NEWS

if-then-else syntax for ZF

+
−Isabelle NEWS -- history user-relevant changes
+
−==============================================
+
−
+
−New in this Isabelle version
+
−----------------------------
+
−
+
−*** Overview of INCOMPATIBILITIES (see below for more details) ***
+
−
+
−* HOL: Removed the obsolete syntax "Compl A"; use -A for set complement
+
−
+
−* ZF: The con_defs part of an inductive definition may no longer refer to 
+
−  constants declared in the same theory;
+
−
+
−
+
−*** Proof tools ***
+
−
+
−* Provers/Arith/fast_lin_arith.ML contains a functor for creating a decision
+
−procedure for linear arithmetic. Currently it is used for types `nat' and
+
−`int' in HOL (see below) but can, should and will be instantiated for other
+
−types and logics as well.
+
−
+
−
+
−*** General ***
+
−
+
−* in locales, the "assumes" and "defines" parts may be omitted if empty;
+
−
+
−* new print_mode "xsymbols" for extended symbol support 
+
−  (e.g. genuiely long arrows)
+
−
+
−*** HOL ***
+
−
+
−* There are now decision procedures for linear arithmetic over nat and int:
+
−1. nat_arith_tac copes with arbitrary formulae involving `=', `<', `<=', 0,
+
−Suc, `+' and `-'; other subterms are treated as atomic; subformulae not
+
−involving type `nat' are ignored; quantified subformulae are ignored unless
+
−they are positive universal or negative existential. The tactic has to be
+
−invoked by hand and can be a little bit slow. In particular, the running time
+
−is exponential in the number of occurrences of `-'.
+
−2. fast_nat_arith_tac is a cut-down version of nat_arith_tac: it only takes
+
−(negated) (in)equalities among the premises and the conclusion into account
+
−(i.e. no compound formulae) and does not know about `-'. It is fast and is
+
−used automatically by the simplifier.
+
−3. int_arith_tac behaves like nat_arith_tac but applies to inequalities over
+
−`int';  it also knows about unary `-'; binary `-' does not cause a blow-up.
+
−4. fast_int_arith_tac is related to int_arith_tac like fast_nat_arith_tac is
+
−related to nat_arith_tac.
+
−NB: At the moment, these decision procedures do not cope with mixed nat/int
+
−formulae such as `m < n ==> int(m) < int(n)'.
+
−
+
−*** Internal programming interfaces ***
+
−
+
−* tuned current_goals_markers semantics: begin / end goal avoids
+
−printing empty lines;
+
−
+
−* removed prs and prs_fn hook, which was broken because it did not
+
−include \n in its semantics, forcing writeln to add one
+
−uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
+
−string -> unit if you really want to output text without newline;
+
−
+
−
+
−*** ZF ***
+
−
+
−* new primrec section allows primitive recursive functions to be given
+
−  directly, as in HOL;
+
−
+
−* new tactics induct_tac and exhaust_tac for induction (or case analysis)
+
−  on a datatype;
+
−
+
−* the datatype declaration of type T now defines the recursor T_rec;
+
−
+
−* The syntax "if P then x else y" is now available in addition to if(P,x,y).
+
−
+
−
+
−New in Isabelle98-1 (October 1998)
+
−----------------------------------
+
−
+
−*** Overview of INCOMPATIBILITIES (see below for more details) ***
+
−
+
−* several changes of automated proof tools;
+
−
+
−* HOL: major changes to the inductive and datatype packages, including
+
−some minor incompatibilities of theory syntax;
+
−
+
−* HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
+
−called `inj_on';
+
−
+
−* HOL: removed duplicate thms in Arith:
+
−  less_imp_add_less  should be replaced by  trans_less_add1
+
−  le_imp_add_le      should be replaced by  trans_le_add1
+
−
+
−* HOL: unary minus is now overloaded (new type constraints may be
+
−required);
+
−
+
−* HOL and ZF: unary minus for integers is now #- instead of #~.  In
+
−ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
+
−now taken as an integer constant.
+
−
+
−* Pure: ML function 'theory_of' renamed to 'theory';
+
−
+
−
+
−*** Proof tools ***
+
−
+
−* Simplifier:
+
−  1. Asm_full_simp_tac is now more aggressive.
+
−     1. It will sometimes reorient premises if that increases their power to
+
−        simplify.
+
−     2. It does no longer proceed strictly from left to right but may also
+
−        rotate premises to achieve further simplification.
