NEWS
author wenzelm
Thu Jan 19 21:22:08 2006 +0100 (2006-01-19 ago)
changeset 18708 4b3dadb4fe33
parent 18696 60ca2c749782
child 18722 0888eca0f1be
permissions -rw-r--r--
setup: theory -> theory;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory syntax: the header format ``theory A = B + C:'' has been
    10 discontinued in favour of ``theory A imports B C begin''.  Use isatool
    11 fixheaders to convert existing theory files.  INCOMPATIBILITY.
    12 
    13 * Theory syntax: the old non-Isar theory file format has been
    14 discontinued altogether.  Note that ML proof scripts may still be used
    15 with Isar theories; migration is usually quite simple with the ML
    16 function use_legacy_bindings.  INCOMPATIBILITY.
    17 
    18 * Legacy goal package: reduced interface to the bare minimum required
    19 to keep existing proof scripts running.  Most other user-level
    20 functions are now part of the OldGoals structure, which is *not* open
    21 by default (consider isatool expandshort before open OldGoals).
    22 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
    23 these tend to cause confusion about the actual goal (!) context being
    24 used here, which is not necessarily the same as the_context().
    25 
    26 * Command 'find_theorems': support "*" wildcard in "name:" criterion.
    27 
    28 
    29 *** Document preparation ***
    30 
    31 * Added antiquotations @{ML_type text} and @{ML_struct text} which
    32 check the given source text as ML type/structure, printing verbatim.
    33 
    34 
    35 *** Pure ***
    36 
    37 * Isar: improper proof element 'guess' is like 'obtain', but derives
    38 the obtained context from the course of reasoning!  For example:
    39 
    40   assume "EX x y. A x & B y"   -- "any previous fact"
    41   then guess x and y by clarify
    42 
    43 This technique is potentially adventurous, depending on the facts and
    44 proof tools being involved here.
    45 
    46 * Isar: known facts from the proof context may be specified as literal
    47 propositions, using ASCII back-quote syntax.  This works wherever
    48 named facts used to be allowed so far, in proof commands, proof
    49 methods, attributes etc.  Literal facts are retrieved from the context
    50 according to unification of type and term parameters.  For example,
    51 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
    52 theorems in the current context, then these are valid literal facts:
    53 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
    54 
    55 There is also a proof method "fact" which does the same composition
    56 for explicit goal states, e.g. the following proof texts coincide with
    57 certain special cases of literal facts:
    58 
    59   have "A" by fact                 ==  note `A`
    60   have "A ==> B" by fact           ==  note `A ==> B`
    61   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
    62   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
    63 
    64 * Isar: 'def' now admits simultaneous definitions, e.g.:
    65 
    66   def x == "t" and y == "u"
    67 
    68 * Isar: added command 'unfolding', which is structurally similar to
    69 'using', but affects both the goal state and facts by unfolding given
    70 meta-level equations.  Thus many occurrences of the 'unfold' method or
    71 'unfolded' attribute may be replaced by first-class proof text.
    72 
    73 * Provers/induct: improved internal context management to support
    74 local fixes and defines on-the-fly.  Thus explicit meta-level
    75 connectives !! and ==> are rarely required anymore in inductive goals
    76 (using object-logic connectives for this purpose has been long
    77 obsolete anyway).  The subsequent proof patterns illustrate advanced
    78 techniques of natural induction; general datatypes and inductive sets
    79 work analogously (see also src/HOL/Lambda for realistic examples).
    80 
    81 (1) This is how to ``strengthen'' an inductive goal wrt. certain
    82 parameters:
    83 
    84   lemma
    85     fixes n :: nat and x :: 'a
    86     assumes a: "A n x"
    87     shows "P n x"
    88     using a                     -- {* make induct insert fact a *}
    89   proof (induct n fixing: x)    -- {* generalize goal to "!!x. A n x ==> P n x" *}
    90     case 0
    91     show ?case sorry
    92   next
    93     case (Suc n)
    94     note `!!x. A n x ==> P n x` -- {* induction hypothesis, according to induction rule *}
    95     note `A (Suc n) x`          -- {* induction premise, stemming from fact a *}
    96     show ?case sorry
    97   qed
    98 
    99 (2) This is how to perform induction over ``expressions of a certain
   100 form'', using a locally defined inductive parameter n == "a x"
   101 together with strengthening (the latter is usually required to get
   102 sufficiently flexible induction hypotheses):
   103 
   104   lemma
   105     fixes a :: "'a => nat"
   106     assumes a: "A (a x)"
   107     shows "P (a x)"
   108     using a
   109   proof (induct n == "a x" fixing: x)
   110     ...
   111 
   112 See also HOL/Isar_examples/Puzzle.thy for an application of the this
   113 particular technique.
   114 
   115 (3) This is how to perform existential reasoning ('obtain') by
   116 induction, while avoiding explicit object-logic encodings:
   117 
   118   fix n :: nat
   119   obtain x :: 'a where "P n x" and "Q n x"
   120   proof (induct n fixing: thesis)
   121     case 0
   122     obtain x where "P 0 x" and "Q 0 x" sorry
   123     then show thesis by (rule 0)
   124   next
   125     case (Suc n)
   126     obtain x where "P n x" and "Q n x" by (rule Suc.hyps)
   127     obtain x where "P (Suc n) x" and "Q (Suc n) x" sorry
   128     then show thesis by (rule Suc.prems)
   129   qed
   130 
   131 Here the 'fixing: thesis' specification essentially modifies the scope
   132 of the formal thesis parameter, in order to the get the whole
   133 existence statement through the induction as expected.
   134 
   135 * Provers/induct: mutual induction rules are now specified as a list
   136 of rule sharing the same induction cases.  HOL packages usually
   137 provide foo_bar.inducts for mutually defined items foo and bar
   138 (e.g. inductive sets or datatypes).  INCOMPATIBILITY, users need to
   139 specify mutual induction rules differently, i.e. like this:
   140 
   141   (induct rule: foo_bar.inducts)
   142   (induct set: foo bar)
   143   (induct type: foo bar)
   144 
   145 The ML function ProjectRule.projections turns old-style rules into the
   146 new format.
   147 
   148 * Provers/induct: improved handling of simultaneous goals.  Instead of
   149 introducing object-level conjunction, the statement is now split into
   150 several conclusions, while the corresponding symbolic cases are
   151 nested accordingly.  INCOMPATIBILITY, proofs need to be structured
   152 explicitly.  For example:
   153 
   154   lemma
   155     fixes n :: nat
   156     shows "P n" and "Q n"
   157   proof (induct n)
   158     case 0 case 1
   159     show "P 0" sorry
   160   next
   161     case 0 case 2
   162     show "Q 0" sorry
   163   next
   164     case (Suc n) case 1
   165     note `P n` and `Q n`
   166     show "P (Suc n)" sorry
   167   next
   168     case (Suc n) case 2
   169     note `P n` and `Q n`
   170     show "Q (Suc n)" sorry
   171   qed
   172 
   173 The split into subcases may be deferred as follows -- this is
   174 particularly relevant for goal statements with local premises.
   175 
   176   lemma
   177     fixes n :: nat
   178     shows "A n ==> P n" and "B n ==> Q n"
   179   proof (induct n)
   180     case 0
   181     {
   182       case 1
   183       note `A 0`
   184       show "P 0" sorry
   185     next
   186       case 2
   187       note `B 0`
   188       show "Q 0" sorry
   189     }
   190   next
   191     case (Suc n)
   192     note `A n ==> P n` and `B n ==> Q n`
   193     {
   194       case 1
   195       note `A (Suc n)`
   196       show "P (Suc n)" sorry
   197     next
   198       case 2
   199       note `B (Suc n)`
   200       show "Q (Suc n)" sorry
   201     }
   202   qed
   203 
   204 If simultaneous goals are to be used with mutual rules, the statement
   205 needs to be structured carefully as a two-level conjunction, using
   206 lists of propositions separated by 'and':
   207 
   208   lemma
   209     shows "a : A ==> P1 a"
   210           "a : A ==> P2 a"
   211       and "b : B ==> Q1 b"
   212           "b : B ==> Q2 b"
   213           "b : B ==> Q3 b"
   214   proof (induct set: A B)
   215 
   216 * Provers/induct: support coinduction as well.  See
   217 src/HOL/Library/Coinductive_List.thy for various examples.
   218 
   219 * Simplifier: by default the simplifier trace only shows top level rewrites
   220 now. That is, trace_simp_depth_limit is set to 1 by default. Thus there is
   221 less danger of being flooded by the trace. The trace indicates where parts
   222 have been suppressed.
   223   
   224 * Provers/classical: removed obsolete classical version of elim_format
   225 attribute; classical elim/dest rules are now treated uniformly when
   226 manipulating the claset.
   227 
   228 * Provers/classical: stricter checks to ensure that supplied intro,
   229 dest and elim rules are well-formed; dest and elim rules must have at
   230 least one premise.
   231 
   232 * Provers/classical: attributes dest/elim/intro take an optional
   233 weight argument for the rule (just as the Pure versions).  Weights are
   234 ignored by automated tools, but determine the search order of single
   235 rule steps.
   236 
   237 * Syntax: input syntax now supports dummy variable binding "%_. b",
   238 where the body does not mention the bound variable.  Note that dummy
   239 patterns implicitly depend on their context of bounds, which makes
   240 "{_. _}" match any set comprehension as expected.  Potential
   241 INCOMPATIBILITY -- parse translations need to cope with syntactic
   242 constant "_idtdummy" in the binding position.
   243 
   244 * Syntax: removed obsolete syntactic constant "_K" and its associated
   245 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   246 for example "A -> B" => "Pi A (%_. B)".
   247 
   248 
   249 *** HOL ***
   250 
   251 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
   252 'rule' method.
   253 
   254 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   255 25 like -->); output depends on the "iff" print_mode, the default is
   256 "A = B" (with priority 50).
   257 
   258 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
   259 
   260 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   261 "t = s" to False (by simproc "neq_simproc").  For backward
   262 compatibility this can be disabled by ML "reset use_neq_simproc".
   263 
   264 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   265 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   266 "=" on type bool) are handled, variable names of the form "lit_<n>"
   267 are no longer reserved, significant speedup.
   268 
   269 * inductive and datatype: provide projections of mutual rules, bundled
   270 as foo_bar.inducts;
   271 
   272 * Library: added theory Coinductive_List of potentially infinite lists
   273 as greatest fixed-point.
   274 
   275 
   276 *** ML ***
   277 
   278 * Pure/library:
   279 
   280   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   281   val fold_burrow: ('a list -> 'c -> 'b list * 'd) -> 'a list list -> 'c -> 'b list list * 'd
   282 
   283 The semantics of "burrow" is: "take a function with *simulatanously*
   284 transforms a list of value, and apply it *simulatanously* to a list of
   285 list of values of the appropriate type". Confer this with "map" which
   286 would *not* apply its argument function simulatanously but in
   287 sequence. "fold_burrow" has an additional context.
   288 
   289 Both actually avoid the usage of "unflat" since they hide away
   290 "unflat" from the user.
   291 
   292 * Pure/library: functions map2 and fold2 with curried syntax for
   293 simultanous mapping and folding:
   294 
   295     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   296     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   297 
   298 * Pure/library: indexed lists - some functions in the Isabelle library
   299 treating lists over 'a as finite mappings from [0...n] to 'a have been
   300 given more convenient names and signatures reminiscent of similar
   301 functions for alists, tables, etc:
   302 
   303   val nth: 'a list -> int -> 'a 
   304   val nth_update: int * 'a -> 'a list -> 'a list
   305   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   306   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   307 
   308 Note that fold_index starts counting at index 0, not 1 like foldln
   309 used to.
   310 
   311 * Pure/General: name_mangler.ML provides a functor for generic name
   312 mangling (bijective mapping from any expression values to strings).
   313 
   314 * Pure/General: rat.ML implements rational numbers.
   315 
   316 * Pure: datatype Context.generic joins theory/Proof.context and
   317 provides some facilities for code that works in either kind of
   318 context, notably GenericDataFun for uniform theory and proof data.
   319 
   320 * Pure: type Context.generic attribute is now the preferred
   321 representation for global vs. local attributes while avoiding code
   322 duplication; Attrib.theory/context/generic converts between different
   323 types of attributes.  Various Pure/HOL/ZF packages work with generic
   324 attributes now, INCOMPATIBILITY.
   325 
   326 * Pure: several functions of signature "... -> theory -> theory * ..."
   327 have been reoriented to "... -> theory -> ... * theory" in order to
   328 allow natural usage in combination with the ||>, ||>>, |-> and
   329 fold_map combinators.
   330 
   331 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   332 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   333 achieve the old behaviour.
   334 
   335 * Pure: the "Goal" constant is now called "prop", supporting a
   336 slightly more general idea of ``protecting'' meta-level rule
   337 statements.
   338 
   339 * Pure: structure Goal provides simple interfaces for
   340 init/conclude/finish and tactical prove operations (replacing former
   341 Tactic.prove).  Note that OldGoals.prove_goalw_cterm has long been
   342 obsolete, it is ill-behaved in a local proof context (e.g. with local
   343 fixes/assumes or in a locale context).
   344 
   345 * ML/Isar: simplified treatment of user-level errors, using exception
   346 ERROR of string uniformly.  Function error now merely raises ERROR,
   347 without any side effect on output channels.  The Isar toplevel takes
   348 care of proper display of ERROR exceptions.  ML code may use plain
   349 handle/can/try; cat_error may be used to concatenate errors like this:
   350 
   351   ... handle ERROR msg => cat_error msg "..."
   352 
   353 Toplevel ML code (run directly or through the Isar toplevel) may be
   354 embedded into the Isar toplevel with exception display/debug like
   355 this:
   356 
   357   Isar.toplevel (fn () => ...)
   358 
   359 INCOMPATIBILITY, removed special transform_error facilities, removed
   360 obsolete variants of user-level exceptions (ERROR_MESSAGE,
   361 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
   362 -- use plain ERROR instead.
   363 
   364 * Pure/Isar: Toplevel.theory_to_proof admits transactions that modify
   365 the theory before entering a proof state.  Transactions now always see
   366 a quasi-functional intermediate checkpoint, both in interactive and
   367 batch mode.
   368 
   369 * Simplifier: the simpset of a running simplification process now
   370 contains a proof context (cf. Simplifier.the_context), which is the
   371 very context that the initial simpset has been retrieved from (by
   372 simpset_of/local_simpset_of).  Consequently, all plug-in components
   373 (solver, looper etc.) may depend on arbitrary proof data.
   374 
   375 * Simplifier.inherit_context inherits the proof context (plus the
   376 local bounds) of the current simplification process; any simproc
   377 etc. that calls the Simplifier recursively should do this!  Removed
   378 former Simplifier.inherit_bounds, which is already included here --
   379 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   380 specify an explicit context using Simplifier.context/theory_context.
   381 
   382 * Simplifier/Classical Reasoner: more abstract interfaces
   383 change_simpset/claset for modifying the simpset/claset reference of a
   384 theory; raw versions simpset/claset_ref etc. have been discontinued --
   385 INCOMPATIBILITY.
   386 
   387 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   388 "Trueprop" etc.
   389 
   390 
   391 
   392 New in Isabelle2005 (October 2005)
   393 ----------------------------------
   394 
   395 *** General ***
   396 
   397 * Theory headers: the new header syntax for Isar theories is
   398 
   399   theory <name>
   400   imports <theory1> ... <theoryN>
   401   uses <file1> ... <fileM>
   402   begin
   403 
   404 where the 'uses' part is optional.  The previous syntax
   405 
   406   theory <name> = <theory1> + ... + <theoryN>:
   407 
   408 will disappear in the next release.  Use isatool fixheaders to convert
   409 existing theory files.  Note that there is no change in ancient
   410 non-Isar theories now, but these will disappear soon.
   411 
   412 * Theory loader: parent theories can now also be referred to via
   413 relative and absolute paths.
   414 
   415 * Command 'find_theorems' searches for a list of criteria instead of a
   416 list of constants. Known criteria are: intro, elim, dest, name:string,
   417 simp:term, and any term. Criteria can be preceded by '-' to select
   418 theorems that do not match. Intro, elim, dest select theorems that
   419 match the current goal, name:s selects theorems whose fully qualified
   420 name contain s, and simp:term selects all simplification rules whose
   421 lhs match term.  Any other term is interpreted as pattern and selects
   422 all theorems matching the pattern. Available in ProofGeneral under
   423 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   424 
   425   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   426 
   427 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   428 matching the current goal as introduction rule and not having "HOL."
   429 in their name (i.e. not being defined in theory HOL).
   430 
   431 * Command 'thms_containing' has been discontinued in favour of
   432 'find_theorems'; INCOMPATIBILITY.
   433 
   434 * Communication with Proof General is now 8bit clean, which means that
   435 Unicode text in UTF-8 encoding may be used within theory texts (both
   436 formal and informal parts).  Cf. option -U of the Isabelle Proof
   437 General interface.  Here are some simple examples (cf. src/HOL/ex):
   438 
   439   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   440   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   441 
   442 * Improved efficiency of the Simplifier and, to a lesser degree, the
   443 Classical Reasoner.  Typical big applications run around 2 times
   444 faster.
