "transfer" that implements the transfer
  2206 principle of nonstandard analysis. With a subgoal that mentions
  2207 nonstandard types like "'a star", the command "apply transfer"
  2208 replaces it with an equivalent one that mentions only standard types.
  2209 To be successful, all free variables must have standard types; non-
  2210 standard variables must have explicit universal quantifiers.
  2211 
  2212 * Hyperreal: A theory of Taylor series.
  2213 
  2214 
  2215 *** HOLCF ***
  2216 
  2217 * Discontinued special version of 'constdefs' (which used to support
  2218 continuous functions) in favor of the general Pure one with full
  2219 type-inference.
  2220 
  2221 * New simplification procedure for solving continuity conditions; it
  2222 is much faster on terms with many nested lambda abstractions (cubic
  2223 instead of exponential time).
  2224 
  2225 * New syntax for domain package: selector names are now optional.
  2226 Parentheses should be omitted unless argument is lazy, for example:
  2227 
  2228   domain 'a stream = cons "'a" (lazy "'a stream")
  2229 
  2230 * New command 'fixrec' for defining recursive functions with pattern
  2231 matching; defining multiple functions with mutual recursion is also
  2232 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2233 sinr, or any data constructor defined by the domain package. The given
  2234 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2235 syntax and examples.
  2236 
  2237 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2238 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2239 but the proof obligation additionally includes an admissibility
  2240 requirement. The packages generate instances of class cpo or pcpo,
  2241 with continuity and strictness theorems for Rep and Abs.
  2242 
  2243 * HOLCF: Many theorems have been renamed according to a more standard naming
  2244 scheme (INCOMPATIBILITY):
  2245 
  2246   foo_inject:  "foo$x = foo$y ==> x = y"
  2247   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2248   foo_less:    "(foo$x << foo$y) = (x << y)"
  2249   foo_strict:  "foo$UU = UU"
  2250   foo_defined: "... ==> foo$x ~= UU"
  2251   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2252 
  2253 
  2254 *** ZF ***
  2255 
  2256 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2257 including the First Isomorphism Theorem (on quotienting by the kernel
  2258 of a homomorphism).
  2259 
  2260 * ZF/Simplifier: install second copy of type solver that actually
  2261 makes use of TC rules declared to Isar proof contexts (or locales);
  2262 the old version is still required for ML proof scripts.
  2263 
  2264 
  2265 *** Cube ***
  2266 
  2267 * Converted to Isar theory format; use locales instead of axiomatic
  2268 theories.
  2269 
  2270 
  2271 *** ML ***
  2272 
  2273 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2274 for ||>, ||>>, |>>,
  2275 
  2276 * Pure/library.ML no longer defines its own option datatype, but uses
  2277 that of the SML basis, which has constructors NONE and SOME instead of
  2278 None and Some, as well as exception Option.Option instead of OPTION.
  2279 The functions the, if_none, is_some, is_none have been adapted
  2280 accordingly, while Option.map replaces apsome.
  2281 
  2282 * Pure/library.ML: the exception LIST has been given up in favour of
  2283 the standard exceptions Empty and Subscript, as well as
  2284 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2285 superceded by the standard hd and tl functions etc.
  2286 
  2287 A number of basic list functions are no longer exported to the ML
  2288 toplevel, as they are variants of predefined functions.  The following
  2289 suggests how one can translate existing code:
  2290 
  2291     rev_append xs ys = List.revAppend (xs, ys)
  2292     nth_elem (i, xs) = List.nth (xs, i)
  2293     last_elem xs = List.last xs
  2294     flat xss = List.concat xss
  2295     seq fs = List.app fs
  2296     partition P xs = List.partition P xs
  2297     mapfilter f xs = List.mapPartial f xs
  2298 
  2299 * Pure/library.ML: several combinators for linear functional
  2300 transformations, notably reverse application and composition:
  2301 
  2302   x |> f                f #> g
  2303   (x, y) |-> f          f #-> g
  2304 
  2305 * Pure/library.ML: introduced/changed precedence of infix operators:
  2306 
  2307   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2308   infix 2 ?;
  2309   infix 3 o oo ooo oooo;
  2310   infix 4 ~~ upto downto;
  2311 
  2312 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2313 infix operators.
  2314 
  2315 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2316 fold_map support linear functional transformations and nesting.  For
  2317 example:
  2318 
  2319   fold f [x1, ..., xN] y =
  2320     y |> f x1 |> ... |> f xN
  2321 
  2322   (fold o fold) f [xs1, ..., xsN] y =
  2323     y |> fold f xs1 |> ... |> fold f xsN
  2324 
  2325   fold f [x1, ..., xN] =
  2326     f x1 #> ... #> f xN
  2327 
  2328   (fold o fold) f [xs1, ..., xsN] =
  2329     fold f xs1 #> ... #> fold f xsN
  2330 
  2331 * Pure/library.ML: the following selectors on type 'a option are
  2332 available:
  2333 
  2334   the:               'a option -> 'a  (*partial*)
  2335   these:             'a option -> 'a  where 'a = 'b list
  2336   the_default: 'a -> 'a option -> 'a
  2337   the_list:          'a option -> 'a list
  2338 
  2339 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2340 basic operations for association lists, following natural argument
  2341 order; moreover the explicit equality predicate passed here avoids
  2342 potentially expensive polymorphic runtime equality checks.
  2343 The old functions may be expressed as follows:
  2344 
  2345   assoc = uncurry (AList.lookup (op =))
  2346   assocs = these oo AList.lookup (op =)
  2347   overwrite = uncurry (AList.update (op =)) o swap
  2348 
  2349 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2350 
  2351   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2352   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2353 
  2354 replacing make_keylist and keyfilter (occassionally used)
  2355 Naive rewrites:
  2356 
  2357   make_keylist = AList.make
  2358   keyfilter = AList.find (op =)
  2359 
  2360 * eq_fst and eq_snd now take explicit equality parameter, thus
  2361   avoiding eqtypes. Naive rewrites:
  2362 
  2363     eq_fst = eq_fst (op =)
  2364     eq_snd = eq_snd (op =)
  2365 
  2366 * Removed deprecated apl and apr (rarely used).
  2367   Naive rewrites:
  2368 
  2369     apl (n, op) =>>= curry op n
  2370     apr (op, m) =>>= fn n => op (n, m)
  2371 
  2372 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2373 provides a reasonably efficient light-weight implementation of sets as
  2374 lists.
  2375 
  2376 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2377 few new operations; existing lookup and update are now curried to
  2378 follow natural argument order (for use with fold etc.);
  2379 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2380 
  2381 * Pure/General: output via the Isabelle channels of
  2382 writeln/warning/error etc. is now passed through Output.output, with a
  2383 hook for arbitrary transformations depending on the print_mode
  2384 (cf. Output.add_mode -- the first active mode that provides a output
  2385 function wins).  Already formatted output may be embedded into further
  2386 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2387 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2388 accommodate easy composition of diagnostic messages etc.  Programmers
  2389 rarely need to care about Output.output or Output.raw at all, with
  2390 some notable exceptions: Output.output is required when bypassing the
  2391 standard channels (writeln etc.), or in token translations to produce
  2392 properly formatted results; Output.raw is required when capturing
  2393 already output material that will eventually be presented to the user
  2394 a second time.  For the default print mode, both Output.output and
  2395 Output.raw have no effect.
  2396 
  2397 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2398 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2399 cumulative results are displayed at the end of a batch session.
  2400 
  2401 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2402 replaced by File.platform_path and File.shell_path (with appropriate
  2403 hooks).  This provides a clean interface for unusual systems where the
  2404 internal and external process view of file names are different.
  2405 
  2406 * Pure: more efficient orders for basic syntactic entities: added
  2407 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2408 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2409 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2410 orders now -- potential INCOMPATIBILITY for code that depends on a
  2411 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2412 Library.sort_strings on result).
  2413 
  2414 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2415 fold_types traverse types/terms from left to right, observing natural
  2416 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2417 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2418 
  2419 * Pure: name spaces have been refined, with significant changes of the
  2420 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2421 to extern(_table).  The plain name entry path is superceded by a
  2422 general 'naming' context, which also includes the 'policy' to produce
  2423 a fully qualified name and external accesses of a fully qualified
  2424 name; NameSpace.extend is superceded by context dependent
  2425 Sign.declare_name.  Several theory and proof context operations modify
  2426 the naming context.  Especially note Theory.restore_naming and
  2427 ProofContext.restore_naming to get back to a sane state; note that
  2428 Theory.add_path is no longer sufficient to recover from
  2429 Theory.absolute_path in particular.
  2430 
  2431 * Pure: new flags short_names (default false) and unique_names
  2432 (default true) for controlling output of qualified names.  If
  2433 short_names is set, names are printed unqualified.  If unique_names is
  2434 reset, the name prefix is reduced to the minimum required to achieve
  2435 the original result when interning again, even if there is an overlap
  2436 with earlier declarations.
  2437 
  2438 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2439 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2440 (useful for printing error messages).  INCOMPATIBILITY.
  2441 
  2442 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2443 Theory.theory are now identified, referring to the universal
  2444 Context.theory (see Pure/context.ML).  Actual signature and theory
  2445 content is managed as theory data.  The old code and interfaces were
  2446 spread over many files and structures; the new arrangement introduces
  2447 considerable INCOMPATIBILITY to gain more clarity:
  2448 
  2449   Context -- theory management operations (name, identity, inclusion,
  2450     parents, ancestors, merge, etc.), plus generic theory data;
  2451 
  2452   Sign -- logical signature and syntax operations (declaring consts,
  2453     types, etc.), plus certify/read for common entities;
  2454 
  2455   Theory -- logical theory operations (stating axioms, definitions,
  2456     oracles), plus a copy of logical signature operations (consts,
  2457     types, etc.); also a few basic management operations (Theory.copy,
  2458     Theory.merge, etc.)
  2459 
  2460 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  2461 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  2462 for convenience -- they merely return the theory.
  2463 
  2464 * Pure: type Type.tsig is superceded by theory in most interfaces.
  2465 
  2466 * Pure: the Isar proof context type is already defined early in Pure
  2467 as Context.proof (note that ProofContext.context and Proof.context are
  2468 aliases, where the latter is the preferred name).  This enables other
  2469 Isabelle components to refer to that type even before Isar is present.
  2470 
  2471 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  2472 typeK, constK, axiomK, oracleK), but provide explicit operations for
  2473 any of these kinds.  For example, Sign.intern typeK is now
  2474 Sign.intern_type, Theory.hide_space Sign.typeK is now
  2475 Theory.hide_types.  Also note that former
  2476 Theory.hide_classes/types/consts are now
  2477 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  2478 internalize their arguments!  INCOMPATIBILITY.
  2479 
  2480 * Pure: get_thm interface (of PureThy and ProofContext) expects
  2481 datatype thmref (with constructors Name and NameSelection) instead of
  2482 plain string -- INCOMPATIBILITY;
  2483 
  2484 * Pure: cases produced by proof methods specify options, where NONE
  2485 means to remove case bindings -- INCOMPATIBILITY in
  2486 (RAW_)METHOD_CASES.
  2487 
  2488 * Pure: the following operations retrieve axioms or theorems from a
  2489 theory node or theory hierarchy, respectively:
  2490 
  2491   Theory.axioms_of: theory -> (string * term) list
  2492   Theory.all_axioms_of: theory -> (string * term) list
  2493   PureThy.thms_of: theory -> (string * thm) list
  2494   PureThy.all_thms_of: theory -> (string * thm) list
  2495 
  2496 * Pure: print_tac now outputs the goal through the trace channel.
  2497 
  2498 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  2499 Reference Toplevel.debug (default false) controls detailed printing
  2500 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  2501 controls execution profiling -- set to 1 for time and 2 for space
  2502 (both increase the runtime).
  2503 
  2504 * Isar session: The initial use of ROOT.ML is now always timed,
  2505 i.e. the log will show the actual process times, in contrast to the
  2506 elapsed wall-clock time that the outer shell wrapper produces.
  2507 
  2508 * Simplifier: improved handling of bound variables (nameless
  2509 representation, avoid allocating new strings).  Simprocs that invoke
  2510 the Simplifier recursively should use Simplifier.inherit_bounds to
  2511 avoid local name clashes.  Failure to do so produces warnings
  2512 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  2513 for further details.
  2514 
  2515 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  2516 bindings for all theorems stored within a given theory; this may help
  2517 in porting non-Isar theories to Isar ones, while keeping ML proof
  2518 scripts for the time being.
  2519 
  2520 * ML operator HTML.with_charset specifies the charset begin used for
  2521 generated HTML files.  For example:
  2522 
  2523   HTML.with_charset "utf-8" use_thy "Hebrew";
  2524   HTML.with_charset "utf-8" use_thy "Chinese";
  2525 
  2526 
  2527 *** System ***
  2528 
  2529 * Allow symlinks to all proper Isabelle executables (Isabelle,
  2530 isabelle, isatool etc.).
  2531 
  2532 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  2533 isatool doc, isatool mkdir, display_drafts etc.).
