NEWS
author wenzelm
Tue Jan 03 00:06:18 2006 +0100 (2006-01-03)
changeset 18540 7b6f57406b1b
parent 18536 ab3f32f86847
child 18549 5308a6ea3b96
permissions -rw-r--r--
* Pure/Isar: new command 'unfolding';
* ML/Provers: more generic wrt. syntax of object-logics;
tuned;
     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 duplicated accordingly.  INCOMPATIBILITY, proofs need to be structured
   152 explicitly, e.g. like this:
   153 
   154   lemma
   155     fixes n :: nat
   156     shows "P n" and "Q n"
   157   proof (induct n)
   158     case 01
   159     show "P 0" sorry
   160   next
   161     case 02
   162     show "Q 0" sorry
   163   next
   164     case (Suc1 n)
   165     note `P n` and `Q n`
   166     show "P (Suc n)" sorry
   167   next
   168     case (Suc2 n)
   169     note `P n` and `Q n`
   170     show "Q (Suc n)" sorry
   171   qed
   172 
   173 If simultaneous goals are to be used with mutual rules, the statement
   174 needs to be structured carefully as a two-level conjunction, using
   175 lists of propositions separated by 'and':
   176 
   177   lemma
   178     shows "a : A ==> P1 a"
   179           "a : A ==> P2 a"
   180       and "b : B ==> Q1 b"
   181           "b : B ==> Q2 b"
   182           "b : B ==> Q3 b"
   183   proof (induct set: A B)
   184 
   185 * Provers/induct: support coinduction as well.  See
   186 src/HOL/Library/Coinductive_List.thy for various examples.
   187 
   188 * Provers/classical: removed obsolete classical version of elim_format
   189 attribute; classical elim/dest rules are now treated uniformly when
   190 manipulating the claset.
   191 
   192 * Syntax: input syntax now supports dummy variable binding "%_. b",
   193 where the body does not mention the bound variable.  Note that dummy
   194 patterns implicitly depend on their context of bounds, which makes
   195 "{_. _}" match any set comprehension as expected.  Potential
   196 INCOMPATIBILITY -- parse translations need to cope with syntactic
   197 constant "_idtdummy" in the binding position.
   198 
   199 * Syntax: removed obsolete syntactic constant "_K" and its associated
   200 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
   201 for example "A -> B" => "Pi A (%_. B)".
   202 
   203 
   204 *** HOL ***
   205 
   206 * Alternative iff syntax "A <-> B" for equality on bool (with priority
   207 25 like -->); output depends on the "iff" print_mode, the default is
   208 "A = B" (with priority 50).
   209 
   210 * In the context of the assumption "~(s = t)" the Simplifier rewrites
   211 "t = s" to False (by simproc "neq_simproc").  For backward
   212 compatibility this can be disabled by ML "reset use_neq_simproc".
   213 
   214 * Tactics 'sat' and 'satx' reimplemented, several improvements: goals
   215 no longer need to be stated as "<prems> ==> False", equivalences (i.e.
   216 "=" on type bool) are handled, variable names of the form "lit_<n>"
   217 are no longer reserved, significant speedup.
   218 
   219 * inductive and datatype: provide projections of mutual rules, bundled
   220 as foo_bar.inducts;
   221 
   222 * Library: added theory Coinductive_List of potentially infinite lists
   223 as greatest fixed-point.
   224 
   225 
   226 *** ML ***
   227 
   228 * Pure/library:
   229 
   230   val burrow: ('a list -> 'b list) -> 'a list list -> 'b list list
   231   val burrow_split: ('a list -> 'c * 'b list) -> 'a list list -> 'c * 'b list list
   232 
   233 The semantics of "burrow" is: "take a function with *simulatanously*
   234 transforms a list of value, and apply it *simulatanously* to a list of
   235 list of values of the appropriate type". Confer this with "map" which
   236 would *not* apply its argument function simulatanously but in
   237 sequence. "burrow_split" allows the transformator function to yield an
   238 additional side result.
   239 
   240 Both actually avoid the usage of "unflat" since they hide away
   241 "unflat" from the user.
   242 
   243 * Pure/library: functions map2 and fold2 with curried syntax for
   244 simultanous mapping and folding:
   245 
   246     val map2: ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
   247     val fold2: ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
   248 
   249 * Pure/library: indexed lists - some functions in the Isabelle library
   250 treating lists over 'a as finite mappings from [0...n] to 'a have been
   251 given more convenient names and signatures reminiscent of similar
   252 functions for alists, tables, etc:
   253 
   254   val nth: 'a list -> int -> 'a 
   255   val nth_update: int * 'a -> 'a list -> 'a list
   256   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   257   val fold_index: (int * 'a -> 'b -> 'b) -> 'a list -> 'b -> 'b
   258 
   259 Note that fold_index starts counting at index 0, not 1 like foldln
   260 used to.
   261 
   262 * Pure/General: name_mangler.ML provides a functor for generic name
   263 mangling (bijective mapping from any expression values to strings).
   264 
   265 * Pure/General: rat.ML implements rational numbers.
   266 
   267 * Pure: several functions of signature "... -> theory -> theory * ..."
   268 have been reoriented to "... -> theory -> ... * theory" in order to
   269 allow natural usage in combination with the ||>, ||>>, |-> and
   270 fold_map combinators.
   271 
   272 * Pure: primitive rule lift_rule now takes goal cterm instead of an
   273 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
   274 achieve the old behaviour.
   275 
   276 * Pure: the "Goal" constant is now called "prop", supporting a
   277 slightly more general idea of ``protecting'' meta-level rule
   278 statements.
   279 
   280 * Pure/goals: structure Goal provides simple interfaces for
   281 init/conclude/finish and tactical prove operations (replacing former
   282 Tactic.prove).  Note that OldGoals.prove_goalw_cterm has long been
   283 obsolete, it is ill-behaved in a local proof context (e.g. with local
   284 fixes/assumes or in a locale context).
   285 
   286 * Simplifier: the simpset of a running simplification process now
   287 contains a proof context (cf. Simplifier.the_context), which is the
   288 very context that the initial simpset has been retrieved from (by
   289 simpset_of/local_simpset_of).  Consequently, all plug-in components
   290 (solver, looper etc.) may depend on arbitrary proof data.
   291 
   292 * Simplifier.inherit_context inherits the proof context (plus the
   293 local bounds) of the current simplification process; any simproc
   294 etc. that calls the Simplifier recursively should do this!  Removed
   295 former Simplifier.inherit_bounds, which is already included here --
   296 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
   297 specify an explicit context using Simplifier.context/theory_context.
   298 
   299 * Simplifier/Classical Reasoner: more abstract interfaces
   300 change_simpset/claset for modifying the simpset/claset reference of a
   301 theory; raw versions simpset/claset_ref etc. have been discontinued --
   302 INCOMPATIBILITY.
   303 
   304 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
   305 "Trueprop" etc.
   306 
   307 
   308 
   309 New in Isabelle2005 (October 2005)
   310 ----------------------------------
   311 
   312 *** General ***
   313 
   314 * Theory headers: the new header syntax for Isar theories is
   315 
   316   theory <name>
   317   imports <theory1> ... <theoryN>
   318   uses <file1> ... <fileM>
   319   begin
   320 
   321 where the 'uses' part is optional.  The previous syntax
   322 
   323   theory <name> = <theory1> + ... + <theoryN>:
   324 
   325 will disappear in the next release.  Use isatool fixheaders to convert
   326 existing theory files.  Note that there is no change in ancient
   327 non-Isar theories now, but these will disappear soon.
   328 
   329 * Theory loader: parent theories can now also be referred to via
   330 relative and absolute paths.
   331 
   332 * Command 'find_theorems' searches for a list of criteria instead of a
   333 list of constants. Known criteria are: intro, elim, dest, name:string,
   334 simp:term, and any term. Criteria can be preceded by '-' to select
   335 theorems that do not match. Intro, elim, dest select theorems that
   336 match the current goal, name:s selects theorems whose fully qualified
   337 name contain s, and simp:term selects all simplification rules whose
   338 lhs match term.  Any other term is interpreted as pattern and selects
   339 all theorems matching the pattern. Available in ProofGeneral under
   340 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
   341 
   342   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
   343 
   344 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   345 matching the current goal as introduction rule and not having "HOL."
   346 in their name (i.e. not being defined in theory HOL).
   347 
   348 * Command 'thms_containing' has been discontinued in favour of
   349 'find_theorems'; INCOMPATIBILITY.
   350 
   351 * Communication with Proof General is now 8bit clean, which means that
   352 Unicode text in UTF-8 encoding may be used within theory texts (both
   353 formal and informal parts).  Cf. option -U of the Isabelle Proof
   354 General interface.  Here are some simple examples (cf. src/HOL/ex):
   355 
   356   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
   357   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
   358 
   359 * Improved efficiency of the Simplifier and, to a lesser degree, the
   360 Classical Reasoner.  Typical big applications run around 2 times
   361 faster.
   362 
   363 
   364 *** Document preparation ***
   365 
   366 * Commands 'display_drafts' and 'print_drafts' perform simple output
   367 of raw sources.  Only those symbols that do not require additional
   368 LaTeX packages (depending on comments in isabellesym.sty) are
   369 displayed properly, everything else is left verbatim.  isatool display
   370 and isatool print are used as front ends (these are subject to the
   371 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
   372 
   373 * Command tags control specific markup of certain regions of text,
   374 notably folding and hiding.  Predefined tags include "theory" (for
   375 theory begin and end), "proof" for proof commands, and "ML" for
   376 commands involving ML code; the additional tags "visible" and
   377 "invisible" are unused by default.  Users may give explicit tag
   378 specifications in the text, e.g. ''by %invisible (auto)''.  The
   379 interpretation of tags is determined by the LaTeX job during document
   380 preparation: see option -V of isatool usedir, or options -n and -t of
   381 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
   382 \isadroptag.
   383 
   384 Several document versions may be produced at the same time via isatool
   385 usedir (the generated index.html will link all of them).  Typical
   386 specifications include ''-V document=theory,proof,ML'' to present
   387 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
   388 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
   389 these parts without any formal replacement text.  The Isabelle site
   390 default settings produce ''document'' and ''outline'' versions as
   391 specified above.
   392 
   393 * Several new antiquotations:
   394 
   395   @{term_type term} prints a term with its type annotated;
   396 
   397   @{typeof term} prints the type of a term;
   398 
   399   @{const const} is the same as @{term const}, but checks that the
   400   argument is a known logical constant;
   401 
   402   @{term_style style term} and @{thm_style style thm} print a term or
   403   theorem applying a "style" to it
   404 
   405   @{ML text}
   406 
   407 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
   408 definitions, equations, inequations etc., 'concl' printing only the
   409 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
   410 to print the specified premise.  TermStyle.add_style provides an ML
   411 interface for introducing further styles.  See also the "LaTeX Sugar"
   412 document practical applications.  The ML antiquotation prints
   413 type-checked ML expressions verbatim.
   414 
   415 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
   416 and 'text' support optional locale specification '(in loc)', which
   417 specifies the default context for interpreting antiquotations.  For
   418 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
   419 
   420 * Option 'locale=NAME' of antiquotations specifies an alternative
   421 context interpreting the subsequent argument.  For example: @{thm
   422 [locale=lattice] inf_assoc}.
   423 
   424 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
   425 a proof context.
   426 
   427 * Proper output of antiquotations for theory commands involving a
   428 proof context (such as 'locale' or 'theorem (in loc) ...').
   429 
   430 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
   431 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
   432 
   433 * isatool usedir: new option -C (default true) controls whether option
   434 -D should include a copy of the original document directory; -C false
   435 prevents unwanted effects such as copying of administrative CVS data.
   436 
   437 
   438 *** Pure ***
   439 
   440 * Considerably improved version of 'constdefs' command.  Now performs
   441 automatic type-inference of declared constants; additional support for
   442 local structure declarations (cf. locales and HOL records), see also
   443 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
   444 sequential dependencies of definitions within a single 'constdefs'
   445 section; moreover, the declared name needs to be an identifier.  If
   446 all fails, consider to fall back on 'consts' and 'defs' separately.
   447 
   448 * Improved indexed syntax and implicit structures.  First of all,
   449 indexed syntax provides a notational device for subscripted
   450 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
   451 expressions.  Secondly, in a local context with structure
   452 declarations, number indexes \<^sub>n or the empty index (default
   453 number 1) refer to a certain fixed variable implicitly; option
   454 show_structs controls printing of implicit structures.  Typical
   455 applications of these concepts involve record types and locales.
   456 
   457 * New command 'no_syntax' removes grammar declarations (and
   458 translations) resulting from the given syntax specification, which is
   459 interpreted in the same manner as for the 'syntax' command.
   460 
   461 * 'Advanced' translation functions (parse_translation etc.) may depend
   462 on the signature of the theory context being presently used for
   463 parsing/printing, see also isar-ref manual.
   464 
   465 * Improved 'oracle' command provides a type-safe interface to turn an
   466 ML expression of type theory -> T -> term into a primitive rule of
   467 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
   468 is already included here); see also FOL/ex/IffExample.thy;
   469 INCOMPATIBILITY.
   470 
   471 * axclass: name space prefix for class "c" is now "c_class" (was "c"
   472 before); "cI" is no longer bound, use "c.intro" instead.
   473 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
   474 axclasses vs. locales.
   475 
   476 * Improved internal renaming of symbolic identifiers -- attach primes
   477 instead of base 26 numbers.
   478 
   479 * New flag show_question_marks controls printing of leading question
   480 marks in schematic variable names.
   481 
   482 * In schematic variable names, *any* symbol following \<^isub> or
   483 \<^isup> is now treated as part of the base name.  For example, the
   484 following works without printing of awkward ".0" indexes:
   485 
   486   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   487     by simp
   488 
   489 * Inner syntax includes (*(*nested*) comments*).
   490 
   491 * Pretty printer now supports unbreakable blocks, specified in mixfix
   492 annotations as "(00...)".
   493 
   494 * Clear separation of logical types and nonterminals, where the latter
   495 may only occur in 'syntax' specifications or type abbreviations.
   496 Before that distinction was only partially implemented via type class
   497 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
   498 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
   499 exotic syntax specifications may require further adaption
   500 (e.g. Cube/Cube.thy).
   501 
   502 * Removed obsolete type class "logic", use the top sort {} instead.
   503 Note that non-logical types should be declared as 'nonterminals'
   504 rather than 'types'.  INCOMPATIBILITY for new object-logic
   505 specifications.
   506 
   507 * Attributes 'induct' and 'cases': type or set names may now be
   508 locally fixed variables as well.
   509 
   510 * Simplifier: can now control the depth to which conditional rewriting
   511 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
   512 Limit.
   513 
   514 * Simplifier: simplification procedures may now take the current
   515 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   516 interface), which is very useful for calling the Simplifier
   517 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
   518 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
   519 low-level mk_simproc no longer applies Logic.varify internally, to
   520 allow for use in a context of fixed variables.
   521 
   522 * thin_tac now works even if the assumption being deleted contains !!
   523 or ==>.  More generally, erule now works even if the major premise of
   524 the elimination rule contains !! or ==>.
   525 
   526 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
   527 
   528 * Reorganized bootstrapping of the Pure theories; CPure is now derived
   529 from Pure, which contains all common declarations already.  Both
   530 theories are defined via plain Isabelle/Isar .thy files.
   531 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   532 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
   533 use isatool fixcpure to adapt your theory and ML sources.
   534 
   535 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
   536 selections of theorems in named facts via index ranges.
   537 
   538 * 'print_theorems': in theory mode, really print the difference
   539 wrt. the last state (works for interactive theory development only),
   540 in proof mode print all local facts (cf. 'print_facts');
   541 
   542 * 'hide': option '(open)' hides only base names.
   543 
   544 * More efficient treatment of intermediate checkpoints in interactive
   545 theory development.
   546 
   547 * Code generator is now invoked via code_module (incremental code
   548 generation) and code_library (modular code generation, ML structures
   549 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
   550 must be quoted when used as identifiers.
   551 
   552 * New 'value' command for reading, evaluating and printing terms using
   553 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
   554 quoted when used as identifier.
   555 
   556 
   557 *** Locales ***
   558 
   559 * New commands for the interpretation of locale expressions in
   560 theories (1), locales (2) and proof contexts (3).  These generate
   561 proof obligations from the expression specification.  After the
   562 obligations have been discharged, theorems of the expression are added
   563 to the theory, target locale or proof context.  The synopsis of the
   564 commands is a follows:
   565 
   566   (1) interpretation expr inst
   567   (2) interpretation target < expr
   568   (3) interpret expr inst
   569 
   570 Interpretation in theories and proof contexts require a parameter
   571 instantiation of terms from the current context.  This is applied to
   572 specifications and theorems of the interpreted expression.
   573 Interpretation in locales only permits parameter renaming through the
   574 locale expression.  Interpretation is smart in that interpretations
   575 that are active already do not occur in proof obligations, neither are
   576 instantiated theorems stored in duplicate.  Use 'print_interps' to
   577 inspect active interpretations of a particular locale.  For details,
   578 see the Isar Reference manual.  Examples can be found in
   579 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
   580 
   581 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
   582 'interpret' instead.