   445 
   446 
   447 *** Document preparation ***
   448 
   449 * Commands 'display_drafts' and 'print_drafts' perform simple output
   450 of raw sources.  Only those symbols that do not require additional
   451 LaTeX packages (depending on comments in isabellesym.sty) are
   452 displayed properly, everything else is left verbatim.  isatool display
   453 and isatool print are used as front ends (these are subject to the
   454 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   455 
   456 * Command tags control specific markup of certain regions of text,
   457 notably folding and hiding.  Predefined tags include "theory" (for
   458 theory begin and end), "proof" for proof commands, and "ML" for
   459 commands involving ML code; the additional tags "visible" and
   460 "invisible" are unused by default.  Users may give explicit tag
   461 specifications in the text, e.g. ''by %invisible (auto)''.  The
   462 interpretation of tags is determined by the LaTeX job during document
   463 preparation: see option -V of isatool usedir, or options -n and -t of
   464 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   465 \isadroptag.
   466 
   467 Several document versions may be produced at the same time via isatool
   468 usedir (the generated index.html will link all of them).  Typical
   469 specifications include ''-V document=theory,proof,ML'' to present
   470 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   471 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   472 these parts without any formal replacement text.  The Isabelle site
   473 default settings produce ''document'' and ''outline'' versions as
   474 specified above.
   475 
   476 * Several new antiquotations:
   477 
   478   @{term_type term} prints a term with its type annotated;
   479 
   480   @{typeof term} prints the type of a term;
   481 
   482   @{const const} is the same as @{term const}, but checks that the
   483   argument is a known logical constant;
   484 
   485   @{term_style style term} and @{thm_style style thm} print a term or
   486   theorem applying a "style" to it
   487 
   488   @{ML text}
   489 
   490 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   491 definitions, equations, inequations etc., 'concl' printing only the
   492 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   493 to print the specified premise.  TermStyle.add_style provides an ML
   494 interface for introducing further styles.  See also the "LaTeX Sugar"
   495 document practical applications.  The ML antiquotation prints
   496 type-checked ML expressions verbatim.
   497 
   498 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   499 and 'text' support optional locale specification '(in loc)', which
   500 specifies the default context for interpreting antiquotations.  For
   501 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   502 
   503 * Option 'locale=NAME' of antiquotations specifies an alternative
   504 context interpreting the subsequent argument.  For example: @{thm
   505 [locale=lattice] inf_assoc}.
   506 
   507 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   508 a proof context.
   509 
   510 * Proper output of antiquotations for theory commands involving a
   511 proof context (such as 'locale' or 'theorem (in loc) ...').
   512 
   513 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   514 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   515 
   516 * isatool usedir: new option -C (default true) controls whether option
   517 -D should include a copy of the original document directory; -C false
   518 prevents unwanted effects such as copying of administrative CVS data.
   519 
   520 
   521 *** Pure ***
   522 
   523 * Considerably improved version of 'constdefs' command.  Now performs
   524 automatic type-inference of declared constants; additional support for
   525 local structure declarations (cf. locales and HOL records), see also
   526 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   527 sequential dependencies of definitions within a single 'constdefs'
   528 section; moreover, the declared name needs to be an identifier.  If
   529 all fails, consider to fall back on 'consts' and 'defs' separately.
   530 
   531 * Improved indexed syntax and implicit structures.  First of all,
   532 indexed syntax provides a notational device for subscripted
   533 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   534 expressions.  Secondly, in a local context with structure
   535 declarations, number indexes \<^sub>n or the empty index (default
   536 number 1) refer to a certain fixed variable implicitly; option
   537 show_structs controls printing of implicit structures.  Typical
   538 applications of these concepts involve record types and locales.
   539 
   540 * New command 'no_syntax' removes grammar declarations (and
   541 translations) resulting from the given syntax specification, which is
   542 interpreted in the same manner as for the 'syntax' command.
   543 
   544 * 'Advanced' translation functions (parse_translation etc.) may depend
   545 on the signature of the theory context being presently used for
   546 parsing/printing, see also isar-ref manual.
   547 
   548 * Improved 'oracle' command provides a type-safe interface to turn an
   549 ML expression of type theory -> T -> term into a primitive rule of
   550 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   551 is already included here); see also FOL/ex/IffExample.thy;
   552 INCOMPATIBILITY.
   553 
   554 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   555 before); "cI" is no longer bound, use "c.intro" instead.
   556 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   557 axclasses vs. locales.
   558 
   559 * Improved internal renaming of symbolic identifiers -- attach primes
   560 instead of base 26 numbers.
   561 
   562 * New flag show_question_marks controls printing of leading question
   563 marks in schematic variable names.
   564 
   565 * In schematic variable names, *any* symbol following \<^isub> or
   566 \<^isup> is now treated as part of the base name.  For example, the
   567 following works without printing of awkward ".0" indexes:
   568 
   569   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   570     by simp
   571 
   572 * Inner syntax includes (*(*nested*) comments*).
   573 
   574 * Pretty printer now supports unbreakable blocks, specified in mixfix
   575 annotations as "(00...)".
   576 
   577 * Clear separation of logical types and nonterminals, where the latter
   578 may only occur in 'syntax' specifications or type abbreviations.
   579 Before that distinction was only partially implemented via type class
   580 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   581 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   582 exotic syntax specifications may require further adaption
   583 (e.g. Cube/Cube.thy).
   584 
   585 * Removed obsolete type class "logic", use the top sort {} instead.
   586 Note that non-logical types should be declared as 'nonterminals'
   587 rather than 'types'.  INCOMPATIBILITY for new object-logic
   588 specifications.
   589 
   590 * Attributes 'induct' and 'cases': type or set names may now be
   591 locally fixed variables as well.
   592 
   593 * Simplifier: can now control the depth to which conditional rewriting
   594 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   595 Limit.
   596 
   597 * Simplifier: simplification procedures may now take the current
   598 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   599 interface), which is very useful for calling the Simplifier
   600 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   601 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   602 low-level mk_simproc no longer applies Logic.varify internally, to
   603 allow for use in a context of fixed variables.
   604 
   605 * thin_tac now works even if the assumption being deleted contains !!
   606 or ==>.  More generally, erule now works even if the major premise of
   607 the elimination rule contains !! or ==>.
   608 
   609 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   610 
   611 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   612 from Pure, which contains all common declarations already.  Both
   613 theories are defined via plain Isabelle/Isar .thy files.
   614 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   615 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   616 use isatool fixcpure to adapt your theory and ML sources.
   617 
   618 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   619 selections of theorems in named facts via index ranges.
   620 
   621 * 'print_theorems': in theory mode, really print the difference
   622 wrt. the last state (works for interactive theory development only),
   623 in proof mode print all local facts (cf. 'print_facts');
   624 
   625 * 'hide': option '(open)' hides only base names.
   626 
   627 * More efficient treatment of intermediate checkpoints in interactive
   628 theory development.
   629 
   630 * Code generator is now invoked via code_module (incremental code
   631 generation) and code_library (modular code generation, ML structures
   632 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
   633 must be quoted when used as identifiers.
   634 
   635 * New 'value' command for reading, evaluating and printing terms using
   636 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
   637 quoted when used as identifier.
   638 
   639 
   640 *** Locales ***
   641 
   642 * New commands for the interpretation of locale expressions in
   643 theories (1), locales (2) and proof contexts (3).  These generate
   644 proof obligations from the expression specification.  After the
   645 obligations have been discharged, theorems of the expression are added
   646 to the theory, target locale or proof context.  The synopsis of the
   647 commands is a follows:
   648 
   649   (1) interpretation expr inst
   650   (2) interpretation target < expr
   651   (3) interpret expr inst
   652 
   653 Interpretation in theories and proof contexts require a parameter
   654 instantiation of terms from the current context.  This is applied to
   655 specifications and theorems of the interpreted expression.
   656 Interpretation in locales only permits parameter renaming through the
   657 locale expression.  Interpretation is smart in that interpretations
   658 that are active already do not occur in proof obligations, neither are
   659 instantiated theorems stored in duplicate.  Use 'print_interps' to
   660 inspect active interpretations of a particular locale.  For details,
   661 see the Isar Reference manual.  Examples can be found in
   662 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   663 
   664 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   665 'interpret' instead.
   666 
   667 * New context element 'constrains' for adding type constraints to
   668 parameters.
   669 
   670 * Context expressions: renaming of parameters with syntax
   671 redeclaration.
   672 
   673 * Locale declaration: 'includes' disallowed.
   674 
   675 * Proper static binding of attribute syntax -- i.e. types / terms /
   676 facts mentioned as arguments are always those of the locale definition
   677 context, independently of the context of later invocations.  Moreover,
   678 locale operations (renaming and type / term instantiation) are applied
   679 to attribute arguments as expected.
   680 
   681 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   682 actual attributes; rare situations may require Attrib.attribute to
   683 embed those attributes into Attrib.src that lack concrete syntax.
   684 Attribute implementations need to cooperate properly with the static
   685 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   686 Attrib.XXX_thm etc. already do the right thing without further
   687 intervention.  Only unusual applications -- such as "where" or "of"
   688 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   689 on the context and the facts involved -- may have to assign parsed
   690 values to argument tokens explicitly.
   691 
   692 * Changed parameter management in theorem generation for long goal
   693 statements with 'includes'.  INCOMPATIBILITY: produces a different
   694 theorem statement in rare situations.
   695 
   696 * Locale inspection command 'print_locale' omits notes elements.  Use
   697 'print_locale!' to have them included in the output.
   698 
   699 
   700 *** Provers ***
   701 
   702 * Provers/hypsubst.ML: improved version of the subst method, for
   703 single-step rewriting: it now works in bound variable contexts. New is
   704 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   705 rewrite a different subterm than the original subst method, which is
   706 still available as 'simplesubst'.
   707 
   708 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   709 and quasi orders.
   710 
   711 * Provers/trancl.ML: new transitivity reasoner for transitive and
   712 reflexive-transitive closure of relations.
   713 
   714 * Provers/blast.ML: new reference depth_limit to make blast's depth
   715 limit (previously hard-coded with a value of 20) user-definable.
   716 
   717 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   718 is peformed already.  Object-logics merely need to finish their
   719 initial simpset configuration as before.  INCOMPATIBILITY.
   720 
   721 
   722 *** HOL ***
   723 
   724 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   725 
   726   syntax (epsilon)
   727     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   728 
   729 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   730 and x-symbol; use option '-m epsilon' to get it actually printed.
   731 Moreover, the mathematically important symbolic identifier \<epsilon>
   732 becomes available as variable, constant etc.  INCOMPATIBILITY,
   733 
   734 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   735 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   736 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
   737 support corresponding Isar calculations.
   738 
   739 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   740 instead of ":".
   741 
   742 * theory SetInterval: changed the syntax for open intervals:
   743 
   744   Old       New
   745   {..n(}    {..<n}
   746   {)n..}    {n<..}
   747   {m..n(}   {m..<n}
   748   {)m..n}   {m<..n}
   749   {)m..n(}  {m<..<n}
   750 
   751 The old syntax is still supported but will disappear in the next
   752 release.  For conversion use the following Emacs search and replace
   753 patterns (these are not perfect but work quite well):
   754 
   755   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   756   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   757 
   758 * Theory Commutative_Ring (in Library): method comm_ring for proving
   759 equalities in commutative rings; method 'algebra' provides a generic
   760 interface.
   761 
   762 * Theory Finite_Set: changed the syntax for 'setsum', summation over
   763 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   764 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
   765 be a tuple pattern.
   766 
   767 Some new syntax forms are available:
   768 
   769   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   770   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   771   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   772   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   773 
   774 The latter form "\<Sum>x < k. e" used to be based on a separate
   775 function "Summation", which has been discontinued.
   776 
   777 * theory Finite_Set: in structured induction proofs, the insert case
   778 is now 'case (insert x F)' instead of the old counterintuitive 'case
   779 (insert F x)'.
   780 
   781 * The 'refute' command has been extended to support a much larger
   782 fragment of HOL, including axiomatic type classes, constdefs and
   783 typedefs, inductive datatypes and recursion.
   784 
   785 * New tactics 'sat' and 'satx' to prove propositional tautologies.
   786 Requires zChaff with proof generation to be installed.  See
   787 HOL/ex/SAT_Examples.thy for examples.
   788 
   789 * Datatype induction via method 'induct' now preserves the name of the
   790 induction variable. For example, when proving P(xs::'a list) by
   791 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   792 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   793 in unstructured proof scripts.
   794 
   795 * Reworked implementation of records.  Improved scalability for
   796 records with many fields, avoiding performance problems for type
   797 inference. Records are no longer composed of nested field types, but
   798 of nested extension types. Therefore the record type only grows linear
   799 in the number of extensions and not in the number of fields.  The
   800 top-level (users) view on records is preserved.  Potential
   801 INCOMPATIBILITY only in strange cases, where the theory depends on the
   802 old record representation. The type generated for a record is called
   803 <record_name>_ext_type.
   804 
   805 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   806 proofs triggered by a record definition or a simproc (if
   807 quick_and_dirty is enabled).  Definitions of large records can take
   808 quite long.
   809 
   810 New simproc record_upd_simproc for simplification of multiple record
   811 updates enabled by default.  Moreover, trivial updates are also
   812 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   813 occasionally, since simplification is more powerful by default.
   814 
   815 * typedef: proper support for polymorphic sets, which contain extra
   816 type-variables in the term.
   817 
   818 * Simplifier: automatically reasons about transitivity chains
   819 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   820 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   821 old proofs break occasionally as simplification may now solve more
   822 goals than previously.
   823 
   824 * Simplifier: converts x <= y into x = y if assumption y <= x is
   825 present.  Works for all partial orders (class "order"), in particular
   826 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   827 just like y <= x.
   828 
   829 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   830 bound variable or a constant then the let is unfolded.  Otherwise
   831 first a is simplified to b, and then f b is simplified to g. If
   832 possible we abstract b from g arriving at "let x = b in h x",
   833 otherwise we unfold the let and arrive at g.  The simproc can be
   834 enabled/disabled by the reference use_let_simproc.  Potential
   835 INCOMPATIBILITY since simplification is more powerful by default.
   836 
   837 * Classical reasoning: the meson method now accepts theorems as arguments.
   838 
   839 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
   840 jobs to provide advice on the provability of subgoals.
   841 
   842 * Theory OrderedGroup and Ring_and_Field: various additions and
   843 improvements to faciliate calculations involving equalities and
   844 inequalities.
   845 
   846 The following theorems have been eliminated or modified
   847 (INCOMPATIBILITY):
   848 
   849   abs_eq             now named abs_of_nonneg
   850   abs_of_ge_0        now named abs_of_nonneg
   851   abs_minus_eq       now named abs_of_nonpos
   852   imp_abs_id         now named abs_of_nonneg
   853   imp_abs_neg_id     now named abs_of_nonpos
   854   mult_pos           now named mult_pos_pos
   855   mult_pos_le        now named mult_nonneg_nonneg
   856   mult_pos_neg_le    now named mult_nonneg_nonpos
   857   mult_pos_neg2_le   now named mult_nonneg_nonpos2
   858   mult_neg           now named mult_neg_neg
   859   mult_neg_le        now named mult_nonpos_nonpos
   860 
   861 * Theory Parity: added rules for simplifying exponents.
   862 
   863 * Theory List:
   864 
   865 The following theorems have been eliminated or modified
   866 (INCOMPATIBILITY):
   867 
   868   list_all_Nil       now named list_all.simps(1)
   869   list_all_Cons      now named list_all.simps(2)
   870   list_all_conv      now named list_all_iff
   871   set_mem_eq         now named mem_iff
   872 
   873 * Theories SetsAndFunctions and BigO (see HOL/Library) support
   874 asymptotic "big O" calculations.  See the notes in BigO.thy.
   875 
   876 
   877 *** HOL-Complex ***
   878 
   879 * Theory RealDef: better support for embedding natural numbers and
   880 integers in the reals.
   881 
   882 The following theorems have been eliminated or modified
   883 (INCOMPATIBILITY):
   884 
   885   exp_ge_add_one_self  now requires no hypotheses
   886   real_of_int_add      reversed direction of equality (use [symmetric])
   887   real_of_int_minus    reversed direction of equality (use [symmetric])
   888   real_of_int_diff     reversed direction of equality (use [symmetric])
   889   real_of_int_mult     reversed direction of equality (use [symmetric])
   890 
   891 * Theory RComplete: expanded support for floor and ceiling functions.