  2534 
  2535 * isatool usedir: option -f allows specification of the ML file to be
  2536 used by Isabelle; default is ROOT.ML.
  2537 
  2538 * New isatool version outputs the version identifier of the Isabelle
  2539 distribution being used.
  2540 
  2541 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  2542 (containing Boolean satisfiability problems) into Isabelle/HOL
  2543 theories.
  2544 
  2545 
  2546 
  2547 New in Isabelle2004 (April 2004)
  2548 --------------------------------
  2549 
  2550 *** General ***
  2551 
  2552 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  2553   Replaces linorder.ML.
  2554 
  2555 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  2556   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  2557   (\<a>...\<z>), are now considered normal letters, and can therefore
  2558   be used anywhere where an ASCII letter (a...zA...Z) has until
  2559   now. COMPATIBILITY: This obviously changes the parsing of some
  2560   terms, especially where a symbol has been used as a binder, say
  2561   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  2562   as an identifier.  Fix it by inserting a space around former
  2563   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  2564   existing theory and ML files.
  2565 
  2566 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  2567 
  2568 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  2569   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  2570   a normal (but invisible) letter. For multiple letter subscripts repeat
  2571   \<^isub> like this: x\<^isub>1\<^isub>2.
  2572 
  2573 * Pure: There are now sub-/superscripts that can span more than one
  2574   character. Text between \<^bsub> and \<^esub> is set in subscript in
  2575   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  2576   superscript. The new control characters are not identifier parts.
  2577 
  2578 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  2579   content of "..." to the latex file instead of \isacntrl... . The "..."
  2580   may consist of any printable characters excluding the end bracket >.
  2581 
  2582 * Pure: Using new Isar command "finalconsts" (or the ML functions
  2583   Theory.add_finals or Theory.add_finals_i) it is now possible to
  2584   declare constants "final", which prevents their being given a definition
  2585   later.  It is useful for constants whose behaviour is fixed axiomatically
  2586   rather than definitionally, such as the meta-logic connectives.
  2587 
  2588 * Pure: 'instance' now handles general arities with general sorts
  2589   (i.e. intersections of classes),
  2590 
  2591 * Presentation: generated HTML now uses a CSS style sheet to make layout
  2592   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  2593   It can be changed to alter the colors/layout of generated pages.
  2594 
  2595 
  2596 *** Isar ***
  2597 
  2598 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  2599   cut_tac, subgoal_tac and thin_tac:
  2600   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  2601     locales are no longer forced to write Isar proof scripts.
  2602     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  2603     emulations.
  2604   - INCOMPATIBILITY: names of variables to be instantiated may no
  2605     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  2606     This is consistent with the instantiation attribute "where".
  2607 
  2608 * Attributes "where" and "of":
  2609   - Now take type variables of instantiated theorem into account when reading
  2610     the instantiation string.  This fixes a bug that caused instantiated
  2611     theorems to have too special types in some circumstances.
  2612   - "where" permits explicit instantiations of type variables.
  2613 
  2614 * Calculation commands "moreover" and "also" no longer interfere with
  2615   current facts ("this"), admitting arbitrary combinations with "then"
  2616   and derived forms.
  2617 
  2618 * Locales:
  2619   - Goal statements involving the context element "includes" no longer
  2620     generate theorems with internal delta predicates (those ending on
  2621     "_axioms") in the premise.
  2622     Resolve particular premise with <locale>.intro to obtain old form.
  2623   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  2624     specification and "includes" elements in goal statement.
  2625   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  2626     [intro?] and [elim?] (respectively) by default.
  2627   - Experimental command for instantiation of locales in proof contexts:
  2628         instantiate <label>[<attrs>]: <loc>
  2629     Instantiates locale <loc> and adds all its theorems to the current context
  2630     taking into account their attributes.  Label and attrs are optional
  2631     modifiers, like in theorem declarations.  If present, names of
  2632     instantiated theorems are qualified with <label>, and the attributes
  2633     <attrs> are applied after any attributes these theorems might have already.
  2634       If the locale has assumptions, a chained fact of the form
  2635     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  2636     are derived.  The command does not support old-style locales declared
  2637     with "locale (open)".
  2638       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  2639 
  2640 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  2641   (Isar) contexts.
  2642 
  2643 
  2644 *** HOL ***
  2645 
  2646 * Proof import: new image HOL4 contains the imported library from
  2647   the HOL4 system with about 2500 theorems. It is imported by
  2648   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  2649   can be used like any other Isabelle image.  See
  2650   HOL/Import/HOL/README for more information.
  2651 
  2652 * Simplifier:
  2653   - Much improved handling of linear and partial orders.
  2654     Reasoners for linear and partial orders are set up for type classes
  2655     "linorder" and "order" respectively, and are added to the default simpset
  2656     as solvers.  This means that the simplifier can build transitivity chains
  2657     to solve goals from the assumptions.
  2658   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  2659     of blast or auto after simplification become unnecessary because the goal
  2660     is solved by simplification already.
  2661 
  2662 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  2663     all proved in axiomatic type classes for semirings, rings and fields.
  2664 
  2665 * Numerics:
  2666   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  2667     now formalized using the Ring_and_Field theory mentioned above.
  2668   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  2669     than before, because now they are set up once in a generic manner.
  2670   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  2671     Look for the general versions in Ring_and_Field (and Power if they concern
  2672     exponentiation).
  2673 
  2674 * Type "rat" of the rational numbers is now available in HOL-Complex.
  2675 
  2676 * Records:
  2677   - Record types are now by default printed with their type abbreviation
  2678     instead of the list of all field types. This can be configured via
  2679     the reference "print_record_type_abbr".
  2680   - Simproc "record_upd_simproc" for simplification of multiple updates added
  2681     (not enabled by default).
  2682   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  2683     EX x. x = sel r to True (not enabled by default).
  2684   - Tactic "record_split_simp_tac" to split and simplify records added.
  2685 
  2686 * 'specification' command added, allowing for definition by
  2687   specification.  There is also an 'ax_specification' command that
  2688   introduces the new constants axiomatically.
  2689 
  2690 * arith(_tac) is now able to generate counterexamples for reals as well.
  2691 
  2692 * HOL-Algebra: new locale "ring" for non-commutative rings.
  2693 
  2694 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  2695   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  2696 
  2697 * HOL-Matrix: a first theory for matrices in HOL with an application of
  2698   matrix theory to linear programming.
  2699 
  2700 * Unions and Intersections:
  2701   The latex output syntax of UN and INT has been changed
  2702   from "\Union x \in A. B" to "\Union_{x \in A} B"
  2703   i.e. the index formulae has become a subscript.
  2704   Similarly for "\Union x. B", and for \Inter instead of \Union.
  2705 
  2706 * Unions and Intersections over Intervals:
  2707   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  2708   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  2709   like in normal math, and corresponding versions for < and for intersection.
  2710 
  2711 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  2712   lexicographic dictonary ordering has been added as "lexord".
  2713 
  2714 * ML: the legacy theory structures Int and List have been removed. They had
  2715   conflicted with ML Basis Library structures having the same names.
  2716 
  2717 * 'refute' command added to search for (finite) countermodels.  Only works
  2718   for a fragment of HOL.  The installation of an external SAT solver is
  2719   highly recommended.  See "HOL/Refute.thy" for details.
  2720 
  2721 * 'quickcheck' command: Allows to find counterexamples by evaluating
  2722   formulae under an assignment of free variables to random values.
  2723   In contrast to 'refute', it can deal with inductive datatypes,
  2724   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  2725   for examples.
  2726 
  2727 
  2728 *** HOLCF ***
  2729 
  2730 * Streams now come with concatenation and are part of the HOLCF image
  2731 
  2732 
  2733 
  2734 New in Isabelle2003 (May 2003)
  2735 ------------------------------
  2736 
  2737 *** General ***
  2738 
  2739 * Provers/simplifier:
  2740 
  2741   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  2742     Assumptions are now subject to complete mutual simplification,
  2743     not just from left to right. The simplifier now preserves
  2744     the order of assumptions.
  2745 
  2746     Potential INCOMPATIBILITY:
  2747 
  2748     -- simp sometimes diverges where the old version did
  2749        not, e.g. invoking simp on the goal
  2750 
  2751         [| P (f x); y = x; f x = f y |] ==> Q
  2752 
  2753        now gives rise to the infinite reduction sequence
  2754 
  2755         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  2756 
  2757        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  2758        kind of problem.
  2759 
  2760     -- Tactics combining classical reasoner and simplification (such as auto)
  2761        are also affected by this change, because many of them rely on
  2762        simp. They may sometimes diverge as well or yield a different numbers
  2763        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  2764        in case of problems. Sometimes subsequent calls to the classical
  2765        reasoner will fail because a preceeding call to the simplifier too
  2766        eagerly simplified the goal, e.g. deleted redundant premises.
  2767 
  2768   - The simplifier trace now shows the names of the applied rewrite rules
  2769 
  2770   - You can limit the number of recursive invocations of the simplifier
  2771     during conditional rewriting (where the simplifie tries to solve the
  2772     conditions before applying the rewrite rule):
  2773     ML "simp_depth_limit := n"
  2774     where n is an integer. Thus you can force termination where previously
  2775     the simplifier would diverge.
  2776 
  2777   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  2778 
  2779   - No longer aborts on failed congruence proof.  Instead, the
  2780     congruence is ignored.
  2781 
  2782 * Pure: New generic framework for extracting programs from constructive
  2783   proofs. See HOL/Extraction.thy for an example instantiation, as well
  2784   as HOL/Extraction for some case studies.
  2785 
  2786 * Pure: The main goal of the proof state is no longer shown by default, only
  2787 the subgoals. This behaviour is controlled by a new flag.
  2788    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  2789 (ML: Proof.show_main_goal).
  2790 
  2791 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  2792 rules whose conclusion matches subgoal 1:
  2793       PG menu: Isabelle/Isar -> Show me -> matching rules
  2794 The rules are ordered by how closely they match the subgoal.
  2795 In particular, rules that solve a subgoal outright are displayed first
  2796 (or rather last, the way they are printed).
  2797 (ML: ProofGeneral.print_intros())
  2798 
  2799 * Pure: New flag trace_unify_fail causes unification to print
  2800 diagnostic information (PG: in trace buffer) when it fails. This is
  2801 useful for figuring out why single step proofs like rule, erule or
  2802 assumption failed.
  2803 
  2804 * Pure: Locale specifications now produce predicate definitions
  2805 according to the body of text (covering assumptions modulo local
  2806 definitions); predicate "loc_axioms" covers newly introduced text,
  2807 while "loc" is cumulative wrt. all included locale expressions; the
  2808 latter view is presented only on export into the global theory
  2809 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  2810 on the old view without predicates;
  2811 
  2812 * Pure: predefined locales "var" and "struct" are useful for sharing
  2813 parameters (as in CASL, for example); just specify something like
  2814 ``var x + var y + struct M'' as import;
  2815 
  2816 * Pure: improved thms_containing: proper indexing of facts instead of
  2817 raw theorems; check validity of results wrt. current name space;
  2818 include local facts of proof configuration (also covers active
  2819 locales), cover fixed variables in index; may use "_" in term
  2820 specification; an optional limit for the number of printed facts may
  2821 be given (the default is 40);
  2822 
  2823 * Pure: disallow duplicate fact bindings within new-style theory files
  2824 (batch-mode only);
  2825 
  2826 * Provers: improved induct method: assumptions introduced by case
  2827 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  2828 the goal statement); "foo" still refers to all facts collectively;
  2829 
  2830 * Provers: the function blast.overloaded has been removed: all constants
  2831 are regarded as potentially overloaded, which improves robustness in exchange
  2832 for slight decrease in efficiency;
  2833 
  2834 * Provers/linorder: New generic prover for transitivity reasoning over
  2835 linear orders.  Note: this prover is not efficient!
  2836 
  2837 * Isar: preview of problems to finish 'show' now produce an error
  2838 rather than just a warning (in interactive mode);
  2839 
  2840 
  2841 *** HOL ***
  2842 
  2843 * arith(_tac)
  2844 
  2845  - Produces a counter example if it cannot prove a goal.
  2846    Note that the counter example may be spurious if the goal is not a formula
  2847    of quantifier-free linear arithmetic.
  2848    In ProofGeneral the counter example appears in the trace buffer.
  2849 
  2850  - Knows about div k and mod k where k is a numeral of type nat or int.
  2851 
  2852  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  2853    linear arithmetic fails. This takes account of quantifiers and divisibility.
  2854    Presburger arithmetic can also be called explicitly via presburger(_tac).
  2855 
  2856 * simp's arithmetic capabilities have been enhanced a bit: it now
  2857 takes ~= in premises into account (by performing a case split);
  2858 
  2859 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  2860 are distributed over a sum of terms;
  2861 
  2862 * New tactic "trans_tac" and method "trans" instantiate
  2863 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  2864 "<=", "<" and "=").