   583 
   584 * New context element 'constrains' for adding type constraints to
   585 parameters.
   586 
   587 * Context expressions: renaming of parameters with syntax
   588 redeclaration.
   589 
   590 * Locale declaration: 'includes' disallowed.
   591 
   592 * Proper static binding of attribute syntax -- i.e. types / terms /
   593 facts mentioned as arguments are always those of the locale definition
   594 context, independently of the context of later invocations.  Moreover,
   595 locale operations (renaming and type / term instantiation) are applied
   596 to attribute arguments as expected.
   597 
   598 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
   599 actual attributes; rare situations may require Attrib.attribute to
   600 embed those attributes into Attrib.src that lack concrete syntax.
   601 Attribute implementations need to cooperate properly with the static
   602 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   603 Attrib.XXX_thm etc. already do the right thing without further
   604 intervention.  Only unusual applications -- such as "where" or "of"
   605 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
   606 on the context and the facts involved -- may have to assign parsed
   607 values to argument tokens explicitly.
   608 
   609 * Changed parameter management in theorem generation for long goal
   610 statements with 'includes'.  INCOMPATIBILITY: produces a different
   611 theorem statement in rare situations.
   612 
   613 * Locale inspection command 'print_locale' omits notes elements.  Use
   614 'print_locale!' to have them included in the output.
   615 
   616 
   617 *** Provers ***
   618 
   619 * Provers/hypsubst.ML: improved version of the subst method, for
   620 single-step rewriting: it now works in bound variable contexts. New is
   621 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
   622 rewrite a different subterm than the original subst method, which is
   623 still available as 'simplesubst'.
   624 
   625 * Provers/quasi.ML: new transitivity reasoners for transitivity only
   626 and quasi orders.
   627 
   628 * Provers/trancl.ML: new transitivity reasoner for transitive and
   629 reflexive-transitive closure of relations.
   630 
   631 * Provers/blast.ML: new reference depth_limit to make blast's depth
   632 limit (previously hard-coded with a value of 20) user-definable.
   633 
   634 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   635 is peformed already.  Object-logics merely need to finish their
   636 initial simpset configuration as before.  INCOMPATIBILITY.
   637 
   638 
   639 *** HOL ***
   640 
   641 * Symbolic syntax of Hilbert Choice Operator is now as follows:
   642 
   643   syntax (epsilon)
   644     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   645 
   646 The symbol \<some> is displayed as the alternative epsilon of LaTeX
   647 and x-symbol; use option '-m epsilon' to get it actually printed.
   648 Moreover, the mathematically important symbolic identifier \<epsilon>
   649 becomes available as variable, constant etc.  INCOMPATIBILITY,
   650 
   651 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   652 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   653 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
   654 support corresponding Isar calculations.
   655 
   656 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
   657 instead of ":".
   658 
   659 * theory SetInterval: changed the syntax for open intervals:
   660 
   661   Old       New
   662   {..n(}    {..<n}
   663   {)n..}    {n<..}
   664   {m..n(}   {m..<n}
   665   {)m..n}   {m<..n}
   666   {)m..n(}  {m<..<n}
   667 
   668 The old syntax is still supported but will disappear in the next
   669 release.  For conversion use the following Emacs search and replace
   670 patterns (these are not perfect but work quite well):
   671 
   672   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   673   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   674 
   675 * Theory Commutative_Ring (in Library): method comm_ring for proving
   676 equalities in commutative rings; method 'algebra' provides a generic
   677 interface.
   678 
   679 * Theory Finite_Set: changed the syntax for 'setsum', summation over
   680 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
   681 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
   682 be a tuple pattern.
   683 
   684 Some new syntax forms are available:
   685 
   686   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
   687   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
   688   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
   689   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
   690 
   691 The latter form "\<Sum>x < k. e" used to be based on a separate
   692 function "Summation", which has been discontinued.
   693 
   694 * theory Finite_Set: in structured induction proofs, the insert case
   695 is now 'case (insert x F)' instead of the old counterintuitive 'case
   696 (insert F x)'.
   697 
   698 * The 'refute' command has been extended to support a much larger
   699 fragment of HOL, including axiomatic type classes, constdefs and
   700 typedefs, inductive datatypes and recursion.
   701 
   702 * New tactics 'sat' and 'satx' to prove propositional tautologies.
   703 Requires zChaff with proof generation to be installed.  See
   704 HOL/ex/SAT_Examples.thy for examples.
   705 
   706 * Datatype induction via method 'induct' now preserves the name of the
   707 induction variable. For example, when proving P(xs::'a list) by
   708 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
   709 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
   710 in unstructured proof scripts.
   711 
   712 * Reworked implementation of records.  Improved scalability for
   713 records with many fields, avoiding performance problems for type
   714 inference. Records are no longer composed of nested field types, but
   715 of nested extension types. Therefore the record type only grows linear
   716 in the number of extensions and not in the number of fields.  The
   717 top-level (users) view on records is preserved.  Potential
   718 INCOMPATIBILITY only in strange cases, where the theory depends on the
   719 old record representation. The type generated for a record is called
   720 <record_name>_ext_type.
   721 
   722 Flag record_quick_and_dirty_sensitive can be enabled to skip the
   723 proofs triggered by a record definition or a simproc (if
   724 quick_and_dirty is enabled).  Definitions of large records can take
   725 quite long.
   726 
   727 New simproc record_upd_simproc for simplification of multiple record
   728 updates enabled by default.  Moreover, trivial updates are also
   729 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   730 occasionally, since simplification is more powerful by default.
   731 
   732 * typedef: proper support for polymorphic sets, which contain extra
   733 type-variables in the term.
   734 
   735 * Simplifier: automatically reasons about transitivity chains
   736 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
   737 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
   738 old proofs break occasionally as simplification may now solve more
   739 goals than previously.
   740 
   741 * Simplifier: converts x <= y into x = y if assumption y <= x is
   742 present.  Works for all partial orders (class "order"), in particular
   743 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
   744 just like y <= x.
   745 
   746 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
   747 bound variable or a constant then the let is unfolded.  Otherwise
   748 first a is simplified to b, and then f b is simplified to g. If
   749 possible we abstract b from g arriving at "let x = b in h x",
   750 otherwise we unfold the let and arrive at g.  The simproc can be
   751 enabled/disabled by the reference use_let_simproc.  Potential
   752 INCOMPATIBILITY since simplification is more powerful by default.
   753 
   754 * Classical reasoning: the meson method now accepts theorems as arguments.
   755 
   756 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
   757 jobs to provide advice on the provability of subgoals.
   758 
   759 * Theory OrderedGroup and Ring_and_Field: various additions and
   760 improvements to faciliate calculations involving equalities and
   761 inequalities.
   762 
   763 The following theorems have been eliminated or modified
   764 (INCOMPATIBILITY):
   765 
   766   abs_eq             now named abs_of_nonneg
   767   abs_of_ge_0        now named abs_of_nonneg
   768   abs_minus_eq       now named abs_of_nonpos
   769   imp_abs_id         now named abs_of_nonneg
   770   imp_abs_neg_id     now named abs_of_nonpos
   771   mult_pos           now named mult_pos_pos
   772   mult_pos_le        now named mult_nonneg_nonneg
   773   mult_pos_neg_le    now named mult_nonneg_nonpos
   774   mult_pos_neg2_le   now named mult_nonneg_nonpos2
   775   mult_neg           now named mult_neg_neg
   776   mult_neg_le        now named mult_nonpos_nonpos
   777 
   778 * Theory Parity: added rules for simplifying exponents.
   779 
   780 * Theory List:
   781 
   782 The following theorems have been eliminated or modified
   783 (INCOMPATIBILITY):
   784 
   785   list_all_Nil       now named list_all.simps(1)
   786   list_all_Cons      now named list_all.simps(2)
   787   list_all_conv      now named list_all_iff
   788   set_mem_eq         now named mem_iff
   789 
   790 * Theories SetsAndFunctions and BigO (see HOL/Library) support
   791 asymptotic "big O" calculations.  See the notes in BigO.thy.
   792 
   793 
   794 *** HOL-Complex ***
   795 
   796 * Theory RealDef: better support for embedding natural numbers and
   797 integers in the reals.
   798 
   799 The following theorems have been eliminated or modified
   800 (INCOMPATIBILITY):
   801 
   802   exp_ge_add_one_self  now requires no hypotheses
   803   real_of_int_add      reversed direction of equality (use [symmetric])
   804   real_of_int_minus    reversed direction of equality (use [symmetric])
   805   real_of_int_diff     reversed direction of equality (use [symmetric])
   806   real_of_int_mult     reversed direction of equality (use [symmetric])
   807 
   808 * Theory RComplete: expanded support for floor and ceiling functions.
   809 
   810 * Theory Ln is new, with properties of the natural logarithm
   811 
   812 * Hyperreal: There is a new type constructor "star" for making
   813 nonstandard types.  The old type names are now type synonyms:
   814 
   815   hypreal = real star
   816   hypnat = nat star
   817   hcomplex = complex star
   818 
   819 * Hyperreal: Many groups of similarly-defined constants have been
   820 replaced by polymorphic versions (INCOMPATIBILITY):
   821 
   822   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
   823 
   824   starset      <-- starsetNat, starsetC
   825   *s*          <-- *sNat*, *sc*
   826   starset_n    <-- starsetNat_n, starsetC_n
   827   *sn*         <-- *sNatn*, *scn*
   828   InternalSets <-- InternalNatSets, InternalCSets
   829 
   830   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
   831   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
   832   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
   833   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
   834   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
   835 
   836 * Hyperreal: Many type-specific theorems have been removed in favor of
   837 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
   838 
   839   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
   840   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
   841   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
   842   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
   843   right_minus <-- hypreal_add_minus
   844   left_minus <-- {hypreal,hcomplex}_add_minus_left
   845   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
   846   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
   847   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
   848   mult_1_right <-- hcomplex_mult_one_right
   849   mult_zero_left <-- hcomplex_mult_zero_left
   850   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
   851   right_distrib <-- hypnat_add_mult_distrib2
   852   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
   853   right_inverse <-- hypreal_mult_inverse
   854   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
   855   order_refl <-- {hypreal,hypnat}_le_refl
   856   order_trans <-- {hypreal,hypnat}_le_trans
   857   order_antisym <-- {hypreal,hypnat}_le_anti_sym
   858   order_less_le <-- {hypreal,hypnat}_less_le
   859   linorder_linear <-- {hypreal,hypnat}_le_linear
   860   add_left_mono <-- {hypreal,hypnat}_add_left_mono
   861   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
   862   add_nonneg_nonneg <-- hypreal_le_add_order
   863 
   864 * Hyperreal: Separate theorems having to do with type-specific
   865 versions of constants have been merged into theorems that apply to the
   866 new polymorphic constants (INCOMPATIBILITY):
   867 
   868   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
   869   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
   870   STAR_Un <-- {STAR,NatStar,STARC}_Un
   871   STAR_Int <-- {STAR,NatStar,STARC}_Int
   872   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
   873   STAR_subset <-- {STAR,NatStar,STARC}_subset
   874   STAR_mem <-- {STAR,NatStar,STARC}_mem
   875   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
   876   STAR_diff <-- {STAR,STARC}_diff
   877   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
   878     STARC_hcomplex_of_complex}_image_subset
   879   starset_n_Un <-- starset{Nat,C}_n_Un
   880   starset_n_Int <-- starset{Nat,C}_n_Int
   881   starset_n_Compl <-- starset{Nat,C}_n_Compl
   882   starset_n_diff <-- starset{Nat,C}_n_diff
   883   InternalSets_Un <-- Internal{Nat,C}Sets_Un
   884   InternalSets_Int <-- Internal{Nat,C}Sets_Int
   885   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
   886   InternalSets_diff <-- Internal{Nat,C}Sets_diff
   887   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
   888   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
   889   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
   890   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
   891   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
   892   starfun <-- starfun{Nat,Nat2,C,RC,CR}
   893   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
   894   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
   895   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
   896   starfun_diff <-- starfun{C,RC,CR}_diff
   897   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
   898   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
   899   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
   900   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
   901   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
   902   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
   903   starfun_Id <-- starfunC_Id
   904   starfun_approx <-- starfun{Nat,CR}_approx
   905   starfun_capprox <-- starfun{C,RC}_capprox
   906   starfun_abs <-- starfunNat_rabs
   907   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
   908   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
   909   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
   910   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
   911   starfun_add_capprox <-- starfun{C,RC}_add_capprox
   912   starfun_add_approx <-- starfunCR_add_approx
   913   starfun_inverse_inverse <-- starfunC_inverse_inverse
   914   starfun_divide <-- starfun{C,CR,RC}_divide
   915   starfun_n <-- starfun{Nat,C}_n
   916   starfun_n_mult <-- starfun{Nat,C}_n_mult
   917   starfun_n_add <-- starfun{Nat,C}_n_add
   918   starfun_n_add_minus <-- starfunNat_n_add_minus
   919   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
   920   starfun_n_minus <-- starfun{Nat,C}_n_minus
   921   starfun_n_eq <-- starfun{Nat,C}_n_eq
   922 
   923   star_n_add <-- {hypreal,hypnat,hcomplex}_add
   924   star_n_minus <-- {hypreal,hcomplex}_minus
   925   star_n_diff <-- {hypreal,hcomplex}_diff
   926   star_n_mult <-- {hypreal,hcomplex}_mult
   927   star_n_inverse <-- {hypreal,hcomplex}_inverse
   928   star_n_le <-- {hypreal,hypnat}_le
   929   star_n_less <-- {hypreal,hypnat}_less
   930   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
   931   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
   932   star_n_abs <-- hypreal_hrabs
   933   star_n_divide <-- hcomplex_divide
   934 
   935   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
   936   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
   937   star_of_diff <-- hypreal_of_real_diff
   938   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
   939   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
   940   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
   941   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
   942   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
   943   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
   944   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
   945   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
   946   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
   947   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
   948   star_of_number_of <-- {hypreal,hcomplex}_number_of
   949   star_of_number_less <-- number_of_less_hypreal_of_real_iff
   950   star_of_number_le <-- number_of_le_hypreal_of_real_iff
   951   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
   952   star_of_less_number <-- hypreal_of_real_less_number_of_iff
   953   star_of_le_number <-- hypreal_of_real_le_number_of_iff
   954   star_of_power <-- hypreal_of_real_power
   955   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
   956 
   957 * Hyperreal: new method "transfer" that implements the transfer
   958 principle of nonstandard analysis. With a subgoal that mentions
   959 nonstandard types like "'a star", the command "apply transfer"
   960 replaces it with an equivalent one that mentions only standard types.
   961 To be successful, all free variables must have standard types; non-
   962 standard variables must have explicit universal quantifiers.
   963 
   964 * Hyperreal: A theory of Taylor series.
   965 
   966 
   967 *** HOLCF ***
   968 
   969 * Discontinued special version of 'constdefs' (which used to support
   970 continuous functions) in favor of the general Pure one with full
   971 type-inference.
   972 
   973 * New simplification procedure for solving continuity conditions; it
   974 is much faster on terms with many nested lambda abstractions (cubic
   975 instead of exponential time).
   976 
   977 * New syntax for domain package: selector names are now optional.
   978 Parentheses should be omitted unless argument is lazy, for example:
   979 
   980   domain 'a stream = cons "'a" (lazy "'a stream")
   981 
   982 * New command 'fixrec' for defining recursive functions with pattern
   983 matching; defining multiple functions with mutual recursion is also
   984 supported.  Patterns may include the constants cpair, spair, up, sinl,
   985 sinr, or any data constructor defined by the domain package. The given
   986 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
   987 syntax and examples.
   988 
   989 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
   990 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
   991 but the proof obligation additionally includes an admissibility
   992 requirement. The packages generate instances of class cpo or pcpo,
   993 with continuity and strictness theorems for Rep and Abs.
   994 
   995 * HOLCF: Many theorems have been renamed according to a more standard naming
   996 scheme (INCOMPATIBILITY):
   997 
   998   foo_inject:  "foo$x = foo$y ==> x = y"
   999   foo_eq:      "(foo$x = foo$y) = (x = y)"
  1000   foo_less:    "(foo$x << foo$y) = (x << y)"
  1001   foo_strict:  "foo$UU = UU"
  1002   foo_defined: "... ==> foo$x ~= UU"
  1003   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  1004 
  1005 
  1006 *** ZF ***
  1007 
  1008 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  1009 including the First Isomorphism Theorem (on quotienting by the kernel
  1010 of a homomorphism).
  1011 
  1012 * ZF/Simplifier: install second copy of type solver that actually
  1013 makes use of TC rules declared to Isar proof contexts (or locales);
  1014 the old version is still required for ML proof scripts.
  1015 
  1016 
  1017 *** Cube ***
  1018 
  1019 * Converted to Isar theory format; use locales instead of axiomatic
  1020 theories.
  1021 
  1022 
  1023 *** ML ***
  1024 
  1025 * Pure/library.ML no longer defines its own option datatype, but uses
  1026 that of the SML basis, which has constructors NONE and SOME instead of
  1027 None and Some, as well as exception Option.Option instead of OPTION.
  1028 The functions the, if_none, is_some, is_none have been adapted
  1029 accordingly, while Option.map replaces apsome.
