src/HOLCF/Porder0.ML

Added filter_prems_tac

(*  Title:      HOLCF/Porder0.ML
    ID:         $Id$
    Author:     Oscar Slotosch
    Copyright   1997 Technische Universitaet Muenchen

    derive the characteristic axioms for the characteristic constants *)

open Porder0;

AddIffs [refl_less];

(* ------------------------------------------------------------------------ *)
(* minimal fixes least element                                              *)
(* ------------------------------------------------------------------------ *)
bind_thm("minimal2UU",allI RS (prove_goal thy "!x::'a::po. uu<<x==>uu=(@u.!y. u<<y)"
(fn prems =>
        [
        (cut_facts_tac prems 1),
        (rtac antisym_less 1),
        (etac spec 1),
        (res_inst_tac [("a","uu")] selectI2 1),
	(atac 1),
	(etac spec 1)
        ])));

(* ------------------------------------------------------------------------ *)
(* the reverse law of anti--symmetrie of <<                                 *)
(* ------------------------------------------------------------------------ *)

qed_goal "antisym_less_inverse" thy "(x::'a::po)=y ==> x << y & y << x"
(fn prems =>
        [
        (cut_facts_tac prems 1),
        (rtac conjI 1),
        ((rtac subst 1) THEN (rtac refl_less 2) THEN (atac 1)),
        ((rtac subst 1) THEN (rtac refl_less 2) THEN (etac sym 1))
        ]);


qed_goal "box_less" thy
"[| (a::'a::po) << b; c << a; b << d|] ==> c << d"
 (fn prems =>
        [
        (cut_facts_tac prems 1),
        (etac trans_less 1),
        (etac trans_less 1),
        (atac 1)
        ]);

Goal "((x::'a::po)=y) = (x << y & y << x)";
by (fast_tac (HOL_cs addSEs [antisym_less_inverse] addSIs [antisym_less]) 1);
qed "po_eq_conv";