  2865 
  2866 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  2867 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  2868 
  2869 * 'typedef' command has new option "open" to suppress the set
  2870 definition;
  2871 
  2872 * functions Min and Max on finite sets have been introduced (theory
  2873 Finite_Set);
  2874 
  2875 * attribute [symmetric] now works for relations as well; it turns
  2876 (x,y) : R^-1 into (y,x) : R, and vice versa;
  2877 
  2878 * induct over a !!-quantified statement (say !!x1..xn):
  2879   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  2880 
  2881 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  2882 %x. None. Warning: empty_def now refers to the previously hidden definition
  2883 of the empty set.
  2884 
  2885 * Algebra: formalization of classical algebra.  Intended as base for
  2886 any algebraic development in Isabelle.  Currently covers group theory
  2887 (up to Sylow's theorem) and ring theory (Universal Property of
  2888 Univariate Polynomials).  Contributions welcome;
  2889 
  2890 * GroupTheory: deleted, since its material has been moved to Algebra;
  2891 
  2892 * Complex: new directory of the complex numbers with numeric constants,
  2893 nonstandard complex numbers, and some complex analysis, standard and
  2894 nonstandard (Jacques Fleuriot);
  2895 
  2896 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  2897 
  2898 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  2899 Fleuriot);
  2900 
  2901 * Real/HahnBanach: updated and adapted to locales;
  2902 
  2903 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  2904 Gray and Kramer);
  2905 
  2906 * UNITY: added the Meier-Sanders theory of progress sets;
  2907 
  2908 * MicroJava: bytecode verifier and lightweight bytecode verifier
  2909 as abstract algorithms, instantiated to the JVM;
  2910 
  2911 * Bali: Java source language formalization. Type system, operational
  2912 semantics, axiomatic semantics. Supported language features:
  2913 classes, interfaces, objects,virtual methods, static methods,
  2914 static/instance fields, arrays, access modifiers, definite
  2915 assignment, exceptions.
  2916 
  2917 
  2918 *** ZF ***
  2919 
  2920 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  2921 universe, etc.);
  2922 
  2923 * Main ZF: virtually all theories converted to new-style format;
  2924 
  2925 
  2926 *** ML ***
  2927 
  2928 * Pure: Tactic.prove provides sane interface for internal proofs;
  2929 omits the infamous "standard" operation, so this is more appropriate
  2930 than prove_goalw_cterm in many situations (e.g. in simprocs);
  2931 
  2932 * Pure: improved error reporting of simprocs;
  2933 
  2934 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  2935 up simprocs;
  2936 
  2937 
  2938 *** Document preparation ***
  2939 
  2940 * uses \par instead of \\ for line breaks in theory text. This may
  2941 shift some page breaks in large documents. To get the old behaviour
  2942 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  2943 
  2944 * minimized dependencies of isabelle.sty and isabellesym.sty on
  2945 other packages
  2946 
  2947 * \<euro> now needs package babel/greek instead of marvosym (which
  2948 broke \Rightarrow)
  2949 
  2950 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  2951 textcomp package)
  2952 
  2953 
  2954 
  2955 New in Isabelle2002 (March 2002)
  2956 --------------------------------
  2957 
  2958 *** Document preparation ***
  2959 
  2960 * greatly simplified document preparation setup, including more
  2961 graceful interpretation of isatool usedir -i/-d/-D options, and more
  2962 instructive isatool mkdir; users should basically be able to get
  2963 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  2964 users may run a separate document processing stage manually like this:
  2965 "isatool usedir -D output HOL Test && isatool document Test/output";
  2966 
  2967 * theory dependency graph may now be incorporated into documents;
  2968 isatool usedir -g true will produce session_graph.eps/.pdf for use
  2969 with \includegraphics of LaTeX;
  2970 
  2971 * proper spacing of consecutive markup elements, especially text
  2972 blocks after section headings;
  2973 
  2974 * support bold style (for single symbols only), input syntax is like
  2975 this: "\<^bold>\<alpha>" or "\<^bold>A";
  2976 
  2977 * \<bullet> is now output as bold \cdot by default, which looks much
  2978 better in printed text;
  2979 
  2980 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  2981 note that these symbols are currently unavailable in Proof General /
  2982 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  2983 
  2984 * isatool latex no longer depends on changed TEXINPUTS, instead
  2985 isatool document copies the Isabelle style files to the target
  2986 location;
  2987 
  2988 
  2989 *** Isar ***
  2990 
  2991 * Pure/Provers: improved proof by cases and induction;
  2992   - 'case' command admits impromptu naming of parameters (such as
  2993     "case (Suc n)");
  2994   - 'induct' method divinates rule instantiation from the inductive
  2995     claim; no longer requires excessive ?P bindings for proper
  2996     instantiation of cases;
  2997   - 'induct' method properly enumerates all possibilities of set/type
  2998     rules; as a consequence facts may be also passed through *type*
  2999     rules without further ado;
  3000   - 'induct' method now derives symbolic cases from the *rulified*
  3001     rule (before it used to rulify cases stemming from the internal
  3002     atomized version); this means that the context of a non-atomic
  3003     statement becomes is included in the hypothesis, avoiding the
  3004     slightly cumbersome show "PROP ?case" form;
  3005   - 'induct' may now use elim-style induction rules without chaining
  3006     facts, using ``missing'' premises from the goal state; this allows
  3007     rules stemming from inductive sets to be applied in unstructured
  3008     scripts, while still benefitting from proper handling of non-atomic
  3009     statements; NB: major inductive premises need to be put first, all
  3010     the rest of the goal is passed through the induction;
  3011   - 'induct' proper support for mutual induction involving non-atomic
  3012     rule statements (uses the new concept of simultaneous goals, see
  3013     below);
  3014   - append all possible rule selections, but only use the first
  3015     success (no backtracking);
  3016   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3017   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3018   - added 'print_induct_rules' (covered by help item in recent Proof
  3019     General versions);
  3020   - moved induct/cases attributes to Pure, methods to Provers;
  3021   - generic method setup instantiated for FOL and HOL;
  3022 
  3023 * Pure: support multiple simultaneous goal statements, for example
  3024 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3025 meta-level mechanism, this acts as if several individual goals had
  3026 been stated separately; in particular common proof methods need to be
  3027 repeated in order to cover all claims; note that a single elimination
  3028 step is *not* sufficient to establish the two conjunctions, so this
  3029 fails:
  3030 
  3031   assume "A & B" then have A and B ..   (*".." fails*)
  3032 
  3033 better use "obtain" in situations as above; alternative refer to
  3034 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3035 
  3036 * Pure: proper integration with ``locales''; unlike the original
  3037 version by Florian Kammller, Isar locales package high-level proof
  3038 contexts rather than raw logical ones (e.g. we admit to include
  3039 attributes everywhere); operations on locales include merge and
  3040 rename; support for implicit arguments (``structures''); simultaneous
  3041 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3042 some examples;
  3043 
  3044 * Pure: the following commands have been ``localized'', supporting a
  3045 target locale specification "(in name)": 'lemma', 'theorem',
  3046 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3047 stored both within the locale and at the theory level (exported and
  3048 qualified by the locale name);
  3049 
  3050 * Pure: theory goals may now be specified in ``long'' form, with
  3051 ad-hoc contexts consisting of arbitrary locale elements. for example
  3052 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3053 definitions may be given, too); the result is a meta-level rule with
  3054 the context elements being discharged in the obvious way;
  3055 
  3056 * Pure: new proof command 'using' allows to augment currently used
  3057 facts after a goal statement ('using' is syntactically analogous to
  3058 'apply', but acts on the goal's facts only); this allows chained facts
  3059 to be separated into parts given before and after a claim, as in
  3060 ``from a and b have C using d and e <proof>'';
  3061 
  3062 * Pure: renamed "antecedent" case to "rule_context";
  3063 
  3064 * Pure: new 'judgment' command records explicit information about the
  3065 object-logic embedding (used by several tools internally); no longer
  3066 use hard-wired "Trueprop";
  3067 
  3068 * Pure: added 'corollary' command;
  3069 
  3070 * Pure: fixed 'token_translation' command;
  3071 
  3072 * Pure: removed obsolete 'exported' attribute;
  3073 
  3074 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3075 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3076 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3077 
  3078 * Pure: method 'atomize' presents local goal premises as object-level
  3079 statements (atomic meta-level propositions); setup controlled via
  3080 rewrite rules declarations of 'atomize' attribute; example
  3081 application: 'induct' method with proper rule statements in improper
  3082 proof *scripts*;
  3083 
  3084 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3085 now consider the syntactic context of assumptions, giving a better
  3086 chance to get type-inference of the arguments right (this is
  3087 especially important for locales);
  3088 
  3089 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3090 mode;
  3091 
  3092 * Pure/obtain: the formal conclusion "thesis", being marked as
  3093 ``internal'', may no longer be reference directly in the text;
  3094 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3095 situations;
  3096 
  3097 * Pure: generic 'sym' attribute which declares a rule both as pure
  3098 'elim?' and for the 'symmetric' operation;
  3099 
  3100 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3101 text; the fixed correlation with particular command syntax has been
  3102 discontinued;
  3103 
  3104 * Pure: new method 'rules' is particularly well-suited for proof
  3105 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3106 but often produces more compact proof terms with less detours;
  3107 
  3108 * Pure/Provers/classical: simplified integration with pure rule
  3109 attributes and methods; the classical "intro?/elim?/dest?"
  3110 declarations coincide with the pure ones; the "rule" method no longer
  3111 includes classically swapped intros; "intro" and "elim" methods no
  3112 longer pick rules from the context; also got rid of ML declarations
  3113 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3114 INCOMPATIBILITY;
  3115 
  3116 * Provers/classical: attribute 'swapped' produces classical inversions
  3117 of introduction rules;
  3118 
  3119 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3120 rules instead of full simplifier context; 'iff' attribute handles
  3121 conditional rules;
  3122 
  3123 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3124 
  3125 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3126 "(permissive)" option to recover old behavior;
  3127 
  3128 * HOL: 'inductive' no longer features separate (collective) attributes
  3129 for 'intros' (was found too confusing);
  3130 
  3131 * HOL: properly declared induction rules less_induct and
  3132 wf_induct_rule;
  3133 
  3134 
  3135 *** HOL ***
  3136 
  3137 * HOL: moved over to sane numeral syntax; the new policy is as
  3138 follows:
  3139 
  3140   - 0 and 1 are polymorphic constants, which are defined on any
  3141   numeric type (nat, int, real etc.);
  3142 
  3143   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3144   binary representation internally;
  3145 
  3146   - type nat has special constructor Suc, and generally prefers Suc 0
  3147   over 1::nat and Suc (Suc 0) over 2::nat;
  3148 
  3149 This change may cause significant problems of INCOMPATIBILITY; here
  3150 are some hints on converting existing sources:
  3151 
  3152   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3153   entities, so expressions involving "-" (unary or binary minus) need
  3154   to be spaced properly;
  3155 
  3156   - existing occurrences of "1" may need to be constraint "1::nat" or
  3157   even replaced by Suc 0; similar for old "2";
  3158 
  3159   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3160 
  3161   - remove all special provisions on numerals in proofs;
  3162 
  3163 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3164 representation (depends on bin_arith_simps in the default context);
  3165 
  3166 * HOL: symbolic syntax for x^2 (numeral 2);
  3167 
  3168 * HOL: the class of all HOL types is now called "type" rather than
  3169 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3170 in axclass/classes, instance/arities, and (usually rare) occurrences
  3171 in typings (of consts etc.); internally the class is called
  3172 "HOL.type", ML programs should refer to HOLogic.typeS;
  3173 
  3174 * HOL/record package improvements:
  3175   - new derived operations "fields" to build a partial record section,
  3176     "extend" to promote a fixed record to a record scheme, and
  3177     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3178     declared as simp by default;
  3179   - shared operations ("more", "fields", etc.) now need to be always
  3180     qualified) --- potential INCOMPATIBILITY;
  3181   - removed "make_scheme" operations (use "make" with "extend") --
  3182     INCOMPATIBILITY;
  3183   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3184   - provides cases/induct rules for use with corresponding Isar
  3185     methods (for concrete records, record schemes, concrete more
  3186     parts, and schematic more parts -- in that order);
  3187   - internal definitions directly based on a light-weight abstract
  3188     theory of product types over typedef rather than datatype;
  3189 
  3190 * HOL: generic code generator for generating executable ML code from
  3191 specifications; specific support for HOL constructs such as inductive
  3192 datatypes and sets, as well as recursive functions; can be invoked
  3193 via 'generate_code' theory section;
  3194 
  3195 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3196 
  3197 * HOL: consolidated and renamed several theories.  In particular:
  3198         Ord.thy has been absorbed into HOL.thy
  3199         String.thy has been absorbed into List.thy
  3200 
  3201 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3202 (beware of argument permutation!);
  3203 
  3204 * HOL: linorder_less_split superseded by linorder_cases;
  3205 
  3206 * HOL/List: "nodups" renamed to "distinct";
  3207 
  3208 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3209 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3210   - Ex_def has changed, now need to use some_eq_ex
  3211 
  3212 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3213 in this (rare) case use:
  3214 
  3215   delSWrapper "split_all_tac"
  3216   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3217 
  3218 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3219 MAY FAIL;
  3220 
  3221 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3222 Isabelle's type classes, ^ on functions and relations has too general
  3223 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3224 necessary to attach explicit type constraints;
  3225 
  3226 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3227 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3228 renamed accordingly (eg "compI" -> "rel_compI").