   892 
   893 * Theory Ln is new, with properties of the natural logarithm
   894 
   895 * Hyperreal: There is a new type constructor "star" for making
   896 nonstandard types.  The old type names are now type synonyms:
   897 
   898   hypreal = real star
   899   hypnat = nat star
   900   hcomplex = complex star
   901 
   902 * Hyperreal: Many groups of similarly-defined constants have been
   903 replaced by polymorphic versions (INCOMPATIBILITY):
   904 
   905   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
   906 
   907   starset      <-- starsetNat, starsetC
   908   *s*          <-- *sNat*, *sc*
   909   starset_n    <-- starsetNat_n, starsetC_n
   910   *sn*         <-- *sNatn*, *scn*
   911   InternalSets <-- InternalNatSets, InternalCSets
   912 
   913   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
   914   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
   915   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
   916   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
   917   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
   918 
   919 * Hyperreal: Many type-specific theorems have been removed in favor of
   920 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
   921 
   922   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
   923   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
   924   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
   925   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
   926   right_minus <-- hypreal_add_minus
   927   left_minus <-- {hypreal,hcomplex}_add_minus_left
   928   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
   929   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
   930   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
   931   mult_1_right <-- hcomplex_mult_one_right
   932   mult_zero_left <-- hcomplex_mult_zero_left
   933   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
   934   right_distrib <-- hypnat_add_mult_distrib2
   935   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
   936   right_inverse <-- hypreal_mult_inverse
   937   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
   938   order_refl <-- {hypreal,hypnat}_le_refl
   939   order_trans <-- {hypreal,hypnat}_le_trans
   940   order_antisym <-- {hypreal,hypnat}_le_anti_sym
   941   order_less_le <-- {hypreal,hypnat}_less_le
   942   linorder_linear <-- {hypreal,hypnat}_le_linear
   943   add_left_mono <-- {hypreal,hypnat}_add_left_mono
   944   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
   945   add_nonneg_nonneg <-- hypreal_le_add_order
   946 
   947 * Hyperreal: Separate theorems having to do with type-specific
   948 versions of constants have been merged into theorems that apply to the
   949 new polymorphic constants (INCOMPATIBILITY):
   950 
   951   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
   952   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
   953   STAR_Un <-- {STAR,NatStar,STARC}_Un
   954   STAR_Int <-- {STAR,NatStar,STARC}_Int
   955   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
   956   STAR_subset <-- {STAR,NatStar,STARC}_subset
   957   STAR_mem <-- {STAR,NatStar,STARC}_mem
   958   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
   959   STAR_diff <-- {STAR,STARC}_diff
   960   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
   961     STARC_hcomplex_of_complex}_image_subset
   962   starset_n_Un <-- starset{Nat,C}_n_Un
   963   starset_n_Int <-- starset{Nat,C}_n_Int
   964   starset_n_Compl <-- starset{Nat,C}_n_Compl
   965   starset_n_diff <-- starset{Nat,C}_n_diff
   966   InternalSets_Un <-- Internal{Nat,C}Sets_Un
   967   InternalSets_Int <-- Internal{Nat,C}Sets_Int
   968   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
   969   InternalSets_diff <-- Internal{Nat,C}Sets_diff
   970   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
   971   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
   972   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
   973   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
   974   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
   975   starfun <-- starfun{Nat,Nat2,C,RC,CR}
   976   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
   977   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
   978   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
   979   starfun_diff <-- starfun{C,RC,CR}_diff
   980   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
   981   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
   982   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
   983   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
   984   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
   985   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
   986   starfun_Id <-- starfunC_Id
   987   starfun_approx <-- starfun{Nat,CR}_approx
   988   starfun_capprox <-- starfun{C,RC}_capprox
   989   starfun_abs <-- starfunNat_rabs
   990   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
   991   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
   992   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
   993   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
   994   starfun_add_capprox <-- starfun{C,RC}_add_capprox
   995   starfun_add_approx <-- starfunCR_add_approx
   996   starfun_inverse_inverse <-- starfunC_inverse_inverse
   997   starfun_divide <-- starfun{C,CR,RC}_divide
   998   starfun_n <-- starfun{Nat,C}_n
   999   starfun_n_mult <-- starfun{Nat,C}_n_mult
  1000   starfun_n_add <-- starfun{Nat,C}_n_add
  1001   starfun_n_add_minus <-- starfunNat_n_add_minus
  1002   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  1003   starfun_n_minus <-- starfun{Nat,C}_n_minus
  1004   starfun_n_eq <-- starfun{Nat,C}_n_eq
  1005 
  1006   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  1007   star_n_minus <-- {hypreal,hcomplex}_minus
  1008   star_n_diff <-- {hypreal,hcomplex}_diff
  1009   star_n_mult <-- {hypreal,hcomplex}_mult
  1010   star_n_inverse <-- {hypreal,hcomplex}_inverse
  1011   star_n_le <-- {hypreal,hypnat}_le
  1012   star_n_less <-- {hypreal,hypnat}_less
  1013   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  1014   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  1015   star_n_abs <-- hypreal_hrabs
  1016   star_n_divide <-- hcomplex_divide
  1017 
  1018   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  1019   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  1020   star_of_diff <-- hypreal_of_real_diff
  1021   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  1022   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  1023   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  1024   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  1025   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  1026   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  1027   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  1028   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  1029   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  1030   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  1031   star_of_number_of <-- {hypreal,hcomplex}_number_of
  1032   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  1033   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  1034   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  1035   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  1036   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  1037   star_of_power <-- hypreal_of_real_power
  1038   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  1039 
  1040 * Hyperreal: new method "transfer" that implements the transfer
  1041 principle of nonstandard analysis. With a subgoal that mentions
  1042 nonstandard types like "'a star", the command "apply transfer"
  1043 replaces it with an equivalent one that mentions only standard types.
  1044 To be successful, all free variables must have standard types; non-
  1045 standard variables must have explicit universal quantifiers.
  1046 
  1047 * Hyperreal: A theory of Taylor series.
  1048 
  1049 
  1050 *** HOLCF ***
  1051 
  1052 * Discontinued special version of 'constdefs' (which used to support
  1053 continuous functions) in favor of the general Pure one with full
  1054 type-inference.
  1055 
  1056 * New simplification procedure for solving continuity conditions; it
  1057 is much faster on terms with many nested lambda abstractions (cubic
  1058 instead of exponential time).
  1059 
  1060 * New syntax for domain package: selector names are now optional.
  1061 Parentheses should be omitted unless argument is lazy, for example:
  1062 
  1063   domain 'a stream = cons "'a" (lazy "'a stream")
  1064 
  1065 * New command 'fixrec' for defining recursive functions with pattern
  1066 matching; defining multiple functions with mutual recursion is also
  1067 supported.  Patterns may include the constants cpair, spair, up, sinl,
  1068 sinr, or any data constructor defined by the domain package. The given
  1069 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  1070 syntax and examples.
  1071 
  1072 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  1073 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  1074 but the proof obligation additionally includes an admissibility
  1075 requirement. The packages generate instances of class cpo or pcpo,
  1076 with continuity and strictness theorems for Rep and Abs.
  1077 
  1078 * HOLCF: Many theorems have been renamed according to a more standard naming
  1079 scheme (INCOMPATIBILITY):
  1080 
  1081   foo_inject:  "foo$x = foo$y ==> x = y"
  1082   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1083   foo_less:    "(foo$x << foo$y) = (x << y)"
  1084   foo_strict:  "foo$UU = UU"
  1085   foo_defined: "... ==> foo$x ~= UU"
  1086   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1087 
  1088 
  1089 *** ZF ***
  1090 
  1091 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1092 including the First Isomorphism Theorem (on quotienting by the kernel
  1093 of a homomorphism).
  1094 
  1095 * ZF/Simplifier: install second copy of type solver that actually
  1096 makes use of TC rules declared to Isar proof contexts (or locales);
  1097 the old version is still required for ML proof scripts.
  1098 
  1099 
  1100 *** Cube ***
  1101 
  1102 * Converted to Isar theory format; use locales instead of axiomatic
  1103 theories.
  1104 
  1105 
  1106 *** ML ***
  1107 
  1108 * Pure/library.ML no longer defines its own option datatype, but uses
  1109 that of the SML basis, which has constructors NONE and SOME instead of
  1110 None and Some, as well as exception Option.Option instead of OPTION.
  1111 The functions the, if_none, is_some, is_none have been adapted
  1112 accordingly, while Option.map replaces apsome.
  1113 
  1114 * Pure/library.ML: the exception LIST has been given up in favour of
  1115 the standard exceptions Empty and Subscript, as well as
  1116 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1117 superceded by the standard hd and tl functions etc.
  1118 
  1119 A number of basic list functions are no longer exported to the ML
  1120 toplevel, as they are variants of predefined functions.  The following
  1121 suggests how one can translate existing code:
  1122 
  1123     rev_append xs ys = List.revAppend (xs, ys)
  1124     nth_elem (i, xs) = List.nth (xs, i)
  1125     last_elem xs = List.last xs
  1126     flat xss = List.concat xss
  1127     seq fs = List.app fs
  1128     partition P xs = List.partition P xs
  1129     mapfilter f xs = List.mapPartial f xs
  1130 
  1131 * Pure/library.ML: several combinators for linear functional
  1132 transformations, notably reverse application and composition:
  1133 
  1134   x |> f                f #> g
  1135   (x, y) |-> f          f #-> g
  1136 
  1137 * Pure/library.ML: introduced/changed precedence of infix operators:
  1138 
  1139   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1140   infix 2 ?;
  1141   infix 3 o oo ooo oooo;
  1142   infix 4 ~~ upto downto;
  1143 
  1144 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1145 infix operators.
  1146 
  1147 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1148 fold_map support linear functional transformations and nesting.  For
  1149 example:
  1150 
  1151   fold f [x1, ..., xN] y =
  1152     y |> f x1 |> ... |> f xN
  1153 
  1154   (fold o fold) f [xs1, ..., xsN] y =
  1155     y |> fold f xs1 |> ... |> fold f xsN
  1156 
  1157   fold f [x1, ..., xN] =
  1158     f x1 #> ... #> f xN
  1159 
  1160   (fold o fold) f [xs1, ..., xsN] =
  1161     fold f xs1 #> ... #> fold f xsN
  1162 
  1163 * Pure/library.ML: the following selectors on type 'a option are
  1164 available:
  1165 
  1166   the:               'a option -> 'a  (*partial*)
  1167   these:             'a option -> 'a  where 'a = 'b list
  1168   the_default: 'a -> 'a option -> 'a
  1169   the_list:          'a option -> 'a list
  1170 
  1171 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1172 basic operations for association lists, following natural argument
  1173 order; moreover the explicit equality predicate passed here avoids
  1174 potentially expensive polymorphic runtime equality checks.
  1175 The old functions may be expressed as follows:
  1176 
  1177   assoc = uncurry (AList.lookup (op =))
  1178   assocs = these oo AList.lookup (op =)
  1179   overwrite = uncurry (AList.update (op =)) o swap
  1180 
  1181 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1182 
  1183   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1184   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1185 
  1186 replacing make_keylist and keyfilter (occassionally used)
  1187 Naive rewrites:
  1188 
  1189   make_keylist = AList.make
  1190   keyfilter = AList.find (op =)
  1191 
  1192 * eq_fst and eq_snd now take explicit equality parameter, thus
  1193   avoiding eqtypes. Naive rewrites:
  1194 
  1195     eq_fst = eq_fst (op =)
  1196     eq_snd = eq_snd (op =)
  1197 
  1198 * Removed deprecated apl and apr (rarely used).
  1199   Naive rewrites:
  1200 
  1201     apl (n, op) =>>= curry op n
  1202     apr (op, m) =>>= fn n => op (n, m)
  1203 
  1204 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1205 provides a reasonably efficient light-weight implementation of sets as
  1206 lists.
  1207 
  1208 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1209 few new operations; existing lookup and update are now curried to
  1210 follow natural argument order (for use with fold etc.);
  1211 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1212 
  1213 * Pure/General: output via the Isabelle channels of
  1214 writeln/warning/error etc. is now passed through Output.output, with a
  1215 hook for arbitrary transformations depending on the print_mode
  1216 (cf. Output.add_mode -- the first active mode that provides a output
  1217 function wins).  Already formatted output may be embedded into further
  1218 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1219 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1220 accommodate easy composition of diagnostic messages etc.  Programmers
  1221 rarely need to care about Output.output or Output.raw at all, with
  1222 some notable exceptions: Output.output is required when bypassing the
  1223 standard channels (writeln etc.), or in token translations to produce
  1224 properly formatted results; Output.raw is required when capturing
  1225 already output material that will eventually be presented to the user
  1226 a second time.  For the default print mode, both Output.output and
  1227 Output.raw have no effect.
  1228 
  1229 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1230 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1231 cumulative results are displayed at the end of a batch session.
  1232 
  1233 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1234 replaced by File.platform_path and File.shell_path (with appropriate
  1235 hooks).  This provides a clean interface for unusual systems where the
  1236 internal and external process view of file names are different.
  1237 
  1238 * Pure: more efficient orders for basic syntactic entities: added
  1239 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1240 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1241 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1242 orders now -- potential INCOMPATIBILITY for code that depends on a
  1243 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1244 Library.sort_strings on result).
  1245 
  1246 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1247 fold_types traverse types/terms from left to right, observing natural
  1248 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1249 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1250 
  1251 * Pure: name spaces have been refined, with significant changes of the
  1252 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1253 to extern(_table).  The plain name entry path is superceded by a
  1254 general 'naming' context, which also includes the 'policy' to produce
  1255 a fully qualified name and external accesses of a fully qualified
  1256 name; NameSpace.extend is superceded by context dependent
  1257 Sign.declare_name.  Several theory and proof context operations modify
  1258 the naming context.  Especially note Theory.restore_naming and
  1259 ProofContext.restore_naming to get back to a sane state; note that
  1260 Theory.add_path is no longer sufficient to recover from
  1261 Theory.absolute_path in particular.
  1262 
  1263 * Pure: new flags short_names (default false) and unique_names
  1264 (default true) for controlling output of qualified names.  If
  1265 short_names is set, names are printed unqualified.  If unique_names is
  1266 reset, the name prefix is reduced to the minimum required to achieve
  1267 the original result when interning again, even if there is an overlap
  1268 with earlier declarations.
  1269 
  1270 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1271 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1272 (useful for printing error messages).  INCOMPATIBILITY.
  1273 
  1274 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1275 Theory.theory are now identified, referring to the universal
  1276 Context.theory (see Pure/context.ML).  Actual signature and theory
  1277 content is managed as theory data.  The old code and interfaces were
  1278 spread over many files and structures; the new arrangement introduces
  1279 considerable INCOMPATIBILITY to gain more clarity:
  1280 
  1281   Context -- theory management operations (name, identity, inclusion,
  1282     parents, ancestors, merge, etc.), plus generic theory data;
  1283 
  1284   Sign -- logical signature and syntax operations (declaring consts,
  1285     types, etc.), plus certify/read for common entities;
  1286 
  1287   Theory -- logical theory operations (stating axioms, definitions,
  1288     oracles), plus a copy of logical signature operations (consts,
  1289     types, etc.); also a few basic management operations (Theory.copy,
  1290     Theory.merge, etc.)
  1291 
  1292 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1293 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1294 for convenience -- they merely return the theory.
  1295 
  1296 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1297 
  1298 * Pure: the Isar proof context type is already defined early in Pure
  1299 as Context.proof (note that ProofContext.context and Proof.context are
  1300 aliases, where the latter is the preferred name).  This enables other
  1301 Isabelle components to refer to that type even before Isar is present.
  1302 
  1303 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1304 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1305 any of these kinds.  For example, Sign.intern typeK is now
  1306 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1307 Theory.hide_types.  Also note that former
  1308 Theory.hide_classes/types/consts are now
  1309 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1310 internalize their arguments!  INCOMPATIBILITY.
  1311 
  1312 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1313 datatype thmref (with constructors Name and NameSelection) instead of
  1314 plain string -- INCOMPATIBILITY;
  1315 
  1316 * Pure: cases produced by proof methods specify options, where NONE
  1317 means to remove case bindings -- INCOMPATIBILITY in
  1318 (RAW_)METHOD_CASES.
  1319 
  1320 * Pure: the following operations retrieve axioms or theorems from a
  1321 theory node or theory hierarchy, respectively:
  1322 
  1323   Theory.axioms_of: theory -> (string * term) list
  1324   Theory.all_axioms_of: theory -> (string * term) list
  1325   PureThy.thms_of: theory -> (string * thm) list
  1326   PureThy.all_thms_of: theory -> (string * thm) list
  1327 
  1328 * Pure: print_tac now outputs the goal through the trace channel.
  1329 
  1330 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1331 Reference Toplevel.debug (default false) controls detailed printing
  1332 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1333 controls execution profiling -- set to 1 for time and 2 for space
  1334 (both increase the runtime).
  1335 
  1336 * Isar session: The initial use of ROOT.ML is now always timed,
  1337 i.e. the log will show the actual process times, in contrast to the
  1338 elapsed wall-clock time that the outer shell wrapper produces.
  1339 
  1340 * Simplifier: improved handling of bound variables (nameless
  1341 representation, avoid allocating new strings).  Simprocs that invoke
  1342 the Simplifier recursively should use Simplifier.inherit_bounds to
  1343 avoid local name clashes.  Failure to do so produces warnings
  1344 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1345 for further details.
  1346 
  1347 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1348 bindings for all theorems stored within a given theory; this may help
  1349 in porting non-Isar theories to Isar ones, while keeping ML proof
  1350 scripts for the time being.
  1351 
  1352 * ML operator HTML.with_charset specifies the charset begin used for
  1353 generated HTML files.  For example:
  1354 
  1355   HTML.with_charset "utf-8" use_thy "Hebrew";
  1356   HTML.with_charset "utf-8" use_thy "Chinese";
  1357 
  1358 
  1359 *** System ***
  1360 
  1361 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1362 isabelle, isatool etc.).
  1363 
  1364 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1365 isatool doc, isatool mkdir, display_drafts etc.).
  1366 
  1367 * isatool usedir: option -f allows specification of the ML file to be
  1368 used by Isabelle; default is ROOT.ML.
  1369 
  1370 * New isatool version outputs the version identifier of the Isabelle
  1371 distribution being used.
  1372 
  1373 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1374 (containing Boolean satisfiability problems) into Isabelle/HOL
  1375 theories.
  1376 
  1377 
  1378 
  1379 New in Isabelle2004 (April 2004)
  1380 --------------------------------
  1381 
  1382 *** General ***
  1383 
  1384 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1385   Replaces linorder.ML.
  1386 
  1387 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1388   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1389   (\<a>...\<z>), are now considered normal letters, and can therefore
  1390   be used anywhere where an ASCII letter (a...zA...Z) has until
  1391   now. COMPATIBILITY: This obviously changes the parsing of some
  1392   terms, especially where a symbol has been used as a binder, say
  1393   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1394   as an identifier.  Fix it by inserting a space around former
  1395   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1396   existing theory and ML files.