+
−     For compatibility reasons there is now Asm_lr_simp_tac which is like the
+
−     old Asm_full_simp_tac in that it does not rotate premises.
+
−  2. The simplifier now knows a little bit about nat-arithmetic.
+
−
+
−* Classical reasoner: wrapper mechanism for the classical reasoner now
+
−allows for selected deletion of wrappers, by introduction of names for
+
−wrapper functionals.  This implies that addbefore, addSbefore,
+
−addaltern, and addSaltern now take a pair (name, tactic) as argument,
+
−and that adding two tactics with the same name overwrites the first
+
−one (emitting a warning).
+
−  type wrapper = (int -> tactic) -> (int -> tactic)
+
−  setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
+
−  addWrapper, addSWrapper: claset * (string * wrapper) -> claset
+
−  delWrapper, delSWrapper: claset *  string            -> claset
+
−  getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
+
−
+
−* Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
+
−semantics; addbefore now affects only the unsafe part of step_tac
+
−etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
+
−FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
+
−by Force_tac;
+
−
+
−* Classical reasoner: setwrapper to setWrapper and compwrapper to
+
−compWrapper; added safe wrapper (and access functions for it);
+
−
+
−* HOL/split_all_tac is now much faster and fails if there is nothing
+
−to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
+
−and the names of the automatically generated variables have changed.
+
−split_all_tac has moved within claset() from unsafe wrappers to safe
+
−wrappers, which means that !!-bound variables are split much more
+
−aggressively, and safe_tac and clarify_tac now split such variables.
+
−If this splitting is not appropriate, use delSWrapper "split_all_tac".
+
−Note: the same holds for record_split_tac, which does the job of
+
−split_all_tac for record fields.
+
−
+
−* HOL/Simplifier: Rewrite rules for case distinctions can now be added
+
−permanently to the default simpset using Addsplits just like
+
−Addsimps. They can be removed via Delsplits just like
+
−Delsimps. Lower-case versions are also available.
+
−
+
−* HOL/Simplifier: The rule split_if is now part of the default
+
−simpset. This means that the simplifier will eliminate all occurrences
+
−of if-then-else in the conclusion of a goal. To prevent this, you can
+
−either remove split_if completely from the default simpset by
+
−`Delsplits [split_if]' or remove it in a specific call of the
+
−simplifier using `... delsplits [split_if]'.  You can also add/delete
+
−other case splitting rules to/from the default simpset: every datatype
+
−generates suitable rules `split_t_case' and `split_t_case_asm' (where
+
−t is the name of the datatype).
+
−
+
−* Classical reasoner / Simplifier combination: new force_tac (and
+
−derivatives Force_tac, force) combines rewriting and classical
+
−reasoning (and whatever other tools) similarly to auto_tac, but is
+
−aimed to solve the given subgoal completely.
+
−
+
−
+
−*** General ***
+
−
+
−* new top-level commands `Goal' and `Goalw' that improve upon `goal'
+
−and `goalw': the theory is no longer needed as an explicit argument -
+
−the current theory context is used; assumptions are no longer returned
+
−at the ML-level unless one of them starts with ==> or !!; it is
+
−recommended to convert to these new commands using isatool fixgoal
+
−(backup your sources first!);
+
−
+
−* new top-level commands 'thm' and 'thms' for retrieving theorems from
+
−the current theory context, and 'theory' to lookup stored theories;
+
−
+
−* new theory section 'locale' for declaring constants, assumptions and
+
−definitions that have local scope;
+
−
+
−* new theory section 'nonterminals' for purely syntactic types;
+
−
+
−* new theory section 'setup' for generic ML setup functions
+
−(e.g. package initialization);
+
−
+
−* the distribution now includes Isabelle icons: see
+
−lib/logo/isabelle-{small,tiny}.xpm;
+
−
+
−* isatool install - install binaries with absolute references to
+
−ISABELLE_HOME/bin;
+
−
+
−* isatool logo -- create instances of the Isabelle logo (as EPS);
+
−
+
−* print mode 'emacs' reserved for Isamode;
+
−
+
−* support multiple print (ast) translations per constant name;
+
−
+
−
+
−*** HOL ***
+
−
+
−* there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
+
−
+
−* HOL/inductive package reorganized and improved: now supports mutual
+
−definitions such as
+
−
+
−  inductive EVEN ODD
+
−    intrs
+
−      null "0 : EVEN"
+
−      oddI "n : EVEN ==> Suc n : ODD"
+
−      evenI "n : ODD ==> Suc n : EVEN"
+
−
+
−new theorem list "elims" contains an elimination rule for each of the
+
−recursive sets; inductive definitions now handle disjunctive premises
+
−correctly (also ZF);
+
−
+
−INCOMPATIBILITIES: requires Inductive as an ancestor; component
+
−"mutual_induct" no longer exists - the induction rule is always
+
−contained in "induct";
+
−
+
−
+
−* HOL/datatype package re-implemented and greatly improved: now
+
−supports mutually recursive datatypes such as
+
−
+
−  datatype
+
−    'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
+
−            | SUM ('a aexp) ('a aexp)
+
−            | DIFF ('a aexp) ('a aexp)
+
−            | NUM 'a
+
−  and
+
−    'a bexp = LESS ('a aexp) ('a aexp)
+
−            | AND ('a bexp) ('a bexp)
+
−            | OR ('a bexp) ('a bexp)
+
−
+
−as well as indirectly recursive datatypes such as
+
−
+
−  datatype
+
−    ('a, 'b) term = Var 'a
+
−                  | App 'b ((('a, 'b) term) list)
+
−
+
−The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
+
−induction on mutually / indirectly recursive datatypes.