  1030 
  1031 * Pure/library.ML: the exception LIST has been given up in favour of
  1032 the standard exceptions Empty and Subscript, as well as
  1033 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  1034 superceded by the standard hd and tl functions etc.
  1035 
  1036 A number of basic list functions are no longer exported to the ML
  1037 toplevel, as they are variants of predefined functions.  The following
  1038 suggests how one can translate existing code:
  1039 
  1040     rev_append xs ys = List.revAppend (xs, ys)
  1041     nth_elem (i, xs) = List.nth (xs, i)
  1042     last_elem xs = List.last xs
  1043     flat xss = List.concat xss
  1044     seq fs = List.app fs
  1045     partition P xs = List.partition P xs
  1046     mapfilter f xs = List.mapPartial f xs
  1047 
  1048 * Pure/library.ML: several combinators for linear functional
  1049 transformations, notably reverse application and composition:
  1050 
  1051   x |> f                f #> g
  1052   (x, y) |-> f          f #-> g
  1053 
  1054 * Pure/library.ML: introduced/changed precedence of infix operators:
  1055 
  1056   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  1057   infix 2 ?;
  1058   infix 3 o oo ooo oooo;
  1059   infix 4 ~~ upto downto;
  1060 
  1061 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  1062 infix operators.
  1063 
  1064 * Pure/library.ML: natural list combinators fold, fold_rev, and
  1065 fold_map support linear functional transformations and nesting.  For
  1066 example:
  1067 
  1068   fold f [x1, ..., xN] y =
  1069     y |> f x1 |> ... |> f xN
  1070 
  1071   (fold o fold) f [xs1, ..., xsN] y =
  1072     y |> fold f xs1 |> ... |> fold f xsN
  1073 
  1074   fold f [x1, ..., xN] =
  1075     f x1 #> ... #> f xN
  1076 
  1077   (fold o fold) f [xs1, ..., xsN] =
  1078     fold f xs1 #> ... #> fold f xsN
  1079 
  1080 * Pure/library.ML: the following selectors on type 'a option are
  1081 available:
  1082 
  1083   the:               'a option -> 'a  (*partial*)
  1084   these:             'a option -> 'a  where 'a = 'b list
  1085   the_default: 'a -> 'a option -> 'a
  1086   the_list:          'a option -> 'a list
  1087 
  1088 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1089 basic operations for association lists, following natural argument
  1090 order; moreover the explicit equality predicate passed here avoids
  1091 potentially expensive polymorphic runtime equality checks.
  1092 The old functions may be expressed as follows:
  1093 
  1094   assoc = uncurry (AList.lookup (op =))
  1095   assocs = these oo AList.lookup (op =)
  1096   overwrite = uncurry (AList.update (op =)) o swap
  1097 
  1098 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  1099 
  1100   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  1101   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  1102 
  1103 replacing make_keylist and keyfilter (occassionally used)
  1104 Naive rewrites:
  1105 
  1106   make_keylist = AList.make
  1107   keyfilter = AList.find (op =)
  1108 
  1109 * eq_fst and eq_snd now take explicit equality parameter, thus
  1110   avoiding eqtypes. Naive rewrites:
  1111 
  1112     eq_fst = eq_fst (op =)
  1113     eq_snd = eq_snd (op =)
  1114 
  1115 * Removed deprecated apl and apr (rarely used).
  1116   Naive rewrites:
  1117 
  1118     apl (n, op) =>>= curry op n
  1119     apr (op, m) =>>= fn n => op (n, m)
  1120 
  1121 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  1122 provides a reasonably efficient light-weight implementation of sets as
  1123 lists.
  1124 
  1125 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  1126 few new operations; existing lookup and update are now curried to
  1127 follow natural argument order (for use with fold etc.);
  1128 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  1129 
  1130 * Pure/General: output via the Isabelle channels of
  1131 writeln/warning/error etc. is now passed through Output.output, with a
  1132 hook for arbitrary transformations depending on the print_mode
  1133 (cf. Output.add_mode -- the first active mode that provides a output
  1134 function wins).  Already formatted output may be embedded into further
  1135 text via Output.raw; the result of Pretty.string_of/str_of and derived
  1136 functions (string_of_term/cterm/thm etc.) is already marked raw to
  1137 accommodate easy composition of diagnostic messages etc.  Programmers
  1138 rarely need to care about Output.output or Output.raw at all, with
  1139 some notable exceptions: Output.output is required when bypassing the
  1140 standard channels (writeln etc.), or in token translations to produce
  1141 properly formatted results; Output.raw is required when capturing
  1142 already output material that will eventually be presented to the user
  1143 a second time.  For the default print mode, both Output.output and
  1144 Output.raw have no effect.
  1145 
  1146 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  1147 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  1148 cumulative results are displayed at the end of a batch session.
  1149 
  1150 * Pure/General: File.sysify_path and File.quote_sysify path have been
  1151 replaced by File.platform_path and File.shell_path (with appropriate
  1152 hooks).  This provides a clean interface for unusual systems where the
  1153 internal and external process view of file names are different.
  1154 
  1155 * Pure: more efficient orders for basic syntactic entities: added
  1156 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  1157 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  1158 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  1159 orders now -- potential INCOMPATIBILITY for code that depends on a
  1160 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  1161 Library.sort_strings on result).
  1162 
  1163 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  1164 fold_types traverse types/terms from left to right, observing natural
  1165 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  1166 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  1167 
  1168 * Pure: name spaces have been refined, with significant changes of the
  1169 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  1170 to extern(_table).  The plain name entry path is superceded by a
  1171 general 'naming' context, which also includes the 'policy' to produce
  1172 a fully qualified name and external accesses of a fully qualified
  1173 name; NameSpace.extend is superceded by context dependent
  1174 Sign.declare_name.  Several theory and proof context operations modify
  1175 the naming context.  Especially note Theory.restore_naming and
  1176 ProofContext.restore_naming to get back to a sane state; note that
  1177 Theory.add_path is no longer sufficient to recover from
  1178 Theory.absolute_path in particular.
  1179 
  1180 * Pure: new flags short_names (default false) and unique_names
  1181 (default true) for controlling output of qualified names.  If
  1182 short_names is set, names are printed unqualified.  If unique_names is
  1183 reset, the name prefix is reduced to the minimum required to achieve
  1184 the original result when interning again, even if there is an overlap
  1185 with earlier declarations.
  1186 
  1187 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  1188 now 'extend', and 'merge' gets an additional Pretty.pp argument
  1189 (useful for printing error messages).  INCOMPATIBILITY.
  1190 
  1191 * Pure: major reorganization of the theory context.  Type Sign.sg and
  1192 Theory.theory are now identified, referring to the universal
  1193 Context.theory (see Pure/context.ML).  Actual signature and theory
  1194 content is managed as theory data.  The old code and interfaces were
  1195 spread over many files and structures; the new arrangement introduces
  1196 considerable INCOMPATIBILITY to gain more clarity:
  1197 
  1198   Context -- theory management operations (name, identity, inclusion,
  1199     parents, ancestors, merge, etc.), plus generic theory data;
  1200 
  1201   Sign -- logical signature and syntax operations (declaring consts,
  1202     types, etc.), plus certify/read for common entities;
  1203 
  1204   Theory -- logical theory operations (stating axioms, definitions,
  1205     oracles), plus a copy of logical signature operations (consts,
  1206     types, etc.); also a few basic management operations (Theory.copy,
  1207     Theory.merge, etc.)
  1208 
  1209 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  1210 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  1211 for convenience -- they merely return the theory.
  1212 
  1213 * Pure: type Type.tsig is superceded by theory in most interfaces.
  1214 
  1215 * Pure: the Isar proof context type is already defined early in Pure
  1216 as Context.proof (note that ProofContext.context and Proof.context are
  1217 aliases, where the latter is the preferred name).  This enables other
  1218 Isabelle components to refer to that type even before Isar is present.
  1219 
  1220 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  1221 typeK, constK, axiomK, oracleK), but provide explicit operations for
  1222 any of these kinds.  For example, Sign.intern typeK is now
  1223 Sign.intern_type, Theory.hide_space Sign.typeK is now
  1224 Theory.hide_types.  Also note that former
  1225 Theory.hide_classes/types/consts are now
  1226 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  1227 internalize their arguments!  INCOMPATIBILITY.
  1228 
  1229 * Pure: get_thm interface (of PureThy and ProofContext) expects
  1230 datatype thmref (with constructors Name and NameSelection) instead of
  1231 plain string -- INCOMPATIBILITY;
  1232 
  1233 * Pure: cases produced by proof methods specify options, where NONE
  1234 means to remove case bindings -- INCOMPATIBILITY in
  1235 (RAW_)METHOD_CASES.
  1236 
  1237 * Pure: the following operations retrieve axioms or theorems from a
  1238 theory node or theory hierarchy, respectively:
  1239 
  1240   Theory.axioms_of: theory -> (string * term) list
  1241   Theory.all_axioms_of: theory -> (string * term) list
  1242   PureThy.thms_of: theory -> (string * thm) list
  1243   PureThy.all_thms_of: theory -> (string * thm) list
  1244 
  1245 * Pure: print_tac now outputs the goal through the trace channel.
  1246 
  1247 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  1248 Reference Toplevel.debug (default false) controls detailed printing
  1249 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  1250 controls execution profiling -- set to 1 for time and 2 for space
  1251 (both increase the runtime).
  1252 
  1253 * Isar session: The initial use of ROOT.ML is now always timed,
  1254 i.e. the log will show the actual process times, in contrast to the
  1255 elapsed wall-clock time that the outer shell wrapper produces.
  1256 
  1257 * Simplifier: improved handling of bound variables (nameless
  1258 representation, avoid allocating new strings).  Simprocs that invoke
  1259 the Simplifier recursively should use Simplifier.inherit_bounds to
  1260 avoid local name clashes.  Failure to do so produces warnings
  1261 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  1262 for further details.
  1263 
  1264 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  1265 bindings for all theorems stored within a given theory; this may help
  1266 in porting non-Isar theories to Isar ones, while keeping ML proof
  1267 scripts for the time being.
  1268 
  1269 * ML operator HTML.with_charset specifies the charset begin used for
  1270 generated HTML files.  For example:
  1271 
  1272   HTML.with_charset "utf-8" use_thy "Hebrew";
  1273   HTML.with_charset "utf-8" use_thy "Chinese";
  1274 
  1275 
  1276 *** System ***
  1277 
  1278 * Allow symlinks to all proper Isabelle executables (Isabelle,
  1279 isabelle, isatool etc.).
  1280 
  1281 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  1282 isatool doc, isatool mkdir, display_drafts etc.).
  1283 
  1284 * isatool usedir: option -f allows specification of the ML file to be
  1285 used by Isabelle; default is ROOT.ML.
  1286 
  1287 * New isatool version outputs the version identifier of the Isabelle
  1288 distribution being used.
  1289 
  1290 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  1291 (containing Boolean satisfiability problems) into Isabelle/HOL
  1292 theories.
  1293 
  1294 
  1295 
  1296 New in Isabelle2004 (April 2004)
  1297 --------------------------------
  1298 
  1299 *** General ***
  1300 
  1301 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  1302   Replaces linorder.ML.
  1303 
  1304 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  1305   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  1306   (\<a>...\<z>), are now considered normal letters, and can therefore
  1307   be used anywhere where an ASCII letter (a...zA...Z) has until
  1308   now. COMPATIBILITY: This obviously changes the parsing of some
  1309   terms, especially where a symbol has been used as a binder, say
  1310   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  1311   as an identifier.  Fix it by inserting a space around former
  1312   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  1313   existing theory and ML files.
  1314 
  1315 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  1316 
  1317 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  1318   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  1319   a normal (but invisible) letter. For multiple letter subscripts repeat
  1320   \<^isub> like this: x\<^isub>1\<^isub>2.
  1321 
  1322 * Pure: There are now sub-/superscripts that can span more than one
  1323   character. Text between \<^bsub> and \<^esub> is set in subscript in
  1324   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  1325   superscript. The new control characters are not identifier parts.
  1326 
  1327 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  1328   content of "..." to the latex file instead of \isacntrl... . The "..."
  1329   may consist of any printable characters excluding the end bracket >.
  1330 
  1331 * Pure: Using new Isar command "finalconsts" (or the ML functions
  1332   Theory.add_finals or Theory.add_finals_i) it is now possible to
  1333   declare constants "final", which prevents their being given a definition
  1334   later.  It is useful for constants whose behaviour is fixed axiomatically
  1335   rather than definitionally, such as the meta-logic connectives.
  1336 
  1337 * Pure: 'instance' now handles general arities with general sorts
  1338   (i.e. intersections of classes),
  1339 
  1340 * Presentation: generated HTML now uses a CSS style sheet to make layout
  1341   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  1342   It can be changed to alter the colors/layout of generated pages.
  1343 
  1344 
  1345 *** Isar ***
  1346 
  1347 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  1348   cut_tac, subgoal_tac and thin_tac:
  1349   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  1350     locales are no longer forced to write Isar proof scripts.
  1351     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  1352     emulations.
  1353   - INCOMPATIBILITY: names of variables to be instantiated may no
  1354     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  1355     This is consistent with the instantiation attribute "where".
  1356 
  1357 * Attributes "where" and "of":
  1358   - Now take type variables of instantiated theorem into account when reading
  1359     the instantiation string.  This fixes a bug that caused instantiated
  1360     theorems to have too special types in some circumstances.
  1361   - "where" permits explicit instantiations of type variables.
  1362 
  1363 * Calculation commands "moreover" and "also" no longer interfere with
  1364   current facts ("this"), admitting arbitrary combinations with "then"
  1365   and derived forms.
  1366 
  1367 * Locales:
  1368   - Goal statements involving the context element "includes" no longer
  1369     generate theorems with internal delta predicates (those ending on
  1370     "_axioms") in the premise.
  1371     Resolve particular premise with <locale>.intro to obtain old form.
  1372   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  1373     specification and "includes" elements in goal statement.
  1374   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  1375     [intro?] and [elim?] (respectively) by default.
  1376   - Experimental command for instantiation of locales in proof contexts:
  1377         instantiate <label>[<attrs>]: <loc>
  1378     Instantiates locale <loc> and adds all its theorems to the current context
  1379     taking into account their attributes.  Label and attrs are optional
  1380     modifiers, like in theorem declarations.  If present, names of
  1381     instantiated theorems are qualified with <label>, and the attributes
  1382     <attrs> are applied after any attributes these theorems might have already.
  1383       If the locale has assumptions, a chained fact of the form
  1384     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  1385     are derived.  The command does not support old-style locales declared
  1386     with "locale (open)".
  1387       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  1388 
  1389 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  1390   (Isar) contexts.
  1391 
  1392 
  1393 *** HOL ***
  1394 
  1395 * Proof import: new image HOL4 contains the imported library from
  1396   the HOL4 system with about 2500 theorems. It is imported by
  1397   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  1398   can be used like any other Isabelle image.  See
  1399   HOL/Import/HOL/README for more information.
  1400 
  1401 * Simplifier:
  1402   - Much improved handling of linear and partial orders.
  1403     Reasoners for linear and partial orders are set up for type classes
  1404     "linorder" and "order" respectively, and are added to the default simpset
  1405     as solvers.  This means that the simplifier can build transitivity chains
  1406     to solve goals from the assumptions.
  1407   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  1408     of blast or auto after simplification become unnecessary because the goal
  1409     is solved by simplification already.
  1410 
  1411 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  1412     all proved in axiomatic type classes for semirings, rings and fields.
  1413 
  1414 * Numerics:
  1415   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  1416     now formalized using the Ring_and_Field theory mentioned above.
  1417   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  1418     than before, because now they are set up once in a generic manner.
  1419   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  1420     Look for the general versions in Ring_and_Field (and Power if they concern
  1421     exponentiation).
  1422 
  1423 * Type "rat" of the rational numbers is now available in HOL-Complex.
  1424 
  1425 * Records:
  1426   - Record types are now by default printed with their type abbreviation
  1427     instead of the list of all field types. This can be configured via
  1428     the reference "print_record_type_abbr".
  1429   - Simproc "record_upd_simproc" for simplification of multiple updates added
  1430     (not enabled by default).
  1431   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  1432     EX x. x = sel r to True (not enabled by default).
  1433   - Tactic "record_split_simp_tac" to split and simplify records added.
  1434 
  1435 * 'specification' command added, allowing for definition by
  1436   specification.  There is also an 'ax_specification' command that
  1437   introduces the new constants axiomatically.
  1438 
  1439 * arith(_tac) is now able to generate counterexamples for reals as well.
  1440 
  1441 * HOL-Algebra: new locale "ring" for non-commutative rings.
  1442 
  1443 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  1444   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  1445 
  1446 * HOL-Matrix: a first theory for matrices in HOL with an application of
  1447   matrix theory to linear programming.
  1448 
  1449 * Unions and Intersections:
  1450   The latex output syntax of UN and INT has been changed
  1451   from "\Union x \in A. B" to "\Union_{x \in A} B"
  1452   i.e. the index formulae has become a subscript.