  1397 
  1398 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1399 
  1400 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1401   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1402   a normal (but invisible) letter. For multiple letter subscripts repeat
  1403   \<^isub> like this: x\<^isub>1\<^isub>2.
  1404 
  1405 * Pure: There are now sub-/superscripts that can span more than one
  1406   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1407   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1408   superscript. The new control characters are not identifier parts.
  1409 
  1410 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1411   content of "..." to the latex file instead of \isacntrl... . The "..."
  1412   may consist of any printable characters excluding the end bracket >.
  1413 
  1414 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1415   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1416   declare constants "final", which prevents their being given a definition
  1417   later.  It is useful for constants whose behaviour is fixed axiomatically
  1418   rather than definitionally, such as the meta-logic connectives.
  1419 
  1420 * Pure: 'instance' now handles general arities with general sorts
  1421   (i.e. intersections of classes),
  1422 
  1423 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1424   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1425   It can be changed to alter the colors/layout of generated pages.
  1426 
  1427 
  1428 *** Isar ***
  1429 
  1430 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1431   cut_tac, subgoal_tac and thin_tac:
  1432   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1433     locales are no longer forced to write Isar proof scripts.
  1434     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1435     emulations.
  1436   - INCOMPATIBILITY: names of variables to be instantiated may no
  1437     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1438     This is consistent with the instantiation attribute "where".
  1439 
  1440 * Attributes "where" and "of":
  1441   - Now take type variables of instantiated theorem into account when reading
  1442     the instantiation string.  This fixes a bug that caused instantiated
  1443     theorems to have too special types in some circumstances.
  1444   - "where" permits explicit instantiations of type variables.
  1445 
  1446 * Calculation commands "moreover" and "also" no longer interfere with
  1447   current facts ("this"), admitting arbitrary combinations with "then"
  1448   and derived forms.
  1449 
  1450 * Locales:
  1451   - Goal statements involving the context element "includes" no longer
  1452     generate theorems with internal delta predicates (those ending on
  1453     "_axioms") in the premise.
  1454     Resolve particular premise with <locale>.intro to obtain old form.
  1455   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1456     specification and "includes" elements in goal statement.
  1457   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1458     [intro?] and [elim?] (respectively) by default.
  1459   - Experimental command for instantiation of locales in proof contexts:
  1460         instantiate <label>[<attrs>]: <loc>
  1461     Instantiates locale <loc> and adds all its theorems to the current context
  1462     taking into account their attributes.  Label and attrs are optional
  1463     modifiers, like in theorem declarations.  If present, names of
  1464     instantiated theorems are qualified with <label>, and the attributes
  1465     <attrs> are applied after any attributes these theorems might have already.
  1466       If the locale has assumptions, a chained fact of the form
  1467     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1468     are derived.  The command does not support old-style locales declared
  1469     with "locale (open)".
  1470       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1471 
  1472 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1473   (Isar) contexts.
  1474 
  1475 
  1476 *** HOL ***
  1477 
  1478 * Proof import: new image HOL4 contains the imported library from
  1479   the HOL4 system with about 2500 theorems. It is imported by
  1480   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1481   can be used like any other Isabelle image.  See
  1482   HOL/Import/HOL/README for more information.
  1483 
  1484 * Simplifier:
  1485   - Much improved handling of linear and partial orders.
  1486     Reasoners for linear and partial orders are set up for type classes
  1487     "linorder" and "order" respectively, and are added to the default simpset
  1488     as solvers.  This means that the simplifier can build transitivity chains
  1489     to solve goals from the assumptions.
  1490   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1491     of blast or auto after simplification become unnecessary because the goal
  1492     is solved by simplification already.
  1493 
  1494 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1495     all proved in axiomatic type classes for semirings, rings and fields.
  1496 
  1497 * Numerics:
  1498   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1499     now formalized using the Ring_and_Field theory mentioned above.
  1500   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1501     than before, because now they are set up once in a generic manner.
  1502   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1503     Look for the general versions in Ring_and_Field (and Power if they concern
  1504     exponentiation).
  1505 
  1506 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1507 
  1508 * Records:
  1509   - Record types are now by default printed with their type abbreviation
  1510     instead of the list of all field types. This can be configured via
  1511     the reference "print_record_type_abbr".
  1512   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1513     (not enabled by default).
  1514   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1515     EX x. x = sel r to True (not enabled by default).
  1516   - Tactic "record_split_simp_tac" to split and simplify records added.
  1517 
  1518 * 'specification' command added, allowing for definition by
  1519   specification.  There is also an 'ax_specification' command that
  1520   introduces the new constants axiomatically.
  1521 
  1522 * arith(_tac) is now able to generate counterexamples for reals as well.
  1523 
  1524 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1525 
  1526 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1527   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1528 
  1529 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1530   matrix theory to linear programming.
  1531 
  1532 * Unions and Intersections:
  1533   The latex output syntax of UN and INT has been changed
  1534   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1535   i.e. the index formulae has become a subscript.
  1536   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1537 
  1538 * Unions and Intersections over Intervals:
  1539   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1540   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1541   like in normal math, and corresponding versions for < and for intersection.
  1542 
  1543 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1544   lexicographic dictonary ordering has been added as "lexord".
  1545 
  1546 * ML: the legacy theory structures Int and List have been removed. They had
  1547   conflicted with ML Basis Library structures having the same names.
  1548 
  1549 * 'refute' command added to search for (finite) countermodels.  Only works
  1550   for a fragment of HOL.  The installation of an external SAT solver is
  1551   highly recommended.  See "HOL/Refute.thy" for details.
  1552 
  1553 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1554   formulae under an assignment of free variables to random values.
  1555   In contrast to 'refute', it can deal with inductive datatypes,
  1556   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1557   for examples.
  1558 
  1559 
  1560 *** HOLCF ***
  1561 
  1562 * Streams now come with concatenation and are part of the HOLCF image
  1563 
  1564 
  1565 
  1566 New in Isabelle2003 (May 2003)
  1567 ------------------------------
  1568 
  1569 *** General ***
  1570 
  1571 * Provers/simplifier:
  1572 
  1573   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1574     Assumptions are now subject to complete mutual simplification,
  1575     not just from left to right. The simplifier now preserves
  1576     the order of assumptions.
  1577 
  1578     Potential INCOMPATIBILITY:
  1579 
  1580     -- simp sometimes diverges where the old version did
  1581        not, e.g. invoking simp on the goal
  1582 
  1583         [| P (f x); y = x; f x = f y |] ==> Q
  1584 
  1585        now gives rise to the infinite reduction sequence
  1586 
  1587         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1588 
  1589        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1590        kind of problem.
  1591 
  1592     -- Tactics combining classical reasoner and simplification (such as auto)
  1593        are also affected by this change, because many of them rely on
  1594        simp. They may sometimes diverge as well or yield a different numbers
  1595        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1596        in case of problems. Sometimes subsequent calls to the classical
  1597        reasoner will fail because a preceeding call to the simplifier too
  1598        eagerly simplified the goal, e.g. deleted redundant premises.
  1599 
  1600   - The simplifier trace now shows the names of the applied rewrite rules
  1601 
  1602   - You can limit the number of recursive invocations of the simplifier
  1603     during conditional rewriting (where the simplifie tries to solve the
  1604     conditions before applying the rewrite rule):
  1605     ML "simp_depth_limit := n"
  1606     where n is an integer. Thus you can force termination where previously
  1607     the simplifier would diverge.
  1608 
  1609   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1610 
  1611   - No longer aborts on failed congruence proof.  Instead, the
  1612     congruence is ignored.
  1613 
  1614 * Pure: New generic framework for extracting programs from constructive
  1615   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1616   as HOL/Extraction for some case studies.
  1617 
  1618 * Pure: The main goal of the proof state is no longer shown by default, only
  1619 the subgoals. This behaviour is controlled by a new flag.
  1620    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1621 (ML: Proof.show_main_goal).
  1622 
  1623 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1624 rules whose conclusion matches subgoal 1:
  1625       PG menu: Isabelle/Isar -> Show me -> matching rules
  1626 The rules are ordered by how closely they match the subgoal.
  1627 In particular, rules that solve a subgoal outright are displayed first
  1628 (or rather last, the way they are printed).
  1629 (ML: ProofGeneral.print_intros())
  1630 
  1631 * Pure: New flag trace_unify_fail causes unification to print
  1632 diagnostic information (PG: in trace buffer) when it fails. This is
  1633 useful for figuring out why single step proofs like rule, erule or
  1634 assumption failed.
  1635 
  1636 * Pure: Locale specifications now produce predicate definitions
  1637 according to the body of text (covering assumptions modulo local
  1638 definitions); predicate "loc_axioms" covers newly introduced text,
  1639 while "loc" is cumulative wrt. all included locale expressions; the
  1640 latter view is presented only on export into the global theory
  1641 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1642 on the old view without predicates;
  1643 
  1644 * Pure: predefined locales "var" and "struct" are useful for sharing
  1645 parameters (as in CASL, for example); just specify something like
  1646 ``var x + var y + struct M'' as import;
  1647 
  1648 * Pure: improved thms_containing: proper indexing of facts instead of
  1649 raw theorems; check validity of results wrt. current name space;
  1650 include local facts of proof configuration (also covers active
  1651 locales), cover fixed variables in index; may use "_" in term
  1652 specification; an optional limit for the number of printed facts may
  1653 be given (the default is 40);
  1654 
  1655 * Pure: disallow duplicate fact bindings within new-style theory files
  1656 (batch-mode only);
  1657 
  1658 * Provers: improved induct method: assumptions introduced by case
  1659 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1660 the goal statement); "foo" still refers to all facts collectively;
  1661 
  1662 * Provers: the function blast.overloaded has been removed: all constants
  1663 are regarded as potentially overloaded, which improves robustness in exchange
  1664 for slight decrease in efficiency;
  1665 
  1666 * Provers/linorder: New generic prover for transitivity reasoning over
  1667 linear orders.  Note: this prover is not efficient!
  1668 
  1669 * Isar: preview of problems to finish 'show' now produce an error
  1670 rather than just a warning (in interactive mode);
  1671 
  1672 
  1673 *** HOL ***
  1674 
  1675 * arith(_tac)
  1676 
  1677  - Produces a counter example if it cannot prove a goal.
  1678    Note that the counter example may be spurious if the goal is not a formula
  1679    of quantifier-free linear arithmetic.
  1680    In ProofGeneral the counter example appears in the trace buffer.
  1681 
  1682  - Knows about div k and mod k where k is a numeral of type nat or int.
  1683 
  1684  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1685    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1686    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1687 
  1688 * simp's arithmetic capabilities have been enhanced a bit: it now
  1689 takes ~= in premises into account (by performing a case split);
  1690 
  1691 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  1692 are distributed over a sum of terms;
  1693 
  1694 * New tactic "trans_tac" and method "trans" instantiate
  1695 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  1696 "<=", "<" and "=").
  1697 
  1698 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  1699 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  1700 
  1701 * 'typedef' command has new option "open" to suppress the set
  1702 definition;
  1703 
  1704 * functions Min and Max on finite sets have been introduced (theory
  1705 Finite_Set);
  1706 
  1707 * attribute [symmetric] now works for relations as well; it turns
  1708 (x,y) : R^-1 into (y,x) : R, and vice versa;
  1709 
  1710 * induct over a !!-quantified statement (say !!x1..xn):
  1711   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  1712 
  1713 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1714 %x. None. Warning: empty_def now refers to the previously hidden definition
  1715 of the empty set.
  1716 
  1717 * Algebra: formalization of classical algebra.  Intended as base for
  1718 any algebraic development in Isabelle.  Currently covers group theory
  1719 (up to Sylow's theorem) and ring theory (Universal Property of
  1720 Univariate Polynomials).  Contributions welcome;
  1721 
  1722 * GroupTheory: deleted, since its material has been moved to Algebra;
  1723 
  1724 * Complex: new directory of the complex numbers with numeric constants,
  1725 nonstandard complex numbers, and some complex analysis, standard and
  1726 nonstandard (Jacques Fleuriot);
  1727 
  1728 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1729 
  1730 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1731 Fleuriot);
  1732 
  1733 * Real/HahnBanach: updated and adapted to locales;
  1734 
  1735 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1736 Gray and Kramer);
  1737 
  1738 * UNITY: added the Meier-Sanders theory of progress sets;
  1739 
  1740 * MicroJava: bytecode verifier and lightweight bytecode verifier
  1741 as abstract algorithms, instantiated to the JVM;
  1742 
  1743 * Bali: Java source language formalization. Type system, operational
  1744 semantics, axiomatic semantics. Supported language features:
  1745 classes, interfaces, objects,virtual methods, static methods,
  1746 static/instance fields, arrays, access modifiers, definite
  1747 assignment, exceptions.
  1748 
  1749 
  1750 *** ZF ***
  1751 
  1752 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  1753 universe, etc.);
  1754 
  1755 * Main ZF: virtually all theories converted to new-style format;
  1756 
  1757 
  1758 *** ML ***
  1759 
  1760 * Pure: Tactic.prove provides sane interface for internal proofs;
  1761 omits the infamous "standard" operation, so this is more appropriate
  1762 than prove_goalw_cterm in many situations (e.g. in simprocs);
  1763 
  1764 * Pure: improved error reporting of simprocs;
  1765 
  1766 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  1767 up simprocs;
  1768 
  1769 
  1770 *** Document preparation ***
  1771 
  1772 * uses \par instead of \\ for line breaks in theory text. This may
  1773 shift some page breaks in large documents. To get the old behaviour
  1774 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  1775 
  1776 * minimized dependencies of isabelle.sty and isabellesym.sty on
  1777 other packages
  1778 
  1779 * \<euro> now needs package babel/greek instead of marvosym (which
  1780 broke \Rightarrow)
  1781 
  1782 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  1783 textcomp package)
  1784 
  1785 
  1786 
  1787 New in Isabelle2002 (March 2002)
  1788 --------------------------------
  1789 
  1790 *** Document preparation ***
  1791 
  1792 * greatly simplified document preparation setup, including more
  1793 graceful interpretation of isatool usedir -i/-d/-D options, and more
  1794 instructive isatool mkdir; users should basically be able to get
  1795 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  1796 users may run a separate document processing stage manually like this:
  1797 "isatool usedir -D output HOL Test && isatool document Test/output";
  1798 
  1799 * theory dependency graph may now be incorporated into documents;
  1800 isatool usedir -g true will produce session_graph.eps/.pdf for use
  1801 with \includegraphics of LaTeX;
  1802 
  1803 * proper spacing of consecutive markup elements, especially text
  1804 blocks after section headings;
  1805 
  1806 * support bold style (for single symbols only), input syntax is like
  1807 this: "\<^bold>\<alpha>" or "\<^bold>A";
  1808 
  1809 * \<bullet> is now output as bold \cdot by default, which looks much
  1810 better in printed text;
  1811 
  1812 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  1813 note that these symbols are currently unavailable in Proof General /
  1814 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  1815 
  1816 * isatool latex no longer depends on changed TEXINPUTS, instead
  1817 isatool document copies the Isabelle style files to the target
  1818 location;
  1819 
  1820 
  1821 *** Isar ***
  1822 
  1823 * Pure/Provers: improved proof by cases and induction;
  1824   - 'case' command admits impromptu naming of parameters (such as
  1825     "case (Suc n)");
  1826   - 'induct' method divinates rule instantiation from the inductive
  1827     claim; no longer requires excessive ?P bindings for proper
  1828     instantiation of cases;
  1829   - 'induct' method properly enumerates all possibilities of set/type
  1830     rules; as a consequence facts may be also passed through *type*
  1831     rules without further ado;
  1832   - 'induct' method now derives symbolic cases from the *rulified*
  1833     rule (before it used to rulify cases stemming from the internal
  1834     atomized version); this means that the context of a non-atomic
  1835     statement becomes is included in the hypothesis, avoiding the
  1836     slightly cumbersome show "PROP ?case" form;
  1837   - 'induct' may now use elim-style induction rules without chaining
  1838     facts, using ``missing'' premises from the goal state; this allows
  1839     rules stemming from inductive sets to be applied in unstructured
  1840     scripts, while still benefitting from proper handling of non-atomic
  1841     statements; NB: major inductive premises need to be put first, all
  1842     the rest of the goal is passed through the induction;
  1843   - 'induct' proper support for mutual induction involving non-atomic
  1844     rule statements (uses the new concept of simultaneous goals, see
  1845     below);
  1846   - append all possible rule selections, but only use the first
  1847     success (no backtracking);
  1848   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1849   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1850   - added 'print_induct_rules' (covered by help item in recent Proof
  1851     General versions);
  1852   - moved induct/cases attributes to Pure, methods to Provers;
  1853   - generic method setup instantiated for FOL and HOL;
  1854 
  1855 * Pure: support multiple simultaneous goal statements, for example
  1856 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1857 meta-level mechanism, this acts as if several individual goals had
  1858 been stated separately; in particular common proof methods need to be
  1859 repeated in order to cover all claims; note that a single elimination
  1860 step is *not* sufficient to establish the two conjunctions, so this
  1861 fails:
  1862 
  1863   assume "A & B" then have A and B ..   (*".." fails*)
  1864 
  1865 better use "obtain" in situations as above; alternative refer to
  1866 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1867 
  1868 * Pure: proper integration with ``locales''; unlike the original
  1869 version by Florian Kammller, Isar locales package high-level proof
  1870 contexts rather than raw logical ones (e.g. we admit to include
  1871 attributes everywhere); operations on locales include merge and
  1872 rename; support for implicit arguments (``structures''); simultaneous
  1873 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1874 some examples;
  1875 
  1876 * Pure: the following commands have been ``localized'', supporting a
  1877 target locale specification "(in name)": 'lemma', 'theorem',
  1878 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1879 stored both within the locale and at the theory level (exported and
  1880 qualified by the locale name);
  1881 
  1882 * Pure: theory goals may now be specified in ``long'' form, with
  1883 ad-hoc contexts consisting of arbitrary locale elements. for example
  1884 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1885 definitions may be given, too); the result is a meta-level rule with
  1886 the context elements being discharged in the obvious way;
  1887 
  1888 * Pure: new proof command 'using' allows to augment currently used
  1889 facts after a goal statement ('using' is syntactically analogous to
  1890 'apply', but acts on the goal's facts only); this allows chained facts
  1891 to be separated into parts given before and after a claim, as in
  1892 ``from a and b have C using d and e <proof>'';
  1893 
  1894 * Pure: renamed "antecedent" case to "rule_context";
  1895 
  1896 * Pure: new 'judgment' command records explicit information about the
  1897 object-logic embedding (used by several tools internally); no longer
  1898 use hard-wired "Trueprop";
  1899 
  1900 * Pure: added 'corollary' command;
  1901 
  1902 * Pure: fixed 'token_translation' command;
  1903 
  1904 * Pure: removed obsolete 'exported' attribute;
  1905 
  1906 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1907 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1908 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1909 
  1910 * Pure: method 'atomize' presents local goal premises as object-level
  1911 statements (atomic meta-level propositions); setup controlled via
  1912 rewrite rules declarations of 'atomize' attribute; example
  1913 application: 'induct' method with proper rule statements in improper
  1914 proof *scripts*;
  1915 
  1916 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1917 now consider the syntactic context of assumptions, giving a better
  1918 chance to get type-inference of the arguments right (this is
  1919 especially important for locales);
  1920 
  1921 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1922 mode;
  1923 
  1924 * Pure/obtain: the formal conclusion "thesis", being marked as
  1925 ``internal'', may no longer be reference directly in the text;
  1926 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1927 situations;
  1928 
  1929 * Pure: generic 'sym' attribute which declares a rule both as pure
  1930 'elim?' and for the 'symmetric' operation;
  1931 
  1932 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1933 text; the fixed correlation with particular command syntax has been
  1934 discontinued;
  1935 
  1936 * Pure: new method 'rules' is particularly well-suited for proof
  1937 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1938 but often produces more compact proof terms with less detours;
  1939 
  1940 * Pure/Provers/classical: simplified integration with pure rule
  1941 attributes and methods; the classical "intro?/elim?/dest?"
