changeset 821 | 650ee089809b |
parent 793 | 0b5c5f568d74 |
child 1002 | 280ec187f8e1 |
--- a/src/FOL/IFOL.ML Wed Dec 21 13:36:02 1994 +0100 +++ b/src/FOL/IFOL.ML Fri Dec 23 10:52:25 1994 +0100 @@ -358,3 +358,9 @@ "[| (EX x.P(x))-->S; P(x)-->S ==> R |] ==> R" (fn major::prems=> [ (REPEAT (ares_tac ([exI, impI, major RS mp]@prems) 1)) ]); + +(*Courtesy Krzysztof Grabczewski*) +val major::prems = goal IFOL.thy "[| P|Q; P==>R; Q==>S |] ==> R|S"; +br (major RS disjE) 1; +by (REPEAT (eresolve_tac (prems RL [disjI1, disjI2]) 1)); +qed "disj_imp_disj";