+
−
+
−Primrec equations are now stored in theory and can be accessed via
+
−<function_name>.simps.
+
−
+
−INCOMPATIBILITIES:
+
−
+
−  - Theories using datatypes must now have theory Datatype as an
+
−    ancestor.
+
−  - The specific <typename>.induct_tac no longer exists - use the
+
−    generic induct_tac instead.
+
−  - natE has been renamed to nat.exhaust - use exhaust_tac
+
−    instead of res_inst_tac ... natE. Note that the variable
+
−    names in nat.exhaust differ from the names in natE, this
+
−    may cause some "fragile" proofs to fail.
+
−  - The theorems split_<typename>_case and split_<typename>_case_asm
+
−    have been renamed to <typename>.split and <typename>.split_asm.
+
−  - Since default sorts of type variables are now handled correctly,
+
−    some datatype definitions may have to be annotated with explicit
+
−    sort constraints.
+
−  - Primrec definitions no longer require function name and type
+
−    of recursive argument.
+
−
+
−Consider using isatool fixdatatype to adapt your theories and proof
+
−scripts to the new package (backup your sources first!).
+
−
+
−
+
−* HOL/record package: considerably improved implementation; now
+
−includes concrete syntax for record types, terms, updates; theorems
+
−for surjective pairing and splitting !!-bound record variables; proof
+
−support is as follows:
+
−
+
−  1) standard conversions (selectors or updates applied to record
+
−constructor terms) are part of the standard simpset;
+
−
+
−  2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
+
−made part of standard simpset and claset via addIffs;
+
−
+
−  3) a tactic for record field splitting (record_split_tac) is part of
+
−the standard claset (addSWrapper);
+
−
+
−To get a better idea about these rules you may retrieve them via
+
−something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
+
−the name of your record type.
+
−
+
−The split tactic 3) conceptually simplifies by the following rule:
+
−
+
−  "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
+
−
+
−Thus any record variable that is bound by meta-all will automatically
+
−blow up into some record constructor term, consequently the
+
−simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
+
−solve record problems automatically.
+
−
+
−
+
−* reorganized the main HOL image: HOL/Integ and String loaded by
+
−default; theory Main includes everything;
+
−
+
−* automatic simplification of integer sums and comparisons, using cancellation;
+
−
+
−* added option_map_eq_Some and not_Some_eq to the default simpset and claset;
+
−
+
−* added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
+
−
+
−* many new identities for unions, intersections, set difference, etc.;
+
−
+
−* expand_if, expand_split, expand_sum_case and expand_nat_case are now
+
−called split_if, split_split, split_sum_case and split_nat_case (to go
+
−with add/delsplits);
+
−
+
−* HOL/Prod introduces simplification procedure unit_eq_proc rewriting
+
−(?x::unit) = (); this is made part of the default simpset, which COULD
+
−MAKE EXISTING PROOFS FAIL under rare circumstances (consider
+
−'Delsimprocs [unit_eq_proc];' as last resort); also note that
+
−unit_abs_eta_conv is added in order to counter the effect of
+
−unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
+
−%u.f();
+
−
+
−* HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
+
−makes more sense);
+
−
+
−* HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
+
−  It and 'sym RS equals0D' are now in the default  claset, giving automatic
+
−  disjointness reasoning but breaking a few old proofs.