  1453   Similarly for "\Union x. B", and for \Inter instead of \Union.
  1454 
  1455 * Unions and Intersections over Intervals:
  1456   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  1457   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  1458   like in normal math, and corresponding versions for < and for intersection.
  1459 
  1460 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  1461   lexicographic dictonary ordering has been added as "lexord".
  1462 
  1463 * ML: the legacy theory structures Int and List have been removed. They had
  1464   conflicted with ML Basis Library structures having the same names.
  1465 
  1466 * 'refute' command added to search for (finite) countermodels.  Only works
  1467   for a fragment of HOL.  The installation of an external SAT solver is
  1468   highly recommended.  See "HOL/Refute.thy" for details.
  1469 
  1470 * 'quickcheck' command: Allows to find counterexamples by evaluating
  1471   formulae under an assignment of free variables to random values.
  1472   In contrast to 'refute', it can deal with inductive datatypes,
  1473   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  1474   for examples.
  1475 
  1476 
  1477 *** HOLCF ***
  1478 
  1479 * Streams now come with concatenation and are part of the HOLCF image
  1480 
  1481 
  1482 
  1483 New in Isabelle2003 (May 2003)
  1484 ------------------------------
  1485 
  1486 *** General ***
  1487 
  1488 * Provers/simplifier:
  1489 
  1490   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  1491     Assumptions are now subject to complete mutual simplification,
  1492     not just from left to right. The simplifier now preserves
  1493     the order of assumptions.
  1494 
  1495     Potential INCOMPATIBILITY:
  1496 
  1497     -- simp sometimes diverges where the old version did
  1498        not, e.g. invoking simp on the goal
  1499 
  1500         [| P (f x); y = x; f x = f y |] ==> Q
  1501 
  1502        now gives rise to the infinite reduction sequence
  1503 
  1504         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  1505 
  1506        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  1507        kind of problem.
  1508 
  1509     -- Tactics combining classical reasoner and simplification (such as auto)
  1510        are also affected by this change, because many of them rely on
  1511        simp. They may sometimes diverge as well or yield a different numbers
  1512        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  1513        in case of problems. Sometimes subsequent calls to the classical
  1514        reasoner will fail because a preceeding call to the simplifier too
  1515        eagerly simplified the goal, e.g. deleted redundant premises.
  1516 
  1517   - The simplifier trace now shows the names of the applied rewrite rules
  1518 
  1519   - You can limit the number of recursive invocations of the simplifier
  1520     during conditional rewriting (where the simplifie tries to solve the
  1521     conditions before applying the rewrite rule):
  1522     ML "simp_depth_limit := n"
  1523     where n is an integer. Thus you can force termination where previously
  1524     the simplifier would diverge.
  1525 
  1526   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  1527 
  1528   - No longer aborts on failed congruence proof.  Instead, the
  1529     congruence is ignored.
  1530 
  1531 * Pure: New generic framework for extracting programs from constructive
  1532   proofs. See HOL/Extraction.thy for an example instantiation, as well
  1533   as HOL/Extraction for some case studies.
  1534 
  1535 * Pure: The main goal of the proof state is no longer shown by default, only
  1536 the subgoals. This behaviour is controlled by a new flag.
  1537    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  1538 (ML: Proof.show_main_goal).
  1539 
  1540 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  1541 rules whose conclusion matches subgoal 1:
  1542       PG menu: Isabelle/Isar -> Show me -> matching rules
  1543 The rules are ordered by how closely they match the subgoal.
  1544 In particular, rules that solve a subgoal outright are displayed first
  1545 (or rather last, the way they are printed).
  1546 (ML: ProofGeneral.print_intros())
  1547 
  1548 * Pure: New flag trace_unify_fail causes unification to print
  1549 diagnostic information (PG: in trace buffer) when it fails. This is
  1550 useful for figuring out why single step proofs like rule, erule or
  1551 assumption failed.
  1552 
  1553 * Pure: Locale specifications now produce predicate definitions
  1554 according to the body of text (covering assumptions modulo local
  1555 definitions); predicate "loc_axioms" covers newly introduced text,
  1556 while "loc" is cumulative wrt. all included locale expressions; the
  1557 latter view is presented only on export into the global theory
  1558 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  1559 on the old view without predicates;
  1560 
  1561 * Pure: predefined locales "var" and "struct" are useful for sharing
  1562 parameters (as in CASL, for example); just specify something like
  1563 ``var x + var y + struct M'' as import;
  1564 
  1565 * Pure: improved thms_containing: proper indexing of facts instead of
  1566 raw theorems; check validity of results wrt. current name space;
  1567 include local facts of proof configuration (also covers active
  1568 locales), cover fixed variables in index; may use "_" in term
  1569 specification; an optional limit for the number of printed facts may
  1570 be given (the default is 40);
  1571 
  1572 * Pure: disallow duplicate fact bindings within new-style theory files
  1573 (batch-mode only);
  1574 
  1575 * Provers: improved induct method: assumptions introduced by case
  1576 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  1577 the goal statement); "foo" still refers to all facts collectively;
  1578 
  1579 * Provers: the function blast.overloaded has been removed: all constants
  1580 are regarded as potentially overloaded, which improves robustness in exchange
  1581 for slight decrease in efficiency;
  1582 
  1583 * Provers/linorder: New generic prover for transitivity reasoning over
  1584 linear orders.  Note: this prover is not efficient!
  1585 
  1586 * Isar: preview of problems to finish 'show' now produce an error
  1587 rather than just a warning (in interactive mode);
  1588 
  1589 
  1590 *** HOL ***
  1591 
  1592 * arith(_tac)
  1593 
  1594  - Produces a counter example if it cannot prove a goal.
  1595    Note that the counter example may be spurious if the goal is not a formula
  1596    of quantifier-free linear arithmetic.
  1597    In ProofGeneral the counter example appears in the trace buffer.
  1598 
  1599  - Knows about div k and mod k where k is a numeral of type nat or int.
  1600 
  1601  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  1602    linear arithmetic fails. This takes account of quantifiers and divisibility.
  1603    Presburger arithmetic can also be called explicitly via presburger(_tac).
  1604 
  1605 * simp's arithmetic capabilities have been enhanced a bit: it now
  1606 takes ~= in premises into account (by performing a case split);
  1607 
  1608 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  1609 are distributed over a sum of terms;
  1610 
  1611 * New tactic "trans_tac" and method "trans" instantiate
  1612 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  1613 "<=", "<" and "=").
  1614 
  1615 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  1616 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  1617 
  1618 * 'typedef' command has new option "open" to suppress the set
  1619 definition;
  1620 
  1621 * functions Min and Max on finite sets have been introduced (theory
  1622 Finite_Set);
  1623 
  1624 * attribute [symmetric] now works for relations as well; it turns
  1625 (x,y) : R^-1 into (y,x) : R, and vice versa;
  1626 
  1627 * induct over a !!-quantified statement (say !!x1..xn):
  1628   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  1629 
  1630 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  1631 %x. None. Warning: empty_def now refers to the previously hidden definition
  1632 of the empty set.
  1633 
  1634 * Algebra: formalization of classical algebra.  Intended as base for
  1635 any algebraic development in Isabelle.  Currently covers group theory
  1636 (up to Sylow's theorem) and ring theory (Universal Property of
  1637 Univariate Polynomials).  Contributions welcome;
  1638 
  1639 * GroupTheory: deleted, since its material has been moved to Algebra;
  1640 
  1641 * Complex: new directory of the complex numbers with numeric constants,
  1642 nonstandard complex numbers, and some complex analysis, standard and
  1643 nonstandard (Jacques Fleuriot);
  1644 
  1645 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  1646 
  1647 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  1648 Fleuriot);
  1649 
  1650 * Real/HahnBanach: updated and adapted to locales;
  1651 
  1652 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  1653 Gray and Kramer);
  1654 
  1655 * UNITY: added the Meier-Sanders theory of progress sets;
  1656 
  1657 * MicroJava: bytecode verifier and lightweight bytecode verifier
  1658 as abstract algorithms, instantiated to the JVM;
  1659 
  1660 * Bali: Java source language formalization. Type system, operational
  1661 semantics, axiomatic semantics. Supported language features:
  1662 classes, interfaces, objects,virtual methods, static methods,
  1663 static/instance fields, arrays, access modifiers, definite
  1664 assignment, exceptions.
  1665 
  1666 
  1667 *** ZF ***
  1668 
  1669 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  1670 universe, etc.);
  1671 
  1672 * Main ZF: virtually all theories converted to new-style format;
  1673 
  1674 
  1675 *** ML ***
  1676 
  1677 * Pure: Tactic.prove provides sane interface for internal proofs;
  1678 omits the infamous "standard" operation, so this is more appropriate
  1679 than prove_goalw_cterm in many situations (e.g. in simprocs);
  1680 
  1681 * Pure: improved error reporting of simprocs;
  1682 
  1683 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  1684 up simprocs;
  1685 
  1686 
  1687 *** Document preparation ***
  1688 
  1689 * uses \par instead of \\ for line breaks in theory text. This may
  1690 shift some page breaks in large documents. To get the old behaviour
  1691 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  1692 
  1693 * minimized dependencies of isabelle.sty and isabellesym.sty on
  1694 other packages
  1695 
  1696 * \<euro> now needs package babel/greek instead of marvosym (which
  1697 broke \Rightarrow)
  1698 
  1699 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  1700 textcomp package)
  1701 
  1702 
  1703 
  1704 New in Isabelle2002 (March 2002)
  1705 --------------------------------
  1706 
  1707 *** Document preparation ***
  1708 
  1709 * greatly simplified document preparation setup, including more
  1710 graceful interpretation of isatool usedir -i/-d/-D options, and more
  1711 instructive isatool mkdir; users should basically be able to get
  1712 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  1713 users may run a separate document processing stage manually like this:
  1714 "isatool usedir -D output HOL Test && isatool document Test/output";
  1715 
  1716 * theory dependency graph may now be incorporated into documents;
  1717 isatool usedir -g true will produce session_graph.eps/.pdf for use
  1718 with \includegraphics of LaTeX;
  1719 
  1720 * proper spacing of consecutive markup elements, especially text
  1721 blocks after section headings;
  1722 
  1723 * support bold style (for single symbols only), input syntax is like
  1724 this: "\<^bold>\<alpha>" or "\<^bold>A";
  1725 
  1726 * \<bullet> is now output as bold \cdot by default, which looks much
  1727 better in printed text;
  1728 
  1729 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  1730 note that these symbols are currently unavailable in Proof General /
  1731 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  1732 
  1733 * isatool latex no longer depends on changed TEXINPUTS, instead
  1734 isatool document copies the Isabelle style files to the target
  1735 location;
  1736 
  1737 
  1738 *** Isar ***
  1739 
  1740 * Pure/Provers: improved proof by cases and induction;
  1741   - 'case' command admits impromptu naming of parameters (such as
  1742     "case (Suc n)");
  1743   - 'induct' method divinates rule instantiation from the inductive
  1744     claim; no longer requires excessive ?P bindings for proper
  1745     instantiation of cases;
  1746   - 'induct' method properly enumerates all possibilities of set/type
  1747     rules; as a consequence facts may be also passed through *type*
  1748     rules without further ado;
  1749   - 'induct' method now derives symbolic cases from the *rulified*
  1750     rule (before it used to rulify cases stemming from the internal
  1751     atomized version); this means that the context of a non-atomic
  1752     statement becomes is included in the hypothesis, avoiding the
  1753     slightly cumbersome show "PROP ?case" form;
  1754   - 'induct' may now use elim-style induction rules without chaining
  1755     facts, using ``missing'' premises from the goal state; this allows
  1756     rules stemming from inductive sets to be applied in unstructured
  1757     scripts, while still benefitting from proper handling of non-atomic
  1758     statements; NB: major inductive premises need to be put first, all
  1759     the rest of the goal is passed through the induction;
  1760   - 'induct' proper support for mutual induction involving non-atomic
  1761     rule statements (uses the new concept of simultaneous goals, see
  1762     below);
  1763   - append all possible rule selections, but only use the first
  1764     success (no backtracking);
  1765   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  1766   - undeclared rule case names default to numbers 1, 2, 3, ...;
  1767   - added 'print_induct_rules' (covered by help item in recent Proof
  1768     General versions);
  1769   - moved induct/cases attributes to Pure, methods to Provers;
  1770   - generic method setup instantiated for FOL and HOL;
  1771 
  1772 * Pure: support multiple simultaneous goal statements, for example
  1773 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  1774 meta-level mechanism, this acts as if several individual goals had
  1775 been stated separately; in particular common proof methods need to be
  1776 repeated in order to cover all claims; note that a single elimination
  1777 step is *not* sufficient to establish the two conjunctions, so this
  1778 fails:
  1779 
  1780   assume "A & B" then have A and B ..   (*".." fails*)
  1781 
  1782 better use "obtain" in situations as above; alternative refer to
  1783 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  1784 
  1785 * Pure: proper integration with ``locales''; unlike the original
  1786 version by Florian Kammller, Isar locales package high-level proof
  1787 contexts rather than raw logical ones (e.g. we admit to include
  1788 attributes everywhere); operations on locales include merge and
  1789 rename; support for implicit arguments (``structures''); simultaneous
  1790 type-inference over imports and text; see also HOL/ex/Locales.thy for
  1791 some examples;
  1792 
  1793 * Pure: the following commands have been ``localized'', supporting a
  1794 target locale specification "(in name)": 'lemma', 'theorem',
  1795 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  1796 stored both within the locale and at the theory level (exported and
  1797 qualified by the locale name);
  1798 
  1799 * Pure: theory goals may now be specified in ``long'' form, with
  1800 ad-hoc contexts consisting of arbitrary locale elements. for example
  1801 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  1802 definitions may be given, too); the result is a meta-level rule with
  1803 the context elements being discharged in the obvious way;
  1804 
  1805 * Pure: new proof command 'using' allows to augment currently used
  1806 facts after a goal statement ('using' is syntactically analogous to
  1807 'apply', but acts on the goal's facts only); this allows chained facts
  1808 to be separated into parts given before and after a claim, as in
  1809 ``from a and b have C using d and e <proof>'';
  1810 
  1811 * Pure: renamed "antecedent" case to "rule_context";
  1812 
  1813 * Pure: new 'judgment' command records explicit information about the
  1814 object-logic embedding (used by several tools internally); no longer
  1815 use hard-wired "Trueprop";
  1816 
  1817 * Pure: added 'corollary' command;
  1818 
  1819 * Pure: fixed 'token_translation' command;
  1820 
  1821 * Pure: removed obsolete 'exported' attribute;
  1822 
  1823 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  1824 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  1825 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  1826 
  1827 * Pure: method 'atomize' presents local goal premises as object-level
  1828 statements (atomic meta-level propositions); setup controlled via
  1829 rewrite rules declarations of 'atomize' attribute; example
  1830 application: 'induct' method with proper rule statements in improper
  1831 proof *scripts*;
  1832 
  1833 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  1834 now consider the syntactic context of assumptions, giving a better
  1835 chance to get type-inference of the arguments right (this is
  1836 especially important for locales);
  1837 
  1838 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1839 mode;
  1840 
  1841 * Pure/obtain: the formal conclusion "thesis", being marked as
  1842 ``internal'', may no longer be reference directly in the text;
  1843 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1844 situations;
  1845 
  1846 * Pure: generic 'sym' attribute which declares a rule both as pure
  1847 'elim?' and for the 'symmetric' operation;
  1848 
  1849 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1850 text; the fixed correlation with particular command syntax has been
  1851 discontinued;
  1852 
  1853 * Pure: new method 'rules' is particularly well-suited for proof
  1854 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1855 but often produces more compact proof terms with less detours;
  1856 
  1857 * Pure/Provers/classical: simplified integration with pure rule
  1858 attributes and methods; the classical "intro?/elim?/dest?"
