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NEWS

author | nipkow |

Thu, 24 Apr 1997 18:38:30 +0200 | |

changeset 3042 | 21cd332b65d3 |

parent 3006 | 8a1eb4531fbb |

child 3107 | 492a3d5d2b17 |

permissions | -rw-r--r-- |

induct_tac

Isabelle NEWS -- history of user-visible changes ================================================ 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; * 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 *** * 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); * token translations for modes "xterm" and "xterm_color" that display names in bold, underline etc. or colors (which requires a color version of xterm); * now supports alternative (named) syntax tables (parser and pretty printer); internal interface is provided by add_modesyntax(_i); * 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: new addss, auto_tac, functions for handling clasimpsets, ... Now, the simplification is safe (therefore moved to safe_step_tac) and thus more complete, as multiple instantiation of unknowns (with slow_tac). COULD MAKE EXISTING PROOFS FAIL; in case of problems with old proofs, use unsafe_addss and unsafe_auto_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'. * 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; * 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/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; * 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; $Id$