+
−
+
−* HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
+
−to 'converse' from 'inverse' (for compatibility with ZF and some
+
−literature);
+
−
+
−* HOL/recdef can now declare non-recursive functions, with {} supplied as
+
−the well-founded relation;
+
−
+
−* HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
+
−    Compl A.  The "Compl" syntax remains available as input syntax for this
+
−    release ONLY.
+
−
+
−* HOL/Update: new theory of function updates:
+
−    f(a:=b) == %x. if x=a then b else f x
+
−may also be iterated as in f(a:=b,c:=d,...);
+
−
+
−* HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
+
−
+
−* HOL/List:
+
−  - new function list_update written xs[i:=v] that updates the i-th
+
−    list position. May also be iterated as in xs[i:=a,j:=b,...].
+
−  - new function `upt' written [i..j(] which generates the list
+
−    [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
+
−    bound write [i..j], which is a shorthand for [i..j+1(].
+
−  - new lexicographic orderings and corresponding wellfoundedness theorems.
+
−
+
−* HOL/Arith:
+
−  - removed 'pred' (predecessor) function;
+
−  - generalized some theorems about n-1;
+
−  - many new laws about "div" and "mod";
+
−  - new laws about greatest common divisors (see theory ex/Primes);
+
−
+
−* HOL/Relation: renamed the relational operator r^-1 "converse"
+
−instead of "inverse";
+
−
+
−* HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
+
−  of the multiset ordering;
+
−
+
−* directory HOL/Real: a construction of the reals using Dedekind cuts
+
−  (not included by default);
+
−
+
−* directory HOL/UNITY: Chandy and Misra's UNITY formalism;
+
−
+
−* directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
+
−  programs, i.e. different program variables may have different types.
+
−
+
−* calling (stac rew i) now fails if "rew" has no effect on the goal
+
−  [previously, this check worked only if the rewrite rule was unconditional]
+
−  Now rew can involve either definitions or equalities (either == or =).
+
−
+
−
+
−*** ZF ***
+
−
+
−* theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
+
−  only the theorems proved on ZF.ML;
+
−
+
−* ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
+
−  It and 'sym RS equals0D' are now in the default  claset, giving automatic
+
−  disjointness reasoning but breaking a few old proofs.
+
−
+
−* ZF/Update: new theory of function updates
+
−    with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
+
−  may also be iterated as in f(a:=b,c:=d,...);
+
−
+
−* in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
+
−
+
−* calling (stac rew i) now fails if "rew" has no effect on the goal
+
−  [previously, this check worked only if the rewrite rule was unconditional]
+
−  Now rew can involve either definitions or equalities (either == or =).
+
−
+
−* case_tac provided for compatibility with HOL
+
−    (like the old excluded_middle_tac, but with subgoals swapped)
+
−
+
−
+
−*** Internal programming interfaces ***
+
−
+
−* Pure: several new basic modules made available for general use, see
+
−also src/Pure/README;
+
−
+
−* improved the theory data mechanism to support encapsulation (data
+
−kind name replaced by private Object.kind, acting as authorization
+
−key); new type-safe user interface via functor TheoryDataFun; generic
+
−print_data function becomes basically useless;
+
−
+
−* removed global_names compatibility flag -- all theory declarations
+
−are qualified by default;
+
−
+
−* module Pure/Syntax now offers quote / antiquote translation
+
−functions (useful for Hoare logic etc. with implicit dependencies);
+
−see HOL/ex/Antiquote for an example use;
+
−
+
−* Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
+
−cterm -> thm;
+
−
+
−* new tactical CHANGED_GOAL for checking that a tactic modifies a
+
−subgoal;
+
−
+
−* Display.print_goals function moved to Locale.print_goals;
+
−
+
−* standard print function for goals supports current_goals_markers
+
−variable for marking begin of proof, end of proof, start of goal; the
+
−default is ("", "", ""); setting current_goals_markers := ("<proof>",
+
−"</proof>", "<goal>") causes SGML like tagged proof state printing,
+
−for example;
+
−
+
−
+
−
+
−New in Isabelle98 (January 1998)
+
−--------------------------------
+
−
+
−*** Overview of INCOMPATIBILITIES (see below for more details) ***
+
−
+
−* changed lexical syntax of terms / types: dots made part of long
+
−identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
+
−
+
−* simpset (and claset) reference variable replaced by functions
+
−simpset / simpset_ref;
+
−
+
−* no longer supports theory aliases (via merge) and non-trivial
+
−implicit merge of thms' signatures;
+
−
+
−* most internal names of constants changed due to qualified names;
+
−
+
−* changed Pure/Sequence interface (see Pure/seq.ML);
+
−
+
−
+
−*** General Changes ***
+
−
+
−* hierachically structured name spaces (for consts, types, axms, thms
+
−etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
+
−old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
+
−isatool fixdots ensures space after dots (e.g. "%x. x"); set
+
−long_names for fully qualified output names; NOTE: ML programs
+
−(special tactics, packages etc.) referring to internal names may have
+
−to be adapted to cope with fully qualified names; in case of severe
+
−backward campatibility problems try setting 'global_names' at compile
+
−time to have enrything declared within a flat name space; one may also
+
−fine tune name declarations in theories via the 'global' and 'local'
+
−section;
+
−
+
−* reimplemented the implicit simpset and claset using the new anytype
+
−data filed in signatures; references simpset:simpset ref etc. are
+
−replaced by functions simpset:unit->simpset and
+
−simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
+
−to patch your ML files accordingly;
+
−
+
−* HTML output now includes theory graph data for display with Java
+
−applet or isatool browser; data generated automatically via isatool
+
−usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
+
−
+
−* defs may now be conditional; improved rewrite_goals_tac to handle
+
−conditional equations;
+
−
+
−* defs now admits additional type arguments, using TYPE('a) syntax;
+
−
+
−* theory aliases via merge (e.g. M=A+B+C) no longer supported, always
+
−creates a new theory node; implicit merge of thms' signatures is
+
−restricted to 'trivial' ones; COMPATIBILITY: one may have to use
+
−transfer:theory->thm->thm in (rare) cases;
+
−
+
−* improved handling of draft signatures / theories; draft thms (and
+
−ctyps, cterms) are automatically promoted to real ones;
+
−
+
−* slightly changed interfaces for oracles: admit many per theory, named
+
−(e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
+
−
+
−* print_goals: optional output of const types (set show_consts and
+
−show_types);
+
−
+
−* improved output of warnings (###) and errors (***);
+
−
+
−* subgoal_tac displays a warning if the new subgoal has type variables;
+
−
+
−* removed old README and Makefiles;
+
−
+
−* replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
+
−
+
−* removed obsolete init_pps and init_database;
+
−
+
−* deleted the obsolete tactical STATE, which was declared by
+
−    fun STATE tacfun st = tacfun st st;
+
−
+
−* cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
+
−(which abbreviates $HOME);
+
−
+
−* changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
+
−use isatool fixseq to adapt your ML programs (this works for fully
+
−qualified references to the Sequence structure only!);
+
−
+
−* use_thy no longer requires writable current directory; it always
+
−reloads .ML *and* .thy file, if either one is out of date;
+
−
+
−
+
−*** Classical Reasoner ***
+
−
+
−* Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
+
−tactics that use classical reasoning to simplify a subgoal without
+
−splitting it into several subgoals;
+
−
+
−* Safe_tac: like safe_tac but uses the default claset;
+
−
+
−
+
−*** Simplifier ***
+
−
+
−* added simplification meta rules:
+
−    (asm_)(full_)simplify: simpset -> thm -> thm;
+
−
+
−* simplifier.ML no longer part of Pure -- has to be loaded by object
+
−logics (again);
+
−
+
−* added prems argument to simplification procedures;
+
−
+
−* HOL, FOL, ZF: added infix function `addsplits':
+
−  instead of `<simpset> setloop (split_tac <thms>)'
+
−  you can simply write `<simpset> addsplits <thms>'
+
−
+
−
+
−*** Syntax ***
+
−
+
−* TYPE('a) syntax for type reflection terms;
+
−
+
−* no longer handles consts with name "" -- declare as 'syntax' instead;
+
−
+
−* pretty printer: changed order of mixfix annotation preference (again!);
+
−
+
−* Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
+
−
+
−
+
−*** HOL ***
+
−
+
−* HOL: there is a new splitter `split_asm_tac' that can be used e.g.
+
−  with `addloop' of the simplifier to faciliate case splitting in premises.