  1942 declarations coincide with the pure ones; the "rule" method no longer
  1943 includes classically swapped intros; "intro" and "elim" methods no
  1944 longer pick rules from the context; also got rid of ML declarations
  1945 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1946 INCOMPATIBILITY;
  1947 
  1948 * Provers/classical: attribute 'swapped' produces classical inversions
  1949 of introduction rules;
  1950 
  1951 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1952 rules instead of full simplifier context; 'iff' attribute handles
  1953 conditional rules;
  1954 
  1955 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1956 
  1957 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1958 "(permissive)" option to recover old behavior;
  1959 
  1960 * HOL: 'inductive' no longer features separate (collective) attributes
  1961 for 'intros' (was found too confusing);
  1962 
  1963 * HOL: properly declared induction rules less_induct and
  1964 wf_induct_rule;
  1965 
  1966 
  1967 *** HOL ***
  1968 
  1969 * HOL: moved over to sane numeral syntax; the new policy is as
  1970 follows:
  1971 
  1972   - 0 and 1 are polymorphic constants, which are defined on any
  1973   numeric type (nat, int, real etc.);
  1974 
  1975   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1976   binary representation internally;
  1977 
  1978   - type nat has special constructor Suc, and generally prefers Suc 0
  1979   over 1::nat and Suc (Suc 0) over 2::nat;
  1980 
  1981 This change may cause significant problems of INCOMPATIBILITY; here
  1982 are some hints on converting existing sources:
  1983 
  1984   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1985   entities, so expressions involving "-" (unary or binary minus) need
  1986   to be spaced properly;
  1987 
  1988   - existing occurrences of "1" may need to be constraint "1::nat" or
  1989   even replaced by Suc 0; similar for old "2";
  1990 
  1991   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1992 
  1993   - remove all special provisions on numerals in proofs;
  1994 
  1995 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1996 representation (depends on bin_arith_simps in the default context);
  1997 
  1998 * HOL: symbolic syntax for x^2 (numeral 2);
  1999 
  2000 * HOL: the class of all HOL types is now called "type" rather than
  2001 "term"; INCOMPATIBILITY, need to adapt references to this type class
  2002 in axclass/classes, instance/arities, and (usually rare) occurrences
  2003 in typings (of consts etc.); internally the class is called
  2004 "HOL.type", ML programs should refer to HOLogic.typeS;
  2005 
  2006 * HOL/record package improvements:
  2007   - new derived operations "fields" to build a partial record section,
  2008     "extend" to promote a fixed record to a record scheme, and
  2009     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  2010     declared as simp by default;
  2011   - shared operations ("more", "fields", etc.) now need to be always
  2012     qualified) --- potential INCOMPATIBILITY;
  2013   - removed "make_scheme" operations (use "make" with "extend") --
  2014     INCOMPATIBILITY;
  2015   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  2016   - provides cases/induct rules for use with corresponding Isar
  2017     methods (for concrete records, record schemes, concrete more
  2018     parts, and schematic more parts -- in that order);
  2019   - internal definitions directly based on a light-weight abstract
  2020     theory of product types over typedef rather than datatype;
  2021 
  2022 * HOL: generic code generator for generating executable ML code from
  2023 specifications; specific support for HOL constructs such as inductive
  2024 datatypes and sets, as well as recursive functions; can be invoked
  2025 via 'generate_code' theory section;
  2026 
  2027 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  2028 
  2029 * HOL: consolidated and renamed several theories.  In particular:
  2030         Ord.thy has been absorbed into HOL.thy
  2031         String.thy has been absorbed into List.thy
  2032 
  2033 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  2034 (beware of argument permutation!);
  2035 
  2036 * HOL: linorder_less_split superseded by linorder_cases;
  2037 
  2038 * HOL/List: "nodups" renamed to "distinct";
  2039 
  2040 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  2041 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  2042   - Ex_def has changed, now need to use some_eq_ex
  2043 
  2044 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  2045 in this (rare) case use:
  2046 
  2047   delSWrapper "split_all_tac"
  2048   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  2049 
  2050 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  2051 MAY FAIL;
  2052 
  2053 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  2054 Isabelle's type classes, ^ on functions and relations has too general
  2055 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  2056 necessary to attach explicit type constraints;
  2057 
  2058 * HOL/Relation: the prefix name of the infix "O" has been changed from
  2059 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  2060 renamed accordingly (eg "compI" -> "rel_compI").
  2061 
  2062 * HOL: syntax translations now work properly with numerals and records
  2063 expressions;
  2064 
  2065 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  2066 of "lam" -- INCOMPATIBILITY;
  2067 
  2068 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  2069 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  2070 renamed "Product_Type.unit";
  2071 
  2072 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  2073 
  2074 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  2075 the "cases" method);
  2076 
  2077 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  2078 Florian Kammller);
  2079 
  2080 * HOL/IMP: updated and converted to new-style theory format; several
  2081 parts turned into readable document, with proper Isar proof texts and
  2082 some explanations (by Gerwin Klein);
  2083 
  2084 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2085 
  2086 * HOL-Hyperreal is now a logic image;
  2087 
  2088 
  2089 *** HOLCF ***
  2090 
  2091 * Isar: consts/constdefs supports mixfix syntax for continuous
  2092 operations;
  2093 
  2094 * Isar: domain package adapted to new-style theory format, e.g. see
  2095 HOLCF/ex/Dnat.thy;
  2096 
  2097 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2098 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2099 lift.induct_tac, always use UU instead of Undef;
  2100 
  2101 * HOLCF/IMP: updated and converted to new-style theory;
  2102 
  2103 
  2104 *** ZF ***
  2105 
  2106 * Isar: proper integration of logic-specific tools and packages,
  2107 including theory commands '(co)inductive', '(co)datatype',
  2108 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2109 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2110 
  2111 * theory Main no longer includes AC; for the Axiom of Choice, base
  2112 your theory on Main_ZFC;
  2113 
  2114 * the integer library now covers quotients and remainders, with many
  2115 laws relating division to addition, multiplication, etc.;
  2116 
  2117 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2118 typeless version of the formalism;
  2119 
  2120 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2121 format;
  2122 
  2123 * ZF/Induct: new directory for examples of inductive definitions,
  2124 including theory Multiset for multiset orderings; converted to
  2125 new-style theory format;
  2126 
  2127 * ZF: many new theorems about lists, ordinals, etc.;
  2128 
  2129 
  2130 *** General ***
  2131 
  2132 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2133 variable proof controls level of detail: 0 = no proofs (only oracle
  2134 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2135 also ref manual for further ML interfaces;
  2136 
  2137 * Pure/axclass: removed obsolete ML interface
  2138 goal_subclass/goal_arity;
  2139 
  2140 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2141 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2142 separate tokens, so expressions involving minus need to be spaced
  2143 properly;
  2144 
  2145 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2146 rather than "infixl" or "infixr";
  2147 
  2148 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2149 sort constraint specifications in type inference; e.g. "x::_::foo"
  2150 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2151 type variable);
  2152 
  2153 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2154 control output of nested => (types); the default behavior is
  2155 "type_brackets";
  2156 
  2157 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2158 tokens into AST constants;
  2159 
  2160 * Pure/syntax: prefer later declarations of translations and print
  2161 translation functions; potential INCOMPATIBILITY: need to reverse
  2162 multiple declarations for same syntax element constant;
  2163 
  2164 * Pure/show_hyps reset by default (in accordance to existing Isar
  2165 practice);
  2166 
  2167 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2168 addSafter;
  2169 
  2170 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2171 as well;
  2172 
  2173 * system: tested support for MacOS X; should be able to get Isabelle +
  2174 Proof General to work in a plain Terminal after installing Poly/ML
  2175 (e.g. from the Isabelle distribution area) and GNU bash alone
  2176 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2177 support requires further installations, e.g. from
  2178 http://fink.sourceforge.net/);
  2179 
  2180 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2181 
  2182 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2183 of 40 MB), cf. ML_OPTIONS;
  2184 
  2185 * system: Proof General keywords specification is now part of the
  2186 Isabelle distribution (see etc/isar-keywords.el);
  2187 
  2188 * system: support for persistent Proof General sessions (refrain from
  2189 outdating all loaded theories on startup); user may create writable
  2190 logic images like this: ``isabelle -q HOL Test'';
  2191 
  2192 * system: smart selection of Isabelle process versus Isabelle
  2193 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2194 run both "isabelle" and "Isabelle" even if file names are badly
  2195 damaged (executable inspects the case of the first letter of its own
  2196 name); added separate "isabelle-process" and "isabelle-interface";
  2197 
  2198 * system: refrain from any attempt at filtering input streams; no
  2199 longer support ``8bit'' encoding of old isabelle font, instead proper
  2200 iso-latin characters may now be used; the related isatools
  2201 "symbolinput" and "nonascii" have disappeared as well;
  2202 
  2203 * system: removed old "xterm" interface (the print modes "xterm" and
  2204 "xterm_color" are still available for direct use in a suitable
  2205 terminal);
  2206 
  2207 
  2208 
  2209 New in Isabelle99-2 (February 2001)
  2210 -----------------------------------
  2211 
  2212 *** Overview of INCOMPATIBILITIES ***
  2213 
  2214 * HOL: please note that theories in the Library and elsewhere often use the
  2215 new-style (Isar) format; to refer to their theorems in an ML script you must
  2216 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2217 
  2218 * HOL: inductive package no longer splits induction rule aggressively,
  2219 but only as far as specified by the introductions given; the old
  2220 format may be recovered via ML function complete_split_rule or attribute
  2221 'split_rule (complete)';
  2222 
  2223 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2224 gfp_Tarski to gfp_unfold;
  2225 
  2226 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2227 
  2228 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2229 relation); infix "^^" has been renamed "``"; infix "``" has been
  2230 renamed "`"; "univalent" has been renamed "single_valued";
  2231 
  2232 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2233 operation;
  2234 
  2235 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2236 
  2237 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2238 
  2239 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2240 consequence, it is no longer monotonic wrt. the local goal context
  2241 (which is now passed through the inductive cases);
  2242 
  2243 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2244 \<gg> to \<ggreater>;
  2245 
  2246 
  2247 *** Document preparation ***
  2248 
  2249 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2250 available: are "it" for near math-mode best-style output, "sl" for
  2251 slanted text style, and "tt" for plain type-writer; if no
  2252 \isabellestyle command is given, output is according to slanted
  2253 type-writer);
  2254 
  2255 * support sub/super scripts (for single symbols only), input syntax is
  2256 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2257 
  2258 * some more standard symbols; see Appendix A of the system manual for
  2259 the complete list of symbols defined in isabellesym.sty;
  2260 
  2261 * improved isabelle style files; more abstract symbol implementation
  2262 (should now use \isamath{...} and \isatext{...} in custom symbol
  2263 definitions);
  2264 
  2265 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2266 state; Note that presentation of goal states does not conform to
  2267 actual human-readable proof documents.  Please do not include goal
  2268 states into document output unless you really know what you are doing!