  1859 declarations coincide with the pure ones; the "rule" method no longer
  1860 includes classically swapped intros; "intro" and "elim" methods no
  1861 longer pick rules from the context; also got rid of ML declarations
  1862 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1863 INCOMPATIBILITY;
  1864 
  1865 * Provers/classical: attribute 'swapped' produces classical inversions
  1866 of introduction rules;
  1867 
  1868 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1869 rules instead of full simplifier context; 'iff' attribute handles
  1870 conditional rules;
  1871 
  1872 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1873 
  1874 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1875 "(permissive)" option to recover old behavior;
  1876 
  1877 * HOL: 'inductive' no longer features separate (collective) attributes
  1878 for 'intros' (was found too confusing);
  1879 
  1880 * HOL: properly declared induction rules less_induct and
  1881 wf_induct_rule;
  1882 
  1883 
  1884 *** HOL ***
  1885 
  1886 * HOL: moved over to sane numeral syntax; the new policy is as
  1887 follows:
  1888 
  1889   - 0 and 1 are polymorphic constants, which are defined on any
  1890   numeric type (nat, int, real etc.);
  1891 
  1892   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1893   binary representation internally;
  1894 
  1895   - type nat has special constructor Suc, and generally prefers Suc 0
  1896   over 1::nat and Suc (Suc 0) over 2::nat;
  1897 
  1898 This change may cause significant problems of INCOMPATIBILITY; here
  1899 are some hints on converting existing sources:
  1900 
  1901   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1902   entities, so expressions involving "-" (unary or binary minus) need
  1903   to be spaced properly;
  1904 
  1905   - existing occurrences of "1" may need to be constraint "1::nat" or
  1906   even replaced by Suc 0; similar for old "2";
  1907 
  1908   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1909 
  1910   - remove all special provisions on numerals in proofs;
  1911 
  1912 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1913 representation (depends on bin_arith_simps in the default context);
  1914 
  1915 * HOL: symbolic syntax for x^2 (numeral 2);
  1916 
  1917 * HOL: the class of all HOL types is now called "type" rather than
  1918 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1919 in axclass/classes, instance/arities, and (usually rare) occurrences
  1920 in typings (of consts etc.); internally the class is called
  1921 "HOL.type", ML programs should refer to HOLogic.typeS;
  1922 
  1923 * HOL/record package improvements:
  1924   - new derived operations "fields" to build a partial record section,
  1925     "extend" to promote a fixed record to a record scheme, and
  1926     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1927     declared as simp by default;
  1928   - shared operations ("more", "fields", etc.) now need to be always
  1929     qualified) --- potential INCOMPATIBILITY;
  1930   - removed "make_scheme" operations (use "make" with "extend") --
  1931     INCOMPATIBILITY;
  1932   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1933   - provides cases/induct rules for use with corresponding Isar
  1934     methods (for concrete records, record schemes, concrete more
  1935     parts, and schematic more parts -- in that order);
  1936   - internal definitions directly based on a light-weight abstract
  1937     theory of product types over typedef rather than datatype;
  1938 
  1939 * HOL: generic code generator for generating executable ML code from
  1940 specifications; specific support for HOL constructs such as inductive
  1941 datatypes and sets, as well as recursive functions; can be invoked
  1942 via 'generate_code' theory section;
  1943 
  1944 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1945 
  1946 * HOL: consolidated and renamed several theories.  In particular:
  1947         Ord.thy has been absorbed into HOL.thy
  1948         String.thy has been absorbed into List.thy
  1949 
  1950 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1951 (beware of argument permutation!);
  1952 
  1953 * HOL: linorder_less_split superseded by linorder_cases;
  1954 
  1955 * HOL/List: "nodups" renamed to "distinct";
  1956 
  1957 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1958 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1959   - Ex_def has changed, now need to use some_eq_ex
  1960 
  1961 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1962 in this (rare) case use:
  1963 
  1964   delSWrapper "split_all_tac"
  1965   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1966 
  1967 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1968 MAY FAIL;
  1969 
  1970 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1971 Isabelle's type classes, ^ on functions and relations has too general
  1972 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1973 necessary to attach explicit type constraints;
  1974 
  1975 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1976 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1977 renamed accordingly (eg "compI" -> "rel_compI").
  1978 
  1979 * HOL: syntax translations now work properly with numerals and records
  1980 expressions;
  1981 
  1982 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1983 of "lam" -- INCOMPATIBILITY;
  1984 
  1985 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1986 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1987 renamed "Product_Type.unit";
  1988 
  1989 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1990 
  1991 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1992 the "cases" method);
  1993 
  1994 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1995 Florian Kammller);
  1996 
  1997 * HOL/IMP: updated and converted to new-style theory format; several
  1998 parts turned into readable document, with proper Isar proof texts and
  1999 some explanations (by Gerwin Klein);
  2000 
  2001 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  2002 
  2003 * HOL-Hyperreal is now a logic image;
  2004 
  2005 
  2006 *** HOLCF ***
  2007 
  2008 * Isar: consts/constdefs supports mixfix syntax for continuous
  2009 operations;
  2010 
  2011 * Isar: domain package adapted to new-style theory format, e.g. see
  2012 HOLCF/ex/Dnat.thy;
  2013 
  2014 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  2015 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  2016 lift.induct_tac, always use UU instead of Undef;
  2017 
  2018 * HOLCF/IMP: updated and converted to new-style theory;
  2019 
  2020 
  2021 *** ZF ***
  2022 
  2023 * Isar: proper integration of logic-specific tools and packages,
  2024 including theory commands '(co)inductive', '(co)datatype',
  2025 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  2026 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  2027 
  2028 * theory Main no longer includes AC; for the Axiom of Choice, base
  2029 your theory on Main_ZFC;
  2030 
  2031 * the integer library now covers quotients and remainders, with many
  2032 laws relating division to addition, multiplication, etc.;
  2033 
  2034 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  2035 typeless version of the formalism;
  2036 
  2037 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  2038 format;
  2039 
  2040 * ZF/Induct: new directory for examples of inductive definitions,
  2041 including theory Multiset for multiset orderings; converted to
  2042 new-style theory format;
  2043 
  2044 * ZF: many new theorems about lists, ordinals, etc.;
  2045 
  2046 
  2047 *** General ***
  2048 
  2049 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  2050 variable proof controls level of detail: 0 = no proofs (only oracle
  2051 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  2052 also ref manual for further ML interfaces;
  2053 
  2054 * Pure/axclass: removed obsolete ML interface
  2055 goal_subclass/goal_arity;
  2056 
  2057 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  2058 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  2059 separate tokens, so expressions involving minus need to be spaced
  2060 properly;
  2061 
  2062 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  2063 rather than "infixl" or "infixr";
  2064 
  2065 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  2066 sort constraint specifications in type inference; e.g. "x::_::foo"
  2067 ensures that the type of "x" is of sort "foo" (but not necessarily a
  2068 type variable);
  2069 
  2070 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  2071 control output of nested => (types); the default behavior is
  2072 "type_brackets";
  2073 
  2074 * Pure/syntax: builtin parse translation for "_constify" turns valued
  2075 tokens into AST constants;
  2076 
  2077 * Pure/syntax: prefer later declarations of translations and print
  2078 translation functions; potential INCOMPATIBILITY: need to reverse
  2079 multiple declarations for same syntax element constant;
  2080 
  2081 * Pure/show_hyps reset by default (in accordance to existing Isar
  2082 practice);
  2083 
  2084 * Provers/classical: renamed addaltern to addafter, addSaltern to
  2085 addSafter;
  2086 
  2087 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  2088 as well;
  2089 
  2090 * system: tested support for MacOS X; should be able to get Isabelle +
  2091 Proof General to work in a plain Terminal after installing Poly/ML
  2092 (e.g. from the Isabelle distribution area) and GNU bash alone
  2093 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  2094 support requires further installations, e.g. from
  2095 http://fink.sourceforge.net/);
  2096 
  2097 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  2098 
  2099 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  2100 of 40 MB), cf. ML_OPTIONS;
  2101 
  2102 * system: Proof General keywords specification is now part of the
  2103 Isabelle distribution (see etc/isar-keywords.el);
  2104 
  2105 * system: support for persistent Proof General sessions (refrain from
  2106 outdating all loaded theories on startup); user may create writable
  2107 logic images like this: ``isabelle -q HOL Test'';
  2108 
  2109 * system: smart selection of Isabelle process versus Isabelle
  2110 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  2111 run both "isabelle" and "Isabelle" even if file names are badly
  2112 damaged (executable inspects the case of the first letter of its own
  2113 name); added separate "isabelle-process" and "isabelle-interface";
  2114 
  2115 * system: refrain from any attempt at filtering input streams; no
  2116 longer support ``8bit'' encoding of old isabelle font, instead proper
  2117 iso-latin characters may now be used; the related isatools
  2118 "symbolinput" and "nonascii" have disappeared as well;
  2119 
  2120 * system: removed old "xterm" interface (the print modes "xterm" and
  2121 "xterm_color" are still available for direct use in a suitable
  2122 terminal);
  2123 
  2124 
  2125 
  2126 New in Isabelle99-2 (February 2001)
  2127 -----------------------------------
  2128 
  2129 *** Overview of INCOMPATIBILITIES ***
  2130 
  2131 * HOL: please note that theories in the Library and elsewhere often use the
  2132 new-style (Isar) format; to refer to their theorems in an ML script you must
  2133 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  2134 
  2135 * HOL: inductive package no longer splits induction rule aggressively,
  2136 but only as far as specified by the introductions given; the old
  2137 format may be recovered via ML function complete_split_rule or attribute
  2138 'split_rule (complete)';
  2139 
  2140 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  2141 gfp_Tarski to gfp_unfold;
  2142 
  2143 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  2144 
  2145 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  2146 relation); infix "^^" has been renamed "``"; infix "``" has been
  2147 renamed "`"; "univalent" has been renamed "single_valued";
  2148 
  2149 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  2150 operation;
  2151 
  2152 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  2153 
  2154 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  2155 
  2156 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  2157 consequence, it is no longer monotonic wrt. the local goal context
  2158 (which is now passed through the inductive cases);
  2159 
  2160 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  2161 \<gg> to \<ggreater>;
  2162 
  2163 
  2164 *** Document preparation ***
  2165 
  2166 * \isabellestyle{NAME} selects version of Isabelle output (currently
  2167 available: are "it" for near math-mode best-style output, "sl" for
  2168 slanted text style, and "tt" for plain type-writer; if no
  2169 \isabellestyle command is given, output is according to slanted
  2170 type-writer);
  2171 
  2172 * support sub/super scripts (for single symbols only), input syntax is
  2173 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  2174 
  2175 * some more standard symbols; see Appendix A of the system manual for
  2176 the complete list of symbols defined in isabellesym.sty;
  2177 
  2178 * improved isabelle style files; more abstract symbol implementation
  2179 (should now use \isamath{...} and \isatext{...} in custom symbol
  2180 definitions);
  2181 
  2182 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  2183 state; Note that presentation of goal states does not conform to
  2184 actual human-readable proof documents.  Please do not include goal
  2185 states into document output unless you really know what you are doing!
  2186 
  2187 * proper indentation of antiquoted output with proportional LaTeX
  2188 fonts;
  2189 
  2190 * no_document ML operator temporarily disables LaTeX document
  2191 generation;
  2192 
  2193 * isatool unsymbolize tunes sources for plain ASCII communication;
  2194 
  2195 
  2196 *** Isar ***
  2197 
  2198 * Pure: Isar now suffers initial goal statements to contain unbound
  2199 schematic variables (this does not conform to actual readable proof
  2200 documents, due to unpredictable outcome and non-compositional proof
  2201 checking); users who know what they are doing may use schematic goals
  2202 for Prolog-style synthesis of proven results;
  2203 
  2204 * Pure: assumption method (an implicit finishing) now handles actual
  2205 rules as well;
  2206 
  2207 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  2208 initial goal, declare "that" only as Pure intro (only for single
  2209 steps); the "that" rule assumption may now be involved in implicit
  2210 finishing, thus ".." becomes a feasible for trivial obtains;
  2211 
  2212 * Pure: default proof step now includes 'intro_classes'; thus trivial
  2213 instance proofs may be performed by "..";
  2214 
  2215 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  2216 statements as well;
  2217 
  2218 * Pure: more robust selection of calculational rules;
  2219 
  2220 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  2221 rule (as well as the assumption rule);
  2222 
  2223 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  2224 lemmas, using the graph browser tool;
  2225 
  2226 * Pure: predict failure of "show" in interactive mode;
  2227 
  2228 * Pure: 'thms_containing' now takes actual terms as arguments;
  2229 
  2230 * HOL: improved method 'induct' --- now handles non-atomic goals
  2231 (potential INCOMPATIBILITY); tuned error handling;
  2232 
  2233 * HOL: cases and induct rules now provide explicit hints about the
  2234 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  2235 any remaining facts are inserted into the goal verbatim;
  2236 
  2237 * HOL: local contexts (aka cases) may now contain term bindings as
  2238 well; the 'cases' and 'induct' methods new provide a ?case binding for
  2239 the result to be shown in each case;
  2240 
  2241 * HOL: added 'recdef_tc' command;
  2242 
  2243 * isatool convert assists in eliminating legacy ML scripts;
  2244 
  2245 
  2246 *** HOL ***
  2247 
  2248 * HOL/Library: a collection of generic theories to be used together
  2249 with main HOL; the theory loader path already includes this directory
  2250 by default; the following existing theories have been moved here:
  2251 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  2252 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  2253 
  2254 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  2255 modelling and verification task performed in Isabelle/HOL +
  2256 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  2257 
  2258 * HOL/Algebra: special summation operator SUM no longer exists, it has
  2259 been replaced by setsum; infix 'assoc' now has priority 50 (like
  2260 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  2261 'domain', this makes the theory consistent with mathematical
  2262 literature;
  2263 
  2264 * HOL basics: added overloaded operations "inverse" and "divide"
  2265 (infix "/"), syntax for generic "abs" operation, generic summation
  2266 operator \<Sum>;
  2267 
  2268 * HOL/typedef: simplified package, provide more useful rules (see also
  2269 HOL/subset.thy);
  2270 
  2271 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  2272 now expressed as a proper nested rule (old-style tactic scripts may
  2273 require atomize_strip_tac to cope with non-atomic premises);
  2274 
  2275 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  2276 to "split_conv" (old name still available for compatibility);
  2277 
  2278 * HOL: improved concrete syntax for strings (e.g. allows translation
  2279 rules with string literals);
  2280 
  2281 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  2282  and Fleuriot's mechanization of analysis, including the transcendental
  2283  functions for the reals;
  2284 
  2285 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  2286 
  2287 
  2288 *** CTT ***
  2289 
  2290 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  2291 "lam" is displayed as TWO lambda-symbols
  2292 
  2293 * CTT: theory Main now available, containing everything (that is, Bool
  2294 and Arith);
  2295 
  2296 
  2297 *** General ***
  2298 
  2299 * Pure: the Simplifier has been implemented properly as a derived rule
  2300 outside of the actual kernel (at last!); the overall performance
  2301 penalty in practical applications is about 50%, while reliability of
  2302 the Isabelle inference kernel has been greatly improved;
  2303 
  2304 * print modes "brackets" and "no_brackets" control output of nested =>
  2305 (types) and ==> (props); the default behaviour is "brackets";
  2306 
  2307 * Provers: fast_tac (and friends) now handle actual object-logic rules
  2308 as assumptions as well;
  2309 
  2310 * system: support Poly/ML 4.0;
  2311 
  2312 * system: isatool install handles KDE version 1 or 2;
  2313 
  2314 
  2315 
  2316 New in Isabelle99-1 (October 2000)
  2317 ----------------------------------
  2318 
  2319 *** Overview of INCOMPATIBILITIES ***
  2320 
  2321 * HOL: simplification of natural numbers is much changed; to partly
  2322 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  2323 issue the following ML commands:
  2324 
  2325   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  2326   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  2327 
  2328 * HOL: simplification no longer dives into case-expressions; this is
  2329 controlled by "t.weak_case_cong" for each datatype t;
  2330 
  2331 * HOL: nat_less_induct renamed to less_induct;
  2332 
  2333 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  2334 fixsome to patch .thy and .ML sources automatically;
  2335 
  2336   select_equality  -> some_equality
  2337   select_eq_Ex     -> some_eq_ex
  2338   selectI2EX       -> someI2_ex
  2339   selectI2         -> someI2
  2340   selectI          -> someI
  2341   select1_equality -> some1_equality
  2342   Eps_sym_eq       -> some_sym_eq_trivial
  2343   Eps_eq           -> some_eq_trivial
  2344 
  2345 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  2346 
  2347 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  2348 instead);
  2349 
  2350 * HOL: the recursion equations generated by 'recdef' are now called
  2351 f.simps instead of f.rules;
  2352 
  2353 * HOL: qed_spec_mp now also handles bounded ALL as well;
  2354 
  2355 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  2356 sometimes be needed;
  2357 
  2358 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  2359 
  2360 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  2361 
  2362 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  2363 product is now "<*>" instead of "Times"; the lexicographic product is
  2364 now "<*lex*>" instead of "**";
  2365 
  2366 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  2367 of main HOL, but was unused); better use HOL's datatype package;
  2368 
  2369 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  2370 the old syntax may be recovered as follows:
  2371 
  2372   syntax (symbols)
  2373     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  2374       (infixl "\\<oplus>" 100)
  2375 
  2376 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2377 
  2378 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  2379 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  2380 internally;
  2381 
  2382 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  2383 changed from A/r to A//r;
  2384 
  2385 * ZF: new treatment of arithmetic (nat & int) may break some old
  2386 proofs;
  2387 
  2388 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  2389 rulify -> rule_format, elimify -> elim_format, ...);
  2390 
  2391 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2392 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  2393 should have to change intro!! to intro? only); replaced "delrule" by
  2394 "rule del";
  2395 
  2396 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  2397 
  2398 * Provers: strengthened force_tac by using new first_best_tac;
  2399 
  2400 * LaTeX document preparation: several changes of isabelle.sty (see
  2401 lib/texinputs);
  2402 
  2403 
  2404 *** Document preparation ***
  2405 
  2406 * formal comments (text blocks etc.) in new-style theories may now
  2407 contain antiquotations of thm/prop/term/typ/text to be presented
  2408 according to latex print mode; concrete syntax is like this:
  2409 @{term[show_types] "f(x) = a + x"};
  2410 
  2411 * isatool mkdir provides easy setup of Isabelle session directories,
  2412 including proper document sources;
  2413 
  2414 * generated LaTeX sources are now deleted after successful run
  2415 (isatool document -c); may retain a copy somewhere else via -D option
  2416 of isatool usedir;
  2417 
  2418 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  2419 style files, achieving self-contained LaTeX sources and simplifying
  2420 LaTeX debugging;
  2421 
  2422 * old-style theories now produce (crude) LaTeX output as well;
  2423 
  2424 * browser info session directories are now self-contained (may be put
  2425 on WWW server seperately); improved graphs of nested sessions; removed
  2426 graph for 'all sessions';
  2427 
  2428 * several improvements in isabelle style files; \isabellestyle{it}
  2429 produces fake math mode output; \isamarkupheader is now \section by
  2430 default; see lib/texinputs/isabelle.sty etc.;
  2431 
  2432 
  2433 *** Isar ***
  2434 
  2435 * Isar/Pure: local results and corresponding term bindings are now
  2436 subject to Hindley-Milner polymorphism (similar to ML); this
  2437 accommodates incremental type-inference very nicely;
  2438 
  2439 * Isar/Pure: new derived language element 'obtain' supports
  2440 generalized existence reasoning;
  2441 
  2442 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  2443 support accumulation of results, without applying any rules yet;
  2444 useful to collect intermediate results without explicit name
  2445 references, and for use with transitivity rules with more than 2
  2446 premises;
  2447 
  2448 * Isar/Pure: scalable support for case-analysis type proofs: new
  2449 'case' language element refers to local contexts symbolically, as
  2450 produced by certain proof methods; internally, case names are attached
  2451 to theorems as "tags";
  2452 
  2453 * Isar/Pure: theory command 'hide' removes declarations from
  2454 class/type/const name spaces;
  2455 
  2456 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  2457 indicate potential overloading;
  2458 
  2459 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  2460 
  2461 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  2462 "{a,b,c}" instead of {a,b,c};
  2463 
  2464 * Isar/Pure now provides its own version of intro/elim/dest
  2465 attributes; useful for building new logics, but beware of confusion
  2466 with the version in Provers/classical;
  2467 
  2468 * Isar/Pure: the local context of (non-atomic) goals is provided via
  2469 case name 'antecedent';
  2470 
  2471 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  2472 to the current context is now done automatically);
  2473 
  2474 * Isar/Pure: theory command 'method_setup' provides a simple interface
  2475 for definining proof methods in ML;
  2476 
  2477 * Isar/Provers: intro/elim/dest attributes changed; renamed
  2478 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  2479 most cases, one should have to change intro!! to intro? only);
  2480 replaced "delrule" by "rule del";
  2481 
  2482 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  2483 'symmetric' attribute (the latter supercedes [RS sym]);
  2484 
  2485 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  2486 method modifier); 'simp' method: 'only:' modifier removes loopers as
  2487 well (including splits);
  2488 
  2489 * Isar/Provers: Simplifier and Classical methods now support all kind
  2490 of modifiers used in the past, including 'cong', 'iff', etc.