+
−
+
−* HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
+
−
+
−* HOL/Auth: new protocol proofs including some for the Internet
+
−  protocol TLS;
+
−
+
−* HOL/Map: new theory of `maps' a la VDM;
+
−
+
−* HOL/simplifier: simplification procedures nat_cancel_sums for
+
−cancelling out common nat summands from =, <, <= (in)equalities, or
+
−differences; simplification procedures nat_cancel_factor for
+
−cancelling common factor from =, <, <= (in)equalities over natural
+
−sums; nat_cancel contains both kinds of procedures, it is installed by
+
−default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
+
−
+
−* HOL/simplifier: terms of the form
+
−  `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
+
−  are rewritten to
+
−  `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
+
−  and those of the form
+
−  `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
+
−  are rewritten to
+
−  `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
+
−
+
−* HOL/datatype
+
−  Each datatype `t' now comes with a theorem `split_t_case' of the form
+
−
+
−  P(t_case f1 ... fn x) =
+
−     ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
+
−        ...
+
−       (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
+
−     )
+
−
+
−  and a theorem `split_t_case_asm' of the form
+
−
+
−  P(t_case f1 ... fn x) =
+
−    ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
+
−        ...
+
−       (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
+
−     )
+
−  which can be added to a simpset via `addsplits'. The existing theorems
+
−  expand_list_case and expand_option_case have been renamed to
+
−  split_list_case and split_option_case.
+
−
+
−* HOL/Arithmetic:
+
−  - `pred n' is automatically converted to `n-1'.
+
−    Users are strongly encouraged not to use `pred' any longer,
+
−    because it will disappear altogether at some point.
+
−  - Users are strongly encouraged to write "0 < n" rather than
+
−    "n ~= 0". Theorems and proof tools have been modified towards this
+
−    `standard'.
+
−
+
−* HOL/Lists:
+
−  the function "set_of_list" has been renamed "set" (and its theorems too);
+
−  the function "nth" now takes its arguments in the reverse order and
+
−  has acquired the infix notation "!" as in "xs!n".
+
−
+
−* HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
+
−
+
−* HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
+
−  specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
+
−
+
−* HOL/record: extensible records with schematic structural subtyping
+
−(single inheritance); EXPERIMENTAL version demonstrating the encoding,
+
−still lacks various theorems and concrete record syntax;
+
−
+
−
+
−*** HOLCF ***
+
−
+
−* removed "axioms" and "generated by" sections;
+
−
+
−* replaced "ops" section by extended "consts" section, which is capable of
+
−  handling the continuous function space "->" directly;
+
−
+
−* domain package:
+
−  . proves theorems immediately and stores them in the theory,
+
−  . creates hierachical name space,
+
−  . now uses normal mixfix annotations (instead of cinfix...),
+
−  . minor changes to some names and values (for consistency),
+
−  . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
+
−  . separator between mutual domain defs: changed "," to "and",
+
−  . improved handling of sort constraints;  now they have to
+
−    appear on the left-hand side of the equations only;
+
−
+
−* fixed LAM <x,y,zs>.b syntax;
+
−
+
−* added extended adm_tac to simplifier in HOLCF -- can now discharge
+
−adm (%x. P (t x)), where P is chainfinite and t continuous;
+
−
+
−
+
−*** FOL and ZF ***
+
−
+
−* FOL: there is a new splitter `split_asm_tac' that can be used e.g.
+
−  with `addloop' of the simplifier to faciliate case splitting in premises.
+
−
+
−* qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
+
−in HOL, they strip ALL and --> from proved theorems;
+
−
+
−
+
−
+
−New in Isabelle94-8 (May 1997)
+
−------------------------------
+
−
+
−*** General Changes ***
+
−
+
−* new utilities to build / run / maintain Isabelle etc. (in parts
+
−still somewhat experimental); old Makefiles etc. still functional;
+
−
+
−* new 'Isabelle System Manual';
+
−
+
−* INSTALL text, together with ./configure and ./build scripts;
+
−
+
−* reimplemented type inference for greater efficiency, better error
+
−messages and clean internal interface;
+
−
+
−* prlim command for dealing with lots of subgoals (an easier way of
+
−setting goals_limit);
+
−
+
−
+
−*** Syntax ***
+
−
+
−* supports alternative (named) syntax tables (parser and pretty
+
−printer); internal interface is provided by add_modesyntax(_i);
+
−
+
−* Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
+
−be used in conjunction with the Isabelle symbol font; uses the
+
−"symbols" syntax table;
+
−
+
−* added token_translation interface (may translate name tokens in
+
−arbitrary ways, dependent on their type (free, bound, tfree, ...) and
+
−the current print_mode); IMPORTANT: user print translation functions
+
−are responsible for marking newly introduced bounds
+
−(Syntax.mark_boundT);
+
−
+
−* token translations for modes "xterm" and "xterm_color" that display
+
−names in bold, underline etc. or colors (which requires a color
+
−version of xterm);
+
−
+
−* infixes may now be declared with names independent of their syntax;
+
−
+
−* added typed_print_translation (like print_translation, but may
+
−access type of constant);
+
−
+
−
+
−*** Classical Reasoner ***
+
−
+
−Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
+
−some limitations.  Blast_tac...