  2269 
  2270 * proper indentation of antiquoted output with proportional LaTeX
  2271 fonts;
  2272 
  2273 * no_document ML operator temporarily disables LaTeX document
  2274 generation;
  2275 
  2276 * isatool unsymbolize tunes sources for plain ASCII communication;
  2277 
  2278 
  2279 *** Isar ***
  2280 
  2281 * Pure: Isar now suffers initial goal statements to contain unbound
  2282 schematic variables (this does not conform to actual readable proof
  2283 documents, due to unpredictable outcome and non-compositional proof
  2284 checking); users who know what they are doing may use schematic goals
  2285 for Prolog-style synthesis of proven results;
  2286 
  2287 * Pure: assumption method (an implicit finishing) now handles actual
  2288 rules as well;
  2289 
  2290 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2291 initial goal, declare "that" only as Pure intro (only for single
  2292 steps); the "that" rule assumption may now be involved in implicit
  2293 finishing, thus ".." becomes a feasible for trivial obtains;
  2294 
  2295 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2296 instance proofs may be performed by "..";
  2297 
  2298 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2299 statements as well;
  2300 
  2301 * Pure: more robust selection of calculational rules;
  2302 
  2303 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2304 rule (as well as the assumption rule);
  2305 
  2306 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2307 lemmas, using the graph browser tool;
  2308 
  2309 * Pure: predict failure of "show" in interactive mode;
  2310 
  2311 * Pure: 'thms_containing' now takes actual terms as arguments;
  2312 
  2313 * HOL: improved method 'induct' --- now handles non-atomic goals
  2314 (potential INCOMPATIBILITY); tuned error handling;
  2315 
  2316 * HOL: cases and induct rules now provide explicit hints about the
  2317 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2318 any remaining facts are inserted into the goal verbatim;
  2319 
  2320 * HOL: local contexts (aka cases) may now contain term bindings as
  2321 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2322 the result to be shown in each case;
  2323 
  2324 * HOL: added 'recdef_tc' command;
  2325 
  2326 * isatool convert assists in eliminating legacy ML scripts;
  2327 
  2328 
  2329 *** HOL ***
  2330 
  2331 * HOL/Library: a collection of generic theories to be used together
  2332 with main HOL; the theory loader path already includes this directory
  2333 by default; the following existing theories have been moved here:
  2334 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2335 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2336 
  2337 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2338 modelling and verification task performed in Isabelle/HOL +
  2339 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2340 
  2341 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2342 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2343 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2344 'domain', this makes the theory consistent with mathematical
  2345 literature;
  2346 
  2347 * HOL basics: added overloaded operations "inverse" and "divide"
  2348 (infix "/"), syntax for generic "abs" operation, generic summation
  2349 operator \<Sum>;
  2350 
  2351 * HOL/typedef: simplified package, provide more useful rules (see also
  2352 HOL/subset.thy);
  2353 
  2354 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2355 now expressed as a proper nested rule (old-style tactic scripts may
  2356 require atomize_strip_tac to cope with non-atomic premises);
  2357 
  2358 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2359 to "split_conv" (old name still available for compatibility);
  2360 
  2361 * HOL: improved concrete syntax for strings (e.g. allows translation
  2362 rules with string literals);
  2363 
  2364 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2365  and Fleuriot's mechanization of analysis, including the transcendental
  2366  functions for the reals;
  2367 
  2368 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2369 
  2370 
  2371 *** CTT ***
  2372 
  2373 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2374 "lam" is displayed as TWO lambda-symbols
  2375 
  2376 * CTT: theory Main now available, containing everything (that is, Bool
  2377 and Arith);
  2378 
  2379 
  2380 *** General ***
  2381 
  2382 * Pure: the Simplifier has been implemented properly as a derived rule
  2383 outside of the actual kernel (at last!); the overall performance
  2384 penalty in practical applications is about 50%, while reliability of
  2385 the Isabelle inference kernel has been greatly improved;
  2386 
  2387 * print modes "brackets" and "no_brackets" control output of nested =>
  2388 (types) and ==> (props); the default behaviour is "brackets";
  2389 
  2390 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2391 as assumptions as well;
  2392 
  2393 * system: support Poly/ML 4.0;
  2394 
  2395 * system: isatool install handles KDE version 1 or 2;
  2396 
  2397 
  2398 
  2399 New in Isabelle99-1 (October 2000)
  2400 ----------------------------------
  2401 
  2402 *** Overview of INCOMPATIBILITIES ***
  2403 
  2404 * HOL: simplification of natural numbers is much changed; to partly
  2405 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2406 issue the following ML commands:
  2407 
  2408   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2409   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2410 
  2411 * HOL: simplification no longer dives into case-expressions; this is
  2412 controlled by "t.weak_case_cong" for each datatype t;
  2413 
  2414 * HOL: nat_less_induct renamed to less_induct;
  2415 
  2416 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2417 fixsome to patch .thy and .ML sources automatically;
  2418 
  2419   select_equality  -> some_equality
  2420   select_eq_Ex     -> some_eq_ex
  2421   selectI2EX       -> someI2_ex
  2422   selectI2         -> someI2
  2423   selectI          -> someI
  2424   select1_equality -> some1_equality
  2425   Eps_sym_eq       -> some_sym_eq_trivial
  2426   Eps_eq           -> some_eq_trivial
  2427 
  2428 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2429 
  2430 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2431 instead);
  2432 
  2433 * HOL: the recursion equations generated by 'recdef' are now called
  2434 f.simps instead of f.rules;
  2435 
  2436 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2437 
  2438 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2439 sometimes be needed;
  2440 
  2441 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2442 
  2443 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2444 
  2445 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2446 product is now "<*>" instead of "Times"; the lexicographic product is
  2447 now "<*lex*>" instead of "**";
  2448 
  2449 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2450 of main HOL, but was unused); better use HOL's datatype package;
  2451 
  2452 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2453 the old syntax may be recovered as follows:
  2454 
  2455   syntax (symbols)
  2456     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2457       (infixl "\\<oplus>" 100)
  2458 
  2459 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2460 
  2461 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2462 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2463 internally;
  2464 
  2465 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2466 changed from A/r to A//r;
  2467 
  2468 * ZF: new treatment of arithmetic (nat & int) may break some old
  2469 proofs;
  2470 
  2471 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2472 rulify -> rule_format, elimify -> elim_format, ...);
  2473 
  2474 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2475 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2476 should have to change intro!! to intro? only); replaced "delrule" by
  2477 "rule del";
  2478 
  2479 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2480 
  2481 * Provers: strengthened force_tac by using new first_best_tac;
  2482 
  2483 * LaTeX document preparation: several changes of isabelle.sty (see
  2484 lib/texinputs);
  2485 
  2486 
  2487 *** Document preparation ***
  2488 
  2489 * formal comments (text blocks etc.) in new-style theories may now
  2490 contain antiquotations of thm/prop/term/typ/text to be presented
  2491 according to latex print mode; concrete syntax is like this:
  2492 @{term[show_types] "f(x) = a + x"};
  2493 
  2494 * isatool mkdir provides easy setup of Isabelle session directories,
  2495 including proper document sources;
  2496 
  2497 * generated LaTeX sources are now deleted after successful run
  2498 (isatool document -c); may retain a copy somewhere else via -D option
  2499 of isatool usedir;
  2500 
  2501 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2502 style files, achieving self-contained LaTeX sources and simplifying
  2503 LaTeX debugging;
  2504 
  2505 * old-style theories now produce (crude) LaTeX output as well;
  2506 
  2507 * browser info session directories are now self-contained (may be put
  2508 on WWW server seperately); improved graphs of nested sessions; removed
  2509 graph for 'all sessions';
  2510 
  2511 * several improvements in isabelle style files; \isabellestyle{it}
  2512 produces fake math mode output; \isamarkupheader is now \section by
  2513 default; see lib/texinputs/isabelle.sty etc.;
  2514 
  2515 
  2516 *** Isar ***
  2517 
  2518 * Isar/Pure: local results and corresponding term bindings are now
  2519 subject to Hindley-Milner polymorphism (similar to ML); this
  2520 accommodates incremental type-inference very nicely;
  2521 
  2522 * Isar/Pure: new derived language element 'obtain' supports
  2523 generalized existence reasoning;
  2524 
  2525 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2526 support accumulation of results, without applying any rules yet;
  2527 useful to collect intermediate results without explicit name
  2528 references, and for use with transitivity rules with more than 2
  2529 premises;
  2530 
  2531 * Isar/Pure: scalable support for case-analysis type proofs: new
  2532 'case' language element refers to local contexts symbolically, as
  2533 produced by certain proof methods; internally, case names are attached
  2534 to theorems as "tags";
  2535 
  2536 * Isar/Pure: theory command 'hide' removes declarations from
  2537 class/type/const name spaces;
  2538 
  2539 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2540 indicate potential overloading;
  2541 
  2542 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2543 
  2544 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2545 "{a,b,c}" instead of {a,b,c};
  2546 
  2547 * Isar/Pure now provides its own version of intro/elim/dest
  2548 attributes; useful for building new logics, but beware of confusion
  2549 with the version in Provers/classical;
  2550 
  2551 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2552 case name 'antecedent';
  2553 
  2554 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2555 to the current context is now done automatically);
  2556 
  2557 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2558 for definining proof methods in ML;
  2559 
  2560 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2561 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2562 most cases, one should have to change intro!! to intro? only);
  2563 replaced "delrule" by "rule del";
  2564 
  2565 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2566 'symmetric' attribute (the latter supercedes [RS sym]);
  2567 
  2568 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2569 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2570 well (including splits);
  2571 
  2572 * Isar/Provers: Simplifier and Classical methods now support all kind
  2573 of modifiers used in the past, including 'cong', 'iff', etc.
  2574 
  2575 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2576 of Simplifier and Classical reasoner);
  2577 
  2578 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2579 now support named cases; major packages (inductive, datatype, primrec,
  2580 recdef) support case names and properly name parameters;
  2581 
  2582 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2583 monotonicity conditions are extracted to be proven at end of
  2584 calculations;
  2585 
  2586 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2587 method anyway;
  2588 
  2589 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2590 split_if split_if_asm; datatype package provides theorems foo.splits =
  2591 foo.split foo.split_asm for each datatype;
  2592 
  2593 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2594 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2595 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2596 use "(cases (simplified))" method in proper proof texts);
  2597 
  2598 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2599 
  2600 * Isar: names of theorems etc. may be natural numbers as well;
  2601 
  2602 * Isar: 'pr' command: optional arguments for goals_limit and
  2603 ProofContext.prems_limit; no longer prints theory contexts, but only
  2604 proof states;
  2605 
  2606 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2607 additional print modes to be specified; e.g. "pr(latex)" will print
  2608 proof state according to the Isabelle LaTeX style;
  2609 
  2610 * Isar: improved support for emulating tactic scripts, including proof
  2611 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2612 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2613 (for HOL datatypes);
  2614 
  2615 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2616 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2617 'proof method scripts' have to be in depth-first order;
  2618 
  2619 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2620 
  2621 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2622 should instead use individual commands for printing items
  2623 (print_commands, print_methods etc.);
  2624 
  2625 * Isar: added 'nothing' --- the empty list of theorems;
  2626 
  2627 
  2628 *** HOL ***
  2629 
  2630 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2631 corresponding virtual machine and a specification of its bytecode
  2632 verifier and a lightweight bytecode verifier, including proofs of
  2633 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2634 Cornelia Pusch (see also the homepage of project Bali at
  2635 http://isabelle.in.tum.de/Bali/);
  2636 
  2637 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2638 Clemens Ballarin;
  2639 
  2640 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2641 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2642 Rasmussen;
  2643 
  2644 * HOL/Lattice: fundamental concepts of lattice theory and order
  2645 structures, including duals, properties of bounds versus algebraic
  2646 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2647 Theorem for complete lattices etc.; may also serve as a demonstration
  2648 for abstract algebraic reasoning using axiomatic type classes, and
  2649 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2650 
  2651 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2652 von Oheimb;
  2653 
  2654 * HOL/IMPP: extension of IMP with local variables and mutually
  2655 recursive procedures, by David von Oheimb;
  2656 
  2657 * HOL/Lambda: converted into new-style theory and document;
  2658 
  2659 * HOL/ex/Multiquote: example of multiple nested quotations and
  2660 anti-quotations -- basically a generalized version of de-Bruijn
  2661 representation; very useful in avoiding lifting of operations;
  2662 
  2663 * HOL/record: added general record equality rule to simpset; fixed
  2664 select-update simplification procedure to handle extended records as
  2665 well; admit "r" as field name;
  2666 
  2667 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2668 other numeric types and also as the identity of groups, rings, etc.;
  2669 
  2670 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2671 Types nat and int belong to this axclass;
  2672 
  2673 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2674    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2675    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2676   two terms #m*u and #n*u are replaced by #(m+n)*u
  2677     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2678   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2679     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2680 
  2681 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2682 powerful prover for predicate logic but knows nothing of clasets; see
  2683 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2684 
  2685 * HOL: new version of "case_tac" subsumes both boolean case split and
  2686 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2687 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2688 
  2689 * HOL: simplification no longer dives into case-expressions: only the
  2690 selector expression is simplified, but not the remaining arms; to
  2691 enable full simplification of case-expressions for datatype t, you may
  2692 remove t.weak_case_cong from the simpset, either globally (Delcongs
  2693 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  2694 
  2695 * HOL/recdef: the recursion equations generated by 'recdef' for
  2696 function 'f' are now called f.simps instead of f.rules; if all
  2697 termination conditions are proved automatically, these simplification
  2698 rules are added to the simpset, as in primrec; rules may be named
  2699 individually as well, resulting in a separate list of theorems for
  2700 each equation;
  2701 
  2702 * HOL/While is a new theory that provides a while-combinator. It
  2703 permits the definition of tail-recursive functions without the
  2704 provision of a termination measure. The latter is necessary once the
  2705 invariant proof rule for while is applied.
  2706 
  2707 * HOL: new (overloaded) notation for the set of elements below/above
  2708 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  2709 
  2710 * HOL: theorems impI, allI, ballI bound as "strip";
  2711 
  2712 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2713 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2714 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2715 
  2716 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2717 
  2718 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2719 main HOL, but was unused);
  2720 
  2721 * HOL: fewer consts declared as global (e.g. have to refer to
  2722 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2723 
  2724 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2725 in case of overlap with user translations (e.g. judgements over
  2726 tuples); (note that the underlying logical represenation is still
  2727 bogus);
  2728 
  2729 
  2730 *** ZF ***
  2731 
  2732 * ZF: simplification automatically cancels common terms in arithmetic
  2733 expressions over nat and int;
  2734 
  2735 * ZF: new treatment of nat to minimize type-checking: all operators
  2736 coerce their operands to a natural number using the function natify,
  2737 making the algebraic laws unconditional;
  2738 
  2739 * ZF: as above, for int: operators coerce their operands to an integer
  2740 using the function intify;
  2741 
  2742 * ZF: the integer library now contains many of the usual laws for the
  2743 orderings, including $<=, and monotonicity laws for $+ and $*;
  2744 
  2745 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  2746 simplification;
  2747 
  2748 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  2749 to the simplifier and classical reasoner simultaneously;
  2750 
  2751 
  2752 *** General ***
  2753 
  2754 * Provers: blast_tac now handles actual object-logic rules as
  2755 assumptions; note that auto_tac uses blast_tac internally as well;
  2756 
  2757 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  2758 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  2759 
  2760 * Provers: delrules now handles destruct rules as well (no longer need
  2761 explicit make_elim);
  2762 
  2763 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  2764   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2765 use instead the strong form,
  2766   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2767 in HOL, FOL and ZF the function cla_make_elim will create such rules
  2768 from destruct-rules;
  2769 
  2770 * Provers: Simplifier.easy_setup provides a fast path to basic
  2771 Simplifier setup for new object-logics;
  2772 
  2773 * Pure: AST translation rules no longer require constant head on LHS;
  2774 
  2775 * Pure: improved name spaces: ambiguous output is qualified; support
  2776 for hiding of names;
  2777 
  2778 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  2779 XSYMBOL_HOME; no longer need to do manual configuration in most
  2780 situations;
  2781 
  2782 * system: compression of ML heaps images may now be controlled via -c
  2783 option of isabelle and isatool usedir (currently only observed by
  2784 Poly/ML);
  2785 
  2786 * system: isatool installfonts may handle X-Symbol fonts as well (very
  2787 useful for remote X11);
  2788 
  2789 * system: provide TAGS file for Isabelle sources;
  2790 
  2791 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  2792 order;
  2793 
  2794 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  2795 timing flag supersedes proof_timing and Toplevel.trace;
  2796 
  2797 * ML: new combinators |>> and |>>> for incremental transformations
  2798 with secondary results (e.g. certain theory extensions):
  2799 
  2800 * ML: PureThy.add_defs gets additional argument to indicate potential
  2801 overloading (usually false);
  2802 
  2803 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  2804 results;
  2805 
  2806 
  2807 
  2808 New in Isabelle99 (October 1999)
  2809 --------------------------------
  2810 
  2811 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2812 
  2813 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  2814 are no longer simplified.  (This allows the simplifier to unfold recursive
  2815 functional programs.)  To restore the old behaviour, declare
  2816 
  2817     Delcongs [if_weak_cong];
  2818 
  2819 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2820 complement;
  2821 
  2822 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2823 
  2824 * HOL/datatype: mutual_induct_tac no longer exists --
  2825   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2826 
  2827 * HOL/typedef: fixed type inference for representing set; type
  2828 arguments now have to occur explicitly on the rhs as type constraints;
  2829 
  2830 * ZF: The con_defs part of an inductive definition may no longer refer
  2831 to constants declared in the same theory;
  2832 
  2833 * HOL, ZF: the function mk_cases, generated by the inductive
  2834 definition package, has lost an argument.  To simplify its result, it
  2835 uses the default simpset instead of a supplied list of theorems.
  2836 
  2837 * HOL/List: the constructors of type list are now Nil and Cons;
  2838 
  2839 * Simplifier: the type of the infix ML functions
  2840         setSSolver addSSolver setSolver addSolver
  2841 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2842 for packaging solvers. A solver is created via
  2843         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2844 where the string argument is only a comment.
  2845 
  2846 
  2847 *** Proof tools ***
  2848 
  2849 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2850 decision procedure for linear arithmetic. Currently it is used for
  2851 types `nat', `int', and `real' in HOL (see below); it can, should and
  2852 will be instantiated for other types and logics as well.
  2853 
  2854 * The simplifier now accepts rewrite rules with flexible heads, eg
  2855      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2856   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2857   matching.
  2858 
  2859 
  2860 *** General ***
  2861 
  2862 * New Isabelle/Isar subsystem provides an alternative to traditional
  2863 tactical theorem proving; together with the ProofGeneral/isar user
  2864 interface it offers an interactive environment for developing human
  2865 readable proof documents (Isar == Intelligible semi-automated
  2866 reasoning); for further information see isatool doc isar-ref,
  2867 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2868 
  2869 * improved and simplified presentation of theories: better HTML markup
  2870 (including colors), graph views in several sizes; isatool usedir now
  2871 provides a proper interface for user theories (via -P option); actual
  2872 document preparation based on (PDF)LaTeX is available as well (for
  2873 new-style theories only); see isatool doc system for more information;
  2874 
  2875 * native support for Proof General, both for classic Isabelle and
  2876 Isabelle/Isar;
  2877 
  2878 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2879 using the graph browser tool;
  2880 
  2881 * Isabelle manuals now also available as PDF;
  2882 
  2883 * theory loader rewritten from scratch (may not be fully
  2884 bug-compatible); old loadpath variable has been replaced by show_path,
  2885 add_path, del_path, reset_path functions; new operations such as
  2886 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2887 isatool doc ref);
  2888 
  2889 * improved isatool install: option -k creates KDE application icon,
  2890 option -p DIR installs standalone binaries;
  2891 
  2892 * added ML_PLATFORM setting (useful for cross-platform installations);
  2893 more robust handling of platform specific ML images for SML/NJ;
  2894 
  2895 * the settings environment is now statically scoped, i.e. it is never
  2896 created again in sub-processes invoked from isabelle, isatool, or
  2897 Isabelle;
  2898 
  2899 * path element specification '~~' refers to '$ISABELLE_HOME';
  2900 
  2901 * in locales, the "assumes" and "defines" parts may be omitted if
  2902 empty;
  2903 
  2904 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2905 long arrows);
  2906 
  2907 * new print_mode "HTML";
  2908 
  2909 * new flag show_tags controls display of tags of theorems (which are
  2910 basically just comments that may be attached by some tools);
  2911 
  2912 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2913 mode and goal output format:
  2914 
  2915 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2916 244c244
  2917 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2918 ---
  2919 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2920 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2921 181c181
  2922 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2923 ---
  2924 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2925 
  2926 * function bind_thms stores lists of theorems (cf. bind_thm);
  2927 
  2928 * new shorthand tactics ftac, eatac, datac, fatac;
  2929 
  2930 * qed (and friends) now accept "" as result name; in that case the
  2931 theorem is not stored, but proper checks and presentation of the
  2932 result still apply;
  2933 
  2934 * theorem database now also indexes constants "Trueprop", "all",
  2935 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2936 
  2937 
  2938 *** HOL ***
  2939 
  2940 ** HOL arithmetic **
  2941 
  2942 * There are now decision procedures for linear arithmetic over nat and
  2943 int:
  2944 
  2945 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2946 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2947 are treated as atomic; subformulae not involving type `nat' or `int'
  2948 are ignored; quantified subformulae are ignored unless they are
  2949 positive universal or negative existential. The tactic has to be
  2950 invoked by hand and can be a little bit slow. In particular, the
  2951 running time is exponential in the number of occurrences of `min' and
  2952 `max', and `-' on `nat'.