  3229 
  3230 * HOL: syntax translations now work properly with numerals and records
  3231 expressions;
  3232 
  3233 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3234 of "lam" -- INCOMPATIBILITY;
  3235 
  3236 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3237 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3238 renamed "Product_Type.unit";
  3239 
  3240 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3241 
  3242 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3243 the "cases" method);
  3244 
  3245 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3246 Florian Kammller);
  3247 
  3248 * HOL/IMP: updated and converted to new-style theory format; several
  3249 parts turned into readable document, with proper Isar proof texts and
  3250 some explanations (by Gerwin Klein);
  3251 
  3252 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3253 
  3254 * HOL-Hyperreal is now a logic image;
  3255 
  3256 
  3257 *** HOLCF ***
  3258 
  3259 * Isar: consts/constdefs supports mixfix syntax for continuous
  3260 operations;
  3261 
  3262 * Isar: domain package adapted to new-style theory format, e.g. see
  3263 HOLCF/ex/Dnat.thy;
  3264 
  3265 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3266 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3267 lift.induct_tac, always use UU instead of Undef;
  3268 
  3269 * HOLCF/IMP: updated and converted to new-style theory;
  3270 
  3271 
  3272 *** ZF ***
  3273 
  3274 * Isar: proper integration of logic-specific tools and packages,
  3275 including theory commands '(co)inductive', '(co)datatype',
  3276 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3277 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3278 
  3279 * theory Main no longer includes AC; for the Axiom of Choice, base
  3280 your theory on Main_ZFC;
  3281 
  3282 * the integer library now covers quotients and remainders, with many
  3283 laws relating division to addition, multiplication, etc.;
  3284 
  3285 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3286 typeless version of the formalism;
  3287 
  3288 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3289 format;
  3290 
  3291 * ZF/Induct: new directory for examples of inductive definitions,
  3292 including theory Multiset for multiset orderings; converted to
  3293 new-style theory format;
  3294 
  3295 * ZF: many new theorems about lists, ordinals, etc.;
  3296 
  3297 
  3298 *** General ***
  3299 
  3300 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3301 variable proof controls level of detail: 0 = no proofs (only oracle
  3302 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3303 also ref manual for further ML interfaces;
  3304 
  3305 * Pure/axclass: removed obsolete ML interface
  3306 goal_subclass/goal_arity;
  3307 
  3308 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3309 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3310 separate tokens, so expressions involving minus need to be spaced
  3311 properly;
  3312 
  3313 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3314 rather than "infixl" or "infixr";
  3315 
  3316 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3317 sort constraint specifications in type inference; e.g. "x::_::foo"
  3318 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3319 type variable);
  3320 
  3321 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3322 control output of nested => (types); the default behavior is
  3323 "type_brackets";
  3324 
  3325 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3326 tokens into AST constants;
  3327 
  3328 * Pure/syntax: prefer later declarations of translations and print
  3329 translation functions; potential INCOMPATIBILITY: need to reverse
  3330 multiple declarations for same syntax element constant;
  3331 
  3332 * Pure/show_hyps reset by default (in accordance to existing Isar
  3333 practice);
  3334 
  3335 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3336 addSafter;
  3337 
  3338 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3339 as well;
  3340 
  3341 * system: tested support for MacOS X; should be able to get Isabelle +
  3342 Proof General to work in a plain Terminal after installing Poly/ML
  3343 (e.g. from the Isabelle distribution area) and GNU bash alone
  3344 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3345 support requires further installations, e.g. from
  3346 http://fink.sourceforge.net/);
  3347 
  3348 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3349 
  3350 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3351 of 40 MB), cf. ML_OPTIONS;
  3352 
  3353 * system: Proof General keywords specification is now part of the
  3354 Isabelle distribution (see etc/isar-keywords.el);
  3355 
  3356 * system: support for persistent Proof General sessions (refrain from
  3357 outdating all loaded theories on startup); user may create writable
  3358 logic images like this: ``isabelle -q HOL Test'';
  3359 
  3360 * system: smart selection of Isabelle process versus Isabelle
  3361 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3362 run both "isabelle" and "Isabelle" even if file names are badly
  3363 damaged (executable inspects the case of the first letter of its own
  3364 name); added separate "isabelle-process" and "isabelle-interface";
  3365 
  3366 * system: refrain from any attempt at filtering input streams; no
  3367 longer support ``8bit'' encoding of old isabelle font, instead proper
  3368 iso-latin characters may now be used; the related isatools
  3369 "symbolinput" and "nonascii" have disappeared as well;
  3370 
  3371 * system: removed old "xterm" interface (the print modes "xterm" and
  3372 "xterm_color" are still available for direct use in a suitable
  3373 terminal);
  3374 
  3375 
  3376 
  3377 New in Isabelle99-2 (February 2001)
  3378 -----------------------------------
  3379 
  3380 *** Overview of INCOMPATIBILITIES ***
  3381 
  3382 * HOL: please note that theories in the Library and elsewhere often use the
  3383 new-style (Isar) format; to refer to their theorems in an ML script you must
  3384 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3385 
  3386 * HOL: inductive package no longer splits induction rule aggressively,
  3387 but only as far as specified by the introductions given; the old
  3388 format may be recovered via ML function complete_split_rule or attribute
  3389 'split_rule (complete)';
  3390 
  3391 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3392 gfp_Tarski to gfp_unfold;
  3393 
  3394 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3395 
  3396 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3397 relation); infix "^^" has been renamed "``"; infix "``" has been
  3398 renamed "`"; "univalent" has been renamed "single_valued";
  3399 
  3400 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3401 operation;
  3402 
  3403 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3404 
  3405 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3406 
  3407 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3408 consequence, it is no longer monotonic wrt. the local goal context
  3409 (which is now passed through the inductive cases);
  3410 
  3411 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3412 \<gg> to \<ggreater>;
  3413 
  3414 
  3415 *** Document preparation ***
  3416 
  3417 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3418 available: are "it" for near math-mode best-style output, "sl" for
  3419 slanted text style, and "tt" for plain type-writer; if no
  3420 \isabellestyle command is given, output is according to slanted
  3421 type-writer);
  3422 
  3423 * support sub/super scripts (for single symbols only), input syntax is
  3424 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3425 
  3426 * some more standard symbols; see Appendix A of the system manual for
  3427 the complete list of symbols defined in isabellesym.sty;
  3428 
  3429 * improved isabelle style files; more abstract symbol implementation
  3430 (should now use \isamath{...} and \isatext{...} in custom symbol
  3431 definitions);
  3432 
  3433 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3434 state; Note that presentation of goal states does not conform to
  3435 actual human-readable proof documents.  Please do not include goal
  3436 states into document output unless you really know what you are doing!
  3437 
  3438 * proper indentation of antiquoted output with proportional LaTeX
  3439 fonts;
  3440 
  3441 * no_document ML operator temporarily disables LaTeX document
  3442 generation;
  3443 
  3444 * isatool unsymbolize tunes sources for plain ASCII communication;
  3445 
  3446 
  3447 *** Isar ***
  3448 
  3449 * Pure: Isar now suffers initial goal statements to contain unbound
  3450 schematic variables (this does not conform to actual readable proof
  3451 documents, due to unpredictable outcome and non-compositional proof
  3452 checking); users who know what they are doing may use schematic goals
  3453 for Prolog-style synthesis of proven results;
  3454 
  3455 * Pure: assumption method (an implicit finishing) now handles actual
  3456 rules as well;
  3457 
  3458 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  3459 initial goal, declare "that" only as Pure intro (only for single
  3460 steps); the "that" rule assumption may now be involved in implicit
  3461 finishing, thus ".." becomes a feasible for trivial obtains;
  3462 
  3463 * Pure: default proof step now includes 'intro_classes'; thus trivial
  3464 instance proofs may be performed by "..";
  3465 
  3466 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  3467 statements as well;
  3468 
  3469 * Pure: more robust selection of calculational rules;
  3470 
  3471 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  3472 rule (as well as the assumption rule);
  3473 
  3474 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  3475 lemmas, using the graph browser tool;
  3476 
  3477 * Pure: predict failure of "show" in interactive mode;
  3478 
  3479 * Pure: 'thms_containing' now takes actual terms as arguments;
  3480 
  3481 * HOL: improved method 'induct' --- now handles non-atomic goals
  3482 (potential INCOMPATIBILITY); tuned error handling;
  3483 
  3484 * HOL: cases and induct rules now provide explicit hints about the
  3485 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  3486 any remaining facts are inserted into the goal verbatim;
  3487 
  3488 * HOL: local contexts (aka cases) may now contain term bindings as
  3489 well; the 'cases' and 'induct' methods new provide a ?case binding for
  3490 the result to be shown in each case;
  3491 
  3492 * HOL: added 'recdef_tc' command;
  3493 
  3494 * isatool convert assists in eliminating legacy ML scripts;
  3495 
  3496 
  3497 *** HOL ***
  3498 
  3499 * HOL/Library: a collection of generic theories to be used together
  3500 with main HOL; the theory loader path already includes this directory
  3501 by default; the following existing theories have been moved here:
  3502 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  3503 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  3504 
  3505 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  3506 modelling and verification task performed in Isabelle/HOL +
  3507 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  3508 
  3509 * HOL/Algebra: special summation operator SUM no longer exists, it has
  3510 been replaced by setsum; infix 'assoc' now has priority 50 (like
  3511 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  3512 'domain', this makes the theory consistent with mathematical
  3513 literature;
  3514 
  3515 * HOL basics: added overloaded operations "inverse" and "divide"
  3516 (infix "/"), syntax for generic "abs" operation, generic summation
  3517 operator \<Sum>;
  3518 
  3519 * HOL/typedef: simplified package, provide more useful rules (see also
  3520 HOL/subset.thy);
  3521 
  3522 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  3523 now expressed as a proper nested rule (old-style tactic scripts may
  3524 require atomize_strip_tac to cope with non-atomic premises);
  3525 
  3526 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  3527 to "split_conv" (old name still available for compatibility);
  3528 
  3529 * HOL: improved concrete syntax for strings (e.g. allows translation
  3530 rules with string literals);
  3531 
  3532 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  3533  and Fleuriot's mechanization of analysis, including the transcendental
  3534  functions for the reals;
  3535 
  3536 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  3537 
  3538 
  3539 *** CTT ***
  3540 
  3541 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  3542 "lam" is displayed as TWO lambda-symbols
  3543 
  3544 * CTT: theory Main now available, containing everything (that is, Bool
  3545 and Arith);
  3546 
  3547 
  3548 *** General ***
  3549 
  3550 * Pure: the Simplifier has been implemented properly as a derived rule
  3551 outside of the actual kernel (at last!); the overall performance
  3552 penalty in practical applications is about 50%, while reliability of
  3553 the Isabelle inference kernel has been greatly improved;
  3554 
  3555 * print modes "brackets" and "no_brackets" control output of nested =>
  3556 (types) and ==> (props); the default behaviour is "brackets";
  3557 
  3558 * Provers: fast_tac (and friends) now handle actual object-logic rules
  3559 as assumptions as well;
  3560 
  3561 * system: support Poly/ML 4.0;
  3562 
  3563 * system: isatool install handles KDE version 1 or 2;
  3564 
  3565 
  3566 
  3567 New in Isabelle99-1 (October 2000)
  3568 ----------------------------------
  3569 
  3570 *** Overview of INCOMPATIBILITIES ***
  3571 
  3572 * HOL: simplification of natural numbers is much changed; to partly
  3573 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  3574 issue the following ML commands:
  3575 
  3576   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  3577   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  3578 
  3579 * HOL: simplification no longer dives into case-expressions; this is
  3580 controlled by "t.weak_case_cong" for each datatype t;
  3581 
  3582 * HOL: nat_less_induct renamed to less_induct;
  3583 
  3584 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  3585 fixsome to patch .thy and .ML sources automatically;
  3586 
  3587   select_equality  -> some_equality
  3588   select_eq_Ex     -> some_eq_ex
  3589   selectI2EX       -> someI2_ex
  3590   selectI2         -> someI2
  3591   selectI          -> someI
  3592   select1_equality -> some1_equality
  3593   Eps_sym_eq       -> some_sym_eq_trivial
  3594   Eps_eq           -> some_eq_trivial
  3595 
  3596 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  3597 
  3598 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  3599 instead);
  3600 
  3601 * HOL: the recursion equations generated by 'recdef' are now called
  3602 f.simps instead of f.rules;
  3603 
  3604 * HOL: qed_spec_mp now also handles bounded ALL as well;
  3605 
  3606 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  3607 sometimes be needed;
  3608 
  3609 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  3610 
  3611 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  3612 
  3613 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  3614 product is now "<*>" instead of "Times"; the lexicographic product is
  3615 now "<*lex*>" instead of "**";
  3616 
  3617 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  3618 of main HOL, but was unused); better use HOL's datatype package;
  3619 
  3620 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  3621 the old syntax may be recovered as follows:
  3622 
  3623   syntax (symbols)
  3624     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  3625       (infixl "\\<oplus>" 100)
  3626 
  3627 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3628 
  3629 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  3630 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  3631 internally;