+
−  + ignores addss, addbefore, addafter; this restriction is intrinsic
+
−  + ignores elimination rules that don't have the correct format
+
−        (the conclusion MUST be a formula variable)
+
−  + ignores types, which can make HOL proofs fail
+
−  + rules must not require higher-order unification, e.g. apply_type in ZF
+
−    [message "Function Var's argument not a bound variable" relates to this]
+
−  + its proof strategy is more general but can actually be slower
+
−
+
−* substitution with equality assumptions no longer permutes other
+
−assumptions;
+
−
+
−* minor changes in semantics of addafter (now called addaltern); renamed
+
−setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
+
−(and access functions for it);
+
−
+
−* improved combination of classical reasoner and simplifier:
+
−  + functions for handling clasimpsets
+
−  + improvement of addss: now the simplifier is called _after_ the
+
−    safe steps.
+
−  + safe variant of addss called addSss: uses safe simplifications
+
−    _during_ the safe steps. It is more complete as it allows multiple
+
−    instantiations of unknowns (e.g. with slow_tac).
+
−
+
−*** Simplifier ***
+
−
+
−* added interface for simplification procedures (functions that
+
−produce *proven* rewrite rules on the fly, depending on current
+
−redex);
+
−
+
−* ordering on terms as parameter (used for ordered rewriting);
+
−
+
−* new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
+
−
+
−* the solver is now split into a safe and an unsafe part.
+
−This should be invisible for the normal user, except that the
+
−functions setsolver and addsolver have been renamed to setSolver and
+
−addSolver; added safe_asm_full_simp_tac;
+
−
+
−
+
−*** HOL ***
+
−
+
−* a generic induction tactic `induct_tac' which works for all datatypes and
+
−also for type `nat';
+
−
+
−* a generic case distinction tactic `exhaust_tac' which works for all
+
−datatypes and also for type `nat';
+
−
+
−* each datatype comes with a function `size';
+
−
+
−* patterns in case expressions allow tuple patterns as arguments to
+
−constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
+
−
+
−* primrec now also works with type nat;
+
−
+
−* recdef: a new declaration form, allows general recursive functions to be
+
−defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
+
−
+
−* the constant for negation has been renamed from "not" to "Not" to
+
−harmonize with FOL, ZF, LK, etc.;
+
−
+
−* HOL/ex/LFilter theory of a corecursive "filter" functional for
+
−infinite lists;
+
−
+
−* HOL/Modelcheck demonstrates invocation of model checker oracle;
+
−
+
−* HOL/ex/Ring.thy declares cring_simp, which solves equational
+
−problems in commutative rings, using axiomatic type classes for + and *;
+
−
+
−* more examples in HOL/MiniML and HOL/Auth;
+
−
+
−* more default rewrite rules for quantifiers, union/intersection;
+
−
+
−* a new constant `arbitrary == @x.False';
+
−
+
−* HOLCF/IOA replaces old HOL/IOA;
+
−
+
−* HOLCF changes: derived all rules and arities
+
−  + axiomatic type classes instead of classes
+
−  + typedef instead of faking type definitions
+
−  + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
+
−  + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
+
−  + eliminated the types void, one, tr
+
−  + use unit lift and bool lift (with translations) instead of one and tr
+
−  + eliminated blift from Lift3.thy (use Def instead of blift)
+
−  all eliminated rules are derived as theorems --> no visible changes ;
+
−
+
−
+
−*** ZF ***
+
−
+
−* ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
+
−rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
+
−as ZF_cs addSIs [equalityI];
+
−
+
−
+
−
+
−New in Isabelle94-7 (November 96)
+
−---------------------------------
+
−
+
−* allowing negative levels (as offsets) in prlev and choplev;
+
−
+
−* super-linear speedup for large simplifications;
+
−
+
−* FOL, ZF and HOL now use miniscoping: rewriting pushes
+
−quantifications in as far as possible (COULD MAKE EXISTING PROOFS
+
−FAIL); can suppress it using the command Delsimps (ex_simps @
+
−all_simps); De Morgan laws are also now included, by default;