  2953 
  2954 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2955 (negated) (in)equalities among the premises and the conclusion into
  2956 account (i.e. no compound formulae) and does not know about `min' and
  2957 `max', and `-' on `nat'. It is fast and is used automatically by the
  2958 simplifier.
  2959 
  2960 NB: At the moment, these decision procedures do not cope with mixed
  2961 nat/int formulae where the two parts interact, such as `m < n ==>
  2962 int(m) < int(n)'.
  2963 
  2964 * HOL/Numeral provides a generic theory of numerals (encoded
  2965 efficiently as bit strings); setup for types nat/int/real is in place;
  2966 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2967 int, existing theories and proof scripts may require a few additional
  2968 type constraints;
  2969 
  2970 * integer division and remainder can now be performed on constant
  2971 arguments;
  2972 
  2973 * many properties of integer multiplication, division and remainder
  2974 are now available;
  2975 
  2976 * An interface to the Stanford Validity Checker (SVC) is available through the
  2977 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2978 are proved automatically.  SVC must be installed separately, and its results
  2979 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2980 invocation of the underlying oracle).  For SVC see
  2981   http://verify.stanford.edu/SVC
  2982 
  2983 * IsaMakefile: the HOL-Real target now builds an actual image;
  2984 
  2985 
  2986 ** HOL misc **
  2987 
  2988 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2989 (in Isabelle/Isar) -- by Gertrud Bauer;
  2990 
  2991 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2992 analysis for assembly languages with subtypes;
  2993 
  2994 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2995 -- avoids syntactic ambiguities and treats state, transition, and
  2996 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2997 changed syntax and (many) tactics;
  2998 
  2999 * HOL/inductive: Now also handles more general introduction rules such
  3000   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  3001   theorems are now maintained within the theory (maintained via the
  3002   "mono" attribute);
  3003 
  3004 * HOL/datatype: Now also handles arbitrarily branching datatypes
  3005   (using function types) such as
  3006 
  3007   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  3008 
  3009 * HOL/record: record_simproc (part of the default simpset) takes care
  3010 of selectors applied to updated records; record_split_tac is no longer
  3011 part of the default claset; update_defs may now be removed from the
  3012 simpset in many cases; COMPATIBILITY: old behavior achieved by
  3013 
  3014   claset_ref () := claset() addSWrapper record_split_wrapper;
  3015   Delsimprocs [record_simproc]
  3016 
  3017 * HOL/typedef: fixed type inference for representing set; type
  3018 arguments now have to occur explicitly on the rhs as type constraints;
  3019 
  3020 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  3021 names rather than an ML expression;
  3022 
  3023 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  3024 supplied later.  Program schemes can be defined, such as
  3025     "While B C s = (if B s then While B C (C s) else s)"
  3026 where the well-founded relation can be chosen after B and C have been given.
  3027 
  3028 * HOL/List: the constructors of type list are now Nil and Cons;
  3029 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  3030 course, ML tools referring to List.list.op # etc. have to be adapted;
  3031 
  3032 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  3033 disabled by default; run isabelle with option -m HOL to get back to
  3034 the original Gordon/HOL-style output;
  3035 
  3036 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  3037 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  3038 
  3039 * HOL basic syntax simplified (more orthogonal): all variants of
  3040 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  3041 Eps operator is provided as well: "SOME x. P[x]";
  3042 
  3043 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  3044 
  3045 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  3046 thus available for user theories;
  3047 
  3048 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  3049 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  3050 time;
  3051 
  3052 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  3053 several times and then mp;
  3054 
  3055 
  3056 *** LK ***
  3057 
  3058 * the notation <<...>> is now available as a notation for sequences of
  3059 formulas;
  3060 
  3061 * the simplifier is now installed
  3062 
  3063 * the axiom system has been generalized (thanks to Soren Heilmann)
  3064 
  3065 * the classical reasoner now has a default rule database
  3066 
  3067 
  3068 *** ZF ***
  3069 
  3070 * new primrec section allows primitive recursive functions to be given
  3071 directly (as in HOL) over datatypes and the natural numbers;
  3072 
  3073 * new tactics induct_tac and exhaust_tac for induction (or case
  3074 analysis) over datatypes and the natural numbers;
  3075 
  3076 * the datatype declaration of type T now defines the recursor T_rec;
  3077 
  3078 * simplification automatically does freeness reasoning for datatype
  3079 constructors;
  3080 
  3081 * automatic type-inference, with AddTCs command to insert new
  3082 type-checking rules;
  3083 
  3084 * datatype introduction rules are now added as Safe Introduction rules
  3085 to the claset;
  3086 
  3087 * the syntax "if P then x else y" is now available in addition to
  3088 if(P,x,y);
  3089 
  3090 
  3091 *** Internal programming interfaces ***
  3092 
  3093 * tuned simplifier trace output; new flag debug_simp;
  3094 
  3095 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3096 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3097 
  3098 * AxClass.axclass_tac lost the theory argument;
  3099 
  3100 * tuned current_goals_markers semantics: begin / end goal avoids
  3101 printing empty lines;
  3102 
  3103 * removed prs and prs_fn hook, which was broken because it did not
  3104 include \n in its semantics, forcing writeln to add one
  3105 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3106 string -> unit if you really want to output text without newline;
  3107 
  3108 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3109 plain output, interface builders may have to enable 'isabelle_font'
  3110 mode to get Isabelle font glyphs as before;
  3111 
  3112 * refined token_translation interface; INCOMPATIBILITY: output length
  3113 now of type real instead of int;
  3114 
  3115 * theory loader actions may be traced via new ThyInfo.add_hook
  3116 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3117 your own database of information attached to *whole* theories -- as
  3118 opposed to intra-theory data slots offered via TheoryDataFun;
  3119 
  3120 * proper handling of dangling sort hypotheses (at last!);
  3121 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3122 extra sort hypotheses that can be witnessed from the type signature;
  3123 the force_strip_shyps flag is gone, any remaining shyps are simply
  3124 left in the theorem (with a warning issued by strip_shyps_warning);
  3125 
  3126 
  3127 
  3128 New in Isabelle98-1 (October 1998)
  3129 ----------------------------------
  3130 
  3131 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3132 
  3133 * several changes of automated proof tools;
  3134 
  3135 * HOL: major changes to the inductive and datatype packages, including
  3136 some minor incompatibilities of theory syntax;
  3137 
  3138 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3139 called `inj_on';
  3140 
  3141 * HOL: removed duplicate thms in Arith:
  3142   less_imp_add_less  should be replaced by  trans_less_add1
  3143   le_imp_add_le      should be replaced by  trans_le_add1
  3144 
  3145 * HOL: unary minus is now overloaded (new type constraints may be
  3146 required);
  3147 
  3148 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3149 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3150 now taken as an integer constant.
  3151 
  3152 * Pure: ML function 'theory_of' renamed to 'theory';
  3153 
  3154 
  3155 *** Proof tools ***
  3156 
  3157 * Simplifier:
  3158   1. Asm_full_simp_tac is now more aggressive.
  3159      1. It will sometimes reorient premises if that increases their power to
  3160         simplify.
  3161      2. It does no longer proceed strictly from left to right but may also
  3162         rotate premises to achieve further simplification.
  3163      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3164      old Asm_full_simp_tac in that it does not rotate premises.
  3165   2. The simplifier now knows a little bit about nat-arithmetic.
  3166 
  3167 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3168 allows for selected deletion of wrappers, by introduction of names for
  3169 wrapper functionals.  This implies that addbefore, addSbefore,
  3170 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3171 and that adding two tactics with the same name overwrites the first
  3172 one (emitting a warning).
  3173   type wrapper = (int -> tactic) -> (int -> tactic)
  3174   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3175   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3176   delWrapper, delSWrapper: claset *  string            -> claset
  3177   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3178 
  3179 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3180 semantics; addbefore now affects only the unsafe part of step_tac
  3181 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3182 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3183 by Force_tac;
  3184 
  3185 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3186 compWrapper; added safe wrapper (and access functions for it);
  3187 
  3188 * HOL/split_all_tac is now much faster and fails if there is nothing
  3189 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3190 and the names of the automatically generated variables have changed.
  3191 split_all_tac has moved within claset() from unsafe wrappers to safe
  3192 wrappers, which means that !!-bound variables are split much more
  3193 aggressively, and safe_tac and clarify_tac now split such variables.
  3194 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3195 Note: the same holds for record_split_tac, which does the job of
  3196 split_all_tac for record fields.
  3197 
  3198 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3199 permanently to the default simpset using Addsplits just like
  3200 Addsimps. They can be removed via Delsplits just like
  3201 Delsimps. Lower-case versions are also available.
  3202 
  3203 * HOL/Simplifier: The rule split_if is now part of the default
  3204 simpset. This means that the simplifier will eliminate all occurrences
  3205 of if-then-else in the conclusion of a goal. To prevent this, you can
  3206 either remove split_if completely from the default simpset by
  3207 `Delsplits [split_if]' or remove it in a specific call of the
  3208 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3209 other case splitting rules to/from the default simpset: every datatype
  3210 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3211 t is the name of the datatype).
  3212 
  3213 * Classical reasoner / Simplifier combination: new force_tac (and
  3214 derivatives Force_tac, force) combines rewriting and classical
  3215 reasoning (and whatever other tools) similarly to auto_tac, but is
  3216 aimed to solve the given subgoal completely.
  3217 
  3218 
  3219 *** General ***
  3220 
  3221 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3222 and `goalw': the theory is no longer needed as an explicit argument -
  3223 the current theory context is used; assumptions are no longer returned
  3224 at the ML-level unless one of them starts with ==> or !!; it is
  3225 recommended to convert to these new commands using isatool fixgoal
  3226 (backup your sources first!);
  3227 
  3228 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3229 the current theory context, and 'theory' to lookup stored theories;
  3230 
  3231 * new theory section 'locale' for declaring constants, assumptions and
  3232 definitions that have local scope;
  3233 
  3234 * new theory section 'nonterminals' for purely syntactic types;
  3235 
  3236 * new theory section 'setup' for generic ML setup functions
  3237 (e.g. package initialization);
  3238 
  3239 * the distribution now includes Isabelle icons: see
  3240 lib/logo/isabelle-{small,tiny}.xpm;
  3241 
  3242 * isatool install - install binaries with absolute references to
  3243 ISABELLE_HOME/bin;
  3244 
  3245 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3246 
  3247 * print mode 'emacs' reserved for Isamode;
  3248 
  3249 * support multiple print (ast) translations per constant name;
  3250 
  3251 * theorems involving oracles are now printed with a suffixed [!];
  3252 
  3253 
  3254 *** HOL ***
  3255 
  3256 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3257 
  3258 * HOL/inductive package reorganized and improved: now supports mutual
  3259 definitions such as
  3260 
  3261   inductive EVEN ODD
  3262     intrs
  3263       null "0 : EVEN"
  3264       oddI "n : EVEN ==> Suc n : ODD"
  3265       evenI "n : ODD ==> Suc n : EVEN"
  3266 
  3267 new theorem list "elims" contains an elimination rule for each of the
  3268 recursive sets; inductive definitions now handle disjunctive premises
  3269 correctly (also ZF);
  3270 
  3271 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3272 "mutual_induct" no longer exists - the induction rule is always
  3273 contained in "induct";
  3274 
  3275 
  3276 * HOL/datatype package re-implemented and greatly improved: now
  3277 supports mutually recursive datatypes such as
  3278 
  3279   datatype
  3280     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3281             | SUM ('a aexp) ('a aexp)
  3282             | DIFF ('a aexp) ('a aexp)
  3283             | NUM 'a
  3284   and
  3285     'a bexp = LESS ('a aexp) ('a aexp)
  3286             | AND ('a bexp) ('a bexp)
  3287             | OR ('a bexp) ('a bexp)
  3288 
  3289 as well as indirectly recursive datatypes such as
  3290 
  3291   datatype
  3292     ('a, 'b) term = Var 'a
  3293                   | App 'b ((('a, 'b) term) list)
  3294 
  3295 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3296 induction on mutually / indirectly recursive datatypes.
  3297 
  3298 Primrec equations are now stored in theory and can be accessed via
  3299 <function_name>.simps.
  3300 
  3301 INCOMPATIBILITIES:
  3302 
  3303   - Theories using datatypes must now have theory Datatype as an
  3304     ancestor.
  3305   - The specific <typename>.induct_tac no longer exists - use the
  3306     generic induct_tac instead.
  3307   - natE has been renamed to nat.exhaust - use exhaust_tac
  3308     instead of res_inst_tac ... natE. Note that the variable
  3309     names in nat.exhaust differ from the names in natE, this
  3310     may cause some "fragile" proofs to fail.
  3311   - The theorems split_<typename>_case and split_<typename>_case_asm
  3312     have been renamed to <typename>.split and <typename>.split_asm.
  3313   - Since default sorts of type variables are now handled correctly,
  3314     some datatype definitions may have to be annotated with explicit
  3315     sort constraints.
  3316   - Primrec definitions no longer require function name and type
  3317     of recursive argument.
  3318 
  3319 Consider using isatool fixdatatype to adapt your theories and proof
  3320 scripts to the new package (backup your sources first!).
  3321 
  3322 
  3323 * HOL/record package: considerably improved implementation; now
  3324 includes concrete syntax for record types, terms, updates; theorems
  3325 for surjective pairing and splitting !!-bound record variables; proof
  3326 support is as follows:
  3327 
  3328   1) standard conversions (selectors or updates applied to record
  3329 constructor terms) are part of the standard simpset;
  3330 
  3331   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3332 made part of standard simpset and claset via addIffs;
  3333 
  3334   3) a tactic for record field splitting (record_split_tac) is part of
  3335 the standard claset (addSWrapper);
  3336 
  3337 To get a better idea about these rules you may retrieve them via
  3338 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3339 the name of your record type.
  3340 
  3341 The split tactic 3) conceptually simplifies by the following rule:
  3342 
  3343   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3344 
  3345 Thus any record variable that is bound by meta-all will automatically
  3346 blow up into some record constructor term, consequently the
  3347 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3348 solve record problems automatically.
  3349 
  3350 
  3351 * reorganized the main HOL image: HOL/Integ and String loaded by
  3352 default; theory Main includes everything;
  3353 
  3354 * automatic simplification of integer sums and comparisons, using cancellation;
  3355 
  3356 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3357 
  3358 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3359 
  3360 * many new identities for unions, intersections, set difference, etc.;
  3361 
  3362 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3363 called split_if, split_split, split_sum_case and split_nat_case (to go
  3364 with add/delsplits);
  3365 
  3366 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3367 (?x::unit) = (); this is made part of the default simpset, which COULD
  3368 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3369 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3370 unit_abs_eta_conv is added in order to counter the effect of
  3371 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3372 %u.f();
  3373 
  3374 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3375 makes more sense);
  3376 
  3377 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3378   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3379   disjointness reasoning but breaking a few old proofs.
  3380 
  3381 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3382 to 'converse' from 'inverse' (for compatibility with ZF and some
  3383 literature);
  3384 
  3385 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3386 the well-founded relation;
  3387 
  3388 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3389     Compl A.  The "Compl" syntax remains available as input syntax for this
  3390     release ONLY.
  3391 
  3392 * HOL/Update: new theory of function updates:
  3393     f(a:=b) == %x. if x=a then b else f x
  3394 may also be iterated as in f(a:=b,c:=d,...);
  3395 
  3396 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3397 
  3398 * HOL/List:
  3399   - new function list_update written xs[i:=v] that updates the i-th
  3400     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3401   - new function `upt' written [i..j(] which generates the list
  3402     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3403     bound write [i..j], which is a shorthand for [i..j+1(].
  3404   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3405 
  3406 * HOL/Arith:
  3407   - removed 'pred' (predecessor) function;
  3408   - generalized some theorems about n-1;
  3409   - many new laws about "div" and "mod";
  3410   - new laws about greatest common divisors (see theory ex/Primes);
  3411 
  3412 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3413 instead of "inverse";
  3414 
  3415 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3416   of the multiset ordering;
  3417 
  3418 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3419   (not included by default);
  3420 
  3421 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3422 
  3423 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3424   programs, i.e. different program variables may have different types.
  3425 
  3426 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3427   [previously, this check worked only if the rewrite rule was unconditional]
  3428   Now rew can involve either definitions or equalities (either == or =).
  3429 
  3430 
  3431 *** ZF ***
  3432 
  3433 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3434   only the theorems proved on ZF.ML;
  3435 
  3436 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3437   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3438   disjointness reasoning but breaking a few old proofs.