  2491 
  2492 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  2493 of Simplifier and Classical reasoner);
  2494 
  2495 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  2496 now support named cases; major packages (inductive, datatype, primrec,
  2497 recdef) support case names and properly name parameters;
  2498 
  2499 * Isar/HOL: new transitivity rules for substitution in inequalities --
  2500 monotonicity conditions are extracted to be proven at end of
  2501 calculations;
  2502 
  2503 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  2504 method anyway;
  2505 
  2506 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  2507 split_if split_if_asm; datatype package provides theorems foo.splits =
  2508 foo.split foo.split_asm for each datatype;
  2509 
  2510 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  2511 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  2512 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  2513 use "(cases (simplified))" method in proper proof texts);
  2514 
  2515 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  2516 
  2517 * Isar: names of theorems etc. may be natural numbers as well;
  2518 
  2519 * Isar: 'pr' command: optional arguments for goals_limit and
  2520 ProofContext.prems_limit; no longer prints theory contexts, but only
  2521 proof states;
  2522 
  2523 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  2524 additional print modes to be specified; e.g. "pr(latex)" will print
  2525 proof state according to the Isabelle LaTeX style;
  2526 
  2527 * Isar: improved support for emulating tactic scripts, including proof
  2528 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  2529 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  2530 (for HOL datatypes);
  2531 
  2532 * Isar: simplified (more robust) goal selection of proof methods: 1st
  2533 goal, all goals, or explicit goal specifier (tactic emulation); thus
  2534 'proof method scripts' have to be in depth-first order;
  2535 
  2536 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  2537 
  2538 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  2539 should instead use individual commands for printing items
  2540 (print_commands, print_methods etc.);
  2541 
  2542 * Isar: added 'nothing' --- the empty list of theorems;
  2543 
  2544 
  2545 *** HOL ***
  2546 
  2547 * HOL/MicroJava: formalization of a fragment of Java, together with a
  2548 corresponding virtual machine and a specification of its bytecode
  2549 verifier and a lightweight bytecode verifier, including proofs of
  2550 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  2551 Cornelia Pusch (see also the homepage of project Bali at
  2552 http://isabelle.in.tum.de/Bali/);
  2553 
  2554 * HOL/Algebra: new theory of rings and univariate polynomials, by
  2555 Clemens Ballarin;
  2556 
  2557 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  2558 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  2559 Rasmussen;
  2560 
  2561 * HOL/Lattice: fundamental concepts of lattice theory and order
  2562 structures, including duals, properties of bounds versus algebraic
  2563 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  2564 Theorem for complete lattices etc.; may also serve as a demonstration
  2565 for abstract algebraic reasoning using axiomatic type classes, and
  2566 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  2567 
  2568 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  2569 von Oheimb;
  2570 
  2571 * HOL/IMPP: extension of IMP with local variables and mutually
  2572 recursive procedures, by David von Oheimb;
  2573 
  2574 * HOL/Lambda: converted into new-style theory and document;
  2575 
  2576 * HOL/ex/Multiquote: example of multiple nested quotations and
  2577 anti-quotations -- basically a generalized version of de-Bruijn
  2578 representation; very useful in avoiding lifting of operations;
  2579 
  2580 * HOL/record: added general record equality rule to simpset; fixed
  2581 select-update simplification procedure to handle extended records as
  2582 well; admit "r" as field name;
  2583 
  2584 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  2585 other numeric types and also as the identity of groups, rings, etc.;
  2586 
  2587 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  2588 Types nat and int belong to this axclass;
  2589 
  2590 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  2591    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  2592    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  2593   two terms #m*u and #n*u are replaced by #(m+n)*u
  2594     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  2595   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  2596     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  2597 
  2598 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  2599 powerful prover for predicate logic but knows nothing of clasets; see
  2600 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  2601 
  2602 * HOL: new version of "case_tac" subsumes both boolean case split and
  2603 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  2604 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  2605 
  2606 * HOL: simplification no longer dives into case-expressions: only the
  2607 selector expression is simplified, but not the remaining arms; to
  2608 enable full simplification of case-expressions for datatype t, you may
  2609 remove t.weak_case_cong from the simpset, either globally (Delcongs
  2610 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  2611 
  2612 * HOL/recdef: the recursion equations generated by 'recdef' for
  2613 function 'f' are now called f.simps instead of f.rules; if all
  2614 termination conditions are proved automatically, these simplification
  2615 rules are added to the simpset, as in primrec; rules may be named
  2616 individually as well, resulting in a separate list of theorems for
  2617 each equation;
  2618 
  2619 * HOL/While is a new theory that provides a while-combinator. It
  2620 permits the definition of tail-recursive functions without the
  2621 provision of a termination measure. The latter is necessary once the
  2622 invariant proof rule for while is applied.
  2623 
  2624 * HOL: new (overloaded) notation for the set of elements below/above
  2625 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  2626 
  2627 * HOL: theorems impI, allI, ballI bound as "strip";
  2628 
  2629 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  2630 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  2631 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  2632 
  2633 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  2634 
  2635 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  2636 main HOL, but was unused);
  2637 
  2638 * HOL: fewer consts declared as global (e.g. have to refer to
  2639 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  2640 
  2641 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  2642 in case of overlap with user translations (e.g. judgements over
  2643 tuples); (note that the underlying logical represenation is still
  2644 bogus);
  2645 
  2646 
  2647 *** ZF ***
  2648 
  2649 * ZF: simplification automatically cancels common terms in arithmetic
  2650 expressions over nat and int;
  2651 
  2652 * ZF: new treatment of nat to minimize type-checking: all operators
  2653 coerce their operands to a natural number using the function natify,
  2654 making the algebraic laws unconditional;
  2655 
  2656 * ZF: as above, for int: operators coerce their operands to an integer
  2657 using the function intify;
  2658 
  2659 * ZF: the integer library now contains many of the usual laws for the
  2660 orderings, including $<=, and monotonicity laws for $+ and $*;
  2661 
  2662 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  2663 simplification;
  2664 
  2665 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  2666 to the simplifier and classical reasoner simultaneously;
  2667 
  2668 
  2669 *** General ***
  2670 
  2671 * Provers: blast_tac now handles actual object-logic rules as
  2672 assumptions; note that auto_tac uses blast_tac internally as well;
  2673 
  2674 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  2675 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  2676 
  2677 * Provers: delrules now handles destruct rules as well (no longer need
  2678 explicit make_elim);
  2679 
  2680 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  2681   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2682 use instead the strong form,
  2683   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  2684 in HOL, FOL and ZF the function cla_make_elim will create such rules
  2685 from destruct-rules;
  2686 
  2687 * Provers: Simplifier.easy_setup provides a fast path to basic
  2688 Simplifier setup for new object-logics;
  2689 
  2690 * Pure: AST translation rules no longer require constant head on LHS;
  2691 
  2692 * Pure: improved name spaces: ambiguous output is qualified; support
  2693 for hiding of names;
  2694 
  2695 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  2696 XSYMBOL_HOME; no longer need to do manual configuration in most
  2697 situations;
  2698 
  2699 * system: compression of ML heaps images may now be controlled via -c
  2700 option of isabelle and isatool usedir (currently only observed by
  2701 Poly/ML);
  2702 
  2703 * system: isatool installfonts may handle X-Symbol fonts as well (very
  2704 useful for remote X11);
  2705 
  2706 * system: provide TAGS file for Isabelle sources;
  2707 
  2708 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  2709 order;
  2710 
  2711 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  2712 timing flag supersedes proof_timing and Toplevel.trace;
  2713 
  2714 * ML: new combinators |>> and |>>> for incremental transformations
  2715 with secondary results (e.g. certain theory extensions):
  2716 
  2717 * ML: PureThy.add_defs gets additional argument to indicate potential
  2718 overloading (usually false);
  2719 
  2720 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  2721 results;
  2722 
  2723 
  2724 
  2725 New in Isabelle99 (October 1999)
  2726 --------------------------------
  2727 
  2728 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2729 
  2730 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  2731 are no longer simplified.  (This allows the simplifier to unfold recursive
  2732 functional programs.)  To restore the old behaviour, declare
  2733 
  2734     Delcongs [if_weak_cong];
  2735 
  2736 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  2737 complement;
  2738 
  2739 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  2740 
  2741 * HOL/datatype: mutual_induct_tac no longer exists --
  2742   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  2743 
  2744 * HOL/typedef: fixed type inference for representing set; type
  2745 arguments now have to occur explicitly on the rhs as type constraints;
  2746 
  2747 * ZF: The con_defs part of an inductive definition may no longer refer
  2748 to constants declared in the same theory;
  2749 
  2750 * HOL, ZF: the function mk_cases, generated by the inductive
  2751 definition package, has lost an argument.  To simplify its result, it
  2752 uses the default simpset instead of a supplied list of theorems.
  2753 
  2754 * HOL/List: the constructors of type list are now Nil and Cons;
  2755 
  2756 * Simplifier: the type of the infix ML functions
  2757         setSSolver addSSolver setSolver addSolver
  2758 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  2759 for packaging solvers. A solver is created via
  2760         mk_solver: string -> (thm list -> int -> tactic) -> solver
  2761 where the string argument is only a comment.
  2762 
  2763 
  2764 *** Proof tools ***
  2765 
  2766 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  2767 decision procedure for linear arithmetic. Currently it is used for
  2768 types `nat', `int', and `real' in HOL (see below); it can, should and
  2769 will be instantiated for other types and logics as well.
  2770 
  2771 * The simplifier now accepts rewrite rules with flexible heads, eg
  2772      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  2773   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  2774   matching.
  2775 
  2776 
  2777 *** General ***
  2778 
  2779 * New Isabelle/Isar subsystem provides an alternative to traditional
  2780 tactical theorem proving; together with the ProofGeneral/isar user
  2781 interface it offers an interactive environment for developing human
  2782 readable proof documents (Isar == Intelligible semi-automated
  2783 reasoning); for further information see isatool doc isar-ref,
  2784 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  2785 
  2786 * improved and simplified presentation of theories: better HTML markup
  2787 (including colors), graph views in several sizes; isatool usedir now
  2788 provides a proper interface for user theories (via -P option); actual
  2789 document preparation based on (PDF)LaTeX is available as well (for
  2790 new-style theories only); see isatool doc system for more information;
  2791 
  2792 * native support for Proof General, both for classic Isabelle and
  2793 Isabelle/Isar;
  2794 
  2795 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  2796 using the graph browser tool;
  2797 
  2798 * Isabelle manuals now also available as PDF;
  2799 
  2800 * theory loader rewritten from scratch (may not be fully
  2801 bug-compatible); old loadpath variable has been replaced by show_path,
  2802 add_path, del_path, reset_path functions; new operations such as
  2803 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  2804 isatool doc ref);
  2805 
  2806 * improved isatool install: option -k creates KDE application icon,
  2807 option -p DIR installs standalone binaries;
  2808 
  2809 * added ML_PLATFORM setting (useful for cross-platform installations);
  2810 more robust handling of platform specific ML images for SML/NJ;
  2811 
  2812 * the settings environment is now statically scoped, i.e. it is never
  2813 created again in sub-processes invoked from isabelle, isatool, or
  2814 Isabelle;
  2815 
  2816 * path element specification '~~' refers to '$ISABELLE_HOME';
  2817 
  2818 * in locales, the "assumes" and "defines" parts may be omitted if
  2819 empty;
  2820 
  2821 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  2822 long arrows);
  2823 
  2824 * new print_mode "HTML";
  2825 
  2826 * new flag show_tags controls display of tags of theorems (which are
  2827 basically just comments that may be attached by some tools);
  2828 
  2829 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  2830 mode and goal output format:
  2831 
  2832 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  2833 244c244
  2834 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  2835 ---
  2836 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  2837 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  2838 181c181
  2839 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2840 ---
  2841 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2842 
  2843 * function bind_thms stores lists of theorems (cf. bind_thm);
  2844 
  2845 * new shorthand tactics ftac, eatac, datac, fatac;
  2846 
  2847 * qed (and friends) now accept "" as result name; in that case the
  2848 theorem is not stored, but proper checks and presentation of the
  2849 result still apply;
  2850 
  2851 * theorem database now also indexes constants "Trueprop", "all",
  2852 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2853 
  2854 
  2855 *** HOL ***
  2856 
  2857 ** HOL arithmetic **
  2858 
  2859 * There are now decision procedures for linear arithmetic over nat and
  2860 int:
  2861 
  2862 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2863 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2864 are treated as atomic; subformulae not involving type `nat' or `int'
  2865 are ignored; quantified subformulae are ignored unless they are
  2866 positive universal or negative existential. The tactic has to be
  2867 invoked by hand and can be a little bit slow. In particular, the
  2868 running time is exponential in the number of occurrences of `min' and
  2869 `max', and `-' on `nat'.
  2870 
  2871 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2872 (negated) (in)equalities among the premises and the conclusion into
  2873 account (i.e. no compound formulae) and does not know about `min' and
  2874 `max', and `-' on `nat'. It is fast and is used automatically by the
  2875 simplifier.
  2876 
  2877 NB: At the moment, these decision procedures do not cope with mixed
  2878 nat/int formulae where the two parts interact, such as `m < n ==>
  2879 int(m) < int(n)'.