+
−
+
−* improved printing of ==>  :  ~:
+
−
+
−* new object-logic "Sequents" adds linear logic, while replacing LK
+
−and Modal (thanks to Sara Kalvala);
+
−
+
−* HOL/Auth: correctness proofs for authentication protocols;
+
−
+
−* HOL: new auto_tac combines rewriting and classical reasoning (many
+
−examples on HOL/Auth);
+
−
+
−* HOL: new command AddIffs for declaring theorems of the form P=Q to
+
−the rewriter and classical reasoner simultaneously;
+
−
+
−* function uresult no longer returns theorems in "standard" format;
+
−regain previous version by: val uresult = standard o uresult;
+
−
+
−
+
−
+
−New in Isabelle94-6
+
−-------------------
+
−
+
−* oracles -- these establish an interface between Isabelle and trusted
+
−external reasoners, which may deliver results as theorems;
+
−
+
−* proof objects (in particular record all uses of oracles);
+
−
+
−* Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
+
−
+
−* "constdefs" section in theory files;
+
−
+
−* "primrec" section (HOL) no longer requires names;
+
−
+
−* internal type "tactic" now simply "thm -> thm Sequence.seq";
+
−
+
−
+
−
+
−New in Isabelle94-5
+
−-------------------
+
−
+
−* reduced space requirements;
+
−
+
−* automatic HTML generation from theories;
+
−
+
−* theory files no longer require "..." (quotes) around most types;
+
−
+
−* new examples, including two proofs of the Church-Rosser theorem;
+
−
+
−* non-curried (1994) version of HOL is no longer distributed;
+
−
+
−
+
−
+
−New in Isabelle94-4
+
−-------------------
+
−
+
−* greatly reduced space requirements;
+
−
+
−* theory files (.thy) no longer require \...\ escapes at line breaks;
+
−
+
−* searchable theorem database (see the section "Retrieving theorems" on
+
−page 8 of the Reference Manual);
+
−
+
−* new examples, including Grabczewski's monumental case study of the
+
−Axiom of Choice;
+
−
+
−* The previous version of HOL renamed to Old_HOL;
+
−
+
−* The new version of HOL (previously called CHOL) uses a curried syntax
+
−for functions.  Application looks like f a b instead of f(a,b);
+
−
+
−* Mutually recursive inductive definitions finally work in HOL;
+
−
+
−* In ZF, pattern-matching on tuples is now available in all abstractions and
+
−translates to the operator "split";
+
−
+
−
+
−
+
−New in Isabelle94-3
+
−-------------------
+
−
+
−* new infix operator, addss, allowing the classical reasoner to
+
−perform simplification at each step of its search.  Example:
+
−        fast_tac (cs addss ss)
+
−
+
−* a new logic, CHOL, the same as HOL, but with a curried syntax
+
−for functions.  Application looks like f a b instead of f(a,b).  Also pairs
+
−look like (a,b) instead of <a,b>;
+
−
+
−* PLEASE NOTE: CHOL will eventually replace HOL!
+
−
+
−* In CHOL, pattern-matching on tuples is now available in all abstractions.
+
−It translates to the operator "split".  A new theory of integers is available;
+
−
+
−* In ZF, integer numerals now denote two's-complement binary integers.
+
−Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
+
−
+
−* Many new examples: I/O automata, Church-Rosser theorem, equivalents
+
−of the Axiom of Choice;
+
−
+
−
+
−
+
−New in Isabelle94-2
+
−-------------------
+
−
+
−* Significantly faster resolution;
+
−
+
−* the different sections in a .thy file can now be mixed and repeated
+
−freely;
+
−
+
−* Database of theorems for FOL, HOL and ZF.  New
+
−commands including qed, qed_goal and bind_thm store theorems in the database.
+
−
+
−* Simple database queries: return a named theorem (get_thm) or all theorems of
+
−a given theory (thms_of), or find out what theory a theorem was proved in
+
−(theory_of_thm);
+
−
+
−* Bugs fixed in the inductive definition and datatype packages;
+
−
+
−* The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
+
−and HOL_dup_cs obsolete;
+
−
+
−* Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
+
−have been removed;
+
−
+
−* Simpler definition of function space in ZF;
+
−
+
−* new results about cardinal and ordinal arithmetic in ZF;
+
−
+
−* 'subtype' facility in HOL for introducing new types as subsets of existing
+
−types;
+
−
+
−
+
−$Id$