  3632 
  3633 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  3634 changed from A/r to A//r;
  3635 
  3636 * ZF: new treatment of arithmetic (nat & int) may break some old
  3637 proofs;
  3638 
  3639 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  3640 rulify -> rule_format, elimify -> elim_format, ...);
  3641 
  3642 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3643 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  3644 should have to change intro!! to intro? only); replaced "delrule" by
  3645 "rule del";
  3646 
  3647 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  3648 
  3649 * Provers: strengthened force_tac by using new first_best_tac;
  3650 
  3651 * LaTeX document preparation: several changes of isabelle.sty (see
  3652 lib/texinputs);
  3653 
  3654 
  3655 *** Document preparation ***
  3656 
  3657 * formal comments (text blocks etc.) in new-style theories may now
  3658 contain antiquotations of thm/prop/term/typ/text to be presented
  3659 according to latex print mode; concrete syntax is like this:
  3660 @{term[show_types] "f(x) = a + x"};
  3661 
  3662 * isatool mkdir provides easy setup of Isabelle session directories,
  3663 including proper document sources;
  3664 
  3665 * generated LaTeX sources are now deleted after successful run
  3666 (isatool document -c); may retain a copy somewhere else via -D option
  3667 of isatool usedir;
  3668 
  3669 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  3670 style files, achieving self-contained LaTeX sources and simplifying
  3671 LaTeX debugging;
  3672 
  3673 * old-style theories now produce (crude) LaTeX output as well;
  3674 
  3675 * browser info session directories are now self-contained (may be put
  3676 on WWW server seperately); improved graphs of nested sessions; removed
  3677 graph for 'all sessions';
  3678 
  3679 * several improvements in isabelle style files; \isabellestyle{it}
  3680 produces fake math mode output; \isamarkupheader is now \section by
  3681 default; see lib/texinputs/isabelle.sty etc.;
  3682 
  3683 
  3684 *** Isar ***
  3685 
  3686 * Isar/Pure: local results and corresponding term bindings are now
  3687 subject to Hindley-Milner polymorphism (similar to ML); this
  3688 accommodates incremental type-inference very nicely;
  3689 
  3690 * Isar/Pure: new derived language element 'obtain' supports
  3691 generalized existence reasoning;
  3692 
  3693 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  3694 support accumulation of results, without applying any rules yet;
  3695 useful to collect intermediate results without explicit name
  3696 references, and for use with transitivity rules with more than 2
  3697 premises;
  3698 
  3699 * Isar/Pure: scalable support for case-analysis type proofs: new
  3700 'case' language element refers to local contexts symbolically, as
  3701 produced by certain proof methods; internally, case names are attached
  3702 to theorems as "tags";
  3703 
  3704 * Isar/Pure: theory command 'hide' removes declarations from
  3705 class/type/const name spaces;
  3706 
  3707 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  3708 indicate potential overloading;
  3709 
  3710 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  3711 
  3712 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  3713 "{a,b,c}" instead of {a,b,c};
  3714 
  3715 * Isar/Pure now provides its own version of intro/elim/dest
  3716 attributes; useful for building new logics, but beware of confusion
  3717 with the version in Provers/classical;
  3718 
  3719 * Isar/Pure: the local context of (non-atomic) goals is provided via
  3720 case name 'antecedent';
  3721 
  3722 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  3723 to the current context is now done automatically);
  3724 
  3725 * Isar/Pure: theory command 'method_setup' provides a simple interface
  3726 for definining proof methods in ML;
  3727 
  3728 * Isar/Provers: intro/elim/dest attributes changed; renamed
  3729 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  3730 most cases, one should have to change intro!! to intro? only);
  3731 replaced "delrule" by "rule del";
  3732 
  3733 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  3734 'symmetric' attribute (the latter supercedes [RS sym]);
  3735 
  3736 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  3737 method modifier); 'simp' method: 'only:' modifier removes loopers as
  3738 well (including splits);
  3739 
  3740 * Isar/Provers: Simplifier and Classical methods now support all kind
  3741 of modifiers used in the past, including 'cong', 'iff', etc.
  3742 
  3743 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  3744 of Simplifier and Classical reasoner);
  3745 
  3746 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  3747 now support named cases; major packages (inductive, datatype, primrec,
  3748 recdef) support case names and properly name parameters;
  3749 
  3750 * Isar/HOL: new transitivity rules for substitution in inequalities --
  3751 monotonicity conditions are extracted to be proven at end of
  3752 calculations;
  3753 
  3754 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  3755 method anyway;
  3756 
  3757 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  3758 split_if split_if_asm; datatype package provides theorems foo.splits =
  3759 foo.split foo.split_asm for each datatype;
  3760 
  3761 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  3762 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  3763 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  3764 use "(cases (simplified))" method in proper proof texts);
  3765 
  3766 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  3767 
  3768 * Isar: names of theorems etc. may be natural numbers as well;
  3769 
  3770 * Isar: 'pr' command: optional arguments for goals_limit and
  3771 ProofContext.prems_limit; no longer prints theory contexts, but only
  3772 proof states;
  3773 
  3774 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  3775 additional print modes to be specified; e.g. "pr(latex)" will print
  3776 proof state according to the Isabelle LaTeX style;
  3777 
  3778 * Isar: improved support for emulating tactic scripts, including proof
  3779 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  3780 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  3781 (for HOL datatypes);
  3782 
  3783 * Isar: simplified (more robust) goal selection of proof methods: 1st
  3784 goal, all goals, or explicit goal specifier (tactic emulation); thus
  3785 'proof method scripts' have to be in depth-first order;
  3786 
  3787 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  3788 
  3789 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  3790 should instead use individual commands for printing items
  3791 (print_commands, print_methods etc.);
  3792 
  3793 * Isar: added 'nothing' --- the empty list of theorems;
  3794 
  3795 
  3796 *** HOL ***
  3797 
  3798 * HOL/MicroJava: formalization of a fragment of Java, together with a
  3799 corresponding virtual machine and a specification of its bytecode
  3800 verifier and a lightweight bytecode verifier, including proofs of
  3801 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  3802 Cornelia Pusch (see also the homepage of project Bali at
  3803 http://isabelle.in.tum.de/Bali/);
  3804 
  3805 * HOL/Algebra: new theory of rings and univariate polynomials, by
  3806 Clemens Ballarin;
  3807 
  3808 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  3809 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  3810 Rasmussen;
  3811 
  3812 * HOL/Lattice: fundamental concepts of lattice theory and order
  3813 structures, including duals, properties of bounds versus algebraic
  3814 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  3815 Theorem for complete lattices etc.; may also serve as a demonstration
  3816 for abstract algebraic reasoning using axiomatic type classes, and
  3817 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  3818 
  3819 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  3820 von Oheimb;
  3821 
  3822 * HOL/IMPP: extension of IMP with local variables and mutually
  3823 recursive procedures, by David von Oheimb;
  3824 
  3825 * HOL/Lambda: converted into new-style theory and document;
  3826 
  3827 * HOL/ex/Multiquote: example of multiple nested quotations and
  3828 anti-quotations -- basically a generalized version of de-Bruijn
  3829 representation; very useful in avoiding lifting of operations;
  3830 
  3831 * HOL/record: added general record equality rule to simpset; fixed
  3832 select-update simplification procedure to handle extended records as
  3833 well; admit "r" as field name;
  3834 
  3835 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  3836 other numeric types and also as the identity of groups, rings, etc.;
  3837 
  3838 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  3839 Types nat and int belong to this axclass;
  3840 
  3841 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  3842    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  3843    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  3844   two terms #m*u and #n*u are replaced by #(m+n)*u
  3845     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  3846   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  3847     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  3848 
  3849 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  3850 powerful prover for predicate logic but knows nothing of clasets; see
  3851 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  3852 
  3853 * HOL: new version of "case_tac" subsumes both boolean case split and
  3854 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  3855 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  3856 
  3857 * HOL: simplification no longer dives into case-expressions: only the
  3858 selector expression is simplified, but not the remaining arms; to
  3859 enable full simplification of case-expressions for datatype t, you may
  3860 remove t.weak_case_cong from the simpset, either globally (Delcongs
  3861 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  3862 
  3863 * HOL/recdef: the recursion equations generated by 'recdef' for
  3864 function 'f' are now called f.simps instead of f.rules; if all
  3865 termination conditions are proved automatically, these simplification
  3866 rules are added to the simpset, as in primrec; rules may be named
  3867 individually as well, resulting in a separate list of theorems for
  3868 each equation;
  3869 
  3870 * HOL/While is a new theory that provides a while-combinator. It
  3871 permits the definition of tail-recursive functions without the
  3872 provision of a termination measure. The latter is necessary once the
  3873 invariant proof rule for while is applied.
  3874 
  3875 * HOL: new (overloaded) notation for the set of elements below/above
  3876 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  3877 
  3878 * HOL: theorems impI, allI, ballI bound as "strip";
  3879 
  3880 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  3881 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  3882 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  3883 
  3884 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  3885 
  3886 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  3887 main HOL, but was unused);
  3888 
  3889 * HOL: fewer consts declared as global (e.g. have to refer to
  3890 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  3891 
  3892 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  3893 in case of overlap with user translations (e.g. judgements over
  3894 tuples); (note that the underlying logical represenation is still
  3895 bogus);
  3896 
  3897 
  3898 *** ZF ***
  3899 
  3900 * ZF: simplification automatically cancels common terms in arithmetic
  3901 expressions over nat and int;
  3902 
  3903 * ZF: new treatment of nat to minimize type-checking: all operators
  3904 coerce their operands to a natural number using the function natify,
  3905 making the algebraic laws unconditional;
  3906 
  3907 * ZF: as above, for int: operators coerce their operands to an integer
  3908 using the function intify;
  3909 
  3910 * ZF: the integer library now contains many of the usual laws for the
  3911 orderings, including $<=, and monotonicity laws for $+ and $*;
  3912 
  3913 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  3914 simplification;
  3915 
  3916 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  3917 to the simplifier and classical reasoner simultaneously;
  3918 
  3919 
  3920 *** General ***
  3921 
  3922 * Provers: blast_tac now handles actual object-logic rules as
  3923 assumptions; note that auto_tac uses blast_tac internally as well;
  3924 
  3925 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  3926 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  3927 
  3928 * Provers: delrules now handles destruct rules as well (no longer need
  3929 explicit make_elim);
  3930 
  3931 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  3932   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3933 use instead the strong form,
  3934   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  3935 in HOL, FOL and ZF the function cla_make_elim will create such rules
  3936 from destruct-rules;
  3937 
  3938 * Provers: Simplifier.easy_setup provides a fast path to basic
  3939 Simplifier setup for new object-logics;
  3940 
  3941 * Pure: AST translation rules no longer require constant head on LHS;
  3942 
  3943 * Pure: improved name spaces: ambiguous output is qualified; support
  3944 for hiding of names;
  3945 
  3946 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  3947 XSYMBOL_HOME; no longer need to do manual configuration in most
  3948 situations;
  3949 
  3950 * system: compression of ML heaps images may now be controlled via -c
  3951 option of isabelle and isatool usedir (currently only observed by
  3952 Poly/ML);
  3953 
  3954 * system: isatool installfonts may handle X-Symbol fonts as well (very
  3955 useful for remote X11);
  3956 
  3957 * system: provide TAGS file for Isabelle sources;
  3958 
  3959 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  3960 order;
  3961 
  3962 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  3963 timing flag supersedes proof_timing and Toplevel.trace;
  3964 
  3965 * ML: new combinators |>> and |>>> for incremental transformations
  3966 with secondary results (e.g. certain theory extensions):
  3967 
  3968 * ML: PureThy.add_defs gets additional argument to indicate potential
  3969 overloading (usually false);
  3970 
  3971 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  3972 results;
  3973 
  3974 
  3975 
  3976 New in Isabelle99 (October 1999)
  3977 --------------------------------
  3978 
  3979 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3980 
  3981 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  3982 are no longer simplified.  (This allows the simplifier to unfold recursive
  3983 functional programs.)  To restore the old behaviour, declare
  3984 
  3985     Delcongs [if_weak_cong];
  3986 
  3987 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  3988 complement;
  3989 
  3990 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  3991 
  3992 * HOL/datatype: mutual_induct_tac no longer exists --
  3993   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  3994 
  3995 * HOL/typedef: fixed type inference for representing set; type
  3996 arguments now have to occur explicitly on the rhs as type constraints;
  3997 
  3998 * ZF: The con_defs part of an inductive definition may no longer refer
  3999 to constants declared in the same theory;
  4000 
  4001 * HOL, ZF: the function mk_cases, generated by the inductive
  4002 definition package, has lost an argument.  To simplify its result, it
  4003 uses the default simpset instead of a supplied list of theorems.