  2880 
  2881 * HOL/Numeral provides a generic theory of numerals (encoded
  2882 efficiently as bit strings); setup for types nat/int/real is in place;
  2883 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2884 int, existing theories and proof scripts may require a few additional
  2885 type constraints;
  2886 
  2887 * integer division and remainder can now be performed on constant
  2888 arguments;
  2889 
  2890 * many properties of integer multiplication, division and remainder
  2891 are now available;
  2892 
  2893 * An interface to the Stanford Validity Checker (SVC) is available through the
  2894 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2895 are proved automatically.  SVC must be installed separately, and its results
  2896 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2897 invocation of the underlying oracle).  For SVC see
  2898   http://verify.stanford.edu/SVC
  2899 
  2900 * IsaMakefile: the HOL-Real target now builds an actual image;
  2901 
  2902 
  2903 ** HOL misc **
  2904 
  2905 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2906 (in Isabelle/Isar) -- by Gertrud Bauer;
  2907 
  2908 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2909 analysis for assembly languages with subtypes;
  2910 
  2911 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2912 -- avoids syntactic ambiguities and treats state, transition, and
  2913 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2914 changed syntax and (many) tactics;
  2915 
  2916 * HOL/inductive: Now also handles more general introduction rules such
  2917   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2918   theorems are now maintained within the theory (maintained via the
  2919   "mono" attribute);
  2920 
  2921 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2922   (using function types) such as
  2923 
  2924   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2925 
  2926 * HOL/record: record_simproc (part of the default simpset) takes care
  2927 of selectors applied to updated records; record_split_tac is no longer
  2928 part of the default claset; update_defs may now be removed from the
  2929 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2930 
  2931   claset_ref () := claset() addSWrapper record_split_wrapper;
  2932   Delsimprocs [record_simproc]
  2933 
  2934 * HOL/typedef: fixed type inference for representing set; type
  2935 arguments now have to occur explicitly on the rhs as type constraints;
  2936 
  2937 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2938 names rather than an ML expression;
  2939 
  2940 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2941 supplied later.  Program schemes can be defined, such as
  2942     "While B C s = (if B s then While B C (C s) else s)"
  2943 where the well-founded relation can be chosen after B and C have been given.
  2944 
  2945 * HOL/List: the constructors of type list are now Nil and Cons;
  2946 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2947 course, ML tools referring to List.list.op # etc. have to be adapted;
  2948 
  2949 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2950 disabled by default; run isabelle with option -m HOL to get back to
  2951 the original Gordon/HOL-style output;
  2952 
  2953 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2954 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2955 
  2956 * HOL basic syntax simplified (more orthogonal): all variants of
  2957 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2958 Eps operator is provided as well: "SOME x. P[x]";
  2959 
  2960 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2961 
  2962 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2963 thus available for user theories;
  2964 
  2965 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2966 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2967 time;
  2968 
  2969 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2970 several times and then mp;
  2971 
  2972 
  2973 *** LK ***
  2974 
  2975 * the notation <<...>> is now available as a notation for sequences of
  2976 formulas;
  2977 
  2978 * the simplifier is now installed
  2979 
  2980 * the axiom system has been generalized (thanks to Soren Heilmann)
  2981 
  2982 * the classical reasoner now has a default rule database
  2983 
  2984 
  2985 *** ZF ***
  2986 
  2987 * new primrec section allows primitive recursive functions to be given
  2988 directly (as in HOL) over datatypes and the natural numbers;
  2989 
  2990 * new tactics induct_tac and exhaust_tac for induction (or case
  2991 analysis) over datatypes and the natural numbers;
  2992 
  2993 * the datatype declaration of type T now defines the recursor T_rec;
  2994 
  2995 * simplification automatically does freeness reasoning for datatype
  2996 constructors;
  2997 
  2998 * automatic type-inference, with AddTCs command to insert new
  2999 type-checking rules;
  3000 
  3001 * datatype introduction rules are now added as Safe Introduction rules
  3002 to the claset;
  3003 
  3004 * the syntax "if P then x else y" is now available in addition to
  3005 if(P,x,y);
  3006 
  3007 
  3008 *** Internal programming interfaces ***
  3009 
  3010 * tuned simplifier trace output; new flag debug_simp;
  3011 
  3012 * structures Vartab / Termtab (instances of TableFun) offer efficient
  3013 tables indexed by indexname_ord / term_ord (compatible with aconv);
  3014 
  3015 * AxClass.axclass_tac lost the theory argument;
  3016 
  3017 * tuned current_goals_markers semantics: begin / end goal avoids
  3018 printing empty lines;
  3019 
  3020 * removed prs and prs_fn hook, which was broken because it did not
  3021 include \n in its semantics, forcing writeln to add one
  3022 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  3023 string -> unit if you really want to output text without newline;
  3024 
  3025 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  3026 plain output, interface builders may have to enable 'isabelle_font'
  3027 mode to get Isabelle font glyphs as before;
  3028 
  3029 * refined token_translation interface; INCOMPATIBILITY: output length
  3030 now of type real instead of int;
  3031 
  3032 * theory loader actions may be traced via new ThyInfo.add_hook
  3033 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  3034 your own database of information attached to *whole* theories -- as
  3035 opposed to intra-theory data slots offered via TheoryDataFun;
  3036 
  3037 * proper handling of dangling sort hypotheses (at last!);
  3038 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  3039 extra sort hypotheses that can be witnessed from the type signature;
  3040 the force_strip_shyps flag is gone, any remaining shyps are simply
  3041 left in the theorem (with a warning issued by strip_shyps_warning);
  3042 
  3043 
  3044 
  3045 New in Isabelle98-1 (October 1998)
  3046 ----------------------------------
  3047 
  3048 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3049 
  3050 * several changes of automated proof tools;
  3051 
  3052 * HOL: major changes to the inductive and datatype packages, including
  3053 some minor incompatibilities of theory syntax;
  3054 
  3055 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  3056 called `inj_on';
  3057 
  3058 * HOL: removed duplicate thms in Arith:
  3059   less_imp_add_less  should be replaced by  trans_less_add1
  3060   le_imp_add_le      should be replaced by  trans_le_add1
  3061 
  3062 * HOL: unary minus is now overloaded (new type constraints may be
  3063 required);
  3064 
  3065 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  3066 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  3067 now taken as an integer constant.
  3068 
  3069 * Pure: ML function 'theory_of' renamed to 'theory';
  3070 
  3071 
  3072 *** Proof tools ***
  3073 
  3074 * Simplifier:
  3075   1. Asm_full_simp_tac is now more aggressive.
  3076      1. It will sometimes reorient premises if that increases their power to
  3077         simplify.
  3078      2. It does no longer proceed strictly from left to right but may also
  3079         rotate premises to achieve further simplification.
  3080      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  3081      old Asm_full_simp_tac in that it does not rotate premises.
  3082   2. The simplifier now knows a little bit about nat-arithmetic.
  3083 
  3084 * Classical reasoner: wrapper mechanism for the classical reasoner now
  3085 allows for selected deletion of wrappers, by introduction of names for
  3086 wrapper functionals.  This implies that addbefore, addSbefore,
  3087 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  3088 and that adding two tactics with the same name overwrites the first
  3089 one (emitting a warning).
  3090   type wrapper = (int -> tactic) -> (int -> tactic)
  3091   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  3092   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  3093   delWrapper, delSWrapper: claset *  string            -> claset
  3094   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  3095 
  3096 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  3097 semantics; addbefore now affects only the unsafe part of step_tac
  3098 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  3099 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  3100 by Force_tac;
  3101 
  3102 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  3103 compWrapper; added safe wrapper (and access functions for it);
  3104 
  3105 * HOL/split_all_tac is now much faster and fails if there is nothing
  3106 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  3107 and the names of the automatically generated variables have changed.
  3108 split_all_tac has moved within claset() from unsafe wrappers to safe
  3109 wrappers, which means that !!-bound variables are split much more
  3110 aggressively, and safe_tac and clarify_tac now split such variables.
  3111 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  3112 Note: the same holds for record_split_tac, which does the job of
  3113 split_all_tac for record fields.
  3114 
  3115 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  3116 permanently to the default simpset using Addsplits just like
  3117 Addsimps. They can be removed via Delsplits just like
  3118 Delsimps. Lower-case versions are also available.
  3119 
  3120 * HOL/Simplifier: The rule split_if is now part of the default
  3121 simpset. This means that the simplifier will eliminate all occurrences
  3122 of if-then-else in the conclusion of a goal. To prevent this, you can
  3123 either remove split_if completely from the default simpset by
  3124 `Delsplits [split_if]' or remove it in a specific call of the
  3125 simplifier using `... delsplits [split_if]'.  You can also add/delete
  3126 other case splitting rules to/from the default simpset: every datatype
  3127 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  3128 t is the name of the datatype).
  3129 
  3130 * Classical reasoner / Simplifier combination: new force_tac (and
  3131 derivatives Force_tac, force) combines rewriting and classical
  3132 reasoning (and whatever other tools) similarly to auto_tac, but is
  3133 aimed to solve the given subgoal completely.
  3134 
  3135 
  3136 *** General ***
  3137 
  3138 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  3139 and `goalw': the theory is no longer needed as an explicit argument -
  3140 the current theory context is used; assumptions are no longer returned
  3141 at the ML-level unless one of them starts with ==> or !!; it is
  3142 recommended to convert to these new commands using isatool fixgoal
  3143 (backup your sources first!);
  3144 
  3145 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  3146 the current theory context, and 'theory' to lookup stored theories;
  3147 
  3148 * new theory section 'locale' for declaring constants, assumptions and
  3149 definitions that have local scope;
  3150 
  3151 * new theory section 'nonterminals' for purely syntactic types;
  3152 
  3153 * new theory section 'setup' for generic ML setup functions
  3154 (e.g. package initialization);
  3155 
  3156 * the distribution now includes Isabelle icons: see
  3157 lib/logo/isabelle-{small,tiny}.xpm;
  3158 
  3159 * isatool install - install binaries with absolute references to
  3160 ISABELLE_HOME/bin;
  3161 
  3162 * isatool logo -- create instances of the Isabelle logo (as EPS);
  3163 
  3164 * print mode 'emacs' reserved for Isamode;
  3165 
  3166 * support multiple print (ast) translations per constant name;
  3167 
  3168 * theorems involving oracles are now printed with a suffixed [!];
  3169 
  3170 
  3171 *** HOL ***
  3172 
  3173 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  3174 
  3175 * HOL/inductive package reorganized and improved: now supports mutual
  3176 definitions such as
  3177 
  3178   inductive EVEN ODD
  3179     intrs
  3180       null "0 : EVEN"
  3181       oddI "n : EVEN ==> Suc n : ODD"
  3182       evenI "n : ODD ==> Suc n : EVEN"
  3183 
  3184 new theorem list "elims" contains an elimination rule for each of the
  3185 recursive sets; inductive definitions now handle disjunctive premises
  3186 correctly (also ZF);
  3187 
  3188 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  3189 "mutual_induct" no longer exists - the induction rule is always
  3190 contained in "induct";
  3191 
  3192 
  3193 * HOL/datatype package re-implemented and greatly improved: now
  3194 supports mutually recursive datatypes such as
  3195 
  3196   datatype
  3197     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  3198             | SUM ('a aexp) ('a aexp)
  3199             | DIFF ('a aexp) ('a aexp)
  3200             | NUM 'a
  3201   and
  3202     'a bexp = LESS ('a aexp) ('a aexp)
  3203             | AND ('a bexp) ('a bexp)
  3204             | OR ('a bexp) ('a bexp)
  3205 
  3206 as well as indirectly recursive datatypes such as
  3207 
  3208   datatype
  3209     ('a, 'b) term = Var 'a
  3210                   | App 'b ((('a, 'b) term) list)
  3211 
  3212 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  3213 induction on mutually / indirectly recursive datatypes.
  3214 
  3215 Primrec equations are now stored in theory and can be accessed via
  3216 <function_name>.simps.
  3217 
  3218 INCOMPATIBILITIES:
  3219 
  3220   - Theories using datatypes must now have theory Datatype as an
  3221     ancestor.
  3222   - The specific <typename>.induct_tac no longer exists - use the
  3223     generic induct_tac instead.
  3224   - natE has been renamed to nat.exhaust - use exhaust_tac
  3225     instead of res_inst_tac ... natE. Note that the variable
  3226     names in nat.exhaust differ from the names in natE, this
  3227     may cause some "fragile" proofs to fail.
  3228   - The theorems split_<typename>_case and split_<typename>_case_asm
  3229     have been renamed to <typename>.split and <typename>.split_asm.
  3230   - Since default sorts of type variables are now handled correctly,
  3231     some datatype definitions may have to be annotated with explicit
  3232     sort constraints.
  3233   - Primrec definitions no longer require function name and type
  3234     of recursive argument.
  3235 
  3236 Consider using isatool fixdatatype to adapt your theories and proof
  3237 scripts to the new package (backup your sources first!).
  3238 
  3239 
  3240 * HOL/record package: considerably improved implementation; now
  3241 includes concrete syntax for record types, terms, updates; theorems
  3242 for surjective pairing and splitting !!-bound record variables; proof
  3243 support is as follows:
  3244 
  3245   1) standard conversions (selectors or updates applied to record
  3246 constructor terms) are part of the standard simpset;
  3247 
  3248   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  3249 made part of standard simpset and claset via addIffs;
  3250 
  3251   3) a tactic for record field splitting (record_split_tac) is part of
  3252 the standard claset (addSWrapper);
  3253 
  3254 To get a better idea about these rules you may retrieve them via
  3255 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  3256 the name of your record type.
  3257 
  3258 The split tactic 3) conceptually simplifies by the following rule:
  3259 
  3260   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  3261 
  3262 Thus any record variable that is bound by meta-all will automatically
  3263 blow up into some record constructor term, consequently the
  3264 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  3265 solve record problems automatically.
  3266 
  3267 
  3268 * reorganized the main HOL image: HOL/Integ and String loaded by
  3269 default; theory Main includes everything;
  3270 
  3271 * automatic simplification of integer sums and comparisons, using cancellation;
  3272 
  3273 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  3274 
  3275 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  3276 
  3277 * many new identities for unions, intersections, set difference, etc.;
  3278 
  3279 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  3280 called split_if, split_split, split_sum_case and split_nat_case (to go
  3281 with add/delsplits);
  3282 
  3283 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  3284 (?x::unit) = (); this is made part of the default simpset, which COULD
  3285 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  3286 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  3287 unit_abs_eta_conv is added in order to counter the effect of
  3288 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  3289 %u.f();
  3290 
  3291 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  3292 makes more sense);
  3293 
  3294 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3295   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3296   disjointness reasoning but breaking a few old proofs.
  3297 
  3298 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  3299 to 'converse' from 'inverse' (for compatibility with ZF and some
  3300 literature);
  3301 
  3302 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  3303 the well-founded relation;
  3304 
  3305 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  3306     Compl A.  The "Compl" syntax remains available as input syntax for this
  3307     release ONLY.
  3308 
  3309 * HOL/Update: new theory of function updates:
  3310     f(a:=b) == %x. if x=a then b else f x
  3311 may also be iterated as in f(a:=b,c:=d,...);
  3312 
  3313 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  3314 
  3315 * HOL/List:
  3316   - new function list_update written xs[i:=v] that updates the i-th
  3317     list position. May also be iterated as in xs[i:=a,j:=b,...].
  3318   - new function `upt' written [i..j(] which generates the list
  3319     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  3320     bound write [i..j], which is a shorthand for [i..j+1(].
  3321   - new lexicographic orderings and corresponding wellfoundedness theorems.
  3322 
  3323 * HOL/Arith:
  3324   - removed 'pred' (predecessor) function;
  3325   - generalized some theorems about n-1;
  3326   - many new laws about "div" and "mod";
  3327   - new laws about greatest common divisors (see theory ex/Primes);
  3328 
  3329 * HOL/Relation: renamed the relational operator r^-1 "converse"
  3330 instead of "inverse";
  3331 
  3332 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  3333   of the multiset ordering;
  3334 
  3335 * directory HOL/Real: a construction of the reals using Dedekind cuts
  3336   (not included by default);
  3337 
  3338 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  3339 
  3340 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  3341   programs, i.e. different program variables may have different types.
  3342 
  3343 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3344   [previously, this check worked only if the rewrite rule was unconditional]
  3345   Now rew can involve either definitions or equalities (either == or =).
  3346 
  3347 
  3348 *** ZF ***
  3349 
  3350 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  3351   only the theorems proved on ZF.ML;
  3352 
  3353 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  3354   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  3355   disjointness reasoning but breaking a few old proofs.
