(*  Title:      HOL/Library/Refute.thy

    Author:     Tjark Weber

    Copyright   2003-2007

Basic setup and documentation for the 'refute' (and 'refute_params') command.

*)

header {* Refute *}

theory Refute

imports Hilbert_Choice List Sledgehammer

keywords "refute" :: diag and "refute_params" :: thy_decl

begin

ML_file "refute.ML"

setup Refute.setup

refute_params

 [itself = 1,

  minsize = 1,

  maxsize = 8,

  maxvars = 10000,

  maxtime = 60,

  satsolver = auto,

  no_assms = false]

text {*

\small

\begin{verbatim}

(* ------------------------------------------------------------------------- *)

(* REFUTE                                                                    *)

(*                                                                           *)

(* We use a SAT solver to search for a (finite) model that refutes a given   *)

(* HOL formula.                                                              *)

(* ------------------------------------------------------------------------- *)

(* ------------------------------------------------------------------------- *)

(* NOTE                                                                      *)

(*                                                                           *)

(* I strongly recommend that you install a stand-alone SAT solver if you     *)

(* want to use 'refute'.  For details see 'HOL/Tools/sat_solver.ML'.  If you *)

(* have installed (a supported version of) zChaff, simply set 'ZCHAFF_HOME'  *)

(* in 'etc/settings'.                                                        *)

(* ------------------------------------------------------------------------- *)

(* ------------------------------------------------------------------------- *)

(* USAGE                                                                     *)

(*                                                                           *)

(* See the file 'HOL/ex/Refute_Examples.thy' for examples.  The supported    *)

(* parameters are explained below.                                           *)

(* ------------------------------------------------------------------------- *)

(* ------------------------------------------------------------------------- *)

(* CURRENT LIMITATIONS                                                       *)

(*                                                                           *)

(* 'refute' currently accepts formulas of higher-order predicate logic (with *)

(* equality), including free/bound/schematic variables, lambda abstractions, *)

(* sets and set membership, "arbitrary", "The", "Eps", records and           *)

(* inductively defined sets.  Constants are unfolded automatically, and sort *)

(* axioms are added as well.  Other, user-asserted axioms however are        *)

(* ignored.  Inductive datatypes and recursive functions are supported, but  *)

(* may lead to spurious countermodels.                                       *)

(*                                                                           *)

(* The (space) complexity of the algorithm is non-elementary.                *)

(*                                                                           *)

(* Schematic type variables are not supported.                               *)

(* ------------------------------------------------------------------------- *)

(* ------------------------------------------------------------------------- *)

(* PARAMETERS                                                                *)

(*                                                                           *)

(* The following global parameters are currently supported (and required,    *)

(* except for "expect"):                                                     *)

(*                                                                           *)

(* Name          Type    Description                                         *)

(*                                                                           *)

(* "minsize"     int     Only search for models with size at least           *)

(*                       'minsize'.                                          *)

(* "maxsize"     int     If >0, only search for models with size at most     *)

(*                       'maxsize'.                                          *)

(* "maxvars"     int     If >0, use at most 'maxvars' boolean variables      *)

(*                       when transforming the term into a propositional     *)

(*                       formula.                                            *)

(* "maxtime"     int     If >0, terminate after at most 'maxtime' seconds.   *)

(*                       This value is ignored under some ML compilers.      *)

(* "satsolver"   string  Name of the SAT solver to be used.                  *)

(* "no_assms"    bool    If "true", assumptions in structured proofs are     *)

(*                       not considered.                                     *)

(* "expect"      string  Expected result ("genuine", "potential", "none", or *)

(*                       "unknown").                                         *)

(*                                                                           *)

(* The size of particular types can be specified in the form type=size       *)

(* (where 'type' is a string, and 'size' is an int).  Examples:              *)

(* "'a"=1                                                                    *)

(* "List.list"=2                                                             *)

(* ------------------------------------------------------------------------- *)

(* ------------------------------------------------------------------------- *)

(* FILES                                                                     *)

(*                                                                           *)

(* HOL/Tools/prop_logic.ML     Propositional logic                           *)

(* HOL/Tools/sat_solver.ML     SAT solvers                                   *)

(* HOL/Tools/refute.ML         Translation HOL -> propositional logic and    *)

(*                             Boolean assignment -> HOL model               *)

(* HOL/Refute.thy              This file: loads the ML files, basic setup,   *)

(*                             documentation                                 *)

(* HOL/SAT.thy                 Sets default parameters                       *)

(* HOL/ex/Refute_Examples.thy  Examples                                      *)

(* ------------------------------------------------------------------------- *)

\end{verbatim}

*}

end