  4004 
  4005 * HOL/List: the constructors of type list are now Nil and Cons;
  4006 
  4007 * Simplifier: the type of the infix ML functions
  4008         setSSolver addSSolver setSolver addSolver
  4009 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4010 for packaging solvers. A solver is created via
  4011         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4012 where the string argument is only a comment.
  4013 
  4014 
  4015 *** Proof tools ***
  4016 
  4017 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4018 decision procedure for linear arithmetic. Currently it is used for
  4019 types `nat', `int', and `real' in HOL (see below); it can, should and
  4020 will be instantiated for other types and logics as well.
  4021 
  4022 * The simplifier now accepts rewrite rules with flexible heads, eg
  4023      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4024   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4025   matching.
  4026 
  4027 
  4028 *** General ***
  4029 
  4030 * New Isabelle/Isar subsystem provides an alternative to traditional
  4031 tactical theorem proving; together with the ProofGeneral/isar user
  4032 interface it offers an interactive environment for developing human
  4033 readable proof documents (Isar == Intelligible semi-automated
  4034 reasoning); for further information see isatool doc isar-ref,
  4035 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4036 
  4037 * improved and simplified presentation of theories: better HTML markup
  4038 (including colors), graph views in several sizes; isatool usedir now
  4039 provides a proper interface for user theories (via -P option); actual
  4040 document preparation based on (PDF)LaTeX is available as well (for
  4041 new-style theories only); see isatool doc system for more information;
  4042 
  4043 * native support for Proof General, both for classic Isabelle and
  4044 Isabelle/Isar;
  4045 
  4046 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4047 using the graph browser tool;
  4048 
  4049 * Isabelle manuals now also available as PDF;
  4050 
  4051 * theory loader rewritten from scratch (may not be fully
  4052 bug-compatible); old loadpath variable has been replaced by show_path,
  4053 add_path, del_path, reset_path functions; new operations such as
  4054 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4055 isatool doc ref);
  4056 
  4057 * improved isatool install: option -k creates KDE application icon,
  4058 option -p DIR installs standalone binaries;
  4059 
  4060 * added ML_PLATFORM setting (useful for cross-platform installations);
  4061 more robust handling of platform specific ML images for SML/NJ;
  4062 
  4063 * the settings environment is now statically scoped, i.e. it is never
  4064 created again in sub-processes invoked from isabelle, isatool, or
  4065 Isabelle;
  4066 
  4067 * path element specification '~~' refers to '$ISABELLE_HOME';
  4068 
  4069 * in locales, the "assumes" and "defines" parts may be omitted if
  4070 empty;
  4071 
  4072 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4073 long arrows);
  4074 
  4075 * new print_mode "HTML";
  4076 
  4077 * new flag show_tags controls display of tags of theorems (which are
  4078 basically just comments that may be attached by some tools);
  4079 
  4080 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4081 mode and goal output format:
  4082 
  4083 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4084 244c244
  4085 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4086 ---
  4087 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4088 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4089 181c181
  4090 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4091 ---
  4092 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4093 
  4094 * function bind_thms stores lists of theorems (cf. bind_thm);
  4095 
  4096 * new shorthand tactics ftac, eatac, datac, fatac;
  4097 
  4098 * qed (and friends) now accept "" as result name; in that case the
  4099 theorem is not stored, but proper checks and presentation of the
  4100 result still apply;
  4101 
  4102 * theorem database now also indexes constants "Trueprop", "all",
  4103 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4104 
  4105 
  4106 *** HOL ***
  4107 
  4108 ** HOL arithmetic **
  4109 
  4110 * There are now decision procedures for linear arithmetic over nat and
  4111 int:
  4112 
  4113 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4114 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4115 are treated as atomic; subformulae not involving type `nat' or `int'
  4116 are ignored; quantified subformulae are ignored unless they are
  4117 positive universal or negative existential. The tactic has to be
  4118 invoked by hand and can be a little bit slow. In particular, the
  4119 running time is exponential in the number of occurrences of `min' and
  4120 `max', and `-' on `nat'.
  4121 
  4122 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4123 (negated) (in)equalities among the premises and the conclusion into
  4124 account (i.e. no compound formulae) and does not know about `min' and
  4125 `max', and `-' on `nat'. It is fast and is used automatically by the
  4126 simplifier.
  4127 
  4128 NB: At the moment, these decision procedures do not cope with mixed
  4129 nat/int formulae where the two parts interact, such as `m < n ==>
  4130 int(m) < int(n)'.
  4131 
  4132 * HOL/Numeral provides a generic theory of numerals (encoded
  4133 efficiently as bit strings); setup for types nat/int/real is in place;
  4134 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4135 int, existing theories and proof scripts may require a few additional
  4136 type constraints;
  4137 
  4138 * integer division and remainder can now be performed on constant
  4139 arguments;
  4140 
  4141 * many properties of integer multiplication, division and remainder
  4142 are now available;
  4143 
  4144 * An interface to the Stanford Validity Checker (SVC) is available through the
  4145 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4146 are proved automatically.  SVC must be installed separately, and its results
  4147 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4148 invocation of the underlying oracle).  For SVC see
  4149   http://verify.stanford.edu/SVC
  4150 
  4151 * IsaMakefile: the HOL-Real target now builds an actual image;
  4152 
  4153 
  4154 ** HOL misc **
  4155 
  4156 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4157 (in Isabelle/Isar) -- by Gertrud Bauer;
  4158 
  4159 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4160 analysis for assembly languages with subtypes;
  4161 
  4162 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4163 -- avoids syntactic ambiguities and treats state, transition, and
  4164 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4165 changed syntax and (many) tactics;
  4166 
  4167 * HOL/inductive: Now also handles more general introduction rules such
  4168   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4169   theorems are now maintained within the theory (maintained via the
  4170   "mono" attribute);
  4171 
  4172 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4173   (using function types) such as
  4174 
  4175   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4176 
  4177 * HOL/record: record_simproc (part of the default simpset) takes care
  4178 of selectors applied to updated records; record_split_tac is no longer
  4179 part of the default claset; update_defs may now be removed from the
  4180 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4181 
  4182   claset_ref () := claset() addSWrapper record_split_wrapper;
  4183   Delsimprocs [record_simproc]
  4184 
  4185 * HOL/typedef: fixed type inference for representing set; type
  4186 arguments now have to occur explicitly on the rhs as type constraints;
  4187 
  4188 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4189 names rather than an ML expression;
  4190 
  4191 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4192 supplied later.  Program schemes can be defined, such as
  4193     "While B C s = (if B s then While B C (C s) else s)"
  4194 where the well-founded relation can be chosen after B and C have been given.
  4195 
  4196 * HOL/List: the constructors of type list are now Nil and Cons;
  4197 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4198 course, ML tools referring to List.list.op # etc. have to be adapted;
  4199 
  4200 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4201 disabled by default; run isabelle with option -m HOL to get back to
  4202 the original Gordon/HOL-style output;
  4203 
  4204 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4205 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4206 
  4207 * HOL basic syntax simplified (more orthogonal): all variants of
  4208 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4209 Eps operator is provided as well: "SOME x. P[x]";
  4210 
  4211 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4212 
  4213 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4214 thus available for user theories;
  4215 
  4216 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4217 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4218 time;
  4219 
  4220 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4221 several times and then mp;
  4222 
  4223 
  4224 *** LK ***
  4225 
  4226 * the notation <<...>> is now available as a notation for sequences of
  4227 formulas;
  4228 
  4229 * the simplifier is now installed
  4230 
  4231 * the axiom system has been generalized (thanks to Soren Heilmann)
  4232 
  4233 * the classical reasoner now has a default rule database
  4234 
  4235 
  4236 *** ZF ***
  4237 
  4238 * new primrec section allows primitive recursive functions to be given
  4239 directly (as in HOL) over datatypes and the natural numbers;
  4240 
  4241 * new tactics induct_tac and exhaust_tac for induction (or case
  4242 analysis) over datatypes and the natural numbers;
  4243 
  4244 * the datatype declaration of type T now defines the recursor T_rec;
  4245 
  4246 * simplification automatically does freeness reasoning for datatype
  4247 constructors;
  4248 
  4249 * automatic type-inference, with AddTCs command to insert new
  4250 type-checking rules;
  4251 
  4252 * datatype introduction rules are now added as Safe Introduction rules
  4253 to the claset;
  4254 
  4255 * the syntax "if P then x else y" is now available in addition to
  4256 if(P,x,y);
  4257 
  4258 
  4259 *** Internal programming interfaces ***
  4260 
  4261 * tuned simplifier trace output; new flag debug_simp;
  4262 
  4263 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4264 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4265 
  4266 * AxClass.axclass_tac lost the theory argument;
  4267 
  4268 * tuned current_goals_markers semantics: begin / end goal avoids
  4269 printing empty lines;
  4270 
  4271 * removed prs and prs_fn hook, which was broken because it did not
  4272 include \n in its semantics, forcing writeln to add one
  4273 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4274 string -> unit if you really want to output text without newline;
  4275 
  4276 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4277 plain output, interface builders may have to enable 'isabelle_font'
  4278 mode to get Isabelle font glyphs as before;
  4279 
  4280 * refined token_translation interface; INCOMPATIBILITY: output length
  4281 now of type real instead of int;
  4282 
  4283 * theory loader actions may be traced via new ThyInfo.add_hook
  4284 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4285 your own database of information attached to *whole* theories -- as
  4286 opposed to intra-theory data slots offered via TheoryDataFun;
  4287 
  4288 * proper handling of dangling sort hypotheses (at last!);
  4289 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4290 extra sort hypotheses that can be witnessed from the type signature;
  4291 the force_strip_shyps flag is gone, any remaining shyps are simply
  4292 left in the theorem (with a warning issued by strip_shyps_warning);
  4293 
  4294 
  4295 
  4296 New in Isabelle98-1 (October 1998)
  4297 ----------------------------------
  4298 
  4299 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4300 
  4301 * several changes of automated proof tools;
  4302 
  4303 * HOL: major changes to the inductive and datatype packages, including
  4304 some minor incompatibilities of theory syntax;
  4305 
  4306 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4307 called `inj_on';
  4308 
  4309 * HOL: removed duplicate thms in Arith:
  4310   less_imp_add_less  should be replaced by  trans_less_add1
  4311   le_imp_add_le      should be replaced by  trans_le_add1
  4312 
  4313 * HOL: unary minus is now overloaded (new type constraints may be
  4314 required);
  4315 
  4316 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4317 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4318 now taken as an integer constant.
  4319 
  4320 * Pure: ML function 'theory_of' renamed to 'theory';
  4321 
  4322 
  4323 *** Proof tools ***
  4324 
  4325 * Simplifier:
  4326   1. Asm_full_simp_tac is now more aggressive.
  4327      1. It will sometimes reorient premises if that increases their power to
  4328         simplify.
  4329      2. It does no longer proceed strictly from left to right but may also
  4330         rotate premises to achieve further simplification.
  4331      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4332      old Asm_full_simp_tac in that it does not rotate premises.
  4333   2. The simplifier now knows a little bit about nat-arithmetic.
  4334 
  4335 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4336 allows for selected deletion of wrappers, by introduction of names for
  4337 wrapper functionals.  This implies that addbefore, addSbefore,
  4338 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4339 and that adding two tactics with the same name overwrites the first
  4340 one (emitting a warning).
  4341   type wrapper = (int -> tactic) -> (int -> tactic)
  4342   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4343   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4344   delWrapper, delSWrapper: claset *  string            -> claset
  4345   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4346 
  4347 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4348 semantics; addbefore now affects only the unsafe part of step_tac
  4349 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4350 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4351 by Force_tac;
  4352 
  4353 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4354 compWrapper; added safe wrapper (and access functions for it);
  4355 
  4356 * HOL/split_all_tac is now much faster and fails if there is nothing
  4357 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4358 and the names of the automatically generated variables have changed.
  4359 split_all_tac has moved within claset() from unsafe wrappers to safe
  4360 wrappers, which means that !!-bound variables are split much more
  4361 aggressively, and safe_tac and clarify_tac now split such variables.
  4362 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4363 Note: the same holds for record_split_tac, which does the job of
  4364 split_all_tac for record fields.
  4365 
  4366 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4367 permanently to the default simpset using Addsplits just like
  4368 Addsimps. They can be removed via Delsplits just like
  4369 Delsimps. Lower-case versions are also available.
  4370 
  4371 * HOL/Simplifier: The rule split_if is now part of the default
  4372 simpset. This means that the simplifier will eliminate all occurrences
  4373 of if-then-else in the conclusion of a goal. To prevent this, you can
  4374 either remove split_if completely from the default simpset by
  4375 `Delsplits [split_if]' or remove it in a specific call of the
  4376 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4377 other case splitting rules to/from the default simpset: every datatype
  4378 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4379 t is the name of the datatype).
  4380 
  4381 * Classical reasoner / Simplifier combination: new force_tac (and
  4382 derivatives Force_tac, force) combines rewriting and classical
  4383 reasoning (and whatever other tools) similarly to auto_tac, but is
  4384 aimed to solve the given subgoal completely.