  3439 
  3440 * ZF/Update: new theory of function updates
  3441     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3442   may also be iterated as in f(a:=b,c:=d,...);
  3443 
  3444 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3445 
  3446 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3447   [previously, this check worked only if the rewrite rule was unconditional]
  3448   Now rew can involve either definitions or equalities (either == or =).
  3449 
  3450 * case_tac provided for compatibility with HOL
  3451     (like the old excluded_middle_tac, but with subgoals swapped)
  3452 
  3453 
  3454 *** Internal programming interfaces ***
  3455 
  3456 * Pure: several new basic modules made available for general use, see
  3457 also src/Pure/README;
  3458 
  3459 * improved the theory data mechanism to support encapsulation (data
  3460 kind name replaced by private Object.kind, acting as authorization
  3461 key); new type-safe user interface via functor TheoryDataFun; generic
  3462 print_data function becomes basically useless;
  3463 
  3464 * removed global_names compatibility flag -- all theory declarations
  3465 are qualified by default;
  3466 
  3467 * module Pure/Syntax now offers quote / antiquote translation
  3468 functions (useful for Hoare logic etc. with implicit dependencies);
  3469 see HOL/ex/Antiquote for an example use;
  3470 
  3471 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3472 cterm -> thm;
  3473 
  3474 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3475 subgoal;
  3476 
  3477 * Display.print_goals function moved to Locale.print_goals;
  3478 
  3479 * standard print function for goals supports current_goals_markers
  3480 variable for marking begin of proof, end of proof, start of goal; the
  3481 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3482 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3483 for example;
  3484 
  3485 
  3486 
  3487 New in Isabelle98 (January 1998)
  3488 --------------------------------
  3489 
  3490 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3491 
  3492 * changed lexical syntax of terms / types: dots made part of long
  3493 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3494 
  3495 * simpset (and claset) reference variable replaced by functions
  3496 simpset / simpset_ref;
  3497 
  3498 * no longer supports theory aliases (via merge) and non-trivial
  3499 implicit merge of thms' signatures;
  3500 
  3501 * most internal names of constants changed due to qualified names;
  3502 
  3503 * changed Pure/Sequence interface (see Pure/seq.ML);
  3504 
  3505 
  3506 *** General Changes ***
  3507 
  3508 * hierachically structured name spaces (for consts, types, axms, thms
  3509 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3510 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3511 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3512 long_names for fully qualified output names; NOTE: ML programs
  3513 (special tactics, packages etc.) referring to internal names may have
  3514 to be adapted to cope with fully qualified names; in case of severe
  3515 backward campatibility problems try setting 'global_names' at compile
  3516 time to have enrything declared within a flat name space; one may also
  3517 fine tune name declarations in theories via the 'global' and 'local'
  3518 section;
  3519 
  3520 * reimplemented the implicit simpset and claset using the new anytype
  3521 data filed in signatures; references simpset:simpset ref etc. are
  3522 replaced by functions simpset:unit->simpset and
  3523 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3524 to patch your ML files accordingly;
  3525 
  3526 * HTML output now includes theory graph data for display with Java
  3527 applet or isatool browser; data generated automatically via isatool
  3528 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3529 
  3530 * defs may now be conditional; improved rewrite_goals_tac to handle
  3531 conditional equations;
  3532 
  3533 * defs now admits additional type arguments, using TYPE('a) syntax;
  3534 
  3535 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3536 creates a new theory node; implicit merge of thms' signatures is
  3537 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3538 transfer:theory->thm->thm in (rare) cases;
  3539 
  3540 * improved handling of draft signatures / theories; draft thms (and
  3541 ctyps, cterms) are automatically promoted to real ones;
  3542 
  3543 * slightly changed interfaces for oracles: admit many per theory, named
  3544 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3545 
  3546 * print_goals: optional output of const types (set show_consts and
  3547 show_types);
  3548 
  3549 * improved output of warnings (###) and errors (***);
  3550 
  3551 * subgoal_tac displays a warning if the new subgoal has type variables;
  3552 
  3553 * removed old README and Makefiles;
  3554 
  3555 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3556 
  3557 * removed obsolete init_pps and init_database;
  3558 
  3559 * deleted the obsolete tactical STATE, which was declared by
  3560     fun STATE tacfun st = tacfun st st;
  3561 
  3562 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3563 (which abbreviates $HOME);
  3564 
  3565 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3566 use isatool fixseq to adapt your ML programs (this works for fully
  3567 qualified references to the Sequence structure only!);
  3568 
  3569 * use_thy no longer requires writable current directory; it always
  3570 reloads .ML *and* .thy file, if either one is out of date;
  3571 
  3572 
  3573 *** Classical Reasoner ***
  3574 
  3575 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3576 tactics that use classical reasoning to simplify a subgoal without
  3577 splitting it into several subgoals;
  3578 
  3579 * Safe_tac: like safe_tac but uses the default claset;
  3580 
  3581 
  3582 *** Simplifier ***
  3583 
  3584 * added simplification meta rules:
  3585     (asm_)(full_)simplify: simpset -> thm -> thm;
  3586 
  3587 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3588 logics (again);
  3589 
  3590 * added prems argument to simplification procedures;
  3591 
  3592 * HOL, FOL, ZF: added infix function `addsplits':
  3593   instead of `<simpset> setloop (split_tac <thms>)'
  3594   you can simply write `<simpset> addsplits <thms>'
  3595 
  3596 
  3597 *** Syntax ***
  3598 
  3599 * TYPE('a) syntax for type reflection terms;
  3600 
  3601 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3602 
  3603 * pretty printer: changed order of mixfix annotation preference (again!);
  3604 
  3605 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3606 
  3607 
  3608 *** HOL ***
  3609 
  3610 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3611   with `addloop' of the simplifier to faciliate case splitting in premises.
  3612 
  3613 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3614 
  3615 * HOL/Auth: new protocol proofs including some for the Internet
  3616   protocol TLS;
  3617 
  3618 * HOL/Map: new theory of `maps' a la VDM;
  3619 
  3620 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3621 cancelling out common nat summands from =, <, <= (in)equalities, or
  3622 differences; simplification procedures nat_cancel_factor for
  3623 cancelling common factor from =, <, <= (in)equalities over natural
  3624 sums; nat_cancel contains both kinds of procedures, it is installed by
  3625 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3626 
  3627 * HOL/simplifier: terms of the form
  3628   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3629   are rewritten to
  3630   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3631   and those of the form
  3632   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3633   are rewritten to
  3634   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3635 
  3636 * HOL/datatype
  3637   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3638 
  3639   P(t_case f1 ... fn x) =
  3640      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3641         ...
  3642        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3643      )
  3644 
  3645   and a theorem `split_t_case_asm' of the form
  3646 
  3647   P(t_case f1 ... fn x) =
  3648     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3649         ...
  3650        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3651      )
  3652   which can be added to a simpset via `addsplits'. The existing theorems
  3653   expand_list_case and expand_option_case have been renamed to
  3654   split_list_case and split_option_case.
  3655 
  3656 * HOL/Arithmetic:
  3657   - `pred n' is automatically converted to `n-1'.
  3658     Users are strongly encouraged not to use `pred' any longer,
  3659     because it will disappear altogether at some point.
  3660   - Users are strongly encouraged to write "0 < n" rather than
  3661     "n ~= 0". Theorems and proof tools have been modified towards this
  3662     `standard'.
  3663 
  3664 * HOL/Lists:
  3665   the function "set_of_list" has been renamed "set" (and its theorems too);
  3666   the function "nth" now takes its arguments in the reverse order and
  3667   has acquired the infix notation "!" as in "xs!n".
  3668 
  3669 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3670 
  3671 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3672   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3673 
  3674 * HOL/record: extensible records with schematic structural subtyping
  3675 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3676 still lacks various theorems and concrete record syntax;
  3677 
  3678 
  3679 *** HOLCF ***
  3680 
  3681 * removed "axioms" and "generated by" sections;
  3682 
  3683 * replaced "ops" section by extended "consts" section, which is capable of
  3684   handling the continuous function space "->" directly;
  3685 
  3686 * domain package:
  3687   . proves theorems immediately and stores them in the theory,
  3688   . creates hierachical name space,
  3689   . now uses normal mixfix annotations (instead of cinfix...),
  3690   . minor changes to some names and values (for consistency),
  3691   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  3692   . separator between mutual domain defs: changed "," to "and",
  3693   . improved handling of sort constraints;  now they have to
  3694     appear on the left-hand side of the equations only;
  3695 
  3696 * fixed LAM <x,y,zs>.b syntax;
  3697 
  3698 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  3699 adm (%x. P (t x)), where P is chainfinite and t continuous;
  3700 
  3701 
  3702 *** FOL and ZF ***
  3703 
  3704 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3705   with `addloop' of the simplifier to faciliate case splitting in premises.
  3706 
  3707 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  3708 in HOL, they strip ALL and --> from proved theorems;
  3709 
  3710 
  3711 
  3712 New in Isabelle94-8 (May 1997)
  3713 ------------------------------
  3714 
  3715 *** General Changes ***
  3716 
  3717 * new utilities to build / run / maintain Isabelle etc. (in parts
  3718 still somewhat experimental); old Makefiles etc. still functional;
  3719 
  3720 * new 'Isabelle System Manual';
  3721 
  3722 * INSTALL text, together with ./configure and ./build scripts;
  3723 
  3724 * reimplemented type inference for greater efficiency, better error
  3725 messages and clean internal interface;
  3726 
  3727 * prlim command for dealing with lots of subgoals (an easier way of
  3728 setting goals_limit);
  3729 
  3730 
  3731 *** Syntax ***
  3732 
  3733 * supports alternative (named) syntax tables (parser and pretty
  3734 printer); internal interface is provided by add_modesyntax(_i);
  3735 
  3736 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  3737 be used in conjunction with the Isabelle symbol font; uses the
  3738 "symbols" syntax table;
  3739 
  3740 * added token_translation interface (may translate name tokens in
  3741 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  3742 the current print_mode); IMPORTANT: user print translation functions
  3743 are responsible for marking newly introduced bounds
  3744 (Syntax.mark_boundT);
  3745 
  3746 * token translations for modes "xterm" and "xterm_color" that display
  3747 names in bold, underline etc. or colors (which requires a color
  3748 version of xterm);
  3749 
  3750 * infixes may now be declared with names independent of their syntax;
  3751 
  3752 * added typed_print_translation (like print_translation, but may
  3753 access type of constant);
  3754 
  3755 
  3756 *** Classical Reasoner ***
  3757 
  3758 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  3759 some limitations.  Blast_tac...
  3760   + ignores addss, addbefore, addafter; this restriction is intrinsic
  3761   + ignores elimination rules that don't have the correct format
  3762         (the conclusion MUST be a formula variable)
  3763   + ignores types, which can make HOL proofs fail
  3764   + rules must not require higher-order unification, e.g. apply_type in ZF
  3765     [message "Function Var's argument not a bound variable" relates to this]
  3766   + its proof strategy is more general but can actually be slower
  3767 
  3768 * substitution with equality assumptions no longer permutes other
  3769 assumptions;
  3770 
  3771 * minor changes in semantics of addafter (now called addaltern); renamed
  3772 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  3773 (and access functions for it);
  3774 
  3775 * improved combination of classical reasoner and simplifier:
  3776   + functions for handling clasimpsets
  3777   + improvement of addss: now the simplifier is called _after_ the
  3778     safe steps.
  3779   + safe variant of addss called addSss: uses safe simplifications
  3780     _during_ the safe steps. It is more complete as it allows multiple
  3781     instantiations of unknowns (e.g. with slow_tac).
  3782 
  3783 *** Simplifier ***
  3784 
  3785 * added interface for simplification procedures (functions that
  3786 produce *proven* rewrite rules on the fly, depending on current
  3787 redex);
  3788 
  3789 * ordering on terms as parameter (used for ordered rewriting);
  3790 
  3791 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  3792 
  3793 * the solver is now split into a safe and an unsafe part.
  3794 This should be invisible for the normal user, except that the
  3795 functions setsolver and addsolver have been renamed to setSolver and
  3796 addSolver; added safe_asm_full_simp_tac;
  3797 
  3798 
  3799 *** HOL ***
  3800 
  3801 * a generic induction tactic `induct_tac' which works for all datatypes and
  3802 also for type `nat';
  3803 
  3804 * a generic case distinction tactic `exhaust_tac' which works for all
  3805 datatypes and also for type `nat';
  3806 
  3807 * each datatype comes with a function `size';
  3808 
  3809 * patterns in case expressions allow tuple patterns as arguments to
  3810 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  3811 
  3812 * primrec now also works with type nat;
  3813 
  3814 * recdef: a new declaration form, allows general recursive functions to be
  3815 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  3816 
  3817 * the constant for negation has been renamed from "not" to "Not" to
  3818 harmonize with FOL, ZF, LK, etc.;
  3819 
  3820 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3821 infinite lists;
  3822 
  3823 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3824 
  3825 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3826 problems in commutative rings, using axiomatic type classes for + and *;
  3827 
  3828 * more examples in HOL/MiniML and HOL/Auth;
  3829 
  3830 * more default rewrite rules for quantifiers, union/intersection;
  3831 
  3832 * a new constant `arbitrary == @x.False';
  3833 
  3834 * HOLCF/IOA replaces old HOL/IOA;
  3835 
  3836 * HOLCF changes: derived all rules and arities
  3837   + axiomatic type classes instead of classes
  3838   + typedef instead of faking type definitions
  3839   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3840   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3841   + eliminated the types void, one, tr
  3842   + use unit lift and bool lift (with translations) instead of one and tr
  3843   + eliminated blift from Lift3.thy (use Def instead of blift)
  3844   all eliminated rules are derived as theorems --> no visible changes ;
  3845 
  3846 
  3847 *** ZF ***
  3848 
  3849 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3850 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3851 as ZF_cs addSIs [equalityI];
  3852 
  3853 
  3854 
  3855 New in Isabelle94-7 (November 96)
  3856 ---------------------------------
  3857 
  3858 * allowing negative levels (as offsets) in prlev and choplev;
  3859 
  3860 * super-linear speedup for large simplifications;
  3861 
  3862 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3863 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3864 FAIL); can suppress it using the command Delsimps (ex_simps @
  3865 all_simps); De Morgan laws are also now included, by default;
  3866 
  3867 * improved printing of ==>  :  ~:
  3868 
  3869 * new object-logic "Sequents" adds linear logic, while replacing LK
  3870 and Modal (thanks to Sara Kalvala);
  3871 
  3872 * HOL/Auth: correctness proofs for authentication protocols;
  3873 
  3874 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3875 examples on HOL/Auth);
  3876 
  3877 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3878 the rewriter and classical reasoner simultaneously;
  3879 
  3880 * function uresult no longer returns theorems in "standard" format;
  3881 regain previous version by: val uresult = standard o uresult;
  3882 
  3883 
  3884 
  3885 New in Isabelle94-6
  3886 -------------------
  3887 
  3888 * oracles -- these establish an interface between Isabelle and trusted
  3889 external reasoners, which may deliver results as theorems;
  3890 
  3891 * proof objects (in particular record all uses of oracles);
  3892 
  3893 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3894 
  3895 * "constdefs" section in theory files;
  3896 
  3897 * "primrec" section (HOL) no longer requires names;
  3898 
  3899 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3900 
  3901 
  3902 
  3903 New in Isabelle94-5
  3904 -------------------
  3905 
  3906 * reduced space requirements;
  3907 
  3908 * automatic HTML generation from theories;
  3909 
  3910 * theory files no longer require "..." (quotes) around most types;
  3911 
  3912 * new examples, including two proofs of the Church-Rosser theorem;
  3913 
  3914 * non-curried (1994) version of HOL is no longer distributed;
  3915 
  3916 
  3917 
  3918 New in Isabelle94-4
  3919 -------------------
  3920 
  3921 * greatly reduced space requirements;
  3922 
  3923 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3924 
  3925 * searchable theorem database (see the section "Retrieving theorems" on
  3926 page 8 of the Reference Manual);
  3927 
  3928 * new examples, including Grabczewski's monumental case study of the
  3929 Axiom of Choice;
  3930 
  3931 * The previous version of HOL renamed to Old_HOL;
  3932 
  3933 * The new version of HOL (previously called CHOL) uses a curried syntax
  3934 for functions.  Application looks like f a b instead of f(a,b);
  3935 
  3936 * Mutually recursive inductive definitions finally work in HOL;
  3937 
  3938 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3939 translates to the operator "split";
  3940 
  3941 
  3942 
  3943 New in Isabelle94-3
  3944 -------------------
  3945 
  3946 * new infix operator, addss, allowing the classical reasoner to
  3947 perform simplification at each step of its search.  Example:
  3948         fast_tac (cs addss ss)
  3949 
  3950 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3951 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3952 look like (a,b) instead of <a,b>;
  3953 
  3954 * PLEASE NOTE: CHOL will eventually replace HOL!
  3955 
  3956 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3957 It translates to the operator "split".  A new theory of integers is available;
  3958 
  3959 * In ZF, integer numerals now denote two's-complement binary integers.
  3960 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3961 
  3962 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3963 of the Axiom of Choice;
  3964 
  3965 
  3966 
  3967 New in Isabelle94-2
  3968 -------------------
  3969 
  3970 * Significantly faster resolution;
  3971 
  3972 * the different sections in a .thy file can now be mixed and repeated
  3973 freely;
  3974 
  3975 * Database of theorems for FOL, HOL and ZF.  New
  3976 commands including qed, qed_goal and bind_thm store theorems in the database.
  3977 
  3978 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3979 a given theory (thms_of), or find out what theory a theorem was proved in
  3980 (theory_of_thm);
  3981 
  3982 * Bugs fixed in the inductive definition and datatype packages;
  3983 
  3984 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3985 and HOL_dup_cs obsolete;
  3986 
  3987 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3988 have been removed;
  3989 
  3990 * Simpler definition of function space in ZF;
  3991 
  3992 * new results about cardinal and ordinal arithmetic in ZF;
  3993 
  3994 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3995 types;
  3996 
  3997 
  3998 $Id$