  3356 
  3357 * ZF/Update: new theory of function updates
  3358     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  3359   may also be iterated as in f(a:=b,c:=d,...);
  3360 
  3361 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  3362 
  3363 * calling (stac rew i) now fails if "rew" has no effect on the goal
  3364   [previously, this check worked only if the rewrite rule was unconditional]
  3365   Now rew can involve either definitions or equalities (either == or =).
  3366 
  3367 * case_tac provided for compatibility with HOL
  3368     (like the old excluded_middle_tac, but with subgoals swapped)
  3369 
  3370 
  3371 *** Internal programming interfaces ***
  3372 
  3373 * Pure: several new basic modules made available for general use, see
  3374 also src/Pure/README;
  3375 
  3376 * improved the theory data mechanism to support encapsulation (data
  3377 kind name replaced by private Object.kind, acting as authorization
  3378 key); new type-safe user interface via functor TheoryDataFun; generic
  3379 print_data function becomes basically useless;
  3380 
  3381 * removed global_names compatibility flag -- all theory declarations
  3382 are qualified by default;
  3383 
  3384 * module Pure/Syntax now offers quote / antiquote translation
  3385 functions (useful for Hoare logic etc. with implicit dependencies);
  3386 see HOL/ex/Antiquote for an example use;
  3387 
  3388 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  3389 cterm -> thm;
  3390 
  3391 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  3392 subgoal;
  3393 
  3394 * Display.print_goals function moved to Locale.print_goals;
  3395 
  3396 * standard print function for goals supports current_goals_markers
  3397 variable for marking begin of proof, end of proof, start of goal; the
  3398 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  3399 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  3400 for example;
  3401 
  3402 
  3403 
  3404 New in Isabelle98 (January 1998)
  3405 --------------------------------
  3406 
  3407 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  3408 
  3409 * changed lexical syntax of terms / types: dots made part of long
  3410 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  3411 
  3412 * simpset (and claset) reference variable replaced by functions
  3413 simpset / simpset_ref;
  3414 
  3415 * no longer supports theory aliases (via merge) and non-trivial
  3416 implicit merge of thms' signatures;
  3417 
  3418 * most internal names of constants changed due to qualified names;
  3419 
  3420 * changed Pure/Sequence interface (see Pure/seq.ML);
  3421 
  3422 
  3423 *** General Changes ***
  3424 
  3425 * hierachically structured name spaces (for consts, types, axms, thms
  3426 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  3427 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  3428 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  3429 long_names for fully qualified output names; NOTE: ML programs
  3430 (special tactics, packages etc.) referring to internal names may have
  3431 to be adapted to cope with fully qualified names; in case of severe
  3432 backward campatibility problems try setting 'global_names' at compile
  3433 time to have enrything declared within a flat name space; one may also
  3434 fine tune name declarations in theories via the 'global' and 'local'
  3435 section;
  3436 
  3437 * reimplemented the implicit simpset and claset using the new anytype
  3438 data filed in signatures; references simpset:simpset ref etc. are
  3439 replaced by functions simpset:unit->simpset and
  3440 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  3441 to patch your ML files accordingly;
  3442 
  3443 * HTML output now includes theory graph data for display with Java
  3444 applet or isatool browser; data generated automatically via isatool
  3445 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  3446 
  3447 * defs may now be conditional; improved rewrite_goals_tac to handle
  3448 conditional equations;
  3449 
  3450 * defs now admits additional type arguments, using TYPE('a) syntax;
  3451 
  3452 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  3453 creates a new theory node; implicit merge of thms' signatures is
  3454 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  3455 transfer:theory->thm->thm in (rare) cases;
  3456 
  3457 * improved handling of draft signatures / theories; draft thms (and
  3458 ctyps, cterms) are automatically promoted to real ones;
  3459 
  3460 * slightly changed interfaces for oracles: admit many per theory, named
  3461 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  3462 
  3463 * print_goals: optional output of const types (set show_consts and
  3464 show_types);
  3465 
  3466 * improved output of warnings (###) and errors (***);
  3467 
  3468 * subgoal_tac displays a warning if the new subgoal has type variables;
  3469 
  3470 * removed old README and Makefiles;
  3471 
  3472 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  3473 
  3474 * removed obsolete init_pps and init_database;
  3475 
  3476 * deleted the obsolete tactical STATE, which was declared by
  3477     fun STATE tacfun st = tacfun st st;
  3478 
  3479 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  3480 (which abbreviates $HOME);
  3481 
  3482 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  3483 use isatool fixseq to adapt your ML programs (this works for fully
  3484 qualified references to the Sequence structure only!);
  3485 
  3486 * use_thy no longer requires writable current directory; it always
  3487 reloads .ML *and* .thy file, if either one is out of date;
  3488 
  3489 
  3490 *** Classical Reasoner ***
  3491 
  3492 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  3493 tactics that use classical reasoning to simplify a subgoal without
  3494 splitting it into several subgoals;
  3495 
  3496 * Safe_tac: like safe_tac but uses the default claset;
  3497 
  3498 
  3499 *** Simplifier ***
  3500 
  3501 * added simplification meta rules:
  3502     (asm_)(full_)simplify: simpset -> thm -> thm;
  3503 
  3504 * simplifier.ML no longer part of Pure -- has to be loaded by object
  3505 logics (again);
  3506 
  3507 * added prems argument to simplification procedures;
  3508 
  3509 * HOL, FOL, ZF: added infix function `addsplits':
  3510   instead of `<simpset> setloop (split_tac <thms>)'
  3511   you can simply write `<simpset> addsplits <thms>'
  3512 
  3513 
  3514 *** Syntax ***
  3515 
  3516 * TYPE('a) syntax for type reflection terms;
  3517 
  3518 * no longer handles consts with name "" -- declare as 'syntax' instead;
  3519 
  3520 * pretty printer: changed order of mixfix annotation preference (again!);
  3521 
  3522 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  3523 
  3524 
  3525 *** HOL ***
  3526 
  3527 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3528   with `addloop' of the simplifier to faciliate case splitting in premises.
  3529 
  3530 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  3531 
  3532 * HOL/Auth: new protocol proofs including some for the Internet
  3533   protocol TLS;
  3534 
  3535 * HOL/Map: new theory of `maps' a la VDM;
  3536 
  3537 * HOL/simplifier: simplification procedures nat_cancel_sums for
  3538 cancelling out common nat summands from =, <, <= (in)equalities, or
  3539 differences; simplification procedures nat_cancel_factor for
  3540 cancelling common factor from =, <, <= (in)equalities over natural
  3541 sums; nat_cancel contains both kinds of procedures, it is installed by
  3542 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  3543 
  3544 * HOL/simplifier: terms of the form
  3545   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  3546   are rewritten to
  3547   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  3548   and those of the form
  3549   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  3550   are rewritten to
  3551   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  3552 
  3553 * HOL/datatype
  3554   Each datatype `t' now comes with a theorem `split_t_case' of the form
  3555 
  3556   P(t_case f1 ... fn x) =
  3557      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  3558         ...
  3559        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  3560      )
  3561 
  3562   and a theorem `split_t_case_asm' of the form
  3563 
  3564   P(t_case f1 ... fn x) =
  3565     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  3566         ...
  3567        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  3568      )
  3569   which can be added to a simpset via `addsplits'. The existing theorems
  3570   expand_list_case and expand_option_case have been renamed to
  3571   split_list_case and split_option_case.
  3572 
  3573 * HOL/Arithmetic:
  3574   - `pred n' is automatically converted to `n-1'.
  3575     Users are strongly encouraged not to use `pred' any longer,
  3576     because it will disappear altogether at some point.
  3577   - Users are strongly encouraged to write "0 < n" rather than
  3578     "n ~= 0". Theorems and proof tools have been modified towards this
  3579     `standard'.
  3580 
  3581 * HOL/Lists:
  3582   the function "set_of_list" has been renamed "set" (and its theorems too);
  3583   the function "nth" now takes its arguments in the reverse order and
  3584   has acquired the infix notation "!" as in "xs!n".
  3585 
  3586 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  3587 
  3588 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  3589   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  3590 
  3591 * HOL/record: extensible records with schematic structural subtyping
  3592 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  3593 still lacks various theorems and concrete record syntax;
  3594 
  3595 
  3596 *** HOLCF ***
  3597 
  3598 * removed "axioms" and "generated by" sections;
  3599 
  3600 * replaced "ops" section by extended "consts" section, which is capable of
  3601   handling the continuous function space "->" directly;
  3602 
  3603 * domain package:
  3604   . proves theorems immediately and stores them in the theory,
  3605   . creates hierachical name space,
  3606   . now uses normal mixfix annotations (instead of cinfix...),
  3607   . minor changes to some names and values (for consistency),
  3608   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  3609   . separator between mutual domain defs: changed "," to "and",
  3610   . improved handling of sort constraints;  now they have to
  3611     appear on the left-hand side of the equations only;
  3612 
  3613 * fixed LAM <x,y,zs>.b syntax;
  3614 
  3615 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  3616 adm (%x. P (t x)), where P is chainfinite and t continuous;
  3617 
  3618 
  3619 *** FOL and ZF ***
  3620 
  3621 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  3622   with `addloop' of the simplifier to faciliate case splitting in premises.
  3623 
  3624 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  3625 in HOL, they strip ALL and --> from proved theorems;
  3626 
  3627 
  3628 
  3629 New in Isabelle94-8 (May 1997)
  3630 ------------------------------
  3631 
  3632 *** General Changes ***
  3633 
  3634 * new utilities to build / run / maintain Isabelle etc. (in parts
  3635 still somewhat experimental); old Makefiles etc. still functional;
  3636 
  3637 * new 'Isabelle System Manual';
  3638 
  3639 * INSTALL text, together with ./configure and ./build scripts;
  3640 
  3641 * reimplemented type inference for greater efficiency, better error
  3642 messages and clean internal interface;
  3643 
  3644 * prlim command for dealing with lots of subgoals (an easier way of
  3645 setting goals_limit);
  3646 
  3647 
  3648 *** Syntax ***
  3649 
  3650 * supports alternative (named) syntax tables (parser and pretty
  3651 printer); internal interface is provided by add_modesyntax(_i);
  3652 
  3653 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  3654 be used in conjunction with the Isabelle symbol font; uses the
  3655 "symbols" syntax table;
  3656 
  3657 * added token_translation interface (may translate name tokens in
  3658 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  3659 the current print_mode); IMPORTANT: user print translation functions
  3660 are responsible for marking newly introduced bounds
  3661 (Syntax.mark_boundT);
  3662 
  3663 * token translations for modes "xterm" and "xterm_color" that display
  3664 names in bold, underline etc. or colors (which requires a color
  3665 version of xterm);
  3666 
  3667 * infixes may now be declared with names independent of their syntax;
  3668 
  3669 * added typed_print_translation (like print_translation, but may
  3670 access type of constant);
  3671 
  3672 
  3673 *** Classical Reasoner ***
  3674 
  3675 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  3676 some limitations.  Blast_tac...
  3677   + ignores addss, addbefore, addafter; this restriction is intrinsic
  3678   + ignores elimination rules that don't have the correct format
  3679         (the conclusion MUST be a formula variable)
  3680   + ignores types, which can make HOL proofs fail
  3681   + rules must not require higher-order unification, e.g. apply_type in ZF
  3682     [message "Function Var's argument not a bound variable" relates to this]
  3683   + its proof strategy is more general but can actually be slower
  3684 
  3685 * substitution with equality assumptions no longer permutes other
  3686 assumptions;
  3687 
  3688 * minor changes in semantics of addafter (now called addaltern); renamed
  3689 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  3690 (and access functions for it);
  3691 
  3692 * improved combination of classical reasoner and simplifier:
  3693   + functions for handling clasimpsets
  3694   + improvement of addss: now the simplifier is called _after_ the
  3695     safe steps.
  3696   + safe variant of addss called addSss: uses safe simplifications
  3697     _during_ the safe steps. It is more complete as it allows multiple
  3698     instantiations of unknowns (e.g. with slow_tac).
  3699 
  3700 *** Simplifier ***
  3701 
  3702 * added interface for simplification procedures (functions that
  3703 produce *proven* rewrite rules on the fly, depending on current
  3704 redex);
  3705 
  3706 * ordering on terms as parameter (used for ordered rewriting);
  3707 
  3708 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  3709 
  3710 * the solver is now split into a safe and an unsafe part.
  3711 This should be invisible for the normal user, except that the
  3712 functions setsolver and addsolver have been renamed to setSolver and
  3713 addSolver; added safe_asm_full_simp_tac;
  3714 
  3715 
  3716 *** HOL ***
  3717 
  3718 * a generic induction tactic `induct_tac' which works for all datatypes and
  3719 also for type `nat';
  3720 
  3721 * a generic case distinction tactic `exhaust_tac' which works for all
  3722 datatypes and also for type `nat';
  3723 
  3724 * each datatype comes with a function `size';
  3725 
  3726 * patterns in case expressions allow tuple patterns as arguments to
  3727 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  3728 
  3729 * primrec now also works with type nat;
  3730 
  3731 * recdef: a new declaration form, allows general recursive functions to be
  3732 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  3733 
  3734 * the constant for negation has been renamed from "not" to "Not" to
  3735 harmonize with FOL, ZF, LK, etc.;
  3736 
  3737 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  3738 infinite lists;
  3739 
  3740 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  3741 
  3742 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  3743 problems in commutative rings, using axiomatic type classes for + and *;
  3744 
  3745 * more examples in HOL/MiniML and HOL/Auth;
  3746 
  3747 * more default rewrite rules for quantifiers, union/intersection;
  3748 
  3749 * a new constant `arbitrary == @x.False';
  3750 
  3751 * HOLCF/IOA replaces old HOL/IOA;
  3752 
  3753 * HOLCF changes: derived all rules and arities
  3754   + axiomatic type classes instead of classes
  3755   + typedef instead of faking type definitions
  3756   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  3757   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  3758   + eliminated the types void, one, tr
  3759   + use unit lift and bool lift (with translations) instead of one and tr
  3760   + eliminated blift from Lift3.thy (use Def instead of blift)
  3761   all eliminated rules are derived as theorems --> no visible changes ;
  3762 
  3763 
  3764 *** ZF ***
  3765 
  3766 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  3767 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  3768 as ZF_cs addSIs [equalityI];
  3769 
  3770 
  3771 
  3772 New in Isabelle94-7 (November 96)
  3773 ---------------------------------
  3774 
  3775 * allowing negative levels (as offsets) in prlev and choplev;
  3776 
  3777 * super-linear speedup for large simplifications;
  3778 
  3779 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  3780 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  3781 FAIL); can suppress it using the command Delsimps (ex_simps @
  3782 all_simps); De Morgan laws are also now included, by default;
  3783 
  3784 * improved printing of ==>  :  ~:
  3785 
  3786 * new object-logic "Sequents" adds linear logic, while replacing LK
  3787 and Modal (thanks to Sara Kalvala);
  3788 
  3789 * HOL/Auth: correctness proofs for authentication protocols;
  3790 
  3791 * HOL: new auto_tac combines rewriting and classical reasoning (many
  3792 examples on HOL/Auth);
  3793 
  3794 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  3795 the rewriter and classical reasoner simultaneously;
  3796 
  3797 * function uresult no longer returns theorems in "standard" format;
  3798 regain previous version by: val uresult = standard o uresult;
  3799 
  3800 
  3801 
  3802 New in Isabelle94-6
  3803 -------------------
  3804 
  3805 * oracles -- these establish an interface between Isabelle and trusted
  3806 external reasoners, which may deliver results as theorems;
  3807 
  3808 * proof objects (in particular record all uses of oracles);
  3809 
  3810 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  3811 
  3812 * "constdefs" section in theory files;
  3813 
  3814 * "primrec" section (HOL) no longer requires names;
  3815 
  3816 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  3817 
  3818 
  3819 
  3820 New in Isabelle94-5
  3821 -------------------
  3822 
  3823 * reduced space requirements;
  3824 
  3825 * automatic HTML generation from theories;
  3826 
  3827 * theory files no longer require "..." (quotes) around most types;
  3828 
  3829 * new examples, including two proofs of the Church-Rosser theorem;
  3830 
  3831 * non-curried (1994) version of HOL is no longer distributed;
  3832 
  3833 
  3834 
  3835 New in Isabelle94-4
  3836 -------------------
  3837 
  3838 * greatly reduced space requirements;
  3839 
  3840 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3841 
  3842 * searchable theorem database (see the section "Retrieving theorems" on
  3843 page 8 of the Reference Manual);
  3844 
  3845 * new examples, including Grabczewski's monumental case study of the
  3846 Axiom of Choice;
  3847 
  3848 * The previous version of HOL renamed to Old_HOL;
  3849 
  3850 * The new version of HOL (previously called CHOL) uses a curried syntax
  3851 for functions.  Application looks like f a b instead of f(a,b);
  3852 
  3853 * Mutually recursive inductive definitions finally work in HOL;
  3854 
  3855 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3856 translates to the operator "split";
  3857 
  3858 
  3859 
  3860 New in Isabelle94-3
  3861 -------------------
  3862 
  3863 * new infix operator, addss, allowing the classical reasoner to
  3864 perform simplification at each step of its search.  Example:
  3865         fast_tac (cs addss ss)
  3866 
  3867 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3868 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3869 look like (a,b) instead of <a,b>;
  3870 
  3871 * PLEASE NOTE: CHOL will eventually replace HOL!
  3872 
  3873 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3874 It translates to the operator "split".  A new theory of integers is available;
  3875 
  3876 * In ZF, integer numerals now denote two's-complement binary integers.
  3877 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3878 
  3879 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3880 of the Axiom of Choice;
  3881 
  3882 
  3883 
  3884 New in Isabelle94-2
  3885 -------------------
  3886 
  3887 * Significantly faster resolution;
  3888 
  3889 * the different sections in a .thy file can now be mixed and repeated
  3890 freely;
  3891 
  3892 * Database of theorems for FOL, HOL and ZF.  New
  3893 commands including qed, qed_goal and bind_thm store theorems in the database.
  3894 
  3895 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3896 a given theory (thms_of), or find out what theory a theorem was proved in
  3897 (theory_of_thm);
  3898 
  3899 * Bugs fixed in the inductive definition and datatype packages;
  3900 
  3901 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3902 and HOL_dup_cs obsolete;
  3903 
  3904 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3905 have been removed;
  3906 
  3907 * Simpler definition of function space in ZF;
  3908 
  3909 * new results about cardinal and ordinal arithmetic in ZF;
  3910 
  3911 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3912 types;
  3913 
  3914 
  3915 $Id$