  4385 
  4386 
  4387 *** General ***
  4388 
  4389 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4390 and `goalw': the theory is no longer needed as an explicit argument -
  4391 the current theory context is used; assumptions are no longer returned
  4392 at the ML-level unless one of them starts with ==> or !!; it is
  4393 recommended to convert to these new commands using isatool fixgoal
  4394 (backup your sources first!);
  4395 
  4396 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4397 the current theory context, and 'theory' to lookup stored theories;
  4398 
  4399 * new theory section 'locale' for declaring constants, assumptions and
  4400 definitions that have local scope;
  4401 
  4402 * new theory section 'nonterminals' for purely syntactic types;
  4403 
  4404 * new theory section 'setup' for generic ML setup functions
  4405 (e.g. package initialization);
  4406 
  4407 * the distribution now includes Isabelle icons: see
  4408 lib/logo/isabelle-{small,tiny}.xpm;
  4409 
  4410 * isatool install - install binaries with absolute references to
  4411 ISABELLE_HOME/bin;
  4412 
  4413 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4414 
  4415 * print mode 'emacs' reserved for Isamode;
  4416 
  4417 * support multiple print (ast) translations per constant name;
  4418 
  4419 * theorems involving oracles are now printed with a suffixed [!];
  4420 
  4421 
  4422 *** HOL ***
  4423 
  4424 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4425 
  4426 * HOL/inductive package reorganized and improved: now supports mutual
  4427 definitions such as
  4428 
  4429   inductive EVEN ODD
  4430     intrs
  4431       null "0 : EVEN"
  4432       oddI "n : EVEN ==> Suc n : ODD"
  4433       evenI "n : ODD ==> Suc n : EVEN"
  4434 
  4435 new theorem list "elims" contains an elimination rule for each of the
  4436 recursive sets; inductive definitions now handle disjunctive premises
  4437 correctly (also ZF);
  4438 
  4439 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4440 "mutual_induct" no longer exists - the induction rule is always
  4441 contained in "induct";
  4442 
  4443 
  4444 * HOL/datatype package re-implemented and greatly improved: now
  4445 supports mutually recursive datatypes such as
  4446 
  4447   datatype
  4448     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  4449             | SUM ('a aexp) ('a aexp)
  4450             | DIFF ('a aexp) ('a aexp)
  4451             | NUM 'a
  4452   and
  4453     'a bexp = LESS ('a aexp) ('a aexp)
  4454             | AND ('a bexp) ('a bexp)
  4455             | OR ('a bexp) ('a bexp)
  4456 
  4457 as well as indirectly recursive datatypes such as
  4458 
  4459   datatype
  4460     ('a, 'b) term = Var 'a
  4461                   | App 'b ((('a, 'b) term) list)
  4462 
  4463 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  4464 induction on mutually / indirectly recursive datatypes.
  4465 
  4466 Primrec equations are now stored in theory and can be accessed via
  4467 <function_name>.simps.
  4468 
  4469 INCOMPATIBILITIES:
  4470 
  4471   - Theories using datatypes must now have theory Datatype as an
  4472     ancestor.
  4473   - The specific <typename>.induct_tac no longer exists - use the
  4474     generic induct_tac instead.
  4475   - natE has been renamed to nat.exhaust - use exhaust_tac
  4476     instead of res_inst_tac ... natE. Note that the variable
  4477     names in nat.exhaust differ from the names in natE, this
  4478     may cause some "fragile" proofs to fail.
  4479   - The theorems split_<typename>_case and split_<typename>_case_asm
  4480     have been renamed to <typename>.split and <typename>.split_asm.
  4481   - Since default sorts of type variables are now handled correctly,
  4482     some datatype definitions may have to be annotated with explicit
  4483     sort constraints.
  4484   - Primrec definitions no longer require function name and type
  4485     of recursive argument.
  4486 
  4487 Consider using isatool fixdatatype to adapt your theories and proof
  4488 scripts to the new package (backup your sources first!).
  4489 
  4490 
  4491 * HOL/record package: considerably improved implementation; now
  4492 includes concrete syntax for record types, terms, updates; theorems
  4493 for surjective pairing and splitting !!-bound record variables; proof
  4494 support is as follows:
  4495 
  4496   1) standard conversions (selectors or updates applied to record
  4497 constructor terms) are part of the standard simpset;
  4498 
  4499   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  4500 made part of standard simpset and claset via addIffs;
  4501 
  4502   3) a tactic for record field splitting (record_split_tac) is part of
  4503 the standard claset (addSWrapper);
  4504 
  4505 To get a better idea about these rules you may retrieve them via
  4506 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  4507 the name of your record type.
  4508 
  4509 The split tactic 3) conceptually simplifies by the following rule:
  4510 
  4511   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  4512 
  4513 Thus any record variable that is bound by meta-all will automatically
  4514 blow up into some record constructor term, consequently the
  4515 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  4516 solve record problems automatically.
  4517 
  4518 
  4519 * reorganized the main HOL image: HOL/Integ and String loaded by
  4520 default; theory Main includes everything;
  4521 
  4522 * automatic simplification of integer sums and comparisons, using cancellation;
  4523 
  4524 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  4525 
  4526 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  4527 
  4528 * many new identities for unions, intersections, set difference, etc.;
  4529 
  4530 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  4531 called split_if, split_split, split_sum_case and split_nat_case (to go
  4532 with add/delsplits);
  4533 
  4534 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  4535 (?x::unit) = (); this is made part of the default simpset, which COULD
  4536 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  4537 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  4538 unit_abs_eta_conv is added in order to counter the effect of
  4539 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  4540 %u.f();
  4541 
  4542 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  4543 makes more sense);
  4544 
  4545 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4546   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4547   disjointness reasoning but breaking a few old proofs.
  4548 
  4549 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  4550 to 'converse' from 'inverse' (for compatibility with ZF and some
  4551 literature);
  4552 
  4553 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  4554 the well-founded relation;
  4555 
  4556 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  4557     Compl A.  The "Compl" syntax remains available as input syntax for this
  4558     release ONLY.
  4559 
  4560 * HOL/Update: new theory of function updates:
  4561     f(a:=b) == %x. if x=a then b else f x
  4562 may also be iterated as in f(a:=b,c:=d,...);
  4563 
  4564 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  4565 
  4566 * HOL/List:
  4567   - new function list_update written xs[i:=v] that updates the i-th
  4568     list position. May also be iterated as in xs[i:=a,j:=b,...].
  4569   - new function `upt' written [i..j(] which generates the list
  4570     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  4571     bound write [i..j], which is a shorthand for [i..j+1(].
  4572   - new lexicographic orderings and corresponding wellfoundedness theorems.
  4573 
  4574 * HOL/Arith:
  4575   - removed 'pred' (predecessor) function;
  4576   - generalized some theorems about n-1;
  4577   - many new laws about "div" and "mod";
  4578   - new laws about greatest common divisors (see theory ex/Primes);
  4579 
  4580 * HOL/Relation: renamed the relational operator r^-1 "converse"
  4581 instead of "inverse";
  4582 
  4583 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  4584   of the multiset ordering;
  4585 
  4586 * directory HOL/Real: a construction of the reals using Dedekind cuts
  4587   (not included by default);
  4588 
  4589 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  4590 
  4591 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  4592   programs, i.e. different program variables may have different types.
  4593 
  4594 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4595   [previously, this check worked only if the rewrite rule was unconditional]
  4596   Now rew can involve either definitions or equalities (either == or =).
  4597 
  4598 
  4599 *** ZF ***
  4600 
  4601 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  4602   only the theorems proved on ZF.ML;
  4603 
  4604 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  4605   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  4606   disjointness reasoning but breaking a few old proofs.
  4607 
  4608 * ZF/Update: new theory of function updates
  4609     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  4610   may also be iterated as in f(a:=b,c:=d,...);
  4611 
  4612 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  4613 
  4614 * calling (stac rew i) now fails if "rew" has no effect on the goal
  4615   [previously, this check worked only if the rewrite rule was unconditional]
  4616   Now rew can involve either definitions or equalities (either == or =).
  4617 
  4618 * case_tac provided for compatibility with HOL
  4619     (like the old excluded_middle_tac, but with subgoals swapped)
  4620 
  4621 
  4622 *** Internal programming interfaces ***
  4623 
  4624 * Pure: several new basic modules made available for general use, see
  4625 also src/Pure/README;
  4626 
  4627 * improved the theory data mechanism to support encapsulation (data
  4628 kind name replaced by private Object.kind, acting as authorization
  4629 key); new type-safe user interface via functor TheoryDataFun; generic
  4630 print_data function becomes basically useless;
  4631 
  4632 * removed global_names compatibility flag -- all theory declarations
  4633 are qualified by default;
  4634 
  4635 * module Pure/Syntax now offers quote / antiquote translation
  4636 functions (useful for Hoare logic etc. with implicit dependencies);
  4637 see HOL/ex/Antiquote for an example use;
  4638 
  4639 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  4640 cterm -> thm;
  4641 
  4642 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  4643 subgoal;
  4644 
  4645 * Display.print_goals function moved to Locale.print_goals;
  4646 
  4647 * standard print function for goals supports current_goals_markers
  4648 variable for marking begin of proof, end of proof, start of goal; the
  4649 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  4650 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  4651 for example;
  4652 
  4653 
  4654 
  4655 New in Isabelle98 (January 1998)
  4656 --------------------------------
  4657 
  4658 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4659 
  4660 * changed lexical syntax of terms / types: dots made part of long
  4661 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  4662 
  4663 * simpset (and claset) reference variable replaced by functions
  4664 simpset / simpset_ref;
  4665 
  4666 * no longer supports theory aliases (via merge) and non-trivial
  4667 implicit merge of thms' signatures;
  4668 
  4669 * most internal names of constants changed due to qualified names;
  4670 
  4671 * changed Pure/Sequence interface (see Pure/seq.ML);
  4672 
  4673 
  4674 *** General Changes ***
  4675 
  4676 * hierachically structured name spaces (for consts, types, axms, thms
  4677 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  4678 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  4679 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  4680 long_names for fully qualified output names; NOTE: ML programs
  4681 (special tactics, packages etc.) referring to internal names may have
  4682 to be adapted to cope with fully qualified names; in case of severe
  4683 backward campatibility problems try setting 'global_names' at compile
  4684 time to have enrything declared within a flat name space; one may also
  4685 fine tune name declarations in theories via the 'global' and 'local'
  4686 section;
  4687 
  4688 * reimplemented the implicit simpset and claset using the new anytype
  4689 data filed in signatures; references simpset:simpset ref etc. are
  4690 replaced by functions simpset:unit->simpset and
  4691 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  4692 to patch your ML files accordingly;
  4693 
  4694 * HTML output now includes theory graph data for display with Java
  4695 applet or isatool browser; data generated automatically via isatool
  4696 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  4697 
  4698 * defs may now be conditional; improved rewrite_goals_tac to handle
  4699 conditional equations;
  4700 
  4701 * defs now admits additional type arguments, using TYPE('a) syntax;
  4702 
  4703 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  4704 creates a new theory node; implicit merge of thms' signatures is
  4705 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  4706 transfer:theory->thm->thm in (rare) cases;
  4707 
  4708 * improved handling of draft signatures / theories; draft thms (and
  4709 ctyps, cterms) are automatically promoted to real ones;
  4710 
  4711 * slightly changed interfaces for oracles: admit many per theory, named
  4712 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  4713 
  4714 * print_goals: optional output of const types (set show_consts and
  4715 show_types);
  4716 
  4717 * improved output of warnings (###) and errors (***);
  4718 
  4719 * subgoal_tac displays a warning if the new subgoal has type variables;
  4720 
  4721 * removed old README and Makefiles;
  4722 
  4723 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  4724 
  4725 * removed obsolete init_pps and init_database;
  4726 
  4727 * deleted the obsolete tactical STATE, which was declared by
  4728     fun STATE tacfun st = tacfun st st;
  4729 
  4730 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  4731 (which abbreviates $HOME);
  4732 
  4733 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  4734 use isatool fixseq to adapt your ML programs (this works for fully
  4735 qualified references to the Sequence structure only!);
  4736 
  4737 * use_thy no longer requires writable current directory; it always
  4738 reloads .ML *and* .thy file, if either one is out of date;
  4739 
  4740 
  4741 *** Classical Reasoner ***
  4742 
  4743 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  4744 tactics that use classical reasoning to simplify a subgoal without
  4745 splitting it into several subgoals;
  4746 
  4747 * Safe_tac: like safe_tac but uses the default claset;
  4748 
  4749 
  4750 *** Simplifier ***
  4751 
  4752 * added simplification meta rules:
  4753     (asm_)(full_)simplify: simpset -> thm -> thm;
  4754 
  4755 * simplifier.ML no longer part of Pure -- has to be loaded by object
  4756 logics (again);
  4757 
  4758 * added prems argument to simplification procedures;
  4759 
  4760 * HOL, FOL, ZF: added infix function `addsplits':
  4761   instead of `<simpset> setloop (split_tac <thms>)'
  4762   you can simply write `<simpset> addsplits <thms>'
  4763 
  4764 
  4765 *** Syntax ***
  4766 
  4767 * TYPE('a) syntax for type reflection terms;
  4768 
  4769 * no longer handles consts with name "" -- declare as 'syntax' instead;
  4770 
  4771 * pretty printer: changed order of mixfix annotation preference (again!);
  4772 
  4773 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  4774 
  4775 
  4776 *** HOL ***
  4777 
  4778 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4779   with `addloop' of the simplifier to faciliate case splitting in premises.
