src/FOL/FOL.ML
changeset 7355 4c43090659ca
parent 5159 8fc4fb20d70f
child 7529 fa534e4f7e49
--- a/src/FOL/FOL.ML	Wed Aug 25 20:42:01 1999 +0200
+++ b/src/FOL/FOL.ML	Wed Aug 25 20:45:19 1999 +0200
@@ -1,94 +1,8 @@
-(*  Title:      FOL/FOL.ML
-    ID:         $Id$
-    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
-    Copyright   1991  University of Cambridge
 
-Tactics and lemmas for FOL.thy (classical First-Order Logic)
-*)
+structure FOL =
+struct
+  val thy = the_context ();
+  val classical = classical;
+end;
 
 open FOL;
-
-
-val ccontr = FalseE RS classical;
-
-(*** Classical introduction rules for | and EX ***)
-
-qed_goal "disjCI" FOL.thy 
-   "(~Q ==> P) ==> P|Q"
- (fn prems=>
-  [ (rtac classical 1),
-    (REPEAT (ares_tac (prems@[disjI1,notI]) 1)),
-    (REPEAT (ares_tac (prems@[disjI2,notE]) 1)) ]);
-
-(*introduction rule involving only EX*)
-qed_goal "ex_classical" FOL.thy 
-   "( ~(EX x. P(x)) ==> P(a)) ==> EX x. P(x)"
- (fn prems=>
-  [ (rtac classical 1),
-    (eresolve_tac (prems RL [exI]) 1) ]);
-
-(*version of above, simplifying ~EX to ALL~ *)
-qed_goal "exCI" FOL.thy 
-   "(ALL x. ~P(x) ==> P(a)) ==> EX x. P(x)"
- (fn [prem]=>
-  [ (rtac ex_classical 1),
-    (resolve_tac [notI RS allI RS prem] 1),
-    (etac notE 1),
-    (etac exI 1) ]);
-
-qed_goal "excluded_middle" FOL.thy "~P | P"
- (fn _=> [ rtac disjCI 1, assume_tac 1 ]);
-
-(*For disjunctive case analysis*)
-fun excluded_middle_tac sP =
-    res_inst_tac [("Q",sP)] (excluded_middle RS disjE);
-
-qed_goal "case_split_thm" FOL.thy "[| P ==> Q; ~P ==> Q |] ==> Q"
-  (fn [p1,p2] => [rtac (excluded_middle RS disjE) 1,
-                  etac p2 1, etac p1 1]);
-
-(*HOL's more natural case analysis tactic*)
-fun case_tac a = res_inst_tac [("P",a)] case_split_thm;
-
-
-(*** Special elimination rules *)
-
-
-(*Classical implies (-->) elimination. *)
-qed_goal "impCE" FOL.thy 
-    "[| P-->Q;  ~P ==> R;  Q ==> R |] ==> R"
- (fn major::prems=>
-  [ (resolve_tac [excluded_middle RS disjE] 1),
-    (DEPTH_SOLVE (ares_tac (prems@[major RS mp]) 1)) ]);
-
-(*This version of --> elimination works on Q before P.  It works best for
-  those cases in which P holds "almost everywhere".  Can't install as
-  default: would break old proofs.*)
-qed_goal "impCE'" thy 
-    "[| P-->Q;  Q ==> R;  ~P ==> R |] ==> R"
- (fn major::prems=>
-  [ (resolve_tac [excluded_middle RS disjE] 1),
-    (DEPTH_SOLVE (ares_tac (prems@[major RS mp]) 1)) ]);
-
-(*Double negation law*)
-qed_goal "notnotD" FOL.thy "~~P ==> P"
- (fn [major]=>
-  [ (rtac classical 1), (eresolve_tac [major RS notE] 1) ]);
-
-qed_goal "contrapos2" FOL.thy "[| Q; ~ P ==> ~ Q |] ==> P" (fn [p1,p2] => [
-        rtac classical 1,
-        dtac p2 1,
-        etac notE 1,
-        rtac p1 1]);
-
-(*** Tactics for implication and contradiction ***)
-
-(*Classical <-> elimination.  Proof substitutes P=Q in 
-    ~P ==> ~Q    and    P ==> Q  *)
-qed_goalw "iffCE" FOL.thy [iff_def]
-    "[| P<->Q;  [| P; Q |] ==> R;  [| ~P; ~Q |] ==> R |] ==> R"
- (fn prems =>
-  [ (rtac conjE 1),
-    (REPEAT (DEPTH_SOLVE_1 
-        (etac impCE 1  ORELSE  mp_tac 1  ORELSE  ares_tac prems 1))) ]);
-