  4780 
  4781 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  4782 
  4783 * HOL/Auth: new protocol proofs including some for the Internet
  4784   protocol TLS;
  4785 
  4786 * HOL/Map: new theory of `maps' a la VDM;
  4787 
  4788 * HOL/simplifier: simplification procedures nat_cancel_sums for
  4789 cancelling out common nat summands from =, <, <= (in)equalities, or
  4790 differences; simplification procedures nat_cancel_factor for
  4791 cancelling common factor from =, <, <= (in)equalities over natural
  4792 sums; nat_cancel contains both kinds of procedures, it is installed by
  4793 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  4794 
  4795 * HOL/simplifier: terms of the form
  4796   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  4797   are rewritten to
  4798   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  4799   and those of the form
  4800   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  4801   are rewritten to
  4802   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  4803 
  4804 * HOL/datatype
  4805   Each datatype `t' now comes with a theorem `split_t_case' of the form
  4806 
  4807   P(t_case f1 ... fn x) =
  4808      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  4809         ...
  4810        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  4811      )
  4812 
  4813   and a theorem `split_t_case_asm' of the form
  4814 
  4815   P(t_case f1 ... fn x) =
  4816     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  4817         ...
  4818        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  4819      )
  4820   which can be added to a simpset via `addsplits'. The existing theorems
  4821   expand_list_case and expand_option_case have been renamed to
  4822   split_list_case and split_option_case.
  4823 
  4824 * HOL/Arithmetic:
  4825   - `pred n' is automatically converted to `n-1'.
  4826     Users are strongly encouraged not to use `pred' any longer,
  4827     because it will disappear altogether at some point.
  4828   - Users are strongly encouraged to write "0 < n" rather than
  4829     "n ~= 0". Theorems and proof tools have been modified towards this
  4830     `standard'.
  4831 
  4832 * HOL/Lists:
  4833   the function "set_of_list" has been renamed "set" (and its theorems too);
  4834   the function "nth" now takes its arguments in the reverse order and
  4835   has acquired the infix notation "!" as in "xs!n".
  4836 
  4837 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  4838 
  4839 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  4840   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  4841 
  4842 * HOL/record: extensible records with schematic structural subtyping
  4843 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  4844 still lacks various theorems and concrete record syntax;
  4845 
  4846 
  4847 *** HOLCF ***
  4848 
  4849 * removed "axioms" and "generated by" sections;
  4850 
  4851 * replaced "ops" section by extended "consts" section, which is capable of
  4852   handling the continuous function space "->" directly;
  4853 
  4854 * domain package:
  4855   . proves theorems immediately and stores them in the theory,
  4856   . creates hierachical name space,
  4857   . now uses normal mixfix annotations (instead of cinfix...),
  4858   . minor changes to some names and values (for consistency),
  4859   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  4860   . separator between mutual domain defs: changed "," to "and",
  4861   . improved handling of sort constraints;  now they have to
  4862     appear on the left-hand side of the equations only;
  4863 
  4864 * fixed LAM <x,y,zs>.b syntax;
  4865 
  4866 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  4867 adm (%x. P (t x)), where P is chainfinite and t continuous;
  4868 
  4869 
  4870 *** FOL and ZF ***
  4871 
  4872 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  4873   with `addloop' of the simplifier to faciliate case splitting in premises.
  4874 
  4875 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  4876 in HOL, they strip ALL and --> from proved theorems;
  4877 
  4878 
  4879 
  4880 New in Isabelle94-8 (May 1997)
  4881 ------------------------------
  4882 
  4883 *** General Changes ***
  4884 
  4885 * new utilities to build / run / maintain Isabelle etc. (in parts
  4886 still somewhat experimental); old Makefiles etc. still functional;
  4887 
  4888 * new 'Isabelle System Manual';
  4889 
  4890 * INSTALL text, together with ./configure and ./build scripts;
  4891 
  4892 * reimplemented type inference for greater efficiency, better error
  4893 messages and clean internal interface;
  4894 
  4895 * prlim command for dealing with lots of subgoals (an easier way of
  4896 setting goals_limit);
  4897 
  4898 
  4899 *** Syntax ***
  4900 
  4901 * supports alternative (named) syntax tables (parser and pretty
  4902 printer); internal interface is provided by add_modesyntax(_i);
  4903 
  4904 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  4905 be used in conjunction with the Isabelle symbol font; uses the
  4906 "symbols" syntax table;
  4907 
  4908 * added token_translation interface (may translate name tokens in
  4909 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  4910 the current print_mode); IMPORTANT: user print translation functions
  4911 are responsible for marking newly introduced bounds
  4912 (Syntax.mark_boundT);
  4913 
  4914 * token translations for modes "xterm" and "xterm_color" that display
  4915 names in bold, underline etc. or colors (which requires a color
  4916 version of xterm);
  4917 
  4918 * infixes may now be declared with names independent of their syntax;
  4919 
  4920 * added typed_print_translation (like print_translation, but may
  4921 access type of constant);
  4922 
  4923 
  4924 *** Classical Reasoner ***
  4925 
  4926 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  4927 some limitations.  Blast_tac...
  4928   + ignores addss, addbefore, addafter; this restriction is intrinsic
  4929   + ignores elimination rules that don't have the correct format
  4930         (the conclusion MUST be a formula variable)
  4931   + ignores types, which can make HOL proofs fail
  4932   + rules must not require higher-order unification, e.g. apply_type in ZF
  4933     [message "Function Var's argument not a bound variable" relates to this]
  4934   + its proof strategy is more general but can actually be slower
  4935 
  4936 * substitution with equality assumptions no longer permutes other
  4937 assumptions;
  4938 
  4939 * minor changes in semantics of addafter (now called addaltern); renamed
  4940 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  4941 (and access functions for it);
  4942 
  4943 * improved combination of classical reasoner and simplifier:
  4944   + functions for handling clasimpsets
  4945   + improvement of addss: now the simplifier is called _after_ the
  4946     safe steps.
  4947   + safe variant of addss called addSss: uses safe simplifications
  4948     _during_ the safe steps. It is more complete as it allows multiple
  4949     instantiations of unknowns (e.g. with slow_tac).
  4950 
  4951 *** Simplifier ***
  4952 
  4953 * added interface for simplification procedures (functions that
  4954 produce *proven* rewrite rules on the fly, depending on current
  4955 redex);
  4956 
  4957 * ordering on terms as parameter (used for ordered rewriting);
  4958 
  4959 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  4960 
  4961 * the solver is now split into a safe and an unsafe part.
  4962 This should be invisible for the normal user, except that the
  4963 functions setsolver and addsolver have been renamed to setSolver and
  4964 addSolver; added safe_asm_full_simp_tac;
  4965 
  4966 
  4967 *** HOL ***
  4968 
  4969 * a generic induction tactic `induct_tac' which works for all datatypes and
  4970 also for type `nat';
  4971 
  4972 * a generic case distinction tactic `exhaust_tac' which works for all
  4973 datatypes and also for type `nat';
  4974 
  4975 * each datatype comes with a function `size';
  4976 
  4977 * patterns in case expressions allow tuple patterns as arguments to
  4978 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  4979 
  4980 * primrec now also works with type nat;
  4981 
  4982 * recdef: a new declaration form, allows general recursive functions to be
  4983 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  4984 
  4985 * the constant for negation has been renamed from "not" to "Not" to
  4986 harmonize with FOL, ZF, LK, etc.;
  4987 
  4988 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  4989 infinite lists;
  4990 
  4991 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  4992 
  4993 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  4994 problems in commutative rings, using axiomatic type classes for + and *;
  4995 
  4996 * more examples in HOL/MiniML and HOL/Auth;
  4997 
  4998 * more default rewrite rules for quantifiers, union/intersection;
  4999 
  5000 * a new constant `arbitrary == @x.False';
  5001 
  5002 * HOLCF/IOA replaces old HOL/IOA;
  5003 
  5004 * HOLCF changes: derived all rules and arities
  5005   + axiomatic type classes instead of classes
  5006   + typedef instead of faking type definitions
  5007   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5008   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5009   + eliminated the types void, one, tr
  5010   + use unit lift and bool lift (with translations) instead of one and tr
  5011   + eliminated blift from Lift3.thy (use Def instead of blift)
  5012   all eliminated rules are derived as theorems --> no visible changes ;
  5013 
  5014 
  5015 *** ZF ***
  5016 
  5017 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5018 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5019 as ZF_cs addSIs [equalityI];
  5020 
  5021 
  5022 
  5023 New in Isabelle94-7 (November 96)
  5024 ---------------------------------
  5025 
  5026 * allowing negative levels (as offsets) in prlev and choplev;
  5027 
  5028 * super-linear speedup for large simplifications;
  5029 
  5030 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5031 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5032 FAIL); can suppress it using the command Delsimps (ex_simps @
  5033 all_simps); De Morgan laws are also now included, by default;
  5034 
  5035 * improved printing of ==>  :  ~:
  5036 
  5037 * new object-logic "Sequents" adds linear logic, while replacing LK
  5038 and Modal (thanks to Sara Kalvala);
  5039 
  5040 * HOL/Auth: correctness proofs for authentication protocols;
  5041 
  5042 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5043 examples on HOL/Auth);
  5044 
  5045 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5046 the rewriter and classical reasoner simultaneously;
  5047 
  5048 * function uresult no longer returns theorems in "standard" format;
  5049 regain previous version by: val uresult = standard o uresult;
  5050 
  5051 
  5052 
  5053 New in Isabelle94-6
  5054 -------------------
  5055 
  5056 * oracles -- these establish an interface between Isabelle and trusted
  5057 external reasoners, which may deliver results as theorems;
  5058 
  5059 * proof objects (in particular record all uses of oracles);
  5060 
  5061 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5062 
  5063 * "constdefs" section in theory files;
  5064 
  5065 * "primrec" section (HOL) no longer requires names;
  5066 
  5067 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5068 
  5069 
  5070 
  5071 New in Isabelle94-5
  5072 -------------------
  5073 
  5074 * reduced space requirements;
  5075 
  5076 * automatic HTML generation from theories;
  5077 
  5078 * theory files no longer require "..." (quotes) around most types;
  5079 
  5080 * new examples, including two proofs of the Church-Rosser theorem;
  5081 
  5082 * non-curried (1994) version of HOL is no longer distributed;
  5083 
  5084 
  5085 
  5086 New in Isabelle94-4
  5087 -------------------
  5088 
  5089 * greatly reduced space requirements;
  5090 
  5091 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5092 
  5093 * searchable theorem database (see the section "Retrieving theorems" on
  5094 page 8 of the Reference Manual);
  5095 
  5096 * new examples, including Grabczewski's monumental case study of the
  5097 Axiom of Choice;
  5098 
  5099 * The previous version of HOL renamed to Old_HOL;
  5100 
  5101 * The new version of HOL (previously called CHOL) uses a curried syntax
  5102 for functions.  Application looks like f a b instead of f(a,b);
  5103 
  5104 * Mutually recursive inductive definitions finally work in HOL;
  5105 
  5106 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5107 translates to the operator "split";
  5108 
  5109 
  5110 
  5111 New in Isabelle94-3
  5112 -------------------
  5113 
  5114 * new infix operator, addss, allowing the classical reasoner to
  5115 perform simplification at each step of its search.  Example:
  5116         fast_tac (cs addss ss)
  5117 
  5118 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5119 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5120 look like (a,b) instead of <a,b>;
  5121 
  5122 * PLEASE NOTE: CHOL will eventually replace HOL!
  5123 
  5124 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5125 It translates to the operator "split".  A new theory of integers is available;
  5126 
  5127 * In ZF, integer numerals now denote two's-complement binary integers.
  5128 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5129 
  5130 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5131 of the Axiom of Choice;
  5132 
  5133 
  5134 
  5135 New in Isabelle94-2
  5136 -------------------
  5137 
  5138 * Significantly faster resolution;
  5139 
  5140 * the different sections in a .thy file can now be mixed and repeated
  5141 freely;
  5142 
  5143 * Database of theorems for FOL, HOL and ZF.  New
  5144 commands including qed, qed_goal and bind_thm store theorems in the database.
  5145 
  5146 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5147 a given theory (thms_of), or find out what theory a theorem was proved in
  5148 (theory_of_thm);
  5149 
  5150 * Bugs fixed in the inductive definition and datatype packages;
  5151 
  5152 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5153 and HOL_dup_cs obsolete;
  5154 
  5155 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5156 have been removed;
  5157 
  5158 * Simpler definition of function space in ZF;
  5159 
  5160 * new results about cardinal and ordinal arithmetic in ZF;
  5161 
  5162 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5163 types;
  5164 
  5165 :mode=text:wrap=hard:maxLineLen=72:
  5166 $Id$